MiR-130b-3p Modulates Epithelial-Mesenchymal Crosstalk in Lung Fibrosis by Targeting IGF-1

Shuhong Li,Dong Leng,Dianhua Jiang,Jing Geng,Huaping Dai,Xiaoxi Huang,Jiurong Liang,Xuefeng Xu,Dingyuan Jiang,Chen Wang,Qiang Ding

doi:10.1371/journal.pone.0150418

Abstract

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive and usually lethal fibrotic lung disease with largely unknown etiology and pathogenesis. Evidence suggests microRNAs (miRNA) contribute to pathogenesis of IPF. In this study, we sought to identify miRNA expression signatures and determine the role of miR-130b-3p in lung fibrosis. The miRNA expression profile of the lungs from patients with IPF and normal donors was determined by Affymetrix microarray, and transcriptome with Affymetrix array. The functions and signal pathways as well as miRNA-mRNA networks were established by bioinformatics analysis. Luciferase assays and ELISA were used to confirm the miRNA target gene. The effect of miRNA-transfected epithelium on fibroblast activities was assessed using a co-culture system. The fibroblast activities were determined by qRT-PCR, western blotting, Transwell and BrdU assays. Seven miRNAs were significantly decreased in IPF lungs, with miR-130b-3p being the highest in the miRNA-mRNA network. Insulin-like growth factor (IGF-1) was a target gene of miR-130b-3p in the epithelium. miR-130b-3p inhibition in the epithelium induced collagen I expression and enhanced the proliferation and migration ability of fibroblast in co-culture systems, which mimicked the functions of exogenous IGF-1 on fibroblasts. Neutralizing IGF-1 with an antibody significantly reduced the modulatory effects of miR-130b-3p inhibitor-transfected epithelium on the activation of fibroblasts. Our results show that miR-130b-3p was downregulated in IPF lungs. miR-130b-3p downregulation contributed to the activation of fibroblasts and the dysregulated epithelial-mesenchymal crosstalk by promoting IGF-1 secretion from lung epithelium, suggesting a key regulatory role for this miRNA in preventing lung fibrosis.

Highlights

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, irreversible, and usually lethal lung disease characterized by unknown causes and few treatment options[1]
The pathways predicted by Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis were mitogen activated protein kinase (MAPK), phosphatidyl inositol 3 kinase (PI3K)-AKT, extracellular matrix (ECM)-receptor interaction and adherens junction (Fig B in S1 File)
We focused on miR-130b-3p, one of the downregulated miRNAs, and found that miR-130b-3p played an important role in the epithelial-mesenchymal crosstalk. miR-130b-3p modulates fibroblast activities by directly targeting the 3’-untranslated regions (3’-UTR) of IGF-1 mRNA and downregulating IGF1 expression in epithelial cells

Summary

Introduction

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, irreversible, and usually lethal lung disease characterized by unknown causes and few treatment options[1]. Interactions between alveolar epithelial cells and fibroblasts can regulate lung development and homeostatic equilibrium. The abnormal epithelial-mesenchymal crosstalk will form a profibrotic milieu and hamper the normal alveolar wound-repair process. This is believed to play a central role in the pathogenesis of IPF[2,3,4]. The injured epithelium will launch a dialogue with lung mesenchyme and the interactions between epithelial cell and fibroblast will eventually create a vicious cycle[5]. Transforming growth factor beta-1 (TGF-β1)[6], connective tissue growth factor (CTGF)[7], keratinocyte growth factor (KGF)[8], prostaglandin (PG)E2[9], and H2O2[10] have been implicated in these interactions in α-smooth muscle actin (SMA) gene expression, basement membrane formation, fibroblast proliferation and epithelial apoptosis

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Results

Conclusion