[Effect of CKIP-1 on hepatocyte apoptosis in nonalcoholic fatty liver disease].

Objective: To explore the effect and underlying mechanism of casein kinase 2 interacting protein-1 (CKIP-1) on hepatocyte apoptosis in nonalcoholic fatty liver disease (NAFLD). Methods: Experimental study. An NAFLD cell model was established by inducing human hepatoma cell line, HepG2 cells, with oleic acid (OA). Flag-CKIP-1 expression vector and shRNA-CKIP-1 were transfected into HepG2 cells. Flow cytometry was used to detect the effect of CKIP-1 on the activity and apoptosis of NAFLD hepatocytes. The levels of apoptosis-related proteins were detected by Western blot. CKIP-1 knockout mice in C57BL/6 back-ground were fed with either standard or high-fat diet for 8 weeks. Apoptosis-related signal proteins in NAFLD hepatocytes were detected by immunohistochemistry. Results: After CKIP-1 was transfected into HepG2 cells, the degree of OA induced cell liposis was significantly reduced (P<0.05). Annexin V-FITC/PI flow cytometry showed that CKIP-1 reduced the apoptosis of steatotic hepatocytes. Overexpression of CKIP-1 could significantly inhibit the expression of caspase-3 and caspase-9 and increase the expression of Bcl-2/Bax (P<0.05). Knockdown of CKIP-1 could increase the expression of caspase-3 and caspase-9 (P<0.05). CKIP-1 knockout could further increase the expression of caspase-3 and caspase-9 in NAFLD mice (P<0.01,P<0.05), and further decrease the expression of Bcl-2/Bax (P<0.05). Conclusion: CKIP-1 inhibited the apoptosis of steatotic hepatocytes by up-regulating the expression of apoptosis inhibitor gene, Bcl-2/Bax, and affecting the proteases, caspase-3 and caspase-9.目的： 观察酪蛋白激酶2相互作用蛋白-1（CKIP-1）对非酒精性脂肪性肝病（NAFLD）小鼠肝细胞凋亡的影响并探讨其相关机制。 方法： 实验研究。使用油酸（OA）制备NAFLD细胞模型。将Flag-CKIP-1表达载体以及shRNA-CKIP-1转染肝细胞，实现CKIP-1的异常表达。采用流式细胞术检测肝细胞凋亡水平。Western blot检测凋亡相关蛋白表达。构建CKIP-1敲除NAFLD小鼠模型，肝脏病理切片免疫组化检测凋亡相关信号蛋白表达。 结果： CKIP-1转染后，肝细胞脂肪变性的程度明显减轻。与OA组相比，OA+sh-CKIP-1组肝细胞凋亡率明显增加（P<0.01），而OA+CKIP-1组肝细胞凋亡率明显下降（P<0.05）。CKIP-1抑制NAFLD细胞模型中凋亡相关信号分子蛋白caspase-3和caspase-9的表达（P<0.05、P<0.01），同时增加Bcl-2/Bax的表达水平（P<0.05）。CKIP-1敲除增加NAFLD小鼠肝细胞凋亡相关信号caspase-3和caspase-9的表达（P<0.01，P<0.05），同时降低Bcl-2/Bax的表达（P<0.05）。 结论： CKIP-1通过上调Bcl-2/Bax凋亡开关，产生对蛋白酶caspase-3和caspase-9的影响，从而抑制肝细胞的凋亡，改善NAFLD细胞的脂肪变性程度。.