Paired box 2 induces epithelial-mesenchymal transition in normal renal tubular epithelial cells of rats

Epithelial-mesenchymal transition (EMT) is considered to be a crucial stage of renal fibrosis. Previous studies have indicated that paired box 2 (PAX2) affects renal fibrosis, likely by regulating EMT. Therefore, we examined whether PAX2 directly induces normal renal tubular EMT in vitro. Recombinant PAX2 plasmid was transfected into a renal tubular epithelial cell line (NRK52E) derived from normal rats. The optimal time-point was evaluated through fluorescence detection, western blotting and real-time polymerase chain reaction (PCR). Morphological alterations were examined using phase-contrast microscopy. At the optimal time-point of transfection, the expression of E-cadherin, alpha-smooth muscle actin (alpha-SMA), fibronectin and snail was analyzed by western blotting and real-time PCR. PAX2 expression in NRK52E cells transfected with PAX2 plasmid reached its peak at 72 h post-transfection. The transfected cells became elongated. PAX2 transfection induced a fibrotic phenotype of NRK52E cells with increased expression of a-SMA, fibronectin and snail as well as decreased expression of E-cadherin. The optimal time-point for transfection efficiency was 72 h. In conclusion, PAX2 induces renal tubular mesenchymal transition in vitro.