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Joachim A, Aussel R, Gélard L, Zhang F, Mori D, Grégoire C, Villazala Merino S, Gaya M, Liang Y, Malissen M, Malissen B. Defective LAT signalosome pathology in mice mimics human IgG4-related disease at single-cell level. J Exp Med 2023; 220:e20231028. [PMID: 37624388 PMCID: PMC10457416 DOI: 10.1084/jem.20231028] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 07/25/2023] [Accepted: 08/08/2023] [Indexed: 08/26/2023] Open
Abstract
Mice with a loss-of-function mutation in the LAT adaptor (LatY136F) develop an autoimmune and type 2 inflammatory disorder called defective LAT signalosome pathology (DLSP). We analyzed via single-cell omics the trajectory leading to LatY136F DLSP and the underlying CD4+ T cell diversification. T follicular helper cells, CD4+ cytotoxic T cells, activated B cells, and plasma cells were found in LatY136F spleen and lung. Such cell constellation entailed all the cell types causative of human IgG4-related disease (IgG4-RD), an autoimmune and inflammatory condition with LatY136F DLSP-like histopathological manifestations. Most previously described T cell-mediated autoimmune manifestations require persistent TCR input. In contrast, following their first engagement by self-antigens, the autoreactive TCR expressed by LatY136F CD4+ T cells hand over their central role in T cell activation to CD28 costimulatory molecules. As a result, all subsequent LatY136F DLSP manifestations, including the production of autoantibodies, solely rely on CD28 engagement. Our findings elucidate the etiology of the LatY136F DLSP and qualify it as a model of IgG4-RD.
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Affiliation(s)
- Anais Joachim
- Aix Marseille Université, INSERM, CNRS, Centre d’Immunologie de Marseille-Luminy, Marseille, France
| | - Rudy Aussel
- Aix Marseille Université, INSERM, CNRS, Centre d’Immunologie de Marseille-Luminy, Marseille, France
| | - Léna Gélard
- Aix Marseille Université, INSERM, CNRS, Centre d’Immunologie de Marseille-Luminy, Marseille, France
- Centre d’Immunophénomique, INSERM, CNRS, Aix Marseille Université, Marseille, France
| | - Fanghui Zhang
- Aix Marseille Université, INSERM, CNRS, Centre d’Immunologie de Marseille-Luminy, Marseille, France
- School of Laboratory Medicine, Henan Key Laboratory for Immunology and Targeted Therapy, Xinxiang Medical University, Xinxiang, China
| | - Daiki Mori
- Aix Marseille Université, INSERM, CNRS, Centre d’Immunologie de Marseille-Luminy, Marseille, France
- Centre d’Immunophénomique, INSERM, CNRS, Aix Marseille Université, Marseille, France
| | - Claude Grégoire
- Aix Marseille Université, INSERM, CNRS, Centre d’Immunologie de Marseille-Luminy, Marseille, France
| | - Sergio Villazala Merino
- Aix Marseille Université, INSERM, CNRS, Centre d’Immunologie de Marseille-Luminy, Marseille, France
| | - Mauro Gaya
- Aix Marseille Université, INSERM, CNRS, Centre d’Immunologie de Marseille-Luminy, Marseille, France
| | - Yinming Liang
- School of Laboratory Medicine, Henan Key Laboratory for Immunology and Targeted Therapy, Xinxiang Medical University, Xinxiang, China
| | - Marie Malissen
- Aix Marseille Université, INSERM, CNRS, Centre d’Immunologie de Marseille-Luminy, Marseille, France
- Centre d’Immunophénomique, INSERM, CNRS, Aix Marseille Université, Marseille, France
- Laboratory of Immunophenomics, School of Laboratory Medicine, Xinxiang Medical University, Xinxiang, China
| | - Bernard Malissen
- Aix Marseille Université, INSERM, CNRS, Centre d’Immunologie de Marseille-Luminy, Marseille, France
- Centre d’Immunophénomique, INSERM, CNRS, Aix Marseille Université, Marseille, France
- Laboratory of Immunophenomics, School of Laboratory Medicine, Xinxiang Medical University, Xinxiang, China
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Tripathi S, Tsang JS, Park K. Systems immunology of regulatory T cells: can one circuit explain it all? Trends Immunol 2023; 44:766-781. [PMID: 37690962 PMCID: PMC10543564 DOI: 10.1016/j.it.2023.08.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 08/11/2023] [Accepted: 08/12/2023] [Indexed: 09/12/2023]
Abstract
Regulatory T (Treg) cells play vital roles in immune homeostasis and response, including discrimination between self- and non-self-antigens, containment of immunopathology, and inflammation resolution. These diverse functions are orchestrated by cellular circuits involving Tregs and other cell types across space and time. Despite dramatic progress in our understanding of Treg biology, a quantitative framework capturing how Treg-containing circuits give rise to these diverse functions is lacking. Here, we propose that different facets of Treg function can be interpreted as distinct operating regimes of the same underlying circuit. We discuss how a systems immunology approach, involving quantitative experiments, computational modeling, and machine learning, can advance our understanding of Treg function, and help identify general operating and design principles underlying immune regulation.
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Affiliation(s)
- Shubham Tripathi
- Yale Center for Systems and Engineering Immunology and Department of Immunobiology, Yale School of Medicine, New Haven, CT 06520, USA.
| | - John S Tsang
- Yale Center for Systems and Engineering Immunology and Department of Immunobiology, Yale School of Medicine, New Haven, CT 06520, USA; Department of Biomedical Engineering, Yale University, New Haven, CT 06520, USA; Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, Bethesda, MD 20892, USA.
| | - Kyemyung Park
- Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, Bethesda, MD 20892, USA; Graduate School of Health Science and Technology and Department of Biomedical Engineering, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea.
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Fernández-Aguilar LM, Vico-Barranco I, Arbulo-Echevarria MM, Aguado E. A Story of Kinases and Adaptors: The Role of Lck, ZAP-70 and LAT in Switch Panel Governing T-Cell Development and Activation. BIOLOGY 2023; 12:1163. [PMID: 37759563 PMCID: PMC10525366 DOI: 10.3390/biology12091163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 08/18/2023] [Accepted: 08/20/2023] [Indexed: 09/29/2023]
Abstract
Specific antigen recognition is one of the immune system's features that allows it to mount intense yet controlled responses to an infinity of potential threats. T cells play a relevant role in the host defense and the clearance of pathogens by means of the specific recognition of peptide antigens presented by antigen-presenting cells (APCs), and, to do so, they are equipped with a clonally distributed antigen receptor called the T-cell receptor (TCR). Upon the specific engagement of the TCR, multiple intracellular signals are triggered, which lead to the activation, proliferation and differentiation of T lymphocytes into effector cells. In addition, this signaling cascade also operates during T-cell development, allowing for the generation of cells that can be helpful in the defense against threats, as well as preventing the generation of autoreactive cells. Early TCR signals include phosphorylation events in which the tyrosine kinases Lck and ZAP70 are involved. The sequential activation of these kinases leads to the phosphorylation of the transmembrane adaptor LAT, which constitutes a signaling hub for the generation of a signalosome, finally resulting in T-cell activation. These early signals play a relevant role in triggering the development, activation, proliferation and apoptosis of T cells, and the negative regulation of these signals is key to avoid aberrant processes that could generate inappropriate cellular responses and disease. In this review, we will examine and discuss the roles of the tyrosine kinases Lck and ZAP70 and the membrane adaptor LAT in these cellular processes.
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Grants
- PY20_01297 Consejería de Transformación Económica, Industria, Conocimiento y Universidades, Junta de Andalucía, Spain
- PID2020-113943RB-I00 Agencia Estatal de Investigación, Ministerio de Ciencia e Innovación, Spain
- PR2022-037 University of Cádiz
- PAIDI2020/DOC_01433 Consejería de Transformación Económica, Industria, Conocimiento y Universidades, Junta de Andalucía, Spain
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Affiliation(s)
- Luis M. Fernández-Aguilar
- Institute for Biomedical Research of Cadiz (INIBICA), 11009 Cadiz, Spain; (L.M.F.-A.); (I.V.-B.); (M.M.A.-E.)
- Department of Biomedicine, Biotechnology and Public Health (Immunology), University of Cadiz, 11002 Cadiz, Spain
| | - Inmaculada Vico-Barranco
- Institute for Biomedical Research of Cadiz (INIBICA), 11009 Cadiz, Spain; (L.M.F.-A.); (I.V.-B.); (M.M.A.-E.)
