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Villegas JA, Gradolatto A, Truffault F, Roussin R, Berrih-Aknin S, Le Panse R, Dragin N. Cultured Human Thymic-Derived Cells Display Medullary Thymic Epithelial Cell Phenotype and Functionality. Front Immunol 2018; 9:1663. [PMID: 30083154 PMCID: PMC6064927 DOI: 10.3389/fimmu.2018.01663] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Accepted: 07/04/2018] [Indexed: 12/13/2022] Open
Abstract
Thymic epithelial cells are one of the main components of the thymic microenvironment required for T-cell development. In this work, we describe an efficient method free of enzymatic and Facs-sorted methods to culture human medullary thymic epithelial cells without affecting the cell phenotypic, physiologic and functional features. Human medulla thymic epithelial cells (mTECs) are obtained by culturing thymic biopsies explants. After 7 days of primo-culture, mTECs keep their ability to express key molecules involved in immune tolerance processes such as autoimmune regulator, tissue-specific antigens, chemokines, and cytokines. In addition, the cells sensor their cultured environment and consequently adjust their gene expression network. Therefore, we describe and provide a human mTEC model that may be used to test the effect of various molecules on thymic epithelial cell homeostasis and physiology. This method should allow the investigations of the specificities and the knowledge of human mTECs in normal or pathological conditions and therefore discontinue the extrapolations done on the murine models.
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Affiliation(s)
- José A Villegas
- INSERM, AIM, Center of Research in Myology, UMRS974, Sorbonne University, Paris, France
| | - Angeline Gradolatto
- INSERM, AIM, Center of Research in Myology, UMRS974, Sorbonne University, Paris, France
| | - Frédérique Truffault
- INSERM, AIM, Center of Research in Myology, UMRS974, Sorbonne University, Paris, France
| | | | - Sonia Berrih-Aknin
- INSERM, AIM, Center of Research in Myology, UMRS974, Sorbonne University, Paris, France
| | - Rozen Le Panse
- INSERM, AIM, Center of Research in Myology, UMRS974, Sorbonne University, Paris, France
| | - Nadine Dragin
- INSERM, AIM, Center of Research in Myology, UMRS974, Sorbonne University, Paris, France.,Inovarion, Paris, France
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2
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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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3
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Wu W, Shi Y, Xia H, Chai Q, Jin C, Ren B, Zhu M. Epithelial LTβR signaling controls the population size of the progenitors of medullary thymic epithelial cells in neonatal mice. Sci Rep 2017; 7:44481. [PMID: 28290551 PMCID: PMC5349570 DOI: 10.1038/srep44481] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 02/09/2017] [Indexed: 12/14/2022] Open
Abstract
The establishment of T cell central tolerance critically relies on the development and maintenance of the medullary thymic epithelial cells (mTECs). Disrupted signaling of lymphotoxin beta receptor (LTβR) results in dramatically reduced mTEC population. However, whether LTβR directly or indirectly control mTECs remains undetermined; how LTβR controls this process also remain unclear. In this study, by utilizing K14-Cre × Ltbrfl/fl conditional knockout (cKO) mice, we show that epithelial intrinsic LTβR was essential for the mTEC development postnatally. Mechanistically, LTβR did not directly impact the proliferation or survival of mTECs; the maturation of mTECs from MHC-IIlo to MHC-IIhi stage was also unaltered in the absence of LTβR; interestingly, the number of mTEC progenitors (Cld3,4hiSSEA-1+) was found significantly reduced in LTβR cKO mice at the neonatal stage, but not at E18.5. Consequently, epithelial deficiency of LTβR resulted in significant defect of thymic negative selection as demonstrated using OT-I and RIP-OVA transgenic mouse system. In summary, our study clarifies the epithelial intrinsic role of LTβR on mTEC development and function; more importantly, it reveals a previously unrecognized function of LTβR on the control of the size of mTEC progenitor population.
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Affiliation(s)
- Weiwei Wu
- Key Laboratory of Infection and Immunity, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yaoyao Shi
- Key Laboratory of Infection and Immunity, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Huan Xia
- Key Laboratory of Infection and Immunity, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Qian Chai
- Key Laboratory of Infection and Immunity, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
| | - Caiwei Jin
- Key Laboratory of Infection and Immunity, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Boyang Ren
- Key Laboratory of Infection and Immunity, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Mingzhao Zhu
- Key Laboratory of Infection and Immunity, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
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Oliveira EH, Macedo C, Collares CV, Freitas AC, Donate PB, Sakamoto-Hojo ET, Donadi EA, Passos GA. Aire Downregulation Is Associated with Changes in the Posttranscriptional Control of Peripheral Tissue Antigens in Medullary Thymic Epithelial Cells. Front Immunol 2016; 7:526. [PMID: 27933063 PMCID: PMC5120147 DOI: 10.3389/fimmu.2016.00526] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Accepted: 11/10/2016] [Indexed: 12/14/2022] Open
Abstract
Autoimmune regulator (Aire) is a transcriptional regulator of peripheral tissue antigens (PTAs) and microRNAs (miRNAs) in medullary thymic epithelial cells (mTECs). In this study, we tested the hypothesis that Aire also played a role as an upstream posttranscriptional controller in these cells and that variation in its expression might be associated with changes in the interactions between miRNAs and the mRNAs encoding PTAs. We demonstrated that downregulation of Aire in vivo in the thymuses of BALB/c mice imbalanced the large-scale expression of these two RNA species and consequently their interactions. The expression profiles of a large set of mTEC miRNAs and mRNAs isolated from the thymuses of mice subjected (or not) to small-interfering-induced Aire gene knockdown revealed that 87 miRNAs and 4,558 mRNAs were differentially expressed. The reconstruction of the miRNA–mRNA interaction networks demonstrated that interactions between these RNAs were under Aire influence and therefore changed when this gene was downregulated. Prior to Aire-knockdown, only members of the miR-let-7 family interacted with a set of PTA mRNAs. Under Aire-knockdown conditions, a larger set of miRNA families and their members established this type of interaction. Notably, no previously described Aire-dependent PTA interacted with the miRNAs, indicating that these PTAs were somehow refractory. The miRNA–mRNA interactions were validated by calculating the minimal free energy of the pairings between the miRNA seed regions and the mRNA 3′ UTRs and within the cellular milieu using the luciferase reporter gene assay. These results suggest the existence of a link between transcriptional and posttranscriptional control because Aire downregulation alters the miRNA–mRNA network controlling PTAs in mTEC cells.
