Effect of ERK signalling pathway and aldose reductase on the expression of fibronectin induced by transforming growth factor β1 in human mesangial cells / 中华肾脏病杂志

ABSTRACT

Objective To study the effect of ERK signalling pathway and aldose reduetase(AR)on the transforming growth factor-β1(TGF-β1)-induced expression of fibronectin (FN)in nondiabetic nephropathy. Methods Human mesangial cells(HMCs)were cultured and transfected with pCDNA3-AR and AR gene silencing with small interfering RNA(siRNA).The AR expression in the HMCs was examined by real-time PCR and Western blotting was used to detect the protein expression of AR and FN. Inhibitors of AR and ERK signalling pathway were co-cultured with HMCs, then TGF-β1 was added and Western blotting was used to analyze the protein expression of FN. Results The expression of AR, FN and p-ERK was up-regulated by TGF-β1. AR was increased by 1.8-fold, FN was increased by 1.9-fold (P＜0.05), and p-ERK was increased by 5.l-fold after stimulation with TGF-β1 (P＜0.01). HMCs transfected with AR showed stronger protein expression of FN, more than 3.6-fold in the protein level of FN was observed in HMCs (P＜0.05). The HMCs of knockdown AR gene by siRNA showed decreased expression of AR,FN and p-ERK, the level of AR mRNA in HMCs transfected with AR siRNA was 10% of the level in untransfected cells or cells transfected with control siRNA (P＜0.01). Transfection with AR siRNA attenuated TGF-β1-induced FN production, more than 70% decrease in the protein level of FN and p-ERK was observed in HMCs with AR-siRNA (P＜0.01). Conclusions AR can regulate the expression of FN with the stimulation of TGF-β1, as AR gene is one of the responsive genes of TGF-β1, which may be associated with the activation of ERK signalling pathways induced by TCF-β1.