- Department of Biomedicine, Biotechnology and Public Health (Immunology), University of Cadiz, 11002 Cadiz, Spain
| | - Mikel M. Arbulo-Echevarria
- Institute for Biomedical Research of Cadiz (INIBICA), 11009 Cadiz, Spain; (L.M.F.-A.); (I.V.-B.); (M.M.A.-E.)
- Department of Biomedicine, Biotechnology and Public Health (Immunology), University of Cadiz, 11002 Cadiz, Spain
| | - Enrique Aguado
- Institute for Biomedical Research of Cadiz (INIBICA), 11009 Cadiz, Spain; (L.M.F.-A.); (I.V.-B.); (M.M.A.-E.)
- Department of Biomedicine, Biotechnology and Public Health (Immunology), University of Cadiz, 11002 Cadiz, Spain
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Human umbilical cord blood-derived MSCs trans-differentiate into endometrial cells and regulate Th17/Treg balance through NF-κB signaling in rabbit intrauterine adhesions endometrium. Stem Cell Res Ther 2022; 13:301. [PMID: 35841027 PMCID: PMC9284747 DOI: 10.1186/s13287-022-02990-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2022] [Accepted: 04/21/2022] [Indexed: 12/03/2022] Open
Abstract
Purpose The fundamental cause of intrauterine adhesions (IUAs) is the destruction and reduction in stem cells in endometrial basal layer, resulting in endometrial reconstruction very difficult. The purpose of this study was to investigate the effects and underlying mechanism of human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs) on the endometrial reconstruction after transplantation. Methods hUCB-MSCs were isolated and identified by flow cytometry, osteogenic, adipogenic and chondrogenic differentiation assays. The rabbit IUA models were established and set five groups (control, 14/28th day after surgery, estrogen and hUCB-MSCs treatment). The number of endometrial glands and the fibrosis rate were evaluated using HE and Masson staining, respectively. Endometrial proliferation, angiogenesis and inflammation were evaluated by immunohistochemical staining of ER, Ki-67and TGF-β1, respectively. Single-cell RNA sequencing (scRNA-seq) was applied to explore the cell differentiation trajectory after hUCB-MSCs transplanted into IUA endometrium. Finally, molecular mechanism of hUCB-MSCs repairing damaged endometrium was investigated by RNA sequencing, qRT-PCR and Western blot assays. Results After transplantation of the hUCB-MSCs, the increase in endometrial gland number, estrogen receptor (ER) and Ki-67 expression, and the decrease in fibrosis rate and TGF-β expression (P < 0.05), suggested the endometrial repair, angiogenesis and inflammatory suppression. The therapeutic effect of hUCB-MSCs was significantly improved compared with 28th day after surgery and estrogen group. ScRNA-seq demonstrated that the transplanted hUCB-MSCs can trans-differentiate into endometrial cells: epithelial, fibroblast and macrophage. RNA sequencing of six IUA samples combined with qRT-PCR and Western blot assays further revealed that hUCB-MSCs may regulate Th17/Treg balance through NF-κB signaling, thus inhibiting the immune response of damaged endometrium. Conclusions Our study demonstrated that hUCB-MSCs can repair damaged endometrium through trans-differentiation, immunomodulatory capacities and NF-κB signaling, suggesting the treatment value of hUCB-MSCs in IUA. Supplementary Information The online version contains supplementary material available at 10.1186/s13287-022-02990-1.
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5
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Th1-like Treg in vitiligo: An incompetent regulator in immune tolerance. J Autoimmun 2022; 131:102859. [DOI: 10.1016/j.jaut.2022.102859] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 06/15/2022] [Accepted: 06/17/2022] [Indexed: 11/21/2022]
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O'Brien SA, Zhu M, Zhang W. Spontaneous Differentiation of T Follicular Helper Cells in LATY136F Mutant Mice. Front Immunol 2021; 12:656817. [PMID: 33912184 PMCID: PMC8072119 DOI: 10.3389/fimmu.2021.656817] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 03/22/2021] [Indexed: 11/29/2022] Open
Abstract
Mice with a mutation at the LAT-PLCγ1 binding site (Y136) have a defect in thymocyte development due to dampened TCR signaling. CD4+ T cells that do reach the periphery are hyper-activated and skewed to Th2. Over time, these mice develop an autoimmune-like syndrome, characterize by overproduction of Th2 cytokines, T cell infiltration into various organs, and B cell activation, isotype switching, and autoantibody production. In this study, we examined IL4 production by CD4+ T cells in the LATY136F mice using the KN2 reporter mice, in which human CD2 expression marks T cells that are actively producing IL4 protein. We showed that these mice had spontaneous Tfh differentiation. Despite the fact that the majority of CD4+ T cells were skewed to Th2 and were GATA3+, only a small subset of them were actively secreting IL4. These T cells were Tfh cells that expressed BCL6 and were localized to B cell-rich germinal centers within the spleen. Interestingly, these Tfh cells expressed high levels of both BCL6 and GATA3. By using LAT conditional knockout mice that inducibly express only the LATY136F allele, we further showed that Tfh cell differentiation was likely the result of defective LAT-PLCγ1 signaling in the periphery. In addition, B cells were required for spontaneous development of Tfh cells and uncontrolled T cell expansion in these mice. Together, these results indicated a novel role for tonic LAT-PLCγ1 signaling in modulating Tfh cell differentiation during development of autoimmune syndrome.
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Affiliation(s)
- Sarah A O'Brien
- Department of Immunology, Duke University Medical Center, Durham, NC, United States
| | - Minghua Zhu
- Department of Immunology, Duke University Medical Center, Durham, NC, United States
| | - Weiguo Zhang
- Department of Immunology, Duke University Medical Center, Durham, NC, United States.,Suzhou Institute of Systems Medicine, Chinese Academy of Medical Sciences, Suzhou, China
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Zhu JJ, Stenfeldt C, Bishop EA, Canter JA, Eschbaumer M, Rodriguez LL, Arzt J. Mechanisms of Maintenance of Foot-and-Mouth Disease Virus Persistence Inferred From Genes Differentially Expressed in Nasopharyngeal Epithelia of Virus Carriers and Non-carriers. Front Vet Sci 2020; 7:340. [PMID: 32637426 PMCID: PMC7318773 DOI: 10.3389/fvets.2020.00340] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 05/15/2020] [Indexed: 12/13/2022] Open
Abstract
Foot-and-mouth disease virus (FMDV) causes persistent infection of nasopharyngeal epithelial cells in ~50% of infected ruminants. The mechanisms involved are not clear. This study provides a continued investigation of differentially expressed genes (DEG) identified in a previously published transcriptomic study analyzing micro-dissected epithelial samples from FMDV carriers and non-carriers. Pathway analysis of DEG indicated that immune cell trafficking, cell death and hematological system could be affected by the differential gene expression. Further examination of the DEG identified five downregulated (chemerin, CCL23, CXCL15, CXCL16, and CXCL17) and one upregulated (CCL2) chemokines in carriers compared to non-carriers. The differential expression could reduce the recruitment of neutrophils, antigen-experienced T cells and dendritic cells and increase the migration of macrophages and NK cells to the epithelia in carriers, which was supported by DEG expressed in these immune cells. Downregulated chemokine expression could be mainly due to the inhibition of canonical NFκB signaling based on DEG in the signaling pathways and transcription factor binding sites predicted from the proximal promoters. Additionally, upregulated CD69, IL33, and NID1 and downregulated CASP3, IL17RA, NCR3LG1, TP53BP1, TRAF3, and TRAF6 in carriers could inhibit the Th17 response, NK cell cytotoxicity and apoptosis. Based on our findings, we hypothesize that (1) under-expression of chemokines that recruit neutrophils, antigen-experienced T cells and dendritic cells, (2) blocking NK cell binding to target cells and (3) suppression of apoptosis induced by death receptor signaling, viral RNA, and cell-mediated cytotoxicity in the epithelia compromised virus clearance and allowed FMDV to persist. These hypothesized mechanisms provide novel information for further investigation of persistent FMDV infection.
