The Role Of FFA Deposited In The Hepatocytes In Hepatic Insulin Resistance Of Type 2 Diabetes Mellitus

Objective: This work aims to explore the effect of FFA deposited in hepatocytes on hepatic insulin resistance from clinical,molecular and cellular levels,and to provide new ideas for the diagnosis and treatment of type 2 diabetes mellitus(T2DM).Methods: 1.Subjects Collecting: This study selected patients with type 2 diabetes who were hospitalized in the department of endocrinology in the affiliated hospital of Nantong university during the period from December 2016 to December 2017,aged 30 to 70 years.After removing inappropriate cases according to the exclusion criteria,the eligible patients were divided into two groups in line with waist circumference: abdominal obesity group(case group)and non-abdominal obesity group(control group).Information collected included basic data,clinical test and check data,previous medical history and lifestyle.Analyze the correlation between abdominal obesity and diabetes.2.Model Establishing: In the DMEM medium without fetal bovine serum,HepG2 cells were stimulated with 0.25 mM palmitate(PA)for 24 h.Immunoprecipitation(IP)was used to detect the interaction between Prdx1 and GRP78.HepG2 cells were transfected by Flag-prdx1 plasmids or Flag plasmids,followed by PA-incubated.The interaction between flag-prdx1 and GRP78 was detected by IP.After Flag-Prdx1,Flag,si-Prdx1,si-CON transfection,we use Werstern blot and qRT-PCR to test the levels of p-AKT,p-GSK3?,GRP78,p-IRE1?,PEPCK,G6 Pase.Glucose uptake in the cells was detected by Glucose Colorimetric/Fluorescence Assay kit.We also analyzed the intracellular lipid accumulation utilizing Oil Red O staining.With the aid of SPSS 20.0 software for statistical analysis,P < 0.05 is statistically significance.Results: 108 cases were included in this study,with 54 cases in the abdominal obesity group(case group)and 54 cases in the non-abdominal obesity group(control group).Using single factor analysis,the comparison between the two groups shows that there is statistically significant difference.The number of hypertension patients in abdominal obesity group is more than those in non-abdominal obesity group.There is also significant difference between two groups in body weight?BMI?waist circumference?waist height ratio?fasting blood glucose,fasting insulin,fasting C-peptide,TG,HDL-C,and fatty liver.We investigate the relationship between Fasting plasma glucose and abdominal obesity related indicators(body weight,BMI,waist circumference,waist height ratio,TG,HDL – C,fatty liver)through Pearson correlation coefficient analysis.The results show that the fasting blood sugar and weight,waist height ratio,TG,fatty liver were positively correlated.Fasting blood glucose and abdominal obesity related factors were also brought into multiple linear regression model,and the conclusion was further proved that the fasting blood glucose increased along with weight,waist height ratio,TG and fatty liver.2.Endogeous immunoprecipitation experiment results display that Prdx1 can interact with GRP78 and Prdx1 is mainly colocalized with GRP78 in the cytoplasm under insulin resistance.We depleted Prdx1 in insulin-resistante HepG2 cells.Here we revealed that the protein levels of GRP78 is upregulated and p-IRE1? is downregulated,in addition to the increased phosphorylation of AKT and GSK3? in the insulin signaling pathway.Oil red O staining and glucose uptake assay reveale that Prdx1 overexpression may enhance lipid accumulation,gluconeogenesis and inhibit glucose uptake through ER stress.Interference of Prdx1 could reverse the effect of PA on lipid accumulation,hepatic glucose uptake and gluconeogenesis.Conclusion:The disturbance of blood glucose metabolism in abdominal obesity patients of type 2 diabetes is more serious than that of non-abdominal obesity patients.And one of the critical pathogenesis is lipid depositing in liver,which might activate Prdx1,aggravate endoplasmic reticulum stress,and promote the development of hepatic insulin resistance.