Targeting the mitochondrial-associated endoplasmic reticulum membrane to regulate calcium homeostasis: ShenfuYixin Granules counteract myocardial ischemia-reperfusion injury through the sGC/PKG pathway

BACKGROUND: Myocardial ischemia-reperfusion injury (MIRI) constitutes a significant contributor to the increased incidence of post-ischemic heart failure. The primary mechanisms underlying MIRI involve oxidative stress and mitochondrial calcium overload in reperfused cardiomyocytes. Regulating the homeostasis of the mitochondrial-associated endoplasmic reticulum membranes (MAMs) to improve endoplasmic reticulum-mitochondrial communication is expected to treat MIRI, but there are currently no clear targeted drugs. The Shenfuyixin Granules (SFYX) exhibit capabilities in lowering reactive oxygen species levels, curtailing apoptosis, and improving mitochondrial performance in cardiomyocytes. However, its therapeutic role in MIRI remains unclear. AIM OF THE STUDY: This study aims to clarify the effect of SFYX on mitochondrial calcium overload after MIRI and elucidate its potential mechanism of action. METHODS: The rat MIRI model was established by short-time ligation of the left anterior descending coronary artery and reperfusion, and SXNI (3.275g/kg, 6.55g/kg, 13.1g/kg) was administered for treatment. Network pharmacology combined with molecular docking has revealed the specific molecular mechanism by which SFYX regulates mitochondrial calcium homeostasis in the myocardium. The improvement effect of SFYX on MIRI was evaluated by western blotting (WB), TUNEL staining, immunofluorescence staining, etc. A hypoxia/reoxygenation (H/R) model of myocardial cells was simultaneously established, MIRI was simulated in vitro, and the mechanism was verified using WB, fluorescent probes, mitochondrial function and other related tests. RESULTS: Network pharmacological analysis and molecular docking indicated that SFYX might improve MIRI by reducing mitochondrial calcium overload through the cGMP-PKG signaling pathway and calcium signaling pathway, and the key blood-entering components could stably bind to cGMP and PKG. In vivo experiments confirm that SFYX significantly attenuates myocardial injury associated with MIRI and alleviates levels of oxidative stress and apoptosis through the sGC/PKG pathway. In vitro experiments verify that SFYX regulates MAMs via the sGC/PKG signaling pathway, thereby stabilizing mitochondrial function, alleviating calcium overload and oxidative stress, and ultimately combating MIRI. CONCLUSION: This study suggests that SFYX prophylactic administration can alleviate mitochondrial calcium overload by targeting MAMs through the sGC/PKG signaling axis and has a preventive effect on MIRI. These findings indicate that SFYX may become a potential drug for preventing MIRI in the future.