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Affiliation(s)
- James J Zhu
- USDA-ARS, Foreign Animal Disease Research Unit, Plum Island Animal Disease Center, Orient, NY, United States
| | - Carolina Stenfeldt
- USDA-ARS, Foreign Animal Disease Research Unit, Plum Island Animal Disease Center, Orient, NY, United States.,Department of Diagnostic Medicine/Pathobiology, Kansas State University, Manhattan, KS, United States
| | - Elizabeth A Bishop
- USDA-ARS, Foreign Animal Disease Research Unit, Plum Island Animal Disease Center, Orient, NY, United States
| | - Jessica A Canter
- USDA-ARS, Foreign Animal Disease Research Unit, Plum Island Animal Disease Center, Orient, NY, United States.,Plum Island Animal Disease Center, Oak Ridge Institute for Science and Education (ORISE), Orient, NY, United States
| | - Michael Eschbaumer
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Greifswald, Germany
| | - Luis L Rodriguez
- USDA-ARS, Foreign Animal Disease Research Unit, Plum Island Animal Disease Center, Orient, NY, United States
| | - Jonathan Arzt
- USDA-ARS, Foreign Animal Disease Research Unit, Plum Island Animal Disease Center, Orient, NY, United States
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Yablonski D. Bridging the Gap: Modulatory Roles of the Grb2-Family Adaptor, Gads, in Cellular and Allergic Immune Responses. Front Immunol 2019; 10:1704. [PMID: 31402911 PMCID: PMC6669380 DOI: 10.3389/fimmu.2019.01704] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 07/08/2019] [Indexed: 01/07/2023] Open
Abstract
Antigen receptor signaling pathways are organized by adaptor proteins. Three adaptors, LAT, Gads, and SLP-76, form a heterotrimeric complex that mediates signaling by the T cell antigen receptor (TCR) and by the mast cell high affinity receptor for IgE (FcεRI). In both pathways, antigen recognition triggers tyrosine phosphorylation of LAT and SLP-76. The recruitment of SLP-76 to phospho-LAT is bridged by Gads, a Grb2 family adaptor composed of two SH3 domains flanking a central SH2 domain and an unstructured linker region. The LAT-Gads-SLP-76 complex is further incorporated into larger microclusters that mediate antigen receptor signaling. Gads is positively regulated by dimerization, which promotes its cooperative binding to LAT. Negative regulation occurs via phosphorylation or caspase-mediated cleavage of the linker region of Gads. FcεRI-mediated mast cell activation is profoundly impaired in LAT- Gads- or SLP-76-deficient mice. Unexpectedly, the thymic developmental phenotype of Gads-deficient mice is much milder than the phenotype of LAT- or SLP-76-deficient mice. This distinction suggests that Gads is not absolutely required for TCR signaling, but may modulate its sensitivity, or regulate a particular branch of the TCR signaling pathway; indeed, the phenotypic similarity of Gads- and Itk-deficient mice suggests a functional connection between Gads and Itk. Additional Gads binding partners include costimulatory proteins such as CD28 and CD6, adaptors such as Shc, ubiquitin regulatory proteins such as USP8 and AMSH, and kinases such as HPK1 and BCR-ABL, but the functional implications of these interactions are not yet fully understood. No interacting proteins or function have been ascribed to the evolutionarily conserved N-terminal SH3 of Gads. Here we explore the biochemical and functional properties of Gads, and its role in regulating allergy, T cell development and T-cell mediated immunity.
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Affiliation(s)
- Deborah Yablonski
- The Immune Cell Signaling Lab, Department of Immunology, Ruth and Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
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9
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Yablonski D. Bridging the Gap: Modulatory Roles of the Grb2-Family Adaptor, Gads, in Cellular and Allergic Immune Responses. Front Immunol 2019; 10:1704. [PMID: 31402911 DOI: 10.3389/fimmu.2019.01704/full] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 07/08/2019] [Indexed: 05/22/2023] Open
Abstract
Antigen receptor signaling pathways are organized by adaptor proteins. Three adaptors, LAT, Gads, and SLP-76, form a heterotrimeric complex that mediates signaling by the T cell antigen receptor (TCR) and by the mast cell high affinity receptor for IgE (FcεRI). In both pathways, antigen recognition triggers tyrosine phosphorylation of LAT and SLP-76. The recruitment of SLP-76 to phospho-LAT is bridged by Gads, a Grb2 family adaptor composed of two SH3 domains flanking a central SH2 domain and an unstructured linker region. The LAT-Gads-SLP-76 complex is further incorporated into larger microclusters that mediate antigen receptor signaling. Gads is positively regulated by dimerization, which promotes its cooperative binding to LAT. Negative regulation occurs via phosphorylation or caspase-mediated cleavage of the linker region of Gads. FcεRI-mediated mast cell activation is profoundly impaired in LAT- Gads- or SLP-76-deficient mice. Unexpectedly, the thymic developmental phenotype of Gads-deficient mice is much milder than the phenotype of LAT- or SLP-76-deficient mice. This distinction suggests that Gads is not absolutely required for TCR signaling, but may modulate its sensitivity, or regulate a particular branch of the TCR signaling pathway; indeed, the phenotypic similarity of Gads- and Itk-deficient mice suggests a functional connection between Gads and Itk. Additional Gads binding partners include costimulatory proteins such as CD28 and CD6, adaptors such as Shc, ubiquitin regulatory proteins such as USP8 and AMSH, and kinases such as HPK1 and BCR-ABL, but the functional implications of these interactions are not yet fully understood. No interacting proteins or function have been ascribed to the evolutionarily conserved N-terminal SH3 of Gads. Here we explore the biochemical and functional properties of Gads, and its role in regulating allergy, T cell development and T-cell mediated immunity.
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Affiliation(s)
- Deborah Yablonski
- The Immune Cell Signaling Lab, Department of Immunology, Ruth and Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
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10
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Ditlev JA, Case LB, Rosen MK. Who's In and Who's Out-Compositional Control of Biomolecular Condensates. J Mol Biol 2018; 430:4666-4684. [PMID: 30099028 PMCID: PMC6204295 DOI: 10.1016/j.jmb.2018.08.003] [Citation(s) in RCA: 191] [Impact Index Per Article: 31.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Revised: 08/01/2018] [Accepted: 08/05/2018] [Indexed: 02/06/2023]
Abstract
Biomolecular condensates are two- and three-dimensional compartments in eukaryotic cells that concentrate specific collections of molecules without an encapsulating membrane. Many condensates behave as dynamic liquids and appear to form through liquid-liquid phase separation driven by weak, multivalent interactions between macromolecules. In this review, we discuss current models and data regarding the control of condensate composition, and we describe our current understanding of the composition of representative condensates including PML nuclear bodies, P-bodies, stress granules, the nucleolus, and two-dimensional membrane localized LAT and nephrin clusters. Specific interactions, such as interactions between modular binding domains, weaker interactions between intrinsically disorder regions and nucleic acid base pairing, and nonspecific interactions, such as electrostatic interactions and hydrophobic interactions, influence condensate composition. Understanding how specific condensate composition is determined is essential to understanding condensates as biochemical entities and ultimately discerning their cellular and organismic functions.
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Affiliation(s)
- Jonathon A Ditlev
- Department of Biophysics and Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
| | - Lindsay B Case
- Department of Biophysics and Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
| | - Michael K Rosen
- Department of Biophysics and Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
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Milam AAV, Bartleson JM, Donermeyer DL, Horvath S, Durai V, Raju S, Yu H, Redmann V, Zinselmeyer B, White JM, Murphy KM, Allen PM. Tuning T Cell Signaling Sensitivity Alters the Behavior of CD4 + T Cells during an Immune Response. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2018; 200:3429-3437. [PMID: 29618523 PMCID: PMC5940509 DOI: 10.4049/jimmunol.1701422] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Accepted: 03/13/2018] [Indexed: 11/19/2022]
Abstract
Intricate processes in the thymus and periphery help curb the development and activation of autoreactive T cells. The subtle signals that govern these processes are an area of great interest, but tuning TCR sensitivity for the purpose of affecting T cell behavior remains technically challenging. Previously, our laboratory described the derivation of two TCR-transgenic CD4 T cell mouse lines, LLO56 and LLO118, which recognize the same cognate Listeria epitope with the same affinity. Despite the similarity of the two TCRs, LLO56 cells respond poorly in a primary infection whereas LLO118 cells respond robustly. Phenotypic examination of both lines revealed a substantial difference in their surface of expression of CD5, which serves as a dependable readout of the self-reactivity of a cell. We hypothesized that the increased interaction with self by the CD5-high LLO56 was mediated through TCR signaling, and was involved in the characteristic weak primary response of LLO56 to infection. To explore this issue, we generated an inducible knock-in mouse expressing the self-sensitizing voltage-gated sodium channel Scn5a. Overexpression of Scn5a in peripheral T cells via the CD4-Cre promoter resulted in increased TCR-proximal signaling. Further, Scn5a-expressing LLO118 cells, after transfer into BL6 recipient mice, displayed an impaired response during infection relative to wild-type LLO118 cells. In this way, we were able to demonstrate that tuning of TCR sensitivity to self can be used to alter in vivo immune responses. Overall, these studies highlight the critical relationship between TCR-self-pMHC interaction and an immune response to infection.
