151
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Treg Cell Differentiation: From Thymus to Peripheral Tissue. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2015; 136:175-205. [PMID: 26615097 DOI: 10.1016/bs.pmbts.2015.07.014] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Regulatory T cells (Tregs) are crucial mediators of self-tolerance in the periphery. They differentiate in the thymus, where interactions with thymus-resident antigen-presenting cells, an instructive cytokine milieu, and stimulation of the T cell receptor lead to the selection into the Treg lineage and the induction of Foxp3 gene expression. Once mature, Treg cells leave the thymus and migrate into either the secondary lymphoid tissues, e.g., lymph nodes and spleen, or peripheral nonlymphoid tissues. There is growing evidence that Treg cells go beyond the classical modulation of immune responses and also play important functional roles in nonlymphoid peripheral tissues. In this review, we summarize recent findings about the thymic Treg lineage differentiation as well as the further specialization of Treg cells in the secondary lymphoid and in the peripheral nonlymphoid organs.
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152
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T follicular regulatory cells in the regulation of B cell responses. Trends Immunol 2015; 36:410-8. [PMID: 26091728 DOI: 10.1016/j.it.2015.05.005] [Citation(s) in RCA: 214] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Revised: 05/12/2015] [Accepted: 05/13/2015] [Indexed: 12/13/2022]
Abstract
High affinity antibodies result from interactions between B cells and T follicular helper (Tfh) cells in germinal centers (GCs). Recent studies have identified an effector subset of T regulatory cells termed T follicular regulatory (Tfr) cells that specifically controls GC responses by suppressing Tfh and B cells. The discovery of Tfr cells has shed new light on pathways regulating humoral immunity that enable potent and specific responses to pathogens while restricting autoimmunity. Here, we review the current understanding of the cellular and molecular mechanisms underlying the differentiation and function of Tfr cells. In this context we discuss recent insights into the role of Tfh cells in disease, how this knowledge may be translated therapeutically, and important areas of further research.
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153
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Lu FT, Yang W, Wang YH, Ma HD, Tang W, Yang JB, Li L, Ansari AA, Lian ZX. Thymic B cells promote thymus-derived regulatory T cell development and proliferation. J Autoimmun 2015; 61:62-72. [PMID: 26071985 DOI: 10.1016/j.jaut.2015.05.008] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2015] [Revised: 05/19/2015] [Accepted: 05/21/2015] [Indexed: 01/10/2023]
Abstract
Thymic CD4(+) FoxP3(+) regulatory T (Treg) cells are critical for the development of immunological tolerance and immune homeostasis and requires contributions of both thymic dendritic and epithelial cells. Although B cells have been reported to be present within the thymus, there has not hitherto been a definition of their role in immune cell development and, in particular, whether or how they contribute to the Treg cellular thymic compartment. Herein, using both phenotypic and functional approaches, we demonstrate that thymic B cells contribute to the maintenance of thymic Treg cells and, using an in vitro culture system, demonstrate that thymic B cells contribute to the size of the thymic Treg compartment via cell-cell MHC II contact and the involvement of two independent co-stimulatory pathways that include interactions between the CD40/CD80/CD86 co-stimulatory molecules. Our data also suggest that thymic B cells promote the generation of thymic Treg cell precursors (pre-Treg cells), but not the conversion of FoxP3(+) Treg cells from pre-Treg cells. In addition, thymic B cells directly promote the proliferation of thymic Treg cells that is MHC II contact dependent with a minimal if any role for co-stimulatory molecules including CD40/CD80/CD86. Both pathways are independent of TGFβ. In conclusion, we rigorously define the critical role of thymic B cells in the development of thymic Treg cells from non-Treg to precursor stage and in the proliferation of mature thymic Treg cells.
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Affiliation(s)
- Fang-Ting Lu
- Liver Immunology Laboratory, Institute of Immunology and The CAS Key Laboratory of Innate Immunity and Chronic Disease, School of Life Sciences and Medical Center, University of Science and Technology of China, Hefei, Anhui 230027, China.
| | - Wei Yang
- Liver Immunology Laboratory, Institute of Immunology and The CAS Key Laboratory of Innate Immunity and Chronic Disease, School of Life Sciences and Medical Center, University of Science and Technology of China, Hefei, Anhui 230027, China.
| | - Yin-Hu Wang
- Liver Immunology Laboratory, Institute of Immunology and The CAS Key Laboratory of Innate Immunity and Chronic Disease, School of Life Sciences and Medical Center, University of Science and Technology of China, Hefei, Anhui 230027, China.
| | - Hong-Di Ma
- Liver Immunology Laboratory, Institute of Immunology and The CAS Key Laboratory of Innate Immunity and Chronic Disease, School of Life Sciences and Medical Center, University of Science and Technology of China, Hefei, Anhui 230027, China.
| | - Wei Tang
- Liver Immunology Laboratory, Institute of Immunology and The CAS Key Laboratory of Innate Immunity and Chronic Disease, School of Life Sciences and Medical Center, University of Science and Technology of China, Hefei, Anhui 230027, China.
| | - Jing-Bo Yang
- Liver Immunology Laboratory, Institute of Immunology and The CAS Key Laboratory of Innate Immunity and Chronic Disease, School of Life Sciences and Medical Center, University of Science and Technology of China, Hefei, Anhui 230027, China.
| | - Liang Li
- Liver Immunology Laboratory, Institute of Immunology and The CAS Key Laboratory of Innate Immunity and Chronic Disease, School of Life Sciences and Medical Center, University of Science and Technology of China, Hefei, Anhui 230027, China.
| | - Aftab A Ansari
- Department of Pathology, Emory University School of Medicine, Atlanta, GA 30322, USA.
| | - Zhe-Xiong Lian
- Liver Immunology Laboratory, Institute of Immunology and The CAS Key Laboratory of Innate Immunity and Chronic Disease, School of Life Sciences and Medical Center, University of Science and Technology of China, Hefei, Anhui 230027, China; Innovation Center for Cell Signaling Network, Hefei National Laboratory for Physical Sciences at Microscale, Hefei, Anhui 230026, China.
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154
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Liberal R, Grant CR, Longhi MS, Mieli-Vergani G, Vergani D. Regulatory T cells: Mechanisms of suppression and impairment in autoimmune liver disease. IUBMB Life 2015; 67:88-97. [PMID: 25850692 DOI: 10.1002/iub.1349] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Accepted: 11/11/2015] [Indexed: 12/24/2022]
Abstract
There are three classic liver diseases with probable autoimmune etiology: primary biliary cirrhosis, primary sclerosing cholangitis, and autoimmune hepatitis. The occurrence of these autoimmune conditions is determined by the breakdown of immune-regulatory mechanisms that in health are responsible for maintaining immunological tolerance against self-antigens. Among the multiple T cell subsets with suppressive function, the regulatory T cells (Tregs), defined by the expression of CD4, the IL-2 receptor α chain (CD25), and the transcription factor FOXP3, have emerged as having a central role in maintaining immune-tolerance to autoantigens. Tregs are equipped with an array of mechanisms of suppression, including the modulation of antigen presenting cell maturation and function, the killing of target cells, the disruption of metabolic pathways, and the production of anti-inflammatory cytokines. In all the three autoimmune liver diseases mentioned above, there is evidence pointing for either a reduced frequency and/or function of Tregs. Here, we review the definition, phenotypic characteristics, and mechanisms of suppression employed by Tregs and then we discuss the evidence available pointing to their impairment in patients with autoimmune liver disease.
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Affiliation(s)
- Rodrigo Liberal
- Institute of Liver Studies and Paediatric Liver, GI & Nutrition Centre, King's College London School of Medicine at King's College Hospital, London, UK
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155
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Franckaert D, Dooley J, Roos E, Floess S, Huehn J, Luche H, Fehling HJ, Liston A, Linterman MA, Schlenner SM. Promiscuous Foxp3-cre activity reveals a differential requirement for CD28 in Foxp3⁺ and Foxp3⁻ T cells. Immunol Cell Biol 2015; 93:417-23. [PMID: 25533288 PMCID: PMC4407013 DOI: 10.1038/icb.2014.108] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Revised: 11/03/2014] [Accepted: 11/13/2014] [Indexed: 01/07/2023]
Abstract
Costimulatory signals by CD28 are critical for thymic regulatory T-cell (Treg) development. To determine the functional relevance of CD28 for peripheral Treg post thymic selection, we crossed the widely used Forkhead box protein 3 (Foxp3)-CreYFP mice to mice bearing a conditional Cd28 allele. Treg-specific CD28 deficiency provoked a severe autoimmune syndrome as a result of a strong disadvantage in competitive fitness and proliferation of CD28-deficient Tregs. By contrast, Treg survival and lineage integrity were not affected by the lack of CD28. This data demonstrate that, even after the initial induction requirement, Treg maintain a higher dependency on CD28 signalling than conventional T cells for homeostasis. In addition, we found the Foxp3-CreYFP allele to be a hypomorph, with reduced Foxp3 protein levels. Furthermore, we report here the stochastic activity of the Foxp3-CreYFP allele in non-Tregs, sufficient to recombine some conditional alleles (including Cd28) but not others (including R26-RFP). This hypomorphism and 'leaky' expression of the Foxp3-CreYFP allele should be considered when analysing the conditionally mutated Treg.
