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Journal article

Thymic epithelial cell support of thymopoiesis does not require Klotho

Abstract:
Age-related thymic involution is characterized by a decrease in thymic epithelial cell (TEC) number and function parallel to a disruption in their spatial organization, resulting in defective thymocyte development and proliferation as well as peripheral T cell dysfunction. Deficiency of Klotho, an antiaging gene and modifier of fibroblast growth factor signaling, causes premature aging. To investigate the role of Klotho in accelerated age-dependent thymic involution, we conducted a comprehensive analysis of thymopoiesis and peripheral T cell homeostasis using Klotho-deficient (Kl/Kl) mice. At 8 wk of age, Kl/Kl mice displayed a severe reduction in the number of thymocytes (10–100-fold reduction), especially CD4 and CD8 double-positive cells, and a reduction of both cortical and medullary TECs. To address a cell-autonomous role for Klotho in TEC biology, we implanted neonatal thymi from Klotho-deficient and -sufficient mice into athymic hosts. Kl/Kl thymus grafts supported thymopoiesis equivalently to Klotho-sufficient thymus transplants, indicating that Klotho is not intrinsically essential for TEC support of thymopoiesis. Moreover, lethally irradiated hosts given Kl/Kl or wild-type bone marrow had normal thymocyte development and comparably reconstituted T cells, indicating that Klotho is not inherently essential for peripheral T cell reconstitution. Because Kl/Kl mice have higher levels of serum phosphorus, calcium, and vitamin D, we evaluated thymus function in Kl/Kl mice fed with a vitamin D–deprived diet. We observed that a vitamin D–deprived diet abrogated thymic involution and T cell lymphopenia in 8-wk-old Kl/Kl mice. Taken together, our data suggest that Klotho deficiency causes thymic involution via systemic effects that include high active vitamin D levels.
Publication status:
Published
Peer review status:
Peer reviewed

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Publisher copy:
10.4049/jimmunol.1800670

Authors



Publisher:
American Association of Immunologists
Journal:
Journal of Immunology More from this journal
Volume:
201
Issue:
11
Pages:
3320-3328
Publication date:
2018-10-29
Acceptance date:
2018-09-28
DOI:
EISSN:
1550-6606
ISSN:
0022-1767


Pubs id:
pubs:927657
UUID:
uuid:12e22a83-b975-4753-adfb-64ec78ea241a
Local pid:
pubs:927657
Source identifiers:
927657
Deposit date:
2018-10-16

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