IPC Protect Cardiomycytes From Autophagy Clear Of Ischemia Reperfusion Via DRP1-mediated-mitophagy

Background Ischemic heart disease(IHD)is one of the most threatening cardiovascular diseases to human health.We previously reported that autophagy is required for cardioprotection by ischemic preconditioning(IPC).But ischemia reperfusion leads to ischemia reperfusion injury(IRI)by triggerring execssive autophagy.How mild and transient oxidative stress can avoid autophagy-induced autophagic cell death is an open question.Our study sought to examine whether IPC is associated with dynamic-related-protein1(DRP1)dependent mitophagy in cardioprotection.Methods In cell experiments,We transfect H9C2 myocardiocytes with mito Ds Red(red)and CD63-GFP(green).Exposing H9C2 myocardiocytes into H2O2 culture medium and HBSS culture medium to inducing mild and transient oxidative stress model and non-selective autophagy model.Then(1)testingthe level of ROS;(2)observing mitochondrail morphology and the colocation of mitochondrail and autophagosome with confocal fluorescence microscopy;(3)observing cell ultrastructure with electron microscopy.We block out drp1 with drp1-si RNA.Exposing them into H2O2 culture medium and HBSS culture medium to testing the level of autophagy substrate proteins.In animal experiment,We construct Langendorff-Perfusion model to observing how mi RNA499 affect myocardiocyctes autophagy in I/R condition.Results We found that H2O2 leads to moderately elevated ROS levels which could induce mitophagy without triggering non-selective autophagy.HBSS can induce both mitophagy and non-selective autophagy.Drp1 was silenced by drp1 si RNA,which blocked mitophagy induction by H2O2 while the non-selective autophagy was not affected.Taken together,we demonstrate that DRP1 mediates mitophagy.The animal experiment proves that mi R-499 can inhibit the acitivty of DRP1,reduce mitophagy which is triggered by IPC.The conclusion also proves that IPC protect myocardial cell via DRP1-mediated-mitophagy pathway..Conciusion Our data indicate that moderately elevated ROS can induce mitophagy without trigger non-selective autophagy.IPC protect myocardial cell from ROS and ischemia reperfusion injury via drp1-mediated-mitophagy pathway.