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Affiliation(s)
- Ernna H Oliveira
- Molecular Immunogenetics Group, Department of Genetics, Ribeirão Preto Medical School, University of São Paulo (USP) , São Paulo , Brazil
| | - Claudia Macedo
- Molecular Immunogenetics Group, Department of Genetics, Ribeirão Preto Medical School, University of São Paulo (USP) , São Paulo , Brazil
| | - Cristhianna V Collares
- Molecular Immunogenetics Group, Department of Genetics, Ribeirão Preto Medical School, University of São Paulo (USP) , São Paulo , Brazil
| | - Ana Carolina Freitas
- Department of Pathology, Ribeirão Preto Medical School, University of São Paulo (USP) , São Paulo , Brazil
| | - Paula Barbim Donate
- Molecular Immunogenetics Group, Department of Genetics, Ribeirão Preto Medical School, University of São Paulo (USP) , São Paulo , Brazil
| | - Elza T Sakamoto-Hojo
- Department of Biology, Faculty of Philosophy, Sciences and Letters of Ribeirão Preto, University of São Paulo (USP) , São Paulo , Brazil
| | - Eduardo A Donadi
- Department of Clinical Medicine, Division of Clinical Immunology, Ribeirão Preto Medical School, University of São Paulo (USP) , São Paulo , Brazil
| | - Geraldo A Passos
- Molecular Immunogenetics Group, Department of Genetics, Ribeirão Preto Medical School, University of São Paulo (USP), São Paulo, Brazil; Discipline of Genetics and Molecular Biology, Department of Morphology, Physiology and Basic Pathology, School of Dentistry of Ribeirão Preto, University of São Paulo (USP), São Paulo, Brazil
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5
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Colobran R, Giménez-Barcons M, Marín-Sánchez A, Porta-Pardo E, Pujol-Borrell R. AIRE genetic variants and predisposition to polygenic autoimmune disease: The case of Graves' disease and a systematic literature review. Hum Immunol 2016; 77:643-651. [PMID: 27266815 DOI: 10.1016/j.humimm.2016.06.002] [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: 11/30/2015] [Revised: 05/20/2016] [Accepted: 06/03/2016] [Indexed: 12/25/2022]
Abstract
Autoimmune Regulator (AIRE) is a transcriptional regulator that is crucial for establishing central tolerance as illustrated by the Mendelian Autoimmune Polyendocrinopathy-Candidiasis-Ectodermal Dystrophy (APECED) syndrome associated with AIRE-inactivating recessive or dominant mutations. Polymorphisms in AIRE have been proposed to be implicated in genetic susceptibility to non-Mendelian organ specific autoimmune diseases. Because there is evidence that in predisposition to Graves' disease (GD) central tolerance is crucial, we investigated whether AIRE polymorphisms could modulate risk of GD. A case-control association study using 29 variants and conducted in 150 GD patients and 200 controls did not detect any significant association. This result is not exceptional: a systematic review of the literature, including GWAS, on the association of AIRE variants with organ specific autoimmune diseases did not show clear associations; similarly heterozygous recessive mutations are not associated to non-Mendelian autoimmunity. Dominant negative mutations of AIRE are associated to autoimmunity but as mild forms of APECED rather than to non-Mendelian organ specific autoimmunity. The lack of association of common AIRE polymorphisms with polygenic autoimmune diseases is counterintuitive as many other genes less relevant for immunological tolerance have been found to be associated. These findings give rise to the intriguing possibility that evolution has excluded functionally modifying polymorphisms in AIRE.
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Affiliation(s)
- Roger Colobran
- Immunology Division, Hospital Universitari Vall d'Hebron (HUVH), Vall d'Hebron Research Institute (VHIR), Barcelona 08035, Catalonia, Spain; Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona (UAB), Bellaterra 08193, Catalonia, Spain
| | - Mireia Giménez-Barcons
- Immunology Division, Hospital Universitari Vall d'Hebron (HUVH), Vall d'Hebron Research Institute (VHIR), Barcelona 08035, Catalonia, Spain
| | - Ana Marín-Sánchez
- Immunology Division, Hospital Universitari Vall d'Hebron (HUVH), Vall d'Hebron Research Institute (VHIR), Barcelona 08035, Catalonia, Spain
| | - Eduard Porta-Pardo
- Bioinformatics and Systems Biology Program, Sanford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Ricardo Pujol-Borrell
- Immunology Division, Hospital Universitari Vall d'Hebron (HUVH), Vall d'Hebron Research Institute (VHIR), Barcelona 08035, Catalonia, Spain; Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona (UAB), Bellaterra 08193, Catalonia, Spain.
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6
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Loss of Pten Disrupts the Thymic Epithelium and Alters Thymic Function. PLoS One 2016; 11:e0149430. [PMID: 26914657 PMCID: PMC4767252 DOI: 10.1371/journal.pone.0149430] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 01/20/2016] [Indexed: 11/19/2022] Open
Abstract
The thymus is the site of T cell development and selection. In addition to lymphocytes, the thymus is composed of several types of stromal cells that are exquisitely organized to create the appropriate environment and microenvironment to support the development and selection of maturing T cells. Thymic epithelial cells (TECs) are one of the more important cell types in the thymic stroma, and they play a critical role in selecting functional T cell clones and supporting their development. In this study, we used a mouse genetics approach to investigate the consequences of deleting the Pten tumor suppressor gene in the TEC compartment of the developing thymus. We found that PTEN deficiency in TECs results in a smaller thymus with significantly disordered architecture and histology. Accordingly, loss of PTEN function also results in decreased T cells with a shift in the distribution of T cell subtypes towards CD8+ T cells. These experiments demonstrate that PTEN is critically required for the development of a functional thymic epithelium in mice. This work may help better understand the effects that certain medical conditions or clinical interventions have upon the thymus and immune function.
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7
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Passos GA, Mendes-da-Cruz DA, Oliveira EH. The Thymic Orchestration Involving Aire, miRNAs, and Cell-Cell Interactions during the Induction of Central Tolerance. Front Immunol 2015; 6:352. [PMID: 26236310 PMCID: PMC4500981 DOI: 10.3389/fimmu.2015.00352] [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: 05/15/2015] [Accepted: 06/29/2015] [Indexed: 01/23/2023] Open
Abstract
Developing thymocytes interact sequentially with two distinct structures within the thymus: the cortex and medulla. Surviving single-positive and double-positive thymocytes from the cortex migrate into the medulla, where they interact with medullary thymic epithelial cells (mTECs). These cells ectopically express a vast set of peripheral tissue antigens (PTAs), a property termed promiscuous gene expression that is associated with the presentation of PTAs by mTECs to thymocytes. Thymocyte clones that have a high affinity for PTAs are eliminated by apoptosis in a process termed negative selection, which is essential for tolerance induction. The Aire gene is an important factor that controls the expression of a large set of PTAs. In addition to PTAs, Aire also controls the expression of miRNAs in mTECs. These miRNAs are important in the organization of the thymic architecture and act as posttranscriptional controllers of PTAs. Herein, we discuss recent discoveries and highlight open questions regarding the migration and interaction of developing thymocytes with thymic stroma, the ectopic expression of PTAs by mTECs, the association between Aire and miRNAs and its effects on central tolerance.
