Effects Of Irisin On Insulin Resistance Related Signaling Pathways In Human Umbilical Vein Endothelial Cells Induced By High Fat High Glucose

Objective:Patients with type 2 diabetes mellitus(T2DM)are susceptible to vascular complications,its pathomechanism is closely related with proinflammatory statement and insulin resistance in T2 DM.The new myokine irisin can improve insulin resisitance and inhibit inflammatory in T2 DM.Therefore,the aim of this study is to research the effects of irisin on the insulin pathway and inflammatory pathway in human umbilical vein endothelial cells which were cultured with high fat and high glucose.In addition,whether irisin can inhibit apoptosis and functional damage of endothelial cells induced by high fat and high glucose is also investigated.Methods:The human umbilical vein endothelial cells(HUVECs)were cultured in vitro with high fat and high glucose,and treated with different concentrations of irisin.Then the state of endothelial cells was observed under inverted microscope.Western blot technique was used to detect the effects of irisin on insulin receptor substrate-1(IRS-1),protein kinase B(Akt)and glucose transporter 4(GLUT4).Besides,the levels of interleukin-1(IL-1)and tumor necrosis factor alpha(TNF-?)in the supernatant of endothelial cells were tested by enzyme linked immunosorbent assay(ELISA)after irisin treatment.RT-PCR and Western blot were applied to determine the expression of mRNA and protein of signaling molecules and adhesion molecules in nuclear factor kappa B(NF-?B)pathway.At the same time,the apoptosis of endothelial cells was detected byflow cytometry,and the glucose consumption was measured by glucose oxidase method,the migration function of endothelial cells was assessed by endothelial cell scratch test.Results:The results showed that the level of IRS-1 phosphorylation and the expression of GLUT4 on cell membrane was decreased in the high fat and high glucose group,which indicated that the insulin pathway of HUVECs was damaged in the high lipid and high sugar environment.However,the phosphorylation level of Akt showed on change.IRS-1,Akt phosphorylation and GLUT4 protein levels on cell membrane were increased after irisin intervention,suggesting that irisin could protect the insulin pathway of HUVECs from high lipid and high sugar environment.Meanwhile,detection of cell glucose consumption showed that it was decreased in high fat and high glucose group,while in irisin group was increased.Further suggests that irisin can improve the insulin resistance of HUVECs.In addition,that the secretion of IL-1,TNF-? and intercellular cell adhesion molecule-1(ICAM-1),vascular cell adhesion molecule-1(VCAM-1),monocyte chemotactic protein-1(MCP-1)of endothelial cells in high fat and high glucose group increased,equally,the expression of inflammatory pathway signaling molecules NF-?Bp65 and inhibitor of NF-?B(I?B?)phosphorylation levels were elevated.In the irisin intervention group decreased inflammatory cytokines and adhesion molecules were found,and the levels of NF-?Bp65 and I?B? phosphorylation levels were also decreased,showing the intervention of irisin can inhibit the NF-?B signaling pathway and its downstream factors in endothelial cells to inhibit inflammation.The results of flow cytometry and endothelial cell scratch test showed that apoptosis of endothelial cells were decreased,the proliferation and the migration function of endothelial cells were significantly improved in the irisin intervention group compered with high fat high glucose group.Conclusion:Irisin can improve the insulin resistance of endothelial cells induced by high fat and high glucose,promote its glucose uptake stimulated by insulin.Moreover,irisin can inhibit inflammatory pathway and decrease secretion of its downstream factors in endothelial cells,besides,reduce apoptosis,promote proliferation and migration function of endothelial cells.