Alda-1 treatment promotes the therapeutic effect of mitochondrial transplantation for myocardial ischemia-reperfusion injury

Mitochondrial damage is a critical driver in myocardial ischemia-reperfusion (I/R) injury and can be alleviated via the mitochondrial transplantation. The efficiency of mitochondrial transplantation is determined by mitochondrial vitality. Because aldehyde dehydrogenase 2 (ALDH2) has a key role in regulating mitochondrial homeostasis, we aimed to investigate its potential therapeutic effects on mitochondrial transplantation via the use of ALDH2 activator, Alda-1. Our present study demonstrated that time-dependent internalization of exogenous mitochondria by cardiomyocytes along with ATP production were significantly increased in response to mitochondrial transplantation. Furthermore, Alda-1 treatment remarkably promoted the oxygen consumption rate and baseline mechanical function of cardiomyocytes caused by mitochondrial transplantation. Mitochondrial transplantation inhibited cardiomyocyte apoptosis induced by the hypoxia-reoxygenation exposure, independent of Alda-1 treatment. However, promotion of the mechanical function of cardiomyocytes exposed to hypoxia-reoxygenation treatment was only observed after mitochondrial Alda-1 treatment and transplantation. By using a myocardial I/R mouse model, our results revealed that transplantation of Alda-1-treated mitochondria into mouse myocardial tissues limited the infarction size after I/R injury, which was at least in part due to increased mitochondrial potential-mediated fusion. In conclusion, ALDH2 activation in mitochondrial transplantation shows great potential for the treatment of myocardial I/R injury.