MiR-146a alleviates lung injury caused by RSV infection in young rats by targeting TRAF-6 and regulating JNK/ERKMAPK signaling pathways

Zhi Huang,Xi Wu,Wenfeng Yu,Min Chen,Xiaoxian Liu

doi:10.1038/s41598-022-07346-6

Abstract

Respiratory syncytial virus (RSV) is a major cause of acute lower respiratory tract infection in infants and children. The present study aimed to investigate the effects of miR-146a on RSV replication and the related mechanisms. Material and methods: We pretreated A549 and HEp-2 cells and young rats with miR-146a mimic before infection with RSV. The expressions of miR-146a and RSV-F mRNA in cells and lung tissues were detected by RT-qPCR, and production of IL-1β, IL-6, IL-18, and TNF-α in bronchial alveolar lavage fluid (BALF) were determined by ELISA. The expression level of TRAF-6 and activation of the JNK/ERK/MAPK/NF-κB signaling pathway was detected by Western blotting. Results: RSV infection significantly reduced miR-146a levels in both A549 and HEp-2 cells and rat lung tissues. RSV infection resulted in accelerated growth, increased release of inflammatory cytokines, increased expression of TRAF-6, and activation of the JNK pathway in cells, and the lung inflammatory infiltration and the pathological score increased in rats. Overexpression of miR-146a targeted down-regulation of TRAF-6 expression and JNK/ERK/MAPK/NF-κB pathway induced by RSV infection, reduced the production of inflammatory cytokines IL-1β, IL-6 and TNF-α, and alleviate lung injury in young rats. We got similar results in both A549 and HEp-2 cell experiments. Conclusion: MiR-146a alleviates lung injury caused by RSV infection in young rats by targeting TRAF-6 and regulating JNK/ERK/MAPK signaling pathways.

Highlights

Human respiratory syncytial virus (RSV) is an encapsulated, negative single-stranded RNA virus, belonging to p neumonoviridae[1]
Respiratory syncytial virus (RSV) infection significantly increased the expression level of RSV-F mRNA in both A549 and Human epidermoid cell line type 2 cells (HEp-2) cells (P < 0.01), and transfection with miR-146a mimics effectively increased the expression level of miR-146a in the two kinds of cells compared with negative control transfection (P < 0.01, Fig. 1A,B)
RSV infection significantly decreased the growth of A549 cells and HEp-2 cells (P < 0.01), while increasing the growth inhibition rate (P < 0.01, Fig. 1C)

Summary

Introduction

Human respiratory syncytial virus (RSV) is an encapsulated, negative single-stranded RNA (ssRNA) virus, belonging to p neumonoviridae[1]. Other studies have confirmed the regulation of miRNA on RSV replication: microRNA-221 regulates RSV replication in human bronchial epithelium by targeting NGF expression[10]. The expression level of miR-146a was most significantly affected Both regulations of miR-146a expression and silencing of TNF receptor-associated factor-6 (TRAF-6) resulted in a significant reduction in stress-induced cytokine secretion, suggesting that miR-146a targets the potential role of TRAF-6 in airway inflammation. We infected young rats and cells with RSV virus respectively and upregulated miR-146a levels with miRNA mimics to explore the effects of miR-146a on lung injury of young rats and cell function, and attempted to explore its potential mechanism of action, providing new data support for the treatment strategy of RSV infection

Methods

Results

Conclusion