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Affiliation(s)
- Geraldo Aleixo Passos
- Molecular Immunogenetics Group, Department of Genetics, Ribeirão Preto Medical School, University of São Paulo , Ribeirão Preto, São Paulo , Brazil ; Disciplines of Genetics and Molecular Biology, Department of Morphology, Physiology and Basic Pathology, School of Dentistry of Ribeirão Preto, University of São Paulo , Ribeirão Preto, São Paulo , Brazil
| | - Daniella Arêas Mendes-da-Cruz
- Laboratory on Thymus Research, Oswaldo Cruz Institute, Oswaldo Cruz Foundation , Rio de Janeiro, Rio de Janeiro , Brazil
| | - Ernna Hérida Oliveira
- Molecular Immunogenetics Group, Department of Genetics, Ribeirão Preto Medical School, University of São Paulo , Ribeirão Preto, São Paulo , Brazil
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Nitta T, Muro R, Shimizu Y, Nitta S, Oda H, Ohte Y, Goto M, Yanobu-Takanashi R, Narita T, Takayanagi H, Yasuda H, Okamura T, Murata S, Suzuki H. The thymic cortical epithelium determines the TCR repertoire of IL-17-producing γδT cells. EMBO Rep 2015; 16:638-53. [PMID: 25770130 DOI: 10.15252/embr.201540096] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Accepted: 02/18/2015] [Indexed: 12/31/2022] Open
Abstract
The thymus provides a specialized microenvironment in which distinct subsets of thymic epithelial cells (TECs) support T-cell development. Here, we describe the significance of cortical TECs (cTECs) in T-cell development, using a newly established mouse model of cTEC deficiency. The deficiency of mature cTECs caused a massive loss of thymic cellularity and impaired the development of αβT cells and invariant natural killer T cells. Unexpectedly, the differentiation of certain γδT-cell subpopulations-interleukin-17-producing Vγ4 and Vγ6 cells-was strongly dysregulated, resulting in the perturbation of γδT-mediated inflammatory responses in peripheral tissues. These findings show that cTECs contribute to the shaping of the TCR repertoire, not only of "conventional" αβT cells but also of inflammatory "innate" γδT cells.
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Affiliation(s)
- Takeshi Nitta
- Department of Immunology and Pathology, Research Institute, National Center for Global Health and Medicine, Chiba, Japan
| | - Ryunosuke Muro
- Department of Immunology and Pathology, Research Institute, National Center for Global Health and Medicine, Chiba, Japan
| | - Yukiko Shimizu
- Department of Laboratory Animal Medicine, Research Institute, National Center for Global Health and Medicine, Tokyo, Japan
| | - Sachiko Nitta
- Department of Immunology and Pathology, Research Institute, National Center for Global Health and Medicine, Chiba, Japan
| | - Hiroyo Oda
- Department of Immunology and Pathology, Research Institute, National Center for Global Health and Medicine, Chiba, Japan
| | - Yuki Ohte
- Laboratory of Protein Metabolism, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Motohito Goto
- Department of Laboratory Animal Medicine, Research Institute, National Center for Global Health and Medicine, Tokyo, Japan
| | - Rieko Yanobu-Takanashi
- Department of Laboratory Animal Medicine, Research Institute, National Center for Global Health and Medicine, Tokyo, Japan
| | - Tomoya Narita
- Department of Immunology, Graduate School of Medicine and Faculty of Medicine, The University of Tokyo, Tokyo, Japan
| | - Hiroshi Takayanagi
- Department of Immunology, Graduate School of Medicine and Faculty of Medicine, The University of Tokyo, Tokyo, Japan
| | - Hisataka Yasuda
- Bioindustry Division, Oriental Yeast Co., Ltd., Tokyo, Japan
| | - Tadashi Okamura
- Department of Laboratory Animal Medicine, Research Institute, National Center for Global Health and Medicine, Tokyo, Japan Section of Animal Models, Department of Infectious Diseases, Research Institute National Center for Global Health and Medicine, Tokyo, Japan
| | - Shigeo Murata
- Laboratory of Protein Metabolism, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Harumi Suzuki
- Department of Immunology and Pathology, Research Institute, National Center for Global Health and Medicine, Chiba, Japan
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Ucar A, Ucar O, Klug P, Matt S, Brunk F, Hofmann TG, Kyewski B. Adult thymus contains FoxN1(-) epithelial stem cells that are bipotent for medullary and cortical thymic epithelial lineages. Immunity 2014; 41:257-69. [PMID: 25148026 PMCID: PMC4148705 DOI: 10.1016/j.immuni.2014.07.005] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Accepted: 06/13/2014] [Indexed: 12/15/2022]
Abstract
Within the thymus, two major thymic epithelial cell (TEC) subsets—cortical and medullary TECs—provide unique structural and functional niches for T cell development and establishment of central tolerance. Both lineages are believed to originate from a common progenitor cell, yet the cellular and molecular identity of these bipotent TEC progenitors/stem cells remains ill defined. Here we identify rare stromal cells in the murine adult thymus, which under low-attachment conditions formed spheres (termed “thymospheres”). These thymosphere-forming cells (TSFCs) displayed the stemness features of being slow cycling, self-renewing, and bipotent. TSFCs could be significantly enriched based on their distinct surface antigen phenotype. The FoxN1 transcription factor was dispensable for TSFCs maintenance in situ and for commitment to the medullary and cortical TEC lineages. In summary, this study presents the characterization of the adult thymic epithelial stem cells and demonstrates the dispensability of FoxN1 function for their stemness. Adult thymic epithelium contains thymosphere-forming stem cells (TSFCs) TSFCs give rise to both thymic epithelial lineages in vitro and in vivo TSFCs are maintained in the absence of functional FoxN1 Lineage commitment in the sphere is FoxN1 independent
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Affiliation(s)
- Ahmet Ucar
- Division of Developmental Immunology, German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany; Cellular Senescence Group, German Cancer Research Center (DKFZ), DKFZ-ZMBH Alliance, 69120 Heidelberg, Germany
| | - Olga Ucar
- Division of Developmental Immunology, German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
| | - Paula Klug
- Division of Developmental Immunology, German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
| | - Sonja Matt
- Cellular Senescence Group, German Cancer Research Center (DKFZ), DKFZ-ZMBH Alliance, 69120 Heidelberg, Germany
| | - Fabian Brunk
- Division of Developmental Immunology, German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
| | - Thomas G Hofmann
- Cellular Senescence Group, German Cancer Research Center (DKFZ), DKFZ-ZMBH Alliance, 69120 Heidelberg, Germany.
| | - Bruno Kyewski
- Division of Developmental Immunology, German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany.
