Exosome-Derived <i>microRNA</i>-<i>22</i> Ameliorates Pulmonary Fibrosis by Regulating Fibroblast-to-Myofibroblast Differentiation <i>in Vitro</i> and <i>in Vivo</i>

Abstract

BackgroundAlthough aberrant proliferation and activation of lung fibroblasts are implicated in the initiation and progression of idiopathic pulmonary fibrosis (IPF), the underlying mechanisms are not well characterized. Numerous microRNAs (miRNAs) have been implicated in this process; however, miRNAs derived from exosomes and their relevance to fibroblast-to-myofibroblast differentiation have not been fully elucidated. In this study, we aimed to identify exosome-derived miRNAs relevant to fibrosis development. MethodsWe profiled exosome-derived miRNAs expression in sera of C57BL/6 mice exhibiting bleomycin-induced pulmonary fibrosis by miRNA array analysis. After validating a selected miRNA by quantitative reverse-transcription polymerase chain reaction, its effect on fibroblastto-myofibroblast differentiation was investigated using human lung fibroblasts. Furthermore, we determined the role of the selected miRNA in an in-vivo pulmonary fibrosis model. ResultsMiRNA array analysis revealed that miR-22 expression was increased by up to 2 fold on day 7 after bleomycin treatment compared with that in vehicle-treated mice. In vitro, miR-22 transfection suppressed TGF-β1-induced α-SMA expression. This was mediated via the 3 inhibition of the ERK1/2 pathway. Baseline α-SMA expression was increased upon miR-22 inhibitor transfection. Furthermore, miR-22 negatively regulated connective tissue growth factor expression in the presence of TGF-β1. In vivo, administration of a miR-22 mimic on day 10 after bleomycin challenge ameliorated pulmonary fibrosis lesions accompanied by decreased α-SMA expression in the model mice. ConclusionsExosomal miR-22 modulates fibroblast-to-myofibroblast differentiation. The present study warrants further investigations to shed light on miR-22 as a novel therapeutic target for patients with IPF.

Extracellular Vesicles in Organ Fibrosis: Mechanisms, Therapies, and Diagnostics

“…Levels of serum exosomal miR-125a-5p were higher in patients with silicosis as compared to healthy controls [ 76 ]. Bleomycin-induced pulmonary fibrosis was associated with increased serum levels of exosomal miR-22 and fibrotic pathology was ameliorated with a miR-22 mimic due to its ability to inhibit TGF-β1-induced expression of αSMA or profibrotic cell communication network factor 2 ( CCN2 ; also known as connective tissue growth factor) in lung fibroblasts in vitro [ 77 ].…”

“…Suppression of miR-425 expression in lung fibroblasts led to their enhanced proliferation and production of collagens, suggesting that fibrotic pathways in ARDS are regulated by cellular or exosomal miR-425 [ 93 ]. EVs from serum of mice with bleomycin-induced pulmonary fibrosis contained increased levels of several miRs including miR-22 [ 77 ] and miR-16 [ 94 ]. Bleomycin-induced pulmonary fibrosis was attenuated by mimics of either miR-22 or miR-16 which, when tested on TGF-β-treated lung fibroblasts in vitro, caused suppressed expression of, respectively, αSMA and CCN2 [ 77 ] or rapamycin-insensitive companion of mechanistic target of rapamycin (mTOR) ( Rictor ) and secreted protein acidic and rich in cysteine ( Sparc ) [ 94 ].…”

Neutrophils Modulate Fibrogenesis in Chronic Pulmonary Diseases

“…In systemic sclerosis, a systemic fibrotic disease, neutrophil-derived exosomes inhibit the proliferation, and migration of human dermal microvascular endothelial cells via S100A8/A9 in neutrophils, this result indicates that exosomes from neutrophils prevent lung remodeling (64). In mice with bleomycin-induced pulmonary fibrosis, exosomes containing microRNA-22 can ameliorate pulmonary fibrosis by suppressing transforming growth factor (TGF)-β1-induced expression of α-smooth muscle actin (65). This contrary effect of exosomes in fibric diseases is mainly caused by the different functional components contained in the released exosomes.…”

Macrophage‐derived exosomes mediate silica‐induced pulmonary fibrosis by activating fibroblast in an endoplasmic reticulum stress‐dependent manner

“…15,16 For example, the secretion level of exosomes into bronchoalveolar lavage fluid (BALF) is increased in human and experimental lung fibrosis, and exosomes found in increased amounts function as carriers of protein/miRNA that contribute to idiopathic pulmonary fibrosis (IPF) pathogenesis. 17,18 However, the secretion and potential contribution of alveolar macrophage-derived exosomes in silicosis remain largely unexplored.…”