Zhuang Lin, Fan Ye, Lu Ling, Ding Wenbin, Ni Chuangye, Wang Xuehao, Zhang Feng, Rao Jianhua
Liver Transplantation Center of First Affiliated Hospital and Translational Medicine Research Center of Jiangning Hospital, Nanjing Medical University, China; Key Laboratory of Living Donor Liver Transplantation of Ministry of Public Health, Nanjing, Jiangsu Province, China.
Liver Transplantation Center of First Affiliated Hospital and Translational Medicine Research Center of Jiangning Hospital, Nanjing Medical University, China; Key Laboratory of Living Donor Liver Transplantation of Ministry of Public Health, Nanjing, Jiangsu Province, China.
Biochem Biophys Res Commun. 2016 May 13;473(4):966-972. doi: 10.1016/j.bbrc.2016.03.162. Epub 2016 Apr 1.
Ischemic preconditioning (IP) has been shown to protect hepatic tissue from liver ischemia-reperfusion injury (IRI). TGR5, as a new-type bile acid receptor, has been shown protective roles in several liver diseases. However, the relationship between TGR5 and IP is still unknown. This study investigated effects of IP on TGR5 as well as the roles of TGR5 on hepatic tissue lesions and apoptosis in liver IRI. We showed that TGR5 was significantly upregulated in liver tissues after IP. To further analyzed effects of the TGR5 on liver IRI, wild type and TGR5 knockout mice were used to establish the liver IRI model. IP effectively alleviated liver IRI, but TGR5 deficiency significantly neutralized IP-related liver protection, as evidenced by serum alanine aminotransferase levels, histological liver damage, hepatocellular apoptosis and cytokines expressions. In addition, molecules related to apoptosis were detected by Western Blot, which showed that activation of TGR5 by IP increased expression of Bcl-2, and inhibited expressions of IRAK4 and cleaved caspase-3, but TGR5 deficiency abolished IP-induced expressions of anti-apoptosis molecule. In vitro, effects of TGR5 on hepatocytes were further analyzed by TGR5 agonist (INT-777) and hypoxia/reoxygenation (H/R), which displayed that INT-777 markedly attenuated H/R-induced hepatocellular apoptosis. In conclusion, our study indicates that IP alleviates hepatocellular apoptosis, and reduces liver IRI through TGR5-mediated anti-apoptosis functions.
缺血预处理（IP）已被证明可保护肝组织免受肝脏缺血再灌注损伤（IRI）。TGR5作为一种新型胆汁酸受体，已被证明在几种肝脏疾病中具有保护作用。然而，TGR5与IP之间的关系仍不清楚。本研究调查了IP对TGR5的影响以及TGR5在肝脏IRI中对肝组织损伤和细胞凋亡的作用。我们发现IP后肝组织中TGR5显著上调。为了进一步分析TGR5对肝脏IRI的影响，使用野生型和TGR5基因敲除小鼠建立肝脏IRI模型。IP有效减轻了肝脏IRI，但TGR5缺乏显著抵消了IP相关的肝脏保护作用，血清丙氨酸转氨酶水平、肝脏组织学损伤、肝细胞凋亡和细胞因子表达均证明了这一点。此外，通过蛋白质免疫印迹法检测了与细胞凋亡相关的分子，结果显示IP激活TGR5可增加Bcl-2的表达，并抑制IRAK4和裂解的caspase-3的表达，但TGR5缺乏消除了IP诱导的抗凋亡分子的表达。在体外，通过TGR5激动剂（INT-777）和缺氧/复氧（H/R）进一步分析了TGR5对肝细胞的影响，结果显示INT-777显著减轻了H/R诱导的肝细胞凋亡。总之，我们的研究表明IP通过TGR5介导的抗凋亡功能减轻肝细胞凋亡并减少肝脏IRI。
