Histone deacetylase inhibitors attenuate P-algA1-induced cell proliferation and extracellular matrix synthesis in human renal mesangial cells in vitro

Aim: Aberrantly glycosylated IgA1 is a key factor in the pathogenesis of IgA nephropathy (IgAN). In this study we investigated the effects of aggregated IgA1 derived from IgAN patients (P-algA1) on human renal mesangial cells (HMCs) and the anti-proliferative and antifibrotic effects of histone deacetylase (HDAC) inhibitors in vitro. Methods: Three types of IgA1 were prepared, ie, N-IgA1 (IgA1 from healthy volunteers), P-IgA1 (IgA1 from IgAN patients), and P-algA1 (aggregated IgA1 from IgAN patients). The isolated IgA1 was heated for thermal polymerization. The proliferation of human renal mesangial cells (HMCs) were assessed using MU assay. The expression levels of relevant proteins were examined using immunoblotting assays or immunohistochemistry. Results: P-algA1 (25-250 mu g/mL) dose-dependently promoted the proliferation of HMCs, and markedly increased the protein levels of type I histone deacetylase (HDAC1, HDAC2 and HDAC8) in the cells. Both P-IgA1 and N-IgA1 were much weaker in stimulating cell proliferation and HDAC expression. P-algAl (50 mu g/mL) markedly increased the protein levels of Col1a1 and PAI-1, as well as pSmad2/3 and pStat3 in the cells. Pretreatment with the HDAC inhibitor trichostatin A (TSA, 250 nmol/L) or valproic acid (VPA, 400 mu g/mL) partially reversed P-algA1-induced cell proliferation and extracellular matrix synthesis in HMCs. Conclusion: P-algAl produces pro-proliferative and profibrotic actions in HMCs via upregulating the expression of HDACs, and subsequently activating TGF-beta/Smad2/3 and Jak2/Stat3 signaling pathways. Both VPA and TSA attenuate P-algA1-induced cell proliferation and fibrosis in HMCs.