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Affiliation(s)
- Dean Franckaert
- Autoimmune Genetics Laboratory, VIB, Leuven, Belgium
- Department of Microbiology and Immunology, University of Leuven, Leuven, Belgium
| | - James Dooley
- Autoimmune Genetics Laboratory, VIB, Leuven, Belgium
- Department of Microbiology and Immunology, University of Leuven, Leuven, Belgium
| | - Evelyne Roos
- Autoimmune Genetics Laboratory, VIB, Leuven, Belgium
- Department of Microbiology and Immunology, University of Leuven, Leuven, Belgium
| | - Stefan Floess
- Department of Experimental Immunology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Jochen Huehn
- Department of Experimental Immunology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Herve Luche
- Centre d'Immunologie de Marseille-Luminy (CIML), UM2 Aix-Marseille Université, Marseille Cedex 9, France
- INSERM U1104, Marseille Cedex 9, France
- CNRS UMR7280, Marseille Cedex 9, France
| | | | - Adrian Liston
- Autoimmune Genetics Laboratory, VIB, Leuven, Belgium
- Department of Microbiology and Immunology, University of Leuven, Leuven, Belgium
| | - Michelle A Linterman
- Lymphocyte Signalling and Development, Babraham Institute, Babraham Research Campus, Cambridge, UK
| | - Susan M Schlenner
- Autoimmune Genetics Laboratory, VIB, Leuven, Belgium
- Department of Microbiology and Immunology, University of Leuven, Leuven, Belgium
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156
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Akieda Y, Wakamatsu E, Nakamura T, Ishida Y, Ogawa S, Abe R. Defects in Regulatory T Cells Due to CD28 Deficiency Induce a Qualitative Change of Allogeneic Immune Response in Chronic Graft-versus-Host Disease. THE JOURNAL OF IMMUNOLOGY 2015; 194:4162-74. [DOI: 10.4049/jimmunol.1402591] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Accepted: 02/25/2015] [Indexed: 01/03/2023]
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157
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Chen W, Konkel JE. Development of thymic Foxp3(+) regulatory T cells: TGF-β matters. Eur J Immunol 2015; 45:958-65. [PMID: 25684698 DOI: 10.1002/eji.201444999] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2014] [Revised: 02/07/2015] [Accepted: 02/09/2015] [Indexed: 01/22/2023]
Abstract
CD4(+) regulatory T cells expressing the transcription factor Foxp3 can be generated in the thymus (tTreg cells), but the cellular and molecular pathways driving their development remain incompletely understood. TGF-β is essential for the generation of Foxp3(+) Treg cells converted from peripheral naïve CD4(+) T cells (pTreg cells), yet a role for TGF-β in tTreg-cell development was initially refuted. Nevertheless, recent studies have unmasked a requirement for TGF-β in the generation of tTreg cells. Experimental evidence reveals that TGF-β in the context of TCR stimulation induces Foxp3 gene transcription in thymic Treg precursors, CD4(+) CD8(-) CD25(-) semimature and mature single-positive thymocytes. Intriguingly, thymic apoptosis was found to be intrinsically linked to the generation of tTreg cells, as apoptosis induced expression of TGF-β intrathymically. In this short review, we will highlight key data, discuss the experimental evidence and propose a modified model of tTreg-cell development involving TGF-β. We will also outline the remaining unresolved questions concerning generation of thymic Foxp3(+) Treg cells and provide our personal perspectives on the mechanisms controlling tTreg-cell development.
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Affiliation(s)
- WanJun Chen
- Mucosal Immunology Section, OPCB, NIDCR, 30 Convent Dr., Bethesda, MD, USA
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158
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Poggi M, Morin SO, Bastelica D, Govers R, Canault M, Bernot D, Georgelin O, Verdier M, Burcelin R, Olive D, Alessi MC, Peiretti F, Nunès JA. CD28 deletion improves obesity-induced liver steatosis but increases adiposity in mice. Int J Obes (Lond) 2015; 39:977-85. [PMID: 25771927 DOI: 10.1038/ijo.2015.26] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2014] [Revised: 12/22/2014] [Accepted: 02/08/2015] [Indexed: 01/31/2023]
Abstract
BACKGROUND/OBJECTIVES Lymphocytes have a critical role in visceral adipose tissue (AT) inflammation. The CD28 costimulatory molecule is required for lymphocyte activation and for the development of a functional regulatory T cells (Tregs) compartment; however, its role during obesity is unknown. METHODS During diet-induced obesity, we investigated the effects of selective interference with CD28 signaling using knockout mice (Cd28KO) and a CTLA4-Ig fusion protein inhibiting CD28-B7 interactions. RESULTS Cd28 deficiency decreased pathogenic T cells and Treg content within AT without changing the macrophages number. Cd28KO epididymal but not subcutaneous fat was characterized by enlarged adipocytes, reduced levels of inflammatory cytokines and increased Glut4, adiponectin and lipogenic enzyme mRNA levels. This was associated with reduced inflammation, fat accumulation and enhanced glucose metabolism in liver. Weight gain and fasting glucose tolerance were not affected. CTLA4-Ig injections reduced the number of T cells in epididymal AT (epiAT) but not the inflammatory cytokines levels and failed to improve liver fat accumulation. CONCLUSIONS Deletion of CD28 creates a new pro/anti-inflammatory balance in epiAT and liver and exerts a protective effect against hepatic steatosis.
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Affiliation(s)
- M Poggi
- 1] Inserm, U1062, Marseilles, France [2] Inra, UMR1260, Marseilles, France [3] Aix-Marseille Université, NORT, Marseilles, France
| | - S O Morin
- 1] Inserm, U1068, CRCM, Marseilles, France [2] Institut Paoli-Calmettes, Marseilles, France [3] Aix-Marseille Université, UM 105, Marseilles, France [4] CNRS, UMR7258, CRCM, Marseilles, France
| | - D Bastelica
- 1] Inserm, U1062, Marseilles, France [2] Inra, UMR1260, Marseilles, France [3] Aix-Marseille Université, NORT, Marseilles, France
| | - R Govers
- 1] Inserm, U1062, Marseilles, France [2] Inra, UMR1260, Marseilles, France [3] Aix-Marseille Université, NORT, Marseilles, France
| | - M Canault
- 1] Inserm, U1062, Marseilles, France [2] Inra, UMR1260, Marseilles, France [3] Aix-Marseille Université, NORT, Marseilles, France
| | - D Bernot
- 1] Inserm, U1062, Marseilles, France [2] Inra, UMR1260, Marseilles, France [3] Aix-Marseille Université, NORT, Marseilles, France
| | - O Georgelin
- 1] Inserm, U1062, Marseilles, France [2] Inra, UMR1260, Marseilles, France [3] Aix-Marseille Université, NORT, Marseilles, France
| | - M Verdier
- 1] Inserm, U1062, Marseilles, France [2] Inra, UMR1260, Marseilles, France [3] Aix-Marseille Université, NORT, Marseilles, France
| | - R Burcelin
- 1] Inserm, U1048, Toulouse, France [2] Université Paul Sabatier, IMC, Toulouse Cedex 4, France
| | - D Olive
- 1] Inserm, U1068, CRCM, Marseilles, France [2] Institut Paoli-Calmettes, Marseilles, France [3] Aix-Marseille Université, UM 105, Marseilles, France [4] CNRS, UMR7258, CRCM, Marseilles, France
| | - M-C Alessi
- 1] Inserm, U1062, Marseilles, France [2] Inra, UMR1260, Marseilles, France [3] Aix-Marseille Université, NORT, Marseilles, France
| | - F Peiretti
- 1] Inserm, U1062, Marseilles, France [2] Inra, UMR1260, Marseilles, France [3] Aix-Marseille Université, NORT, Marseilles, France
| | - J A Nunès
- 1] Inserm, U1068, CRCM, Marseilles, France [2] Institut Paoli-Calmettes, Marseilles, France [3] Aix-Marseille Université, UM 105, Marseilles, France [4] CNRS, UMR7258, CRCM, Marseilles, France
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159
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Williams JA, Tai X, Hodes RJ. CD28-CD80/86 and CD40-CD40L Interactions Promote Thymic Tolerance by Regulating Medullary Epithelial Cell and Thymocyte Development. Crit Rev Immunol 2015; 35:59-76. [PMID: 25746048 DOI: 10.1615/critrevimmunol.2015012501] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Development and central tolerance of T lymphocytes in the thymus requires both TCR signals and collaboration with signals generated through costimulatory molecule interactions. In this review, we discuss the importance of CD28-CD80/86 and CD40-CD40L costimulatory interactions in promoting normal thymic development. This discussion includes roles in the generation of a normal thymic medulla, in the development of specific T-cells subsets, including iNKT and T regulatory cells, and in the generation of a tolerant mature T-cell repertoire. We discuss recent contributions to the understanding of CD28-CD80/86 and CD40-CD40L costimulatory interactions in thymic development, and we highlight the ways in which the many important roles mediated by these interactions collaborate to promote normal thymic development.
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Affiliation(s)
- Joy A Williams
- Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892
| | - Xuguang Tai
- Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892
| | - Richard J Hodes
- Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892
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160
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Yang ZZ, Liang AB, Ansell SM. T-cell-mediated antitumor immunity in B-cell non-Hodgkin lymphoma: activation, suppression and exhaustion. Leuk Lymphoma 2015; 56:2498-504. [PMID: 25651421 DOI: 10.3109/10428194.2015.1011640] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The tumor microenvironment in B-cell non-Hodgkin lymphoma (NHL) comprises not only malignant cells but also significant numbers of normal immune cells. The intratumoral immune infiltrate includes T-lymphocytes that appear to target the malignant clone. Despite immunologically recognizing the lymphoma cells, the intratumoral T-cells are unable to eradicate the malignant cells and the lymphoma commonly progresses. Recent data has identified mechanisms whereby activated intratumoral T-cells are suppressed or become exhausted due to chronic antigen stimulation. A clearer understanding of these mechanisms will allow for strategies to overcome them and improve the outcome of patients with lymphoma.
