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Zhong, Xiaoping

Overview:

The immune system protects the host from microbial infection but can cause diseases if not properly controlled. My lab is interested in the receptor signaling mediated regulation of immune cell development and function as well as the pathogenesis and treatment of autoimmune diseases and allergies.

We are currently investigating the roles diacylglycerol kinases (DGKs) and TSC1/2-mTOR play in the immune system. DGKs are a family of ten enzymes that catalyze the conversion of diacylglycerol (DAG) to phosphatidic acid (PA), Both DAG and PA are important second messengers involved signaling from numerous receptors. While we expect DGKs to perform important roles in development and cellular function by modulating DAG and PA levels, the physiologic functions of DGKs have been poorly understood. Using cell line models and genetically manipulated mice, we have demonstrated that DGKα and ζ isoforms play critical roles in: T cell development, activation, and anergy by regulating T cell receptor signaling; FcεRI signaling and mast cell function; and Toll-like receptor signaling and innate immune responses.

Research areas that we are actively pursuing include:
1. The mechanisms that control T cell maturation, activation
and self-tolerance.
2. NKT cell development and function.
3. Thymic epithelial cells and thymic development, function, and involution.
4. Regulation of Toll-like receptor signaling and innate immunity. 
5. The pathogenesis and treatment of autoimmune hepatitis. 
6. Mast cell development and function.
7. The pathogenesis and immunotherapy for peanut allergy.

Positions:

Professor of Pediatrics

Pediatrics, Allergy and Immunology
School of Medicine

Professor of Immunology

Immunology
School of Medicine

Member of the Duke Cancer Institute

Duke Cancer Institute
School of Medicine

Education:

M.D. 1985

M.D. — First Medical College in Guangzhou (China)

Ph.D. 1997

Ph.D. — Duke University

Grants:

Research Training in Allergy and Clinical Immunology

Administered By
Pediatrics, Allergy and Immunology
AwardedBy
National Institutes of Health
Role
Mentor
Start Date
September 01, 2000
End Date
August 31, 2021

Organization and Function of Cellular Structure

Administered By
Basic Science Departments
AwardedBy
National Institutes of Health
Role
Mentor
Start Date
July 01, 1975
End Date
June 30, 2020

Regulating peripheral T cell tolerance

Administered By
Pediatrics, Allergy and Immunology
AwardedBy
National Institutes of Health
Role
Principal Investigator
Start Date
September 01, 2008
End Date
November 30, 2019

Basic Immunology Training Program

Administered By
Immunology
AwardedBy
National Institutes of Health
Role
Mentor
Start Date
July 01, 2002
End Date
June 30, 2019

TSC1-mTOR signaling and T cell tolerance

Administered By
Pediatrics, Allergy and Immunology
AwardedBy
National Institutes of Health
Role
Principal Investigator
Start Date
May 01, 2012
End Date
April 30, 2018

Duke Research Training Program for Pediatricians

Administered By
Pediatrics, Infectious Diseases
AwardedBy
National Institutes of Health
Role
Training Faculty
Start Date
July 01, 2002
End Date
April 30, 2018

A Murine Model of Chronic Autoimmune Hepatitis and Liver Fibrosis

Administered By
Pediatrics, Allergy and Immunology
AwardedBy
National Institutes of Health
Role
Principal Investigator
Start Date
July 01, 2008
End Date
June 30, 2014

Understanding the Mechanism of Mucosal Immunotherapy

Administered By
Pediatrics, Allergy and Immunology
AwardedBy
National Institutes of Health
Role
Co Investigator
Start Date
August 15, 2007
End Date
March 25, 2012

Prevention and Treatment of Cashew Allergy via Pepsinized Allergens

Administered By
Pediatrics, Allergy and Immunology
AwardedBy
National Institutes of Health
Role
Co-Mentor
Start Date
August 01, 2009
End Date
July 31, 2011

Immunotherapy for Peanut Allergy

Administered By
Pediatrics, Allergy and Immunology
AwardedBy
National Institutes of Health
Role
Principal Investigator
Start Date
July 01, 2008
End Date
September 30, 2010

Immunotherapy for Peanut Allergy

Administered By
Pediatrics, Allergy and Immunology
AwardedBy
National Institutes of Health
Role
Co Investigator
Start Date
September 01, 2005
End Date
August 31, 2008
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Publications:

Essential Role of mTORC1 in Self-Renewal of Murine Alveolar Macrophages.

Alveolar macrophages (AMϕ) have the capacity of local self-renewal through adult life; however, mechanisms that regulate AMϕ self-renewal remain poorly understood. We found that myeloid-specific deletion of Raptor, an essential component of the mammalian/mechanistic target of rapamycin complex (mTORC)1, resulted in a marked decrease of this population of cells accompanying altered phenotypic features and impaired phagocytosis activity. We demonstrated further that Raptor/mTORC1 deficiency did not affect AMϕ development, but compromised its proliferative activity at cell cycle entry in the steady-state as well as in the context of repopulation in irradiation chimeras. Mechanically, mTORC1 confers AMϕ optimal responsiveness to GM-CSF-induced proliferation. Thus, our results demonstrate an essential role of mTORC1 for AMϕ homeostasis by regulating proliferative renewal.

Authors
Deng, W; Yang, J; Lin, X; Shin, J; Gao, J; Zhong, X-P
MLA Citation
Deng, W, Yang, J, Lin, X, Shin, J, Gao, J, and Zhong, X-P. "Essential Role of mTORC1 in Self-Renewal of Murine Alveolar Macrophages." Journal of immunology (Baltimore, Md. : 1950) 198.1 (January 2017): 492-504.
PMID
27881705
Source
epmc
Published In
Journal of immunology (Baltimore, Md. : 1950)
Volume
198
Issue
1
Publish Date
2017
Start Page
492
End Page
504
DOI
10.4049/jimmunol.1501845

Vibrio vulnificus induces mTOR activation and inflammatory responses in macrophages.

Vibrio vulnificus (V. vulnificus), a Gram-negative marine bacterium, can cause life-threatening primary septicemia, especially in patients with liver diseases. How V. vulnificus affects the liver and how it acts on macrophages are not well understood. In this report, we demonstrated that V. vulnificus infection causes a strong inflammatory response, marked expansion of liver-resident macrophages, and liver damage in mice. We demonstrated further that V. vulnificus activates mTOR in macrophages and inhibition of mTOR differentially regulates V. vulnificus induced inflammatory responses, suggesting the possibility of targeting mTOR as a strategy to modulate V. vulnificus induced inflammatory responses.

Authors
Xie, D-L; Zheng, M-M; Zheng, Y; Gao, H; Zhang, J; Zhang, T; Guo, J-C; Yang, XF; Zhong, X-P; Lou, Y-L
MLA Citation
Xie, D-L, Zheng, M-M, Zheng, Y, Gao, H, Zhang, J, Zhang, T, Guo, J-C, Yang, XF, Zhong, X-P, and Lou, Y-L. "Vibrio vulnificus induces mTOR activation and inflammatory responses in macrophages." PloS one 12.7 (January 2017): e0181454-.
PMID
28719654
Source
epmc
Published In
PloS one
Volume
12
Issue
7
Publish Date
2017
Start Page
e0181454
DOI
10.1371/journal.pone.0181454

mTOR is critical for intestinal T-cell homeostasis and resistance to Citrobacter rodentium.

T-cells play an important role in promoting mucosal immunity against pathogens, but the mechanistic basis for their homeostasis in the intestine is still poorly understood. We report here that T-cell-specific deletion of mTOR results in dramatically decreased CD4 and CD8 T-cell numbers in the lamina propria of both small and large intestines under both steady-state and inflammatory conditions. These defects result in defective host resistance against a murine enteropathogen, Citrobacter rodentium, leading to the death of the animals. We further demonstrated that mTOR deficiency reduces the generation of gut-homing effector T-cells in both mesenteric lymph nodes and Peyer's patches without obviously affecting expression of gut-homing molecules on those effector T-cells. Using mice with T-cell-specific ablation of Raptor/mTORC1 or Rictor/mTORC2, we revealed that both mTORC1 and, to a lesser extent, mTORC2 contribute to both CD4 and CD8 T-cell accumulation in the gastrointestinal (GI) tract. Additionally, mTORC1 but not mTORC2 plays an important role regulating the proliferative renewal of both CD4 and CD8 T-cells in the intestines. Our data thus reveal that mTOR is crucial for T-cell accumulation in the GI tract and for establishing local adaptive immunity against pathogens.

Authors
Lin, X; Yang, J; Wang, J; Huang, H; Wang, H-X; Chen, P; Wang, S; Pan, Y; Qiu, Y-R; Taylor, GA; Vallance, BA; Gao, J; Zhong, X-P
MLA Citation
Lin, X, Yang, J, Wang, J, Huang, H, Wang, H-X, Chen, P, Wang, S, Pan, Y, Qiu, Y-R, Taylor, GA, Vallance, BA, Gao, J, and Zhong, X-P. "mTOR is critical for intestinal T-cell homeostasis and resistance to Citrobacter rodentium." Scientific reports 6 (October 12, 2016): 34939-.
PMID
27731345
Source
epmc
Published In
Scientific Reports
Volume
6
Publish Date
2016
Start Page
34939
DOI
10.1038/srep34939

Critical roles of mTOR Complex 1 and 2 for T follicular helper cell differentiation and germinal center responses.

T follicular helper (Tfh) cells play critical roles for germinal center responses and effective humoral immunity. We report here that mTOR in CD4 T cells is essential for Tfh differentiation. In Mtorf/f-Cd4Cre mice, both constitutive and inducible Tfh differentiation is severely impaired, leading to defective germinal center B cell formation and antibody production. Moreover, both mTORC1 and mTORC2 contribute to Tfh and GC B cell development but may do so via distinct mechanisms. mTORC1 mainly promotes CD4 T cell proliferation to reach the cell divisions necessary for Tfh differentiation, while Rictor/mTORC2 regulates Tfh differentiation by promoting Akt activation and TCF1 expression without grossly influencing T cell proliferation. Together, our results reveal crucial but distinct roles for mTORC1 and mTORC2 in CD4 T cells during Tfh differentiation and germinal center responses.

Authors
Yang, J; Lin, X; Pan, Y; Wang, J; Chen, P; Huang, H; Xue, H-H; Gao, J; Zhong, X-P
MLA Citation
Yang, J, Lin, X, Pan, Y, Wang, J, Chen, P, Huang, H, Xue, H-H, Gao, J, and Zhong, X-P. "Critical roles of mTOR Complex 1 and 2 for T follicular helper cell differentiation and germinal center responses." eLife 5 (September 30, 2016).
PMID
27690224
Source
epmc
Published In
eLife
Volume
5
Publish Date
2016
DOI
10.7554/elife.17936

Sustained activation of mTORC1 in macrophages increases AMPKα-dependent autophagy to maintain cellular homeostasis.

The mechanistic target of rapamycin complex 1 (mTORC1) is a well-conserved serine/threonine protein kinase that controls autophagy as well as many other processes such as protein synthesis, cell growth, and metabolism. The activity of mTORC1 is stringently and negatively controlled by the tuberous sclerosis proteins 1 and 2 complex (TSC1/2).In contrast to the previous studies using Tsc1 knockout mouse embryonic fibroblasts (MEF) cells, we demonstrated evidence that TSC1 deficient macrophages exhibited enhanced basal and mycobacterial infection-induced autophagy via AMPKα-dependent phosphorylation of ULK1 (Ser555). These effects were concomitant with constitutive activation of mTORC1 and can be reversed by addition of amino acids or rapamycin, and by the knockdown of the regulatory-associated protein of mTOR, Raptor. In addition, increased autophagy in TSC1 deficient macrophages resulted in suppression of inflammation during mycobacterial infection, which was reversed upon amino acid treatment of the TSC1 deficient macrophages. We further demonstrated that TSC1 conditional knockout mice infected with Mycobacterium tuberculosis, the causative agent of tuberculosis, resulted in less bacterial burden and a comparable level of inflammation when compared to wild type mice.Our data revealed that sustained activation of mTORC1 due to defects in TSC1 promotes AMPKα-dependent autophagic flux to maintain cellular homeostasis.

Authors
Pan, H; Zhong, X-P; Lee, S
MLA Citation
Pan, H, Zhong, X-P, and Lee, S. "Sustained activation of mTORC1 in macrophages increases AMPKα-dependent autophagy to maintain cellular homeostasis." BMC biochemistry 17.1 (July 7, 2016): 14-.
PMID
27387347
Source
epmc
Published In
BMC Biochemistry
Volume
17
Issue
1
Publish Date
2016
Start Page
14
DOI
10.1186/s12858-016-0069-6

Dominant Splice Site Mutations in PIK3R1 Cause Hyper IgM Syndrome, Lymphadenopathy and Short Stature.

The purpose of this research was to use next generation sequencing to identify mutations in patients with primary immunodeficiency diseases whose pathogenic gene mutations had not been identified. Remarkably, four unrelated patients were found by next generation sequencing to have the same heterozygous mutation in an essential donor splice site of PIK3R1 (NM_181523.2:c.1425 + 1G > A) found in three prior reports. All four had the Hyper IgM syndrome, lymphadenopathy and short stature, and one also had SHORT syndrome. They were investigated with in vitro immune studies, RT-PCR, and immunoblotting studies of the mutation's effect on mTOR pathway signaling. All patients had very low percentages of memory B cells and class-switched memory B cells and reduced numbers of naïve CD4+ and CD8+ T cells. RT-PCR confirmed the presence of both an abnormal 273 base-pair (bp) size and a normal 399 bp size band in the patient and only the normal band was present in the parents. Following anti-CD40 stimulation, patient's EBV-B cells displayed higher levels of S6 phosphorylation (mTOR complex 1 dependent event), Akt phosphorylation at serine 473 (mTOR complex 2 dependent event), and Akt phosphorylation at threonine 308 (PI3K/PDK1 dependent event) than controls, suggesting elevated mTOR signaling downstream of CD40. These observations suggest that amino acids 435-474 in PIK3R1 are important for its stability and also its ability to restrain PI3K activity. Deletion of Exon 11 leads to constitutive activation of PI3K signaling. This is the first report of this mutation and immunologic abnormalities in SHORT syndrome.

Authors
Petrovski, S; Parrott, RE; Roberts, JL; Huang, H; Yang, J; Gorentla, B; Mousallem, T; Wang, E; Armstrong, M; McHale, D; MacIver, NJ; Goldstein, DB; Zhong, X-P; Buckley, RH
MLA Citation
Petrovski, S, Parrott, RE, Roberts, JL, Huang, H, Yang, J, Gorentla, B, Mousallem, T, Wang, E, Armstrong, M, McHale, D, MacIver, NJ, Goldstein, DB, Zhong, X-P, and Buckley, RH. "Dominant Splice Site Mutations in PIK3R1 Cause Hyper IgM Syndrome, Lymphadenopathy and Short Stature." Journal of clinical immunology 36.5 (July 2016): 462-471.
Website
http://hdl.handle.net/10161/11947
PMID
27076228
Source
epmc
Published In
Journal of Clinical Immunology
Volume
36
Issue
5
Publish Date
2016
Start Page
462
End Page
471
DOI
10.1007/s10875-016-0281-6

mTORC2 in Thymic Epithelial Cells Controls Thymopoiesis and T Cell Development.

Thymic epithelial cells (TECs) play important roles in T cell generation. Mechanisms that control TEC development and function are still not well defined. The mammalian or mechanistic target of rapamycin complex (mTORC)2 signals to regulate cell survival, nutrient uptake, and metabolism. We report in the present study that mice with TEC-specific ablation of Rictor, a critical and unique adaptor molecule in mTORC2, display thymic atrophy, which accompanies decreased TEC numbers in the medulla. Moreover, generation of multiple T cell lineages, including conventional TCRαβ T cells, regulatory T cells, invariant NKT cells, and TCRγδ T cells, was reduced in TEC-specific Rictor-deficient mice. Our data demonstrate that mTORC2 in TECs is important for normal thymopoiesis and efficient T cell generation.

Authors
Wang, H-X; Cheng, JS; Chu, S; Qiu, Y-R; Zhong, X-P
MLA Citation
Wang, H-X, Cheng, JS, Chu, S, Qiu, Y-R, and Zhong, X-P. "mTORC2 in Thymic Epithelial Cells Controls Thymopoiesis and T Cell Development." Journal of immunology (Baltimore, Md. : 1950) 197.1 (July 2016): 141-150.
PMID
27233961
Source
epmc
Published In
Journal of immunology (Baltimore, Md. : 1950)
Volume
197
Issue
1
Publish Date
2016
Start Page
141
End Page
150
DOI
10.4049/jimmunol.1502698

Unexpected positive control of NFκB and miR-155 by DGKα and ζ ensures effector and memory CD8+ T cell differentiation.

Signals from the T-cell receptor (TCR) and γ-chain cytokine receptors play crucial roles in initiating activation and effector/memory differentiation of CD8 T-cells. We report here that simultaneous deletion of both diacylglycerol kinase (DGK) α and ζ (DKO) severely impaired expansion of CD8 effector T cells and formation of memory CD8 T-cells after Listeria monocytogenes infection. Moreover, ablation of both DGKα and ζ in preformed memory CD8 T-cells triggered death and impaired homeostatic proliferation of these cells. DKO CD8 T-cells were impaired in priming due to decreased expression of chemokine receptors and migration to the draining lymph nodes. Moreover, DKO CD8 T-cells were unexpectedly defective in NFκB-mediated miR-155 transcript, leading to excessive SOCS1 expression and impaired γ-chain cytokine signaling. Our data identified a DGK-NFκB-miR-155-SOCS1 axis that bridges TCR and γ-chain cytokine signaling for robust CD8 T-cell primary and memory responses to bacterial infection.

