Suppression of microRNA-29 expression by TGF-β1 promotes collagen expression and renal fibrosis

Abstract

Synthesis and deposition of extracellular matrix (ECM) within the glomerulus and interstitium characterizes renal fibrosis, but the mechanisms underlying this process are incompletely understood. The profibrotic cytokine TGF-β1 modulates the expression of certain microRNAs (miRNAs), suggesting that miRNAs may have a role in the pathogenesis of renal fibrosis. Here, we exposed proximal tubular cells, primary mesangial cells, and podocytes to TGF-β1 to examine its effect onmiRNAs and subsequent collagen synthesis. TGF-β1 reduced expression of the miR-29a/b/c/family, which targets collagen gene expression, and increased expression of ECMproteins. In both resting and TGF-β1-treated cells, ectopi..