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Park CS, Guan J, Rhee P, Gonzalez F, Lee HS, Park JH, Coscoy L, Robey EA, Shastri N, Sadegh-Nasseri S. Fam49b dampens TCR signal strength to regulate survival of positively selected thymocytes and peripheral T cells. eLife 2024; 13:e76940. [PMID: 39158947 PMCID: PMC11333044 DOI: 10.7554/elife.76940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 07/16/2024] [Indexed: 08/20/2024] Open
Abstract
The fate of developing T cells is determined by the strength of T cell receptor (TCR) signal they receive in the thymus. This process is finely regulated through the tuning of positive and negative regulators in thymocytes. The Family with sequence similarity 49 member B (Fam49b) protein is a newly discovered negative regulator of TCR signaling that has been shown to suppress Rac-1 activity in vitro in cultured T cell lines. However, the contribution of Fam49b to the thymic development of T cells is unknown. To investigate this important issue, we generated a novel mouse line deficient in Fam49b (Fam49b-KO). We observed that Fam49b-KO double positive (DP) thymocytes underwent excessive negative selection, whereas the positive selection stage was unaffected. Fam49b deficiency impaired the survival of single positive thymocytes and peripheral T cells. This altered development process resulted in significant reductions in CD4 and CD8 single-positive thymocytes as well as peripheral T cells. Interestingly, a large proportion of the TCRγδ+ and CD8αα+TCRαβ+ gut intraepithelial T lymphocytes were absent in Fam49b-KO mice. Our results demonstrate that Fam49b dampens thymocytes TCR signaling in order to escape negative selection during development, uncovering the function of Fam49b as a critical regulator of the selection process to ensure normal thymocyte development and peripheral T cells survival.
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Affiliation(s)
- Chan-Su Park
- Department of Pathology, The Johns Hopkins University School of MedicineBaltimoreUnited States
- Department of Pharmaceutics, College of Pharmacy, Chungbuk National UniversityCheongjuRepublic of Korea
| | - Jian Guan
- Department of Pathology, The Johns Hopkins University School of MedicineBaltimoreUnited States
| | - Peter Rhee
- Department of Pathology, The Johns Hopkins University School of MedicineBaltimoreUnited States
| | - Federico Gonzalez
- Department of Nutritional Sciences and Toxicology, University of California,BerkeleyBerkeleyUnited States
| | - Hee-sung Lee
- Department of Pharmaceutics, College of Pharmacy, Chungbuk National UniversityCheongjuRepublic of Korea
| | - Ji-hyun Park
- Department of Pharmaceutics, College of Pharmacy, Chungbuk National UniversityCheongjuRepublic of Korea
| | - Laurent Coscoy
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
| | - Ellen A Robey
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
| | - Nilabh Shastri
- Department of Pathology, The Johns Hopkins University School of MedicineBaltimoreUnited States
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Pardini E, Barachini S, Alì G, Infirri GS, Burzi IS, Montali M, Petrini I. Single-cell sequencing has revealed a more complex array of thymic epithelial cells. Immunol Lett 2024; 269:106904. [PMID: 39117004 DOI: 10.1016/j.imlet.2024.106904] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2024] [Revised: 07/23/2024] [Accepted: 07/29/2024] [Indexed: 08/10/2024]
Abstract
Thymic epithelial cells participate in the maturation and selection of T lymphocytes. This review explores recent insights from single-cell sequencing regarding classifying thymic epithelial cells in both normal and neoplastic thymus. Cortical thymic epithelial cells facilitate thymocyte differentiation and contribute to positive selection. Medullary epithelial cells are distinguished by their expression of AIRE. Cells progress from a pre-AIRE state, containing precursors with cortical and medullary characteristics, termed junctional cells. Mature medullary epithelial cells exhibit promiscuous gene expression and after that downregulate AIRE mRNA. Post-AIRE cells can adopt a Hassall corpuscle-like phenotype or exhibit distinctive differentiation characteristics including tuft cells, ionocytes, neuroendocrine cells, and myoid cells.
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Affiliation(s)
- Eleonora Pardini
- Department of Translational Research and New Surgical and Medical Technologies, University of Pisa, Pisa, Italy
| | - Serena Barachini
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy.
| | - Greta Alì
- Department of Surgical, Medical and Molecular Pathology and Critical Care Medicine, Pisa, Italy
| | - Gisella Sardo Infirri
- Department of Translational Research and New Surgical and Medical Technologies, University of Pisa, Pisa, Italy
| | - Irene Sofia Burzi
- Department of Translational Research and New Surgical and Medical Technologies, University of Pisa, Pisa, Italy
| | - Marina Montali
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Iacopo Petrini
- Department of Translational Research and New Surgical and Medical Technologies, University of Pisa, Pisa, Italy
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Belean A, Xue E, Cisneros B, Roberson EDO, Paley MA, Bigley TM. Transcriptomic profiling of thymic dysregulation and viral tropism after neonatal roseolovirus infection. Front Immunol 2024; 15:1375508. [PMID: 38895117 PMCID: PMC11183875 DOI: 10.3389/fimmu.2024.1375508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Accepted: 05/10/2024] [Indexed: 06/21/2024] Open
Abstract
Introduction Herpesviruses, including the roseoloviruses, have been linked to autoimmune disease. The ubiquitous and chronic nature of these infections have made it difficult to establish a causal relationship between acute infection and subsequent development of autoimmunity. We have shown that murine roseolovirus (MRV), which is highly related to human roseoloviruses, induces thymic atrophy and disruption of central tolerance after neonatal infection. Moreover, neonatal MRV infection results in development of autoimmunity in adult mice, long after resolution of acute infection. This suggests that MRV induces durable immune dysregulation. Methods In the current studies, we utilized single-cell RNA sequencing (scRNAseq) to study the tropism of MRV in the thymus and determine cellular processes in the thymus that were disrupted by neonatal MRV infection. We then utilized tropism data to establish a cell culture system. Results Herein, we describe how MRV alters the thymic transcriptome during acute neonatal infection. We found that MRV infection resulted in major shifts in inflammatory, differentiation and cell cycle pathways in the infected thymus. We also observed shifts in the relative number of specific cell populations. Moreover, utilizing expression of late viral transcripts as a proxy of viral replication, we identified the cellular tropism of MRV in the thymus. This approach demonstrated that double negative, double positive, and CD4 single positive thymocytes, as well as medullary thymic epithelial cells were infected by MRV in vivo. Finally, by applying pseudotime analysis to viral transcripts, which we refer to as "pseudokinetics," we identified viral gene transcription patterns associated with specific cell types and infection status. We utilized this information to establish the first cell culture systems susceptible to MRV infection in vitro. Conclusion Our research provides the first complete picture of roseolovirus tropism in the thymus after neonatal infection. Additionally, we identified major transcriptomic alterations in cell populations in the thymus during acute neonatal MRV infection. These studies offer important insight into the early events that occur after neonatal MRV infection that disrupt central tolerance and promote autoimmune disease.
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Affiliation(s)
- Andrei Belean
- Division of Rheumatology, Department of Medicine, Washington University School of Medicine, St. Louis, MO, United States
| | - Eden Xue
- Division of Rheumatology, Department of Pediatrics, Washington University School of Medicine, St. Louis, MO, United States
| | - Benjamin Cisneros
- Division of Rheumatology, Department of Pediatrics, Washington University School of Medicine, St. Louis, MO, United States
| | - Elisha D. O. Roberson
- Division of Rheumatology, Department of Medicine, Washington University School of Medicine, St. Louis, MO, United States
- Division of Rheumatology, Department of Pediatrics, Washington University School of Medicine, St. Louis, MO, United States
- Department of Genetics, Washington University School of Medicine, St. Louis, MO, United States
| | - Michael A. Paley
- Division of Rheumatology, Department of Medicine, Washington University School of Medicine, St. Louis, MO, United States
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, United States
| | - Tarin M. Bigley
- Division of Rheumatology, Department of Pediatrics, Washington University School of Medicine, St. Louis, MO, United States
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, United States
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, United States
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Badr ME, Zhang Z, Tai X, Singer A. CD8 T cell tolerance results from eviction of immature autoreactive cells from the thymus. Science 2023; 382:534-541. [PMID: 37917689 PMCID: PMC11302524 DOI: 10.1126/science.adh4124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Accepted: 09/22/2023] [Indexed: 11/04/2023]
Abstract
CD8 T cell tolerance is thought to result from clonal deletion of autoreactive thymocytes before they differentiate into mature CD8 T cells in the thymus. However, we report that, in mice, CD8 T cell tolerance instead results from premature thymic eviction of immature autoreactive CD8 thymocytes into the periphery, where they differentiate into self-tolerant mature CD8 T cells. Premature thymic eviction is triggered by T cell receptor (TCR)-driven down-regulation of the transcriptional repressor Gfi1, which induces expression of sphingosine-1-phosphate receptor-1 (S1P1) on negatively selected immature CD8 thymocytes. Thus, premature thymic eviction is the basis for CD8 T cell tolerance and is the mechanism responsible for the appearance in the periphery of mature CD8 T cells bearing autoreactive TCRs that are absent from the thymus.
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Affiliation(s)
- Mohamed Elsherif Badr
- Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Zhongmei Zhang
- Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Xuguang Tai
- Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Alfred Singer
- Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
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Taves MD, Donahue KM, Bian J, Cam MC, Ashwell JD. Aire drives steroid hormone biosynthesis by medullary thymic epithelial cells. Sci Immunol 2023; 8:eabo7975. [PMID: 37595021 PMCID: PMC10732315 DOI: 10.1126/sciimmunol.abo7975] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Accepted: 07/25/2023] [Indexed: 08/20/2023]
Abstract
Thymic epithelial cells (TECs) produce glucocorticoids, which antagonize negative selection of autoreactive thymocytes and promote a competent T cell antigen-specific repertoire. To characterize their source, we generated a knock-in reporter mouse in which endogenous Cyp11b1, the final enzyme in de novo production of active glucocorticoids, was fluorescently tagged with mScarlet. Here, we find that Cyp11b1 is expressed in medullary TECs (mTECs) but not cortical TECs or other cells in the thymus. A distinct characteristic of mTECs is the presence of Aire, a transcription factor that drives expression of tissue-restricted antigens (TRAs) important for establishing immune tolerance. Cyp11b1 expression was highest in Aire+ mTECs, lower in post-Aire mTECs, and absent in mTECs of Aire-deficient mice. Transcriptomic analyses found that multiple enzymatic biosynthetic pathways are expressed specifically in mTECs and are also Aire dependent. In particular, we found that the thymus expresses messenger RNA for enzymes that catalyze production of many bioactive steroids and that glucocorticoids and sex steroids were secreted by cultured thymi. Expression of the transcripts for these genes and production of their final steroid products were markedly reduced in the absence of Aire. Thus, in addition to its well-established role in inducing TRAs that promote negative selection, Aire has an additional and contrary function of inducing glucocorticoids that antagonize negative selection, which together may expand and enhance the TCR repertoire. Furthermore, because Aire drives expression of multiple enzymes responsible for production of other non-gene-encoded bioactive molecules, it might have yet other roles in thymus development and function.