Authors
Yang, J; Zhang, P; Krishna, S; Wang, J; Lin, X; Huang, H; Xie, D; Gorentla, B; Huang, R; Gao, J; Li, Q-J; Zhong, X-P
MLA Citation
Yang, J, Zhang, P, Krishna, S, Wang, J, Lin, X, Huang, H, Xie, D, Gorentla, B, Huang, R, Gao, J, Li, Q-J, and Zhong, X-P. "Unexpected positive control of NFκB and miR-155 by DGKα and ζ ensures effector and memory CD8+ T cell differentiation." Oncotarget 7.23 (June 2016): 33744-33764.
PMID
27014906
Source
epmc
Published In
Oncotarget
Volume
7
Issue
23
Publish Date
2016
Start Page
33744
End Page
33764
DOI
10.18632/oncotarget.8164

mTORC1 in Thymic Epithelial Cells Is Critical for Thymopoiesis, T-Cell Generation, and Temporal Control of γδT17 Development and TCRγ/δ Recombination.

Thymus is crucial for generation of a diverse repertoire of T cells essential for adaptive immunity. Although thymic epithelial cells (TECs) are crucial for thymopoiesis and T cell generation, how TEC development and function are controlled is poorly understood. We report here that mTOR complex 1 (mTORC1) in TECs plays critical roles in thymopoiesis and thymus function. Acute deletion of mTORC1 in adult mice caused severe thymic involution. TEC-specific deficiency of mTORC1 (mTORC1KO) impaired TEC maturation and function such as decreased expression of thymotropic chemokines, decreased medullary TEC to cortical TEC ratios, and altered thymic architecture, leading to severe thymic atrophy, reduced recruitment of early thymic progenitors, and impaired development of virtually all T-cell lineages. Strikingly, temporal control of IL-17-producing γδT (γδT17) cell differentiation and TCRVγ/δ recombination in fetal thymus is lost in mTORC1KO thymus, leading to elevated γδT17 differentiation and rearranging of fetal specific TCRVγ/δ in adulthood. Thus, mTORC1 is central for TEC development/function and establishment of thymic environment for proper T cell development, and modulating mTORC1 activity can be a strategy for preventing thymic involution/atrophy.

Authors
Wang, H-X; Shin, J; Wang, S; Gorentla, B; Lin, X; Gao, J; Qiu, Y-R; Zhong, X-P
MLA Citation
Wang, H-X, Shin, J, Wang, S, Gorentla, B, Lin, X, Gao, J, Qiu, Y-R, and Zhong, X-P. "mTORC1 in Thymic Epithelial Cells Is Critical for Thymopoiesis, T-Cell Generation, and Temporal Control of γδT17 Development and TCRγ/δ Recombination." PLoS biology 14.2 (February 18, 2016): e1002370-.
PMID
26889835
Source
epmc
Published In
PLoS biology
Volume
14
Issue
2
Publish Date
2016
Start Page
e1002370
DOI
10.1371/journal.pbio.1002370

Intercellular Protein Transfer from Thymocytes to Thymic Epithelial Cells.

Promiscuous expression of tissue restricted antigens (TRAs) in medullary thymic epithelial cells (mTECs) is crucial for negative selection of self-reactive T cells to establish central tolerance. Intercellular transfer of self-peptide-MHC complexes from mTECs to thymic dendritic cells (DCs) allows DCs to acquire TRAs, which in turn contributes to negative selection and regulatory T cell generation. However, mTECs are unlikely to express all TRAs, such as immunoglobulins generated only in B cells after somatic recombination, hyper-mutation, or class-switches. We report here that both mTECs and cortical TECs can efficiently acquire not only cell surface but also intracellular proteins from thymocytes. This reveals a previously unappreciated intercellular sharing of molecules from thymocytes to TECs, which may broaden the TRA inventory in mTECs for establishing a full spectrum of central tolerance.

Authors
Wang, H-X; Qiu, Y-R; Zhong, X-P
MLA Citation
Wang, H-X, Qiu, Y-R, and Zhong, X-P. "Intercellular Protein Transfer from Thymocytes to Thymic Epithelial Cells." PloS one 11.3 (January 2016): e0152641-.
Website
http://hdl.handle.net/10161/11812
PMID
27022746
Source
epmc
Published In
PloS one
Volume
11
Issue
3
Publish Date
2016
Start Page
e0152641
DOI
10.1371/journal.pone.0152641

Diacylglycerol Kinases in T Cell Tolerance and Effector Function.

Diacylglycerol kinases (DGKs) are a family of enzymes that regulate the relative levels of diacylglycerol (DAG) and phosphatidic acid (PA) in cells by phosphorylating DAG to produce PA. Both DAG and PA are important second messengers cascading T cell receptor (TCR) signal by recruiting multiple effector molecules, such as RasGRP1, PKCθ, and mTOR. Studies have revealed important physiological functions of DGKs in the regulation of receptor signaling and the development and activation of immune cells. In this review, we will focus on recent progresses in our understanding of two DGK isoforms, α and ζ, in CD8 T effector and memory cell differentiation, regulatory T cell development and function, and invariant NKT cell development and effector lineage differentiation.

Authors
Chen, SS; Hu, Z; Zhong, X-P
MLA Citation
Chen, SS, Hu, Z, and Zhong, X-P. "Diacylglycerol Kinases in T Cell Tolerance and Effector Function." Frontiers in cell and developmental biology 4 (January 2016): 130-. (Review)
PMID
27891502
Source
epmc
Published In
Frontiers in Cell and Developmental Biology
Volume
4
Publish Date
2016
Start Page
130

mTOR and its tight regulation for iNKT cell development and effector function.

Invariant NKT (iNKT) cells, which express the invariant Vα14Jα18 TCR that recognizes lipid antigens, have the ability to rapidly respond to agonist stimulation, producing a variety of cytokines that can shape both innate and adaptive immunity. iNKT cells have been implicated in host defense against microbial infection, in anti-tumor immunity, and a multitude of diseases such as allergies, asthma, graft versus host disease, and obesity. Emerging evidence has demonstrated crucial role for mammalian target of rapamycin (mTOR) in immune cells, including iNKT. In this review we will discuss current understanding of how mTOR and its tight regulation control iNKT cell development, effector lineage differentiation, and function.

Authors
Yang, W; Gorentla, B; Zhong, X-P; Shin, J
MLA Citation
Yang, W, Gorentla, B, Zhong, X-P, and Shin, J. "mTOR and its tight regulation for iNKT cell development and effector function." Molecular immunology 68.2 Pt C (December 2015): 536-545. (Review)
PMID
26253278
Source
epmc
Published In
Molecular Immunology
Volume
68
Issue
2 Pt C
Publish Date
2015
Start Page
536
End Page
545
DOI
10.1016/j.molimm.2015.07.022

TSC1 Promotes B Cell Maturation but Is Dispensable for Germinal Center Formation.

Accumulating evidence indicates that the tuberous sclerosis complex 1 (TSC1), a tumor suppressor that acts by inhibiting mTOR signaling, plays an important role in the immune system. We report here that TSC1 differentially regulates mTOR complex 1 (mTORC1) and mTORC2/Akt signaling in B cells. TSC1 deficiency results in the accumulation of transitional-1 (T1) B cells and progressive losses of B cells as they mature beyond the T1 stage. Moreover, TSC1KO mice exhibit a mild defect in the serum antibody responses or rate of Ig class-switch recombination after immunization with a T-cell-dependent antigen. In contrast to a previous report, we demonstrate that both constitutive Peyer's patch germinal centers (GCs) and immunization-induced splenic GCs are unimpaired in TSC1-deficient (TSC1KO) mice and that the ratio of GC B cells to total B cells is comparable in WT and TSC1KO mice. Together, our data demonstrate that TSC1 plays important roles for B cell development, but it is dispensable for GC formation and serum antibody responses.

Authors
Ci, X; Kuraoka, M; Wang, H; Carico, Z; Hopper, K; Shin, J; Deng, X; Qiu, Y; Unniraman, S; Kelsoe, G; Zhong, X-P
MLA Citation
Ci, X, Kuraoka, M, Wang, H, Carico, Z, Hopper, K, Shin, J, Deng, X, Qiu, Y, Unniraman, S, Kelsoe, G, and Zhong, X-P. "TSC1 Promotes B Cell Maturation but Is Dispensable for Germinal Center Formation." PloS one 10.5 (January 2015): e0127527-.
Website
http://hdl.handle.net/10161/10894
PMID
26000908
Source
epmc
Published In
PloS one
Volume
10
Issue
5
Publish Date
2015
Start Page
e0127527
DOI
10.1371/journal.pone.0127527

IKKα negatively regulates ASC-dependent inflammasome activation.

The inflammasomes are multiprotein complexes that activate caspase-1 in response to infections and stress, resulting in the secretion of pro-inflammatory cytokines. Here we report that IκB kinase α (IKKα) is a critical negative regulator of apoptosis-associated specklike protein containing a C-terminal caspase-activation-andrecruitment (CARD) domain (ASC)-dependent inflammasomes. IKKα controls the inflammasome at the level of the adaptor ASC, which interacts with IKKα in the nucleus of resting macrophages in an IKKα kinase-dependent manner. Loss of IKKα kinase activity results in inflammasome hyperactivation. Mechanistically, the downstream nuclear effector IKK-related kinase (IKKi) facilitates translocation of ASC from the nucleus to the perinuclear area during inflammasome activation. ASC remains under the control of IKKα in the perinuclear area following translocation of the ASC/IKKα complex. Signal 2 of NLRP3 activation leads to inhibition of IKKα kinase activity through the recruitment of PP2A, allowing ASC to participate in NLRP3 inflammasome assembly. Taken together, these findings reveal a IKKi-IKKα-ASC axis that serves as a common regulatory mechanism for ASC-dependent inflammasomes.

Authors
Martin, BN; Wang, C; Willette-Brown, J; Herjan, T; Gulen, MF; Zhou, H; Bulek, K; Franchi, L; Sato, T; Alnemri, ES; Narla, G; Zhong, X-P; Thomas, J; Klinman, D; Fitzgerald, KA; Karin, M; Nuñez, G; Dubyak, G; Hu, Y; Li, X
MLA Citation
Martin, BN, Wang, C, Willette-Brown, J, Herjan, T, Gulen, MF, Zhou, H, Bulek, K, Franchi, L, Sato, T, Alnemri, ES, Narla, G, Zhong, X-P, Thomas, J, Klinman, D, Fitzgerald, KA, Karin, M, Nuñez, G, Dubyak, G, Hu, Y, and Li, X. "IKKα negatively regulates ASC-dependent inflammasome activation." Nature communications 5 (September 30, 2014): 4977-.
PMID
25266676
Source
epmc
Published In
Nature Communications
Volume
5
Publish Date
2014
Start Page
4977
DOI
10.1038/ncomms5977

A nonsense mutation in IKBKB causes combined immunodeficiency.

Identification of the molecular etiologies of primary immunodeficiencies has led to important insights into the development and function of the immune system. We report here the cause of combined immunodeficiency in 4 patients from 2 different consanguineous Qatari families with similar clinical and immunologic phenotypes. The patients presented at an early age with fungal, viral, and bacterial infections and hypogammaglobulinemia. Although their B- and T-cell numbers were normal, they had low regulatory T-cell and NK-cell numbers. Moreover, patients' T cells were mostly CD45RA(+)-naive cells and were defective in activation after T-cell receptor stimulation. All patients contained the same homozygous nonsense mutation in IKBKB (R286X), revealed by whole-exome sequencing with undetectable IKKβ and severely decreased NEMO proteins. Mutant IKKβ(R286X) was unable to complex with IKKα/NEMO. Immortalized patient B cells displayed impaired IκBα phosphorylation and NFκB nuclear translocation. These data indicate that mutated IKBKB is the likely cause of immunodeficiency in these 4 patients.

Authors
Mousallem, T; Yang, J; Urban, TJ; Wang, H; Adeli, M; Parrott, RE; Roberts, JL; Goldstein, DB; Buckley, RH; Zhong, X-P
MLA Citation
Mousallem, T, Yang, J, Urban, TJ, Wang, H, Adeli, M, Parrott, RE, Roberts, JL, Goldstein, DB, Buckley, RH, and Zhong, X-P. "A nonsense mutation in IKBKB causes combined immunodeficiency." Blood 124.13 (September 2014): 2046-2050.
PMID
25139357
Source
epmc
Published In
Blood
Volume
124
Issue
13
Publish Date
2014
Start Page
2046
End Page
2050
DOI
10.1182/blood-2014-04-571265

Role of tumor suppressor TSC1 in regulating antigen-specific primary and memory CD8 T cell responses to bacterial infection.

The serine/threonine kinase mammalian/mechanistic target of rapamycin (mTOR) integrates various environmental cues such as the presence of antigen, inflammation, and nutrients to regulate T cell growth, metabolism, and function. The tuberous sclerosis 1 (TSC1)/TSC2 complex negatively regulates the activity of an mTOR-containing multiprotein complex called mTOR complex 1. Recent studies have revealed an essential cell-intrinsic role for TSC1 in T cell survival, quiescence, and mitochondrial homeostasis. Given the emerging role of mTOR activity in the regulation of the quantity and quality of CD8 T cell responses, in this study, we examine the role of its suppressor, TSC1, in the regulation of antigen-specific primary and memory CD8 T cell responses to bacterial infection. Using an established model system of transgenic CD8 cell adoptive transfer and challenge with Listeria monocytogenes expressing a cognate antigen, we found that TSC1 deficiency impairs antigen-specific CD8 T cell responses, resulting in weak expansion, exaggerated contraction, and poor memory generation. Poor expansion of TSC1-deficient cells was associated with defects in survival and proliferation in vivo, while enhanced contraction was correlated with an increased ratio of short-lived effectors to memory precursors in the effector cell population. This perturbation of effector-memory differentiation was concomitant with decreased expression of eomesodermin among activated TSC1 knockout cells. Upon competitive adoptive transfer with wild-type counterparts and antigen rechallenge, TSC1-deficient memory cells showed moderate defects in expansion but not cytokine production. Taken together, these findings provide direct evidence of a CD8 T cell-intrinsic role for TSC1 in the regulation of antigen-specific primary and memory responses.

Authors
Krishna, S; Yang, J; Wang, H; Qiu, Y; Zhong, X-P
MLA Citation
Krishna, S, Yang, J, Wang, H, Qiu, Y, and Zhong, X-P. "Role of tumor suppressor TSC1 in regulating antigen-specific primary and memory CD8 T cell responses to bacterial infection." Infection and immunity 82.7 (July 2014): 3045-3057.
PMID
24818661
Source
epmc
Published In
Infection and immunity
Volume
82
Issue
7
Publish Date
2014
Start Page
3045
End Page
3057
DOI
10.1128/iai.01816-14

T cell receptor-dependent activation of mTOR signaling in T cells is mediated by Carma1 and MALT1, but not Bcl10.

Signaling to the mechanistic target of rapamycin (mTOR) regulates diverse cellular processes, including protein translation, cellular proliferation, metabolism, and autophagy. Most models place Akt upstream of the mTOR complex, mTORC1; however, in T cells, Akt may not be necessary for mTORC1 activation. We found that the adaptor protein Carma1 [caspase recruitment domain (CARD)-containing membrane-associated protein 1] and at least one of its associated proteins, the paracaspase MALT1 (mucosa-associated lymphoid tissue lymphoma translocation protein 1), were required for optimal activation of mTOR in T cells in response to stimulation of the T cell receptor (TCR) and the co-receptor CD28. However, Bcl10, which binds to Carma1 and MALT1 to form a complex that mediates signals from the TCR to the transcription factor NF-κB (nuclear factor κB), was not required. The catalytic activity of MALT1 was required for the proliferation of stimulated CD4+ T cells, but not for early TCR-dependent activation events. Consistent with an effect on mTOR, MALT1 activity was required for the increased metabolic flux in activated CD4+ T cells. Together, our data suggest that Carma1 and MALT1 play previously unappreciated roles in the activation of mTOR signaling in T cells after engagement of the TCR.

Authors
Hamilton, KS; Phong, B; Corey, C; Cheng, J; Gorentla, B; Zhong, X; Shiva, S; Kane, LP
MLA Citation
Hamilton, KS, Phong, B, Corey, C, Cheng, J, Gorentla, B, Zhong, X, Shiva, S, and Kane, LP. "T cell receptor-dependent activation of mTOR signaling in T cells is mediated by Carma1 and MALT1, but not Bcl10." Science signaling 7.329 (June 10, 2014): ra55-.
PMID
24917592
Source
epmc
Published In
Science Signaling
Volume
7
Issue
329
Publish Date
2014
Start Page
ra55
DOI
10.1126/scisignal.2005169

iNKT cells require TSC1 for terminal maturation and effector lineage fate decisions.

Terminal maturation of invariant NKT (iNKT) cells from stage 2 (CD44+NK1.1-) to stage 3 (CD44+NK1.1+) is accompanied by a functional acquisition of a predominant IFN-γ-producing (iNKT-1) phenotype; however, some cells develop into IL-17-producing iNKT (iNKT-17) cells. iNKT-17 cells are rare and restricted to a CD44+NK1.1- lineage. It is unclear how iNKT terminal maturation is regulated and what factors mediate the predominance of iNKT-1 compared with iNKT-17. The tumor suppressor tuberous sclerosis 1 (TSC1) is an important negative regulator of mTOR signaling, which regulates T cell differentiation, function, and trafficking. Here, we determined that mice lacking TSC1 exhibit a developmental block of iNKT differentiation at stage 2 and skew from a predominantly iNKT-1 population toward a predominantly iNKT-17 population, leading to enhanced airway hypersensitivity. Evaluation of purified iNKT cells revealed that TSC1 promotes T-bet, which regulates iNKT maturation, but downregulates ICOS expression in iNKT cells by inhibiting mTOR complex 1 (mTORC1). Furthermore, mice lacking T-bet exhibited both a terminal maturation defect of iNKT cells and a predominance of iNKT-17 cells, and increased ICOS expression was required for the predominance of iNKT-17 cells in the population of TSC1-deficient iNKT cells. Our data indicate that TSC1-dependent control of mTORC1 is crucial for terminal iNKT maturation and effector lineage decisions, resulting in the predominance of iNKT-1 cells.

