PAX2 regulates NRP-1 expression in renal tubular epithelial cellsto promote epithelial-to-mesenchymal transition and renal fibrosis

Abstract

To observe the expression of neuropilin-1 (NRP-1) induced by paired-box gene 2 (PAX2) during the process of epithelial-to-mesenchymal transition (EMT) and renal fibrosis in unilateral ureteral obstruction (UUO) model in rats, and explore the mechanism of EMT induced by PAX2. Methods: The recombinant lentivirus expression vector for PAX2 was constructed and transfected into rat normal renal tubular epithelial cell line (NRK52E). The experimental cells were divided into three groups: transfection group, empty vector group, and normal group. E-cadherin and α-SMA were detected by western blot and real-time PCR. Expression of NRP-1 was detected by western blot, real-time PCR, and immunofluorescence. Sixty male Wistar rats were randomly divided into two groups: the sham-operation group (n=30) underwent left ureteral dissection, the UUO group (n=30) underwent left ureteral ligation. Post-operation on days 3, 7, 14, 21 and 28, 6 rats from each of the groups were sacrificed and the obstructed kidneys were dissected out. The histopathological changes were observed by hematoxylin-eosin and Masson staining. E-cadherin and α-SMA were detected by western blot and immunohistochemistry. Expression of NRP-1 and PAX2 were determined by western blot, immunohistochemistry, and real-time PCR. Results: Expression of NRP-1 mRNA and protein and α-SMA protein increased (P<0.05) while E-cadherin protein expression decreased (P<0.05) in the transfection group as compared to the empty vector group in vitro. In the UUO group, fibrosis was obvious, and there was decreased expression of E-cadherin protein (P<0.05) and increased expression of α-SMA protein and NRP-1 mRNA and protein (P<0.05) in comparison to the sham group. Conclusion: NRP-1 maybe mediate PAX2-induced EMT in renal tubular epithelial cells and renal fibrosis.