Effect of pirfenidone on the proliferation of human glomerular mesangial cells induced by serum IgA1 of IgA nephropathy patients / 中华肾脏病杂志

ABSTRACT

Objective:To investigate the effect of pirfenidone (PFD) on the proliferation of human glomerular mesangial cells (HMC) stimulated by serum IgA1 in patients with IgA nephropathy (IgAN) and its possible mechanism.Methods:Serum IgA1 of IgAN patients was purified by Jacalin affinity chromatography combined with Sephacryl S-200 gel filtration, and then heated to aggregated form (aIgA1). CCK8 method was used to confirm the concentration and time of PFD. The cells were divided into blank control group, IgA1 (0.5 mg/ml) group and IgA1 (0.5 mg/ml)+PFD (2 mmol/L) group. The CCK8 method was used to detect proliferation of mesangial cells. The cell cycle was detected by flow cytometry, and the proliferation index of mesangial cells was calculated. The expression levels of transforming growth factor β1 (TGF-β1), Smad4, Smad7, fibronectin (FN) and collagen Ⅳ protein and mRNA were detected through Western blotting and real-time PCR.Results:Compared with blank control group, the proliferation of HMC was promoted significantly by aIgA1 ( P<0.05). After PFD treatment, the proliferation of HMC was significantly inhibited ( P<0.01). Compared with the blank control group, the number of G1 phase cells decreased, the number of S phase cells and cell proliferation index increased in IgA1 group (all P<0.05). Compared with IgA1 group, the number of cells in G1 phase increased significantly, the number of cells in S phase and G2/M phase decreased significantly, and the cell proliferation index decreased in IgA1+PFD group (all P<0.05). Western blotting and real-time PCR results showed that compared with the blank control group, the protein and mRNA expressions of collagen Ⅳ, FN and Smad4 in HMC stimulated by aIgA1 were significantly increased, while TGF-β1 protein expression was increased and Smad7 protein expression was decreased (all P<0.05). After PFD treatment, the protein and mRNA expression of collagen Ⅳ, FN and Smad4 in HMC was significantly decreased, while TGF-β1 protein expression was obviously decreased, and Smad7 protein was up-regulated (all P<0.05). There was no significant difference in the mRNA expression of TGF-β1 and Smad7 in each group before and after PFD treatment (all P>0.05). Conclusions:PFD can increase the arrest of HMC in G1 phase, inhibit the proliferation of HMC induced by aIgA1 of IgAN patients, and reduce the production of extracellular matrix. The mechanism may be related to up-regulation of Smad7 expression and down-regulation of TGF-β1/Smad4 pathway.