Key Laboratory of Hepatosplenic Surgery, Department of General Surgery, the First Affiliated Hospital of Harbin Medical University, Harbin, China.
Autophagy. 2012 Jun;8(6):954-62. doi: 10.4161/auto.19927. Epub 2012 Jun 1.
Hydrogen sulphide (H 2S) exerts a protective effect in hepatic ischemia-reperfusion (I/R) injury. However, the exact mechanism of H 2S action remains largely unknown. This study was designed to investigate the role of the PtdIns3K-AKT1 pathways and autophagy in the protective effect of H 2S against hepatic I/R injury. Primary cultured mouse hepatocytes and livers with or without NaHS (a donor of H 2S) preconditioning were exposed to anoxia/reoxygenation (A/R) and I/R, respectively. In certain groups, they were also pretreated with LY294002 (AKT1-specific inhibitor), 3-methyladenine (3MA, autophagy inhibitor) or rapamycin (autophagy enhancer), alone or simultaneously. Cell viability, expression of P-AKT1, T-AKT1, LC3 and BECN1 were examined. The severity of liver injury was measured by the levels of serum aminotransferase and inflammatory cytokine, apoptosis and histological examination. GFP-LC3 redistribution and transmission electron microscopy were used to test the activity of autophagy. H 2S preconditioning activated PtdIns3K-AKT1 signaling in hepatocytes. LY294002 could abolish the AKT1 activation and attenuate the protective effect of H 2S on hepatocytes A/R and hepatic I/R injuries. H 2S suppressed hepatic autophagy in vitro and in vivo. Further reducing autophagy by 3MA also diminished the protective effect of H 2S, while rapamycin could reverse the autophagy inhibitory effect and enhance the protective effect of H 2S against hepatocytes A/R and hepatic I/R injuries, consequently. Taken together, H 2S protects against hepatocytic A/R and hepatic I/R injuries, at least in part, through AKT1 activation but not autophagy. An autophagy agonist could be applied to potentiate this hepatoprotective effect by reversing the autophagy inhibition of H 2S.
硫化氢（H 2S）在肝缺血再灌注（I/R）损伤中发挥保护作用。然而，H 2S 作用的确切机制在很大程度上仍然未知。本研究旨在探讨 PtdIns3K-AKT1 途径和自噬在 H 2S 对肝 I/R 损伤的保护作用中的作用。原代培养的小鼠肝细胞和肝脏分别用或不用 NaHS（H 2S 的供体）预处理，然后进行缺氧/复氧（A/R）和 I/R。在某些组中，还单独或同时用 LY294002（AKT1 特异性抑制剂）、3-甲基腺嘌呤（3MA，自噬抑制剂）或雷帕霉素（自噬增强剂）预处理。检测细胞活力、P-AKT1、T-AKT1、LC3 和 BECN1 的表达。通过血清转氨酶和炎症细胞因子、凋亡和组织学检查来衡量肝损伤的严重程度。GFP-LC3 重定位和透射电子显微镜用于检测自噬活性。H 2S 预处理激活了肝细胞中的 PtdIns3K-AKT1 信号通路。LY294002 可以消除 AKT1 的激活并减弱 H 2S 对肝细胞 A/R 和肝 I/R 损伤的保护作用。H 2S 在体外和体内均抑制肝自噬。进一步用 3MA 减少自噬也减弱了 H 2S 的保护作用，而雷帕霉素可以逆转自噬抑制作用并增强 H 2S 对肝细胞 A/R 和肝 I/R 损伤的保护作用。综上所述，H 2S 通过 AKT1 激活而不是自噬来保护肝细胞 A/R 和肝 I/R 损伤。自噬激动剂可以通过逆转 H 2S 的自噬抑制作用来增强这种肝保护作用。
