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Passos GA, Speck‐Hernandez CA, Assis AF, Mendes‐da‐Cruz DA. Update on Aire and thymic negative selection. Immunology 2018; 153:10-20. [PMID: 28871661 PMCID: PMC5721245 DOI: 10.1111/imm.12831] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Revised: 08/24/2017] [Accepted: 08/31/2017] [Indexed: 12/17/2022] Open
Abstract
Twenty years ago, the autoimmune regulator (Aire) gene was associated with autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy, and was cloned and sequenced. Its importance goes beyond its abstract link with human autoimmune disease. Aire identification opened new perspectives to better understand the molecular basis of central tolerance and self-non-self distinction, the main properties of the immune system. Since 1997, a growing number of immunologists and molecular geneticists have made important discoveries about the function of Aire, which is essentially a pleiotropic gene. Aire is one of the functional markers in medullary thymic epithelial cells (mTECs), controlling their differentiation and expression of peripheral tissue antigens (PTAs), mTEC-thymocyte adhesion and the expression of microRNAs, among other functions. With Aire, the immunological tolerance became even more apparent from the molecular genetics point of view. Currently, mTECs represent the most unusual cells because they express almost the entire functional genome but still maintain their identity. Due to the enormous diversity of PTAs, this uncommon gene expression pattern was termed promiscuous gene expression, the interpretation of which is essentially immunological - i.e. it is related to self-representation in the thymus. Therefore, this knowledge is strongly linked to the negative selection of autoreactive thymocytes. In this update, we focus on the most relevant results of Aire as a transcriptional and post-transcriptional controller of PTAs in mTECs, its mechanism of action, and its influence on the negative selection of autoreactive thymocytes as the bases of the induction of central tolerance and prevention of autoimmune diseases.
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Affiliation(s)
- Geraldo A. Passos
- Molecular Immunogenetics GroupDepartment of GeneticsRibeirão Preto Medical SchoolUniversity of São PauloRibeirão PretoSPBrazil
- Discipline of Genetics and Molecular BiologyDepartment of Morphology, Physiology and Basic PathologySchool of Dentistry of Ribeirão PretoUniversity of São PauloRibeirão PretoSPBrazil
| | - Cesar A. Speck‐Hernandez
- Graduate Programme in Basic and Applied ImmunologyRibeirão Preto Medical SchoolUniversity of São PauloRibeirão PretoSPBrazil
| | - Amanda F. Assis
- Molecular Immunogenetics GroupDepartment of GeneticsRibeirão Preto Medical SchoolUniversity of São PauloRibeirão PretoSPBrazil
| | - Daniella A. Mendes‐da‐Cruz
- Laboratory on Thymus ResearchOswaldo Cruz InstituteOswaldo Cruz FoundationRio de JaneiroRJBrazil
- National Institute of Science and Technology on NeuroimmunomodulationRio de JaneiroRJBrazil
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52
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Engelmann R, Biemelt A, Johl A, Kuthning D, Müller-Hilke B. Reduced Numbers of Mature Medullary Thymic Epithelial Cells in SKG Mice. Scand J Immunol 2017; 87:28-35. [PMID: 29105157 DOI: 10.1111/sji.12626] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Accepted: 10/25/2017] [Indexed: 11/27/2022]
Abstract
Attenuated T cell receptor (TCR) signalling contributes to the susceptibility for autoimmunity as shown via mutants of PTPN22 and Zap70 genes. We here set out to investigate the effect of an attenuated TCR signal on the composition of the thymic epithelial cell (TEC) compartment. To that extent, we combined flow cytometry and histology and compared the TEC subpopulations of Zap70 wild type with SKG mutant mice. We found an increased cortical TEC compartment in SKG thymi at the expense of reduced numbers of mature medullary TECs and a 4.8-fold reduced medulla area. We also found reduced proportions of CD69+ -activated thymocytes among double-negative, double-positive and CD4- CD8+ single-positive stages, reduced absolute numbers of single-positive thymocytes, diminished expression of Lta and Ltb by CD4- CD8+ single-positive thymocytes and a diminished expression of Ccl19, a target gene of the lymphotoxin-b-receptor. While the reduced thymocyte numbers together with the attenuated TCR signal explain the diminished expression of lymphotoxins, the latter is required for an AIRE-independent expression of tissue-restricted antigens as well as attracting positively selected thymocytes to the medulla. Our results describe altered TEC compartments in SKG mice that are likely to support the development of autoimmunity.
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Affiliation(s)
- R Engelmann
- AG Clinical Immunology, Institute of Immunology, Rostock University Medical Center, Rostock, Germany
| | - A Biemelt
- AG Clinical Immunology, Institute of Immunology, Rostock University Medical Center, Rostock, Germany
| | - A Johl
- AG Clinical Immunology, Institute of Immunology, Rostock University Medical Center, Rostock, Germany
| | - D Kuthning
- AG Clinical Immunology, Institute of Immunology, Rostock University Medical Center, Rostock, Germany
| | - B Müller-Hilke
- AG Clinical Immunology, Institute of Immunology, Rostock University Medical Center, Rostock, Germany
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53
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Takahama Y, Ohigashi I, Baik S, Anderson G. Generation of diversity in thymic epithelial cells. Nat Rev Immunol 2017; 17:295-305. [PMID: 28317923 DOI: 10.1038/nri.2017.12] [Citation(s) in RCA: 129] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
In the thymus, diverse populations of thymic epithelial cells (TECs), including cortical and medullary TECs and their subpopulations, have distinct roles in coordinating the development and repertoire selection of functionally competent and self-tolerant T cells. Here, we review the expanding diversity in TEC subpopulations in relation to their functions in T cell development and selection as well as their origins and development.
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Affiliation(s)
- Yousuke Takahama
- Division of Experimental Immunology, Institute of Advanced Medical Sciences, University of Tokushima, Tokushima 770-8503, Japan
| | - Izumi Ohigashi
- Division of Experimental Immunology, Institute of Advanced Medical Sciences, University of Tokushima, Tokushima 770-8503, Japan
| | - Song Baik
- Institute for Immunology and Immunotherapy, Medical School, University of Birmingham, Birmingham B15 2TT, UK
| | - Graham Anderson
- Institute for Immunology and Immunotherapy, Medical School, University of Birmingham, Birmingham B15 2TT, UK
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54
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Guha M, Saare M, Maslovskaja J, Kisand K, Liiv I, Haljasorg U, Tasa T, Metspalu A, Milani L, Peterson P. DNA breaks and chromatin structural changes enhance the transcription of autoimmune regulator target genes. J Biol Chem 2017; 292:6542-6554. [PMID: 28242760 PMCID: PMC5399106 DOI: 10.1074/jbc.m116.764704] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Revised: 01/30/2017] [Indexed: 12/22/2022] Open
Abstract
The autoimmune regulator (AIRE) protein is the key factor in thymic negative selection of autoreactive T cells by promoting the ectopic expression of tissue-specific genes in the thymic medullary epithelium. Mutations in AIRE cause a monogenic autoimmune disease called autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy. AIRE has been shown to promote DNA breaks via its interaction with topoisomerase 2 (TOP2). In this study, we investigated topoisomerase-induced DNA breaks and chromatin structural alterations in conjunction with AIRE-dependent gene expression. Using RNA sequencing, we found that inhibition of TOP2 religation activity by etoposide in AIRE-expressing cells had a synergistic effect on genes with low expression levels. AIRE-mediated transcription was not only enhanced by TOP2 inhibition but also by the TOP1 inhibitor camptothecin. The transcriptional activation was associated with structural rearrangements in chromatin, notably the accumulation of γH2AX and the exchange of histone H1 with HMGB1 at AIRE target gene promoters. In addition, we found the transcriptional up-regulation to co-occur with the chromatin structural changes within the genomic cluster of carcinoembryonic antigen-like cellular adhesion molecule genes. Overall, our results suggest that the presence of AIRE can trigger molecular events leading to an altered chromatin landscape and the enhanced transcription of low-expressed genes.
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Affiliation(s)
- Mithu Guha
- From the Molecular Pathology, Institute of Biomedical and Translational Medicine
| | - Mario Saare
- From the Molecular Pathology, Institute of Biomedical and Translational Medicine
| | - Julia Maslovskaja
- From the Molecular Pathology, Institute of Biomedical and Translational Medicine
| | - Kai Kisand
- From the Molecular Pathology, Institute of Biomedical and Translational Medicine
| | - Ingrid Liiv
- From the Molecular Pathology, Institute of Biomedical and Translational Medicine
| | - Uku Haljasorg
- From the Molecular Pathology, Institute of Biomedical and Translational Medicine
| | | | - Andres Metspalu
- Estonian Genome Center, and
- Institute of Molecular and Cell Biology, University of Tartu, Tartu 50411, Estonia
| | | | - Pärt Peterson
- From the Molecular Pathology, Institute of Biomedical and Translational Medicine,
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55
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Bansal K, Yoshida H, Benoist C, Mathis D. The transcriptional regulator Aire binds to and activates super-enhancers. Nat Immunol 2017; 18:263-273. [PMID: 28135252 PMCID: PMC5310976 DOI: 10.1038/ni.3675] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Accepted: 12/21/2016] [Indexed: 12/15/2022]
Abstract
Aire is a transcription factor that controls T cell tolerance by inducing the expression of a large repertoire of genes specifically in thymic stromal cells. It interacts with scores of protein partners of diverse functional classes. We found that Aire and some of its partners, notably those implicated in the DNA-damage response, preferentially localized to and activated long chromatin stretches that were overloaded with transcriptional regulators, known as super-enhancers. We also identified topoisomerase 1 as a cardinal Aire partner that colocalized on super-enhancers and was required for the interaction of Aire with all of its other associates. We propose a model that entails looping of super-enhancers to efficiently deliver Aire-containing complexes to local and distal transcriptional start sites.
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Affiliation(s)
- Kushagra Bansal
- Division of Immunology, Department of Microbiology and Immunobiology, Harvard Medical School, Boston MA 02115
| | - Hideyuki Yoshida
- Division of Immunology, Department of Microbiology and Immunobiology, Harvard Medical School, Boston MA 02115
| | - Christophe Benoist
- Division of Immunology, Department of Microbiology and Immunobiology, Harvard Medical School, Boston MA 02115
| | - Diane Mathis
- Division of Immunology, Department of Microbiology and Immunobiology, Harvard Medical School, Boston MA 02115
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56
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Romero P, Banchereau J, Bhardwaj N, Cockett M, Disis ML, Dranoff G, Gilboa E, Hammond SA, Hershberg R, Korman AJ, Kvistborg P, Melief C, Mellman I, Palucka AK, Redchenko I, Robins H, Sallusto F, Schenkelberg T, Schoenberger S, Sosman J, Türeci Ö, Van den Eynde B, Koff W, Coukos G. The Human Vaccines Project: A roadmap for cancer vaccine development. Sci Transl Med 2016; 8:334ps9. [PMID: 27075624 DOI: 10.1126/scitranslmed.aaf0685] [Citation(s) in RCA: 122] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Cancer vaccine development has been vigorously pursued for 40 years. Immunity to tumor antigens can be elicited by most vaccines tested, but their clinical efficacy remains modest. We argue that a concerted international effort is necessary to understand the human antitumor immune response and achieve clinically effective cancer vaccines.
