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Duah M, Li L, Shen J, Lan Q, Pan B, Xu K. Thymus Degeneration and Regeneration. Front Immunol 2021; 12:706244. [PMID: 34539637 PMCID: PMC8442952 DOI: 10.3389/fimmu.2021.706244] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Accepted: 08/16/2021] [Indexed: 01/08/2023] Open
Abstract
The immune system’s ability to resist the invasion of foreign pathogens and the tolerance to self-antigens are primarily centered on the efficient functions of the various subsets of T lymphocytes. As the primary organ of thymopoiesis, the thymus performs a crucial role in generating a self-tolerant but diverse repertoire of T cell receptors and peripheral T cell pool, with the capacity to recognize a wide variety of antigens and for the surveillance of malignancies. However, cells in the thymus are fragile and sensitive to changes in the external environment and acute insults such as infections, chemo- and radiation-therapy, resulting in thymic injury and degeneration. Though the thymus has the capacity to self-regenerate, it is often insufficient to reconstitute an intact thymic function. Thymic dysfunction leads to an increased risk of opportunistic infections, tumor relapse, autoimmunity, and adverse clinical outcome. Thus, exploiting the mechanism of thymic regeneration would provide new therapeutic options for these settings. This review summarizes the thymus’s development, factors causing thymic injury, and the strategies for improving thymus regeneration.
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Affiliation(s)
- Maxwell Duah
- Department of Hematology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou Medical University, Xuzhou, China.,Blood Diseases Institute, Xuzhou Medical University, Xuzhou, China
| | - Lingling Li
- Department of Hematology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou Medical University, Xuzhou, China.,Blood Diseases Institute, Xuzhou Medical University, Xuzhou, China
| | - Jingyi Shen
- Department of Hematology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou Medical University, Xuzhou, China.,Blood Diseases Institute, Xuzhou Medical University, Xuzhou, China
| | - Qiu Lan
- Department of Hematology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou Medical University, Xuzhou, China.,Blood Diseases Institute, Xuzhou Medical University, Xuzhou, China
| | - Bin Pan
- Department of Hematology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou Medical University, Xuzhou, China.,Blood Diseases Institute, Xuzhou Medical University, Xuzhou, China
| | - Kailin Xu
- Department of Hematology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou Medical University, Xuzhou, China.,Blood Diseases Institute, Xuzhou Medical University, Xuzhou, China
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Lustig A, Weeraratna AT, Wood WW, Teichberg D, Bertak D, Carter A, Poosala S, Firman J, Becker KG, Zonderman AB, Longo DL, Taub DD. Transcriptome analysis of age-, gender- and diet-associated changes in murine thymus. Cell Immunol 2007; 245:42-61. [PMID: 17499630 PMCID: PMC2271048 DOI: 10.1016/j.cellimm.2007.03.008] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2007] [Revised: 03/25/2007] [Accepted: 03/27/2007] [Indexed: 01/18/2023]
Abstract
The loss of thymic function with age may be due to diminished numbers of T-cell progenitors and the loss of critical mediators within the thymic microenvironment. To assess the molecular changes associated with this loss, we examined transcriptomes of progressively aging mouse thymi, of different sexes and on caloric-restricted (CR) vs. ad libitum (AL) diets. Genes involved in various biological and molecular processes including transcriptional regulators, stress response, inflammation and immune function significantly changed during thymic aging. These differences depended on variables such as sex and diet. Interestingly, many changes associated with thymic aging are either muted or almost completely reversed in mice on caloric-restricted diets. These studies provide valuable insight into the molecular mechanisms associated with thymic aging and emphasize the need to account for biological variables such as sex and diet when elucidating the genomic correlates that influence the molecular pathways responsible for thymic involution.
