1
|
Han P, Zhang W, Wang D, Wu Y, Li X, Zhao S, Zhu M. Comparative transcriptome analysis of T lymphocyte subpopulations and identification of critical regulators defining porcine thymocyte identity. Front Immunol 2024; 15:1339787. [PMID: 38384475 PMCID: PMC10879363 DOI: 10.3389/fimmu.2024.1339787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Accepted: 01/18/2024] [Indexed: 02/23/2024] Open
Abstract
Introduction The development and migration of T cells in the thymus and peripheral tissues are crucial for maintaining adaptive immunity in mammals. However, the regulatory mechanisms underlying T cell development and thymocyte identity formation in pigs remain largely underexplored. Method Here, by integrating bulk and single-cell RNA-sequencing data, we investigated regulatory signatures of porcine thymus and lymph node T cells. Results The comparison of T cell subpopulations derived from porcine thymus and lymph nodes revealed that their transcriptomic differences were influenced more by tissue origin than by T cell phenotypes, and that lymph node cells exhibited greater transcriptional diversity than thymocytes. Through weighted gene co-expression network analysis (WGCNA), we identified the key modules and candidate hub genes regulating the heterogeneity of T cell subpopulations. Further, we integrated the porcine thymocyte dataset with peripheral blood mononuclear cell (PBMC) dataset to systematically compare transcriptomic differences between T cell types from different tissues. Based on single-cell datasets, we further identified the key transcription factors (TFs) responsible for maintaining porcine thymocyte identity and unveiled that these TFs coordinately regulated the entire T cell development process. Finally, we performed GWAS of cell type-specific differentially expressed genes (DEGs) and 30 complex traits, and found that the DEGs in thymus-related and peripheral blood-related cell types, especially CD4_SP cluster and CD8-related cluster, were significantly associated with pig productive and reproductive traits. Discussion Our findings provide an insight into T cell development and lay a foundation for further exploring the porcine immune system and genetic mechanisms underlying complex traits in pigs.
Collapse
Affiliation(s)
- Pingping Han
- Key Lab of Agricultural Animal Genetics, Breeding, and Reproduction of Ministry of Education, Huazhong Agricultural University, Wuhan, China
| | - Wei Zhang
- Key Lab of Agricultural Animal Genetics, Breeding, and Reproduction of Ministry of Education, Huazhong Agricultural University, Wuhan, China
| | - Daoyuan Wang
- Key Lab of Agricultural Animal Genetics, Breeding, and Reproduction of Ministry of Education, Huazhong Agricultural University, Wuhan, China
| | - Yalan Wu
- Key Lab of Agricultural Animal Genetics, Breeding, and Reproduction of Ministry of Education, Huazhong Agricultural University, Wuhan, China
| | - Xinyun Li
- Key Lab of Agricultural Animal Genetics, Breeding, and Reproduction of Ministry of Education, Huazhong Agricultural University, Wuhan, China
- The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China
| | - Shuhong Zhao
- Key Lab of Agricultural Animal Genetics, Breeding, and Reproduction of Ministry of Education, Huazhong Agricultural University, Wuhan, China
- The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China
| | - Mengjin Zhu
- Key Lab of Agricultural Animal Genetics, Breeding, and Reproduction of Ministry of Education, Huazhong Agricultural University, Wuhan, China
- The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China
| |
Collapse
|
2
|
Lombard-Vadnais F, Chabot-Roy G, Zahn A, Rodriguez Torres S, Di Noia JM, Melichar HJ, Lesage S. Activation-induced cytidine deaminase expression by thymic B cells promotes T-cell tolerance and limits autoimmunity. iScience 2022; 26:105852. [PMID: 36654860 PMCID: PMC9840937 DOI: 10.1016/j.isci.2022.105852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Revised: 11/24/2022] [Accepted: 12/19/2022] [Indexed: 12/24/2022] Open
Abstract
Elimination of self-reactive T cells in the thymus is critical to establish T-cell tolerance. A growing body of evidence suggests a role for thymic B cells in the elimination of self-reactive thymocytes. To specifically address the role of thymic B cells in central tolerance, we investigated the phenotype of thymic B cells in various mouse strains, including non-obese diabetic (NOD) mice, a model of autoimmune diabetes. We noted that isotype switching of NOD thymic B cells is reduced as compared to other, autoimmune-resistant, mouse strains. To determine the impact of B cell isotype switching on thymocyte selection and tolerance, we generated NOD.AID-/- mice. Diabetes incidence was enhanced in these mice. Moreover, we observed reduced clonal deletion and a resulting increase in self-reactive CD4+ T cells in NOD.AID-/- mice relative to NOD controls. Together, this study reveals that AID expression in thymic B cells contributes to T-cell tolerance.