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Affiliation(s)
- Pedro Romero
- Ludwig Cancer Research at University of Lausanne, 1066 Epalinges, Switzerland
| | | | - Nina Bhardwaj
- Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | | | - Mary L Disis
- University of Washington School of Medicine, Seattle, WA 98109-4714, USA
| | - Glenn Dranoff
- Novartis Institutes for Biomedical Research, Cambridge, MA 02139, USA
| | - Eli Gilboa
- Sylvester Comprehensive Cancer Center, Miami, FL 33136, USA
| | | | - Robert Hershberg
- Celgene Immuno-Oncology Center of Excellence, 1616 Eastlake Avenue, Suite 500, Seattle, WA 98102, USA
| | - Alan J Korman
- Bristol-Myers Squibb, Biologics Discovery California, Redwood City, CA 94063, USA
| | - Pia Kvistborg
- Netherlands Cancer Institute, 1066CX Amsterdam, Netherlands
| | - Cornelis Melief
- ISA Pharmaceuticals & Leiden University Medical Center, 2333 ZA Leiden, Netherlands
| | | | - A Karolina Palucka
- The Jackson Laboratory for Genomic Medicine, Farmington, CT 06032, USA. Baylor Institute for Immunology Research, Dallas, TX 75204, USA
| | | | - Harlan Robins
- Adaptive Biotechnologies, Fred Hutchinson Cancer Research Center, Seattle, WA 98102, USA
| | - Federica Sallusto
- Institute for Research in Biomedicine, Università della Svizzera italiana, 6500 Bellinzona, Switzerland
| | | | - Stephen Schoenberger
- Center for Personalized Cancer Immunotherapy, La Jolla Institute for Allergy and Immunology & UCSD Moores Cancer Center, La Jolla, San Diego, CA 92037, USA
| | - Jeffrey Sosman
- Vanderbilt University Medical Center and Vanderbilt Ingram Cancer Center, Nashville, TN 37232, USA
| | - Özlem Türeci
- CI3 Cluster for Individualized Immunotherapy, Kupferbergterasse 17-19, 55131 Mainz, Germany
| | - Benoît Van den Eynde
- Ludwig Institute for Cancer Research, Brussels branch, Brussels, BRU 1200, Belgium. Université Catholique de Louvain, Avenue Hippocrate 10, 1200 Woluwe-Saint-Lambert, Belgium. University of Oxford, Nuffield Department of Medicine, Ludwig Institute for Cancer Research, Old Road Campus Research Building, Oxford OX3 7DQ, UK
| | - Wayne Koff
- International AIDS Vaccines Initiative, 125 Broad Street, 9th Floor, New York, NY 10004, USA
| | - George Coukos
- Ludwig Cancer Research at University of Lausanne, 1066 Epalinges, Switzerland.
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57
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Kroger CJ, Spidale NA, Wang B, Tisch R. Thymic Dendritic Cell Subsets Display Distinct Efficiencies and Mechanisms of Intercellular MHC Transfer. THE JOURNAL OF IMMUNOLOGY 2016; 198:249-256. [PMID: 27895179 DOI: 10.4049/jimmunol.1601516] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Accepted: 10/28/2016] [Indexed: 11/19/2022]
Abstract
Thymic dendritic cells (DC) delete self-antigen-specific thymocytes, and drive development of Foxp3-expressing immunoregulatory T cells. Unlike medullary thymic epithelial cells, which express and present peripheral self-antigen, DC must acquire self-antigen to mediate thymic negative selection. One such mechanism entails the transfer of surface MHC-self peptide complexes from medullary thymic epithelial cells to thymic DC. Despite the importance of thymic DC cross-dressing in negative selection, the factors that regulate the process and the capacity of different thymic DC subsets to acquire MHC and stimulate thymocytes are poorly understood. In this study intercellular MHC transfer by thymic DC subsets was investigated using an MHC-mismatch-based in vitro system. Thymic conventional DC (cDC) subsets signal regulatory protein α (SIRPα+) and CD8α+ readily acquired MHC class I and II from thymic epithelial cells but plasmacytoid DC were less efficient. Intercellular MHC transfer was donor-cell specific; thymic DC readily acquired MHC from TEC plus thymic or splenic DC, whereas thymic or splenic B cells were poor donors. Furthermore DC origin influenced cross-dressing; thymic versus splenic DC exhibited an increased capacity to capture TEC-derived MHC, which correlated with direct expression of EpCAM by DC. Despite similar capacities to acquire MHC-peptide complexes, thymic CD8α+ cDC elicited increased T cell stimulation relative to SIRPα+ cDC. DC cross-dressing was cell-contact dependent and unaffected by lipid raft disruption of donor TEC. Furthermore, blocking PI3K signaling reduced MHC acquisition by thymic CD8α+ cDC and plasmacytoid DC but not SIRPα+ cDC. These findings demonstrate that multiple parameters influence the efficiency of and distinct mechanisms drive intercellular MHC transfer by thymic DC subsets.
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Affiliation(s)
- Charles J Kroger
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599; and
| | - Nicholas A Spidale
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599; and
| | - Bo Wang
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599; and
| | - Roland Tisch
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599; and .,Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
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58
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Pezzi N, Assis AF, Cotrim-Sousa LC, Lopes GS, Mosella MS, Lima DS, Bombonato-Prado KF, Passos GA. Aire knockdown in medullary thymic epithelial cells affects Aire protein, deregulates cell adhesion genes and decreases thymocyte interaction. Mol Immunol 2016; 77:157-73. [PMID: 27505711 DOI: 10.1016/j.molimm.2016.08.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Revised: 07/12/2016] [Accepted: 08/02/2016] [Indexed: 12/15/2022]
Abstract
We demonstrate that even a partial reduction of Aire mRNA levels by siRNA-induced Aire knockdown (Aire KD) has important consequences to medullary thymic epithelial cells (mTECs). Aire knockdown is sufficient to reduce Aire protein levels, impair its nuclear location, and cause an imbalance in large-scale gene expression, including genes that encode cell adhesion molecules. These genes drew our attention because adhesion molecules are implicated in the process of mTEC-thymocyte adhesion, which is critical for T cell development and the establishment of central self-tolerance. Accordingly, we consider the following: 1) mTECs contribute to the elimination of self-reactive thymocytes through adhesion; 2) Adhesion molecules play a crucial role during physical contact between these cells; and 3) Aire is an important transcriptional regulator in mTECs. However, its role in controlling mTEC-thymocyte adhesion remains unclear. Because Aire controls adhesion molecule genes, we hypothesized that the disruption of its expression could influence mTEC-thymocyte interaction. To test this hypothesis, we used a murine Aire(+) mTEC cell line as a model system to reproduce mTEC-thymocyte adhesion in vitro. Transcriptome analysis of the mTEC cell line revealed that Aire KD led to the down-modulation of more than 800 genes, including those encoding for proteins involved in cell adhesion, i.e., the extracellular matrix constituent Lama1, the CAM family adhesion molecules Vcam1 and Icam4, and those that encode peripheral tissue antigens. Thymocytes co-cultured with Aire KD mTECs had a significantly reduced capacity to adhere to these cells. This finding is the first direct evidence that Aire also plays a role in controlling mTEC-thymocyte adhesion.
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Affiliation(s)
- Nicole Pezzi
- Molecular Immunogenetics Group, Department of Genetics, Ribeirão Preto Medical School, University of São Paulo (USP), Ribeirão Preto, SP, Brazil
| | - Amanda Freire Assis
- Molecular Immunogenetics Group, Department of Genetics, Ribeirão Preto Medical School, University of São Paulo (USP), Ribeirão Preto, SP, Brazil
| | - Larissa Cotrim Cotrim-Sousa
- Molecular Immunogenetics Group, Department of Genetics, Ribeirão Preto Medical School, University of São Paulo (USP), Ribeirão Preto, SP, Brazil
| | - Gabriel Sarti Lopes
- Department of Cellular and Molecular Biology, Ribeirão Preto Medical School, USP, Ribeirão Preto, SP, Brazil
| | - Maritza Salas Mosella
- Molecular Immunogenetics Group, Department of Genetics, Ribeirão Preto Medical School, University of São Paulo (USP), Ribeirão Preto, SP, Brazil
| | - Djalma Sousa Lima
- Department of Cellular and Molecular Biology, Ribeirão Preto Medical School, USP, Ribeirão Preto, SP, Brazil
| | - Karina F Bombonato-Prado
- Department of Morphology, Physiology and Basic Pathology, School of Dentistry of Ribeirão Preto, USP, Ribeirão Preto, SP, Brazil
| | - Geraldo Aleixo Passos
- Molecular Immunogenetics Group, Department of Genetics, Ribeirão Preto Medical School, University of São Paulo (USP), Ribeirão Preto, SP, Brazil; Department of Morphology, Physiology and Basic Pathology, School of Dentistry of Ribeirão Preto, USP, Ribeirão Preto, SP, Brazil.
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59
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Lucca LE, Axisa PP, Aloulou M, Perals C, Ramadan A, Rufas P, Kyewski B, Derbinski J, Fazilleau N, Mars LT, Liblau RS. Myelin oligodendrocyte glycoprotein induces incomplete tolerance of CD4(+) T cells specific for both a myelin and a neuronal self-antigen in mice. Eur J Immunol 2016; 46:2247-59. [PMID: 27334749 DOI: 10.1002/eji.201646416] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Revised: 05/09/2016] [Accepted: 06/17/2016] [Indexed: 01/28/2023]
Abstract
T-cell polyspecificity, predicting that individual T cells recognize a continuum of related ligands, implies that multiple antigens can tolerize T cells specific for a given self-antigen. We previously showed in C57BL/6 mice that part of the CD4(+) T-cell repertoire specific for myelin oligodendrocyte glycoprotein (MOG) 35-55 also recognizes the neuronal antigen neurofilament medium (NF-M) 15-35. Such bi-specific CD4(+) T cells are frequent and produce inflammatory cytokines after stimulation. Since T cells recognizing two self-antigens would be expected to be tolerized more efficiently, this finding prompted us to study how polyspecificity impacts tolerance. We found that similar to MOG, NF-M is expressed in the thymus by medullary thymic epithelial cells, a tolerogenic population. Nevertheless, the frequency, phenotype, and capacity to transfer experimental autoimmune encephalomyelitis (EAE) of MOG35-55 -reactive CD4(+) T cells were increased in MOG-deficient but not in NF-M-deficient mice. We found that presentation of NF-M15-35 by I-A(b) on dendritic cells is of short duration, suggesting unstable MHC class II binding. Consistently, introducing an MHC-anchoring residue into NF-M15-35 (NF-M15-35 T20Y) increased its immunogenicity, activating a repertoire able to induce EAE. Our results show that in C57BL/6 mice bi-specific encephalitogenic T cells manage to escape tolerization due to inefficient exposure to two self-antigens.
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Affiliation(s)
- Liliana E Lucca
- INSERM, U1043, Toulouse, France.,Centre National de la Recherche Scientifique, U5282, Toulouse, France.,Centre de Physiopathologie Toulouse-Purpan, Université Toulouse 3, Toulouse, France
| | - Pierre-Paul Axisa
- INSERM, U1043, Toulouse, France.,Centre National de la Recherche Scientifique, U5282, Toulouse, France.,Centre de Physiopathologie Toulouse-Purpan, Université Toulouse 3, Toulouse, France
| | - Meryem Aloulou
- INSERM, U1043, Toulouse, France.,Centre National de la Recherche Scientifique, U5282, Toulouse, France.,Centre de Physiopathologie Toulouse-Purpan, Université Toulouse 3, Toulouse, France
| | - Corine Perals
- INSERM, U1043, Toulouse, France.,Centre National de la Recherche Scientifique, U5282, Toulouse, France.,Centre de Physiopathologie Toulouse-Purpan, Université Toulouse 3, Toulouse, France
| | - Abdulraouf Ramadan
- INSERM, U1043, Toulouse, France.,Centre National de la Recherche Scientifique, U5282, Toulouse, France.,Centre de Physiopathologie Toulouse-Purpan, Université Toulouse 3, Toulouse, France
| | - Pierre Rufas
- INSERM, U1043, Toulouse, France.,Centre National de la Recherche Scientifique, U5282, Toulouse, France.,Centre de Physiopathologie Toulouse-Purpan, Université Toulouse 3, Toulouse, France
| | - Bruno Kyewski
- Developmental Immunobiology, Tumor Immunology Program, German Cancer Research Center, Heidelberg, Germany
| | - Jens Derbinski
- Developmental Immunobiology, Tumor Immunology Program, German Cancer Research Center, Heidelberg, Germany
| | - Nicolas Fazilleau
- INSERM, U1043, Toulouse, France.,Centre National de la Recherche Scientifique, U5282, Toulouse, France.,Centre de Physiopathologie Toulouse-Purpan, Université Toulouse 3, Toulouse, France
| | - Lennart T Mars
- INSERM, U1043, Toulouse, France.,Centre National de la Recherche Scientifique, U5282, Toulouse, France.,Centre de Physiopathologie Toulouse-Purpan, Université Toulouse 3, Toulouse, France
| | - Roland S Liblau
- INSERM, U1043, Toulouse, France. .,Centre National de la Recherche Scientifique, U5282, Toulouse, France. .,Centre de Physiopathologie Toulouse-Purpan, Université Toulouse 3, Toulouse, France. .,CHU Toulouse, Département d'Immunologie, Toulouse, France.
