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Batinic-Haberle, Ines

Positions:

Professor Emeritus of Radiation Oncology

Radiation Oncology
School of Medicine

Member of the Duke Cancer Institute

Duke Cancer Institute
School of Medicine

Education:

Ph.D. 1988

Ph.D. — University of Zagreb (Croatia)

Research Associate, Chemistry

Duke University

Grants:

New therapeutic strategy in reversing radiation-induced erectile dysfunction with prostate cancer pa-tients

Administered By
Radiation Oncology
AwardedBy
North Carolina Biotechnology Center
Role
Principal Investigator
Start Date
January 18, 2016
End Date
January 17, 2017

Treatment of Neuropathic Pain after SCI with a Catalytic Oxidoreductant

Administered By
Anesthesiology
AwardedBy
University of Alabama at Birmingham
Role
Co Investigator
Start Date
September 30, 2013
End Date
September 29, 2016

Heat and Radiation Effects on Tumor Microcirculation

Administered By
Radiation Oncology
AwardedBy
National Institutes of Health
Role
Investigator
Start Date
January 01, 1985
End Date
September 30, 2015

Fe porphyrin-based Redox Modulator in Experimental Stroke Outcome

Administered By
Radiation Oncology
AwardedBy
National Institutes of Health
Role
Principal Investigator
Start Date
April 01, 2013
End Date
March 31, 2015

Antioxidant Mimetic as a Mitigator of Radiation Induced Lung Injury

Administered By
Radiation Oncology
AwardedBy
National Institutes of Health
Role
Investigator
Start Date
September 01, 2010
End Date
February 28, 2013

Mechanism of hypoxia mediated radiation lung injury

Administered By
Radiation Oncology
AwardedBy
National Institutes of Health
Role
Investigator
Start Date
August 01, 2003
End Date
July 31, 2007

Developing Mn Porphyrins as a Treatment for ALS

Administered By
Biochemistry
AwardedBy
National Institute of Environmental Health Science
Role
Co Investigator
Start Date
May 01, 2005
End Date
April 30, 2007
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Publications:

Mechanism of the Antitumor and Radiosensitizing Effects of a Manganese Porphyrin, MnHex-2-PyP.

Cationic manganese (Mn)-substituted N-pyridylporphyrin-based potent mimics of the family of superoxide dismutases (SODs) protect normal tissues from injury related to ionizing radiation (IR) by reducing levels of reactive oxygen and nitrogen species (ROS/RNS). Furthermore, Mn-porphyrins have demonstrated antitumor and radiosensitizing effects on cancer cells by promoting IR-induced tumor vasculature damage and apoptotic processes. In this study, we explored the underlying mechanisms of Mn-porphyrin-mediated tumor radiosensitization using murine mammary carcinoma 4T1 and melanoma B16 cells in vitro and in vivo.Combination treatment with MnTnHex-2-PyP and IR substantially reduced cell viability, clonogenic cell survival, and DNA damage repair and synergistically increased IR-induced apoptosis of 4T1 and B16 cells. MnTnHex-2-PyP in combination with IR caused a significant delay in growth of 4T1 and B16 xenograft tumors. MnTnHex-2-PyP dose-dependently enhanced IR-mediated production of H2O2-derived species, but not superoxide. Catalase overexpression reversed MnTnHex-2-PyP-enhanced ROS production and apoptosis. Demonstrated suppression of phosphorylation of several mitogen-activated protein (MAP) kinases and activation of NF-κB by MnTnHex-2-PyP/IR, which presumably inhibited activation of the antiapoptotic pathway, are in agreement with our other data on the apoptosis of cancer cells. Innovation and Conclusions: MnTnHex-2-PyP exerted a radiosensitizing effect on 4T1 and B16 tumor models in vitro and in vivo via pro-oxidative actions and therefore bears a large therapeutic potential. When combined with IR, it attenuated DNA damage repair and triggered a shift from prosurvival pathways to apoptotic cell death, likely due to increased ROS production and disturbed cellular redox balance, acting at the level of nuclear factor κB (NF-κB). Antioxid. Redox Signal. 27, 1067-1082.

Authors
Shin, S-W; Choi, C; Lee, G-H; Son, A; Kim, S-H; Park, HC; Batinic-Haberle, I; Park, W
MLA Citation
Shin, S-W, Choi, C, Lee, G-H, Son, A, Kim, S-H, Park, HC, Batinic-Haberle, I, and Park, W. "Mechanism of the Antitumor and Radiosensitizing Effects of a Manganese Porphyrin, MnHex-2-PyP. (Accepted)" Antioxidants & redox signaling 27.14 (November 2017): 1067-1082.
PMID
28358581
Source
epmc
Published In
Antioxidants & Redox Signaling
Volume
27
Issue
14
Publish Date
2017
Start Page
1067
End Page
1082
DOI
10.1089/ars.2016.6889

Differences in Reperfusion-Induced Mitochondrial Oxidative Stress and Cell Death Between Hippocampal CA1 and CA3 Subfields Are Due to the Mitochondrial Thioredoxin System.

The susceptibility of CA1 over CA3 to damage from cerebral ischemia may be related to the differences in reactive oxygen species (ROS) production/removal between the two hippocampal subfields. We aimed to measure CA1/CA3 differences in net ROS production in real time in the first 30 min of reperfusion in pyramidal cells. We aimed to determine the underlying cause of the differential vulnerability of CA1 and CA3.Real-time determinations of mitochondrial H2O2 and, independently, glutathione (GSH) redox status from roGFP-based probes in individual pyramidal cells in organotypic hippocampal cultures during oxygen-glucose deprivation (OGD)-reperfusion (RP) demonstrate a significantly more oxidizing environment during RP in CA1 than CA3 mitochondria. Protein levels (immunohistochemistry and Western blots), roGFP2-based probe measurements during controlled mitochondrial production of ROS, and thioredoxin reductase (TrxR) inhibition by auranofin are consistent with a more effective mitochondrial thioredoxin (Trx) system in CA3. Inhibition of TrxR eliminates the differences in redox status and cell death between the regions. Overexpression of cytosolic Trx1 does not influence mitochondrial H2O2 production.Real-time changes of mitochondrial H2O2 and GSH in tissue cultures during early RP, and also during controlled production of superoxide and peroxide, reveal significant differences between CA1 and CA3. The mitochondrial Trx system is responsible for the observed differences during RP as well as for delayed cell death 18 h afterward.Greater mitochondrial Trx efficacy in CA3 pyramidal cells results in less vulnerability to ischemia/reperfusion because of the less oxidizing environment in CA3 mitochondria during RP. Antioxid. Redox Signal. 27, 534-549.

Authors
Yin, B; Barrionuevo, G; Batinic-Haberle, I; Sandberg, M; Weber, SG
MLA Citation
Yin, B, Barrionuevo, G, Batinic-Haberle, I, Sandberg, M, and Weber, SG. "Differences in Reperfusion-Induced Mitochondrial Oxidative Stress and Cell Death Between Hippocampal CA1 and CA3 Subfields Are Due to the Mitochondrial Thioredoxin System." Antioxidants & redox signaling 27.9 (September 2017): 534-549.
PMID
28129719
Source
epmc
Published In
Antioxidants & Redox Signaling
Volume
27
Issue
9
Publish Date
2017
Start Page
534
End Page
549
DOI
10.1089/ars.2016.6706

A novel redox regulator, MnTnBuOE-2-PyP5+, enhances normal hematopoietic stem/progenitor cell function.

The signaling of reactive oxygen species (ROS) is essential for the maintenance of normal cellular function. However, whether and how ROS regulate stem cells are unclear. Here, we demonstrate that, in transgenic mice expressing the human manganese superoxide dismutase (MnSOD) gene, a scavenger of ROS in mitochondria, the number and function of mouse hematopoietic stem/progenitor cells (HSPC) under physiological conditions are enhanced. Importantly, giving MnTnBuOE-2-PyP5+(MnP), a redox- active MnSOD mimetic, to mouse primary bone marrow cells or to C57B/L6 mice significantly enhances the number of HSPCs. Mechanistically, MnP reduces superoxide to hydrogen peroxide, which activates intracellular Nrf2 signaling leading to the induction of antioxidant enzymes, including MnSOD and catalase, and mitochondrial uncoupling protein 3. The results reveal a novel role of ROS signaling in regulating stem cell function, and suggest a possible beneficial effect of MnP in treating pathological bone marrow cell loss and in increasing stem cell population for bone marrow transplantation.

Authors
Zhao, Y; Carroll, DW; You, Y; Chaiswing, L; Wen, R; Batinic-Haberle, I; Bondada, S; Liang, Y; St Clair, DK
MLA Citation
Zhao, Y, Carroll, DW, You, Y, Chaiswing, L, Wen, R, Batinic-Haberle, I, Bondada, S, Liang, Y, and St Clair, DK. "A novel redox regulator, MnTnBuOE-2-PyP5+, enhances normal hematopoietic stem/progenitor cell function." Redox biology 12 (August 2017): 129-138.
PMID
28231483
Source
epmc
Published In
Redox Biology
Volume
12
Publish Date
2017
Start Page
129
End Page
138
DOI
10.1016/j.redox.2017.02.005

CNS bioavailability and radiation protection of normal hippocampal neurogenesis by a lipophilic Mn porphyrin-based superoxide dismutase mimic, MnTnBuOE-2-PyP5.

Although radiation therapy can be effective against cancer, potential damage to normal tissues limits the amount that can be safely administered. In central nervous system (CNS), radiation damage to normal tissues is presented, in part, as suppressed hippocampal neurogenesis and impaired cognitive functions. Mn porphyrin (MnP)-based redox active drugs have demonstrated differential effects on cancer and normal tissues in experimental animals that lead to protection of normal tissues and radio- and chemo-sensitization of cancers. To test the efficacy of MnPs in CNS radioprotection, we first examined the tissue levels of three different MnPs - MnTE-2-PyP5+(MnE), MnTnHex-2-PyP5+(MnHex), and MnTnBuOE-2-PyP5+(MnBuOE). Nanomolar concentrations of MnHex and MnBuOE were detected in various brain regions after daily subcutaneous administration, and MnBuOE was well tolerated at a daily dose of 3mg/kg. Administration of MnBuOE for one week before cranial irradiation and continued for one week afterwards supported production and long-term survival of newborn neurons in the hippocampal dentate gyrus. MnP-driven S-glutathionylation in cortex and hippocampus showed differential responses to MnP administration and radiation in these two brain regions. A better understanding of how preserved hippocampal neurogenesis correlates with cognitive functions following cranial irradiation will be helpful in designing better MnP-based radioprotection strategies.

Authors
Leu, D; Spasojevic, I; Nguyen, H; Deng, B; Tovmasyan, A; Weitner, T; Sampaio, RS; Batinic-Haberle, I; Huang, T-T
MLA Citation
Leu, D, Spasojevic, I, Nguyen, H, Deng, B, Tovmasyan, A, Weitner, T, Sampaio, RS, Batinic-Haberle, I, and Huang, T-T. "CNS bioavailability and radiation protection of normal hippocampal neurogenesis by a lipophilic Mn porphyrin-based superoxide dismutase mimic, MnTnBuOE-2-PyP5." Redox biology 12 (August 2017): 864-871.
PMID
28454069
Source
epmc
Published In
Redox Biology
Volume
12
Publish Date
2017
Start Page
864
End Page
871
DOI
10.1016/j.redox.2017.04.027

Potential for a novel manganese porphyrin compound as adjuvant canine lymphoma therapy.

Manganese porphyrins are redox-active drugs and superoxide dismutase mimics, which have been shown to chemosensitize lymphoma, a cancer which frequently occurs in dogs. This study aimed to identify critical information regarding the pharmacokinetics and toxicity of Mn(III) meso-tetrakis (N-n-butoxyetylpyridium-2-yl) porphyrin, (MnTnBuOE-2-PyP5+, MnBuOE) in dogs as a prelude to a clinical trial in canine lymphoma patients.A single-dose pharmacokinetic (PK) study in normal dogs was performed to determine the plasma half-life (t 1/2) of MnBuOE. A dose reduction study was performed to establish the maximum tolerated dose (MTD) of MnBuOE. The safety and PK of a multi-dosing protocol was assessed.Peak plasma drug concentration occurred 30 min post-injection. The t 1/2 was defined as 7 h. MnBuOE induced an anaphylactic reaction and prolonged tachycardia. The MTD was defined as 0.25 mg/kg. The dogs were given MTD 3×/week for 2-3 weeks. The highest recorded tissue drug levels were in the lymph nodes (4-6 μM), followed by kidney and liver (2.5, 2.0 uM, respectively).We obtained critical information regarding the PK and toxicity of MnBuOE in dogs. The acute drug reaction and tachycardia post-injection have not been described in other species and may be specific to canines. The high tissue drug levels in lymph nodes have not been previously reported. MnBuOE accumulation in lymph nodes has important implications for the utility of adjuvant MnBuOE to treat lymphoma. With MnBuOE lymph node accumulation, reduction in the dose and/or administration frequency could be possible, leading to reduced toxicity.

Authors
Boss, MK; Dewhirst, MW; Sampaio, RS; Bennett, A; Tovmasyan, A; Berman, KG; Beaven, AW; Rizzieri, DA; Batinic-Haberle, I; Hauck, ML; Spasojevic, I
MLA Citation
Boss, MK, Dewhirst, MW, Sampaio, RS, Bennett, A, Tovmasyan, A, Berman, KG, Beaven, AW, Rizzieri, DA, Batinic-Haberle, I, Hauck, ML, and Spasojevic, I. "Potential for a novel manganese porphyrin compound as adjuvant canine lymphoma therapy." Cancer chemotherapy and pharmacology 80.2 (August 2017): 421-431.
PMID
28685347
Source
epmc
Published In
Cancer Chemotherapy and Pharmacology
Volume
80
Issue
2
Publish Date
2017
Start Page
421
End Page
431
DOI
10.1007/s00280-017-3372-z

Inhibition of the Continuum of Radiation-Induced Normal Tissue Injury by a Redox-Active Mn Porphyrin.

Normal tissue damage after head and neck radiotherapy involves a continuum of pathologic events to the mucosa, tongue and salivary glands. We examined the radioprotective effects of MnBuOE, a redox-active manganese porphyrin, at three stages of normal tissue damage: immediate (leukocyte endothelial cell [L/E] interactions), early (mucositis) and late (xerostomia and fibrosis) after treatment. In this study, mice received 0 or 9 Gy irradiation to the oral cavity and salivary glands ± MnBuOE treatment. Changes in leukocyte-endothelial cell interactions were measured 24 h postirradiation. At 11 days postirradiation, mucositis was assessed with a cathepsin-sensitive near-infrared optical probe. Stimulated saliva production was quantified at 11 weeks postirradiation. Finally, histological analyses were conducted to assess the extent of long-term effects in salivary glands at 12 weeks postirradiation. MnBuOE reduced oral mucositis, xerostomia and salivary gland fibrosis after irradiation. Additionally, although we have previously shown that MnBuOE does not interfere with tumor control at high doses when administered with radiation alone, most head and neck cancer patients will be treated with the combinations of radiotherapy and cisplatin. Therefore, we also evaluated whether MnBuOE would protect tumors against radiation and cisplatin using tumor growth delay as an endpoint. Using a range of radiation doses, we saw no evidence that MnBuOE protected tumors from radiation and cisplatin. We conclude that MnBuOE radioprotects normal tissue at both early and late time points, without compromising anti-tumor effects of radiation and cisplatin.

Authors
Birer, SR; Lee, C-T; Choudhury, KR; Young, KH; Spasojevic, I; Batinic-Haberle, I; Crapo, JD; Dewhirst, MW; Ashcraft, KA
MLA Citation
Birer, SR, Lee, C-T, Choudhury, KR, Young, KH, Spasojevic, I, Batinic-Haberle, I, Crapo, JD, Dewhirst, MW, and Ashcraft, KA. "Inhibition of the Continuum of Radiation-Induced Normal Tissue Injury by a Redox-Active Mn Porphyrin." Radiation research 188.1 (July 2017): 94-104.
PMID
28517962
Source
epmc
Published In
Radiation Research
Volume
188
Issue
1
Publish Date
2017
Start Page
94
End Page
104
DOI
10.1667/rr14757.1.s1

Challenges encountered during development of Mn porphyrin-based, potent redox-active drug and superoxide dismutase mimic, MnTnBuOE-2-PyP5+, and its alkoxyalkyl analogues.

We disclose here the studies that preceded and guided the preparation of the metal-based, redox-active therapeutic Mn(III) meso-tetrakis(N-n-butoxyethylpyridyl)porphyrin, MnTnBuOE-2-PyP5+ (BMX-001), which is currently in Phase I/II Clinical Trials at Duke University (USA) as a radioprotector of normal tissues in cancer patients. N-substituted pyridylporphyrins are ligands for Mn(III) complexes that are among the most potent superoxide dismutase mimics thus far synthesized. To advance their design, thereby improving their physical and chemical properties and bioavailability/toxicity profiles, we undertook a systematic study on placing oxygen atoms into N-alkylpyridyl chains via alkoxyalkylation reaction. For the first time we show here the unforeseen structural rearrangement that happens during the alkoxyalkylation reaction by the corresponding tosylates. Comprehensive experimental and computational approaches were employed to solve the rearrangement mechanism involved in quaternization of pyridyl nitrogens, which, instead of a single product, led to a variety of mixed N-alkoxyalkylated and N-alkylated pyridylporphyrins. The rearrangement mechanism involves the formation of an intermediate alkyl oxonium cation in a chain-length-dependent manner, which subsequently drives differential kinetics and thermodynamics of competing N-alkoxyalkylation versus in situ N-alkylation. The use of alkoxyalkyl tosylates, of different length of alkyl fragments adjacent to oxygen atom, allowed us to identify the set of alkyl fragments that would result in the synthesis of a single compound of high purity and excellent therapeutic potential.

Authors
Rajic, Z; Tovmasyan, A; de Santana, OL; Peixoto, IN; Spasojevic, I; do Monte, SA; Ventura, E; Rebouças, JS; Batinic-Haberle, I
MLA Citation
Rajic, Z, Tovmasyan, A, de Santana, OL, Peixoto, IN, Spasojevic, I, do Monte, SA, Ventura, E, Rebouças, JS, and Batinic-Haberle, I. "Challenges encountered during development of Mn porphyrin-based, potent redox-active drug and superoxide dismutase mimic, MnTnBuOE-2-PyP5+, and its alkoxyalkyl analogues." Journal of inorganic biochemistry 169 (April 2017): 50-60.
PMID
28131001
Source
epmc
Published In
Journal of Inorganic Biochemistry
Volume
169
Publish Date
2017
Start Page
50
End Page
60
DOI
10.1016/j.jinorgbio.2017.01.003

Optimizing Zn porphyrin-based photosensitizers for efficient antibacterial photodynamic therapy.

Efficient photodynamic inactivation of microbes requires highly efficient photosensitizers which kill microbial cells, but spare host tissues. One way to achieve such selectivity is to use photosensitizers that are rapidly taken up by microbes and, when applied at low concentrations, efficiently kill them after a short illumination. Design of such photosensitizers requires insight into molecular properties which are critical for antimicrobial photo-efficiency. This study explores the contribution of molecular shape and exposure of charges, to the antimicrobial activity of tetra-cationic Zn porphyrin-based photosensitizers.Two isomers, ortho (2) and meta (3) hexyl and octyl Zn(II) meso-tetrakis(N-alkylpyridinium-2(3)-yl)porphyrins [ZnTnHex-2(3)-PyP and ZnTnOct-2(3)-PyP] were compared for uptake and photo-efficiency against a Gram-negative bacterium, Escherichia coli.The highest photo-efficiency was displayed by the meta hexyl derivative. At concentration as low as 1.0μM and during only 5min of preincubation with the cells, ZnTnHex-3-PyP decreased viable cell number by about 6log10 after only 5min of illumination. Since bacterial suspensions were thoroughly washed after preincubation with photosensitizers, this effect can be attributed only to photosensitizer taken up or bound to E. coli. Irrespective of its highest uptake by the cells, the octyl meta isomer, ZnTnOct-3-PyP, did not show higher antibacterial activity than the shorter-chain hexyl derivative, ZnTnHex-3-PyP.Efficiency and eventually selectivity of antimicrobial photosensitizers can be improved by optimizing the shape of the molecule and the position of electric charges. Increasing lipophilicity and cellular uptake per se, does not necessarily materialize in high antimicrobial efficiency of the photosensitizer.

Authors
Alenezi, K; Tovmasyan, A; Batinic-Haberle, I; Benov, LT
MLA Citation
Alenezi, K, Tovmasyan, A, Batinic-Haberle, I, and Benov, LT. "Optimizing Zn porphyrin-based photosensitizers for efficient antibacterial photodynamic therapy." Photodiagnosis and photodynamic therapy 17 (March 2017): 154-159.
PMID
27888164
Source
epmc
Published In
Photodiagnosis and Photodynamic Therapy
Volume
17
Publish Date
2017
Start Page
154
End Page
159
DOI
10.1016/j.pdpdt.2016.11.009

Important cellular targets for antimicrobial photodynamic therapy.

The persistent problem of antibiotic resistance has created a strong demand for new methods for therapy and disinfection. Photodynamic inactivation (PDI) of microbes has demonstrated promising results for eradication of antibiotic-resistant strains. PDI is based on the use of a photosensitive compound (photosensitizer, PS), which upon illumination with visible light generates reactive species capable of damaging and killing microorganisms. Since photogenerated reactive species are short lived, damage is limited to close proximity of the PS. It is reasonable to expect that the larger the number of damaged targets is and the greater their variety is, the higher the efficiency of PDI is and the lower the chances for development of resistance are. Exact molecular mechanisms and specific targets whose damage is essential for microbial inactivation have not been unequivocally established. Two main cellular components, DNA and plasma membrane, are regarded as the most important PDI targets. Using Zn porphyrin-based PSs and Escherichia coli as a model Gram-negative microorganism, we demonstrate that efficient photoinactivation of bacteria can be achieved without detectable DNA modification. Among the cellular components which are modified early during illumination and constitute key PDI targets are cytosolic enzymes, membrane-bound protein complexes, and the plasma membrane. As a result, membrane barrier function is lost, and energy and reducing equivalent production is disrupted, which in turn compromises cell defense mechanisms, thus augmenting the photoinduced oxidative injury. In conclusion, high PDI antimicrobial effectiveness does not necessarily require impairment of a specific critical cellular component and can be achieved by inducing damage to multiple cellular targets.

Authors
Awad, MM; Tovmasyan, A; Craik, JD; Batinic-Haberle, I; Benov, LT
MLA Citation
Awad, MM, Tovmasyan, A, Craik, JD, Batinic-Haberle, I, and Benov, LT. "Important cellular targets for antimicrobial photodynamic therapy." Applied microbiology and biotechnology 100.17 (September 2016): 7679-7688.
PMID
27221289
Source
epmc
Published In
Applied Microbiology and Biotechnology
Volume
100
Issue
17
Publish Date
2016
Start Page
7679
End Page
7688
DOI
10.1007/s00253-016-7632-3

Neurobehavioral radiation mitigation to standard brain cancer therapy regimens by Mn(III) n-butoxyethylpyridylporphyrin-based redox modifier.

Combinations of radiotherapy (RT) and chemotherapy have shown efficacy toward brain tumors. However, therapy-induced oxidative stress can damage normal brain tissue, resulting in both progressive neurocognitive loss and diminished quality of life. We have recently shown that MnTnBuOE-2-PyP(5+) (Mn(III)meso-tetrakis(N-n-butoxyethylpyridinium -2-yl)porphyrin) rescued RT-induced white matter damage in cranially-irradiated mice. Radiotherapy is not used in isolation for treatment of brain tumors; temozolomide is the standard-of-care for adult glioblastoma, whereas cisplatin is often used for treatment of pediatric brain tumors. Therefore, we evaluated the brain radiation mitigation ability of MnTnBuOE-2-PyP(5+) after either temozolomide or cisplatin was used singly or in combination with 10 Gy RT. MnTnBuOE-2-PyP(5+) accumulated in brains at low nanomolar levels. Histological and neurobehavioral testing showed a drastic decrease (1) of axon density in the corpus callosum and (2) rotorod and running wheel performance in the RT only treatment group, respectively. MnTnBuOE-2-PyP(5+) completely rescued this phenotype in irradiated animals. In the temozolomide groups, temozolomide/ RT treatment resulted in further decreased rotorod responses over RT alone. Again, MnTnBuOE-2-PyP(5+) treatment rescued the negative effects of both temozolomide ± RT on rotorod performance. While the cisplatin-treated groups did not give similar results as the temozolomide groups, inclusion of MnTnBuOE-2-PyP(5+) did not negatively affect rotorod performance. Additionally, MnTnBuOE-2-PyP(5+) sensitized glioblastomas to either RT ± temozolomide in flank tumor models. Mice treated with both MnTnBuOE-2-PyP(5+) and radio-/chemo-therapy herein demonstrated brain radiation mitigation. MnTnBuOE-2-PyP(5+) may well serve as a normal tissue radio-/chemo-mitigator adjuvant therapy to standard brain cancer treatment regimens. Environ. Mol. Mutagen. 57:372-381, 2016. © 2016 Wiley Periodicals, Inc.

Authors
Weitzel, DH; Tovmasyan, A; Ashcraft, KA; Boico, A; Birer, SR; Roy Choudhury, K; Herndon, J; Rodriguiz, RM; Wetsel, WC; Peters, KB; Spasojevic, I; Batinic-Haberle, I; Dewhirst, MW
MLA Citation
Weitzel, DH, Tovmasyan, A, Ashcraft, KA, Boico, A, Birer, SR, Roy Choudhury, K, Herndon, J, Rodriguiz, RM, Wetsel, WC, Peters, KB, Spasojevic, I, Batinic-Haberle, I, and Dewhirst, MW. "Neurobehavioral radiation mitigation to standard brain cancer therapy regimens by Mn(III) n-butoxyethylpyridylporphyrin-based redox modifier." Environmental and molecular mutagenesis 57.5 (June 2016): 372-381.
PMID
27224425
Source
epmc
Published In
Environmental and Molecular Mutagenesis
Volume
57
Issue
5
Publish Date
2016
Start Page
372
End Page
381
DOI
10.1002/em.22021

Opinion on Schmidt et al.

Authors
Batinic-Haberle, I; Tovmasyan, A; Spasojevic, I
MLA Citation
Batinic-Haberle, I, Tovmasyan, A, and Spasojevic, I. "Opinion on Schmidt et al." Antioxidants & redox signaling 24.9 (March 2016): 518-524. (Letter)
PMID
26857355
Source
epmc
Published In
Antioxidants & Redox Signaling
Volume
24
Issue
9
Publish Date
2016
Start Page
518
End Page
524
DOI
10.1089/ars.2015.6623

Redox-Active Mn Porphyrin-based Potent SOD Mimic, MnTnBuOE-2-PyP(5+), Enhances Carbenoxolone-Mediated TRAIL-Induced Apoptosis in Glioblastoma Multiforme.

Glioblastoma multiforme is the most malignant tumor of the brain and is challenging to treat due to its highly invasive nature and heterogeneity. Malignant brain tumor displays high metabolic activity which perturbs its redox environment and in turn translates to high oxidative stress. Thus, pushing the oxidative stress level to achieve the maximum tolerable threshold that induces cell death is a potential strategy for cancer therapy. Previously, we have shown that gap junction inhibitor, carbenoxolone (CBX), is capable of enhancing tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) -induced apoptosis in glioma cells. Since CBX is known to induce oxidative stress, we hypothesized that the addition of another potent mediator of oxidative stress, powerful SOD mimic MnTnBuOE-2-PyP(5+) (MnBuOE), could further enhance TRAIL-driven therapeutic efficacy in glioma cells. Our results showed that combining TRAIL + CBX with MnBuOE significantly enhances cell death of glioma cell lines and this enhancement could be further potentiated by CBX pretreatment. MnBuOE-driven cytotoxicity is due to its ability to take advantage of oxidative stress imposed by CBX + TRAIL system, and enhance it in the presence of endogenous reductants, ascorbate and thiol, thereby producing cytotoxic H2O2, and in turn inducing death of glioma cells but not normal astrocytes. Most importantly, combination treatment significantly reduces viability of TRAIL-resistant Asian patient-derived glioma cells, thus demonstrating the potential clinical use of our therapeutic system. It was reported that H2O2 is involved in membrane depolarization-based sensitization of cancer cells toward TRAIL. MnBuOE is entering Clinical Trials as a normal brain radioprotector in glioma patients at Duke University increasing Clinical relevance of our studies.

Authors
Yulyana, Y; Tovmasyan, A; Ho, IAW; Sia, KC; Newman, JP; Ng, WH; Guo, CM; Hui, KM; Batinic-Haberle, I; Lam, PYP
MLA Citation
Yulyana, Y, Tovmasyan, A, Ho, IAW, Sia, KC, Newman, JP, Ng, WH, Guo, CM, Hui, KM, Batinic-Haberle, I, and Lam, PYP. "Redox-Active Mn Porphyrin-based Potent SOD Mimic, MnTnBuOE-2-PyP(5+), Enhances Carbenoxolone-Mediated TRAIL-Induced Apoptosis in Glioblastoma Multiforme." Stem cell reviews 12.1 (February 2016): 140-155.
PMID
26454429
Source
epmc
Published In
Stem Cell Reviews and Reports
Volume
12
Issue
1
Publish Date
2016
Start Page
140
End Page
155
DOI
10.1007/s12015-015-9628-2

Novel role of 4-hydroxy-2-nonenal in AIFm2-mediated mitochondrial stress signaling.

Cardiovascular complications are major side effects of many anticancer drugs. Accumulated evidence indicates that oxidative stress in mitochondria plays an important role in cardiac injury, but how mitochondrial redox mechanisms are involved in cardiac dysfunction remains unclear. Here, we demonstrate that 4-hydroxy-2-nonenal (HNE) activates the translocation of the mitochondrial apoptosis inducing factor (AIFm2) and facilitates apoptosis in heart tissue of mice and humans. Doxorubicin treatments significantly enhance cardiac levels of HNE and AIFm2. HNE adduction of AIFm2 inactivates the NADH oxidoreductase activity of AIFm2 and facilitates its translocation from mitochondria. His 174 on AIFm2 is the critical target of HNE adduction that triggers this functional switch. HNE adduction and translocation of AIFm2 from mitochondria upon Doxorubicin treatment are attenuated by superoxide dismutase mimetics. These results identify a previously unrecognized role of HNE with important consequences for mitochondrial stress signaling, heart failure, and the side effects of cancer therapy.

Authors
Miriyala, S; Thippakorn, C; Chaiswing, L; Xu, Y; Noel, T; Tovmasyan, A; Batinic-Haberle, I; Vander Kooi, CW; Chi, W; Latif, AA; Panchatcharam, M; Prachayasittikul, V; Butterfield, DA; Vore, M; Moscow, J; St Clair, DK
MLA Citation
Miriyala, S, Thippakorn, C, Chaiswing, L, Xu, Y, Noel, T, Tovmasyan, A, Batinic-Haberle, I, Vander Kooi, CW, Chi, W, Latif, AA, Panchatcharam, M, Prachayasittikul, V, Butterfield, DA, Vore, M, Moscow, J, and St Clair, DK. "Novel role of 4-hydroxy-2-nonenal in AIFm2-mediated mitochondrial stress signaling." Free radical biology & medicine 91 (February 2016): 68-80.
PMID
26689472
Source
epmc
Published In
Free Radical Biology & Medicine
Volume
91
Publish Date
2016
Start Page
68
End Page
80
DOI
10.1016/j.freeradbiomed.2015.12.002

Novel role of 4-hydroxy-2-nonenal in AIFm2-mediated mitochondrial stress signaling

Authors
Miriyala, S; Thippakorn, C; Chaiswing, L; Xu, Y; Noel, T; Tovmasyan, A; Batinic-Haberle, I; Kooi, CWV; Chi, W; Latif, AA; Panchatcharam, M; Prachayasittikul, V; Butterfield, DA; Vore, M; Moscow, J; St Clair, DK
MLA Citation
Miriyala, S, Thippakorn, C, Chaiswing, L, Xu, Y, Noel, T, Tovmasyan, A, Batinic-Haberle, I, Kooi, CWV, Chi, W, Latif, AA, Panchatcharam, M, Prachayasittikul, V, Butterfield, DA, Vore, M, Moscow, J, and St Clair, DK. "Novel role of 4-hydroxy-2-nonenal in AIFm2-mediated mitochondrial stress signaling." FREE RADICAL BIOLOGY AND MEDICINE 91 (February 2016): 68-80.
Source
wos-lite
Published In
Free Radical Biology & Medicine
Volume
91
Publish Date
2016
Start Page
68
End Page
80
DOI
10.1016/j.freeradbiomed.l.2015.12.002

Ochratoxin A-induced cytotoxicity, genotoxicity and reactive oxygen species in kidney cells: An integrative approach of complementary endpoints.

Ochratoxin A (OTA) is a well-known nephrotoxic and potential carcinogenic agent but no consensus about the molecular mechanisms underlying its deleterious effects has been reached yet. The aim of this study is to integrate several endpoints concerning OTA-induced toxicological effects in Vero kidney cells in order to obtain additional mechanistic data, especially regarding the influence of reactive oxygen species (ROS). One innovative aspect of this work is the use of the superoxide dismutase mimic (SODm) MnTnHex-2-PyP as a mechanistic tool to clarify the involvement of oxidative stress in OTA toxicity. The results showed concentration and time-dependent cytotoxic effects of OTA (crystal violet, neutral red and LDH leakage assays). While the SODm mildly increased cell viability, trolox and ascorbic acid had no effect with regards to this endpoint. OTA induced micronuclei formation. Using the FPG modified comet assay, OTA modestly increased the % of DNA in tail, revealing the presence of oxidative DNA lesions. This mycotoxin increased apoptosis, which was attenuated by SODm. In addition, the SODm decreased the ROS accumulation observed in DHE assay. Taken together, our data suggest that ROS partially contribute to the cytotoxicity and genotoxicity of OTA, although other mechanisms may be relevant in OTA-induced deleterious effects.

Authors
Costa, JG; Saraiva, N; Guerreiro, PS; Louro, H; Silva, MJ; Miranda, JP; Castro, M; Batinic-Haberle, I; Fernandes, AS; Oliveira, NG
MLA Citation
Costa, JG, Saraiva, N, Guerreiro, PS, Louro, H, Silva, MJ, Miranda, JP, Castro, M, Batinic-Haberle, I, Fernandes, AS, and Oliveira, NG. "Ochratoxin A-induced cytotoxicity, genotoxicity and reactive oxygen species in kidney cells: An integrative approach of complementary endpoints." Food and chemical toxicology : an international journal published for the British Industrial Biological Research Association 87 (January 2016): 65-76.
PMID
26627377
Source
epmc
Published In
Food and Chemical Toxicology
Volume
87
Publish Date
2016
Start Page
65
End Page
76
DOI
10.1016/j.fct.2015.11.018

Anticancer therapeutic potential of Mn porphyrin/ascorbate system.

Ascorbate (Asc) as a single agent suppressed growth of several tumor cell lines in a mouse model. It has been tested in a Phase I Clinical Trial on pancreatic cancer patients where it exhibited no toxicity to normal tissue yet was of only marginal efficacy. The mechanism of its anticancer effect was attributed to the production of tumoricidal hydrogen peroxide (H2O2) during ascorbate oxidation catalyzed by endogenous metalloproteins. The amount of H2O2 could be maximized with exogenous catalyst that has optimized properties for such function and is localized within tumor. Herein we studied 14 Mn porphyrins (MnPs) which differ vastly with regards to their redox properties, charge, size/bulkiness and lipophilicity. Such properties affect the in vitro and in vivo ability of MnPs (i) to catalyze ascorbate oxidation resulting in the production of H2O2; (ii) to subsequently employ H2O2 in the catalysis of signaling proteins oxidations affecting cellular survival pathways; and (iii) to accumulate at site(s) of interest. The metal-centered reduction potential of MnPs studied, E1/2 of Mn(III)P/Mn(II)P redox couple, ranged from -200 to +350 mV vs NHE. Anionic and cationic, hydrophilic and lipophilic as well as short- and long-chained and bulky compounds were explored. Their ability to catalyze ascorbate oxidation, and in turn cytotoxic H2O2 production, was explored via spectrophotometric and electrochemical means. Bell-shape structure-activity relationship (SAR) was found between the initial rate for the catalysis of ascorbate oxidation, vo(Asc)ox and E1/2, identifying cationic Mn(III) N-substituted pyridylporphyrins with E1/2>0 mV vs NHE as efficient catalysts for ascorbate oxidation. The anticancer potential of MnPs/Asc system was subsequently tested in cellular (human MCF-7, MDA-MB-231 and mouse 4T1) and animal models of breast cancer. At the concentrations where ascorbate (1mM) and MnPs (1 or 5 µM) alone did not trigger any alteration in cell viability, combined treatment suppressed cell viability up to 95%. No toxicity was observed with normal human breast epithelial HBL-100 cells. Bell-shape relationship, essentially identical to vo(Asc)oxvs E1/2, was also demonstrated between MnP/Asc-controlled cytotoxicity and E1/2-controlled vo(Asc)ox. Magnetic resonance imaging studies were conducted to explore the impact of ascorbate on T1-relaxivity. The impact of MnP/Asc on intracellular thiols and on GSH/GSSG and Cys/CySS ratios in 4T1 cells was assessed and cellular reduction potentials were calculated. The data indicate a significant increase in cellular oxidative stress induced by MnP/Asc. Based on vo(Asc)oxvs E1/2 relationships and cellular toxicity, MnTE-2-PyP(5+) was identified as the best catalyst among MnPs studied. Asc and MnTE-2-PyP(5+) were thus tested in a 4T1 mammary mouse flank tumor model. The combination of ascorbate (4 g/kg) and MnTE-2-PyP(5+) (0.2mg/kg) showed significant suppression of tumor growth relative to either MnTE-2-PyP(5+) or ascorbate alone. About 7-fold higher accumulation of MnTE-2-PyP(5+) in tumor vs normal tissue was found to contribute largely to the anticancer effect.

Authors
Tovmasyan, A; Sampaio, RS; Boss, M-K; Bueno-Janice, JC; Bader, BH; Thomas, M; Reboucas, JS; Orr, M; Chandler, JD; Go, Y-M; Jones, DP; Venkatraman, TN; Haberle, S; Kyui, N; Lascola, CD; Dewhirst, MW; Spasojevic, I; Benov, L; Batinic-Haberle, I
MLA Citation
Tovmasyan, A, Sampaio, RS, Boss, M-K, Bueno-Janice, JC, Bader, BH, Thomas, M, Reboucas, JS, Orr, M, Chandler, JD, Go, Y-M, Jones, DP, Venkatraman, TN, Haberle, S, Kyui, N, Lascola, CD, Dewhirst, MW, Spasojevic, I, Benov, L, and Batinic-Haberle, I. "Anticancer therapeutic potential of Mn porphyrin/ascorbate system." Free radical biology & medicine 89 (December 2015): 1231-1247.
PMID
26496207
Source
epmc
Published In
Free Radical Biology & Medicine
Volume
89
Publish Date
2015
Start Page
1231
End Page
1247
DOI
10.1016/j.freeradbiomed.2015.10.416

Corrigendum to ‘An educational overview of the chemistry, biochemistry and therapeutic aspects of Mn porphyrins – From superoxide dismutation to H2O2-driven pathways’ [Redox Biology 5C (2015) 43–65]

Authors
Batinic-Haberle, I; Tovmasyan, A; Spasojevic, I
MLA Citation
Batinic-Haberle, I, Tovmasyan, A, and Spasojevic, I. "Corrigendum to ‘An educational overview of the chemistry, biochemistry and therapeutic aspects of Mn porphyrins – From superoxide dismutation to H2O2-driven pathways’ [Redox Biology 5C (2015) 43–65]." Redox Biology 6 (December 2015): 656-656.
Source
crossref
Published In
Redox Biology
Volume
6
Publish Date
2015
Start Page
656
End Page
656
DOI
10.1016/j.redox.2015.09.001

Novel Manganese-Porphyrin Superoxide Dismutase-Mimetic Widens the Therapeutic Margin in a Preclinical Head and Neck Cancer Model.

To test the effects of a novel Mn porphyrin oxidative stress modifier, Mn(III) meso-tetrakis(N-n-butoxyethylpyridinium-2-yl)porphyrin (MnBuOE), for its radioprotective and radiosensitizing properties in normal tissue versus tumor, respectively.Murine oral mucosa and salivary glands were treated with a range of radiation doses with or without MnBuOE to establish the dose-effect curves for mucositis and xerostomia. Radiation injury was quantified by intravital near-infrared imaging of cathepsin activity, assessment of salivation, and histologic analysis. To evaluate effects of MnBuOE on the tumor radiation response, we administered the drug as an adjuvant to fractionated radiation of FaDu xenografts. Again, a range of radiation therapy (RT) doses was administered to establish the radiation dose-effect curve. The 50% tumor control dose values with or without MnBuOE and dose-modifying factor were determined.MnBuOE protected normal tissue by reducing RT-mediated mucositis, xerostomia, and fibrosis. The dose-modifying factor for protection against xerostomia was 0.77. In contrast, MnBuOE increased tumor local control rates compared with controls. The dose-modifying factor, based on the ratio of 50% tumor control dose values, was 1.3. Immunohistochemistry showed that MnBuOE-treated tumors exhibited a significant influx of M1 tumor-associated macrophages, which provides mechanistic insight into its radiosensitizing effects in tumors.MnBuOE widens the therapeutic margin by decreasing the dose of radiation required to control tumor, while increasing normal tissue resistance to RT-mediated injury. This is the first study to quantitatively demonstrate the magnitude of a single drug's ability to radioprotect normal tissue while radiosensitizing tumor.

Authors
Ashcraft, KA; Boss, M-K; Tovmasyan, A; Roy Choudhury, K; Fontanella, AN; Young, KH; Palmer, GM; Birer, SR; Landon, CD; Park, W; Das, SK; Weitner, T; Sheng, H; Warner, DS; Brizel, DM; Spasojevic, I; Batinic-Haberle, I; Dewhirst, MW
MLA Citation
Ashcraft, KA, Boss, M-K, Tovmasyan, A, Roy Choudhury, K, Fontanella, AN, Young, KH, Palmer, GM, Birer, SR, Landon, CD, Park, W, Das, SK, Weitner, T, Sheng, H, Warner, DS, Brizel, DM, Spasojevic, I, Batinic-Haberle, I, and Dewhirst, MW. "Novel Manganese-Porphyrin Superoxide Dismutase-Mimetic Widens the Therapeutic Margin in a Preclinical Head and Neck Cancer Model." International journal of radiation oncology, biology, physics 93.4 (November 2015): 892-900.
PMID
26530759
Source
epmc
Published In
International Journal of Radiation Oncology, Biology, Physics
Volume
93
Issue
4
Publish Date
2015
Start Page
892
End Page
900
DOI
10.1016/j.ijrobp.2015.07.2283

A comprehensive evaluation of catalase-like activity of different classes of redox-active therapeutics.

Because of the increased insight into the biological role of hydrogen peroxide (H2O2) under physiological and pathological conditions and the role it presumably plays in the action of natural and synthetic redox-active drugs, there is a need to accurately define the type and magnitude of reactions that may occur with this intriguing and key species of redoxome. Historically, and frequently incorrectly, the impact of catalase-like activity has been assigned to play a major role in the action of many redox-active drugs, mostly SOD mimics and peroxynitrite scavengers, and in particular MnTBAP(3-) and Mn salen derivatives. The advantage of one redox-active compound over another has often been assigned to the differences in catalase-like activity. Our studies provide substantial evidence that Mn(III) N-alkylpyridylporphyrins couple with H2O2 in actions other than catalase-related. Herein we have assessed the catalase-like activities of different classes of compounds: Mn porphyrins (MnPs), Fe porphyrins (FePs), Mn(III) salen (EUK-8), and Mn(II) cyclic polyamines (SOD-active M40403 and SOD-inactive M40404). Nitroxide (tempol), nitrone (NXY-059), ebselen, and MnCl2, which have not been reported as catalase mimics, were used as negative controls, while catalase enzyme was a positive control. The dismutation of H2O2 to O2 and H2O was followed via measuring oxygen evolved with a Clark oxygen electrode at 25°C. The catalase enzyme was found to have kcat(H2O2)=1.5×10(6)M(-1) s(-1). The yield of dismutation, i.e., the maximal amount of O2 evolved, was assessed also. The magnitude of the yield reflects an interplay between the kcat(H2O2) and the stability of compounds toward H2O2-driven oxidative degradation, and is thus an accurate measure of the efficacy of a catalyst. The kcat(H2O2) values for 12 cationic Mn(III) N-substituted (alkyl and alkoxyalkyl) pyridylporphyrin-based SOD mimics and Mn(III) N,N'-dialkylimidazolium porphyrin, MnTDE-2-ImP(5+), ranged from 23 to 88M(-1) s(-1). The analogous Fe(III) N-alkylpyridylporphyrins showed ~10-fold higher activity than the corresponding MnPs, but the values of kcat(H2O2) are still ~4 orders of magnitude lower than that of the enzyme. While the kcat(H2O2) values for Fe ethyl and n-octyl analogs were 803.5 and 368.4M(-1) s(-1), respectively, the FePs are more prone to H2O2-driven oxidative degradation, therefore allowing for similar yields in H2O2 dismutation as analogous MnPs. The kcat(H2O2) values are dependent on the electron deficiency of the metal site as it controls the peroxide binding in the first step of the dismutation process. SOD-like activities depend on electron deficiency of the metal site also, as it controls the first step of O2(●-) dismutation. In turn, the kcat(O2(●-)) parallels the kcat(H2O2). Therefore, the electron-rich anionic non-SOD mimic MnTBAP(3-) has essentially very low catalase-like activity, kcat(H2O2)=5.8M(-1) s(-1). The catalase-like activities of Mn(III) and Fe(III) porphyrins are at most, 0.0004 and 0.05% of the enzyme activity, respectively. The kcat(H2O2) values of 8.2 and 6.5M(-1) s(-1) were determined for electron-rich Mn(II) cyclic polyamine-based compounds, M40403 and M40404, respectively. The EUK-8, with modest SOD-like activity, has only slightly higher kcat(H2O2)=13.5M(-1) s(-1). The biological relevance of kcat(H2O2) of MnTE-2-PyP(5+), MnTDE-2-ImP(5+), MnTBAP(3-), FeTE-2-PyP(5+), M40403, M40404, and Mn salen was evaluated in wild-type and peroxidase/catalase-deficient E. coli.

Authors
Tovmasyan, A; Maia, CGC; Weitner, T; Carballal, S; Sampaio, RS; Lieb, D; Ghazaryan, R; Ivanovic-Burmazovic, I; Ferrer-Sueta, G; Radi, R; Reboucas, JS; Spasojevic, I; Benov, L; Batinic-Haberle, I
MLA Citation
Tovmasyan, A, Maia, CGC, Weitner, T, Carballal, S, Sampaio, RS, Lieb, D, Ghazaryan, R, Ivanovic-Burmazovic, I, Ferrer-Sueta, G, Radi, R, Reboucas, JS, Spasojevic, I, Benov, L, and Batinic-Haberle, I. "A comprehensive evaluation of catalase-like activity of different classes of redox-active therapeutics." Free radical biology & medicine 86 (September 2015): 308-321.
PMID
26026699
Source
epmc
Published In
Free Radical Biology & Medicine
Volume
86
Publish Date
2015
Start Page
308
End Page
321
DOI
10.1016/j.freeradbiomed.2015.05.018

An educational overview of the chemistry, biochemistry and therapeutic aspects of Mn porphyrins--From superoxide dismutation to H2O2-driven pathways.

Most of the SOD mimics thus far developed belong to the classes of Mn-(MnPs) and Fe porphyrins(FePs), Mn(III) salens, Mn(II) cyclic polyamines and metal salts. Due to their remarkable stability we have predominantly explored Mn porphyrins, aiming initially at mimicking kinetics and thermodynamics of the catalysis of O2(-) dismutation by SOD enzymes. Several MnPs are of potency similar to SOD enzymes. The in vivo bioavailability and toxicity of MnPs have been addressed also. Numerous in vitro and in vivo studies indicate their impressive therapeutic efficacy. Increasing insight into complex cellular redox biology has been accompanied by increasing awareness of complex redox chemistry of MnPs. During O2(-) dismutation process, the most powerful Mn porphyrin-based SOD mimics reduce and oxidize O2(-) with close to identical rate constants. MnPs reduce and oxidize other reactive species also (none of them specific to MnPs), acting as reductants (antioxidant) and pro-oxidants. Distinction must be made between the type of reactions of MnPs and the favorable therapeutic effects we observe; the latter may be of either anti- or pro-oxidative nature. H2O2/MnP mediated oxidation of protein thiols and its impact on cellular transcription seems to dominate redox biology of MnPs. It has been thus far demonstrated that the ability of MnPs to catalyze O2(-) dismutation parallels all other reactivities (such as ONOO(-) reduction) and in turn their therapeutic efficacies. Assuming that all diseases have in common the perturbation of cellular redox environment, developing SOD mimics still seems to be the appropriate strategy for the design of potent redox-active therapeutics.

Authors
Batinic-Haberle, I; Tovmasyan, A; Spasojevic, I
MLA Citation
Batinic-Haberle, I, Tovmasyan, A, and Spasojevic, I. "An educational overview of the chemistry, biochemistry and therapeutic aspects of Mn porphyrins--From superoxide dismutation to H2O2-driven pathways." Redox biology 5 (August 2015): 43-65. (Review)
PMID
25827425
Source
epmc
Published In
Redox Biology
Volume
5
Publish Date
2015
Start Page
43
End Page
65
DOI
10.1016/j.redox.2015.01.017

Manganese (III) meso-tetrakis N-ethylpyridinium-2-yl porphyrin acts as a pro-oxidant to inhibit electron transport chain proteins, modulate bioenergetics, and enhance the response to chemotherapy in lymphoma cells.

The manganese porphyrin, manganese (III) meso-tetrakis N-ethylpyridinium-2-yl porphyrin (MnTE-2-PyP(5+)), acts as a pro-oxidant in the presence of intracellular H2O2. Mitochondria are the most prominent source of intracellular ROS and important regulators of the intrinsic apoptotic pathway. Due to the increased oxidants near and within the mitochondria, we hypothesized that the mitochondria are a target of the pro-oxidative activity of MnTE-2-PyP(5+) and that we could exploit this effect to enhance the chemotherapeutic response in lymphoma. In this study, we demonstrate that MnTE-2-PyP(5+) modulates the mitochondrial redox environment and sensitizes lymphoma cells to antilymphoma chemotherapeutics. MnTE-2-PyP(5+) increased dexamethasone-induced mitochondrial ROS and oxidation of the mitochondrial glutathione pool in lymphoma cells. The combination treatment induced glutathionylation of Complexes I, III, and IV in the electron transport chain, and decreased the activity of Complexes I and III, but not the activity of Complex IV. Treatment with the porphyrin and dexamethasone also decreased cellular ATP levels. Rho(0) malignant T-cells with impaired mitochondrial electron transport chain function were less sensitive to the combination treatment than wild-type cells. These findings suggest that mitochondria are important for the porphyrin's ability to enhance cell death. MnTE-2-PyP(5+) also augmented the effects of 2-deoxy-D-glucose (2DG), an antiglycolytic agent. In combination with 2DG, MnTE-2-PyP(5+) increased protein glutathionylation, decreased ATP levels more than 2DG treatment alone, and enhanced 2DG-induced cell death in primary B-ALL cells. MnTE-2-PyP(5+) did not enhance dexamethasone- or 2DG-induced cell death in normal cells. Our findings suggest that MnTE-2-PyP(5+) has potential as an adjuvant for the treatment of hematologic malignancies.

Authors
Jaramillo, MC; Briehl, MM; Batinic-Haberle, I; Tome, ME
MLA Citation
Jaramillo, MC, Briehl, MM, Batinic-Haberle, I, and Tome, ME. "Manganese (III) meso-tetrakis N-ethylpyridinium-2-yl porphyrin acts as a pro-oxidant to inhibit electron transport chain proteins, modulate bioenergetics, and enhance the response to chemotherapy in lymphoma cells." Free radical biology & medicine 83 (June 2015): 89-100.
PMID
25725417
Source
epmc
Published In
Free Radical Biology & Medicine
Volume
83
Publish Date
2015
Start Page
89
End Page
100
DOI
10.1016/j.freeradbiomed.2015.01.031

RADIOPROTECTION OF ERECTILE FUNCTION USING NOVEL ANTI-OXIDANT IN THE RAT

Authors
Granieri, M; Tovmasyan, A; Yan, H; Lu, X; Mao, L; Macias, E; Spasojevic, I; Batinic-Haberle, I; Peterson, AC; Koontz, BF
MLA Citation
Granieri, M, Tovmasyan, A, Yan, H, Lu, X, Mao, L, Macias, E, Spasojevic, I, Batinic-Haberle, I, Peterson, AC, and Koontz, BF. "RADIOPROTECTION OF ERECTILE FUNCTION USING NOVEL ANTI-OXIDANT IN THE RAT." May 2015.
Source
wos-lite
Published In
The Journal of Sexual Medicine
Volume
12
Publish Date
2015
Start Page
178
End Page
179

Radioprotection of the brain white matter by Mn(III) n-Butoxyethylpyridylporphyrin-based superoxide dismutase mimic MnTnBuOE-2-PyP5+.

Cranial irradiation is a standard therapy for primary and metastatic brain tumors. A major drawback of radiotherapy (RT), however, is long-term cognitive loss that affects quality of life. Radiation-induced oxidative stress in normal brain tissue is thought to contribute to cognitive decline. We evaluated the effectiveness of a novel mimic of superoxide dismutase enzyme (SOD), MnTnBuOE-2-PyP(5+)(Mn(III) meso-tetrakis(N-n-butoxyethylpyridinium-2-yl)porphyrin), to provide long-term neuroprotection following 8 Gy of whole brain irradiation. Long-term RT damage can only be assessed by brain imaging and neurocognitive studies. C57BL/6J mice were treated with MnTnBuOE-2-PyP(5+) before and after RT and evaluated three months later. At this time point, drug concentration in the brain was 25 nmol/L. Mice treated with MnTnBuOE-2-PyP(5+)/RT exhibited MRI evidence for myelin preservation in the corpus callosum compared with saline/RT treatment. Corpus callosum histology demonstrated a significant loss of axons in the saline/RT group that was rescued in the MnTnBuOE-2-PyP(5+)/RT group. In addition, the saline/RT groups exhibited deficits in motor proficiency as assessed by the rotorod test and running wheel tests. These deficits were ameliorated in groups treated with MnTnBuOE-2-PyP(5+)/RT. Our data demonstrate that MnTnBuOE-2-PyP(5+) is neuroprotective for oxidative stress damage caused by radiation exposure. In addition, glioblastoma cells were not protected by MnTnBuOE-2-PyP(5+) combination with radiation in vitro. Likewise, the combination of MnTnBuOE-2-PyP(5+) with radiation inhibited tumor growth more than RT alone in flank tumors. In summary, MnTnBuOE-2-PyP(5+) has dual activity as a neuroprotector and a tumor radiosensitizer. Thus, it is an attractive candidate for adjuvant therapy with RT in future studies with patients with brain cancer.

