Background and Purpose: Our previous research discovered that cinnamamide derivatives are a new type of potential cardioprotective agents myocardial ischemia-reperfusion (MIR) injury, among which Compound 10 exhibits wonderful beneficial action in vitro. However, the exact mechanism of Compound 10 still needs to be elucidated. Experimental Approach: The protective effect of Compound 10 was determined by detecting the cell viability and LDH leakage rate in H9c2 cells subjected to H2O2. Alterations of electrocardiogram, echocardiography, cardiac infarct area, histopathology and serum myocardial zymogram were tested in MIR rats. Additionally, the potential mechanism of Compound 10 was explored through PCR. Network pharmacology and Western blotting was conducted to monitor levels of proteins related to autophagic flux and mTOR, autophagy regulatory substrate, induced by Compound 10 both in vitro and in vivo, as well as expressions of Sirtuins family members. Key Results: Compound 10 significantly ameliorated myocardial injury, as demonstrated by increased cell viability, decreased LDH leakage in vitro, and declined serum myocardial zymogram, ST elevation, cardiac infarct area and improved cardiac function and microstructure of heart tissue in vivo. Importantly, Compound 10 markedly enhanced the obstruction of autophagic flux and inhibited excessive autophagy initiation against MIR by decreased P-mTOR and increased LAMP2. Furthermore, Sirt1 knockdown hindered Compound 10’s regulation on mTOR, leading to interrupted cardiac autophagic flux. Conclusions and Implications: Compound 10 exerted cardioprotective effects on MIR by reducing excessive autophagy and improving autophgic flux blockage. Our work would take a novel insight in seeking effective prevention and treatment strategies against MIR injury. Keywords: Myocardial ischemia-reperfusion; Cinnamamide derivatives; Autophagic flux; Sirt1; mTOR;

Background and Purpose Myocardial ischemia/reperfusion (MI/R) injury is the main clinical problem of coronary heart disease. Higenamine (HG), a cardiotonic active component isolated from aconiti tuber, exhibits cardioprotective effects. However, its exact mechanism in MI/R is limited. Experimental Approach The oxidative stress induced by H2O2 in H9c2 and MI/R rat model was established. Metprolol, evidenced to ameliorate MI/R injury, was used as the positive control. Cardiac impairment indexes, were detected in vitro and in vivo. Changes of peroxiredoxins (Prxs), important anti-oxidative stress proteins in MI/R were also evaluated. Adenovirus induced Prx2 down-regulation and specific inhibitor of Prx2 was employed to determine the exact mechanism of HG in vitro and in vivo. Metabolomic analysis of MI/R rats with or without HG administration based on UPLC-MS/MS was further performed. Key Results HG significantly reduced the oxidative stress, improve cardiac dysfunction and decrease cardiac infarct size against MI/R via Prx2 activation, which was stronger than those in positive control treated rats. Additionally, HG altered metabolism of arginine and proline and biosynthesis of arginine during MI/R. Mechanically, HG increased the levels of Prx2, accompanied with decreased apoptotic protein, in vitro and in vivo expressions. However, down-regulation of Prx2 markedly blocked all the cardioprotective effect of HG. Conclusion and Implications Our work systematicly demonstrated that HG possessed a strong cardioprotective effect against MI/R by up-regulating cardiac expression of Prx2 and modulating disordered metabolism of arginine and glutamine in heart. We provided HG as the potential to further explore therapeutic strategy for MI/R.

Background and Purpose: Myocardial infarction (MI) is an irreversible damage caused by ischemia and hypoxia in coronary arteries accompanied with elevated levels of catecholamine, 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 effect in cardimyocytes. Therefore, the identification of the compound with the highest cardioprotective activity, 5h, and the mechanism involved was necessary. Experimental Approach: As a kind of catecholamine, isoproterenol induces MI injury mimicking symptoms of MI patients in clinic. Cardiac function, nfarct area, histopathological changes were evaluated. The potential mechanism underlying such action of compound 5h was explored via transfection with adenovirus to downregulate Sirt1 in vitro, and by administration of Ex527, the specific inhibitor for Sirt1, in vivo. Key Results: Compound 5h exhibited strong cardioprotective actions in vivo and in vitro via improving cell survival, 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. Conclusions and Implications: 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 the development and evaluation of coumarin-derived imino sulfonate compounds as epigenetics-targeted drug therapy for MI.