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Affiliation(s)
- Ashley A Viehmann Milam
- Division of Immunobiology, Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110
| | - Juliet M Bartleson
- Division of Immunobiology, Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110
| | - David L Donermeyer
- Division of Immunobiology, Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110
| | - Stephen Horvath
- Division of Immunobiology, Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110
| | - Vivek Durai
- Division of Immunobiology, Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110
| | - Saravanan Raju
- Division of Immunobiology, Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110
| | - Haiyang Yu
- Ludwig Institute for Cancer Research, La Jolla, CA 92093; and
| | - Veronika Redmann
- Division of Immunobiology, Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110
| | - Bernd Zinselmeyer
- Division of Immunobiology, Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110
| | - J Michael White
- Division of Immunobiology, Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110
| | - Kenneth M Murphy
- Division of Immunobiology, Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110
- Howard Hughes Medical Institute, Washington University School of Medicine, St. Louis, MO 63110
| | - Paul M Allen
- Division of Immunobiology, Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110;
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Min B. Spontaneous T Cell Proliferation: A Physiologic Process to Create and Maintain Homeostatic Balance and Diversity of the Immune System. Front Immunol 2018; 9:547. [PMID: 29616038 PMCID: PMC5868360 DOI: 10.3389/fimmu.2018.00547] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2018] [Accepted: 03/05/2018] [Indexed: 11/14/2022] Open
Abstract
Naive T lymphocytes undergo heterogeneous proliferative responses when introduced into lymphopenic hosts, referred to as “homeostatic proliferation” and “spontaneous proliferation.” Spontaneous proliferation is a unique process through which the immune system generates memory phenotype cells with increasing T cell receptors repertoire complexity. Here, the mechanisms that initiate and control spontaneous proliferation are discussed.
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Affiliation(s)
- Booki Min
- Department of Immunology, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, United States
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13
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Clearance of a persistent picornavirus infection is associated with enhanced pro-apoptotic and cellular immune responses. Sci Rep 2017; 7:17800. [PMID: 29259271 PMCID: PMC5736604 DOI: 10.1038/s41598-017-18112-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Accepted: 12/04/2017] [Indexed: 12/22/2022] Open
Abstract
Long-term persistent viral infections cause substantial morbidity and associated economic losses in human and veterinary contexts. Yet, the mechanisms associated with establishment of persistent infections are poorly elucidated. We investigated immunomodulatory mechanisms associated with clearance versus persistence of foot-and-mouth disease virus (FMDV) in micro-dissected compartments of the bovine nasopharynx by microarray. The use of laser-capture microdissection allowed elucidation of differential gene regulation within distinct anatomic compartments critical to FMDV infection. Analysis of samples from transitional and persistent phases of infection demonstrated significant differences in transcriptome profiles of animals that cleared infection versus those that became persistently infected carriers. Specifically, it was demonstrated that clearance of FMDV from the nasopharyngeal mucosa was associated with upregulation of targets associated with activation of T cell-mediated immunity. Contrastingly, gene regulation in FMDV carriers suggested inhibition of T cell activation and promotion of Th2 polarization. These findings were corroborated by immunofluorescence microscopy which demonstrated relative abundance of CD8+ T cells in the nasopharyngeal mucosa in association with clearance of FMDV. The findings presented herein emphasize that a critical balance between Th1 and Th2 -mediated immunity is essential for successful clearance of FMDV infection and should be considered for development of next-generation vaccines and antiviral products.
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14
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Myers DR, Lau T, Markegard E, Lim HW, Kasler H, Zhu M, Barczak A, Huizar JP, Zikherman J, Erle DJ, Zhang W, Verdin E, Roose JP. Tonic LAT-HDAC7 Signals Sustain Nur77 and Irf4 Expression to Tune Naive CD4 T Cells. Cell Rep 2017; 19:1558-1571. [PMID: 28538176 PMCID: PMC5587137 DOI: 10.1016/j.celrep.2017.04.076] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Revised: 04/05/2017] [Accepted: 04/27/2017] [Indexed: 12/20/2022] Open
Abstract
CD4+ T cells differentiate into T helper cell subsets in feedforward manners with synergistic signals from the T cell receptor (TCR), cytokines, and lineage-specific transcription factors. Naive CD4+ T cells avoid spontaneous engagement of feedforward mechanisms but retain a prepared state. T cells lacking the adaptor molecule LAT demonstrate impaired TCR-induced signals yet cause a spontaneous lymphoproliferative T helper 2 (TH2) cell syndrome in mice. Thus, LAT constitutes an unexplained maintenance cue. Here, we demonstrate that tonic signals through LAT constitutively export the repressor HDAC7 from the nucleus of CD4+ T cells. Without such tonic signals, HDAC7 target genes Nur77 and Irf4 are repressed. We reveal that Nur77 suppresses CD4+ T cell proliferation and uncover a suppressive role for Irf4 in TH2 polarization; halving Irf4 gene-dosage leads to increases in GATA3+ and IL-4+ cells. Our studies reveal that naive CD4+ T cells are dynamically tuned by tonic LAT-HDAC7 signals.
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Affiliation(s)
- Darienne R Myers
- Department of Anatomy, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Tannia Lau
- Department of Anatomy, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Evan Markegard
- Department of Anatomy, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Hyung W Lim
- Gladstone Institute of Virology and Immunology, University of California, San Francisco, 1650 Owens Street, San Francisco, CA 94158, USA
| | - Herbert Kasler
- Gladstone Institute of Virology and Immunology, University of California, San Francisco, 1650 Owens Street, San Francisco, CA 94158, USA
| | - Minghua Zhu
- Department of Immunology, Duke University Medical Center, Durham, NC 27710, USA
| | - Andrea Barczak
- Lung Biology Center, Department of Medicine, University of California, San Francisco, San Francisco, CA 94143, USA
| | - John P Huizar
- Division of Rheumatology, Rosalind Russell and Ephraim P. Engleman Arthritis Research Center, Department of Medicine, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Julie Zikherman
- Division of Rheumatology, Rosalind Russell and Ephraim P. Engleman Arthritis Research Center, Department of Medicine, University of California, San Francisco, San Francisco, CA 94143, USA
| | - David J Erle
- Lung Biology Center, Department of Medicine, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Weiguo Zhang
- Department of Immunology, Duke University Medical Center, Durham, NC 27710, USA
| | - Eric Verdin
- Gladstone Institute of Virology and Immunology, University of California, San Francisco, 1650 Owens Street, San Francisco, CA 94158, USA
| | - Jeroen P Roose
- Department of Anatomy, University of California, San Francisco, San Francisco, CA 94143, USA.
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15
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Siegmund K, Thuille N, Wachowicz K, Hermann-Kleiter N, Baier G. Protein kinase C theta is dispensable for suppression mediated by CD25+CD4+ regulatory T cells. PLoS One 2017; 12:e0175463. [PMID: 28531229 PMCID: PMC5439664 DOI: 10.1371/journal.pone.0175463] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Accepted: 03/27/2017] [Indexed: 12/24/2022] Open
Abstract
The activation of conventional T cells upon T cell receptor stimulation critically depends on protein kinase C theta (PKCθ). However, its role in regulatory T (Treg) cell function has yet to be fully elucidated. Using siRNA or the potent and PKC family-selective pharmacological inhibitor AEB071, we could show that murine Treg-mediated suppression in vitro is independent of PKCθ function. Likewise, Treg cells of PKCθ-deficient mice were fully functional, showing a similar suppressive activity as wild-type CD25+CD4+ T cells in an in vitro suppression assay. Furthermore, in vitro-differentiated wild-type and PKCθ-deficient iTreg cells showed comparable Foxp3 expression as well as suppressive activity. However, we observed a reduced percentage of Foxp3+CD25+ CD4+ T cells in the lymphatic organs of PKCθ-deficient mice. Taken together, our results suggest that while PKCθ is involved in Treg cell differentiation in vivo, it is dispensable for Treg-mediated suppression.
