Wang Guo-Dong, Zhao Xiao-Wei, Zhang Yu-Ge, Kong Ying, Niu Shuai-Shuai, Ma Long-Fei, Zhang Yuan-Min
Qingdao University, Qingdao, Shandong 266000, P.R. China.
Department of Orthopaedics, The Affiliated Hospital of Jining Medical University, Jining, Shandong 272029, P.R. China.
Mol Med Rep. 2017 Jan;15(1):75-80. doi: 10.3892/mmr.2016.5981. Epub 2016 Dec 5.
Osteoarthritis (OA) is a common cause of functional deterioration in older adults, and altered chondrogenesis is the most common pathophysiological process involved in the development of OA. MicroRNA‑145 (miR‑145) has been shown to regulate chondrocyte homeostasis. However, the function of miR‑145 in OA remains to be elucidated. In the present study, the expression levels of miR‑145 were examined in cartilage specimens from 25 patients with knee OA using reverse transcription‑quantitative polymerase chain reaction analysis. The effects of miR‑145 on the proliferation and fibrosis of the C‑20/A4 and CH8 cell lines were also investigated using 3-(4,5-dimethylth-iazol-2-yl)-2,5-diphenyltetrazolium bromide and western blot assays in vitro. The results revealed that the expression of miR-145 was decreased in the OA cartilage tissues, compared with normal cartilage tissues. The overexpression of miR‑145 by transfection of cells with miR‑145 mimics significantly inhibited C‑20/A4 and CH8 cell proliferation and fibrosis. Furthermore, tumor necrosis factor receptor superfamily, member 11b (TNFRSF11B) was identified as a direct target of miR‑145 in chondrocytes, which was confirmed using a dual‑luciferase reporter assay. The expression level of TNFRSF11B was markedly upregulated in the patients with OA, and the ectopic expression of miR‑145 was capable of suppressing the expression of TNFRSF11B. In addition, the knock down of TNFRSF11B using specific small interfering RNA also inhibited the proliferation and fibrosis of C‑20/A4 and CH8 cells in vitro. These data provide the first evidence, to the best of our knowledge, to suggest the critical function of miR‑145 in regulating the expression of TNFRSF11B, which may have important implications on the regulation of chondrocyte proliferation and fibrosis in OA.
骨关节炎（OA）是老年人功能衰退的常见原因，软骨形成改变是OA发展过程中最常见的病理生理过程。微小RNA-145（miR-145）已被证明可调节软骨细胞的稳态。然而，miR-145在OA中的功能仍有待阐明。在本研究中，采用逆转录-定量聚合酶链反应分析检测了25例膝骨关节炎患者软骨标本中miR-145的表达水平。还使用3-（4,5-二甲基噻唑-2-基）-2,5-二苯基四氮唑溴盐和蛋白质印迹分析在体外研究了miR-145对C-20/A4和CH8细胞系增殖和纤维化的影响。结果显示，与正常软骨组织相比，OA软骨组织中miR-145的表达降低。用miR-145模拟物转染细胞使miR-145过表达，显著抑制了C-20/A4和CH8细胞的增殖和纤维化。此外，肿瘤坏死因子受体超家族成员11b（TNFRSF11B）被确定为软骨细胞中miR-145的直接靶点，这通过双荧光素酶报告基因检测得到了证实。OA患者中TNFRSF11B的表达水平明显上调，miR-145的异位表达能够抑制TNFRSF11B的表达。此外，使用特异性小干扰RNA敲低TNFRSF11B也在体外抑制了C-20/A4和CH8细胞的增殖和纤维化。据我们所知，这些数据首次提供了证据，表明miR-145在调节TNFRSF11B表达中起关键作用，这可能对OA中软骨细胞增殖和纤维化的调节具有重要意义。
