Department of Joint Surgery & Sports Medicine, Qianfoshan Hospital of Shandong Province, Jinan, China.
Department of Orthopaedics, Liaocheng People's Hospital and Liaocheng Clinical School of Taishan Medical University, Liaocheng, China.
J Cell Biochem. 2019 Apr;120(4):5287-5303. doi: 10.1002/jcb.27803. Epub 2018 Oct 18.
microRNA (miR) has been shown to be involved in the treatment of diseases such as osteoarthritis (OA). This study aims to investigate the role of miR-206 in regulating insulin-like growth factor-1 (IGF-1) in chondrocyte autophagy and apoptosis in an OA rat model via the phosphoinositide 3-kinase (P13K)/protein kinase B (AKT)-mechanistic target of rapamycin (mTOR) signaling pathway. Wistar rats were used to establish the OA rat model, followed by the observation of histopathological changes, Mankin score, and the detection of IGF-1-positive expression and tissue apoptosis. The underlying regulatory mechanisms of miR-206 were analyzed in concert with treatment by an miR-206 mimic, an miR-206 inhibitor, or small interfering RNA against IGF-1 in chondrocytes isolated from OA rats. Then, the expression of miR-206, IGF-1, and related factors in the signaling pathway, cell cycle, and apoptosis, as well as inflammatory factors, were determined. Subsequently, chondrocyte proliferation, cell cycle distribution, apoptosis, autophagy, and autolysosome were measured. OA articular cartilage tissue exhibited a higher Mankin score, promoted cell apoptotic rate, increased expression of IGF-1, Beclin1, light chain 3 (LC3), Unc-51-like autophagy activating kinase 1 (ULK1), autophagy-related 5 (Atg5), caspase-3, and Bax, yet exhibited decreased expression of miR-206, P13K, AKT, mTOR, and Bcl-2. Besides, miR-206 downregulated the expression of IGF-1 and activated the P13K/AKT signaling pathway. Moreover, miR-206 overexpression and IGF-1 silencing inhibited the interleukins levels (IL-6, IL-17, and IL-18), cell apoptotic rate, the formation of autolysosome, and cell autophagy while promoting the expression of IL-1β and cell proliferation. The findings from our study provide a basis for the efficient treatment of OA by investigating the inhibitory effects of miR-206 on autophagy and apoptosis of articular cartilage in OA via activating the IGF-1-mediated PI3K/AKT-mTOR signaling pathway.
微小 RNA（miR）已被证明参与了骨关节炎（OA）等疾病的治疗。本研究旨在通过磷酸肌醇 3-激酶（PI3K）/蛋白激酶 B（AKT）-雷帕霉素靶蛋白（mTOR）信号通路，研究 miR-206 调节软骨细胞自噬和凋亡在 OA 大鼠模型中胰岛素样生长因子 1（IGF-1）的作用。使用 Wistar 大鼠建立 OA 大鼠模型，观察组织病理学变化、Mankin 评分以及 IGF-1 阳性表达和组织凋亡的检测。同时分析 miR-206 模拟物、miR-206 抑制剂或针对 OA 大鼠分离的软骨细胞中 IGF-1 的小干扰 RNA 处理后 miR-206 的潜在调节机制。然后，测定信号通路、细胞周期和细胞凋亡以及炎症因子中 miR-206、IGF-1 及其相关因子的表达。随后，测量软骨细胞增殖、细胞周期分布、凋亡、自噬和自噬溶酶体。OA 关节软骨组织 Mankin 评分较高，促进细胞凋亡率，IGF-1、Beclin1、轻链 3（LC3）、非典型蛋白激酶 1（ULK1）、自噬相关蛋白 5（Atg5）、胱天蛋白酶-3 和 Bax 表达增加，miR-206、PI3K、AKT、mTOR 和 Bcl-2 表达降低。此外，miR-206 下调 IGF-1 的表达并激活 PI3K/AKT 信号通路。此外，miR-206 过表达和 IGF-1 沉默抑制白细胞介素水平（IL-6、IL-17 和 IL-18）、细胞凋亡率、自噬溶酶体的形成和细胞自噬，同时促进 IL-1β 和细胞增殖的表达。本研究为通过激活 IGF-1 介导的 PI3K/AKT-mTOR 信号通路研究 miR-206 对 OA 关节软骨细胞自噬和凋亡的抑制作用，为 OA 的有效治疗提供了依据。