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Affiliation(s)
- Matthew D. Taves
- Laboratory of Immune Cell Biology, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA
| | - Kaitlynn M. Donahue
- Laboratory of Immune Cell Biology, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA
| | - Jing Bian
- CCR Collaborative Bioinformatics Resource, Center for Cancer Research, Bethesda, MD 20892, USA
| | - Margaret C. Cam
- CCR Collaborative Bioinformatics Resource, Center for Cancer Research, Bethesda, MD 20892, USA
| | - Jonathan D. Ashwell
- Laboratory of Immune Cell Biology, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA
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6
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Bosselut R. A Beginner's Guide to T Cell Development. Methods Mol Biol 2023; 2580:3-24. [PMID: 36374448 DOI: 10.1007/978-1-0716-2740-2_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
T lymphocytes (T cells) are essential components of the adaptive immune system; they serve multiple functions in responses to pathogens and to ensure immune homeostasis. Written for readers first entering this field of study, this chapter is a brief overview of the development of T cells in the thymus, from the entry of thymus-settling bone marrow-derived precursors to the egress of mature T cells. Surveyed topics include the differentiation and expansion of early precursors, the generation of the T cell antigen receptor repertoire, the selection of αβ T cell precursors, and their acquisition of functional competency.
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Affiliation(s)
- Rémy Bosselut
- Laboratory of Immune Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA.
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7
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Chopp L, Redmond C, O'Shea JJ, Schwartz DM. From thymus to tissues and tumors: A review of T-cell biology. J Allergy Clin Immunol 2023; 151:81-97. [PMID: 36272581 PMCID: PMC9825672 DOI: 10.1016/j.jaci.2022.10.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 10/10/2022] [Accepted: 10/13/2022] [Indexed: 11/05/2022]
Abstract
T cells are critical orchestrators of the adaptive immune response that optimally eliminate a specific pathogen. Aberrant T-cell development and function are implicated in a broad range of human disease including immunodeficiencies, autoimmune diseases, and allergic diseases. Accordingly, therapies targeting T cells and their effector cytokines have markedly improved the care of patients with immune dysregulatory diseases. Newer discoveries concerning T-cell-mediated antitumor immunity and T-cell exhaustion have further prompted development of highly effective and novel treatment modalities for malignancies, including checkpoint inhibitors and antigen-reactive T cells. Recent discoveries are also uncovering the depth and variability of T-cell phenotypes: while T cells have long been described using a subset-based classification system, next-generation sequencing technologies suggest an astounding degree of complexity and heterogeneity at the single-cell level.
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Affiliation(s)
- Laura Chopp
- Laboratory of Immune Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda
| | - Christopher Redmond
- Clinical Fellowship Program, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda
| | - John J O'Shea
- Molecular Immunology and Inflammation Branch, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda
| | - Daniella M Schwartz
- Laboratory of Allergic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda; Division of Rheumatology and Clinical Immunology, University of Pittsburgh, Pittsburgh.
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Teixeiro E, Daniels MA. Fetal Thymic Organ Culture and Negative Selection. Methods Mol Biol 2023; 2580:293-302. [PMID: 36374465 DOI: 10.1007/978-1-0716-2740-2_18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Negative selection removes potentially harmful T cell precursors from the conventional T cell pool. This process can involve the induction of apoptosis, anergy, receptor editing, or deviation into a regulatory T cell lineage. As such, this process is essential for the health of an organism through its contribution to central and peripheral tolerance. While a great deal is known about the process, the precise mechanisms that regulate these various forms of negative selection are not clear. Numerous models exist with the potential to address these questions in vitro and in vivo. This chapter describes fetal thymic organ culture methods designed to analyze the signals that determine these unique cell fates.
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Affiliation(s)
- Emma Teixeiro
- Department of Molecular Microbiology and Immunology, NextGen Precision Health, University of Missouri, Columbia, MO, USA
| | - Mark A Daniels
- Department of Molecular Microbiology and Immunology, NextGen Precision Health, University of Missouri, Columbia, MO, USA.
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Semwal MK, Hester AK, Xiao Y, Udeaja C, Cepeda S, Verschelde JS, Jones N, Wedemeyer SA, Emtage S, Wimberly K, Griffith AV. Redox status regulates autophagy in thymic stromal cells and promotes T cell tolerance. Proc Natl Acad Sci U S A 2022; 119:e2204296119. [PMID: 36161925 PMCID: PMC9549397 DOI: 10.1073/pnas.2204296119] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Accepted: 08/30/2022] [Indexed: 11/18/2022] Open
Abstract
Thymic stromal cells (TSCs) are critical regulators of T cell tolerance, but their basic biology has remained under-characterized because they are relatively rare and difficult to isolate. Recent work has revealed that constitutive autophagy in TSCs is required for self-antigen presentation and central T cell tolerance induction; however, the mechanisms regulating constitutive autophagy in TSCs are not well understood. Hydrogen peroxide has been shown to increase autophagy flux in other tissues, and we previously identified conspicuously low expression of the hydrogen peroxide-quenching enzyme catalase in TSCs. We investigated whether the redox status of TSCs established by low catalase expression regulates their basal autophagy levels and their capacity to impose central T cell tolerance. Transgenic overexpression of catalase diminished autophagy in TSCs and impaired thymocyte clonal deletion, concomitant with increased frequencies of spontaneous lymphocytic infiltrates in lung and liver and of serum antinuclear antigen reactivity. Effects on clonal deletion and autoimmune indicators were diminished in catalase transgenic mice when autophagy was rescued by expression of the Becn1F121A/F121A knock-in allele. These results suggest a metabolic mechanism by which the redox status of TSCs may regulate central T cell tolerance.
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Affiliation(s)
- Manpreet K. Semwal
- Department of Microbiology, Immunology and Molecular Genetics, University of Texas Long School of Medicine, UT Health San Antonio, San Antonio, TX 78229
- Barshop Institute for Longevity and Aging Studies, UT Health San Antonio, San Antonio, TX 78229
| | - Allison K. Hester
- Department of Microbiology, Immunology and Molecular Genetics, University of Texas Long School of Medicine, UT Health San Antonio, San Antonio, TX 78229
- Department of Medicine, Blood and Marrow Transplantation Division, Stanford University, Stanford, CA 94305
| | - Yangming Xiao
- Department of Microbiology, Immunology and Molecular Genetics, University of Texas Long School of Medicine, UT Health San Antonio, San Antonio, TX 78229
| | - Chioma Udeaja
- Department of Microbiology, Immunology and Molecular Genetics, University of Texas Long School of Medicine, UT Health San Antonio, San Antonio, TX 78229
| | - Sergio Cepeda
- Department of Immunology, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - John S. Verschelde
- Department of Microbiology, Immunology and Molecular Genetics, University of Texas Long School of Medicine, UT Health San Antonio, San Antonio, TX 78229
| | - Nicholas Jones
- Department of Microbiology, Immunology and Molecular Genetics, University of Texas Long School of Medicine, UT Health San Antonio, San Antonio, TX 78229
| | - Sarah A. Wedemeyer
- Department of Microbiology, Immunology and Molecular Genetics, University of Texas Long School of Medicine, UT Health San Antonio, San Antonio, TX 78229
| | - Simon Emtage
- Department of Microbiology, Immunology and Molecular Genetics, University of Texas Long School of Medicine, UT Health San Antonio, San Antonio, TX 78229
| | - Kymberly Wimberly
- Department of Microbiology, Immunology and Molecular Genetics, University of Texas Long School of Medicine, UT Health San Antonio, San Antonio, TX 78229
| | - Ann V. Griffith
- Department of Microbiology, Immunology and Molecular Genetics, University of Texas Long School of Medicine, UT Health San Antonio, San Antonio, TX 78229
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Majumdar S, Lin Y, Bettini ML. Host-microbiota interactions shaping T-cell response and tolerance in type 1 diabetes. Front Immunol 2022; 13:974178. [PMID: 36059452 PMCID: PMC9434376 DOI: 10.3389/fimmu.2022.974178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Accepted: 07/25/2022] [Indexed: 11/29/2022] Open
Abstract
Type-1 Diabetes (T1D) is a complex polygenic autoimmune disorder involving T-cell driven beta-cell destruction leading to hyperglycemia. There is no cure for T1D and patients rely on exogenous insulin administration for disease management. T1D is associated with specific disease susceptible alleles. However, the predisposition to disease development is not solely predicted by them. This is best exemplified by the observation that a monozygotic twin has just a 35% chance of developing T1D after their twin’s diagnosis. This makes a strong case for environmental triggers playing an important role in T1D incidence. Multiple studies indicate that commensal gut microbiota and environmental factors that alter their composition might exacerbate or protect against T1D onset. In this review, we discuss recent literature highlighting microbial species associated with T1D. We explore mechanistic studies which propose how some of these microbial species can modulate adaptive immune responses in T1D, with an emphasis on T-cell responses. We cover topics ranging from gut-thymus and gut-pancreas communication, microbial regulation of peripheral tolerance, to molecular mimicry of islet antigens by microbial peptides. In light of the accumulating evidence on commensal influences in neonatal thymocyte development, we also speculate on the link between molecular mimicry and thymic selection in the context of T1D pathogenesis. Finally, we explore how these observations could inform future therapeutic approaches in this disease.
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Affiliation(s)
- Shubhabrata Majumdar
- Immunology Graduate Program, Baylor College of Medicine, Houston, TX, United States
- Department of Pathology, University of Utah, Salt Lake City, UT, United States
| | - Yong Lin
- Immunology Graduate Program, Baylor College of Medicine, Houston, TX, United States
- Department of Pathology, University of Utah, Salt Lake City, UT, United States
| | - Matthew L. Bettini
- Department of Pathology, University of Utah, Salt Lake City, UT, United States
- *Correspondence: Matthew L. Bettini,
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11
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Wang C, Daley SR. How Thymocyte Deletion in the Cortex May Curtail Antigen-Specific T-Regulatory Cell Development in the Medulla. Front Immunol 2022; 13:892498. [PMID: 35693793 PMCID: PMC9176388 DOI: 10.3389/fimmu.2022.892498] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 04/26/2022] [Indexed: 11/13/2022] Open
Abstract
CD4+ T cell responses to self-antigens are pivotal for immunological self-tolerance. Activation of Foxp3– T-conventional (T-conv) cells can precipitate autoimmune disease, whereas activation of Foxp3+ T-regulatory (T-reg) cells is essential to prevent autoimmune disease. This distinction indicates the importance of the thymus in controlling the differentiation of self-reactive CD4+ T cells. Thymocytes and thymic antigen-presenting cells (APC) depend on each other for normal maturation and differentiation. In this Hypothesis and Theory article, we propose this mutual dependence dictates which self-antigens induce T-reg cell development in the thymic medulla. We postulate self-reactive CD4+ CD8– thymocytes deliver signals that stabilize and amplify the presentation of their cognate self-antigen by APC in the thymic medulla, thereby seeding a niche for the development of T-reg cells specific for the same self-antigen. By limiting the number of antigen-specific CD4+ thymocytes in the medulla, thymocyte deletion in the cortex may impede the formation of medullary T-reg niches containing certain self-antigens. Susceptibility to autoimmune disease may arise from cortical deletion creating a “hole” in the self-antigen repertoire recognized by T-reg cells.
