Promotion of hepatic stellate cell activation and liver fibrosis by microRNA-33a-5p through targeting the Dickkopf-1-mediated wingless-related integration site/beta-catenin pathway.

Abstract

Liver fibrosis occurs in response to chronic liver injury and is characterized by the production of excess extracellular matrix (ECM) proteins, largely by activated hepatic stellate cells (HSCs). Numerous studies have implicated micro-ribonucleic acids (miRNAs) in liver fibrosis, but the mechanisms remain unclear. Herein, HSC activation by miR-33a-5p during hepatic fibrosis was investigated. The miR-33a-5p was increased in the fibrotic mice and activated HSCs. AntagomiR-33a-5p inhibited HSC activation, proliferation, and migration in vitro, while simultaneously inducing apoptosis. The luciferase reporter assays indicated that the miR-33a-5p bound to the three prime untranslated region (3'UTR) of Dickkopf-1 (DKK1). Further investigation revealed that the miR-33a-5p targeted DKK1-modulated wingless-related integration site (Wnt)/β-catenin signaling directly to control hepatic fibrosis. Notably, the mice treated with antgomiR-33a-5p exhibited increased expression of DKK1 and reduced expression of fibrosis markers, along with reduced fibrosis. The RNA was isolated from activated and quiescent LX-2 cells and subsequently sequenced. Transcriptomic and bioinformatic analyses indicated strong downregulation of DKK1 during LX-2 cell activation. This paper presents the first demonstration of the miR-33a-5p-mediated modulation of liver fibrosis, with miR-33a-5p found to interact with DKK1, leading to regulation of Wnt/β-catenin signaling. The transcriptomic changes occurring during HSC activation were also defined. Overall, the findings suggest that both miR-33a-5p and DKK1 may be useful targets for treating liver fibrosis.