Coumarin-derived imino sulfonate 5h ameliorates cardiac injury induced by myocardial infarction via activating the Sirt1/Nrf2 signaling pathway

Myocardial infarction (MI) is irreversible damage caused by ischemia and hypoxia in coronary arteries accompanied by elevated catecholamine levels, leading to the accumulation of free radicals. Our previous study discovered coumarin-derived imino sulfonates as a novel class of potential cardioprotective agents possessing strong anti-oxidative effects in cardiomyocytes. Therefore, identifying the compound with the highest cardioprotective activity, 5h, and the mechanism involved was necessary. As a kind of catecholamine, isoproterenol can clinically induce myocardial infarction injury similar to the symptoms of myocardial infarction patients. Our experiments explored the underlying mechanism of this effect of compound 5h by assessing cardiac function, infarct size, histopathological changes, and downregulation of Sirt1 by transfection of adenovirus in vitro and by administering Ex527, a specific inhibitor of Sirt1, in vivo. Compound 5h exhibited strong cardioprotective actions in vivo and in vitro via improving cell survival and cardiac function and decreasing the cellular oxidative stress and cardiac infarct size against MI. Furthermore, compound 5h significantly enhanced cardiac expression of Sirt1, subsequently activating the Nrf2/NQO1 signaling pathway. However, adenovirus-induced Sirt1 downregulation or Sirt1-specific inhibitor largely blocked such beneficial effects of 5h in vitro and in vivo, respectively. Taken together, our results demonstrated, for the first time, that the cardioprotective action of 5h against MI was mediated by reducing oxidative stress and apoptosis through the Sirt1/Nrf2 signaling pathway. Our findings proposed novel insights in developing and evaluating coumarin-derived imino sulfonate compounds as epigenetics-targeted drug therapy for MI.