Authors
Weitzel, DH; Tovmasyan, A; Ashcraft, KA; Rajic, Z; Weitner, T; Liu, C; Li, W; Buckley, AF; Prasad, MR; Young, KH; Rodriguiz, RM; Wetsel, WC; Peters, KB; Spasojevic, I; Herndon, JE; Batinic-Haberle, I; Dewhirst, MW
MLA Citation
Weitzel, DH, Tovmasyan, A, Ashcraft, KA, Rajic, Z, Weitner, T, Liu, C, Li, W, Buckley, AF, Prasad, MR, Young, KH, Rodriguiz, RM, Wetsel, WC, Peters, KB, Spasojevic, I, Herndon, JE, Batinic-Haberle, I, and Dewhirst, MW. "Radioprotection of the brain white matter by Mn(III) n-Butoxyethylpyridylporphyrin-based superoxide dismutase mimic MnTnBuOE-2-PyP5+." Molecular cancer therapeutics 14.1 (January 2015): 70-79.
PMID
25319393
Source
epmc
Published In
Molecular cancer therapeutics
Volume
14
Issue
1
Publish Date
2015
Start Page
70
End Page
79
DOI
10.1158/1535-7163.mct-14-0343

Amphiphilic cationic Zn-porphyrins with high photodynamic antimicrobial activity.

Photodynamic inactivation of microbes can efficiently eradicate antibiotic-resistant strains. Systematic structural modification was used to investigate how porphyrin-based photosensitizers (PSs) could be designed for improved antibacterial activity.Zinc(II)5,10,15,20-tetrakis(N-alkylpyridinium-2(3,4)-yl)porphyrins presenting systematic modifications at the periphery of the porphyrin ring were evaluated for toxicity and antimicrobial photodynamic activity by measuring metabolic activity, cell membrane integrity and viability using antibiotic-sensitive and resistant Escherichia coli strains as model Gram-negative targets.Maximal sensitizer uptake, and, upon illumination, decrease of viable bacteria by >6 log10 were achieved by positively charged amphiphilic PSs with longer (six to eight carbon) alkyl substituents.Antibacterial photoefficiency (throughout the text photoefficiency has been used as equivalent of photocytotoxic efficacy) can be increased by orders of magnitude by increasing the lipophilicity of cationic alkylmetalloporphyrin PSs.

Authors
Thomas, M; Craik, JD; Tovmasyan, A; Batinic-Haberle, I; Benov, LT
MLA Citation
Thomas, M, Craik, JD, Tovmasyan, A, Batinic-Haberle, I, and Benov, LT. "Amphiphilic cationic Zn-porphyrins with high photodynamic antimicrobial activity." Future microbiology 10.5 (January 2015): 709-724.
PMID
26000647
Source
epmc
Published In
Future microbiology
Volume
10
Issue
5
Publish Date
2015
Start Page
709
End Page
724
DOI
10.2217/fmb.14.148

Mn porphyrin-based SOD mimic, MnTnHex-2-PyP(5+), and non-SOD mimic, MnTBAP(3-), suppressed rat spinal cord ischemia/reperfusion injury via NF-κB pathways.

Herein we have demonstrated that both superoxide dismutase (SOD) mimic, cationic Mn(III) meso-tetrakis(N-n-hexylpyridinium-2-yl)porphyrin (MnTnHex-2-PyP(5+)), and non-SOD mimic, anionic Mn(III) meso-tetrakis(4-carboxylatophenyl)porphyrin (MnTBAP(3-)), protect against oxidative stress caused by spinal cord ischemia/reperfusion via suppression of nuclear factor kappa B (NF-κB) pro-inflammatory pathways. Earlier reports showed that Mn(III) N-alkylpyridylporphyrins were able to prevent the DNA binding of NF-κB in an aqueous system, whereas MnTBAP(3-) was not. Here, for the first time, in a complex in vivo system-animal model of spinal cord injury-a similar impact of MnTBAP(3-), at a dose identical to that of MnTnHex-2-PyP(5+), was demonstrated in NF-κB downregulation. Rats were treated subcutaneously at 1.5 mg/kg starting at 30 min before ischemia/reperfusion, and then every 12 h afterward for either 48 h or 7 days. The anti-inflammatory effects of both Mn porphyrins (MnPs) were demonstrated in the spinal cord tissue at both 48 h and 7 days. The downregulation of NF-κB, a major pro-inflammatory signaling protein regulating astrocyte activation, was detected and found to correlate well with the suppression of astrogliosis (as glial fibrillary acidic protein) by both MnPs. The markers of oxidative stress, lipid peroxidation and protein carbonyl formation, were significantly reduced by MnPs. The favorable impact of both MnPs on motor neurons (Tarlov score and inclined plane test) was assessed. No major changes in glutathione peroxidase- and SOD-like activities were demonstrated, which implies that none of the MnPs acted as SOD mimic. Increasing amount of data on the reactivity of MnTBAP(3-) with reactive nitrogen species (RNS) (.NO/HNO/ONOO(-)) suggests that RNS/MnTBAP(3-)-driven modification of NF-κB protein cysteines may be involved in its therapeutic effects. This differs from the therapeutic efficacy of MnTnHex-2-PyP(5+) which presumably occurs via reactive oxygen species and relates to NF-κB thiol oxidation; the role of RNS cannot be excluded.

Authors
Celic, T; Španjol, J; Bobinac, M; Tovmasyan, A; Vukelic, I; Reboucas, JS; Batinic-Haberle, I; Bobinac, D
MLA Citation
Celic, T, Španjol, J, Bobinac, M, Tovmasyan, A, Vukelic, I, Reboucas, JS, Batinic-Haberle, I, and Bobinac, D. "Mn porphyrin-based SOD mimic, MnTnHex-2-PyP(5+), and non-SOD mimic, MnTBAP(3-), suppressed rat spinal cord ischemia/reperfusion injury via NF-κB pathways." Free radical research 48.12 (December 2014): 1426-1442.
PMID
25185063
Source
epmc
Published In
Free Radical Research (Informa)
Volume
48
Issue
12
Publish Date
2014
Start Page
1426
End Page
1442
DOI
10.3109/10715762.2014.960865

Rational design of superoxide dismutase (SOD) mimics: the evaluation of the therapeutic potential of new cationic Mn porphyrins with linear and cyclic substituents.

Our goal herein has been to gain further insight into the parameters which control porphyrin therapeutic potential. Mn porphyrins (MnTnOct-2-PyP(5+), MnTnHexOE-2-PyP(5+), MnTE-2-PyPhP(5+), and MnTPhE-2-PyP(5+)) that bear the same positive charge and same number of carbon atoms at meso positions of porphyrin core were explored. The carbon atoms of their meso substituents are organized to form either linear or cyclic structures of vastly different redox properties, bulkiness, and lipophilicities. These Mn porphyrins were compared to frequently studied compounds, MnTE-2-PyP(5+), MnTE-3-PyP(5+), and MnTBAP(3-). All Mn(III) porphyrins (MnPs) have metal-centered reduction potential, E1/2 for Mn(III)P/Mn(II)P redox couple, ranging from -194 to +340 mV versus NHE, log kcat(O2(•-)) from 3.16 to 7.92, and log kred(ONOO(-)) from 5.02 to 7.53. The lipophilicity, expressed as partition between n-octanol and water, log POW, was in the range -1.67 to -7.67. The therapeutic potential of MnPs was assessed via: (i) in vitro ability to prevent spontaneous lipid peroxidation in rat brain homogenate as assessed by malondialdehyde levels; (ii) in vivo O2(•-) specific assay to measure the efficacy in protecting the aerobic growth of SOD-deficient Saccharomyces cerevisiae; and (iii) aqueous solution chemistry to measure the reactivity toward major in vivo endogenous antioxidant, ascorbate. Under the conditions of lipid peroxidation assay, the transport across the cellular membranes, and in turn shape and size of molecule, played no significant role. Those MnPs of E1/2 ∼ +300 mV were the most efficacious, significantly inhibiting lipid peroxidation in 0.5-10 μM range. At up to 200 μM, MnTBAP(3-) (E1/2 = -194 mV vs NHE) failed to inhibit lipid peroxidation, while MnTE-2-PyPhP(5+) with 129 mV more positive E1/2 (-65 mV vs NHE) was fully efficacious at 50 μM. The E1/2 of Mn(III)P/Mn(II)P redox couple is proportional to the log kcat(O2(•-)), i.e., the SOD-like activity of MnPs. It is further proportional to kred(ONOO(-)) and the ability of MnPs to prevent lipid peroxidation. In turn, the inhibition of lipid peroxidation by MnPs is also proportional to their SOD-like activity. In an in vivo S. cerevisiae assay, however, while E1/2 predominates, lipophilicity significantly affects the efficacy of MnPs. MnPs of similar log POW and E1/2, that have linear alkyl or alkoxyalkyl pyridyl substituents, distribute more easily within a cell and in turn provide higher protection to S. cerevisiae in comparison to MnP with bulky cyclic substituents. The bell-shape curve, with MnTE-2-PyP(5+) exhibiting the highest ability to catalyze ascorbate oxidation, has been established and discussed. Our data support the notion that the SOD-like activity of MnPs parallels their therapeutic potential, though species other than O2(•-), such as peroxynitrite, H2O2, lipid reactive species, and cellular reductants, may be involved in their mode(s) of action(s).

Authors
Tovmasyan, A; Carballal, S; Ghazaryan, R; Melikyan, L; Weitner, T; Maia, CGC; Reboucas, JS; Radi, R; Spasojevic, I; Benov, L; Batinic-Haberle, I
MLA Citation
Tovmasyan, A, Carballal, S, Ghazaryan, R, Melikyan, L, Weitner, T, Maia, CGC, Reboucas, JS, Radi, R, Spasojevic, I, Benov, L, and Batinic-Haberle, I. "Rational design of superoxide dismutase (SOD) mimics: the evaluation of the therapeutic potential of new cationic Mn porphyrins with linear and cyclic substituents." Inorganic chemistry 53.21 (November 2014): 11467-11483.
PMID
25333724
Source
epmc
Published In
Inorganic Chemistry
Volume
53
Issue
21
Publish Date
2014
Start Page
11467
End Page
11483
DOI
10.1021/ic501329p

Mitigation of Radiation-Mediated Suppression of Hippocampal Neurogenesis

Authors
Yang, P; Leu, D; Yang, H; Khosrav, M; Tovmasyan, A; Spasojevic, I; Batinic-Haberle, I; Huang, T-T
MLA Citation
Yang, P, Leu, D, Yang, H, Khosrav, M, Tovmasyan, A, Spasojevic, I, Batinic-Haberle, I, and Huang, T-T. "Mitigation of Radiation-Mediated Suppression of Hippocampal Neurogenesis." Free Radical Biology and Medicine 76 (November 2014): S97-S97.
Source
crossref
Published In
Free Radical Biology & Medicine
Volume
76
Publish Date
2014
Start Page
S97
End Page
S97
DOI
10.1016/j.freeradbiomed.2014.10.335

Rational Design of New Cationic Mn Porphyrins and Evaluation of Their Therapeutic Potential

Authors
Tovmasyan, A; Carballal, S; Ghazaryan, R; Melikyan, L; Weitner, T; Maia, CGC; Reboucas, JS; Radi, R; Spasojevic, I; Benov, L; Batinic-Haberle, I
MLA Citation
Tovmasyan, A, Carballal, S, Ghazaryan, R, Melikyan, L, Weitner, T, Maia, CGC, Reboucas, JS, Radi, R, Spasojevic, I, Benov, L, and Batinic-Haberle, I. "Rational Design of New Cationic Mn Porphyrins and Evaluation of Their Therapeutic Potential." Free Radical Biology and Medicine 76 (November 2014): S94-S94.
Source
crossref
Published In
Free Radical Biology & Medicine
Volume
76
Publish Date
2014
Start Page
S94
End Page
S94
DOI
10.1016/j.freeradbiomed.2014.10.326

Mn Porphyrin-Based SOD Mimic, MnTnHex-2-PyP5+ and Non-SOD Mimic, MnTBAP3- suppresed Rat Spinal Cord Ischemia/reperfusion Injury via NF-κB Pathways

Authors
Vukelic, I; Celic, T; Spanjol, J; Bobinac, M; Tovmasyan, A; Santos Reboucas, J; Batinic-Haberle, I; Bobinac, D
MLA Citation
Vukelic, I, Celic, T, Spanjol, J, Bobinac, M, Tovmasyan, A, Santos Reboucas, J, Batinic-Haberle, I, and Bobinac, D. "Mn Porphyrin-Based SOD Mimic, MnTnHex-2-PyP5+ and Non-SOD Mimic, MnTBAP3- suppresed Rat Spinal Cord Ischemia/reperfusion Injury via NF-κB Pathways." Free Radical Biology and Medicine 76 (November 2014): S95-S95.
Source
crossref
Published In
Free Radical Biology & Medicine
Volume
76
Publish Date
2014
Start Page
S95
End Page
S95
DOI
10.1016/j.freeradbiomed.2014.10.329

A Comprehensive Study of the Catalase Activity of Different Classes of Experimental Therapeutics Commonly Used as Redox Modulators

Authors
Maia, CGC; Tovmasyan, A; Weitner, T; Lieb, D; Ivanovic-Burmazovic, I; Reboucas, JS; Batinic-Haberle, I
MLA Citation
Maia, CGC, Tovmasyan, A, Weitner, T, Lieb, D, Ivanovic-Burmazovic, I, Reboucas, JS, and Batinic-Haberle, I. "A Comprehensive Study of the Catalase Activity of Different Classes of Experimental Therapeutics Commonly Used as Redox Modulators." Free Radical Biology and Medicine 76 (November 2014): S85-S86.
Source
crossref
Published In
Free Radical Biology & Medicine
Volume
76
Publish Date
2014
Start Page
S85
End Page
S86
DOI
10.1016/j.freeradbiomed.2014.10.301

The Role of Ascorbate in Therapeutic Actions of Cationic Mn Porphyrin-Based SOD Mimics

Authors
Tovmasyan, A; Roberts, ERH; Yuliana, Y; Haberle, S; Boss, M-K; Venkatraman, TN; Lascola, C; Dewhirst, MW; Lam, PYP; Benov, L; Leong, KW; Batinic-Haberle, I
MLA Citation
Tovmasyan, A, Roberts, ERH, Yuliana, Y, Haberle, S, Boss, M-K, Venkatraman, TN, Lascola, C, Dewhirst, MW, Lam, PYP, Benov, L, Leong, KW, and Batinic-Haberle, I. "The Role of Ascorbate in Therapeutic Actions of Cationic Mn Porphyrin-Based SOD Mimics." Free Radical Biology and Medicine 76 (November 2014): S94-S95.
Source
crossref
Published In
Free Radical Biology & Medicine
Volume
76
Publish Date
2014
Start Page
S94
End Page
S95
DOI
10.1016/j.freeradbiomed.2014.10.327

Redox potential determines the reaction mechanism of HNO donors with Mn and Fe porphyrins: defining the better traps.

Azanone ((1)HNO, nitroxyl) is a highly reactive molecule with interesting chemical and biological properties. Like nitric oxide (NO), its main biologically related targets are oxygen, thiols, and metalloproteins, particularly heme proteins. As HNO dimerizes with a rate constant between 10(6) and 10(7) M(-1) s(-1), reactive studies are performed using donors, which are compounds that spontaneously release HNO in solution. In the present work, we studied the reaction mechanism and kinetics of two azanone donors Angelís Salt and toluene sulfohydroxamic acid (TSHA) with eight different Mn porphyrins as trapping agents. These porphyrins differ in their total peripheral charge (positively or negatively charged) and in their Mn(III)/Mn(II) reduction potential, showing for each case positive (oxidizing) and negative (reducing) values. Our results show that the reduction potential determines the azanone donor reaction mechanism. While oxidizing porphyrins accelerate decomposition of the donor, reducing porphyrins react with free HNO. Our results also shed light into the donor decomposition mechanism using ab initio methods and provide a thorough analysis of which MnP are the best candidates for azanone trapping and quantification experiments.

Authors
Alvarez, L; Suarez, SA; Bikiel, DE; Reboucas, JS; Batinić-Haberle, I; Martí, MA; Doctorovich, F
MLA Citation
Alvarez, L, Suarez, SA, Bikiel, DE, Reboucas, JS, Batinić-Haberle, I, Martí, MA, and Doctorovich, F. "Redox potential determines the reaction mechanism of HNO donors with Mn and Fe porphyrins: defining the better traps." Inorganic chemistry 53.14 (July 8, 2014): 7351-7360.
PMID
25001488
Source
epmc
Published In
Inorganic Chemistry
Volume
53
Issue
14
Publish Date
2014
Start Page
7351
End Page
7360
DOI
10.1021/ic5007082

Redox proteomic identification of HNE-bound mitochondrial proteins in cardiac tissues reveals a systemic effect on energy metabolism after doxorubicin treatment.

Doxorubicin (DOX), one of the most effective anticancer drugs, is known to generate progressive cardiac damage, which is due, in part, to DOX-induced reactive oxygen species (ROS). The elevated ROS often induce oxidative protein modifications that result in alteration of protein functions. This study demonstrates that the level of proteins adducted by 4-hydroxy-2-nonenal (HNE), a lipid peroxidation product, is significantly increased in mouse heart mitochondria after DOX treatment. A redox proteomics method involving two-dimensional electrophoresis followed by mass spectrometry and investigation of protein databases identified several HNE-modified mitochondrial proteins, which were verified by HNE-specific immunoprecipitation in cardiac mitochondria from the DOX-treated mice. The majority of the identified proteins are related to mitochondrial energy metabolism. These include proteins in the citric acid cycle and electron transport chain. The enzymatic activities of the HNE-adducted proteins were significantly reduced in DOX-treated mice. Consistent with the decline in the function of the HNE-adducted proteins, the respiratory function of cardiac mitochondria as determined by oxygen consumption rate was also significantly reduced after DOX treatment. Treatment with Mn(III) meso-tetrakis(N-n-butoxyethylpyridinium-2-yl)porphyrin, an SOD mimic, averted the doxorubicin-induced mitochondrial dysfunctions as well as the HNE-protein adductions. Together, the results demonstrate that free radical-mediated alteration of energy metabolism is an important mechanism mediating DOX-induced cardiac injury, suggesting that metabolic intervention may represent a novel approach to preventing cardiac injury after chemotherapy.

Authors
Zhao, Y; Miriyala, S; Miao, L; Mitov, M; Schnell, D; Dhar, SK; Cai, J; Klein, JB; Sultana, R; Butterfield, DA; Vore, M; Batinic-Haberle, I; Bondada, S; St Clair, DK
MLA Citation
Zhao, Y, Miriyala, S, Miao, L, Mitov, M, Schnell, D, Dhar, SK, Cai, J, Klein, JB, Sultana, R, Butterfield, DA, Vore, M, Batinic-Haberle, I, Bondada, S, and St Clair, DK. "Redox proteomic identification of HNE-bound mitochondrial proteins in cardiac tissues reveals a systemic effect on energy metabolism after doxorubicin treatment." Free radical biology & medicine 72 (July 2014): 55-65.
PMID
24632380
Source
epmc
Published In
Free Radical Biology & Medicine
Volume
72
Publish Date
2014
Start Page
55
End Page
65
DOI
10.1016/j.freeradbiomed.2014.03.001

Manganese superoxide dismutase-mediated inside-out signaling in HaCaT human keratinocytes and SKH-1 mouse skin.

Inside-out signaling occurs when changes in organellar activity lead to alterations in cell signaling that culminate at the cell surface. Mitochondria are vital signaling platforms in cells that participate in radiation-induced inside-out signaling. However, the importance of the reactive oxygen species (ROS)-scavenging ability of mitochondria through manganese superoxide dismutase (MnSOD) is not established. Here, we used MnSOD heterozygous knockout and transgenic SKH-1 hairless, albino mice and MnSOD knockdown and overexpressing HaCaT human keratinocytes to study the effects of MnSOD on ultraviolet (UV) radiation-induced inside-out signaling.There is an inverse correlation between MnSOD expression and UV-induced activation of epidermal growth factor receptor (EGFR), as determined by phosphorylation at Tyr1068, both in vitro and in vivo, which correlates with increased ROS production (as measured by dihydroethidium fluorescence). EGFR activation is dependent on Nox4 expression and Src kinase activation, with Src activation upstream of Nox4 in regulation of EGFR activation. Enhanced EGFR activation in MnSOD knockdown cells is abrogated by treatment with the SOD mimetic MnTnBuOE-2-PyP(5+).Our data demonstrate that the ROS-scavenging ability of mitochondria, through the expression of MnSOD, is important for UV-induced inside-out signaling. Decreased MnSOD expression enhances UV-induced activation of different oncogenic signaling pathways through an inside-out signaling-mediated mechanism. Inhibition of inside-out signaling by MnTnBuOE-2-PyP(5+) mimics the effect of endogenous MnSOD, suggesting that pharmacological intervention by SOD mimetics could play an important role in the prevention of aberrant cell signaling, which may contribute to carcinogenesis and may prove valuable for the treatment or prevention of cancer in the future.

Authors
Holley, AK; Xu, Y; Noel, T; Bakthavatchalu, V; Batinic-Haberle, I; St Clair, DK
MLA Citation
Holley, AK, Xu, Y, Noel, T, Bakthavatchalu, V, Batinic-Haberle, I, and St Clair, DK. "Manganese superoxide dismutase-mediated inside-out signaling in HaCaT human keratinocytes and SKH-1 mouse skin." Antioxidants & redox signaling 20.15 (May 2014): 2347-2360.
PMID
24635018
Source
epmc
Published In
Antioxidants & Redox Signaling
Volume
20
Issue
15
Publish Date
2014
Start Page
2347
End Page
2360
DOI
10.1089/ars.2013.5204

Complex chemistry and biology of redox-active compounds, commonly known as SOD mimics, affect their therapeutic effects.

This Editorial has the intention to stress the complex chemistry and biology of redox-active compounds, regarded as SOD mimics. It further aims to caution the researchers of the importance of being up-to-date with the present knowledge on such compounds and their cellular redox biology when coming up with their conclusions, based on the particular species involved in their studies.

Authors
Batinic-Haberle, I; Spasojevic, I
MLA Citation
Batinic-Haberle, I, and Spasojevic, I. "Complex chemistry and biology of redox-active compounds, commonly known as SOD mimics, affect their therapeutic effects." Antioxidants & redox signaling 20.15 (May 2014): 2323-2325.
PMID
24650329
Source
epmc
Published In
Antioxidants & Redox Signaling
Volume
20
Issue
15
Publish Date
2014
Start Page
2323
End Page
2325
DOI
10.1089/ars.2014.5921

Manganese-based superoxide dismutase mimics modify both acute and long-term outcome severity in a Drosophila melanogaster model of classic galactosemia.

The goal of this study was to use two manganese (Mn)-based superoxide dismutase (SOD) mimics to test the hypothesis that reactive oxygen species contribute to both acute and long-term outcomes in a galactose-1P uridylyltransferase (GALT)-null Drosophila melanogaster model of classic galactosemia.We tested the impact of each of two Mn porphyrin SOD mimics, MnTnBuOE-2-PyP(5+), and MnTE-2-PyP(5+), (i) on survival of GALT-null Drosophila larvae reared in the presence versus absence of dietary galactose and (ii) on the severity of a long-term movement defect in GALT-null adult flies. Both SOD mimics conferred a significant survival benefit to GALT-null larvae exposed to galactose but not to controls or to GALT-null larvae reared in the absence of galactose. One mimic, MnTE-2-PyP(5+), also largely rescued a galactose-independent long-term movement defect otherwise seen in adult GALT-null flies. The survival benefit of both SOD mimics occurred despite continued accumulation of elevated galactose-1P in the treated animals, and studies of thiolated proteins demonstrated that in both the presence and absence of dietary galactose MnTE-2-PyP(5+) largely prevented the elevated protein oxidative damage otherwise seen in GALT-null animals relative to controls.Our results confirm oxidative stress as a mediator of acute galactose sensitivity in GALT-null Drosophila larvae and demonstrate for the first time that oxidative stress may also contribute to galactose-independent adult outcomes in GALT deficiency. Finally, our results demonstrate for the first time that both MnTnBuOE-2-PyP(5+) and MnTE-2-PyP(5+) are bioavailable and effective when administered through an oral route in a D. melanogaster model of classic galactosemia.

Authors
Jumbo-Lucioni, PP; Ryan, EL; Hopson, ML; Bishop, HM; Weitner, T; Tovmasyan, A; Spasojevic, I; Batinic-Haberle, I; Liang, Y; Jones, DP; Fridovich-Keil, JL
MLA Citation
Jumbo-Lucioni, PP, Ryan, EL, Hopson, ML, Bishop, HM, Weitner, T, Tovmasyan, A, Spasojevic, I, Batinic-Haberle, I, Liang, Y, Jones, DP, and Fridovich-Keil, JL. "Manganese-based superoxide dismutase mimics modify both acute and long-term outcome severity in a Drosophila melanogaster model of classic galactosemia." Antioxidants & redox signaling 20.15 (May 2014): 2361-2371.
PMID
23758052
Source
epmc
Published In
Antioxidants & Redox Signaling
Volume
20
Issue
15
Publish Date
2014
Start Page
2361
End Page
2371
DOI
10.1089/ars.2012.5122

SOD therapeutics: latest insights into their structure-activity relationships and impact on the cellular redox-based signaling pathways.

Superoxide dismutase (SOD) enzymes are indispensable and ubiquitous antioxidant defenses maintaining the steady-state levels of O2·(-); no wonder, thus, that their mimics are remarkably efficacious in essentially any animal model of oxidative stress injuries thus far explored.Structure-activity relationship (half-wave reduction potential [E1/2] versus log kcat), originally reported for Mn porphyrins (MnPs), is valid for any other class of SOD mimics, as it is dominated by the superoxide reduction and oxidation potential. The biocompatible E1/2 of ∼+300 mV versus normal hydrogen electrode (NHE) allows powerful SOD mimics as mild oxidants and antioxidants (alike O2·(-)) to readily traffic electrons among reactive species and signaling proteins, serving as fine mediators of redox-based signaling pathways. Based on similar thermodynamics, both SOD enzymes and their mimics undergo similar reactions, however, due to vastly different sterics, with different rate constants.Although log kcat(O2·(-)) is a good measure of therapeutic potential of SOD mimics, discussions of their in vivo mechanisms of actions remain mostly of speculative character. Most recently, the therapeutic and mechanistic relevance of oxidation of ascorbate and glutathionylation and oxidation of protein thiols by MnP-based SOD mimics and subsequent inactivation of nuclear factor κB has been substantiated in rescuing normal and killing cancer cells. Interaction of MnPs with thiols seems to be, at least in part, involved in up-regulation of endogenous antioxidative defenses, leading to the healing of diseased cells.Mechanistic explorations of single and combined therapeutic strategies, along with studies of bioavailability and translational aspects, will comprise future work in optimizing redox-active drugs.

Authors
Batinic-Haberle, I; Tovmasyan, A; Roberts, ERH; Vujaskovic, Z; Leong, KW; Spasojevic, I
MLA Citation
Batinic-Haberle, I, Tovmasyan, A, Roberts, ERH, Vujaskovic, Z, Leong, KW, and Spasojevic, I. "SOD therapeutics: latest insights into their structure-activity relationships and impact on the cellular redox-based signaling pathways." Antioxidants & redox signaling 20.15 (May 2014): 2372-2415. (Review)
PMID
23875805
Source
epmc
Published In
Antioxidants & Redox Signaling
Volume
20
Issue
15
Publish Date
2014
Start Page
2372
End Page
2415
DOI
10.1089/ars.2012.5147

Erratum: Peroxynitrite formation in nitric oxide-exposed submitochondrial particles: Detection, oxidative damage and catalytic removal by Mn-porphyrins (Archives of Biochemistry and Biophysics (2013) 529 (45-54))

Authors
Valez, V; Cassina, A; Batinic-Haberle, I; Kalyanaraman, B; Ferrer-Sueta, G; Radi, R
MLA Citation
Valez, V, Cassina, A, Batinic-Haberle, I, Kalyanaraman, B, Ferrer-Sueta, G, and Radi, R. "Erratum: Peroxynitrite formation in nitric oxide-exposed submitochondrial particles: Detection, oxidative damage and catalytic removal by Mn-porphyrins (Archives of Biochemistry and Biophysics (2013) 529 (45-54))." Archives of Biochemistry and Biophysics 547 (April 1, 2014): 44-.
Source
scopus
Published In
Archives of Biochemistry and Biophysics
Volume
547
Publish Date
2014
Start Page
44
DOI
10.1016/j.abb.2014.02.004

Corrigendum to: Peroxynitrite formation in nitric oxide-exposed submitochondrial particles: Detection, oxidative damage and catalytic removal by Mn–porphyrins [Arch. Biochem. Biophys. 529 (2013) 45–54]

Authors
Valez, V; Cassina, A; Batinic-Haberle, I; Kalyanaraman, B; Ferrer-Sueta, G; Radi, R
MLA Citation
Valez, V, Cassina, A, Batinic-Haberle, I, Kalyanaraman, B, Ferrer-Sueta, G, and Radi, R. "Corrigendum to: Peroxynitrite formation in nitric oxide-exposed submitochondrial particles: Detection, oxidative damage and catalytic removal by Mn–porphyrins [Arch. Biochem. Biophys. 529 (2013) 45–54]." Archives of Biochemistry and Biophysics 547 (April 2014): 44-44.
Source
crossref
Published In
Archives of Biochemistry and Biophysics
Volume
547
Publish Date
2014
Start Page
44
End Page
44
DOI
10.1016/j.abb.2014.02.004

Mn porphyrin in combination with ascorbate acts as a pro-oxidant and mediates caspase-independent cancer cell death.

Resistance to therapy-mediated apoptosis in inflammatory breast cancer, an aggressive and distinct subtype of breast cancer, was recently attributed to increased superoxide dismutase (SOD) expression, glutathione (GSH) content, and decreased accumulation of reactive species. In this study, we demonstrate the unique ability of two Mn(III) N-substituted pyridylporphyrin (MnP)-based SOD mimics (MnTE-2-PyP(5+) and MnTnBuOE-2-PyP(5+)) to catalyze oxidation of ascorbate, leading to the production of excessive levels of peroxide, and in turn cell death. The accumulation of peroxide, as a consequence of MnP+ascorbate treatment, was fully reversed by the administration of exogenous catalase, showing that hydrogen peroxide is essential for cell death. Cell death as a consequence of the action of MnP+ascorbate corresponded to decreases in GSH levels, prosurvival signaling (p-NF-κB, p-ERK1/2), and in expression of X-linked inhibitor of apoptosis protein, the most potent caspase inhibitor. Although markers of classical apoptosis were observed, including PARP cleavage and annexin V staining, administration of a pan-caspase inhibitor, Q-VD-OPh, did not reverse the observed cytotoxicity. MnP+ascorbate-treated cells showed nuclear translocation of apoptosis-inducing factor, suggesting the possibility of a mechanism of caspase-independent cell death. Pharmacological ascorbate has already shown promise in recently completed phase I clinical trials, in which its oxidation and subsequent peroxide formation was catalyzed by endogenous metalloproteins. The catalysis of ascorbate oxidation by an optimized metal-based catalyst (such as MnP) carries a large therapeutic potential as an anticancer agent by itself or in combination with other modalities such as radio- and chemotherapy.

Authors
Evans, MK; Tovmasyan, A; Batinic-Haberle, I; Devi, GR
MLA Citation
Evans, MK, Tovmasyan, A, Batinic-Haberle, I, and Devi, GR. "Mn porphyrin in combination with ascorbate acts as a pro-oxidant and mediates caspase-independent cancer cell death." Free Radic Biol Med 68 (March 2014): 302-314.
PMID
24334253
Source
pubmed
Published In
Free Radical Biology and Medicine
Volume
68
Publish Date
2014
Start Page
302
End Page
314
DOI
10.1016/j.freeradbiomed.2013.11.031

Robust rat pulmonary radioprotection by a lipophilic Mn N-alkylpyridylporphyrin, MnTnHex-2-PyP(5+).

With the goal to enhance the distribution of cationic Mn porphyrins within mitochondria, the lipophilic Mn(III)meso-tetrakis(N-n-hexylpyridinium-2-yl)porphyrin, MnTnHex-2-PyP(5+) has been synthesized and tested in several different model of diseases, where it shows remarkable efficacy at as low as 50 µg/kg single or multiple doses. Yet, in a rat lung radioprotection study, at higher 0.6-1 mg/kg doses, due to its high accumulation and micellar character, it became toxic. To avoid the toxicity, herein the pulmonary radioprotection of MnTnHex-2-PyP(5+) was assessed at 50 µg/kg. Fischer rats were irradiated to their right hemithorax (28 Gy) and treated with 0.05 mg/kg/day of MnTnHex-2-PyP(5+) for 2 weeks by subcutaneously-implanted osmotic pumps, starting at 2 h post-radiation. The body weights and breathing frequencies were followed for 10 weeks post-radiation, when the histopathology and immunohistochemistry were assessed. Impact of MnTnHex-2-PyP(5+) on macrophage recruitment (ED-1), DNA oxidative damage (8-OHdG), TGF-β1, VEGF(A) and HIF-1α were measured. MnTnHex-2-PyP(5+) significantly decreased radiation-induced lung histopathological (H&E staining) and functional damage (breathing frequencies), suppressed oxidative stress directly (8-OHdG), or indirectly, affecting TGF-β1, VEGF (A) and HIF-1α pathways. The magnitude of the therapeutic effects is similar to the effects demonstrated under same experimental conditions with 120-fold higher dose of ~5000-fold less lipophilic Mn(III)meso-tetrakis(N-ethylpyridinium-2-yl)porphyrin, MnTE-2-PyP(5+).

Authors
Gauter-Fleckenstein, B; Reboucas, JS; Fleckenstein, K; Tovmasyan, A; Owzar, K; Jiang, C; Batinic-Haberle, I; Vujaskovic, Z
MLA Citation
Gauter-Fleckenstein, B, Reboucas, JS, Fleckenstein, K, Tovmasyan, A, Owzar, K, Jiang, C, Batinic-Haberle, I, and Vujaskovic, Z. "Robust rat pulmonary radioprotection by a lipophilic Mn N-alkylpyridylporphyrin, MnTnHex-2-PyP(5+)." Redox biology 2 (January 9, 2014): 400-410.
PMID
24624330
Source
epmc
Published In
Redox Biology
Volume
2
Publish Date
2014
Start Page
400
End Page
410
DOI
10.1016/j.redox.2013.12.017

Erratum: Mechanistic insights into the cytotoxicity and genotoxicity induced by glycidamide in human mammary cells (Mutagenesis (2013) 28:6 (721-729))

Authors
Bandarra, S; Fernandes, AS; Magro, I; Guerreiro, PS; Pingarilho, M; Churchwell, MI; Gil, OM; Batinic-Haberle, I; Gonçalves, S; Rueff, J; Miranda, JP; Marques, MM; Beland, FA; Castro, M; Gaspar, JF; Oliveira, NG
MLA Citation
Bandarra, S, Fernandes, AS, Magro, I, Guerreiro, PS, Pingarilho, M, Churchwell, MI, Gil, OM, Batinic-Haberle, I, Gonçalves, S, Rueff, J, Miranda, JP, Marques, MM, Beland, FA, Castro, M, Gaspar, JF, and Oliveira, NG. "Erratum: Mechanistic insights into the cytotoxicity and genotoxicity induced by glycidamide in human mammary cells (Mutagenesis (2013) 28:6 (721-729))." Mutagenesis 29.1 (January 1, 2014): 97-.
Source
scopus
Published In
Mutagenesis
Volume
29
Issue
1
Publish Date
2014
Start Page
97
DOI
10.1093/mutage/get059

Robust rat pulmonary radioprotection by a lipophilic Mn N-alkylpyridylporphyrin, MnTnHex-2-PyP5+

With the goal to enhance the distribution of cationic Mn porphyrins within mitochondria, the lipophilic Mn(III)meso-tetrakis(N-n-hexylpyridinium-2-yl)porphyrin, MnTnHex-2-PyP 5+ has been synthesized and tested in several different model of diseases, where it shows remarkable efficacy at as low as 50μg/kg single or multiple doses. Yet, in a rat lung radioprotection study, at higher 0.6-1mg/kg doses, due to its high accumulation and micellar character, it became toxic. To avoid the toxicity, herein the pulmonary radioprotection of MnTnHex-2-PyP 5+ was assessed at 50μg/kg. Fischer rats were irradiated to their right hemithorax (28Gy) and treated with 0.05mg/kg/day of MnTnHex-2-PyP 5+ for 2 weeks by subcutaneously-implanted osmotic pumps, starting at 2h post-radiation. The body weights and breathing frequencies were followed for 10 weeks post-radiation, when the histopathology and immunohistochemistry were assessed. Impact of MnTnHex-2-PyP 5+ on macrophage recruitment (ED-1), DNA oxidative damage (8-OHdG), TGF-β1, VEGF(A) and HIF-1α were measured. MnTnHex-2-PyP 5+ significantly decreased radiation-induced lung histopathological (H & E staining) and functional damage (breathing frequencies), suppressed oxidative stress directly (8-OHdG), or indirectly, affecting TGF-β1, VEGF (A) and HIF-1α pathways. The magnitude of the therapeutic effects is similar to the effects demonstrated under same experimental conditions with 120-fold higher dose of ~5000-fold less lipophilic Mn(III)meso-tetrakis(N-ethylpyridinium-2-yl)porphyrin, MnTE-2-PyP 5+ . © 2014 The Authors.

Authors
Gauter-Fleckenstein, B; Reboucas, JS; Fleckenstein, K; Tovmasyan, A; Owzar, K; Jiang, C; Batinic-Haberle, I; Vujaskovic, Z
MLA Citation
Gauter-Fleckenstein, B, Reboucas, JS, Fleckenstein, K, Tovmasyan, A, Owzar, K, Jiang, C, Batinic-Haberle, I, and Vujaskovic, Z. "Robust rat pulmonary radioprotection by a lipophilic Mn N-alkylpyridylporphyrin, MnTnHex-2-PyP5+." Redox Biology 2.1 (January 1, 2014): 400-410.
Source
scopus
Published In
Redox Biology
Volume
2
Issue
1
Publish Date
2014
Start Page
400
End Page
410
DOI
10.1016/j.redox.2013.12.017

Targeting mitochondria by Zn(II)N-alkylpyridylporphyrins: the impact of compound sub-mitochondrial partition on cell respiration and overall photodynamic efficacy.

Mitochondria play a key role in aerobic ATP production and redox control. They harness crucial metabolic pathways and control cell death mechanisms, properties that make these organelles essential for survival of most eukaryotic cells. Cancer cells have altered cell death pathways and typically show a shift towards anaerobic glycolysis for energy production, factors which point to mitochondria as potential culprits in cancer development. Targeting mitochondria is an attractive approach to tumor control, but design of pharmaceutical agents based on rational approaches is still not well established. The aim of this study was to investigate which structural features of specially designed Zn(II)N-alkylpyridylporphyrins would direct them to mitochondria and to particular mitochondrial targets. Since Zn(II)N-alkylpyridylporphyrins can act as highly efficient photosensitizers, their localization can be confirmed by photodamage to particular mitochondrial components. Using cultured LS174T adenocarcinoma cells, we found that subcellular distribution of Zn-porphyrins is directed by the nature of the substituents attached to the meso pyridyl nitrogens at the porphyrin ring. Increasing the length of the aliphatic chain from one carbon (methyl) to six carbons (hexyl) increased mitochondrial uptake of the compounds. Such modifications also affected sub-mitochondrial distribution of the Zn-porphyrins. The amphiphilic hexyl derivative (ZnTnHex-2-PyP) localized in the vicinity of cytochrome c oxidase complex, causing its inactivation during illumination. Photoinactivation of critical cellular targets explains the superior efficiency of the hexyl derivative in causing mitochondrial photodamage, and suppressing cellular respiration and survival. Design of potent photosensitizers and redox-active scavengers of free radicals should take into consideration not only selective organelle uptake and localization, but also selective targeting of critical macromolecular structures.

Authors
Odeh, AM; Craik, JD; Ezzeddine, R; Tovmasyan, A; Batinic-Haberle, I; Benov, LT
MLA Citation
Odeh, AM, Craik, JD, Ezzeddine, R, Tovmasyan, A, Batinic-Haberle, I, and Benov, LT. "Targeting mitochondria by Zn(II)N-alkylpyridylporphyrins: the impact of compound sub-mitochondrial partition on cell respiration and overall photodynamic efficacy." PloS one 9.9 (January 2014): e108238-.
PMID
25250732
Source
epmc
Published In
PloS one
Volume
9
Issue
9
Publish Date
2014
Start Page
e108238
DOI
10.1371/journal.pone.0108238

Differential localization and potency of manganese porphyrin superoxide dismutase-mimicking compounds in Saccharomyces cerevisiae.

Cationic Mn(III) porphyrin complexes based on MnTM-2-PyP are among the most promising superoxide dismutase (SOD) mimicking compounds being considered as potential anti-inflammatory drugs. We studied four of these active compounds in the yeast Saccharomyces cerevisiae, MnTM-2-PyP, MnTE-2-PyP, MnTnHex-2-PyP, and MnTnBu-2-PyP, each of which differs only in the length of its alkyl substituents. Each was active in improving the aerobic growth of yeast lacking SOD (sod1∆) in complete medium, and the efficacy of each mimic was correlated with its characteristic catalytic activity. We also studied the partitioning of these compounds between mitochondria and cytosol and found that the more hydrophobic members of the series accumulated in the mitochondria. Moreover, the degree to which a mimic mitigated the sod1Δ auxotrophic phenotype for lysine relative to its auxotrophic phenotype for methionine depended upon its level of lipophilicity-dependent accumulation inside the mitochondria. We conclude that localization within the cell is an important factor in biological efficacy in addition to the degree of catalytic activity, and we discuss possible explanations for this effect.

Authors
Li, AM; Martins, J; Tovmasyan, A; Valentine, JS; Batinic-Haberle, I; Spasojevic, I; Gralla, EB
MLA Citation
Li, AM, Martins, J, Tovmasyan, A, Valentine, JS, Batinic-Haberle, I, Spasojevic, I, and Gralla, EB. "Differential localization and potency of manganese porphyrin superoxide dismutase-mimicking compounds in Saccharomyces cerevisiae." Redox biology 3 (January 2014): 1-6.
PMID
25462059
Source
epmc
Published In
Redox Biology
Volume
3
Publish Date
2014
Start Page
1
End Page
6
DOI
10.1016/j.redox.2014.09.003

Differential localization and potency of manganese porphyrin superoxide dismutase-mimicking compounds in Saccharomyces cerevisiae

Authors
Li, AM; Martins, J; Tovmasyan, A; Valentine, JS; Batinic-Haberle, I; Spasojevic, I; Gralla, EB
MLA Citation
Li, AM, Martins, J, Tovmasyan, A, Valentine, JS, Batinic-Haberle, I, Spasojevic, I, and Gralla, EB. "Differential localization and potency of manganese porphyrin superoxide dismutase-mimicking compounds in Saccharomyces cerevisiae." REDOX BIOLOGY 3 (2014): 1-6.
Source
wos-lite
Published In
Redox Biology
Volume
3
Publish Date
2014
Start Page
1
End Page
6
DOI
10.1016/j.redox.2014.0.003

Effect of molecular characteristics on cellular uptake, subcellular localization, and phototoxicity of Zn(II) N-alkylpyridylporphyrins.

Tetra-cationic Zn(II) meso-tetrakis(N-alkylpyridinium-2 (or -3 or -4)-yl)porphyrins (ZnPs) with progressively increased lipophilicity were synthesized to investigate how the tri-dimensional shape and lipophilicity of the photosensitizer (PS) affect cellular uptake, subcellular distribution, and photodynamic efficacy. The effect of the tri-dimensional shape of the molecule was studied by shifting the N-alkyl substituent attached to the pyridyl nitrogen from ortho to meta and para positions. Progressive increase of lipophilicity from shorter hydrophilic (methyl) to longer amphiphilic (hexyl) alkyl chains increased the phototoxicity of the ZnP PSs. PS efficacy was also increased for all derivatives when the alkyl substituents were shifted from ortho to meta, and from meta to para positions. Both cellular uptake and subcellular distribution of the PSs were affected by the lipophilicity and the position of the alkyl chains on the periphery of the porphyrin ring. Whereas the hydrophilic ZnPs demonstrated mostly lysosomal distribution, the amphiphilic hexyl derivatives were associated with mitochondria, endoplasmic reticulum, and plasma membrane. A comparison of hexyl isomers revealed that cellular uptake and partition into membranes followed the order para > meta > ortho. Varying the position and length of the alkyl substituents affects (i) the exposure of cationic charges for electrostatic interactions with anionic biomolecules and (ii) the lipophilicity of the molecule. The charge, lipophilicity, and the tri-dimensional shape of the PS are the major factors that determine cellular uptake, subcellular distribution, and as a consequence, the phototoxicity of the PSs.

Authors
Ezzeddine, R; Al-Banaw, A; Tovmasyan, A; Craik, JD; Batinic-Haberle, I; Benov, LT
MLA Citation
Ezzeddine, R, Al-Banaw, A, Tovmasyan, A, Craik, JD, Batinic-Haberle, I, and Benov, LT. "Effect of molecular characteristics on cellular uptake, subcellular localization, and phototoxicity of Zn(II) N-alkylpyridylporphyrins." J Biol Chem 288.51 (December 20, 2013): 36579-36588.
PMID
24214973
Source
pubmed
Published In
The Journal of biological chemistry
Volume
288
Issue
51
Publish Date
2013
Start Page
36579
End Page
36588
DOI
10.1074/jbc.M113.511642

Mn porphyrin regulation of aerobic glycolysis: implications on the activation of diabetogenic immune cells.

AIMS: The immune system is critical for protection against infections and cancer, but requires scrupulous regulation to limit self-reactivity and autoimmunity. Our group has utilized a manganese porphyrin catalytic antioxidant (MnTE-2-PyP(5+), MnP) as a potential immunoregulatory therapy for type 1 diabetes. MnP has previously been shown to modulate diabetogenic immune responses through decreases in proinflammatory cytokine production from antigen-presenting cells and T cells and to reduce diabetes onset in nonobese diabetic mice. However, it is unclear whether or not MnP treatment can act beyond the reported inflammatory mediators. Therefore, the hypothesis that MnP may be affecting the redox-dependent bioenergetics of diabetogenic splenocytes was investigated. RESULTS: MnP treatment enhanced glucose oxidation, reduced fatty acid oxidation, but only slightly decreased overall oxidative phosphorylation. These alterations occurred because of increased tricarboxylic acid cycle aconitase enzyme efficiency and were not due to changes in mitochondrial abundance. MnP treatment also displayed decreased aerobic glycolysis, which promotes activated immune cell proliferation, as demonstrated by reduced lactate production and glucose transporter 1 (Glut1) levels and inactivation of key signaling molecules, such as mammalian target of rapamycin, c-myc, and glucose-6-phosphate dehydrogenase. INNOVATION: This work highlights the importance of redox signaling by demonstrating that modulation of reactive oxygen species can supplant complex downstream regulation, thus affecting metabolic programming toward aerobic glycolysis. CONCLUSION: MnP treatment promotes metabolic quiescence, impeding diabetogenic autoimmune responses by restricting the metabolic pathways for energy production and affecting anabolic processes necessary for cell proliferation.

Authors
Delmastro-Greenwood, MM; Votyakova, T; Goetzman, E; Marre, ML; Previte, DM; Tovmasyan, A; Batinic-Haberle, I; Trucco, MM; Piganelli, JD
MLA Citation
Delmastro-Greenwood, MM, Votyakova, T, Goetzman, E, Marre, ML, Previte, DM, Tovmasyan, A, Batinic-Haberle, I, Trucco, MM, and Piganelli, JD. "Mn porphyrin regulation of aerobic glycolysis: implications on the activation of diabetogenic immune cells." Antioxid Redox Signal 19.16 (December 1, 2013): 1902-1915.
PMID
23682840
Source
pubmed
Published In
Antioxidants & Redox Signaling
Volume
19
Issue
16
Publish Date
2013
Start Page
1902
End Page
1915
DOI
10.1089/ars.2012.5167

Pharmacokinetics, Brain Hippocampus and Cortex, and Mitochondrial Accumulation of a New Generation of Lipophilic Redox-Active Therapeutic, Mn(III) Meso Tetrakis(N-n-butoxyethylpyridinium-2-yl)porphyrin, MnTnBuOE-2-PyP5+, in Comparison with its Ethyl and N-hexyl Analogs, MnTE-2-PyP5+ and MnTnHex-2-PyP5+

Authors
Spasojevic, I; Weitner, T; Tovmasyan, A; Sheng, H; Miriyala, S; Leu, D; Rajic, Z; Warner, DS; Clair, DS; Huang, T-T; Batinic-Haberle, I
MLA Citation
Spasojevic, I, Weitner, T, Tovmasyan, A, Sheng, H, Miriyala, S, Leu, D, Rajic, Z, Warner, DS, Clair, DS, Huang, T-T, and Batinic-Haberle, I. "Pharmacokinetics, Brain Hippocampus and Cortex, and Mitochondrial Accumulation of a New Generation of Lipophilic Redox-Active Therapeutic, Mn(III) Meso Tetrakis(N-n-butoxyethylpyridinium-2-yl)porphyrin, MnTnBuOE-2-PyP5+, in Comparison with its Ethyl and N-hexyl Analogs, MnTE-2-PyP5+ and MnTnHex-2-PyP5+." Free Radical Biology and Medicine 65 (November 2013): S132-S132.
Source
crossref
Published In
Free Radical Biology & Medicine
Volume
65
Publish Date
2013
Start Page
S132
End Page
S132
DOI
10.1016/j.freeradbiomed.2013.10.728

Mechanistic insights into the cytotoxicity and genotoxicity induced by glycidamide in human mammary cells.

Acrylamide (AA) is a well-known industrial chemical classified as a probable human carcinogen. Benign and malignant tumours at different sites, including the mammary gland, have been reported in rodents exposed to AA. This xenobiotic is also formed in many carbohydrate-rich foods prepared at high temperatures. For this reason, AA is an issue of concern in terms of human cancer risk. The epoxide glycidamide (GA) is thought to be the ultimate genotoxic AA metabolite. Despite extensive experimental and epidemiological data focused on AA-induced breast cancer, there is still lack of information on the deleterious effects induced by GA in mammary cells. The work reported here addresses the characterisation and modulation of cytotoxicity, generation of reactive oxygen species, formation of micronuclei (MN) and quantification of specific GA-DNA adducts in human MCF10A epithelial cells exposed to GA. The results show that GA significantly induces MN, impairs cell proliferation kinetics and decreases cell viability at high concentrations by mechanisms not involving oxidative stress. KU55933, an inhibitor of ataxia telangiectasia mutated kinase, enhanced the cytotoxicity of GA (P < 0.05), supporting a role of this enzyme in regulating the repair of GA-induced DNA lesions. Moreover, even at low GA levels, N7-GA-Gua adducts were generated in a linear dose-response manner in MCF10A cells. These results confirm that human mammary cells are susceptible to GA toxicity and reinforce the need for additional studies to clarify the potential correlation between dietary AA exposure and breast cancer risk in human populations.

Authors
Bandarra, S; Fernandes, AS; Magro, I; Guerreiro, PS; Pingarilho, M; Churchwell, MI; Gil, OM; Batinic-Haberle, I; Gonçalves, S; Rueff, J; Miranda, JP; Marques, MM; Beland, FA; Castro, M; Gaspar, JF; Oliveira, NG
MLA Citation
Bandarra, S, Fernandes, AS, Magro, I, Guerreiro, PS, Pingarilho, M, Churchwell, MI, Gil, OM, Batinic-Haberle, I, Gonçalves, S, Rueff, J, Miranda, JP, Marques, MM, Beland, FA, Castro, M, Gaspar, JF, and Oliveira, NG. "Mechanistic insights into the cytotoxicity and genotoxicity induced by glycidamide in human mammary cells." Mutagenesis 28.6 (November 2013): 721-729.
PMID
24150595
Source
pubmed
Published In
Mutagenesis
Volume
28
Issue
6
Publish Date
2013
Start Page
721
End Page
729
DOI
10.1093/mutage/get052

Acid-base and electrochemical properties of manganese meso(ortho- and meta-N-ethylpyridyl)porphyrins: voltammetric and chronocoulometric study of protolytic and redox equilibria.

Growing interest in redox-active compounds as therapeutics for oxidative stress-related diseases led to the design of metalloporphyrins as some of the most potent functional SOD-mimics. Herein we report a detailed electrochemical study of the protolytic and redox equilibria of manganese ortho and meta substituted N-ethylpyridyl porphyrins (MnPs), MnTE-2-PyP(5+) and MnTE-3-PyP(5+), in aqueous solutions. The electrochemical parameters of redox processes for all experimentally available species have been determined, as well as their diffusion coefficients and estimated sizes of aqueous cavities. The results indicate that possible changes of the intracellular acidity cannot affect the antioxidant activity of MnPs in vivo, since no change in the E(Mn(III)P/Mn(II)P) values was observed below pH 10. Furthermore, the results confirm that both of these MnPs can be efficient redox scavengers of peroxynitrite (ONOO(-)), another major damaging species in vivo. This can occur by either single-electron reduction or two-electron reduction of ONOO(-), involving either the Mn(IV)P/Mn(III)P redox couple or Mn(IV)P/Mn(II)P redox couple. In addition to kred(ONOO(-)) reported previously, the thermodynamic parameters calculated herein imply a strong and identical driving force for the reaction of both ortho and meta isomeric MnPs with ONOO(-). An enlargement of both Mn(III)P complexes upon an increase of the solution pH was also observed and attributed to the reduction of positive charge on the central ion caused by deprotonation of the axial water molecules. This expansion of aqueous cavities suggests the formation of a solvent cage and the increased lipophilicity of Mn(III)P complexes caused by increased electron density on the Mn ion.

