Rab32 protects mitochondrial function by anchoring Fancd2 and mediates the protective effect of penehyclidine hydrochloride against myocardial ischemia-reperfusion injury.

Myocardial cell injury resulting from myocardial ischemia and reperfusion is one of the primary drivers behind the onset and progression of heart disease. Penehyclidine hydrochloride (PHC), a novel selective anti-cholinergic agent, exerts a protective effect against myocardial ischemia-reperfusion injury (MIRI). Rab32 belongs to the family of small GTPase proteins. The present study aimed to investigate whether PHC improved MIRI by regulating Rab32 and to explore the underlying mechanisms. Oxygen-glucose deprivation/reoxygenation (OGD/R) and left anterior descending coronary artery ligation were used to establish MIRI models in vitro and in vivo. Here, we showed that PHC upregulated the expression of Rab32 in OGD/R treated HL-1 cells. PHC alleviated OGD/R-induced cell apoptosis and intracellular and mitochondrial ROS levels, while the downregulation of Rab32 exacerbated cell injury. Rab32 was upregulated in MIRI mice and downregulated in OGD/R-induced HL-1 cells. Rab32 overexpression improved cardiac function, reduced the myocardial infarct size, and inhibited cell apoptosis and mitochondrial dysfunction, either in MIRI mice or OGD/R-induced HL-1 cells. On the mechanism, Rab32 interacted with Fancd2 in HL-1 cells. Rab32 downregulation decreased Fancd2 protein expression in mitochondria. Rab32 anchored Fancd2 to mitochondria in OGD/R treated HL-1 cells. Fancd2 knockdown reversed the protective effect of Rab32 on OGD/R-induced HL-1 cells and aggravated cardiomyocyte injury. Finally, the protective role of PHC on MIRI-caused cardiomyocyte injury was confirmed in MIRI mice. Overall, we demonstrated that Rab32 protects mitochondrial function by anchoring Fancd2 and mediates the protective effect of PHC against MIRI.