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60
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Engelmann R, Biemelt A, Cordshagen A, Johl A, Kuthning D, Müller-Hilke B. The Prerequisites for Central Tolerance Induction against Citrullinated Proteins in the Mouse. PLoS One 2016; 11:e0158773. [PMID: 27362943 PMCID: PMC4928850 DOI: 10.1371/journal.pone.0158773] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Accepted: 06/21/2016] [Indexed: 12/31/2022] Open
Abstract
Objectives To assess the prerequisites for negative selection of peptidylcitrulline-specific T cells in the thymus. In detail, we here analyzed murine medullary thymic epithelial cells for the expression of peptidylarginine deiminases (PAD) and subsequent citrullination. Methods Medullary thymic epithelial cells were sorted, their mRNA was isolated and the expression of Pad genes was analyzed by quantitative PCR. Citrullination was detected by Western Blot in lysates of sorted medullary thymic epithelial cells and histologically by immunofluorescence of thymic thin sections. Results Pad2 and Pad4 are the main Pad isoforms expressed in mature medullary thymic epithelial cells of the mouse and their levels of expression are comparable to that of insulin (Ins2), another highly and promiscuously expressed protein in the thymus. Citrullination was detected in medullary thymic epithelial cells as shown by Western Blot and immunofluorescence. Conclusions Even though we here show that the murine thymus harbors the prerequisites for central tolerance to PAD and citrullinated peptides, it remains an open question whether the emergence of peptidylcitrulline-specific T cells and of autoantibodies recognizing citrullinated epitopes is caused by a failure of central or peripheral tolerance mechanisms.
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Affiliation(s)
- Robby Engelmann
- Institute of Immunology, Rostock University Medical Center, Schillingallee 70, 18057 Rostock, Germany
- * E-mail:
| | - Andra Biemelt
- Institute of Immunology, Rostock University Medical Center, Schillingallee 70, 18057 Rostock, Germany
| | - Antje Cordshagen
- Institute of Immunology, Rostock University Medical Center, Schillingallee 70, 18057 Rostock, Germany
| | - Anja Johl
- Institute of Immunology, Rostock University Medical Center, Schillingallee 70, 18057 Rostock, Germany
| | - Daniela Kuthning
- Institute of Immunology, Rostock University Medical Center, Schillingallee 70, 18057 Rostock, Germany
| | - Brigitte Müller-Hilke
- Institute of Immunology, Rostock University Medical Center, Schillingallee 70, 18057 Rostock, Germany
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61
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Abstract
More than 15 years ago, mutations in the autoimmune regulator (AIRE) gene were identified as the cause of autoimmune polyglandular syndrome type 1 (APS1). It is now clear that this transcription factor has a crucial role in promoting self-tolerance in the thymus by regulating the expression of a wide array of self-antigens that have the commonality of being tissue-restricted in their expression pattern in the periphery. In this Review, we highlight many of the recent advances in our understanding of the complex biology that is related to AIRE, with a particular focus on advances in genetics, molecular interactions and the effect of AIRE on thymic selection of regulatory T cells. Furthermore, we highlight new areas of biology that are potentially affected by this key regulator of immune tolerance.
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Affiliation(s)
- Maureen A. Su
- Department of Pediatrics, School of Medicine, and Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599
- Department of Microbiology/Immunology, School of Medicine, and Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599
| | - Mark S. Anderson
- Diabetes Center, University of California, San Francisco, San Francisco, CA 94143
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Lin J, Yang L, Silva HM, Trzeciak A, Choi Y, Schwab SR, Dustin ML, Lafaille JJ. Increased generation of Foxp3(+) regulatory T cells by manipulating antigen presentation in the thymus. Nat Commun 2016; 7:10562. [PMID: 26923114 PMCID: PMC4773449 DOI: 10.1038/ncomms10562] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2015] [Accepted: 12/28/2015] [Indexed: 12/22/2022] Open
Abstract
Regulatory T-cell (Treg) selection in the thymus is essential to prevent autoimmune diseases. Although important rules for Treg selection have been established, there is controversy regarding the degree of self-reactivity displayed by T-cell receptors expressed by Treg cells. In this study we have developed a model of autoimmune skin inflammation, to determine key parameters in the generation of skin-reactive Treg cells in the thymus (tTreg). tTreg development is predominantly AIRE dependent, with an AIRE-independent component. Without the knowledge of antigen recognized by skin-reactive Treg cells, we are able to enhance skin-specific tTreg cell generation using three approaches. First, we increase medullary thymic epithelial cells by using mice lacking osteoprotegerin or by adding TRANCE (RANKL, Tnfsf11). Second, we inject intrathymically peripheral dendritic cells from skin-draining sites. Finally, we inject skin tissue lysates intrathymically. These findings have implications for enhancing the generation of organ-specific Treg cells in autoimmune diseases.
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Affiliation(s)
- Jiqiang Lin
- Molecular Pathogenesis Program, Kimmel Center for Biology and Medicine at the Skirball Institute, New York University School of Medicine, 540 First Avenue, New York, New York 10016, USA
- The Sackler Institute of Graduate Biomedical Sciences, New York University School of Medicine, New York, New York 10016, USA
| | - Lu Yang
- Molecular Pathogenesis Program, Kimmel Center for Biology and Medicine at the Skirball Institute, New York University School of Medicine, 540 First Avenue, New York, New York 10016, USA
- The Sackler Institute of Graduate Biomedical Sciences, New York University School of Medicine, New York, New York 10016, USA
| | - Hernandez Moura Silva
- Molecular Pathogenesis Program, Kimmel Center for Biology and Medicine at the Skirball Institute, New York University School of Medicine, 540 First Avenue, New York, New York 10016, USA
| | - Alissa Trzeciak
- Molecular Pathogenesis Program, Kimmel Center for Biology and Medicine at the Skirball Institute, New York University School of Medicine, 540 First Avenue, New York, New York 10016, USA
| | - Yongwon Choi
- Department of Pathology and Laboratory Medicine, Institute for Immunology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104, USA
| | - Susan R. Schwab
- Molecular Pathogenesis Program, Kimmel Center for Biology and Medicine at the Skirball Institute, New York University School of Medicine, 540 First Avenue, New York, New York 10016, USA
- Department of Pathology, New York University School of Medicine, New York, New York 10016, USA
| | - Michael L. Dustin
- Molecular Pathogenesis Program, Kimmel Center for Biology and Medicine at the Skirball Institute, New York University School of Medicine, 540 First Avenue, New York, New York 10016, USA
- Department of Pathology, New York University School of Medicine, New York, New York 10016, USA
- Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, Kennedy Institute of Rheumatology, University of Oxford, Oxford OX3 7FY, UK
| | - Juan J. Lafaille
- Molecular Pathogenesis Program, Kimmel Center for Biology and Medicine at the Skirball Institute, New York University School of Medicine, 540 First Avenue, New York, New York 10016, USA
- Department of Pathology, New York University School of Medicine, New York, New York 10016, USA
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63
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Evolutionary conserved gene co-expression drives generation of self-antigen diversity in medullary thymic epithelial cells. J Autoimmun 2016; 67:65-75. [DOI: 10.1016/j.jaut.2015.10.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Revised: 09/23/2015] [Accepted: 10/05/2015] [Indexed: 01/01/2023]
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64
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De Martino L, Capalbo D, Improda N, Lorello P, Ungaro C, Di Mase R, Cirillo E, Pignata C, Salerno M. Novel Findings into AIRE Genetics and Functioning: Clinical Implications. Front Pediatr 2016; 4:86. [PMID: 27597936 PMCID: PMC4992815 DOI: 10.3389/fped.2016.00086] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Accepted: 08/02/2016] [Indexed: 01/22/2023] Open
Abstract
Autoimmune polyendocrinopathy candidiasis ectodermal dystrophy (APECED), formerly known as autoimmune polyendocrine syndrome type 1, is a paradigm of a monogenic autoimmune disease caused by mutations of a gene, named autoimmune regulator (AIRE). AIRE acts as a transcription regulator that promotes immunological central tolerance by inducing the ectopic thymic expression of many tissue-specific antigens. Although the syndrome is a monogenic disease, it is characterized by a wide variability of the clinical expression with no significant correlation between genotype and phenotype. Indeed, many aspects regarding the exact role of AIRE and APECED pathogenesis still remain unraveled. In the last decades, several studies in APECED and in its mouse experimental counterpart have revealed new insights on how immune system learns self-tolerance. Moreover, novel interesting findings have extended our understanding of AIRE's function and regulation thus improving our knowledge on the pathogenesis of APECED. In this review, we will summarize recent novelties on molecular mechanisms underlying the development of APECED and their clinical implications.
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Affiliation(s)
- Lucia De Martino
- Pediatric Section, Department of Translational Medical Sciences, Federico II University , Naples , Italy
| | | | - Nicola Improda
- Pediatric Section, Department of Translational Medical Sciences, Federico II University , Naples , Italy
| | - Paola Lorello
- Pediatric Section, Department of Translational Medical Sciences, Federico II University , Naples , Italy
| | - Carla Ungaro
- Department of Pediatrics, Federico II University , Naples , Italy
| | | | - Emilia Cirillo
- Pediatric Section, Department of Translational Medical Sciences, Federico II University , Naples , Italy
| | - Claudio Pignata
- Pediatric Section, Department of Translational Medical Sciences, Federico II University , Naples , Italy
| | - Mariacarolina Salerno
- Pediatric Section, Department of Translational Medical Sciences, Federico II University , Naples , Italy
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65
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Di Zenzo G, Amber KT, Sayar BS, Müller EJ, Borradori L. Immune response in pemphigus and beyond: progresses and emerging concepts. Semin Immunopathol 2015; 38:57-74. [DOI: 10.1007/s00281-015-0541-1] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Accepted: 10/30/2015] [Indexed: 12/18/2022]
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66
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Anderson G, Jenkinson WE. Co-ordination of intrathymic self-representation. Nat Immunol 2015; 16:895-6. [PMID: 26287586 DOI: 10.1038/ni.3251] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Graham Anderson
- MRC Centre for Immune Regulation, Institute for Biomedical Research, Medical School, University of Birmingham, Birmingham, UK
| | - William E Jenkinson
- MRC Centre for Immune Regulation, Institute for Biomedical Research, Medical School, University of Birmingham, Birmingham, UK
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67
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Adult Thymic Medullary Epithelium Is Maintained and Regenerated by Lineage-Restricted Cells Rather Than Bipotent Progenitors. Cell Rep 2015; 13:1432-1443. [PMID: 26549457 DOI: 10.1016/j.celrep.2015.10.012] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Revised: 08/24/2015] [Accepted: 10/02/2015] [Indexed: 01/09/2023] Open
Abstract
Medullary thymic epithelial cells (mTECs) play an essential role in establishing self-tolerance in T cells. mTECs originate from bipotent TEC progenitors that generate both mTECs and cortical TECs (cTECs), although mTEC-restricted progenitors also have been reported. Here, we report in vivo fate-mapping analysis of cells that transcribe β5t, a cTEC trait expressed in bipotent progenitors, during a given period in mice. We show that, in adult mice, most mTECs are derived from progenitors that transcribe β5t during embryogenesis and the neonatal period up to 1 week of age. The contribution of adult β5t(+) progenitors was minor even during injury-triggered regeneration. Our results further demonstrate that adult mTEC-restricted progenitors are derived from perinatal β5t(+) progenitors. These results indicate that the adult thymic medullary epithelium is maintained and regenerated by mTEC-lineage cells that pass beyond the bipotent stage during early ontogeny.