Collapse
Affiliation(s)
- Félix Lombard-Vadnais
- Immunologie-oncologie, Centre de recherche de l’Hôpital Maisonneuve-Rosemont, Montréal, QC H1T 2M4, Canada,Department of Microbiology & Immunology, McGill University, Montreal, QC H3A 0G4, Canada
| | - Geneviève Chabot-Roy
- Immunologie-oncologie, Centre de recherche de l’Hôpital Maisonneuve-Rosemont, Montréal, QC H1T 2M4, Canada
| | - Astrid Zahn
- Unité de recherche en biologie moléculaire des cellules B, Institut de recherches cliniques de Montréal, Montréal, QC H2W 1R7, Canada
| | - Sahily Rodriguez Torres
- Immunologie-oncologie, Centre de recherche de l’Hôpital Maisonneuve-Rosemont, Montréal, QC H1T 2M4, Canada,Département de microbiologie, infectiologie et immunologie, Université de Montréal, Montréal, QC H3T 1J4, Canada
| | - Javier M. Di Noia
- Department of Microbiology & Immunology, McGill University, Montreal, QC H3A 0G4, Canada,Unité de recherche en biologie moléculaire des cellules B, Institut de recherches cliniques de Montréal, Montréal, QC H2W 1R7, Canada,Département de médecine, Université de Montréal, Montréal, QC H3T 1J4, Canada,Department of Experimental Medicine, McGill University, Montreal, QC H3A 0G4, Canada
| | - Heather J. Melichar
- Immunologie-oncologie, Centre de recherche de l’Hôpital Maisonneuve-Rosemont, Montréal, QC H1T 2M4, Canada,Département de médecine, Université de Montréal, Montréal, QC H3T 1J4, Canada,Corresponding author
| | - Sylvie Lesage
- Immunologie-oncologie, Centre de recherche de l’Hôpital Maisonneuve-Rosemont, Montréal, QC H1T 2M4, Canada,Département de microbiologie, infectiologie et immunologie, Université de Montréal, Montréal, QC H3T 1J4, Canada,Corresponding author
| |
Collapse
|
3
|
Fishman H, Madiwale S, Geron I, Bari V, Van Loocke W, Kirschenbaum Y, Ganmore I, Kugler E, Rein-Gil A, Friedlander G, Schiby G, Birger Y, Strehl S, Soulier J, Knoechel B, Ferrando A, Noy-Lotan S, Nagler A, Mulloy JC, Van Vlierberghe P, Izraeli S. ETV6-NCOA2 fusion induces T/myeloid mixed-phenotype leukemia through transformation of nonthymic hematopoietic progenitor cells. Blood 2022; 139:399-412. [PMID: 34624096 PMCID: PMC9906988 DOI: 10.1182/blood.2020010405] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2020] [Accepted: 09/26/2021] [Indexed: 01/05/2023] Open
Abstract
Mixed-phenotype acute leukemia is a rare subtype of leukemia in which both myeloid and lymphoid markers are co-expressed on the same malignant cells. The pathogenesis is largely unknown, and the treatment is challenging. We previously reported the specific association of the recurrent t(8;12)(q13;p13) chromosomal translocation that creates the ETV6-NCOA2 fusion with T/myeloid leukemias. Here we report that ETV6-NCOA2 initiates T/myeloid leukemia in preclinical models; ectopic expression of ETV6-NCOA2 in mouse bone marrow hematopoietic progenitors induced T/myeloid lymphoma accompanied by spontaneous Notch1-activating mutations. Similarly, cotransduction of human cord blood CD34+ progenitors with ETV6-NCOA2 and a nontransforming NOTCH1 mutant induced T/myeloid leukemia in immunodeficient mice; the immunophenotype and gene expression pattern were similar to those of patient-derived ETV6-NCOA2 leukemias. Mechanistically, we show that ETV6-NCOA2 forms a transcriptional complex with ETV6 and the histone acetyltransferase p300, leading to derepression of ETV6 target genes. The expression of ETV6-NCOA2 in human and mouse nonthymic hematopoietic progenitor cells induces transcriptional dysregulation, which activates a lymphoid program while failing to repress the expression of myeloid genes such as CSF1 and MEF2C. The ETV6-NCOA2 induced arrest at an early immature T-cell developmental stage. The additional acquisition of activating NOTCH1 mutations transforms the early immature ETV6-NCOA2 cells into T/myeloid leukemias. Here, we describe the first preclinical model to depict the initiation of T/myeloid leukemia by a specific somatic genetic aberration.
Collapse
Affiliation(s)
- Hila Fishman
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- Rina Zaizov Pediatric Hematology Oncology Division, Schneider Children's Medical Center of Israel, Petah Tikvah, Israel
| | - Shreyas Madiwale
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- Rina Zaizov Pediatric Hematology Oncology Division, Schneider Children's Medical Center of Israel, Petah Tikvah, Israel
| | - Ifat Geron
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- Rina Zaizov Pediatric Hematology Oncology Division, Schneider Children's Medical Center of Israel, Petah Tikvah, Israel
| | - Vase Bari
- Cancer and Blood Diseases Institute, Cincinnati Children's Hospital, Cincinnati, OH
| | - Wouter Van Loocke
- Department of Pediatrics and Genetics, Ghent University, Ghent, Belgium
| | - Yael Kirschenbaum
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- Cancer Research Center, Chaim Sheba Medical Center at Tel HaShomer, Ramat Gan, Israel
| | - Itamar Ganmore
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- Cancer Research Center, Chaim Sheba Medical Center at Tel HaShomer, Ramat Gan, Israel
| | - Eitan Kugler
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- Rina Zaizov Pediatric Hematology Oncology Division, Schneider Children's Medical Center of Israel, Petah Tikvah, Israel
| | - Avigail Rein-Gil
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- Rina Zaizov Pediatric Hematology Oncology Division, Schneider Children's Medical Center of Israel, Petah Tikvah, Israel
| | - Gilgi Friedlander
- The Mantoux Bioinformatics Institute of the Nancy and Stephen Grand Israel National Center for Personalized Medicine, Weizmann Institute of Science, Rehovot, Israel
| | - Ginette Schiby
- Institute for Pathology Laboratory, Hematology Institute, Chaim Sheba Medical Center at Tel HaShomer, Ramat Gan, Israel
| | - Yehudit Birger
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- Rina Zaizov Pediatric Hematology Oncology Division, Schneider Children's Medical Center of Israel, Petah Tikvah, Israel
