Oleanolic acid attenuated diabetic mesangial cell injury by activation of autophagy via miRNA-142-5p/PTEN signaling

Oleanolic acid (OA), a potential drug for diabetic nephropathy (DN) treatment was found to downregulate the expression of microRNA (miR). The research aimed to investigate the effect of OA on autophagy mediated through miR-142-5p targeted PTEN signal. NRK-52E cells were cultured under normal or high glucose condition. DN model were induced by intravenous injection with streptozotocin (55 mg/kg). Renal fibrosis mice were detected by hematoxylin and eosin (HE) staining, Masson staining and immunohistochemistry assay. TargetScan and dual-luciferase reporter assay system was used to detect the target of miR-142-5p. Expression levels of microRNA and proteins were analyzed by real-time PCR and western blotting. Autophagy was decreased in the progression of renal fibrosis in diabetic nephropathy mice (in vivo) and in high glucose-induced NRK-52E cells (rat kidney epithelial cells) (in vitro) as the expression ofLC-3I and LC-3II (indicators of autophagy) were decreased mice MiR-142-5p was unregulated and PTEN was down-regulated in kidney mice and high glucose-induced NRK-52E cells. Targetscan prediction revealed that PTEN was a target of miR-142-5p. OA restricted HG-induced NRK-52E cell fibrosis through inhibition of miR-142-5p to promote PTEN expression and autophagy levels. To sum up, the research indicated that OA promoted autophagy through inhibition of PI3K/AKT/mTOR pathway. OA alleviated diabetic renal fibrosis by increasing autophagy through regulation of miR-142-5p/PTEN via PI3K/AKT/mTOR pathway in NRK-52E cells.