细胞外信号调节激酶信号通路与醛糖还原酶对转化生长因子β1诱导人系膜细胞纤连蛋白表达的影响

Effect of ERK signalling pathway and aldose reductase on the expression of fibronectin induced by transforming growth factor β1 in human mesangial cells

目的 探讨细胞外信号调节激酶（ERK）信号通路与醛糖还原酶（AR）在非高糖条件下对转化生长因子（TCF）β1诱导人系膜细胞（HMC）细胞外基质成分纤连蛋白（FN）表达的影响.方法 应用醛糖还原酶抑制剂（ARI）、ERK信号通路抑制剂U0126、转染pCDNA3-AR及AR-siRNA分别作用于HMC后,再用TGF-β1刺激,观察刺激前后HMC表达FN的情况.Western印迹检测HMC内FN和AR的变化,实时定量PCR鉴定转染和干扰效果.结果 HMC在TGF-β1作用后,AR、FN和磷酸化ERK（p-ERK）蛋白表达升高,与对照组比较,分别升高了1.8、1.9倍（均P＜0.05）和5.1倍（P＜0.01）.使用ARI孵育后,再用TGF-β1刺激,与单独使用TGF-β1刺激组比较,FN蛋白表达量约为对照组的30%（P＜0.01）;用ERK信号通路抑制剂后,再用TGF-β1刺激,FN蛋白表达量约为对照组的10%（P＜0.01）;转染pCDNA3-AR后,HMC中AR mRNA表达增多,为对照组10倍以上（P＜0.01）,FN蛋白表达增加到对照组的2.5倍（P＜0.05）,再用TGF-β1刺激,FN蛋白表达增加到对照组的3.6倍（P＜0.05）;转染AR-siRNA后,HNC中AR mRNA表达减少,干扰效率大于80%（P＜0.01）,AR、FN及p-ERK蛋白表达减少,分别约为对照组的20%、24%、7%（均P＜0.01）,再用TGF-β1刺激,FN蛋白表达仍然减少,为对照组的25%（P＜0.01）.结论 AR基因参与TGF-β1诱导的HMC细胞外基质表达过程的调控,在肾小球硬化过程中起一定作用,且这一过程与ERK信号通路的活化有关.

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.