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Affiliation(s)
- Kerstin Siegmund
- Department for Pharmacology and Genetics, Medical University Innsbruck, Innsbruck, Austria
- * E-mail: (GB); (KS)
| | - Nikolaus Thuille
- Department for Pharmacology and Genetics, Medical University Innsbruck, Innsbruck, Austria
| | - Katarzyna Wachowicz
- Department for Pharmacology and Genetics, Medical University Innsbruck, Innsbruck, Austria
| | | | - Gottfried Baier
- Department for Pharmacology and Genetics, Medical University Innsbruck, Innsbruck, Austria
- * E-mail: (GB); (KS)
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16
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Pedros C, Duguet F, Saoudi A, Chabod M. Disrupted regulatory T cell homeostasis in inflammatory bowel diseases. World J Gastroenterol 2016; 22:974-995. [PMID: 26811641 PMCID: PMC4716049 DOI: 10.3748/wjg.v22.i3.974] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Revised: 10/02/2015] [Accepted: 11/19/2015] [Indexed: 02/06/2023] Open
Abstract
In the gut, where billions of non-self-antigens from the food and the microbiota are present, the immune response must be tightly regulated to ensure both host protection against pathogenic microorganisms and the absence of immune-related pathologies. It has been well documented that regulatory T cells (Tregs) play a pivotal role in this context. Indeed, Tregs are able to prevent excessive inflammation, which can lead to the rupture of intestinal homeostasis observed in inflammatory bowel diseases (IBDs). Both the worldwide incidence and prevalence of such diseases have increased throughout the latter part of the 20th century. Therefore, it is crucial to understand how Tregs suppress the colitogenic immune cells to establish new treatments for patients suffering from IBDs. In this review, we will first summarize the results obtained in animal model studies that highlight the importance of Tregs in maintaining intestinal homeostasis and describe the specific suppressive mechanisms involved. Next, our current knowledge about Tregs contribution to human IBDs will be reviewed, as well as the current therapeutic perspective on using Tregs for clinical IBD treatment and the challenges that remain to be resolved to ensure both the safety and effectiveness of these therapies in targeting this critical immune-regulatory cell population.
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17
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Zhang B, Wu J, Jiao Y, Bock C, Dai M, Chen B, Chao N, Zhang W, Zhuang Y. Differential Requirements of TCR Signaling in Homeostatic Maintenance and Function of Dendritic Epidermal T Cells. THE JOURNAL OF IMMUNOLOGY 2015; 195:4282-91. [PMID: 26408667 DOI: 10.4049/jimmunol.1501220] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Accepted: 09/01/2015] [Indexed: 01/17/2023]
Abstract
Dendritic epidermal T cells (DETCs) are generated exclusively in the fetal thymus and maintained in the skin epithelium throughout postnatal life of the mouse. DETCs have restricted antigenic specificity as a result of their exclusive usage of a canonical TCR. Although the importance of the TCR in DETC development has been well established, the exact role of TCR signaling in DETC homeostasis and function remains incompletely defined. In this study, we investigated TCR signaling in fully matured DETCs by lineage-restricted deletion of the Lat gene, an essential signaling molecule downstream of the TCR. We found that Lat deletion impaired TCR-dependent cytokine gene activation and the ability of DETCs to undergo proliferative expansion. However, linker for activation of T cells-deficient DETCs were able to maintain long-term population homeostasis, although with a reduced proliferation rate. Mice with Lat deletion in DETCs exhibited delayed wound healing accompanied by impaired clonal expansion within the wound area. Our study revealed differential requirements for TCR signaling in homeostatic maintenance of DETCs and in their effector function during wound healing.
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Affiliation(s)
- Baojun Zhang
- Department of Immunology, Duke University Medical Center, Durham, NC 27710
| | - Jianxuan Wu
- Department of Immunology, Duke University Medical Center, Durham, NC 27710
| | - Yiqun Jiao
- Department of Medicine, Duke University Medical Center, Durham, NC 27710; and
| | - Cheryl Bock
- Duke Cancer Institute, Duke University Medical Center, Durham, NC 27710
| | - Meifang Dai
- Department of Immunology, Duke University Medical Center, Durham, NC 27710
| | - Benny Chen
- Department of Medicine, Duke University Medical Center, Durham, NC 27710; and
| | - Nelson Chao
- Department of Immunology, Duke University Medical Center, Durham, NC 27710; Department of Medicine, Duke University Medical Center, Durham, NC 27710; and Duke Cancer Institute, Duke University Medical Center, Durham, NC 27710
| | - Weiguo Zhang
- Department of Immunology, Duke University Medical Center, Durham, NC 27710; Duke Cancer Institute, Duke University Medical Center, Durham, NC 27710
| | - Yuan Zhuang
- Department of Immunology, Duke University Medical Center, Durham, NC 27710; Duke Cancer Institute, Duke University Medical Center, Durham, NC 27710
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18
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Balagopalan L, Kortum RL, Coussens NP, Barr VA, Samelson LE. The linker for activation of T cells (LAT) signaling hub: from signaling complexes to microclusters. J Biol Chem 2015; 290:26422-9. [PMID: 26354432 DOI: 10.1074/jbc.r115.665869] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Since the cloning of the critical adapter, LAT (linker for activation of T cells), more than 15 years ago, a combination of multiple scientific approaches and techniques continues to provide valuable insights into the formation, composition, regulation, dynamics, and function of LAT-based signaling complexes. In this review, we will summarize current views on the assembly of signaling complexes nucleated by LAT. LAT forms numerous interactions with other signaling molecules, leading to cooperativity in the system. Furthermore, oligomerization of LAT by adapter complexes enhances intracellular signaling and is physiologically relevant. These results will be related to data from super-resolution microscopy studies that have revealed the smallest LAT-based signaling units and nanostructure.
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Affiliation(s)
- Lakshmi Balagopalan
- From the Laboratory of Cellular and Molecular Biology, Center for Cancer Research, NCI, National Institutes of Health, Bethesda, Maryland 20892-4256
| | - Robert L Kortum
- the Department of Pharmacology, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814, and
| | - Nathan P Coussens
- the Division of Pre-Clinical Innovation, National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland 20850
| | - Valarie A Barr
- From the Laboratory of Cellular and Molecular Biology, Center for Cancer Research, NCI, National Institutes of Health, Bethesda, Maryland 20892-4256
| | - Lawrence E Samelson
- From the Laboratory of Cellular and Molecular Biology, Center for Cancer Research, NCI, National Institutes of Health, Bethesda, Maryland 20892-4256,
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19
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Abstract
Induction of specific immune tolerance to grafts remains the sought-after standard following transplantation. Defined by expression of the Foxp3 (forkhead box protein 3) transcription factor, the regulatory T-cell (Treg) lineage has been noted to exert potent immunoregulatory functions that contribute to specific graft tolerance. In this review, we discuss the known signals and pathways which govern Treg development, both in the thymus and in peripheral sites, as well as lineage maintenance and homeostasis. In particular, we highlight the roles of T-cell receptor signaling, CD28 costimulation, and signals through phosphatidyl inositol 3-kinase (PI3K) and related metabolic pathways in multiple aspects of Treg biology.
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Affiliation(s)
- Alexandria Huynh
- Division of Medical Sciences, Harvard Medical School, Boston, MA, USA; Transplantation Biology Research Center, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
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20
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Zhou GF, Liu QT, Zhou B, Qiu YF, Liu XD, Ma ZY, Feng XL, Cao RB, Chen PY. The potential molecular effects of bursal septpeptide II on immune induction and antitumor activity. J Vet Sci 2015; 16:325-31. [PMID: 25643804 PMCID: PMC4588018 DOI: 10.4142/jvs.2015.16.3.325] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Accepted: 01/29/2015] [Indexed: 11/30/2022] Open
Abstract
The bursa of Fabricius (BF) is the acknowledged central humoral immune organ in birds. Bursal septpeptide II (BSP-II) is an immunomodulatory bioactive peptide isolated from BF. To understand the effects of BSP-II on immune induction, gene expression profiles of hybridoma cells treated with BSP-II were evaluated. Pathway analysis showed that regulated genes were involved in cytokine-cytokine receptor interactions, T cell receptor signaling pathway, and pathway in cancer. It was observed that BSP-II reduced tumor cells proliferation and stimulated p53 expression. These results indicate potential mechanisms underlying the effects of the humoral immune system on immune induction, including antitumor activities. Our study has provided a novel insight into immunotherapeutic strategies for treating human tumors.
