Circ_0116061 regulated the proliferation, apoptosis, and inflammation of osteoarthritis chondrocytes through regulating the miR-200b-3p/SMURF2 axis

Wei Zheng,Yong Li,Guanhua Hou

doi:10.1186/s13018-021-02391-9

Abstract

BackgroundCircular RNA (circRNA) has been shown to be associated with osteoarthritis (OA) progression. Circ_0116061 has been found to be highly expressed in OA cartilage tissues, but its role and mechanism in OA progression remain unclear.MethodsExpression levels of circ_0116061, microRNA (miR)-200b-5p, and Smad ubiquitin regulatory factor 2 (SMURF2) were detected using quantitative real-time PCR. The proliferation and apoptosis of cells were measured using cell counting kit 8 (CCK8) assay, colony formation assay, and flow cytometry. Furthermore, the protein levels of proliferation-related marker, apoptosis-related markers, inflammatory factors, and SMURF2 were tested using western blot (WB) analysis. In addition, the interaction between miR-200b-3p and circ_0116061 or SMURF2 was examined using dual-luciferase reporter assay and biotin-labeled RNA pull-down assay.ResultsCirc_0116061 and SMURF2 were highly expressed, and miR-200b-3p was lowly expressed in OA cartilage tissues. Knockdown of circ_0116061 could promote the proliferation and inhibit the apoptosis and inflammation of OA chondrocytes. MiR-200b-3p could be sponged by circ_0116061, and its inhibitor could reverse the regulation of circ_0116061 silencing on the biological functions of OA chondrocytes. SMURF2 was a target of miR-200b-3p, and its expression was positively regulated by circ_0116061. Silencing of SMURF2 also could enhance the proliferation and suppress the apoptosis and inflammation of OA chondrocytes. Furthermore, the regulation of circ_0116061 silencing on the biological functions of OA chondrocytes also could be reversed by SMURF2 overexpression.ConclusionOur data showed that circ_0116061 might regulate the miR-200b-3p/SMURF2 axis to promote the progression of OA.

Highlights

Osteoarthritis (OA) is a chronic degenerative joint disease caused by articular cartilage degradation, subchondral bone sclerosis, osteophyte formation, synovial inflammation, meniscal degeneration, and inflammation and fibrosis of the infrapatellar fat pad [1,2,3,4,5]
Compared to the cartilage tissues of healthy controls, we found that circ_0116061 was notably enhanced (Fig. 1a), miR-200b-3p was significantly decreased (Fig. 1b), and Smad ubiquitin regulatory factor 2 (SMURF2) was markedly promoted (Fig. 1c) in the cartilage tissues of OA patients
The results of flow cytometry showed that the apoptosis rate of OA chondrocytes was obviously repressed in the presence of circ_0116061 silencing (Fig. 2d)

Summary

Introduction

Osteoarthritis (OA) is a chronic degenerative joint disease caused by articular cartilage degradation, subchondral bone sclerosis, osteophyte formation, synovial inflammation, meniscal degeneration, and inflammation and fibrosis of the infrapatellar fat pad [1,2,3,4,5]. Zhao et al used highthroughput sequencing to find that circ_0136474 was highly expressed in OA cartilage tissues, and confirmed that it could promote OA progression by inhibiting the proliferation and promoting apoptosis and inflammation of OA chondrocytes [15]. In their study, they screened that circ_0116061 was an upregulated circRNA in OA cartilage tissues [15]. Circ_ 0116061 has been found to be highly expressed in OA cartilage tissues, but its role and mechanism in OA progression remain unclear

Objectives

Methods

Results

Conclusion