Department of Orthopedic Surgery, Xin Hua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China.
Department of Pathology, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States.
Am J Physiol Cell Physiol. 2023 May 1;324(5):C1007-C1016. doi: 10.1152/ajpcell.00460.2022. Epub 2023 Mar 20.
MicroRNAs play a critical role in bone marrow mesenchymal stem cell (MSC) chondrogenesis and regulate the progression of joint regeneration in osteoarthritis. Our previous research confirmed that miR146a relieves osteoarthritis by modulating cartilage homeostasis. However, few studies have revealed the relationship between miR146a and the chondrogenesis of MSCs, and the exact mechanisms remain unclear. This study aimed to determine the function of miR146a in the chondrogenic differentiation of MSCs and the potential mechanisms involved. MiR146a expression increased during chondrogenesis. MiR146a knockout (KO) led to the increased chondrogenesis of MSCs compared to that in wild-type (WT) MSCs, whereas the overexpression of miR146a by mimics resulted in the decreased chondrogenesis of MSCs, as determined by the mRNA expression of collagen, type II, alpha 1 (COL2A1), aggrecan, cartilage oligomeric matrix protein (COMP), and matrix metallopeptidase 13 (MMP13). Furthermore, cartilage defects could be treated better when injected with spheres induced from miR146aKO MSCs than from WT MSCs, indicating that miR146a inhibits chondrogenesis in vivo. In addition, based on miRNA-mRNA prediction analysis and a dual-luciferase reporter assay, we observed that the deletion of miR146a led to the increased expression of Lsm11 during chondrogenesis and demonstrated that miR146a targeted Lsm11 by binding to its 3'-untranslated region (UTR) and inhibited its translation. The inhibition of Lsm11 by silencing RNA (siRNA) reversed the increased ability of chondrogenesis by knocking out miR146a both in vivo and in vitro, suggesting that miR146a inhibits chondrogenesis by directly inhibiting Lsm11 in MSCs, which may be a novel target for treating osteoarthritis.
微小 RNA 在骨髓间充质干细胞 (MSC) 软骨形成中发挥关键作用，并调节骨关节炎中关节再生的进展。我们之前的研究证实 miR146a 通过调节软骨稳态来缓解骨关节炎。然而，很少有研究揭示 miR146a 与 MSC 的软骨形成之间的关系，确切的机制仍不清楚。本研究旨在确定 miR146a 在 MSC 软骨分化中的功能及其涉及的潜在机制。miR146a 的表达在软骨形成过程中增加。与野生型 (WT) MSC 相比，miR146a 敲除 (KO) 导致 MSC 的软骨形成增加，而模拟物过表达 miR146a 导致 MSC 的软骨形成减少，这通过胶原、II 型、α 1 (COL2A1)、聚集蛋白、软骨寡聚基质蛋白 (COMP) 和基质金属蛋白酶 13 (MMP13) 的 mRNA 表达来确定。此外，当注射来自 miR146aKO MSC 的球体时，软骨缺陷可以得到更好的治疗，表明 miR146a 在体内抑制软骨形成。此外，基于 miRNA-mRNA 预测分析和双荧光素酶报告基因测定，我们观察到 miR146a 的缺失导致软骨形成过程中 Lsm11 的表达增加，并表明 miR146a 通过结合其 3'-非翻译区 (UTR) 靶向 Lsm11 并抑制其翻译。沉默 RNA (siRNA) 抑制 Lsm11 逆转了 miR146a 敲除在体内和体外均增加的软骨形成能力，表明 miR146a 通过直接抑制 MSC 中的 Lsm11 抑制软骨形成，这可能是治疗骨关节炎的新靶点。