| | - Sabine Strehl
- Children's Cancer Research Institute, St. Anna Kinderkrebsforschung, Vienna, Austria
| | - Jean Soulier
- Genomes and Cell Biology of Disease, Hôpital Saint-Louis, Paris, France
| | - Birgit Knoechel
- Dana-Farber Cancer Institute, Boston Children's Hospital, Boston, MA
| | - Adolfo Ferrando
- Institute for Cancer Genetics, Columbia University, New York, NY
| | - Sharon Noy-Lotan
- Rina Zaizov Pediatric Hematology Oncology Division, Schneider Children's Medical Center of Israel, Petah Tikvah, Israel
| | - Arnon Nagler
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- Hematology Division Bone Marrow Transplants and Cord-Blood Bank, Chaim Sheba Medical Center at Tel HaShomer, Ramat Gan, Israel
| | - James C. Mulloy
- Cancer and Blood Diseases Institute, Cincinnati Children's Hospital, Cincinnati, OH
| | | | - Shai Izraeli
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- Rina Zaizov Pediatric Hematology Oncology Division, Schneider Children's Medical Center of Israel, Petah Tikvah, Israel
- Department of System Biology, City of Hope, Duarte, CA
| |
Collapse
|
4
|
Dong M, Audiger C, Adegoke A, Lebel MÈ, Valbon SF, Anderson CC, Melichar HJ, Lesage S. CD5 levels reveal distinct basal T-cell receptor signals in T cells from non-obese diabetic mice. Immunol Cell Biol 2021; 99:656-667. [PMID: 33534942 DOI: 10.1111/imcb.12443] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 01/11/2021] [Accepted: 02/01/2021] [Indexed: 12/15/2022]
Abstract
Type 1 diabetes in non-obese diabetic (NOD) mice occurs when autoreactive T cells eliminate insulin producing pancreatic β cells. While extensively studied in T-cell receptor (TCR) transgenic mice, the contribution of alterations in thymic selection to the polyclonal T-cell pool in NOD mice is not yet resolved. The magnitude of signals downstream of TCR engagement with self-peptide directs the development of a functional T-cell pool, in part by ensuring tolerance to self. TCR interactions with self-peptide are also necessary for T-cell homeostasis in the peripheral lymphoid organs. To identify differences in TCR signal strength that accompany thymic selection and peripheral T-cell maintenance, we compared CD5 levels, a marker of basal TCR signal strength, on immature and mature T cells from autoimmune diabetes-prone NOD and -resistant B6 mice. The data suggest that there is no preferential selection of NOD thymocytes that perceive stronger TCR signals from self-peptide engagement. Instead, NOD mice have an MHC-dependent increase in CD4+ thymocytes and mature T cells that express lower levels of CD5. In contrast, T cell-intrinsic mechanisms lead to higher levels of CD5 on peripheral CD8+ T cells from NOD relative to B6 mice, suggesting that peripheral CD8+ T cells with higher basal TCR signals may have survival advantages in NOD mice. These differences in the T-cell pool in NOD mice may contribute to the development or progression of autoimmune diabetes.
Collapse
Affiliation(s)
- Mengqi Dong
- Immunology-Oncology Unit, Maisonneuve-Rosemont Hospital Research Center, Montréal, Québec, Canada.,Département de microbiologie, Infectiologie et Immunologie, Université de Montréal, Montréal, Québec, Canada
| | - Cindy Audiger
- Immunology-Oncology Unit, Maisonneuve-Rosemont Hospital Research Center, Montréal, Québec, Canada.,Département de microbiologie, Infectiologie et Immunologie, Université de Montréal, Montréal, Québec, Canada
| | - Adeolu Adegoke
- Departments of Surgery, Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Marie-Ève Lebel
- Immunology-Oncology Unit, Maisonneuve-Rosemont Hospital Research Center, Montréal, Québec, Canada.,Département de microbiologie, Infectiologie et Immunologie, Université de Montréal, Montréal, Québec, Canada
| | - Stefanie F Valbon
- Immunology-Oncology Unit, Maisonneuve-Rosemont Hospital Research Center, Montréal, Québec, Canada.,Département de microbiologie, Infectiologie et Immunologie, Université de Montréal, Montréal, Québec, Canada
| | - Colin C Anderson
- Departments of Surgery and Medical Microbiology & Immunology, Alberta Diabetes Institute, Alberta Transplant Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Heather J Melichar
- Immunology-Oncology Unit, Maisonneuve-Rosemont Hospital Research Center, Montréal, Québec, Canada.,Département de Médecine, Université de Montréal, Montréal, Québec, Canada
| | - Sylvie Lesage
- Immunology-Oncology Unit, Maisonneuve-Rosemont Hospital Research Center, Montréal, Québec, Canada.,Département de microbiologie, Infectiologie et Immunologie, Université de Montréal, Montréal, Québec, Canada
| |
Collapse
|
5
|
Collin R, Lombard-Vadnais F, Hillhouse EE, Lebel MÈ, Chabot-Roy G, Melichar HJ, Lesage S. MHC-Independent Thymic Selection of CD4 and CD8 Coreceptor Negative αβ T Cells. THE JOURNAL OF IMMUNOLOGY 2020; 205:133-142. [PMID: 32434937 DOI: 10.4049/jimmunol.2000156] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Accepted: 04/23/2020] [Indexed: 12/12/2022]
Abstract
It is becoming increasingly clear that unconventional T cell subsets, such as NKT, γδ T, mucosal-associated invariant T, and CD8αα T cells, each play distinct roles in the immune response. Subsets of these cell types can lack both CD4 and CD8 coreceptor expression. Beyond these known subsets, we identify CD4-CD8-TCRαβ+, double-negative (DN) T cells, in mouse secondary lymphoid organs. DN T cells are a unique unconventional thymic-derived T cell subset. In contrast to CD5high DN thymocytes that preferentially yield TCRαβ+ CD8αα intestinal lymphocytes, we find that mature CD5low DN thymocytes are precursors to peripheral DN T cells. Using reporter mouse strains, we show that DN T cells transit through the immature CD4+CD8+ (double-positive) thymocyte stage. Moreover, we provide evidence that DN T cells can differentiate in MHC-deficient mice. Our study demonstrates that MHC-independent thymic selection can yield DN T cells that are distinct from NKT, γδ T, mucosal-associated invariant T, and CD8αα T cells.
