title: Down-regulation of microRNA-216b inhibits IL-1β-induced chondrocyte injury by up-regulation of Smad3.
abstract: Osteoarthritis (OA) is the most common type of joint disease, leading to a major cause of pain and disability. OA is characterized by the continuous degradation of articular cartilage, mainly resulting in an imbalance between synthesis and degradation of articular chondrocyte extracellular matrix (ECM). Aberrant miR-216b expression has been found in multiple cancers. However, the level of miR-216b in OA cartilage and its role in progression of this disease are still unknown. In the present study, the functional roles of miR-216b and its expression in OA tissues and interleukin-1β (IL-1β)-induced chondrocytes were examined. We found that the level of miR-216b was significantly higher and Smad3 expression was obviously lower in OA cartilage and IL-1β-induced chondrocytes than in normal tissues and cells. Furthermore, a bioinformatics analysis and luciferase reporter assay identified Smad3 as a direct target gene of miR-216b, and Smad3 expression was reduced by miR-216b overexpression at both the mRNA and protein levels. A functional analysis demonstrated that miR-216b down-regulation obviously alleviated the IL-1β-induced inhibition in cell proliferation, type II collagen, and aggrecan down-regulation and matrix metalloproteinase-13 (MMP-13) up-regulation, while miR-216b overexpression had the opposite effects. Knockdown of Smad3 by siRNA reversed the effects of the miR-216b inhibitor on cell proliferation, the expressions of type II collagen, aggrecan, and MMP-13. Our results suggested that miR-216b contributes to progression of OA by directly targeting Smad3, providing a potential therapeutic target for treatment of OA.
authors.affiliation: Department of Orthopaedic Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200092, People's Republic of China.
authors.forename: Jiye
authors.initials: J
authors.lastname: He
authors.affiliation: Department of Orthopaedic Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200092, People's Republic of China.
authors.forename: Jiahong
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Department of Orthopaedic Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200092, People's Republic of China wangdongliangxin@yeah.net.
authors.forename: Dongliang
authors.initials: D
authors.lastname: Wang
mesh_terms: D053674:Aggrecans / Q000276:immunology; D002358:Cartilage, Articular / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D002460:Cell Line; D019902:Chondrocytes / Q000276:immunology / Q000378:metabolism / Q000473:pathology*; D015536:Down-Regulation; D006801:Humans; D053583:Interleukin-1beta / Q000276:immunology*; D053509:Matrix Metalloproteinase 13 / Q000276:immunology; D035683:MicroRNAs / Q000235:genetics*; D010003:Osteoarthritis / Q000235:genetics* / Q000276:immunology / Q000473:pathology; D051900:Smad3 Protein / Q000235:genetics*; D015854:Up-Regulation
chemical_list: D053674:Aggrecans; D053583:Interleukin-1beta; C575482:MIRN216 microRNA, human; D035683:MicroRNAs; C497790:SMAD3 protein, human; D051900:Smad3 Protein; C507079:MMP13 protein, human; D053509:Matrix Metalloproteinase 13
keywords: Extracellular matrix; Interleukin-1 beta; Osteoarthritis; chondrocytes; microRNA-216b