Effects of microRNA-146a on the proliferation and apoptosis of human osteoarthritis chondrocytes by targeting TRAF6 through the NF-κB signalling pathway.

Jun-Hua Zhong,Shu-Yi Yan,Shou-Mei Zhao,Rui-Xiang Bian,Yong-Bing Zhang,Cui-Fang Liu,Jing Li,Ning Liu

doi:10.1042/bsr20160578

Abstract

The present study aims to investigate the effects of miR-146a on the proliferation and apoptosis of human osteoarthritis (OA) chondrocytes by targeting tumour necrosis factor receptor-associated factor 6 (TRAF6) through nuclear factor-κB (NF-κB) signalling pathway. Human normal and OA chondrocytes were selected and divided into the normal group, blank group, negative control (NC) group, miR-146a mimics group, miR-146a inhibitors, miR-146a inhibitor + si-TRAF6 group and si-TRAF6 group. Quantitative real-time PCR (qRT-PCR) was applied to detect the expressions of miR-146a, TRAF6 mRNA and NF-κB mRNA. Western blotting was used to detect the protein expressions of TRAF6 and NF-κB. CCK-8 assay and flow cytometry were used to detect cell proliferation and apoptosis. Compared with normal chondrocytes, the expression of miR-146a decreased, while the mRNA and protein expressions of TRAF6 and NF-κB increased in OA chondrocytes. OA chondrocytes had a lower proliferation rate and a higher apoptosis rate than the normal chondrocytes. Compared with the blank, NC and si-TRAF6 groups, the expression of miR-146a increased in the miR-146a mimics group, but decreased in the miR-146a inhibitors and miR-146a inhibitor + si-TRAF6 groups. Compared with the blank, NC and miR-146a inhibitor + si-TRAF6 groups, the mRNA and protein expressions of TRAF6 and NF-κB decreased, cell proliferation rate increased and cell apoptosis rate decreased in the miR-146a mimics and si-TRAF6 groups, while opposite trends were observed in the miR-146a inhibitors group. Our study suggests that miR-146a could promote proliferation and inhibit apoptosis of OA chondrocytes by inhibiting TRAF6 expression and suppressing the activation of NF-κB signalling pathway.

Highlights

Osteoarthritis (OA) is a degenerative disease in the joints, biochemically characterized by uncontrolled destruction of cartilage matrix, new bone formation at the joint margins, limited inflammation and changes in subchondral bone structure [1]
An experimental study demonstrated that the expression of miR-146a was lower in OA cartilage and its expression was induced by IL-1β stimulation [13]. miR-146a has a negative effect on inflammatory responses by suppressing cytokine-induced expression of interleukin-1 receptor-associated kinase-1 (IRAK1) and tumour necrosis factor receptor-associated factor 6 (TRAF6) via impairing nuclear factor-κB (NF-κB) activity and inhibiting the expression of target genes [10]
We found that the mRNA expression of TRAF6 and NF-κB decreased in the miR-146a mimics group while increased in the miR-146a inhibitors group

Summary

Introduction

Osteoarthritis (OA) is a degenerative disease in the joints, biochemically characterized by uncontrolled destruction of cartilage matrix, new bone formation at the joint margins (osteophytes), limited inflammation (synovitis) and changes in subchondral bone structure (sclerosis) [1]. MiRNAs are endogenous small non-coding RNAs (approximately 22 nts long), which can regulate gene expression post-transcriptionally and have been implicated in various diseases as c 2017 The Author(s) MiR-146a has a negative effect on inflammatory responses by suppressing cytokine-induced expression of interleukin-1 receptor-associated kinase-1 (IRAK1) and tumour necrosis factor receptor-associated factor 6 (TRAF6) via impairing nuclear factor-κB (NF-κB) activity and inhibiting the expression of target genes [10]. On this ground, we hypothesize that miR-146a may have correlations with TRAF6 and NF-κB signalling pathway in OA

Methods

Results

Discussion

Conclusion