Abstract: Objective TTo investigate the targeted regulation of the Nrf2 pathway by miR-23b-5p in transdifferentiation of rat renal tubular epithelial NRK-52E cells induced by transforming growth factor β1 (TGF-β1) and the effect of Qingshen Granules-medicated serum for alleviating transdifferentiation of NRK-52E cells. Methods NRK-52E cells with TGF-β1-induced transdifferentiation were transfected with miR-23b-5p mimic, miR- 23b-5p inhibitor or the negative control (NC) siRNA and then treated with of Qingshen Granules-medicated serum. CCK8 assay was used to detectthe changes in viability of NRK-52E cells. The targeting relationship between miR-23b-5p and Nrf2 was verified using a dual luciferase reporter gene assay. The expressions of Nrf2, Keap1 and α- SMA mRNAs and proteins in the treated cells were detected with RT- qPCR and Western blotting, and ROS production in the cells was detected with flow cytometry. Results Transfection of NRK-52E cells with miR-23b-5p mimic significantly increased the expression of Nrf2 mRNA, while inhibition of miR-23b-5p obviously lowered Nrf2 mRNA in the cells. Rno-miR-23b-5p significantly down-regulated the luciferase activity of Rno-Nrf2-wt but not that of Rno-Nrf2-mu (P<0.05). Treatment with TGF-β1 significantly decreased the expressions of miR-23b-5p and Nrf2 and increased the expressions of Keap1, α-SMA and ROS in NRK-52E cells (P<0.05), and these changes were obviously ameliorated by treatment with 20% Qingshen Granules-medicated serum for 24 h. Transfection of the cells with miR-23b-mimic significantly decreased the expressions of Keap1, α-SMA and ROS (P<0.05), which were further decreased by treatment with the medicated serum (P<0.05). Conclusion Qingshen Granules-medicated serum reduces transdifferentiation of NRK-52E cells via miR-23b-5p-mediated activation of the Nrf2 pathway.

Key words: miR-23b-5p; Nrf2 signaling pathway; NRK-52E cells; epithelial-mesenchymal transition of renal tubular; Qingshen Granules