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Giménez-Barcons M, Casteràs A, Armengol MDP, Porta E, Correa PA, Marín A, Pujol-Borrell R, Colobran R. Autoimmune predisposition in Down syndrome may result from a partial central tolerance failure due to insufficient intrathymic expression of AIRE and peripheral antigens. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2014; 193:3872-9. [PMID: 25217160 DOI: 10.4049/jimmunol.1400223] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2023]
Abstract
Down syndrome (DS), or trisomy of chromosome 21, is the most common genetic disorder associated with autoimmune diseases. Autoimmune regulator protein (AIRE), a transcription factor located on chromosome 21, plays a crucial role in autoimmunity by regulating promiscuous gene expression (pGE). To investigate if autoimmunity in DS is promoted by the reduction of pGE owing to dysregulation of AIRE, we assessed the expression of AIRE and of several peripheral tissue-restricted Ag genes by quantitative PCR in thymus samples from 19 DS subjects and 21 euploid controls. Strikingly, despite the 21 trisomy, AIRE expression was significantly reduced by 2-fold in DS thymuses compared with controls, which was also confirmed by fluorescent microscopy. Allele-specific quantification of intrathymic AIRE showed that despite its lower expression, the three copies are expressed. More importantly, decreased expression of AIRE was accompanied by a reduction of pGE because expression of tissue-restricted Ags, CHRNA1, GAD1, PLP1, KLK3, SAG, TG, and TSHR, was reduced. Of interest, thyroid dysfunction (10 cases of hypothyroidism and 1 of Graves disease) developed in 11 of 19 (57.9%) of the DS individuals and in none of the 21 controls. The thymuses of these DS individuals contained significantly lower levels of AIRE and thyroglobulin, to which tolerance is typically lost in autoimmune thyroiditis leading to hypothyroidism. Our findings provide strong evidence for the fundamental role of AIRE and pGE, namely, central tolerance, in the predisposition to autoimmunity of DS individuals.
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Affiliation(s)
- Mireia Giménez-Barcons
- Divisió d'Immunologia, Hospital Universitari Vall d'Hebron, Vall d'Hebron Institut de Recerca, Barcelona 08035, Spain
| | - Anna Casteràs
- Divisió d'Endocrinologia, Hospital Universitari Vall d'Hebron, Vall d'Hebron Institut de Recerca, Barcelona 08035, Spain
| | - Maria del Pilar Armengol
- Institut d'Investigació en Ciències de la Salut Germans Trias i Pujol, Badalona 08916, Spain; and
| | - Eduard Porta
- Institut d'Investigació en Ciències de la Salut Germans Trias i Pujol, Badalona 08916, Spain; and
| | - Paula A Correa
- Institut d'Investigació en Ciències de la Salut Germans Trias i Pujol, Badalona 08916, Spain; and
| | - Ana Marín
- Divisió d'Immunologia, Hospital Universitari Vall d'Hebron, Vall d'Hebron Institut de Recerca, Barcelona 08035, Spain
| | - Ricardo Pujol-Borrell
- Divisió d'Immunologia, Hospital Universitari Vall d'Hebron, Vall d'Hebron Institut de Recerca, Barcelona 08035, Spain; Departament de Biologia Cellular, de Fisiologia i d'Immunologia, Universitat Autònoma de Barcelona, Bellaterra 08193, Spain
| | - Roger Colobran
- Divisió d'Immunologia, Hospital Universitari Vall d'Hebron, Vall d'Hebron Institut de Recerca, Barcelona 08035, Spain; Departament de Biologia Cellular, de Fisiologia i d'Immunologia, Universitat Autònoma de Barcelona, Bellaterra 08193, Spain
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11
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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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12
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Bredenkamp N, Nowell CS, Blackburn CC. Regeneration of the aged thymus by a single transcription factor. Development 2014; 141:1627-37. [PMID: 24715454 PMCID: PMC3978836 DOI: 10.1242/dev.103614] [Citation(s) in RCA: 127] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Thymic involution is central to the decline in immune system function that occurs with age. By regenerating the thymus, it may therefore be possible to improve the ability of the aged immune system to respond to novel antigens. Recently, diminished expression of the thymic epithelial cell (TEC)-specific transcription factor Forkhead box N1 (FOXN1) has been implicated as a component of the mechanism regulating age-related involution. The effects of upregulating FOXN1 function in the aged thymus are, however, unknown. Here, we show that forced, TEC-specific upregulation of FOXN1 in the fully involuted thymus of aged mice results in robust thymus regeneration characterized by increased thymopoiesis and increased naive T cell output. We demonstrate that the regenerated organ closely resembles the juvenile thymus in terms of architecture and gene expression profile, and further show that this FOXN1-mediated regeneration stems from an enlarged TEC compartment, rebuilt from progenitor TECs. Collectively, our data establish that upregulation of a single transcription factor can substantially reverse age-related thymic involution, identifying FOXN1 as a specific target for improving thymus function and, thus, immune competence in patients. More widely, they demonstrate that organ regeneration in an aged mammal can be directed by manipulation of a single transcription factor, providing a provocative paradigm that may be of broad impact for regenerative biology.
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Affiliation(s)
- Nicholas Bredenkamp
- Medical Research Council Centre for Regenerative Medicine, Institute for Stem Cell Research, School of Biological Sciences, University of Edinburgh, SCRM Building, 5 Little France Drive, Edinburgh EH16 4UU, UK
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13
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Xu X, Ge Q. Maturation and migration of murine CD4 single positive thymocytes and thymic emigrants. Comput Struct Biotechnol J 2014; 9:e201403003. [PMID: 24757506 PMCID: PMC3995209 DOI: 10.5936/csbj.201403003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Revised: 03/18/2014] [Accepted: 03/23/2014] [Indexed: 11/22/2022] Open
Abstract
T lymphopoiesis in the thymus was thought to be completed once they reach the single positive (SP) stage, when they are “fully mature” and wait to be exported at random or follow a “first in-first out” manner. Recently, accumulating evidence has revealed that newly generated SP thymocytes undergo further maturation in the thymic medulla before they follow a tightly regulated emigrating process to become recent thymic emigrants (RTEs). RTEs in the periphery then experience a post-thymic maturation and peripheral tolerance and eventually become licensed as mature naïve T cells. This review summarizes the recent progress in the late stage T cell development in and outside of the thymus. The regulation of this developmental process is also discussed.
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Affiliation(s)
- Xi Xu
- Key Laboratory of Medical Immunology, Ministry of Health. Department of Immunology, School of Basic Medical Sciences, Peking University Health Science Center, 38 Xue Yuan Road, Beijing 100191, P R China
| | - Qing Ge
- Key Laboratory of Medical Immunology, Ministry of Health. Department of Immunology, School of Basic Medical Sciences, Peking University Health Science Center, 38 Xue Yuan Road, Beijing 100191, P R China
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14
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Danzl NM, Jeong S, Choi Y, Alexandropoulos K. Identification of novel thymic epithelial cell subsets whose differentiation is regulated by RANKL and Traf6. PLoS One 2014; 9:e86129. [PMID: 24465914 PMCID: PMC3897650 DOI: 10.1371/journal.pone.0086129] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2013] [Accepted: 12/10/2013] [Indexed: 12/31/2022] Open
Abstract
Thymic epithelial cells (TECs) are critical for the normal development and function of the thymus. Here, we examined the developmental stages of TECs using quantitative assessment of the cortical and medullary markers Keratin 5 and Keratin 8 (K5 and K8) respectively, in normal and gain/loss of function mutant animals. Gain of function mice overexpressed RANKL in T cells, whereas loss of function animals lacked expression of Traf6 in TECs (Traf6ΔTEC). Assessment of K5 and K8 expression in conjunction with other TEC markers in wild type mice identified novel cortical and medullary TEC populations, expressing different combinations of these markers. RANKL overexpression led to expansion of all medullary TECs (mTECs) and enlargement of the thymic medulla. This in turn associated with a block in thymocyte development and loss of CD4+ CD8+, CD4+ and CD8+ thymocytes. In contrast, Traf6 deletion inhibited the production of most TEC populations including cortical TECs (cTECs), defined by absence of UEA-1 binding and LY51 expression, but had no apparent effect on thymocyte development. These results reveal a large degree of heterogeneity within the TEC compartment and the existence of several populations exhibiting concomitant expression of cortical, medullary and epithelial markers and whose production is regulated by RANKL and Traf6.
