Contribution to the extended hepatectomy by the modulation of endoplasmic reticulum stress-induced cell death

阻断死亡受体诱导的线粒体凋亡通路不足以抑制肝脏缺血/再灌注损伤和胆汁淤积损伤。因此，在这些肝损伤中，我们主要关注内质网应激诱导的细胞凋亡途径，即所谓的第三凋亡途径。本研究旨在阐明内质网应激诱导的细胞凋亡信号通路在小鼠肝脏缺血再灌注和胆汁淤积损伤中的作用。C57BL6小鼠肝脏缺血90min后再灌流，造成肝脏缺血/再灌注损伤。结扎胆管造成C57BL6小鼠胆汁淤积性肝损伤。逆转录-聚合酶链式反应显示GADD153和GRP78在再灌注后即刻和12h的表达水平均显著升高。Western blotting显示再灌流3h后GADD153表达增强。再灌流12h后，GRP78和caspase-12的mRNA表达水平升高。胆管结扎后24小时，GRP78和GADD153在mRNA和蛋白水平的表达均升高。Western blotting和TUNEL法检测结果显示，两种模型的细胞凋亡细胞数均明显增加，而前天冬氨酸氨基转移酶-12的表达均明显减少。综上所述，本研究首次证明内质网应激诱导的GADD153参与了肝细胞再灌注损伤和梗阻性黄疸的细胞凋亡过程。然而，GADD153在这些肝损伤中的具体作用尚不清楚。现在，我们正在使用GADD153基因敲除小鼠进行额外的实验。

Blocking of death receptor-induced and mitochondrial apoptotic pathways is insufficient to inhibition of hepatic ischemia/reperfusion injury and cholestatic injury. Therefore, we focus on endoplasmic reticulum(ER) stress-induced apoptotic pathway, so-called third apoptotic pathway, in these liver injuries. Our aim of this study is to clarify the role of ER stress-induced apoptotic signaling pathway in mouse hepatic ischemia/reperfusion and cholestatic injury. Ischemia/reperfusion injury was induced by ischemia in 70% of the liver for 90 minutes followed by reperfusion in C57BL6 mice. Cholestatic liver injury was induced by ligation of the bile duct in C57BL6 mice. RT-PCR demonstrated the elevation of mRNA levels in GADD 153 immediately after reperfusion and in GRP78 12 hours after reperfusion. Western blotting showed the enhanced expression of GADD153 3 hours after reperfusion. The mRNA levels in GRP78 and caspase-12 were elevated 12 hours after reperfusion. The expression of GRP78 and GADD153 were elevated in both mRNA and protein levels 24 hours after bile duct-ligation. In both models, the decrease in procaspase-12 and the increase in the number of apoptotic cell death were shown by the Western blotting and TUNEL assay, respectively. In conclusion, this study is a first report showing that GADD153 induced by ER stress is involved in apoptosis in hepatic injury after reperfusion and obstructive jaundice. However, the specific role of GADD153 in these hepatic injuries is not clear. Now we are conducting the additional experiment using GADD153 knock out mice.