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Affiliation(s)
- Guang Fang Zhou
- Division of Key Lab of Animal Disease Diagnosis and Immunology of China's Department of Agriculture, College of Veterinary Medicine, Nanjing Agriculture University, Nanjing 210095, China
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21
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Paster W, Bruger AM, Katsch K, Grégoire C, Roncagalli R, Fu G, Gascoigne NRJ, Nika K, Cohnen A, Feller SM, Simister PC, Molder KC, Cordoba SP, Dushek O, Malissen B, Acuto O. A THEMIS:SHP1 complex promotes T-cell survival. EMBO J 2014; 34:393-409. [PMID: 25535246 PMCID: PMC4339124 DOI: 10.15252/embj.201387725] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
THEMIS is critical for conventional T-cell development, but its precise molecular function remains elusive. Here, we show that THEMIS constitutively associates with the phosphatases SHP1 and SHP2. This complex requires the adapter GRB2, which bridges SHP to THEMIS in a Tyr-phosphorylation-independent fashion. Rather, SHP1 and THEMIS engage with the N-SH3 and C-SH3 domains of GRB2, respectively, a configuration that allows GRB2-SH2 to recruit the complex onto LAT. Consistent with THEMIS-mediated recruitment of SHP to the TCR signalosome, THEMIS knock-down increased TCR-induced CD3-ζ phosphorylation, Erk activation and CD69 expression, but not LCK phosphorylation. This generalized TCR signalling increase led to augmented apoptosis, a phenotype mirrored by SHP1 knock-down. Remarkably, a KI mutation of LCK Ser59, previously suggested to be key in ERK-mediated resistance towards SHP1 negative feedback, did not affect TCR signalling nor ligand discrimination in vivo. Thus, the THEMIS:SHP complex dampens early TCR signalling by a previously unknown molecular mechanism that favours T-cell survival. We discuss possible implications of this mechanism in modulating TCR output signals towards conventional T-cell development and differentiation.
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Affiliation(s)
- Wolfgang Paster
- T Cell Signalling Laboratory, Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Annika M Bruger
- T Cell Signalling Laboratory, Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Kristin Katsch
- T Cell Signalling Laboratory, Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Claude Grégoire
- Centre d'Immunologie de Marseille-Luminy, UM2 Aix-Marseille Université, Marseille, France INSERM U1104, Marseille, France CNRS UMR7280, Marseille, France
| | - Romain Roncagalli
- Centre d'Immunologie de Marseille-Luminy, UM2 Aix-Marseille Université, Marseille, France INSERM U1104, Marseille, France CNRS UMR7280, Marseille, France
| | - Guo Fu
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, CA, USA
| | - Nicholas R J Gascoigne
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, CA, USA Department of Microbiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Konstantina Nika
- T Cell Signalling Laboratory, Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Andre Cohnen
- T Cell Signalling Laboratory, Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Stephan M Feller
- Biological Systems Architecture Group, Department of Oncology, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK Tumor Biology Unit, Institute of Molecular Medicine, ZAMED, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Philip C Simister
- Biological Systems Architecture Group, Department of Oncology, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - Kelly C Molder
- T Cell Signalling Laboratory, Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Shaun-Paul Cordoba
- Molecular Immunology Group, Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Omer Dushek
- Molecular Immunology Group, Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Bernard Malissen
- Centre d'Immunologie de Marseille-Luminy, UM2 Aix-Marseille Université, Marseille, France INSERM U1104, Marseille, France CNRS UMR7280, Marseille, France
| | - Oreste Acuto
- T Cell Signalling Laboratory, Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
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22
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Abstract
Regulatory T (TReg) cells constitute an essential counterbalance to adaptive immune responses. Failure to maintain appropriate TReg cell numbers or function leads to autoimmune, malignant and immunodeficient conditions. Dynamic homeostatic processes preserve the number of forkhead box P3-expressing (FOXP3(+)) TReg cells within a healthy range, with high rates of cell division being offset by apoptosis under steady-state conditions. Recent studies have shown that TReg cells become specialized for different environmental contexts, tailoring their functions and homeostatic properties to a wide range of tissues and immune conditions. In this Review, we describe new insights into the molecular controls that maintain the steady-state homeostasis of TReg cells and the cues that drive TReg cell adaptation to inflammation and/or different locations. We highlight how differing local milieu might drive context-specific TReg cell function and restoration of immune homeostasis, and how dysregulation of these processes can precipitate disease.
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Affiliation(s)
- Adrian Liston
- 1] Autoimmune Genetics Laboratory, VIB, Leuven 3000, Belgium. [2] Department of Microbiology and Immunology, University of Leuven, Leuven 3000, Belgium
| | - Daniel H D Gray
- 1] The Walter and Eliza Hall Institute of Medical Research, Melbourne 3053, Australia. [2] Department of Medical Biology, University of Melbourne, Melbourne 3052, Australia
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23
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Deng W, Geng Z, Li H. LEARNING LOCAL DIRECTED ACYCLIC GRAPHS BASED ON MULTIVARIATE TIME SERIES DATA. Ann Appl Stat 2014; 7:1249-1835. [PMID: 24465291 DOI: 10.1214/13-aoas635] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Multivariate time series (MTS) data such as time course gene expression data in genomics are often collected to study the dynamic nature of the systems. These data provide important information about the causal dependency among a set of random variables. In this paper, we introduce a computationally efficient algorithm to learn directed acyclic graphs (DAGs) based on MTS data, focusing on learning the local structure of a given target variable. Our algorithm is based on learning all parents (P), all children (C) and some descendants (D) (PCD) iteratively, utilizing the time order of the variables to orient the edges. This time series PCD-PCD algorithm (tsPCD-PCD) extends the previous PCD-PCD algorithm to dependent observations and utilizes composite likelihood ratio tests (CLRTs) for testing the conditional independence. We present the asymptotic distribution of the CLRT statistic and show that the tsPCD-PCD is guaranteed to recover the true DAG structure when the faithfulness condition holds and the tests correctly reject the null hypotheses. Simulation studies show that the CLRTs are valid and perform well even when the sample sizes are small. In addition, the tsPCD-PCD algorithm outperforms the PCD-PCD algorithm in recovering the local graph structures. We illustrate the algorithm by analyzing a time course gene expression data related to mouse T-cell activation.
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Affiliation(s)
- Wanlu Deng
- Department of Statistics and Probability, Peking University, Beijing 100871, PR China. Department of Biostatistics, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
| | - Zhi Geng
- Department of Statistics and Probability, Peking University, Beijing 100871, PR China. Department of Biostatistics, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
| | - Hongzhe Li
- Department of Statistics and Probability, Peking University, Beijing 100871, PR China. Department of Biostatistics, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
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24
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Satake A, Schmidt AM, Archambault A, Leichner TM, Wu GF, Kambayashi T. Differential targeting of IL-2 and T cell receptor signaling pathways selectively expands regulatory T cells while inhibiting conventional T cells. J Autoimmun 2013; 44:13-20. [PMID: 23834842 DOI: 10.1016/j.jaut.2013.06.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2013] [Revised: 06/17/2013] [Accepted: 06/18/2013] [Indexed: 12/19/2022]
Abstract
Strategies to expand regulatory T cells hold therapeutic potential for ameliorating T cell-mediated autoimmunity. Recently, we reported that the requirements for T cell receptor signaling in conventional T cell and regulatory T cell proliferation are different. Using mutant mice that display defective T cell receptor-mediated phospholipase Cγ (PLCγ) activation, we hereby demonstrate that PLCγ activation is required for antigen-specific conventional T cell proliferation but not for IL-2-induced regulatory T cell proliferation. This led us to hypothesize that in conjunction with IL-2, pharmacological inhibition of T cell receptor-mediated PLCγ activation might offer a novel therapeutic strategy to expand regulatory T cells while simultaneously inhibiting conventional T cell proliferation. Indeed, using the calcineurin inhibitor Cyclosporine A to inhibit signaling downstream of PLCγ, we found that Cyclosporine A attenuated antigen-specific Tconv proliferation but permitted IL-2-induced regulatory T cell expansion in vitro and in vivo. Furthermore, the combination of Cyclosporine A and IL-2 was superior over either Cyclosporine A or IL-2 monotherapy in protection against the T cell-mediated demyelinating autoimmune disease mouse model, experimental autoimmune encephalomyelitis. Thus, a combination of TCR signaling inhibition and IL-2 might be a beneficial strategy in expanding regulatory T cells and inhibiting conventional T cell proliferation in autoimmune settings.