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Affiliation(s)
- Chenglong Wang
- Centre for Immunology and Infection Control, School of Biomedical Sciences, Faculty of Health, Queensland University of Technology, Brisbane, QLD, Australia
| | - Stephen R Daley
- Centre for Immunology and Infection Control, School of Biomedical Sciences, Faculty of Health, Queensland University of Technology, Brisbane, QLD, Australia
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12
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Březina J, Vobořil M, Filipp D. Mechanisms of Direct and Indirect Presentation of Self-Antigens in the Thymus. Front Immunol 2022; 13:926625. [PMID: 35774801 PMCID: PMC9237256 DOI: 10.3389/fimmu.2022.926625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 05/16/2022] [Indexed: 11/13/2022] Open
Abstract
The inevitability of evolution of the adaptive immune system with its mechanism of randomly rearranging segments of the T cell receptor (TCR) gene is the generation of self-reactive clones. For the sake of prevention of autoimmunity, these clones must be eliminated from the pool of circulating T cells. This process occurs largely in the thymic medulla where the strength of affinity between TCR and self-peptide MHC complexes is the factor determining thymocyte fate. Thus, the display of self-antigens in the thymus by thymic antigen presenting cells, which are comprised of medullary thymic epithelial (mTECs) and dendritic cells (DCs), is fundamental for the establishment of T cell central tolerance. Whereas mTECs produce and present antigens in a direct, self-autonomous manner, thymic DCs can acquire these mTEC-derived antigens by cooperative antigen transfer (CAT), and thus present them indirectly. While the basic characteristics for both direct and indirect presentation of self-antigens are currently known, recent reports that describe the heterogeneity of mTEC and DC subsets, their presentation capacity, and the potentially non-redundant roles in T cell selection processes represents another level of complexity which we are attempting to unravel. In this review, we underscore the seminal studies relevant to these topics with an emphasis on new observations pertinent to the mechanism of CAT and its cellular trajectories underpinning the preferential distribution of thymic epithelial cell-derived self-antigens to specific subsets of DC. Identification of molecular determinants which control CAT would significantly advance our understanding of how the cellularly targeted presentation of thymic self-antigens is functionally coupled to the T cell selection process.
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Affiliation(s)
| | | | - Dominik Filipp
- Laboratory of Immunobiology, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czechia
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Abstract
A high diversity of αβ T cell receptors (TCRs), capable of recognizing virtually any pathogen but also self-antigens, is generated during T cell development in the thymus. Nevertheless, a strict developmental program supports the selection of a self-tolerant T cell repertoire capable of responding to foreign antigens. The steps of T cell selection are controlled by cortical and medullary stromal niches, mainly composed of thymic epithelial cells and dendritic cells. The integration of important cues provided by these specialized niches, including (a) the TCR signal strength induced by the recognition of self-peptide-MHC complexes, (b) costimulatory signals, and (c) cytokine signals, critically controls T cell repertoire selection. This review discusses our current understanding of the signals that coordinate positive selection, negative selection, and agonist selection of Foxp3+ regulatory T cells. It also highlights recent advances that have unraveled the functional diversity of thymic antigen-presenting cell subsets implicated in T cell selection.
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Affiliation(s)
- Magali Irla
- Centre d'Immunologie de Marseille-Luminy (CIML), CNRS, INSERM, Aix-Marseille Université, Marseille, France;
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14
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Dong M, Chang J, Lebel MÈ, Gervais N, Fournier M, Mallet Gauthier È, Suh WK, Melichar HJ. The ICOS-ICOSL pathway tunes thymic selection. Immunol Cell Biol 2021; 100:205-217. [PMID: 34962663 PMCID: PMC9304562 DOI: 10.1111/imcb.12520] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2021] [Revised: 12/11/2021] [Accepted: 12/27/2021] [Indexed: 11/30/2022]
Abstract
Negative selection of developing T cells plays a significant role in T cell tolerance to self-antigen. This process relies on thymic antigen presenting cells which express both self-antigens as well as co-signaling molecules. Inducible T cell costimulator (ICOS) belongs to the CD28 family of co-signaling molecules and binds to ICOS ligand (ICOSL). The ICOS signaling pathway plays important roles in shaping the immune response to infections, but its role in central tolerance is less well understood. Here we show that ICOSL is expressed by subsets of thymic dendritic cells and medullary thymic epithelial cells as well as thymic B cells. ICOS expression is upregulated as T cells mature in the thymus and correlates with T cell receptor signal strength during thymic selection. We also provide evidence of a role for ICOS signaling in mediating negative selection. Our findings suggest that ICOS may fine-tune T cell receptor signals during thymic selection contributing to the generation of a tolerant T cell population.
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Affiliation(s)
- Mengqi Dong
- Département de microbiologie, Université de Montréal, infectiologie et immunologie, Montréal, Québec, H3T 1J4, Canada.,Immunology-Oncology Unit, Maisonneuve-Rosemont Hospital Research Center, Montréal, Québec, H1T 2M4, Canada
| | - Jinsam Chang
- Institut de recherches cliniques de Montréal, Montréal, Québec, H2W 1R7, Canada.,Programme de biologie moléculaire, Université de Montréal, Montréal, Québec, H3T 1J4, Canada
| | - Marie-Ève Lebel
- Immunology-Oncology Unit, Maisonneuve-Rosemont Hospital Research Center, Montréal, Québec, H1T 2M4, Canada
| | - Noémie Gervais
- Immunology-Oncology Unit, Maisonneuve-Rosemont Hospital Research Center, Montréal, Québec, H1T 2M4, Canada
| | - Marilaine Fournier
- Immunology-Oncology Unit, Maisonneuve-Rosemont Hospital Research Center, Montréal, Québec, H1T 2M4, Canada
| | - Ève Mallet Gauthier
- Département de microbiologie, Université de Montréal, infectiologie et immunologie, Montréal, Québec, H3T 1J4, Canada.,Immunology-Oncology Unit, Maisonneuve-Rosemont Hospital Research Center, Montréal, Québec, H1T 2M4, Canada
| | - Woong-Kyung Suh
- Département de microbiologie, Université de Montréal, infectiologie et immunologie, Montréal, Québec, H3T 1J4, Canada.,Institut de recherches cliniques de Montréal, Montréal, Québec, H2W 1R7, Canada.,Programme de biologie moléculaire, Université de Montréal, Montréal, Québec, H3T 1J4, Canada
| | - Heather J Melichar
- Immunology-Oncology Unit, Maisonneuve-Rosemont Hospital Research Center, Montréal, Québec, H1T 2M4, Canada.,Département de médecine, Université de Montréal, Montréal, Québec, H3T 1J4, Canada
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15
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Vollmann EH, Rattay K, Barreiro O, Thiriot A, Fuhlbrigge RA, Vrbanac V, Kim KW, Jung S, Tager AM, von Andrian UH. Specialized transendothelial dendritic cells mediate thymic T-cell selection against blood-borne macromolecules. Nat Commun 2021; 12:6230. [PMID: 34711828 PMCID: PMC8553756 DOI: 10.1038/s41467-021-26446-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 09/27/2021] [Indexed: 12/29/2022] Open
Abstract
T cells undergo rigorous selection in the thymus to ensure self-tolerance and prevent autoimmunity, with this process requiring innocuous self-antigens (Ags) to be presented to thymocytes. Self-Ags are either expressed by thymic stroma cells or transported to the thymus from the periphery by migratory dendritic cells (DCs); meanwhile, small blood-borne peptides can access the thymic parenchyma by diffusing across the vascular lining. Here we describe an additional pathway of thymic Ag acquisition that enables circulating antigenic macromolecules to access both murine and human thymi. This pathway depends on a subset of thymus-resident DCs, distinct from both parenchymal and circulating migratory DCs, that are positioned in immediate proximity to thymic microvessels where they extend cellular processes across the endothelial barrier into the blood stream. Transendothelial positioning of DCs depends on DC-expressed CX3CR1 and its endothelial ligand, CX3CL1, and disrupting this chemokine pathway prevents thymic acquisition of circulating proteins and compromises negative selection of Ag-reactive thymocytes. Thus, transendothelial DCs represent a mechanism by which the thymus can actively acquire blood-borne Ags to induce and maintain central tolerance.
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Affiliation(s)
- Elisabeth H Vollmann
- Department of Immunology & HMS Center for Immune Imaging, Harvard Medical School, Boston, MA, 02115, USA
- Merck Research Laboratories, Boston, MA, 02115, USA
| | - Kristin Rattay
- Department of Immunology & HMS Center for Immune Imaging, Harvard Medical School, Boston, MA, 02115, USA
- Institute of Pharmacology, Biochemical Pharmacological Center, University of Marburg, Marburg, Germany
| | - Olga Barreiro
- Department of Immunology & HMS Center for Immune Imaging, Harvard Medical School, Boston, MA, 02115, USA
| | - Aude Thiriot
- Department of Immunology & HMS Center for Immune Imaging, Harvard Medical School, Boston, MA, 02115, USA
| | - Rebecca A Fuhlbrigge
- Department of Immunology & HMS Center for Immune Imaging, Harvard Medical School, Boston, MA, 02115, USA
| | - Vladimir Vrbanac
- Massachusetts General Hospital, Boston, MA, USA
- Massachusetts General Hospital, Humanized Immune System Mouse Program (HISMP), Boston, MA, 02114, USA
| | - Ki-Wook Kim
- Department of Immunology, Weizmann Institute of Science, Rehovot, Israel
- Department of Pharmacology and Regenerative Medicine, University of Illinois College of Medicine, Chicago, IL, 60612, USA
| | - Steffen Jung
- Department of Immunology, Weizmann Institute of Science, Rehovot, Israel
| | | | - Ulrich H von Andrian
- Department of Immunology & HMS Center for Immune Imaging, Harvard Medical School, Boston, MA, 02115, USA.
- Ragon Institute of MGH, MIT and Harvard, Cambridge, MA, USA.
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16
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Lutz MB, Backer RA, Clausen BE. Revisiting Current Concepts on the Tolerogenicity of Steady-State Dendritic Cell Subsets and Their Maturation Stages. THE JOURNAL OF IMMUNOLOGY 2021; 206:1681-1689. [PMID: 33820829 DOI: 10.4049/jimmunol.2001315] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2020] [Accepted: 01/11/2021] [Indexed: 12/25/2022]
Abstract
The original concept stated that immature dendritic cells (DC) act tolerogenically whereas mature DC behave strictly immunogenically. Meanwhile, it is also accepted that phenotypically mature stages of all conventional DC subsets can promote tolerance as steady-state migratory DC by transporting self-antigens to lymph nodes to exert unique functions on regulatory T cells. We propose that in vivo 1) there is little evidence for a tolerogenic function of immature DC during steady state such as CD4 T cell anergy induction, 2) all tolerance as steady-state migratory DC undergo common as well as subset-specific molecular changes, and 3) these changes differ by quantitative and qualitative markers from immunogenic DC, which allows one to clearly distinguish tolerogenic from immunogenic migratory DC.
