Mechanism Underlying The Dysregulation Of Glucose And Lipid Metabolism In Type 2 Diabetic Mice Elicited By Hepatic Downexpression Of PES-1

Objective Type 2 diabetes dyslipidemia is a common complication which is characterized by changes in the quantity and mass of lipoproteins or manifests as disorder of lipoprotein metabolism.Its typical symptoms are high levels of triglycerides,low levels of HDL and a large number of small LDL particles in the serum.The further development of lipid metabolism disorders in type 2 diabetes will lead to the accumulation of lipids in blood vessels,affecting blood vessels and promoting the occurrence and development of atherosclerosis.Current research on glucose and lipid metabolism disorders in type 2diabetes mainly focus on the role of signaling pathways such as insulin and AMPK in de novo lipogenesis and the synthesis and secretion of VLDL and Chylomicron.However,cell nucleolus stress induced by energy supply shortage is also one of the core pathologies of type 2 diabetes.But relevant studies are rarely observed.Therefore,the objective of this study was to investigate effect of hepatocyte nucleolar stress on the downregulation of nucleolar protein PES-1 on glucose and lipid metabolism disorder in type 2 diabetes mellitus.Methods At age of 6 weeks,KKA~yMale mice and C57 mice received available diet and drinking water.The experimental environment was kept at a temperature of 20-26?,a relative humidity of 40-70%,and the light and darkness alternated for every 12 hours.After one week of adaptive feeding,KKA~y mice were induced with a high-fat diet for more than three weeks,and blood glucose was collected from the tail vein for blood glucose testing.The model was considered successful when fasting plasma glucose>11.1mmol/L was obtained for three consecutive days.T2DM KKA~y mice were randomly divided into the experimental group(PES-1 group)and the experimental control group(GFP group),and C57 mice were the normal control group.The PES-1group was injected with adenovirus HBAAV2/9-Hspa9 sh RNA2-GFP shrna2-gfpg and GFP group was injected with control adenovirus HBAAV2/9-GFP,both groups were raised for another four weeks.The weight,fasting blood glucose and diet of the mice were measured weekly.After 28 days,the three groups of mice were sacrificed after fasting for8h(n=8/group),and blood and liver tissues were collected to detect TC,TG levels and PES-1 protein expression.Cell experiment:Mc A-rh7777 rat hepatocellular carcinoma epithelial cells were accurately counted and cultured in a six-well plate after passage with an equal number of cells per well,which was divided into the experimental group(PES-1 group)and the control group(NC group),with 3 Wells in each group.After 24 hours,the experimental group was transfected with PES-1 si RNA and the control group with NC si RNA.After 72 hours,the four lipid terms(TC,TG,HDL-C and LDL-C)in cells and medium were detected,and the expression of cell proteins was detected by Western Blotting.Results In terms of glucose metabolism,the down-regulation of PES-1,compared with the normal group,elicited the significant rise of two key rate-limiting enzymes(pepck and G6Pase)which promoted gluconeogenesis,but did not affect the activities of its upstream proteins(AKT and FOXO1).After the expression of PES-1 in the liver of T2DM mice was restored,the blood glucose of KKA~y mice was significantly declined.With respect to lipid metabolism,on the one hand,the down-regulation of PES-1,compared to the normal group,abnormally increased the TG level,which could be restored to normal levels after the restoration of PES-1 expression in vivo.Correspondingly,SREBP1c and ACC activities relevant to triglyceride synthesis were increased at the protein expression level after downexpression of PES-1.On the other hand,the changes of PES-1 had no impact on the levels of TC,HDL-C,and LDL-C.At the protein level,down-regulation of PES-1 did not influence the expression level of the cholesterol synthesis protein HMGCS1.Conclusion:The down-regulation of PES-1 is related to glucose and lipid metabolism in type 2 diabetes.According to our current study,down-regulation of PES-1 may elicit abnormally elevated triglycerides,meanwhile prompt pepck and G6Pase expression,which advances gluconeogenesis.These findings may unveil a novel mechanism underlying the dysregulation of lipid metabolism disorders in type 2 diabetes and provide a new target for future clinical practice.