Collapse
Affiliation(s)
- Roxanne Collin
- Immunology-Oncology Section, Maisonneuve-Rosemont Hospital Research Center, Montreal, Quebec H1T 2M4, Canada.,Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Quebec H3C 3J7, Canada
| | - Félix Lombard-Vadnais
- Immunology-Oncology Section, Maisonneuve-Rosemont Hospital Research Center, Montreal, Quebec H1T 2M4, Canada.,Department of Microbiology and Immunology, McGill University, Montreal, Quebec H3A 0G4, Canada; and
| | - Erin E Hillhouse
- Immunology-Oncology Section, Maisonneuve-Rosemont Hospital Research Center, Montreal, Quebec H1T 2M4, Canada
| | - Marie-Ève Lebel
- Immunology-Oncology Section, Maisonneuve-Rosemont Hospital Research Center, Montreal, Quebec H1T 2M4, Canada
| | - Geneviève Chabot-Roy
- Immunology-Oncology Section, Maisonneuve-Rosemont Hospital Research Center, Montreal, Quebec H1T 2M4, Canada
| | - Heather J Melichar
- Immunology-Oncology Section, Maisonneuve-Rosemont Hospital Research Center, Montreal, Quebec H1T 2M4, Canada.,Département de Médecine, Université de Montréal, Montreal, Quebec H3T 1J4, Canada
| | - Sylvie Lesage
- Immunology-Oncology Section, Maisonneuve-Rosemont Hospital Research Center, Montreal, Quebec H1T 2M4, Canada; .,Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Quebec H3C 3J7, Canada
| |
Collapse
|
6
|
Toshima K, Nagafuku M, Okazaki T, Kobayashi T, Inokuchi JI. Plasma membrane sphingomyelin modulates thymocyte development by inhibiting TCR-induced apoptosis. Int Immunol 2020; 31:211-223. [PMID: 30561621 DOI: 10.1093/intimm/dxy082] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Accepted: 12/12/2019] [Indexed: 12/18/2022] Open
Abstract
Sphingomyelin (SM) in combination with cholesterol forms specialized membrane lipid microdomains in which specific receptors and signaling molecules are localized or recruited to mediate intracellular signaling. SM-microdomain levels in mouse thymus were low in the early CD4+CD8+ double-positive (DP) stage prior to thymic selection and increased >10-fold during late selection. T-cell receptor (TCR) signal strength is a key factor determining whether DP thymocytes undergo positive or negative selection. We examined the role of SM-microdomains in thymocyte development and related TCR signaling, using SM synthase 1 (SMS1)-deficient (SMS1-/-) mice which display low SM expression in all thymocyte populations. SMS1 deficiency caused reduced cell numbers after late DP stages in TCR transgenic models. TCR-dependent apoptosis induced by anti-CD3 treatment was enhanced in SMS1-/- DP thymocytes both in vivo and in vitro. SMS1-/- DP thymocytes, relative to controls, showed increased phosphorylation of TCR-proximal kinase ZAP-70 and increased expression of Bim and Nur77 proteins involved in negative selection following TCR stimulation. Addition of SM to cultured normal DP thymocytes led to greatly increased surface expression of SM-microdomains, with associated reduction of TCR signaling and TCR-induced apoptosis. Our findings indicate that SM-microdomains are increased in late DP stages, function as negative regulators of TCR signaling and modulate the efficiency of TCR-proximal signaling to promote thymic selection events leading to subsequent developmental stages.
Collapse
Affiliation(s)
- Kaoru Toshima
- Division of Glycopathology, Institute of Molecular Biomembrane and Glycobiology, Tohoku Medical and Pharmaceutical University, Aoba-ku, Sendai, Miyagi, Japan
| | - Masakazu Nagafuku
- Division of Glycopathology, Institute of Molecular Biomembrane and Glycobiology, Tohoku Medical and Pharmaceutical University, Aoba-ku, Sendai, Miyagi, Japan
| | - Toshiro Okazaki
- Department of Hematology and Immunology, Kanazawa Medical University, Uchinada, Ishikawa, Japan
| | | | - Jin-Ichi Inokuchi
- Division of Glycopathology, Institute of Molecular Biomembrane and Glycobiology, Tohoku Medical and Pharmaceutical University, Aoba-ku, Sendai, Miyagi, Japan
| |
Collapse
|
7
|
Abstract
Thymic negative selection is a process that aims to eliminate autoreactive T cells by inducing the apoptosis of thymocytes expressing a T-cell receptor (TCR) with high affinity for self-MHC. In this issue, Trinquand and colleagues demonstrate that TCR engagement or anti-CD3 stimulation of TCR-expressing T acute lymphoblastic leukemia cells results in their apoptosis. This cell death is reminiscent of thymic negative selection and has the potential for therapeutic exploitation. Cancer Discov; 6(9); 946-8. ©2016 AACR.See related article by Trinquand et al., p. 972.
Collapse
Affiliation(s)
- François Lemonnier
- Campbell Family Institute for Breast Cancer Research at the Princess Margaret Cancer Centre, University Health Network, Toronto, Canada
| | - Tak W Mak
- Campbell Family Institute for Breast Cancer Research at the Princess Margaret Cancer Centre, University Health Network, Toronto, Canada. Department of Medical Biophysics, University of Toronto, University Health Network, Toronto, Canada.
| |
Collapse
|
8
|
HDAC4 is expressed on multiple T cell lineages but dispensable for their development and function. Oncotarget 2017; 8:17562-17572. [PMID: 28177888 PMCID: PMC5392269 DOI: 10.18632/oncotarget.15077] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Accepted: 01/11/2017] [Indexed: 01/08/2023] Open
Abstract
Histone deacetylation, reciprocally mediated by histone deacetylases (HDAC) and acetyltransferases, represents one major form of post-translational modification. Previous research indicates that HDACs play an essential regulatory role in the development of various immune cells. However, the specific function of individual HDACs remains largely unexplored. HDAC4, a member of class II HDACs, profoundly investigated in the nervous system, while the expression profile and function of HDAC4 in T cells are barely known. For the first time, we report here that HDAC4 is expressed in the multiple T cell lineages. Using T-cell-specific HDAC4-deficient mice, we discovered that lack of HDAC4 did not alter the frequencies of conventional T cells, invariant NKT (iNKT) cells or regulatory T cells within both the thymus and secondary lymphoid organs. Moreover, conventional T cells and iNKT cells from wild-type and HDAC4-deficient mice displayed no significant difference in cytokine production. In conclusion, our results imply that under steady stage, HDAC4 is not required for the development and function of multiple T cell lineages, including conventional T cells and iNKT cells.