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Affiliation(s)
- Nichole M. Danzl
- Columbia Center for Translational Immunology, Columbia University Medical Center, New York, New York, United States of America
| | - Seihwan Jeong
- Department of Medicine, Division of Clinical Immunology, The Immunology Institute, Icahn School of Medicine at Mount Sinai, New York, New York, United States of America
| | - Yongwon Choi
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Konstantina Alexandropoulos
- Department of Medicine, Division of Clinical Immunology, The Immunology Institute, Icahn School of Medicine at Mount Sinai, New York, New York, United States of America
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15
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Maturation and emigration of single-positive thymocytes. Clin Dev Immunol 2013; 2013:282870. [PMID: 24187562 PMCID: PMC3804360 DOI: 10.1155/2013/282870] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Accepted: 09/01/2013] [Indexed: 01/01/2023]
Abstract
T lymphopoiesis in the thymus was thought to be completed once it reaches the single positive (SP)
stage, a stage when T cells are “fully mature” and waiting to be exported at random or follow a “first-in-first-out” manner. Recent evidence, however, has revealed that the newly generated SP thymocytes undergo a multistage maturation program in the thymic medulla. Such maturation is followed by a tightly regulated emigration process and a further postthymic maturation of recent thymic emigrants (RTEs). This review summarizes recent progress in the late stage T cell development. The regulation of this developmental process is discussed.
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16
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Sun L, Li H, Luo H, Zhang L, Hu X, Yang T, Sun C, Chen H, Zhang L, Zhao Y. Phosphatase Wip1 Is Essential for the Maturation and Homeostasis of Medullary Thymic Epithelial Cells in Mice. THE JOURNAL OF IMMUNOLOGY 2013; 191:3210-20. [DOI: 10.4049/jimmunol.1300363] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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17
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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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18
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Abstract
Uveitis is underappreciated as a sight-threatening cause of blindness. There are two broad causative classes of uveitis: infectious and non-infectious. Non-infectious uveitis is considered a prototypical autoimmune disorder based mainly on data from experimental models in the mouse. Several different experimental models exist that reflect the different types of uveitis in man (anterior, intermediate, and posterior uveitis). These models have demonstrated that uveitis is predominantly a Th1/Th17 mediated disease, although innate immune cells play a significant role both in induction of disease and in tissue damage. Most experimental models of uveitis rely on activation of the innate immune system by use of adjuvants that activate a range of pathogen recognition receptors (PRRs). This begs the question of the underlying role of initial and/or persistent infection, including latent infection, in immune-mediated uveitis in which active infection cannot be demonstrated. This further raises the possibility of pathogenic mechanisms such as antigenic cross-reactivity and molecular mimicry. Alternatively, residual/latent antigen from infectious agents may act as "endogenous" adjuvants for induction of immune reactions to damaged/altered self antigen, suggesting a commonality in pathogenesis for both infectious and non-infectious uveitis in man.
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Affiliation(s)
- John V Forrester
- Ocular Immunology Laboratory, Section of Immunology and Infection, Division of Applied Medicine, Institute of Medical Sciences, University of Aberdeen, Scotland.
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19
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Ucar O, Tykocinski LO, Dooley J, Liston A, Kyewski B. An evolutionarily conserved mutual interdependence between Aire and microRNAs in promiscuous gene expression. Eur J Immunol 2013; 43:1769-78. [PMID: 23589212 PMCID: PMC3816332 DOI: 10.1002/eji.201343343] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2013] [Revised: 03/12/2013] [Accepted: 04/11/2013] [Indexed: 11/11/2022]
Abstract
The establishment and maintenance of central tolerance depends to a large extent on the ability of medullary thymic epithelial cells to express a variety of tissue-restricted antigens, the so-called promiscuous gene expression (pGE). Autoimmune regulator (Aire) is to date the best characterised transcriptional regulator known to at least partially coordinate pGE. There is accruing evidence that the expression of Aire-dependent and -independent genes is modulated by higher order chromatin configuration, epigenetic modifications and post-transcriptional control. Given the involvement of microRNAs (miRNAs) as potent post-transcriptional modulators of gene expression, we investigated their role in the regulation of pGE in purified mouse and human thymic epithelial cells (TECs). Microarray profiling of TEC subpopulations revealed evolutionarily conserved cell type and differentiation-specific miRNA signatures with a subset of miRNAs being significantly upregulated during terminal medullary thymic epithelial cell differentiation. The differential regulation of this subset of miRNAs was correlated with Aire expression and some of these miRNAs were misexpressed in the Aire knockout thymus. In turn, the specific absence of miRNAs in TECs resulted in a progressive reduction of Aire expression and pGE, affecting both Aire-dependent and -independent genes. In contrast, the absence of miR-29a only affected the Aire-dependent gene pool. These findings reveal a mutual interdependence of miRNA and Aire.