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68
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Meredith M, Zemmour D, Mathis D, Benoist C. Aire controls gene expression in the thymic epithelium with ordered stochasticity. Nat Immunol 2015; 16:942-9. [PMID: 26237550 PMCID: PMC4632529 DOI: 10.1038/ni.3247] [Citation(s) in RCA: 133] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Accepted: 07/09/2015] [Indexed: 12/13/2022]
Abstract
The transcription factor Aire controls immunological tolerance by inducing the ectopic thymic expression of many tissue-specific genes, acting broadly by removing stops on the transcriptional machinery. To better understand Aire's specificity, we performed single-cell RNA-seq and DNA-methylation analysis of Aire-sufficient and Aire-deficient medullary epithelial cells (mTECs). Each of Aire's target genes was induced in only a minority of mTECs, independently of DNA-methylation patterns, as small inter-chromosomal gene clusters activated in concert in a proportion of mTECs. These microclusters differed between individual mice. Thus, our results suggest an organization of the DNA or of the epigenome that results from stochastic determinism but is 'bookmarked' and stable through mTEC divisions, which ensures more effective presentation of self antigens and favors diversity of self-tolerance between individuals.
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Affiliation(s)
- Matthew Meredith
- Division of Immunology, Department of Microbiology and Immunobiology, Harvard Medical School, and Evergrande Center for Immunologic Diseases, Harvard Medical School and Brigham and Women’s Hospital, Boston MA 02115, USA
| | - David Zemmour
- Division of Immunology, Department of Microbiology and Immunobiology, Harvard Medical School, and Evergrande Center for Immunologic Diseases, Harvard Medical School and Brigham and Women’s Hospital, Boston MA 02115, USA
| | - Diane Mathis
- Division of Immunology, Department of Microbiology and Immunobiology, Harvard Medical School, and Evergrande Center for Immunologic Diseases, Harvard Medical School and Brigham and Women’s Hospital, Boston MA 02115, USA
| | - Christophe Benoist
- Division of Immunology, Department of Microbiology and Immunobiology, Harvard Medical School, and Evergrande Center for Immunologic Diseases, Harvard Medical School and Brigham and Women’s Hospital, Boston MA 02115, USA
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69
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Brennecke P, Reyes A, Pinto S, Rattay K, Nguyen M, Küchler R, Huber W, Kyewski B, Steinmetz LM. Single-cell transcriptome analysis reveals coordinated ectopic gene-expression patterns in medullary thymic epithelial cells. Nat Immunol 2015; 16:933-41. [PMID: 26237553 PMCID: PMC4675844 DOI: 10.1038/ni.3246] [Citation(s) in RCA: 103] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Accepted: 07/08/2015] [Indexed: 12/30/2022]
Abstract
Expression of tissue-restricted self antigens (TRAs) in medullary thymic epithelial cells (mTECs) is essential for the induction of self-tolerance and prevents autoimmunity, with each TRA being expressed in only a few mTECs. How this process is regulated in single mTECs and is coordinated at the population level, such that the varied single-cell patterns add up to faithfully represent TRAs, is poorly understood. Here we used single-cell RNA sequencing and obtained evidence of numerous recurring TRA-co-expression patterns, each present in only a subset of mTECs. Co-expressed genes clustered in the genome and showed enhanced chromatin accessibility. Our findings characterize TRA expression in mTECs as a coordinated process that might involve local remodeling of chromatin and thus ensures a comprehensive representation of the immunological self.
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Affiliation(s)
- Philip Brennecke
- 1] Department of Genetics, Stanford University, School of Medicine, California, USA. [2] Stanford Genome Technology Center, Stanford University, California, USA
| | - Alejandro Reyes
- European Molecular Biology Laboratory, Genome Biology Unit, Heidelberg, Germany
| | - Sheena Pinto
- Division of Developmental Immunology, German Cancer Research Center, Heidelberg, Germany
| | - Kristin Rattay
- Division of Developmental Immunology, German Cancer Research Center, Heidelberg, Germany
| | - Michelle Nguyen
- 1] Department of Genetics, Stanford University, School of Medicine, California, USA. [2] Stanford Genome Technology Center, Stanford University, California, USA
| | - Rita Küchler
- Division of Developmental Immunology, German Cancer Research Center, Heidelberg, Germany
| | - Wolfgang Huber
- European Molecular Biology Laboratory, Genome Biology Unit, Heidelberg, Germany
| | - Bruno Kyewski
- Division of Developmental Immunology, German Cancer Research Center, Heidelberg, Germany
| | - Lars M Steinmetz
- 1] Department of Genetics, Stanford University, School of Medicine, California, USA. [2] Stanford Genome Technology Center, Stanford University, California, USA. [3] European Molecular Biology Laboratory, Genome Biology Unit, Heidelberg, Germany
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70
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Hu Z, Lancaster JN, Ehrlich LIR. The Contribution of Chemokines and Migration to the Induction of Central Tolerance in the Thymus. Front Immunol 2015; 6:398. [PMID: 26300884 PMCID: PMC4528182 DOI: 10.3389/fimmu.2015.00398] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Accepted: 07/20/2015] [Indexed: 02/01/2023] Open
Abstract
As T cells develop, they migrate throughout the thymus where they undergo essential bi-directional signaling with stromal cells in distinct thymic microenvironments. Immature thymocyte progenitors are located in the thymic cortex. Following T cell receptor expression and positive selection, thymocytes undergo a dramatic transition: they become rapidly motile and relocate to the thymic medulla. Antigen-presenting cells (APCs) within the cortex and medulla display peptides derived from a wide array of self-proteins, which promote thymocyte self-tolerance. If a thymocyte is auto-reactive against such antigens, it undergoes either negative selection, via apoptosis, or differentiation into the regulatory T cell lineage. This induction of central tolerance is critical for prevention of autoimmunity. Chemokines and adhesion molecules play an essential role in tolerance induction, as they promote migration of developing thymocytes through the different thymic microenvironments and enhance interactions with APCs displaying self-antigens. Herein, we review the contribution of chemokines and other regulators of thymocyte localization and motility to T cell development, with a focus on their contribution to the induction of central tolerance.
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Affiliation(s)
- Zicheng Hu
- Ehrlich Laboratory, Department of Molecular Biosciences, Institute for Cellular and Molecular Biology, The University of Texas at Austin , Austin, TX , USA
| | - Jessica Naomi Lancaster
- Ehrlich Laboratory, Department of Molecular Biosciences, Institute for Cellular and Molecular Biology, The University of Texas at Austin , Austin, TX , USA
| | - Lauren I R Ehrlich
- Ehrlich Laboratory, Department of Molecular Biosciences, Institute for Cellular and Molecular Biology, The University of Texas at Austin , Austin, TX , USA
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71
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Skogberg G, Telemo E, Ekwall O. Exosomes in the Thymus: Antigen Transfer and Vesicles. Front Immunol 2015; 6:366. [PMID: 26257734 PMCID: PMC4507453 DOI: 10.3389/fimmu.2015.00366] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Accepted: 07/06/2015] [Indexed: 12/31/2022] Open
Abstract
Thymocytes go through several steps of maturation and selection in the thymus in order to form a functional pool of effector T-cells and regulatory T-cells in the periphery. Close interactions between thymocytes, thymic epithelial cells, and dendritic cells are of vital importance for the maturation, selection, and lineage decision of the thymocytes. One important question that is still unanswered is how a relatively small epithelial cell population can present a vast array of self-antigens to the manifold larger population of developing thymocytes in this selection process. Here, we review and discuss the literature concerning antigen transfer from epithelial cells with a focus on exosomes. Exosomes are nano-sized vesicles released from a cell into the extracellular space. These vesicles can carry proteins, microRNAs, and mRNAs between cells and are thus able to participate in intercellular communication. Exosomes have been shown to be produced by thymic epithelial cells and to carry tissue-restricted antigens and MHC molecules, which may enable them to participate in the thymocyte selection process.
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Affiliation(s)
- Gabriel Skogberg
- Department of Rheumatology and Inflammation Research, Institute of Medicine, The Sahlgrenska Academy, Gothenburg University , Gothenburg , Sweden
| | - Esbjörn Telemo
- Department of Rheumatology and Inflammation Research, Institute of Medicine, The Sahlgrenska Academy, Gothenburg University , Gothenburg , Sweden
| | - Olov Ekwall
- Department of Rheumatology and Inflammation Research, Institute of Medicine, The Sahlgrenska Academy, Gothenburg University , Gothenburg , Sweden ; Department of Pediatrics, Institute of Clinical Sciences, The Sahlgrenska Academy, Gothenburg University , Gothenburg , Sweden
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72
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St-Pierre C, Trofimov A, Brochu S, Lemieux S, Perreault C. Differential Features of AIRE-Induced and AIRE-Independent Promiscuous Gene Expression in Thymic Epithelial Cells. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2015; 195:498-506. [PMID: 26034170 DOI: 10.4049/jimmunol.1500558] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Accepted: 05/04/2015] [Indexed: 12/16/2023]
Abstract
Establishment of self-tolerance in the thymus depends on promiscuous expression of tissue-restricted Ags (TRA) by thymic epithelial cells (TEC). This promiscuous gene expression (pGE) is regulated in part by the autoimmune regulator (AIRE). To evaluate the commonalities and discrepancies between AIRE-dependent and -independent pGE, we analyzed the transcriptome of the three main TEC subsets in wild-type and Aire knockout mice. We found that the impact of AIRE-dependent pGE is not limited to generation of TRA. AIRE decreases, via non-cell autonomous mechanisms, the expression of genes coding for positive regulators of cell proliferation, and it thereby reduces the number of cortical TEC. In mature medullary TEC, AIRE-driven pGE upregulates non-TRA coding genes that enhance cell-cell interactions (e.g., claudins, integrins, and selectins) and are probably of prime relevance to tolerance induction. We also found that AIRE-dependent and -independent TRA present several distinctive features. In particular, relative to AIRE-induced TRA, AIRE-independent TRA are more numerous and show greater splicing complexity. Furthermore, we report that AIRE-dependent versus -independent TRA project nonredundant representations of peripheral tissues in the thymus.
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Affiliation(s)
- Charles St-Pierre
- Institute for Research in Immunology and Cancer, University of Montreal, Montreal, Quebec H3C 3J7, Canada; Department of Medicine, University of Montreal, Montreal, Quebec H3C 3J7, Canada; and
| | - Assya Trofimov
- Institute for Research in Immunology and Cancer, University of Montreal, Montreal, Quebec H3C 3J7, Canada; Department of Medicine, University of Montreal, Montreal, Quebec H3C 3J7, Canada; and Department of Computer Science and Operations Research, University of Montreal, Montreal, Quebec H3C 3J7, Canada
| | - Sylvie Brochu
- Institute for Research in Immunology and Cancer, University of Montreal, Montreal, Quebec H3C 3J7, Canada; Department of Medicine, University of Montreal, Montreal, Quebec H3C 3J7, Canada; and
| | - Sébastien Lemieux
- Institute for Research in Immunology and Cancer, University of Montreal, Montreal, Quebec H3C 3J7, Canada; Department of Computer Science and Operations Research, University of Montreal, Montreal, Quebec H3C 3J7, Canada
| | - Claude Perreault
- Institute for Research in Immunology and Cancer, University of Montreal, Montreal, Quebec H3C 3J7, Canada; Department of Medicine, University of Montreal, Montreal, Quebec H3C 3J7, Canada; and
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73
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Human thymic epithelial primary cells produce exosomes carrying tissue-restricted antigens. Immunol Cell Biol 2015; 93:727-34. [PMID: 25776846 PMCID: PMC4575951 DOI: 10.1038/icb.2015.33] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Revised: 01/23/2015] [Accepted: 02/17/2015] [Indexed: 12/14/2022]
Abstract
Exosomes are nano-sized vesicles released by cells into the extracellular space and have been shown to be present in thymic tissue both in mice and in humans. The source of thymic exosomes is however still an enigma and hence it is not known whether thymic epithelial cells (TECs) are able to produce exosomes. In this work, we have cultured human TECs and isolated exosomes. These exosomes carry tissue-restricted antigens (TRAs), for example, myelin basic protein and desmoglein 3. The presence of TRAs indicates a possible role for thymic epithelium-derived exosomes in the selection process of thymocytes. The key contribution of these exosomes could be to disseminate self-antigens from the thymic epithelia, thus making them more accessible to the pool of maturing thymocytes. This would increase the coverage of TRAs within the thymus, and facilitate the process of positive and negative selection.
