The Effect Of Zinc α2 Glycoprotein On Liver Glucose Metabolism And Insulin-related Signaling Pathways

Objective Cell transfection of Ad-ZAG was applied to upregulating the expression of ZAG in insulin resistant Hepa1-6 cells induced by palmitic acid(PA),and observed the changes of glucose metabolism and insulin signaling related proteins,to explore the role of ZAG in regulating glucose metabolism and insulin sensitivity.Methods1.Hepa1-6 cells were induced to a model of IR by being cultured to PA(0.4mmol/L)for 24 hours.2.Hepa1-6 cells were cultured in vitro.Ad-ZAG and empty vector were transfected into Hepa1-6 cells for 48 hours,then the cells were treated in serum-free conditions for 24 hours with PA at concentrations of 0.4mmol/L.Measuring the glucose consumption and western blot was used to detecting the protein level of ZAG、insulin signaling p-AKT、AKT 、 p-GSK3β 、 GSK3β and related genes involved in glucose metabolism(PEPCK、G6pase、Glut2).Results1.Hepa1-6 cells were cultured in PA(0.4mmol/L)for 24 hours,compared with Con group,the glucose consumption was decreased in the PA groups(p<0.05),indicating that a model of IR was successfully established in Hepa1-6 cells.2.With the intervention of PA,compared with Ad-GFP group,the protein level of ZAG was increased in Ad-ZAG group(p < 0.01),indicating that Ad-ZAG was transfected into Hepa1-6 cells successfully.3.With the intervention of PA,compared with Ad-GFP group,glucose consumption was significantly increased in Ad-ZAG group(p<0.05).Overexpressing of ZAG in Hepa1-6 cells,the protein level of p-AKT、p-GSK3β and GLUT2 were increased significantly(p<0.01),whereas the protein level of the key enzymes in gluconeogenesis(PEPCK and G6Pase)were significantly decreased(p<0.01).ConclusionIn vitro studies,with the intervention of PA,over-expression of ZAG could improve insulin resistance in Hepa1-6 cells by up-regulated the expression of p-AKT 、 p-GSK3β in insulin signaling and Glut2,down-regulated the expression of PEPCK and G6 Pase.Objective Tail vein injection of Ad-ZAG was applied to upregulating the expression of ZAG in insulin resistant mouse induced by high-fat diet,to explore the role of ZAG in regulating glucose metabolism and insulin sensitivity.MethodsMale C57BL/6J(n=16)mice aged 8 weeks were divided into Ad-GFP group(n=8)and Ad-ZAG group(n=8).After adaptive feeding for one week,mice were free access to high-fat chow for 18 weeks,at the 16 th weeks,Ad-ZAG group mice were injected Ad-ZAG(2×109 vg per mouse)through tail vein,while the Ad-GFP group mice were injected Ad-GFP in same volume respectively.After one week,the function of pancreas was measured by intraperitoneal glucose tolerance test(IPGTT)and intraperitoneal insulin tolerance(IPITT).At the 18 th week,liver tissues of mice were collected after sacrificed.Western blot was used to detecting the protein level of ZAG、insulin signaling p-AKT、AKT、p-GSK3β、GSK3β and related genes involved in glucose metabolism(PEPCK、G6pase、Glut2).Results1.Compared with Ad-GFP group,the protein level of hepatic ZAG was increased in Ad-ZAG group(p<0.01),indicating that Ad-ZAG was transfected into C57BL/6J mouse successfully.2.Compared with Ad-GFP group,the corresponding area under the curve of IPGTT and IPITT were significantly increased in Ad-ZAG group(p<0.05).Overexpressing of ZAG in C57BL/6J mouse,the protein level of p-AKT、p-GSK3β and Glut2 were increased significantly(p<0.01),Whereas the protein level of the key enzymes in gluconeogenesis(PEPCK and G6Pase)were significantly decreased(p<0.01).ConclusionIn vivo experiments,over-expression of ZAG could improve insulin resistance in high-fat diet induced mouse by up-regulated the expression of p-AKT、p-GSK3β in insulin signaling and Glut2,down-regulated the expression of PEPCK and G6 Pase.