Estrogen receptor alpha mediates 17 beta-estradiol, up-regulates autophagy and alleviates hydrogen peroxide-induced vascular senescence

Atherosclerosis threatens human health by developing cardiovascular diseases, the deadliest disease world widely. The major mechanism contributing to the formation of atherosclerosis is mainly due to vascular endothelial cell (VECs) senescence. We have shown that 17 beta-estradiol (17 beta-E-2) may protect VECs from senescence by upregulating autophagy. However, little is known about how 17 beta-E-2 activates the autophagy pathway to alleviate cellular senescence. Therefore, the aim of this study is to determine the role of estrogen receptor (ER) alpha and beta in the effects of 17 beta-E-2 on vascular autophagy and aging through in vitro and in vivo models. Hydrogen peroxide (H2O2) was used to establish Human Umbilical Vein Endothelial Cells (HUVECs) senescence. Autophagy activity was measured through immunofluorescence and immunohistochemistry staining of light chain 3 (LC3) expression. Inhibition of ER activity was established using shRNA gene silencing and ER antagonist. Compared with ER-beta knockdown, we found that knockdown of ER-alpha resulted in a significant increase in the extent of HUVEC senescence and senescence-associated secretory phenotype (SASP) secretion. ER-alpha-specific shRNA was found to reduce 17 beta-E-2-induced autophagy, promote HUVEC senescence, disrupt the morphology of HUVECs, and increase the expression of Rb dephosphorylation and SASP. These in vitro findings were found consistent with the in vivo results. In conclusion, our data suggest that 17 beta-E-2 activates the activity of ER-alpha and then increases the formation of autophagosomes (LC3 high expression) and decreases the fusion of lysosomes with autophagic vesicles (P62 low expression), which in turn serves to decrease the secretion of SASP caused by H2O2 and consequently inhibit H2O2-induced senescence in HUVEC cells.

Automated summary

Atherosclerosis, a major cause of cardiovascular diseases, is mainly caused by vascular endothelial cell (VECs) senescence. It has been shown that 17 beta-estradiol (17 beta-E-2) can protect VECs from senescence by activating autophagy, but the underlying mechanism is still unclear. This study aims to investigate the role of estrogen receptor (ER) alpha and beta in the effects of 17 beta-E-2 on vascular autophagy and aging using in vitro and in vivo models.