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Affiliation(s)
- Zhi-Zhang Yang
- a Division of Hematology and Internal Medicine, Mayo Clinic , Rochester , MN , USA
| | - Ai-Bin Liang
- b Department of Hematology , Tongji Hospital, Tongji University , Shanghai , China
| | - Stephen M Ansell
- a Division of Hematology and Internal Medicine, Mayo Clinic , Rochester , MN , USA
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161
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Conserved and divergent aspects of human T-cell development and migration in humanized mice. Immunol Cell Biol 2015; 93:716-26. [PMID: 25744551 PMCID: PMC4575952 DOI: 10.1038/icb.2015.38] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Revised: 02/09/2015] [Accepted: 02/09/2015] [Indexed: 02/07/2023]
Abstract
Humanized mice represent an important model to study the development and function of the human immune system. While it is known that mouse thymic stromal cells can support human T-cell development, the extent of interspecies cross-talk and the degree to which these systems recapitulate normal human T-cell development remain unclear. To address these questions, we compared conventional and non-conventional T-cell development in a neonatal chimera humanized mouse model with that seen in human fetal and neonatal thymus samples, and also examined the impact of a human HLA-A2 transgene expressed by the mouse stroma. Given that dynamic migration and cell–cell interactions are essential for T-cell differentiation, we also studied the intrathymic migration pattern of human thymocytes developing in a murine thymic environment. We found that both conventional T-cell development and intra-thymic migration patterns in humanized mice closely resemble human thymopoiesis. Additionally, we show that developing human thymocytes engage in short, serial interactions with other human hematopoietic-derived cells. However, non-conventional T-cell differentiation in humanized mice differed from both fetal and neonatal human thymopoiesis, including a marked deficiency of Foxp3+ T-cell development. These data suggest that although the murine thymic microenvironment can support a number of aspects of human T-cell development, important differences remain, and additional human-specific factors may be required.
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162
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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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163
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Zhao Y, Guo H, Qiao G, Zucker M, Langdon WY, Zhang J. E3 Ubiquitin Ligase Cbl-b Regulates Thymic-Derived CD4+CD25+ Regulatory T Cell Development by Targeting Foxp3 for Ubiquitination. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2015; 194:1639-45. [PMID: 25560411 PMCID: PMC4324371 DOI: 10.4049/jimmunol.1402434] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
CD28 costimulation is essential for the development of thymic-derived CD4(+)CD25(+)Foxp3(+) regulatory T cells ("tTregs"). E3 ubiquitin ligase Cbl-b has been shown to regulate CD28 dependence of T cell activation. In this paper, we report that the loss of Cbl-b partially but significantly rescues the defective development of tTregs in Cd28(-/-) mice. This partial rescue is independent of IL-2. Mechanistically, Cbl-b binds to Foxp3 upon TCR stimulation and, together with Stub1, targets Foxp3 for ubiquitination and subsequently degradation in the proteasome. As Cbl-b self-ubiquitination and proteasomal degradation is impaired in Cd28(-/-) T cells, the defective development of tTregs in Cd28(-/-) mice may in part be due to increased Foxp3 ubiquitination and degradation targeted by Stub1 and Cbl-b. Treating Cd28(-/-) mice with a proteasome inhibitor completely rescues defective tTreg development in these mice. Therefore, Cbl-b, together with Stub1, ubiquitinate Foxp3, and regulate tTreg development.
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Affiliation(s)
- Yixia Zhao
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH 43210
| | - Hui Guo
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH 43210
| | - Guilin Qiao
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH 43210; Section of Nephrology, Department of Medicine, University of Chicago, Chicago, IL 60637; and
| | - Mark Zucker
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH 43210
| | - Wallace Y Langdon
- School of Pathology and Laboratory Medicine, University of Western Australia, Crawley, Western Australia 6009, Australia
| | - Jian Zhang
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH 43210; Section of Nephrology, Department of Medicine, University of Chicago, Chicago, IL 60637; and
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164
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The chromatin-modifying enzyme Ezh2 is critical for the maintenance of regulatory T cell identity after activation. Immunity 2015; 42:227-238. [PMID: 25680271 DOI: 10.1016/j.immuni.2015.01.007] [Citation(s) in RCA: 221] [Impact Index Per Article: 24.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Revised: 12/05/2014] [Accepted: 01/22/2015] [Indexed: 01/04/2023]
Abstract
Regulatory T cells (Treg cells) are required for immune homeostasis. Chromatin remodeling is essential for establishing diverse cellular identities, but how the epigenetic program in Treg cells is maintained throughout the dynamic activation process remains unclear. Here we have shown that CD28 co-stimulation, an extracellular cue intrinsically required for Treg cell maintenance, induced the chromatin-modifying enzyme, Ezh2. Treg-specific ablation of Ezh2 resulted in spontaneous autoimmunity with reduced Foxp3(+) cells in non-lymphoid tissues and impaired resolution of experimental autoimmune encephalomyelitis. Utilizing a model designed to selectively deplete wild-type Treg cells in adult mice co-populated with Ezh2-deficient Treg cells, Ezh2-deficient cells were destabilized and failed to prevent autoimmunity. After activation, the transcriptome of Ezh2-deficient Treg cells was disrupted, with altered expression of Treg cell lineage genes in a pattern similar to Foxp3-deficient Treg cells. These studies reveal a critical role for Ezh2 in the maintenance of Treg cell identity during cellular activation.
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165
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Chen X, Willette-Brown J, Wu X, Hu Y, Howard OMZ, Hu Y, Oppenheim JJ. IKKα is required for the homeostasis of regulatory T cells and for the expansion of both regulatory and effector CD4 T cells. FASEB J 2015; 29:443-54. [PMID: 25376833 PMCID: PMC4314223 DOI: 10.1096/fj.14-259564] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 09/18/2014] [Indexed: 12/18/2022]
Abstract
It was reported that TNF receptor type II signaling, which has the capacity to stimulate CD4+ forkhead box P3+ (Foxp3+) regulatory T cells (Tregs), activated the noncanonical NF-κB pathway in an IKKα-dependent manner. Therefore, we studied the role of IKKα in the homeostasis of Treg population. To this end, we generated a mouse strain with conditional knockout of IKKα in CD4 cells (Ikkα(f/f):CD4.Cre) that showed a >60% reduction in the number of Tregs in the thymus and peripheral lymphoid tissues, whereas the number of Foxp3- effector T cells (Teffs) remained at a normal level. The function of Tregs deficient in IKKα was examined using Rag1(-/-) mice cotransferred with naive CD4 cells (nCD4s). Although wild-type (WT) Tregs inhibited colitis induced by transfer of WT nCD4s, IKKα-deficient Tregs failed to do so, which was associated with their inability to reconstitute Rag1(-/-) mice. Furthermore, nCD4s deficient in IKKα also failed to reconstitute Rag1(-/-) mice and were defective in proliferative responses in vitro and in vivo. Thus, our study reveals a novel role of IKKα in the maintenance of a normal Treg population and in the control of expansion of CD4 T cells. These properties of IKKα may be exploited as therapeutic strategies in the treatment of major human diseases.
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Affiliation(s)
- Xin Chen
- Basic Science Program, Leidos Biomedical Research, Incorporated, Laboratory of Molecular Immunoregulation, and State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao SAR, China
| | - Jami Willette-Brown
- Laboratory of Experimental Immunology, Cancer Inflammation Program, Center for Cancer Research, National Cancer Institute, Frederick, Maryland, USA
| | - Xueqiang Wu
- Laboratory of Molecular Immunoregulation, and
| | - Ya Hu
- Laboratory of Molecular Immunoregulation, and
| | | | - Yinling Hu
- Laboratory of Experimental Immunology, Cancer Inflammation Program, Center for Cancer Research, National Cancer Institute, Frederick, Maryland, USA
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166
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Homeostatic control of memory cell progenitors in the natural killer cell lineage. Cell Rep 2015; 10:280-91. [PMID: 25578733 DOI: 10.1016/j.celrep.2014.12.025] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Revised: 11/03/2014] [Accepted: 12/11/2014] [Indexed: 01/07/2023] Open
Abstract
Recent studies have demonstrated that natural killer (NK) cells are able to undergo clonal expansion and contraction and to generate self-renewing memory cells after infection with mouse cytomegalovirus (MCMV). It is unclear whether all or only certain subsets preferentially contribute to the generation of memory NK cells. Here, we show that memory NK cells predominantly arise from killer cell lectin-like receptor G1 (KLRG1)-negative NK cell progenitors, whereas KLRG1-positive NK cells have limited capacity for expansion during infection with MCMV. Unexpectedly, the frequency of KLRG1-positive NK cells is significantly affected by the presence of T cells in the host and potentially by the host microbiota. Our findings demonstrate that excessive availability of interleukin (IL)-15 may erode the pool of memory progenitors, resulting in the decreased efficiency of memory generation in the NK cell lineage.
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167
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Understanding the Roles of the NF-κB Pathway in Regulatory T Cell Development, Differentiation and Function. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2015; 136:57-67. [DOI: 10.1016/bs.pmbts.2015.08.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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168
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Transcriptional and Epigenetic Control of Regulatory T Cell Development. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2015; 136:1-33. [DOI: 10.1016/bs.pmbts.2015.07.011] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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169
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Thauland TJ, Koguchi Y, Dustin ML, Parker DC. CD28-CD80 interactions control regulatory T cell motility and immunological synapse formation. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2014; 193:5894-903. [PMID: 25355918 PMCID: PMC4258405 DOI: 10.4049/jimmunol.1401752] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Regulatory T cells (Tregs) are essential for tolerance to self and environmental Ags, acting in part by downmodulating costimulatory molecules on the surface of dendritic cells (DCs) and altering naive CD4 T cell-DC interactions. In this study, we show that Tregs form stable conjugates with DCs before, but not after, they decrease surface expression of the costimulatory molecule CD80 on the DCs. We use supported planar bilayers to show that Tregs dramatically slow down but maintain a highly polarized and motile phenotype after recognizing Ag in the absence of costimulation. These motile cells are characterized by distinct accumulations of LFA-1-ICAM-1 in the lamella and TCR-MHC in the uropod, consistent with a motile immunological synapse or "kinapse." However, in the presence of high, but not low, concentrations of CD80, Tregs form stationary, symmetrical synapses. Using blocking Abs, we show that, whereas CTLA-4 is required for CD80 downmodulation, CD28-CD80 interactions are critical for modulating Treg motility in the presence of Ag. Taken together, these results support the hypothesis that Tregs are tuned to alter their motility depending on costimulatory signals.