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Affiliation(s)
- Manfred B Lutz
- Institute for Virology and Immunobiology, University of Würzburg, 97070 Würzburg, Germany; and
| | - Ronald A Backer
- Institute for Molecular Medicine, University Medical Center of the Johannes Gutenberg-University Mainz, 55122 Mainz, Germany
| | - Björn E Clausen
- Institute for Molecular Medicine, University Medical Center of the Johannes Gutenberg-University Mainz, 55122 Mainz, Germany
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17
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Boulet S, Odagiu L, Dong M, Lebel MÈ, Daudelin JF, Melichar HJ, Labrecque N. NR4A3 Mediates Thymic Negative Selection. THE JOURNAL OF IMMUNOLOGY 2021; 207:1055-1064. [PMID: 34312259 DOI: 10.4049/jimmunol.1901228] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Accepted: 06/16/2021] [Indexed: 11/19/2022]
Abstract
Central tolerance aims to limit the production of T lymphocytes bearing TCR with high affinity for self-peptide presented by MHC molecules. The accumulation of thymocytes with such receptors is limited by negative selection or by diversion into alternative differentiation, including T regulatory cell commitment. A role for the orphan nuclear receptor NR4A3 in negative selection has been suggested, but its function in this process has never been investigated. We find that Nr4a3 transcription is upregulated in postselection double-positive thymocytes, particularly those that have received a strong selecting signal and are destined for negative selection. Indeed, we found an accumulation of cells bearing a negative selection phenotype in NR4A3-deficient mice as compared with wild-type controls, suggesting that Nr4a3 transcriptional induction is necessary to limit accumulation of self-reactive thymocytes. This is consistent with a decrease of cleaved caspase-3+-signaled thymocytes and more T regulatory and CD4+Foxp3-HELIOS+ cells in the NR4A3-deficient thymus. We further tested the role for NR4A3 in negative selection by reconstituting transgenic mice expressing the OVA Ag under the control of the insulin promoter with bone marrow cells from OT-I Nr4a3 +/+ or OT-I Nr4a3 -/- mice. Accumulation of autoreactive CD8 thymocytes and autoimmune diabetes developed only in the absence of NR4A3. Overall, our results demonstrate an important role for NR4A3 in T cell development.
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Affiliation(s)
- Salix Boulet
- Maisonneuve-Rosemont Hospital Research Center, Montreal, Quebec, Canada
| | - Livia Odagiu
- Maisonneuve-Rosemont Hospital Research Center, Montreal, Quebec, Canada.,Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Quebec, Canada; and
| | - Mengqi Dong
- Maisonneuve-Rosemont Hospital Research Center, Montreal, Quebec, Canada.,Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Quebec, Canada; and
| | - Marie-Ève Lebel
- Maisonneuve-Rosemont Hospital Research Center, Montreal, Quebec, Canada
| | | | - Heather J Melichar
- Maisonneuve-Rosemont Hospital Research Center, Montreal, Quebec, Canada.,Département de Médecine, Université de Montréal, Montreal, Quebec, Canada
| | - Nathalie Labrecque
- Maisonneuve-Rosemont Hospital Research Center, Montreal, Quebec, Canada; .,Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Quebec, Canada; and.,Département de Médecine, Université de Montréal, Montreal, Quebec, Canada
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18
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Ohigashi I, Takahama Y. Thymoproteasome optimizes positive selection of CD8 + T cells without contribution of negative selection. Adv Immunol 2021; 149:1-23. [PMID: 33993918 DOI: 10.1016/bs.ai.2021.03.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Functionally competent and self-tolerant T cell repertoire is shaped through positive and negative selection in the cortical and medullary microenvironments of the thymus. The thymoproteasome specifically expressed in the cortical thymic epithelium is essential for the optimal generation of CD8+ T cells. Although how the thymoproteasome governs the generation of CD8+ T cells is not fully understood, accumulating evidence suggests that the thymoproteasome optimizes CD8+ T cell production through the processing of self-peptides associated with MHC class I molecules expressed by cortical thymic epithelial cells. In this review, we describe recent advances in the mechanism of thymoproteasome-dependent generation of CD8+ T cells, focusing on the process of cortical positive selection independent of apoptosis-mediated negative selection.
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Affiliation(s)
- Izumi Ohigashi
- Division of Experimental Immunology, Institute of Advanced Medical Sciences, University of Tokushima, Tokushima, Japan
| | - Yousuke Takahama
- Thymus Biology Section, Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, United States.
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19
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Srinivasan J, Lancaster JN, Singarapu N, Hale LP, Ehrlich LIR, Richie ER. Age-Related Changes in Thymic Central Tolerance. Front Immunol 2021; 12:676236. [PMID: 33968086 PMCID: PMC8100025 DOI: 10.3389/fimmu.2021.676236] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Accepted: 04/06/2021] [Indexed: 01/03/2023] Open
Abstract
Thymic epithelial cells (TECs) and hematopoietic antigen presenting cells (HAPCs) in the thymus microenvironment provide essential signals to self-reactive thymocytes that induce either negative selection or generation of regulatory T cells (Treg), both of which are required to establish and maintain central tolerance throughout life. HAPCs and TECs are comprised of multiple subsets that play distinct and overlapping roles in central tolerance. Changes that occur in the composition and function of TEC and HAPC subsets across the lifespan have potential consequences for central tolerance. In keeping with this possibility, there are age-associated changes in the cellular composition and function of T cells and Treg. This review summarizes changes in T cell and Treg function during the perinatal to adult transition and in the course of normal aging, and relates these changes to age-associated alterations in thymic HAPC and TEC subsets.
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Affiliation(s)
- Jayashree Srinivasan
- Department of Molecular Biosciences, Institute of Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX, United States
| | | | - Nandini Singarapu
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas M.D. Anderson Cancer Center, Smithville, TX, United States
| | - Laura P Hale
- Department of Pathology, Duke University School of Medicine, Durham, NC, United States
| | - Lauren I R Ehrlich
- Department of Molecular Biosciences, Institute of Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX, United States.,Livestrong Cancer Institutes, Dell Medical School, The University of Texas at Austin, Austin, TX, United States
| | - Ellen R Richie
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas M.D. Anderson Cancer Center, Smithville, TX, United States
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20
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Kreins AY, Bonfanti P, Davies EG. Current and Future Therapeutic Approaches for Thymic Stromal Cell Defects. Front Immunol 2021; 12:655354. [PMID: 33815417 PMCID: PMC8012524 DOI: 10.3389/fimmu.2021.655354] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Accepted: 03/03/2021] [Indexed: 12/14/2022] Open
Abstract
Inborn errors of thymic stromal cell development and function lead to impaired T-cell development resulting in a susceptibility to opportunistic infections and autoimmunity. In their most severe form, congenital athymia, these disorders are life-threatening if left untreated. Athymia is rare and is typically associated with complete DiGeorge syndrome, which has multiple genetic and environmental etiologies. It is also found in rare cases of T-cell lymphopenia due to Nude SCID and Otofaciocervical Syndrome type 2, or in the context of genetically undefined defects. This group of disorders cannot be corrected by hematopoietic stem cell transplantation, but upon timely recognition as thymic defects, can successfully be treated by thymus transplantation using cultured postnatal thymic tissue with the generation of naïve T-cells showing a diverse repertoire. Mortality after this treatment usually occurs before immune reconstitution and is mainly associated with infections most often acquired pre-transplantation. In this review, we will discuss the current approaches to the diagnosis and management of thymic stromal cell defects, in particular those resulting in athymia. We will discuss the impact of the expanding implementation of newborn screening for T-cell lymphopenia, in combination with next generation sequencing, as well as the role of novel diagnostic tools distinguishing between hematopoietic and thymic stromal cell defects in facilitating the early consideration for thymus transplantation of an increasing number of patients and disorders. Immune reconstitution after the current treatment is usually incomplete with relatively common inflammatory and autoimmune complications, emphasizing the importance for improving strategies for thymus replacement therapy by optimizing the current use of postnatal thymus tissue and developing new approaches using engineered thymus tissue.
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Affiliation(s)
- Alexandra Y. Kreins
- Great Ormond Street Institute of Child Health, University College London, London, United Kingdom
- Department of Immunology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, United Kingdom
| | - Paola Bonfanti
- Great Ormond Street Institute of Child Health, University College London, London, United Kingdom
- Epithelial Stem Cell Biology & Regenerative Medicine Laboratory, The Francis Crick Institute, London, United Kingdom
- Institute of Immunity & Transplantation, University College London, London, United Kingdom
| | - E. Graham Davies
- Great Ormond Street Institute of Child Health, University College London, London, United Kingdom
- Department of Immunology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, United Kingdom
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21
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Nitta T, Takayanagi H. Non-Epithelial Thymic Stromal Cells: Unsung Heroes in Thymus Organogenesis and T Cell Development. Front Immunol 2021; 11:620894. [PMID: 33519827 PMCID: PMC7840694 DOI: 10.3389/fimmu.2020.620894] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2020] [Accepted: 11/27/2020] [Indexed: 12/16/2022] Open
Abstract
The stromal microenvironment in the thymus is essential for generating a functional T cell repertoire. Thymic epithelial cells (TECs) are numerically and phenotypically one of the most prominent stromal cell types in the thymus, and have been recognized as one of most unusual cell types in the body by virtue of their unique functions in the course of the positive and negative selection of developing T cells. In addition to TECs, there are other stromal cell types of mesenchymal origin, such as fibroblasts and endothelial cells. These mesenchymal stromal cells are not only components of the parenchymal and vascular architecture, but also have a pivotal role in controlling TEC development, although their functions have been less extensively explored than TECs. Here, we review both the historical studies on and recent advances in our understanding of the contribution of such non-TEC stromal cells to thymic organogenesis and T cell development. In particular, we highlight the recently discovered functional effect of thymic fibroblasts on T cell repertoire selection.
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Affiliation(s)
- Takeshi Nitta
- Department of Immunology, Graduate School of Medicine and Faculty of Medicine, The University of Tokyo, Tokyo, Japan
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22
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The contribution of thymic tolerance to central nervous system autoimmunity. Semin Immunopathol 2020; 43:135-157. [PMID: 33108502 PMCID: PMC7925481 DOI: 10.1007/s00281-020-00822-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 10/09/2020] [Indexed: 12/15/2022]
Abstract
Autoimmune diseases of the central nervous system (CNS) are associated with high levels of morbidity and economic cost. Research efforts have previously focused on the contribution of the peripheral adaptive and innate immune systems to CNS autoimmunity. However, a failure of thymic negative selection is a necessary step in CNS-reactive T cells escaping into the periphery. Even with defective thymic or peripheral tolerance, the development of CNS inflammation is rare. The reasons underlying this are currently poorly understood. In this review, we examine evidence implicating thymic selection in the pathogenesis of CNS autoimmunity. Animal models suggest that thymic negative selection is an important factor in determining susceptibility to and severity of CNS inflammation. There are indirect clinical data that suggest thymic function is also important in human CNS autoimmune diseases. Specifically, the association between thymoma and paraneoplastic encephalitis and changes in T cell receptor excision circles in multiple sclerosis implicate thymic tolerance in these diseases. We identify potential associations between CNS autoimmunity susceptibility factors and thymic tolerance. The therapeutic manipulation of thymopoiesis has the potential to open up new treatment modalities, but a better understanding of thymic tolerance in CNS autoimmunity is required before this can be realised.