Authors
Wu, J; Yang, J; Yang, K; Wang, H; Gorentla, B; Shin, J; Qiu, Y; Que, LG; Foster, WM; Xia, Z; Chi, H; Zhong, X-P
MLA Citation
Wu, J, Yang, J, Yang, K, Wang, H, Gorentla, B, Shin, J, Qiu, Y, Que, LG, Foster, WM, Xia, Z, Chi, H, and Zhong, X-P. "iNKT cells require TSC1 for terminal maturation and effector lineage fate decisions." The Journal of clinical investigation 124.4 (April 2014): 1685-1698.
PMID
24614103
Source
epmc
Published In
Journal of Clinical Investigation
Volume
124
Issue
4
Publish Date
2014
Start Page
1685
End Page
1698
DOI
10.1172/jci69780

Tuberous sclerosis 1 promotes invariant NKT cell anergy and inhibits invariant NKT cell-mediated antitumor immunity.

Development of effective immune therapies for cancer patients requires better understanding of hurdles that prevent the generation of effective antitumor immune responses. Administration of α-galactosylceramide (α-GalCer) in animals enhances antitumor immunity via activation of the invariant NKT (iNKT) cells. However, repeated injections of α-GalCer result in long-term unresponsiveness or anergy of iNKT cells, severely limiting its efficacy in tumor eradication. The mechanisms leading to iNKT cell anergy remain poorly understood. We report in this study that the tuberous sclerosis 1 (TSC1), a negative regulator of mTOR signaling, plays a crucial role in iNKT cell anergy. Deficiency of TSC1 in iNKT cells results in resistance to α-GalCer-induced anergy, manifested by increased expansion of and cytokine production by iNKT cells in response to secondary Ag stimulation. It is correlated with impaired upregulation of programmed death-1, Egr2, and Grail. Moreover, TSC1-deficient iNKT cells display enhanced antitumor immunity in a melanoma lung metastasis model. Our data suggest targeting TSC1/2 as a strategy for boosting antitumor immune therapy.

Authors
Wu, J; Shin, J; Xie, D; Wang, H; Gao, J; Zhong, X-P
MLA Citation
Wu, J, Shin, J, Xie, D, Wang, H, Gao, J, and Zhong, X-P. "Tuberous sclerosis 1 promotes invariant NKT cell anergy and inhibits invariant NKT cell-mediated antitumor immunity." Journal of immunology (Baltimore, Md. : 1950) 192.6 (March 2014): 2643-2650.
PMID
24532578
Source
epmc
Published In
Journal of immunology (Baltimore, Md. : 1950)
Volume
192
Issue
6
Publish Date
2014
Start Page
2643
End Page
2650
DOI
10.4049/jimmunol.1302076

Mechanistic target of rapamycin complex 1 is critical for invariant natural killer T-cell development and effector function.

The mechanisms that control invariant natural killer T (iNKT)-cell development and function are still poorly understood. The mechanistic or mammalian target of rapamycin (mTOR) integrates various environmental signals/cues to regulate cell growth, proliferation, metabolism, and survival. We report here that ablation of mTOR complex 1 (mTORC1) signaling by conditionally deleting Raptor causes severe defects in iNKT-cell development at early stages, leading to drastic reductions in iNKT-cell numbers in the thymus and periphery. In addition, loss of Raptor impairs iNKT-cell proliferation and production of cytokines upon α-galactosylceramide stimulation in vitro and in vivo, and inhibits liver inflammation in an iNKT cell-mediated hepatitis model. Furthermore, Raptor deficiency and rapamycin treatment lead to aberrant intracellular localization and functional impairment of promyelocytic leukemia zinc-finger, a transcription factor critical for iNKT-cell development and effector programs. Our findings define an essential role of mTORC1 to direct iNKT-cell lineage development and effector function.

Authors
Shin, J; Wang, S; Deng, W; Wu, J; Gao, J; Zhong, X-P
MLA Citation
Shin, J, Wang, S, Deng, W, Wu, J, Gao, J, and Zhong, X-P. "Mechanistic target of rapamycin complex 1 is critical for invariant natural killer T-cell development and effector function." Proceedings of the National Academy of Sciences of the United States of America 111.8 (February 10, 2014): E776-E783.
PMID
24516149
Source
epmc
Published In
Proceedings of the National Academy of Sciences of USA
Volume
111
Issue
8
Publish Date
2014
Start Page
E776
End Page
E783
DOI
10.1073/pnas.1315435111

Whole-Exome Sequencing Reveals IKBKB As a Cause of Combined Immunodeficiency

Authors
Mousallem, T; Yang, J; Urban, TJ; Wang, H; Parrott, RE; Roberts, JL; Buckley, RH; Zhong, X; Goldstein, DB
MLA Citation
Mousallem, T, Yang, J, Urban, TJ, Wang, H, Parrott, RE, Roberts, JL, Buckley, RH, Zhong, X, and Goldstein, DB. "Whole-Exome Sequencing Reveals IKBKB As a Cause of Combined Immunodeficiency." February 2014.
Source
wos-lite
Published In
Journal of Allergy and Clinical Immunology
Volume
133
Issue
2
Publish Date
2014
Start Page
AB399
End Page
AB399

The role of diacylglycerol kinase ζ and phosphatidic acid in the mechanical activation of mammalian target of rapamycin (mTOR) signaling and skeletal muscle hypertrophy.

The activation of mTOR signaling is essential for mechanically induced changes in skeletal muscle mass, and previous studies have suggested that mechanical stimuli activate mTOR (mammalian target of rapamycin) signaling through a phospholipase D (PLD)-dependent increase in the concentration of phosphatidic acid (PA). Consistent with this conclusion, we obtained evidence which further suggests that mechanical stimuli utilize PA as a direct upstream activator of mTOR signaling. Unexpectedly though, we found that the activation of PLD is not necessary for the mechanically induced increases in PA or mTOR signaling. Motivated by this observation, we performed experiments that were aimed at identifying the enzyme(s) that promotes the increase in PA. These experiments revealed that mechanical stimulation increases the concentration of diacylglycerol (DAG) and the activity of DAG kinases (DGKs) in membranous structures. Furthermore, using knock-out mice, we determined that the ζ isoform of DGK (DGKζ) is necessary for the mechanically induced increase in PA. We also determined that DGKζ significantly contributes to the mechanical activation of mTOR signaling, and this is likely driven by an enhanced binding of PA to mTOR. Last, we found that the overexpression of DGKζ is sufficient to induce muscle fiber hypertrophy through an mTOR-dependent mechanism, and this event requires DGKζ kinase activity (i.e. the synthesis of PA). Combined, these results indicate that DGKζ, but not PLD, plays an important role in mechanically induced increases in PA and mTOR signaling. Furthermore, this study suggests that DGKζ could be a fundamental component of the mechanism(s) through which mechanical stimuli regulate skeletal muscle mass.

Authors
You, J-S; Lincoln, HC; Kim, C-R; Frey, JW; Goodman, CA; Zhong, X-P; Hornberger, TA
MLA Citation
You, J-S, Lincoln, HC, Kim, C-R, Frey, JW, Goodman, CA, Zhong, X-P, and Hornberger, TA. "The role of diacylglycerol kinase ζ and phosphatidic acid in the mechanical activation of mammalian target of rapamycin (mTOR) signaling and skeletal muscle hypertrophy." J Biol Chem 289.3 (January 17, 2014): 1551-1563.
PMID
24302719
Source
pubmed
Published In
The Journal of biological chemistry
Volume
289
Issue
3
Publish Date
2014
Start Page
1551
End Page
1563
DOI
10.1074/jbc.M113.531392

Mechanistic target of rapamycin complex 1 is critical for invariant natural killer T-cell development and effector function

The mechanisms that control invariant natural killer T (iNKT)-cell development and function are still poorly understood. The mechanistic or mammalian target of rapamycin (mTOR) integrates various environmental signals/cues to regulate cell growth, proliferation, metabolism, and survival. We report here that ablation of mTOR complex 1 (mTORC1) signaling by conditionally deleting Raptor causes severe defects in iNKT-cell development at early stages, leading to drastic reductions in iNKT-cell numbers in the thymus and periphery. In addition, loss of Raptor impairs iNKT-cell proliferation and production of cytokines upon α-galactosylceramide stimulation in vitro and in vivo, and inhibits liver inflammation in an iNKT cell-mediated hepatitis model. Furthermore, Raptor deficiency and rapamycin treatment lead to aberrant intracellular localization and functional impairment of promyelocytic leukemia zinc-finger, a transcription factor critical for iNKT-cell development and effector programs. Our findings define an essential role of mTORC1 to direct iNKT-cell lineage development and effector function.

Authors
Shin, J; Wang, S; Deng, W; Wu, J; Gao, J; Zhong, X-P
MLA Citation
Shin, J, Wang, S, Deng, W, Wu, J, Gao, J, and Zhong, X-P. "Mechanistic target of rapamycin complex 1 is critical for invariant natural killer T-cell development and effector function." Proceedings of the National Academy of Sciences of the United States of America 111.8 (2014): E766-E783.
Source
scival
Published In
Proceedings of the National Academy of Sciences of USA
Volume
111
Issue
8
Publish Date
2014
Start Page
E766
End Page
E783
DOI
10.1073/pnas.1315435111

Mechanistic target of rapamycin complex 1 is critical for invariant natural killer T-cell development and effector function.

The mechanisms that control invariant natural killer T (iNKT)-cell development and function are still poorly understood. The mechanistic or mammalian target of rapamycin (mTOR) integrates various environmental signals/cues to regulate cell growth, proliferation, metabolism, and survival. We report here that ablation of mTOR complex 1 (mTORC1) signaling by conditionally deleting Raptor causes severe defects in iNKT-cell development at early stages, leading to drastic reductions in iNKT-cell numbers in the thymus and periphery. In addition, loss of Raptor impairs iNKT-cell proliferation and production of cytokines upon α-galactosylceramide stimulation in vitro and in vivo, and inhibits liver inflammation in an iNKT cell-mediated hepatitis model. Furthermore, Raptor deficiency and rapamycin treatment lead to aberrant intracellular localization and functional impairment of promyelocytic leukemia zinc-finger, a transcription factor critical for iNKT-cell development and effector programs. Our findings define an essential role of mTORC1 to direct iNKT-cell lineage development and effector function.

Authors
Shin, J; Wang, S; Deng, W; Wu, J; Gao, J; Zhong, X-P
MLA Citation
Shin, J, Wang, S, Deng, W, Wu, J, Gao, J, and Zhong, X-P. "Mechanistic target of rapamycin complex 1 is critical for invariant natural killer T-cell development and effector function." Proceedings of the National Academy of Sciences of the United States of America 111.8 (2014): E776-E783.
Source
scival
Published In
Proceedings of the National Academy of Sciences of USA
Volume
111
Issue
8
Publish Date
2014
Start Page
E776
End Page
E783
DOI
10.1073/pnas.1315435111

Critical role of the tumor suppressor tuberous sclerosis complex 1 in dendritic cell activation of CD4 T cells by promoting MHC class II expression via IRF4 and CIITA.

Dendritic cell (DC) maturation is characterized by upregulation of cell-surface MHC class II (MHC-II) and costimulatory molecules, and production of a variety of cytokines that can shape both innate and adaptive immunity. Paradoxically, transcription of the MHC-II genes, as well as its activator, CIITA, is rapidly silenced during DC maturation. The mechanisms that control CIITA/MHC-II expression and silencing have not been fully understood. We report in this article that the tumor suppressor tuberous sclerosis complex 1 (TSC1) is a critical regulator of DC function for both innate and adaptive immunity. Its deficiency in DCs results in increased mammalian target of rapamycin (mTOR) complex 1 but decreased mTORC2 signaling, altered cytokine production, impaired CIITA/MHC-II expression, and defective Ag presentation to CD4 T cells after TLR4 stimulation. We demonstrate further that IFN regulatory factor 4 can directly bind to CIITA promoters, and decreased IFN regulatory factor 4 expression is partially responsible for decreased CIITA/MHC-II expression in TSC1-deficient DCs. Moreover, we identify that CIITA/MHC-II silencing during DC maturation requires mTOR complex 1 activity. Together, our data reveal unexpected roles of TSC1/mTOR that control multifaceted functions of DCs.

Authors
Pan, H; O'Brien, TF; Wright, G; Yang, J; Shin, J; Wright, KL; Zhong, X-P
MLA Citation
Pan, H, O'Brien, TF, Wright, G, Yang, J, Shin, J, Wright, KL, and Zhong, X-P. "Critical role of the tumor suppressor tuberous sclerosis complex 1 in dendritic cell activation of CD4 T cells by promoting MHC class II expression via IRF4 and CIITA." J Immunol 191.2 (July 15, 2013): 699-707.
PMID
23776173
Source
pubmed
Published In
Journal of immunology (Baltimore, Md. : 1950)
Volume
191
Issue
2
Publish Date
2013
Start Page
699
End Page
707
DOI
10.4049/jimmunol.1201443

Signal control of iNKT development and effector lineage differentiation

Authors
Zhong, X; Wu, J; Wang, S; Shin, J
MLA Citation
Zhong, X, Wu, J, Wang, S, and Shin, J. "Signal control of iNKT development and effector lineage differentiation." May 1, 2013.
Source
wos-lite
Published In
Journal of immunology (Baltimore, Md. : 1950)
Volume
190
Publish Date
2013

Type B CpG oligodeoxynucleotides induce Th1 responses to peanut antigens: modulation of sensitization and utility in a truncated immunotherapy regimen in mice.

SCOPE: Peanut allergy stems from a Th2-biased immune response to peanut allergens leading to IgE production and allergic reactions upon ingestion. METHODS AND RESULTS: A model of peanut allergy in C3H/HeJ mice was used to assess whether type A, B, or C CpG oligodeoxynucleotide (ODN) molecules would be effective in: (i) a prophylactic approach to prevent peanut allergy when administered simultaneously with a Th2-skewing adjuvant, and (ii) a therapeutic model to allow for shortened immunotherapy. Type B ODNs were extremely effective in inhibiting anaphylaxis in the sensitization protocol as evidenced by differences in symptom scores, body temperature, and mouse mast cell protease 1 release compared to sham treatment. In the therapeutic model, co-administration of type B ODN plus peanut proteins was highly effective in reducing anaphylactic reactions in mice with established peanut allergy. The therapeutic effect was accompanied by an increase in IFN-γ and peanut-IgG2a, without a significant decrease in peanut IgE or IL-4 responses. CONCLUSION: CpG ODNs, especially type B, were highly effective in inducing Th1 responses in mice undergoing induction of peanut allergy, as well as in mice undergoing therapy for established peanut allergy. Interestingly, the IgE response was not significantly altered, suggesting that IgG antibodies may be enough to prevent peanut-induced anaphylaxis.

Authors
Kulis, M; Gorentla, B; Burks, AW; Zhong, X-P
MLA Citation
Kulis, M, Gorentla, B, Burks, AW, and Zhong, X-P. "Type B CpG oligodeoxynucleotides induce Th1 responses to peanut antigens: modulation of sensitization and utility in a truncated immunotherapy regimen in mice." Mol Nutr Food Res 57.5 (May 2013): 906-915.
PMID
23386314
Source
pubmed
Published In
Molecular Nutrition & Food Research
Volume
57
Issue
5
Publish Date
2013
Start Page
906
End Page
915
DOI
10.1002/mnfr.201200410

Mnk1 and 2 are dispensable for T cell development and activation but important for the pathogenesis of experimental autoimmune encephalomyelitis.

T cell development and activation are usually accompanied by expansion and production of numerous proteins that require active translation. The eukaryotic translation initiation factor 4E (eIF4E) binds to the 5' cap structure of mRNA and is critical for cap-dependent translational initiation. It has been hypothesized that MAPK-interacting kinase 1 and 2 (Mnk1/2) promote cap-dependent translation by phosphorylating eIF4E at serine 209 (S209). Pharmacologic studies using inhibitors have suggested that Mnk1/2 have important roles in T cells. However, genetic evidence supporting such conclusions is lacking. Moreover, the signaling pathways that regulate Mnk1/2 in T cells remain unclear. We demonstrate that TCR engagement activates Mnk1/2 in primary T cells. Such activation is dependent on Ras-Erk1/2 signaling and is inhibited by diacylglycerol kinases α and ζ. Mnk1/2 double deficiency in mice abolishes TCR-induced eIF4E S209 phosphorylation, indicating their absolute requirement for eIF4E S209 phosphorylation. However, Mnk1/2 double deficiency does not affect the development of conventional αβ T cells, regulatory T cells, or NKT cells. Furthermore, T cell activation, in vivo primary and memory CD8 T cell responses to microbial infection, and NKT cell cytokine production were not obviously altered by Mnk1/2 deficiency. Although Mnk1/2 deficiency causes decreased IL-17 and IFN-γ production by CD4 T cells following immunization of mice with myelin oligodendrocyte glycoprotein peptide in complete Freund's adjuvant, correlating with milder experimental autoimmune encephalomyelitis scores, it does not affect Th cell differentiation in vitro. Together, these data suggest that Mnk1/2 has a minimal role in T cell development and activation but may regulate non-T cell lineages to control Th1 and Th17 differentiation in vivo.

Authors
Gorentla, BK; Krishna, S; Shin, J; Inoue, M; Shinohara, ML; Grayson, JM; Fukunaga, R; Zhong, X-P
MLA Citation
Gorentla, BK, Krishna, S, Shin, J, Inoue, M, Shinohara, ML, Grayson, JM, Fukunaga, R, and Zhong, X-P. "Mnk1 and 2 are dispensable for T cell development and activation but important for the pathogenesis of experimental autoimmune encephalomyelitis." J Immunol 190.3 (February 1, 2013): 1026-1037.
PMID
23269249
Source
pubmed
Published In
Journal of immunology (Baltimore, Md. : 1950)
Volume
190
Issue
3
Publish Date
2013
Start Page
1026
End Page
1037
DOI
10.4049/jimmunol.1200026

Negative control of mast cell degranulation and the anaphylactic response by the phosphatase lipin1.

