Laminar Shear Stress Protects Against Premature Endothelial Senescence by SIRT1-Dependent Mechanisms

PURPOSE:Accumulation of senescent endothelial cells (ECs) and development of vascular aging have been implicated in the etiology of vascular dysfunction and disease. Aerobic exercise has been recognized as the single most effective non-pharmacological anti-aging intervention via increased laminar shear stress (LSS). This study aimed to determine the protective effects of LSS against premature senescence and the underlying mechanism.METHODS: Carotid artery partial ligation surgery was performed on the left carotid arteries (LCAs) of C57BL/6J male mice to determine the effect of disturbed flow on the development of endothelial senescence. Senescence-associated β-galactosidase (SA-β-gal) staining was performed to measure cellular senescence. Expression levels of protein markers for cell senescence including p21, p16, and p53 were measured by western blotting.RESULTS: En face SA-β-gal staining was identified only in the partially ligated LCAs of voluntary wheel-running mice, suggesting a direct relevance of LSS on the prevention of vascular senescence. In the in vitro H₂O₂-induced premature senescence model, preconditioning of high-flow LSS (20 dyne/cm2, 36 hours) induced significant reduction in the percentage of SA-β-gal positive ECs. Expression of the molecular markers of cellular senescence such as p21, p16, and p53 was significantly decreased by LSS pretreatment. However, the protective effects of LSS against premature senescence were completely abolished by SIRT1 inhibition.CONCLUSIONS: The results suggest that high-flow LSS has protective effects against oxidative stress-induced premature endothelial senescence through a SIRT1-dependent mechanism.