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23
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Tritz ZP, Orozco RC, Malo CS, Ayasoufi K, Fain CE, Khadka RH, Goddery EN, Yokanovich LT, Settell ML, Hansen MJ, Jin F, Pavelko KD, Pease LR, Johnson AJ. Conditional Silencing of H-2D b Class I Molecule Expression Modulates the Protective and Pathogenic Kinetics of Virus-Antigen-Specific CD8 T Cell Responses during Theiler's Virus Infection. THE JOURNAL OF IMMUNOLOGY 2020; 205:1228-1238. [PMID: 32737149 DOI: 10.4049/jimmunol.2000340] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 07/01/2020] [Indexed: 12/15/2022]
Abstract
Theiler's murine encephalomyelitis virus (TMEV) infection of the CNS is cleared in C57BL/6 mice by a CD8 T cell response restricted by the MHC class I molecule H-2Db The identity and function of the APC(s) involved in the priming of this T cell response is (are) poorly defined. To address this gap in knowledge, we developed an H-2Db LoxP-transgenic mouse system using otherwise MHC class I-deficient C57BL/6 mice, thereby conditionally ablating MHC class I-restricted Ag presentation in targeted APC subpopulations. We observed that CD11c+ APCs are critical for early priming of CD8 T cells against the immunodominant TMEV peptide VP2121-130 Loss of H-2Db on CD11c+ APCs mitigates the CD8 T cell response, preventing early viral clearance and immunopathology associated with CD8 T cell activity in the CNS. In contrast, animals with H-2Db-deficient LysM+ APCs retained early priming of Db:VP2121-130 epitope-specific CD8 T cells, although a modest reduction in immune cell entry into the CNS was observed. This work establishes a model enabling the critical dissection of H-2Db-restricted Ag presentation to CD8 T cells, revealing cell-specific and temporal features involved in the generation of CD8 T cell responses. Employing this novel system, we establish CD11c+ cells as pivotal to the establishment of acute antiviral CD8 T cell responses against the TMEV immunodominant epitope VP2121-130, with functional implications both for T cell-mediated viral control and immunopathology.
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Affiliation(s)
- Zachariah P Tritz
- Mayo Clinic Graduate School of Biomedical Sciences, Rochester, MN 55905.,Mayo Clinic Department of Immunology, Rochester, MN 55905
| | - Robin C Orozco
- Mayo Clinic Graduate School of Biomedical Sciences, Rochester, MN 55905.,Mayo Clinic Department of Immunology, Rochester, MN 55905
| | - Courtney S Malo
- Mayo Clinic Graduate School of Biomedical Sciences, Rochester, MN 55905.,Mayo Clinic Department of Immunology, Rochester, MN 55905
| | | | - Cori E Fain
- Mayo Clinic Graduate School of Biomedical Sciences, Rochester, MN 55905.,Mayo Clinic Department of Immunology, Rochester, MN 55905
| | - Roman H Khadka
- Mayo Clinic Graduate School of Biomedical Sciences, Rochester, MN 55905.,Mayo Clinic Department of Immunology, Rochester, MN 55905
| | - Emma N Goddery
- Mayo Clinic Graduate School of Biomedical Sciences, Rochester, MN 55905.,Mayo Clinic Department of Immunology, Rochester, MN 55905
| | - Lila T Yokanovich
- Mayo Clinic Graduate School of Biomedical Sciences, Rochester, MN 55905.,Mayo Clinic Department of Immunology, Rochester, MN 55905
| | - Megan L Settell
- Mayo Clinic Graduate School of Biomedical Sciences, Rochester, MN 55905
| | | | - Fang Jin
- Mayo Clinic Department of Immunology, Rochester, MN 55905
| | | | - Larry R Pease
- Mayo Clinic Department of Immunology, Rochester, MN 55905.,Mayo Clinic Department of Biochemistry, Rochester, MN 55905
| | - Aaron J Johnson
- Mayo Clinic Department of Immunology, Rochester, MN 55905; .,Mayo Clinic Department of Molecular Medicine, Rochester, MN 55905; and.,Mayo Clinic Department of Neurology, Rochester, MN 55905
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24
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Lebel MÈ, Coutelier M, Galipeau M, Kleinman CL, Moon JJ, Melichar HJ. Differential expression of tissue-restricted antigens among mTEC is associated with distinct autoreactive T cell fates. Nat Commun 2020; 11:3734. [PMID: 32709894 PMCID: PMC7381629 DOI: 10.1038/s41467-020-17544-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Accepted: 07/07/2020] [Indexed: 12/12/2022] Open
Abstract
Medullary thymic epithelial cells (mTEC) contribute to the development of T cell tolerance by expressing and presenting tissue-restricted antigens (TRA), so that developing T cells can assess the self-reactivity of their antigen receptors prior to leaving the thymus. mTEC are a heterogeneous population of cells that differentially express TRA. Whether mTEC subsets induce distinct autoreactive T cell fates remains unclear. Here, we establish bacterial artificial chromosome (BAC)-transgenic mouse lines with biased mTEClo or mTEChi expression of model antigens. The transgenic lines support negative selection of antigen-specific thymocytes depending on antigen dose. However, model antigen expression predominantly by mTEClo supports TCRαβ+ CD8αα intraepithelial lymphocyte development; meanwhile, mTEChi-restricted expression preferentially induces Treg differentiation of antigen-specific cells in these models to impact control of infectious agents and tumor growth. In summary, our data suggest that mTEC subsets may have a function in directing distinct mechanisms of T cell tolerance.
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Affiliation(s)
- Marie-Ève Lebel
- Maisonneuve-Rosemont Hospital Research Center, 5415 Boulevard de l'Assomption, Montreal, QC, H1T 2M4, Canada
- Département de microbiologie, infectiologie et immunologie, Université de Montréal, C.P. 6128, succ. Centre-ville, Montreal, QC, H3C 3J7, Canada
| | - Marie Coutelier
- The Lady Davis Institute for Medical Research, Jewish General Hospital, 3999 Côte Ste-Catherine Road Room E-542, Montreal, QC, H3T 1E2, Canada
- Department of Human Genetics, McGill University, Rm W-315, Strathcona Anatomy & Dentistry Building 3640 rue University, Montreal, QC, H3A 0C7, Canada
| | - Maria Galipeau
- Maisonneuve-Rosemont Hospital Research Center, 5415 Boulevard de l'Assomption, Montreal, QC, H1T 2M4, Canada
| | - Claudia L Kleinman
- The Lady Davis Institute for Medical Research, Jewish General Hospital, 3999 Côte Ste-Catherine Road Room E-542, Montreal, QC, H3T 1E2, Canada
- Department of Human Genetics, McGill University, Rm W-315, Strathcona Anatomy & Dentistry Building 3640 rue University, Montreal, QC, H3A 0C7, Canada
| | - James J Moon
- Center for Immunology and Inflammatory Diseases and Division of Pulmonary and Critical Care Medicine, Massachusetts General Hospital and Harvard Medical School, 149 13th Street, Charlestown, MA, 02129, USA
| | - Heather J Melichar
- Maisonneuve-Rosemont Hospital Research Center, 5415 Boulevard de l'Assomption, Montreal, QC, H1T 2M4, Canada.
- Département de médecine, Université de Montréal, C.P. 6128, succ. Centre-ville, Montreal, QC, H3C 3J7, Canada.
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25
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Eshima K, Misawa K, Ohashi C, Noma H, Iwabuchi K. NF-κB-inducing kinase contributes to normal development of cortical thymic epithelial cells: its possible role in shaping a proper T-cell repertoire. Immunology 2020; 160:198-208. [PMID: 32145062 PMCID: PMC7218659 DOI: 10.1111/imm.13186] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 03/02/2020] [Accepted: 03/03/2020] [Indexed: 01/13/2023] Open
Abstract
Nuclear factor (NF)-κB-inducing kinase (NIK) is known to be a critical regulator of multiple aspects of the immune response. Although the role of NIK in the development of medullary thymic epithelial cells (mTECs) has been well documented, the impact of NIK on the differentiation and function of cortical thymic epithelial cells (cTECs) remains ambiguous. To investigate the possible involvement of NIK in cTEC differentiation, we have compared the gene expression and function of cTECs from a NIK-mutant mouse, alymphoplasia (aly/aly) with those of cTECs from wild-type (WT) mice. Flow cytometric analyses revealed that expression levels of MHC class II, but not MHC class I or other TEC markers, were higher in aly/aly cells than in WT cells. Notably, the proportion of MHC class IIhi+ cTECs was elevated in aly/aly mice. We also demonstrated that expression of Ccl5 mRNA in the MHC class IIhi+ subset of aly/aly cTECs was decreased compared with that in WT cells, implying an abnormal pattern of gene expression in aly/aly cTECs. Analyses of bone marrow chimera using aly/aly or aly/+ mice as hosts suggested that Vβ usage and CD5 expression on WT T-cells were altered when they matured in aly/aly thymi. These results collectively indicate that NIK may be involved in controlling the function of cTEC in selecting a proper T-cell repertoire.
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Affiliation(s)
- Koji Eshima
- Department of ImmunologyKitasato University School of MedicineKanagawaJapan
| | - Kana Misawa
- Department of ImmunologyKitasato University School of MedicineKanagawaJapan
| | - Chihiro Ohashi
- Department of ImmunologyKitasato University School of MedicineKanagawaJapan
| | - Haruka Noma
- Department of ImmunologyKitasato University School of MedicineKanagawaJapan
| | - Kazuya Iwabuchi
- Department of ImmunologyKitasato University School of MedicineKanagawaJapan
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26
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Restricted Expression of the Thymoproteasome Is Required for Thymic Selection and Peripheral Homeostasis of CD8 + T Cells. Cell Rep 2020; 26:639-651.e2. [PMID: 30650357 DOI: 10.1016/j.celrep.2018.12.078] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Revised: 10/10/2018] [Accepted: 12/17/2018] [Indexed: 11/21/2022] Open
Abstract
The thymoproteasome subunit β5t is specifically expressed in cortical thymic epithelial cells (TECs) and generates unique peptides to support positive selection. In this study, using a mouse model ubiquitously expressing β5t, we showed that aberrant expression of self-peptides generated by β5t affects CD8+ T cell homeostasis, including thymic selection and maintenance of the peripheral naive pool of CD8+ T cells. In mice in which β5t was expressed both in cortical and medullary TECs, the abundance of CD8+ lineage thymocytes was reduced, and extra-thymic expression of β5t caused accumulation of CD8+ T cells with the memory or exhausted phenotype and induced autoreactive T cell responses. We found that thymoproteasomes are essential for positive selection but that the subsequent change in peptide repertoire in the medulla is also crucial for thymic selection and that β5t-derived peptide must be confined to the thymus to avoid autoimmunity in peripheral tissues.