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Affiliation(s)
- Olga Ucar
- Division of Developmental Immunology, German Cancer Research CenterHeidelberg, Germany
| | | | - James Dooley
- Autoimmune Genetics Laboratory, VIBLeuven, Belgium
- Department of Microbiology and Immunology, University of LeuvenLeuven, Belgium
| | - Adrian Liston
- Autoimmune Genetics Laboratory, VIBLeuven, Belgium
- Department of Microbiology and Immunology, University of LeuvenLeuven, Belgium
| | - Bruno Kyewski
- Division of Developmental Immunology, German Cancer Research CenterHeidelberg, Germany
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20
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Macedo C, Evangelista AF, Marques MM, Octacílio-Silva S, Donadi EA, Sakamoto-Hojo ET, Passos GA. Autoimmune regulator (Aire) controls the expression of microRNAs in medullary thymic epithelial cells. Immunobiology 2013; 218:554-60. [PMID: 22883565 DOI: 10.1016/j.imbio.2012.06.013] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2012] [Revised: 06/25/2012] [Accepted: 06/26/2012] [Indexed: 01/12/2023]
Abstract
The autoimmune regulator (Aire) is a transcription factor that controls the ectopic expression of a large set of peripheral tissue antigen (PTA) genes in medullary thymic epithelial cells (mTECs). Recent evidence has demonstrated that Aire releases stalled RNA polymerase II (RNA Pol II) from blockage at the promoter region of its target genes. Given that, in addition to messenger RNAs (mRNA), RNA Pol II also transcribes microRNAs (miRNAs), we raised the hypothesis that Aire might play a role as an upstream controller of miRNA transcription. To test this, we initially analyzed the expression profiles of 662 miRNAs in control and Aire-silenced (siRNA) murine mTEC 3.10 cells using microarrays. The bioinformatics programs SAM and Cluster-TreeView were then used to identify the differentially expressed miRNAs and their profiles, respectively. Thirty Aire-dependent miRNAs were identified in the Aire-silenced mTECs, of which 18 were up- and 12 were down-regulated. The down-regulated miR-376 family was the focus of this study because its members (miR-376a, miR-376b and miR-376c) are located in the genome within the Gm2922 open-reading frame (ORF) gene segment on the chromosome 12F1. The T-boxes (TTATTA) and G-boxes (GATTGG), which represent putative RNA Pol II promoter motifs, were located in a portion spanning 10 kb upstream of the ATG codon of Gm2922. Moreover, we found that Gm2922 encodes an mRNA, which was also down-regulated in Aire-silenced mTECs. These results represent the first evidence that Aire can play a role as a controller of transcription of miRNAs located within genomic regions encompassing ORF and/or mRNA genes.
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Affiliation(s)
- Claudia Macedo
- Molecular Immunogenetics Group, Department of Genetics, Faculty of Medicine of Ribeirão Preto, University of São Paulo (USP), 14040-900 Ribeirão Preto, SP, Brazil
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21
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Oliveira EH, Macedo C, Donate PB, Almeida RS, Pezzi N, Nguyen C, Rossi MA, Sakamoto-Hojo ET, Donadi EA, Passos GA. Expression profile of peripheral tissue antigen genes in medullary thymic epithelial cells (mTECs) is dependent on mRNA levels of autoimmune regulator (Aire). Immunobiology 2013; 218:96-104. [PMID: 22564670 DOI: 10.1016/j.imbio.2012.02.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2011] [Revised: 02/02/2012] [Accepted: 02/07/2012] [Indexed: 12/25/2022]
Abstract
In the thymus of non-obese diabetic (NOD) mice, the expression of the autoimmune regulator (Aire) gene varies with age, and its down-regulation in young mice precedes the later emergence of type 1 diabetes mellitus (T1D). In addition, the insulin (Ins2) peripheral tissue antigen (PTA) gene, which is Aire-dependent, is also deregulated in these mice. Based in these findings, we hypothesized that the imbalance in PTA gene expression in the thymus can be associated with slight variations in Aire transcript levels. To test this, we used siRNA to knockdown Aire by in vivo electro-transfection of the thymus of BALB/c mice. The efficiency of the electro-transfection was monitored by assessing the presence of irrelevant Cy3-labeled siRNA in the thymic stroma. Importantly, Aire-siRNA reached medullary thymic epithelial cells (mTECs) down-regulating Aire. As expected, the in vivo Aire knockdown was partial and transient; the maximum 59% inhibition occurred in 48 h. The Aire knockdown was sufficient to down-regulate PTA genes; however, surprisingly, several others, including Ins2, were up-regulated. The modulation of these genes after in vivo Aire knockdown was comparable to that observed in NOD mice before the emergence of T1D. The in vitro transfections of 3.10 mTEC cells with Aire siRNA resulted in samples featuring partial (69%) and complete (100%) Aire knockdown. In these Aire siRNA-transfected 3.10 mTECs, the expression of PTA genes, including Ins2, was down-regulated. This suggests that the expression profile of PTA genes in mTECs is affected by fine changes in the transcription level of Aire.
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Affiliation(s)
- Ernna H Oliveira
- Molecular Immunogenetics Group, Department of Genetics, Faculty of Medicine of Ribeirão Preto, University of São Paulo (USP), 14040-900 Ribeirão Preto, SP, Brazil
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22
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Perniola R. Expression of the autoimmune regulator gene and its relevance to the mechanisms of central and peripheral tolerance. Clin Dev Immunol 2012; 2012:207403. [PMID: 23125865 PMCID: PMC3485510 DOI: 10.1155/2012/207403] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2012] [Revised: 08/26/2012] [Accepted: 09/11/2012] [Indexed: 01/12/2023]
Abstract
The autoimmune polyendocrine syndrome type 1 (APS-1) is a monogenic disease due to pathogenic variants occurring in the autoimmune regulator (AIRE) gene. Its related protein, AIRE, activates the transcription of genes encoding for tissue-specific antigens (TsAgs) in a subset of medullary thymic epithelial cells: the presentation of TsAgs to the maturating thymocytes induces the apoptosis of the autoreactive clones and constitutes the main form of central tolerance. Dysregulation of thymic AIRE expression in genetically transmitted and acquired diseases other than APS-1 may contribute to further forms of autoimmunity. As AIRE and its murine homolog are also expressed in the secondary lymphoid organs, the extent and relevance of AIRE participation in the mechanisms of peripheral tolerance need to be thoroughly defined.
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Affiliation(s)
- Roberto Perniola
- Neonatal Intensive Care, Department of Pediatrics, V. Fazzi Regional Hospital, Piazza F. Muratore, 73100 Lecce, Italy.
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23
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Alexandropoulos K, Danzl NM. Thymic epithelial cells: antigen presenting cells that regulate T cell repertoire and tolerance development. Immunol Res 2012; 54:177-90. [DOI: 10.1007/s12026-012-8301-y] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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24
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Dzhagalov I, Phee H. How to find your way through the thymus: a practical guide for aspiring T cells. Cell Mol Life Sci 2011; 69:663-82. [PMID: 21842411 DOI: 10.1007/s00018-011-0791-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2011] [Revised: 07/25/2011] [Accepted: 07/25/2011] [Indexed: 01/16/2023]
Abstract
Thymocytes must complete an elaborate developmental program in the thymus to ultimately generate T cells that express functional but neither harmful nor useless TCRs. Each developmental step coincides with dynamic relocation of the thymocytes between anatomically discrete thymic microenvironments, suggesting that thymocytes' migration is tightly regulated by their developmental status. Chemokines produced by thymic stromal cells and chemokine receptors on the thymocytes play an indispensable role in guiding developing thymocytes into the different microenvironments. In addition to long-range migration, chemokines increase the thymocytes' motility, enhancing their interaction with stromal cells. During the past several years, much progress has been made to determine the various signals that guide thymocytes on their journey within the thymus. In this review, we summarize the progress in identifying chemokines and other chemoattractant signals that direct intrathymic migration. Furthermore, we discuss the recent advances of two-photon microscopy in determining dynamic motility and interaction behavior of thymocytes within distinct compartments to provide a better understanding of the relationship between thymocyte motility and development.