Authors
Weitner, T; Kos, I; Mandić, Z; Batinić-Haberle, I; Biruš, M
MLA Citation
Weitner, T, Kos, I, Mandić, Z, Batinić-Haberle, I, and Biruš, M. "Acid-base and electrochemical properties of manganese meso(ortho- and meta-N-ethylpyridyl)porphyrins: voltammetric and chronocoulometric study of protolytic and redox equilibria." Dalton Trans 42.41 (October 1, 2013): 14757-14765.
PMID
23933742
Source
pubmed
Published In
Dalton Transactions
Volume
42
Issue
41
Publish Date
2013
Start Page
14757
End Page
14765
DOI
10.1039/c3dt50767j

Late administration of Mn porphyrin-based SOD mimic enhances diabetic complications

Mn(III) N-alkylpyridylporphyrins (MnPs) have demonstrated protection in various conditions where increased production of reactive oxygen/reactive nitrogen species (ROS/RNS), is a key pathological factors. MnPs can produce both pro-oxidative and antioxidative effects depending upon the cellular redox environment that they encounter. Previously we reported (Free Radic. Res. 39: 81-8, 2005) that when the treatment started at the onset of diabetes, Mn(III) meso-tetrakis(N-methylpyridinium-2-yl)porphyrin, MnTM-2-PyP 5+ suppressed diabetes-induced oxidative stress. Diabetes, however, is rarely diagnosed at its onset. The aim of this study was to investigate if MnTM-2-PyP 5+ can suppress oxidative damage and prevent diabetic complications when administered more than a week after the onset of diabetes. Diabetes was induced by streptozotocin. The MnP-based treatment started 8 days after the onset of diabetes and continued for 2 months. The effect of the treatment on activities of glutathione peroxidase, superoxide dismutase, catalase, glutathione reductase, glucose-6-phosphate dehydrogenase, glyceraldehyde-3-phosphate dehydrogenase, and glyoxalases I and II as well as malondialdehyde and GSH/GSSG ratio were determined in kidneys. Kidney function was assessed by measuring lysozyme and total protein in urine and blood urea nitrogen. Vascular damage was evaluated by assessing vascular reactivity. Our data showed that delayed administration of MnTM-2-PyP 5+ did not protect against oxidative damage and did not prevent diabetic complications. Moreover, MnTM-2-PyP 5+ contributed to the kidney damage, which seems to be a consequence of its pro-oxidative action. Such outcome can be explained by advanced oxidative damage which already existed at the moment the therapy with MnP started. The data support the concept that the overall biological effect of a redox-active MnP is determined by (i) the relative concentrations of oxidants and reductants, i.e. the cellular redox environment and (ii) MnP biodistribution. © 2013 The Authors.

Authors
Ali, DK; Oriowo, M; Tovmasyan, A; Batinic-Haberle, I; Benov, L
MLA Citation
Ali, DK, Oriowo, M, Tovmasyan, A, Batinic-Haberle, I, and Benov, L. "Late administration of Mn porphyrin-based SOD mimic enhances diabetic complications." Redox Biology 1.1 (September 12, 2013): 457-466.
PMID
24191241
Source
scopus
Published In
Redox Biology
Volume
1
Issue
1
Publish Date
2013
Start Page
457
End Page
466
DOI
10.1016/j.redox.2013.09.005

The copper chelator ATN-224 induces peroxynitrite-dependent cell death in hematological malignancies.

Chemoresistance due to oxidative stress resistance or upregulation of Bcl-2 contributes to poor outcome in the treatment of hematological malignancies. In this study, we utilize the copper-chelator drug ATN-224 (choline tetrathiomolybdate) to induce cell death in oxidative stress-resistant cells and cells overexpressing Bcl-2 by modulating the cellular redox environment and causing mitochondrial dysfunction. ATN-224 treatment decreases superoxide dismutase 1 (SOD1) activity, increases intracellular oxidants, and induces peroxynitrite-dependent cell death. ATN-224 also targets the mitochondria, decreasing both cytochrome c oxidase (CcOX) activity and mitochondrial membrane potential. The concentration of ATN-224 required to induce cell death is proportional to SOD1 levels, but independent of Bcl-2 status. In combination with doxorubicin, ATN-224 enhances cell death. In primary B-cell acute lymphoblastic leukemia patient samples, ATN-224 decreases the viable cell number. Our findings suggest that ATN-224's dual targeting of SOD1 and CcOX is a promising approach for treatment of hematological malignancies either as an adjuvant or as a single agent.

Authors
Lee, K; Briehl, MM; Mazar, AP; Batinic-Haberle, I; Reboucas, JS; Glinsmann-Gibson, B; Rimsza, LM; Tome, ME
MLA Citation
Lee, K, Briehl, MM, Mazar, AP, Batinic-Haberle, I, Reboucas, JS, Glinsmann-Gibson, B, Rimsza, LM, and Tome, ME. "The copper chelator ATN-224 induces peroxynitrite-dependent cell death in hematological malignancies." Free Radic Biol Med 60 (July 2013): 157-167.
PMID
23416365
Source
pubmed
Published In
Free Radical Biology and Medicine
Volume
60
Publish Date
2013
Start Page
157
End Page
167
DOI
10.1016/j.freeradbiomed.2013.02.003

Differential coordination demands in Fe versus Mn water-soluble cationic metalloporphyrins translate into remarkably different aqueous redox chemistry and biology.

The different biological behavior of cationic Fe and Mn pyridylporphyrins in Escherichia coli and mouse studies prompted us to revisit and compare their chemistry. For that purpose, the series of ortho and meta isomers of Fe(III) meso-tetrakis-N-alkylpyridylporphyrins, alkyl being methyl to n-octyl, were synthesized and characterized by elemental analysis, UV/vis spectroscopy, mass spectrometry, lipophilicity, protonation equilibria of axial waters, metal-centered reduction potential, E(1/2) for M(III)P/M(II)P redox couple (M = Fe, Mn, P = porphyrin), kcat for the catalysis of O2(•-) dismutation, stability toward peroxide-driven porphyrin oxidative degradation (produced in the catalysis of ascorbate oxidation by MP), ability to affect growth of SOD-deficient E. coli, and toxicity to mice. Electron-deficiency of the metal site is modulated by the porphyrin ligand, which renders Fe(III) porphyrins ≥5 orders of magnitude more acidic than the analogous Mn(III) porphyrins, as revealed by the pKa1 of axially coordinated waters. The 5 log units difference in the acidity between the Mn and Fe sites in porphyrin translates into the predominance of tetracationic (OH)(H2O)FeP complexes relative to pentacationic (H2O)2MnP species at pH ∼7.8. This is additionally evidenced in large differences in the E(1/2) values of M(III)P/M(II)P redox couples. The presence of hydroxo ligand labilizes trans-axial water which results in higher reactivity of Fe relative to Mn center. The differences in the catalysis of O2(•-) dismutation (log kcat) between Fe and Mn porphyrins is modest, 2.5-5-fold, due to predominantly outer-sphere, with partial inner-sphere character of two reaction steps. However, the rate constant for the inner-sphere H2O2-based porphyrin oxidative degradation is 18-fold larger for (OH)(H2O)FeP than for (H2O)2MnP. The in vivo consequences of the differences between the Fe and Mn porphyrins were best demonstrated in SOD-deficient E. coli growth. On the basis of fairly similar log kcat(O2(•-)) values, a very similar effect on the growth of SOD-deficient E. coli was anticipated by both metalloporphyrins. Yet, while (H2O)2MnTE-2-PyP(5+) was fully efficacious at ≥20 μM, the Fe analogue (OH)(H2O)FeTE-2-PyP(4+) supported SOD-deficient E. coli growth at as much as 200-fold lower doses in the range of 0.1-1 μM. Moreover the pattern of SOD-deficient E. coli growth was different with Mn and Fe porphyrins. Such results suggested a different mode of action of these metalloporphyrins. Further exploration demonstrated that (1) 0.1 μM (OH)(H2O)FeTE-2-PyP(4+) provided similar growth stimulation as the 0.1 μM Fe salt, while the 20 μM Mn salt provides no protection to E. coli; and (2) 1 μM Fe porphyrin is fully degraded by 12 h in E. coli cytosol and growth medium, while Mn porphyrin is not. Stimulation of the aerobic growth of SOD-deficient E. coli by the Fe porphyrin is therefore due to iron acquisition. Our data suggest that in vivo, redox-driven degradation of Fe porphyrins resulting in Fe release plays a major role in their biological action. Possibly, iron reconstitutes enzymes bearing [4Fe-4S] clusters as active sites. Under the same experimental conditions, (OH)(H2O)FePs do not cause mouse arterial hypotension, whereas (H2O)2MnPs do, which greatly limits the application of Mn porphyrins in vivo.

Authors
Tovmasyan, A; Weitner, T; Sheng, H; Lu, M; Rajic, Z; Warner, DS; Spasojevic, I; Reboucas, JS; Benov, L; Batinic-Haberle, I
MLA Citation
Tovmasyan, A, Weitner, T, Sheng, H, Lu, M, Rajic, Z, Warner, DS, Spasojevic, I, Reboucas, JS, Benov, L, and Batinic-Haberle, I. "Differential coordination demands in Fe versus Mn water-soluble cationic metalloporphyrins translate into remarkably different aqueous redox chemistry and biology." Inorg Chem 52.10 (May 20, 2013): 5677-5691.
PMID
23646875
Source
pubmed
Published In
Inorganic Chemistry
Volume
52
Issue
10
Publish Date
2013
Start Page
5677
End Page
5691
DOI
10.1021/ic3012519

Comprehensive pharmacokinetic studies and oral bioavailability of two Mn porphyrin-based SOD mimics, MnTE-2-PyP5+ and MnTnHex-2-PyP5+.

The cationic, ortho Mn(III) N-alkylpyridylporphyrins (alkyl=ethyl, E, and n-hexyl, nHex) MnTE-2-PyP(5+) (AEOL10113, FBC-007) and MnTnHex-2-PyP(5+) have proven efficacious in numerous in vivo animal models of diseases having oxidative stress in common. The remarkable therapeutic efficacy observed is due to their: (1) ability to catalytically remove O2(•-) and ONOO(-) and other reactive species; (2) ability to modulate redox-based signaling pathways; (3) accumulation within critical cellular compartments, i.e., mitochondria; and (4) ability to cross the blood-brain barrier. The similar redox activities of both compounds are related to the similar electronic and electrostatic environments around the metal active sites, whereas their different bioavailabilities are presumably influenced by the differences in lipophilicity, bulkiness, and shape. Both porphyrins are water soluble, but MnTnHex-2-PyP(5+) is approximately 4 orders of magnitude more lipophilic than MnTE-2-PyP(5+), which should positively affect its ability to pass through biological membranes, making it more efficacious in vivo at lower doses. To gain insight into the in vivo tissue distribution of Mn porphyrins and its impact upon their therapeutic efficacy and mechanistic aspects of action, as well as to provide data that would ensure proper dosing regimens, we conducted comprehensive pharmacokinetic (PK) studies for 24h after single-dose drug administration. The porphyrins were administered intravenously (iv), intraperitoneally (ip), and via oral gavage at the following doses: 10mg/kg MnTE-2-PyP(5+) and 0.5 or 2mg/kg MnTnHex-2-PyP(5+). Drug levels in plasma and various organs (liver, kidney, spleen, heart, lung, brain) were determined and PK parameters calculated (Cmax, C24h, tmax, and AUC). Regardless of high water solubility and pentacationic charge of these Mn porphyrins, they are orally available. The oral availability (based on plasma AUCoral/AUCiv) is 23% for MnTE-2-PyP(5+) and 21% for MnTnHex-2-PyP(5+). Despite the fivefold lower dose administered, the AUC values for liver, heart, and spleen are higher for MnTnHex-2-PyP(5+) than for MnTE-2-PyP(5+) (and comparable for other organs), clearly demonstrating the better tissue penetration and tissue retention of the more lipophilic MnTnHex-2-PyP(5+).

Authors
Weitner, T; Kos, I; Sheng, H; Tovmasyan, A; Reboucas, JS; Fan, P; Warner, DS; Vujaskovic, Z; Batinic-Haberle, I; Spasojevic, I
MLA Citation
Weitner, T, Kos, I, Sheng, H, Tovmasyan, A, Reboucas, JS, Fan, P, Warner, DS, Vujaskovic, Z, Batinic-Haberle, I, and Spasojevic, I. "Comprehensive pharmacokinetic studies and oral bioavailability of two Mn porphyrin-based SOD mimics, MnTE-2-PyP5+ and MnTnHex-2-PyP5+." Free Radic Biol Med 58 (May 2013): 73-80.
PMID
23328731
Source
pubmed
Published In
Free Radical Biology and Medicine
Volume
58
Publish Date
2013
Start Page
73
End Page
80
DOI
10.1016/j.freeradbiomed.2013.01.006

Intracellular targeting and pharmacological activity of the superoxide dismutase mimics MnTE-2-PyP5+ and MnTnHex-2-PyP5+ regulated by their porphyrin ring substituents.

Manganese porphyrin-based drugs are potent mimics of the enzyme superoxide dismutase. They exert remarkable efficacy in disease models and are entering clinical trials. Two lead compounds, MnTE-2-PyP(5+) and MnTnHex-2-PyP(5+), have similar catalytic rates, but differ in their alkyl chain substituents (ethyl vs n-hexyl). Herein we demonstrate that these changes in ring substitution impact upon drug intracellular distribution and pharmacological mechanism, with MnTnHex-2-PyP(5+) superior in augmenting menadione toxicity. These findings establish that both catalytic activity and intracellular distribution determine drug action.

Authors
Aitken, JB; Shearer, EL; Giles, NM; Lai, B; Vogt, S; Reboucas, JS; Batinic-Haberle, I; Lay, PA; Giles, GI
MLA Citation
Aitken, JB, Shearer, EL, Giles, NM, Lai, B, Vogt, S, Reboucas, JS, Batinic-Haberle, I, Lay, PA, and Giles, GI. "Intracellular targeting and pharmacological activity of the superoxide dismutase mimics MnTE-2-PyP5+ and MnTnHex-2-PyP5+ regulated by their porphyrin ring substituents." Inorg Chem 52.8 (April 15, 2013): 4121-4123.
PMID
23551184
Source
pubmed
Published In
Inorganic Chemistry
Volume
52
Issue
8
Publish Date
2013
Start Page
4121
End Page
4123
DOI
10.1021/ic300700g

The administration of renoprotective agents extends warm ischemia in a rat model.

BACKGROUND AND PURPOSE: Extended warm ischemia time during partial nephrectomy leads to considerable renal injury. Using a rat model of renal ischemia, we examined the ability of a unique renoprotective cocktail to ameliorate warm ischemia-reperfusion injury and extend warm ischemia time. MATERIALS AND METHODS: A warm renal ischemia model was developed using Sprague-Dawley rats, clamping the left renal artery for 40, 50, 60, and 70 minutes, followed by 48 hours of reperfusion. An improved renoprotective cocktail referred to as I-GPM (a mixture of specific renoprotective growth factors, porphyrins, and mitochondria-protecting amino acids) was administered -24 hours, 0 hours, and +24 hours after surgery. At 48 hours, both kidneys were harvested and examined with hematoxylin and eosin and periodic acid-Schiff stains for the analysis of renal tubular necrosis. Creatinine, protein, and gene expression levels were also analyzed to evaluate several ischemia-specific and antioxidant response markers. RESULTS: I-GPM treated kidneys showed significant reversal of morphologic changes and a significant reduction in specific ischemic markers lipocalin-2, galectin-3, GRP-78, and HMGB1 compared with ischemic controls. These experiments also showed an upregulation of the stress response protein, heat shock protein (HSP)-70, as well as the phosphorylated active form of the transcription factor, heat shock factor (HSF)-1. In addition, quantitative RT-PCR analyses revealed a robust upregulation of several antioxidant pathway response genes in I-GPM treated animals. CONCLUSIONS: By histopathologic and several molecular measures, our unique renoprotective cocktail mitigated ischemia-reperfusion injury. Our cocktail minimized oxidative stress in an ischemic kidney rat model while at the same time protecting the global parenchymal function during extended periods of ischemia.

Authors
Cohen, J; Dorai, T; Ding, C; Batinic-Haberle, I; Grasso, M
MLA Citation
Cohen, J, Dorai, T, Ding, C, Batinic-Haberle, I, and Grasso, M. "The administration of renoprotective agents extends warm ischemia in a rat model." J Endourol 27.3 (March 2013): 343-348.
PMID
23102208
Source
pubmed
Published In
Journal of Endourology
Volume
27
Issue
3
Publish Date
2013
Start Page
343
End Page
348
DOI
10.1089/end.2012.0194

Radiation induces aerobic glycolysis through reactive oxygen species.

BACKGROUND AND PURPOSE: Although radiation induced reoxygenation has been thought to increase radiosensitivity, we have shown that its associated oxidative stress can have radioprotective effects, including stabilization of the transcription factor hypoxia inducible factor 1 (HIF-1). HIF-1 is known to regulate many of the glycolytic enzymes, thereby promoting aerobic glycolysis, which is known to promote treatment resistance. Thus, we hypothesized that reoxygenation after radiation would increase glycolysis. We previously showed that blockade of oxidative stress using a superoxide dismutase (SOD) mimic during reoxygenation can downregulate HIF-1 activity. Here we tested whether concurrent use of this drug with radiotherapy would reduce the switch to a glycolytic phenotype. MATERIALS AND METHODS: 40 mice with skin fold window chambers implanted with 4T1 mammary carcinomas were randomized into (1) no treatment, (2) radiation alone, (3) SOD mimic alone, and (4) SOD mimic with concurrent radiation. All mice were imaged on the ninth day following tumor implantation (30 h following radiation treatment) following injection of a fluorescent glucose analog, 2-[N-(7-nitrobenz-2-oxa-1,3-diaxol-4-yl)amino]-2-deoxyglucose (2-NBDG). Hemoglobin saturation was measured by using hyperspectral imaging to quantify oxygenation state. RESULTS: Mice treated with radiation showed significantly higher 2-NBDG fluorescence compared to controls (p=0.007). Hemoglobin saturation analysis demonstrated reoxygenation following radiation, coinciding with the observed increase in glycolysis. The concurrent use of the SOD mimic with radiation demonstrated a significant reduction in 2-NBDG fluorescence compared to effects seen after radiation alone, while having no effect on reoxygenation. CONCLUSIONS: Radiation induces an increase in tumor glucose demand approximately 30 h following therapy during reoxygenation. The use of an SOD mimic can prevent the increase in aerobic glycolysis when used concurrently with radiation, without preventing reoxygenation.

Authors
Zhong, J; Rajaram, N; Brizel, DM; Frees, AE; Ramanujam, N; Batinic-Haberle, I; Dewhirst, MW
MLA Citation
Zhong, J, Rajaram, N, Brizel, DM, Frees, AE, Ramanujam, N, Batinic-Haberle, I, and Dewhirst, MW. "Radiation induces aerobic glycolysis through reactive oxygen species." Radiother Oncol 106.3 (March 2013): 390-396.
PMID
23541363
Source
pubmed
Published In
Radiotherapy and Oncology
Volume
106
Issue
3
Publish Date
2013
Start Page
390
End Page
396
DOI
10.1016/j.radonc.2013.02.013

Thermal stability of the prototypical Mn porphyrin-based superoxide dismutase mimic and potent oxidative-stress redox modulator Mn(III) meso-tetrakis(N-ethylpyridinium-2-yl)porphyrin chloride, MnTE-2-PyP(5+).

Cationic Mn porphyrins are among the most potent catalytic antioxidants and/or cellular redox modulators. Mn(III) meso-tetrakis(N-ethylpyridinium-2-yl)porphyrin chloride (MnTE-2-PyPCl(5)) is the Mn porphyrin most studied in vivo and has successfully rescued animal models of a variety of oxidative stress-related diseases. The stability of an authentic MnTE-2-PyPCl(5) sample was investigated hereon by thermogravimetric, derivative thermogravimetric, and differential thermal analyses (TG/DTG/DTA), under dynamic air, followed by studies at selected temperatures to evaluate the decomposition path and appropriate conditions for storage and handling of these materials. All residues were analyzed by thin-layer chromatography (TLC) and UV-vis spectroscopy. Three thermal processes were observed by TG/DTG. The first event (endothermic) corresponded to dehydration, and did not alter the MnTE-2-PyPCl(5) moiety. The second event (endothermic) corresponded to the loss of EtCl (dealkylation), which was characterized by gas chromatography-mass spectrometry. The residue at 279°C had UV-vis and TLC data consistent with those of the authentic, completely dealkylated analog, MnT-2-PyPCl. The final, multi-step event corresponded to the loss of the remaining organic matter to yield Mn(3)O(4) which was characterized by IR spectroscopy. Isothermal treatment at 188°C under static air for 3h yielded a mixture of partially dealkylated MnPs and traces of the free-base, dealkylated ligand, H(2)T-2-PyP, which reveals that dealkylation is accompanied by thermal demetallation under static air conditions. Dealkylation was not observed if the sample was heated as a solid or in aqueous solution up to ∼100°C. Whereas moderate heating changes sample composition by loss of H(2)O, the dehydrated sample is indistinguishable from the original sample upon dissolution in water, which indicates that catalytic activity (on Mn basis) remains unaltered. Evidently, dealkylation at high temperature compromises sample activity.

Authors
Pinto, VHA; Carvalhoda-Silva, D; Santos, JLMS; Weitner, T; Fonseca, MG; Yoshida, MI; Idemori, YM; Batinić-Haberle, I; Rebouças, JS
MLA Citation
Pinto, VHA, Carvalhoda-Silva, D, Santos, JLMS, Weitner, T, Fonseca, MG, Yoshida, MI, Idemori, YM, Batinić-Haberle, I, and Rebouças, JS. "Thermal stability of the prototypical Mn porphyrin-based superoxide dismutase mimic and potent oxidative-stress redox modulator Mn(III) meso-tetrakis(N-ethylpyridinium-2-yl)porphyrin chloride, MnTE-2-PyP(5+)." J Pharm Biomed Anal 73 (January 25, 2013): 29-34.
PMID
22503130
Source
pubmed
Published In
Journal of Pharmaceutical and Biomedical Analysis
Volume
73
Publish Date
2013
Start Page
29
End Page
34
DOI
10.1016/j.jpba.2012.03.033

Peroxynitrite formation in nitric oxide-exposed submitochondrial particles: detection, oxidative damage and catalytic removal by Mn-porphyrins.

Peroxynitrite (ONOO(-)) formation in mitochondria may be favored due to the constant supply of superoxide radical (O(2)(∙-)) by the electron transport chain plus the facile diffusion of nitric oxide ((∙)NO) to this organelle. Herein, a model system of submitochondrial particles (SMP) in the presence of succinate plus the respiratory inhibitor antimycin A (to increase O(2)(∙-) rates) and the (∙)NO-donor NOC-7 was studied to directly establish and quantitate peroxynitrite by a multiplicity of methods including chemiluminescence, fluorescence and immunochemical analysis. While all the tested probes revealed peroxynitrite at near stoichiometric levels with respect to its precursor radicals, coumarin boronic acid (a probe that directly reacts with peroxynitrite) had the more straightforward oxidation profile from O(2)(∙-)-forming SMP as a function of the (∙)NO flux. Interestingly, immunospintrapping studies verified protein radical generation in SMP by peroxynitrite. Substrate-supplemented SMP also reduced Mn(III)porphyrins (MnP) to Mn(II)P under physiologically-relevant oxygen levels (3-30 μM); then, Mn(II)P were capable to reduce peroxynitrite and protect SMP from the inhibition of complex I-dependent oxygen consumption and protein radical formation and nitration of membranes. The data directly support the formation of peroxynitrite in mitochondria and demonstrate that MnP can undergo a catalytic redox cycle to neutralize peroxynitrite-dependent mitochondrial oxidative damage.

Authors
Valez, V; Cassina, A; Batinic-Haberle, I; Kalyanaraman, B; Ferrer-Sueta, G; Radi, R
MLA Citation
Valez, V, Cassina, A, Batinic-Haberle, I, Kalyanaraman, B, Ferrer-Sueta, G, and Radi, R. "Peroxynitrite formation in nitric oxide-exposed submitochondrial particles: detection, oxidative damage and catalytic removal by Mn-porphyrins." Arch Biochem Biophys 529.1 (January 1, 2013): 45-54.
PMID
23142682
Source
pubmed
Published In
Archives of Biochemistry and Biophysics
Volume
529
Issue
1
Publish Date
2013
Start Page
45
End Page
54
DOI
10.1016/j.abb.2012.10.012

Superoxide dismutase mimic, MnTE-2-PyP(5+) ameliorates acute and chronic proctitis following focal proton irradiation of the rat rectum.

Radiation proctitis, an inflammation and damage to the lower part of colon, is a common adverse event of the radiotherapy of tumors in the abdominal and pelvic region (colon, prostate, cervical). Several Mn(III) porphyrin-based superoxide dismutase mimics have been synthesized and successfully evaluated in preclinical models as radioprotectants. Here we report for the first time the remarkable rectal radioprotection of frequently explored Mn(III) meso-tetrakis(N-ethylpyridinium-2-yl)porphyrin, MnTE-2-PyP(5+). A batch prepared in compliance with good manufacturing practice (GMP), which has good safety/toxicity profile, was used for this study. MnTE-2-PyP(5+) was given subcutaneously at 5 mg/kg, either 1 h before or 1 h after irradiation, with additional drug administered at weekly intervals thereafter. MnTE-2-PyP(5+) ameliorated both acute and chronic radiation proctitis in male Sprague-Dawley rats irradiated with 20-30 Gy protons delivered to 2.5 cm span of rectum using spread-out Bragg peak of a proton treatment beam. Focal irradiation of the rectum produced acute proctitis, which healed, followed by chronic rectal dilation and symptomatic proctitis. MnTE-2-PyP(5+) protected rectal mucosa from radiation-induced crypt loss measured 10 days post-irradiation. Significant effects were observed with both pre- and post-treatment regimens. However, only MnTE-2-PyP(5+) pre-treatment, but not post-treatment, prevented the development of rectal dilation, indicating that proper dosing regimen is critical for radioprotection. The pre-treatment also prevented or delayed the development of chronic proctitis depending on the radiation dose. Further work aimed at developing MnTE-2-PyP(5+) and similar drugs as adjunctive agents for radiotherapy of pelvic tumors is warranted. The present study substantiates the prospects of employing this and similar analogs in preserving normal tissue during cancer radiation as well as any other radiation exposure.

Authors
Archambeau, JO; Tovmasyan, A; Pearlstein, RD; Crapo, JD; Batinic-Haberle, I
MLA Citation
Archambeau, JO, Tovmasyan, A, Pearlstein, RD, Crapo, JD, and Batinic-Haberle, I. "Superoxide dismutase mimic, MnTE-2-PyP(5+) ameliorates acute and chronic proctitis following focal proton irradiation of the rat rectum. (Published online)" Redox Biol 1 (2013): 599-607.
PMID
24363995
Source
pubmed
Published In
Redox Biology
Volume
1
Publish Date
2013
Start Page
599
End Page
607
DOI
10.1016/j.redox.2013.10.002

Design, mechanism of action, bioavailability and therapeutic effects of mn porphyrin-based redox modulators.

Based on aqueous redox chemistry and simple in vivo models of oxidative stress, Escherichia coli and Saccharomyces cerevisiae, the cationic Mn(III) N-substituted pyridylporphyrins (MnPs) have been identified as the most potent cellular redox modulators within the porphyrin class of drugs; their efficacy in animal models of diseases that have oxidative stress in common is based on their high ability to catalytically remove superoxide, peroxynitrite, carbonate anion radical, hypochlorite, nitric oxide, lipid peroxyl and alkoxyl radicals, thus suppressing the primary oxidative event. While doing so MnPs could couple with cellular reductants and redox-active proteins. Reactive species are widely accepted as regulators of cellular transcriptional activity: minute, nanomolar levels are essential for normal cell function, while submicromolar or micromolar levels impose oxidative stress, which is evidenced in increased inflammatory and immune responses. By removing reactive species, MnPs affect redox-based cellular transcriptional activity and consequently secondary oxidative stress, and in turn inflammatory processes. The equal ability to reduce and oxidize superoxide during the dismutation process and recently accumulated results suggest that pro-oxidative actions of MnPs may also contribute to their therapeutic effects. All our data identify the superoxide dismutase-like activity, estimated by log k(cat)O2-*), as a good measure for the therapeutic efficacy of MnPs. Their accumulation in mitochondria and their ability to cross the blood-brain barrier contribute to their remarkable efficacy. We summarize herein the therapeutic effects of MnPs in cancer, central nervous system injuries, diabetes, their radioprotective action and potential for imaging. Few of the most potent modulators of cellular redox-based pathways, MnTE2-PyP5+, MnTDE-2-ImP5+, MnTnHex-2-PyP5+ and MnTnBuOE-2-PyP5+, are under preclinical and clinical development.

Authors
Tovmasyan, A; Sheng, H; Weitner, T; Arulpragasam, A; Lu, M; Warner, DS; Vujaskovic, Z; Spasojevic, I; Batinic-Haberle, I
MLA Citation
Tovmasyan, A, Sheng, H, Weitner, T, Arulpragasam, A, Lu, M, Warner, DS, Vujaskovic, Z, Spasojevic, I, and Batinic-Haberle, I. "Design, mechanism of action, bioavailability and therapeutic effects of mn porphyrin-based redox modulators." Med Princ Pract 22.2 (2013): 103-130. (Review)
PMID
23075911
Source
pubmed
Published In
Medical principles and practice : international journal of the Kuwait University, Health Science Centre
Volume
22
Issue
2
Publish Date
2013
Start Page
103
End Page
130
DOI
10.1159/000341715

Peroxynitrite formation in nitric oxide-exposed submitochondrial particles: Detection, oxidative damage and catalytic removal by Mn-porphyrins

Peroxynitrite (ONOO-) formation in mitochondria may be favored due to the constant supply of superoxide radical (O2-) by the electron transport chain plus the facile diffusion of nitric oxide (NO) to this organelle. Herein, a model system of submitochondrial particles (SMP) in the presence of succinate plus the respiratory inhibitor antimycin A (to increase O2- rates) and the NO-donor NOC-7 was studied to directly establish and quantitate peroxynitrite by a multiplicity of methods including chemiluminescence, fluorescence and immunochemical analysis. While all the tested probes revealed peroxynitrite at near stoichiometric levels with respect to its precursor radicals, coumarin boronic acid (a probe that directly reacts with peroxynitrite) had the more straightforward oxidation profile from O2 - forming SMP as a function of the NO flux. Interestingly, immunospintrapping studies verified protein radical generation in SMP by peroxynitrite. Substrate-supplemented SMP also reduced Mn(III)porphyrins (MnP) to Mn(II)P under physiologically-relevant oxygen levels (3-30 μM); then, Mn(II)P were capable to reduce peroxynitrite and protect SMP from the inhibition of complex I-dependent oxygen consumption and protein radical formation and nitration of membranes. The data directly support the formation of peroxynitrite in mitochondria and demonstrate that MnP can undergo a catalytic redox cycle to neutralize peroxynitrite-dependent mitochondrial oxidative damage. © 2012 Elsevier Inc. All rights reserved.

Authors
Valez, V; Cassina, A; Batinic-Haberle, I; Kalyanaraman, B; Ferrer-Sueta, G; Radi, R
MLA Citation
Valez, V, Cassina, A, Batinic-Haberle, I, Kalyanaraman, B, Ferrer-Sueta, G, and Radi, R. "Peroxynitrite formation in nitric oxide-exposed submitochondrial particles: Detection, oxidative damage and catalytic removal by Mn-porphyrins." Archives of Biochemistry and Biophysics 529.1 (2013): 45-54.
Source
scival
Published In
Archives of Biochemistry and Biophysics
Volume
529
Issue
1
Publish Date
2013
Start Page
45
End Page
54
DOI
10.1016/j.abb.2012.10.012

Experimental radiotherapy Radiation induces aerobic glycolysis through reactive oxygen species

Background and purpose Although radiation induced reoxygenation has been thought to increase radiosensitivity, we have shown that its associated oxidative stress can have radioprotective effects, including stabilization of the transcription factor hypoxia inducible factor 1 (HIF-1). HIF-1 is known to regulate many of the glycolytic enzymes, thereby promoting aerobic glycolysis, which is known to promote treatment resistance. Thus, we hypothesized that reoxygenation after radiation would increase glycolysis. We previously showed that blockade of oxidative stress using a superoxide dismutase (SOD) mimic during reoxygenation can downregulate HIF-1 activity. Here we tested whether concurrent use of this drug with radiotherapy would reduce the switch to a glycolytic phenotype. Materials and methods 40 mice with skin fold window chambers implanted with 4T1 mammary carcinomas were randomized into (1) no treatment, (2) radiation alone, (3) SOD mimic alone, and (4) SOD mimic with concurrent radiation. All mice were imaged on the ninth day following tumor implantation (30 h following radiation treatment) following injection of a fluorescent glucose analog, 2-[N-(7-nitrobenz-2-oxa-1,3-diaxol-4-yl)amino]-2- deoxyglucose (2-NBDG). Hemoglobin saturation was measured by using hyperspectral imaging to quantify oxygenation state. Results Mice treated with radiation showed significantly higher 2-NBDG fluorescence compared to controls (p = 0.007). Hemoglobin saturation analysis demonstrated reoxygenation following radiation, coinciding with the observed increase in glycolysis. The concurrent use of the SOD mimic with radiation demonstrated a significant reduction in 2-NBDG fluorescence compared to effects seen after radiation alone, while having no effect on reoxygenation. Conclusions Radiation induces an increase in tumor glucose demand approximately 30 h following therapy during reoxygenation. The use of an SOD mimic can prevent the increase in aerobic glycolysis when used concurrently with radiation, without preventing reoxygenation. © 2013 Elsevier Ireland Ltd. All rights reserved.

Authors
Zhong, J; Rajaram, N; Brizel, DM; Frees, AE; Ramanujam, N; Batinic-Haberle, I; Dewhirst, MW
MLA Citation
Zhong, J, Rajaram, N, Brizel, DM, Frees, AE, Ramanujam, N, Batinic-Haberle, I, and Dewhirst, MW. "Experimental radiotherapy Radiation induces aerobic glycolysis through reactive oxygen species." Radiotherapy and Oncology 106.3 (2013): 390-396.
Source
scival
Published In
Radiotherapy & Oncology
Volume
106
Issue
3
Publish Date
2013
Start Page
390
End Page
396
DOI
10.1016/j.radonc.2013.02.013

Mn porphyrins as novel molecular magnetic resonance imaging contrast agents.

BACKGROUND AND PURPOSE: In this study, we investigated the potential of a new class of therapeutic Mn porphyrins as molecular MRI probes for prostate cancer imaging. Two compounds of different bioavailibility were investigated: Mn(III) meso-tetrakis(N-ethylpyridinium-2-yl)porphyrin (MnTE-2-PyP(5+)) and Mn(III) meso-tetrakis(N-n-hexylpyridinium-2-yl)porphyrin (MnTnHex-2-PyP(5+)). These compounds have previously been shown to have adjunctive antineoplastic activity through their actions as powerful superoxide dismutase mimics, peroxynitrite scavengers, and modulators of cellular redox-based signaling pathways. Strong paramagnetic MRI contrast properties and affinity for cancer cells suggest their potential application as novel diagnostic imaging agents. MATERIALS AND METHODS: MRI experiments were performed at 7.0T on a Bruker Biospec horizontal bore scanner. All in-vivo experiments were performed on 12 C57 black mice implanted with RM-9 prostate cancer cells on the hind limb. Two mg/kg of MnTnHex-2-PyP(5+) (n=6) and 8 mg/kg MnTE-2-PyP(5+) (n=6) were administered intraperitoneally 90 minutes before imaging. All the images were collected using a volume coil and processed using Paravision 4.0. RESULTS: Phantom studies reveal remarkably high T1 relaxivity changes for both metalloporphyrins, which are twofold to threefold higher than commercially available gadolinium chelates. Observable detection limits using conventional T1-weighted MRI are in the low micromolar range for both compounds. In vivo, MR relaxation changes in prostate tumor xenografts were readily observed after a single injection of either MnTE-2-PyP(5+)or MnTnHex-2-PyP(5+), with tumor contrast to background ratio greatest after MnTE-2-PyP(5+) administration. CONCLUSION: After a single dose of MnTE-2-PyP(5+), contrast changes in prostate tumors are up to sixfold greater than in surrounding, noncancerous tissues, suggesting the potential use of this metalloporphyrin as a novel diagnostic probe for detecting prostate malignancy using MRI.

Authors
Mouraviev, V; Venkatraman, TN; Tovmasyan, A; Kimura, M; Tsivian, M; Mouravieva, V; Polascik, TJ; Wang, H; Amrhein, TJ; Batinic-Haberle, I; Lascola, C
MLA Citation
Mouraviev, V, Venkatraman, TN, Tovmasyan, A, Kimura, M, Tsivian, M, Mouravieva, V, Polascik, TJ, Wang, H, Amrhein, TJ, Batinic-Haberle, I, and Lascola, C. "Mn porphyrins as novel molecular magnetic resonance imaging contrast agents." J Endourol 26.11 (November 2012): 1420-1424.
PMID
22783812
Source
pubmed
Published In
Journal of Endourology
Volume
26
Issue
11
Publish Date
2012
Start Page
1420
End Page
1424
DOI
10.1089/end.2012.0171

Detailed mechanism of the autoxidation of N-hydroxyurea catalyzed by a superoxide dismutase mimic Mn(III) porphyrin: formation of the nitrosylated Mn(II) porphyrin as an intermediate.

The in vitro autoxidation of N-hydroxyurea (HU) is catalyzed by Mn(III)TTEG-2-PyP(5+), a synthetic water soluble Mn(III) porphyrin which is also a potent mimic of the enzyme superoxide dismutase. The detailed mechanism of the reaction is deduced from kinetic studies under basic conditions mostly based on data measured at pH = 11.7 but also including some pH-dependent observations in the pH range 9-13. The major intermediates were identified by UV-vis spectroscopy and electrospray ionization mass spectrometry. The reaction starts with a fast axial coordination of HU to the metal center of Mn(III)TTEG-2-PyP(5+), which is followed by a ligand-to-metal electron transfer to get Mn(II)TTEG-2-PyP(4+) and the free radical derived from HU (HU˙). Nitric oxide (NO) and nitroxyl (HNO) are minor intermediates. The major pathway for the formation of the most significant intermediate, the {MnNO} complex of Mn(II)TTEG-2-PyP(4+), is the reaction of Mn(II)TTEG-2-PyP(4+) with NO. We have confirmed that the autoxidation of the intermediates opens alternative reaction channels, and the process finally yields NO(2)(-) and the initial Mn(III)TTEG-2-PyP(5+). The photochemical release of NO from the {MnNO} intermediate was also studied. Kinetic simulations were performed to validate the deduced rate constants. The investigated reaction has medical implications: the accelerated production of NO and HNO from HU may be utilized for therapeutic purposes.

Authors
Kalmár, J; Biri, B; Lente, G; Bányai, I; Budimir, A; Biruš, M; Batinić-Haberle, I; Fábián, I
MLA Citation
Kalmár, J, Biri, B, Lente, G, Bányai, I, Budimir, A, Biruš, M, Batinić-Haberle, I, and Fábián, I. "Detailed mechanism of the autoxidation of N-hydroxyurea catalyzed by a superoxide dismutase mimic Mn(III) porphyrin: formation of the nitrosylated Mn(II) porphyrin as an intermediate." Dalton Trans 41.38 (October 14, 2012): 11875-11884.
PMID
22911446
Source
pubmed
Published In
Dalton Transactions
Volume
41
Issue
38
Publish Date
2012
Start Page
11875
End Page
11884
DOI
10.1039/c2dt31200j

XIAP inhibition and generation of reactive oxygen species enhances TRAIL sensitivity in inflammatory breast cancer cells.

We recently identified superoxide dismutase (SOD) overexpression and decreased induction of reactive oxygen species (ROS)-mediated apoptosis in models of inflammatory breast cancer (IBC) cells with acquired therapeutic resistance. This population of cells has high expression of X-linked inhibitor of apoptosis protein (XIAP), which inhibits both extrinsic and intrinsic apoptosis pathways. We therefore wanted to evaluate the effect of classical apoptosis-inducing agent TRAIL, a proapoptotic receptor agonist that selectively triggers death receptor (DR)-mediated apoptosis in cancer cells, in the IBC acquired resistance model. XIAP levels and subsequent inhibition of caspase activity inversely correlated with TRAIL sensitivity in our models of IBC. These include SUM149, a basal-type cell line isolated from primary IBC tumors and isogenic SUM149-derived lines rSUM149 and SUM149 wtXIAP, models of acquired therapeutic resistance with endogenous and exogenous XIAP overexpression, respectively. Inhibition of XIAP function using embelin, a plant-derived cell permeable small molecule, in combination with TRAIL caused a synergistic decrease in cell viability. Embelin treatment resulted in activation of extracellular signal-regulated kinase (ERK)1/2 and ROS accumulation, which correlated with downregulation of antioxidant protein SOD1 and consumption of redox modulator reduced glutathione in the XIAP-overexpressing cells. Simultaneous treatment with an SOD mimic, which protects against ROS accumulation, reversed the decrease in cell viability caused by embelin + TRAIL treatment. Embelin primes IBC cells for TRAIL-mediated apoptosis by its direct action on the anti-caspase activity of XIAP and by shifting the cellular redox balance toward oxidative stress-mediated apoptosis. Thus, ROS modulators represent a novel approach to enhance efficacy of TRAIL-based treatment protocols in IBC.

Authors
Allensworth, JL; Aird, KM; Aldrich, AJ; Batinic-Haberle, I; Devi, GR
MLA Citation
Allensworth, JL, Aird, KM, Aldrich, AJ, Batinic-Haberle, I, and Devi, GR. "XIAP inhibition and generation of reactive oxygen species enhances TRAIL sensitivity in inflammatory breast cancer cells." Mol Cancer Ther 11.7 (July 2012): 1518-1527.
PMID
22508521
Source
pubmed
Published In
Molecular cancer therapeutics
Volume
11
Issue
7
Publish Date
2012
Start Page
1518
End Page
1527
DOI
10.1158/1535-7163.MCT-11-0787

A new SOD mimic, Mn(III) ortho N-butoxyethylpyridylporphyrin, combines superb potency and lipophilicity with low toxicity.

The Mn porphyrins of k(cat)(O(2)(.-)) as high as that of a superoxide dismutase enzyme and of optimized lipophilicity have already been synthesized. Their exceptional in vivo potency is at least in part due to their ability to mimic the site and location of mitochondrial superoxide dismutase, MnSOD. MnTnHex-2-PyP(5+) is the most studied among lipophilic Mn porphyrins. It is of remarkable efficacy in animal models of oxidative stress injuries and particularly in central nervous system diseases. However, when used at high single and multiple doses it becomes toxic. The toxicity of MnTnHex-2-PyP(5+) has been in part attributed to its micellar properties, i.e., the presence of polar cationic nitrogens and hydrophobic alkyl chains. The replacement of a CH(2) group by an oxygen atom in each of the four alkyl chains was meant to disrupt the porphyrin micellar character. When such modification occurs at the end of long alkyl chains, the oxygens become heavily solvated, which leads to a significant drop in the lipophilicity of porphyrin. However, when the oxygen atoms are buried deeper within the long heptyl chains, their excessive solvation is precluded and the lipophilicity preserved. The presence of oxygens and the high lipophilicity bestow the exceptional chemical and physical properties to Mn(III) meso-tetrakis(N-n-butoxyethylpyridinium-2-yl)porphyrin, MnTnBuOE-2-PyP(5+). The high SOD-like activity is preserved and even enhanced: log k(cat)(O(2)(.-))=7.83 vs 7.48 and 7.65 for MnTnHex-2-PyP(5+) and MnTnHep-2-PyP(5+), respectively. MnTnBuOE-2-PyP(5+) was tested in an O(2)(.-) -specific in vivo assay, aerobic growth of SOD-deficient yeast, Saccharomyces cerevisiae, where it was fully protective in the range of 5-30 μM. MnTnHep-2-PyP(5+) was already toxic at 5 μM, and MnTnHex-2-PyP(5+) became toxic at 30 μM. In a mouse toxicity study, MnTnBuOE-2-PyP(5+) was several-fold less toxic than either MnTnHex-2-PyP(5+) or MnTnHep-2-PyP(5+).

Authors
Rajic, Z; Tovmasyan, A; Spasojevic, I; Sheng, H; Lu, M; Li, AM; Gralla, EB; Warner, DS; Benov, L; Batinic-Haberle, I
MLA Citation
Rajic, Z, Tovmasyan, A, Spasojevic, I, Sheng, H, Lu, M, Li, AM, Gralla, EB, Warner, DS, Benov, L, and Batinic-Haberle, I. "A new SOD mimic, Mn(III) ortho N-butoxyethylpyridylporphyrin, combines superb potency and lipophilicity with low toxicity." Free Radic Biol Med 52.9 (May 1, 2012): 1828-1834.
PMID
22336516
Source
pubmed
Published In
Free Radical Biology and Medicine
Volume
52
Issue
9
Publish Date
2012
Start Page
1828
End Page
1834
DOI
10.1016/j.freeradbiomed.2012.02.006

Manganese superoxide dismutase, MnSOD and its mimics.

Increased understanding of the role of mitochondria under physiological and pathological conditions parallels increased exploration of synthetic and natural compounds able to mimic MnSOD - endogenous mitochondrial antioxidant defense essential for the existence of virtually all aerobic organisms from bacteria to humans. This review describes most successful mitochondrially-targeted redox-active compounds, Mn porphyrins and MitoQ(10) in detail, and briefly addresses several other compounds that are either catalysts of O(2)(-) dismutation, or its non-catalytic scavengers, and that reportedly attenuate mitochondrial dysfunction. While not a true catalyst (SOD mimic) of O(2)(-) dismutation, MitoQ(10) oxidizes O(2)(-) to O(2) with a high rate constant. In vivo it is readily reduced to quinol, MitoQH(2), which in turn reduces ONOO(-) to NO(2), producing semiquinone radical that subsequently dismutes to MitoQ(10) and MitoQH(2), completing the "catalytic" cycle. In MitoQ(10), the redox-active unit was coupled via 10-carbon atom alkyl chain to monocationic triphenylphosphonium ion in order to reach the mitochondria. Mn porphyrin-based SOD mimics, however, were designed so that their multiple cationic charge and alkyl chains determine both their remarkable SOD potency and carry them into the mitochondria. Several animal efficacy studies such as skin carcinogenesis and UVB-mediated mtDNA damage, and subcellular distribution studies of Saccharomyces cerevisiae and mouse heart provided unambiguous evidence that Mn porphyrins mimic the site and action of MnSOD, which in turn contributes to their efficacy in numerous in vitro and in vivo models of oxidative stress. Within a class of Mn porphyrins, lipophilic analogs are particularly effective for treating central nervous system injuries where mitochondria play key role. This article is part of a Special Issue entitled: Antioxidants and Antioxidant Treatment in Disease.

Authors
Miriyala, S; Spasojevic, I; Tovmasyan, A; Salvemini, D; Vujaskovic, Z; St Clair, D; Batinic-Haberle, I
MLA Citation
Miriyala, S, Spasojevic, I, Tovmasyan, A, Salvemini, D, Vujaskovic, Z, St Clair, D, and Batinic-Haberle, I. "Manganese superoxide dismutase, MnSOD and its mimics." Biochim Biophys Acta 1822.5 (May 2012): 794-814. (Review)
PMID
22198225
Source
pubmed
Published In
Biochimica et Biophysica Acta: international journal of biochemistry and biophysics
Volume
1822
Issue
5
Publish Date
2012
Start Page
794
End Page
814
DOI
10.1016/j.bbadis.2011.12.002

Manganese superoxide dismutase is a mitochondrial fidelity protein that protects Polγ against UV-induced inactivation.

Manganese superoxide dismutase is a nuclear encoded primary antioxidant enzyme localized exclusively in the mitochondrial matrix. Genotoxic agents, such as ultraviolet (UV) radiation, generates oxidative stress and cause mitochondrial DNA (mtDNA) damage. The mtDNA polymerase (Polγ), a major constituent of nucleoids, is responsible for the replication and repair of the mitochondrial genome. Recent studies suggest that the mitochondria contain fidelity proteins and MnSOD constitutes an integral part of the nucleoid complex. However, it is not known whether or how MnSOD participates in the mitochondrial repair processes. Using skin tissue from C57BL/6 mice exposed to UVB radiation, we demonstrate that MnSOD has a critical role in preventing mtDNA damage by protecting the function of Polγ. Quantitative-PCR analysis shows an increase in mtDNA damage after UVB exposure. Immunofluorescence and immunoblotting studies demonstrate p53 translocation to the mitochondria and interaction with Polγ after UVB exposure. The mtDNA immunoprecipitation assay with Polγ and p53 antibodies in p53(+/+) and p53(-/-) mice demonstrates an interaction between MnSOD, p53 and Polγ. The results suggest that these proteins form a complex for the repair of UVB-associated mtDNA damage. The data also demonstrate that UVB exposure injures the mtDNA D-loop in a p53-dependent manner. Using MnSOD-deficient mice we demonstrate that UVB-induced mtDNA damage is MnSOD dependent. Exposure to UVB results in nitration and inactivation of Polγ, which is prevented by addition of the MnSOD mimetic Mn(III)TE-2-PyP(5+). These results demonstrate for the first time that MnSOD is a fidelity protein that maintains the activity of Polγ by preventing UVB-induced nitration and inactivation of Polγ. The data also demonstrate that MnSOD has a role along with p53 to prevent mtDNA damage.

Authors
Bakthavatchalu, V; Dey, S; Xu, Y; Noel, T; Jungsuwadee, P; Holley, AK; Dhar, SK; Batinic-Haberle, I; St Clair, DK
MLA Citation
Bakthavatchalu, V, Dey, S, Xu, Y, Noel, T, Jungsuwadee, P, Holley, AK, Dhar, SK, Batinic-Haberle, I, and St Clair, DK. "Manganese superoxide dismutase is a mitochondrial fidelity protein that protects Polγ against UV-induced inactivation." Oncogene 31.17 (April 26, 2012): 2129-2139.
PMID
21909133
Source
pubmed
Published In
Oncogene: Including Oncogene Reviews
Volume
31
Issue
17
Publish Date
2012
Start Page
2129
End Page
2139
DOI
10.1038/onc.2011.407

Motor deficits are triggered by reperfusion-reoxygenation injury as diagnosed by MRI and by a mechanism involving oxidants.

The early antecedents of cerebral palsy (CP) are unknown but are suspected to be due to hypoxia-ischemia (H-I). In our rabbit model of CP, the MRI biomarker, apparent diffusion coefficient (ADC) on diffusion-weighted imaging, predicted which fetuses will develop postnatal hypertonia. Surviving H-I fetuses experience reperfusion-reoxygenation but a subpopulation manifested a continued decline of ADC during early reperfusion-reoxygenation, which possibly represented greater brain injury (RepReOx). We hypothesized that oxidative stress in reperfusion-reoxygenation is a critical trigger for postnatal hypertonia. We investigated whether RepReOx predicted postnatal neurobehavior, indicated oxidative stress, and whether targeting antioxidants at RepReOx ameliorated motor deficits, which included testing of a new superoxide dismutase mimic (MnTnHex-2-PyP). Rabbit dams, 79% gestation (E25), were subjected to 40 min uterine ischemia. Fetal brain ADC was followed during H-I, immediate reperfusion-reoxygenation, and 4-72 h after H-I. Endpoints were postnatal neurological outcome at E32, ADC at end of H-I, ADC nadir during H-I and reperfusion-reoxygenation, and area under ADC curve during the first 20 min of reperfusion-reoxygenation. Antioxidants targeting RepReOx were administered before and/or after uterine ischemia. The new MRI-ADC biomarker for RepReOx improved prediction of postnatal hypertonia. Greater superoxide production, mitochondrial injury, and oligodendroglial loss occurred in fetal brains exhibiting RepReOx than in those without. The antioxidants, MnTnHex-2-PyP and Ascorbate and Trolox combination, significantly decreased postnatal motor deficits and extent of RepReOx. The etiological link between early injury and later motor deficits can thus be investigated by MRI, and allows us to distinguish between critical oxidative stress that causes motor deficits and noncritical oxidative stress that does not.

Authors
Drobyshevsky, A; Luo, K; Derrick, M; Yu, L; Du, H; Prasad, PV; Vasquez-Vivar, J; Batinic-Haberle, I; Tan, S
MLA Citation
Drobyshevsky, A, Luo, K, Derrick, M, Yu, L, Du, H, Prasad, PV, Vasquez-Vivar, J, Batinic-Haberle, I, and Tan, S. "Motor deficits are triggered by reperfusion-reoxygenation injury as diagnosed by MRI and by a mechanism involving oxidants." J Neurosci 32.16 (April 18, 2012): 5500-5509.
PMID
22514312
Source
pubmed
Published In
The Journal of neuroscience : the official journal of the Society for Neuroscience
Volume
32
Issue
16
Publish Date
2012
Start Page
5500
End Page
5509
DOI
10.1523/JNEUROSCI.5986-11.2012

Manganese porphyrin, MnTE-2-PyP5+, Acts as a pro-oxidant to potentiate glucocorticoid-induced apoptosis in lymphoma cells.

Using current chemotherapy protocols, over 55% of lymphoma patients fail treatment. Novel agents are needed to improve lymphoma survival. The manganese porphyrin, MnTE-2-PyP(5+), augments glucocorticoid-induced apoptosis in WEHI7.2 murine thymic lymphoma cells, suggesting that it may have potential as a lymphoma therapeutic. However, the mechanism by which MnTE-2-PyP(5+) potentiates glucocorticoid-induced apoptosis is unknown. Previously, we showed that glucocorticoid treatment increases the steady state levels of hydrogen peroxide ([H(2)O(2)](ss)) and oxidizes the redox environment in WEHI7.2 cells. In the current study, we found that when MnTE-2-PyP(5+) is combined with glucocorticoids, it augments dexamethasone-induced oxidative stress however, it does not augment the [H(2)O(2)](ss) levels. The combined treatment depletes GSH, oxidizes the 2GSH:GSSG ratio, and causes protein glutathionylation to a greater extent than glucocorticoid treatment alone. Removal of the glucocorticoid-generated H(2)O(2) or depletion of glutathione by BSO prevents MnTE-2-PyP(5+) from augmenting glucocorticoid-induced apoptosis. In combination with glucocorticoids, MnTE-2-PyP(5+) glutathionylates p65 NF-κB and inhibits NF-κB activity. Inhibition of NF-κB with SN50, an NF- κB inhibitor, enhances glucocorticoid-induced apoptosis to the same extent as MnTE-2-PyP(5+). Taken together, these findings indicate that: 1) H(2)O(2) is important for MnTE-2-PyP(5+) activity; 2) Mn-TE-2-PyP(5+) cycles with GSH; and 3) MnTE-2-PyP(5+) potentiates glucocorticoid-induced apoptosis by glutathionylating and inhibiting critical survival proteins, including NF-κB. In the clinic, over-expression of NF-κB is associated with a poor prognosis in lymphoma. MnTE-2-PyP(5+) may therefore, synergize with glucocorticoids to inhibit NF-κB and improve current treatment.

