Adiponectin inhibits proliferation of vascular endothelial cells induced by Ox-LDL by promoting dephosphorylation of Caveolin-1 and depolymerization of eNOS and up-regulating release of NO

Oxidized low density lipoprotein (ox-LDL) can induce the proliferation and differentiation of endothelial cells, which is one of the important mechanisms of ox-LDL atherosclerosis. Adiponectin is an endogenous bioactive polypeptide secreted by adipocytes, it participates in the metabolism of fat and glucose. It has the effect of reducing blood triglyceride and LDL content. Adiponectin also inhibits the abnormal proliferation and migration of endothelial cells, but its molecular mechanism is unclear. In this study, we used cell model of Ox-LDL-induced human aortic endothelial cells (HAECs) proliferation to analyze the molecular mechanism of APN inhibiting HAECs abnormal proliferation. The results showed that APN could inhibit the cell viability and DNA synthesis of HAECs after Ox-LDL treatment, up-regulate the apoptosis level and reduce the proportion of S + G2 phase cells. Further analysis showed that adiponectin could promote the dephosphorylation of Caveolin-1, which could dissociate eNOS and Caveolin-1, promote the phosphorylation of eNOS and enhance the synthesis of NO. NO increased expression levels of cleaved caspase 3 and p21 in the cells and inhibited the abnormal proliferation of HAECs. The regulation of phosphorylation and dephosphorylation of Caveolae-1 plays a key role in this process. Further study of the molecular mechanism of Caveolae-1 in the inhibition of HAECs abnormal proliferation by APN may reveal the potential of APN in the treatment of cardiovascular diseases.