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74
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Ucar O, Rattay K. Promiscuous Gene Expression in the Thymus: A Matter of Epigenetics, miRNA, and More? Front Immunol 2015; 6:93. [PMID: 25784915 PMCID: PMC4347492 DOI: 10.3389/fimmu.2015.00093] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Accepted: 02/17/2015] [Indexed: 12/17/2022] Open
Abstract
The induction of central tolerance in the course of T cell development crucially depends on promiscuous gene expression (pGE) in medullary thymic epithelial cells (mTECs). mTECs express a genome-wide variety of tissue-restricted antigens (TRAs), preventing the escape of autoreactive T cells to the periphery, and the development of severe autoimmunity. Most of our knowledge of how pGE is controlled comes from studies on the autoimmune regulator (Aire). Aire activates the expression of a large subset of TRAs by interacting with the general transcriptional machinery and promoting transcript elongation. However, further factors regulating Aire-independent TRAs must be at play. Recent studies demonstrated that pGE in general and the function of Aire in particular are controlled by epigenetic and post-transcriptional mechanisms. This mini-review summarizes current knowledge of the regulation of pGE by miRNA and epigenetic regulatory mechanisms such as DNA methylation, histone modifications, and chromosomal topology.
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Affiliation(s)
- Olga Ucar
- Division of Developmental Immunology, German Cancer Research Center , Heidelberg , Germany
| | - Kristin Rattay
- Division of Developmental Immunology, German Cancer Research Center , Heidelberg , Germany
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75
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Rattay K, Claude J, Rezavandy E, Matt S, Hofmann TG, Kyewski B, Derbinski J. Homeodomain-interacting protein kinase 2, a novel autoimmune regulator interaction partner, modulates promiscuous gene expression in medullary thymic epithelial cells. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2015; 194:921-8. [PMID: 25552543 DOI: 10.4049/jimmunol.1402694] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Promiscuous expression of a plethora of tissue-restricted Ags (TRAs) by medullary thymic epithelial cells (mTECs) plays an essential role in T cell tolerance. Although the cellular mechanisms by which promiscuous gene expression (pGE) imposes T cell tolerance have been well characterized, the underlying molecular mechanisms remain poorly understood. The autoimmune regulator (AIRE) is to date the only validated molecule known to regulate pGE. AIRE is part of higher-order multiprotein complexes, which promote transcription, elongation, and splicing of a wide range of target genes. How AIRE and its partners mediate these various effects at the molecular level is still largely unclear. Using a yeast two-hybrid screen, we searched for novel AIRE-interacting proteins and identified the homeodomain-interacting protein kinase 2 (HIPK2) as a novel partner. HIPK2 partially colocalized with AIRE in nuclear bodies upon cotransfection and in human mTECs in situ. Moreover, HIPK2 phosphorylated AIRE in vitro and suppressed the coactivator activity of AIRE in a kinase-dependent manner. To evaluate the role of Hipk2 in modulating the function of AIRE in vivo, we compared whole-genome gene signatures of purified mTEC subsets from TEC-specific Hipk2 knockout mice with control mice and identified a small set of differentially expressed genes. Unexpectedly, most differentially expressed genes were confined to the CD80(lo) mTEC subset and preferentially included AIRE-independent TRAs. Thus, although it modulates gene expression in mTECs and in addition affects the size of the medullary compartment, TEC-specific HIPK2 deletion only mildly affects AIRE-directed pGE in vivo.
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Affiliation(s)
- Kristin Rattay
- Division of Developmental Immunobiology, Tumor Immunology Program, German Cancer Research Center, 69120 Heidelberg, Germany; and
| | - Janine Claude
- Division of Developmental Immunobiology, Tumor Immunology Program, German Cancer Research Center, 69120 Heidelberg, Germany; and
| | - Esmail Rezavandy
- Division of Developmental Immunobiology, Tumor Immunology Program, German Cancer Research Center, 69120 Heidelberg, Germany; and
| | - Sonja Matt
- Zelluläre Seneszenz-Gruppe, Deutsches Krebsforschungszentrum-Zentrum für Molekulare Biologie Allianz, Deutsches Krebsforschungszentrum, 69120 Heidelberg, Germany
| | - Thomas G Hofmann
- Zelluläre Seneszenz-Gruppe, Deutsches Krebsforschungszentrum-Zentrum für Molekulare Biologie Allianz, Deutsches Krebsforschungszentrum, 69120 Heidelberg, Germany
| | - Bruno Kyewski
- Division of Developmental Immunobiology, Tumor Immunology Program, German Cancer Research Center, 69120 Heidelberg, Germany; and
| | - Jens Derbinski
- Division of Developmental Immunobiology, Tumor Immunology Program, German Cancer Research Center, 69120 Heidelberg, Germany; and
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76
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Sansom SN, Shikama-Dorn N, Zhanybekova S, Nusspaumer G, Macaulay IC, Deadman ME, Heger A, Ponting CP, Holländer GA. Population and single-cell genomics reveal the Aire dependency, relief from Polycomb silencing, and distribution of self-antigen expression in thymic epithelia. Genome Res 2014; 24:1918-31. [PMID: 25224068 PMCID: PMC4248310 DOI: 10.1101/gr.171645.113] [Citation(s) in RCA: 229] [Impact Index Per Article: 22.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2013] [Accepted: 09/12/2014] [Indexed: 12/18/2022]
Abstract
Promiscuous gene expression (PGE) by thymic epithelial cells (TEC) is essential for generating a diverse T cell antigen receptor repertoire tolerant to self-antigens, and thus for avoiding autoimmunity. Nevertheless, the extent and nature of this unusual expression program within TEC populations and single cells are unknown. Using deep transcriptome sequencing of carefully identified mouse TEC subpopulations, we discovered a program of PGE that is common between medullary (m) and cortical TEC, further elaborated in mTEC, and completed in mature mTEC expressing the autoimmune regulator gene (Aire). TEC populations are capable of expressing up to 19,293 protein-coding genes, the highest number of genes known to be expressed in any cell type. Remarkably, in mouse mTEC, Aire expression alone positively regulates 3980 tissue-restricted genes. Notably, the tissue specificities of these genes include known targets of autoimmunity in human AIRE deficiency. Led by the observation that genes induced by Aire expression are generally characterized by a repressive chromatin state in somatic tissues, we found these genes to be strongly associated with H3K27me3 marks in mTEC. Our findings are consistent with AIRE targeting and inducing the promiscuous expression of genes previously epigenetically silenced by Polycomb group proteins. Comparison of the transcriptomes of 174 single mTEC indicates that genes induced by Aire expression are transcribed stochastically at low cell frequency. Furthermore, when present, Aire expression-dependent transcript levels were 16-fold higher, on average, in individual TEC than in the mTEC population.
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Affiliation(s)
- Stephen N Sansom
- MRC Computational Genomics Analysis and Training Programme, MRC Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, OX1 3PT, United Kingdom;
| | - Noriko Shikama-Dorn
- Paediatric Immunology, Department of Biomedicine, University of Basel, and The Basel University Children's Hospital, Basel, 4058, Switzerland
| | - Saule Zhanybekova
- Paediatric Immunology, Department of Biomedicine, University of Basel, and The Basel University Children's Hospital, Basel, 4058, Switzerland
| | - Gretel Nusspaumer
- Paediatric Immunology, Department of Biomedicine, University of Basel, and The Basel University Children's Hospital, Basel, 4058, Switzerland
| | - Iain C Macaulay
- Wellcome Trust Sanger Institute-EBI Single Cell Genomics Centre, Wellcome Trust Sanger Institute, Hinxton, Cambridge, CB10 1SA, United Kingdom
| | - Mary E Deadman
- Developmental Immunology, Department of Paediatrics, and the Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, United Kingdom
| | - Andreas Heger
- MRC Computational Genomics Analysis and Training Programme, MRC Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, OX1 3PT, United Kingdom
| | - Chris P Ponting
- MRC Computational Genomics Analysis and Training Programme, MRC Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, OX1 3PT, United Kingdom; Wellcome Trust Sanger Institute-EBI Single Cell Genomics Centre, Wellcome Trust Sanger Institute, Hinxton, Cambridge, CB10 1SA, United Kingdom
| | - Georg A Holländer
- Paediatric Immunology, Department of Biomedicine, University of Basel, and The Basel University Children's Hospital, Basel, 4058, Switzerland; Developmental Immunology, Department of Paediatrics, and the Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, United Kingdom
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77
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Warren BD, Kinsey WK, McGinnis LK, Christenson LK, Jasti S, Stevens AM, Petroff BK, Petroff MG. Ovarian autoimmune disease: clinical concepts and animal models. Cell Mol Immunol 2014; 11:510-21. [PMID: 25327908 PMCID: PMC4220844 DOI: 10.1038/cmi.2014.97] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Revised: 09/11/2014] [Accepted: 09/11/2014] [Indexed: 01/08/2023] Open
Abstract
The ovary is not an immunologically privileged organ, but a breakdown in tolerogenic mechanisms for ovary-specific antigens has disastrous consequences on fertility in women, and this is replicated in murine models of autoimmune disease. Isolated ovarian autoimmune disease is rare in women, likely due to the severity of the disease and the inability to transmit genetic information conferring the ovarian disease across generations. Nonetheless, autoimmune oophoritis is often observed in association with other autoimmune diseases, particularly autoimmune adrenal disease, and takes a toll on both society and individual health. Studies in mice have revealed at least two mechanisms that protect the ovary from autoimmune attack. These mechanisms include control of autoreactive T cells by thymus-derived regulatory T cells, as well as a role for the autoimmune regulator (AIRE), a transcriptional regulator that induces expression of tissue-restricted antigens in medullary thymic epithelial cells during development of T cells. Although the latter mechanism is incompletely defined, it is well established that failure of either results in autoimmune-mediated targeting and depletion of ovarian follicles. In this review, we will address the clinical features and consequences of autoimmune-mediated ovarian infertility in women, as well as the possible mechanisms of disease as revealed by animal models.
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Affiliation(s)
- Bryce D Warren
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, KS, USA
| | - William K Kinsey
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, KS, USA
| | - Lynda K McGinnis
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, KS, USA
| | - Lane K Christenson
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, KS, USA
| | - Susmita Jasti
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, KS, USA
| | - Anne M Stevens
- Research Center for Immunity and Immunotherapies, Children's Hospital and Regional Medical Center, and Division of Rheumatology, Department of Pediatrics, University of Washington, Seattle, WA, USA
| | - Brian K Petroff
- 1] Department of Internal Medicine, University of Kansas Medical Center, Kansas City, KS, USA [2] Present address: Department of Pathobiology and Diagnostic Investigation, Michigan State University College of Veterinary Medicine, East Lansing, MI, USA
| | - Margaret G Petroff
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, KS, USA
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78
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Global transcriptional profiling reveals distinct functions of thymic stromal subsets and age-related changes during thymic involution. Cell Rep 2014; 9:402-415. [PMID: 25284794 DOI: 10.1016/j.celrep.2014.08.070] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Revised: 08/06/2014] [Accepted: 08/27/2014] [Indexed: 11/24/2022] Open
Abstract
Age-associated thymic involution results in diminished T cell output and function in aged individuals. However, molecular mediators contributing to the decline in thymic function during early thymic involution remain largely unknown. Here, we present transcriptional profiling of purified thymic stromal subsets from mice 1, 3, and 6 months of age spanning early thymic involution. The data implicate unanticipated biological functions for a subset of thymic epithelial cells. The predominant transcriptional signature of early thymic involution is decreased expression of cell-cycle-associated genes and E2F3 transcriptional targets in thymic epithelial subsets. Also, expression of proinflammatory genes increases with age in thymic dendritic cells. Many genes previously implicated in late involution are already deregulated by 3-6 months of age. We provide these thymic stromal data sets, along with thymocyte data sets, in a readily searchable web-based platform, as a resource for investigations into thymocyte:stromal interactions and mechanisms of thymic involution.