Authors
Jaramillo, MC; Briehl, MM; Crapo, JD; Batinic-Haberle, I; Tome, ME
MLA Citation
Jaramillo, MC, Briehl, MM, Crapo, JD, Batinic-Haberle, I, and Tome, ME. "Manganese porphyrin, MnTE-2-PyP5+, Acts as a pro-oxidant to potentiate glucocorticoid-induced apoptosis in lymphoma cells." Free Radic Biol Med 52.8 (April 15, 2012): 1272-1284.
PMID
22330065
Source
pubmed
Published In
Free Radical Biology and Medicine
Volume
52
Issue
8
Publish Date
2012
Start Page
1272
End Page
1284
DOI
10.1016/j.freeradbiomed.2012.02.001

ErbB1/2 tyrosine kinase inhibitor mediates oxidative stress-induced apoptosis in inflammatory breast cancer cells.

Overexpression of epidermal growth factor receptors (ErbB) is frequently seen in inflammatory breast cancer (IBC). Treatment with ErbB1/2-targeting agents (lapatinib) mediates tumor apoptosis by downregulating ErbB1/2 phosphorylation and downstream survival signaling. In this study, using carboxy-H(2)DCFDA, DHE, and MitoSOX Red to examine changes in hydrogen peroxide radicals, cytoplasmic and mitochondrial superoxide, respectively, we observed that GW583340 (a lapatinib-analog) increases reactive oxygen species (ROS) in two models of IBC (SUM149, SUM190) that are sensitive to ErbB1/2 blockade. This significant increase in ROS levels was similar to those generated by classical oxidative agents H(2)O(2) and paraquat. In contrast, minimal to basal levels of ROS were measured in a clonal population of GW583340-resistant IBC cells (rSUM149 and rSUM190). The GW583340-resistant IBC cells displayed increased SOD1, SOD2, and glutathione expression, which correlated with decreased sensitivity to the apoptotic-inducing effects of GW583340, H(2)O(2), and paraquat. The ROS increase and cell death in the GW583340-sensitive cells was reversed by simultaneous treatment with a superoxide dismutase (SOD) mimic. Additionally, overcoming the high levels of antioxidants using redox modulators induced apoptosis in the GW583340-resistant cells. Taken together, these data demonstrate a novel mechanism of lapatinib-analog-induced apoptosis and indicate that resistant cells have increased antioxidant potential, which can be overcome by treatment with SOD modulators.

Authors
Aird, KM; Allensworth, JL; Batinic-Haberle, I; Lyerly, HK; Dewhirst, MW; Devi, GR
MLA Citation
Aird, KM, Allensworth, JL, Batinic-Haberle, I, Lyerly, HK, Dewhirst, MW, and Devi, GR. "ErbB1/2 tyrosine kinase inhibitor mediates oxidative stress-induced apoptosis in inflammatory breast cancer cells." Breast Cancer Res Treat 132.1 (February 2012): 109-119.
PMID
21559822
Source
pubmed
Published In
Breast Cancer Research and Treatment
Volume
132
Issue
1
Publish Date
2012
Start Page
109
End Page
119
DOI
10.1007/s10549-011-1568-1

Design of Mn porphyrins for treating oxidative stress injuries and their redox-based regulation of cellular transcriptional activities.

The most efficacious Mn(III) porphyrinic (MnPs) scavengers of reactive species have positive charges close to the Mn site, whereby they afford thermodynamic and electrostatic facilitation for the reaction with negatively charged species such as O (2) (•-) and ONOO(-). Those are Mn(III) meso tetrakis(N-alkylpyridinium-2-yl)porphyrins, more specifically MnTE-2-PyP(5+) (AEOL10113) and MnTnHex-2-PyP(5+) (where alkyls are ethyl and n-hexyl, respectively), and their imidazolium analog, MnTDE-2-ImP(5+) (AEOL10150, Mn(III) meso tetrakis(N,N'-diethylimidazolium-2-yl) porphyrin). The efficacy of MnPs in vivo is determined not only by the compound antioxidant potency, but also by its bioavailability. The former is greatly affected by the lipophilicity, size, structure, and overall shape of the compound. These porphyrins have the ability to both eliminate reactive oxygen species and impact the progression of oxidative stress-dependent signaling events. This will effectively lead to the regulation of redox-dependent transcription factors and the suppression of secondary inflammatory- and oxidative stress-mediated immune responses. We have reported on the inhibition of major transcription factors HIF-1α, AP-1, SP-1, and NF-κB by Mn porphyrins. While the prevailing mechanistic view of the suppression of transcription factors activation is via antioxidative action (presumably in cytosol), the pro-oxidative action of MnPs in suppressing NF-κB activation in nucleus has been substantiated. The magnitude of the effect is dependent upon the electrostatic (porphyrin charges) and thermodynamic factors (porphyrin redox ability). The pro-oxidative action of MnPs has been suggested to contribute at least in part to the in vitro anticancer action of MnTE-2-PyP(5+) in the presence of ascorbate, and in vivo when combined with chemotherapy of lymphoma. Given the remarkable therapeutic potential of metalloporphyrins, future studies are warranted to further our understanding of in vivo action/s of Mn porphyrins, particularly with respect to their subcellular distribution.

Authors
Batinic-Haberle, I; Spasojevic, I; Tse, HM; Tovmasyan, A; Rajic, Z; St Clair, DK; Vujaskovic, Z; Dewhirst, MW; Piganelli, JD
MLA Citation
Batinic-Haberle, I, Spasojevic, I, Tse, HM, Tovmasyan, A, Rajic, Z, St Clair, DK, Vujaskovic, Z, Dewhirst, MW, and Piganelli, JD. "Design of Mn porphyrins for treating oxidative stress injuries and their redox-based regulation of cellular transcriptional activities." Amino Acids 42.1 (January 2012): 95-113. (Review)
PMID
20473774
Source
pubmed
Published In
Amino Acids
Volume
42
Issue
1
Publish Date
2012
Start Page
95
End Page
113
DOI
10.1007/s00726-010-0603-6

Protein damage by photo-activated Zn(II) N-alkylpyridylporphyrins.

Destruction of unwanted cells and tissues in photodynamic therapy (PDT) is achieved by a combination of light, oxygen, and light-sensitive molecules. The advantages of PDT compared to other traditional treatment modalities, and the shortcomings of the currently used photosensitizers, have stimulated the search for new, more efficient photosensitizer candidates. Ability to inflict selective damage to particular proteins through photo-irradiation would significantly advance the design of highly specific photosensitizers. Achieving this objective requires comprehensive knowledge concerning the interactions of the particular photosensitizer with specific targets. Here, we summarize the effects of Zn(II) N-alkylpyridylporphyrin-based photosensitizers on intracellular (metabolic, antioxidant and mitochondrial enzymes) and membrane proteins. We emphasize how the structural modifications of the porphyrin side substituents affect their lipophilicity, which in turn influence their subcellular localization. Thus, Zn(II) N-alkylpyridylporphyrins target particular cellular sites and proteins of interest, and are more efficient than hematoporphyrin D, whose commercial preparation (Photofrin) has been clinically approved for PDT.

Authors
Benov, L; Craik, J; Batinic-Haberle, I
MLA Citation
Benov, L, Craik, J, and Batinic-Haberle, I. "Protein damage by photo-activated Zn(II) N-alkylpyridylporphyrins." Amino Acids 42.1 (January 2012): 117-128. (Review)
PMID
20559672
Source
pubmed
Published In
Amino Acids
Volume
42
Issue
1
Publish Date
2012
Start Page
117
End Page
128
DOI
10.1007/s00726-010-0640-1

Erratum: Design of Mn porphyrins for treating oxidative stress injuries and their redox-based regulation of cellular transcriptional activities (Amino Acids DOI: 10.1007/s00726-010-0603-6)

Authors
Batinic-Haberle, I; Spasojevic, I; Tse, HM; Tovmasyan, A; Rajic, Z; Clair, DKS; Vujaskovic, Z; Dewhirst, MW; Piganelli, JD
MLA Citation
Batinic-Haberle, I, Spasojevic, I, Tse, HM, Tovmasyan, A, Rajic, Z, Clair, DKS, Vujaskovic, Z, Dewhirst, MW, and Piganelli, JD. "Erratum: Design of Mn porphyrins for treating oxidative stress injuries and their redox-based regulation of cellular transcriptional activities (Amino Acids DOI: 10.1007/s00726-010-0603-6)." Amino Acids 42.1 (2012): 115-116.
Source
scival
Published In
Amino Acids
Volume
42
Issue
1
Publish Date
2012
Start Page
115
End Page
116
DOI
10.1007/s00726-010-0821-y

Amelioration of renal ischemia-reperfusion injury with a novel protective cocktail.

PURPOSE: Extended warm ischemia during partial nephrectomy can lead to considerable renal injury. Using a rat model of renal ischemia we examined the ability of a unique renoprotective cocktail to ameliorate warm ischemia-reperfusion injury. MATERIALS AND METHODS: A warm renal ischemia model was developed using 60 Sprague-Dawley® rats. The left renal artery was clamped for 40 minutes, followed by 48 hours of reperfusion. A renoprotective cocktail of a mixture of specific growth factors, mitochondria protecting biochemicals and Manganese-Porphyrin (MnTnHex-2-PyP(5+)) was given intramuscularly at -24, 0 and 24 hours after surgery. At 48 hours the 2 kidneys were harvested and examined with hematoxylin and eosin, and periodic acid-Schiff stains. Protein and gene expression were also analyzed to determine ischemia markers and the antioxidant response. RESULTS: Compared to ischemic controls, kidneys treated with the renoprotective cocktail showed significant reversal of morphological changes and a significant decrease in the specific ischemic markers lipocalin-2, mucin-1 and galectin-3. Quantitative reverse transcriptase-polymerase chain reaction revealed up-regulation of several antioxidant genes in treated animals. CONCLUSIONS: According to histopathological and several molecular measures our unique renoprotective cocktail mitigated ischemia-reperfusion injury.

Authors
Dorai, T; Fishman, AI; Ding, C; Batinic-Haberle, I; Goldfarb, DS; Grasso, M
MLA Citation
Dorai, T, Fishman, AI, Ding, C, Batinic-Haberle, I, Goldfarb, DS, and Grasso, M. "Amelioration of renal ischemia-reperfusion injury with a novel protective cocktail." J Urol 186.6 (December 2011): 2448-2454.
PMID
22019164
Source
pubmed
Published In
The Journal of Urology
Volume
186
Issue
6
Publish Date
2011
Start Page
2448
End Page
2454
DOI
10.1016/j.juro.2011.08.010

Mn-Porphyrins as Novel Molecular MRI Contrast Agents.

Introduction: In these experiments, we investigated a new class of therapeutic metalloporphyrins and their potential as molecular MR imaging probes for prostate cancer (PCa). Mn(III)TE-2-Pyp5+ (meso-tetrakis(N-ethyl-2-prydil)porphyrin) and Mn(III)TnHex-2-PYP5+ (meso-tetrakis(N-n-hexyl-2-pyridyl)porphyrin are powerful superoxide dismutase mimics with low toxicity and antineoplastic activity. Methods: MR imaging experiments were performed at 7.0T on a Bruker Biospec horizontal bore scanner. All in vivo experiments were performed on twelve C57 black mice implanted with RM-9 PCa cells on the hind-limb location. 10 mg/kg of MnTn-Hex-2-PyP (n=6) and 2 mg/kg MnTE-2-PyP (n=6) were administered intraperitoneally 60 and 120 minutes prior to imaging. All the images were collected using a volume coil and processed using Paravision 4.0. Results: Phantom studies reveal remarkably high T1 relaxivity changes for both hexyl and ethyl analogues, which are several-fold higher than commercially available gadolinium chelates. Observable detection limits were in the low micromolar range, 1-2 orders of magnitude lower than conventional chelates. In vivo, we readily observed MR relaxation changes in prostate tumor xenografts after a single injection of either ethyl and hexyl analogues, although T1 shortening was highest after hexyl administration. Conclusion: Following a single dose of Mn-Porphyrins, relaxation changes in prostate tumors measured 10-11 folds greater than in surrounding tissues, suggesting these probes may be particularly effective in imaging PCa foci in vivo.

Authors
Mouraviev, V; Kimura, M; Venkatraman, T; Tsivian, M; Mouravieva, V; Batinic Haberle, I; Polascik, TJ; Wang, H; Lascola, C
MLA Citation
Mouraviev, V, Kimura, M, Venkatraman, T, Tsivian, M, Mouravieva, V, Batinic Haberle, I, Polascik, TJ, Wang, H, and Lascola, C. "Mn-Porphyrins as Novel Molecular MRI Contrast Agents." Journal of endourology / Endourological Society (November 2011). (Academic Article)
PMID
22050509
Source
manual
Published In
Journal of Endourology
Publish Date
2011
DOI
10.1089/end.2011.0133

Cytotoxic effects of Mn(III) N-alkylpyridylporphyrins in the presence of cellular reductant, ascorbate.

Due to the ability to easily accept and donate electrons Mn(III)N-alkylpyridylporphyrins (MnPs) can dismute O(2)(·-), reduce peroxynitrite, but also generate reactive species and behave as pro-oxidants if conditions favour such action. Herein two ortho isomers, MnTE-2-PyP(5+), MnTnHex-2-PyP(5+), and a meta isomer MnTnHex-3-PyP(5+), which differ greatly with regard to their metal-centered reduction potential, E(1/2) (Mn(III)P/Mn(II)P) and lipophilicity, were explored. Employing Mn(III)P/Mn(II)P redox system for coupling with ascorbate, these MnPs catalyze ascorbate oxidation and thus peroxide production. Consequently, cancer oxidative burden may be enhanced, which in turn would suppress its growth. Cytotoxic effects on Caco-2, Hela, 4T1, HCT116 and SUM149 were studied. When combined with ascorbate, MnPs killed cancer cells via peroxide produced outside of the cell. MnTE-2-PyP(5+) was the most efficacious catalyst for peroxide production, while MnTnHex-3-PyP(5+) is most prone to oxidative degradation with H(2) , and thus the least efficacious. A 4T1 breast cancer mouse study of limited scope and success was conducted. The tumour oxidative stress was enhanced and its microvessel density reduced when mice were treated either with ascorbate or MnP/ascorbate; the trend towards tumour growth suppression was detected.

Authors
Ye, X; Fels, D; Tovmasyan, A; Aird, KM; Dedeugd, C; Allensworth, JL; Kos, I; Park, W; Spasojevic, I; Devi, GR; Dewhirst, MW; Leong, KW; Batinic-Haberle, I
MLA Citation
Ye, X, Fels, D, Tovmasyan, A, Aird, KM, Dedeugd, C, Allensworth, JL, Kos, I, Park, W, Spasojevic, I, Devi, GR, Dewhirst, MW, Leong, KW, and Batinic-Haberle, I. "Cytotoxic effects of Mn(III) N-alkylpyridylporphyrins in the presence of cellular reductant, ascorbate." Free Radic Res 45.11-12 (November 2011): 1289-1306.
PMID
21859376
Source
pubmed
Published In
Free Radical Research (Informa)
Volume
45
Issue
11-12
Publish Date
2011
Start Page
1289
End Page
1306
DOI
10.3109/10715762.2011.616199

Manganese porphyrin reduces retinal injury induced by ocular hypertension in rats.

This study aimed to clarify the possible therapeutic benefit of preferential nitric oxide synthase (NOS) inhibition and catalytic antioxidant Mn (III) meso-tetrakis (N-n-hexylpyridinium-2-yl) porphyrin (MnTnHex-2-PyP(5+)) treatment in a rat model of elevated intraocular pressure (EIOP). Rats were randomly divided into different experimental groups which received either intraperitoneal MnTnHex-2-PyP(5+) (0.1 mg/kg/day), intragastric NOS inhibitor (S-methylthiourea: SMT; 5 mg/kg/day) or both agents for a period of 6 weeks. Ocular hypertension was induced by unilaterally cauterizing three episcleral vessels and the unoperated eye served as control. Neuroprotective effects of given treatments were determined via electrophysiological measurements of visual evoked potentials (VEP) while retina and vitreous levels of MnTnHex-2-PyP(5+) were measured via LC-MS/MS. Latencies of all VEP components (P(1), N(1), P(2), N(2), P(3)) were significantly prolonged (p < 0.05) in EIOP and returned to control levels following all three treatment protocols. Ocular hypertension significantly increased retinal protein nitration (p < 0.001) which returned to baseline levels in all treated groups. NOS-2 expression and nitrate/nitrite levels were significantly greater in non-treated rats with EIOP. Retinal TUNEL staining showed apoptosis in all ocular hypertensive rats. The presented data confirm the role of oxidative injury in EIOP and highlight the protective effect of MnTnHex-2-PyP(5+) treatment and NOS inhibition in ocular hypertension.

Authors
Dogan, S; Unal, M; Ozturk, N; Yargicoglu, P; Cort, A; Spasojevic, I; Batinic-Haberle, I; Aslan, M
MLA Citation
Dogan, S, Unal, M, Ozturk, N, Yargicoglu, P, Cort, A, Spasojevic, I, Batinic-Haberle, I, and Aslan, M. "Manganese porphyrin reduces retinal injury induced by ocular hypertension in rats." Exp Eye Res 93.4 (October 2011): 387-396.
PMID
21669199
Source
pubmed
Published In
Experimental Eye Research
Volume
93
Issue
4
Publish Date
2011
Start Page
387
End Page
396
DOI
10.1016/j.exer.2011.05.008

Diverse functions of cationic Mn(III) N-substituted pyridylporphyrins, recognized as SOD mimics.

Oxidative stress, a redox imbalance between the endogenous reactive species and antioxidant systems, is common to numerous pathological conditions such as cancer, central nervous system injuries, radiation injury, diabetes etc. Therefore, compounds able to reduce oxidative stress have been actively sought for over 3 decades. Superoxide is the major species involved in oxidative stress either in its own right or through its progeny, such as ONOO⁻, H₂O₂, •OH, CO₃•⁻, and •NO₂. Hence, the very first compounds developed in the late 1970-ies were the superoxide dismutase (SOD) mimics. Thus far the most potent mimics have been the cationic meso Mn(III) N-substituted pyridylporphyrins and N,N'-disubstituted imidazolylporphyrins (MnPs), some of them with k(cat)(O₂·⁻) similar to the k(cat) of SOD enzymes. Most frequently studied are ortho isomers MnTE-2-PyP⁵⁺, MnTnHex-2-PyP⁵⁺, and MnTDE-2-ImP⁵⁺. The ability to disproportionate O₂·⁻ parallels their ability to remove the other major oxidizing species, peroxynitrite, ONOO⁻. The same structural feature that gives rise to the high k(cat)(O₂·⁻) and k(red)(ONOO⁻), allows MnPs to strongly impact the activation of the redox-sensitive transcription factors, HIF-1α, NF-κB, AP-1, and SP-1, and therefore modify the excessive inflammatory and immune responses. Coupling with cellular reductants and other redox-active endogenous proteins seems to be involved in the actions of Mn porphyrins. While hydrophilic analogues, such as MnTE-2-PyP⁵⁺ and MnTDE-2-ImP⁵⁺ are potent in numerous animal models of diseases, the lipophilic analogues, such as MnTnHex-2-PyP⁵⁺, were developed to cross blood brain barrier and target central nervous system and critical cellular compartments, mitochondria. The modification of its structure, aimed to preserve the SOD-like potency and lipophilicity, and diminish the toxicity, has presently been pursued. The pulmonary radioprotection by MnTnHex-2-PyP⁵⁺ was the first efficacy study performed successfully with non-human primates. The Phase I toxicity clinical trials were done on amyotrophic lateral sclerosis patients with N,N'-diethylimidazolium analogue, MnTDE-2-ImP⁵⁺ (AEOL10150). Its aggressive development as a wide spectrum radioprotector by Aeolus Pharmaceuticals has been supported by USA Federal government. The latest generation of compounds, bearing oxygens in pyridyl substituents is presently under aggressive development for cancer and CNS injuries at Duke University and is supported by Duke Translational Research Institute, The Wallace H. Coulter Translational Partners Grant Program, Preston Robert Tisch Brain Tumor Center at Duke, and National Institute of Allergy and Infectious Diseases. Metal center of cationic MnPs easily accepts and donates electrons as exemplified in the catalysis of O₂·⁻ dismutation. Thus such compounds may be equally good anti- and pro-oxidants; in either case the beneficial therapeutic effects may be observed. Moreover, while the in vivo effects may appear antioxidative, the mechanism of action of MnPs that produced such effects may be pro-oxidative; the most obvious example being the inhibition of NF-κB. The experimental data therefore teach us that we need to distinguish between the mechanism/s of action/s of MnPs and the effects we observe. A number of factors impact the type of action of MnPs leading to favorable therapeutic effects: levels of reactive species and oxygen, levels of endogenous antioxidants (enzymes and low-molecular compounds), levels of MnPs, their site of accumulation, and the mutual encounters of all of those species. The complexity of in vivo redox systems and the complex redox chemistry of MnPs challenge and motivate us to further our understanding of the physiology of the normal and diseased cell with ultimate goal to successfully treat human diseases.

Authors
Batinic-Haberle, I; Rajic, Z; Tovmasyan, A; Reboucas, JS; Ye, X; Leong, KW; Dewhirst, MW; Vujaskovic, Z; Benov, L; Spasojevic, I
MLA Citation
Batinic-Haberle, I, Rajic, Z, Tovmasyan, A, Reboucas, JS, Ye, X, Leong, KW, Dewhirst, MW, Vujaskovic, Z, Benov, L, and Spasojevic, I. "Diverse functions of cationic Mn(III) N-substituted pyridylporphyrins, recognized as SOD mimics." Free Radic Biol Med 51.5 (September 1, 2011): 1035-1053. (Review)
PMID
21616142
Source
pubmed
Published In
Free Radical Biology and Medicine
Volume
51
Issue
5
Publish Date
2011
Start Page
1035
End Page
1053
DOI
10.1016/j.freeradbiomed.2011.04.046

Neuroprotective efficacy from a lipophilic redox-modulating Mn(III) N-Hexylpyridylporphyrin, MnTnHex-2-PyP: rodent models of ischemic stroke and subarachnoid hemorrhage.

Intracerebroventricular treatment with redox-regulating Mn(III) N-hexylpyridylporphyrin (MnPorphyrin) is remarkably efficacious in experimental central nervous system (CNS) injury. Clinical development has been arrested because of poor blood-brain barrier penetration. Mn(III) meso-tetrakis (N-hexylpyridinium-2-yl) porphyrin (MnTnHex-2-PyP) was synthesized to include four six-carbon (hexyl) side chains on the core MnPorphyrin structure. This has been shown to increase in vitro lipophilicity 13,500-fold relative to the hydrophilic ethyl analog Mn(III) meso-tetrakis(N-ethylpyridinium-2-yl)porphyrin (MnTE-2-PyP). In normal mice, we found brain MnTnHex-2-PyP accumulation to be ∼9-fold greater than MnTE-2-PyP 24 h after a single intraperitoneal dose. We then evaluated MnTnHex-2-PyP efficacy in outcome-oriented models of focal cerebral ischemia and subarachnoid hemorrhage. For focal ischemia, rats underwent 90-min middle cerebral artery occlusion. Parenteral MnTnHex-2-PyP treatment began 5 min or 6 h after reperfusion onset and continued for 7 days. Neurologic function was improved with both early (P = 0.002) and delayed (P = 0.002) treatment onset. Total infarct size was decreased with both early (P = 0.03) and delayed (P = 0.01) treatment. MnTnHex-2-PyP attenuated nuclear factor κB nuclear DNA binding activity and suppressed tumor necrosis factor-α and interleukin-6 expression. For subarachnoid hemorrhage, mice underwent perforation of the anterior cerebral artery and were treated with intraperitoneal MnTnHex-2-PyP or vehicle for 3 days. Neurologic function was improved (P = 0.02), and vasoconstriction of the anterior cerebral (P = 0.0005), middle cerebral (P = 0.003), and internal carotid (P = 0.015) arteries was decreased by MnTnHex-2-PyP. Side-chain elongation preserved MnPorphyrin redox activity, but improved CNS bioavailability sufficient to cause improved outcome from acute CNS injury, despite delay in parenteral treatment onset of up to 6 h. This advance now allows consideration of MnPorphyrins for treatment of cerebrovascular disease.

Authors
Sheng, H; Spasojevic, I; Tse, HM; Jung, JY; Hong, J; Zhang, Z; Piganelli, JD; Batinic-Haberle, I; Warner, DS
MLA Citation
Sheng, H, Spasojevic, I, Tse, HM, Jung, JY, Hong, J, Zhang, Z, Piganelli, JD, Batinic-Haberle, I, and Warner, DS. "Neuroprotective efficacy from a lipophilic redox-modulating Mn(III) N-Hexylpyridylporphyrin, MnTnHex-2-PyP: rodent models of ischemic stroke and subarachnoid hemorrhage." J Pharmacol Exp Ther 338.3 (September 2011): 906-916.
PMID
21652782
Source
pubmed
Published In
The Journal of pharmacology and experimental therapeutics
Volume
338
Issue
3
Publish Date
2011
Start Page
906
End Page
916
DOI
10.1124/jpet.110.176701

Mn(III) meso-tetrakis-(N-ethylpyridinium-2-yl) porphyrin mitigates total body irradiation-induced long-term bone marrow suppression.

Our recent studies showed that total body irradiation (TBI) induces long-term bone marrow (BM) suppression in part by induction of hematopoietic stem cell (HSC) senescence through reactive oxygen species (ROS). In this study, we examined if Mn(III) meso-tetrakis-(N-ethylpyridinium-2-yl) porphyrin (MnTE), a superoxide dismutase mimetic and potent antioxidant, can mitigate TBI-induced long-term BM injury in a mouse model. Our results showed that post-TBI treatment with MnTE significantly inhibited the increases in ROS production and DNA damage in HSCs and the reduction in HSC frequency and clonogenic function induced by TBI. In fact, the clonogenic function of HSCs from irradiated mice after MnTE treatment was comparable to that of HSCs from normal controls on a per-HSC basis, suggesting that MnTE treatment inhibited the induction of HSC senescence by TBI. This suggestion is supported by the finding that MnTE treatment also reduced the expression of p16(Ink4a) (p16) mRNA in HSCs induced by TBI and improved the long-term and multilineage engraftment of irradiated HSCs after transplantation. Therefore, the results from this study demonstrate that MnTE has the potential to be used as a therapeutic agent to mitigate TBI-induced long-term BM suppression by inhibiting ionizing radiation-induced HSC senescence through the ROS-p16 pathway.

Authors
Li, H; Wang, Y; Pazhanisamy, SK; Shao, L; Batinic-Haberle, I; Meng, A; Zhou, D
MLA Citation
Li, H, Wang, Y, Pazhanisamy, SK, Shao, L, Batinic-Haberle, I, Meng, A, and Zhou, D. "Mn(III) meso-tetrakis-(N-ethylpyridinium-2-yl) porphyrin mitigates total body irradiation-induced long-term bone marrow suppression." Free Radic Biol Med 51.1 (July 1, 2011): 30-37.
PMID
21565268
Source
pubmed
Published In
Free Radical Biology and Medicine
Volume
51
Issue
1
Publish Date
2011
Start Page
30
End Page
37
DOI
10.1016/j.freeradbiomed.2011.04.016

Vitamin C and neoplastic diseases

Ascorbic acid, the infamous antioxidant and cofactor of many enzymes, is present in the cell in millimolar, while in plasma and extracellular fluid in micromolar concentrations, as monovalent ascorbate anion. The highest levels of ascorbate are found in the brain, adrenal glands, white blood cells and skeletal muscles. Ascorbate is transported into the cell via two sodium-dependent transporters - SVCT1 and SVCT2 or as dehydroascorbic acid via glucose transporters of the GLUT family. Almost 40 years have passed since the first cancer clinical trials with vitamin C, which showed that patients with ascorbate treatment benefited with enhanced quality and prolongation of life. Further studies led to controversy since they have not corroborated these findings and medical community concluded that vitamin C has no place in the cancer therapy. Finally, evidences from the human physiology, which showed that only intravenously, and not orally, administered ascorbate could be used as anticancer drug, gave new prospective for the role of vitamin C in the cancer treatment.

Authors
Rajić, Z; Perković, I; Batinić-Haberle, I
MLA Citation
Rajić, Z, Perković, I, and Batinić-Haberle, I. "Vitamin C and neoplastic diseases." Farmaceutski Glasnik 67.5 (June 22, 2011): 303-310. (Review)
Source
scopus
Published In
Farmaceutski glasnik
Volume
67
Issue
5
Publish Date
2011
Start Page
303
End Page
310

A combination of two antioxidants (an SOD mimic and ascorbate) produces a pro-oxidative effect forcing Escherichia coli to adapt via induction of oxyR regulon.

Cationic Mn(III) N-alkylpyridyl (MnTalkyl-2(or 3)-PyP(5+)) and N, N'-dialkylimidazolylporphyrins (MnTDalkyl-2-ImP(5+)) have been regarded as the most powerful SOD mimics/peroxynitrite scavengers - i. e. antioxidants. The ethyl-, MnTE-2-PyP(5+) (AEOL10113), and hexylpyridyl-, MnTnHex-2-PyP(5+) and diethylimidazolylporphyrin, MnTDE-2-ImP(5+) (AEOL10150) have been mostly studied in vitro and in vivo. Given the in vivo abundance of cellular reductants, MnPs can couple with them in removing superoxide. Thus, they could be readily reduced from Mn(III)P to Mn(II)P with ascorbate and glutathione, and in a subsequent step reduce either O(2)(.-) (while acting as superoxide reductase) or oxygen (while exerting pro-oxidative action). Moreover, MnPs can catalyze ascorbate oxidation and in turn hydrogen peroxide production. The in vivo type of MnP action (anti- or pro-oxidative) will depend upon the cellular levels of reactive species, endogenous antioxidants, availability of oxygen, ratio of O(2)(.-)- to peroxide-removing systems, redox ability of MnPs and their cellular localization/bioavailibility. To exemplify the switch from an anti- to pro-oxidative action we have explored a very simple and straightforward system - the superoxide-specific aerobic growth of SOD-deficient E. coli. In such a system, cationic MnPs, ortho and meta MnTE-2-(or 3)-PyP(5+) act as powerful SOD mimics. Yet, in the presence of exogenous ascorbate, the SOD mimics catalyze the H(2)O(2) production, causing oxidative damage to both wild and SOD-deficient strains and inhibiting their growth. Catalase added to the medium reversed the effect indicating that H(2)O(2) is a major damaging/signaling species involved in cell growth suppression. The experiments with oxyR- and soxRS-deficient E. coli were conducted to show that E. coli responds to increased oxidative stress exerted by MnP/ascorbate system by induction of oxyR regulon and thus upregulation of antioxidative defenses such as catalases and peroxidases. As anticipated, when catalase was added into medium to remove H(2)O(2), E. coli did not respond with upregulation of its own antioxidant systems.

Authors
Batinic-Haberle, I; Rajic, Z; Benov, L
MLA Citation
Batinic-Haberle, I, Rajic, Z, and Benov, L. "A combination of two antioxidants (an SOD mimic and ascorbate) produces a pro-oxidative effect forcing Escherichia coli to adapt via induction of oxyR regulon." Anticancer Agents Med Chem 11.4 (May 1, 2011): 329-340. (Review)
PMID
21355843
Source
pubmed
Published In
Anti-Cancer Agents in Medicinal Chemistry
Volume
11
Issue
4
Publish Date
2011
Start Page
329
End Page
340

NADPH oxidase inhibition attenuates total body irradiation-induced haematopoietic genomic instability.

Ionising radiation (IR) is a known carcinogen and poses a significant risk to the haematopoietic system for the development of leukaemia in part by induction of genomic instability. Induction of chronic oxidative stress has been assumed to play an important role in mediating the effect of IR on the haematopoietic system. However, there was no direct evidence to support this hypothesis prior to our studies. In our recent studies, we showed that exposure of mice to total body irradiation (TBI) induces persistent oxidative stress selectively in haematopoietic stem cells (HSCs) at least in part via up-regulation of nicotinamide adenine dinucleotide phosphate oxidase (NOX) 4. Now, we found that post-TBI treatment with diphenylene iodonium (DPI), a pan NOX inhibitor, not only significantly reduces TBI-induced increases in reactive oxygen species (ROS) production, oxidative DNA damage and DNA double-strand breaks in HSCs but also dramatically decreases the number of cells with unstable chromosomal aberrations in the clonal progeny of irradiated HSCs. The effects of DPI are comparable to Mn (III) meso-tetrakis (N-ethylpyridinium-2-yl) porphyrin, a superoxide dismutase mimetic and a potent antioxidant. These findings demonstrate that increased production of ROS by NOX in HSCs mediates the induction of haematopoietic genomic instability by IR and that NOX may represent a novel molecular target to inhibit TBI-induced genomic instability.

Authors
Pazhanisamy, SK; Li, H; Wang, Y; Batinic-Haberle, I; Zhou, D
MLA Citation
Pazhanisamy, SK, Li, H, Wang, Y, Batinic-Haberle, I, and Zhou, D. "NADPH oxidase inhibition attenuates total body irradiation-induced haematopoietic genomic instability." Mutagenesis 26.3 (May 2011): 431-435.
PMID
21415439
Source
pubmed
Published In
Mutagenesis
Volume
26
Issue
3
Publish Date
2011
Start Page
431
End Page
435
DOI
10.1093/mutage/ger001

Methoxy-derivatization of alkyl chains increases the in vivo efficacy of cationic Mn porphyrins. Synthesis, characterization, SOD-like activity, and SOD-deficient E. coli study of meta Mn(III) N-methoxyalkylpyridylporphyrins.

Cationic Mn(III) N-alkylpyridylporphyrins (MnPs) are potent SOD mimics and peroxynitrite scavengers and diminish oxidative stress in a variety of animal models of central nervous system (CNS) injuries, cancer, radiation, diabetes, etc. Recently, properties other than antioxidant potency, such as lipophilicity, size, shape, and bulkiness, which influence the bioavailability and the toxicity of MnPs, have been addressed as they affect their in vivo efficacy and therapeutic utility. Porphyrin bearing longer alkyl substituents at pyridyl ring, MnTnHex-2-PyP(5+), is more lipophilic, thus more efficacious in vivo, particularly in CNS injuries, than the shorter alkyl-chained analog, MnTE-2-PyP(5+). Its enhanced lipophilicity allows it to accumulate in mitochondria (relative to cytosol) and to cross the blood-brain barrier to a much higher extent than MnTE-2-PyP(5+). Mn(III) N-alkylpyridylporphyrins of longer alkyl chains, however, bear micellar character, and when used at higher levels, become toxic. Recently we showed that meta isomers are ∼10-fold more lipophilic than ortho species, which enhances their cellular accumulation, and thus reportedly compensates for their somewhat inferior SOD-like activity. Herein, we modified the alkyl chains of the lipophilic meta compound, MnTnHex-3-PyP(5+) via introduction of a methoxy group, to diminish its toxicity (and/or enhance its efficacy), while maintaining high SOD-like activity and lipophilicity. We compared the lipophilic Mn(III) meso-tetrakis(N-(6'-methoxyhexyl)pyridinium-3-yl)porphyrin, MnTMOHex-3-PyP(5+), to a hydrophilic Mn(III) meso-tetrakis(N-(2'-methoxyethyl)pyridinium-3-yl)porphyrin, MnTMOE-3-PyP(5+). The compounds were characterized by uv-vis spectroscopy, mass spectrometry, elemental analysis, electrochemistry, and ability to dismute O(2)˙(-). Also, the lipophilicity was characterized by thin-layer chromatographic retention factor, R(f). The SOD-like activities and metal-centered reduction potentials for the Mn(III)P/Mn(II)P redox couple were similar-to-identical to those of N-alkylpyridyl analogs: log k(cat) = 6.78, and E(1/2) = +68 mV vs. NHE (MnTMOHex-3-PyP(5+)), and log k(cat) = 6.72, and E(1/2) = +64 mV vs. NHE (MnTMOE-3-PyP(5+)). The compounds were tested in a superoxide-specific in vivo model: aerobic growth of SOD-deficient E. coli, JI132. Both MnTMOHex-3-PyP(5+) and MnTMOE-3-PyP(5+) were more efficacious than their alkyl analogs. MnTMOE-3-PyP(5+) is further significantly more efficacious than the most explored compound in vivo, MnTE-2-PyP(5+). Such a beneficial effect of MnTMOE-3-PyP(5+) on diminished toxicity, improved efficacy and transport across the cell wall may originate from the favorable interplay of the size, length of pyridyl substituents, rotational flexibility (the ortho isomer, MnTE-2-PyP(5+), is more rigid, while MnTMOE-3-PyP(5+) is a more flexible meta isomer), bulkiness and presence of oxygen.

Authors
Tovmasyan, AG; Rajic, Z; Spasojevic, I; Reboucas, JS; Chen, X; Salvemini, D; Sheng, H; Warner, DS; Benov, L; Batinic-Haberle, I
MLA Citation
Tovmasyan, AG, Rajic, Z, Spasojevic, I, Reboucas, JS, Chen, X, Salvemini, D, Sheng, H, Warner, DS, Benov, L, and Batinic-Haberle, I. "Methoxy-derivatization of alkyl chains increases the in vivo efficacy of cationic Mn porphyrins. Synthesis, characterization, SOD-like activity, and SOD-deficient E. coli study of meta Mn(III) N-methoxyalkylpyridylporphyrins." Dalton Trans 40.16 (April 28, 2011): 4111-4121.
PMID
21384047
Source
pubmed
Published In
Dalton Transactions
Volume
40
Issue
16
Publish Date
2011
Start Page
4111
End Page
4121
DOI
10.1039/c0dt01321h

2-hydroxyglutarate production, but not dominant negative function, is conferred by glioma-derived NADP-dependent isocitrate dehydrogenase mutations.

BACKGROUND: Gliomas frequently contain mutations in the cytoplasmic NADP(+)-dependent isocitrate dehydrogenase (IDH1) or the mitochondrial NADP(+)-dependent isocitrate dehydrogenase (IDH2). Several different amino acid substitutions recur at either IDH1 R132 or IDH2 R172 in glioma patients. Genetic evidence indicates that these mutations share a common gain of function, but it is unclear whether the shared function is dominant negative activity, neomorphic production of (R)-2-hydroxyglutarate (2HG), or both. METHODOLOGY/PRINCIPAL FINDINGS: We show by coprecipitation that five cancer-derived IDH1 R132 mutants bind IDH1-WT but that three cancer-derived IDH2 R172 mutants exert minimal binding to IDH2-WT. None of the mutants dominant-negatively lower isocitrate dehydrogenase activity at physiological (40 µM) isocitrate concentrations in mammalian cell lysates. In contrast to this, all of these mutants confer 10- to 100-fold higher 2HG production to cells, and glioma tissues containing IDH1 R132 or IDH2 R172 mutations contain high levels of 2HG compared to glioma tissues without IDH mutations (54.4 vs. 0.1 mg 2HG/g protein). CONCLUSIONS: Binding to, or dominant inhibition of, WT IDH1 or IDH2 is not a shared feature of the IDH1 and IDH2 mutations, and thus is not likely to be important in cancer. The fact that the gain of the enzymatic activity to produce 2HG is a shared feature of the IDH1 and IDH2 mutations suggests that this is an important function for these mutants in driving cancer pathogenesis.

Authors
Jin, G; Reitman, ZJ; Spasojevic, I; Batinic-Haberle, I; Yang, J; Schmidt-Kittler, O; Bigner, DD; Yan, H
MLA Citation
Jin, G, Reitman, ZJ, Spasojevic, I, Batinic-Haberle, I, Yang, J, Schmidt-Kittler, O, Bigner, DD, and Yan, H. "2-hydroxyglutarate production, but not dominant negative function, is conferred by glioma-derived NADP-dependent isocitrate dehydrogenase mutations. (Published online)" PLoS One 6.2 (February 4, 2011): e16812-.
PMID
21326614
Source
pubmed
Published In
PloS one
Volume
6
Issue
2
Publish Date
2011
Start Page
e16812
DOI
10.1371/journal.pone.0016812

Cellular redox modulator, ortho Mn(III) meso-tetrakis(N-n-hexylpyridinium-2-yl)porphyrin, MnTnHex-2-PyP(5+) in the treatment of brain tumors.

Despite intensive efforts to improve multimodal treatment of brain tumor, survival remains limited. Current therapy consists of a combination of surgery, irradiation and chemotherapy with predisposition to long-term complications. Identifying novel targeted therapies is therefore at the forefront of brain tumor research. This study explores the utility of a manganese porphyrin in a brain tumor model. The compound used is ortho isomer, mangnese(III) meso-tetrakis(N-n-hexylpyridinium-2-yl)porphyrin, MnTnHex-2-PyP(5+). It is a powerful SOD mimic and peroxynitrite scavenger and a potent modulator of redox-based cellular transcriptional activity, able to suppress excessive immune and inflammatory responses and in turn proliferative pathways. It is further one of the most lipophilic compound among cationic Mn(III) N-alkylpyridylporphyrins, and thus accumulates predominantly in mitochondria relative to cytosol. In mitochondria, MnTnHex-2-PyP(5+) mimics our key antioxidant system, mitochondrial superoxide dismutase, MnSOD, whose overexpression has been widely shown to suppress tumor growth. Importantly, MnTnHex-2-PyP(5+) crosses blood brain barrier in sufficient amounts to demonstrate efficacy in treating CNS injuries. For those reasons we elected to test its effects in inhibiting brain tumor growth. This study is the first report of the antitumor properties of MnTnHex-2-PyP(5+) as a single agent in adult and pediatric glioblastoma multiforme (D-54 MG, D-245 MG, D-256 MG, D-456 MG) and pediatric medulloblastoma (D-341 MED), and is the first case where a redox-able metal complex has been used in glioma therapy. When given subcutaneously to mice bearing subcutaneous and intracranial xenografts, MnTnHex-2-PyP(5+) caused a significant (P ≤ 0.001) growth delay in D 245 MG, D-256 MG, D-341 MED, and D-456 MG tumors. Growth delay for mice bearing subcutaneous xenografts ranged from 3 days in D-54 MG to 34 days in D-341 MED. With mice bearing intracranial xenografts, MnTnHex-2-PyP(5+) increases median survival by 33% in adult glioblastoma multiforme (D-256 MG; p≤ 0.001) and 173% in pediatric medulloblastoma (D-341 MED, <0.001). The beneficial effects of MnTnHex-2-PyP(5+) are presumably achieved either (1) indirectly via elimination of signaling reactive oxygen and nitrogen species (in particular superoxide and peroxynitrite) which in turn would prevent activation of transcription factors; or (2) directly by coupling with cellular reductants and redox-sensitive signaling proteins. The former action is antioxidative while the latter action is presumably pro-oxidative in nature. Our findings suggest that the use of Mn porphyrin-based SOD mimics, and in particular lipophilic analogues such as MnTnHex-2-PyP(5+), is a promising approach for brain tumor therapy.

Authors
Keir, ST; Dewhirst, MW; Kirkpatrick, JP; Bigner, DD; Batinic-Haberle, I
MLA Citation
Keir, ST, Dewhirst, MW, Kirkpatrick, JP, Bigner, DD, and Batinic-Haberle, I. "Cellular redox modulator, ortho Mn(III) meso-tetrakis(N-n-hexylpyridinium-2-yl)porphyrin, MnTnHex-2-PyP(5+) in the treatment of brain tumors." Anticancer Agents Med Chem 11.2 (February 2011): 202-212.
PMID
21291403
Source
pubmed
Published In
Anti-Cancer Agents in Medicinal Chemistry
Volume
11
Issue
2
Publish Date
2011
Start Page
202
End Page
212

Bioavailability of metalloporphyrin-based SOD mimics is greatly influenced by a single charge residing on a Mn site.

In the cell Mn porphyrins (MnPs) likely couple with cellular reductants which results in a drop of total charge from 5+ to 4+ and dramatically increases their lipophilicity by up to three orders of magnitude depending upon the length of alkylpyridyl chains and type of isomer. The effects result from the interplay of solvation, lipophilicit and stericity. Impact of ascorbate on accumulation of MnPs was measured in E. coli and in Balb/C mouse tumours and muscle; for the latter measurements, the LC/ESI-MS/MS method was developed. Accumulation was significantly enhanced when MnPs were co-administered with ascorbate in both prokaryotic and eukaryotic systems. Further, MnTnHex-2-PyP(5+) accumulates 5-fold more in the tumour than in a muscle. Such data increase our understanding of MnPs cellular and sub-cellular accumulation and remarkable in vivo effects. The work is in progress to understand how coupling of MnPs with ascorbate affects their mechanism of action, in particular with respect to cancer therapy.

Authors
Spasojevic, I; Kos, I; Benov, LT; Rajic, Z; Fels, D; Dedeugd, C; Ye, X; Vujaskovic, Z; Reboucas, JS; Leong, KW; Dewhirst, MW; Batinic-Haberle, I
MLA Citation
Spasojevic, I, Kos, I, Benov, LT, Rajic, Z, Fels, D, Dedeugd, C, Ye, X, Vujaskovic, Z, Reboucas, JS, Leong, KW, Dewhirst, MW, and Batinic-Haberle, I. "Bioavailability of metalloporphyrin-based SOD mimics is greatly influenced by a single charge residing on a Mn site." Free Radic Res 45.2 (February 2011): 188-200.
PMID
20942564
Source
pubmed
Published In
Free Radical Research (Informa)
Volume
45
Issue
2
Publish Date
2011
Start Page
188
End Page
200
DOI
10.3109/10715762.2010.522575

The potential of Zn(II) N-alkylpyridylporphyrins for anticancer therapy.

Reactive oxygen species (ROS) are considered to be a main cause for cancer development, but they can also be used for cancer eradication. Because of this dual nature of ROS action, both antioxidant and prooxidant therapeutic agents have been developed and some have shown clinical promise. Selective uptake of porphyrins by malignant cells has for a long time been used for tumor imaging and for targeted delivery of ROS. Redox-active Mn porphyrins can act both as antioxidants and as prooxidants, and may thus be used in anticancer therapy. Porphyrins, which chelate redox inactive metals, for example Zn, demonstrate photo-sensitizing activity and thus can produce singlet oxygen and other reactive oxygen species in cancer cells on irradiation with visible light. Here we review the properties of Zn(II) N-alkylpyridylporphyrin-based photosensitizers, and their ability to damage selected cellular targets.

Authors
Benov, L; Craik, J; Batinic-Haberle, I
MLA Citation
Benov, L, Craik, J, and Batinic-Haberle, I. "The potential of Zn(II) N-alkylpyridylporphyrins for anticancer therapy." Anticancer Agents Med Chem 11.2 (February 2011): 233-241.
PMID
21355847
Source
pubmed
Published In
Anti-Cancer Agents in Medicinal Chemistry
Volume
11
Issue
2
Publish Date
2011
Start Page
233
End Page
241

Editorial: Part II

Authors
Batinić-Haberle, I
MLA Citation
Batinić-Haberle, I. "Editorial: Part II." Anti-Cancer Agents in Medicinal Chemistry 11.4 (2011): 327-328.
Source
scival
Published In
Anti-Cancer Agents in Medicinal Chemistry
Volume
11
Issue
4
Publish Date
2011
Start Page
327
End Page
328

Response to Rosenthal et al.

Authors
Batinic-Haberle, I; Reboucas, JS; Spasojevic, I
MLA Citation
Batinic-Haberle, I, Reboucas, JS, and Spasojevic, I. "Response to Rosenthal et al." Antioxidants and Redox Signaling 14.6 (2011): 1174-1176.
Source
scival
Published In
Antioxidants & Redox Signaling
Volume
14
Issue
6
Publish Date
2011
Start Page
1174
End Page
1176
DOI
10.1089/ars.2010.3758.rs

Editorial

Authors
Batinić-Haberle, I
MLA Citation
Batinić-Haberle, I. "Editorial." Anti-Cancer Agents in Medicinal Chemistry 11.2 (2011): 172-174.
Source
scival
Published In
Anti-Cancer Agents in Medicinal Chemistry
Volume
11
Issue
2
Publish Date
2011
Start Page
172
End Page
174

Vitamin C and neoplastic diseases

Ascorbic acid, the infamous antioxidant and cofactor of many enzymes, is present in the cell in millimolar, while in plasma and extracellular fluid in micromolar concentrations, as monovalent ascorbate anion. The highest levels of ascorbate are found in the brain, adrenal glands, white blood cells and skeletal muscles. Ascorbate is transported into the cell via two sodium-dependent transporters - SVCT1 and SVCT2 or as dehydroascorbic acid via glucose transporters of the GLUT family. Almost 40 years have passed since the first cancer clinical trials with vitamin C, which showed that patients with ascorbate treatment benefited with enhanced quality and prolongation of life. Further studies led to controversy since they have not corroborated these findings and medical community concluded that vitamin C has no place in the cancer therapy. Finally, evidences from the human physiology, which showed that only intravenously, and not orally, administered ascorbate could be used as anticancer drug, gave new prospective for the role of vitamin C in the cancer treatment.

Authors
Rajić, Z; Perković, I; Batinić-Haberle, I
MLA Citation
Rajić, Z, Perković, I, and Batinić-Haberle, I. "Vitamin C and neoplastic diseases." Farmaceutski Glasnik 67.5 (2011): 303-310.
Source
scival
Published In
Farmaceutski glasnik
Volume
67
Issue
5
Publish Date
2011
Start Page
303
End Page
310

Acid-base and electrochemical properties of manganese meso(ortho- and meta-N-ethylpyridyl)porphyrins: potentiometric, spectrophotometric and spectroelectrochemical study of protolytic and redox equilibria.

The difference in electrostatics and reduction potentials between manganese ortho-tetrakis(N-ethylpyridinium-2-yl)porphyrin (MnTE-2-PyP) and manganese meta-tetrakis(N-ethylpyridinium-3-yl)porphyrin (MnTE-3-PyP) is a challenging topic, particularly because of the high likelihood for their clinical development. Hence, a detailed study of the protolytic and electrochemical speciation of Mn(II-IV)TE-2-PyP and Mn(II-IV)TE-3-PyP in a broad pH range has been performed using the combined spectrophotometric and potentiometric methods. The results reveal that in aqueous solutions within the pH range ∼2-13 the following species exist: (H(2)O)Mn(II)TE-m-PyP(4+), (HO)Mn(II)TE-m-PyP(3+), (H(2)O)(2)Mn(III)TE-m-PyP(5+), (HO)(H(2)O)Mn(III)TE-m-PyP(4+), (O)(H(2)O)Mn(III)TE-m-PyP(3+), (O)(H(2)O)Mn(IV)TE-m-PyP(4+) and (O)(HO)Mn(IV)TE-m-PyP(3+) (m = 2, 3). All the protolytic equilibrium constants that include the accessible species as well as the thermodynamic parameters for each particular protolytic equilibrium have been determined. The corresponding formal reduction potentials related to the reduction of the above species and the thermodynamic parameters describing the accessible reduction couples were calculated as well.

Authors
Weitner, T; Budimir, A; Kos, I; Batinić-Haberle, I; Biruš, M
MLA Citation
Weitner, T, Budimir, A, Kos, I, Batinić-Haberle, I, and Biruš, M. "Acid-base and electrochemical properties of manganese meso(ortho- and meta-N-ethylpyridyl)porphyrins: potentiometric, spectrophotometric and spectroelectrochemical study of protolytic and redox equilibria." Dalton Trans 39.48 (December 28, 2010): 11568-11576.
Website
http://hdl.handle.net/10161/4131
PMID
21052598
Source
pubmed
Published In
Dalton Transactions
Volume
39
Issue
48
Publish Date
2010
Start Page
11568
End Page
11576
DOI
10.1039/c0dt00585a

NADPH oxidase-mediated reactive oxygen species production activates hypoxia-inducible factor-1 (HIF-1) via the ERK pathway after hyperthermia treatment.

Hyperthermia (HT) is a strong adjuvant treatment with radiotherapy and chemotherapy because it causes tumor reoxygenation. However, the detailed molecular mechanisms of how HT enhances tumor oxygenation have not been elucidated. Here we report that 1 h of HT activates hypoxia-inducible factor-1 (HIF-1) in tumors and its downstream targets, vascular endothelial growth factor (VEGF) and pyruvate dehydrogenase kinase 1 (PDK1). Consistent with HIF-1 activation and up-regulation of its downstream genes, HT also enhances tumor perfusion/vascularization and decreases oxygen consumption. As a result, tumor hypoxia is reduced after HT, suggesting that these physiological changes contribute to HT-induced tumor reoxygenation. Because HIF-1 is a potent regulator of tumor vascularization and metabolism, our findings suggest that HIF-1 plays a role in HT-induced tumor reoxygenation by transactivating its downstream targets. We demonstrate that NADPH oxidase-mediated reactive oxygen species production, as a mechanism, up-regulates HIF-1 after HT. Furthermore, we determine that this pathway is initiated by increased transcription of NADPH oxidase-1 through the ERK pathway. In conclusion, this study determines that, although HIF-1 is a good therapeutic target, the timing of its inhibition needs to be optimized to achieve the most beneficial outcome when it is combined with other treatments of HT, radiation, and chemotherapy.

Authors
Moon, EJ; Sonveaux, P; Porporato, PE; Danhier, P; Gallez, B; Batinic-Haberle, I; Nien, Y-C; Schroeder, T; Dewhirst, MW
MLA Citation
Moon, EJ, Sonveaux, P, Porporato, PE, Danhier, P, Gallez, B, Batinic-Haberle, I, Nien, Y-C, Schroeder, T, and Dewhirst, MW. "NADPH oxidase-mediated reactive oxygen species production activates hypoxia-inducible factor-1 (HIF-1) via the ERK pathway after hyperthermia treatment." Proc Natl Acad Sci U S A 107.47 (November 23, 2010): 20477-20482.
PMID
21059928
Source
pubmed
Published In
Proceedings of the National Academy of Sciences of USA
Volume
107
Issue
47
Publish Date
2010
Start Page
20477
End Page
20482
DOI
10.1073/pnas.1006646107

Proteomic analysis of radiation-induced changes in rat lung: Modulation by the superoxide dismutase mimetic MnTE-2-PyP(5+).

PURPOSE: To identify temporal changes in protein expression in the irradiated rat lung and generate putative mechanisms underlying the radioprotective effect of the manganese superoxide dismutase mimetic MnTE-2-PyP(5+). METHODS AND MATERIALS: Female Fischer 344 rats were irradiated to the right hemithorax with a single dose of 28 Gy and killed from day 1 to 20 weeks after irradiation. Proteomic profiling was performed to identify proteins that underwent significant changes in abundance. Some irradiated rats were administered MnTE-2-PyP(5+) and changes in protein expression and phosphorylation determined at 6 weeks after irradiation. RESULTS: Radiation induced a biphasic stress response in the lung, as shown by the induction of heme oxygenase 1 at 1-3 days and at 6-8 weeks after irradiation. At 6-8 weeks after irradiation, the down-regulation of proteins involved in cytoskeletal architecture (filamin A and talin), antioxidant defense (biliverdin reductase and peroxiredoxin II), and cell signaling (β-catenin, annexin II, and Rho-guanosine diphosphate dissociation inhibitor) was observed. Treatment with MnTE-2-PyP(5+) partially prevented the apparent degradation of filamin and talin, reduced the level of cleaved caspases 3 and 9, and promoted Akt phosphorylation as well as β-catenin expression. CONCLUSION: A significant down-regulation of proteins and an increase in protein markers of apoptosis were observed at the onset of lung injury in the irradiated rat lung. Treatment with MnTE-2-PyP(5+), which has been demonstrated to reduce lung injury from radiation, reduced apparent protein degradation and apoptosis indicators, suggesting that preservation of lung structural integrity and prevention of cell loss may underlie the radioprotective effect of this compound.

