He Jiye, Zhang Jiahong, Wang Dongliang
Department of Orthopaedic Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200092, People's Republic of China.
Department of Orthopaedic Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200092, People's Republic of China
Biosci Rep. 2017 Apr 28;37(2). doi: 10.1042/BSR20160588. Print 2017 Apr 30.
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.
骨关节炎（OA）是最常见的关节疾病类型，是导致疼痛和残疾的主要原因。OA的特征是关节软骨持续退化，主要是由于关节软骨细胞外基质（ECM）的合成与降解失衡所致。在多种癌症中均发现了miR-216b的异常表达。然而，miR-216b在OA软骨中的水平及其在该疾病进展中的作用仍不清楚。在本研究中，检测了miR-216b在OA组织和白细胞介素-1β（IL-1β）诱导的软骨细胞中的功能作用及其表达情况。我们发现，与正常组织和细胞相比，OA软骨和IL-1β诱导的软骨细胞中miR-216b的水平显著更高，而Smad3的表达明显更低。此外，生物信息学分析和荧光素酶报告基因检测确定Smad3是miR-216b的直接靶基因，miR-216b过表达在mRNA和蛋白质水平均降低了Smad3的表达。功能分析表明，miR-216b下调明显减轻了IL-1β诱导的细胞增殖抑制、II型胶原蛋白和聚集蛋白聚糖下调以及基质金属蛋白酶-13（MMP-13）上调，而miR-216b过表达则产生相反的效果。通过小干扰RNA（siRNA）敲低Smad3可逆转miR-216b抑制剂对细胞增殖、II型胶原蛋白、聚集蛋白聚糖和MMP-13表达的影响。我们的结果表明，miR-216b通过直接靶向Smad3促进OA进展，为OA治疗提供了潜在的治疗靶点。