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Affiliation(s)
- Ivan Dzhagalov
- LSA, Room 479, Department of Molecular and Cell Biology, Division of Immunology and Pathogenesis, University of California Berkeley, Berkeley, CA 94720-3200, USA.
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25
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Abstract
Despite the monumental success of childhood prophylactic vaccination, there is no similar program designed to provide protection as we age against adult onset diseases like breast cancer. Instead, the predominant focus of current cancer vaccine strategy is to vaccinate after the tumors become established. This strategy has at best provided incremental improvement in overall survival. We propose the development of an adult vaccination program modeled on the childhood program that provides protection against diseases we confront as we enter our middle age. Since most cases of adult cancers are not associated with definitive etiopathogenic viruses, we propose extending our selection of vaccine targets to tissue-specific self proteins that are over-expressed in developing tumors but are no longer expressed in normal tissues ('retired or former self'), are expressed in normal tissues under readily avoidable conditions ('conditional self'), or are incapable of targeting any clinically significant autoimmune complications ('irrelevant self'). By extending prophylactic vaccination to such "functional non-self" targets, prophylactic vaccination against adult onset diseases like breast cancer may occur safely in the absence of any autoimmune inflammatory complications and may potentially reduce disease incidence in a manner that mimics the impact of childhood vaccination on diseases like measles and polio.
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Affiliation(s)
- Vincent K Tuohy
- Department of Immunology, Lerner Research Institute, Cleveland Clinic, Ohio, USA.
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26
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Kroger CJ, Flores RR, Morillon M, Wang B, Tisch R. Dysregulation of thymic clonal deletion and the escape of autoreactive T cells. Arch Immunol Ther Exp (Warsz) 2010; 58:449-57. [PMID: 20872284 DOI: 10.1007/s00005-010-0100-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2010] [Accepted: 06/25/2010] [Indexed: 12/25/2022]
Abstract
Events ongoing in the thymus are critical for deleting developing thymocytes specific for tissue antigens, and establishing self-tolerance within the T cell compartment. Aberrant thymic negative selection, however, is believed to generate a repertoire with increased self-reactivity, which in turn can contribute to the development of T cell-mediated autoimmunity. In this review, mechanisms that regulate the efficacy of negative selection and influence the deletion of autoreactive thymocytes will be discussed.
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Affiliation(s)
- Charles J Kroger
- Department of Microbiology and Immunology, University of North Carolina, Mary Ellen Jones Bldg., Room 635, Campus Box 7290, Chapel Hill, NC 27599-7290, USA
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27
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Zhu M, Brown NK, Fu YX. Direct and indirect roles of the LTbetaR pathway in central tolerance induction. Trends Immunol 2010; 31:325-31. [PMID: 20675191 DOI: 10.1016/j.it.2010.06.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2009] [Revised: 06/19/2010] [Accepted: 06/22/2010] [Indexed: 12/30/2022]
Abstract
Medullary thymic epithelial cells (mTECs) play a critical role in thymic negative selection of autoreactive thymocytes, especially for thymocytes specific for peripheral tissue-restricted self-antigens (TRA). Deficiency in lymphotoxin b receptor (LTbetaR) is associated with peripheral tissue inflammation, but whether this is caused by defective negative selection has been unclear; the significance of the LTbetaR pathway for negative selection is evident in some models but not others. Here, we revisit the data and clarify the role of LTbetaR in mTEC development and function and thymic TRA expression. These processes are discussed as potential mechanisms for LTbetaR-mediated control of negative selection.
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Affiliation(s)
- Mingzhao Zhu
- Key Laboratory of Infection and Immunity, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
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28
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Ryan SO, Turner MS, Gariépy J, Finn OJ. Tumor antigen epitopes interpreted by the immune system as self or abnormal-self differentially affect cancer vaccine responses. Cancer Res 2010; 70:5788-96. [PMID: 20587526 DOI: 10.1158/0008-5472.can-09-4519] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Epitope selection is an important consideration in the design of cancer vaccines, but factors affecting selection are not fully understood. We compared the immune responses to peptides and glycopeptides from the common human tumor antigen MUC1, a mucin that is coated with O-linked carbohydrates in its variable number of tandem repeats (VNTR) region. MUC1 expressed on tumor cells is characteristically underglycosylated, creating peptide and glycopeptide neoepitopes that are recognized by the immune system. The response to VNTR peptides is weaker in MUC1-transgenic mice (MUC1-Tg mice) than in wild-type (WT) mice, whereas the response to VNTR glycopeptides is equally strong in the two strains. Thus, glycopeptides seem to be recognized as foreign, whereas peptides, although immunogenic, are perceived as self. To explore this further, we generated MUC1 peptide- and glycopeptide-specific T-cell receptor transgenic mice and studied the function of their CD4 T cells when adoptively transferred into MUC1-Tg or WT mice. Peptide-specific T-cell precursors were not centrally deleted in MUC1-Tg mice and did not acquire a T regulatory phenotype. However, their response to the cognate peptide was reduced in MUC1-Tg mice compared with WT mice. In contrast, glycopeptide-specific CD4 T cells responded equally well in the two hosts and, when simultaneously activated, also enhanced the peptide-specific T-cell responses. Our data show that the immune system differentially recognizes various epitopes of tumor-associated antigens either as self or as foreign, and this controls the strength of antitumor immunity. This represents an important consideration for designing safe and effective cancer vaccines.
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Affiliation(s)
- Sean O Ryan
- Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15262, USA
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29
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Alexandropoulos K, Regelmann AG. Regulation of T-lymphocyte physiology by the Chat-H/CasL adapter complex. Immunol Rev 2010; 232:160-74. [PMID: 19909363 DOI: 10.1111/j.1600-065x.2009.00831.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The Cas family of proteins consists of at least four members implicated in the regulation of diverse cellular processes such as cell proliferation, adhesion, motility, and cancer cell metastasis. Cas family members have conserved C-termini that mediate constitutive heterotypic interactions with members of a different group of proteins, the NSP family. Both the Cas and NSP proteins have conserved domains that mediate protein-protein interactions with other cytoplasmic intermediates. Signaling modules assembled by these proteins in turn regulate signal transduction downstream of a variety of receptors including integrin, chemokine, and antigen receptors. T lymphocytes express the NSP protein NSP3/Chat-H and the Cas protein Hef1/CasL, which are found in a constitutive complex in naive T cells. We recently showed that Chat-H and Hef1/CasL regulate integrin-mediated adhesion and promote T-cell migration and trafficking downstream of activated chemokine receptors. It is currently unclear if the Chat-H/CasL module also plays a role in antigen receptor signaling. Here we review our current knowledge of how Chat-H and Hef1/CasL regulate T-cell physiology and whether this protein complex plays a functional role downstream of T-cell receptor activation.
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Affiliation(s)
- Konstantina Alexandropoulos
- Department of Medicine, Division of Clinical Immunology, The Immunology Institute, Mount Sinai School of Medicine, New York, NY 10029, USA.
