Glucocorticoid (GC) and prolactin (PRL) are the two neuroendocrines that regulate thymocyte differentiation and maintain the immune homeostasis during stress. We found that dexamethasone (Dex), a synthetic GC, induced apoptosis in normal immature cortical thymocytes which remained unaltered in the presence of Elrich's ascitic carcinoma (EAC). PRL protected the normal CD4+ CD8+ cortical thymocytes from Dex-induced apoptosis but failed to alter the effect of Dex in tumor-bearing mice. Dex-treated normal thymocytes became unresponsive to PRL in presence of tumor cell culture supernatant. Low binding affinity of the microsomal membranes of thymocytes to PRL and absence of the mRNA of a particular form of prolactin receptor (PRL-R) suggest the presence of a different PRL-R in CD4+ CD8+ thymocytes of EAC-bearing mice. The induction of tumor may alter the PRL-R that can be correlated with the failure of PRL in rescuing CD4+ CD8+ immature cortical thymocytes from GC induced death.
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http://dx.doi.org/10.1016/j.jneuroim.2005.09.014 | DOI Listing |
Front Endocrinol (Lausanne)
November 2024
Laboratory on Thymus Research, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, RJ, Brazil.
Galectin-3 is an endogenous lectin which binds mainly to β-galactosides on the cell surface and extracellular matrix (ECM) glycoproteins. In the thymus, this lectin is constitutively expressed, being involved in thymocyte adhesion, migration, and death. Galectin-3 has been related to type 1 diabetes, an autoimmune disease characterized by pancreatic β-cell destruction mediated by autoreactive T lymphocytes.
View Article and Find Full Text PDFNat Immunol
December 2024
Laboratory for Transcriptional Regulation, RIKEN Center for Integrative Medical Sciences (IMS), Yokohama, Japan.
Genetic studies in mice have shown that the zinc finger transcription factor BCL11B has an essential role in regulating early T cell development and neurogenesis. A de novo heterozygous missense BCL11B variant, BCL11B, was isolated from a patient with T cell deficiency and neurological disorders. Here, we show that mice harboring the corresponding Bcl11b mutation show the emergence of natural killer (NK)/group 1 innate lymphoid cell (ILC1)-like NKp46 cells in the thymus and reduction in TBR1 neurons in the neocortex, which are observed with loss of Bcl11a but not Bcl11b.
View Article and Find Full Text PDFSci Adv
September 2024
Department of Physiology, McGill University, Montreal QC, Canada.
Central tolerance of thymocytes to self-antigen depends on the medullary thymic epithelial cell (mTEC) transcription factor autoimmune regulator (Aire), which drives tissue-restricted antigen (TRA) gene expression. Vitamin D signaling regulates Aire and TRA expression in mTECs, providing a basis for links between vitamin D deficiency and autoimmunity. We find that mice lacking Cyp27b1, which cannot produce hormonally active vitamin D, display profoundly reduced thymic cellularity, with a reduced proportion of Aire mTECs, attenuated TRA expression, and poorly defined cortical-medullary boundaries.
View Article and Find Full Text PDFJ Vis Exp
July 2024
Thymus Biology Section, Experimental Immunology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health;
Thymic epithelial cells (TECs) play an essential role in promoting the development and repertoire selection of T cells. Cortical TECs (cTECs) in the thymic cortex induce early T cell development and positive selection of cortical thymocytes. In contrast, medullary TECs (mTECs) in the thymic medulla attract positively selected thymocytes from the cortex and establish self-tolerance in T cells.
View Article and Find Full Text PDFImmunol Lett
October 2024
Department of Translational Research and New Surgical and Medical Technologies, University of Pisa, Pisa, Italy.
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.
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