Upregulation of sodium-glucose cotransporter 2 (SGLT2) expression in cultured senescent endothelial cells and in arterial sites at risk in vivo in rats

Abstract

Endothelial senescence is thought to promote endothelial dysfunction and the subsequent development of cardiovascular diseases. The EMPA-REG trial has shown that sodium-glucose cotransporter 2 (SGLT2) inhibition is associated with a reduced risk of cardiovascular mortality in type 2 diabetic patients, but the protective mechanism remains unclear. SGLT2 mRNA has not been detected in control endothelial cells (ECs). This study examined the possibility that SGLT2 contributes to endothelial senescence and dysfunction and, if so, to characterize the underlying mechanism. Endothelial cells isolated from porcine coronary arteries were used at passage 1. Senescence was assessed using senescence-associated beta-galactosidase activity (SA-beta-gal activity), protein level by Western blot analysis, oxidative stress using dihydroethidium, and NO formation by electronic paramagnetic resonance. Exposure of ECs to HG (25 mM) for 96 h increased the level of SA-beta-gal activity and of senescence markers (p21 and p16) and oxidative stress, decreased eNOS expression and NO formation, and increased the expression of VCAM-1 and tissue factor (TF). Both HG and H 2 O 2 induced the appearance of SGLT2 mRNA, increased SGLT2 protein level and SGLT2-mediated glucose entry in ECs. An increased expression level of SGLT2 and VCAM-1, and a down-regulation of eNOS were observed at arterial sites at risk (aortic cross) compared with those at low risk (thoracic aorta) in young rats. These findings indicate that premature ECs ageing is characterized by the down-regulation of NO formation and the expression of pro-atherothrombotic factors, and is associated with the redox-sensitive upregulation of SGLT2 expression promoting excessive glucose entry. The fact that an increased SGLT2 expression level is observed in vivo at arterial sites at risk, suggests that inhibition of SGLT2 might be an attractive strategy to protect the cardiovascular system.