HRD1在肝脏糖异生中的作用

Effects of HRD1 expression in hepatic gluconeogenesis

目的观察羟甲基戊二酰辅酶A还原酶降解蛋白1(HRD1)在肝脏糖异生中的作用。方法采用Western blot法检测5只饥饿小鼠、4只高脂饮食小鼠、4只糖尿病小鼠及其分别对应的正常对照小鼠(5、4、4只)肝脏组织磷酸烯醇式丙酮酸羧激酶(PEPCK)和HRD1的表达。分别使用毛喉素0、5和20μmol/L处理人肝癌细胞株HepG2,Western blot检测其PEPCK和HRD1表达。用腺病毒感染HepG2细胞以过表达HRD1,用Western blot检测其PEPCK和真核翻译起始因子2α(eIF2α)的表达。结果与对照组比较,饥饿小鼠肝脏组织中PEPCK和HRD1蛋白表达升高(P<0.05)。与各自对照组比较,高脂饮食及糖尿病小鼠肝脏组织PEPCK蛋白表达升高,而HRD1蛋白表达降低(P<0.05)。随着毛喉素浓度增加,HepG2细胞PEPCK和HRD1蛋白表达增高(P<0.05)。HRD1过表达可降低PEPCK和eIF2α蛋白表达量(P<0.05)。结论肝脏糖异生过程中HRD1高表达,过表达的HRD1通过抑制eIF2α负反馈抑制肝脏糖异生。

Objective To observe the role of Hmg-CoA reductase degradation 1（HRD1）in hepatic gluconeogenesis.Methods The expressions of phosphoenolpyruvate carboxykinase（PEPCK）and HRD1 were detected by Western blot in the hepatic tissues of 5starved mice,4high-fat diet mice,4diabetic mice and their corresponding normal control mice（5,4,4 mice）and the human hepatocellular liver carcinoma cell line HepG2 cells treated with forskolin 0,5 and 20μmol/L,respectively.The expressions of PEPCK and eukaryotic translation initiation factor 2α（eIF2α）in HepG2 cells infected with adenovirus over-expressed HRD1 were detected by Western blot.Results Compared with the control group,the protein expressions of PEPCK and HRD1 in the liver tissues of starved mice were increased（P〈0.05）.Compared with the control group,the expression of PEPCK protein in the liver tissues of high fat diet and diabetic mice was increased,while the expression of HRD1 protein was decreased（P〈0.05）.The protein expressions of PEPCK and HRD1 were increased as the concentration of forskolin increased（P〈0.05）.HRD1 overexpression reduced the expressions of PEPCK and eIF2α（P〈0.05）.Conclusion HRD1 is highly expressed in hepatic gluconeogenesis process,in which HRD1 overexpression plays a negative feedback role through inhibiting eIF2αexpression.