Effect of Icariin Regulating mTOR/Akt/CREB Pathway on High Glucose Induced Autophagy and Apoptosis in Podocytes / 医药导报

ABSTRACT

Objective To investigate the effects of icariin on high glucose-induced autophagy and apoptosis of podocytes,and the regulating effects on mammalian target of rapamycin(mTOR)/serine-threonine kinase(Akt)/cyclic adenosine monophosphate response element binding protein(CREB)pathway.Methods The mouse podocytes MPC5 were taken and divided into five groups:normal control group(5.5 mmol·L-1 glucose),high glucose group(30 mmol·L-1 glucose),icariin group(30 mmol·L-1glucose+5 μmol·L-1icariin),GDC-0349 group(30 mmol·L-1glucose+50 μmol·L-1 GDC-0349),icariin+GDC-0349 group(30 mmol·L-1 glucose+5 μmol·L-1 icariin+50 μmol·L-1 GDC-0349).Cultured for 48 hours,the tetramethylazozolium salt method was used to detect the viability of MPC5 cells;acridine orange staining was used to observe the autophagy of MPC5 cells;apoptosis of MPC5 cells was detected by flow cytometry;Western blotting was used to detect the expression of autophagy[microtubule associated protein one light chain 3(LC3)II,LC3Ⅰ,autophagy-related protein(Beclin-1)],apoptosis[Bcl-2 related X protein(Bax),B cell lymphoma-2(Bcl-2)]and mTOR/Akt/CREB pathway-related proteins of MPC5 cells.Results Compared with the normal control group,the cell viability,expression levels of Bcl-2,phosphorylated mTOR(p-mTOR)/mTOR,phosphorylated Akt(p-Akt)/Akt,phosphorylated CREB(p-CREB)/CREB protein of MPC5 cells in the high glucose group were significantly decreased(P＜0.05),the autophagy ability was enhanced,the autophagosome showed orange fluorescence,and the apoptosis rate,LC3Ⅱ/LC3Ⅰ,Beclin-1,Bax protein expression levels were significantly increased(P＜0.05).Compared with the high glucose group,the cell viability,LC3Ⅱ/LC3Ⅰ,Beclin-1,Bcl-2,p-mTOR/mTOR,p-Akt/Akt,p-CREB/CREB protein expression levels of MPC5 cells in icariin group were significantly increased,the autophagy ability was further enhanced,the number of autophagosomes was increased,the autophagosomes showed brick red fluorescence(P＜0.05),the apoptosis rate and Bax protein expression level were significantly decreased(P＜0.05),and the cell viability,LC3Ⅱ/LC3Ⅰ,Beclin-1,Bcl-2,p-mTOR/mTOR,p-Akt/Akt and p-CREB/CREB proteins expression levels of MPC5 cells in GDC-0349 group were significantly decreased,the autophagy ability was weakened,the number of autophagosomes was reduced,the autophagosomes showed orange fluorescence(P＜0.05),and the apoptosis rate and Bax protein expression level were significantly increased(P＜0.05);icariin+GDC-0349 could reverse the effect of icariin on high glucose induced MPC5 cells(P＜0.05).Conclusion Icariin promotes elevated glucose-induced podocyte autophagy and inhibits apoptosis by activating the mTOR/Akt/CREB pathway.