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Affiliation(s)
- Ana Lustig
- Laboratory of Immunology, National Institute on Aging-Intramural Research Program, National Institutes of Health, 5600 Nathan Shock Drive, Baltimore, MD 21224, USA
| | - Ashani T. Weeraratna
- Laboratory of Immunology, National Institute on Aging-Intramural Research Program, National Institutes of Health, 5600 Nathan Shock Drive, Baltimore, MD 21224, USA
| | - William W. Wood
- The Research Resources Branch, National Institute on Aging-Intramural Research Program, National Institutes of Health, Baltimore, MD 21224, USA
| | - Diane Teichberg
- The Research Resources Branch, National Institute on Aging-Intramural Research Program, National Institutes of Health, Baltimore, MD 21224, USA
| | - Dorothy Bertak
- Laboratory of Immunology, National Institute on Aging-Intramural Research Program, National Institutes of Health, 5600 Nathan Shock Drive, Baltimore, MD 21224, USA
| | - Arnell Carter
- Laboratory of Immunology, National Institute on Aging-Intramural Research Program, National Institutes of Health, 5600 Nathan Shock Drive, Baltimore, MD 21224, USA
| | - Suresh Poosala
- The Research Resources Branch, National Institute on Aging-Intramural Research Program, National Institutes of Health, Baltimore, MD 21224, USA
| | - Jeffrey Firman
- The Research Resources Branch, National Institute on Aging-Intramural Research Program, National Institutes of Health, Baltimore, MD 21224, USA
| | - Kevin G. Becker
- The Research Resources Branch, National Institute on Aging-Intramural Research Program, National Institutes of Health, Baltimore, MD 21224, USA
| | - Alan B. Zonderman
- The Research Resources Branch, National Institute on Aging-Intramural Research Program, National Institutes of Health, Baltimore, MD 21224, USA
| | - Dan L. Longo
- Laboratory of Immunology, National Institute on Aging-Intramural Research Program, National Institutes of Health, 5600 Nathan Shock Drive, Baltimore, MD 21224, USA
| | - Dennis D. Taub
- Laboratory of Immunology, National Institute on Aging-Intramural Research Program, National Institutes of Health, 5600 Nathan Shock Drive, Baltimore, MD 21224, USA
- Corresponding author. Fax: +1 410 558 8284. E-mail address: (D.D. Taub)
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Arudchelvan Y, Tokuda N, Adachi Y, Sawada T, Fukumoto T. Ultrastructural alterations of the cortical epithelial cells of the irradiated and recovering rat thymus. ACTA ACUST UNITED AC 2006; 68:205-12. [PMID: 16276026 DOI: 10.1679/aohc.68.205] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
To understand the roles of cortical thymic epithelial cells (CTECs) in T-lymphocyte development, we analyzed rat thymi recovering from irradiation (6Gy), at the ultrastructural level. The morphological alterations in the CTECs were most prominent during the third to fifth day of recovery, when proliferating thymocytes were observed in the vicinity of the CTECs. The most striking finding among the alterations in the CTECs after irradiation was a cytoplasmic vacuolization with an increased amount of granular and membranous content. The granular content was observed as loosely aggregated structures or finely dispersed granules and dense bodies. The membranous content appeared in various forms including vesicular, tubular, and irregular membranous structures and myelin figures. The above features are characteristic of the hyperfunctional state of CTECs with increased secretion activities, which suggests their important roles in the repopulation and maturation of the cortical thymocytes during recovery after irradiation.
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Affiliation(s)
- Yamini Arudchelvan
- Department of Human Science, Yamaguchi University School of Medicine, Ube, Japan.
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Irifune T, Tamechika M, Adachi Y, Tokuda N, Sawada T, Fukumoto T. Morphological and immunohistochemical changes to thymic epithelial cells in the irradiated and recovering rat thymus. ACTA ACUST UNITED AC 2005; 67:149-58. [PMID: 15468954 DOI: 10.1679/aohc.67.149] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The present study analyzed morphological and immunohistochemical changes of thymic epithelial cells in the irradiated and recovering rat thymus. Observations showed the number of thymocytes was initially severely reduced after irradiation but abruptly increased on days 3 to 5 after 6 Gy and on days 7 to 11 after 8 Gy irradiation. To analyse the mechanisms for this abrupt recovery of the thymocytes after irradiation, the expression of p63 in the normal and irradiated thymus was immunohistochemically studied as the expression of this antigen may be related to the proliferation of epithelial cells. In the fetal thymus tissue, thymic epithelial cells were the principal cell type that stained strongly positive for p63. The sporadic expression of p63 was also observed in the normal adult thymus tissue, especially in the subcapsular region. An increased number of p63- positive cells in the thymus after irradiation indicates that repair or renewal of the thymic epithelial cells may be taking place because p63 is more specific to transient amplifying thymic epithelial cells. A RT-PCR analysis of p63 expression in irradiated and regenerating thymus tissue also showed an increased expression of p63 after irradiation compared with that of the normal thymus. These results suggest that changes in the thymic microenvironment-especially in relation to the repair and renewal of thymic epithelial cells- may have an important influence on thymocyte proliferation in the normal thymus as well as in the irradiated and recovering thymus.
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Affiliation(s)
- Tatsuya Irifune
- Department of Human Science, Yamaguchi University School of Medicine, Ube, Yamaguchi, Japan.
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Tokuda N, Hamasaki K, Mizutani N, Adachi Y, Sawada T, Funahashi H, Shioda S, Fukumoto T. Expression of PAC1 receptor in rat thymus after irradiation. ACTA ACUST UNITED AC 2004; 123:167-72. [PMID: 15518908 DOI: 10.1016/j.regpep.2004.04.028] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In the present work, PAC1-R (G-protein-coupled receptor specific for PACAP) was detected on cells in the normal thymus. Immunohistochemically PAC1-R was expressed strongly in stromal cells of the thymic medulla. Positive cells were also observed in the thymus of fetal and old adult rats. After 8 Gy irradiation to 9-week-old rats, PAC1-R expressions in the thymus decreased and almost recovered by day 21. The expression of PAC1-R mRNA was weak in the thymus and decreased further after irradiation. The expression almost recovered by day 28. Hip and hip/hop variants, which were not expressed in the normal thymus, were expressed in the thymus on days 3, 5 and 21 after irradiation. The expressions of IL-6 and IL-10 tended to increase initially after irradiation then decreased. Histologically, the thymic structures were destroyed on day 3 after irradiation and the thymus almost recovered by day 21. Thus PACAP is thought to be one of the important factors for cross-talk between cells involved in thymic regeneration.
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Affiliation(s)
- Nobuko Tokuda
- Department of Human Science, Yamaguchi University School of Medicine, Ube 755-8505, Japan.
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