Ewelina Kiernozek
University of Warsaw, Poland
Title: The infl uence of glucocorticoids on the day/night changes of thymus-deriving natural regulatory T cells development and function
Biography
Biography: Ewelina Kiernozek
Abstract
Natural CD4+CD25+Foxp3+ regulatory T (nTreg) cells develop in the thymus and migrate in the periphery as a mature population of T lymphocytes with suppressive activity. They play a crucial role in the maintenance self-tolerance and immune homeostasis. Furthermore, nTregs have signifi cant therapeutic potential in suppressing autoreactive T cells and protecting from autoimmune diseases and chronic infl ammation. Currently, the mechanisms regulating nTregs development are still unclear. One of the factors, but still little explored, aff ecting their development and regulation of immune function are glucocorticoids. It is known that glucocorticoids are produced mainly by the adrenal cortex under the control of HPA axis. The treatment of mice with a synthetic glucocorticoid hormone, dexamethasone (Dex) induces the increase of Foxp3 expression in CD4+CD25+ thymocytes and their suppressive function. Considering the important role of HPA axis and glucocorticoids as effector molecules in the regulation of the immune response we aimed to determine the content and function of thymic nTregs in males and females C57BL/6 mice aft er treatment with Dex (25mg/kg/body weight) in a day/night dependent fashion. Results indicated that glucocorticoids play a role in the survival and development of thymocytes, thus, infl uencing the distribution of thymocyte subsets. Their concentration in the thymus deriving from endogenous synthesis and exogenous supplementation in accordance with the circadian rhythm of their synthesis correlate with the content and function of CD4+CD25+Foxp3+ cells.