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79
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Abstract
Self-tolerance imposition requires the presentation of self-antigens by a variety of thymic antigen-presenting cells. In this issue of Immunity, Perry et al. (2014) reveal unidirectional self-antigen transfer from medullary thymic epithelial cells to dendritic cells as an essential aspect.
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Affiliation(s)
- Bruno Kyewski
- Division of Developmental Immunology, German Cancer Research Center, 69120 Heidelberg, Germany.
| | - Markus Feuerer
- Helmholtz Young Investigator Group Immune Tolerance, Tumor Immunology Program, German Cancer Research Center, 69120 Heidelberg, Germany
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80
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Abstract
A critical function of the thymus is to help enforce tolerance to self. The importance of central tolerance in preventing autoimmunity has been enlightened by a deeper understanding of the interactions of developing T cells with a diverse population of thymic antigen presenting cell populations. Furthermore, there has been rapid progress in our understanding of how autoreactive T cell specificities are diverted into the T regulatory lineage. Here we review and highlight the recent progress in how tolerance is imposed on the developing thymocyte repertoire.
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Affiliation(s)
- Maria L Mouchess
- Diabetes Center, University of California-San Francisco, Box 0540, San Francisco, CA, 94143, USA
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81
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Klein L, Kyewski B, Allen PM, Hogquist KA. Positive and negative selection of the T cell repertoire: what thymocytes see (and don't see). Nat Rev Immunol 2014; 14:377-91. [PMID: 24830344 PMCID: PMC4757912 DOI: 10.1038/nri3667] [Citation(s) in RCA: 882] [Impact Index Per Article: 88.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The fate of developing T cells is specified by the interaction of their antigen receptors with self-peptide-MHC complexes that are displayed by thymic antigen-presenting cells (APCs). Various subsets of thymic APCs are strategically positioned in particular thymic microenvironments and they coordinate the selection of a functional and self-tolerant T cell repertoire. In this Review, we discuss the different strategies that these APCs use to sample and process self antigens and to thereby generate partly unique, 'idiosyncratic' peptide-MHC ligandomes. We discuss how the particular composition of the peptide-MHC ligandomes that are presented by specific APC subsets not only shapes the T cell repertoire in the thymus but may also indelibly imprint the behaviour of mature T cells in the periphery.
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Affiliation(s)
- Ludger Klein
- Institute for Immunology, Ludwig Maximilians University, 80336 Munich, Germany
| | - Bruno Kyewski
- Division of Developmental Immunology, German Cancer Research Center, 69120 Heidelberg, Germany
| | - Paul M Allen
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri 63110, USA
| | - Kristin A Hogquist
- Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, Minnesota 55414, USA
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82
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Waterfield M, Khan IS, Cortez JT, Fan U, Metzger T, Greer A, Fasano K, Martinez-Llordella M, Pollack JL, Erle DJ, Su M, Anderson MS. The transcriptional regulator Aire coopts the repressive ATF7ip-MBD1 complex for the induction of immunotolerance. Nat Immunol 2014; 15:258-65. [PMID: 24464130 PMCID: PMC4172453 DOI: 10.1038/ni.2820] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Accepted: 12/18/2013] [Indexed: 12/13/2022]
Abstract
The maintenance of immunological tolerance requires the deletion of self-reactive T cells in the thymus. The expression of genes encoding tissue-specific antigens (TSAs) by thymic epithelial cells is critical for this process and depends on activity of the transcriptional regulator Aire; however, the molecular mechanisms Aire uses to target loci encoding TSAs are unknown. Here we identified two Aire-interacting proteins known to be involved in gene repression, ATF7ip and MBD1, that were required for Aire's targeting of loci encoding TSAs. Moreover, Mbd1(-/-) mice developed pathological autoimmunity and had a defect in Aire-dependent thymic expression of genes encoding TSAs, which underscores the importance of Aire's interaction with the ATF7ip-MBD1 protein complex in maintaining central tolerance.
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Affiliation(s)
- Michael Waterfield
- Diabetes Center, University of California San Francisco, 513 Parnassus Avenue, San Francisco, CA 94143
- Department of Pediatrics, University of California San Francisco, 533 Parnassus Avenue, San Francisco, CA 94143
| | - Imran S. Khan
- Diabetes Center, University of California San Francisco, 513 Parnassus Avenue, San Francisco, CA 94143
| | - Jessica T. Cortez
- Diabetes Center, University of California San Francisco, 513 Parnassus Avenue, San Francisco, CA 94143
| | - Una Fan
- Diabetes Center, University of California San Francisco, 513 Parnassus Avenue, San Francisco, CA 94143
| | - Todd Metzger
- Diabetes Center, University of California San Francisco, 513 Parnassus Avenue, San Francisco, CA 94143
| | - Alexandra Greer
- Department of Microbiology & Immunology, University of California San Francisco, 513 Parnassus Avenue, San Francisco, CA 94143
| | - Kayla Fasano
- Diabetes Center, University of California San Francisco, 513 Parnassus Avenue, San Francisco, CA 94143
| | - Marc Martinez-Llordella
- Department Liver Sciences, Division of Transplantation Immunology & Mucosal Biology, King’s College London, Institute of Liver Studies, 3rd Floor Cheyne Wing, Denmark Hill, SE5 9RS
| | - Joshua L. Pollack
- Department of Medicine, University of California San Francisco, 15504 Street, San Francisco, CA 94158
| | - David J. Erle
- Department of Medicine, University of California San Francisco, 15504 Street, San Francisco, CA 94158
| | - Maureen Su
- Department of Pediatrics, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Mark S. Anderson
- Diabetes Center, University of California San Francisco, 513 Parnassus Avenue, San Francisco, CA 94143
- Department of Medicine, University of California San Francisco, 15504 Street, San Francisco, CA 94158
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83
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Perniola R, Musco G. The biophysical and biochemical properties of the autoimmune regulator (AIRE) protein. BIOCHIMICA ET BIOPHYSICA ACTA 2014; 1842:326-37. [PMID: 24275490 DOI: 10.1016/j.bbadis.2013.11.020] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2013] [Revised: 11/11/2013] [Accepted: 11/18/2013] [Indexed: 01/20/2023]
Abstract
AIRE (for autoimmune regulator) is a multidomain protein that performs a fundamental function in the thymus and possibly in the secondary lymphoid organs: the regulation, especially in the sense of activation, of the process of gene transcription in cell lines deputed to the presentation of self-antigens to the maturing T lymphocytes. The apoptosis of the elements bearing T-cell receptors with critical affinity for the exhibited self-antigens prevents the escape of autoreactive clones and represents a simple and efficient mechanism of deletional self-tolerance. However, AIRE action relies on an articulated complex of biophysical and biochemical properties, in most cases attributable to single subspecialized domains. Here a thorough review of the matter is presented, with a privileged look at the pathogenic changes of AIRE that interfere with such properties and lead to the impairment in its chief function.
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Affiliation(s)
- Roberto Perniola
- Department of Pediatrics - Neonatal Intensive Care, V. Fazzi Regional Hospital, Piazza F. Muratore, I-73100, Lecce, Italy.
| | - Giovanna Musco
- Biomolecular NMR Laboratory, Center of Translational Genomics and Bioinformatics, Dulbecco Telethon Institute at San Raffaele Scientific Institute, Via Olgettina 58, I-20132, Milan, Italy.
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84
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Rouhani SJ, Eccles JD, Tewalt EF, Engelhard VH. Regulation of T-cell Tolerance by Lymphatic Endothelial Cells. ACTA ACUST UNITED AC 2014; 5. [PMID: 25580369 PMCID: PMC4286360 DOI: 10.4172/2155-9899.1000242] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Lymphatic endothelial cells are most often thought of as structural cells that form the lymphatic vasculature, which transports fluid out of peripheral tissues and transports antigens and antigen presenting cells to lymph nodes. Recently, it has been shown that lymphatic endothelial cells also dynamically respond to and influence the immune response in several ways. Here, we describe how lymphatic endothelial cells induce peripheral T-cell tolerance and how this relates to tolerance induced by other types of antigen presenting cells. Furthermore, the ability of lymphatic endothelial cells to alter immune responses under steady-state or inflammatory conditions is explored, and the therapeutic potential of bypassing lymphatic endothelial cell-induced tolerance to enhance cancer immunotherapy is discussed.
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Affiliation(s)
- Sherin J Rouhani
- Carter Immunology Center and Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Jacob D Eccles
- Carter Immunology Center and Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Eric F Tewalt
- Carter Immunology Center and Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Victor H Engelhard
- Carter Immunology Center and Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
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85
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Amber KT, Staropoli P, Shiman MI, Elgart GW, Hertl M. Autoreactive T cells in the immune pathogenesis of pemphigus vulgaris. Exp Dermatol 2013; 22:699-704. [DOI: 10.1111/exd.12229] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/20/2013] [Indexed: 12/18/2022]
Affiliation(s)
- Kyle T. Amber
- Department of Dermatology and Cutaneous Surgery; University of Miami Miller School of Medicine; Miami FL USA
| | - Patrick Staropoli
- Department of Dermatology and Cutaneous Surgery; University of Miami Miller School of Medicine; Miami FL USA
| | - Michael I. Shiman
- Department of Dermatology and Cutaneous Surgery; University of Miami Miller School of Medicine; Miami FL USA
| | - George W. Elgart
- Department of Dermatology and Cutaneous Surgery; University of Miami Miller School of Medicine; Miami FL USA
| | - Michael Hertl
- Department of Dermatology and Allergology; Philipps-Universität; Marburg Germany
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86
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Metzger TC, Khan IS, Gardner JM, Mouchess ML, Johannes KP, Krawisz AK, Skrzypczynska KM, Anderson MS. Lineage tracing and cell ablation identify a post-Aire-expressing thymic epithelial cell population. Cell Rep 2013; 5:166-79. [PMID: 24095736 PMCID: PMC3820422 DOI: 10.1016/j.celrep.2013.08.038] [Citation(s) in RCA: 93] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Revised: 07/25/2013] [Accepted: 08/22/2013] [Indexed: 11/20/2022] Open
Abstract
Thymic epithelial cells in the medulla (mTECs) play a critical role in enforcing central tolerance through expression and presentation of tissue-specific antigens (TSAs) and deletion of autoreactive thymocytes. TSA expression requires autoimmune regulator (Aire), a transcriptional activator present in a subset of mTECs characterized by high CD80 and major histocompatibility complex II expression and a lack of potential for differentiation or proliferation. Here, using an Aire-DTR transgenic line, we show that short-term ablation specifically targets Aire(+) mTECs, which quickly undergo RANK-dependent recovery. Repeated ablation also affects Aire(-) mTECs, and using an inducible Aire-Cre fate-mapping system, we find that this results from the loss of a subset of mTECs that showed prior expression of Aire, maintains intermediate TSA expression, and preferentially migrates toward the center of the medulla. These results clearly identify a distinct stage of mTEC development and underscore the diversity of mTECs that play a key role in maintaining tolerance.
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Affiliation(s)
- Todd C Metzger
- Diabetes Center, University of California, San Francisco, San Francisco, CA 94143-0540, USA
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87
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Overlapping gene coexpression patterns in human medullary thymic epithelial cells generate self-antigen diversity. Proc Natl Acad Sci U S A 2013; 110:E3497-505. [PMID: 23980163 DOI: 10.1073/pnas.1308311110] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Promiscuous expression of numerous tissue-restricted self-antigens (TRAs) in medullary thymic epithelial cells (mTECs) is essential to safeguard self-tolerance. A distinct feature of promiscuous gene expression is its mosaic pattern (i.e., at a given time, each self-antigen is expressed only in 1-3% of mTECs). How this mosaic pattern is generated at the single-cell level is currently not understood. Here, we show that subsets of human mTECs expressing a particular TRA coexpress distinct sets of genes. We identified three coexpression groups comprising overlapping and complementary gene sets, which preferentially mapped to certain chromosomes and intrachromosomal gene clusters. Coexpressed gene loci tended to colocalize to the same nuclear subdomain. The TRA subsets aligned along progressive differentiation stages within the mature mTEC subset and, in vitro, interconverted along this sequence. Our data suggest that single mTECs shift through distinct gene pools, thus scanning a sizeable fraction of the overall repertoire of promiscuously expressed self-antigens. These findings have implications for the temporal and spatial (re)presentation of self-antigens in the medulla in the context of tolerance induction.