Authors
Yakovlev, VA; Rabender, CS; Sankala, H; Gauter-Fleckenstein, B; Fleckenstein, K; Batinic-Haberle, I; Jackson, I; Vujaskovic, Z; Anscher, MS; Mikkelsen, RB; Graves, PR
MLA Citation
Yakovlev, VA, Rabender, CS, Sankala, H, Gauter-Fleckenstein, B, Fleckenstein, K, Batinic-Haberle, I, Jackson, I, Vujaskovic, Z, Anscher, MS, Mikkelsen, RB, and Graves, PR. "Proteomic analysis of radiation-induced changes in rat lung: Modulation by the superoxide dismutase mimetic MnTE-2-PyP(5+)." Int J Radiat Oncol Biol Phys 78.2 (October 1, 2010): 547-554.
PMID
20584581
Source
pubmed
Published In
International Journal of Radiation: Oncology - Biology - Physics
Volume
78
Issue
2
Publish Date
2010
Start Page
547
End Page
554
DOI
10.1016/j.ijrobp.2010.03.037

Superoxide dismutase mimics: chemistry, pharmacology, and therapeutic potential.

Oxidative stress has become widely viewed as an underlying condition in a number of diseases, such as ischemia-reperfusion disorders, central nervous system disorders, cardiovascular conditions, cancer, and diabetes. Thus, natural and synthetic antioxidants have been actively sought. Superoxide dismutase is a first line of defense against oxidative stress under physiological and pathological conditions. Therefore, the development of therapeutics aimed at mimicking superoxide dismutase was a natural maneuver. Metalloporphyrins, as well as Mn cyclic polyamines, Mn salen derivatives and nitroxides were all originally developed as SOD mimics. The same thermodynamic and electrostatic properties that make them potent SOD mimics may allow them to reduce other reactive species such as peroxynitrite, peroxynitrite-derived CO(3)(*-), peroxyl radical, and less efficiently H(2)O(2). By doing so SOD mimics can decrease both primary and secondary oxidative events, the latter arising from the inhibition of cellular transcriptional activity. To better judge the therapeutic potential and the advantage of one over the other type of compound, comparative studies of different classes of drugs in the same cellular and/or animal models are needed. We here provide a comprehensive overview of the chemical properties and some in vivo effects observed with various classes of compounds with a special emphasis on porphyrin-based compounds.

Authors
Batinić-Haberle, I; Rebouças, JS; Spasojević, I
MLA Citation
Batinić-Haberle, I, Rebouças, JS, and Spasojević, I. "Superoxide dismutase mimics: chemistry, pharmacology, and therapeutic potential." Antioxid Redox Signal 13.6 (September 15, 2010): 877-918. (Review)
Website
http://hdl.handle.net/10161/3344
PMID
20095865
Source
pubmed
Published In
Antioxidants & Redox Signaling
Volume
13
Issue
6
Publish Date
2010
Start Page
877
End Page
918
DOI
10.1089/ars.2009.2876

Water exchange rates of water-soluble manganese(III) porphyrins of therapeutical potential.

The activation parameters and the rate constants of the water-exchange reactions of Mn(III)TE-2-PyP(5+) (meso-tetrakis(N-ethylpyridinium-2-yl)porphyrin) as cationic, Mn(III)TnHex-2-PyP(5+) (meso-tetrakis(N-n-hexylpyridinium-2-yl)porphyrin) as sterically shielded cationic, and Mn(III)TSPP(3-) (meso-tetrakis(4-sulfonatophenyl)porphyrin) as anionic manganese(iii) porphyrins were determined from the temperature dependence of (17)O NMR relaxation rates. The rate constants at 298 K were obtained as 4.12 x 10(6) s(-1), 5.73 x 10(6) s(-1), and 2.74 x 10(7) s(-1), respectively. On the basis of the determined entropies of activation, an interchange-dissociative mechanism (I(d)) was proposed for the cationic complexes (DeltaS(double dagger) = approximately 0 J mol(-1) K(-1)) whereas a limiting dissociative mechanism (D) was proposed for Mn(III)TSPP(3-) complex (DeltaS(double dagger) = +79 J mol(-1) K(-1)). The obtained water exchange rate of Mn(III)TSPP(3-) corresponded well to the previously assumed value used by Koenig et al. (S. H. Koenig, R. D. Brown and M. Spiller, Magn. Reson. Med., 1987, 4, 52-260) to simulate the (1)H NMRD curves, therefore the measured value supports the theory developed for explaining the anomalous relaxivity of Mn(III)TSPP(3-) complex. A magnitude of the obtained water-exchange rate constants further confirms the suggested inner sphere electron transfer mechanism for the reactions of the two positively charged Mn(iii) porphyrins with the various biologically important oxygen and nitrogen reactive species. Due to the high biological and clinical relevance of the reactions that occur at the metal site of the studied Mn(iii) porphyrins, the determination of water exchange rates advanced our insight into their efficacy and mechanism of action, and in turn should impact their further development for both diagnostic (imaging) and therapeutic purposes.

Authors
Budimir, A; Kalmár, J; Fábián, I; Lente, G; Bányai, I; Batinić-Haberle, I; Birus, M
MLA Citation
Budimir, A, Kalmár, J, Fábián, I, Lente, G, Bányai, I, Batinić-Haberle, I, and Birus, M. "Water exchange rates of water-soluble manganese(III) porphyrins of therapeutical potential." Dalton Trans 39.18 (May 14, 2010): 4405-4410.
Website
http://hdl.handle.net/10161/4123
PMID
20422097
Source
pubmed
Published In
Dalton Transactions
Volume
39
Issue
18
Publish Date
2010
Start Page
4405
End Page
4410
DOI
10.1039/b926522h

Early and late administration of MnTE-2-PyP5+ in mitigation and treatment of radiation-induced lung damage.

Chronic production of reactive oxygen and nitrogen species is an underlying mechanism of irradiation (IR)-induced lung injury. The purpose of this study was to determine the optimum time of delivery of an antioxidant and redox-modulating Mn porphyrin, MnTE-2-PyP(5+), to mitigate and/or treat IR-induced lung damage. Female Fischer-344 rats were irradiated to their right hemithorax (28 Gy). Irradiated animals were treated with PBS or MnTE-2-PyP(5+) (6 mg /kg/24 h) delivered for 2 weeks by sc-implanted osmotic pumps (beginning after 2, 6, 12, 24, or 72 h or 8 weeks). Animals were sacrificed 10 weeks post-IR. Endpoints were body weight, breathing frequency, histopathology, and immunohistochemistry (8-OHdG, ED-1, TGF-beta, HIF-1alpha, VEGF A). A significant radioprotective effect on functional injury, measured by breathing frequency, was observed for all animals treated with MnTE-2-PyP(5+). Treatment with MnTE-2-PyP(5+) starting 2, 6, and 12 h but not after 24 or 72 h resulted in a significant decrease in immunostaining for 8-OHdG, HIF-1alpha, TGF-beta, and VEGF A. A significant decrease in HIF-1alpha, TGF-beta, and VEGF A, as well as an overall reduction in lung damage (histopathology), was observed in animals beginning treatment at the time of fully developed lung injury (8 weeks post-IR). The catalytic manganese porphyrin antioxidant and modulator of redox-based signaling pathways MnTE-2-PyP(5+) mitigates radiation-induced lung injury when given within the first 12 h after IR. More importantly, this is the first study to demonstrate that MnTE-2-PyP(5+) can reverse overall lung damage when started at the time of established lung injury 8 weeks post-IR. The radioprotective effects are presumably mediated through its ability both to suppress oxidative stress and to decrease activation of key transcription factors and proangiogenic and profibrogenic cytokines.

Authors
Gauter-Fleckenstein, B; Fleckenstein, K; Owzar, K; Jiang, C; Rebouças, JS; Batinic-Haberle, I; Vujaskovic, Z
MLA Citation
Gauter-Fleckenstein, B, Fleckenstein, K, Owzar, K, Jiang, C, Rebouças, JS, Batinic-Haberle, I, and Vujaskovic, Z. "Early and late administration of MnTE-2-PyP5+ in mitigation and treatment of radiation-induced lung damage." Free Radic Biol Med 48.8 (April 15, 2010): 1034-1043.
PMID
20096348
Source
pubmed
Published In
Free Radical Biology and Medicine
Volume
48
Issue
8
Publish Date
2010
Start Page
1034
End Page
1043
DOI
10.1016/j.freeradbiomed.2010.01.020

Protective role of ortho-substituted Mn(III) N-alkylpyridylporphyrins against the oxidative injury induced by tert-butylhydroperoxide.

The present work addresses the role of two ortho-substituted Mn(III) N-alkylpyridylporphyrins, alkyl being ethyl in MnTE-2-PyP(5+) and n-hexyl in MnTnHex-2-PyP(5+), on the protection against the oxidant tert-butylhydroperoxide (TBHP). Their protective role was studied in V79 cells using endpoints of cell viability (MTT and crystal violet assays), intracellular O(2)*- generation (dihydroethidium assay) and glutathione status (DTNB and monochlorobimane assays). MnPs per se did not show cytotoxicity (up to 25 microM, 24 h). The exposure to TBHP resulted in a significant decrease in cell viability and in an increase in the intracellular O(2)(*-) levels. Also, TBHP depleted total and reduced glutathione and increased GSSG. The two MnPs counteracted remarkably the effects of TBHP. Even at low concentrations, both MnPs were protective in terms of cell viability and abrogated the intracellular O(2)(*-) increase in a significant way. Also, they augmented markedly the total and reduced glutathione contents in TBHP-treated cells, highlighting the multiple mechanisms of protection of these SOD mimics, which at least in part may be ascribed to their electron-donating ability.

Authors
Fernandes, AS; Gaspar, J; Cabral, MF; Rueff, J; Castro, M; Batinic-Haberle, I; Costa, J; Oliveira, NG
MLA Citation
Fernandes, AS, Gaspar, J, Cabral, MF, Rueff, J, Castro, M, Batinic-Haberle, I, Costa, J, and Oliveira, NG. "Protective role of ortho-substituted Mn(III) N-alkylpyridylporphyrins against the oxidative injury induced by tert-butylhydroperoxide." Free Radic Res 44.4 (April 2010): 430-440.
PMID
20102317
Source
pubmed
Published In
Free Radical Research (Informa)
Volume
44
Issue
4
Publish Date
2010
Start Page
430
End Page
440
DOI
10.3109/10715760903555844

Thermodynamics and electrochemistry of manganese ortho-tetrakis(N-n- butylpyridinium-2-yl)porphyrin in aqueous solutions

Spectrophotometric pH-titrations (1 < pH < 12) of manganese ortho-tetrakis(N-n-butylpyridinium-2-yl)porphyrin (MnTnBu-2-PyP) have been performed in aqueous solution at various temperatures and ionic strengths, studying complexes of various manganese oxidation states (Mn(II)-(IV)). The observed results indicate three absorbing species of MnIIITnBu-2-PyP, but only two absorbing species of MnIITnBu-2-PyP and MnIVTnBu-2-PyP within the studied acidity range. The first and second deprotonation constants are related to fully protonated and monodeprotonated species, i.e., the aqua and hydroxo complexes, respectively. The same complexes have been studied by cyclic-voltammetry and the results can be summarized as follows: E0'(MnIIITnBu-2-PyP(H 2O)(OH)4+/MnIITnBu-2-PyP(H2O) 4+) = +0.203 V, E0'(MnIIITnBu-2-PyP(H2O)(OH) 4+/MnIITnBu-2-PyP(OH)3+) = +0.191 V, and E0'(MnIVTnBu-2-PyP(H2O)(OH)5+/Mn IIITnBu-2-PyP(H2O)5+2) = +0.62 V, all versus NHE. In neutral and acidic media the oxidation of the aqua Mn(III) complex may also occur as a one-electron two-proton process yielding the oxoaqua Mn(IV) complex. © 2010 Taylor & Francis.

Authors
Budimir, A; Šmuc, T; Weitner, T; Batinić-Haberle, I; Biruš, M
MLA Citation
Budimir, A, Šmuc, T, Weitner, T, Batinić-Haberle, I, and Biruš, M. "Thermodynamics and electrochemistry of manganese ortho-tetrakis(N-n- butylpyridinium-2-yl)porphyrin in aqueous solutions." Journal of Coordination Chemistry 63.14-16 (2010): 2750-2765.
Source
scival
Published In
Journal of Coordination Chemistry
Volume
63
Issue
14-16
Publish Date
2010
Start Page
2750
End Page
2765
DOI
10.1080/00958972.2010.502571

High lipophilicity of meta Mn(III) N-alkylpyridylporphyrin-based superoxide dismutase mimics compensates for their lower antioxidant potency and makes them as effective as ortho analogues in protecting superoxide dismutase-deficient Escherichia coli.

Lipophilicity/bioavailibility of Mn(III) N-alkylpyridylporphyrin-based superoxide dismutase (SOD) mimics has a major impact on their in vivo ability to suppress oxidative stress. Meta isomers are less potent SOD mimics than ortho analogues but are 10-fold more lipophilic and more planar. Enhanced lipophilicity contributes to their higher accumulation in cytosol of SOD-deficient Escherichia coli, compensating for their lower potency; consequently, both isomers exert similar-to-identical protection of SOD-deficient E. coli. Thus meta isomers may be prospective therapeutics as are ortho porphyrins.

Authors
Kos, I; Benov, L; Spasojević, I; Rebouças, JS; Batinić-Haberle, I
MLA Citation
Kos, I, Benov, L, Spasojević, I, Rebouças, JS, and Batinić-Haberle, I. "High lipophilicity of meta Mn(III) N-alkylpyridylporphyrin-based superoxide dismutase mimics compensates for their lower antioxidant potency and makes them as effective as ortho analogues in protecting superoxide dismutase-deficient Escherichia coli." J Med Chem 52.23 (December 10, 2009): 7868-7872.
PMID
19954250
Source
pubmed
Published In
Journal of Medicinal Chemistry
Volume
52
Issue
23
Publish Date
2009
Start Page
7868
End Page
7872
DOI
10.1021/jm900576g

Determination of residual manganese in Mn porphyrin-based superoxide dismutase (SOD) and peroxynitrite reductase mimics.

The awareness of the beneficial effects of Mn porphyrin-based superoxide dismutase (SOD) mimics and peroxynitrite scavengers on decreasing oxidative stress injuries has increased the use of these compounds as mechanistic probes and potential therapeutics. Simple Mn2+ salts, however, have SOD-like activity in their own right both in vitro and in vivo. Thus, quantification/removal of residual Mn2+ species in Mn-based therapeutics is critical to an unambiguous interpretation of biological data. Herein we report a simple, sensitive, and specific method to determine residual Mn2+ in Mn porphyrin preparations that combines a hydrometallurgical approach for separation/speciation of metal compounds with a spectrophotometric strategy for Mn determination. The method requires only common chemicals and a spectrophotometer and is based on the extraction of residual Mn2+ by bis(2-ethylhexyl)hydrogenphosphate (D2EHPA) into kerosene, re-extraction into acid, and neutralization followed by UV-vis determination of the Mn2+ levels via a Cd2+-catalyzed metallation of the H2TCPP4- porphyrin indicator. The overall procedure is simple, sensitive, specific, and amenable to adaptation. This quantification method has been routinely used by us for a large variety of water-soluble porphyrins.

Authors
Rebouças, JS; Kos, I; Vujasković, Z; Batinić-Haberle, I
MLA Citation
Rebouças, JS, Kos, I, Vujasković, Z, and Batinić-Haberle, I. "Determination of residual manganese in Mn porphyrin-based superoxide dismutase (SOD) and peroxynitrite reductase mimics." J Pharm Biomed Anal 50.5 (December 5, 2009): 1088-1091.
PMID
19660888
Source
pubmed
Published In
Journal of Pharmaceutical and Biomedical Analysis
Volume
50
Issue
5
Publish Date
2009
Start Page
1088
End Page
1091
DOI
10.1016/j.jpba.2009.07.002

Supraspinal inactivation of mitochondrial superoxide dismutase is a source of peroxynitrite in the development of morphine antinociceptive tolerance.

Effective treatment of chronic pain with morphine is limited by decreases in the drug's analgesic action with chronic administration (antinociceptive tolerance). Because opioids are mainstays of pain management, restoring their efficacy has great clinical importance. We have recently reported that formation of peroxynitrite (ONOO(-), PN) in the dorsal horn of the spinal cord plays a critical role in the development of morphine antinociceptive tolerance and have further documented that nitration and enzymatic inactivation of mitochondrial superoxide dismutase (MnSOD) at that site provides a source for this nitroxidative species. We now report for the first time that antinociceptive tolerance in mice is also associated with the inactivation of MnSOD at supraspinal sites. Inactivation of MnSOD led to nitroxidative stress as evidenced by increased levels of products of oxidative DNA damage and activation of the nuclear factor poly (ADP-ribose) polymerase in whole brain homogenates. Co-administration of morphine with potent Mn porphyrin-based peroxynitrite scavengers, Mn(III) 5,10,15,20-tetrakis(N-ethylpyridinium-2-yl)porphyrin (MnTE-2-PyP5+) and Mn(III) 5,10,15,20-tetrakis(N-n-hexylpyridinium-2-yl)porphyrin (MnTnHex-2-PyP5+) (1) restored the enzymatic activity of MnSOD, (2) attenuated PN-derived nitroxidative stress, and (3) blocked the development of morphine-induced antinociceptive tolerance. The more lipophilic analogue, MnTnHex-2-PyP5+ was able to cross the blood-brain barrier at higher levels than its lipophylic counterpart MnTE-2-PyP5+ and was about 30-fold more efficacious. Collectively, these data suggest that PN-mediated enzymatic inactivation of supraspinal MnSOD provides a source of nitroxidative stress, which in turn contributes to central sensitization associated with the development of morphine antinociceptive tolerance. These results support our general contention that PN-targeted therapeutics may have potential as adjuncts to opiates in pain management.

Authors
Doyle, T; Bryant, L; Batinic-Haberle, I; Little, J; Cuzzocrea, S; Masini, E; Spasojevic, I; Salvemini, D
MLA Citation
Doyle, T, Bryant, L, Batinic-Haberle, I, Little, J, Cuzzocrea, S, Masini, E, Spasojevic, I, and Salvemini, D. "Supraspinal inactivation of mitochondrial superoxide dismutase is a source of peroxynitrite in the development of morphine antinociceptive tolerance." Neuroscience 164.2 (December 1, 2009): 702-710.
PMID
19607887
Source
pubmed
Published In
Neuroscience
Volume
164
Issue
2
Publish Date
2009
Start Page
702
End Page
710
DOI
10.1016/j.neuroscience.2009.07.019

Antiangiogenic action of redox-modulating Mn(III) meso-tetrakis(N-ethylpyridinium-2-yl)porphyrin, MnTE-2-PyP(5+), via suppression of oxidative stress in a mouse model of breast tumor.

MnTE-2-PyP(5+) is a potent catalytic scavenger of reactive oxygen and nitrogen species, primarily superoxide and peroxynitrite. It therefore not only attenuates primary oxidative damage, but was found to modulate redox-based signaling pathways (HIF-1alpha, NF-kappaB, SP-1, and AP-1) and thus, in turn, secondary oxidative injury also. Cancer has been widely considered an oxidative stress condition. The goal of this study was to prove if and why a catalytic SOD mimic/peroxynitrite scavenger would exert anti-cancer effects, i.e., to evaluate whether the attenuation of the oxidative stress by MnTE-2-PyP(5+) could suppress tumor growth in a 4T1 mouse breast tumor model. Tumor cells were implanted into Balb/C mouse flanks. Three groups of mice (n=25) were studied: control (PBS) and 2 and 15 mg/kg/day of MnTE-2-PyP(5+) given subcutaneously twice daily starting when the tumors averaged 200 mm(3) (until they reached approximately 5-fold the initial volume). Intratumoral hypoxia (pimonidazole, carbonic anhydrase), HIF-1alpha, VEGF, proliferating capillary index (CD105), microvessel density (CD31), protein nitration, DNA oxidation (8-OHdG), NADPH oxidase (Nox-4), apoptosis (CD31), macrophage infiltration (CD68), and tumor drug levels were assessed. With 2 mg/kg/day a trend toward tumor growth delay was observed, and a significant trend was observed with 15 mg/kg/day. The 7.5-fold increase in drug dose was accompanied by a similar (6-fold) increase in tumor drug levels. Oxidative stress was largely attenuated as observed through the decreased levels of DNA damage, protein 3-nitrotyrosine, macrophage infiltration, and NADPH oxidase. Further, hypoxia was significantly decreased as were the levels of HIF-1alpha and VEGF. Consequently, suppression of angiogenesis was observed; both the microvessel density and the endothelial cell proliferation were markedly decreased. Our study indicates for the first time that MnTE-2-PyP(5+) has anti-cancer activity in its own right. The anti-cancer activity via HIF/VEGF pathways probably arises from the impact of the drug on the oxidative stress. Therefore, the catalytic scavenging of ROS/RNS by antioxidants, which in turn suppresses cellular transcriptional activity, could be an appropriate strategy for anti-cancer therapy. Enhancement of the anti-cancer effects may be achieved by optimizing the dosing regime, utilizing more bioavailable Mn porphyrins (MnP), and combining MnP treatment with irradiation, hyperthermia, and chemotherapy. Mn porphyrins may be advantageous compared to other anti-cancer drugs, owing to their radioprotection of normal tissue and the ability to afford pain management in cancer patients via prevention of chronic morphine tolerance.

Authors
Rabbani, ZN; Spasojevic, I; Zhang, X; Moeller, BJ; Haberle, S; Vasquez-Vivar, J; Dewhirst, MW; Vujaskovic, Z; Batinic-Haberle, I
MLA Citation
Rabbani, ZN, Spasojevic, I, Zhang, X, Moeller, BJ, Haberle, S, Vasquez-Vivar, J, Dewhirst, MW, Vujaskovic, Z, and Batinic-Haberle, I. "Antiangiogenic action of redox-modulating Mn(III) meso-tetrakis(N-ethylpyridinium-2-yl)porphyrin, MnTE-2-PyP(5+), via suppression of oxidative stress in a mouse model of breast tumor." Free Radic Biol Med 47.7 (October 1, 2009): 992-1004.
PMID
19591920
Source
pubmed
Published In
Free Radical Biology and Medicine
Volume
47
Issue
7
Publish Date
2009
Start Page
992
End Page
1004
DOI
10.1016/j.freeradbiomed.2009.07.001

Long-term neuroprotection from a potent redox-modulating metalloporphyrin in the rat.

Sustained oxidative stress is a known sequel to focal cerebral ischemia. This study examined the effects of treatment with a single dose or sustained infusion of the redox-modulating MnPorphyrin Mn(III)TDE-2-ImP(5+) on outcome from middle cerebral artery occlusion (MCAO) in the rat. Normothermic rats were subjected to 90 min MCAO followed by 90 min reperfusion and then were treated with a single intracerebroventricular dose of Mn(III)TDE-2-ImP(5+). Neurologic and histologic outcomes were assessed at 1 or 8 weeks postischemia. A single dose of Mn(III)TDE-2-ImP(5+) caused a dose-dependent improvement in histologic and neurologic outcome when assessed 1 week postischemia. Mn(III)TDE-2-ImP(5+) afforded preservation of brain aconitase activity at 5.5 h after reperfusion onset, consistent with its known antioxidant properties. Mn(III)TDE-2-ImP(5+) also attenuated postischemic NF-kappaB activation. Evidence for effects on cerebral infarct size and neurologic function had completely dissipated when rats were allowed to survive for 8 weeks postischemia. In contrast, a 1-week continuous intracerebroventricular Mn(III)TDE-2-ImP(5+) infusion caused persistent and substantive reduction in both cerebral infarct size and neurologic deficit at 8 weeks postischemia. Pharmacologic modulation of postischemic oxidative stress is likely to require sustained intervention for enduring efficacy in improving neurologic and histologic outcome from a transient focal ischemic insult.

Authors
Sheng, H; Yang, W; Fukuda, S; Tse, HM; Paschen, W; Johnson, K; Batinic-Haberle, I; Crapo, JD; Pearlstein, RD; Piganelli, J; Warner, DS
MLA Citation
Sheng, H, Yang, W, Fukuda, S, Tse, HM, Paschen, W, Johnson, K, Batinic-Haberle, I, Crapo, JD, Pearlstein, RD, Piganelli, J, and Warner, DS. "Long-term neuroprotection from a potent redox-modulating metalloporphyrin in the rat." Free Radic Biol Med 47.7 (October 1, 2009): 917-923.
PMID
19631268
Source
pubmed
Published In
Free Radical Biology and Medicine
Volume
47
Issue
7
Publish Date
2009
Start Page
917
End Page
923
DOI
10.1016/j.freeradbiomed.2009.05.039

Radioprotective effects of manganese-containing superoxide dismutase mimics on ataxia-telangiectasia cells.

We tested several classes of antioxidant manganese compounds for radioprotective effects using human lymphoblastoid cells: six porphyrins, three salens, and two cyclic polyamines. Radioprotection was evaluated by seven assays: XTT, annexin V and propidium iodide flow cytometry analysis, gamma-H2AX immunofluorescence, the neutral comet assay, dichlorofluorescein and dihydroethidium staining, resazurin, and colony survival assay. Two compounds were most effective in protecting wild-type and A-T cells against radiation-induced damage: MnMx-2-PyP-Calbio (a mixture of differently N-methylated MnT-2-PyP+ from Calbiochem) and MnTnHex-2-PyP. MnTnHex-2-PyP protected WT cells against radiation-induced apoptosis by 58% (p = 0.04), using XTT, and A-T cells by 39% (p = 0.01), using annexin V and propidium iodide staining. MnTnHex-2-PyP protected WT cells against DNA damage by 57% (p = 0.005), using gamma-H2AX immunofluorescence, and by 30% (p < 0.01), using neutral comet assay. MnTnHex-2-PyP is more lipophilic than MnMx-2-PyP-Calbio and is also >10-fold more SOD-active; consequently it is >50-fold more potent as a radioprotectant, as supported by six of the tests employed in this study. Thus, lipophilicity and antioxidant potency correlated with the magnitude of the beneficial radioprotectant effects observed. Our results identify a new class of porphyrinic radioprotectants for the general and radiosensitive populations and may also provide a new option for treating A-T patients.

Authors
Pollard, JM; Reboucas, JS; Durazo, A; Kos, I; Fike, F; Panni, M; Gralla, EB; Valentine, JS; Batinic-Haberle, I; Gatti, RA
MLA Citation
Pollard, JM, Reboucas, JS, Durazo, A, Kos, I, Fike, F, Panni, M, Gralla, EB, Valentine, JS, Batinic-Haberle, I, and Gatti, RA. "Radioprotective effects of manganese-containing superoxide dismutase mimics on ataxia-telangiectasia cells." Free Radic Biol Med 47.3 (August 1, 2009): 250-260.
PMID
19389472
Source
pubmed
Published In
Free Radical Biology and Medicine
Volume
47
Issue
3
Publish Date
2009
Start Page
250
End Page
260
DOI
10.1016/j.freeradbiomed.2009.04.018

Lipophilicity of potent porphyrin-based antioxidants: comparison of ortho and meta isomers of Mn(III) N-alkylpyridylporphyrins.

Mn(III) N-alkylpyridylporphyrins are among the most potent known SOD mimics and catalytic peroxynitrite scavengers and modulators of redox-based cellular transcriptional activity. In addition to their intrinsic antioxidant capacity, bioavailability plays a major role in their in vivo efficacy. Although of identical antioxidant capacity, lipophilic MnTnHex-2-PyP is up to 120-fold more efficient in reducing oxidative stress injuries than hydrophilic MnTE-2-PyP. Owing to limitations of an analytical nature, porphyrin lipophilicity has been often estimated by the thin-layer chromatographic R(f) parameter, instead of the standard n-octanol/water partition coefficient, P(OW). Herein we used a new methodological approach to finally describe the MnP lipophilicity, using the conventional log P(OW) means, for a series of biologically active ortho and meta isomers of Mn(III) N-alkylpyridylporphyrins. Three new porphyrins (MnTnBu-3-PyP, MnTnHex-3-PyP, and MnTnHep-2-PyP) were synthesized to strengthen the conclusions. The log P(OW) was linearly related to R(f) and to the number of carbons in the alkyl chain (n(C)) for both isomer series, the meta isomers being 10-fold more lipophilic than the analogous ortho porphyrins. Increasing the length of the alkyl chain by one carbon atom increases the log P(OW) value approximately 1 log unit with both isomers. Dramatic approximately 4 and approximately 5 orders of magnitude increases in the lipophilicity of the ortho isomers, by extending the pyridyl alkyl chains from two (MnTE-2-PyP, log P(OW)=-6.89) to six (MnTnHex-2-PyP, log P(OW)=-2.76) and eight carbon atoms (MnTnOct-2-PyP, log P(OW)=-1.24), parallels the increased efficacy in several oxidative-stress injury models, particularly those of the central nervous system, in which transport across the blood-brain barrier is critical. Although meta isomers are only slightly less potent SOD mimics and antioxidants than their ortho analogues, their higher lipophilicity and smaller bulkiness may lead to a higher cellular uptake and overall similar effectiveness in vivo.

Authors
Kos, I; Rebouças, JS; DeFreitas-Silva, G; Salvemini, D; Vujaskovic, Z; Dewhirst, MW; Spasojević, I; Batinić-Haberle, I
MLA Citation
Kos, I, Rebouças, JS, DeFreitas-Silva, G, Salvemini, D, Vujaskovic, Z, Dewhirst, MW, Spasojević, I, and Batinić-Haberle, I. "Lipophilicity of potent porphyrin-based antioxidants: comparison of ortho and meta isomers of Mn(III) N-alkylpyridylporphyrins." Free Radic Biol Med 47.1 (July 1, 2009): 72-78.
PMID
19361553
Source
pubmed
Published In
Free Radical Biology and Medicine
Volume
47
Issue
1
Publish Date
2009
Start Page
72
End Page
78
DOI
10.1016/j.freeradbiomed.2009.04.002

Hyperthermia-induced HIF-1 activation and tumor reoxygenation

Authors
Moon, EJ; Li, C-Y; Batinic-Haberle, I; Dewhirst, M
MLA Citation
Moon, EJ, Li, C-Y, Batinic-Haberle, I, and Dewhirst, M. "Hyperthermia-induced HIF-1 activation and tumor reoxygenation." CANCER RESEARCH 69 (May 1, 2009).
Source
wos-lite
Published In
Cancer Research
Volume
69
Publish Date
2009

Effect of lipophilicity of Mn (III) ortho N-alkylpyridyl- and diortho N, N'-diethylimidazolylporphyrins in two in-vitro models of oxygen and glucose deprivation-induced neuronal death.

In vivo investigations have confirmed the beneficial effects of hydrophilic, cationic Mn(III) porphyrin-based catalytic antioxidants in different models of oxidative stress. Using a cell culture model of rat mixed neuronal/glial cells, this study investigated the effect of MnTnOct-2-PyP5+ on oxygen and glucose deprivation (OGD)-induced cell death as compared to the effects of widely studied hydrophilic analogues MnTE-2-PyP5+ and MnTDE-2-ImP5+ and a standard compound, dizocilpine (MK-801). It was hypothesized that the octylpyridylporphyrin, MnTnOct-2-PyP5+, a lipophilic but equally potent antioxidant as the other two porphyrins, would be more efficacious in reducing OGD-induced cell death due to its higher bioavailability. Cell death was evaluated at 24 h using lactate dehydrogenase (LDH) release and propidium iodide staining. At concentrations from 3-100 microM, all three porphyrins reduced cell death as compared to cultures exposed to OGD alone, the effects depending upon the concentrations and type of treatment. To assess the effect of lipophilicity the additional experiments were performed using submicromolar concentrations of MnTnOct-2-PyP5+ in an organotypic hippocampal slice model of OGD with propidium iodide and Sytox staining. When compared to oxygen and glucose deprivation alone, concentrations of MnTnOct-2-PyP5+ as low as 0.01 microM significantly (p<0.001; power 1.0) reduced neuronal cells similar to control. This is the first in vitro study on the mammalian cells which indicates that MnTnOct-2-PyP5+ is up to 3000-fold more efficacious than equally potent hydrophilic analogues, due entirely to its increased bioavailability. Such remarkable increase in efficacy parallels 5.7-orders of magnitude increase in lipophilicity of MnTnOct-2-PyP5+ (log P=-0.77) when compared to MnTE-2-PyP5+ (log POW=-6.43), POW being partition coefficient between n-octanol and water.

Authors
Wise-Faberowski, L; Warner, DS; Spasojevic, I; Batinic-Haberle, I
MLA Citation
Wise-Faberowski, L, Warner, DS, Spasojevic, I, and Batinic-Haberle, I. "Effect of lipophilicity of Mn (III) ortho N-alkylpyridyl- and diortho N, N'-diethylimidazolylporphyrins in two in-vitro models of oxygen and glucose deprivation-induced neuronal death." Free Radic Res 43.4 (April 2009): 329-339.
PMID
19259881
Source
pubmed
Published In
Free Radical Research (Informa)
Volume
43
Issue
4
Publish Date
2009
Start Page
329
End Page
339
DOI
10.1080/10715760902736283

IDH1 and IDH2 mutations in gliomas.

BACKGROUND: A recent genomewide mutational analysis of glioblastomas (World Health Organization [WHO] grade IV glioma) revealed somatic mutations of the isocitrate dehydrogenase 1 gene (IDH1) in a fraction of such tumors, most frequently in tumors that were known to have evolved from lower-grade gliomas (secondary glioblastomas). METHODS: We determined the sequence of the IDH1 gene and the related IDH2 gene in 445 central nervous system (CNS) tumors and 494 non-CNS tumors. The enzymatic activity of the proteins that were produced from normal and mutant IDH1 and IDH2 genes was determined in cultured glioma cells that were transfected with these genes. RESULTS: We identified mutations that affected amino acid 132 of IDH1 in more than 70% of WHO grade II and III astrocytomas and oligodendrogliomas and in glioblastomas that developed from these lower-grade lesions. Tumors without mutations in IDH1 often had mutations affecting the analogous amino acid (R172) of the IDH2 gene. Tumors with IDH1 or IDH2 mutations had distinctive genetic and clinical characteristics, and patients with such tumors had a better outcome than those with wild-type IDH genes. Each of four tested IDH1 and IDH2 mutations reduced the enzymatic activity of the encoded protein. CONCLUSIONS: Mutations of NADP(+)-dependent isocitrate dehydrogenases encoded by IDH1 and IDH2 occur in a majority of several types of malignant gliomas.

Authors
Yan, H; Parsons, DW; Jin, G; McLendon, R; Rasheed, BA; Yuan, W; Kos, I; Batinic-Haberle, I; Jones, S; Riggins, GJ; Friedman, H; Friedman, A; Reardon, D; Herndon, J; Kinzler, KW; Velculescu, VE; Vogelstein, B; Bigner, DD
MLA Citation
Yan, H, Parsons, DW, Jin, G, McLendon, R, Rasheed, BA, Yuan, W, Kos, I, Batinic-Haberle, I, Jones, S, Riggins, GJ, Friedman, H, Friedman, A, Reardon, D, Herndon, J, Kinzler, KW, Velculescu, VE, Vogelstein, B, and Bigner, DD. "IDH1 and IDH2 mutations in gliomas." N Engl J Med 360.8 (February 19, 2009): 765-773.
PMID
19228619
Source
pubmed
Published In
The New England journal of medicine
Volume
360
Issue
8
Publish Date
2009
Start Page
765
End Page
773
DOI
10.1056/NEJMoa0808710

Lipophilicity is a critical parameter that dominates the efficacy of metalloporphyrins in blocking the development of morphine antinociceptive tolerance through peroxynitrite-mediated pathways.

Severe pain syndromes reduce the quality of life of patients with inflammatory and neoplastic diseases, partly because reduced analgesic effectiveness with chronic opiate therapy (i.e., tolerance) leads to escalating doses and distressing side effects. Peroxynitrite-mediated nitroxidative stress in the dorsal horn of the spinal cord plays a critical role in the induction and development of antinociceptive tolerance to morphine. This provides a valid pharmacological basis for developing peroxynitrite scavengers as potent adjuncts to opiates in the management of pain. The cationic Mn(III) ortho-N-alkylpyridylporphyrins MnTE-2-PyP(5+) and MnTnHex-2-PyP(5+) are among the most potent peroxynitrite scavengers, with nearly identical scavenging rate constants (approximately 10(7) M(-1) s(-1)). Yet, MnTnHex-2-PyP(5+) is significantly more lipophilic and more bioavailable and, in turn, was 30-fold more effective in blocking the development of morphine antinociceptive tolerance than MnTE-2-PyP(5+) using the hot-plate test in a well-characterized murine model. The hydrophilic MnTE-2-PyP(5+) and the lipophilic MnTnHex-2-PyP(5+) were 10- and 300-fold, respectively, more effective in inhibiting morphine tolerance than the hydrophilic Fe(III) porphyrin FeTM-4-PyP(5+). Both Mn porphyrins decreased levels of TNF-alpha, IL-1 beta, and IL-6 to normal values. Neither of them affected acute morphine antinociceptive effects nor caused motor function impairment. Also neither was able to reverse already established morphine tolerance. We have recently shown that the anionic porphyrin Mn(III) tetrakis(4-carboxylatophenyl)porphyrin is selective in removing ONOO(-) over O(2)(-), but at approximately 2 orders of magnitude lower efficacy than MnTE-2-PyP(5+) and MnTnHex-2-PyP(5+), which in turn parallels up to 100-fold lower ability to reverse morphine tolerance. These data (1) support the role of peroxynitrite rather than superoxide as a major mechanism in blocking the development of morphine tolerance and (2) show that lipophilicity is a critical parameter in enhancing the potency of such novel peroxynitrite scavengers.

Authors
Batinić-Haberle, I; Ndengele, MM; Cuzzocrea, S; Rebouças, JS; Spasojević, I; Salvemini, D
MLA Citation
Batinić-Haberle, I, Ndengele, MM, Cuzzocrea, S, Rebouças, JS, Spasojević, I, and Salvemini, D. "Lipophilicity is a critical parameter that dominates the efficacy of metalloporphyrins in blocking the development of morphine antinociceptive tolerance through peroxynitrite-mediated pathways." Free Radic Biol Med 46.2 (January 15, 2009): 212-219.
PMID
18983908
Source
pubmed
Published In
Free Radical Biology and Medicine
Volume
46
Issue
2
Publish Date
2009
Start Page
212
End Page
219
DOI
10.1016/j.freeradbiomed.2008.09.037

Pure MnTBAP selectively scavenges peroxynitrite over superoxide: comparison of pure and commercial MnTBAP samples to MnTE-2-PyP in two models of oxidative stress injury, an SOD-specific Escherichia coli model and carrageenan-induced pleurisy.

MnTBAP is often referred to as an SOD mimic in numerous models of oxidative stress. We have recently reported that pure MnTBAP does not dismute superoxide, but commercial or poorly purified samples are able to perform O2.- dismutation with low-to-moderate efficacy via non-innocent Mn-containing impurities. Herein, we show that neither commercial nor pure MnTBAP could substitute for SOD enzyme in a SOD-deficient Escherichia coli model, whereas MnTE-2-PyP-treated SOD-deficient E. coli grew as well as a wild-type strain. This SOD-specific system indicates that MnTBAP does not act as an SOD mimic in vivo. In another model, carrageenan-induced pleurisy in mice, inflammation was evidenced by increased pleural fluid exudate and neutrophil infiltration and activation: these events were blocked by 0.3 mg/kg MnTE-2-PyP and, to a slightly lesser extent, by 10 mg/kg of either MnTBAP. Also, 3-nitrotyrosine formation, an indication of peroxynitrite existence in vivo, was blocked by both compounds; again MnTE-2-PyP was 33-fold more effective. Pleurisy model data indicate that MnTBAP exerts some protective actions in common with MnTE-2-PyP, which are not O2.- related and can be fully rationalized if one considers that the common biological role shared by MnTBAP and MnTE-2-PyP is related to their reduction of peroxynitrite and carbonate radical, the latter arising from ONOOCO2 adduct. The log kcat (O2.-) value for MnTBAP is estimated to be about 3.16, which is approximately 5 and approximately 6 orders of magnitude smaller than the SOD activities of the potent SOD mimic MnTE-2-PyP and Cu,Zn-SOD, respectively. This very low value indicates that MnTBAP is too inefficient at dismuting superoxide to be of any biological impact, which was confirmed in the SOD-deficient E. coli model. The peroxynitrite scavenging ability of MnTBAP, however, is only approximately 2.5 orders of magnitude smaller than that of MnTE-2-PyP and is not significantly affected by the presence of the SOD-active impurities in the commercial MnTBAP sample (log k red (ONOO-) = 5.06 for pure and 4.97 for commercial sample). The reduction of carbonate radical is equally fast with MnTBAP and MnTE-2-PyP. The dose of MnTBAP required to yield oxidative stress protection and block nitrotyrosine formation in the pleurisy model is > 1.5 orders of magnitude higher than that of MnTE-2-PyP, which could be related to the lower ability of MnTBAP to scavenge peroxynitrite. The slightly better protection observed with the commercial MnTBAP sample (relative to the pure MnTBAP) could arise from its impurities, which, by scavenging O2.-, reduce consequently the overall peroxynitrite and secondary ROS/RNS levels. These observations have profound biological repercussions as they may suggest that the effect of MnTBAP observed in numerous studies may conceivably relate to peroxynitrite scavenging. Moreover, provided that pure MnTBAP is unable to dismute superoxide at any significant extent, but is able to partially scavenge peroxynitrite and carbonate radical, this compound may prove valuable in distinguishing ONOO-/CO3.- from O2.- pathways.

Authors
Batinić-Haberle, I; Cuzzocrea, S; Rebouças, JS; Ferrer-Sueta, G; Mazzon, E; Di Paola, R; Radi, R; Spasojević, I; Benov, L; Salvemini, D
MLA Citation
Batinić-Haberle, I, Cuzzocrea, S, Rebouças, JS, Ferrer-Sueta, G, Mazzon, E, Di Paola, R, Radi, R, Spasojević, I, Benov, L, and Salvemini, D. "Pure MnTBAP selectively scavenges peroxynitrite over superoxide: comparison of pure and commercial MnTBAP samples to MnTE-2-PyP in two models of oxidative stress injury, an SOD-specific Escherichia coli model and carrageenan-induced pleurisy." Free Radic Biol Med 46.2 (January 15, 2009): 192-201.
PMID
19007878
Source
pubmed
Published In
Free Radical Biology and Medicine
Volume
46
Issue
2
Publish Date
2009
Start Page
192
End Page
201
DOI
10.1016/j.freeradbiomed.2008.09.042

Effect of potent redox-modulating manganese porphyrin, MnTM-2-PyP, on the Na(+)/H(+) exchangers NHE-1 and NHE-3 in the diabetic rat.

Increased expression of Na(+)/H(+) exchanger (NHE) and Na(+),K(+)-ATPase activity have been demonstrated in diabetic nephropathy and are implicated in the development of hypertension. The aim of this study was to investigate the effect of a synthetic manganese porphyrin SOD mimic and peroxynitrite scavenger, Mn(III) 5,10,15,20-tetrakis(N-methylpyridinium-2-yl)porphyrin (MnTM-2-PyP) on the expression of NHE and Na(+),K(+)-ATPase activity in the kidneys of streptozotocin (STZ) diabetic rats. MnTM-2-PyP administration (1 mg/kg/day) started immediately after STZ and lasted 2 months. Glucose and glycosylated hemoglobin levels were measured in blood. NHE-1 and NHE-3 isoform expression, Na(+),K(+)-ATPase activity, and markers of ROS/RNS-induced damage were determined in kidney homogenates. Diabetes caused lipid peroxidation, inactivation of aconitase, and increase of nitrotyrosine, which paralleled an increase in NHE-1 and NHE-3 expression and Na(+),K(+)-ATPase activity. MnTM-2-PyP treatment had no effect on blood glucose and glycosylated hemoglobin, but suppressed lipid peroxidation and nitrotyrosine, protected aconitase against inactivation, and reversed the induction of NHE-1 and NHE-3 isoforms. Na(+)/H(+) exchanger is under the control of redox-based cellular transcriptional activity, including members of the SP family of transcription factors. Mn(III) alkylpyridylporphyrins were previously found to inhibit activation of major transcription factors, including SP-1 via scavenging of signaling ROS/RNS. Therefore, our data suggest that, by reducing the levels of ROS/RNS, MnTM-2-PyP might interfere with signaling pathways responsible for NHE up-regulation.

Authors
Khan, I; Batinic-Haberle, I; Benov, LT
MLA Citation
Khan, I, Batinic-Haberle, I, and Benov, LT. "Effect of potent redox-modulating manganese porphyrin, MnTM-2-PyP, on the Na(+)/H(+) exchangers NHE-1 and NHE-3 in the diabetic rat." Redox Rep 14.6 (2009): 236-242.
PMID
20003708
Source
pubmed
Published In
Redox Report
Volume
14
Issue
6
Publish Date
2009
Start Page
236
End Page
242
DOI
10.1179/135100009X12525712409698

Corrigendum to "Radio-protective effects of manganese-containing superoxide dismutase mimics on ataxia telangiectasia cells" [Free Radic. Biol. Med. 47/3 (2009) 250-260] (DOI:10.1016/j.freeradbiomed.2009.04.018)

Authors
Pollard, JM; Reboucas, JS; Durazo, A; Kos, I; Fike, F; Panni, M; Gralla, EB; Valentine, JS; Batinic-Haberle, I; Gatti, RA
MLA Citation
Pollard, JM, Reboucas, JS, Durazo, A, Kos, I, Fike, F, Panni, M, Gralla, EB, Valentine, JS, Batinic-Haberle, I, and Gatti, RA. "Corrigendum to "Radio-protective effects of manganese-containing superoxide dismutase mimics on ataxia telangiectasia cells" [Free Radic. Biol. Med. 47/3 (2009) 250-260] (DOI:10.1016/j.freeradbiomed.2009.04.018)." Free Radical Biology and Medicine 47.8 (2009): 1234--.
Source
scival
Published In
Free Radical Biology & Medicine
Volume
47
Issue
8
Publish Date
2009
Start Page
1234-
DOI
10.1016/j.freeradbiomed.2009.07.004

Quality of potent Mn porphyrin-based SOD mimics and peroxynitrite scavengers for pre-clinical mechanistic/therapeutic purposes.

Cationic Mn porphyrins are among the most potent SOD mimics and peroxynitrite scavengers. They have been widely and successfully used in different models of oxidative stress and are either progressing towards or are in phase I of clinical trials. The most frequently used compounds are Mn(III) meso-tetrakis(N-ethylpyridinium-2-yl)porphyrin (MnTE-2-PyP(5+) or AEOL10113), its methyl analogue (MnTM-2-PyP(5+) or AEOL10112), and Mn(III) meso-tetrakis(4-benzoic acid)porphyrin (MnTBAP). A great discrepancy between the in vivo data obtained with Calbiochem preparations and those of authentic MnTE-2-PyP(5+) and MnTM-2-PyP(5+) samples were recently observed. Surprisingly, the commercial samples were invariably of poor identity and consisted of mixtures of nearly equal contributions of non-alkylated, mono-, di-, tri- and tetraalkylated porphyrins, lacking thus the major structural entity that determines their antioxidant potency, i.e., the four positively charged orthoN-alkylpyridyl groups that afford thermodynamic tuning of the active site and electrostatic guidance of anionic superoxide and peroxynitrite species toward the metal center. The MnTE-2-PyP(5+) and MnTM-2-PyP(5+) compounds were not even the major species in the commercial samples sold as "MnTE-2-PyP" and "MnTM-2-PyP", respectively. While we have already reported the insufficient impurity of the MnTBAP samples from Alexis and other suppliers, in one more recent lot the situation is dramatic, as 25% of the sample was not MnTBAP, but metal-free ligand, H(2)TBAP. The (unintentional) use of the Mn porphyrins of low quality compromises therapeutic and/or mechanistic conclusions. Simple techniques, which include thin-layer chromatography, electrospray-mass spectrometry, UV-vis spectroscopy, and electrochemistry described here could be used routinely to check the overall quality of Mn porphyrins in order to avoid misleading conclusions and waste of valuable resources (animals, compounds, time, manpower).

Authors
Rebouças, JS; Spasojević, I; Batinić-Haberle, I
MLA Citation
Rebouças, JS, Spasojević, I, and Batinić-Haberle, I. "Quality of potent Mn porphyrin-based SOD mimics and peroxynitrite scavengers for pre-clinical mechanistic/therapeutic purposes." J Pharm Biomed Anal 48.3 (November 4, 2008): 1046-1049.
PMID
18804338
Source
pubmed
Published In
Journal of Pharmaceutical and Biomedical Analysis
Volume
48
Issue
3
Publish Date
2008
Start Page
1046
End Page
1049
DOI
10.1016/j.jpba.2008.08.005

Pharmacokinetics of the potent redox-modulating manganese porphyrin, MnTE-2-PyP(5+), in plasma and major organs of B6C3F1 mice.

Mn(III) tetrakis(N-ethylpyridinium-2-yl)porphyrin, MnTE-2-PyP(5+), a potent catalytic superoxide and peroxynitrite scavenger, has been beneficial in several oxidative stress-related diseases thus far examined. Pharmacokinetic studies are essential for the better assessment of the therapeutic potential of MnTE-2-PyP(5+) and similar compounds, as well as for the modulation of their bioavailability and toxicity. Despite high hydrophilicity, this drug entered mitochondria after a single 10 mg/kg intraperitoneal injection at levels high enough (5.1 muM; 2.95 ng/mg protein) to protect against superoxide/peroxynitrite damage. Utilizing the same analytical approach, which involves the reduction of MnTE-2-PyP(5+) followed by the exchange of Mn(2+) with Zn(2+) and HPLC/fluorescence detection of ZnTE-2-PyP(4+), we measured levels of MnTE-2-PyP(5+) in mouse plasma, liver, kidney, lung, heart, spleen, and brain over a period of 7 days after a single intraperitoneal injection of 10 mg/kg. Two B6C3F1 female mice per time point were used. The pharmacokinetic profile in plasma and organs was complex; thus a noncompartmental approach was utilized to calculate the area under the curve, c(max), t(max), and drug elimination half-time (t(1/2)). In terms of levels of MnTE-2-PyP(5+) found, the organs can be classified into three distinct groups: (1) high levels (kidney, liver, and spleen), (2) moderate levels (lung and heart), and (3) low levels (brain). The maximal levels in plasma, kidney, spleen, lung, and heart are reached within 45 min, whereas in the case of liver a prolonged absorption phase was observed, with the maximal concentration reached at 8 h. Moreover, accumulation of the drug in brain continued beyond the time of the experiment (7 days) and is likely to be driven by the presence of negatively charged phospholipids. For tissues other than brain, a slow elimination phase (single exponential decay, t(1/2)=60 to 135 h) was observed. The calculated pharmacokinetic parameters will be used to design optimal dosing regimens in future preclinical studies utilizing this and similar compounds.

Authors
Spasojević, I; Chen, Y; Noel, TJ; Fan, P; Zhang, L; Rebouças, JS; St Clair, DK; Batinić-Haberle, I
MLA Citation
Spasojević, I, Chen, Y, Noel, TJ, Fan, P, Zhang, L, Rebouças, JS, St Clair, DK, and Batinić-Haberle, I. "Pharmacokinetics of the potent redox-modulating manganese porphyrin, MnTE-2-PyP(5+), in plasma and major organs of B6C3F1 mice." Free Radic Biol Med 45.7 (October 1, 2008): 943-949.
PMID
18598757
Source
pubmed
Published In
Free Radical Biology & Medicine
Volume
45
Issue
7
Publish Date
2008
Start Page
943
End Page
949
DOI
10.1016/j.freeradbiomed.2008.05.015

SOD-like activity of Mn(II) beta-octabromo-meso-tetrakis(N-methylpyridinium-3-yl)porphyrin equals that of the enzyme itself.

Mn porphyrins are among the most efficient SOD mimics with potency approaching that of SOD enzymes. The most potent ones, Mn(III) N-alkylpyridylporphyrins bear positive charges in a close proximity to the metal site, affording thermodynamic and kinetic facilitation for the reaction with negatively charged superoxide. The addition of electron-withdrawing bromines onto beta-pyrrolic positions dramatically improves thermodynamic facilitation for the O2*- dismutation. We have previously characterized the para isomer, Mn(II)Br(8)TM-4-PyP(4+) [Mn(II) beta-octabromo-meso-tetrakis(N-methylpyridinium-4-yl)porphyrin]. Herein we fully characterized its meta analogue, Mn(II)Br(8)TM-3-PyP(4+) with respect to UV/vis spectroscopy, electron spray mass spectrometry, electrochemistry, O2*- dismutation, metal-ligand stability, and the ability to protect SOD-deficient Escherichia coli in comparison with its para analogue. The increased electron-deficiency of the metal center stabilizes Mn in its +2 oxidation state. The metal-centered Mn(III)/Mn(II) reduction potential, E((1/2))=+468 mV vs NHE, is increased by 416 mV with respect to non-brominated analogue, Mn(III)TM-3-PyP(5+) and is only 12 mV less positive than for para isomer. Yet, the complex is significantly more stable towards the loss of metal than its para analogue. As expected, based on the structure-activity relationships, an increase in E((1/2)) results in a higher catalytic rate constant for the O2*- dismutation, log k(cat)> or =8.85; 1.5-fold increase with respect to the para isomer. The IC(50) was calculated to be < or =3.7 nM. Manipulation of the electron-deficiency of a cationic porphyrin resulted, therefore, in the highest k(cat) ever reported for a metalloporphyrin, being essentially identical to the k(cat) of superoxide dismutases (log k(cat)=8.84-9.30). The positive kinetic salt effect points to the unexpected, unique and first time recorded behavior of Mn beta-octabrominated porphyrins when compared to other Mn porphyrins studied thus far. When species of opposing charges react, the increase in ionic strength invariably results in the decreased rate constant; with brominated porphyrins the opposite was found to be true. The effect is 3.5-fold greater with meta than with para isomer, which is discussed with respect to the closer proximity of the quaternary nitrogens of the meta isomer to the metal center than that of the para isomer. The potency of Mn(II)Br(8)TM-3-PyP(4+) was corroborated by in vivo studies, where 500 nM allows SOD-deficient E. coli to grow >60% of the growth of wild type; at concentrations > or =5 microM it exhibits toxicity. Our work shows that exceptionally high k(cat) for the O2*- disproportionation can be achieved not only with an N(5)-type coordination motif, as rationalized previously for aza crown ether (cyclic polyamines) complexes, but also with a N(4)-type motif as in the Mn porphyrin case; both motifs sharing "up-down-up-down" steric arrangement.

