Research Papers:

ABSTRACT

Chronic intermittent hypoxia (CIH) in obstructive sleep apnea causes damages of aortic endothelial cells, which predisposes development of many cardiovascular diseases. Recently, both altered expression of microRNAs (miRNAs) and impaired autophagy were found to be associated with endothelial cell dysfunction in CIH. However, the exact molecular regulatory pathway has not been determined. Here, we addressed this question. In a mouse model of CIH, we detected significant upregulation of miR-30a, a miRNA that targets 3′-UTR of autophagy-associated protein 6 (Beclin-1) mRNA to suppress the protein translation, which subsequently attenuated the endothelial cell autophagy against cell death. Indeed, unlike Beclin-1 mRNA, the Beclin-1 protein in endothelial cells did not increase after CIH. Suppression of miR-30a by expression of antisense of miR-30a significantly increased Beclin-1 levels to enhance endothelial cell autophagy in vitro and in vivo, which improved endothelial cell survival against CIH. Together, these data suggest that endothelial cell autophagy in CIH may be attenuated by miR-30a-mediated translational control of Beclin-1, as an important cause of endothelial cell dysfunction and damage.