Tohoku J. Exp. Med., 2012, 226(4)

Hydrogen Sulfide Protects Cardiomyocytes from Myocardial Ischemia-Reperfusion Injury by Enhancing Phosphorylation of Apoptosis Repressor with Caspase Recruitment Domain

XIAOYI YAO,¹ GANG TAN,² CHANGJUN HE,² YAN GAO,³ SHANGHA PAN,² HONGCHI JIANG,² YINA ZHANG¹ and XUEYING SUN²

¹Department of Geriatrics, The Second Affiliated Hospital of Harbin Medical University, Harbin, P.R. China
²The Hepatosplenic Surgery Center, The First Affiliated Hospital of Harbin Medical University, Harbin, P.R. China
³Department of ICU, The Fourth Affiliated Hospital of Harbin Medical University, Harbin, P.R. China

Hydrogen sulfide (H₂S) displays an anti-apoptotic activity against myocardial ischemia reperfusion (MIR). Apoptosis repressor with caspase recruitment domain (ARC) is constitutively expressed in the heart and inhibits cell apoptosis when it is phosphorylated. Here, we investigated whether H₂S could inhibit apoptosis by affecting ARC phosphorylation using cultured rat cardiomyocytes and a rat model of MIR. Primary cardiomyocytes were prepared from hearts of newborn rats and were pre-incubated with NaHS, a donor of H₂S, for 60 min. Cardiomyocytes were subjected to hypoxia for 4 h, followed by reoxygenation for 2 h. The hypoxia and subsequent reoxygenation (H/R) significantly induced cell apoptosis, increased expression levels of Fas and FasL proteins, enhanced release of cytochrome c from mitochondria, and elevated caspase-3 activity, while H/R reduced ARC phosphorylation and increased the activity of calcineurin that dephosphorylates ARC. Pre-incubation with NaHS significantly attenuated the above effects through promoting ARC phosphorylation by reducing calcineurin activity and by increasing the activity of protein kinase casein kinase II (CK2) that phosphorylates ARC. In fact, TBB, a specific inhibitor of CK2, abolished the effects of NaHS. In rats undergoing MIR, NaHS significantly reduced the myocardial infarct size, cell apoptosis, calcineurin activity, and the expression levels of Fas, FasL and cleaved caspase-3 proteins, while NaHS increased ARC phosphorylation. In contrast, DL-propargylglycine, an inhibitor of cystathionine γ-lyase, the main enzyme for H₂S production in hearts, showed opposite effects to NaHS. The results indicate that H₂S inhibits apoptosis of cardiomyocytes induced by MIR through enhancing ARC phosphorylation.

keywords —— apoptosis; apoptosis repressor with caspase recruitment domain; cardiomyocytes; hydrogen sulfide; myocardial ischemia reperfusion

© 2012 Tohoku University Medical Press

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Tohoku J. Exp. Med., 2012, 226, 275-285

Correspondence: Yina Zhang, M.D., Department of Geriatrics, the Second Affiliated Hospital of Harbin Medical University, 150086 Harbin, P.R. China.

e-mail: yinazhanghmu@126.com.