Authors
DeFreitas-Silva, G; Rebouças, JS; Spasojević, I; Benov, L; Idemori, YM; Batinić-Haberle, I
MLA Citation
DeFreitas-Silva, G, Rebouças, JS, Spasojević, I, Benov, L, Idemori, YM, and Batinić-Haberle, I. "SOD-like activity of Mn(II) beta-octabromo-meso-tetrakis(N-methylpyridinium-3-yl)porphyrin equals that of the enzyme itself." Arch Biochem Biophys 477.1 (September 1, 2008): 105-112.
PMID
18477465
Source
pubmed
Published In
Archives of Biochemistry and Biophysics
Volume
477
Issue
1
Publish Date
2008
Start Page
105
End Page
112
DOI
10.1016/j.abb.2008.04.032

Impact of electrostatics in redox modulation of oxidative stress by Mn porphyrins: protection of SOD-deficient Escherichia coli via alternative mechanism where Mn porphyrin acts as a Mn carrier.

Understanding the factors that determine the ability of Mn porphyrins to scavenge reactive species is essential for tuning their in vivo efficacy. We present herein the revised structure-activity relationships accounting for the critical importance of electrostatics in the Mn porphyrin-based redox modulation systems and show that the design of effective SOD mimics (per se) based on anionic porphyrins is greatly hindered by inappropriate electrostatics. A new strategy for the beta-octabromination of the prototypical anionic Mn porphyrins Mn(III) meso-tetrakis(p-carboxylatophenyl)porphyrin ([Mn(III)TCPP](3-) or MnTBAP(3-)) and Mn(III) meso-tetrakis(p-sulfonatophenyl)porphyrin ([Mn(III)TSPP](3-)), to yield the corresponding anionic analogues [Mn(III)Br(8)TCPP](3-) and [Mn(III)Br(8)TSPP](3-), respectively, is described along with characterization data, stability studies, and their ability to substitute for SOD in SOD-deficient Escherichia coli. Despite the Mn(III)/Mn(II) reduction potential of [Mn(III)Br(8)TCPP](3-) and [Mn(III)Br(8)TSPP](3-) being close to the SOD-enzyme optimum and nearly identical to that of the cationic Mn(III) meso-tetrakis(N-methylpyridinium-2-yl)porphyrin (Mn(III)TM-2-PyP(5+)), the SOD activity of both anionic brominated porphyrins ([Mn(III)Br(8)TCPP](3-), E(1/2)=+213 mV vs NHE, log k(cat)=5.07; [Mn(III)Br(8)TSPP](3-), E(1/2)=+209 mV, log k(cat)=5.56) is considerably lower than that of Mn(III)TM-2-PyP(5+) (E(1/2)=+220 mV, log k(cat)=7.79). This illustrates the impact of electrostatic guidance of O(2)(-) toward the metal center of the mimic. With low k(cat), the [Mn(III)TCPP](3-), [Mn(III)TSPP](3-), and [Mn(III)Br(8)TCPP](3-) did not rescue SOD-deficient E. coli. The striking ability of [Mn(III)Br(8)TSPP](3-) to substitute for the SOD enzymes in the E. coli model does not correlate with its log k(cat). In fact, the protectiveness of [Mn(III)Br(8)TSPP](3-) is comparable to or better than that of the potent SOD mimic Mn(III)TM-2-PyP(5+), even though the dismutation rate constant of the anionic complex is 170-fold smaller. Analyses of the medium and E. coli cell extract revealed that the major species in the [Mn(III)Br(8)TSPP](3-) system is not the Mn complex, but the free-base porphyrin [H(2)Br(8)TSPP](4-) instead. Control experiments with extracellular MnCl(2) showed the lack of E. coli protection, indicating that "free" Mn(2+) cannot enter the cell to a significant extent. We proposed herein the alternative mechanism where a labile Mn porphyrin [Mn(III)Br(8)TSPP](3-) is not an SOD mimic per se but carries Mn into the E. coli cell.

Authors
Rebouças, JS; DeFreitas-Silva, G; Spasojević, I; Idemori, YM; Benov, L; Batinić-Haberle, I
MLA Citation
Rebouças, JS, DeFreitas-Silva, G, Spasojević, I, Idemori, YM, Benov, L, and Batinić-Haberle, I. "Impact of electrostatics in redox modulation of oxidative stress by Mn porphyrins: protection of SOD-deficient Escherichia coli via alternative mechanism where Mn porphyrin acts as a Mn carrier." Free Radic Biol Med 45.2 (July 15, 2008): 201-210.
PMID
18457677
Source
pubmed
Published In
Free Radical Biology & Medicine
Volume
45
Issue
2
Publish Date
2008
Start Page
201
End Page
210
DOI
10.1016/j.freeradbiomed.2008.04.009

An SOD mimic protects NADP+-dependent isocitrate dehydrogenase against oxidative inactivation.

The isocitrate dehydrogenases (ICDs) catalyse the oxidative decarboxylation of isocitrate to alpha-ketoglutarate and can use either NAD(+) or NADP(+) as a cofactor. Recent studies demonstrate that the NADP(+)-dependent isocitrate dehydrogenase, as a source of electrons for cellular antioxidants, is important for protection against oxidative damage. ICD, however, is susceptible to oxidative inactivation, which in turn compromises cellular antioxidant defense. This study investigates the effect of a superoxide dismutase (SOD) mimic, MnTM-2-PyP(5+), on the inactivation of NADP(+)-dependent ICD in SOD-deficient Escherichia coli and in diabetic rats. The findings show that E. coli ICD is inactivated by superoxide, but the inactivated enzyme is replaced by de novo protein synthesis. Statistically significant decrease of ICD activity was found in the hearts of diabetic rats. MnTM-2-PyP(5+) protected ICD in both models.

Authors
Batinic-Haberle, I; Benov, LT
MLA Citation
Batinic-Haberle, I, and Benov, LT. "An SOD mimic protects NADP+-dependent isocitrate dehydrogenase against oxidative inactivation." Free Radic Res 42.7 (July 2008): 618-624.
PMID
18608518
Source
pubmed
Published In
Free Radical Research (Informa)
Volume
42
Issue
7
Publish Date
2008
Start Page
618
End Page
624
DOI
10.1080/10715760802209639

A neuronal model of Alzheimer's disease: an insight into the mechanisms of oxidative stress-mediated mitochondrial injury.

Alzheimer's disease (AD) is associated with beta-amyloid accumulation, oxidative stress and mitochondrial dysfunction. However, the effects of genetic mutation of AD on oxidative status and mitochondrial manganese superoxide dismutase (MnSOD) production during neuronal development are unclear. To investigate the consequences of genetic mutation of AD on oxidative damages and production of MnSOD during neuronal development, we used primary neurons from new born wild-type (WT/WT) and amyloid precursor protein (APP) (NLh/NLh) and presenilin 1 (PS1) (P264L) knock-in mice (APP/PS1) which incorporated humanized mutations in the genome. Increasing levels of oxidative damages, including protein carbonyl, 4-hydroxynonenal (4-HNE) and 3-nitrotyrosine (3-NT), were accompanied by a reduction in mitochondrial membrane potential in both developing and mature APP/PS1 neurons compared with WT/WT neurons suggesting mitochondrial dysfunction under oxidative stress. Interestingly, developing APP/PS1 neurons were significantly more resistant to beta-amyloid 1-42 treatment, whereas mature APP/PS1 neurons were more vulnerable than WT/WT neurons of the same age. Consistent with the protective function of MnSOD, developing APP/PS1 neurons have increased MnSOD protein and activity, indicating an adaptive response to oxidative stress in developing neurons. In contrast, mature APP/PS1 neurons exhibited lower MnSOD levels compared with mature WT/WT neurons indicating that mature APP/PS1 neurons lost the adaptive response. Moreover, mature APP/PS1 neurons had more co-localization of MnSOD with nitrotyrosine indicating a greater inhibition of MnSOD by nitrotyrosine. Overexpression of MnSOD or addition of MnTE-2-PyP(5+) (SOD mimetic) protected against beta-amyloid-induced neuronal death and improved mitochondrial respiratory function. Together, the results demonstrate that compensatory induction of MnSOD in response to an early increase in oxidative stress protects developing neurons against beta-amyloid toxicity. However, continuing development of neurons under oxidative damage conditions may suppress the expression of MnSOD and enhance cell death in mature neurons.

Authors
Sompol, P; Ittarat, W; Tangpong, J; Chen, Y; Doubinskaia, I; Batinic-Haberle, I; Abdul, HM; Butterfield, DA; St Clair, DK
MLA Citation
Sompol, P, Ittarat, W, Tangpong, J, Chen, Y, Doubinskaia, I, Batinic-Haberle, I, Abdul, HM, Butterfield, DA, and St Clair, DK. "A neuronal model of Alzheimer's disease: an insight into the mechanisms of oxidative stress-mediated mitochondrial injury." Neuroscience 153.1 (April 22, 2008): 120-130.
PMID
18353561
Source
pubmed
Published In
Neuroscience
Volume
153
Issue
1
Publish Date
2008
Start Page
120
End Page
130
DOI
10.1016/j.neuroscience.2008.01.044

Comparison of two Mn porphyrin-based mimics of superoxide dismutase in pulmonary radioprotection.

Development of radiation therapy (RT)-induced lung injury is associated with chronic production of reactive oxygen and nitrogen species (ROS/RNS). MnTE-2-PyP5+ is a catalytic Mn porphyrin mimic of SOD, already shown to protect lungs from RT-induced injury by scavenging ROS/RNS. The purpose of this study was to compare MnTE-2-PyP5+ with a newly introduced analogue MnTnHex-2-PyP5+, which is expected to be a more effective radioprotector due to its lipophilic properties. This study shows that Fischer rats which were irradiated to their right hemithorax (28 Gy) have less pulmonary injury as measured using breathing frequencies when treated with daily subcutaneous injections of MnTE-2-PyP5+ (3 and 6 mg/kg) or MnTnHex-2-PyP5+ (0.3, 0.6, or 1.0 mg/kg) for 2 weeks after RT. However, at 16 weeks post-RT, only MnTE-2-PyP5+ at a dose of 6 mg/kg is able to ameliorate oxidative damage, block activation of HIF-1alpha and TGF-beta, and impair upregulation of CA-IX and VEGF. MnTnHex-2-PyP5+ at a dose of 0.3 mg/kg is effective only in reducing RT-induced TGF-beta and CA-IX expression. Significant loss of body weight was observed in animals receiving MnTnHex-2-PyP5+ (0.3 and 0.6 mg/kg). MnTnHex-2-PyP5+ has the ability to dissolve lipid membranes, causing local irritation/necrosis at injection sites if given at doses of 1 mg/kg or higher. In conclusion, both compounds show an ability to ameliorate lung damage as measured using breathing frequencies and histopathologic evaluation. However, MnTE-2-PyP5+ at 6 mg/kg proved to be more effective in reducing expression of key molecular factors known to play an important role in radiation-induced lung injury.

Authors
Gauter-Fleckenstein, B; Fleckenstein, K; Owzar, K; Jiang, C; Batinic-Haberle, I; Vujaskovic, Z
MLA Citation
Gauter-Fleckenstein, B, Fleckenstein, K, Owzar, K, Jiang, C, Batinic-Haberle, I, and Vujaskovic, Z. "Comparison of two Mn porphyrin-based mimics of superoxide dismutase in pulmonary radioprotection." Free Radic Biol Med 44.6 (March 15, 2008): 982-989.
PMID
18082148
Source
pubmed
Published In
Free Radical Biology & Medicine
Volume
44
Issue
6
Publish Date
2008
Start Page
982
End Page
989
DOI
10.1016/j.freeradbiomed.2007.10.058

Redox modulation of oxidative stress by Mn porphyrin-based therapeutics: the effect of charge distribution.

We evaluate herein the impact of positive charge distribution on the in vitro and in vivo properties of Mn porphyrins as redox modulators possessing the same overall 5+ charge and of minimal stericity demand: Mn(III) meso-tetrakis(trimethylanilinium-4-yl)porphyrin (MnTTriMAP(5+)), Mn(III) meso-tetrakis(N,N'-dimethylpyrazolium-4-yl)porphyrin (MnTDM-4-PzP(5+)), Mn(III) meso-tetrakis(N,N'-dimethylimidazolium-2-yl)porphyrin (MnTDM-2-ImP(5+)), and the ortho and para methylpyridinium complexes Mn(III) meso-tetrakis(N-methylpyridinium-4-yl)porphyrin (MnTM-4-PyP(5+)) and Mn(III) meso-tetrakis(N-methylpyridinium-2-yl)porphyrin (MnTM-2-PyP(5+)). Both Mn(III)/Mn(II) reduction potential and SOD activity within the series follow the order: MnTTriMAP(5+)

Authors
Rebouças, JS; Spasojević, I; Tjahjono, DH; Richaud, A; Méndez, F; Benov, L; Batinić-Haberle, I
MLA Citation
Rebouças, JS, Spasojević, I, Tjahjono, DH, Richaud, A, Méndez, F, Benov, L, and Batinić-Haberle, I. "Redox modulation of oxidative stress by Mn porphyrin-based therapeutics: the effect of charge distribution." Dalton Trans 9 (March 7, 2008): 1233-1242.
PMID
18283384
Source
pubmed
Published In
Dalton Transactions
Issue
9
Publish Date
2008
Start Page
1233
End Page
1242
DOI
10.1039/b716517j

Pure manganese(III) 5,10,15,20-tetrakis(4-benzoic acid)porphyrin (MnTBAP) is not a superoxide dismutase mimic in aqueous systems: a case of structure-activity relationship as a watchdog mechanism in experimental therapeutics and biology.

Superoxide is involved in a plethora of pathological and physiological processes via oxidative stress and/or signal transduction pathways. Superoxide dismutase (SOD) mimics have, thus, been actively sought for clinical and mechanistic purposes. Manganese(III) 5,10,15,20-tetrakis(4-benzoic acid)porphyrin (MnTBAP) is one of the most intensely explored "SOD mimics" in biology and medicine. However, we show here that this claimed SOD activity of MnTBAP in aqueous media is not corroborated by comprehensive structure-activity relationship studies for a wide set of Mn porphyrins and that MnTBAP from usual commercial sources contains different amounts of noninnocent trace impurities (Mn clusters), which inhibited xanthine oxidase and had SOD activity in their own right. In addition, the preparation and thorough characterization of a high-purity MnTBAP is presented for the first time and confirmed that pure MnTBAP has no SOD activity in aqueous medium. These findings call for an assessment of the relevance and suitability of using MnTBAP (or its impurities) as a mechanistic probe and antioxidant therapeutic; conclusions on the physiological and pathological role of superoxide derived from studies using MnTBAP of uncertain purity should be examined judiciously. An unequivocal distinction between the biological effects due to MnTBAP and that of its impurities can only be unambiguously made if a pure sample is/was used. This work also illustrates the contribution of fundamental structure-activity relationship studies not only for drug design and optimization, but also as a "watchdog" mechanism for checking/spotting eventual incongruence of drug activity in chemical and biological settings.

Authors
Rebouças, JS; Spasojević, I; Batinić-Haberle, I
MLA Citation
Rebouças, JS, Spasojević, I, and Batinić-Haberle, I. "Pure manganese(III) 5,10,15,20-tetrakis(4-benzoic acid)porphyrin (MnTBAP) is not a superoxide dismutase mimic in aqueous systems: a case of structure-activity relationship as a watchdog mechanism in experimental therapeutics and biology." J Biol Inorg Chem 13.2 (February 2008): 289-302.
PMID
18046586
Source
pubmed
Published In
JBIC Journal of Biological Inorganic Chemistry
Volume
13
Issue
2
Publish Date
2008
Start Page
289
End Page
302
DOI
10.1007/s00775-007-0324-9

Design and synthesis of manganese porphyrins with tailored lipophilicity: investigation of redox properties and superoxide dismutase activity.

Thirteen new manganese porphyrins and two porphodimethenes bearing one to three different substituents at the meso positions in a variety of architectures have been synthesized. The substituents employed generally are (i) electron-withdrawing to tune the reduction potential to the desirable range (near +0.3V vs NHE), and/or (ii) lipophilic to target the interior of lipid bilayer membranes and/or the blood-brain barrier. The influence of the substituents on the Mn(III)/Mn(II) reduction potentials has been characterized, and the superoxide dismutase activity of the compounds has been examined.

Authors
Lahaye, D; Muthukumaran, K; Hung, C-H; Gryko, D; Rebouças, JS; Spasojević, I; Batinić-Haberle, I; Lindsey, JS
MLA Citation
Lahaye, D, Muthukumaran, K, Hung, C-H, Gryko, D, Rebouças, JS, Spasojević, I, Batinić-Haberle, I, and Lindsey, JS. "Design and synthesis of manganese porphyrins with tailored lipophilicity: investigation of redox properties and superoxide dismutase activity." Bioorg Med Chem 15.22 (November 15, 2007): 7066-7086.
PMID
17822908
Source
pubmed
Published In
Bioorganic & Medicinal Chemistry
Volume
15
Issue
22
Publish Date
2007
Start Page
7066
End Page
7086
DOI
10.1016/j.bmc.2007.07.015

Low molecular weight catalytic metalloporphyrin antioxidant AEOL 10150 protects lungs from fractionated radiation.

The objective of this study was to determine whether administration of a catalytic antioxidant, Mn(III) tetrakis(N,N'-diethylimidazolium-2-yl) porphyrin, AEOL10150, reduces the severity of long-term lung injury induced by fractionated radiation (RT). Fisher 344 rats were randomized into five groups: RT+AEOL10150 (2.5 mg/kg BID), AEOL10150 (2.5 mg/kg BID) alone, RT+ AEOL10150 (5 mg/kg BID), AEOL10150 (5 mg/kg BID) alone and RT alone. Animals received five 8 Gy fractions of RT to the right hemithorax. AEOL10150 was administered 15 min before RT and 8 h later during the period of RT treatment (5 days), followed by subcutaneous injections for 30 days, twice daily. Lung histology at 26 weeks revealed a significant decrease in lung structural damage and collagen deposition in RT+AEOL10150 (5 mg/kg BID) group, in comparison to RT alone. Immunohistochemistry studies revealed a significant reduction in tissue hypoxia (HIF1alpha, CAIX), angiogenic response (VEGF, CD-31), inflammation (ED-1), oxidative stress (8-OHdG, 3-nitrotyrosine) and fibrosis pathway (TGFbeta1, Smad3, p-Smad2/3), in animals receiving RT+ AEOL10150 (5 mg/kg BID). Administration of AEOL10150 at 5 mg/kg BID during and after RT results in a significant protective effect from long-term RT-induced lung injury. Low dose (2.5 mg/kg BID) delivery of AEOL10150 has no beneficial radioprotective effects.

Authors
Rabbani, ZN; Salahuddin, FK; Yarmolenko, P; Batinic-Haberle, I; Thrasher, BA; Gauter-Fleckenstein, B; Dewhirst, MW; Anscher, MS; Vujaskovic, Z
MLA Citation
Rabbani, ZN, Salahuddin, FK, Yarmolenko, P, Batinic-Haberle, I, Thrasher, BA, Gauter-Fleckenstein, B, Dewhirst, MW, Anscher, MS, and Vujaskovic, Z. "Low molecular weight catalytic metalloporphyrin antioxidant AEOL 10150 protects lungs from fractionated radiation." Free Radic Res 41.11 (November 2007): 1273-1282.
PMID
17957541
Source
pubmed
Published In
Free Radical Research (Informa)
Volume
41
Issue
11
Publish Date
2007
Start Page
1273
End Page
1282
DOI
10.1080/10715760701689550

Inactivation of metabolic enzymes by photo-treatment with zinc meta N-methylpyridylporphyrin.

Cell proliferation is notably dependent on energy supply and generation of reducing equivalents in the form of NADPH for reductive biosynthesis. Blockage of pathways generating energy and reducing equivalents has proved successful for cancer treatment. We have previously reported that isomeric Zn(II) N-methylpyridylporphyrins (ZnTM-2(3,4)-PyP4+) can act as photosensitizers, preventing cell proliferation and causing cell death in vitro. The present study demonstrates that upon illumination, ZnTM-3-PyP inactivates glucose-6-phosphate dehydrogenase, glyceraldehyde-3-phosphate dehydrogenase, lactate dehydrogenase, NADP+ -linked isocitrate dehydrogenase, aconitase, and fumarase in adenocarcinoma LS174T cells. ZnTM-3-PyP4+ was significantly more effective than hematoporphyrin derivative (HpD) for inactivation of all enzymes, except aconitase and isocitrate dehydrogenase. Enzyme inactivation was accompanied by aggregation, presumably due to protein cross-linking of some of the enzymes tested. Inactivation of metabolic enzymes caused disruption of cancer cells' metabolism and is likely to be one of the major reasons for antiproliferative activity of ZnTM-3-PyP.

Authors
Al-Mutairi, DA; Craik, JD; Batinic-Haberle, I; Benov, LT
MLA Citation
Al-Mutairi, DA, Craik, JD, Batinic-Haberle, I, and Benov, LT. "Inactivation of metabolic enzymes by photo-treatment with zinc meta N-methylpyridylporphyrin." Biochim Biophys Acta 1770.11 (November 2007): 1520-1527.
PMID
17884296
Source
pubmed
Published In
Biochimica et Biophysica Acta: international journal of biochemistry and biophysics
Volume
1770
Issue
11
Publish Date
2007
Start Page
1520
End Page
1527
DOI
10.1016/j.bbagen.2007.06.006

Manganese porphyrin reduces renal injury and mitochondrial damage during ischemia/reperfusion.

Renal ischemia/reperfusion (I/R) injury often occurs as a result of vascular surgery, organ procurement, or transplantation. We previously showed that renal I/R results in ATP depletion, oxidant production, and manganese superoxide dismutase (MnSOD) inactivation. There have been several reports that overexpression of MnSOD protects tissues/organs from I/R-related damage, thus a loss of MnSOD activity during I/R likely contributes to tissue injury. The present study examined the therapeutic benefit of a catalytic antioxidant, Mn(III) meso-tetrakis(N-n-hexylpyridinium-2-yl)porphyrin (MnTnHex-2-PyP(5+)), using the rat renal I/R model. This was the first study to examine the effects of MnTnHex-2-PyP(5+) in an animal model of oxidative stress injury. Our results showed that porphyrin pretreatment of rats for 24 h protected against ATP depletion, MnSOD inactivation, nitrotyrosine formation, and renal dysfunction. The dose (50 microg/kg) used in this study is lower than doses of various types of antioxidants commonly used in animal models of oxidative stress injuries. In addition, using novel proteomic techniques, we identified the ATP synthase-beta subunit as a key protein induced by MnTnHex-2-PyP(5+) treatment alone and complex V (ATP synthase) as a target of injury during renal I/R. These results showed that MnTnHex-2-PyP(5+) protected against renal I/R injury via induction of key mitochondrial proteins that may be capable of blunting oxidative injury.

Authors
Saba, H; Batinic-Haberle, I; Munusamy, S; Mitchell, T; Lichti, C; Megyesi, J; MacMillan-Crow, LA
MLA Citation
Saba, H, Batinic-Haberle, I, Munusamy, S, Mitchell, T, Lichti, C, Megyesi, J, and MacMillan-Crow, LA. "Manganese porphyrin reduces renal injury and mitochondrial damage during ischemia/reperfusion." Free Radic Biol Med 42.10 (May 15, 2007): 1571-1578.
PMID
17448904
Source
pubmed
Published In
Free Radical Biology & Medicine
Volume
42
Issue
10
Publish Date
2007
Start Page
1571
End Page
1578
DOI
10.1016/j.freeradbiomed.2007.02.016

Mn porphyrin-based superoxide dismutase (SOD) mimic, MnIIITE-2-PyP5+, targets mouse heart mitochondria.

The Mn(III) meso-tetrakis(N-ethylpyridinium-2-yl)porphyrin, MnIIITE-2-PyP5+ (AEOL-10113) has proven effective in treating oxidative stress-induced conditions including cancer, radiation damage, diabetes, and central nervous system trauma. The ortho cationic pyridyl nitrogens of MnTE-2-PyP5+ are essential for its high antioxidant potency. The exceptional ability of MnIIITE-2-PyP5+ to dismute O2.- parallels its ability to reduce ONOO- and CO3-. Decreasing levels of these species are considered its predominant mode of action, which may also involve redox regulation of signaling pathways. Recently, Ferrer-Sueta at al. (Free Radic. Biol. Med. 41:503-512; 2006) showed, with submitochondrial particles, that>or=3 microM MnIIITE-2-PyP5+ was able to protect components of the mitochondrial electron transport chain from peroxynitrite-mediated damage. Our study complements their data in showing, for the first time that micromolar mitochondrial concentrations of MnIIITE-2-PyP5+ are obtainable in vivo. For this study we have developed a new and sensitive method for MnIIITE-2-PyP5+ determination in tissues. The method is based on the exchange of porphyrin Mn2+ with Zn2+, followed by the HPLC/fluorescence detection of ZnIITE-2-PyP4+. At 4 and 7 h after a single 10 mg/kg intraperitoneal administration of MnIIITE-2-PyP5+, the mice (8 in total) were anesthetized and perfused with saline. Mitochondria were then isolated by the method of Mela and Seitz (Methods Enzymol.55:39-46; 1979). We found MnIIITE-2-PyP5+ localized in heart mitochondria to 2.95 ng/mg protein. Given the average value of mitochondrial volume of 0.6 microL/mg protein, the calculated MnIIITE-2-PyP5+ concentration is 5.1 microM, which is sufficient to protect mitochondria from oxidative damage. This study establishes, for the first time, that MnIIITE-2-PyP5+, a highly charged metalloporphyrin, is capable of entering mitochondria in vivo at levels sufficient to exert there its antioxidant action; such a result encourages its development as a prospective therapeutic agent.

Authors
Spasojević, I; Chen, Y; Noel, TJ; Yu, Y; Cole, MP; Zhang, L; Zhao, Y; St Clair, DK; Batinić-Haberle, I
MLA Citation
Spasojević, I, Chen, Y, Noel, TJ, Yu, Y, Cole, MP, Zhang, L, Zhao, Y, St Clair, DK, and Batinić-Haberle, I. "Mn porphyrin-based superoxide dismutase (SOD) mimic, MnIIITE-2-PyP5+, targets mouse heart mitochondria." Free Radic Biol Med 42.8 (April 15, 2007): 1193-1200.
PMID
17382200
Source
pubmed
Published In
Free Radical Biology & Medicine
Volume
42
Issue
8
Publish Date
2007
Start Page
1193
End Page
1200
DOI
10.1016/j.freeradbiomed.2007.01.019

Long-term administration of a small molecular weight catalytic metalloporphyrin antioxidant, AEOL 10150, protects lungs from radiation-induced injury.

PURPOSE: To determine whether administration of a catalytic antioxidant, Mn(III) tetrakis(N,N'-diethylimidazolium-2-yl) porphyrin, AEOL 10150, with superoxide dismutase (SOD) mimetic properties, reduces the severity of radiation-induced injury to the lung from single-dose irradiation (RT) of 28 Gy. METHODS AND MATERIALS: Rats were randomly divided into four different dose groups (0, 1, 10, and 30 mg/kg/day of AEOL 10150), receiving either short-term (1 week) or long-term (10 weeks) drug administration via osmotic pumps. Rats received single-dose irradiation (RT) of 28 Gy to the right hemithorax. Breathing rates, body weights, blood samples, histopathology, and immunohistochemistry were used to assess lung damage. RESULTS: There was no significant difference in any of the study endpoints between the irradiated controls and the three groups receiving RT and short-term administration of AEOL 10150. For the long-term administration, functional determinants of lung damage 20 weeks postradiation were significantly worse for RT + phosphate-buffered saline (PBS) and RT + 1 mg/kg/day of AEOL 10150 as compared with the irradiated groups treated with higher doses of AEOL 10150 (10 or 30 mg/kg/day). Lung histology at 20 weeks revealed a significant decrease in structural damage and collagen deposition in rats receiving 10 or 30 mg/kg/day after radiation in comparison to the RT + PBS and 1 mg/kg/day groups. Immunohistochemistry demonstrated a significant reduction in macrophage accumulation, oxidative stress, and hypoxia in rats receiving AEOL 10150 (10 or 30 mg/kg/day) after lung irradiation compared with the RT + PBS and 1 mg/kg/day groups. CONCLUSIONS: The chronic administration of a novel catalytic antioxidant, AEOL 10150, demonstrates a significant protective effect from radiation-induced lung injury. AEOL 10150 has its primary impact on the cascade of events after irradiation, and adding the drug before irradiation and its short-term administration have no significant additional benefits.

Authors
Rabbani, ZN; Batinic-Haberle, I; Anscher, MS; Huang, J; Day, BJ; Alexander, E; Dewhirst, MW; Vujaskovic, Z
MLA Citation
Rabbani, ZN, Batinic-Haberle, I, Anscher, MS, Huang, J, Day, BJ, Alexander, E, Dewhirst, MW, and Vujaskovic, Z. "Long-term administration of a small molecular weight catalytic metalloporphyrin antioxidant, AEOL 10150, protects lungs from radiation-induced injury." Int J Radiat Oncol Biol Phys 67.2 (February 1, 2007): 573-580.
PMID
17236973
Source
pubmed
Published In
International Journal of Radiation Oncology, Biology, Physics
Volume
67
Issue
2
Publish Date
2007
Start Page
573
End Page
580
DOI
10.1016/j.ijrobp.2006.09.053

Influence of oxygen tension on interleukin 1-induced peroxynitrite formation and matrix turnover in articular cartilage.

OBJECTIVE: Osteoarthritis is characterized by the degradation of articular cartilage. The catabolic activity of chondrocytes is partly regulated by nitric oxide (NO), which with superoxide (O2-) leads to the formation of peroxynitrite (OONO-), a potentially damaging reactive species. Cartilage is avascular and functions at reduced oxygen tension. We investigated whether oxygen tension influences the effects of interleukin 1 (IL-1) on peroxynitrite formation and cartilage matrix metabolism. METHODS: Porcine cartilage explants were incubated at either 1% O2 or 20% O2 with either 1 ng/ml IL-1alpha, 25 microM MnTE-2-PyP5+ [Mn porphyrin-based catalytic antioxidant, Mn(III) tetrakis(N-ethylpyridinium-2-yl)porphyrin], or 1 ng/ml IL-1 + 25 microM MnTE-2-PyP5+ to decrease peroxynitrite formation. Nitrotyrosine, formed by nitration of tyrosine by peroxynitrite, was measured by immunoblot. Proteoglycan and collagen synthesis and proteoglycan degradation were also determined. RESULTS: IL-1-induced peroxynitrite formation was decreased in 1% O2 as compared to 20% O2. MnTE-2-PyP5+ inhibited IL-1-induced peroxynitrite formation in either 1% O2 or 20% O2. In 1% O2 (but not in 20% O2), Mn porphyrin significantly inhibited IL-1-induced proteoglycan degradation. IL-1 decreased both proteoglycan and collagen II synthesis in cartilage explants in 1% O2 or 20% O2, but MnTE-2-PyP5+ did not prevent these anti-anabolic effects. MnTE-2-PyP5+ alone caused a significant decrease in collagen synthesis at 20% O2 but not at 1% O2. CONCLUSION: Our findings show that oxygen tension alters IL-1-induced peroxynitrite formation, which can influence proteoglycan degradation. Oxygen tension may influence the effects of reactive oxygen and nitrogen species on matrix homeostasis.

Authors
Cernanec, JM; Weinberg, JB; Batinic-Haberle, I; Guilak, F; Fermor, B
MLA Citation
Cernanec, JM, Weinberg, JB, Batinic-Haberle, I, Guilak, F, and Fermor, B. "Influence of oxygen tension on interleukin 1-induced peroxynitrite formation and matrix turnover in articular cartilage." J Rheumatol 34.2 (February 2007): 401-407.
PMID
17295437
Source
pubmed
Published In
The Journal of rheumatology
Volume
34
Issue
2
Publish Date
2007
Start Page
401
End Page
407

Superoxide dismutase mimetic reduces hypoxia-induced O2*-, TGF-beta, and VEGF production by macrophages.

Normal tissue injury poses a major limitation to the success of radiation therapy (RT) in the treatment of solid tumors. We propose that radiation-induced lung injury is a result of chronic oxidative stress propagated by hypoxia-induced macrophage activation and cytokine production. Therefore, the objective of our study was two-fold. First, in vivo studies were conducted to support our hypothesis suggesting radiation injury is characterized by chronic hypoxia associated with increased macrophage infiltration/activation and pro-fibrogenic/angiogenic cytokine production. Second, we investigated the proposed mechanism of radiation injury in vitro. We demonstrate that hypoxia (0.5% O2) elicits macrophages to produce higher levels of O2*-, TGF-beta, and VEGF than normoxia. Our hypothesis that O2*- is contributing to increased macrophage cytokine production was supported by a significant reduction in TGF-beta and VEGF when redox signaling was minimized using a small molecular weight metalloporphyrin antioxidant, MnTE-2-PyP5+ .

Authors
Jackson, IL; Chen, L; Batinic-Haberle, I; Vujaskovic, Z
MLA Citation
Jackson, IL, Chen, L, Batinic-Haberle, I, and Vujaskovic, Z. "Superoxide dismutase mimetic reduces hypoxia-induced O2*-, TGF-beta, and VEGF production by macrophages." Free Radic Res 41.1 (January 2007): 8-14.
PMID
17164174
Source
pubmed
Published In
Free Radical Research (Informa)
Volume
41
Issue
1
Publish Date
2007
Start Page
8
End Page
14
DOI
10.1080/10715760600913150

Induction of oxidative cell damage by photo-treatment with zinc meta N-methylpyridylporphyrin.

We have previously reported that isomeric Zn(II) N-methylpyridylporphyrins (ZnTM-2(3,4)-PyP4 + ) can act as photosensitizers with efficacy comparable to that of hematoporphyrin derivative (HpD) in preventing cell proliferation and causing cell death in vitro. To better understand the biochemical basis of this activity, the effects of photo-activated ZnTM-3-PyP4 + on GSH/GSSG ratio, lipid peroxidation, membrane permeability, oxidative DNA damage, and the activities of SOD, catalase, glutathione reductase, and glutathione peroxidase were evaluated. Light exposure of ZnTM-3-PyP4 + -treated colon adenocarcinoma cells caused a wide spectrum of oxidative damage including depletion of GSH, inactivation of glutathione reductase and glutathione peroxidase, oxidative DNA damage and peroxidation of membrane lipids. Cell staining with Hoechst-33342 showed morphological changes consistent with both necrotic and apoptotic death sequences, depending upon the presence of oxygen.

Authors
Al-Mutairi, DA; Craik, JD; Batinic-Haberle, I; Benov, LT
MLA Citation
Al-Mutairi, DA, Craik, JD, Batinic-Haberle, I, and Benov, LT. "Induction of oxidative cell damage by photo-treatment with zinc meta N-methylpyridylporphyrin." Free Radic Res 41.1 (January 2007): 89-96.
PMID
17164182
Source
pubmed
Published In
Free Radical Research (Informa)
Volume
41
Issue
1
Publish Date
2007
Start Page
89
End Page
96
DOI
10.1080/10715760600952869

New approach to the activation of anti-cancer pro-drugs by metalloporphyrin-based cytochrome P450 mimics in all-aqueous biologically relevant system.

The low-molecular weight water-soluble Fe(III) and Mn(III) porphyrins--in biologically relevant phosphate-buffered saline medium with ascorbic acid as a source of electrons, under aerobic conditions but without co-oxidant - catalyze the hydroxylation of anti-cancer drug cyclophosphamide to active metabolite 4-hydroxycyclophosphamide in yields similar or higher than those typically obtained by the action of liver enzymes in vivo. The Fe(III) meso tetrakis(2,6-difluoro-3-sulfonatophenyl)porphyrin, highly electron-deficient at the metal site, was the most effective catalyst. If proven viable in vivo, this methodology could be expanded to localized or systemic activation of the entire family of oxazaphosphorine-based (and many other) anti-cancer drugs and become a powerful tool for an aggressive treatment of tumors with less toxic side effects to the patient.

Authors
Spasojević, I; Colvin, OM; Warshany, KR; Batinić-Haberle, I
MLA Citation
Spasojević, I, Colvin, OM, Warshany, KR, and Batinić-Haberle, I. "New approach to the activation of anti-cancer pro-drugs by metalloporphyrin-based cytochrome P450 mimics in all-aqueous biologically relevant system." J Inorg Biochem 100.11 (November 2006): 1897-1902.
PMID
16965820
Source
pubmed
Published In
Journal of Inorganic Biochemistry
Volume
100
Issue
11
Publish Date
2006
Start Page
1897
End Page
1902
DOI
10.1016/j.jinorgbio.2006.07.013

Reduction of manganese porphyrins by flavoenzymes and submitochondrial particles: a catalytic cycle for the reduction of peroxynitrite.

The reduction of manganese(III) meso-tetrakis((N-ethyl)pyridinium-2-yl)porphyrin (MnTE-2-PyP) to manganese(II) was catalyzed by flavoenzymes such as xanthine oxidase and glucose oxidase, and by Complex I and Complex II of the mitochondrial electron transport chain. The reduced manganese porphyrin has been previously shown to react rapidly with superoxide and carbonate radical anion. Herein, we describe the reaction of a reduced manganese porphyrin with peroxynitrite that proceeds as a two-electron process, has a rate constant greater than 7 x 10(6) M(-1) s(-1) (at pH 7.25 and 37 degrees C), and produces nitrite and the Mn(IV)Porphyrin. The Mn(II)/Mn(IV) redox cycle was used to divert peroxynitrite from the inactivation of succinate dehydrogenase. In a typical experiment, 5 microM MnTE-2-PyP in the presence of excess succinate was able to protect the succinate dehydrogenase and succinate oxidase activities of submitochondrial particles challenged with a cumulative dose of 140 microM peroxynitrite infused in the course of 2 h. Other MnPorphyrins that are reduced more slowly do not provide as much protection underscoring the rate limiting character of the reduction step. The data presented here serve to rationalize the pharmacological action of MnPorphyrins as peroxynitrite reduction catalysts in vivo and opens avenues for the development of MnPorphyrins to protect mitochondria from oxidative damage.

Authors
Ferrer-Sueta, G; Hannibal, L; Batinic-Haberle, I; Radi, R
MLA Citation
Ferrer-Sueta, G, Hannibal, L, Batinic-Haberle, I, and Radi, R. "Reduction of manganese porphyrins by flavoenzymes and submitochondrial particles: a catalytic cycle for the reduction of peroxynitrite." Free Radic Biol Med 41.3 (August 1, 2006): 503-512.
PMID
16843831
Source
pubmed
Published In
Free Radical Biology & Medicine
Volume
41
Issue
3
Publish Date
2006
Start Page
503
End Page
512
DOI
10.1016/j.freeradbiomed.2006.04.028

ROS production and angiogenic regulation by macrophages in response to heat therapy.

PURPOSE: It has been well established that inadequate blood supply combined with high metabolic rates of oxygen consumption results in areas of low oxygen tension (<1%) within malignant tumours and that elevating tumour temperatures above 39 degrees Celsius results in significant improvement in tumour oxygenation. Macrophages play a dual role in tumour initiation and progression having both pro-tumour and anti-tumour effects. However, the response of macrophages to heat within a hypoxic environment has not yet been clearly defined. METHODS: Raw 264.7 murine macrophages were incubated under normoxia and chronic hypoxia at temperatures ranging from 37-43 degrees Celsius. Under normoxia at 41 degrees Celsius, macrophages start to release significant levels of superoxide. The combination of heat with hypoxia constitutes an additional stimulus leading to increased respiratory burst of macrophages. RESULTS: The high levels of superoxide were found to be associated with changes in macrophage production of pro-angiogenic cytokines. While hypoxia alone (37 degrees Celsius) increased levels of hypoxia inducible factor-1alpha (HIF-1alpha) in macrophages, the combination of hypoxia and mild hyperthermia (39-41 degrees Celsius) induced a strong reduction in HIF-1alpha expression. The HIF-regulated vascular endothelial growth factor (VEGF) decreased simultaneously, revealing that heat inhibits both HIF-1alpha stabilization and transcriptional activity. CONCLUSION: The data suggest that temperatures which are readily achievable in the clinic (39-41 degrees Celsius) might be optimal for maximizing hyperthermic response. At higher temperatures, these effects are reversed, thereby limiting the therapeutic benefits of more severe hyperthermic exposure.

Authors
Jackson, IL; Batinic-Haberle, I; Sonveaux, P; Dewhirst, MW; Vujaskovic, Z
MLA Citation
Jackson, IL, Batinic-Haberle, I, Sonveaux, P, Dewhirst, MW, and Vujaskovic, Z. "ROS production and angiogenic regulation by macrophages in response to heat therapy." Int J Hyperthermia 22.4 (June 2006): 263-273.
PMID
16754348
Source
pubmed
Published In
International Journal of Hyperthermia (Informa)
Volume
22
Issue
4
Publish Date
2006
Start Page
263
End Page
273
DOI
10.1080/02656730600594027

Photosensitizing action of isomeric zinc N-methylpyridylporphyrins in human carcinoma cells.

The success of photodynamic therapy (PDT), as a minimally invasive approach, in treating both neoplastic and non-neoplastic diseases has stimulated the search for new compounds with potential application in PDT. We have previously reported that Zn(II) N-alkylpyridylporphyrins (ZnTM-2(3,4)-PyP(4+) and ZnTE-2-PyP(4+)) can act as photosensitizers and kill antibiotic-resistant bacteria. This study investigated the photosensitizing effects of the isomers of ZnTMPyP(4+) (ZnTM-2(3,4)-PyP(4+)) and respective ligands on a human colon adenocarcinoma cell line. At 10 microM and 30 min of illumination the isomeric porphyrins completely inhibited cell growth, and at 20 microM killed approximately 50% of the cancer cells. All these effects were entirely light-dependent. The isomers of the ZnTMPyP(4+) and the respective ligands show high photosensitizing efficiency and no toxicity in the dark. Their efficacy as photosensitizers is comparable to that of hematoporphyrin derivative (HpD).

Authors
Al-Mutairi, DA; Craik, JD; Batinic-Haberle, I; Benov, LT
MLA Citation
Al-Mutairi, DA, Craik, JD, Batinic-Haberle, I, and Benov, LT. "Photosensitizing action of isomeric zinc N-methylpyridylporphyrins in human carcinoma cells." Free Radic Res 40.5 (May 2006): 477-483.
PMID
16551574
Source
pubmed
Published In
Free Radical Research (Informa)
Volume
40
Issue
5
Publish Date
2006
Start Page
477
End Page
483
DOI
10.1080/10715760600577849

Effects of a manganese (III) porphyrin catalytic antioxidant in a mouse closed head injury model.

Closed head injury induces cerebral oxidative stress. The efficacy of a Mn (III) porphyrin catalytic antioxidant was assessed in a mouse closed head injury model. Mice were subjected to closed head injury and treated 15 min later with an i.v. bolus of vehicle or 3 mg/kg MnTE-2-PyP5+. Aconitase activity, Fluoro-Jade staining, glial fibrillary acidic protein immunoreactivity, and rotarod falling latencies were measured. Closed head injury altered all variables. MnTE-2-PyP5+ had no effect on any variable with the exception of attenuation of aconitase inactivation at 2 h post-closed head injury. In a second experiment, mice received 3 mg/kg or 6 mg/kg MnTE-2-PyP5+ or vehicle i.v. 15 min post-closed head injury. Rotarod and Morris water maze latencies were measured. Closed head injury altered performance in both tests. No statistically significant effect of MnTE-2-PyP5+ was observed. We conclude that single dose MnTE-2-PyP5+ does not alter outcome in this mouse closed head injury model.

Authors
Leinenweber, SB; Sheng, H; Lynch, JR; Wang, H; Batinić-Haberle, I; Laskowitz, DT; Crapo, JD; Pearlstein, RD; Warner, DS
MLA Citation
Leinenweber, SB, Sheng, H, Lynch, JR, Wang, H, Batinić-Haberle, I, Laskowitz, DT, Crapo, JD, Pearlstein, RD, and Warner, DS. "Effects of a manganese (III) porphyrin catalytic antioxidant in a mouse closed head injury model." Eur J Pharmacol 531.1-3 (February 15, 2006): 126-132.
PMID
16455070
Source
pubmed
Published In
European Journal of Pharmacology
Volume
531
Issue
1-3
Publish Date
2006
Start Page
126
End Page
132
DOI
10.1016/j.ejphar.2005.12.031

New PEG-ylated Mn(III) porphyrins approaching catalytic activity of SOD enzyme.

Two new tri(ethyleneglycol)-derivatized Mn(III) porphyrins were synthesized with the aim of increasing their bioavailability, and blood-circulating half-life. These are Mn(III) tetrakis(N-(1-(2-(2-(2-methoxyethoxy)ethoxy)ethyl)pyridinium-2-yl)porphyrin, MnTTEG-2-PyP5+ and Mn(III) tetrakis(N,N'-di(1-(2-(2-(2-methoxyethoxy)ethoxy)ethyl)imidazolium-2-yl)porphyrin, MnTDTEG-2-ImP5+. Both porphyrins have ortho pyridyl or di-ortho imidazolyl electron-withdrawing substituents at meso positions of the porphyrin ring that assure highly positive metal centered redox potentials, E1/2 = +250 mV vs. NHE for MnTTEG-2-PyP5+ and E1/2 = + 412 mV vs. NHE for MnTDTEG-2-ImP5+. As expected, from established E1/2 vs. log kcat(O2 *-) structure-activity relationships for metalloporphyrins (Batinic-Haberle et al., Inorg. Chem., 1999, 38, 4011), both compounds exhibit higher SOD-like activity than any meso-substituted Mn(III) porphyrins-based SOD mimic thus far, log kcat = 8.11 (MnTTEG-2-PyP5+) and log kcat = 8.55 (MnTDTEG-2-ImP5+), the former being only a few-fold less potent in disproportionating O2*- than the SOD enzyme itself. The new porphyrins are stable to both acid and EDTA, and non toxic to E. coli. Despite elongated substituents, which could potentially lower their ability to cross the cell wall, MnTTEG-2-PyP5+ and MnTDTEG-2-ImP5+ exhibit similar protection of SOD-deficient E. coli as their much smaller ethyl analogues MnTE-2-PyP5+ and MnTDE-2-ImP5+, respectively. Consequently, with anticipated increased blood-circulating half-life, these new Mn(III) porphyrins may be more effective in ameliorating oxidative stress injuries than ethyl analogues that have been already successfully explored in vivo.

Authors
Batinić-Haberle, I; Spasojević, I; Stevens, RD; Bondurant, B; Okado-Matsumoto, A; Fridovich, I; Vujasković, Z; Dewhirst, MW
MLA Citation
Batinić-Haberle, I, Spasojević, I, Stevens, RD, Bondurant, B, Okado-Matsumoto, A, Fridovich, I, Vujasković, Z, and Dewhirst, MW. "New PEG-ylated Mn(III) porphyrins approaching catalytic activity of SOD enzyme." Dalton Trans 4 (January 28, 2006): 617-624.
PMID
16402149
Source
pubmed
Published In
Dalton Transactions
Issue
4
Publish Date
2006
Start Page
617
End Page
624
DOI
10.1039/b513761f

The involvement of superoxide and iNOS-derived NO in cardiac dysfunction induced by pro-inflammatory cytokines.

Pro-inflammatory cytokines have been shown to depress myocardial mechanical function by enhancing peroxynitrite generation in the heart. The contribution of NO synthesized by different NOS isoforms, as well as the contribution of superoxide to this mechanism are still not clear. Isolated working hearts of iNOS(-/-) and wildtype mice were perfused for 120 min in the presence or absence of a mixture of pro-inflammatory cytokines (IL-1beta, TNF-alpha, and IFN-gamma). iNOS mRNA was detected only in cytokine-treated wildtype hearts. In wildtype hearts, cytokine treatment significantly decreased cardiac work, calculated as cardiac output times peak systolic pressure, to 31+/-9% of original values by the end of perfusion (P <0.05). The decline of cardiac work induced by cytokine treatment was significantly reduced in iNOS(-/-) hearts (63+/-5% of original value). Only cytokine-treated wildtype hearts showed decreased aconitase activity, indicating a higher level of oxidative stress in these hearts. Cytokines increased NADPH oxidase activity in both wildtype and iNOS(-/-) hearts, whereas NADH oxidase and xanthine oxidase/xanthine dehydrogenase activities were unaffected. The SOD mimetic MnTE2PyP prevented the cytokine-induced decline of cardiac work in both wildtype and iNOS(-/-) hearts. Cardiac p38 MAPK activation was unaltered in all experimental groups. Although genetic disruption of the iNOS gene provides partial protection against cytokine-induced cardiac dysfunction, iNOS-independent mechanisms, including contribution of NO from other NOS enzymes and the generation of superoxide, are also important contributors.

Authors
Csont, T; Viappiani, S; Sawicka, J; Slee, S; Altarejos, JY; Batinić-Haberle, I; Schulz, R
MLA Citation
Csont, T, Viappiani, S, Sawicka, J, Slee, S, Altarejos, JY, Batinić-Haberle, I, and Schulz, R. "The involvement of superoxide and iNOS-derived NO in cardiac dysfunction induced by pro-inflammatory cytokines." J Mol Cell Cardiol 39.5 (November 2005): 833-840.
PMID
16171809
Source
pubmed
Published In
Journal of Molecular and Cellular Cardiology
Volume
39
Issue
5
Publish Date
2005
Start Page
833
End Page
840
DOI
10.1016/j.yjmcc.2005.07.010

A manganese porphyrin superoxide dismutase mimetic enhances tumor radioresponsiveness.

PURPOSE: To determine the effect of the superoxide dismutase mimetic Mn(III) tetrakis(N-ethylpyridinium-2-yl)porphyrin (MnTE-2-PyP(5+)) on tumor radioresponsiveness. METHODS AND MATERIALS: Various rodent tumor (4T1, R3230, B16) and endothelial (SVEC) cell lines were exposed to MnTE-2-PyP(5+) and assayed for viability and radiosensitivity in vitro. Next, tumors were treated with radiation and MnTE-2-PyP(5+)in vivo, and the effects on tumor growth and vascularity were monitored. RESULTS: In vitro, MnTE-2-PyP(5+) was not significantly cytotoxic. However, at concentrations as low as 2 mumol/L it caused 100% inhibition of secretion by tumor cells of cytokines protective of irradiated endothelial cells. In vivo, combined treatment with radiation and MnTE-2-PyP(5+) achieved synergistic tumor devascularization, reducing vascular density by 78.7% within 72 h of radiotherapy (p < 0.05 vs. radiation or drug alone). Co-treatment of tumors also resulted in synergistic antitumor effects, extending tumor growth delay by 9 days (p < 0.01). CONCLUSIONS: These studies support the conclusion that MnTE-2-PyP(5+), which has been shown to protect normal tissues from radiation injury, can also improve tumor control through augmenting radiation-induced damage to the tumor vasculature.

Authors
Moeller, BJ; Batinic-Haberle, I; Spasojevic, I; Rabbani, ZN; Anscher, MS; Vujaskovic, Z; Dewhirst, MW
MLA Citation
Moeller, BJ, Batinic-Haberle, I, Spasojevic, I, Rabbani, ZN, Anscher, MS, Vujaskovic, Z, and Dewhirst, MW. "A manganese porphyrin superoxide dismutase mimetic enhances tumor radioresponsiveness." Int J Radiat Oncol Biol Phys 63.2 (October 1, 2005): 545-552.
PMID
16168847
Source
pubmed
Published In
International Journal of Radiation Oncology, Biology, Physics
Volume
63
Issue
2
Publish Date
2005
Start Page
545
End Page
552
DOI
10.1016/j.ijrobp.2005.05.026

p53 translocation to mitochondria precedes its nuclear translocation and targets mitochondrial oxidative defense protein-manganese superoxide dismutase.

The tumor suppressor gene p53 is activated by reactive oxygen species-generating agents. After activation, p53 migrates to mitochondria and nucleus, a response that eventually leads to apoptosis, but how the two events are related is unknown. Herein, we show that p53 translocation to mitochondria precedes its translocation to nucleus in JB6 skin epidermal cells treated with the tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA). Translocation of p53 to mitochondria occurs within 10 minutes after TPA application. In the mitochondria, p53 interacts with the primary antioxidant enzyme, manganese superoxide dismutase (MnSOD), consistent with the reduction of its superoxide scavenging activity, and a subsequent decrease of mitochondrial membrane potential. In contrast to the immediate action on mitochondria, p53 transcriptional activity in the nucleus increases at 1 hour following TPA application, accompanied by an increase in the levels of its target gene bax at 15 hours following TPA treatment. Activation of p53 transcriptional activity is preventable by application of a SOD mimetic (MnTE-2-PyP5+). Thus, p53 translocation to mitochondria and subsequent inactivation of MnSOD explains the observed mitochondrial dysfunction, which leads to transcription-dependent mechanisms of p53-induced apoptosis.

Authors
Zhao, Y; Chaiswing, L; Velez, JM; Batinic-Haberle, I; Colburn, NH; Oberley, TD; St Clair, DK
MLA Citation
Zhao, Y, Chaiswing, L, Velez, JM, Batinic-Haberle, I, Colburn, NH, Oberley, TD, and St Clair, DK. "p53 translocation to mitochondria precedes its nuclear translocation and targets mitochondrial oxidative defense protein-manganese superoxide dismutase." Cancer Res 65.9 (May 1, 2005): 3745-3750.
PMID
15867370
Source
pubmed
Published In
Cancer Research
Volume
65
Issue
9
Publish Date
2005
Start Page
3745
End Page
3750
DOI
10.1158/0008-5472.CAN-04-3835

A mechanism-based antioxidant approach for the reduction of skin carcinogenesis.

Studies in our laboratories showed that overexpression of manganese superoxide dismutase (MnSOD) reduced tumor incidence in a multistage skin carcinogenesis mouse model. However, reduction of MnSOD by heterozygous knockout of the MnSOD gene (MnSOD KO) did not lead to an increase in tumor incidence, because a reduction of MnSOD enhanced both cell proliferation and apoptosis. The present study extends our previous studies in the MnSOD KO mice and shows that apoptosis in mouse epidermis occurred prior to cell proliferation (6 versus 24 hours) when treated with tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA). To investigate the possibility that a timed administration of SOD following apoptosis but before proliferation may lead to suppression of tumor incidence, we applied a SOD mimetic (MnTE-2-PyP(5+)) 12 hours after each TPA treatment. Biochemical studies showed that MnTE-2-PyP(5+) suppressed the level of protein carbonyls and reduced the activity of activator protein-1 and the level of proliferating cellular nuclear antigen, without reducing the activity of p53 or DNA fragmentation following TPA treatment. Histologic examination confirmed that MnTE-2-PyP(5+) suppressed mitosis without interfering with apoptosis. Remarkably, the incidence and multiplicity of skin tumors were reduced in mice that received MnTE-2-PyP(5+) before cell proliferation. These results show a novel strategy for an antioxidant approach to cancer intervention.

