Mitochondria-targeted Hydrogen Sulfide exerts protective effects and maintains mitochondria homeostasis against ischemia reperfusion injury in heart transplantation via the mitofusion-1 pathway

Abstract Objective Ischemia-reperfusion injury (IRI) occurring in heart transplantation (HTx) is adversely associated with primary graft dysfunction. New strategies to preserve donor heart function and reduce IRI are urgently needed, especially with prolonged ischemia time. In this study, we hypothesized that supplementing preservation solution with mitochondria-targeted hydrogen sulfide (AP39) exerts cardioprotective effects against IRI via the mitofusion-1 (Mfn1) pathway and modulating cardiometabolic profiles. Methods An in vitro hypoxia-reoxygenation H9C2 cell model was utilized to investigate cardiomyocyte viability, apoptosis and mitochondria homeostasis. Besides, mitochondria dynamic related proteins were examined. For in vivo study, a rat heterotopic HTx model was utilized. SD rats were divided into the control group, AP39 group and AP39+ Mfn siRNA group. The donor hearts were subjected to 16hours of preservation at 4°C and then transplanted into receipt rats. Cardiac function, histology, and mitochondria morphology were assessed at postoperative day 3. Furthermore, we investigated the alterations of cardiometabolic profiles in the donor grafts by LC-MS/MS. Results 50nM AP39 treatment exhibited the most favorable protective effects against cold IRI in vitro. AP39 treatment significantly increased Mfn1 expression, while the expression of other mitochondria-dynamic molecules remained unchanged. AP39 treatment significantly reduced cell apoptosis and inflammation. As for mitochondria parameters, AP39 treatment significantly increased Mitotracker™ Red fluorescence cells but decreased MitoSox™ Green fluorescence cells, as well as preserved mitochondria morphology. However, all the protective effects of AP39 treatment were diminished by knockdown of Mfn1using siRNA. For in vivo study, donor graft preserved with AP39 treatment significantly enhanced cardiac function, decreased tissue damage and apoptosis in donor grafts, as well as maintained mitochondria morphology. However, all the protective effects of AP39 treatment were reversed by knockdown of Mfn1. Moreover, three overlapping differential metabolites involved in the glycerophospholipid metabolism, fatty acyls metabolism and citric acid cycle were identified. Conclusion Mitochondria-targeted hydrogen sulfide exerted protective effects against IRI in HTx and maintained mitochondria homeostasis. The protective effects were associated with the Mfn1 pathway and modulating cardiometabolic profiles.