Plasma TNF-α Improves Glucose Homeostasis In Diabetic Mice Independent With TNFRs And The Relationship Between MicroRNA-320 And Insulin Resistance

Objective:(1)The aim of the first part of the study is to explore the functional role of TNF-α in the regulation of glucose homeostasis.(2)The aim of the second part of the study is to explore the the relationship between microRNA-320 and insulin resistance,and the functional role of microRNA-320 in the process of pioglitazone regulate insulin resistance.Methods:(1)①Glucose tolerant test(GTT)and insulin tolerant test(ITT)were carried out to evaluate glucose homeostasis in TNFR1 and TNFR2 double knockout(TNFR1 and TNFR2 DKO)mice.② Plasma TNF-α in TNFR1 and TNFR2 DKO mice were measured,and evaluate the relationship between plasma TNF-α and glucose homeostasis.③ We down-regulated the level of plasma TNF-α in TNFR1 and TNFR2 double knockout mice via AAV-shTNF-α injection,then detect the results of the GTT and ITT experiments.④ We up-regulated the level of plasma TNF-α in ob/ob mice via AAV-TNF-α injection,then detect the change of glucose homeostasis,confirmed the functional role of plasma TNF-α in glucose homeostasis,and explore the mechanism of it.(2)①Using 3T3-L1 adipose cell set a model of insulin resistance,to detect cell glucose intake by glucose oxidase method,and detect the expression level changes of microRNA-320;②treat insulin resistant adipose cells with different concentration of pioglitazone(1uM,10uM,50uM,100uM,150uM),then detect the expression level changes of microRNA-320 at different time points(12h,24h,48h,72h).Results:(1)①Insulin resistance was dramatically improved in TNFR1 and TNFR2 double knockout mice;②The circulated TNF-α was upregulated in TNFR1 and TNFR2 double knockout mice;③ The improvement of glucose homeostasis was suppressed when TNFR1 and TNFR2 DKO mice were administered AAV-shTNF-α;④ The over-expression of plasma TNF-α could improve the results of GTT and ITT in ob/ob mice.(2)①After the differentiation of 3T3-L1 cells,the glucose intake in 3T3-L1 cells were decreased,and the microRNA-320 expression in cells were increased significantly;②After pioglitazone treatment,the glucose intake in adipose cells were increased,and the microRNA-320 expression in cells were decreased significantly.Conclusion:(1)①TNFR1 和 TNFR2 double knockout improved glucose Homeostasis in diabetic Mice;② plasma TNF-α play a key role in the regulation of glucose metabolism;③ TNF-α supplies a benefit to reduce insulin resistance via a TNFRs-independent way in diabetic mice;④ TNFR1 and TNFR2 may not be the only receptors for TNF-α.(2)①The microRNA-320 expression in insulin resistant fat cells were increased;② pioglitazone treatment can decrease the expression of microRNA-320 expression in insulin resistant fat cells,microRNA-320 may be a potential treat target in the process of insulin resistance treatment.