CircRNA_010383 acts as a sponge for miR-135a and its downregulated expression contributes to renal fibrosis in diabetic nephropathy

Abstract

Diabetic nephropathy (DN), a vascular complication of diabetes mellitus, is the leading cause of death in diabetic patients. The contribution of aberrantly expressed circRNAs to diabetic nephropathy <i>in vivo</i> is poorly understood. Integrated comparative circRNA microarray profiling was used to examine the expression of circRNAs in diabetic kidney of db/db mice. We found that circRNA_010383 expression was markedly downregulated in diabetic kidneys, mesangial cells and tubular epithelial cells cultured in high-glucose conditions. circRNA_010383 colocalized with microRNA-135a (miR-135a) and inhibited miR-135a function by directly binding to miR-135a. <i>In vitro,</i> the knockdown of circRNA_010383 promoted the accumulation of extracellular matrix (ECM) proteins <a></a><a>and </a>downregulated the expression of transient receptor potential cation channel, subfamily C, member (TRPC1), which is a target protein of miR-135a. Furthermore, <a></a><a>circRNA_010383 overexpression</a> effectively inhibited the high-glucose-induced accumulation of ECM and increased TRPC1 levels <i>in vitro</i>. More importantly, the kidney-target of circRNA_010383 overexpression inhibited <a></a><a>proteinuria</a> and renal fibrosis in db/db mice. Mechanistically, we identified that a loss of circRNA_010383 promoted proteinuria and renal fibrosis in DN by acting as a sponge for miRNA-135a. This study reveals that circRNA_010383 may be a novel therapeutic target for DN in the future.