Effect Of Angiotensin â…¡ On Expression Of Mitochondrial Dynamics Protein Drp1and Mfn1in Human Proximal Tubular Cells

BackgroundDiabetic kidney disease(DKD) is the most common Diabetic microvascular complication, and it is the main cause of the end-stage renal disease (ESRD). In the pathogenesis of DKD,renal mitochondria damage become research focus in recent years. Recent observation indicate that hyperglycemia induces the change of renal cells mitochondria dynamic. Drpl and Mfnl mediates mitochondrial fission and fusion processes. The renin-angiotensin system (RAS) plays a central role in regulating physiologic and pathophysiologic processes in the kidney,and angiotensin Ⅱ(Ang Ⅱ) is the primary effector of this system. How does dynamin-like protein Drp1and Mfn1express in renal tissues of diabetic nephropathy and the relationship between angiotensin II and Drp1,Mfn1is still unclear.ObjectiveTo observe the expression of Drpl and Mfnl in the renal tissues of diabetes nephrosis patients;To study the effect of AngⅡ on expression of Drpl and Mfnl in hunman proximal tubular cells(HK-2).Methods1.17patients were enrolled into the study,they were diagnosed as DKD(n=10) or minimal changes disease(primary kidney disease,control group,n=7).Renal pathological changes were observed by HE,PASM and PAS staining.The expression of Drp1and Mfn1was tested by immunohistochemistry. Pearson correlation analysis detected the correlation between the Drp1, Mfn1and proteinuria, creatinine.2.Human proximal tubular cells were treated with different concentration of angiotensin Ⅱ(AngⅡ) to observe the effect of AngⅡ on the expression of Drp1and Mfn1by Real Time PCR and Western Blot.Then HK-2cells were treated with high concentration of AngⅡ to detect the expression of Drp1and Mfn1at different time by Western Blot and Real Time PCR.Results1、The renal pathological change of Patients with diabetic nephropathy:HE,PASM and PAS staining showed that there were many lesions in the kidney of DKD patients such as moderate to severe proliferation of mesangial matrix,nodular sclerosis,diffuse or segmental thickening of the basement membrane, tubular atrophy and compensatory expansion.Immunohistochemistry showed that the expression of Drpl was significantly up-regulated in DKD patients,however,Mfnl was down-regulated in DKD patients.(P<0.05).2、The expression of Drpl and Mfnl in HK-2cells induced by AngⅡ:Both expression of Drp1mRNA and protein increased remarkably in HK-2cells induced by angiotensin Ⅱ in a dose-dependent and time-dependent manner(P<0.01) compare with the control;However,Both expression of Mfnl mRNA and protein decreased remarkably in HK-2cells induced by angiotensin Ⅱ in a dose-dependent and time-dependent manner(P<0.01).Conclusion1、Expression of Drp1increases in the renal tissue of DKD patients, and Mfnl decreases in the DKD patients. Serum creatinine and proteinuria were both positively correlate with Drp1,but negatively correlate with Mfnl.2、Angll up-regulates the expression of Drp1but down-regulates the expression of Mfn1in human proximal tubular cells in a dose-dependent and time-dependent manner.