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88
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Akiyama T, Shinzawa M, Qin J, Akiyama N. Regulations of gene expression in medullary thymic epithelial cells required for preventing the onset of autoimmune diseases. Front Immunol 2013; 4:249. [PMID: 23986760 PMCID: PMC3752772 DOI: 10.3389/fimmu.2013.00249] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Accepted: 08/09/2013] [Indexed: 11/13/2022] Open
Abstract
Elimination of potential self-reactive T cells in the thymus is crucial for preventing the onset of autoimmune diseases. Epithelial cell subsets localized in thymic medulla [medullary thymic epithelial cells (mTECs)] contribute to this process by supplying a wide range of self-antigens that are otherwise expressed in a tissue-specific manner (TSAs). Expression of some TSAs in mTECs is controlled by the autoimmune regulator (AIRE) protein, of which dysfunctional mutations are the causative factor of autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED). In addition to the elimination of self-reactive T cells, recent studies indicated roles of mTECs in the development of Foxp3-positive regulatory T cells, which suppress autoimmunity and excess immune reactions in peripheral tissues. The TNF family cytokines, RANK ligand, CD40 ligand, and lymphotoxin were found to promote the differentiation of AIRE- and TSA-expressing mTECs. Furthermore, activation of NF-κB is essential for mTEC differentiation. In this mini-review, we focus on molecular mechanisms that regulate induction of AIRE and TSA expression and discuss possible contributions of these mechanisms to prevent the onset of autoimmune diseases.
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Affiliation(s)
- Taishin Akiyama
- Division of Cellular and Molecular Biology, Institute of Medical Science, University of Tokyo , Tokyo , Japan
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89
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Matsumoto M, Nishikawa Y, Nishijima H, Morimoto J, Matsumoto M, Mouri Y. Which model better fits the role of aire in the establishment of self-tolerance: the transcription model or the maturation model? Front Immunol 2013; 4:210. [PMID: 23885257 PMCID: PMC3717480 DOI: 10.3389/fimmu.2013.00210] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Accepted: 07/09/2013] [Indexed: 11/13/2022] Open
Abstract
The discovery of Aire-dependent transcriptional control of many tissue-restricted self-antigen (TRA) genes in thymic epithelial cells in the medulla (medullary thymic epithelial cells, mTECs) has raised the intriguing question of how the single Aire gene can influence the transcription of such a large number of TRA genes within mTECs. From a mechanistic viewpoint, there are two possible models to explain the function of Aire in this action. In the first model, TRAs are considered to be the direct target genes of Aire’s transcriptional activity. In this scenario, the lack of Aire protein within cells would result in the defective TRA gene expression, while the maturation program of mTECs would be unaffected in principle. The second model hypothesizes that Aire is necessary for the maturation program of mTECs. In this case, we assume that the mTEC compartment does not mature normally in the absence of Aire. If acquisition of the properties of TRA gene expression depends on the maturation status of mTECs, a defect of such an Aire-dependent maturation program in Aire-deficient mTECs can also result in impaired TRA gene expression. In this brief review, we will focus on these two contrasting models for the roles of Aire in controlling the expression of TRAs within mTECs.
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Affiliation(s)
- Mitsuru Matsumoto
- Division of Molecular Immunology, Institute for Enzyme Research, University of Tokushima , Tokushima , Japan
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90
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Bonito AJ, Aloman C, Fiel MI, Danzl NM, Cha S, Weinstein EG, Jeong S, Choi Y, Walsh MC, Alexandropoulos K. Medullary thymic epithelial cell depletion leads to autoimmune hepatitis. J Clin Invest 2013; 123:3510-24. [PMID: 23867620 DOI: 10.1172/jci65414] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2012] [Accepted: 05/17/2013] [Indexed: 12/23/2022] Open
Abstract
TRAF6, an E3 ubiquitin protein ligase, plays a critical role in T cell tolerance by regulating medullary thymic epithelial cell (mTEC) development. mTECs regulate T cell tolerance by ectopically expressing self-antigens and eliminating autoreactive T cells in the thymus. Here we show that mice with mTEC depletion due to conditional deletion of Traf6 expression in murine thymic epithelial cells (Traf6ΔTEC mice) showed a surprisingly narrow spectrum of autoimmunity affecting the liver. The liver inflammation in Traf6ΔTEC mice exhibited all the histological and immunological characteristics of human autoimmune hepatitis (AIH). The role of T cells in AIH establishment was supported by intrahepatic T cell population changes and AIH development after transfer of liver T cells into immunodeficient mice. Despite a 50% reduction in natural Treg thymic output, peripheral tolerance in Traf6ΔTEC mice was normal, whereas compensatory T regulatory mechanisms were evident in the liver of these animals. These data indicate that mTECs exert a cell-autonomous role in central T cell tolerance and organ-specific autoimmunity, but play a redundant role in peripheral tolerance. These findings also demonstrate that Traf6ΔTEC mice are a relevant model with which to study the pathophysiology of AIH, as well as autoantigen-specific T cell responses and regulatory mechanisms underlying this disease.
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Affiliation(s)
- Anthony J Bonito
- Department of Medicine/Clinical Immunology, Icahn School of Medicine at Mount Sinai, New York, New York 10029, USA
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91
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Romano R, Palamaro L, Fusco A, Giardino G, Gallo V, Del Vecchio L, Pignata C. FOXN1: A Master Regulator Gene of Thymic Epithelial Development Program. Front Immunol 2013; 4:187. [PMID: 23874334 PMCID: PMC3709140 DOI: 10.3389/fimmu.2013.00187] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Accepted: 06/25/2013] [Indexed: 11/18/2022] Open
Abstract
T cell ontogeny is a sophisticated process, which takes place within the thymus through a series of well-defined discrete stages. The process requires a proper lympho-stromal interaction. In particular, cortical and medullary thymic epithelial cells (cTECs, mTECs) drive T cell differentiation, education, and selection processes, while the thymocyte-dependent signals allow thymic epithelial cells (TECs) to maturate and provide an appropriate thymic microenvironment. Alterations in genes implicated in thymus organogenesis, including Tbx1, Pax1, Pax3, Pax9, Hoxa3, Eya1, and Six1, affect this well-orchestrated process, leading to disruption of thymic architecture. Of note, in both human and mice, the primordial TECs are yet unable to fully support T cell development and only after the transcriptional activation of the Forkhead-box n1 (FOXN1) gene in the thymic epithelium this essential function is acquired. FOXN1 is a master regulator in the TEC lineage specification in that it down-stream promotes transcription of genes, which, in turn, regulate TECs differentiation. In particular, FOXN1 mainly regulates TEC patterning in the fetal stage and TEC homeostasis in the post-natal thymus. An inborn null mutation in FOXN1 leads to Nude/severe combined immunodeficiency (SCID) phenotype in mouse, rat, and humans. In Foxn1−/− nude animals, initial formation of the primordial organ is arrested and the primordium is not colonized by hematopoietic precursors, causing a severe primary T cell immunodeficiency. In humans, the Nude/SCID phenotype is characterized by congenital alopecia of the scalp, eyebrows, and eyelashes, nail dystrophy, and a severe T cell immunodeficiency, inherited as an autosomal recessive disorder. Aim of this review is to summarize all the scientific information so far available to better characterize the pivotal role of the master regulator FOXN1 transcription factor in the TEC lineage specifications and functionality.
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Affiliation(s)
- Rosa Romano
- Department of Translational Medical Sciences, "Federico II" University , Naples , Italy
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92
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Abstract
Exosomes are nanosized membrane-bound vesicles that are released by various cell types and are capable of carrying proteins, lipids and RNAs which can be delivered to recipient cells. Exosomes play a role in intercellular communication and have been described to mediate immunologic information. In this article we report the first isolation and characterization of exosomes from human thymic tissue. Using electron microscopy, particle size determination, density gradient measurement, flow cytometry, proteomic analysis and microRNA profiling we describe the morphology, size, density, protein composition and microRNA content of human thymic exosomes. The thymic exosomes share characteristics with previously described exosomes such as antigen presentation molecules, but they also exhibit thymus specific features regarding surface markers, protein content and microRNA profile. Interestingly, thymic exosomes carry proteins that have a tissue restricted expression in the periphery which may suggest a role in T cell selection and the induction of central tolerance. We speculate that thymic exosomes may provide the means for intercellular information exchange necessary for negative selection and regulatory T cell formation of the developing thymocytes within the human thymic medulla.
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93
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Abstract
T cells orchestrate pathogen-specific adaptive immune responses by identifying peptides derived from pathogenic proteins that are displayed on the surface of infected cells. Host cells also display peptide fragments from the host's own proteins. Incorrectly identifying peptides derived from the body's own proteome as pathogenic can result in autoimmune disease. To minimize autoreactivity, immature T cells that respond to self-peptides are deleted in the thymus by a process called negative selection. However, negative selection is imperfect, and autoreactive T cells exist in healthy individuals. To understand how autoimmunity is yet avoided, without loss of responsiveness to pathogens, we have developed a model of T-cell training and response. Our model shows that T cells reliably respond to infection and avoid autoimmunity because collective decisions made by the T-cell population, rather than the responses of individual T cells, determine biological outcomes. The theory is qualitatively consistent with experimental data and yields a criterion for thymic selection to be adequate for suppressing autoimmunity.
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94
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Ohigashi I, Zuklys S, Sakata M, Mayer CE, Zhanybekova S, Murata S, Tanaka K, Holländer GA, Takahama Y. Aire-expressing thymic medullary epithelial cells originate from β5t-expressing progenitor cells. Proc Natl Acad Sci U S A 2013; 110:9885-90. [PMID: 23720310 PMCID: PMC3683726 DOI: 10.1073/pnas.1301799110] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The thymus provides multiple microenvironments that are essential for the development and repertoire selection of T lymphocytes. The thymic cortex induces the generation and positive selection of T lymphocytes, whereas the thymic medulla establishes self-tolerance among the positively selected T lymphocytes. Cortical thymic epithelial cells (cTECs) and medullary TECs (mTECs) constitute the major stromal cells that structurally form and functionally characterize the cortex and the medulla, respectively. cTECs and mTECs are both derived from the endodermal epithelium of the third pharyngeal pouch. However, the molecular and cellular characteristics of the progenitor cells for the distinct TEC lineages are unclear. Here we report the preparation and characterization of mice that express the recombinase Cre instead of β5t, a proteasome subunit that is abundant in cTECs and not detected in other cell types, including mTECs. By crossing β5t-Cre knock-in mice with loxP-dependent GFP reporter mice, we found that β5t-Cre-mediated recombination occurs specifically in TECs but not in any other cell types in the mouse. Surprisingly, in addition to cTECs, β5t-Cre-loxP-mediated GFP expression was detected in almost all mTECs. These results indicate that the majority of mTECs, including autoimmune regulator-expressing mTECs, are derived from β5t-expressing progenitor cells.