Mast cells play a critical role in the pathogenesis of allergic diseases; however, how mast cell function is regulated is still not well understood. Both phosphatidic acid (PA) and diacylglycerol (DAG) are important secondary messengers involved in mast cell activ-ation. Lipin1 is a phosphatidate phosphatase that hydrolyzes PA to produce DAG, but the role of lipin1 in mast cell function has been thus far unknown. Here we show that lipin1 is an important and selective inhibitor of mast cell degranulation. Lipin1 deficiency enhanced FcεRI-mediated β-hexosaminidase and prostaglandin D2 release from mast cells in vitro and exacerbated the passive systemic anaphylaxis reaction in vivo. Lipin1 deficiency, however, did not exert obvious effects on IL-6 or TNF-α production following FcεRI engagement. FcεRI-induced PKC and SNAP-23 phosphorylation were augmented in the lipin1-deficient mast cells. Moreover, inhibition of PKC activity reduced SNAP-23 phosphorylation and mast cell degranulation in lipin1-deficient mast cells. Together, our findings suggest that lipin1 may negatively control mast cell degranulation and the anaphylactic response through inhibiting the PKC-SNAP-23 pathway.

Authors
Shin, J; Zhang, P; Wang, S; Wu, J; Guan, Z; Zhong, X-P
MLA Citation
Shin, J, Zhang, P, Wang, S, Wu, J, Guan, Z, and Zhong, X-P. "Negative control of mast cell degranulation and the anaphylactic response by the phosphatase lipin1." Eur J Immunol 43.1 (January 2013): 240-248.
PMID
23065777
Source
pubmed
Published In
European Journal of Immunology
Volume
43
Issue
1
Publish Date
2013
Start Page
240
End Page
248
DOI
10.1002/eji.201242571

Role of diacylglycerol kinases in T cell development and function.

Diacylglycerol (DAG), a second messenger generated by phospholipase Cγ1 activity upon engagement of a T-cell receptor, triggers several signaling cascades that play important roles in T cell development and function. A family of enzymes called DAG kinases (DGKs) catalyzes the phosphorylation of DAG to phosphatidic acid, acting as a braking mechanism that terminates DAG-mediated signals. Two DGK isoforms, α and ζ, are expressed predominantly in T cells and synergistically regulate the development of both conventional αβ T cells and invariant natural killer T cells in the thymus. In mature T cells, the activity of these DGK isoforms aids in the maintenance of self-tolerance by preventing T-cell hyperactivation upon T cell receptor stimulation and by promoting T-cell anergy. In CD8 cells, reduced DGK activity is associated with enhanced primary responses against viruses and tumors. Recent work also has established an important role for DGK activity at the immune synapse and identified partners that modulate DGK function. In addition, emerging evidence points to previously unappreciated roles for DGK function in directional secretion and T-cell adhesion. This review describes the multitude of roles played by DGKs in T cell development and function and emphasizes recent advances in the field.

Authors
Krishna, S; Zhong, X
MLA Citation
Krishna, S, and Zhong, X. "Role of diacylglycerol kinases in T cell development and function." Crit Rev Immunol 33.2 (2013): 97-118. (Review)
PMID
23582058
Source
pubmed
Published In
Critical Reviews in Immunology
Volume
33
Issue
2
Publish Date
2013
Start Page
97
End Page
118

Negative control of mast cell degranulation and the anaphylactic response by the phosphatase lipin1

Mast cells play a critical role in the pathogenesis of allergic diseases; however, how mast cell function is regulated is still not well understood. Both phosphatidic acid (PA) and diacylglycerol (DAG) are important secondary messengers involved in mast cell activ-ation. Lipin1 is a phosphatidate phosphatase that hydrolyzes PA to produce DAG, but the role of lipin1 in mast cell function has been thus far unknown. Here we show that lipin1 is an important and selective inhibitor of mast cell degranulation. Lipin1 deficiency enhanced FcεRI-mediated β-hexosaminidase and prostaglandin D2 release from mast cells in vitro and exacerbated the passive systemic anaphylaxis reaction in vivo. Lipin1 deficiency, however, did not exert obvious effects on IL-6 or TNF-α production following FcεRI engagement. FcεRI-induced PKC and SNAP-23 phosphorylation were augmented in the lipin1-deficient mast cells. Moreover, inhibition of PKC activity reduced SNAP-23 phosphorylation and mast cell degranulation in lipin1-deficient mast cells. Together, our findings suggest that lipin1 may negatively control mast cell degranulation and the anaphylactic response through inhibiting the PKC-SNAP-23 pathway. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Authors
Shin, J; Zhang, P; Wang, S; Wu, J; Guan, Z; Zhong, X-P
MLA Citation
Shin, J, Zhang, P, Wang, S, Wu, J, Guan, Z, and Zhong, X-P. "Negative control of mast cell degranulation and the anaphylactic response by the phosphatase lipin1." European Journal of Immunology 43.1 (2013): 240-248.
Source
scival
Published In
European Journal of Immunology
Volume
43
Issue
1
Publish Date
2013
Start Page
240
End Page
248
DOI
10.1002/eji.201242571

Diacylglycerol kinase zeta positively controls the development of iNKT-17 cells.

Invariant natural killer T (iNKT) cells play important roles in bridging innate and adaptive immunity via rapidly producing a variety of cytokines. A small subset of iNKT cells produces IL-17 and is generated in the thymus during iNKT-cell ontogeny. The mechanisms that control the development of these IL-17-producing iNKT-17 cells (iNKT-17) are still not well defined. Diacylglycerol kinase ζ (DGKζ) belongs to a family of enzymes that catalyze the phosphorylation and conversion of diacylglycerol to phosphatidic acid, two important second messengers involved in signaling from numerous receptors. We report here that DGKζ plays an important role in iNKT-17 development. A deficiency of DGKζ in mice causes a significant reduction of iNKT-17 cells, which is correlated with decreased RORγt and IL-23 receptor expression. Interestingly, iNKT-17 defects caused by DGKζ deficiency can be corrected in chimeric mice reconstituted with mixed wild-type and DGKζ-deficient bone marrow cells. Taken together, our data identify DGKζ as an important regulator of iNKT-17 development through iNKT-cell extrinsic mechanisms.

Authors
Wu, J; Shen, S; Yang, J; Xia, Z; Zhong, X-P
MLA Citation
Wu, J, Shen, S, Yang, J, Xia, Z, and Zhong, X-P. "Diacylglycerol kinase zeta positively controls the development of iNKT-17 cells. (Published online)" PLoS One 8.9 (2013): e75202-.
PMID
24073253
Source
pubmed
Published In
PloS one
Volume
8
Issue
9
Publish Date
2013
Start Page
e75202
DOI
10.1371/journal.pone.0075202

MicroRNA-34a enhances T cell activation by targeting diacylglycerol kinase ζ.

The engagement of the T cell receptor (TCR) induces the generation of diacylglycerol (DAG), an important second messenger activating both the Ras/Erk and PKCθ/NFκB pathways. DAG kinases (DGKs) participate in the metabolism of DAG by converting it to phosphatidic acid. DGKζ has been demonstrated to be able to inhibit DAG signaling following TCR engagement. Deficiency of DGKζ increases the sensitivity of T cells to TCR stimulation, resulting in enhanced T cell activation ex vivo and in vivo. However, the mechanisms that control DGKζ expression are poorly understood. Here we demonstrate that DGKζ mRNA is a direct target of a cellular microRNA miR-34a. The DGKζ transcript is decreased, whereas the primary miR-34a is upregulated upon TCR stimulation. Ectopic miR-34a expression suppresses DGKζ protein expression through the seed match binding to both the 3' untranslated region and coding region of DGKζ mRNA, leading to increased ERK1/2 phosphorylation and surface expression of the T cell activation marker CD69 following TCR cross-linking. In contrast, overexpression of a miR-34a competitive inhibitor increases DGKζ expression and suppresses TCR-mediated T cell activation. Together, our data demonstrate that miR-34a is a negative regulator for DGKζ and may play an important role in regulating T cell activation.

Authors
Shin, J; Xie, D; Zhong, X-P
MLA Citation
Shin, J, Xie, D, and Zhong, X-P. "MicroRNA-34a enhances T cell activation by targeting diacylglycerol kinase ζ. (Published online)" PLoS One 8.10 (2013): e77983-.
PMID
24147106
Source
pubmed
Published In
PloS one
Volume
8
Issue
10
Publish Date
2013
Start Page
e77983
DOI
10.1371/journal.pone.0077983

Pepsinized cashew proteins are hypoallergenic and immunogenic and provide effective immunotherapy in mice with cashew allergy.

BACKGROUND: IgE-mediated allergic reactions to cashews and other nuts can trigger life-threatening anaphylaxis. Proactive therapies to decrease reaction severity do not exist. OBJECTIVES: We aimed to determine the efficacy of pepsin-digested cashew proteins used as immunotherapy in a murine model of cashew allergy. METHODS: Mice were sensitized to cashew and then underwent challenges with digested or native cashew allergens to assess the allergenicity of the protein preparations. Using native or pepsinized cashew proteins, mice underwent oral or intraperitoneal sensitization protocols to determine the immunogenic properties of the protein preparations. Finally, cashew-sensitized mice underwent an immunotherapy protocol with native or pepsinized cashew proteins and subsequent provocation challenges. RESULTS: Pepsinized cashew proteins elicited weaker allergic reactions than native cashew proteins but importantly retained the ability to stimulate cellular proliferation and cytokine production. Mice sensitized with pepsinized proteins reacted on challenge with native allergens, demonstrating that pepsinized allergens retain immunogenicity in vivo. Immunotherapy with pepsinized cashew allergens significantly decreased allergic symptoms and body temperature decrease relative to placebo after challenge with native and pepsinized proteins. Immunologic changes were comparable after immunotherapy with native or pepsinized allergens: T(H)2-type cytokine secretion from splenocytes was decreased, whereas specific IgG(1) and IgG(2a) levels were increased. CONCLUSIONS: Pepsinized cashew proteins are effective in treating cashew allergy in mice and appear to work through the same mechanisms as native protein immunotherapy.

Authors
Kulis, M; Macqueen, I; Li, Y; Guo, R; Zhong, X-P; Burks, AW
MLA Citation
Kulis, M, Macqueen, I, Li, Y, Guo, R, Zhong, X-P, and Burks, AW. "Pepsinized cashew proteins are hypoallergenic and immunogenic and provide effective immunotherapy in mice with cashew allergy." J Allergy Clin Immunol 130.3 (September 2012): 716-723.
PMID
22795369
Source
pubmed
Published In
Journal of Allergy and Clinical Immunology
Volume
130
Issue
3
Publish Date
2012
Start Page
716
End Page
723
DOI
10.1016/j.jaci.2012.05.044

Differential requirement of RasGRP1 for γδ T cell development and activation.

γδ T (γδT) cells belong to a distinct T cell lineage that performs immune functions different from αβ T (αβT) cells. Previous studies established that Erk1/2 MAPKs are critical for positive selection of αβT cells. Additional evidence suggests that increased Erk1/2 activity promotes γδT cell generation. RasGRP1, a guanine nucleotide-releasing factor for Ras, plays an important role in positive selection of αβT cells by activating the Ras-Erk1/2 pathway. In this article, we demonstrate that RasGRP1 is critical for TCR-induced Erk1/2 activation in γδT cells, but it exerts different roles for γδT cell generation and activation. Deficiency of RasGRP1 does not obviously affect γδT cell numbers in the thymus, but it leads to increased γδT cells, particularly CD4(-)CD8(+) γδT cells, in the peripheral lymphoid organs. The virtually unhindered γδT cell development in the RasGRP1(-/-) thymus proved to be cell intrinsic, whereas the increase in CD8(+) γδT cells is caused by non-cell-intrinsic mechanisms. Our data provide genetic evidence that decreased Erk1/2 activation in the absence of RasGRP1 is compatible with γδT cell generation. Although RasGRP1 is dispensable for γδT cell generation, RasGRP1-deficient γδT cells are defective in proliferation following TCR stimulation. Additionally, RasGRP1-deficient γδT cells are impaired to produce IL-17 but not IFNγ. Together, these observations revealed that RasGRP1 plays differential roles for γδ and αβ T cell development but is critical for γδT cell proliferation and production of IL-17.

Authors
Chen, Y; Ci, X; Gorentla, B; Sullivan, SA; Stone, JC; Zhang, W; Pereira, P; Lu, J; Zhong, X-P
MLA Citation
Chen, Y, Ci, X, Gorentla, B, Sullivan, SA, Stone, JC, Zhang, W, Pereira, P, Lu, J, and Zhong, X-P. "Differential requirement of RasGRP1 for γδ T cell development and activation." J Immunol 189.1 (July 1, 2012): 61-71.
PMID
22623331
Source
pubmed
Published In
Journal of immunology (Baltimore, Md. : 1950)
Volume
189
Issue
1
Publish Date
2012
Start Page
61
End Page
71
DOI
10.4049/jimmunol.1103272

CD45-deficient severe combined immunodeficiency caused by uniparental disomy.

Analysis of the molecular etiologies of SCID has led to important insights into the control of immune cell development. Most cases of SCID result from either X-linked or autosomal recessive inheritance of mutations in a known causative gene. However, in some cases, the molecular etiology remains unclear. To identify the cause of SCID in a patient known to lack the protein-tyrosine phosphatase CD45, we used SNP arrays and whole-exome sequencing. The patient's mother was heterozygous for an inactivating mutation in CD45 but the paternal alleles exhibited no detectable mutations. The patient exhibited a single CD45 mutation identical to the maternal allele. Patient SNP array analysis revealed no change in copy number but loss of heterozygosity for the entire length of chromosome 1 (Chr1), indicating that disease was caused by uniparental disomy (UPD) with isodisomy of the entire maternal Chr1 bearing the mutant CD45 allele. Nonlymphoid blood cells and other mesoderm- and ectoderm-derived tissues retained UPD of the entire maternal Chr1 in this patient, who had undergone successful bone marrow transplantation. Exome sequencing revealed mutations in seven additional genes bearing nonsynonymous SNPs predicted to have deleterious effects. These findings are unique in representing a reported case of SCID caused by UPD and suggest UPD should be considered in SCID and other recessive disorders, especially when the patient appears homozygous for an abnormal gene found in only one parent. Evaluation for alterations in other genes affected by UPD should also be considered in such cases.

Authors
Roberts, JL; Buckley, RH; Luo, B; Pei, J; Lapidus, A; Peri, S; Wei, Q; Shin, J; Parrott, RE; Dunbrack, RL; Testa, JR; Zhong, X-P; Wiest, DL
MLA Citation
Roberts, JL, Buckley, RH, Luo, B, Pei, J, Lapidus, A, Peri, S, Wei, Q, Shin, J, Parrott, RE, Dunbrack, RL, Testa, JR, Zhong, X-P, and Wiest, DL. "CD45-deficient severe combined immunodeficiency caused by uniparental disomy." Proc Natl Acad Sci U S A 109.26 (June 26, 2012): 10456-10461.
PMID
22689986
Source
pubmed
Published In
Proceedings of the National Academy of Sciences of USA
Volume
109
Issue
26
Publish Date
2012
Start Page
10456
End Page
10461
DOI
10.1073/pnas.1202249109

The role of tuberous sclerosis complex 1 in regulating innate immunity.

The mechanisms that control TLR-induced responses, including endotoxin tolerance, have been not well understood. The tuberous sclerosis complex 1 (TSC1) is a tumor suppressor that inhibits the mammalian target of rapamycin (mTOR). We show in this study that deficiency of TSC1 results in enhanced activation of not only mTOR complex 1 (mTORC1), but also JNK1/2, following LPS stimulation in macrophages. TSC1-deficient macrophages produce elevated proinflammatory cytokines and NO in response to multiple TLR ligands. Such enhanced TLR-induced responses can be inhibited by reducing mTORC1 and JNK1/2 activities with chemical inhibitors or small hairpin RNA, suggesting that TSC1 negatively controls TLR responses through both mTORC1 and JNK1/2. The impact of TSC1 deficiency appeared not limited to TLRs, as NOD- and RIG-I/MDA-5-induced innate responses were also altered in TSC1-deficient macrophages. Furthermore, TSC1 deficiency appears to cause impaired induction of endotoxin tolerance in vitro and in vivo, which is correlated with increased JNK1/2 activation and can be reversed by JNK1/2 inhibition. Our results reveal a critical role of TSC1 in regulating innate immunity by negative control of mTORC1 and JNK1/2 activation.

Authors
Pan, H; O'Brien, TF; Zhang, P; Zhong, X-P
MLA Citation
Pan, H, O'Brien, TF, Zhang, P, and Zhong, X-P. "The role of tuberous sclerosis complex 1 in regulating innate immunity." J Immunol 188.8 (April 15, 2012): 3658-3666.
PMID
22412198
Source
pubmed
Published In
Journal of immunology (Baltimore, Md. : 1950)
Volume
188
Issue
8
Publish Date
2012
Start Page
3658
End Page
3666
DOI
10.4049/jimmunol.1102187

Murine regulatory T cells contain hyperproliferative and death-prone subsets with differential ICOS expression.

Regulatory T cells (Treg) are crucial for self-tolerance. It has been an enigma that Treg exhibit an anergic phenotype reflected by hypoproliferation in vitro after TCR stimulation but undergo vigorous proliferation in vivo. We report in this study that murine Treg are prone to death but hyperproliferative in vitro and in vivo, which is different from conventional CD4(+)Foxp3(-) T cells (Tcon). During in vitro culture, most Treg die with or without TCR stimulation, correlated with constitutive activation of the intrinsic death pathway. However, a small portion of the Treg population is more sensitive to TCR stimulation, particularly weak stimulation, proliferates more vigorously than CD4(+) Tcon, and is resistant to activation-induced cell death. Treg proliferation is enhanced by IL-2 but is less dependent on CD28-mediated costimulation than that of Tcon. We demonstrate further that the surviving and proliferative Treg are ICOS(+) whereas the death-prone Treg are ICOS(-). Moreover, ICOS(+) Treg contain much stronger suppressive activity than that of ICOS(-) Treg. Our data indicate that massive death contributes to the anergic phenotype of Treg in vitro and suggest modulation of Treg survival as a therapeutic strategy for treatment of autoimmune diseases and cancer.