Collapse
|
9
|
Audiger C, Rahman MJ, Yun TJ, Tarbell KV, Lesage S. The Importance of Dendritic Cells in Maintaining Immune Tolerance. THE JOURNAL OF IMMUNOLOGY 2017; 198:2223-2231. [PMID: 28264998 DOI: 10.4049/jimmunol.1601629] [Citation(s) in RCA: 189] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Accepted: 12/11/2016] [Indexed: 12/30/2022]
Abstract
Immune tolerance is necessary to prevent the immune system from reacting against self, and thus to avoid the development of autoimmune diseases. In this review, we discuss key findings that position dendritic cells (DCs) as critical modulators of both thymic and peripheral immune tolerance. Although DCs are important for inducing both immunity and tolerance, increased autoimmunity associated with decreased DCs suggests their nonredundant role in tolerance induction. DC-mediated T cell immune tolerance is an active process that is influenced by genetic variants, environmental signals, as well as the nature of the specific DC subset presenting Ag to T cells. Answering the many open questions with regard to the role of DCs in immune tolerance could lead to the development of novel therapies for the prevention of autoimmune diseases.
Collapse
Affiliation(s)
- Cindy Audiger
- Department of Immunology-Oncology, Maisonneuve-Rosemont Hospital, Montreal, Quebec H1T 2M4, Canada.,Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Quebec H3C 3J7, Canada
| | - M Jubayer Rahman
- Immune Tolerance Section, Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Tae Jin Yun
- Laboratory of Cellular Physiology and Immunology, Clinical Research Institute of Montreal, Montreal, Quebec H2W 1R7, Canada; and.,Division of Experimental Medicine, Department of Medicine, McGill University, Montreal, Quebec H3A 1A3, Canada
| | - Kristin V Tarbell
- Immune Tolerance Section, Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Sylvie Lesage
- Department of Immunology-Oncology, Maisonneuve-Rosemont Hospital, Montreal, Quebec H1T 2M4, Canada; .,Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Quebec H3C 3J7, Canada
| |
Collapse
|
10
|
Sirois J, Daudelin JF, Boulet S, Marquis M, Meloche S, Labrecque N. The atypical MAPK ERK3 controls positive selection of thymocytes. Immunology 2015; 145:161-9. [PMID: 25521218 DOI: 10.1111/imm.12433] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Revised: 12/09/2014] [Accepted: 12/15/2014] [Indexed: 12/30/2022] Open
Abstract
Extracellular signal-regulated kinase 3 (ERK3 )is an atypical member of the mitogen-activated protein kinase (MAPK) family. We have previously shown that ERK3 is expressed during thymocyte differentiation and that its expression is induced in mature peripheral T cells following activation of ERK1/2 by T-cell receptor (TCR) signalling. Herein, we have investigated whether ERK3 expression is required for proper T-cell selection. Using a knock-in mouse model in which the coding sequence of ERK3 is replaced by the gene encoding for the β-galactosidase reporter, we show that ERK3 is expressed by double-positive (DP) thymocytes undergoing positive selection. In ERK3-deficient mice with a polyclonal TCR repertoire, we observe a decrease in positive selection. This reduction in positive selection was also observed when ERK3-deficient mice were backcrossed to class I- and class II-restricted TCR transgenic mice. Furthermore, the response of DP thymocytes to in vitro TCR stimulation was strongly reduced in ERK3-deficient mice. Together, these results show that ERK3 expression following TCR signalling is critical for proper thymic positive selection.
Collapse
Affiliation(s)
- Julien Sirois
- Maisonneuve-Rosemont Hospital Research Centre, Montreal, QC, Canada; Department of Microbiology, Infection and Immunology, University of Montreal, Montreal, QC, Canada
| | | | | | | | | | | |
Collapse
|
11
|
Murray JS. Transposon-mediated death of an ancestral A-23-like allele: evolution of TCR-positioning motifs in the HLA-A lineage. Immunogenetics 2015; 67:473-6. [PMID: 26063599 DOI: 10.1007/s00251-015-0852-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Accepted: 06/01/2015] [Indexed: 10/23/2022]
Abstract
HLA-A alleles are characterized by tandem arginine and histidine/arginine motifs (i.e., R65 and H151R motifs) present on the α1- and α2-helix, respectively. In crystallographic structures, α/β T-cell receptors (TCR) contact both motifs and appear to be geometrically positioned for alloreactivity. Herein, bioinformatics of "dual-motif" MHC A-like alleles were investigated across phylogeny. While A-like alleles with the R65 motif are widespread, the H151R motif has segregated out of most species. Surprisingly, an uncharacterized orf in tarsiers (Loc-103275158) encodes R151 within a truncated A-23-like gene, which is in frame with short footprints of Tc5 and Tigger transposons (TE); the extant tarsier A-23 allele is totally missing exon-3 and part of exon-4; together, suggesting TE-mediated inactivation of an intact/ancestral A-23 allele. Since the only other (non-human) dual-motif A-like alleles are in gorilla, chimpanzee, and the Florida manatee, we speculate that dual-motif A alleles first emerged in the Afrotherian lineage and reappeared during the evolution of higher primates.
Collapse
Affiliation(s)
- Joseph S Murray
- Xenolaüs Genetics LLC, 10880 Wilshire Blvd., Suite 1101, Los Angeles, CA, 90024, USA,
| |
Collapse
|
12
|
Murray JS. An old Twist in HLA-A: CDR3α Hook up at an R65-joint. Front Immunol 2015; 6:268. [PMID: 26074926 PMCID: PMC4445401 DOI: 10.3389/fimmu.2015.00268] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Accepted: 05/14/2015] [Indexed: 11/30/2022] Open
Abstract
T-cell ontogeny optimizes the α/β T-cell receptor (TCR) repertoire for recognition of major histocompatibility complex (MHC) class-I/II genetic polymorphism, and co-evolution of TCR germline V-gene segments and the MHC must entail somatic diversity generated in the third complimentary determining regions (CDR3α/β); however, it is still not clear how. Herein, a conspicuous structural link between the V-Jα used by several different TCR [all in complex with the same MHC molecule (HLA-A2)], and a conserved MHC motif (a.a., R65-X-X-K-A-X-S-Q72) is described. We model this R65-joint in detail, and show that the same TCR’s CDR3α loop maintains its CDR2α loop at a distance of ~4 Å from polymorphic amino acid (a.a.) positions of the α-2 helix in all but one of the analyzed crystal structures. Indeed, the pitch of docked TCRs varies as their twist/tilt/sway maintains the R65-joint and peptide contacts. Thus, the R65-joint appears to have poised the HLA-A lineage toward alloreactivity.
