Influence of dexamethasone on the expression and distribution of transient receptor potential cation channel 6 in glomerular podocytes / 中华肾脏病杂志

ABSTRACT

Objective To observe the changes of foot processes,expression and distribution of transient receptor potential cation channel 6 (TRPC6) in podocytes by puromycin aminonucleoside (PAN) and dexamethasone (DEX) intervention,then to investigate the function of TRPC6 in podocytes and its relation to proteinuria in kidney diseases.Methods Podocytes cultured in vitro were divided into three groupcontrol group,PAN stimulation group and DEX intervention group.Mouse podocyte cell line (MPC5) were cultured in 0.02％ dimethyl sulfoxide (DMSO) in control group,subjected to PAN (50 μg/ml) treatment alone or with DEX (1 μmol/L) in other two groups for 8 h,24 h,48 h.The podocyte morphology was observed and took pictures by phase-contrast microscope,then the differences of morphology and areas were analyzed.The distribution,mRNA expression and protein expression of TRPC6 were detected by indirect immunocyto-fluorescence,real-time quantitative PCR and Western blotting,respectively.Results The well-developed podocyte arborization and interconnection was formed in control group,but PAN led to significant shrinkage of podocytes (P ＜ 0.05),together with podocyte foot process retraction,effacement and loss of cell contact.DEX significantly prevented the shrinkage and apoptosis of podocytes.The apoptosis rate was significantly increased after PAN stimulated 48 h (P ＜ 0.05).Real-time quantitative PCR and Western blotting found TRPC6 mRNA and protein expression were prone to increase in PAN group compared with control group (P ＜ 0.05).The distribution of TRPC6 becamed abnormal in PAN group.DEX decreased TRPC6 mRNA and protein expression at 48 h compared with PAN group (P ＜ 0.05).The abnormal distribution of TRPC6 was also alleviated by the protection of DEX.Conclusion DEX exerts a direct action to podocyte which retains the integrity of slit diaphragm against podocyte injury,and alleviates proteinuria via stabilizing mRNA,protein expression and distribution of TRPC6.