Authors
Chen, Y; Shen, S; Gorentla, BK; Gao, J; Zhong, X-P
MLA Citation
Chen, Y, Shen, S, Gorentla, BK, Gao, J, and Zhong, X-P. "Murine regulatory T cells contain hyperproliferative and death-prone subsets with differential ICOS expression." J Immunol 188.4 (February 15, 2012): 1698-1707.
PMID
22231701
Source
pubmed
Published In
Journal of immunology (Baltimore, Md. : 1950)
Volume
188
Issue
4
Publish Date
2012
Start Page
1698
End Page
1707
DOI
10.4049/jimmunol.1102448

An expanded role of the tumor suppressor TSC1 in T cell tolerance

Authors
Zhong, X-P
MLA Citation
Zhong, X-P. "An expanded role of the tumor suppressor TSC1 in T cell tolerance." Cell Cycle 11.21 (2012): 3909-3910.
PMID
23032259
Source
scival
Published In
Cell Cycle
Volume
11
Issue
21
Publish Date
2012
Start Page
3909
End Page
3910
DOI
10.4161/cc.22235

FoxO-dependent regulation of diacylglycerol kinase α gene expression

Diacylglycerol kinase α (DGKα) regulates diacylglycerol levels, catalyzing its conversion into phosphatidic acid. The α isoform is central to immune response regulation; it downmodulates Ras-dependent pathways and is necessary for establishment of the unresponsive state termed anergy. DGKα functions are regulated in part at the transcriptional level although the mechanisms involved remain poorly understood. Here, we analyzed the 5' end structure of the mouse DGKα gene and detected three binding sites for forkhead box O (FoxO) transcription factors, whose function was confirmed using luciferase reporter constructs. FoxO1 and FoxO3 bound to the 5= regulatory region of DGKα in quiescent T cells, as well as after interleukin-2 (IL-2) withdrawal in activated T cells. FoxO binding to this region was lost after complete T cell activation or IL-2 addition, events that correlated with FoxO phosphorylation and a sustained decrease in DGKα gene expression. These data strongly support a role for FoxO proteins in promoting high DGKα levels and indicate a mechanism by which DGKα function is downregulated during productive T cell responses. Our study establishes a basis for a causal relationship between DGKα downregulation, IL-2, and anergy avoidance. © 2012, American Society for Microbiology.

Authors
Martínez-Moreno, M; García-Liévana, J; Soutar, D; Torres-Ayuso, P; Andrada, E; Zhong, X-P; Koretzky, GA; Mérida, I; Ávila-Flores, A
MLA Citation
Martínez-Moreno, M, García-Liévana, J, Soutar, D, Torres-Ayuso, P, Andrada, E, Zhong, X-P, Koretzky, GA, Mérida, I, and Ávila-Flores, A. "FoxO-dependent regulation of diacylglycerol kinase α gene expression." Molecular and Cellular Biology 32.20 (2012): 4168-4180.
PMID
22890845
Source
scival
Published In
Molecular and Cellular Biology
Volume
32
Issue
20
Publish Date
2012
Start Page
4168
End Page
4180
DOI
10.1128/MCB.00654-12

Tumor suppressor TSC1 is critical for T-cell anergy

T-cell anergy is a state of T cells that is hyporesponsive to stimulation via the T-cell receptor and costimulatory molecules and is thought to be important for self-tolerance. How T-cell anergy is regulated is still poorly understood. We report here that tuberous sclerosis (TSC)1 is critical for T-cell anergy. Deficiency of TSC1 resulted in enhanced T-cell proliferation and cytokine production in the absence of cluster of differentiation (CD)28-mediated costimulation, accompanied by enhanced T-cell metabolism. Resistance of TSC1-deficient T cells to anergy is correlated with increased signaling through the mammalian target of rapamycin complex (mTORC)1 and can be reverted by treatment of these cellswithmTORC1 inhibitor rapamycin. Expression of the inducible costimulator (ICOS) is increased in TSC1-deficient T cells, which can be inhibited by rapamycin. Simultaneous blockade of both CD28 and ICOS costimulation partially restored sensitivity of TSC1-deficient T cells to anergy induction. Together, our data indicate that TSC1 is crucial for T-cell anergy by inhibiting mTORC1 signaling through both ICOS-dependent and -independent mechanisms.

Authors
Xie, D-L; Wu, J; Lou, Y-L; Zhong, X-P
MLA Citation
Xie, D-L, Wu, J, Lou, Y-L, and Zhong, X-P. "Tumor suppressor TSC1 is critical for T-cell anergy." Proceedings of the National Academy of Sciences of the United States of America 109.35 (2012): 14152-14157.
PMID
22891340
Source
scival
Published In
Proceedings of the National Academy of Sciences of USA
Volume
109
Issue
35
Publish Date
2012
Start Page
14152
End Page
14157
DOI
10.1073/pnas.1119744109

Chronic activation of the kinase IKKβ impairs T cell function and survival

Activation of the transcription factor NF-κB is critical for cytokine production and T cell survival after TCR engagement. The effects of persistent NF-κB activity on T cell function and survival are poorly understood. In this study, using a murine model that expresses a constitutively active form of inhibitor of NF-κB kinase β (caIKKβ) in a T cell-specific manner, we demonstrate that chronic inhibitor of NF-κB kinase β signaling promotes T cell apoptosis, attenuates responsiveness to TCR-mediated stimulation in vitro, and impairs T cell responses to bacterial infection in vivo. caIKKβ T cells showed increased Fas ligand expression and caspase-8 activation, and blocking Fas/Fas ligand interactions enhanced cell survival. T cell unresponsiveness was associated with defects in TCR proximal signaling and elevated levels of B lymphocyte-induced maturation protein 1, a transcriptional repressor that promotes T cell exhaustion. caIKKβ T cells also showed a defect in IL-2 production, and addition of exogenous IL-2 enhanced their survival and proliferation. Conditional deletion of B lymphocyte-induced maturation protein 1 partially rescued the sensitivity of caIKKβ T cells to TCR triggering. Furthermore, adoptively transferred caIKKβ T cells showed diminished expansion and increased contraction in response to infection with Listeria monocytogenes expressing a cognate Ag. Despite their functional defects, caIKKβ T cells readily produced proinflammatory cytokines, and mice developed autoimmunity. In contrast to NF-κB's critical role in T cell activation and survival, our study demonstrates that persistent IKK-NF-κB signaling is sufficient to impair both T cell function and survival. Copyright © 2012 by The American Association of Immunologists, Inc.

Authors
Krishna, S; Xie, D; Gorentla, B; Shin, J; Gao, J; Zhong, X-P
MLA Citation
Krishna, S, Xie, D, Gorentla, B, Shin, J, Gao, J, and Zhong, X-P. "Chronic activation of the kinase IKKβ impairs T cell function and survival." Journal of Immunology 189.3 (2012): 1209-1219.
PMID
22753932
Source
scival
Published In
Journal of immunology (Baltimore, Md. : 1950)
Volume
189
Issue
3
Publish Date
2012
Start Page
1209
End Page
1219
DOI
10.4049/jimmunol.1102429

The role and regulation of mTOR in T-lymphocyte function

The conversion of naïve T cells into effector T cells is initiated by stimulation through the T-cell receptor (TCR). Upon activation, T cells undergo significant morphological and functional changes, putting new metabolic demands on the cell. Past research has identified the mammalian target of rapamycin (mTOR) as a critical regulator of cell metabolism, and the development of new genetic models has begun to reveal an important role for this pathway in the homeostasis and function of T lymphocytes. In this review, we focus on the most recent findings that demonstrate the ability of mTOR to regulate T-cell activation, CD8 + memory cell formation and function, and helper T lineage differentiation. Furthermore, we highlight the importance of tight control of mTOR signaling by tuberous sclerosis complex 1 for T-cell homeostasis, and the regulation of mTOR signaling by diacylglycerol kinases and the RasGRP1-Ras-Erk1/2 pathway in the context of TCR signaling. © L. Hirszfeld Institute of Immunology and Experimental Therapy, Wroclaw, Poland 2012.

Authors
O'Brien, TF; Zhong, X-P
MLA Citation
O'Brien, TF, and Zhong, X-P. "The role and regulation of mTOR in T-lymphocyte function." Archivum Immunologiae et Therapiae Experimentalis 60.3 (2012): 173-181.
PMID
22484804
Source
scival
Published In
Archivum Immunologiae et Therapiae Experimentalis
Volume
60
Issue
3
Publish Date
2012
Start Page
173
End Page
181
DOI
10.1007/s00005-012-0171-4

Regulation of mast cell survival and function by tuberous sclerosis complex 1

Mast cells play critical roles in allergic disorders and asthma. The importance of tuberous sclerosis complex 1/2-mammalian target of rapamycin (TSC1/2-mTOR) signaling in mast cells is unknown. Here, we report that TSC1 is a critical regulator for mTOR signaling in mast cells downstream of FcεRI and c-Kit, and differentially controls mast cell degranulation and cytokine production. TSC1-deficiency results in impaired mast cell degranulation, but enhanced cytokine production in vitro and in vivo after FcεRI engagement. Furthermore, TSC1 is critical for mast cell survival through multiple pathways of apoptosis including the downregulation of p53, miR-34a, reactive oxygen species, and the up-regulation of Bcl-2. Together, these findings reveal that TSC1 is a critical regulator of mast cell activation and survival, suggesting the manipulation of the TSC1/2-mTOR pathway as a therapeutic strategy for mast cell-mediated diseases. © 2012 by The American Society of Hematology.

Authors
Shin, J; Pan, H; Zhong, X-P
MLA Citation
Shin, J, Pan, H, and Zhong, X-P. "Regulation of mast cell survival and function by tuberous sclerosis complex 1." Blood 119.14 (2012): 3306-3314.
PMID
22362037
Source
scival
Published In
Blood
Volume
119
Issue
14
Publish Date
2012
Start Page
3306
End Page
3314
DOI
10.1182/blood-2011-05-353342

Differential regulation of primary and memory CD8 T cell immune responses by diacylglycerol kinases

The manipulation of signals downstream of the TCR can have profound consequences for T cell development, function, and homeostasis. Diacylglycerol (DAG) produced after TCR stimulation functions as a secondary messenger and mediates the signaling to Ras-MEK-Erk and NF-κB pathways in T cells. DAG kinases (DGKs) convert DAG into phosphatidic acid, resulting in termination of DAG signaling. In this study, we demonstrate that DAG metabolism by DGKs can serve a crucial function in viral clearance upon lymphocytic choriomeningitis virus infection. Ag-specific CD8 + T cells from DGKα -/- and DGKζ -/- mice show enhanced expansion and increased cytokine production after lymphocytic choriomeningitis virus infection, yet DGK-deficient memory CD8 + T cells exhibit impaired expansion after rechallenge. Thus, DGK activity plays opposing roles in the expansion of CD8 + T cells during the primary and memory phases of the immune response, whereas consistently inhibiting antiviral cytokine production. Copyright © 2012 by The American Association of Immunologists, Inc.

Authors
Shin, J; O'Brien, TF; Grayson, JM; Zhong, X-P
MLA Citation
Shin, J, O'Brien, TF, Grayson, JM, and Zhong, X-P. "Differential regulation of primary and memory CD8 T cell immune responses by diacylglycerol kinases." Journal of Immunology 188.5 (2012): 2111-2117.
PMID
22271650
Source
scival
Published In
Journal of immunology (Baltimore, Md. : 1950)
Volume
188
Issue
5
Publish Date
2012
Start Page
2111
End Page
2117
DOI
10.4049/jimmunol.1102265

Critical roles of RasGRP1 for invariant NKT cell development.

The invariant NKT (iNKT) cell lineage contains CD4(+) and CD4(-) subsets. The mechanisms that control such subset differentiation and iNKT cell maturation in general have not been fully understood. RasGRP1, a guanine nucleotide exchange factor for TCR-induced activation of the Ras-ERK1/2 pathway, is critical for conventional αβ T cell development but dispensable for generating regulatory T cells. Its role in iNKT cells has been unknown. In this study, we report severe decreases of iNKT cells in RasGRP1(-/-) mice through cell intrinsic mechanisms. In the remaining iNKT cells in RasGRP1(-/-) mice, there is a selective absence of the CD4(+) subset. Furthermore, RasGRP1(-/-) iNKT cells are defective in TCR-induced proliferation in vitro. These observations establish that RasGRP1 is not only important for early iNKT cell development but also for the generation/maintenance of the CD4(+) iNKT cells. Our data provide genetic evidence that the CD4(+) and CD4(-) iNKT cells are distinct sublineages with differential signaling requirements for their development.

Authors
Shen, S; Chen, Y; Gorentla, BK; Lu, J; Stone, JC; Zhong, X-P
MLA Citation
Shen, S, Chen, Y, Gorentla, BK, Lu, J, Stone, JC, and Zhong, X-P. "Critical roles of RasGRP1 for invariant NKT cell development." J Immunol 187.9 (November 1, 2011): 4467-4473.
PMID
21957144
Source
pubmed
Published In
Journal of immunology (Baltimore, Md. : 1950)
Volume
187
Issue
9
Publish Date
2011
Start Page
4467
End Page
4473
DOI
10.4049/jimmunol.1003798

Receptor signaling in immune cell development and function.

Immune cell development and function must be tightly regulated through cell surface receptors to ensure proper responses to pathogen and tolerance to self. In T cells, the signal from the T-cell receptor is essential for T-cell maturation, homeostasis, and activation. In mast cells, the high-affinity receptor for IgE transduces signal that promotes mast cell survival and induces mast cell activation. In dendritic cells and macrophages, the toll-like receptors recognize microbial pathogens and play critical roles for both innate and adaptive immunity against pathogens. Our research explores how signaling from these receptors is transduced and regulated to better understand these immune cells. Our recent studies have revealed diacylglycerol kinases and TSC1/2-mTOR as critical signaling molecules/regulators in T cells, mast cells, dendritic cells, and macrophages.

Authors
Zhong, X-P; Shin, J; Gorentla, BK; O'Brien, T; Srivatsan, S; Xu, L; Chen, Y; Xie, D; Pan, H
MLA Citation
Zhong, X-P, Shin, J, Gorentla, BK, O'Brien, T, Srivatsan, S, Xu, L, Chen, Y, Xie, D, and Pan, H. "Receptor signaling in immune cell development and function." Immunol Res 49.1-3 (April 2011): 109-123.
PMID
21128010
Source
pubmed
Published In
Immunologic Research
Volume
49
Issue
1-3
Publish Date
2011
Start Page
109
End Page
123
DOI
10.1007/s12026-010-8175-9

Regulation of T-cell survival and mitochondrial homeostasis by TSC1

The mammalian target of rapamycin (mTOR) is a key regulator of cell growth and metabolism. It associates with multiple proteins and forms two distinct signaling complexes, mTORC1 and mTORC2. Accumulating evidence has revealed critical roles for intact mTOR signaling during T-cell activation and responses to microbial infection. However, the importance of mTOR regulation in T cells has yet to be explored. The TSC1/TSC2 complex has been shown to inhibit mTORC1 signaling in cell line models. We show here that deletion of TSC1 in the murine T-cell lineage results in a dramatic reduction of the peripheral T-cell pool, correlating with increased cell death. While mTORC1 is constitutively activated, mTORC2 signaling, reflected by Akt phosphorylation and activity, is decreased in TSC1-deficient T cells. Furthermore, TSC1-deficient T cells contain elevated reactive oxygen species (ROS) and exhibit decreased mitochondrial content and membrane potential, which is correlated with the activation of the intrinsic death pathway. Overall, our results demonstrate that TSC1 differentially regulates mTORC1 and mTORC2 activity, promotes T-cell survival, and is critical for normal mitochondrial homeostasis in T cells. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Authors
O'Brien, TF; Gorentla, BK; Xie, D; Srivatsan, S; Mcleod, IX; He, Y-W; Zhong, X-P
MLA Citation
O'Brien, TF, Gorentla, BK, Xie, D, Srivatsan, S, Mcleod, IX, He, Y-W, and Zhong, X-P. "Regulation of T-cell survival and mitochondrial homeostasis by TSC1." European Journal of Immunology 41.11 (2011): 3361-3370.
PMID
21805467
Source
scival
Published In
European Journal of Immunology
Volume
41
Issue
11
Publish Date
2011
Start Page
3361
End Page
3370
DOI
10.1002/eji.201141411

HIFU as a neoadjuvant therapy in cancer treatment

To broaden the application spectrum of HIFU in cancer therapy, we performed a pilot experiment to evaluate the potential of using HIFU as a neoadjuvant therapy prior to surgery. Mice bearing wild-type B16F10 melanoma inoculated subcutaneously were either untreated (control) or treated by HIFU, CPA-7 or HIFU + CPA-7 before surgical resection of the primary tumor two days after HIFU treatment. The animals were then followed for four weeks or up to the humane endpoint to determine local recurrence, distant metastasis, and survival rate. The results demonstrate that animals treated by HIFU + CPA-7 (which is a small molecule that suppresses STAT3 activity) had a significantly lower recurrence rate, and slower growth of the recurrent tumor, with concomitantly higher survival rate, followed by those treated with CPA-7 and HIFU, respectively. Immunological assays revealed that CPA-7 treatment could significantly lower STAT3, and subsequently, Treg activities. In particular, the combination of HIFU and CPA-7 can induce a much stronger anti-tumor immune response than HIFU or surgery alone, as assessed by CTL and IFN-γ secretion. Overall, our results suggest that HIFU in combination with immunotherapy strategies has the potential to be used as a neoadjuvant therapy to prime the host with a strong anti-tumor immune response before surgical resection of the primary tumor. This multimodality, combinational therapy has the potential to greatly broaden the range of HIFU applications in cancer therapy with lower tumor recurrence and improved survival rate. © 2011 American Institute of Physics.