Collapse
|
13
|
Serrano-Candelas E, Alemán-Muench G, Solé-Sánchez S, Aubareda A, Martínez-Høyer S, Adán J, Aranguren-Ibáñez Á, Pritchard MA, Soldevila G, Pérez-Riba M. RCAN 1 and 3 proteins regulate thymic positive selection. Biochem Biophys Res Commun 2015; 460:295-301. [PMID: 25783055 DOI: 10.1016/j.bbrc.2015.03.029] [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: 02/18/2015] [Accepted: 03/06/2015] [Indexed: 01/18/2023]
Abstract
Cooperation between calcineurin (CN)-NFATc and RAF-MEK-ERK signaling pathways is essential in thymocyte positive selection. It is known that the Regulators of Calcineurin (RCAN) proteins can act either facilitating or suppressing CN-dependent signaling events. Here, we show that RCAN genes are expressed in lymphoid tissues, and address the role of RCAN proteins in T cell development. Overexpression of human RCAN3 and RCAN1 can modulate T cell development by increasing positive selection-related surface markers, as well as the "Erk(hi) competence state" in double positive thymocytes, a characteristic molecular signature of positive selection, without affecting CN activity. We also found that RCAN1/3 interact with RAF kinases and CN in a non-exclusive manner. Our data suggests that the balance of RCAN interactions with CN and/or RAF kinases may influence T cell positive selection.
Collapse
Affiliation(s)
- Eva Serrano-Candelas
- Human Molecular Genetics Laboratory, Cell Signaling Unit, Bellvitge Biomedical Research Institute - IDIBELL, L'Hospitalet de Llobregat, Barcelona 08908, Spain
| | - Germán Alemán-Muench
- Departamento de Inmunología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad Universitaria, México DF 04510, Mexico
| | - Sònia Solé-Sánchez
- Human Molecular Genetics Laboratory, Cell Signaling Unit, Bellvitge Biomedical Research Institute - IDIBELL, L'Hospitalet de Llobregat, Barcelona 08908, Spain
| | - Anna Aubareda
- Human Molecular Genetics Laboratory, Cell Signaling Unit, Bellvitge Biomedical Research Institute - IDIBELL, L'Hospitalet de Llobregat, Barcelona 08908, Spain
| | - Sergio Martínez-Høyer
- Human Molecular Genetics Laboratory, Cell Signaling Unit, Bellvitge Biomedical Research Institute - IDIBELL, L'Hospitalet de Llobregat, Barcelona 08908, Spain
| | - Jaume Adán
- LEITAT Technological Center, Biomed Divison, Parc Científic de Barcelona, Barcelona 08028, Spain
| | - Álvaro Aranguren-Ibáñez
- Human Molecular Genetics Laboratory, Cell Signaling Unit, Bellvitge Biomedical Research Institute - IDIBELL, L'Hospitalet de Llobregat, Barcelona 08908, Spain
| | - Melanie A Pritchard
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria 3168, Australia
| | - Gloria Soldevila
- Departamento de Inmunología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad Universitaria, México DF 04510, Mexico.
| | - Mercè Pérez-Riba
- Human Molecular Genetics Laboratory, Cell Signaling Unit, Bellvitge Biomedical Research Institute - IDIBELL, L'Hospitalet de Llobregat, Barcelona 08908, Spain.
| |
Collapse
|
14
|
The catalytic activity of the mitogen-activated protein kinase extracellular signal-regulated kinase 3 is required to sustain CD4+ CD8+ thymocyte survival. Mol Cell Biol 2014; 34:3374-87. [PMID: 25002529 DOI: 10.1128/mcb.01701-13] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Extracellular signal-regulated kinase 3 (ERK3) is an atypical member of the mitogen-activated protein kinase (MAPK) family whose function is largely unknown. Given the central role of MAPKs in T cell development, we hypothesized that ERK3 may regulate thymocyte development. Here we have shown that ERK3 deficiency leads to a 50% reduction in CD4(+) CD8(+) (DP) thymocyte number. Analysis of hematopoietic chimeras revealed that the reduction in DP thymocytes is intrinsic to hematopoietic cells. We found that early thymic progenitors seed the Erk3(-/-) thymus and can properly differentiate and proliferate to generate DP thymocytes. However, ERK3 deficiency results in a decrease in the DP thymocyte half-life, associated with a higher level of apoptosis. As a consequence, ERK3-deficient DP thymocytes are impaired in their ability to make successful secondary T cell receptor alpha (TCRα) gene rearrangement. Introduction of an already rearranged TCR transgene restores thymic cell number. We further show that knock-in of a catalytically inactive allele of Erk3 fails to rescue the loss of DP thymocytes. Our results uncover a unique role for ERK3, dependent on its kinase activity, during T cell development and show that this atypical MAPK is essential to sustain DP survival during RAG-mediated rearrangements.
Collapse
|
15
|
|
16
|
Dugas V, Chabot-Roy G, Beauchamp C, Guimont-Desrochers F, Hillhouse EE, Liston A, Lesage S. Unusual selection and peripheral homeostasis for immunoregulatory CD4(-) CD8(-) T cells. Immunology 2013; 139:129-39. [PMID: 23293940 DOI: 10.1111/imm.12064] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2012] [Revised: 12/21/2012] [Accepted: 01/03/2013] [Indexed: 11/27/2022] Open
Abstract
Immunoregulatory CD4(-) CD8(-) (double-negative; DN) T cells exhibit a unique antigen-specific mode of suppression, yet the ontogeny of DN T cells remains enigmatic. We have recently shown that 3A9 T-cell receptor (TCR) transgenic mice bear a high proportion of immunoregulatory 3A9 DN T cells, facilitating their study. The 3A9 TCR is positively selected on the H2(k) MHC haplotype, is negatively selected in mice bearing the cognate antigen, namely hen egg lysozyme, and there is absence of positive selection on the H2(b) MHC haplotype. Herein, we take advantage of this well-defined 3A9 TCR transgenic model to assess the thymic differentiation of DN T cells and its impact on determining the proportion of these cells in secondary lymphoid organs. We find that the proportion of DN T cells in the thymus is not dictated by the nature of the MHC-selecting haplotype. By defining DN T-cell differentiation in 3A9 TCR transgenic CD47-deficient mice as well as in mice bearing the NOD.H2(k) genetic background, we further demonstrate that the proportion of 3A9 DN T cells in the spleen is independent of the MHC selecting haplotype. Together, our findings suggest that immunoregulatory DN T cells are subject to rules distinct from those imposed upon CD4 T cells.
