Department of Orthopedics, The Second People's Hospital of Jingmen, Xiangshan Avenue 39#, Jingmen, 448000, Hubei, China.
J Mol Histol. 2022 Apr;53(2):285-296. doi: 10.1007/s10735-022-10067-9. Epub 2022 Mar 14.
Osteoarthritis (OA) is a slow-progressing degenerative joint disease mainly characterized by progressive cartilage loss and subchondral bone remodeling. Osteopontin (OPN) is a matrix extracellular glyco-phosphoprotein capable of regulating the expression levels of multiple factors linked with OA pathogenesis. This study explores the upstream regulatory molecular mechanism of OPN on proliferation and apoptosis of human chondrocytes in OA. Chondrocytes were isolated from OA cartilage and identified by toluidine blue staining and immunofluorescent staining of type II collagen. An MTT assay was used for cell viability, and a BrdU assay was applied for DNA synthesis. Cell apoptosis was detected by a flow cytometry assay. A lncRNA MIAT/miR-181a-5p/OPN axis regulating OA chondrocyte proliferation and apoptosis were identified. miR-181a-5p directly targeted OPN and inhibited OPN expression in OA chondrocytes. miR-181a-5p overexpression inhibited OA chondrocyte viability, suppressed DNA synthesis, and promoted apoptosis. OPN overexpression exerted opposite effects on OA chondrocytes and significantly attenuated the roles of miR-181a-5p overexpression in OA chondrocytes. A total of six long non-coding RNAs (lncRNAs) were predicted to target miR-181a-5p, and MIAT was the most up-regulated in OA cartilage tissues among the six lncRNAs. Through direct targeting, MIAT inhibited miR-181a-5p expression. MIAT silencing inhibited cell viability, suppressed DNA synthesis, and promoted cell apoptosis. Moreover, miR-181a-5p inhibition partially reversed the effects of MIAT silencing on OA chondrocytes. The lncRNA MIAT/miR-181a-5p/OPN axis could modulate OA chondrocyte proliferation and apoptosis. The comprehensive function of this axis on OA requires further in vivo and clinical investigations.
骨关节炎（OA）是一种缓慢进展的退行性关节疾病，主要特征为进行性软骨丧失和软骨下骨重塑。骨桥蛋白（OPN）是一种细胞外基质糖磷蛋白，能够调节与 OA 发病机制相关的多种因子的表达水平。本研究探讨了 OPN 在 OA 中对人软骨细胞增殖和凋亡的上游调控分子机制。从 OA 软骨中分离软骨细胞，通过甲苯胺蓝染色和 II 型胶原免疫荧光染色进行鉴定。MTT 法检测细胞活力，BrdU 法检测 DNA 合成。流式细胞术检测细胞凋亡。确定了 lncRNA MIAT/miR-181a-5p/OPN 轴调节 OA 软骨细胞增殖和凋亡的作用机制。miR-181a-5p 直接靶向 OPN，抑制 OA 软骨细胞中 OPN 的表达。miR-181a-5p 过表达抑制 OA 软骨细胞活力，抑制 DNA 合成，促进细胞凋亡。OPN 过表达对 OA 软骨细胞产生相反的作用，并显著减弱 miR-181a-5p 过表达对 OA 软骨细胞的作用。有 6 种长链非编码 RNA（lncRNA）被预测为靶向 miR-181a-5p，其中 MIAT 在 OA 软骨组织中是上调最明显的。通过直接靶向作用，MIAT 抑制 miR-181a-5p 的表达。MIAT 沉默抑制细胞活力，抑制 DNA 合成，促进细胞凋亡。此外，miR-181a-5p 抑制部分逆转了 MIAT 沉默对 OA 软骨细胞的作用。lncRNA MIAT/miR-181a-5p/OPN 轴可调节 OA 软骨细胞增殖和凋亡。该轴对 OA 的综合作用需要进一步的体内和临床研究。
