Exosomal hsa_circ_0125310 promotes cell proliferation and fibrosis in diabetic nephropathy via sponging miR-422a and targeting the IGF1R/p38 axis

Diabetic nephropathy (DN) is still on the rise worldwide, and millions of patients have to be treated through dialysis or transplant because of kidney failure caused by DN. Recent reports have highlighted circRNAs in the treatment of DN. Herein, we aimed to investigate the mechanism by which high glucose-induced exo-circ_0125310 promotes diabetic nephropathy progression. circ_0125310 is highly expressed in diabetic nephropathy and exosomes isolated from high glucose-induced mesangial cells (MCs). High glucose-induced exosomes promote the proliferation and fibrosis of MCs. However, results showed that the effects of exosomes on MCs can be reversed by the knockdown of circ_0125310. miR-422a, which targets IGF1R, was the direct target of circ_0125310. circ_0125310 regulated IGF1R/p38 axis by sponging miR-422a. Exo-circ_0125310 increased the luciferase activity of the WT-IGF1R reporter in the dual-luciferase reporter gene assays and upregulated the expression level of IGF1R and p38. Finally, in vivo research indicated that the overexpression of circ_0125310 promoted the diabetic nephropathy progression. Above results demonstrated that the high glucose-induced exo-circ_ 0125310 promoted cell proliferation and fibrosis in diabetic nephropathy via sponging miR-422a and targeting the IGF1R/p38 axis.