Authors
Zhong, P; Xing, F; Huang, X; Zhu, H; Lo, HW; Zhong, X; Pruitt, S; Robertson, C
MLA Citation
Zhong, P, Xing, F, Huang, X, Zhu, H, Lo, HW, Zhong, X, Pruitt, S, and Robertson, C. "HIFU as a neoadjuvant therapy in cancer treatment." AIP Conference Proceedings 1359 (2011): 289-294.
Source
scival
Published In
AIP Conference Proceedings
Volume
1359
Publish Date
2011
Start Page
289
End Page
294
DOI
10.1063/1.3607920

Peanut allergen Ara h 2-specific T cells are activated via Ras-Erk MAP kinase pathway signalling and identified by CD154 expression

Background. Peanut allergy is driven by peanut-specific Th2 cells. Ara h 2, a peanut 2S albumin, is one of the major peanut allergens. Methods. An Ara h 2-specific T cell line was generated from peanut sensitised C3H/HeJ mice and used to analyse allergen-induced cytokine secretion and activation of signalling molecules. Results. Peanut stimulated splenocytes from peanut sensitised mice had strong proliferation responses and highly elevated IL-4 secretion. The Ara h 2-specific T cells generated from sensitised mice were mainly CD4+ T helper cells with a Th2 cytokine profile. The expression of CD154 on the surface of these T cell clones was detected following Ara h 2 stimulation. Ara h 2 stimulation induced phosphorylation of ZAP-70 and Erk1/2 in the T cells. Conclusions. CD154 is a useful marker for identifying activated, allergen-specific T cells. The Ras-Erk mitogen-activated protein kinase pathway is involved in the activation of Ara h 2-specific Th2 cells. © 2011 Copyright Taylor and Francis Group, LLC.

Authors
Li, Y; Kulis, M; Pons, L; Zhong, X-P; Burks, AW
MLA Citation
Li, Y, Kulis, M, Pons, L, Zhong, X-P, and Burks, AW. "Peanut allergen Ara h 2-specific T cells are activated via Ras-Erk MAP kinase pathway signalling and identified by CD154 expression." Food and Agricultural Immunology 22.4 (2011): 335-344.
Source
scival
Published In
Food and Agricultural Immunology
Volume
22
Issue
4
Publish Date
2011
Start Page
335
End Page
344
DOI
10.1080/09540105.2011.579591

SAP-mediated inhibition of diacylglycerol kinase α regulates TCR-induced diacylglycerol signaling

Diacylglycerol kinases (DGKs) metabolize diacylglycerol to phosphatidic acid. In T lymphocytes, DGKα acts as a negative regulator of TCR signaling by decreasing diacylglycerol levels and inducing anergy. In this study, we show that upon costimulation of the TCR with CD28 or signaling lymphocyte activation molecule (SLAM), DGKα, but not DGKζ, exits from the nucleus and undergoes rapid negative regulation of its enzymatic activity. Inhibition of DGKα is dependent on the expression of SAP, an adaptor protein mutated in X-linked lymphoproliferative disease, which is essential for SLAM-mediated signaling and contributes to TCR/CD28-induced signaling and T cell activation. Accordingly, overexpression of SAP is sufficient to inhibit DGKα, whereas SAP mutants unable to bind either phospho-tyrosine residues or SH3 domain are ineffective. Moreover, phospholipase C activity and calcium, but not Src-family tyrosine kinases, are also required for negative regulation of DGKα. Finally, inhibition of DGKα in SAP-deficient cells partially rescues defective TCR/CD28 signaling, including Ras and ERK1/2 activation, protein kinase Cθ membrane recruitment, induction of NF-AT transcriptional activity, and IL-2 production. Thus SAP-mediated inhibition of DGKα sustains diacylglycerol signaling, thereby regulating T cell activation, and it may represent a novel pharmacological strategy for X-linked lymphoproliferative disease treatment. Copyright©2011 by The American Association of Immunologists, Inc.

Authors
Baldanzi, G; Pighini, A; Bettio, V; Rainero, E; Traini, S; Chianale, F; Porporato, PE; Filigheddu, N; Mesturini, R; Song, S; Schweighoffer, T; Patrussi, L; Baldari, CT; Zhong, X-P; Blitterswijk, WJV; Sinigaglia, F; Nichols, KE; Rubio, I; Parolini, O; Graziani, A
MLA Citation
Baldanzi, G, Pighini, A, Bettio, V, Rainero, E, Traini, S, Chianale, F, Porporato, PE, Filigheddu, N, Mesturini, R, Song, S, Schweighoffer, T, Patrussi, L, Baldari, CT, Zhong, X-P, Blitterswijk, WJV, Sinigaglia, F, Nichols, KE, Rubio, I, Parolini, O, and Graziani, A. "SAP-mediated inhibition of diacylglycerol kinase α regulates TCR-induced diacylglycerol signaling." Journal of Immunology 187.11 (2011): 5941-5951.
PMID
22048771
Source
scival
Published In
Journal of immunology (Baltimore, Md. : 1950)
Volume
187
Issue
11
Publish Date
2011
Start Page
5941
End Page
5951
DOI
10.4049/jimmunol.1002476

Tight regulation of diacylglycerol-mediated signaling is critical for proper invariant NKT cell development

Type I NKT cells, or invariant NKT (iNKT) cells, express a semi-invariant TCR characterized by its unique Vα14-Jα18 usage (iVα14TCR). Upon interaction with glycolipid/CD1d complexes, the iVα14TCRs transduce signals that are essential for iNKT selection and maturation. However, it remains unclear how these signals are regulated and how important such regulations are during iNKT development. Diacylglycerol (DAG) is an essential second messenger downstream of the TCR that activates the protein kinase Cθ-IκB kinase (IKK)α/β-NF-κB pathway, known to be crucial for iNKT development, as well as the RasGRP1-Ras-Erk1/2 pathway in T cells. DAG kinases play an important role in controlling intracellular DAG concentration and thereby negatively regulate DAG signaling. In this article, we report that simultaneous absence of DAG kinase α and ζ causes severe defects in iNKT development, coincident with enhanced IKK-NF-κB and Ras-Erk1/2 activation. Moreover, constitutive IKKβ and Ras activities also result in iNKT developmental defects. Thus, DAG-mediated signaling is not only essential but also needs to be tightly regulated for proper iNKT cell development. Copyright © 2011 by The American Association of Immunologists, Inc.

Authors
Shen, S; Wu, J; Srivatsan, S; Gorentla, BK; Shin, J; Xu, L; Zhong, X-P
MLA Citation
Shen, S, Wu, J, Srivatsan, S, Gorentla, BK, Shin, J, Xu, L, and Zhong, X-P. "Tight regulation of diacylglycerol-mediated signaling is critical for proper invariant NKT cell development." Journal of Immunology 187.5 (2011): 2122-2129.
PMID
21775687
Source
scival
Published In
Journal of immunology (Baltimore, Md. : 1950)
Volume
187
Issue
5
Publish Date
2011
Start Page
2122
End Page
2129
DOI
10.4049/jimmunol.1100495

Diacylglycerol kinase ζ deficiency in a non-CD4+ T-cell compartment leads to increased peanut hypersensitivity

Authors
Kulis, M; Wan, C-K; Gorentla, BK; Burks, AW; Zhong, X-P
MLA Citation
Kulis, M, Wan, C-K, Gorentla, BK, Burks, AW, and Zhong, X-P. "Diacylglycerol kinase ζ deficiency in a non-CD4+ T-cell compartment leads to increased peanut hypersensitivity." Journal of Allergy and Clinical Immunology 128.1 (2011): 212-214.
PMID
21439625
Source
scival
Published In
Journal of Allergy and Clinical Immunology
Volume
128
Issue
1
Publish Date
2011
Start Page
212
End Page
214
DOI
10.1016/j.jaci.2011.02.035

Negative regulation of mTOR activation by diacylglycerol kinases

The engagement of TCR induces T-cell activation, which initiates multiple characteristic changes such as increase in cell size, cell division, and the production of cytokines and other effector molecules. The mammalian target of rapamycin (mTOR) regulates protein synthesis, transcription, cell survival, and autophagy. Critical roles of mTOR in T-cell activation and effector/memory differentiation have been revealed using chemical inhibitors or by genetic ablation of mTOR in T cells. However, the connection between mTOR signaling and other signaling cascades downstream of TCR is unclear. We demonstrate that diacylglycerol (DAG) and TCR engagement activate signaling in both mTOR complexes 1 and 2 through the activation of the Ras-mitogen-activated protein kinase/extracellular signal-regulated kinase 1/2 (Mek1/2)-extracellular signal-regulated kinase 1/2 (Erk1/2)-activator protein 1 (AP-1), known collectively as the Ras-Mek1/2-Erk1/2-AP-1 pathway. Deficiency of RasGRP1 or inhibition of Mek1/2 activity drastically decreases TCR-induced mTOR activation, whereas constitutively active Ras or Mek1 promotes mTOR activation. Although constitutively active Akt promotes TCR-induced mTOR activation, such activation is attenuated by Mek1/2 inhibition. We demonstrated further that DAG kinases (DGKs) α and ζ, which terminate DAG-mediated signaling, synergistically inhibit TCR-induced mTOR activation by inhibiting the Ras-Mek1/2-Erk/12 pathway. These observations provide novel insights into the regulation of mTOR activation. © 2011 by The American Society of Hematology.

Authors
Gorentla, BK; Wan, C-K; Zhong, X-P
MLA Citation
Gorentla, BK, Wan, C-K, and Zhong, X-P. "Negative regulation of mTOR activation by diacylglycerol kinases." Blood 117.15 (2011): 4022-4031.
PMID
21310925
Source
scival
Published In
Blood
Volume
117
Issue
15
Publish Date
2011
Start Page
4022
End Page
4031
DOI
10.1182/blood-2010-08-300731

Clinical efficacy and immune regulation with peanut oral immunotherapy.

BACKGROUND: Oral immunotherapy (OIT) has been thought to induce clinical desensitization to allergenic foods, but trials coupling the clinical response and immunologic effects of peanut OIT have not been reported. OBJECTIVE: The study objective was to investigate the clinical efficacy and immunologic changes associated with OIT. METHODS: Children with peanut allergy underwent an OIT protocol including initial day escalation, buildup, and maintenance phases, and then oral food challenge. Clinical response and immunologic changes were evaluated. RESULTS: Of 29 subjects who completed the protocol, 27 ingested 3.9 g peanut protein during food challenge. Most symptoms noted during OIT resolved spontaneously or with antihistamines. By 6 months, titrated skin prick tests and activation of basophils significantly declined. Peanut-specific IgE decreased by 12 to 18 months, whereas IgG(4) increased significantly. Serum factors inhibited IgE-peanut complex formation in an IgE-facilitated allergen binding assay. Secretion of IL-10, IL-5, IFN-gamma, and TNF-alpha from PBMCs increased over a period of 6 to 12 months. Peanut-specific forkhead box protein 3 T cells increased until 12 months and decreased thereafter. In addition, T-cell microarrays showed downregulation of genes in apoptotic pathways. CONCLUSION: Oral immunotherapy induces clinical desensitization to peanut, with significant longer-term humoral and cellular changes. Microarray data suggest a novel role for apoptosis in OIT.

Authors
Jones, SM; Pons, L; Roberts, JL; Scurlock, AM; Perry, TT; Kulis, M; Shreffler, WG; Steele, P; Henry, KA; Adair, M; Francis, JM; Durham, S; Vickery, BP; Zhong, X; Burks, AW
MLA Citation
Jones, SM, Pons, L, Roberts, JL, Scurlock, AM, Perry, TT, Kulis, M, Shreffler, WG, Steele, P, Henry, KA, Adair, M, Francis, JM, Durham, S, Vickery, BP, Zhong, X, and Burks, AW. "Clinical efficacy and immune regulation with peanut oral immunotherapy." J Allergy Clin Immunol 124.2 (August 2009): 292-300.97.
PMID
19577283
Source
pubmed
Published In
Journal of Allergy and Clinical Immunology
Volume
124
Issue
2
Publish Date
2009
Start Page
292
End Page
300.97
DOI
10.1016/j.jaci.2009.05.022

Synaptic removal of diacylglycerol by DGKζ and PSD-95 regulates dendritic spine maintenance

Diacylglycerol (DAG) is an important lipid signalling molecule that exerts an effect on various effector proteins including protein kinase C. A main mechanism for DAG removal is to convert it to phosphatidic acid (PA) by DAG kinases (DGKs). However, it is not well understood how DGKs are targeted to specific subcellular sites and tightly regulates DAG levels. The neuronal synapse is a prominent site of DAG production. Here, we show that DGK is targeted to excitatory synapses through its direct interaction with the postsynaptic PDZ scaffold PSD-95. Overexpression of DGK in cultured neurons increases the number of dendritic spines, which receive the majority of excitatory synaptic inputs, in a manner requiring its catalytic activity and PSD-95 binding. Conversely, DGK knockdown reduces spine density. Mice deficient in DGK expression show reduced spine density and excitatory synaptic transmission. Time-lapse imaging indicates that DGK is required for spine maintenance but not formation. We propose that PSD-95 targets DGK to synaptic DAG-producing receptors to tightly couple synaptic DAG production to its conversion to PA for the maintenance of spine density.© 2009 European Molecular Biology Organization / All Rights Reserved.

Authors
Kim, K; Yang, J; Zhong, X-P; Kim, M-H; Kim, YS; Lee, HW; Han, S; Choi, J; Han, K; Seo, J; Prescott, SM; Topham, MK; Bae, YC; Koretzky, G; Choi, S-Y; Kim, E
MLA Citation
Kim, K, Yang, J, Zhong, X-P, Kim, M-H, Kim, YS, Lee, HW, Han, S, Choi, J, Han, K, Seo, J, Prescott, SM, Topham, MK, Bae, YC, Koretzky, G, Choi, S-Y, and Kim, E. "Synaptic removal of diacylglycerol by DGKζ and PSD-95 regulates dendritic spine maintenance." EMBO Journal 28.8 (2009): 1170-1179.
PMID
19229292
Source
scival
Published In
EMBO Journal
Volume
28
Issue
8
Publish Date
2009
Start Page
1170
End Page
1179
DOI
10.1038/emboj.2009.44

Diacylglycerol kinase ζ regulates actin cytoskeleton reorganization Through dissociation of rac1 from rhoGDI

Activation of Rac1 GTPase signaling is stimulated by phosphorylation and release of RhoGDI by the effector p21- activated kinase 1 (PAK1), but it is unclear what initiates this potential feed-forward mechanism for regulation of Rac activity. Phosphatidic acid (PA), which is produced from the lipid second messenger diacylglycerol (DAG) by the action of DAG kinases (DGKs), is known to activate PAK1. Here, we investigated whether PA produced by DGKζ initiates RhoGDI release and Rac1 activation. In DGKζ-deficient fibroblasts PAK1 phosphorylation and Rac1-RhoGDI dissociation were attenuated, leading to reduced Rac1 activation after platelet-derived growth factor stimulation. The cells were defective in Rac1-regulated behaviors, including lamellipodia formation, membrane ruffling, migration, and spreading. Wild-type DGKζ, but not a kinase-dead mutant, or addition of exogenous PA rescued Rac activation. DGKζ stably associated with PAK1 and RhoGDI, suggesting these proteins form a complex that functions as a Rac1-selective RhoGDI dissociation factor. These results define a pathway that links diacylglycerol, DGKζ, and PA to the activation of Rac1: the PA generated by DGKζ activates PAK1, which dissociates RhoGDI from Rac1 leading to changes in actin dynamics that facilitate the changes necessary for cell motility. © 2009 by The American Society for Cell Biology.

Authors
Abramovici, H; Mojtabaie, P; Parks, RJ; Zhong, X-P; Koretzky, GA; Topham, MK; Gee, SH
MLA Citation
Abramovici, H, Mojtabaie, P, Parks, RJ, Zhong, X-P, Koretzky, GA, Topham, MK, and Gee, SH. "Diacylglycerol kinase ζ regulates actin cytoskeleton reorganization Through dissociation of rac1 from rhoGDI." Molecular Biology of the Cell 20.7 (2009): 2049-2059.
PMID
19211846
Source
scival
Published In
Molecular Biology of the Cell
Volume
20
Issue
7
Publish Date
2009
Start Page
2049
End Page
2059
DOI
10.1091/mbc.E07-12-1248

Synergistic control of T cell development and tumor suppression by diacylglycerol kinase alpha and zeta.

Diacylglycerol (DAG) kinases (DGKs) are a family of enzymes that convert DAG to phosphatidic acid (PA), the physiologic functions of which have been poorly defined. We report here that DGK alpha and zeta synergistically promote T cell maturation in the thymus. Absence of both DGKalpha and zeta (DGKalpha(-/-)zeta(-/-)) results in a severe decrease in the number of CD4(+)CD8(-) and CD4(-)CD8(+) single-positive thymocytes correlating with increased DAG-mediated signaling. Positive selection, but not negative selection, is impaired in DGKalpha(-/-)zeta(-/-) mice. The developmental blockage in DGKalpha(-/-)zeta(-/-) mice can be partially overcome by treatment with PA. Furthermore, decreased DGK activity also promotes thymic lymphomagenesis accompanying elevated Ras and Erk1/2 activation. Our data demonstrate a synergistic and critical role of DGK isoforms in T cell development and tumor suppression, and indicate that DGKs not only terminate DAG signaling but also initiate PA signaling in thymocytes to promote positive selection.

Authors
Guo, R; Wan, C-K; Carpenter, JH; Mousallem, T; Boustany, R-MN; Kuan, C-T; Burks, AW; Zhong, X-P
MLA Citation
Guo, R, Wan, C-K, Carpenter, JH, Mousallem, T, Boustany, R-MN, Kuan, C-T, Burks, AW, and Zhong, X-P. "Synergistic control of T cell development and tumor suppression by diacylglycerol kinase alpha and zeta." Proc Natl Acad Sci U S A 105.33 (August 19, 2008): 11909-11914.
PMID
18689679
Source
pubmed
Published In
Proceedings of the National Academy of Sciences of USA
Volume
105
Issue
33
Publish Date
2008
Start Page
11909
End Page
11914
DOI
10.1073/pnas.0711856105

Diacylglycerol kinases in immune cell function and self-tolerance.

