RasGRP2 Attenuates Oxygen Deprivation-Induced Autophagy in Vascular Endothelial Cells.

Vascular endothelial cells sustain vascular health through barrier and endocrine functions. Insufficient oxygen supply induces endothelial dysfunction in the pathology of various diseases. In addition, oxygen deprivation reportedly induces endothelial dysfunction via autophagy. Ras guanyl-releasing protein 2 (RasGRP2) has guanosine 5'-diphosphate (GDP)/guanosine 5'-triphosphate (GTP) exchange factor activity and activates Rap1 and R-Ras which belong to the small GTPases. RasGRP2 exerts protective effects against vascular endothelial dysfunction. However, the effect of RasGRP2 on hypoxic stress in vascular endothelial cells has not yet been investigated. We examined the protein expression of hypoxia-inducible factor (HIF)-1α, BCL2 interacting protein 3 (BNIP3), and microtubule-associated protein light chain 3β (LC3β). We observed that oxygen deprivation increased the expression of HIF-1α, BNIP3 and LC3β II. RasGRP2 suppressed the induction of HIF-1α and the subsequent increase in LC3β II. These findings suggest the possibility that RasGRP2 plays a protective role against endothelial dysfunction by suppressing oxygen deprivation-induced autophagy.