MiR-423-5p inhibition alleviates podocyte apoptosis in membranous nephropathy by targeting WT1/β-catenin axis

Membranous nephropathy (MN) is the most common pathological type of primary nephrotic syndrome in adults. MicroRNAs (miRNAs) are involved in the pathogenesis of several renal diseases. Here we investigated the potential involvement of miRNAs in MN progression.

miRNA sequencing was performed in the urinary exosomes of MN patients and normal controls (three cases per group). An experimental mouse MN model induced by cationic bovine serum albumin (CBSA) and MPC5 podocytes intoxicated by puromycin aminonucleoside (PAN) were used in this study.

Compared with the normal controls, 19 miRNAs were downregulated and 13 upregulated in the urinary exosomes of MN patients. In an expanded cohort, we confirmed that miR-423-5p was significantly upregulated in the urinary exosomes of MN patients. Urinary particle concentrations and size distribution were assessed using transmission electron microscopy and NanoSight. Similarly, upregulated miR-423-5p was observed in PAN-intoxicated MPC5 cells. Lentiviral vector-mediated inhibition of miR-423-5p suppressed podocyte apoptosis and inactivated β-catenin signaling. Upon miRNA database prediction, WT1 was identified as a target of miR-423-5p. Consistently, downregulated WT1 expression in PAN-intoxicated MPC5 cells was rescued by miR-423-5p inhibition. The target relationship between miR-423-5p and WT1 mRNA 3'UTR was validated by the dual luciferase reporter assay. Knockdown of WT1 reversed the inhibitory effect of LV-anti-miR-423-5p on podocyte apoptosis and β-catenin signaling. Notably, miR-423-5p inhibition and WT1 overexpression attenuated renal injury and podocyte apoptosis in MN mice.

Our study demonstrates that miR-423-5p expression is upregulated in urinary exosomes of MN patients and modulates WT1, affecting podocyte apoptosis by the β-catenin signaling pathway. Inhibition of miR-423-5p action may protect against MN.