Collapse
Affiliation(s)
- Véronique Dugas
- Research Centre, Maisonneuve-Rosemont Hospital, Montreal, Quebec, Canada
| | | | | | | | | | | | | |
Collapse
|
17
|
Abstract
Abstract
The primary consequence of positive selection is to render thymocytes responsive to cytokines and chemokines expressed in the thymic medulla. In the present study, our main objective was to discover which cytokines could support the differentiation of positively selected thymocytes. To this end, we have developed an in vitro model suitable for high-throughput analyses of positive selection and CD8 T-cell differentiation. The model involves coculture of TCRhiCD5intCD69− double-positive (DP) thymocytes with peptide-pulsed OP9 cells and γc-cytokines. We report that IL-4, IL-7, and IL-21 have nonredundant effects on positively selected DP thymocytes. IL-7 signaling phosphorylates STAT5 and ERK; induces Foxo1, Klf2, and S1pr1; and supports the differentiation of classic CD8 T cells. IL-4 activates STAT6 and ERK and supports the differentiation of CD8intPD-L1hiCD44hiEOMES+ innate CD8 T cells. IL-21 is produced by thymic epithelial cells and the IL-21 receptor-α is strongly induced on DP thymocytes undergoing positive selection. IL-21 signaling phosphorylates STAT3 and STAT5, but not ERK, and does not support CD8 T-cell differentiation. However, IL-21 has a unique ability to up-regulate BCL-6, expand DP thymocytes undergoing positive selection, and increase the production of mature T cells. Our data suggest that injection of recombinant IL-21 might enhance thymic output in subjects with age- or disease-related thymic atrophy.
Collapse
|
18
|
Harada Y, Sawada H. Self-incompatibilty in gamete recognition: single self-recognizing determinants and multiple, non-self-recognizing ones function in the same individual. Mol Reprod Dev 2012. [PMID: 23184500 DOI: 10.1002/mrd.22134] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The frameworks (key mechanisms) of the self/non-self-discrimination systems that are found in various organisms have not been actively selected for, but have evolved by genetic drift such that the genetic frequency of random, advantageous mutations has increased within the genomes of these species by natural selection. The passive nature of this process leads to an important conclusion: in the self/non-self-discrimination system, the number of self-recognizing determinants becomes one compared to multiple non-self-recognizing determinants. Thus, the number of determinants is defined not by the character of the determinant, but by the system framework.
Collapse
Affiliation(s)
- Yoshito Harada
- Sugashima Marine Biological Laboratory, Graduate School of Science, Nagoya University, Sugashima, Toba, Japan.
| | | |
Collapse
|
19
|
Mittelstadt PR, Monteiro JP, Ashwell JD. Thymocyte responsiveness to endogenous glucocorticoids is required for immunological fitness. J Clin Invest 2012; 122:2384-94. [PMID: 22653054 DOI: 10.1172/jci63067] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2012] [Accepted: 04/18/2012] [Indexed: 12/21/2022] Open
Abstract
Generation of a self-tolerant but antigen-responsive T cell repertoire occurs in the thymus. Although glucocorticoids are usually considered immunosuppressive, there is also evidence that they play a positive role in thymocyte selection. To address the question of how endogenous glucocorticoids might influence the adaptive immune response, we generated GRlck-Cre mice, in which the glucocorticoid receptor gene (GR) is deleted in thymocytes prior to selection. These mice were immunocompromised, with reduced polyclonal T cell proliferative responses to alloantigen, defined peptide antigens, and viral infection. This was not due to an intrinsic proliferation defect, because GR-deficient T cells responded normally when the TCR was cross-linked with antibodies or when the T cell repertoire was "fixed" with αβ TCR transgenes. Varying the affinity of self ligands in αβ TCR transgenic mice showed that affinities that would normally lead to thymocyte-positive selection caused negative selection, and alterations in the TCR repertoire of polyclonal T cells were confirmed by analysis of TCR Vβ CDR3 regions. Thus, endogenous glucocorticoids are required for a robust adaptive immune response because of their promotion of the selection of T cells that have sufficient affinity for self, and the absence of thymocyte glucocorticoid signaling results in an immunocompromised state.
Collapse
Affiliation(s)
- Paul R Mittelstadt
- Laboratory of Immune Cell Biology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD, USA
| | | | | |
Collapse
|
20
|
Briones N, Dinu V. Data mining of high density genomic variant data for prediction of Alzheimer's disease risk. BMC MEDICAL GENETICS 2012; 13:7. [PMID: 22273362 PMCID: PMC3355044 DOI: 10.1186/1471-2350-13-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/22/2011] [Accepted: 01/25/2012] [Indexed: 11/25/2022]
Abstract
Background The discovery of genetic associations is an important factor in the understanding of human illness to derive disease pathways. Identifying multiple interacting genetic mutations associated with disease remains challenging in studying the etiology of complex diseases. And although recently new single nucleotide polymorphisms (SNPs) at genes implicated in immune response, cholesterol/lipid metabolism, and cell membrane processes have been confirmed by genome-wide association studies (GWAS) to be associated with late-onset Alzheimer's disease (LOAD), a percentage of AD heritability continues to be unexplained. We try to find other genetic variants that may influence LOAD risk utilizing data mining methods. Methods Two different approaches were devised to select SNPs associated with LOAD in a publicly available GWAS data set consisting of three cohorts. In both approaches, single-locus analysis (logistic regression) was conducted to filter the data with a less conservative p-value than the Bonferroni threshold; this resulted in a subset of SNPs used next in multi-locus analysis (random forest (RF)). In the second approach, we took into account prior biological knowledge, and performed sample stratification and linkage disequilibrium (LD) in addition to logistic regression analysis to preselect loci to input into the RF classifier construction step. Results The first approach gave 199 SNPs mostly associated with genes in calcium signaling, cell adhesion, endocytosis, immune response, and synaptic function. These SNPs together with APOE and GAB2 SNPs formed a predictive subset for LOAD status with an average error of 9.8% using 10-fold cross validation (CV) in RF modeling. Nineteen variants in LD with ST5, TRPC1, ATG10, ANO3, NDUFA12, and NISCH respectively, genes linked directly or indirectly with neurobiology, were identified with the second approach. These variants were part of a model that included APOE and GAB2 SNPs to predict LOAD risk which produced a 10-fold CV average error of 17.5% in the classification modeling. Conclusions With the two proposed approaches, we identified a large subset of SNPs in genes mostly clustered around specific pathways/functions and a smaller set of SNPs, within or in proximity to five genes not previously reported, that may be relevant for the prediction/understanding of AD.
