Angiotensin Ⅱ -induced apoptosis of podocyte is meliorated by overexpression of nephrin via PI3K-Akt signaling pathway / 中华肾脏病杂志

ABSTRACT

ObjectiveTo evaluate the effects of Ang Ⅱ on apoptosis of podocytes and explore the signaling pathwayof nephrin in preventingAng Ⅱ-inducedpodocyte apoptosis.MethodsDifferentiated mouse podocytes were exposed to Ang Ⅱ at different concentrations for 18 h or at 10-8 mol/L for variable incubation times.Undifferentiated mouse pedocytes were transfected using lipofectamine 2000 with the pcDNA3.1-mNPHS1 plasmid and stably transfected cell lines were generated with G418 selection.In separated experiments,untransfected mouse podocytes (MPC) and stably transfected podocytes with pcDNA3.1-neo and PcDNA3.1-mNPHS1 were exposed toAng Ⅱ(10-8 mol/L) or LY294002(a selective Akt inhibitor,50 μmol/L) for indicated times.Apoptosis was evaluated by flow cytometry.The expression of nephrin was assessed by quantitative real-time PCR,immunofluorescence and Western blotting.The phosphorylation level of Akt was determined by Westem blotting.Results(1) AngⅡ promoted podocyte apoptosis in a dose-and time-dependentmanner. PretreatmentwithlosartansignificantlypreventedAngⅡ -induced apoptosis. (2) Nephfin mRNA and protein were obviously decreased in podocytes exposed to 10-8 mol/L Ang Ⅱ for at least 12 h than those in vehicle-treated cells (P＜0.05).(3) Ang Ⅱ exposure for more than 15 min inhibited the phosphorylation of AKT in MPC,which was dramatically reversed by pcDNA3.1-mNPHS1 transfection,but not by pcDNA3.1-neo transfection. (4) Podocyte apoptosis was promoted byLY294002. Conversely,Ang Ⅱ-induced podocyteapoptosis was significantly alleviated by pcDNA3.1-mNPHS1 transfection.ConclusionAng Ⅱinduces mouse podocyte apoptosis which is suppressed by overexpression of nephrin through PI3K-Akt signaling pathway.