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Anderson G, Cosway EJ, James KD, Ohigashi I, Takahama Y. Generation and repair of thymic epithelial cells. J Exp Med 2024; 221:e20230894. [PMID: 38980292 PMCID: PMC11232892 DOI: 10.1084/jem.20230894] [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: 02/02/2024] [Revised: 05/20/2024] [Accepted: 06/10/2024] [Indexed: 07/10/2024] Open
Abstract
In the vertebrate immune system, thymus stromal microenvironments support the generation of αβT cells from immature thymocytes. Thymic epithelial cells are of particular importance, and the generation of cortical and medullary epithelial lineages from progenitor stages controls the initiation and maintenance of thymus function. Here, we discuss the developmental pathways that regulate thymic epithelial cell diversity during both the embryonic and postnatal periods. We also examine how thymus microenvironments respond to injury, with particular focus on mechanisms that ensure regeneration of thymic epithelial cells for the restoration of thymus function.
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Affiliation(s)
- Graham Anderson
- Institute for Immunology and Immunotherapy, University of Birmingham , Birmingham, UK
| | - Emilie J Cosway
- Institute for Immunology and Immunotherapy, University of Birmingham , Birmingham, UK
| | - Kieran D James
- Institute for Immunology and Immunotherapy, University of Birmingham , Birmingham, UK
| | - 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, 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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