QingShen granules activates mitophagy to suppress renal tubular epithelial-mesenchymal transition via the miR-23b-5p/Nrf2/PINK1 axis.

Renal fibrosis (RF) is a pivotal pathological process in chronic kidney disease (CKD), driven by tubular epithelial-mesenchymal transition (EMT). Although Qingshen Granules (QSG) demonstrate clinical efficacy against CKD, their anti-fibrotic mechanisms, particularly concerning mitophagy regulation, remains poorly defined. This study sought to determine if QSG alleviates renal fibrosis by modulating the miR-23b-5p/Nrf2/PINK1 axis, thereby activating mitophagy, and consequently suppressing renal tubular EMT. An adenine-induced rat renal fibrosis model and a TGF-β1-induced EMT model in NRK-52E cells were established and treated with QSG or QSG-containing serum, respectively. In vivo, adeno-associated virus was administered via tail vein injection to overexpress miR-23b-5p. Gain- and loss-of-function experiments were conducted in cells using miR-23b-5p mimic/inhibitor, Nrf2 overexpression plasmid, and siRNA. The evaluated parameters included renal function, renal histopathology, ultrastructure, mitochondrial membrane potential, oxidative stress levels, and the expression of relevant proteins and genes. QSG significantly improved renal function in the adenine-induced model rats, alleviated renal tubular injury and collagen deposition, and reversed the aberrant expression of EMT markers. Furthermore, QSG upregulated miR-23b-5p, inhibited Keap1, facilitated Nrf2 nuclear translocation, and thereby activated PINK1/Parkin-mediated mitophagy both in vivo and in vitro. Overexpression of miR-23b-5p mimicked the protective effects of QSG, whereas inhibition of miR-23b-5p or knockdown of Nrf2 significantly attenuated QSG's beneficial effects on mitophagy and EMT. QSG activates mitophagy via the miR-23b-5p/Nrf2/PINK1 axis, thereby inhibiting renal tubular EMT and fibrosis progression.