Both diacylglycerol (DAG) and phosphatidic acid (PA) are important second messengers involved in signal transduction from many immune cell receptors and can be generated and metabolized through multiple mechanisms. Recent studies indicate that diacylglycerol kinases (DGKs), the enzymes that catalyze phosphorylation of DAG to produce PA, play critical roles in regulating the functions of multiple immune cell lineages. In T cells, two DGK isoforms, alpha and zeta, inhibit DAG-mediated signaling following T-cell receptor engagement and prevent T-cell hyperactivation. DGK alpha and zeta synergistically promote T-cell anergy and are critical for T-cell tolerance. In mast cells, DGKzeta plays differential roles in their activation by promoting degranulation but attenuating cytokine production following engagement of the high affinity receptor for immunoglobulin E. In dendritic cells and macrophages, DGKzeta positively regulates Toll-like receptor-induced proinflammatory cytokine production through its product PA and is critical for host defense against Toxoplasma gondii infection. These studies demonstrate pivotal roles of DGKs in regulating immune cell function by acting both as signal terminator and initiator.

Authors
Zhong, X-P; Guo, R; Zhou, H; Liu, C; Wan, C-K
MLA Citation
Zhong, X-P, Guo, R, Zhou, H, Liu, C, and Wan, C-K. "Diacylglycerol kinases in immune cell function and self-tolerance." Immunol Rev 224 (August 2008): 249-264. (Review)
PMID
18759932
Source
pubmed
Published In
Immunological Reviews
Volume
224
Publish Date
2008
Start Page
249
End Page
264
DOI
10.1111/j.1600-065X.2008.00647.x

Diacylglycerol kinase zeta regulates microbial recognition and host resistance to Toxoplasma gondii.

Mammalian Toll-like receptors (TLRs) recognize microbial pathogen-associated molecular patterns and are critical for innate immunity against microbial infection. Diacylglycerol (DAG) kinases (DGKs) regulate the intracellular levels of two important second messengers involved in signaling from many surface receptors by converting DAG to phosphatidic acid (PA). We demonstrate that the zeta isoform of the DGK family (DGKzeta) is expressed in macrophages (Mphi) and dendritic cells. DGKzeta deficiency results in impaired interleukin (IL) 12 and tumor necrosis factor alpha production following TLR stimulation in vitro and in vivo, increased resistance to endotoxin shock, and enhanced susceptibility to Toxoplasma gondii infection. We further show that DGKzeta negatively controls the phosphatidylinositol 3-kinase (PI3K)-Akt pathway and that inhibition of PI3K activity or treatment with PA can restore lipopolysaccharide-induced IL-12 production by DGKzeta-deficient Mphi. Collectively, our data provide the first genetic evidence that an enzyme involved in DAG/PA metabolism plays an important role in innate immunity and indicate that DGKzeta promotes TLR responses via a pathway involving inhibition of PI3K.

Authors
Liu, C-H; Machado, FS; Guo, R; Nichols, KE; Burks, AW; Aliberti, JC; Zhong, X-P
MLA Citation
Liu, C-H, Machado, FS, Guo, R, Nichols, KE, Burks, AW, Aliberti, JC, and Zhong, X-P. "Diacylglycerol kinase zeta regulates microbial recognition and host resistance to Toxoplasma gondii." J Exp Med 204.4 (April 16, 2007): 781-792.
PMID
17371930
Source
pubmed
Published In
The Journal of Experimental Medicine
Volume
204
Issue
4
Publish Date
2007
Start Page
781
End Page
792
DOI
10.1084/jem.20061856

T-B+NK+ severe combined immunodeficiency caused by complete deficiency of the CD3zeta subunit of the T-cell antigen receptor complex.

CD3zeta is a subunit of the T-cell antigen receptor (TCR) complex required for its assembly and surface expression that also plays an important role in TCR-mediated signal transduction. We report here a patient with T(-)B(+)NK(+) severe combined immunodeficiency (SCID) who was homozygous for a single C insertion following nucleotide 411 in exon 7 of the CD3zeta gene. The few T cells present contained no detectable CD3zeta protein, expressed low levels of cell surface CD3epsilon, and were nonfunctional. CD4(+)CD8(-)CD3epsilon(low), CD4(-)CD8(+)CD3epsilon(low), and CD4(-)CD8(-)CD3epsilon(low) cells were detected in the periphery, and the patient also exhibited an unusual population of CD56(-)CD16(+) NK cells with diminished cytolytic activity. Additional studies demonstrated that retrovirally transduced patient mutant CD3zeta cDNA failed to rescue assembly of nascent complete TCR complexes or surface TCR expression in CD3zeta-deficient MA5.8 murine T-cell hybridoma cells. Nascent transduced mutant CD3zeta protein was also not detected in metabolically labeled MA5.8 cells, suggesting that it was unstable and rapidly degraded. Taken together, these findings provide the first demonstration that complete CD3zeta deficiency in humans can cause SCID by preventing normal TCR assembly and surface expression.

Authors
Roberts, JL; Lauritsen, JPH; Cooney, M; Parrott, RE; Sajaroff, EO; Win, CM; Keller, MD; Carpenter, JH; Carabana, J; Krangel, MS; Sarzotti, M; Zhong, X-P; Wiest, DL; Buckley, RH
MLA Citation
Roberts, JL, Lauritsen, JPH, Cooney, M, Parrott, RE, Sajaroff, EO, Win, CM, Keller, MD, Carpenter, JH, Carabana, J, Krangel, MS, Sarzotti, M, Zhong, X-P, Wiest, DL, and Buckley, RH. "T-B+NK+ severe combined immunodeficiency caused by complete deficiency of the CD3zeta subunit of the T-cell antigen receptor complex." Blood 109.8 (April 15, 2007): 3198-3206.
PMID
17170122
Source
pubmed
Published In
Blood
Volume
109
Issue
8
Publish Date
2007
Start Page
3198
End Page
3206
DOI
10.1182/blood-2006-08-043166

The role of diacylglycerol kinases in T cell anergy.

Engagement of the T cell antigen receptor (TCR) results in the activation of multiple biochemical second messenger cascades that must be integrated for the appropriate T cell response. Once the critical TCR-stimulated signaling pathway is initiated by activation of protein tyrosine kinases, a series of adapter proteins is recruited that brings tyrosine-phosphorylated phospholipase Cgamma1 into the vicinity of its substrate, phosphatidylinositol-4,5-bisphosphate, resulting in the formation of two second messengers, inositol-1,4,5-trisphosphate (IP3) and diacylglycerol (DAG). Previous work from multiple laboratories has shown that the balance between signals downstream of IP3 versus those downstream of DAG has profound effects on the fate of the stimulated T cells. In this report we summarize our recent data indicating that one key determinant of this balance of signals is the activity of members of the diacylglycerol kinase family, enzymes that convert DAG into phosphatidic acid.

Authors
Zhong, XP; Olenchock, BA; Koretzky, GA
MLA Citation
Zhong, XP, Olenchock, BA, and Koretzky, GA. "The role of diacylglycerol kinases in T cell anergy." Ernst Schering Foundation symposium proceedings 3 (2007): 139-149.
PMID
18510102
Source
scival
Published In
Ernst Schering Foundation symposium proceedings
Issue
3
Publish Date
2007
Start Page
139
End Page
149

Disruption of diacylglycerol metabolism impairs the induction of T cell anergy

Anergic T cells have altered diacylglycerol metabolism, but whether that altered metabolism has a causative function in the induction of T cell anergy is not apparent. To test the importance of diacylglycerol metabolism in T cell anergy, we manipulated diacylglycerol kinases (DGKs), which are enzymes that terminate diacylglycerol-dependent signaling. Overexpression of DGK-α resulted in a defect in T cell receptor signaling that is characteristic of anergy. We generated DGK-α-deficient mice and found that DGK-α-deficient T cells had more diacylglycerol-dependent T cell receptor signaling. In vivo anergy induction was impaired in DGK-α-deficient mice. When stimulated in anergy-producing conditions, T cells lacking DGK-α or DGK-ζ proliferated and produced interleukin 2. Pharmacological inhibition of DGK-α activity in DGK-ζ-deficient T cells that received an anergizing stimulus proliferated similarly to wild-type T cells that received CD28 costimulation and prevented anergy induction. Our findings suggest that regulation of diacylglycerol metabolism is critical in determining whether activation or anergy ensues after T cell receptor stimulation.

Authors
Olenchock, BA; Guo, R; Carpenter, JH; Jordan, M; Topham, MK; Koretzky, GA; Zhong, X-P
MLA Citation
Olenchock, BA, Guo, R, Carpenter, JH, Jordan, M, Topham, MK, Koretzky, GA, and Zhong, X-P. "Disruption of diacylglycerol metabolism impairs the induction of T cell anergy." Nature Immunology 7.11 (2006): 1174-1181.
PMID
17028587
Source
scival
Published In
Nature Immunology
Volume
7
Issue
11
Publish Date
2006
Start Page
1174
End Page
1181
DOI
10.1038/ni1400

Impaired degranulation but enhanced cytokine production after FcεRI stimulation of diacylglycerol kinase ζ-deficient mast cells

Calcium and diacylglycerol are critical second messengers that together effect mast cell degranulation after allergen cross-linking of immunoglobulin (Ig)E-bound FcεRI. Diacylglycerol kinase (DGK)ζ is a negative regulator of diacylglycerol-dependent signaling that acts by converting diacylglycerol to phosphatidic acid. We reported previously that DGKζ-/- mice have enhanced in vivo T cell function. Here, we demonstrate that these mice have diminished in vivo mast cell function, as revealed by impaired local anaphylactic responses. Concordantly, DGKζ-/- bone marrow-derived mast cells (BMMCs) demonstrate impaired degranulation after FcεRI cross-linking, associated with diminished phospholipase Cγ activity, calcium flux, and protein kinase C-βII membrane recruitment. In contrast, Ras-Erk signals and interleukin-6 production are enhanced, both during IgE sensitization and after antigen cross-linking of FcεRI. Our data demonstrate dissociation between cytokine production and degranulation in mast cells and reveal the importance of DGK activity during IgE sensitization for proper attenuation of FcεRI signals. JEM © The Rockefeller University Press.

Authors
Olenchock, BA; Guo, R; Silverman, MA; Wu, JN; Carpenter, JH; Koretzky, GA; Zhong, X-P
MLA Citation
Olenchock, BA, Guo, R, Silverman, MA, Wu, JN, Carpenter, JH, Koretzky, GA, and Zhong, X-P. "Impaired degranulation but enhanced cytokine production after FcεRI stimulation of diacylglycerol kinase ζ-deficient mast cells." Journal of Experimental Medicine 203.6 (2006): 1471-1480.
PMID
16717114
Source
scival
Published In
The Journal of Experimental Medicine
Volume
203
Issue
6
Publish Date
2006
Start Page
1471
End Page
1480
DOI
10.1084/jem.20052424

Transcriptional Regulation of Src Homology 2 Domain-Containing Leukocyte Phosphoprotein of 76 kDa: Dissection of Key Promoter Elements

SLP-76 (Src homology 2 domain-containing leukocyte phosphoprotein of 76 kDa) is an adaptor molecule expressed in all hemopoietic cell lineages except mature B cells and is known to play critical roles in the function of T cells, mast cells, and platelets and in vascular differentiation. Although great progress has been achieved in our understanding of SLP-76 function, little is known about the mechanisms regulating its expression. In this study we report the initial characterization of essential elements that control SLP-76 transcription. We identify several DNase I-hypersensitive sites in the SLP-76 locus, with a prominent site located in its promoter region. This site exists in T cells and monocytic cells, but not in B cells or fibroblasts. Using transient transfection assays, we identify a 507-bp fragment containing the 5′-untranslated region of the first exon and the immediate upstream sequence that confers transcriptional activation in T cells and monocytic cells, but not in B cells. Analysis of the 5′ ends of SLP-76 transcripts reveals differential regulation of SLP-76 transcription initiation between T cells and monocytic cells. Mutational and gel-shift analyses further indicate a critical role within this region for a binding site for Ets family transcription factors. The present study provides the first data to address the mechanisms controlling SLP-76 transcription by providing evidence for several key cis-regulatory elements in the promoter region.

Authors
Zhong, X-P; Maltzman, JS; Hainey, EA; Koretzky, GA
MLA Citation
Zhong, X-P, Maltzman, JS, Hainey, EA, and Koretzky, GA. "Transcriptional Regulation of Src Homology 2 Domain-Containing Leukocyte Phosphoprotein of 76 kDa: Dissection of Key Promoter Elements." Journal of Immunology 171.12 (2003): 6621-6629.
PMID
14662865
Source
scival
Published In
Journal of Immunology
Volume
171
Issue
12
Publish Date
2003
Start Page
6621
End Page
6629

Regulation of hematopoietic cell development and activation by adapter proteins

Adapter proteins, molecules with modular domains that mediate intermolecular interactions, play critical roles in the regulation of signaling events in all cell types. A major focus of our laboratory has been to examine the role of adapter molecules in hematopoietic cell development and activation. This review will describe the approaches we are taking to identify such proteins and to determine the mechanisms by which they exert their functions. This work represents the enormous efforts of the students and postdocs who have committed themselves to these projects, as well as the important collaborations we have developed with other investigators at the University of Pennsylvania and elsewhere.

Authors
Koretzky, GA; Abtahian, F; Derimanov, GS; Dmowski, SA; Guerriero, A; Jordan, MS; Maltzman, JS; Olenchock, BA; Singer, AL; Wu, JN; Zhong, X-P
MLA Citation
Koretzky, GA, Abtahian, F, Derimanov, GS, Dmowski, SA, Guerriero, A, Jordan, MS, Maltzman, JS, Olenchock, BA, Singer, AL, Wu, JN, and Zhong, X-P. "Regulation of hematopoietic cell development and activation by adapter proteins." Immunologic Research 27.2-3 (2003): 357-366.
PMID
12857981
Source
scival
Published In
Immunologic Research
Volume
27
Issue
2-3
Publish Date
2003
Start Page
357
End Page
366
DOI
10.1385/IR:27:2-3:357

Enhanced T cell responses due to diacylglycerol kinase ζ deficiency

Much is known about how T cell receptor (TCR) engagement leads to T cell activation; however, the mechanisms terminating TCR signaling remain less clear. Diacylglycerol, generated after TCR ligation, is essential in T cells. Its function must be controlled tightly to maintain normal T cell homeostasis. Previous studies have shown that diacylglycerol kinase ζ (DGKζ), which converts diacylglycerol to phosphatidic acid, can inhibit TCR signaling. Here we show that DGKζ-deficient T cells are hyperresponsive to TCR stimulation both ex vivo and in vivo. Furthermore, DGKζ-deficient mice mounted a more robust immune response to lymphocytic choriomeningitis virus infection than did wild-type mice. These results demonstrate the importance of DGKζ as a physiological negative regulator of TCR signaling and T cell activation.

Authors
Zhong, X-P; Hainey, EA; Olenchock, BA; Jordan, MS; Maltzman, JS; Nichols, KE; Shen, H; Koretzky, GA
MLA Citation
Zhong, X-P, Hainey, EA, Olenchock, BA, Jordan, MS, Maltzman, JS, Nichols, KE, Shen, H, and Koretzky, GA. "Enhanced T cell responses due to diacylglycerol kinase ζ deficiency." Nature Immunology 4.9 (2003): 882-890.
PMID
12883552
Source
scival
Published In
Nature Immunology
Volume
4
Issue
9
Publish Date
2003
Start Page
882
End Page
890
DOI
10.1038/ni958

Regulation of T cell receptor-induced activation of the Ras-ERK pathway by diacylglycerol kinase ζ

T cell development in the thymus and activation of mature T cells in the periphery depend on signals stimulated by engagement of the T cell antigen receptor (TCR). Among the second messenger cascades initiated by TCR ligation include the phosphatidylinositol pathway where the membrane phospholipid, phosphatidylinositol 4,5-bisphosphate, is hydrolyzed to inositol 1,4,5-trisphosphate and diacylglycerol (DAG). Inositol 1,4,5-trisphosphate signals a rise in intracellular free calcium, leading to translocation of nuclear factor of activated T cells into the nucleus. DAG activates Ras-GRP and protein kinase C θ. Because both RasGRP and protein kinase C θ are essential for thymocyte and T cell function, it is critical to understand how DAG is regulated. In this report, we demonstrate expression of DAG kinase ζ (DGKζ, the enzyme that catalyzes the conversion of DAG to phosphatidic acid) in multiple lymphoid organs, with highest expression observed within the T cell compartment. Overexpression studies in Jurkat T cells indicate that DGKζ interferes with TCR-induced Ras and ERK activation, AP-1 induction, and expression of the activation marker CD69. In contrast, TCR-stimulated calcium influx is not altered. Mutational analysis indicates that the kinase and DAG binding domains, but not the ankyrin repeats of DGKζ, are required for its inhibitory effects. Collectively these studies demonstrate a potential role of DGKζ to function as a selective negative regulator of DAG signaling on T cell activation and provide the first structure/function analysis of this enzyme in T cells.

Authors
Zhong, X-P; Hainey, EA; Olenchock, BA; Zhao, H; Topham, MK; Koretzky, GA
MLA Citation
Zhong, X-P, Hainey, EA, Olenchock, BA, Zhao, H, Topham, MK, and Koretzky, GA. "Regulation of T cell receptor-induced activation of the Ras-ERK pathway by diacylglycerol kinase ζ." Journal of Biological Chemistry 277.34 (2002): 31089-31098.
PMID
12070163
Source
scival
Published In
The Journal of biological chemistry
Volume
277
Issue
34
Publish Date
2002
Start Page
31089
End Page
31098
DOI
10.1074/jbc.M203818200

Assessing a role for enhancer-blocking activity in gene regulation within the murine T-cell receptor alpha/delta locus.

