IgA1对人肾小球系膜细胞TGF-β_1、Smad7和纤连蛋白表达的影响

Effect of IgA1 on Expressions of TGF-β_1,Smad7 and Fibronectin Genes in Human Glomerular Mesangial Cell Line

目的:研究IgA1对人肾小球系膜细胞(HMCL)转化生长因子β1(TGF-β1)、Smad7和纤连蛋白(FN)表达的影响。方法:分别以正常人IgA1(NIgA1)、正常人聚合IgA1(aNIgA1)、IgA肾病(IgAN)患者IgA1(PIgA1)和IgAN患者聚合IgA1(aPIgA1)剌激体外培养的HMCL;RT-PCR法检测HMCL TGF-β1、Smad7和FN mRNA的表达,Western印迹法检测HMCL Smad7蛋白水平,ELISA法检测HMCL TGF-β1和FN蛋白水平。结果:PIgA1和aPIgA1能显著上调TGF-β1、Smad7F、N mRNA和蛋白的表达,且aPIgA1刺激组明显强于PIgA1刺激组(P<0.01或P<0.05)。在对照组、NIgA1刺激组和aNIgA1刺激组间,TGF-β1、Smad7、FN表达水平的差异无统计学意义(P>0.05)。在aPIgA1刺激HMCL不同时间组,TGF-β1、Smad7和FN表达水平逐渐升高,mRNA分别在12 h、12 h和24 h达高峰,蛋白水平分别在12 h2、4 h和24 h达高峰。结论:PIgA1和aPIgA1能上调HMCLTGF-β1、Smad7和FN的表达,aPIgA1的作用强于PIgA1,且呈一定的时间依赖性,提示IgAN患者血清IgA1,而且主要是aIgA1可通过影响TGF-β1、Smad7和FN而在IgAN进展中发挥作用。

Objective：To elucidate the role of IgA1 in mediating transforming growth factor （TGF） β1/Smads signaling pathway, the gene expressions of TGF-β1, Smad7 and fihronectin （FN） in human glomerular mesangial cell line （HMCL）. Methods：HMCL was cultured in 1 640 medium, stimulated with normal IgA1 （NIgA1）, aggregated normal IgA1 （aNIgA1）, IgA nephrotic （ IgAN） patient IgA1 （ PIgA1 ） and aggregated IgAN patient IgA1 （aPIgA1）, respectively, and the IgAl-free treatment as the control. The transcriptional levels of TGF-β1, p Smad7 and FN genes were semiquantitatively assayed by RT-PCR. The p-Smad7 protein was analyzed by Western blot; and the TGF-β1 and FN proteins were determined by ELISA. Results： PIgA1 and aPIgA1 significantly up regulated the expressions of TGF-β1 , Smad7 and FN genes, in which the levels of TGF-β1, Smad7, FN mRNA and TGF-β1 , Sinad7 proteins in aPIgA1 group were higher than that in PIgA1 group （P〈0.05 or P〈0. 01 ）, whereas,there was no significant difference of the three gene expression between the groups of NIgA1, aNIgA1 and the control. In the aPIgA1 group,the expressions of TGF-β1 , Smad7 and FN increased gradually, with the peaks for TGF-β1 , Smad7 and FN mRNA at 12 h, 12 h and 24 h,and for TGF-131 ,Smad7 and FN protein at 12 h, 24 h and 24 h, respectively. Conclusions ： PIgA1 and aPIgA1 but NIgA1 and aNIgA1 significantly up regulate TGF-β1 , Smad7, FN mRNA as well as their protein expressions in a time-dependent manner. It is suggested that serum IgA1, especially aIgA1 from IgAN patients, play an important role in progression of IgAN through TGF β1/Smads signaling pathway.