Authors
Zhao, Y; Chaiswing, L; Oberley, TD; Batinic-Haberle, I; St Clair, W; Epstein, CJ; St Clair, D
MLA Citation
Zhao, Y, Chaiswing, L, Oberley, TD, Batinic-Haberle, I, St Clair, W, Epstein, CJ, and St Clair, D. "A mechanism-based antioxidant approach for the reduction of skin carcinogenesis." Cancer Res 65.4 (February 15, 2005): 1401-1405.
PMID
15735027
Source
pubmed
Published In
Cancer Research
Volume
65
Issue
4
Publish Date
2005
Start Page
1401
End Page
1405
DOI
10.1158/0008-5472.CAN-04-3334

Cryptococcus neoformans mitochondrial superoxide dismutase: an essential link between antioxidant function and high-temperature growth.

Manganese superoxide dismutase is an essential component of the mitochondrial antioxidant defense system of most eukaryotes. In the present study, we used a reverse-genetics approach to assess the contribution of the Cryptococcus neoformans manganese superoxide dismutase (Sod2) for antioxidant defense. Strains with mutations in the SOD2 gene exhibited increased susceptibility to oxidative stress as well as poor growth at elevated temperatures compared to isogenic wild-type strains. The sod2Delta mutants were also avirulent in a murine model of inhaled cryptococcosis. Reconstitution of a sod2Delta mutant restored Sod2 activity, eliminated the oxidative stress and temperature-sensitive (ts) phenotypes, and complemented the virulence phenotype. Characterization of the ts phenotype revealed a dependency between Sod2 antioxidant activity and the ability of C. neoformans cells to adapt to growth at elevated temperatures. The ts phenotype could be suppressed by the addition of either ascorbic acid (10 mM) or Mn salen (200 muM) at 30 degrees C, but not at 37 degrees C. Furthermore, sod2Delta mutant cells that were incubated for 24 h at 37 degrees C under anaerobic, but not aerobic, conditions were viable when shifted to the permissive conditions of 25 degrees C in the presence of air. These data suggest that the C. neoformans Sod2 is a major component of the antioxidant defense system in this human fungal pathogen and that adaptation to growth at elevated temperatures is also dependent on Sod2 activity.

Authors
Giles, SS; Batinic-Haberle, I; Perfect, JR; Cox, GM
MLA Citation
Giles, SS, Batinic-Haberle, I, Perfect, JR, and Cox, GM. "Cryptococcus neoformans mitochondrial superoxide dismutase: an essential link between antioxidant function and high-temperature growth." Eukaryot Cell 4.1 (January 2005): 46-54.
PMID
15643059
Source
pubmed
Published In
Eukaryotic cell
Volume
4
Issue
1
Publish Date
2005
Start Page
46
End Page
54
DOI
10.1128/EC.4.1.46-54.2005

A manganese porphyrin suppresses oxidative stress and extends the life span of streptozotocin-diabetic rats.

Enhanced oxidative stress due to hyperglycemia has been implicated in diabetic complications and is considered a major cause of cell and tissue damage. The aim of the present study was to investigate whether synthetic manganese porphyrin, Mn(III) 5,10,15,20-tetrakis(N-methylpyridinium-2-yl)porphyrin (MnTM-2-PyP5+) can ameliorate diabetes-induced oxidative stress and affect life span of diabetic rats. Diabetes was induced by a single (60 mg/kg) intraperitoneal injection of streptozotocin in male Wistar rats. Oxidative stress was monitored by measuring malondialdehyde levels (MDA) in blood plasma and erythrocytes using HPLC. The antioxidant status was assessed by measuring the total radical-trapping potential (TRAP) of blood plasma. Life span of the animals was used as an indication of the overall effect of MnTM-2-PyP5+. MnTM-2-PyP5+ was administered subcutaneously at 1 mg/kg for the duration of the experiment, five times/week followed by one week of rest. Diabetes increased plasma and erythrocyte levels of MDA and decreased TRAP. MnTM-2-PyP5+ had no effect on blood glucose and glycosylated hemoglobin, but significantly increased TRAP and lowered MDA. This Mn porphyrin decreased mortality and markedly extended the life span of the diabetic animals. MnTM-2-PyP5+ suppressed diabetes-induced oxidative stress, which presumably accounts for its beneficial effect on the life span of the diabetic rats. The results indicate that Mn(III) N-alkylpyridylporphyrins can be used as potent therapeutic agents in diabetes.

Authors
Benov, L; Batinic-Haberle, I
MLA Citation
Benov, L, and Batinic-Haberle, I. "A manganese porphyrin suppresses oxidative stress and extends the life span of streptozotocin-diabetic rats." Free Radic Res 39.1 (January 2005): 81-88.
PMID
15875815
Source
pubmed
Published In
Free Radical Research (Informa)
Volume
39
Issue
1
Publish Date
2005
Start Page
81
End Page
88

Mouse spinal cord compression injury is ameliorated by intrathecal cationic manganese(III) porphyrin catalytic antioxidant therapy.

This study evaluated the effects of the cationic manganese(III) tetrakis(N,N'-diethylimidazolium-2-yl)porphyrin catalytic antioxidant Mn(III)TDE-2-ImP5+ (AEOL 10150) on outcome from spinal cord compression (SCC) in the mouse. C57BL/6J mice were subjected to 60 min thoracic SCC after discontinuation of halothane anesthesia. In Experiment 1, mice were given intravenous Mn(III)TDE-2-ImP5+ (0.5 mg/kg bolus followed by 1 mg kg(-1) h(-1) for 24 h), methylprednisolone (30 mg/kg bolus followed by 5.4 mg kg(-1) h(-1) for 24 h), or vehicle (n = 25 per group). In Experiment 2, mice were given intrathecal Mn(III)TDE-2-ImP5+ (2.5 or 5.0 microg/kg) or vehicle (n = 18 per group). In both experiments, treatment began 5 min post-SCC onset. Rotarod performance was measured on post-SCC days 3, 7, 14, and 21. On post-SCC day 21, the spinal cord was histologically examined and a total damage score was calculated. Neither intravenous Mn(III)TDE-2-ImP5+ nor methylprednisolone altered rotarod performance (accelerated rate P = 0.11, fixed rate P = 0.11) or mean +/- S.D. total damage score (Mn(III)TDE-2-ImP5+ = 21 +/- 9, methylprednisolone = 24 +/- 8, vehicle = 22 +/- 10; P = 0.47; shams = 0). Intrathecal Mn(III)TDE-2-ImP5+ (both 2.5 and 5.0 microg) given at SCC-onset improved rotarod performance (P = 0.05) and total damage score (2.5 microg = 19 +/- 10, P = 0.04; 5.0 microg =19 +/- 8, P = 0.03) versus vehicle (26 +/- 10). These studies demonstrate sustained benefit from manganese(III) porphyrin catalytic antioxidant therapy after SCC. However, efficacy was dependent upon route of administration suggesting that bioavailability is critical in defining efficacy.

Authors
Sheng, H; Spasojevic, I; Warner, DS; Batinic-Haberle, I
MLA Citation
Sheng, H, Spasojevic, I, Warner, DS, and Batinic-Haberle, I. "Mouse spinal cord compression injury is ameliorated by intrathecal cationic manganese(III) porphyrin catalytic antioxidant therapy." Neurosci Lett 366.2 (August 12, 2004): 220-225.
PMID
15276251
Source
pubmed
Published In
Neuroscience Letters
Volume
366
Issue
2
Publish Date
2004
Start Page
220
End Page
225
DOI
10.1016/j.neulet.2004.05.050

Tetrahydrobiopterin rapidly reduces the SOD mimic Mn(III) ortho-tetrakis(N-ethylpyridinium-2-yl)porphyrin.

Mn(III) ortho-tetrakis(N-ethylpyridinium-2-yl)porphyrin (Mn(III)TE-2-PyP(5+)) effectively scavenges reactive oxygen and nitrogen species in vitro, and protects in vivo, in different rodent models of oxidative stress injuries. Further, Mn(III)TE-2-PyP(5+) was shown to be readily reduced by cellular reductants such as ascorbic acid and glutathione. We now show that tetrahydrobiopterin (BH(4)) is also able to reduce the metal center. Under anaerobic conditions, in phosphate-buffered saline (pH 7.4) at 25 +/- 0.1 degrees C, reduction of Mn(III)TE-2-PyP(5+) occurs through two reaction steps with rate constants k(1) = 1.0 x 10(4) M(-1) s(-1) and k(2) = 1.5 x 10(3) M(-1) s(-1). We ascribe these steps to the formation of tetrahydrobiopterin radical (BH(4)(.+)) (k(1)) that then undergoes oxidation to 6,7-dihydro-8H-biopterin (k(2)), which upon rearrangement gives rise to 7,8-dihydrobiopterin (7,8-BH(2)). Under aerobic conditions, Mn(III)TE-2-PyP(5+) catalytically oxidizes BH(4). This is also true for its longer chain alkyl analog, Mn(III) ortho-tetrakis(N-n-octylpyridinium-2-yl)porphyrin. The reduced Mn(II) porphyrin cannot be oxidized by 7,8-BH(2) or by l-sepiapterin. The data are discussed with regard to the possible impact of the interaction of Mn(III)TE-2-PyP(5+) with BH(4) on endothelial cell proliferation and hence on tumor antiangiogenesis via inhibition of nitric oxide synthase.

Authors
Batinić-Haberle, I; Spasojević, I; Fridovich, I
MLA Citation
Batinić-Haberle, I, Spasojević, I, and Fridovich, I. "Tetrahydrobiopterin rapidly reduces the SOD mimic Mn(III) ortho-tetrakis(N-ethylpyridinium-2-yl)porphyrin." Free Radic Biol Med 37.3 (August 1, 2004): 367-374.
PMID
15223070
Source
pubmed
Published In
Free Radical Biology & Medicine
Volume
37
Issue
3
Publish Date
2004
Start Page
367
End Page
374
DOI
10.1016/j.freeradbiomed.2004.04.041

Complementation of SOD-deficient Escherichia coli by manganese porphyrin mimics of superoxide dismutase activity.

Cationic Mn(III) porphyrins substituted on the methine bridge carbons (meso positions) with N-alkylpyridinium or N,N'-diethylimidazolium groups have been prepared and characterized, both chemically and as SOD mimics. The ortho tetrakis N-methylpyridinium compound was substantially more active than the corresponding para isomer. This ortho compound also exhibited a more positive redox potential and greater ability to facilitate the aerobic growth of a SOD-deficient Escherichia coli. Analogs with longer alkyl side chains and with methoxyethyl side chains, as well as with N,N'-diethylimidazolium and N,N'-dimethoxyethylimidazolium groups on the meso positions, have been prepared in anticipation of greater penetration of the cells due to greater lipophilicity. We now report that the more lipophilic compounds were effective at complementing the SOD-deficient E. coli at lower concentrations than were needed with the less lipophilic compounds. The greater efficacy of the more lipophilic compounds was achieved at the cost of greater toxicity that became apparent when these compounds were applied at higher concentrations.

Authors
Okado-Matsumoto, A; Batinić-Haberle, I; Fridovich, I
MLA Citation
Okado-Matsumoto, A, Batinić-Haberle, I, and Fridovich, I. "Complementation of SOD-deficient Escherichia coli by manganese porphyrin mimics of superoxide dismutase activity." Free Radic Biol Med 37.3 (August 1, 2004): 401-410.
PMID
15223074
Source
pubmed
Published In
Free Radical Biology & Medicine
Volume
37
Issue
3
Publish Date
2004
Start Page
401
End Page
410
DOI
10.1016/j.freeradbiomed.2004.04.040

Oxidants, antioxidants and the ischemic brain.

Despite numerous defenses, the brain is vulnerable to oxidative stress resulting from ischemia/reperfusion. Excitotoxic stimulation of superoxide and nitric oxide production leads to formation of highly reactive products, including peroxynitrite and hydroxyl radical, which are capable of damaging lipids, proteins and DNA. Use of transgenic mutants and selective pharmacological antioxidants has greatly increased understanding of the complex interplay between substrate deprivation and ischemic outcome. Recent evidence that reactive oxygen/nitrogen species play a critical role in initiation of apoptosis, mitochondrial permeability transition and poly(ADP-ribose) polymerase activation provides additional mechanisms for oxidative damage and new targets for post-ischemic therapeutic intervention. Because oxidative stress involves multiple post-ischemic cascades leading to cell death, effective prevention/treatment of ischemic brain injury is likely to require intervention at multiple effect sites.

Authors
Warner, DS; Sheng, H; Batinić-Haberle, I
MLA Citation
Warner, DS, Sheng, H, and Batinić-Haberle, I. "Oxidants, antioxidants and the ischemic brain." J Exp Biol 207.Pt 18 (August 2004): 3221-3231. (Review)
PMID
15299043
Source
pubmed
Published In
The Journal of experimental biology
Volume
207
Issue
Pt 18
Publish Date
2004
Start Page
3221
End Page
3231
DOI
10.1242/jeb.01022

New class of potent catalysts of O2.-dismutation. Mn(III) ortho-methoxyethylpyridyl- and di-ortho-methoxyethylimidazolylporphyrins.

Three new Mn(III) porphyrin catalysts of O2.-dismutation (superoxide dismutase mimics), bearing ether oxygen atoms within their side chains, were synthesized and characterized: Mn(III) 5,10,15,20-tetrakis[N-(2-methoxyethyl)pyridinium-2-yl]porphyrin (MnTMOE-2-PyP(5+)), Mn(III)5,10,15,20-tetrakis[N-methyl-N'-(2-methoxyethyl)imidazolium-2-yl]porphyrin (MnTM,MOE-2-ImP(5+)) and Mn(III) 5,10,15,20-tetrakis[N,N'-di(2-methoxyethyl)imidazolium-2-yl]porphyrin (MnTDMOE-2-ImP(5+)). Their catalytic rate constants for O2.-dismutation (disproportionation) and the related metal-centered redox potentials vs. NHE are: log k(cat)= 8.04 (E(1/2)=+251 mV) for MnTMOE-2-PyP(5+), log k(cat)= 7.98 (E(1/2)=+356 mV) for MnTM,MOE-2-ImP(5+) and log k(cat)= 7.59 (E(1/2)=+365 mV) for MnTDMOE-2-ImP(5+). The new porphyrins were compared to the previously described SOD mimics Mn(III) 5,10,15,20-tetrakis(N-ethylpyridinium-2-yl)porphyrin (MnTE-2-PyP(5+)), Mn(III) 5,10,15,20-tetrakis(N-n-butylpyridinium-2-yl)porphyrin (MnTnBu-2-PyP(5+)) and Mn(III) 5,10,15,20-tetrakis(N,N'-diethylimidazolium-2-yl)porphyrin (MnTDE-2-ImP(5+)). MnTMOE-2-PyP(5+) has side chains of the same length and the same E(1/2), as MnTnBu-2-PyP(5+)(k(cat)= 7.25, E(1/2)=+ 254 mV), yet it is 6-fold more potent a catalyst of O2.-dismutation , presumably due to the presence of the ether oxygen. The log k(cat)vs. E(1/2) relationship for all Mn porphyrin-based SOD mimics thus far studied is discussed. None of the new compounds were toxic to Escherichia coli in the concentration range studied (up to 30 microM), and protected SOD-deficient E. coli in a concentration-dependent manner. At 3 microM levels, the MnTDMOE-2-ImP(5+), bearing an oxygen atom within each of the eight side chains, was the most effective and offered much higher protection than MnTE-2-PyP(5+), while MnTDE-2-ImP(5+) was of very low efficacy.

Authors
Batinić-Haberle, I; Spasojević, I; Stevens, RD; Hambright, P; Neta, P; Okado-Matsumoto, A; Fridovich, I
MLA Citation
Batinić-Haberle, I, Spasojević, I, Stevens, RD, Hambright, P, Neta, P, Okado-Matsumoto, A, and Fridovich, I. "New class of potent catalysts of O2.-dismutation. Mn(III) ortho-methoxyethylpyridyl- and di-ortho-methoxyethylimidazolylporphyrins." Dalton Trans 11 (June 7, 2004): 1696-1702.
PMID
15252564
Source
pubmed
Published In
Dalton Transactions
Issue
11
Publish Date
2004
Start Page
1696
End Page
1702
DOI
10.1039/b400818a

A no-laminectomy spinal cord compression injury model in mice.

The purpose of this study was to develop a minimally invasive recovery model of spinal cord injury in the C57Bl/6J mouse. Without laminectomy, the epidural space was exposed by disruption of the T10-T11 interspinous ligament. Perpendicular to the rostral-caudal axis of the spine, a 1.5-mm silicone tube (O.D. 0.047 in.) was placed in the T11 epidural space. Prior to placement, a suture was passed through the tube allowing withdrawal of the tube after discontinuation of anesthesia. After 1, 30, 60, or 120 min (n = 5-8) of spinal cord compression (SCC), the tube was withdrawn. Neurological function was measured at 1, 3, 7, and 14 days after injury followed by histologic analysis. BBB locomotor score, rotarod latency, and screen grasping were worsened in a SCC duration-dependent manner (p < 0.0001). With increasing SCC duration, the number of histologically normal neurons in the ventral horns decreased (p < 0.0001) while the cross-sectional area of spinal cord with pancellular necrosis increased (p < 0.0001). Increased duration of SCC caused progressive rostral-caudal spread of histologic damage. The results indicate that this is a simple, reliable model with neurologic and histologic injury highly dependent on SCC duration. This model may be useful for study of spinal cord injury in genetically modified mice in the absence of anesthetic confounds while leaving the vertebral column intact.

Authors
Sheng, H; Wang, H; Homi, HM; Spasojevic, I; Batinic-Haberle, I; Pearlstein, RD; Warner, DS
MLA Citation
Sheng, H, Wang, H, Homi, HM, Spasojevic, I, Batinic-Haberle, I, Pearlstein, RD, and Warner, DS. "A no-laminectomy spinal cord compression injury model in mice." J Neurotrauma 21.5 (May 2004): 595-603.
PMID
15165367
Source
pubmed
Published In
Journal of Neurotrauma
Volume
21
Issue
5
Publish Date
2004
Start Page
595
End Page
603
DOI
10.1089/089771504774129928

Antioxidative, antinitrative, and vasculoprotective effects of a peroxisome proliferator-activated receptor-gamma agonist in hypercholesterolemia.

BACKGROUND: Peroxisome proliferator-activated receptor (PPAR) signaling pathways have been reported to exert anti-inflammatory effects and attenuate atherosclerosis formation. However, the mechanisms responsible for their anti-inflammatory and antiatherosclerotic effects remain largely unknown. The present study tested the hypothesis that a PPARgamma agonist may exert significant endothelial protection by antioxidative and antinitrative effects. METHODS AND RESULTS: Male New Zealand White rabbits were randomized to receive a normal (control) or a high-cholesterol diet and treated with vehicle or rosiglitazone (a PPARgamma agonist) 3 mg x kg(-1) x d(-1) for 5 weeks beginning 3 weeks after the high-cholesterol diet. At the end of 8 weeks of a high-cholesterol diet, the rabbits were killed, and the carotid arteries were isolated. Bioactive nitric oxide was determined functionally (endothelium-dependent vasodilatation) and biochemically (the phosphorylation of vasodilator-stimulated phosphoprotein, or P-VASP). Vascular superoxide production, PPARgamma, gp91phox, and inducible nitric oxide synthase (iNOS) expression, and vascular ONOO- formation were determined. Hypercholesterolemia caused severe endothelial dysfunction and reduced P-VASP, despite a marked increase in iNOS expression and total NOx production. Treatment with rosiglitazone enhanced PPARgamma expression, improved endothelium-dependent vasodilatation, preserved P-VASP, suppressed gp91phox and iNOS expression, reduced superoxide and total NOx production, and inhibited nitrotyrosine formation. CONCLUSIONS: The PPARgamma agonist rosiglitazone exerted a significant vascular protective effect in hypercholesterolemic rabbits, most likely by attenuation of oxidative and nitrative stresses. The endothelial protective effects of PPARgamma agonists may reduce leukocyte accumulation in vascular walls and contribute to their antiatherosclerotic effect.

Authors
Tao, L; Liu, H-R; Gao, E; Teng, Z-P; Lopez, BL; Christopher, TA; Ma, X-L; Batinic-Haberle, I; Willette, RN; Ohlstein, EH; Yue, T-L
MLA Citation
Tao, L, Liu, H-R, Gao, E, Teng, Z-P, Lopez, BL, Christopher, TA, Ma, X-L, Batinic-Haberle, I, Willette, RN, Ohlstein, EH, and Yue, T-L. "Antioxidative, antinitrative, and vasculoprotective effects of a peroxisome proliferator-activated receptor-gamma agonist in hypercholesterolemia." Circulation 108.22 (December 2, 2003): 2805-2811.
PMID
14610009
Source
pubmed
Published In
Circulation
Volume
108
Issue
22
Publish Date
2003
Start Page
2805
End Page
2811
DOI
10.1161/01.CIR.0000097003.49585.5E

Peroxynitrite flux-mediated LDL oxidation is inhibited by manganese porphyrins in the presence of uric acid.

We have studied the role of three Mn(III)porphyrins differing in charge, alkyl substituent length and reactivity, on LDL exposed to low fluxes of peroxynitrite (PN) in the presence of uric acid. Mn(III)porphyrins (5 microM, MnTE-2-PyP(5+), MnTnOct-2-PyP(5+), and MnTCPP(3-)) plus uric acid (300 microM) inhibited cholesteryl ester hydroperoxide formation, changes in REM as well as spared alpha- and gamma-tocopherol. MnTnOct-2-PyP(5+), the more lipophilic compound, was the most effective in protecting LDL lipids, while MnTCPP(3-) exerted the lesser protection. Mn(III)porphyrins react fast with PN ( approximately 10(5)-10(7) M(-1) s(-1)) to yield a O=Mn(IV) complex. The stoichiometry of uric acid consumption was approximately 1.7 moles per mol of PN, in agreement with reactions with both the O=Mn(IV) complex and nitrogen dioxide. A shift from an anti- to a pro-oxidant action of the Mn(III)porphyrin was observed after uric acid was significantly consumed, supporting competition reactions between LDL targets and uric acid for the O=Mn(IV) complex. Overall, the data is consistent with the catalytic reduction of PN in a cycle that involves a one electron oxidation of Mn(III) to Mn(IV) by PN followed by the reduction back to Mn(III) by uric acid. These antioxidant effects should predominate under in vivo conditions having plasma uric acid concentration range between 150 and 500 microM.

Authors
Trostchansky, A; Ferrer-Sueta, G; Batthyány, C; Botti, H; Batinić-Haberle, I; Radi, R; Rubbo, H
MLA Citation
Trostchansky, A, Ferrer-Sueta, G, Batthyány, C, Botti, H, Batinić-Haberle, I, Radi, R, and Rubbo, H. "Peroxynitrite flux-mediated LDL oxidation is inhibited by manganese porphyrins in the presence of uric acid." Free Radic Biol Med 35.10 (November 15, 2003): 1293-1300.
PMID
14607528
Source
pubmed
Published In
Free Radical Biology & Medicine
Volume
35
Issue
10
Publish Date
2003
Start Page
1293
End Page
1300

Reactions of manganese porphyrins with peroxynitrite and carbonate radical anion.

We have studied the reaction kinetics of ten manganese porphyrins, differing in their meso substituents, with peroxynitrite (ONOO-) and carbonate radical anion (CO3.) using stopped-flow and pulse radiolysis, respectively. Rate constants for the reactions of Mn(III) porphyrins with ONOO- ranged from 1 x 10(5) to 3.4 x 10(7) m(-1) s(-1) and correlated well with previously reported kinetic and thermodynamic data that reflect the resonance and inductive effects of the substituents on the porphyrin ring. Rate constants for the reactions of Mn(III) porphyrins with CO3. ranged from 2 x 10(8) to 1.2 x 10(9) m(-1)s(-1) at pH

Authors
Ferrer-Sueta, G; Vitturi, D; Batinic-Haberle, I; Fridovich, I; Goldstein, S; Czapski, G; Radi, R
MLA Citation
Ferrer-Sueta, G, Vitturi, D, Batinic-Haberle, I, Fridovich, I, Goldstein, S, Czapski, G, and Radi, R. "Reactions of manganese porphyrins with peroxynitrite and carbonate radical anion." J Biol Chem 278.30 (July 25, 2003): 27432-27438.
PMID
12700236
Source
pubmed
Published In
The Journal of biological chemistry
Volume
278
Issue
30
Publish Date
2003
Start Page
27432
End Page
27438
DOI
10.1074/jbc.M213302200

Electrostatic contribution in the catalysis of O2*- dismutation by superoxide dismutase mimics. MnIIITE-2-PyP5+ versus MnIIIBr8T-2-PyP+.

The Mn(III) meso-tetrakis(N-ethylpyridinium-2-yl)porphyrin (Mn(III)TE-2-PyP(5+)) is a potent superoxide dismutase (SOD) mimic in vitro and was beneficial in rodent models of oxidative stress pathologies. Its high activity has been ascribed to both the favorable redox potential of its metal center and to the electrostatic facilitation assured by the four positive charges encircling the metal center. Its comparison with the non-alkylated, singly charged analogue Mn(III) beta-octabromo meso-tetrakis(2-pyridyl)porphyrin (Mn(III)Br(8)T-2-PyP(+)) enabled us to evaluate the electrostatic contribution to the catalysis of O(2)() dismutation. Both compounds exhibit nearly identical metal-centered redox potential for Mn(III)/Mn(II) redox couple: +228 mV for Mn(III)TE-2-PyP(5+) and +219 mV versus NHE for Mn(III)Br(8)T-2-PyP(+). The eight electron-withdrawing beta pyrrolic bromines contribute equally to the redox properties of the parent Mn(III)T-2-PyP(+) as do four quaternized cationic meso ortho pyridyl nitrogens. However, the SOD-like activity of the highly charged Mn(III)TE-2-PyP(5+) is >100-fold higher (log k(cat) = 7.76) than that of the singly charged Mn(III)Br(8)T-2-PyP(+) (log k(cat) = 5.63). The kinetic salt effect showed that the catalytic rate constants of the Mn(III)TE-2-PyP(5+) and of its methyl analogue, Mn(III)TM-2-PyP(5+), are exactly 5-fold more sensitive to ionic strength than is the k(cat) of Mn(III)Br(8)T-2-PyP(+), which parallels the charge ratio of these compounds. Interestingly, only a small effect of ionic strength on the rate constant was found in the case of penta-charged para (Mn(III)TM-4-PyP(5+)) and meta isomers (Mn(III)TM-3-PyP(5+)), indicating that the placement of the positive charges in the close proximity of the metal center (ortho position) is essential for the electrostatic facilitation of O(2)() dismutation.

Authors
Spasojevic, I; Batinic-Haberle, I; Reboucas, JS; Idemori, YM; Fridovich, I
MLA Citation
Spasojevic, I, Batinic-Haberle, I, Reboucas, JS, Idemori, YM, and Fridovich, I. "Electrostatic contribution in the catalysis of O2*- dismutation by superoxide dismutase mimics. MnIIITE-2-PyP5+ versus MnIIIBr8T-2-PyP+." J Biol Chem 278.9 (February 28, 2003): 6831-6837.
PMID
12475974
Source
pubmed
Published In
The Journal of biological chemistry
Volume
278
Issue
9
Publish Date
2003
Start Page
6831
End Page
6837
DOI
10.1074/jbc.M211346200

Meso tetrakis ortho-, meta-, and para-n-alkylpyridinioporphyrins: Kinetics of copper(II) and zinc(II) incorporation and zinc porphyrin demetalation

The relative reactivities of the tetrakis(N-alkylpyridinium-X-yl)-porphyrins where X = 4 (alkyl = methyl, ethyl, n-propyl), X = 3 (methyl), and X = 2 (methyl, ethyl, n-propyl, n-butyl, n-hexyl, n-octyl) were studied in aqueous solution. From the ionic strength dependence of the metalation rate constants, the effective charge of a particular cationic porphyrin was usually larger when copper(II) rather than zinc(II) was the reactant. The kinetics of ZnOH+ incorporation and the acid catalyzed removal of zinc from the porphyrins in 1.0 M HCl were also studied. In general, the more basic 4- (para-) and 3- (meta-) isomers were the most reactive, followed by the less basic 2-(ortho-) methyl to n-butyl derivatives, with the lipophilic ortho n-hexyl and n-octyl porphyrins the least reactive. Copyright © 2003 Society of Porphyrins & Phthalocyanines.

Authors
Hambright, P; Batinić-Haberle, I; Spasojević, I
MLA Citation
Hambright, P, Batinić-Haberle, I, and Spasojević, I. "Meso tetrakis ortho-, meta-, and para-n-alkylpyridinioporphyrins: Kinetics of copper(II) and zinc(II) incorporation and zinc porphyrin demetalation." Journal of Porphyrins and Phthalocyanines 7.3 (2003): 139-146.
Source
scival
Published In
Journal of Porphyrins and Phthalocyanines
Volume
7
Issue
3
Publish Date
2003
Start Page
139
End Page
146

Hemodynamic effects of metalloporphyrin catalytic antioxidants: structure-activity relationships and species specificity.

Superoxide plays a role in blood pressure regulation in certain vascular diseases, however, its involvement in regulating basal blood pressure is uncertain. Vascular superoxide concentrations are limited by extracellular superoxide dismutase (EC-SOD), which is highly expressed in the vasculature of most animal species. Metalloporphyrins are low molecular weight, synthetic, redox-active, catalytic antioxidants that act as SOD mimetics. We evaluated the effects of metalloporphyrins on blood pressure in different animal species. The metalloporphyrin AEOL10113 (5-10 micro /kg iv), but not native or polyethylene glycol-CuZnSOD, caused a dose-dependent reduction in blood pressure in anesthetized rats. AEOL10113 had no effect on blood pressure in mice (wild-type or EC-SOD knockouts), guinea pigs, dogs, or baboons at doses up to 5 mg/kg iv Structure-activity studies indicated that metalloporphyrins with high SOD activity were more effective in lowering rat blood pressure than low-activity analogs. The blood pressure effect of AEOL10113 was not attributable to the release of manganese, nor was it affected by inhibitors of nitric oxide synthase (L-NAME) and guanylate cyclase (ODQ, 8-bromo-cGMP, and methylene blue) or nitric oxide scavengers (HbAo). Chlorpheniramine attenuated the effect, suggesting that the blood pressure response in rats is related to histamine release rather than the protection of nitric oxide.

Authors
Ross, AD; Sheng, H; Warner, DS; Piantadosi, CA; Batinic-Haberle, I; Day, BJ; Crapo, JD
MLA Citation
Ross, AD, Sheng, H, Warner, DS, Piantadosi, CA, Batinic-Haberle, I, Day, BJ, and Crapo, JD. "Hemodynamic effects of metalloporphyrin catalytic antioxidants: structure-activity relationships and species specificity." Free Radic Biol Med 33.12 (December 15, 2002): 1657-1669.
PMID
12488134
Source
pubmed
Published In
Free Radical Biology & Medicine
Volume
33
Issue
12
Publish Date
2002
Start Page
1657
End Page
1669

Catalytic Antioxidants as Novel Pharmacologic Approaches to Treatment of Ischemic Brain Injury.

Reactive oxygen species (ROS) and reactive nitrogen species (RNS) are increased following acute brain ischemia. These species have been associated with secondary injury that amplifies the magnitude of final neuronal damage. Work with both biochemical analyses and transgenic mice has shown that ROS/RNS production persists for many hours after the initial insult. This offers a potential therapeutic window for pharmacologic intervention of clinical relevance. Several classes of pharmacologic mimetics of superoxide dismutase/catalase have been synthesized. Evaluation of these catalytic antioxidants in laboratory models of acute brain injury has shown both robust neuroprotection and a prolonged therapeutic window at doses apparently devoid of neurotoxicity. (c) 2002 Prous Science. All rights reserved.

Authors
Sheng, H; Batinc-Haberle, I; Warner, DS
MLA Citation
Sheng, H, Batinc-Haberle, I, and Warner, DS. "Catalytic Antioxidants as Novel Pharmacologic Approaches to Treatment of Ischemic Brain Injury." Drug News Perspect 15.10 (December 2002): 654-665.
PMID
12677251
Source
pubmed
Published In
Drug news & perspectives
Volume
15
Issue
10
Publish Date
2002
Start Page
654
End Page
665

Effects of metalloporphyrin catalytic antioxidants in experimental brain ischemia.

Reactive oxygen species play a role in the response of brain to ischemia. The effects of metalloporphyrin catalytic antioxidants (AEOL 10113 and AEOL 10150) were examined after murine middle cerebral artery occlusion (MCAO). Ninety minutes after reperfusion from 90 min MCAO in the rat, AEOL 10113, AEOL 10150, or vehicle were given intracerebroventricularly. AEOL 10113 and AEOL 10150 similarly reduced infarct size (35%) and neurologic deficit. AEOL 10113 caused behavioral side effects at twice the neuroprotective dose while AEOL 10150 required a 15-fold increase from the neuroprotective dose to cause behavioral changes. AEOL 10150, given 6 h after 90 min MCAO, reduced total infarct size by 43% without temperature effects. Brain AEOL 10150 elimination t(1/2) was 10 h. In the mouse, intravenous AEOL 10150 infusion post-MCAO reduced both infarct size (25%) and neurologic deficit. Brain AEOL 10150 uptake, greater in the ischemic hemisphere, was dose- and time-dependent. AEOL 10150 had direct effects on proteomic events and ameliorated changes caused by ischemia. In primary mixed neuronal/glial cultures exposed to 2 h of O(2)/glucose deprivation, AEOL 10150 reduced lactate dehydrogenase release dose-dependently and selectively preserved aconitase activity in concentrations consistent with neuroprotection in vivo. AEOL 10150 is an effective neuroprotective compound offering a wide therapeutic window with a large margin of safety against adverse behavioral side effects.

Authors
Sheng, H; Enghild, JJ; Bowler, R; Patel, M; Batinić-Haberle, I; Calvi, CL; Day, BJ; Pearlstein, RD; Crapo, JD; Warner, DS
MLA Citation
Sheng, H, Enghild, JJ, Bowler, R, Patel, M, Batinić-Haberle, I, Calvi, CL, Day, BJ, Pearlstein, RD, Crapo, JD, and Warner, DS. "Effects of metalloporphyrin catalytic antioxidants in experimental brain ischemia." Free Radic Biol Med 33.7 (October 1, 2002): 947-961.
PMID
12361805
Source
pubmed
Published In
Free Radical Biology & Medicine
Volume
33
Issue
7
Publish Date
2002
Start Page
947
End Page
961

A small molecular weight catalytic metalloporphyrin antioxidant with superoxide dismutase (SOD) mimetic properties protects lungs from radiation-induced injury.

Radiation therapy (RT) is an important therapeutic modality in the treatment of thoracic tumors. The maximum doses to these tumors are often limited by the radiation tolerance of lung tissues. Lung injury from ionizing radiation is believed to be a consequence of oxidative stress and a cascade of cytokine activity. Superoxide dismutase (SOD) is a key enzyme in cellular defenses against oxidative damage. The objective of this study was to determine whether the SOD mimetic AEOL 10113 [manganese (III) mesotetrakis (N-ethylpyridinium-2-yl) porphyrin (MnTE-2-PyP(5+))] increases the tolerance of lung to ionizing radiation. AEOL 10113 was able to significantly reduce the severity of RT-induced lung injury. This was strongly supported with histopathology results and measurements of collagen deposition (hydroxyproline content). There was a significant reduction in the plasma level of the profibrogenic cytokine transforming growth factor-beta (TGF-beta) in the group of rats receiving RT + AEOL 10113. In conclusion, the novel SOD mimetic, AEOL 10113, demonstrates a significant protective effect from radiation-induced lung injury.

Authors
Vujaskovic, Z; Batinic-Haberle, I; Rabbani, ZN; Feng, Q-F; Kang, SK; Spasojevic, I; Samulski, TV; Fridovich, I; Dewhirst, MW; Anscher, MS
MLA Citation
Vujaskovic, Z, Batinic-Haberle, I, Rabbani, ZN, Feng, Q-F, Kang, SK, Spasojevic, I, Samulski, TV, Fridovich, I, Dewhirst, MW, and Anscher, MS. "A small molecular weight catalytic metalloporphyrin antioxidant with superoxide dismutase (SOD) mimetic properties protects lungs from radiation-induced injury." Free Radic Biol Med 33.6 (September 15, 2002): 857-863.
PMID
12208373
Source
pubmed
Published In
Free Radical Biology & Medicine
Volume
33
Issue
6
Publish Date
2002
Start Page
857
End Page
863

Isomeric N-alkylpyridylporphyrins and their Zn(II) complexes: inactive as SOD mimics but powerful photosensitizers.

The ortho, meta, and para isomers of cationic N-alkylpyridylporphyrins and their Zn(II) complexes were compared in terms of their photodynamic properties. The ortho Zn(II) complex was found to be the most efficient in causing photooxidation of NADH in vitro. In Escherichia coli, however, the para and meta isomers were better photosensitizers than their ortho analogs. The lower potency of the ortho compound in vivo seems to be due to its lower intracellular concentration. All porphyrins tested were more efficient in killing E. coli and in photooxidizing NADH than the hematoporphyrin derivative. Antibiotic resistance did not affect the photokill, which implies that the cationic N-alkylpyridylporphyrins, as their Zn(II) complexes, can be used as bactericidal agents against antibiotic-resistant strains of gram-negative bacteria.

Authors
Benov, L; Batinić-Haberle, I; Spasojević, I; Fridovich, I
MLA Citation
Benov, L, Batinić-Haberle, I, Spasojević, I, and Fridovich, I. "Isomeric N-alkylpyridylporphyrins and their Zn(II) complexes: inactive as SOD mimics but powerful photosensitizers." Arch Biochem Biophys 402.2 (June 15, 2002): 159-165.
PMID
12051659
Source
pubmed
Published In
Archives of Biochemistry and Biophysics
Volume
402
Issue
2
Publish Date
2002
Start Page
159
End Page
165
DOI
10.1016/S0003-9861(02)00062-0

Thermodynamics, kinetics, and mechanism of the stepwise dissociation and formation of Tris(L-lysinehydroxamato)iron(III) in aqueous acid.

pK(a) values for the hydroxamic acid, alpha-NH(3)(+), and epsilon-NH(3)(+) groups of L-lysinehydroxamic acid (LyHA, H(3)L(2+)) were found to be 6.87, 8.89, and 10.76, respectively, in aqueous solution (I = 0.1 M, NaClO(4)) at 25 degrees C. O,O coordination to Fe(III) by LyHA is supported by H(+) stoichiometry, UV-vis spectral shifts, and a shift in nu(CO) from 1648 to 1592 cm(-1) upon formation of mono(L-lysinehydroxamato)tetra(aquo)iron(III) (Fe(H(2)L)(H(2)O)(4)(4+)). The stepwise formation of tris(L-lysinehydroxamato)iron(III) from Fe(H(2)O)(6)(3+) and H(3)L(2+) was characterized by spectrophotometric titration, and the values for log beta(1), log beta(2), and log beta(3) are 6.80(9), 12.4(2), and 16.1(2), respectively, at 25 degrees C and I = 2.0 M (NaClO(4)). Stopped-flow spectrophotometry was used to study the proton-driven stepwise ligand dissociation kinetics of tris(L-lysinehydroxamato)iron(III) at 25 degrees C and I = 2.0 M (HClO(4)/NaClO(4)). Defining k(n) and k(-n) as the stepwise ligand dissociation and association rate constants and n as the number of bound LyHA ligands, k(3), k(-3), k(2), k(-2), k(1), and k(-1) are 3.0 x 10(4), 2.4 x 10(1), 3.9 x 10(2), 1.9 x 10(1), 1.4 x 10(-1), and 1.2 x 10(-1) M(-1) s(-1), respectively. These rate and equilibrium constants are compared with corresponding constants for Fe(III) complexes of acetohydroxamic acid (AHA) and N-methylacetohydroxamic acid (NMAHA) in the form of a linear free energy relationship. The role of electrostatics in these complexation reactions to form the highly charged Fe(LyHA)(3)(6+) species is discussed, and an interchange mechanism mediated by charge repulsion is presented. The reduction potential for tris(L-lysinehydroxamato)iron(III) is -214 mV (vs. NHE), and a comparison to other hydroxamic acid complexes of Fe(III) is made through a correlation between E(1/2) and pFe.

Authors
Wirgau, JI; Spasojević, I; Boukhalfa, H; Batinić-Haberle, I; Crumbliss, AL
MLA Citation
Wirgau, JI, Spasojević, I, Boukhalfa, H, Batinić-Haberle, I, and Crumbliss, AL. "Thermodynamics, kinetics, and mechanism of the stepwise dissociation and formation of Tris(L-lysinehydroxamato)iron(III) in aqueous acid." Inorg Chem 41.6 (March 25, 2002): 1464-1473.
PMID
11896715
Source
pubmed
Published In
Inorganic Chemistry
Volume
41
Issue
6
Publish Date
2002
Start Page
1464
End Page
1473

A metalloporphyrin-based superoxide dismutase mimic inhibits adoptive transfer of autoimmune diabetes by a diabetogenic T-cell clone.

We present here the first report of a metalloporphyrin-based antioxidant that can prevent or delay the onset of autoimmune diabetes. Type 1 diabetes is an autoimmune process whereby T-cells recognize pancreatic beta-cell antigens and initiate a leukocyte infiltrate that produces proinflammatory cytokines and reactive oxygen species (ROS), ultimately leading to beta-cell destruction. Because islet beta-cells have a reduced capacity to scavenge free radicals, they are very sensitive to ROS action. Metalloporphyrin-based superoxide dismutase (SOD) mimics scavenge ROS and protect cells from oxidative stress and apoptosis. To investigate the effect of SOD mimics and the role of oxidative stress in the development of autoimmune diabetes in vivo, we used a diabetogenic T-cell clone, BDC-2.5, to induce rapid onset of diabetes in young nonobese diabetic-severe combined immunodeficient mice (NOD.scid). Disease was significantly delayed or prevented altogether by treatment of recipient mice with an SOD mimic, AEOL-10113, before transfer of the BDC-2.5 clone. To investigate the mechanisms of protection, in vitro assays for T-cell proliferation and gamma-interferon (IFN-gamma) production were carried out using the T-cell clone BDC-2.5. We found that the SOD mimic significantly inhibited antigen-presenting cell-dependent T-cell proliferation and IFN-gamma production in vitro. In addition, pretreatment of lipopolysaccharide (LPS)-stimulated peritoneal macrophages with SOD mimic inhibited the LPS-dependent increase in TNF-alpha as well as the NADPH oxidase-dependent release of superoxide. Finally, this compound protected NIT-1 insulinoma cells from interleukin-1beta and alloxan cytotoxicity in vitro.

Authors
Piganelli, JD; Flores, SC; Cruz, C; Koepp, J; Batinic-Haberle, I; Crapo, J; Day, B; Kachadourian, R; Young, R; Bradley, B; Haskins, K
MLA Citation
Piganelli, JD, Flores, SC, Cruz, C, Koepp, J, Batinic-Haberle, I, Crapo, J, Day, B, Kachadourian, R, Young, R, Bradley, B, and Haskins, K. "A metalloporphyrin-based superoxide dismutase mimic inhibits adoptive transfer of autoimmune diabetes by a diabetogenic T-cell clone." Diabetes 51.2 (February 2002): 347-355.
PMID
11812741
Source
pubmed
Published In
Diabetes
Volume
51
Issue
2
Publish Date
2002
Start Page
347
End Page
355

Erratum: Manganese(III) complexes with porphyrins and related compounds as catalytic scavengers of superoxide (Inorganica Chimica Acta (2001) 317 (230-242))

Authors
Spasojevi, I; Batini-Haberle, I
MLA Citation
Spasojevi, I, and Batini-Haberle, I. "Erratum: Manganese(III) complexes with porphyrins and related compounds as catalytic scavengers of superoxide (Inorganica Chimica Acta (2001) 317 (230-242))." Inorganica Chimica Acta 328.1 (2002): 263--.
Source
scival
Published In
Inorganica Chimica Acta
Volume
328
Issue
1
Publish Date
2002
Start Page
263-
DOI
10.1016/S0020-1693(01)00701-0

Manganese porphyrins and related compounds as mimics of superoxide dismutase.

Authors
Batinić-Haberle, I
MLA Citation
Batinić-Haberle, I. "Manganese porphyrins and related compounds as mimics of superoxide dismutase." Methods Enzymol 349 (2002): 223-233.
PMID
11912911
Source
pubmed
Published In
Methods in Enzymology
Volume
349
Publish Date
2002
Start Page
223
End Page
233

Manganese(III) meso-tetrakis(ortho-N-alkylpyridyl)porphyrins. Synthesis, characterization, and catalysis of O2/·- dismutation

A series of ortho isomers of meso-tetrakis(N-alkylpyridyl)porphyrins (alkyl being methyl, ethyl, n-propyl, n-butyl, n-hexyl, and n-octyl) and their Mn(III) complexes were synthesized and characterized by elemental analysis, uv/vis spectroscopy, electrospray ionization mass spectrometry and electrochemistry. An increase in the number of carbon atoms in the alkyl chains from 1 to 8 is accompanied by an increase in: (a) lipophilicity, as measured by the chromatographic retention factor, Rf; (b) metal-centered redox potential, E1/2 from +220 to +367 mV vs. NHE, and (c) proton dissociation constant, pKa2 from 10.9 to 13.2. A linear correlation was found between E1/2 and Rf of the Mn(III) porphyrins and between the pKa2 and Rf of the metal-free compounds. As the porphyrins become increasingly more lipophilic, the decrease in hydration disfavors the creation of charge, while enhancing the electron-withdrawing effect of the positively charged pyridyl nitrogen atoms. Consequently, E1/2 increases linearly with the increase in pKa2, a trend in porphyrin basicity opposite from the one we previously reported for other water-soluble Mn(III) porphyrins. All of these Mn(III) porphyrins are potent catalysts for superoxide dismutation (disproportionation). Despite the favorable increase of E1/2 with the increase in chain length, the catalytic rate constant decreases from methyl (log kcat = 7.79) to n-butyl, and then increases such that the n-octyl is as potent a SOD mimic as are the methyl and ethyl compounds. The observed behavior originates from an interplay of hydration and steric effects that modulate electronic effects.

Authors
Batinić-Haberle, I; Spasojević, I; Stevens, RD; Hambright, P; Fridovich, I
MLA Citation
Batinić-Haberle, I, Spasojević, I, Stevens, RD, Hambright, P, and Fridovich, I. "Manganese(III) meso-tetrakis(ortho-N-alkylpyridyl)porphyrins. Synthesis, characterization, and catalysis of O2/·- dismutation." Journal of the Chemical Society, Dalton Transactions 13 (2002): 2689-2696.
Source
scival
Published In
Dalton : an international journal of inorganic chemistry.
Issue
13
Publish Date
2002
Start Page
2689
End Page
2696

Oxygen radical inhibition of nitric oxide-dependent vascular function in sickle cell disease.

Plasma xanthine oxidase (XO) activity was defined as a source of enhanced vascular superoxide (O(2)( *-)) and hydrogen peroxide (H(2)O(2)) production in both sickle cell disease (SCD) patients and knockout-transgenic SCD mice. There was a significant increase in the plasma XO activity of SCD patients that was similarly reflected in the SCD mouse model. Western blot and enzymatic analysis of liver tissue from SCD mice revealed decreased XO content. Hematoxylin and eosin staining of liver tissue of knockout-transgenic SCD mice indicated extensive hepatocellular injury that was accompanied by increased plasma content of the liver enzyme alanine aminotransferase. Immunocytochemical and enzymatic analysis of XO in thoracic aorta and liver tissue of SCD mice showed increased vessel wall and decreased liver XO, with XO concentrated on and in vascular luminal cells. Steady-state rates of vascular O(2)( *-) production, as indicated by coelenterazine chemiluminescence, were significantly increased, and nitric oxide (( *)NO)-dependent vasorelaxation of aortic ring segments was severely impaired in SCD mice, implying oxidative inactivation of ( *)NO. Pretreatment of aortic vessels with the superoxide dismutase mimetic manganese 5,10,15,20-tetrakis(N-ethylpyridinium-2-yl)porphyrin markedly decreased O(2)( small middle dot-) levels and significantly restored acetylcholine-dependent relaxation, whereas catalase had no effect. These data reveal that episodes of intrahepatic hypoxia-reoxygenation associated with SCD can induce the release of XO into the circulation from the liver. This circulating XO can then bind avidly to vessel luminal cells and impair vascular function by creating an oxidative milieu and catalytically consuming (*)NO via O(2)( small middle dot-)-dependent mechanisms.

Authors
Aslan, M; Ryan, TM; Adler, B; Townes, TM; Parks, DA; Thompson, JA; Tousson, A; Gladwin, MT; Patel, RP; Tarpey, MM; Batinic-Haberle, I; White, CR; Freeman, BA
MLA Citation
Aslan, M, Ryan, TM, Adler, B, Townes, TM, Parks, DA, Thompson, JA, Tousson, A, Gladwin, MT, Patel, RP, Tarpey, MM, Batinic-Haberle, I, White, CR, and Freeman, BA. "Oxygen radical inhibition of nitric oxide-dependent vascular function in sickle cell disease." Proc Natl Acad Sci U S A 98.26 (December 18, 2001): 15215-15220.
PMID
11752464
Source
pubmed
Published In
Proceedings of the National Academy of Sciences of USA
Volume
98
Issue
26
Publish Date
2001
Start Page
15215
End Page
15220
DOI
10.1073/pnas.221292098

Neuroprotection from delayed postischemic administration of a metalloporphyrin catalytic antioxidant.

Reactive oxygen species contribute to ischemic brain injury. This study examined whether the porphyrin catalytic antioxidant manganese (III) meso-tetrakis (N-ethylpyridinium-2-yl)porphyrin (MnTE-2-PyP(5+)) reduces oxidative stress and improves outcome from experimental cerebral ischemia. Rats that were subjected to 90 min focal ischemia and 7 d recovery were given MnTE-2-PyP(5+) (or vehicle) intracerebroventricularly 60 min before ischemia, or 5 or 90 min or 6 or 12 hr after reperfusion. Biomarkers of brain oxidative stress were measured at 4 hr after postischemic treatment (5 min or 6 hr). MnTE-2-PyP(5+), given 60 min before ischemia, improved neurologic scores and reduced total infarct size by 70%. MnTE-2-PyP(5+), given 5 or 90 min after reperfusion, reduced infarct size by 70-77% and had no effect on temperature. MnTE-2-PyP(5+) treatment 6 hr after ischemia reduced total infarct volume by 54% (vehicle, 131 +/- 60 mm(3); MnTE-2-PyP(5+), 300 ng, 60 +/- 68 mm(3)). Protection was observed in both cortex and caudoputamen, and neurologic scores were improved. No MnTE-2-PyP(5+) effect was observed if it was given 12 hr after ischemia. MnTE-2-PyP(5+) prevented mitochondrial aconitase inactivation and reduced 8-hydroxy-2'-deoxyguanosine formation when it was given 5 min or 6 hr after ischemia. In mice, MnTE-2-PyP(5+) reduced infarct size and improved neurologic scores when it was given intravenously 5 min after ischemia. There was no effect of 150 or 300 ng of MnTE-2-PyP(5+) pretreatment on selective neuronal necrosis resulting from 10 min forebrain ischemia and 5 d recovery in rats. Administration of a metalloporphyrin catalytic antioxidant had marked neuroprotective effects against focal ischemic insults when it was given up to 6 hr after ischemia. This was associated with decreased postischemic superoxide-mediated oxidative stress.

Authors
Mackensen, GB; Patel, M; Sheng, H; Calvi, CL; Batinic-Haberle, I; Day, BJ; Liang, LP; Fridovich, I; Crapo, JD; Pearlstein, RD; Warner, DS
MLA Citation
Mackensen, GB, Patel, M, Sheng, H, Calvi, CL, Batinic-Haberle, I, Day, BJ, Liang, LP, Fridovich, I, Crapo, JD, Pearlstein, RD, and Warner, DS. "Neuroprotection from delayed postischemic administration of a metalloporphyrin catalytic antioxidant." J Neurosci 21.13 (July 1, 2001): 4582-4592.
PMID
11425886
Source
pubmed
Published In
The Journal of neuroscience : the official journal of the Society for Neuroscience
Volume
21
Issue
13
Publish Date
2001
Start Page
4582
End Page
4592

Manganese(III) biliverdin IX dimethyl ester: a powerful catalytic scavenger of superoxide employing the Mn(III)/Mn(IV) redox couple.

A manganese(III) complex of biliverdin IX dimethyl ester, (MnIIIBVDME)2, was prepared and characterized by elemental analysis, UV/vis spectroscopy, cyclic voltammetry, chronocoulometry, electrospray mass spectrometry, freezing-point depression, magnetic susceptibility, and catalytic dismuting of superoxide anion (O2.-). In a dimeric conformation each trivalent manganese is bound to four pyrrolic nitrogens of one biliverdin dimethyl ester molecule and to the enolic oxygen of another molecule. This type of coordination stabilizes the +4 metal oxidation state, whereby the +3/+4 redox cycling of the manganese in aqueous medium was found to be at E1/2 = +0.45 V vs NHE. This potential allows the Mn(III)/Mn(IV) couple to efficiently catalyze the dismutation of O2.- with the catalytic rate constant of kcat = 5.0 x 10(7) M-1 s-1 (concentration calculated per manganese) obtained by cytochrome c assay at pH 7.8 and 25 degrees C. The fifth coordination site of the manganese is occupied by an enolic oxygen, which precludes binding of NO., thus enhancing the specificity of the metal center toward O2.-. For the same reason the (MnIIIBVDME)2 is resistant to attack by H2O2. The compound also proved to be an efficient SOD mimic in vivo, facilitating the aerobic growth of SOD-deficient Escherichia coli.