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27
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Brown MA, Su MA. An Inconvenient Variable: Sex Hormones and Their Impact on T Cell Responses. THE JOURNAL OF IMMUNOLOGY 2020; 202:1927-1933. [PMID: 30885988 DOI: 10.4049/jimmunol.1801403] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Accepted: 12/05/2018] [Indexed: 12/15/2022]
Abstract
Epidemiologic data demonstrate sex differences in autoimmune diseases, immune responses against infection, and antitumor immunity, and accumulating evidence suggests a major role for sex hormones in mediating these differences. In this study, we review recent advances in understanding how sex hormones regulate T cell responses to alter susceptibility to autoimmunity. Although sex hormones can directly alter gene transcriptional programs of T cells, we focus in this study on how sex hormones alter T cell development and function through their effects on thymic stromal cells and innate cell types. In addition to contributing to our understanding of sex differences, these findings also have implications for the therapeutic use of sex hormones and sex hormone modulators, which are now being prescribed to increasing numbers of patients for a wide variety of indications.
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Affiliation(s)
- Melissa A Brown
- Department of Microbiology and Immunology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611
| | - Maureen A Su
- Department of Microbiology, Immunology and Molecular Genetics, David Geffen School of Medicine, College of Life Sciences, University of California at Los Angeles, Los Angeles, CA 90095; and .,Department of Pediatrics, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA 90095
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28
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Kurd NS, Lutes LK, Yoon J, Chan SW, Dzhagalov IL, Hoover AR, Robey EA. A role for phagocytosis in inducing cell death during thymocyte negative selection. eLife 2019; 8:48097. [PMID: 31868579 PMCID: PMC6957271 DOI: 10.7554/elife.48097] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Accepted: 12/21/2019] [Indexed: 12/11/2022] Open
Abstract
Autoreactive thymocytes are eliminated during negative selection in the thymus, a process important for establishing self-tolerance. Thymic phagocytes serve to remove dead thymocytes, but whether they play additional roles during negative selection remains unclear. Here, using a murine thymic slice model in which thymocytes undergo negative selection in situ, we demonstrate that phagocytosis promotes negative selection, and provide evidence for the escape of autoreactive CD8 T cells to the periphery when phagocytosis in the thymus is impaired. We also show that negative selection is more efficient when the phagocyte also presents the negative selecting peptide. Our findings support a model for negative selection in which the death process initiated following strong TCR signaling is facilitated by phagocytosis. Thus, the phagocytic capability of cells that present self-peptides is a key determinant of thymocyte fate.
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Affiliation(s)
- Nadia S Kurd
- Division of Immunology and Pathogenesis, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Lydia K Lutes
- Division of Immunology and Pathogenesis, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Jaewon Yoon
- Division of Immunology and Pathogenesis, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Shiao Wei Chan
- Division of Immunology and Pathogenesis, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Ivan L Dzhagalov
- Division of Immunology and Pathogenesis, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Ashley R Hoover
- Division of Immunology and Pathogenesis, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Ellen A Robey
- Division of Immunology and Pathogenesis, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
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29
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Transforming Growth Factor-beta signaling in αβ thymocytes promotes negative selection. Nat Commun 2019; 10:5690. [PMID: 31857584 PMCID: PMC6923358 DOI: 10.1038/s41467-019-13456-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Accepted: 11/06/2019] [Indexed: 01/04/2023] Open
Abstract
In the thymus, the T lymphocyte repertoire is purged of a substantial portion of highly self-reactive cells. This negative selection process relies on the strength of TCR-signaling in response to self-peptide-MHC complexes, both in the cortex and medulla regions. However, whether cytokine-signaling contributes to negative selection remains unclear. Here, we report that, in the absence of Transforming Growth Factor beta (TGF-β) signaling in thymocytes, negative selection is significantly impaired. Highly autoreactive thymocytes first escape cortical negative selection and acquire a Th1-like-phenotype. They express high levels of CXCR3, aberrantly accumulate at the cortico-medullary junction and subsequently fail to sustain AIRE expression in the medulla, escaping medullary negative selection. Highly autoreactive thymocytes undergo an atypical maturation program, substantially accumulate in the periphery and induce multiple organ-autoimmune-lesions. Thus, these findings reveal TGF-β in thymocytes as crucial for negative selection with implications for understanding T cell self-tolerance mechanisms.
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30
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Insights into Thymus Development and Viral Thymic Infections. Viruses 2019; 11:v11090836. [PMID: 31505755 PMCID: PMC6784209 DOI: 10.3390/v11090836] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 09/03/2019] [Accepted: 09/06/2019] [Indexed: 12/16/2022] Open
Abstract
T-cell development in the thymus is a complex and highly regulated process, involving a wide variety of cells and molecules which orchestrate thymocyte maturation into either CD4+ or CD8+ single-positive (SP) T cells. Here, we briefly review the process regulating T-cell differentiation, which includes the latest advances in this field. In particular, we highlight how, starting from a pool of hematopoietic stem cells in the bone marrow, the sequential action of transcriptional factors and cytokines dictates the proliferation, restriction of lineage potential, T-cell antigen receptors (TCR) gene rearrangements, and selection events on the T-cell progenitors, ultimately leading to the generation of mature T cells. Moreover, this review discusses paradigmatic examples of viral infections affecting the thymus that, by inducing functional changes within this lymphoid gland, consequently influence the behavior of peripheral mature T-lymphocytes.
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31
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McDonald BD, Jabri B, Bendelac A. Diverse developmental pathways of intestinal intraepithelial lymphocytes. Nat Rev Immunol 2019; 18:514-525. [PMID: 29717233 DOI: 10.1038/s41577-018-0013-7] [Citation(s) in RCA: 114] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The intestinal epithelial barrier is patrolled by resident intraepithelial lymphocytes (IELs) that are involved in host defence against pathogens, wound repair and homeostatic interactions with the epithelium, microbiota and nutrients. Intestinal IELs are one of the largest populations of lymphocytes in the body and comprise several distinct subsets, the identity and lineage relationships of which have long remained elusive. Here, we review advances in unravelling the complexity of intestinal IEL populations, which comprise conventional αβ T cell receptor (TCRαβ)+ subsets, unconventional TCRαβ+ and TCRγδ+ subsets, group 1 innate lymphoid cells (ILC1s) and ILC1-like cells. Although these intestinal IEL lineages have partially overlapping effector programmes and recognition properties, they have strikingly different developmental pathways. We suggest that evolutionary pressure has driven the recurrent generation of cytolytic effector lymphocytes to protect the intestinal epithelial layer, but they may also precipitate intestinal inflammatory disorders, such as coeliac disease.
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Affiliation(s)
- Benjamin D McDonald
- Committee on Immunology, University of Chicago, Chicago, IL, USA.,Department of Pathology, University of Chicago, Chicago, IL, USA.,Department of Medicine, University of Chicago, Chicago, IL, USA
| | - Bana Jabri
- Committee on Immunology, University of Chicago, Chicago, IL, USA.,Department of Pathology, University of Chicago, Chicago, IL, USA.,Department of Medicine, University of Chicago, Chicago, IL, USA
| | - Albert Bendelac
- Committee on Immunology, University of Chicago, Chicago, IL, USA. .,Department of Pathology, University of Chicago, Chicago, IL, USA.
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32
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Luan R, Liang Z, Zhang Q, Sun L, Zhao Y. Molecular regulatory networks of thymic epithelial cell differentiation. Differentiation 2019; 107:42-49. [PMID: 31238242 DOI: 10.1016/j.diff.2019.06.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 06/04/2019] [Accepted: 06/12/2019] [Indexed: 01/15/2023]
Abstract
Functional mature T cells are generated in the thymus. Thymic epithelial cells (TECs) provide the essential microenvironment for T cell development and maturation. According to their function and localization, TECs are roughly divided into cortical TECs (cTECs) and medullary TECs (mTECs), which are responsible for positive and negative selection, respectively. This review summarizes the current understanding of TEC biology, the identification of fetal and adult bipotent TEC progenitors, and the signaling pathways that control the development and maturation of TECs. The understanding of the ontogeny, differentiation, maturation and function of cTECs lags behind that of mTECs. Better understanding TEC biology will provide clues about TEC development and the applications of thymus engineering.
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Affiliation(s)
- Rong Luan
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Zhanfeng Liang
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Qian Zhang
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China
| | - Liguang Sun
- Institute of Translational Medicine, The First Hospital, Jilin University, Changchun, Jilin, China.
| | - Yong Zhao
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China; Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing, China.
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33
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Deletion of self-reactive CCR7- thymocytes in the absence of MHC expression on thymic epithelial cells. Cell Death Differ 2019; 26:2727-2739. [PMID: 31019259 DOI: 10.1038/s41418-019-0331-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Revised: 03/18/2019] [Accepted: 04/05/2019] [Indexed: 12/11/2022] Open
Abstract
The selection of αβ T cells in the thymus is punctuated by checkpoints at which thymocytes differentiate or undergo apoptosis. Wave 1 deletion is defined as apoptosis within nascent αβ T-cell antigen receptor (TCR)-signalled thymocytes that lack CCR7 expression. The antigen-presenting cell (APC) types that mediate wave 1 deletion are unclear. To measure wave 1 deletion, we compared the frequencies of TCRβ + CD5 + Helios + CCR7- cells in nascent thymocyte cohorts in mice with normal or defective apoptosis. This thymocyte population is small in mice lacking major histocompatibility complex (MHC) expression. The scale of wave 1 deletion was increased by transgenic expression of the self-reactive Yae62 TCRβ chain, was almost halved when haemopoietic APCs lacked MHC expression and, surprisingly, was unchanged when epithelial cells lacked MHC expression. These findings demonstrate efficiency, and some redundancy, in the APC types that mediate wave 1 deletion in the normal mouse thymus.
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34
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Breed ER, Watanabe M, Hogquist KA. Measuring Thymic Clonal Deletion at the Population Level. THE JOURNAL OF IMMUNOLOGY 2019; 202:3226-3233. [PMID: 31010850 DOI: 10.4049/jimmunol.1900191] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Accepted: 03/25/2019] [Indexed: 12/18/2022]
Abstract
Clonal deletion of T cells specific for self-antigens in the thymus has been widely studied, primarily by approaches that focus on a single receptor (using TCR transgenes) or a single specificity (using peptide-MHC tetramers). However, less is known about clonal deletion at the population level. In this article, we report an assay that measures cleaved caspase 3 to define clonal deletion at the population level. This assay distinguishes clonal deletion from apoptotic events caused by neglect and approximates the anatomic site of deletion using CCR7. This approach showed that 78% of clonal deletion events occur in the cortex in mice. Medullary deletion events were detected at both the semimature and mature stages, although mature events were associated with failed regulatory T cell induction. Using this assay, we showed that bone marrow-derived APC drive approximately half of deletion events at both stages. We also found that both cortical and medullary deletion rely heavily on CD28 costimulation. These findings demonstrate a useful strategy for studying clonal deletion within the polyclonal repertoire.
