hERG钾通道通过降低氧化应激改善肝细胞糖代谢

Human ether-α-go-go related gene channels improves glucose metabolism via antioxidative stress in HepG2 cells

目的研究hERG钾通道(human ether-α-go-go related gene channels)在肝细胞中与糖代谢的关系。方法用hERG钾通道过表达载体转染人类肝癌细胞系(liver hepatocellular carcinoma,HepG2)细胞,通过荧光定量PCR(real-time PCR,RTPCR)和蛋白印迹(Western blotting)法检测糖代谢、糖异生、氧化应激及还原型烟酰胺腺嘌呤二核苷酸磷酸(nicotinamide adenine dinucleotide 2'-phosphate,NADPH)相关亚基的表达。结果 hERG钾通道蛋白可在肝脏细胞中表达,将hERG钾通道过表达于HepG2细胞后,糖异生相关基因葡萄糖-6-磷酸激酶(glucose-6-phosphatase,G6Pase)表达显著降低,而磷酸烯醇式丙酮酸羧激酶(phosphoenolpyruvate carboxykinase,PEPCK)表达有降低。胰岛素表达相关基因葡萄糖转运蛋白2(glucose transporter type 2,GLUT2)、胰岛素受体底物2(insulin receptor substrate,IRS-2)和腺苷酸活化蛋白激酶α亚基2[(adenosine 5’-monophosphate(AMP)-activated protein kinase),AMPKα2]的表达水平均显著增高。NADPH4种亚基p22、p47、p67和p91表达均显著降低。结论 hERG钾通道可以通过降低氧化应激改善肝细胞内糖代谢。

Objective To evaluate the effect of the new pathway of human ether-α-go-go related gene （hERG） channels on glucose metabolism in hepatic cells.Methods Liver hepatocellular carcinoma （HepG2） cells were transfected with hERG channels over-expression plasmid DNA.pcDNA3.1-GFP plasmid was used as a negative control.The expression of hERG,phosphoenolpyruvate carboxykinase（PEPCK） and glucose-6-phosphatase （G6Pase） were detected by Western blotting.The mRNA level of glucose transporter type 2 （GLUT2）,insulin receptor substrate （IRS-2）,adenosine 5＇-monophosphate（AMP）-activated protein kinase （AMPKα2）,p22,p47,p67 and p91 were observed by real-time PCR（RT-PCR）.Results The experiments showed that hERG gene can be expressed in HepG2 cells.Over-expression of hERG gene in HepG2 cells could down-regulate the expression of PEPCK,G6Pase.while GLUT2,IRS-2,AMPKα2 genes were up-regulated.Over-expression of hERG gene also inhibited the relative mRNA level of p22,p47,p67and p91.Conclusion hERG channels could be involved in improving glucose metabolism via anti-oxidative effects.