HIF-1α/BNIP3 signaling pathway-induced-autophagy plays protective role during myocardial ischemia-reperfusion injury

Objective: The study was established to inquire into the protective effect of the HIF-1 alpha (Hypoxia-inducible factor-1 alpha)/ BNIP3(Bcl-2/adenovirus E1B 19-kDa interacting protein) signal path-induced-autophagy during myocardial ischemia/ reperfusion (I/R) and oxygen-glucose deprivation/recovery (OGD/R) injury in heart-derived H9C2 cells as well as its potential underlying mechanism. Methods: Immediate myocardial I/R in SD (Spraque Dawley) rats and cytotoxicity of OGD/R injury on H9C2 cells with and without inhibitors or agonists of HIF-1 alpha and BNIP3 were evaluated. Expression of mitochondrial autophagic protein were detected by Western blot and immunofluorescence. And the mitochondrial autophagosome were detected using Transmission Electron Microscope (TEM). Results: I/R and OGD/R injury increased the expression level of HIF-1 alpha, activated the downstream BNIP3 and subsequently triggered mitochondria-dependent autophagy. Up-regulation the expression of HIF-1 alpha and BNIP3 may promote the cardiac myocytes of SD rats of I/R injure and OGD/R injury-induced autophagy of H9C2 cells. Moreover, down-regulation the expression of HIF-1 alpha or BNIP3-siRNA decreased H9C2 cells autophagy under OGD/R injury. Conclusions: Together, our studies indicated that HIF-1 alpha synchronization regulate BNIP3 during OGD/R injury-induced autophagy in H9C2 cells, though BNIP3-induced autophagy acting as a survival mechanism.