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30
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Abstract
PURPOSE OF REVIEW Severe combined immunodeficiencies represent a heterogeneous group of genetic disorders affecting genes of both early and late steps in lymphocytes development, a process tightly controlled by thymic epithelial cells. Detailed analysis of thymic morphology aids to the assessment of the severity of the immune disorder and may be critical to the understanding of the role of the genetic defects in the pathophysiology of these diseases. In this review, we highlight recent advancements in the characterization of the thymic microenvironment in primary immunodeficiencies. RECENT FINDINGS Crosstalk between thymocytes and thymic epithelial cells is essential to preserve thymic architecture and function, and therefore to promote T-cell maturation and development of self-tolerance. Early severe defects in T-cell development result in profound abnormalities of thymic epithelial cells differentiation with loss of AIRE expression and severe reduction of thymic dendritic and T-regulatory cells. Differently, later defects in T-cell development that are permissive for normal thymocytes development allow cortico-medullary differentiation with partially preserved AIRE expression and dendritic/T-regulatory cells distribution. Hypomorphic mutations in the same genes partially permissive to T-cell development may result in a more complex phenotype with immunodysreactivity and peculiar thymic alterations. SUMMARY Although the molecular and genetic bases of primary immunodeficiencies directly aid to both diagnosis and management of the patients, the detailed analysis of thymic morphology critically contributes to unveil the pathophysiology of these diseases.
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Danzl NM, Donlin LT, Alexandropoulos K. Regulation of medullary thymic epithelial cell differentiation and function by the signaling protein Sin. ACTA ACUST UNITED AC 2010; 207:999-1013. [PMID: 20404100 PMCID: PMC2867288 DOI: 10.1084/jem.20092384] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Medullary thymic epithelial cells (mTECs) play an important role in T cell tolerance and prevention of autoimmunity. Mice deficient in expression of the signaling protein Sin exhibit exaggerated immune responses and multitissue inflammation. Here, we show that Sin is expressed in the thymic stroma, specifically in mTECs. Sin deficiency led to thymic stroma-dependent autoimmune manifestations shown by radiation chimeras and thymic transplants in nude mice, and associated with defective mTEC-mediated elimination of thymocytes in a T cell receptor transgenic model of negative selection. Lack of Sin expression correlated with a disorganized medullary architecture and fewer functionally mature mTECs under steady-state conditions. Additionally, Sin deficiency inhibited the expansion of mTECs in response to in vivo administration of keratinocyte growth factor (KGF). These results identify Sin as a novel regulator of mTEC development and T cell tolerance, and suggest that Sin is important for homeostatic maintenance of the medullary epithelium in the adult thymus.
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Affiliation(s)
- Nichole M Danzl
- Department of Pharmacology, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
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Abstract
This article focuses on the functions of NF-kappaB that vitally impact lymphocytes and thus adaptive immunity. NF-kappaB has long been known to be essential for many of the responses of mature lymphocytes to invading pathogens. In addition, NF-kappaB has important functions in shaping the immune system so it is able to generate adaptive responses to pathogens. In both contexts, NF-kappaB executes critical cell-autonomous functions within lymphocytes as well as within supportive cells, such as antigen-presenting cells or epithelial cells. It is these aspects of NF-kappaB's physiologic impact that we address in this article.
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Ehrlich LIR, Oh DY, Weissman IL, Lewis RS. Differential contribution of chemotaxis and substrate restriction to segregation of immature and mature thymocytes. Immunity 2009; 31:986-98. [PMID: 19962328 DOI: 10.1016/j.immuni.2009.09.020] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2009] [Revised: 08/30/2009] [Accepted: 09/21/2009] [Indexed: 12/24/2022]
Abstract
T cell development requires sequential localization of thymocyte subsets to distinct thymic microenvironments. To address mechanisms governing this segregation, we used two-photon microscopy to visualize migration of purified thymocyte subsets in defined microenvironments within thymic slices. Double-negative (CD4(-)8(-)) and double-positive (CD4(+)8(+)) thymocytes were confined to cortex where they moved slowly without directional bias. DP cells accumulated and migrated more rapidly in a specialized inner-cortical microenvironment, but were unable to migrate on medullary substrates. In contrast, CD4 single positive (SP) thymocytes migrated directionally toward the medulla, where they accumulated and moved very rapidly. Our results revealed a requisite two-step process governing CD4 SP cell medullary localization: the chemokine receptor CCR7 mediated chemotaxis of CD4 SP cells towards medulla, whereas a distinct pertussis-toxin sensitive pathway was required for medullary entry. These findings suggest that developmentally regulated responses to both chemotactic signals and specific migratory substrates guide thymocytes to specific locations in the thymus.
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Affiliation(s)
- Lauren I Richie Ehrlich
- Institute for Stem Cell Biology and Regenerative Medicine, Stanford University, Stanford, CA 94305, USA
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Macedo C, Evangelista AF, Magalhães DA, Fornari TA, Linhares LL, Junta CM, Silva GL, Sakamoto-Hojo ET, Donadi EA, Savino W, Passos GAS. Evidence for a network transcriptional control of promiscuous gene expression in medullary thymic epithelial cells. Mol Immunol 2009; 46:3240-4. [PMID: 19720399 DOI: 10.1016/j.molimm.2009.08.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2009] [Revised: 08/04/2009] [Accepted: 08/04/2009] [Indexed: 11/17/2022]
Abstract
The expression of peripheral tissue antigens (PTAs) in the thymus by medullary thymic epithelial cells (mTECs) is essential for the central self-tolerance in the generation of the T cell repertoire. Due to heterogeneity of autoantigen representation, this phenomenon has been termed promiscuous gene expression (PGE), in which the autoimmune regulator (Aire) gene plays a key role as a transcription factor in part of these genes. Here we used a microarray strategy to access PGE in cultured murine CD80(+) 3.10 mTEC line. Hierarchical clustering of the data allowed observation that PTA genes were differentially expressed being possible to found their respective induced or repressed mRNAs. To further investigate the control of PGE, we tested the hypothesis that genes involved in this phenomenon might also be modulated by transcriptional network. We then reconstructed such network based on the microarray expression data, featuring the guanylate cyclase 2d (Gucy2d) gene as a main node. In such condition, we established 167 positive and negative interactions with downstream PTA genes. Silencing Aire by RNA interference, Gucy2d while down regulated established a larger number (355) of interactions with PTA genes. T- and G-boxes corresponding to AIRE protein binding sites located upstream to ATG codon of Gucy2d supports this effect. These findings provide evidence that Aire plays a role in association with Gucy2d, which is connected to several PTA genes and establishes a cascade-like transcriptional control of promiscuous gene expression in mTEC cells.
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Affiliation(s)
- Cláudia Macedo
- Molecular Immunogenetics Group, Department of Genetics, Faculty of Medicine of Ribeirão Preto, University of São Paulo (USP), Ribeirão Preto, SP, Brazil
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