Ischemic post-conditioning promotes mitochondrial translocation of DJ-1 and stabilizes binding to Bcl- xL to attenuate myocardial ischemic-reperfusion injury in STZ-induced diabetic rats

Abstract Background Ischemic post-conditioning (IPO) is a strategy in reducing myocardial ischemic-reperfusion (I/R) injury, but its specific molecular mechanism is incompletely understood. Deletions or mutations in the DJ-1 gene are directly linked to the cardiovascular system. DJ-1 plays a critical role in regulating mitochondrial homeostasis in response to stress through translocation of DJ-1 from the cytoplasm into the nucleus. Meanwhile, how the DJ-1 is removed in myocardial I/R injury and regulating apoptosis is needed to further verified. Given the discovery mentioned above, we hypothesize that DJ-1 translocate to mitochondria recover IPO induced cardioprotection in STZ-induced diabetic rats. To evaluate our hypothesis, we overexpressed the DJ-1 protein under high glucose condition, subjected IPO or not. And then measure the expression of DJ-1 in mitochondria and cytoplasm after myocardial I/R. Results We found that DJ-1 translocated to mitochondria combined with Bcl-xL was reduced cardiomyocyte injury and apoptosis in diabetic myocardial I/R heart. Additionally, the binding of DJ-1 and Bcl-xL is dependent on the oxidative state of DJ-1(oxidation of DJ-1 at Cys-106 is important for its protective effect). Conclusions If our hypothesis is correct, promote DJ-1 mitochondrial transfer may be critical with respect to restoring myocardial responsiveness to IPO in diabetes.