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Affiliation(s)
- Timothy J Thauland
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, OR 97239;
| | - Yoshinobu Koguchi
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, OR 97239
| | - Michael L Dustin
- Department of Pathology, New York University School of Medicine, New York, NY 10016; and Kennedy Institute of Rheumatology, Nuffield Department of Orthopaedics, Rheumatology, and Musculoskeletal Sciences, University of Oxford, Oxford OX3 7FY, United Kingdom
| | - David C Parker
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, OR 97239;
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170
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Barbi J, Pardoll D, Pan F. Treg functional stability and its responsiveness to the microenvironment. Immunol Rev 2014; 259:115-39. [PMID: 24712463 DOI: 10.1111/imr.12172] [Citation(s) in RCA: 171] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Regulatory T cells (Tregs) prevent autoimmunity and tissue damage resulting from excessive or unnecessary immune activation through their suppressive function. While their importance for proper immune control is undeniable, the stability of the Treg lineage has recently become a controversial topic. Many reports have shown dramatic loss of the signature Treg transcription factor Forkhead box protein 3 (Foxp3) and Treg function under various inflammatory conditions. Other recent studies demonstrate that most Tregs are extremely resilient in their expression of Foxp3 and the retention of suppressive function. While this debate is unlikely to be settled in the immediate future, improved understanding of the considerable heterogeneity within the Foxp3(+) Treg population and how Treg subsets respond to ranging environmental cues may be keys to reconciliation. In this review, we discuss the diverse mechanisms responsible for the observed stability or instability of Foxp3(+) Treg identity and function. These include transcriptional and epigenetic programs, transcript targeting, and posttranslational modifications that appear responsive to numerous elements of the microenvironment. These mechanisms for Treg functional modulation add to the discussion of Treg stability.
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Affiliation(s)
- Joseph Barbi
- Department of Oncology, Immunology and Hematopoiesis Division, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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171
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Thymus-deriving natural regulatory T cell generation in vitro: role of the source of activation signals. Immunol Lett 2014; 162:199-209. [PMID: 25445615 DOI: 10.1016/j.imlet.2014.10.024] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Revised: 10/09/2014] [Accepted: 10/21/2014] [Indexed: 12/20/2022]
Abstract
In this research we have examined different sources of activation signals in order to optimize culture conditions for in vitro generation of thymus-deriving natural regulatory T cells (nTregs). We have established a novel model using JAWS II dendritic cell line of immature phenotype and compared it to commonly used methods for the generation of Tregs from peripheral lymphoid organs or blood T cells. In our model the first activation signal is provided by anti-CD3 monoclonal antibodies while the second is delivered by costimulatory molecules expressed on JAWS II cells. The presence of JAWS II cells co-cultured in vitro with unsorted thymocytes directly isolated from the thymus gland creates environment favoring SP CD4+ differentiation, provides the apoptotic cells clearance, maintains the survival of thymocytes and facilitate nTreg generation. Moreover the usage of immature dendritic cells stimuli enables to conduct research on agents affecting nTreg survival, proliferation and development in conditions of cell-to-cell contact of undifferentiated thymocytes with dendritic cells.
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172
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Marshall D, Sinclair C, Tung S, Seddon B. Differential requirement for IL-2 and IL-15 during bifurcated development of thymic regulatory T cells. THE JOURNAL OF IMMUNOLOGY 2014; 193:5525-33. [PMID: 25348623 DOI: 10.4049/jimmunol.1402144] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The developmental pathways of regulatory T cells (T(reg)) generation in the thymus are not fully understood. In this study, we reconstituted thymic development of Zap70-deficient thymocytes with a tetracycline-inducible Zap70 transgene to allow temporal dissection of T(reg) development. We find that T(reg) develop with distinctive kinetics, first appearing by day 4 among CD4 single-positive (SP) thymocytes. Accepted models of CD25(+)Foxp3(+) T(reg) selection suggest development via CD25(+)Foxp3(-) CD4 SP precursors. In contrast, our kinetic analysis revealed the presence of abundant CD25(-)Foxp3(+) cells that are highly efficient at maturing to CD25(+)Foxp3(+) cells in response to IL-2. CD25(-)Foxp3(+) cells more closely resembled mature T(reg) both with respect to kinetics of development and avidity for self-peptide MHC. These population also exhibited distinct requirements for cytokines during their development. CD25(-)Foxp3(+) cells were IL-15 dependent, whereas generation of CD25(+)Foxp3(+) specifically required IL-2. Finally, we found that IL-2 and IL-15 arose from distinct sources in vivo. IL-15 was of stromal origin, whereas IL-2 was of exclusively from hemopoetic cells that depended on intact CD4 lineage development but not either Ag-experienced or NKT cells.
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Affiliation(s)
- Daniel Marshall
- Division of Immune Cell Biology, Medical Research Council National Institute for Medical Research, London, NW7 1AA, United Kingdom
| | - Charles Sinclair
- Division of Immune Cell Biology, Medical Research Council National Institute for Medical Research, London, NW7 1AA, United Kingdom
| | - Sim Tung
- Division of Immune Cell Biology, Medical Research Council National Institute for Medical Research, London, NW7 1AA, United Kingdom
| | - Benedict Seddon
- Division of Immune Cell Biology, Medical Research Council National Institute for Medical Research, London, NW7 1AA, United Kingdom
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173
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Chevalier N, Thorburn AN, Macia L, Tan J, Juglair L, Yagita H, Yu D, Hansbro PM, Mackay CR. Inflammation and lymphopenia trigger autoimmunity by suppression of IL-2-controlled regulatory T cell and increase of IL-21-mediated effector T cell expansion. THE JOURNAL OF IMMUNOLOGY 2014; 193:4845-58. [PMID: 25339665 DOI: 10.4049/jimmunol.1302966] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The dynamic interplay between regulatory T cells (T(regs)) and effector T cells (T(effs)) governs the balance between tolerance and effector immune responses. Perturbations of T(reg) frequency and function or imbalances in T(reg)/T(eff) levels are associated with the development of autoimmunity. The factors that mediate these changes remain poorly understood and were investigated in this study in murine autoimmune arthritis. T(regs) displayed a stable phenotype in arthritic mice and were fully functional in in vitro suppression assays. However, their expansion was delayed relative to T(effs) (T follicular helper cells and Th17 cells) during the early stages of autoimmune reactivity. This imbalance is likely to have led to insufficient T(reg) control of T(effs) and induced autoimmunity. Moreover, a counterregulatory and probably IL-7-driven increase in thymic T(reg) production and recruitment to inflamed tissues was too slow for disease prevention. Increased T(eff) over T(reg) expansion was further aggravated by inflammation and lymphopenia. Both these conditions contribute to autoimmune pathogenesis and were accompanied by decreases in the availability of IL-2 and increases in levels of IL-21. IL-2 neutralization or supplementation was used to show that T(reg) expansion mainly depended on this cytokine. IL-21R(-/-) cells were used to demonstrate that IL-21 promoted the maintenance of T(effs). Thus, at inflammatory sites in experimental arthritis, a deficit in IL-2 hampers T(reg) proliferation, whereas exaggerated IL-21 levels overwhelm T(reg) control by supporting T(eff) expansion. This identifies IL-2 and IL-21 as targets for manipulation in therapies for autoimmunity.
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Affiliation(s)
- Nina Chevalier
- Department of Rheumatology and Clinical Immunology, University Medical Centre Freiburg, 79106 Freiburg, Germany; Center for Immunology and Inflammation, Monash University Clayton, Melbourne, Victoria 3088, Australia; Immunology Department, Garvan Institute of Medical Research, Sydney, New South Wales 2010, Australia;
| | - Alison N Thorburn
- Center for Immunology and Inflammation, Monash University Clayton, Melbourne, Victoria 3088, Australia
| | - Laurence Macia
- Center for Immunology and Inflammation, Monash University Clayton, Melbourne, Victoria 3088, Australia
| | - Jian Tan
- Center for Immunology and Inflammation, Monash University Clayton, Melbourne, Victoria 3088, Australia
| | - Laurent Juglair
- Center for Immunology and Inflammation, Monash University Clayton, Melbourne, Victoria 3088, Australia
| | - Hideo Yagita
- Department of Immunology, Juntendo University School of Medicine, 113-8421 Tokyo, Japan; and
| | - Di Yu
- Center for Immunology and Inflammation, Monash University Clayton, Melbourne, Victoria 3088, Australia
| | - Philip M Hansbro
- Centre for Asthma and Respiratory Diseases, Hunter Medical Research Institute, University of Newcastle, Newcastle, New South Wales 2300, Australia
| | - Charles R Mackay
- Center for Immunology and Inflammation, Monash University Clayton, Melbourne, Victoria 3088, Australia
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174
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Shibuya K, Nakano N. Interleukin-2 drives immature double negative thymocytes into γδ T cells expressing Foxp3 on a stromal cell line in vitro. Biochem Biophys Res Commun 2014; 452:912-9. [PMID: 25218473 DOI: 10.1016/j.bbrc.2014.08.155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Accepted: 08/29/2014] [Indexed: 11/28/2022]
Abstract
γδ T cells are exported from the thymus as innate-like lymphocytes that can immediately respond to antigens. In the thymus, γδ T cells diverge into functionally distinct lineages. It is not known whether γδ T cells differentiate into regulatory cells that express Foxp3, which is an essential transcription factor for CD4(+) regulatory T cells. In this study, we analyzed CD25(+) immature thymocytes that give rise to both αβ and γδ thymocytes. These precursor cells have the potential to differentiate into Foxp3(+) γδ T cells on a stromal cell line, TSt4-Dll1. Development of Foxp3(+) γδ thymocytes in this culture was dependent on IL-2. IL-2 stimulation induced Id3, Egr1, and Egr3 expression in CD25(+) immature thymocytes, suggesting that it could activate signaling molecules that are downstream of TCR signaling. The induction of Foxp3 in precursor γδ T cells suggested that IL-2 could activate the Foxp3 gene early in thymocyte development.
