Regulation Of LncRNA MEG3 On Degradation Of Extracellular Matrix In Osteoarthritis Chondrocytes And Its Mechanism

Background: Osteoarthritis(OA)is a degenerative arthritis disease caused by the destruction of articular cartilage and basic bone.It mainly manifests as joint pain and movement obstruction in the early stage,and often fails to perform normal activities due to the severe wear and tear of articular cartilage in the later stage,which causes a great burden to the family of patients and society.At present,OA is mainly treated by drugs and surgery.Drug treatment mainly includes the use of symptomatic drugs,disease-modifying drugs and cartilage protectants,while surgical treatment mostly uses arthroscopic surgery,osteotomy,joint replacement and arthrodesis.However,the molecular mechanism of OA pathogenesis is still not completely clear,its treatment still remains on analgesia and limited improvement of limb function.At present,it is believed that articular cartilage degeneration determines the development process of OA at a certain extent.Therefore,in-depth exploration of effective methods and molecular mechanisms to inhibit degenerative damage of articular cartilage,so as to effectively limit and alleviate the progress of OA,will be of great significance in the prevention and treatment of OA.Articular cartilage is mainly composed of chondrocytes and extracellular matrix(ECM).Chondrocytes are the only cells in articular cartilage and play an important role in the normal physiological function of articular cartilage.Long noncoding RNAs(lncRNAs)are small RNA molecules commonly found in eukaryotic organisms and play an important role in regulating various life activities.Recently,several studies have shown that lncRNAs are abnormally expressed in OA tissues and cells,and lncRNAs can play a regulatory role in chondrocyte proliferation,apoptosis and inflammatory response in OA by forming a targeted regulatory axis with miRNAs through the mechanism of endogenous competing endogenous RNA(ce RNA).Given that the specific pathogenesis of OA is still unclear,it is important to explore the relationship between lncRNA and OA.Objective: This study aims to investigate the differential expression of lncRNA MEG3 in normal and OA chondrocytes,and to study the specific molecular mechanism of lncRNA MEG3 in regualting IL-1?-induced chondrocyte injury,and provide a new theoretical basis for the prevention and treatment of OA.Methods:1.The articular chondrocytes of SD rats were isolated and treated with IL-1? to establish the model of OA in vitro.MTT,flow cytometry,q PCR and Western blot were used to detect cell viability,apoptosis,the expression of MMP-13,ADAMTS-5,COL2A1,MEG3 and miR-93,respectively.These were performed to validate the successful establishment of an in vitro model of OA and the differential expression of lncRNA MEG3 and miR-93 in OA;2.Cells were transfected with MEG3 overexpression/knockdown vectors,cell proliferation,apoptosis,and the expression levels of MMP-13,ADAMTS-5,COL2A1 m RNA and protein were detected by Ed U,flow cytometry,q PCR,Western blot assays,respectively,to explore the effect of lncRNA MEG3 on chondrocyte proliferation,apoptosis and ECM degradation in the course of OA;3.Cells were transfected with MEG3 overexpression/knockdown vectors and micro RNA-93 mimic/inhibitor,respectively,and the expression levels of MEG3,micro RNA-93 and TGFBR2 were detected by q PCR or Western blot,in order to verify that lncRNA MEG3 indirectly regulates the expression of TGFBR2 by interacting with miR-93 through ce RNA mechanism;4.Cells were transfected with MEG3 and miR-93 overexpression vectors,and proliferation,apoptosis,expression levels of TGFBR2,MMP-13,ADAMTS-5 and COL2A1,and expression localization of MMP-13 and COL2A1 were detected by Ed U,flow cytometry,q PCR,Western blot and immunofluorescence.It was allowed to further demonstrated whether lncRNA MEG3 regulated chondrocyte proliferation,apoptosis and ECM degradation in the course of OA through the miR-93/TGFBR2 signaling axis.Results:1.After IL-1? treatment,the chondrocytes' s viability was significantly decreased and its apoptosis rate was significantly increased.What more,the MMP-13 and ADAMTS-5 that in the IL-1? treated chondrocytes were high-upregulated with significant,while the COL2A1 was down-regulated.lncRNA MEG3 was significantly down-regulated and micro RNA-93 was up-regulated in chondrocytes;2.Upregulation of Lnc RNA MEG3 significantly inhibited the apoptosis of chondrocytes and ECM degradation,whereas downregulation of MEG3 had the opposite effect;3.lncRNA MEG3 inhibits the expression of micro RNA-93 and indirectly increases the level of TGFBR2,while micro RNA-93 inhibits the expression of MEG3 and TGFBR2;4.Overexpression of Mi R-93 partially reversed the inhibition of MEG3 up-regulation on chondrocyte apoptosis and ECM degradation.Conclusion: Lnc RNA MEG3 is lowly expressed in chondrocytes induced by IL-1? and acts as ce RNA of miR-93 to regulate the expression of TGFBR2,apoptosis of chondrocyte and degradation of ECM,which ultimately affects the occurrence and development of OA.We studied the interaction of MEG3 and miR-93 in OA and finally found the MEG3-miR-93-TGFBR2 regulatory network in the occurrence and development of OA at the first time.The results will help to a better understanding of OA and provide a new sight in clinical application.