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Affiliation(s)
- Atsushi Satake
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine at The University of Pennsylvania, Philadelphia, PA 10194, USA
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25
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Ou-Yang CW, Zhu M, Sullivan SA, Fuller DM, Zhang W. The requirement of linker for activation of T cells in the primary and memory responses of CD8 T cells. THE JOURNAL OF IMMUNOLOGY 2013; 190:2938-47. [PMID: 23401587 DOI: 10.4049/jimmunol.1203163] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Linker for activation of T cells (LAT) is a transmembrane adaptor protein that links TCR engagement to downstream signaling events. Although it is clear that LAT is essential in thymocyte development and initiation of T cell activation, its function during T cell expansion, contraction, and memory formation remains unknown. To study the role of TCR-mediated signaling in CD8 T cells during the course of pathogen infection, we used an inducible mouse model to delete LAT in Ag-specific CD8 T cells at different stages of Listeria infection and analyzed the effect of deletion on T cell responses. Our data showed that LAT is important for maintaining CD8 T cell expansion during the priming phase; however, it is not required for CD8 T cell contraction and memory maintenance. Moreover, LAT deficiency accelerates memory differentiation during the effector-to-memory transition, leading to a higher frequency of KLRG1(low)IL-7R(high)CD62L(high) memory T cells. Nonetheless, these LAT-deficient memory T cells were unable to proliferate or produce cytokines upon secondary infection. Our data demonstrated that, although TCR-mediated signaling is dispensable for contraction and memory maintenance, it regulates CD8 T cell memory differentiation and is essential for the memory response against pathogens.
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Affiliation(s)
- Chih-wen Ou-Yang
- Department of Immunology, Duke University Medical Center, Durham, NC 27710, USA
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26
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Kunii N, Zhao Y, Jiang S, Liu X, Scholler J, Balagopalan L, Samelson LE, Milone MC, June CH. Enhanced function of redirected human T cells expressing linker for activation of T cells that is resistant to ubiquitylation. Hum Gene Ther 2013; 24:27-37. [PMID: 22998346 PMCID: PMC3555093 DOI: 10.1089/hum.2012.130] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2012] [Accepted: 09/07/2012] [Indexed: 11/13/2022] Open
Abstract
It is likely that the enhancement of signaling after antigenic stimulation, particularly in the tumor microenvironment, would improve the function of adoptively transferred T cells. Linker for activation of T cells (LAT) plays a central role in T cell activation. We hypothesized that the ubiquitylation-resistant form of LAT in cells would enhance T cell signaling and thus augment antitumor activity. To test this, human CD4(+) or CD8(+) T cells were electroporated with small interfering RNA (siRNA) to repress endogenous LAT and ubiquitylation-resistant LAT 2KR or wild-type LAT mRNA was introduced for reexpression. Significantly enhanced phosphorylation of LAT and phospholipase C-γ (PLCγ) was observed, and augmented calcium signaling after T cell receptor (TCR) triggering was observed in LAT 2KR-expressing T cells. TCR-induced calcium signaling was abrogated in LAT knockdown cells, but the baseline was higher than that of control siRNA-electroporated cells, suggesting a fundamental requirement of LAT to maintain calcium homeostasis. Redirected LAT 2KR T cells expressing a chimeric antigen receptor or an MHC class I-restricted TCR showed augmented function as assessed by enhanced cytokine secretion and cytotoxicity. These results indicate that interruption of LAT ubiquitylation is a promising strategy to augment effector T cell function for adoptive cell therapy.
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Affiliation(s)
- Naoki Kunii
- Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-5156
| | - Yangbing Zhao
- Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-5156
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-4283
| | - Shuguang Jiang
- Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-5156
| | - Xiaojun Liu
- Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-5156
| | - John Scholler
- Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-5156
| | - Lakshmi Balagopalan
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892-4256
| | - Lawrence E. Samelson
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892-4256
| | - Michael C. Milone
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-4283
| | - Carl H. June
- Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-5156
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Nguyen TM, Ravindra D, Kwong B, Waheed S, Ferguson R, Tarlton N, Wu V, Sequeira CS, Bremer M, Abramson T. Differential expression of alpha 4 integrins on effector memory T helper cells during Bordetella infections. Delayed responses in Bordetella pertussis. PLoS One 2012; 7:e52903. [PMID: 23300813 PMCID: PMC3531986 DOI: 10.1371/journal.pone.0052903] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2012] [Accepted: 11/23/2012] [Indexed: 11/18/2022] Open
Abstract
Bordetella pertussis (B. pertussis) is the causative agent of whooping cough, a respiratory disease that is reemerging worldwide. Mechanisms of selective lymphocyte trafficking to the airways are likely to be critical in the immune response to this pathogen. We compared murine infection by B. pertussis, B. parapertussis, and a pertussis toxin-deleted B. pertussis mutant (BpΔPTX) to test the hypothesis that effector memory T-helper cells (emTh) display an altered pattern of trafficking receptor expression in B. pertussis infection due to a defect in imprinting. Increased cell recruitment to the lungs at 5 days post infection (p.i.) with B. parapertussis, and to a lesser extent with BpΔPTX, coincided with an increased frequency of circulating emTh cells expressing the mucosal-associated trafficking receptors α4β7 and α4β1 while a reduced population of these cells was observed in B. pertussis infection. These cells were highly evident in the blood and lungs in B. pertussis infection only at 25 days p.i. when B. parapertussis and BpΔPTX infections were resolved. Although at 5 days p.i., an equally high percentage of lung dendritic cells (DCs) from all infections expressed maturation markers, this expression persisted only in B. pertussis infection at 25 days p.i. Furthermore, at 5 days p.i with B. pertussis, lung DCs migration to draining lymph nodes may be compromised as evidenced by decreased frequency of CCR7(+) DCs, inhibited CCR7-mediated in vitro migration, and fewer DCs in lung draining lymph nodes. Lastly, a reduced frequency of allogeneic CD4(+) cells expressing α4β1 was detected following co-culture with lung DCs from B. pertussis-infected mice, suggesting a defect in DC imprinting in comparison to the other infection groups. The findings in this study suggest that B. pertussis may interfere with imprinting of lung-associated trafficking receptors on T lymphocytes leading to extended survival in the host and a prolonged course of disease.
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Affiliation(s)
- Tuan M. Nguyen
- Department of Biology, San Jose State University, San Jose, California, United States of America
| | - Dipti Ravindra
- Department of Biology, San Jose State University, San Jose, California, United States of America
| | - Brian Kwong
- Department of Biology, San Jose State University, San Jose, California, United States of America
| | - Sana Waheed
- Department of Biology, San Jose State University, San Jose, California, United States of America
| | - Ryan Ferguson
- Department of Biology, San Jose State University, San Jose, California, United States of America
| | - Nicole Tarlton
- Department of Biology, San Jose State University, San Jose, California, United States of America
| | - Victoria Wu
- Department of Biology, San Jose State University, San Jose, California, United States of America
| | - Christopher S. Sequeira
- Department of Biology, San Jose State University, San Jose, California, United States of America
| | - Martina Bremer
- Department of Mathematics, San Jose State University, San Jose, California, United States of America
| | - Tzvia Abramson
- Department of Biology, San Jose State University, San Jose, California, United States of America
- * E-mail:
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28
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Dalotto-Moreno T, Croci DO, Cerliani JP, Martinez-Allo VC, Dergan-Dylon S, Méndez-Huergo SP, Stupirski JC, Mazal D, Osinaga E, Toscano MA, Sundblad V, Rabinovich GA, Salatino M. Targeting galectin-1 overcomes breast cancer-associated immunosuppression and prevents metastatic disease. Cancer Res 2012. [PMID: 23204230 DOI: 10.1158/0008-5472.can-12-2418] [Citation(s) in RCA: 185] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Galectin-1 (Gal1), an evolutionarily conserved glycan-binding protein, contributes to the creation of an immunosuppressed microenvironment at sites of tumor growth. In spite of considerable progress in elucidating its role in tumor-immune escape, the mechanisms underlying the inhibitory functions of Gal1 remain obscure. Here, we investigated the contribution of tumor Gal1 to tumor growth, metastasis, and immunosuppression in breast cancer. We found that the frequency of Gal1(+) cells in human breast cancer biopsies correlated positively with tumor grade, while specimens from patients with benign hyperplasia showed negative or limited Gal1 staining. To examine the pathophysiologic relevance of Gal1 in breast cancer, we used the metastatic mouse mammary tumor 4T1, which expresses and secretes substantial amounts of Gal1. Silencing Gal1 expression in this model induced a marked reduction in both tumor growth and the number of lung metastases. This effect was abrogated when mice were inoculated with wild-type 4T1 tumor cells in their contralateral flank, suggesting involvement of a systemic modulation of the immune response. Gal1 attenuation in 4T1 cells also reduced the frequency of CD4(+)CD25(+) Foxp3(+) regulatory T (T(reg)) cells within the tumor, draining lymph nodes, spleen, and lung metastases. Further, it abrogated the immunosuppressive function of T(reg) cells and selectively lowered the expression of the T-cell regulatory molecule LAT (linker for activation of T cells) on these cells, disarming their suppressive activity. Taken together, our results offer a preclinical proof of concept that therapeutic targeting of Gal1 can overcome breast cancer-associated immunosuppression and can prevent metastatic disease.