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Affiliation(s)
- Elise R Breed
- Department of Laboratory Medicine and Pathology, Center for Immunology, University of Minnesota Medical School, Minneapolis, MN 55455; and
| | - Masashi Watanabe
- Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892
| | - Kristin A Hogquist
- Department of Laboratory Medicine and Pathology, Center for Immunology, University of Minnesota Medical School, Minneapolis, MN 55455; and
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35
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Santamaria J, Darrigues J, van Meerwijk JP, Romagnoli P. Antigen-presenting cells and T-lymphocytes homing to the thymus shape T cell development. Immunol Lett 2018; 204:9-15. [DOI: 10.1016/j.imlet.2018.10.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 10/01/2018] [Accepted: 10/07/2018] [Indexed: 11/28/2022]
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36
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Wirasinha RC, Singh M, Archer SK, Chan A, Harrison PF, Goodnow CC, Daley SR. αβ T-cell receptors with a central CDR3 cysteine are enriched in CD8αα intraepithelial lymphocytes and their thymic precursors. Immunol Cell Biol 2018; 96:553-561. [PMID: 29726044 DOI: 10.1111/imcb.12047] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Revised: 03/09/2018] [Accepted: 03/23/2018] [Indexed: 01/04/2023]
Abstract
The thymus plays a crucial role in immune tolerance by exposing developing T cells (thymocytes) to a myriad of self-antigens. Strong T-cell receptor (TCR) engagement induces tolerance in self-reactive thymocytes by stimulating apoptosis or selection into specialized T-cell lineages, including intestinal TCRαβ+ CD8αα+ intraepithelial lymphocytes (IEL). TCR-intrinsic amino acid motifs that can be used to predict whether a TCR will be strongly self-reactive remain elusive. Here, a novel TCR sequence alignment approach revealed that T-cell lineages in C57BL/6 mice had divergent usage of cysteine within two positions of the amino acid at the apex of the complementarity-determining region 3 (CDR3) of the TCRα or TCRβ chain. Compared to pre-selection thymocytes, central CDR3 cysteine usage was increased in IEL and Type A IEL precursors (IELp) and markedly decreased in Foxp3+ regulatory T cells (T-reg) and naïve T cells. These findings reveal a TCR-intrinsic motif that distinguishes Type A IELp and IEL from T-reg and naïve T cells.
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Affiliation(s)
- Rushika C Wirasinha
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Melbourne, VIC, 3800, Australia
| | - Mandeep Singh
- Immunology Division, Garvan Institute of Medical Research, Sydney, NSW, 2010, Australia
| | - Stuart K Archer
- Monash Bioinformatics Platform, Monash University, Melbourne, VIC, 3800, Australia
| | - Anna Chan
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Melbourne, VIC, 3800, Australia
| | - Paul F Harrison
- Monash Bioinformatics Platform, Monash University, Melbourne, VIC, 3800, Australia
| | - Christopher C Goodnow
- Immunology Division, Garvan Institute of Medical Research, Sydney, NSW, 2010, Australia.,St Vincent's Clinical School, University of New South Wales, Sydney, NSW, 2052, Australia
| | - Stephen R Daley
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Melbourne, VIC, 3800, Australia
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37
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Apert C, Romagnoli P, van Meerwijk JPM. IL-2 and IL-15 dependent thymic development of Foxp3-expressing regulatory T lymphocytes. Protein Cell 2018; 9:322-332. [PMID: 28540653 PMCID: PMC5876181 DOI: 10.1007/s13238-017-0425-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Accepted: 05/04/2017] [Indexed: 12/15/2022] Open
Abstract
Immunosuppressive regulatory T lymphocytes (Treg) expressing the transcription factor Foxp3 play a vital role in the maintenance of tolerance of the immune-system to self and innocuous non-self. Most Treg that are critical for the maintenance of tolerance to self, develop as an independent T-cell lineage from common T cell precursors in the thymus. In this organ, their differentiation requires signals from the T cell receptor for antigen, from co-stimulatory molecules, as well as from cytokine-receptors. Here we focus on the cytokines implicated in thymic development of Treg, with a particular emphasis on the roles of interleukin-2 (IL-2) and IL-15. The more recently appreciated involvement of TGF-β in thymic Treg development is also briefly discussed. Finally, we discuss how cytokine-dependence of Treg development allows for temporal, quantitative, and potentially qualitative modulation of this process.
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Affiliation(s)
- Cécile Apert
- CPTP, Université de Toulouse, CNRS, Inserm, UPS, Toulouse, France
| | - Paola Romagnoli
- CPTP, Université de Toulouse, CNRS, Inserm, UPS, Toulouse, France.
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38
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Lopes N, Charaix J, Cédile O, Sergé A, Irla M. Lymphotoxin α fine-tunes T cell clonal deletion by regulating thymic entry of antigen-presenting cells. Nat Commun 2018; 9:1262. [PMID: 29593265 PMCID: PMC5872006 DOI: 10.1038/s41467-018-03619-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Accepted: 02/28/2018] [Indexed: 12/31/2022] Open
Abstract
Medullary thymic epithelial cells (mTEC) purge the T cell repertoire of autoreactive thymocytes. Although dendritic cells (DC) reinforce this process by transporting innocuous peripheral self-antigens, the mechanisms that control their thymic entry remain unclear. Here we show that mTEC-CD4+ thymocyte crosstalk regulates the thymus homing of SHPS-1+ conventional DCs (cDC), plasmacytoid DCs (pDC) and macrophages. This homing process is controlled by lymphotoxin α (LTα), which negatively regulates CCL2, CCL8 and CCL12 chemokines in mTECs. Consequently, Ltα-deficient mice have increased expression of these chemokines that correlates with augmented classical NF-κB subunits and increased thymic recruitment of cDCs, pDCs and macrophages. This enhanced migration depends mainly on the chemokine receptor CCR2, and increases thymic clonal deletion. Altogether, this study identifies a fine-tuning mechanism of T cell repertoire selection and paves the way for therapeutic interventions to treat autoimmune disorders.
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Affiliation(s)
- Noëlla Lopes
- Centre d'Immunologie de Marseille-Luminy, INSERM U1104, CNRS UMR7280, Aix-Marseille Université UM2, Marseille, 13288 cedex 09, France
| | - Jonathan Charaix
- Centre d'Immunologie de Marseille-Luminy, INSERM U1104, CNRS UMR7280, Aix-Marseille Université UM2, Marseille, 13288 cedex 09, France
| | - Oriane Cédile
- Institute of Molecular Medicine, Department of Neurobiology Research, University of Southern Denmark, J.B. Winsløwsvej 25, 5000, Odense C, Denmark
| | - Arnauld Sergé
- Centre de Recherche en Cancérologie de Marseille, Institut Paoli-Calmettes, INSERM U1068, CNRS UMR7258, Aix-Marseille Université UM105, 13273 cedex 09, Marseille, France
| | - Magali Irla
- Centre d'Immunologie de Marseille-Luminy, INSERM U1104, CNRS UMR7280, Aix-Marseille Université UM2, Marseille, 13288 cedex 09, France.
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39
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Escape from thymic deletion and anti-leukemic effects of T cells specific for hematopoietic cell-restricted antigen. Nat Commun 2018; 9:225. [PMID: 29335408 PMCID: PMC5768767 DOI: 10.1038/s41467-017-02665-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Accepted: 12/18/2017] [Indexed: 12/17/2022] Open
Abstract
Whether hematopoietic cell-restricted distribution of antigens affects the degree of thymic negative selection has not been investigated in detail. Here, we show that T cells specific for hematopoietic cell-restricted antigens (HRA) are not completely deleted in the thymus, using the mouse minor histocompatibility antigen H60, the expression of which is restricted to hematopoietic cells. As a result, low avidity T cells escape from thymic deletion. This incomplete thymic deletion occurs to the T cells developing de novo in the thymus of H60-positive recipients in H60-mismatched bone marrow transplantation (BMT). H60-specific thymic deletion escapee CD8+ T cells exhibit effector differentiation potentials in the periphery and contribute to graft-versus-leukemia effects in the recipients of H60-mismatched BMT, regressing H60+ hematological tumors. These results provide information essential for understanding thymic negative selection and developing a strategy to treat hematological tumors.
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40
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Lancaster JN, Li Y, Ehrlich LIR. Chemokine-Mediated Choreography of Thymocyte Development and Selection. Trends Immunol 2017; 39:86-98. [PMID: 29162323 DOI: 10.1016/j.it.2017.10.007] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Revised: 10/19/2017] [Accepted: 10/27/2017] [Indexed: 12/30/2022]
Abstract
As they differentiate, thymocytes encounter spatially restricted cues critical for differentiation and selection of a functional, self-tolerant T cell repertoire. Sequential migration of developing T cells through distinct thymic microenvironments is enforced by the ordered expression of chemokine receptors. Herein, we provide an updated perspective on T cell differentiation through the lens of recent advances that illuminate the dynamics of chemokine-driven thymocyte migration, localization, and interactions with stromal cells. We consider these findings in the context of earlier groundwork exploring the contribution of chemokines to T cell development, recent advances regarding the specificity of chemokine signaling, and novel techniques for evaluating the T cell repertoire. We suggest future research should amalgamate visualization of localized cellular interactions with downstream molecular signals.
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Affiliation(s)
- Jessica N Lancaster
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA
| | - Yu Li
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA
| | - Lauren I R Ehrlich
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA.
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41
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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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42
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Breed ER, Lee ST, Hogquist KA. Directing T cell fate: How thymic antigen presenting cells coordinate thymocyte selection. Semin Cell Dev Biol 2017; 84:2-10. [PMID: 28800929 DOI: 10.1016/j.semcdb.2017.07.045] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 06/30/2017] [Accepted: 07/30/2017] [Indexed: 01/02/2023]
Abstract
The development of a self-tolerant and effective T cell receptor repertoire is dependent on interactions coordinated by various antigen presenting cells (APC) within the thymus. T cell receptor-self-peptide-MHC interactions are essential for determining T cell fate, however different cytokine and co-stimulatory signals provided by the diverse APCs within the thymus are also critical. Here, we outline the different localization and functional capabilities of thymic APCs. We also discuss how these distinct APCs work collectively to facilitate the establishment of a diverse T cell receptor repertoire that is tolerant to an array of different self-antigens.
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Affiliation(s)
- Elise R Breed
- The Center for Immunology, Department of Laboratory Medicine & Pathology, University of Minnesota, Minneapolis, MN, USA
| | - S Thera Lee
- The Center for Immunology, Department of Laboratory Medicine & Pathology, University of Minnesota, Minneapolis, MN, USA
| | - Kristin A Hogquist
- The Center for Immunology, Department of Laboratory Medicine & Pathology, University of Minnesota, Minneapolis, MN, USA.
