Plasma Gelsolin Promotes Proliferation of Mesangial Cell in IgA Nephropathy.

BACKGROUND/AIMS: Plasma gelsolin (pGSN) is an actin-binding protein that plays a critical role in the pathogenesis of rheumatoid arthritis. However, whether pGSN is involved in other immunological diseases remains unknown. This study focused on the relationship between pGSN and immunoglobulin A (IgA) nephropathy (IgAN). METHODS: Two hundred patients with IgAN, 200 patients each with several other types of nephropathy and healthy controls (HCs) who underwent kidney biopsies between 2000 and 2014 were enrolled in the study. The Oxford classification system was used to predict the risk of disease progression. Serum and renal tissue were used to detect pGSN, and the correlations between pGSN and IgA, galactose-deficient IgA1 (Gd-IgA1), transforming growth factor beta1 (TGF-ß1), fibronectin (FN) content, clinical symptoms, and kidney function were analyzed. RESULTS: We found that the pGSN levels were significantly decreased in sera from IgAN patients compared to sera from patients with other forms of glomerular nephritis and HCs. Furthermore, the serum pGSN levels were negatively correlated with the serum IgA1, FN, and TGF-ß1 levels, and positively correlated with the estimated glomerular filtration rate. Conversely, the glomerular pGSN content was significantly elevated in the IgAN patients and was positively correlated with TGF-ß1 and FN levels. In renal tissue, the pGSN levels were significantly higher in IgAN patients with M1 and S1 compared to patients with M0 and S0 (p < 0.05). Meanwhile, pGSN promoted human mesangial cell (HMC) proliferation by facilitating cell mitosis in vitro. pGSN also promoted integrin α2ß1 expression in HMCs and enhanced the integrin α2ß1-pGSN interaction. CONCLUSION: Our study suggested that pGSN may play an important role in the development of IgAN by promoting the proliferation of mesangial cells and that serum and glomerular pGSN levels may be new markers for predicting IgAN progression and prognosis.