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Affiliation(s)
- Tomás Dalotto-Moreno
- Laboratorio de Inmunopatología, Instituto de Biología y Medicina Experimental (IBYME), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
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29
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Fuller DM, Zhu M, Koonpaew S, Nelson MI, Zhang W. The importance of the Erk pathway in the development of linker for activation of T cells-mediated autoimmunity. THE JOURNAL OF IMMUNOLOGY 2012; 189:4005-13. [PMID: 22984075 DOI: 10.4049/jimmunol.1201380] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The ability of the transmembrane adaptor protein linker for activation of T cells (LAT) to regulate T cell development, activation, survival, and homeostasis depends upon phosphorylation of its multiple tyrosine residues. The mutation of tyrosine 136 on LAT abrogates its interaction with phospholipase C-γ1, causing severe ramifications on TCR-mediated signaling. Mice harboring this mutation, LATY136F mice, have significantly impaired thymocyte development; however, they rapidly develop a fatal lymphoproliferative disease marked by the uncontrolled expansion of Th2-skewed CD4(+) T cells, high levels of IgE and IgG1, and autoantibody production. In this study, we assessed the contribution of multiple signaling pathways in LATY136F disease development. The deletion of the critical signaling proteins Gads and RasGRP1 caused a further block in thymocyte development, but, over time, could not prevent CD4(+) T cell hyperproliferation. Also, restoring signaling through the NF-κB and NFAT pathways was unable to halt the development of disease. However, expression of a constitutively active Raf transgene enhanced lymphoproliferation, indicating a role for the Ras-MAPK pathway in LAT-mediated disease.
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Affiliation(s)
- Deirdre M Fuller
- Department of Immunology, Duke University Medical Center, Durham, NC 27710, USA
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30
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Zou T, Satake A, Corbo-Rodgers E, Schmidt AM, Farrar MA, Maltzman JS, Kambayashi T. Cutting edge: IL-2 signals determine the degree of TCR signaling necessary to support regulatory T cell proliferation in vivo. THE JOURNAL OF IMMUNOLOGY 2012; 189:28-32. [PMID: 22623329 DOI: 10.4049/jimmunol.1200507] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
To ensure immune tolerance, regulatory T cell (Treg) numbers must be maintained by cell division. This process has been thought to be strictly dependent on the Treg TCR interacting with MHC class II. In this study, we report that Treg division does not absolutely require cell-autonomous TCR signaling in vivo, depending on the degree of IL-2-mediated stimulation provided. At steady state IL-2 levels, Tregs require cell-autonomous TCR signaling to divide. However, when given exogenous IL-2 or when STAT5 is selectively activated in Tregs, Treg division can occur independently of MHC class II and TCR signaling. Thus, depending on the amount of IL-2R stimulation, a wide range of TCR signals supports Treg division, which may contribute to preservation of a diverse repertoire of Treg TCR specificities. These findings also have therapeutic implications, as TCR signaling by Tregs may not be required when using IL-2 to increase Treg numbers for treatment of inflammatory disorders.
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Affiliation(s)
- Tao Zou
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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31
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Fuller DM, Zhu M, Ou-Yang CW, Sullivan SA, Zhang W. A tale of two TRAPs: LAT and LAB in the regulation of lymphocyte development, activation, and autoimmunity. Immunol Res 2011; 49:97-108. [PMID: 21136199 DOI: 10.1007/s12026-010-8197-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Transmembrane adaptor proteins (TRAPs) link antigen receptor engagement to downstream cellular processes. Although these proteins typically lack intrinsic enzymatic activity, they are phosphorylated on multiple tyrosine residues following lymphocyte activation, allowing them to function as scaffolds for the assembly of multi-molecular signaling complexes. Among the many TRAPs that have been discovered in recent years, the LAT (linker for activation of T cells) family of adaptor proteins plays an important role in the positive and negative regulation of lymphocyte maturation, activation, and differentiation. Of the two members in this family, LAT is an indispensable component controlling T cell and mast cell activation and function; LAB (linker for activation of B cells), also called NTAL, is necessary to fine-tune lymphocyte activation and may be a key regulator of innate immune responses. Here, we review recent advances on the function of LAT and LAB in the regulation of development and activation of immune cells.
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Affiliation(s)
- Deirdre M Fuller
- Department of Immunology, Duke University Medical Center, Durham, NC 27710, USA
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32
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Pre-existing clusters of the adaptor Lat do not participate in early T cell signaling events. Nat Immunol 2011; 12:655-62. [PMID: 21642986 DOI: 10.1038/ni.2049] [Citation(s) in RCA: 246] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2011] [Accepted: 05/05/2011] [Indexed: 01/21/2023]
Abstract
Engaged T cell antigen receptors (TCRs) initiate signaling through the adaptor protein Lat. In quiescent T cells, Lat is segregated into clusters on the cell surface, which raises the question of how TCR triggering initiates signaling. Using super-resolution fluorescence microscopy, we found that pre-existing Lat domains were neither phosphorylated nor laterally transported to TCR activation sites, which suggested that these clusters do not participate in TCR signaling. Instead, TCR activation resulted in the recruitment and phosphorylation of Lat from subsynaptic vesicles. Studies of Lat mutants confirmed that recruitment preceded and was essential for phosphorylation and that both processes were independent of surface clustering of Lat. Our data suggest that TCR ligation preconditions the membrane for vesicle recruitment and bulk activation of the Lat signaling network.
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33
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Singh Y, Dyson J, Garden OA. Use of SNARF-1 to measure murine T cell proliferation in vitro and its application in a novel regulatory T cell suppression assay. Immunol Lett 2011; 140:21-9. [PMID: 21664378 DOI: 10.1016/j.imlet.2011.05.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2010] [Revised: 05/09/2011] [Accepted: 05/25/2011] [Indexed: 12/22/2022]
Abstract
The green fluorescent dye carboxyfluorescein diacetate succinimidyl ester (CFSE) has been used to track the proliferation of T cells in vitro. Such assays often incorporate more than one population of cells, but the paucity of alternative, spectrally distinct dyes suitable for measuring proliferation has hampered the simultaneous tracking of multiple cell populations; furthermore, CFSE is not compatible with green fluorescent protein (GFP), used to identify T cells in various transgenic mice. We have therefore validated the use of the far red dye seminaphthorhodafluor-1 (SNARF)-1 - originally developed to measure intracellular pH - to track murine T cell proliferation in vitro, demonstrating its ability to distinguish multiple cycles of proliferation over three days in a similar fashion to CFSE. The small changes in fluorescence emission attributed to intracellular alkalinisation of proliferating T cells have minimal impact on the ability of SNARF-1 to track cell division and this dye induces minimal cell death at the concentration used in this application. On the basis of these results, we have developed a novel in vitro murine T cell suppression assay, in which the proliferation of both conventional T cells (Tcons) stained with SNARF-1 and regulatory T cells (Tregs) stained with CFSE can be measured simultaneously. We have also demonstrated that SNARF-1 may be used to stain Tcons in assays of suppression involving 'designer' Tregs, generated by the transduction of CD4(+) T cells with constructs encoding the Foxp3(gfp) fusion protein.
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Affiliation(s)
- Yogesh Singh
- Regulatory T Cell Laboratory, Infection and Immunity Research Group, Department of Veterinary Clinical Sciences, The Royal Veterinary College, Camden Campus, Royal College Street, London, NW1 0TU, United Kingdom
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