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Affiliation(s)
- Keita Shibuya
- Research Institute for Biomedical Sciences, Tokyo University of Science, 2669 Yamazaki, Noda, Chiba 278-0022, Japan
| | - Naoko Nakano
- Research Institute for Biomedical Sciences, Tokyo University of Science, 2669 Yamazaki, Noda, Chiba 278-0022, Japan.
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175
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Gardner D, Jeffery LE, Sansom DM. Understanding the CD28/CTLA-4 (CD152) pathway and its implications for costimulatory blockade. Am J Transplant 2014; 14:1985-91. [PMID: 25098238 DOI: 10.1111/ajt.12834] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Revised: 05/19/2014] [Accepted: 05/20/2014] [Indexed: 01/25/2023]
Abstract
T cell activation is a key event in the adaptive immune system and vital in the generation of protective cellular and humoral immunity. Activation is required to generate CD4 effector T cell responses and provide help for B cell and cytotoxic T cell responses. While defective T responses to foreign antigen result in infectious pathology, over-reactive T cell responses against self-antigens result in autoimmunity and, in a transplantation setting, tissue rejection. Understanding how T cell activation is normally regulated is critical to therapeutic intervention and the CD28/CTLA-4 (CD152) pathway represents the initial activation checkpoint in molecular terms. In particular, while the CTLA-4 pathway is well established as an essential regulator of self-reactivity, its mechanism of action is still uncertain. Such mechanistic issues are important given its central position in T cell activation and the increasing number of therapeutic modalities aimed at manipulating the CD28/CTLA-4 pathway. Here, we provide an updated view of CTLA-4 biology, reviewing the established features of the system and highlighting its interplay with CD28. We then discuss how recent progress in our understanding of this pathway affects our interpretations following intervention.
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Affiliation(s)
- D Gardner
- University of Birmingham, MRC Centre for Immune Regulation, Birmingham, UK
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176
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SOCS1 and regulation of regulatory T cells plasticity. J Immunol Res 2014; 2014:943149. [PMID: 25133199 PMCID: PMC4123481 DOI: 10.1155/2014/943149] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Revised: 06/10/2014] [Accepted: 06/30/2014] [Indexed: 01/07/2023] Open
Abstract
Several reports have suggested that natural regulatory T cells (Tregs) lose Forkhead box P3 (Foxp3) expression and suppression activity under certain inflammatory conditions. Treg plasticity has been studied because it may be associated with the pathogenesis of autoimmunity. Some studies showed that a minor uncommitted Foxp3+ T cell population, which lacks hypomethylation at Treg-specific demethylation regions (TSDRs), may convert to effector/helper T cells. Suppressor of cytokine signaling 1 (SOCS1), a negative regulator of cytokine signaling, has been reported to play an important role in Treg cell integrity and function by protecting the cells from excessive inflammatory cytokines. In this review, we discuss Treg plasticity and maintenance of suppression functions in both physiological and pathological settings. In addition, we discuss molecular mechanisms of maintaining Treg plasticity by SOCS1 and other molecules. Such information will be useful for therapy of autoimmune diseases and reinforcement of antitumor immunity.
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177
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Mahmud SA, Manlove LS, Farrar MA. Interleukin-2 and STAT5 in regulatory T cell development and function. JAKSTAT 2014; 2:e23154. [PMID: 24058794 PMCID: PMC3670270 DOI: 10.4161/jkst.23154] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Revised: 12/05/2012] [Accepted: 12/06/2012] [Indexed: 01/07/2023] Open
Abstract
Interleukin-2 and its downstream target STAT5 have effects on many aspects of immune function. This has been perhaps best documented in regulatory T cells. In this review we summarize the initial findings supporting a role for IL2 and STAT5 in regulatory T cell development and outline more recent studies describing how this critical signaling pathway entrains regulatory T cell differentiation and affects regulatory T cell function.
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Affiliation(s)
- Shawn A Mahmud
- Center for Immunology; Masonic Cancer Center; and Department of Laboratory Medicine and Pathology; University of Minnesota; Minneapolis, MN USA
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178
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Liu C, Wang HC, Yu S, Jin R, Tang H, Liu YF, Ge Q, Sun XH, Zhang Y. Id1 expression promotes T regulatory cell differentiation by facilitating TCR costimulation. THE JOURNAL OF IMMUNOLOGY 2014; 193:663-672. [PMID: 24920844 DOI: 10.4049/jimmunol.1302554] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
T regulatory (Treg) cells play crucial roles in the regulation of cellular immunity. The development of Treg cells depends on signals from TCRs and IL-2Rs and is influenced by a variety of transcription factors. The basic helix-loop-helix proteins are known to influence TCR signaling thresholds. Whether this property impacts Treg differentiation is not understood. In this study, we interrogated the role of basic helix-loop-helix proteins in the production of Treg cells using the CD4 promoter-driven Id1 transgene. We found that Treg cells continued to accumulate as Id1 transgenic mice aged, resulting in a significant increase in Treg cell counts in the thymus as well as in the periphery compared with wild-type controls. Data from mixed bone marrow assays suggest that Id1 acts intrinsically on developing Treg cells. We made a connection between Id1 expression and CD28 costimulatory signaling because Id1 transgene expression facilitated the formation of Treg precursors in CD28(-/-) mice and the in vitro differentiation of Treg cells on thymic dendritic cells despite the blockade of costimulation by anti-CD80/CD86. Id1 expression also allowed in vitro Treg differentiation without anti-CD28 costimulation, which was at least in part due to enhanced production of IL-2. Notably, with full strength of costimulatory signals, however, Id1 expression caused modest but significant suppression of Treg induction. Finally, we demonstrate that Id1 transgenic mice were less susceptible to the induction of experimental autoimmune encephalomyelitis, thus illustrating the impact of Id1-mediated augmentation of Treg cell levels on cellular immunity.
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Affiliation(s)
- Chen Liu
- Department of Immunology, Peking University Health Science Center, Beijing, China
| | | | - Sen Yu
- Department of Immunology, Peking University Health Science Center, Beijing, China
| | - Rong Jin
- Department of Immunology, Peking University Health Science Center, Beijing, China
| | - Hui Tang
- Department of Immunology, Peking University Health Science Center, Beijing, China
| | - Yuan-Feng Liu
- Department of Immunology, Peking University Health Science Center, Beijing, China
| | - Qing Ge
- Department of Immunology, Peking University Health Science Center, Beijing, China
| | - Xiao-Hong Sun
- Oklahoma Medical Research Foundation, Oklahoma City, OK
| | - Yu Zhang
- Department of Immunology, Peking University Health Science Center, Beijing, China
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179
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Salisbury EM, Wang L, Choi O, Rutschmann S, Ashton-Rickardt PG. N-Ethyl-N-nitrosourea mutagenesis in the mouse provides strong genetic and in vivo evidence for the role of the Caspase Recruitment Domain (CARD) of CARD-MAGUK1 in T regulatory cell development. Immunology 2014; 141:446-56. [PMID: 24383645 DOI: 10.1111/imm.12207] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2013] [Revised: 10/28/2013] [Accepted: 10/28/2013] [Indexed: 01/07/2023] Open
Abstract
Natural regulatory T (nTreg) cells generated in the thymus are essential throughout life for the maintenance of T-cell homeostasis and the prevention of autoimmunity. T-cell receptor (TCR)/CD28-mediated activation of nuclear factor-κB and (J)un (N)-terminal kinase pathways is known to play a key role in nTreg cell development but many of the predicted molecular interactions are based on extrapolations from non-Treg cell TCR stimulation with non-physiological ligands. For the first time, we provide strong genetic evidence of a scaffold function for the Caspase Recruitment Domain (CARD) of the TCR signalling protein CARD-MAGUK1 (CARMA1) in nTreg cell development in vivo. We report two, new, N-ethyl-N-nitrosourea-derived mutant mice, Vulpo and Zerda, with a profound block in the development of nTreg cells in the thymus as well as impaired inducible Treg cell differentiation in the periphery. Despite independent heritage, both mutants harbour different point mutations in the CARD of the CARMA1 protein. Mutations in vulpo and zerda do not affect expression levels of CARMA1 but still impair signalling through the TCR due to defective downstream Bcl-10 recruitment by the mutated CARD of CARMA1. Phenotypic differences observed between Vulpo and Zerda mutants suggest a role for the CARD of CARMA1 independent of Bcl-10 activation of downstream pathways. We conclude that our forward genetic approach demonstrates a critical role for the CARD function of CARMA1 in Treg cell development in vivo.