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Affiliation(s)
- Izumi Ohigashi
- Division of Experimental Immunology, Institute for Genome Research, University of Tokushima, Tokushima 770-8503, Japan
| | - Saulius Zuklys
- Laboratory of Pediatric Immunology, Department of Biomedicine, University of Basel and University Children's Hospital Basel, 4058 Basel, Switzerland
| | - Mie Sakata
- Division of Experimental Immunology, Institute for Genome Research, University of Tokushima, Tokushima 770-8503, Japan
| | - Carlos E. Mayer
- Laboratory of Pediatric Immunology, Department of Biomedicine, University of Basel and University Children's Hospital Basel, 4058 Basel, Switzerland
| | - Saule Zhanybekova
- Laboratory of Pediatric Immunology, Department of Biomedicine, University of Basel and University Children's Hospital Basel, 4058 Basel, Switzerland
| | - Shigeo Murata
- Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo 113-0033, Japan
| | - Keiji Tanaka
- Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan; and
| | - Georg A. Holländer
- Laboratory of Pediatric Immunology, Department of Biomedicine, University of Basel and University Children's Hospital Basel, 4058 Basel, Switzerland
- Department of Paediatrics and the Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DU, United Kingdom
| | - Yousuke Takahama
- Division of Experimental Immunology, Institute for Genome Research, University of Tokushima, Tokushima 770-8503, Japan
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95
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Dzhagalov IL, Chen KG, Herzmark P, Robey EA. Elimination of self-reactive T cells in the thymus: a timeline for negative selection. PLoS Biol 2013; 11:e1001566. [PMID: 23700386 PMCID: PMC3660248 DOI: 10.1371/journal.pbio.1001566] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2012] [Accepted: 04/11/2013] [Indexed: 01/22/2023] Open
Abstract
Two-photon microscopy and flow cytometry reveal the timing of thymocyte death and the surprisingly close coupling between cell death and phagocytosis during negative selection in thymic slices. The elimination of autoreactive T cells occurs via thymocyte apoptosis and removal by thymic phagocytes, but the sequence of events in vivo, and the relationship between thymocyte death and phagocytic clearance, are unknown. Here we address these questions by following a synchronized cohort of thymocytes undergoing negative selection within a three-dimensional thymic tissue environment, from the initial encounter with a negative selecting ligand to thymocyte death and clearance. Encounter with cognate peptide–MHC complexes results in rapid calcium flux and migratory arrest in auto-reactive thymocytes over a broad range of peptide concentrations, followed by a lag period in which gene expression changes occurred, but there was little sign of thymocyte death. Caspase 3 activation and thymocyte loss were first detectable at 2 and 3 hours, respectively, and entry of individual thymocytes into the death program occurred asynchronously over the next 10 hours. Two-photon time-lapse imaging revealed that thymocyte death and phagocytosis occurred simultaneously, often with thymocytes engulfed prior to changes in chromatin and membrane permeability. Our data provide a timeline for negative selection and reveal close coupling between cell death and clearance in the thymus. As an important safeguard against autoimmunity, T cells bearing autoreactive T cell antigen receptors are eliminated during their development in the thymus, a process known as negative selection. Although much is known about the molecular events involved in negative selection, surprisingly little is known about the dynamic aspects of the process. Here we examine a synchronized population of developing T cells (thymocytes) undergoing negative selection within three-dimensional living thymic tissue. We show that the initial encounter with negative selecting ligands results in migratory arrest, but in spite of this synchronous early response, individual thymocytes then undergo delayed and asynchronous entry into the death program between 2 and 12 hours thereafter. Using time-lapse two-photon imaging, we reveal that thymocyte death and the clearance of the dead cells invariably occur together, with many thymocytes already engulfed by a macrophage before the cell death-related changes in chromatin and membrane permeability are evident. These data provide a timeline of the major events during negative selection, and suggest close coupling between thymocyte death and clearance by macrophages.
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Affiliation(s)
- Ivan Lilyanov Dzhagalov
- Division of Immunology and Pathogenesis, Department of Molecular and Cell Biology, University of California, Berkeley, California, United States of America
| | - Katherine Grace Chen
- Division of Immunology and Pathogenesis, Department of Molecular and Cell Biology, University of California, Berkeley, California, United States of America
| | - Paul Herzmark
- Division of Immunology and Pathogenesis, Department of Molecular and Cell Biology, University of California, Berkeley, California, United States of America
| | - Ellen A. Robey
- Division of Immunology and Pathogenesis, Department of Molecular and Cell Biology, University of California, Berkeley, California, United States of America
- * E-mail:
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96
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Lkhagvasuren E, Sakata M, Ohigashi I, Takahama Y. Lymphotoxin β receptor regulates the development of CCL21-expressing subset of postnatal medullary thymic epithelial cells. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2013; 190:5110-7. [PMID: 23585674 DOI: 10.4049/jimmunol.1203203] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Medullary thymic epithelial cells (mTECs) play a pivotal role in the establishment of self-tolerance in T cells by ectopically expressing various tissue-restricted self-Ags and by chemoattracting developing thymocytes. The nuclear protein Aire expressed by mTECs contributes to the promiscuous expression of self-Ags, whereas CCR7-ligand (CCR7L) chemokines expressed by mTECs are responsible for the attraction of positively selected thymocytes. It is known that lymphotoxin signals from the positively selected thymocytes preferentially promote the expression of CCR7L rather than Aire in postnatal mTECs. However, it is unknown how lymphotoxin signals differentially regulate the expression of CCR7L and Aire in mTECs and whether CCR7L-expressing mTECs and Aire-expressing mTECs are distinct populations. In this study, we show that the majority of postnatal mTECs that express CCL21, a CCR7L chemokine, represent an mTEC subpopulation distinct from the Aire-expressing mTEC subpopulation. Interestingly, the development of CCL21-expressing mTECs, but not Aire-expressing mTECs, is impaired in mice deficient in the lymphotoxin β receptor. These results indicate that postnatal mTECs consist of heterogeneous subsets that differ in the expression of CCL21 and Aire, and that lymphotoxin β receptor regulates the development of the CCL21-expressing subset rather than the Aire-expressing subset of postnatal mTECs.
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Affiliation(s)
- Enkhsaikhan Lkhagvasuren
- Division of Experimental Immunology, Institute for Genome Research, University of Tokushima, Tokushima 770-8503, Japan
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97
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Sun L, Luo H, Li H, Zhao Y. Thymic epithelial cell development and differentiation: cellular and molecular regulation. Protein Cell 2013; 4:342-55. [PMID: 23589020 DOI: 10.1007/s13238-013-3014-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2013] [Accepted: 03/11/2013] [Indexed: 11/26/2022] Open
Abstract
Thymic epithelial cells (TECs) are one of the most important components in thymic microenvironment supporting thymocyte development and maturation. TECs, composed of cortical and medullary TECs, are derived from a common bipotent progenitor, mediating thymocyte positive and negative selections. Multiple levels of signals including intracellular signaling networks and cell-cell interaction are required for TEC development and differentiation. Transcription factors Foxn1 and autoimmune regulator (Aire) are powerful regulators promoting TEC development and differentiation. Crosstalks with thymocytes and other stromal cells for extrinsic signals like RANKL, CD40L, lymphotoxin, fibroblast growth factor (FGF) and Wnt are also definitely required to establish a functional thymic microenvironment. In this review, we will summarize our current understanding about TEC development and differentiation, and its underlying multiple signal pathways.
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Affiliation(s)
- Lina Sun
- State Key Laboratory of Biomembrane and Membrane Biotechnology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
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98
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Gallo V, Giardino G, Capalbo D, Palamaro L, Romano R, Santamaria F, Maio F, Salerno M, Vajro P, Pignata C. Alterations of the autoimmune regulator transcription factor and failure of central tolerance: APECED as a model. Expert Rev Clin Immunol 2013; 9:43-51. [PMID: 23256763 DOI: 10.1586/eci.12.88] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Self-nonself discrimination plays a key role in inducing a productive immunity and in preventing autoimmune reactions. Central tolerance within the thymus and peripheral tolerance in peripheral lymphoid organs lead to immunologic nonresponsiveness against self-components. The central tolerance represents the mechanism by which T cells binding with high avidity to self-antigens are eliminated through the so-called negative selection. Thymic medullary epithelial cells and medullary dendritic cells play a key role in this process, through the expression of a large number of tissue-specific self-antigens involving the transcription factor autoimmune regulator (AIRE). Mutations of AIRE result in autoimmune polyendocrinopathy candidiasis ectodermal dystrophy, a rare autosomal recessive disease (OMIM 240300), which is the paradigm of a genetically determined failure of central tolerance and autoimmunity. This review focuses on recent advances in the molecular mechanisms of central tolerance, their alterations and clinical implication.
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Affiliation(s)
- Vera Gallo
- Department of Pediatrics, Federico II University, S Pansini 5, 8013 Naples, Italy
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99
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Abstract
The development of CD4(+) helper and CD8(+) cytotoxic T-cells expressing the αβ form of the T-cell receptor (αβTCR) takes place in the thymus, a primary lymphoid organ containing distinct cortical and medullary microenvironments. While the cortex represents a site of early T-cell precursor development, and the positive selection of CD4(+)8(+) thymocytes, the thymic medulla plays a key role in tolerance induction, ensuring that thymic emigrants are purged of autoreactive αβTCR specificities. In recent years, advances have been made in understanding the development and function of thymic medullary epithelial cells, most notably the subset defined by expression of the Autoimmune Regulator (Aire) gene. Here, we summarize current knowledge of the developmental mechanisms regulating thymus medulla development, and examine the role of the thymus medulla in recessive (negative selection) and dominant (T-regulatory cell) tolerance.
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100
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Wu G, Hirabayashi K, Sato S, Akiyama N, Akiyama T, Shiota K, Yagi S. DNA methylation profile of Aire-deficient mouse medullary thymic epithelial cells. BMC Immunol 2012; 13:58. [PMID: 23116172 PMCID: PMC3546423 DOI: 10.1186/1471-2172-13-58] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2012] [Accepted: 10/27/2012] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND Medullary thymic epithelial cells (mTECs) are characterized by ectopic expression of self-antigens during the establishment of central tolerance. The autoimmune regulator (Aire), which is specifically expressed in mTECs, is responsible for the expression of a large repertoire of tissue-restricted antigens (TRAs) and plays a role in the development of mTECs. However, Aire-deficient mTECs still express TRAs. Moreover, a subset of mTECs, which are considered to be at a stage of terminal differentiation, exists in the Aire-deficient thymus. The phenotype of a specific cell type in a multicellular organism is governed by the epigenetic regulation system. DNA methylation modification is an important component of this system. Every cell or tissue type displays a DNA methylation profile, consisting of tissue-dependent and differentially methylated regions (T-DMRs), and this profile is involved in cell-type-specific genome usage. The aim of this study was to examine the DNA methylation profile of mTECs by using Aire-deficient mTECs as a model. RESULTS We identified the T-DMRs of mTECs (mTEC-T-DMRs) via genome-wide DNA methylation analysis of Aire(-/-) mTECs by comparison with the liver, brain, thymus, and embryonic stem cells. The hypomethylated mTEC-T-DMRs in Aire(-/-) mTECs were associated with mTEC-specific genes, including Aire, CD80, and Trp63, as well as other genes involved in the RANK signaling pathway. While these mTEC-T-DMRs were also hypomethylated in Aire(+/+) mTECs, they were hypermethylated in control thymic stromal cells. We compared the pattern of DNA methylation levels at a total of 55 mTEC-T-DMRs and adjacent regions and found that the DNA methylation status was similar for Aire(+/+) and Aire(-/-) mTECs but distinct from that of athymic cells and tissues. CONCLUSIONS These results indicate a unique DNA methylation profile that is independent of Aire in mTECs. This profile is distinct from other cell types in the thymic microenvironment and is indicated to be involved in the differentiation of the mTEC lineage.
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Affiliation(s)
- Guoying Wu
- Laboratory of Cellular Biochemistry, Department of Animal Resource Sciences /Veterinary Medical Science, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1, Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan
| | - Keiji Hirabayashi
- Laboratory of Cellular Biochemistry, Department of Animal Resource Sciences /Veterinary Medical Science, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1, Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan
| | - Shinya Sato
- Laboratory of Cellular Biochemistry, Department of Animal Resource Sciences /Veterinary Medical Science, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1, Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan
| | - Nobuko Akiyama
- Division of Cellular and Molecular Biology, Institute of Medical Science, The University of Tokyo, 4-6-1, Shirokane-dai, Minato-ku, Tokyo, 108-8639, Japan
| | - Taishin Akiyama
- Division of Cellular and Molecular Biology, Institute of Medical Science, The University of Tokyo, 4-6-1, Shirokane-dai, Minato-ku, Tokyo, 108-8639, Japan
| | - Kunio Shiota
- Laboratory of Cellular Biochemistry, Department of Animal Resource Sciences /Veterinary Medical Science, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1, Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan
| | - Shintaro Yagi
- Laboratory of Cellular Biochemistry, Department of Animal Resource Sciences /Veterinary Medical Science, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1, Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan
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