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43
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Golec DP, Hoeppli RE, Henao Caviedes LM, McCann J, Levings MK, Baldwin TA. Thymic progenitors of TCRαβ + CD8αα intestinal intraepithelial lymphocytes require RasGRP1 for development. J Exp Med 2017; 214:2421-2435. [PMID: 28652304 PMCID: PMC5551581 DOI: 10.1084/jem.20170844] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Revised: 06/16/2017] [Accepted: 06/20/2017] [Indexed: 12/23/2022] Open
Abstract
Golec et al. show that RasGRP1, a critical Ras activator in thymocytes, is required for TCRαβ+CD8αα IEL development by regulating the survival of a heterogeneous population of thymic progenitors that receive a strong TCR signal. Therefore, RasGRP1 is necessary for thymic selection events stemming from strong or weak TCR signals. Strong T cell receptor (TCR) signaling largely induces cell death during thymocyte development, whereas weak TCR signals induce positive selection. However, some T cell lineages require strong TCR signals for differentiation through a process termed agonist selection. The signaling relationships that underlie these three fates are unknown. RasGRP1 is a Ras activator required to transmit weak TCR signals leading to positive selection. Here, we report that, despite being dispensable for thymocyte clonal deletion, RasGRP1 is critical for agonist selection of TCRαβ+CD8αα intraepithelial lymphocyte (IEL) progenitors (IELps), even though both outcomes require strong TCR signaling. Bim deficiency rescued IELp development in RasGRP1−/− mice, suggesting that RasGRP1 functions to promote survival during IELp generation. Additionally, expression of CD122 and the adhesion molecules α4β7 and CD103 define distinct IELp subsets with differing abilities to generate TCRαβ+CD8αα IEL in vivo. These findings demonstrate that RasGRP1-dependent signaling underpins thymic selection processes induced by both weak and strong TCR signals and is differentially required for fate decisions derived from a strong TCR stimulus.
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Affiliation(s)
- Dominic P Golec
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, AB, Canada
| | - Romy E Hoeppli
- Department of Surgery, University of British Columbia, Vancouver, BC, Canada
| | - Laura M Henao Caviedes
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, AB, Canada
| | - Jillian McCann
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, AB, Canada
| | - Megan K Levings
- Department of Surgery, University of British Columbia, Vancouver, BC, Canada
| | - Troy A Baldwin
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, AB, Canada
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44
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A rheostat tuning thymic selection. Nat Immunol 2017. [PMID: 28632719 DOI: 10.1038/ni.3778] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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45
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Hu DY, Wirasinha RC, Goodnow CC, Daley SR. IL-2 prevents deletion of developing T-regulatory cells in the thymus. Cell Death Differ 2017; 24:1007-1016. [PMID: 28362433 DOI: 10.1038/cdd.2017.38] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Revised: 02/21/2017] [Accepted: 02/27/2017] [Indexed: 12/12/2022] Open
Abstract
In the thymus, strongly self-reactive T cells may undergo apoptotic deletion or differentiate into Foxp3+ T-regulatory (T-reg) cells. Mechanisms that partition T cells into these two fates are unclear. Here, we show that IL-2 signalling is required to prevent deletion of CD4+ CD8- CCR7+ Helios+ thymocytes poised to upregulate Foxp3. The deletion prevented by IL-2 signalling is Foxp3 independent and occurs later in thymocyte development than the deletion that is prevented by Card11 signalling. Our results distinguish two bottlenecks at which strongly self-reactive thymocytes undergo deletion or progress to the next stage of T-reg differentiation; Card11 regulates the first bottleneck and IL-2 regulates the second.
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Affiliation(s)
- Daniel Y Hu
- Immunology Department, The John Curtin School of Medical Research, The Australian National University, Canberra 0200, Australia
| | - Rushika C Wirasinha
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Melbourne, VIC 3800, Australia
| | - Christopher C Goodnow
- Immunology Department, The John Curtin School of Medical Research, The Australian National University, Canberra 0200, Australia.,Immunology Division, Garvan Institute of Medical Research, Sydney, NSW 2010, Australia
| | - Stephen R Daley
- Immunology Department, The John Curtin School of Medical Research, The Australian National University, Canberra 0200, Australia.,Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Melbourne, VIC 3800, Australia
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46
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Daley SR, Teh C, Hu DY, Strasser A, Gray DH. Cell death and thymic tolerance. Immunol Rev 2017; 277:9-20. [DOI: 10.1111/imr.12532] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Stephen R. Daley
- Infection and Immunity Program; Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology; Monash University; Melbourne VIC Australia
| | - Charis Teh
- The Walter and Eliza Hall Institute of Medical Research; Melbourne VIC Australia
- Department of Medical Biology; The University of Melbourne; Parkville VIC Australia
| | | | - Andreas Strasser
- The Walter and Eliza Hall Institute of Medical Research; Melbourne VIC Australia
- Department of Medical Biology; The University of Melbourne; Parkville VIC Australia
| | - Daniel H.D. Gray
- The Walter and Eliza Hall Institute of Medical Research; Melbourne VIC Australia
- Department of Medical Biology; The University of Melbourne; Parkville VIC Australia
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47
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Abstract
Intrathymic T cell development is a complex process that depends upon continuous guidance from thymus stromal cell microenvironments. The thymic epithelium within the thymic stroma comprises highly specialized cells with a high degree of anatomic, phenotypic, and functional heterogeneity. These properties are collectively required to bias thymocyte development toward production of self-tolerant and functionally competent T cells. The importance of thymic epithelial cells (TECs) is evidenced by clear links between their dysfunction and multiple diseases where autoimmunity and immunodeficiency are major components. Consequently, TECs are an attractive target for cell therapies to restore effective immune system function. The pathways and molecular regulators that control TEC development are becoming clearer, as are their influences on particular stages of T cell development. Here, we review both historical and the most recent advances in our understanding of the cellular and molecular mechanisms controlling TEC development, function, dysfunction, and regeneration.
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Affiliation(s)
- Jakub Abramson
- Department of Immunology, Weizmann Institute of Science, Rehovot 76100, Israel;
| | - Graham Anderson
- MRC Centre for Immune Regulation, Institute for Immunology and Immunotherapy, University of Birmingham, Birmingham B15 2TT, United Kingdom;
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48
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Abstract
The ability of T cells to respond to a wide array of foreign antigens while avoiding reactivity to self is largely determined by cellular selection of developing T cells in the thymus. While a great deal is known about the cell types and molecules involved in T-cell selection in the thymus, our understanding of the spatial and temporal aspects of this process remain relatively poorly understood. Thymocytes are highly motile within the thymus and travel between specialized microenvironments at different phases of their development while interacting with distinct sets of self-peptides and peptide presenting cells. A knowledge of when, where, and how thymocytes encounter self-peptide MHC ligands at different stages of thymic development is key to understanding T-cell selection. In the past several years, our laboratory has investigated this topic using two-photon time-lapse microscopy to directly visualize thymocyte migration and signaling events, together with a living thymic slice preparation to provide a synchronized experimental model of T-cell selection in situ. Here, we discuss recent advances in our understanding of the temporal and spatial aspects of T-cell selection, highlighting our own work, and placing them in the context of work from other groups.
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Affiliation(s)
- Nadia Kurd
- Division of Immunology and Pathogenesis, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, 94720, USA
| | - Ellen A Robey
- Division of Immunology and Pathogenesis, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, 94720, USA
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49
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Li KP, Fähnrich A, Roy E, Cuda CM, Grimes HL, Perlman HR, Kalies K, Hildeman DA. Temporal Expression of Bim Limits the Development of Agonist-Selected Thymocytes and Skews Their TCRβ Repertoire. THE JOURNAL OF IMMUNOLOGY 2016; 198:257-269. [PMID: 27852740 DOI: 10.4049/jimmunol.1601200] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Accepted: 10/25/2016] [Indexed: 12/11/2022]
Abstract
CD8αα TCRαβ+ intestinal intraepithelial lymphocytes play a critical role in promoting intestinal homeostasis, although mechanisms controlling their development and peripheral homeostasis remain unclear. In this study, we examined the spatiotemporal role of Bim in the thymic selection of CD8αα precursors and the fate of these cells in the periphery. We found that T cell-specific expression of Bim during early/cortical, but not late/medullary, thymic development controls the agonist selection of CD8αα precursors and limits their private TCRβ repertoire. During this process, agonist-selected double-positive cells lose CD4/8 coreceptor expression and masquerade as double-negative (DN) TCRαβhi thymocytes. Although these DN thymocytes fail to re-express coreceptors after OP9-DL1 culture, they eventually mature and accumulate in the spleen where TCR and IL-15/STAT5 signaling promotes their conversion to CD8αα cells and their expression of gut-homing receptors. Adoptive transfer of splenic DN cells gives rise to CD8αα cells in the gut, establishing their precursor relationship in vivo. Interestingly, Bim does not restrict the IL-15-driven maturation of CD8αα cells that is critical for intestinal homeostasis. Thus, we found a temporal and tissue-specific role for Bim in limiting thymic agonist selection of CD8αα precursors and their TCRβ repertoire, but not in the maintenance of CD8αα intraepithelial lymphocytes in the intestine.
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Affiliation(s)
- Kun-Po Li
- Division of Immunobiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229.,Department of Pediatrics, University of Cincinnati, Cincinnati, OH 45257
| | - Anke Fähnrich
- Institute for Anatomy, University of Lübeck, 23538 Lübeck, Germany; and
| | - Eron Roy
- Division of Immunobiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229.,Department of Pediatrics, University of Cincinnati, Cincinnati, OH 45257
| | - Carla M Cuda
- Rheumatology Division, Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611
| | - H Leighton Grimes
- Division of Immunobiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229.,Department of Pediatrics, University of Cincinnati, Cincinnati, OH 45257
| | - Harris R Perlman
- Rheumatology Division, Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611
| | - Kathrin Kalies
- Institute for Anatomy, University of Lübeck, 23538 Lübeck, Germany; and
| | - David A Hildeman
- Division of Immunobiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229; .,Department of Pediatrics, University of Cincinnati, Cincinnati, OH 45257
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50
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Sood A, Dong M, Melichar HJ. Preparation and Applications of Organotypic Thymic Slice Cultures. J Vis Exp 2016. [PMID: 27585240 DOI: 10.3791/54355] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Thymic selection proceeds in a unique and highly organized thymic microenvironment resulting in the generation of a functional, self-tolerant T cell repertoire. In vitro models to study T lineage commitment and development have provided valuable insights into this process. However, these systems lack the complete three-dimensional thymic milieu necessary for T cell development and, therefore, are incomplete approximations of in vivo thymic selection. Some of the challenges related to modeling T cell development can be overcome by using in situ models that provide an intact thymic microenvironment that fully supports thymic selection of developing T cells. Thymic slice organotypic cultures complement existing in situ techniques. Thymic slices preserve the integrity of the thymic cortical and medullary regions and provide a platform to study development of overlaid thymocytes of a defined developmental stage or of endogenous T cells within a mature thymic microenvironment. Given the ability to generate ~20 slices per mouse, thymic slices present a unique advantage in terms of scalability for high throughput experiments. Further, the relative ease in generating thymic slices and potential to overlay different thymic subsets or other cell populations from diverse genetic backgrounds enhances the versatility of this method. Here we describe a protocol for the preparation of thymic slices, isolation and overlay of thymocytes, and dissociation of thymic slices for flow cytometric analysis. This system can also be adapted to study non-conventional T cell development as well as visualize thymocyte migration, thymocyte-stromal cell interactions, and TCR signals associated with thymic selection by two-photon microscopy.
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Affiliation(s)
- Aditi Sood
- Centre de Recherche, Hôpital Maisonneuve-Rosemont; Department of Microbiology, Infectiology and Immunology, Université de Montréal
| | - Mengqi Dong
- Centre de Recherche, Hôpital Maisonneuve-Rosemont; Department of Microbiology, Infectiology and Immunology, Université de Montréal
| | - Heather J Melichar
- Centre de Recherche, Hôpital Maisonneuve-Rosemont; Department of Medicine, Université de Montréal;
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