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Affiliation(s)
- Emma M Salisbury
- Section of Immunobiology, Division of Immunology and Inflammation, Department of Medicine, Faculty of Medicine, Imperial College London, London, UK
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180
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Attridge K, Walker LSK. Homeostasis and function of regulatory T cells (Tregs) in vivo: lessons from TCR-transgenic Tregs. Immunol Rev 2014; 259:23-39. [PMID: 24712457 PMCID: PMC4237543 DOI: 10.1111/imr.12165] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The identification of CD25 and subsequently Forkhead box protein 3 (Foxp3) as markers for regulatory T cells (Tregs) has revolutionized our ability to explore this population experimentally. In a similar vein, our understanding of antigen-specific Treg responses in vivo owes much to the fortuitous generation of T-cell receptor (TCR)-transgenic Tregs. This has permitted tracking of Tregs with a defined specificity in vivo, facilitating analysis of how encounter with cognate antigen shapes Treg homeostasis and function. Here, we review the key lessons learned from a decade of analysis of TCR-transgenic Tregs and set this in the broader context of general progress in the field. Use of TCR-transgenic Tregs has led to an appreciation that Tregs are a highly dynamic proliferative population in vivo, rather than an anergic population as they were initially portrayed. It is now clear that Treg homeostasis is positively regulated by encounter with self-antigen expressed on peripheral tissues, which is likely to be relevant to the phenomenon of peripheral repertoire reshaping that has been described for Tregs and the observation that the Treg TCR specificities vary by anatomical location. Substantial evidence has also accumulated to support the role of CD28 costimulation and interleukin-2 in Treg homeostasis. The availability of TCR-transgenic Tregs has enabled analysis of Treg populations that are sufficient or deficient in particular genes, without the comparison being confounded by repertoire alterations. This approach has yielded insights into genes required for Treg function in vivo, with particular progress being made on the role of ctla-4 in this context. As the prospect of manipulating Treg populations in the clinic becomes reality, a full appreciation of the rules governing their homeostasis will prove increasingly important.
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Affiliation(s)
- Kesley Attridge
- Kennedy Institute of Rheumatology, University of Oxford, Oxford, UK
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181
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Pellerin L, Jenks JA, Bégin P, Bacchetta R, Nadeau KC. Regulatory T cells and their roles in immune dysregulation and allergy. Immunol Res 2014; 58:358-68. [PMID: 24781194 PMCID: PMC4161462 DOI: 10.1007/s12026-014-8512-5] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The main function of the immune system is to fight off potential infections, but also to maintain its activity below a level that would trigger self-reactivity. Regulatory T cells (Tregs) such as forkhead box P3(+) (FOXP3) Tregs and type 1 regulatory T cells (Tr1) play an essential role in this active process, using several distinct suppressive mechanisms. A wide range of pathologies have been associated with altered Treg cell function. This is best exemplified by the impact of mutations of genes essential for Treg function and the associated autoimmune syndromes. This review summarizes the main features of different subtypes of Tregs and focuses on the clinical implications of their altered function in human studies. More specifically, we discuss abnormalities affecting FOXP3(+) Tregs and Tr1 cells that will lead to autoimmune manifestations and/or allergic reactions, and the potential therapeutic use of Tregs.
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Affiliation(s)
- Laurence Pellerin
- Division of Pediatric Immunology and Allergy, Stanford University, Stanford, CA 94305, USA
| | - Jennifer A. Jenks
- Division of Pediatric Immunology and Allergy, Stanford University, Stanford, CA 94305, USA
| | - Philippe Bégin
- Division of Pediatric Immunology and Allergy, Stanford University, Stanford, CA 94305, USA
| | - Rosa Bacchetta
- Division of Pediatric Immunology and Allergy, Stanford University, Stanford, CA 94305, USA
| | - Kari C. Nadeau
- Division of Pediatric Immunology and Allergy, Stanford University, Stanford, CA 94305, USA
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182
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Abstract
Foxp3(+) T-regulatory cells (Tregs) are primarily generated in the thymus (tTreg), but also may be generated extrathymically at peripheral sites (pTreg), or induced in cell culture (iTreg) in the presence of transforming growth factor β (TGFβ). A major unresolved issue is how these different populations of Tregs exert their suppressive function in vivo. We have developed novel systems in which the function of Tregs can be evaluated in vivo in normal mice. Our studies demonstrate that one prominent mechanism of action of polyclonal tTregs is to inhibit T-effector cell trafficking to the target organ, while antigen-specific iTregs primarily prevent T-cell priming by acting on antigen-presenting dendritic cells (DCs). Interleukin-10 (IL-10) plays an important role in the suppressive function of antigen-specific iTregs by controlling the expression of MARCH1 and CD83 on the DC. Activated tTregs may mediate infectious tolerance by delivery of cell surface-expressed TGFβ to naive responder T cells to generate pTregs. Manipulation of Treg function will require the ability to differentiate tTregs from pTregs and iTregs. The expression of the transcription factor Helios has proven to be a useful marker for the identification of stable tTregs in both mouse and human.
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Affiliation(s)
- Ethan M Shevach
- Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institute of Health, Bethesda, MD, USA
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183
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Lane PJL, McConnell FM, Anderson G, Nawaf MG, Gaspal FM, Withers DR. Evolving strategies for cancer and autoimmunity: back to the future. Front Immunol 2014; 5:154. [PMID: 24782861 PMCID: PMC3995051 DOI: 10.3389/fimmu.2014.00154] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Accepted: 03/24/2014] [Indexed: 11/24/2022] Open
Abstract
Although current thinking has focused on genetic variation between individuals and environmental influences as underpinning susceptibility to both autoimmunity and cancer, an alternative view is that human susceptibility to these diseases is a consequence of the way the immune system evolved. It is important to remember that the immunological genes that we inherit and the systems that they control were shaped by the drive for reproductive success rather than for individual survival. It is our view that human susceptibility to autoimmunity and cancer is the evolutionarily acceptable side effect of the immune adaptations that evolved in early placental mammals to accommodate a fundamental change in reproductive strategy. Studies of immune function in mammals show that high affinity antibodies and CD4 memory, along with its regulation, co-evolved with placentation. By dissection of the immunologically active genes and proteins that evolved to regulate this step change in the mammalian immune system, clues have emerged that may reveal ways of de-tuning both effector and regulatory arms of the immune system to abrogate autoimmune responses whilst preserving protection against infection. Paradoxically, it appears that such a detuned and deregulated immune system is much better equipped to mount anti-tumor immune responses against cancers.
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Affiliation(s)
- Peter J L Lane
- MRC Centre for immune Regulation, Birmingham Medical School , Birmingham , UK
| | - Fiona M McConnell
- MRC Centre for immune Regulation, Birmingham Medical School , Birmingham , UK
| | - Graham Anderson
- MRC Centre for immune Regulation, Birmingham Medical School , Birmingham , UK
| | - Maher G Nawaf
- MRC Centre for immune Regulation, Birmingham Medical School , Birmingham , UK
| | - Fabrina M Gaspal
- MRC Centre for immune Regulation, Birmingham Medical School , Birmingham , UK
| | - David R Withers
- MRC Centre for immune Regulation, Birmingham Medical School , Birmingham , UK
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184
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Costimulation via the tumor-necrosis factor receptor superfamily couples TCR signal strength to the thymic differentiation of regulatory T cells. Nat Immunol 2014; 15:473-81. [PMID: 24633226 PMCID: PMC4000541 DOI: 10.1038/ni.2849] [Citation(s) in RCA: 212] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2013] [Accepted: 02/21/2014] [Indexed: 12/12/2022]
Abstract
Regulatory T (Treg) cells express tumor necrosis factor receptor superfamily (TNFRSF) members, but their role in thymic Treg development is undefined. We demonstrate that Treg progenitors highly express the TNFRSF members GITR, OX40, and TNFR2. Expression of these receptors correlates directly with T cell receptor (TCR) signal strength, and requires CD28 and the kinase TAK1. Neutralizing TNFSF ligands markedly reduced Treg development. Conversely, TNFRSF agonists enhanced Treg differentiation by augmenting IL-2R/STAT5 responsiveness. GITR-ligand costimulation elicited a dose-dependent enrichment of lower-affinity cells within the Treg repertoire. In vivo, combined inhibition of GITR, OX40 and TNFR2 abrogated Treg development. Thus TNFRSF expression on Treg progenitors translates strong TCR signals into molecular parameters that specifically promote Treg differentiation and shape the Treg repertoire.
