Regulation Of Nr4a1 Expression Of Glomerular Cells Under Oxidative Stress To Improve Mesangial Cells Inflammatory Fibrosis

Objective: To explore the biological effects of Nr4a1 on glomerular mesangial cell inflammation and fibrosis under oxidative stress,and to provide scientific basis for alleviating glomerular fibrosis in diabetic nephropathy by investigating the relationship between Sirt1 and Nr4a1.Methods : 1.Under the condition of diabetic nephropathy,the expression of inflammatory fibrosis factor in kidney tissue of C57/LB6 diabetic mice was detected by immunoconfocal method,and the expression of inflammatory fibrosis factor in glomerular mesangial cells under oxidative stress was detected by immunofluorescence method.2.Under oxidative stress,the levels of Sirt1,Nr4a1 and NF-kappa B in glomerular mesangial cell line(HBZY-1)were detected by fluorescence quantitative PCR,and the effects of Sirt1 on the expression of Nr4a1 were investigated by treating glomerular mesangial cells with NMN and Nr4a1 agonists and inhibitors respectively.3.The interaction between Sirt1 and Nr4a1 was detected by immunoprecipitation.Results: The expression of fibrosis factor alpha-SMA in glomeruli and renal capsules of wild type mice was very low.With the aggravation of diabetes mellitus,the expression of inflammatory factor NF-kappa B and fibrosis factor alpha-SMA in kidney tissue of mice increased significantly(P < 0.01),while the expression of Sirt1 decreased significantly.The expression of Sirt1 and Nr4a1 decreased significantly(P < 0.01)and the relative expression of NF-kappa B increased significantly(P < 0.01)in cultured mesangial cells under high concentration of glucose in vitro compared with low concentration glucose(LG)control group.The expression of Sirt1 and Nr4a1 increased significantly(P < 0.01)and the relative expression of NF-kappa B decreased significantly(P < 0.01)after NMN intervention.The same results were obtained by immunoblotting and immunofluorescence.Further studies using immunoprecipitation showed that there was a protein-protein interaction between Sirt1 and Nr4a1 at normal sugar concentration.Conclusions: 1.Inflammation(NF-kappa B)and fibrosis factor(alpha-sma)expression in glomerular cells and oxidative stress of diabetic mice increased,while the expressions of Sirt1 and Nr4a1 were inhibited.2.NMN could increase the expression of Sirt1 in glomerular mesangial cells,thereby promoting the expression of Nr4a1 and alleviating inflammatory fibrosis in DN kidney.3.Sirt1 can regulate the level of NF-kappa B through Nr4a1,thus alleviating glomerular inflammation and fibrosis.