Collapse
Affiliation(s)
- Natalia Briones
- Computational Biosciences Program, School of Mathematics and Statistical Sciences, Arizona State University, 1711 South Rural Road, Tempe, Arizona 85287-1804, USA
| | | |
Collapse
|
21
|
Proapoptotic protein Bim is differentially required during thymic clonal deletion to ubiquitous versus tissue-restricted antigens. Proc Natl Acad Sci U S A 2012; 109:893-8. [PMID: 22215602 DOI: 10.1073/pnas.1114834109] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Positive and negative selection of thymocytes in the thymus are critical for the development of a mature and self-tolerant T-cell repertoire. The proapoptotic Bcl-2 family member Bim is important for negative selection by inducing apoptosis in thymocytes receiving a strong signal through their antigen receptor. However, in the case of ubiquitous self-antigens (UbA), Bim is not required for the clonal deletion of self-reactive thymocytes, suggesting the existence of nonapoptotic clonal deletion mechanisms. Unlike UbA, clonal deletion to tissue-restricted antigens (TRAs) requires positive selection and CCR7-mediated migration to the medulla. This led us to hypothesize that Bim is required for the latter. To study the role of Bim in clonal deletion to TRA, we constructed bone marrow (BM) chimeras using OT-I Bim-deficient or -sufficient donor bone marrow and recipients that express membrane bound chicken ovalbumin under control of the rat insulin promoter (Rip-mOVA). We found that clonal deletion to TRA was completely abrogated in the absence of Bim and large numbers of mature OT-I CD8 T cells survived in the periphery. Despite the large numbers of autoreactive T cells, the chimeras did not develop diabetes and OT-I Bim-deficient T cells from these chimeras were functionally impaired. Collectively, these data provide unique evidence of a differential, thymocyte-intrinsic, molecular requirement downstream of the T-cell receptor (TCR) for clonal deletion to UbA versus TRA and highlight the profound ability of other tolerance mechanisms to control T-cell autoreactivity in the absence of thymic clonal deletion.
Collapse
|
22
|
Origin and plasticity of MHC I-associated self peptides. Autoimmun Rev 2011; 11:627-35. [PMID: 22100331 DOI: 10.1016/j.autrev.2011.11.003] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2011] [Accepted: 11/02/2011] [Indexed: 01/13/2023]
Abstract
Endogenous peptides presented by MHC I molecules represent the essence of self for CD8 T lymphocytes. These MHC I peptides (MIPs) regulate all key events that occur during the lifetime of CD8 T cells. CD8 T cells are selected on self-MIPs, sustained by self-MIPs, and activated in the presence of self-MIPs. Recently, large-scale mass spectrometry studies have revealed that the self-MIP repertoire is more complex and plastic than previously anticipated. The composition of the self-MIP repertoire varies from one cell type to another and can be perturbed by cell-intrinsic and -extrinsic factors including dysregulation of cellular metabolism and infection. The complexity and plasticity of the self-MIP repertoire represent a major challenge for the maintenance of self tolerance and can have pervasive effects on the global functioning of the immune system.
Collapse
|
23
|
Rafei M, Hardy MP, Williams P, Vanegas JR, Forner KA, Dulude G, Labrecque N, Galipeau J, Perreault C. Development and function of innate polyclonal TCRalphabeta+ CD8+ thymocytes. THE JOURNAL OF IMMUNOLOGY 2011; 187:3133-44. [PMID: 21844388 DOI: 10.4049/jimmunol.1101097] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Innate CD8 T cells are found in mutant mouse models, but whether they are produced in a normal thymus remains controversial. Using the RAG2p-GFP mouse model, we found that ∼10% of TCRαβ(+) CD4(-)CD8(+) thymocytes were innate polyclonal T cells (GFP(+)CD44(hi)). Relative to conventional T cells, innate CD8 thymocytes displayed increased cell surface amounts of B7-H1, CD2, CD5, CD38, IL-2Rβ, and IL-4Rα and downmodulation of TCRβ. Moreover, they overexpressed several transcripts, including T-bet, Id3, Klf2, and, most of all, Eomes. Innate CD8 thymocytes were positively selected, mainly by nonhematopoietic MHCIa(+) cells. They rapidly produced high levels of IFN-γ upon stimulation and readily proliferated in response to IL-2 and IL-4. Furthermore, low numbers of innate CD8 thymocytes were sufficient to help conventional CD8 T cells expand and secrete cytokine following Ag recognition. This helper effect depended on CD44-mediated interactions between innate and conventional CD8 T cells. We concluded that innate TCRαβ(+) CD8 T cells represent a sizeable proportion of normal thymocytes whose development and function differ in many ways from those of conventional CD8 T cells.
Collapse
Affiliation(s)
- Moutih Rafei
- Institute for Research in Immunology and Cancer, University of Montreal, Montreal, Quebec H3C 3J7, Canada
| | | | | | | | | | | | | | | | | |
Collapse
|