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185
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Yan F, Cai L, Hui Y, chen S, Meng H, Huang Z. Tolerogenic dendritic cells suppress murine corneal allograft rejection by modulating CD28/CTLA-4 expression on regulatory T cells. Cell Biol Int 2014; 38:835-48. [PMID: 24604878 DOI: 10.1002/cbin.10268] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Accepted: 02/21/2014] [Indexed: 12/21/2022]
Affiliation(s)
- Feng Yan
- Department of Ophthalmology; Jinling Hospital; School of Medicine; Nanjing University; Nanjing 210002 China
- Department of Ophthalmology; Xijing Hospital; The Fourth Military Medical University; Xi'an China
| | - Li Cai
- Department of Ophthalmology; Xijing Hospital; The Fourth Military Medical University; Xi'an China
| | - Yannian Hui
- Department of Ophthalmology; Xijing Hospital; The Fourth Military Medical University; Xi'an China
| | - Suihua chen
- Department of Ophthalmology; Jinling Hospital; School of Medicine; Nanjing University; Nanjing 210002 China
| | - Hao Meng
- Department of Ophthalmology; Xijing Hospital; The Fourth Military Medical University; Xi'an China
- Department of Ophthalmology; NO.313 Hospital; Hulu Dao China
| | - Zhenping Huang
- Department of Ophthalmology; Jinling Hospital; School of Medicine; Nanjing University; Nanjing 210002 China
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186
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Higo K, Oda M, Morii H, Takahashi J, Harada Y, Ogawa S, Abe R. Quantitative analysis by surface plasmon resonance of CD28 interaction with cytoplasmic adaptor molecules Grb2, Gads and p85 PI3K. Immunol Invest 2014; 43:278-91. [DOI: 10.3109/08820139.2013.875039] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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187
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Lee CN, Lew AM, Wu L. The potential role of dendritic cells in the therapy of Type 1 diabetes. Immunotherapy 2014; 5:591-606. [PMID: 23725283 DOI: 10.2217/imt.13.48] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Type 1 diabetes (T1D) is the result of T-cell mediated autoimmune destruction of pancreatic islet β-cells. The two current treatments for T1D are based on insulin or islet-cell replacement rather than the pathogenesis of T1D and remain problematic. Islet/pancreas transplantation does not cater for the majority of sufferers due to the lack of supply of organs and the need for continuous immunosuppression regimens. The mainstay treatment is insulin replacement, but this is disruptive to lifestyle and does not protect against severe long-term complications. An early vaccination and long-term restoration of immune tolerance to self-antigens in T1D patients (reversing the immunopathogenesis of the disease) would be preferable. Dendritic cells (DCs) are potent APCs and play an important role in inducing and maintaining immune tolerance. Targeting DCs through different DC surface molecules shows effective modulation of immune responses. Their feasibility for immunotherapy to prolong transplant survival and cancer immunotherapy has been demonstrated. Therefore, DCs could potentially be used in the treatment of autoimmune diseases. This review summarizes new insights into DCs as a potential therapeutic target for the treatment of T1D.
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Affiliation(s)
- Chin-Nien Lee
- Molecular Immunology Division, The Walter & Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia
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188
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Thymocyte apoptosis drives the intrathymic generation of regulatory T cells. Proc Natl Acad Sci U S A 2014; 111:E465-73. [PMID: 24474796 DOI: 10.1073/pnas.1320319111] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Maintenance of immune tolerance critically depends upon regulatory T cells that express the transcription factor forkhead box P3 (Foxp3). These CD4(+) T cells can be generated in the thymus, termed thymus-derived regulatory T cells (tTregs), but their developmental pathway remains incompletely understood. tTreg development has been shown to be delayed compared with that of CD4(+) single positive (SP) thymocytes, with tTregs being detected only in neonatal thymi by day 3 after birth. Here, we outline the reasons for this delayed emergence of Foxp3(+) tTregs and demonstrate that thymocyte apoptosis is intrinsically tied to tTreg development. We show that thymic apoptosis leads to the production of TGFβ intrathymically from thymic macrophages, dendritic cells, and epithelial cells. This TGFβ then induces foxp3 expression and drives tTreg generation. Thymocyte apoptosis has previously been shown to accelerate after birth, which drives increases in TGFβ in the neonatal thymus. We highlight a paucity of TGFβ in the neonatal thymus, accounting for the delayed development of tTregs compared with CD4(+) SP thymocytes. Importantly, we show that enhanced levels of apoptosis in the thymus result in an augmented tTreg population and, moreover, that decreasing thymic apoptosis results in reduced tTregs. In addition to this, we also show that T-cell receptor (TCR) signals of different affinity were all capable of driving tTreg development; however, to achieve this TGFβ signals must also be received concomitant with the TCR signal. Collectively, our results indicate that thymic apoptosis is a key event in tTreg generation and reveal a previously unrecognized apoptosis-TGFβ-Foxp3 axis that mediates the development of tTregs.
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189
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Affiliation(s)
- Xuguang Tai
- Experimental Immunology Branch; National Cancer Institute; National Institutes of Health; Bethesda, MD USA
| | - Alfred Singer
- Experimental Immunology Branch; National Cancer Institute; National Institutes of Health; Bethesda, MD USA
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190
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Piccioni M, Chen Z, Tsun A, Li B. Regulatory T-cell differentiation and their function in immune regulation. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 841:67-97. [PMID: 25261205 DOI: 10.1007/978-94-017-9487-9_4] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Regulatory T-cells (Treg) represent a subset of CD4+ T-cells characterized by high suppressive capacity, which can be generated in the thymus or induced in the periphery. The deleterious phenotype of the Scurfy mouse, which develops an X-linked lymphoproliferative disease resulting from defective T-cell tolerance, clearly demonstrates the importance of Treg cells for the maintenance of immune homeostasis. Although significant progress has been achieved, much information regarding the development, characteristics and function of Treg cells remain lacking. This chapter highlights the most recent discoveries in the field of Treg biology, focusing on the development and role of this cell subset in the maintenance of immune balance.
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Affiliation(s)
- Miranda Piccioni
- Key Laboratory of Molecular Virology and Immunology, Unit of Molecular Immunology, Institute Pasteur of Shanghai, Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200025, China
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191
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Delacher M, Schreiber L, Richards DM, Farah C, Feuerer M, Huehn J. Transcriptional control of regulatory T cells. Curr Top Microbiol Immunol 2014; 381:83-124. [PMID: 24831347 DOI: 10.1007/82_2014_373] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Regulatory T cells (Tregs) constitute unique T cell lineage that plays a key role for immunological tolerance. Tregs are characterized by the expression of the forkhead box transcription factor Foxp3, which acts as a lineage-specifying factor by determining the unique suppression profile of these immune cells. Here, we summarize the recent progress in understanding how Foxp3 expression itself is epigenetically and transcriptionally controlled, how the Treg-specific signature is achieved and how unique properties of Treg subsets are defined by other transcription factors. Finally, we will discuss recent studies focusing on the molecular targeting of Tregs to utilize the specific properties of this unique cell type in therapeutic settings.
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Affiliation(s)
- Michael Delacher
- Immune Tolerance, Tumor Immunology Program, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120, Heidelberg, Germany
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192
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Abstract
T cell activation is a key event in the adaptive immune response and vital to the generation of both cellular and humoral immunity. Activation is required not only for effective CD4 T cell responses but also to provide help for B cells and the generation of cytotoxic T cell responses. Unsurprisingly, impaired T cell activation results in infectious pathology, whereas dysregulated activation can result in autoimmunity. The decision to activate is therefore tightly regulated and the CD28/CTLA-4 pathway represents this apical decision point at the molecular level. In particular, CTLA-4 (CD152) is an essential checkpoint control for autoimmunity; however, the molecular mechanism(s) by which CTLA-4 achieves its regulatory function are not well understood, especially how it functionally intersects with the CD28 pathway. In this chapter, we review the established molecular and cellular concepts relating to CD28 and CTLA-4 biology, and attempt to integrate these by discussing the transendocytosis of ligands as a new model of CTLA-4 function.
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Affiliation(s)
- Blagoje Soskic
- School of Immunity and Infection, University of Birmingham, Birmingham, United Kingdom
| | | | - Tiezheng Hou
- UCL Institute of Immunity and Transplantation, Royal Free Campus, London, United Kingdom
| | - David M Sansom
- UCL Institute of Immunity and Transplantation, Royal Free Campus, London, United Kingdom.
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193
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Abstract
Regulatory T (Treg) cells, as central mediators of immune suppression, play crucial roles in many aspects of immune system's physiology and pathophysiology. The transcription factor Foxp3 has been characterized as a master gene of Tregs. Yet Treg cells possess a distinct pattern of gene expression, including upregulation of immune-suppressive genes and silencing of inflammatory cytokine genes. Recent studies have revealed the molecular mechanisms that establish and maintain such gene regulation in Treg cells. This review discusses recent progress in our understanding of molecular features of Treg cells, with particular attention to Treg-cell lineage commitment and stability.
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194
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Williams JA, Zhang J, Jeon H, Nitta T, Ohigashi I, Klug D, Kruhlak MJ, Choudhury B, Sharrow SO, Granger L, Adams A, Eckhaus MA, Jenkinson SR, Richie ER, Gress RE, Takahama Y, Hodes RJ. Thymic medullary epithelium and thymocyte self-tolerance require cooperation between CD28-CD80/86 and CD40-CD40L costimulatory pathways. THE JOURNAL OF IMMUNOLOGY 2013; 192:630-40. [PMID: 24337745 DOI: 10.4049/jimmunol.1302550] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
A critical process during thymic development of the T cell repertoire is the induction of self-tolerance. Tolerance in developing T cells is highly dependent on medullary thymic epithelial cells (mTEC), and mTEC development in turn requires signals from mature single-positive thymocytes, a bidirectional relationship termed thymus crosstalk. We show that CD28-CD80/86 and CD40-CD40L costimulatory interactions, which mediate negative selection and self-tolerance, upregulate expression of LTα, LTβ, and receptor activator for NF-κB in the thymus and are necessary for medullary development. Combined absence of CD28-CD80/86 and CD40-CD40L results in profound deficiency in mTEC development comparable to that observed in the absence of single-positive thymocytes. This requirement for costimulatory signaling is maintained even in a TCR transgenic model of high-affinity TCR-ligand interactions. CD4 thymocytes maturing in the altered thymic epithelial environment of CD40/CD80/86 knockout mice are highly autoreactive in vitro and are lethal in congenic adoptive transfer in vivo, demonstrating a critical role for these costimulatory pathways in self-tolerance as well as thymic epithelial development. These findings demonstrate that cooperativity between CD28-CD80/86 and CD40-CD40L pathways is required for normal medullary epithelium and for maintenance of self-tolerance in thymocyte development.