Authors
Spasojević, I; Batinić-Haberle, I; Stevens, RD; Hambright, P; Thorpe, AN; Grodkowski, J; Neta, P; Fridovich, I
MLA Citation
Spasojević, I, Batinić-Haberle, I, Stevens, RD, Hambright, P, Thorpe, AN, Grodkowski, J, Neta, P, and Fridovich, I. "Manganese(III) biliverdin IX dimethyl ester: a powerful catalytic scavenger of superoxide employing the Mn(III)/Mn(IV) redox couple." Inorg Chem 40.4 (February 12, 2001): 726-739.
PMID
11225116
Source
pubmed
Published In
Inorganic Chemistry
Volume
40
Issue
4
Publish Date
2001
Start Page
726
End Page
739

Manganese(III) complexes with porphyrins and related compounds as catalytic scavengers of superoxide

Two groups of Mn-based catalytic antioxidants are described in terms of their catalytic activities and electrochemical properties. In the first group, manganese porphyrins, phthalocyanine, and porphyrazine employ the Mn(III)/Mn(II) couple in the catalysis of O 2·- dismutation (disproportionation). The catalytic rate constant is dependent upon the metal-centered redox potential, as shown previously for water-soluble Mn porphyrins. The limitation of this simple relation becomes obvious with compounds of high redox potential (+ 2 metal oxidation state is stabilized) which exhibit a weak metal/ligand binding; although of high superoxide dismutase (SOD)-like activity, the compounds are not stable under physiological conditions. The second generation of the potent O 2·- scavengers are manganese complexes with biliverdin IX and its derivatives which have an RO - functionality as a fifth coordination to the metal center in a dimeric structure. Such a coordination pattern stabilizes the + 4 oxidation state of the manganese so that the Mn(III)/Mn(IV) redox (E 1/2 = ∼ + 0.46 V vs. NHE) becomes coupled to the O 2·- dismutation. More importantly, despite operating at a high positive metal-centered redox potential and having the + 3 oxidation state as the resting state of the metal center, metallobiliverdins still retain a high ligand affinity in solution. Independently of their charge (two neutral and the other two negatively charged) metallobiliverdins studied are of similar SOD-like activity comparable to the efficacy of highly charged manganese(III) ortho N-alkylpyridylporphyrins. These most potent in vitro SOD-like Mn porphyrins are also reactive towards peroxynitrite, nitric oxide, hydrogen peroxide and oxygen. Since the fifth coordination site of the metal center is occupied no reactivity of the manganese(III) biliverdin IX dimethyl ester towards NO · and H 2O 2 is observed. Thus, manganese(III) porphyrins and manganese(III) biliverdins are expected to differ with regards to their tissue localization and to the type and the concentration of reactive oxygen species they would encounter in biological systems. Comparative kinetic and thermodynamic studies of these catalytic antioxidants would help us understand not only the prevalent mode of their in vivo biological action but the mechanism of oxidative stress injuries as well. © 2001 Elsevier Science B.V.

Authors
Spasojevi, I; Batini-Haberle, I
MLA Citation
Spasojevi, I, and Batini-Haberle, I. "Manganese(III) complexes with porphyrins and related compounds as catalytic scavengers of superoxide." Inorganica Chimica Acta 317.1-2 (2001): 230-242.
Source
scival
Published In
Inorganica Chimica Acta
Volume
317
Issue
1-2
Publish Date
2001
Start Page
230
End Page
242
DOI
10.1016/S0020-1693(01)00365-6

Nitrosylation of manganese(II) tetrakis(N-ethylpyridinium-2-yl)porphyrin: a simple and sensitive spectrophotometric assay for nitric oxide.

Reaction between NO(*) and manganese tetrakis(N-ethylpyridinium-2-yl)porphyrin (Mn(III)TE-2-PyP(5+)) was investigated at 25 degrees C. At high excess of NO(*) (1.5 mM) the reaction with the oxidized, air-stable form Mn(III)TE-2-PyP(5+) (5 microM), proceeds very slowly (t(1/2) congruent with 60 min). The presence of excess ascorbate (1 mM) produces the reduced form, Mn(II)TE-2-PyP(4+), which reacts with NO(*) stoichiometrically and in the time of mixing (k congruent with 1 x 10(6) M(-1) s(-1)). The high rate of formation and the stability of the product, Mn(II)TE-2-PyP(NO)(4+) (¿Mn(NO)¿(6)), make the reaction outcompete the reaction of NO(*) with O(2). Our in vitro measurements show a linear absorbance response upon addition of NO to a PBS, pH 7.4, solution containing an excess of ascorbate over Mn(III)TE-2-PyP(5+). Thus, the observed interactions can be the basis of a convenient and sensitive spectrophotometric assay for NO(*). Also, it may have important implications for the in vivo behavior of Mn(III)TE-2-PyP(5+) which is currently exploited as a possible therapeutic agent for various oxygen-radical related disorders.

Authors
Spasojevic, I; Batinic-Haberle, I; Fridovich, I
MLA Citation
Spasojevic, I, Batinic-Haberle, I, and Fridovich, I. "Nitrosylation of manganese(II) tetrakis(N-ethylpyridinium-2-yl)porphyrin: a simple and sensitive spectrophotometric assay for nitric oxide." Nitric Oxide 4.5 (October 2000): 526-533.
PMID
11020341
Source
pubmed
Published In
Nitric Oxide: Biology and Chemistry
Volume
4
Issue
5
Publish Date
2000
Start Page
526
End Page
533
DOI
10.1006/niox.2000.0303

Manganese-porphyrin reactions with lipids and lipoproteins.

Manganese porphyrin complexes serve to catalytically scavenge superoxide, hydrogen peroxide, and peroxynitrite. Herein, reactions of manganese 5,10,15,20-tetrakis(N-ethylpyridinium-2-yl)porphyrin (MnTE-2-PyP(5+)) with lipids and lipid hydroperoxides (LOOH) are examined. In linoleic acid and human low-density lipoprotein (LDL), MnTE-2-PyP(5+) promotes oxidative reactions when biological reductants are not present. By redox cycling between Mn(+3) and Mn(+4) forms, MnTE-2-PyP(5+) initiates lipid peroxidation via decomposition of 13(S)hydroperoxyoctadecadienoic acid [13(S)HPODE], with a second-order rate constant of 8.9 x 10(3) M(-1)s(-1)and k(cat) = 0.32 s(-1). Studies of LDL oxidation demonstrate that: (i) MnTE-2-PyP(5+) can directly oxidize LDL, (ii) MnTE-2-PyP(5+) does not inhibit Cu-induced LDL oxidation, and (iii) MnTE-2-PyP(5+) plus a reductant partially inhibit lipid peroxidation. MnTE-2-PyP(5+) (1-5 microM) also significantly inhibits FeCl(3) plus ascorbate-induced lipid peroxidation of rat brain homogenate. In summary, MnTE-2-PyP(5+) initiates membrane lipid and lipoprotein oxidation in the absence of biological reductants, while MnTE-2-PyP(5+) inhibits lipid oxidation reactions initiated by other oxidants when reductants are present. It is proposed that, as the Mn(+3) resting redox state of MnTE-2-PyP(5+) becomes oxidized to the Mn(+4) redox state, LOOH is decomposed to byproducts that propagate lipid oxidation reactions. When the manganese of MnTE-2-PyP(5+) is reduced to the +2 state by biological reductants, antioxidant reactions of the metalloporphyrin are favored.

Authors
Bloodsworth, A; O'Donnell, VB; Batinic-Haberle, I; Chumley, PH; Hurt, JB; Day, BJ; Crow, JP; Freeman, BA
MLA Citation
Bloodsworth, A, O'Donnell, VB, Batinic-Haberle, I, Chumley, PH, Hurt, JB, Day, BJ, Crow, JP, and Freeman, BA. "Manganese-porphyrin reactions with lipids and lipoproteins." Free Radic Biol Med 28.7 (April 1, 2000): 1017-1029.
PMID
10832063
Source
pubmed
Published In
Free Radical Biology & Medicine
Volume
28
Issue
7
Publish Date
2000
Start Page
1017
End Page
1029

Electrospray mass spectrometry of isomeric tetrakis(N-alkylpyridyl)porphyrins and their manganese(III) and iron(III) complexes

Manganese(III) complexes of isomeric tetrakis(N-alkylpyridyl)porphyrins (N-alkyl = N-methyl, M or N-ethyl, E), MnTM(E)-2(3,4)-PyP5+, are being developed as superoxide dismutase (SOD) mimics. Simultaneously, techniques for their purification, identification and characterization are being pursued. Electrospray mass spectrometry (ESMS) proved to be an excellent method for identification and characterization of this group of water-soluble cationic porphyrins. The multiply charged parent ion is observed for both the metal-free ligands and their corresponding manganese complexes. The other major peaks in the mass spectra result from loss of N-alkyl groups, reduction of the metal center, axial coordination of chloride or hydroxo ion in the case of the Fe porphyrin, loss of metal and deprotonation of pyrrolic nitrogens. As a result of inductive and resonance effects, which stabilize the ortho isomer, almost no loss of N-alkyl groups from the manganese complex or from its parent ligand was observed. The relative intensity of the multiply charged molecular ion Mn(III)TM-3(4)-PyP5+/5 was 100% in the case of the meta and para isomers. Although manganese porphyrins display a low preference toward axial ligation, favorable electrostatics at the metal center of the ortho isomer gives rise to 100% relative intensity of the species that has chloride axially ligated at the manganese site, Mn(III)TM(E)-2-PyPCI4+/4. When the stronger preference of iron porphyrins toward axial ligation combines with the ortho effect, the monohydroxo iron porphyrin Fe(III)TM-2-PyP(OH)4+/4 dominates the ESMS of an aqueous acetonitrile solution at pH 7.8. Copyright (C) 2000 John Wiley and Sons, Ltd.

Authors
Batinic-Haberle, I; Stevens, RD; Fridovich, I
MLA Citation
Batinic-Haberle, I, Stevens, RD, and Fridovich, I. "Electrospray mass spectrometry of isomeric tetrakis(N-alkylpyridyl)porphyrins and their manganese(III) and iron(III) complexes." Journal of Porphyrins and Phthalocyanines 4.3 (2000): 217-227.
Source
scival
Published In
Journal of Porphyrins and Phthalocyanines
Volume
4
Issue
3
Publish Date
2000
Start Page
217
End Page
227
DOI
10.1002/(SICI)1099-1409(200004/05)4:3<217::AID-JPP198>3.0.CO;2-E

An anionic impurity in preparations of cytochrome c interferes with assays of cationic catalysts of the dismutation of the superoxide anion radical.

Authors
Batinic-Haberle, I; Benov, L; Fridovich, I
MLA Citation
Batinic-Haberle, I, Benov, L, and Fridovich, I. "An anionic impurity in preparations of cytochrome c interferes with assays of cationic catalysts of the dismutation of the superoxide anion radical." Anal Biochem 275.2 (November 15, 1999): 267-.
PMID
10552917
Source
pubmed
Published In
Analytical Biochemistry
Volume
275
Issue
2
Publish Date
1999
Start Page
267
DOI
10.1006/abio.1999.4318

Catalytic scavenging of peroxynitrite by isomeric Mn(III) N-methylpyridylporphyrins in the presence of reductants.

Three isomers of manganese(III) 5,10,15, 20-tetrakis(N-methylpyridyl)porphyrin (MnTMPyP) were evaluated for their reaction with peroxynitrite. The Mn(III) complexes reacted with peroxynitrite anion with rate constants of 1.85 x 10(7), 3.82 x 10(6), and 4.33 x 10(6) M(-1) s(-1) at 37 degrees C for MnTM-2-PyP, MnTM-3-PyP, and MnTM-4-PyP, respectively, to yield the corresponding oxo-Mn(IV) complexes. Throughout the pH range from 5 to 8.5, MnTM-2-PyP reacted 5-fold faster than the other two isomers. The oxo-Mn(IV) complexes could in turn be reduced by glutathione, ascorbate, urate, or oxidize tyrosine. The rate constants for the reduction of the oxo-Mn(IV) complexes ranged from >10(7) M(-1) s(-1) for ascorbate to 10(3)-10(4) M(-1) s(-1) for tyrosine and glutathione. Cyclic voltammetry experiments show that there is no significant difference in the E1/2 of the Mn(IV)/Mn(III) couple; thus, the differential reactivity of the three isomeric complexes is interpreted in terms of electrostatic and steric effects. Micromolar concentrations of MnTM-2-PyP compete well with millimolar CO2 at reacting with ONOO-, and it can even scavenge a fraction of the ONOOCO2- that is formed. By being rapidly oxidized by ONOO- and ONOOCO2- and reduced by antioxidants such as ascorbate, urate, and glutathione, these manganese porphyrins, and especially MnTM-2-PyP, can redirect the oxidative potential of peroxynitrite toward natural antioxidants, thus protecting more critical targets such as proteins and nucleic acids.

Authors
Ferrer-Sueta, G; Batinić-Haberle, I; Spasojević, I; Fridovich, I; Radi, R
MLA Citation
Ferrer-Sueta, G, Batinić-Haberle, I, Spasojević, I, Fridovich, I, and Radi, R. "Catalytic scavenging of peroxynitrite by isomeric Mn(III) N-methylpyridylporphyrins in the presence of reductants." Chem Res Toxicol 12.5 (May 1999): 442-449.
PMID
10328755
Source
pubmed
Published In
Chemical Research in Toxicology
Volume
12
Issue
5
Publish Date
1999
Start Page
442
End Page
449
DOI
10.1021/tx980245d

Metalloporphyrins are potent inhibitors of lipid peroxidation.

The objectives of these studies were to determine whether metalloporphyrins could inhibit lipid peroxidation, characterize factors that influence their potency and compare their potency to prototypical antioxidants. Lipid peroxidation was initiated with iron and ascorbate in rat brain homogenates and the formation of thiobarbituric acid reactive species was used as an index of lipid peroxidation. Metalloporphyrins were found to be a novel and potent class of lipid peroxidation inhibitors. Inhibition of lipid peroxidation by metalloporphyrins was dependent on the transition metal ligated to the porphyrin, indicating that metal centered redox chemistry was important to the mechanism of their antioxidant activities. Manganese porphyrins with the highest superoxide dismutase (SOD) activities, MnOBTM-4-PyP and MnTM-2-PyP (charges are omitted throughout text for clarity), were the most potent inhibitors of lipid peroxidation with calculated IC50s of 1.3 and 1.0 microM, respectively. These manganese porphyrins were 2 orders of magnitude more potent than either trolox (IC50 = 204 microM) or rutin (IC50 = 112 microM). The potencies of the manganese porphyrins were related not only to their redox potentials and SOD activities, but also to other factors that may contribute to their ability to act as electron acceptors. The broad array of antioxidant activities possessed by metalloporphyrins make them attractive therapeutic agents in disease states that involve the overproduction of reactive oxygen species.

Authors
Day, BJ; Batinic-Haberle, I; Crapo, JD
MLA Citation
Day, BJ, Batinic-Haberle, I, and Crapo, JD. "Metalloporphyrins are potent inhibitors of lipid peroxidation." Free Radic Biol Med 26.5-6 (March 1999): 730-736.
PMID
10218663
Source
pubmed
Published In
Free Radical Biology & Medicine
Volume
26
Issue
5-6
Publish Date
1999
Start Page
730
End Page
736

Relationship among redox potentials, proton dissociation constants of pyrrolic nitrogens, and in vivo and in vitro superoxide dismutating activities of manganese(III) and iron(III) water-soluble porphyrins

The log k cat values for the dismutation of O 2- by a series of monohydroxoiron(III) and aquamanganese(III) porphyrins, including ortho, meta, and para isomers of 5,10,15,20-tetrakis(N-alkylpyridiniumyl)porphyrins, were found to vary linearly with the metal-centered redox potentials (E 1/2) for the M(III)/M(II) couple. Each 120 mV increase in E 1/2 imparted a 10-fold increase in k cat. The observed behavior is in accord with the Marcus equation for outer-sphere electron-transfer reactions, suggesting that the same mechanism is operative for iron and manganese porphyrins. The Marcus plot enabled us to estimate the self-exchange rate constants of monohydroxoiron porphyrins to be ∼1 order of magnitude higher than those of aquamanganese porphyrins. Furthermore, E 1/2 values for all of the metalloporhyrins investigated were linearly related to the acid dissociation constants (pK a3) of the pyrrolic nitrogen of the metal-free porphyrins, indicating that either E 1/2, or the more readily measured pK a3, may be useful in predicting SOD activity in vitro. The most potent compounds investigated, with respect to SOD activity, are those of the ortho N-alkylpyridiniumyl series. Ortho N-alkylpyridiniumyl groups are more electron withdrawing than are the meta or para groups, thus imparting a more positive redox potential and a correspondingly higher SOD activity. Sufficiently positive potentials, or sufficiently low pK a3 values, are necessary for useful SOD activity, but so is the absence of toxicity. Despite their favorable redox potentials and SOD activities, all Fe(III) porphyrins investigated were toxic to Escherichia coli under both aerobic and anaerobic conditions and to both SOD-deficient and SOD-proficient strains. Only the ortho and meta manganese isomers of the N-alkylpyridiniumyl series (Mn III-TE-2-PyP 5+, Mn IIITM-2-PyP 5+ and Mn IIITM-3-PyP 5+) significantly protected SOD-deficient E. coli and allowed growth in an aerobic minimal medium. In previous work, we established that the lower toxicity of these compounds is due to diminished ability to bind to nucleic acids. The Mn(III) complexes are preferable to the Fe(III) complexes for SOD mimics possibly due to a lower tendency for axial ligation. We propose E 1/2 ≥ +0.05 V vs NHE and/or pK a3 ≤ 2.0 as necessary requirements for Mn porphyrins to be considered useful SOD mimics. © 1999 American Chemical Society.

Authors
Batinić-Haberle, I; Spasojević, I; Hambright, P; Benov, L; Cmmbliss, AL; Fridovich, I
MLA Citation
Batinić-Haberle, I, Spasojević, I, Hambright, P, Benov, L, Cmmbliss, AL, and Fridovich, I. "Relationship among redox potentials, proton dissociation constants of pyrrolic nitrogens, and in vivo and in vitro superoxide dismutating activities of manganese(III) and iron(III) water-soluble porphyrins." Inorganic Chemistry 38.18 (1999): 4011-4022.
Source
scival
Published In
Inorganic Chemistry
Volume
38
Issue
18
Publish Date
1999
Start Page
4011
End Page
4022

Syntheses and superoxide dismuting activities of partially (1-4) β-chlorinated derivatives of manganese(III) meso-tetrakis(N-ethylpyridinium-2-yl)porphyrin

Manganese(III) β-mono-, di-, tri-, and tetrachloro-5,10,15,20-tetrakis(N-ethylpyridinium-2-yl)porphyrin (MnClx-TE-2-PyP5+, with x from 1 to 4) were prepared through β-chlorination of 5,10,15,20-tetrakis(2-pyridyl)porphyrin (H2T-2-PyP) followed by N-ethylation and metallation. Metal centered redox potentials and superoxide dismutation activities were measured. Starting from MnTE-2-PyP5+, whose redox potential and the related superoxide dismutation activity were E°1/2 = +228 mV vs NHE and kcat = 5.7 × 107 M-1 s-1, respectively, the average increase of 55 mV in the redox potential per added chlorine was accompanied by a 65% increase in the rate constant. With E°1/2 = +448 mV, the tetrachlorinated derivative MnCl4TE-2-PyP5+ exhibited the highest superoxide dismuting rate kcat = 4.0 × 108 M-1 s-1. The relationship between the redox properties (thermodynamic and kinetic factors) and the superoxide dismuting activity of such compounds is discussed. © 1999 American Chemical Society.

Authors
Kachadourian, R; Batinić-Haberle, I; Fridovich, I
MLA Citation
Kachadourian, R, Batinić-Haberle, I, and Fridovich, I. "Syntheses and superoxide dismuting activities of partially (1-4) β-chlorinated derivatives of manganese(III) meso-tetrakis(N-ethylpyridinium-2-yl)porphyrin." Inorganic Chemistry 38.2 (1999): 391-396.
Source
scival
Published In
Inorganic Chemistry
Volume
38
Issue
2
Publish Date
1999
Start Page
391
End Page
396

The ortho effect makes manganese(III) meso-tetrakis(N-methylpyridinium-2-yl)porphyrin a powerful and potentially useful superoxide dismutase mimic.

The ortho, meta, and para isomers of manganese(III) 5,10,15, 20-tetrakis(N-methylpyridyl)porphyrin, MnTM-2-PyP5+, MnTM-3-PyP5+, and MnTM-4-PyP5+, respectively, were analyzed in terms of their superoxide dismutase (SOD) activity in vitro and in vivo. The impact of their interaction with DNA and RNA on the SOD activity in vivo and in vitro has also been analyzed. Differences in their behavior are due to the combined steric and electrostatic factors. In vitro catalytic activities are closely related to their redox potentials. The half-wave potentials (E1/2) are +0.220 mV, +0.052 mV, and +0.060 V versus normal hydrogen electrode, whereas the rates of dismutation (kcat) are 6.0 x 10(7), 4.1 x 10(6), and 3.8 x 10(6) M-1 s-1 for the ortho, meta, and para isomers, respectively. However, the in vitro activity is not a sufficient predictor of in vivo efficacy. The ortho and meta isomers, although of significantly different in vitro SOD activities, have fairly close in vivo SOD efficacy due to their similarly weak interactions with DNA. In contrast, due to a higher degree of interaction with DNA, the para isomer inhibited growth of SOD-deficient Escherichia coli.

Authors
Batinić-Haberle, I; Benov, L; Spasojević, I; Fridovich, I
MLA Citation
Batinić-Haberle, I, Benov, L, Spasojević, I, and Fridovich, I. "The ortho effect makes manganese(III) meso-tetrakis(N-methylpyridinium-2-yl)porphyrin a powerful and potentially useful superoxide dismutase mimic." J Biol Chem 273.38 (September 18, 1998): 24521-24528.
PMID
9733746
Source
pubmed
Published In
The Journal of biological chemistry
Volume
273
Issue
38
Publish Date
1998
Start Page
24521
End Page
24528

Lariat Ether Carboxylic Acids as Ionizable Hosts in the Second Coordination Sphere of the Siderophore Ferrioxamine B in Chloroform

A new series of lariat ether carboxylic acids (LnCOOH) was synthesized with different lengths of side arm (6, 9, and 12 atom spacers between the benzo-18-crown-6 crown ether ring and the carboxylic acid functional group). These lariat ethers were used as neutral and anionic hosts for the molecular recognition of the cationic siderophore, ferrioxamine B. Lariat ether pKa values were determined by potentiometric titration in 50% methanol (v/v) to be in the range 5.23-5.32. Molecular recognition of ferrioxamine B occurs through second-sphere complexation of the pendant protonated amine (-(CH2)5NH3+) by the lariat ether cavity, utilizing an ion-dipole host-guest interaction to form a supramolecular assembly in wet chloroform. At conditions where the pendant carboxylic acid side arm is not ionized (pH = 3.2), the lariat ethers behave as the parent unsubstituted crown ether structure, benzo-18-crown-6 (B18C6). At pH conditions well above their pKa values, the lariat ether carboxylic acids function both as a host and as an internal counterion. The stability of this binary assembly, {FeHDFB+,LnCOO-}, is significantly increased (log Kapp = 4.85 for L12COO-) compared with that of the ternary assembly involving the protonated lariat ether, {FeHDFB+,LnCOOH,ClO4-} (log K = 3.26 for L12COOH), or the parent crown ether, {FeHDFB+,B18C6,ClO4-} (log K = 3.21). Stability was also observed to increase with the length of the side arm from 6 (log Kapp = 4.29) to 12 atom spacers (log Kapp = 4.85). We attribute this effect to the increased conformational freedom of the longer arm, which facilitates interaction between the protonated amine site and the carboxylate moiety.

Authors
Batinić-Haberle, I; Spasojević, I; Jang, Y; Bartsch, RA; Crumbliss, AL
MLA Citation
Batinić-Haberle, I, Spasojević, I, Jang, Y, Bartsch, RA, and Crumbliss, AL. "Lariat Ether Carboxylic Acids as Ionizable Hosts in the Second Coordination Sphere of the Siderophore Ferrioxamine B in Chloroform." Inorganic Chemistry 37.7 (1998): 1438-1445.
Source
scival
Published In
Inorganic Chemistry
Volume
37
Issue
7
Publish Date
1998
Start Page
1438
End Page
1445

A potent superoxide dismutase mimic: manganese beta-octabromo-meso-tetrakis-(N-methylpyridinium-4-yl) porphyrin.

Variously modified metalloporphyrins offer a promising route to stable and active mimics of superoxide dismutase (SOD). Here we explore bromination on the pyrroles as a means of increasing the redox potentials and the catalytic activities of the copper and manganese complexes of a cationic porphyrin. Mn(II) and Cu(II) octabrominated 5,10,15,20-tetrakis-(N-methylpyridinium-4-yl) porphyrin, Mn(II)OBTMPyP4+, and Cu(II)OBTMPyP4+ were prepared and characterized. The rate constants for the porphyrin-catalyzed dismutation of O2.- as determined from the inhibition of the cytochrome c reduction are k(cat) = 2.2 x 10(8) and 2.9 x 10(6) M(-1) s(-1), i.e., IC50 was calculated to be 12 nM and 0.88 microM, respectively. The metal-centered half-wave potential was E(1/2) = +0.48 V vs NHE for the manganese compound. Cu(II)OBTMPyP4+ proved to be extremely stable, while its Mn(II) analog has a moderate stability, log K = 8.08. Nevertheless, slow manganese dissociation from Mn(II)OBTMPyP4+ enabled the complex to persist and exhibit catalytic activity even at the nanomolar concentration level and at biological pH. The corresponding Mn(III)OBTMPyP5+ complex exhibited significantly increased stability, i.e., demetallation was not detected in the presence of a 400-fold molar excess of EDTA at micromolar porphyrin concentration and at pH 7.8. The beta-substituted manganese porphyrin facilitated the growth of a SOD-deficient strain of Escherichia coli when present at 0.05 microM but was toxic at 1.0 microM. The synthetic approach used in the case of manganese and copper compounds offers numerous possibilities whereby the interplay of the type and of the number of beta substituents on the porphyrin ring would hopefully lead to porphyrin compounds of increased stability, catalytic activity, and decreased toxicity.

Authors
Batinić-Haberle, I; Liochev, SI; Spasojević, I; Fridovich, I
MLA Citation
Batinić-Haberle, I, Liochev, SI, Spasojević, I, and Fridovich, I. "A potent superoxide dismutase mimic: manganese beta-octabromo-meso-tetrakis-(N-methylpyridinium-4-yl) porphyrin." Arch Biochem Biophys 343.2 (July 15, 1997): 225-233.
PMID
9224734
Source
pubmed
Published In
Archives of Biochemistry and Biophysics
Volume
343
Issue
2
Publish Date
1997
Start Page
225
End Page
233
DOI
10.1006/abbi.1997.0157

Solvent effect on second-sphere coordination of ferrioxamine B with substituted 18-crown-6 and 30-crown-10 crown ethers in dichloromethane as compared to chloroform

Stability constants for the second-sphere association of picrate and perchlorate salts of ferrioxamine B (FeHDFB+) with the substituted crown ethers (CE) 18-crown-6, cis-dicyclohexano-18-crown-6, benzo-18-crown-6, dibenzo-18-crown-6 and dibenzo-30-crown-10 were determined in dichloromethane and compared with corresponding data collected in chloroform. The stability of the supramolecular assembly {FeHDFB+ ,CE,X-} is increased in wet CH2Cl2 compared to wet CHCl3 by 0.21 to 0.74 log units. This represents a deviation from the expected trend of higher host-guest stability constants in a less polar solvent. The complexity of the molecular recognition process is discussed in the context of the role of the solvent in relation to the role of the cation and anion, and their hydration shells, and the crown ether structure, in determining the stability of the supramolecular assembly.

Authors
Batinić-Haberle, I; Spasojević, I; Crumbliss, AL
MLA Citation
Batinić-Haberle, I, Spasojević, I, and Crumbliss, AL. "Solvent effect on second-sphere coordination of ferrioxamine B with substituted 18-crown-6 and 30-crown-10 crown ethers in dichloromethane as compared to chloroform." Inorganica Chimica Acta 260.1 (1997): 35-41.
Source
scival
Published In
Inorganica Chimica Acta
Volume
260
Issue
1
Publish Date
1997
Start Page
35
End Page
41

Second-Sphere Coordination of Ferrioxamine B and Association of Deferriferrioxamine B, CH(3)(CH(2))(4)NH(3)(+), NH(4)(+), K(+), and Mg(2+) with Synthetic Crown Ethers and the Natural Ionophores Valinomycin and Nonactin in Chloroform.

The interaction of ferrioxamine B, FeHDFB(+), through a protonated amine side chain, with various host ionophore structures to form a host-guest complex in the second coordination shell has been investigated. Host-guest association constants (K(a)) in water saturated chloroform are reported for synthetic crown ethers with different cavity size and substituents (18-crown-6 and its dicyclohexano, benzo, and dibenzo derivatives; dibenzo and dicyclohexano derivatives of 24-crown-8; and dibenzo-30-crown-10). The natural ionophores valinomycin and nonactin were also found to form stable second-sphere complexes with ferrioxamine B in wet chloroform. Results are reported for both picrate and perchlorate salts of FeHDFB(+). Since the protonated amine side chain of ferrioxamine B may be viewed as a substituted amine, the host-guest association constants for FeHDFB(+) are compared to the interaction of Mg(2+), K(+), NH(4)(+), CH(3)(CH(2))(4)NH(3)(+), and H(4)DFB(+) with the same ionophores. This is the first report of nonactin complexation of this series of cations in an organic medium of low polarity and one of the few reports of valinomycin complexation. To the best of our knowledge these are the first reported stability constants for the association of (Mg(2+),2pic(-)) with natural and synthetic ionophores in chloroform. K(a) values for ferrioxamine B complexation by the synthetic crown ethers are influenced by ring size and substituent. Despite significant preorganization capabilities, the large cavities of valinomycin, nonactin and benzo-30-crown-10 do not form as stable host-guest assemblies with bulky substituted amine cations such as ferrioxamine B as does cis-dicyclohexano-18-crown-6.

Authors
Batinic-Haberle, I; Spasojevic, I; Crumbliss, AL
MLA Citation
Batinic-Haberle, I, Spasojevic, I, and Crumbliss, AL. "Second-Sphere Coordination of Ferrioxamine B and Association of Deferriferrioxamine B, CH(3)(CH(2))(4)NH(3)(+), NH(4)(+), K(+), and Mg(2+) with Synthetic Crown Ethers and the Natural Ionophores Valinomycin and Nonactin in Chloroform." Inorg Chem 35.8 (April 10, 1996): 2352-2359.
PMID
11666435
Source
pubmed
Published In
Inorganic Chemistry
Volume
35
Issue
8
Publish Date
1996
Start Page
2352
End Page
2359

Molecular recognition of stable metal complexes through second-sphere coordination by macrocycles

An investigation of second coordination shell complexation of ferrioxamine B by crown ethers, natural ionophores, and other macrocycles through host-guest complexation of the pendant protonated amine group is presented. The influence of guest structure, host structure, solvation shell, and counter ion on host-guest assembly stability is discussed. Application of this form of molecular recognition to bulk liquid membrane transport of a stable metal complex is also presented. The significance of ionophore recognition of a metal complex in the context of iron bioavailability is discussed.

Authors
Crumbliss, AL; Batinić-Haberle, I; Spasojević, I
MLA Citation
Crumbliss, AL, Batinić-Haberle, I, and Spasojević, I. "Molecular recognition of stable metal complexes through second-sphere coordination by macrocycles." Pure and Applied Chemistry 68.6 (1996): 1225-1230.
Source
scival
Published In
Pure and applied chemistry. Chimie pure et appliquee
Volume
68
Issue
6
Publish Date
1996
Start Page
1225
End Page
1230

Second-Sphere Coordination of Ferrioxamine B and Association of Deferriferrioxamine B, CH3(CH2)4NH3+, NH4+, K+, and Mg2+ with Synthetic Crown Ethers and the Natural lonophores Valinomycin and Nonactin in Chloroform

The interaction of ferrioxamine B, FeHDFB+, through a protonated amine side chain, with various host ionophore structures to form a host-guest complex in the second coordination shell has been investigated. Host-guest association constants (Ka) in water saturated chloroform are reported for synthetic crown ethers with different cavity size and substituents (18-crown-6 and its dicyclohexano, benzo, and dibenzo derivatives; dibenzo and dicyclohexano derivatives of 24-crown-8; and dibenzo-30-crown-lO). The natural ionophores valinomycin and nonactin were also found to form stable second-sphere complexes with ferrioxamine B in wet chloroform. Results are reported for both picrate and perchlorate salts of FeHDFB+. Since the protonated amine side chain of ferrioxamine B may be viewed as a substituted amine, the host-guest association constants for FeHDFB+ are compared to the interaction of Mg2+, K+, NH4+, CH3(CH2)4NH3+, and H4DFB+ with the same ionophores. This is the first report of nonactin complexation of this series of cations in an organic medium of low polarity and one of the few reports of valinomycin complexation. To the best of our knowledge these are the first reported stability constants for the association of (Mg2+,2pic-) with natural and synthetic ionophores in chloroform. Ka values for ferrioxamine B complexation by the synthetic crown ethers are influenced by ring size and substituent. Despite significant preorganization capabilities, the large cavities of valinomycin, nonactin and benzo-30-crown-10 do not form as stable host-guest assemblies with bulky substituted amine cations such as ferrioxamine B as does cis-dicyclohexano-18-crown-6.

Authors
Batinic-Haberle, I; Spasojevié, I; Crumbliss, AL
MLA Citation
Batinic-Haberle, I, Spasojevié, I, and Crumbliss, AL. "Second-Sphere Coordination of Ferrioxamine B and Association of Deferriferrioxamine B, CH3(CH2)4NH3+, NH4+, K+, and Mg2+ with Synthetic Crown Ethers and the Natural lonophores Valinomycin and Nonactin in Chloroform." Inorganic Chemistry 35.8 (1996): 2352-2359.
Source
scival
Published In
Inorganic Chemistry
Volume
35
Issue
8
Publish Date
1996
Start Page
2352
End Page
2359

The effect of detergents on the reduction of tetrazolium salts.

Detergents, such as Triton X-100, markedly increase the reduction of tetrazolium salts by xanthine oxidase plus xanthine, or by NADH. This effect of detergent, in the case of the xanthine oxidase catalyzed process, is seen aerobically but not anaerobically. Increasing the rate of accumulation of formazan, whether by increasing the concentration of the tetrazolium salt or by adding detergent, decreased susceptibility to inhibition by superoxide dismutase or by O2. These results are accommodated by a scheme of reactions the essence of which is the univalent reduction of the tetrazolium to an uncharged tetrazoinyl radical which can reduce O2 to O2- or which can partition into the detergent micelles and there dismute to generate the stable formazan.

Authors
Liochev, SI; Batinic-Haberle, I; Fridovich, I
MLA Citation
Liochev, SI, Batinic-Haberle, I, and Fridovich, I. "The effect of detergents on the reduction of tetrazolium salts." Arch Biochem Biophys 324.1 (December 1, 1995): 48-52.
PMID
7503558
Source
pubmed
Published In
Archives of Biochemistry and Biophysics
Volume
324
Issue
1
Publish Date
1995
Start Page
48
End Page
52
DOI
10.1006/abbi.1995.9931

Stereochemical factors affecting second-sphere co-ordination of ferrioxamine B with cis-syn-cis and cis-anti-cis isomers of dicyclohexano-18-crown-6 in chloroform and a comparison with alkali-metal and ammonium cations

Second-sphere co-ordination of ferrioxamine B [Fe(HL)]+ by dicyclohexano-18-crown-6 (eicosahydrodibenzo[b,k][1,4,7,10,13,16]hexaoxacyclooctadecine) occurs through host-guest complex formation with the protonated amine side chain (CH2)5NH3+. The influence of steric factors on the association constants (Ka) for both nitrate and perchlorate salts of ferrioxamine B with cis-syn-cis and cis-anti-cis isomers of dicyclohexano-18-crown-6 (CE) in CHCl3 has been investigated. For comparison purposes, association of the perchlorate salt of the indium(III) analogue of ferrioxamine B [In(HL)]+ and the picrate salts of NH4+ and alkali-metal cations are included in this study (picrate = 2,4,6-trinitrophenolate). Although the absolute values of Ka for [M(HL)]X association with CE are strongly dependent on the anion identity, the selectivity ratio expressed for the syn crown ether isomer is 3:1 and is independent of anion variations. Comparison with alkali-metal and ammonium cations shows that the discrimination between syn and anti isomers of cis-dicyclohexano-18-crown-6 is dependent upon cation size and is the least for K+ where the ionic radius best matches the cavity size. While syn isomer discrimination in CHCl3 is closely related to the ionic radius, in water it is related to the hydrated radius. The syn over anti isomer preference exhibited by alkali-metal and ammonium cations is much more pronounced in water than in chloroform, which is likely due to the steric hindrance imposed by the large effective radius of the cations due to their hydration shell. Discrimination between the syn and anti isomers by [M(HL)]+ in CHCl3 is greater than expected based on comparison with the parent NH4+ ion. This is likely due to the significant steric requirements of the bulky metal complex molecule. The selectivity of the syn over the anti isomer is dominated by the preference of the bulky [M(HL)]+ complex for the less hindered face of the syn isomer.

Authors
Batinić-Haberle, I; Spasojević, I; Bartsch, RA; Crumbliss, AL
MLA Citation
Batinić-Haberle, I, Spasojević, I, Bartsch, RA, and Crumbliss, AL. "Stereochemical factors affecting second-sphere co-ordination of ferrioxamine B with cis-syn-cis and cis-anti-cis isomers of dicyclohexano-18-crown-6 in chloroform and a comparison with alkali-metal and ammonium cations." Journal of the Chemical Society, Dalton Transactions 15 (1995): 2503-2508.
Source
scival
Published In
Journal of the Chemical Society. Dalton Transactions
Issue
15
Publish Date
1995
Start Page
2503
End Page
2508
DOI
10.1039/DT9950002503

Influence of the anion on the stability of second-sphere coordination of ferrioxamine B with cis-dicyclohexano-18-crown-6 in chloroform

The influence of the anion X- on the stability of the supramolecular assembly FeHDFB+,CE,X- (I) where FeHDFB+ is ferrioxamine B, CE is dicyclohexano-18-crown-6, and X- is ClO4-, NO3-, Cl-, or picrate was investigated. The formation constants for these host-guest adducts in wet chloroform at 25°C were determined as follows: Ka(ClO4-) = 1.77 × 104 M-1, Ka(NO3-) = 1.34 × 102 M-1, Ka(Cl-) = 1.00 × 101 M-1, Ka(picrate) = 4.68 × 103 M-1. Distribution constants (Kd) for the ion pairs between water and chloroform, as well as extraction constants (Kex) for the corresponding crown ether separated ion pairs, were determined: Kd(ClO4-) = 3.10 × 10-4 M-1, Kd(NO3-) = 2.91 × 10-4 M-1, Kd(Cl-) = 3.00 × 10-4 M-1 , Kd(picrate) = 0.24; Kex(ClO4-) = 5.50 M-2, Kex(NO3-) = 3.91 × 10-2 M-2, Kex(Cl-) = 3.00 10-3 M-2, Kex(picrate) = 1.12 × 103 M-2. Data are presented which support the assertion that crown ether intercalation into the FeHDFB+,X- ion pair to form the supramolecular assembly in I provides a mechanism for the chloroform extraction process which is different from the distribution process. The importance of anion solvation in determining the stability of I is illustrated by a linear plot of log Ka vs anion hydration enthalpy. Comparison with our previously published data enable us to conclude that the stability of I is equally sensitive to hydration of the cation and the anion. We conclude that matching crown ether properties to the {cation,anion} combination in an ion pair may enhance host-guest interactions and optimize aqueous/organic phase extractions. © 1995 American Chemical Society.

Authors
Batinić-Haberle, I; Crumbliss, AL
MLA Citation
Batinić-Haberle, I, and Crumbliss, AL. "Influence of the anion on the stability of second-sphere coordination of ferrioxamine B with cis-dicyclohexano-18-crown-6 in chloroform." Inorganic Chemistry 34.4 (1995): 928-932.
Source
scival
Published In
Inorganic Chemistry
Volume
34
Issue
4
Publish Date
1995
Start Page
928
End Page
932

Influence of the various types of binder on the burning characteristics of the magnesium-, boron-, and aluminum-based igniters

The behaviour of six different types of binders phenol-formaldehyde resin, shellac, polyvinylchloride, ethylcellulose, nitrocellulose, and fluorel was investigated in pyrotechnic compositions on the basis of magnesium, boron and aluminum. It has been found that the nature of the binder significantly influences the burning characteristics of the igniters. Correlation has been found between binder exothermicity and investigated characteristics. In addition, the influence of the contents of phenol-formaldehyde resin and of fluorel, in the range of 0 % to 25 % on the same performance characteristics was studied. Phenol-formaldehyde resin has been chosen as preferred binder for the investigated igniters in an amount of 5 %.

Authors
Barisin, D; Batinic-Haberle, I
MLA Citation
Barisin, D, and Batinic-Haberle, I. "Influence of the various types of binder on the burning characteristics of the magnesium-, boron-, and aluminum-based igniters." Propellants, Explosives, Pyrotechnics 19.3 (1994): 127-132.
Source
scival
Published In
Propellants, Explosives, Pyrotechnics
Volume
19
Issue
3
Publish Date
1994
Start Page
127
End Page
132

Supramolecular assembly formation of ferrioxamine B and its Al(III), Ga(III), and In(III) analogues with dicyclohexano-18-crown-6 in chloroform

We have shown that the crown ether dicyclohexano-18-crown-6 recognizes the terminal amine group of deferriferrioxamine B (H4DFB+) and its Al(III), Ga(III), Fe(III), and In(III) complexes (MHDFB+) by host-guest complex formation. Host-guest formation constants for these supramolecular assemblies in chloroform at 25 °C were determined as follows: log Ka(H4DFB+) = 4.56, log Ka(AlHDFB+) = 3.48, log Ka(GaHDFB+) = 3.59, log Ka-(FeHDFB+) = 3.67, log Ka(InHDFB+) = 3.92. Chloroform extraction equilibrium constants (Kex) for the extraction of the MHDFB+ complexes and H4DFB+ in the presence of picrate anion by crown ether were determined as well as distribution constants (Kd) between a chloroform and aqueous phase in the absence of crown ether: log Kex(H4DFB+) = 2.89, log Kex(AlHDFB+) = 2.43, log Kex(GaHDFB+) = 2.84, log Kex(FeHDFB+) = 3.05, log Kex(InHDFB+) = 3.46; log Kd(H4DFB+) = -1.66, log Kd(AlHDFB+) = -1.05, log Kd(GaHDFB+) = -0.75, log Kd(FeHDFB+) = -0.62, log Kd(InHDFB+) = -0.46. In the series InHDFB+, FeHDFB+, GaHDFB+, and AlHDFB+ there is increasing hydration in the second coordination shell, as suggested by a linear relationship between log (Ka,KeX,Kd) and 1/ri (ri = M3+ radius) and M(H2O)63+ hydration enthalpy (ΔHhyd), which consequently increases hydrophilicity (decreases Kd) and increases steric hindrance to crown ether host-guest complex formation (decreases Ka). Correspondingly, the chloroform extraction constants (Kex = Kd·Ka), which depend on chloroform/water distribution (Kd) and host-guest complex formation (Ka), decrease in the same sequence. We conclude that the protonated amine of the free ligand H4DFB+ and its metal complexes provides a recognition site through formation of a supramolecular assembly with a crown ether. Second coordination shell effects (hydrophilicity) provide a mechanism to discriminate between different M(III) complexes of deferriferrioxamine B. The low Kd value obtained for deferriferrioxamine B distribution between the hydrophilic and lipophilic phase is consistent with previous reports concerning the therapeutic use of this ligand to remove intracellular iron from patients with iron overload.

Authors
Spasojević, I; Batinić-Haberle, I; Choo, PL; Crumbliss, AL
MLA Citation
Spasojević, I, Batinić-Haberle, I, Choo, PL, and Crumbliss, AL. "Supramolecular assembly formation of ferrioxamine B and its Al(III), Ga(III), and In(III) analogues with dicyclohexano-18-crown-6 in chloroform." Journal of the American Chemical Society 116.13 (1994): 5714-5721.
Source
scival
Published In
Journal of the American Chemical Society
Volume
116
Issue
13
Publish Date
1994
Start Page
5714
End Page
5721

Hydrolysis of ferrioxamine B in aqueous micellar solution

The association constant for the Fe(III) complex of the linear trihydroxamic acid siderophore ferrioxamine B (FeHDFB+; HDFB2- = H3N-[(CH2)5-N(O)C(O)-(CH2) 2C(O)NH-)]2(CH2)5-N(O)C(O)-CH 3) binding to sodium dodecyl sulfate (SDS) micelles was determined by ultrafiltration and kinetic methods. Both methods are in agreement and yield an average value of the association constant Km = 98 M-1. Association constants for the Al(III) analogue of ferrioxamine B, AlHDFB+, and of the metal-free ligand deferriferrioxamine B, H4DFB+, were also determined by ultrafiltration and found to be Km = 90 and 362 M-1, respectively. Ion-exchange constants (Kex) are calculated from Km values [Kex(FeHDFB+/Na+) = Kex(AlHDFB+/Na+) = 13; Kex(H4DFB+/Na+) = 46] and are discussed in relation to Kex for alkylammonium cations. Kinetic and thermodynamic parameters for the hydrolysis of ferrioxamine B in SDS solutions (0.01-0.15 M) at 25°C have been obtained by stopped-flow and spectrophotometric titration methods at I = 0.1 M (NaClO4/HClO4, NaNO3/HNO3) over a p[H+]tot range from 4.80 to 2.05. Good agreement is found between equilibrium constants determined by spectral and kinetic methods. Comparison with the parameters previously reported for the hydrolysis of FeHDFB+ in aqueous acidic solution suggests that FeHDFB+ resides in the Stern layer of the micelle, and consequently in a region of increased H+ concentration. Once a correction is made for the higher [H+] in the Stern layer, kinetic and thermodynamic parameters obtained in the presence of SDS micelles agree well with those reported for the reaction in aqueous medium. This agreement also gives additional support to the Km and Kex values obtained by ultrafiltration and kinetics. Results reported here show that there is no micellar stabilization of the siderophore complex. © 1994 American Chemical Society.

Authors
Batinić-Haberle, I; Spasojević, I; Crumbliss, AL
MLA Citation
Batinić-Haberle, I, Spasojević, I, and Crumbliss, AL. "Hydrolysis of ferrioxamine B in aqueous micellar solution." Inorganic Chemistry 33.14 (1994): 3151-3158.
Source
scival
Published In
Inorganic Chemistry
Volume
33
Issue
14
Publish Date
1994
Start Page
3151
End Page
3158

Functional and chemical characterization of the aging process of an igniter

The igniter consisting of 34% Mg, 60% KNO3, 3% KClO4 and 3% organic binder was subjected to accelerated aging under the conditions of 85% relative humidity at 65 °C, 75 °C and 85 °C, and at 75 °C with 92% relative humidity. Chemical aging was followed through formation of Mg(OH)2 and KNO2. Functional characterization was accomplished in a device constructed to enable simultaneous determination of the heat of combustion and pressure-time recording of the combustion process of both fresh and aged samples. The maximum acceptable deterioration occured at different times depending upon the conditions. The acceleration factor for every 10°C at 85% relative humidity is on average 2.8, leading to a prediction of shelf life of not more than 4 years at 25 °C. At the time when burning characteristics were significantly changed, the mixture suffered only slight chemical changes, with only about 1% Mg(OH)2 and 0.5% KNO2 being formed. Thus, no chemical changes should be tolerated in such formulations.

Authors
Spasojevic, I; Batinic-Haberle, I; Barisin, D
MLA Citation
Spasojevic, I, Batinic-Haberle, I, and Barisin, D. "Functional and chemical characterization of the aging process of an igniter." Propellants, Explosives, Pyrotechnics 18.2 (1993): 89-92.
Source
scival
Published In
Propellants, Explosives, Pyrotechnics
Volume
18
Issue
2
Publish Date
1993
Start Page
89
End Page
92

Stability characterization of the pyrotechnic system. The degradation of the nitrate oxidant in the presence of magnesium under the accelerated aging conditions

The degradation of the nitrate oxidant was followed in the course of the aging process of tracer pyrotechnic mix containing 22.0% Mg, 46.0% Sr(NO3)2, 22.0% KClO4, 9.0% Al-Mg alloy and 4.0% organic binder. The accelerated aging was conducted under the conditions of the increased humidity (98.5%, 85.0%, 78.5%) at the increased temperature (75°C). Nitrate content as a function of aging time was calculated by substracting nitrite nitrogen from total nitrogen content determined by Devarda's alloy reduction method. The degradation products of the nitrate (nitrite and carbonate) were determined by UV/VIS (Griess reaction) and IR spectroscopy, respectively. Nitrate proved to have a great instability in the presence of the metal, the extent of its conversion to nitrite and carbonate being rather great in comparison to the previously studied alkali metal nitrates in the presence of Mg as well. The loss of the nitrate and the formation of the nitrite and carbonate are governed by the same kinetic laws as fuel degradation to the hydroxide. The rate of the metal oxidation to the hydroxide was faster than the rate of the nitrate degradation process. The failure of the mix is connected to the rather small content of the nitrite (0.4%) while the texture was significantly destroyed.

Authors
Batinic-Haberle, I; Barisin, D; Spasojevic, I; Vranic, Z
MLA Citation
Batinic-Haberle, I, Barisin, D, Spasojevic, I, and Vranic, Z. "Stability characterization of the pyrotechnic system. The degradation of the nitrate oxidant in the presence of magnesium under the accelerated aging conditions." Propellants, Explosives, Pyrotechnics 17.1 (1992): 10-13.
Source
scival
Published In
Propellants, Explosives, Pyrotechnics
Volume
17
Issue
1
Publish Date
1992
Start Page
10
End Page
13

Siderophore chemistry of vanadium. Kinetics and equilibrium of interaction between vanadium(IV) and desferrioxamine B in aqueous acidic solutions

The kinetics and equilibrium of interaction between vanadyl sulfate and a natural trihydroxamate-based siderophore, desferrioxamine B methanesulfonate, were studied spectrophotometrically in acidic aqueous perchlorate solutions of 2.0 M ionic strength. The bi-, tetra-, and hexadentate-bonded complexes were formed under these conditions, and their stability constants were calculated. The rate constants for the formation and hydrolysis of the bi- and tetradentate complexes were estimated. The formation of the bidentate complex proceeds via two parallel pathways involving the hydrolyzed and unhydrolyzed vanadyl-aquo species. The hydrolyzed form was found to react with the siderophore ca. 105 times faster than the unhydrolyzed form. © 1991 American Chemical Society.

Authors
Batinić-Haberle, I; Biruš, M; Pribanić, M
MLA Citation
Batinić-Haberle, I, Biruš, M, and Pribanić, M. "Siderophore chemistry of vanadium. Kinetics and equilibrium of interaction between vanadium(IV) and desferrioxamine B in aqueous acidic solutions." Inorganic Chemistry 30.26 (1991): 4882-4887.
Source
scival
Published In
Inorganic Chemistry
Volume
30
Issue
26
Publish Date
1991
Start Page
4882
End Page
4887

Aging of pyrotechnic composition. The reliability of X-ray diffraction data for estimation of the quality of signal mix

The physical and chemical characteristics of green signal pyrotechnic mix, before and after destabilization caused by the action of increased humidity at different temperatures, were determined. Data obtained by means of X-ray diffraction, IR spectroscopy and adiabatic calorimetry were compared with the results acquired by measuring functional characteristics (the dominant wavelength and the color hue of the emitted light, the emission intensity and the burning rate). Comparison of all of these results points to the very close relationship between the X-ray diffraction data and the function of the signal mix. Chemical changes, leading to ineffectiveness of the examined mix, are the formation of Mg(OH)2, BaCO3 and Ba(NO2)2 with a concomittant decrease in the Mg and Ba(NO3)2 content. Since no changes were observed in separately aged components, the interaction among components proved to be decisive.

Authors
Barisin, D; Batinic-Haberle, I; Jovaniac, P
MLA Citation
Barisin, D, Batinic-Haberle, I, and Jovaniac, P. "Aging of pyrotechnic composition. The reliability of X-ray diffraction data for estimation of the quality of signal mix." Propellants, Explosives, Pyrotechnics 14.6 (1989): 255-259.
Source
scival
Published In
Propellants, Explosives, Pyrotechnics
Volume
14
Issue
6
Publish Date
1989
Start Page
255
End Page
259

Aging of pyrotechnic compositions. The investigation of chemical changes by IR spectroscopy and X-ray diffraction

The aging of tracers, containing different amounts of Mg, Sr(NO3)2, KClO4, Al-Mg alloy and organic binder, was conducted under the conditions of 50.0% and 98.5% relative humidities at 75°C, and of 98.5% relative humidity at 25°C. IR spectroscopy and X-ray diffraction were used for investigation of chemical changes. At the lower humidity no detectable changes were observed. Tracer of metal/oxidant ratio > 1 exhibits decreased stability, changing significantly under the conditions of higher humidity, even at room temperature. In the reaction sequence of the aging process (Mg(OH)2 and SrCO3 are formed, with a concomitant decrease in Mg and Sr(NO3)2 content. The alloy changes only slightly, and the content of KClO4 and binder remains unchanged. Interaction between metal and nitrate is considered to be essential in the process of chemical aging.

Authors
Barisim, D; Batinic-Haberle, I
MLA Citation
Barisim, D, and Batinic-Haberle, I. "Aging of pyrotechnic compositions. The investigation of chemical changes by IR spectroscopy and X-ray diffraction." Propellants, Explosives, Pyrotechnics 14.4 (1989): 162-169.
Source
scival
Published In
Propellants, Explosives, Pyrotechnics
Volume
14
Issue
4
Publish Date
1989
Start Page
162
End Page
169

METHOD OF OBTAINING GALLIUM FROM ALUMINATE SOLUTION BY ELECTROLYSIS.

The authors have sought a way of reclaiming gallium economically by electrolysis of a laboratory aluminate solution without having to use a cathode of mercury - an environmental pollutant. Cathodes of copper, indium, 70 In-30 Ga, Wood's alloy, and mercury (for comparison) were used with a wide range of anodes. The study accounted for the effects of electrode material, temperature, current density, and initial gallium concentration on the yield, energy consumption, and utilization of both current and electrode. The best results were obtained with indium or In-Ga cathodes and with platinum, Pt-Ti, or stainless steel anodes, at 75 degree C and a current density of approximately 100 A m** minus **2. Electrolysis was more efficient the higher the gallium concentration.

Authors
Jelacic, C; Barisin, D; Batinic-Haberle, I
MLA Citation
Jelacic, C, Barisin, D, and Batinic-Haberle, I. "METHOD OF OBTAINING GALLIUM FROM ALUMINATE SOLUTION BY ELECTROLYSIS." Materials Science and Technology 2.4 (1986): 416-419.
Source
scival
Published In
Materials Science and Technology
Volume
2
Issue
4
Publish Date
1986
Start Page
416
End Page
419
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