Although situated close together within the T-cell receptor (TCR) alpha/delta locus, TCR delta and TCR alpha gene segments are controlled by two developmental stage-specific enhancers and are activated according to distinct developmental programmes. We previously used a stable transfection colony assay to identify an enhancer-blocking element, blocking element alpha/delta-1 (BEAD-1), between the TCR delta and alpha gene segments of the human TCR alpha/delta locus. We hypothesized that enhancer-blocking by BEAD-1 might be required to prevent the TCR delta enhancer from activating TCR alpha gene segment transcription and rearrangement at the double negative stage of thymocyte development. Here, we used a transfection approach to define partial enhancer-blocking activity in an analogous position of the murine TCR alpha/delta locus. To test the functional significance of this activity in vivo, we used gene targeting to delete the region from the endogenous locus. We found no perturbation of TCR delta and TCR alpha gene expression and rearrangement on targeted alleles, indicating that enhancer-blocking activity in this region is not required to maintain the developmentally distinct activation profiles of the two genes. We suggest that appropriate regulation may be achieved as a result of intrinsic biases in enhancer-promoter interactions or a developmental stage specificity to promoter function that is distinct from any additional specificity imposed by the enhancers themselves.

Authors
Sleckman, BP; Carabana, J; Zhong, X; Krangel, MS
MLA Citation
Sleckman, BP, Carabana, J, Zhong, X, and Krangel, MS. "Assessing a role for enhancer-blocking activity in gene regulation within the murine T-cell receptor alpha/delta locus." Immunology 104.1 (September 2001): 11-18.
PMID
11576215
Source
pubmed
Published In
Immunology
Volume
104
Issue
1
Publish Date
2001
Start Page
11
End Page
18

Accessibility control of T cell receptor gene rearrangement in developing thymocytes. The TCR alpha/delta locus.

The joining of T cell receptor (TCR) and immunoglobulin (Ig) gene segments through the process of V(D)J recombination occurs in a lineage-specific and developmental-stage-specific way during the early stages of lymphocyte development. Such developmental regulation is thought to be mediated through the control of gene segment accessibility to the recombinase. We have studied the regulation of V(D)J recombination at the TCR alpha/delta locus, because this locus provides a fascinating model in which distinct sets of gene segments are activated at different stages of T cell development. The transcriptional enhancers Edelta and Ealpha have been implicated as critical regulators that, in conjunction with other cis-acting elements, confer region-specific and developmental-stage-specific changes in gene segment accessibility within TCR alpha/delta locus chromatin. Current work suggests that they may do so by functioning as regional modulators of histone acetylation.

Authors
Krangel, MS; McMurry, MT; Hernandez-Munain, C; Zhong, XP; Carabana, J
MLA Citation
Krangel, MS, McMurry, MT, Hernandez-Munain, C, Zhong, XP, and Carabana, J. "Accessibility control of T cell receptor gene rearrangement in developing thymocytes. The TCR alpha/delta locus." Immunol Res 22.2-3 (2000): 127-135. (Review)
PMID
11339350
Source
pubmed
Published In
Immunologic Research
Volume
22
Issue
2-3
Publish Date
2000
Start Page
127
End Page
135
DOI
10.1385/IR:22:2-3:127

Flanking nuclear matrix attachment regions synergize with the T cell receptor delta enhancer to promote V(D)J recombination.

Previous studies have identified nuclear matrix attachment regions (MARs) that are closely associated with transcriptional enhancers in the IgH, Igkappa, and T cell receptor (TCR) beta loci, but have yielded conflicting information regarding their functional significance. In this report, a combination of in vitro and in situ mapping approaches was used to localize three MARs associated with the human TCR delta gene. Two of these are located within the Jdelta3-Cdelta intron, flanking the core TCR delta enhancer (Edelta) both 5' and 3' in a fashion reminiscent of the Ig heavy chain intronic enhancer-associated MARs. The third is located about 20 kb upstream, tightly linked to Ddelta1 and Ddelta2. We have previously used a transgenic minilocus V(D)J recombination reporter to establish that Edelta functions as a developmental regulator of V(D)J recombination, and that it does so by modulating substrate accessibility to the V(D)J recombinase. We show here that the Edelta-associated MARs function synergistically with the core Edelta to promote V(D)J recombination in this system, as they are required for enhancer-dependent transgene rearrangement in single-copy transgene integrants.

Authors
Zhong, XP; Carabaña, J; Krangel, MS
MLA Citation
Zhong, XP, Carabaña, J, and Krangel, MS. "Flanking nuclear matrix attachment regions synergize with the T cell receptor delta enhancer to promote V(D)J recombination." Proc Natl Acad Sci U S A 96.21 (October 12, 1999): 11970-11975.
PMID
10518560
Source
pubmed
Published In
Proceedings of the National Academy of Sciences of USA
Volume
96
Issue
21
Publish Date
1999
Start Page
11970
End Page
11975

Enhancer-blocking activity within the DNase I hypersensitive site 2 to 6 region between the TCR alpha and Dad1 genes.

Although tightly linked, the TCR alpha and delta genes are expressed specifically in T lymphocytes, whereas the Dad1 gene is ubiquitously expressed. Between TCR alpha and Dad1 are eight DNase I hypersensitive sites (HS). HS1 colocalizes with the TCR alpha enhancer (Ealpha) and is T cell-specific; HS2, -3, -4, -5, and -6 map downstream of HS1 and are tissue-nonspecific. The region spanning HS2-6 was reported to display chromatin-opening activity and to confer copy number-dependent and integration site-independent transgene expression in transgenic mice. Here, we demonstrate that HS2-6 also displays enhancer-blocking activity, as it can block an enhancer from activating a promoter when located between the two in a chromatin-integrated context, and can do so without repressing either the enhancer or the promoter. Multiple enhancer-blocking elements are arrayed across HS2-6. We show that HS2-6 by itself does not activate transcription in chromatin context, but can synergize with an enhancer when located upstream of an enhancer and promoter. We propose that HS2-6 primarily functions as an insulator or boundary element that may be critical for the autonomous regulation of the TCR alpha and Dad1 genes.

Authors
Zhong, XP; Krangel, MS
MLA Citation
Zhong, XP, and Krangel, MS. "Enhancer-blocking activity within the DNase I hypersensitive site 2 to 6 region between the TCR alpha and Dad1 genes." J Immunol 163.1 (July 1, 1999): 295-300.
PMID
10384128
Source
pubmed
Published In
Journal of immunology (Baltimore, Md. : 1950)
Volume
163
Issue
1
Publish Date
1999
Start Page
295
End Page
300

Developmental regulation of V(D)J recombination at the TCR alpha/delta locus.

The T-cell receptor (TCR) alpha/delta locus includes a large number of V, D, J and C gene segments that are used to produce functional TCR delta and TCR alpha chains expressed by distinct subsets of T lymphocytes. V(D)J recombination events within the locus are regulated as a function of developmental stage and cell lineage during T-lymphocyte differentiation in the thymus. The process of V(D)J recombination is regulated by cis-acting elements that modulate the accessibility of chromosomal substrates to the recombinase. Here we evaluate how the assembly of transcription factor complexes onto enhancers, promoters and other regulatory elements within the TCR alpha/delta locus imparts developmental control to VDJ delta and VJ alpha rearrangement events. Furthermore, we develop the notion that within a complex locus such as the TCR alpha/delta locus, highly localized and region-specific control is likely to require an interplay between positive regulatory elements and blocking or boundary elements that restrict the influence of the positive elements to defined regions of the locus.

Authors
Krangel, MS; Hernandez-Munain, C; Lauzurica, P; McMurry, M; Roberts, JL; Zhong, XP
MLA Citation
Krangel, MS, Hernandez-Munain, C, Lauzurica, P, McMurry, M, Roberts, JL, and Zhong, XP. "Developmental regulation of V(D)J recombination at the TCR alpha/delta locus." Immunol Rev 165 (October 1998): 131-147. (Review)
PMID
9850858
Source
pubmed
Published In
Immunological Reviews
Volume
165
Publish Date
1998
Start Page
131
End Page
147

An enhancer-blocking element between alpha and delta gene segments within the human T cell receptor alpha/delta locus.

T cell receptor (TCR) alpha and delta gene segments are organized within a single genetic locus but are differentially regulated during T cell development. An enhancer-blocking element (BEAD-1, for blocking element alpha/delta 1) was localized to a 2.0-kb region 3' of TCR delta gene segments and 5' of TCR alpha joining gene segments within this locus. BEAD-1 blocked the ability of the TCR delta enhancer (Edelta) to activate a promoter when located between the two in a chromatin-integrated construct. We propose that BEAD-1 functions as a boundary that separates the TCR alpha/delta locus into distinct regulatory domains controlled by Edelta and the TCR alpha enhancer, and that it prevents Edelta from opening the chromatin of the TCR alpha joining gene segments for VDJ recombination at an early stage of T cell development.

Authors
Zhong, XP; Krangel, MS
MLA Citation
Zhong, XP, and Krangel, MS. "An enhancer-blocking element between alpha and delta gene segments within the human T cell receptor alpha/delta locus." Proc Natl Acad Sci U S A 94.10 (May 13, 1997): 5219-5224.
PMID
9144218
Source
pubmed
Published In
Proceedings of the National Academy of Sciences of USA
Volume
94
Issue
10
Publish Date
1997
Start Page
5219
End Page
5224

Regulation of T cell receptor delta gene rearrangement by CBF/PEBP2.

We have analyzed transgenic mice carrying versions of a human T cell receptor (TCR)-delta gene minilocus to study the developmental control of VDJ (variable/diversity/joining) recombination. Previous data indicated that a 1.4-kb DNA fragment carrying the TCR-delta enhancer (E(delta)) efficiently activates minilocus VDJ recombination in vivo. We tested whether the transcription factor CBF/PEBP2 plays an important role in the ability of E(delta) to activate VDJ recombination by analyzing VDJ recombination in mice carrying a minilocus in which the deltaE3 element of E(delta) includes a mutated CBF/PEBP2 binding site. The enhancer-dependent VD to J step of minilocus rearrangement was dramatically inhibited in three of four transgenic lines, arguing that the binding of CBF/PEBP2 plays a role in modulating local accessibility to the VDJ recombinase in vivo. Because mutation of the deltaE3 binding site for the transcription factor c-Myb had previously established a similar role for c-Myb, and because a 60-bp fragment of E(delta) carrying deltaE3 and deltaE4 binding sites for CBF/PEBP2, c-Myb, and GATA-3 displays significant enhancer activity in transient transfection experiments, we tested whether this fragment of E(delta) is sufficient to activate VDJ recombination in vivo. This fragment failed to efficiently activate the enhancer-dependent VD to J step of minilocus rearrangement in all three transgenic lines examined, indicating that the binding of CBF/PEBP2 and c-Myb to their cognate sites within E(delta), although necessary, is not sufficient for the activation of VDJ recombination by E(delta). These results imply that CBF/PEBP2 and c-Myb collaborate with additional factors that bind elsewhere within E(delta) to modulate local accessibility to the VDJ recombinase in vivo.

Authors
Lauzurica, P; Zhong, XP; Krangel, MS; Roberts, JL
MLA Citation
Lauzurica, P, Zhong, XP, Krangel, MS, and Roberts, JL. "Regulation of T cell receptor delta gene rearrangement by CBF/PEBP2." J Exp Med 185.7 (April 7, 1997): 1193-1201.
PMID
9104806
Source
pubmed
Published In
The Journal of Experimental Medicine
Volume
185
Issue
7
Publish Date
1997
Start Page
1193
End Page
1201

Diacylglycerol Kinase Zeta Positively Controls the Development of iNKT-17 Cells.

Authors
Wu, J; Shen, S; Yang, J; Xia, Z; Zhong, XP
MLA Citation
Wu, J, Shen, S, Yang, J, Xia, Z, and Zhong, XP. "Diacylglycerol Kinase Zeta Positively Controls the Development of iNKT-17 Cells." PLoS One 8.9. (Academic Article)
Source
manual
Published In
PLoS One
Volume
8
Issue
9

Regulation of Lipid Signaling by Diacylglycerol Kinases during T Cell Development and Function.

Authors
Krishna, S; Zhong, XP
MLA Citation
Krishna, S, and Zhong, XP. "Regulation of Lipid Signaling by Diacylglycerol Kinases during T Cell Development and Function." Front Immunol 4.178. (Review)
PMID
23847619
Source
manual
Published In
Front Immunol
Volume
4
Issue
178

T cell Receptor Signal Transduction in T lymphocytes

Authors
Gorentla, BK; Zhong, XP
MLA Citation
Gorentla, BK, and Zhong, XP. "T cell Receptor Signal Transduction in T lymphocytes." J Clin Cell Immunol 2012.(Suppl 12). (Review)
Source
manual
Published In
J Clin Cell Immunol
Volume
2012
Issue
(Suppl 12)

Role of diacylglycerol kinases in T cell development and function

Authors
Krishna, S; Zhong, XP
MLA Citation
Krishna, S, and Zhong, XP. "Role of diacylglycerol kinases in T cell development and function." Crit Rev Immunol 33.2: 97-118. (Review)
Source
manual
Published In
Crit Rev Immunol
Volume
33
Issue
2
Start Page
97
End Page
118

Diacylglycerol Kinase ζ Limits B Cell Antigen Receptor-Dependent Activation of ERK Signaling to Inhibit Early Antibody Responses

Authors
Wheeler, ML; Dong, MB; Brink, R; Zhong, XP; Defranco, AL
MLA Citation
Wheeler, ML, Dong, MB, Brink, R, Zhong, XP, and Defranco, AL. "Diacylglycerol Kinase ζ Limits B Cell Antigen Receptor-Dependent Activation of ERK Signaling to Inhibit Early Antibody Responses." Sci Signal 6.297. (Academic Article)
PMID
24129701
Source
manual
Published In
Sci Signal
Volume
6
Issue
297
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Research Areas:

  • Adaptive Immunity
  • Adjuvants, Immunologic
  • Administration, Oral
  • Anacardium
  • Anaphylaxis
  • Antigen Presentation
  • Antigens, Bacterial
  • Antigens, CD28
  • Antigens, CD3
  • Antigens, CD4
  • Antigens, CD45
  • Antigens, CD8
  • Antigens, Plant
  • Apoptosis
  • Arachis hypogaea
  • Basophils
  • Bone Marrow
  • Bone Marrow Cells
  • CD4-Positive T-Lymphocytes
  • Cell Death
  • Cell Degranulation
  • Cell Differentiation
  • Cell Lineage
  • Cell Proliferation
  • Cell Transformation, Neoplastic
  • Child, Preschool
  • Chromatin Immunoprecipitation
  • DNA Nucleotidyltransferases
  • Dendritic Cells
  • Desensitization, Immunologic
  • Diacylglycerol Kinase
  • Diglycerides
  • Disease Models, Animal
  • Down-Regulation
  • Drosophila
  • Enhancer Elements, Genetic
  • Exons
  • Family
  • Female
  • Forkhead Transcription Factors
  • Gene Expression
  • Gene Expression Regulation
  • Gene Expression Regulation, Enzymologic
  • Gene Targeting
  • Genes, Immunoglobulin
  • Guanine Nucleotide Exchange Factors
  • Histocompatibility Antigens Class II
  • Homeostasis
  • Homozygote
  • Humans
  • Hypertrophy
  • I-kappa B Proteins
  • Immune Tolerance
  • Immunity, Innate
  • Immunoglobulin E
  • Immunoglobulin G
  • Immunosuppression
  • Immunotherapy
  • Inducible T-Cell Co-Stimulator Protein
  • Interferon Regulatory Factors
  • Interferon-gamma
  • Interleukin-12
  • Interleukin-17
  • Interleukin-2
  • Jurkat Cells
  • Killer Cells, Natural
  • Loss of Heterozygosity
  • Lung Neoplasms
  • Lymphocyte Activation
  • Lymphocytic Choriomeningitis
  • Lymphopenia
  • Macrophages
  • Male
  • Mast Cells
  • Melanoma, Experimental
  • Mice
  • Mice, Inbred C3H
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Mice, Transgenic
  • Microscopy, Fluorescence
  • Mitogen-Activated Protein Kinase 1
  • Mitogen-Activated Protein Kinase 3
  • Mitogen-Activated Protein Kinase 8
  • Mitogen-Activated Protein Kinase 9
  • Mitogen-Activated Protein Kinases
  • Models, Biological
  • Muscle Proteins
  • Muscle, Skeletal
  • Mutagenesis, Insertional
  • Natural Killer T-Cells
  • Neoplasm Proteins
  • Nut Hypersensitivity
  • Oligodeoxyribonucleotides
  • Organ Size
  • Peanut Hypersensitivity
  • Pepsin A
  • Phosphatidic Acids
  • Phosphatidylinositol 3-Kinases
  • Phospholipase D
  • Polymorphism, Single Nucleotide
  • Promoter Regions, Genetic
  • Protein Isoforms
  • Protein Kinase Inhibitors
  • Proto-Oncogene Proteins c-akt
  • RNA Interference
  • RNA, Small Interfering
  • Receptors, Antigen, T-Cell
  • Receptors, Antigen, T-Cell, alpha-beta
  • Receptors, Antigen, T-Cell, gamma-delta
  • Receptors, IgE
  • Recombinant Fusion Proteins
  • Self Tolerance
  • Signal Transduction
  • Skin Tests
  • Spleen
  • Survival Rate
  • T-Lymphocyte Subsets
  • T-Lymphocytes
  • T-Lymphocytes, Regulatory
  • TOR Serine-Threonine Kinases
  • Th1 Cells
  • Th2 Cells
  • Thymocytes
  • Toll-Like Receptor 4
  • Toll-Like Receptors
  • Toxoplasma
  • Toxoplasmosis
  • Trans-Activators
  • Transcription, Genetic
  • Transduction, Genetic
  • Transfection
  • Tuberous Sclerosis
  • Tumor Necrosis Factor-alpha
  • Tumor Suppressor Proteins
  • Uniparental Disomy
  • VDJ Recombinases
  • ras Proteins