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Affiliation(s)
- Joy A Williams
- Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892
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195
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Schmidt AM, Zou T, Joshi RP, Leichner TM, Pimentel MA, Sommers CL, Kambayashi T. Diacylglycerol kinase ζ limits the generation of natural regulatory T cells. Sci Signal 2013; 6:ra101. [PMID: 24280042 DOI: 10.1126/scisignal.2004411] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Natural regulatory T (nT(reg)) cells are important for maintaining tolerance to self- and foreign antigens, and they are thought to develop from thymocytes that receive strong T cell receptor (TCR)-mediated signals in the thymus. TCR engagement leads to the activation of phospholipase C-γ1, which generates the lipid second messenger diacylglycerol (DAG) from phosphatidylinositol 4,5-bisphosphate. We used mice that lack the ζ isoform of DAG kinase (DGKζ), which metabolizes DAG to terminate its signaling, to enhance TCR-mediated signaling and identify critical signaling events in nT(reg) cell development. Loss of DGKζ resulted in increased numbers of thymic CD25(+)Foxp3(-)CD4(+) nT(reg) cell precursors and Foxp3(+)CD4(+) nT(reg) cells in a cell-autonomous manner. DGKζ-deficient T cells exhibited increased nuclear translocation of the nuclear factor κB subunit c-Rel, as well as enhanced extracellular signal-regulated kinase (ERK) phosphorylation in response to TCR stimulation, suggesting that these downstream pathways may contribute to nT(reg) cell development. Indeed, reducing c-Rel abundance or blocking ERK phosphorylation abrogated the increased generation of nTreg cells by DGKζ-deficient thymocytes. The extent of ERK phosphorylation correlated with TCR-mediated acquisition of Foxp3 in immature thymocytes in vitro. Furthermore, the development of nT(reg) cells was augmented in mice in which ERK activation was selectively enhanced in T cells. Together, these data suggest that DGKζ regulates the development of nT(reg) cells by limiting the extent of activation of the ERK and c-Rel signaling pathways.
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Affiliation(s)
- Amanda M Schmidt
- 1Department of Pathology and Laboratory Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 10194, USA
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196
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Caridade M, Graca L, Ribeiro RM. Mechanisms Underlying CD4+ Treg Immune Regulation in the Adult: From Experiments to Models. Front Immunol 2013; 4:378. [PMID: 24302924 PMCID: PMC3831161 DOI: 10.3389/fimmu.2013.00378] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Accepted: 11/03/2013] [Indexed: 12/29/2022] Open
Abstract
To maintain immunological balance the organism has to be tolerant to self while remaining competent to mount an effective immune response against third-party antigens. An important mechanism of this immune regulation involves the action of regulatory T-cell (Tregs). In this mini-review, we discuss some of the known and proposed mechanisms by which Tregs exert their influence in the context of immune regulation, and the contribution of mathematical modeling for these mechanistic studies. These models explore the mechanisms of action of regulatory T cells, and include hypotheses of multiple signals, delivered through simultaneous antigen-presenting cell (APC) conjugation; interaction of feedback loops between APC, Tregs, and effector cells; or production of specific cytokines that act on effector cells. As the field matures, and competing models are winnowed out, it is likely that we will be able to quantify how tolerance-inducing strategies, such as CD4-blockade, affect T-cell dynamics and what mechanisms explain the observed behavior of T-cell based tolerance.
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Affiliation(s)
- Marta Caridade
- Instituto de Medicina Molecular, Faculdade de Medicina da Universidade de Lisboa , Lisbon , Portugal ; Instituto Gulbenkian de Ciência , Oeiras , Portugal
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197
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Rojo JM, Ojeda G, Acosta YY, Montes-Casado M, Criado G, Portolés P. Characteristics of TCR/CD3 complex CD3{varepsilon} chains of regulatory CD4+ T (Treg) lymphocytes: role in Treg differentiation in vitro and impact on Treg in vivo. J Leukoc Biol 2013; 95:441-50. [PMID: 24212096 DOI: 10.1189/jlb.1112584] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Tregs are anergic CD4(+)CD25(+)Foxp3(+) T lymphocytes exerting active suppression to control immune and autoimmune responses. However, the factors in TCR recognition underlying Treg differentiation are unclear. Based on our previous data, we hypothesized that Treg TCR/CD3 antigen receptor complexes might differ from those of CD4(+)CD25(-) Tconv. Expression levels of TCR/CD3, CD3ε,ζ chains, or other molecules involved in antigen signaling and the characteristics of CD3ε chains were analyzed in thymus or spleen Treg cells from normal mice. Tregs had quantitative and qualitatively distinct TCR/CD3 complexes and CD3ε chains. They expressed significantly lower levels of the TCR/CD3 antigen receptor, CD3ε chains, TCR-ζ chain, or the CD4 coreceptor than Tconv. Levels of kinases, adaptor molecules involved in TCR signaling, and early downstream activation pathways were also lower in Tregs than in Tconv. Furthermore, TCR/CD3 complexes in Tregs were enriched in CD3ε chains conserving their N-terminal, negatively charged amino acid residues; this trait is linked to a higher activation threshold. Transfection of mutant CD3ε chains lacking these residues inhibited the differentiation of mature CD4(+)Foxp3(-) T lymphocytes into CD4(+)Foxp3(+) Tregs, and differences in CD3ε chain recognition by antibodies could be used to enrich for Tregs in vivo. Our results show quantitative and qualitative differences in the TCR/CD3 complex, supporting the hyporesponsive phenotype of Tregs concerning TCR/CD3 signals. These differences might reconcile avidity and flexible threshold models of Treg differentiation and be used to implement therapeutic approaches involving Treg manipulation.
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Affiliation(s)
- Jose M Rojo
- 2.Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu, 9, E-28040 Madrid, Spain.
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198
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Yamada T, Nanashima N, Akita M, Shimizu T, Miura T, Yamana D, Sawano T, Sakurai T, Tsuchida S. Lectin-like receptor Ly49s3 on dendritic cells contributes to the differentiation of regulatory T cells in the rat thymus. THE JOURNAL OF IMMUNOLOGY 2013; 191:3799-809. [PMID: 23997226 DOI: 10.4049/jimmunol.1203511] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Naturally occurring regulatory T cells (nTregs), important for immune regulation and the maintenance of self-tolerance, develop in the thymus. The Hirosaki hairless rat (HHR), derived from the Sprague-Dawley rat (SDR), was shown to have decreased peripheral lymphocyte number, small thymus, and leukocyte infiltration in its dermis. In the HHR thymus, the medulla was underdeveloped and nTreg number was decreased. Array comparative genome hybridization revealed the deletion of an NK cell lectin-like receptor gene, Ly49s3, detecting MHC class I molecules on target cells, in the chromosome 4q42 region in HHRs. The gene was expressed in thymic conventional dendritic cells (cDCs) in SDRs, but not in HHRs. When CD4-single-positive or CD4(+)CD8(-)CD25(-) thymocytes were cultured with thymic cDCs, the expression of nTreg marker genes was lower when these cells were from HHRs than from SDRs, suggesting that HHR cDCs are deficient in the ability to induce and maintain nTreg differentiation. Expression of the genes was recovered when Ly49s3 was expressed on HHR thymic cDCs. Expression levels of MHC class II genes, presumably from cDCs, were parallel to those of nTreg marker genes in mixed-cell cultures. However, in the presence of an anti-MHC class I Ab, blocking interaction between Ly49s3 and MHC class I molecules, the expression of the former genes was upregulated, whereas the latter was downregulated. These results suggest that Ly49s3 contributes to nTreg regulation along with MHC class II molecules, whose effects alone are insufficient, and loss of Ly49s3 from thymic cDCs is the reason for the nTreg deficiency in HHRs.
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Affiliation(s)
- Toshiyuki Yamada
- Department of Biochemistry and Genome Biology, Hirosaki University Graduate School of Medicine, Hirosaki 036-8562, Japan
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199
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Thymic regulatory T cell development: role of signalling pathways and transcription factors. Clin Dev Immunol 2013; 2013:617595. [PMID: 24187564 PMCID: PMC3803129 DOI: 10.1155/2013/617595] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Accepted: 08/21/2013] [Indexed: 01/07/2023]
Abstract
Regulatory T cells (Tregs) are a subset of CD4 T cells that are key mediators of immune tolerance. Most Tregs develop in the thymus. In this review we summarise recent findings on the role of diverse signalling pathways and downstream transcription factors in thymic Treg development.
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200
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Murray SE. Cell-intrinsic role for NF-kappa B-inducing kinase in peripheral maintenance but not thymic development of Foxp3+ regulatory T cells in mice. PLoS One 2013; 8:e76216. [PMID: 24073289 PMCID: PMC3779168 DOI: 10.1371/journal.pone.0076216] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Accepted: 08/21/2013] [Indexed: 11/18/2022] Open
Abstract
NF-κB inducing kinase (NIK, MAP3K14) is a key signaling molecule in non-canonical NF-κB activation, and NIK deficient mice have been instrumental in deciphering the immunologic role of this pathway. Global ablation of NIK prevents lymph node development, impairs thymic stromal development, and drastically reduces B cells. Despite altered thymic selection, T cell numbers are near normal in NIK deficient mice. The exception is CD4(+) regulatory T cells (Tregs), which are reduced in the thymus and periphery. Defects in thymic stroma are known to contribute to impaired Treg generation, but whether NIK also plays a cell intrinsic role in Tregs is unknown. Here, we compared intact mice with single and mixed BM chimeric mice to assess the intrinsic role of NIK in Treg generation and maintenance. We found that while NIK expression in stromal cells suffices for normal thymic Treg development, NIK is required cell-intrinsically to maintain peripheral Tregs. In addition, we unexpectedly discovered a cell-intrinsic role for NIK in memory phenotype conventional T cells that is masked in intact mice, but revealed in BM chimeras. These results demonstrate a novel role for NIK in peripheral regulatory and memory phenotype T cell homeostasis.
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Affiliation(s)
- Susan E. Murray
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, Oregon, United States of America
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