MiR-7-5p Promotes Hepatic Stellate Cell Activation by Targeting Fibroblast Growth Factor Receptor 4.

Shuxia Tian,Min Chen,Yonglong Han,Bing Wang,Junming Chen,Haonan Shang

doi:10.1155/2020/5346573

Abstract

Aims Fibroblast growth factor receptor 4 (FGFR4) is a key mediator that protects the liver from chronic injury. MicroRNA-7 (miR-7) is a tumor suppressor and associated with lipid homeostasis in the liver. This study was designed to examine the role of the miR-7-5p/FGFR4 axis in liver fibrogenesis. Methods TargetScan was employed to predict microRNAs that targeted FGFR4 on the 3′-untranslated region (3′-UTR). miR-7-5p and FGFR4 expression in pathological liver tissues and LX-2 cells was determined using qRT-PCR and an immunoblotting assay. A dual-luciferase assay was conducted to validate the target prediction. A Cell Counting Lit-8 assay was performed to assess the proliferation ability of LX-2 cells. Hydroxyproline content in LX-2 cells was measured using a hydroxyproline assay. The expression of hepatic stellate cell (HSC) activation markers was examined using qRT-PCR and an immunoblotting assay. Results FGFR4 was a putative target of miR-7-5p. In LX-2 cells, miR-7-5p targeted FGFR4 by binding to 3′-UTR. FGFR4 was downregulated, but miR-7-5p was markedly enhanced in the liver samples as the degree of liver fibrosis rose. miR-7-5p was negatively associated with FGFR4 expression in liver tissues. The miR-7-5p inhibitor blocked the lipopolysaccharide-induced proliferation and activation of LX-2 cells, and FGFR4 overexpression inhibited LX-2 cell proliferation and activation triggered by miR-7-5p. Conclusion miR-7-5p promotes HSC proliferation and activation by downregulating FGFR4.

Highlights

Most types of chronic liver diseases lead to the accumulation of extracellular matrix proteins, such as collagen, which is the cause of liver fibrosis [1]
Our in silico analysis implicated that Fibroblast growth factor receptor 4 (FGFR4) was targeted by miR-7-5p, indicating that miR-7-5p might be involved in liver fibrosis
MiR-7-5p was markedly increased in severe fibrosis or cirrhosis samples compared to mild fibrosis samples and was more enhanced in cirrhosis samples compared with severe fibrosis samples

Summary

Introduction

Most types of chronic liver diseases lead to the accumulation of extracellular matrix proteins, such as collagen, which is the cause of liver fibrosis [1]. Activation of hepatic stellate cells (HSCs) is one step toward liver fibrosis. Deletion of FGFR4 and Fgf (murine orthologue of FGF19) leads to significant liver fibrosis compared with little mates [8], suggesting that the FGFR4/FGF19 axis has antifibrotic properties. A growing number of evidences suggest that miRNAs play essential roles in various human diseases, including liver diseases [10]. Accumulating evidences suggested that dysregulation of miRNAs is involved in the process of liver fibrosis as well as HSC activation [12, 13], such as miR-29 families [14], miR-199, miR-200 [15], and miR-34 [16]. We aimed to characterize miRNAs modulating FGFR4/FGF19 signaling to get to know the molecular mechanism of liver fibrogenesis. Our findings indicated a novel role for miR-7-5p in the modulation of FGFR4/FGF19 signaling

Materials and Methods

Results

Discussion