SIRT1 Mediates the Effects of Sera from Athletes Who Engage in Aerobic Exercise Training in Activating Cells for Wound Healing.

Background/Objectives: Exercise training (ET) can improve wound healing and prevent the recurrence of skin lesions. Aerobic ET stimulates the NAD+-dependent deacetylase sirtuin 1 (SIRT1). The beneficial effects of ET and SIRT1 activation in wound healing have been characterized when considered separately. This study aimed to investigate the potential role of SIRT1 as a mediator of the effects of sera isolated from athletes who regularly participate in aerobic ET (middle-distance running, MDR) on cells primarily involved in wound healing. Methods: Human keratinocytes, fibroblasts and endothelial cells were conditioned with sera from middle-distance runners and age-matched sedentary subjects (sed). Cell motility, angiogenesis and the expression of key biomarkers of cell activation were evaluated in the presence or absence of the selective SIRT1 inhibitor EX-527. Results: Higher SIRT1 activity was detected in all of the cell lines conditioned with the MDR group sera compared with that in the cells in the sed group sera. The involvement of SIRT1 was demonstrated by EX-527's selective inhibition. Alongside the increase in SIRT1 activity, a marked increase in migration, invasion and angiogenesis was observed. The levels of E-cadherin decreased while those of integrin β1 and vinculin increased in the keratinocytes and fibroblasts conditioned with the MDR group sera compared to these values with the sed group sera, respectively. Increased levels of differentiation markers, such as involucrin in the keratinocytes, FAP1α in the fibroblasts and CD31 in the endothelial cells, were observed with the MDR group sera compared to these values using the sed group sera. Conclusions: The ex vivo/in vitro approach used here links aerobic ET-induced SIRT1 activity to proper tissue regeneration.