Hypoxia induces autophagy in human vascular endothelial cells in a hypoxia-inducible factor 1-dependent manner

Hypoxia has been widely implicated in numerous pathological conditions, including those associated with inflammation and tumorigenesis. A number of recent studies have implicated hypoxia in the control of microvascular damage, the basis for which is not fully understood. In the present study, it was identified that autophagy was induced in human umbilical vein endothelial cells (HUVECs) post treatment with hypoxia, and the induction of autophagy by hypoxia was enhanced by hypoxia-inducible factor 1 (HIF-1) gene overexpression and inhibited by HIF-1 knockout. Furthermore, the autophagy induced by overexpression of HIF-1 was associated with a reduction of HUVEC cell viability. Therefore, HIF-1 reduced HUVEC cell viability by inducing autophagy. These findings provide evidence of an important link between hypoxia and microvascular damage associated with HIF-1-related autophagy.