LncRNA MEG3 Promotes Proliferation And Inhibits Apoptosis In Osteoarthritis Chondrocytes By MiR-361-5p/FOXO1 Axis

Background: Long non-coding RNAs(lnc RNA)have become key players in gene regulation.Maternally expressed gene 3(MEG3)is involved in the development of a variety of tumors,and its potential role in the development of osteoarthritis should be further studied.Objective:This study aimed to investigate the role of lnc RNA MEG3 and related molecular mechanisms in osteoarthritis(OA).Material and Methods: Cartilage tissues of OA patients and healthy volunteers were collected.After transfection with the appropriate construct,chondrocytes were classified into Blank,pc DNA3.1-NC,pc DNA3.1-MEG3,si-NC,si-MEG3,pc DNA3.1-NC + mimics NC,pc DNA3.1-MEG3 + mimics NC,pc DNA3.1-NC + mi R-361-5p mimics and pc DNA3.1-MEG3 + mi R-361-5p mimics groups.Quantitative real-time polymerase chain reaction(q RT-PCR)was used to detect the expression of MEG3,mi R-361-5p and forkhead-box class O(FOXO1).Bioinformatics on-line software was used to predicte the binding sites of lnc RNA MEG3 and mir-361-5p as well as mir-361-5p and FOXO1.Then luciferase reporter assay and RNA Immunoprecipitation(RIP)were performed to verify their targeted relationship.After that,cell proliferation and apoptosis were detected by CCK-8 assay and flow cytometry analysis,respectively.Western blot was used to detect the expression levels of cartilage matrix proteins,cell proliferation and apoptotic proteins.Finally,histological analysis and immunostaining were conducted in the OA rat model.Results: Expression of MEG3 and FOXO1 was significantly decreased in OA compared with the normal group,while the expression of mi R-361-5p was increased.Knockout of MEG3 can inhibit the proliferation and promote apoptosis of articular chondrocytes.Overexpression of MEG3 can promote the proliferation and inhibit apoptosis of articular cartilage.MEG3 can target mi R-361-5p and regulate the expression of mi R-361-5p.The expression of MEG3 was negatively correlated with mir-361-5p expression(r =-0.529,P = 0.0026).Overexpression of MEG3 inhibits the protein expression levels of MMP13,ADAMTS-5,and increases Collagen Ⅱand Aggrecan extracellular matrix degradation associated protein expression.Mi R-361-5p can target FOXO1 and regulate the expression of FOXO1.In addition,the expression of FOXO1 was significantly positively correlated with MEG3 expression(r = 0.7119,P < 0.001),while negatively correlated with mi R-361-5p expression(r =-0.4015,P = 0.0279).Mi R-361-5p mimics or interference of FOXO1 can partially eliminate the effect of overexpression of MEG3 on articular chondrocytes.Finally,functional analysis of the osteoarthritis in rat model showed that MEG3 could inhibit the degradation of cartilage matrix.Conclusion: MEG3 can contribute to cell proliferation and inhibit cell apoptosis and degradation of extracellular matrix(ECM)via regulating the mi R-361-5p/FOXO1 axis in OA chondrocytes.