Medical Research Center, The Affiliated Changzhou No. 2 People's Hospital of Nanjing Medical University, Changzhou, Jiangsu 213003, P.R. China.
Shenzhen Key Laboratory of Special Functional Materials, College of Materials, Shenzhen University, Shenzhen, Guangdong 518086, P.R. China.
Mol Med Rep. 2020 Nov;22(5):3904-3910. doi: 10.3892/mmr.2020.11487. Epub 2020 Sep 2.
Magnesium, an important inorganic mineral component in bones, enhances osteoblast adhesion and osteogenic gene expression. Mg2+‑containing hydroxyapatite promotes mouse mesenchymal stem cell (MMSC) osteogenic differentiation. In the present study, MMSCs were cultured in media containing different concentrations of MgCl2 (0 and 20 mM) for different time periods. Western blotting and reverse transcription‑quantitative PCR were performed to determine the expression levels of phosphorylated (p)‑p38 mitogen‑activated protein kinase (MAPK), the osteoblast‑specific transcription factor Osterix (Osx), runt‑related transcription factor 2 (Runx2), and p38 downstream genes, such as 27 kDa heat shock protein (hsp27), activating transcription factor 4 (Atf4), myocyte enhancer factor 2C (Mef2c) and CCAAT/enhancer‑binding protein homologous protein (Ddit3). The facilitatory effect of MgCl2 on MMSC osteogenic differentiation was assessed via Alizarin Red staining. The results suggested that MgCl2 increased p38 phosphorylation compared with the control group. Downstream genes of the p38 signaling pathway, including Osx and Runx2, as well as several osteogenesis‑associated downstream target genes, including Hsp27, Atf4, Ddit3 and Mef2c, were significantly upregulated in the Mg2+‑treated group compared with the control group. The increased osteogenic differentiation in the Mg2+‑treated group was significantly attenuated in MMSCs treated with SB203580, a specific inhibitor of the p38 signaling pathway. The results suggested that appropriate concentrations of MgCl2 promoted MMSC osteogenic differentiation via regulation of the p38/Osx/Runx2 signaling pathway.
镁是骨骼中一种重要的无机矿物成分，能增强成骨细胞黏附及成骨基因表达。含镁的羟基磷灰石能促进小鼠间充质干细胞（MMSC）的成骨分化。在本研究中，将 MMSC 分别培养于含不同浓度 MgCl2（0 和 20 mM）的培养基中不同时间。采用 Western blot 和逆转录-定量 PCR 法检测磷酸化 p38 丝裂原活化蛋白激酶（p38 MAPK）、成骨细胞特异性转录因子 Osterix（Osx）、成骨转录因子 2（Runx2）以及 p38 下游基因 27 kDa 热休克蛋白（hsp27）、激活转录因子 4（Atf4）、肌细胞增强因子 2C（Mef2c）和 CCAAT/增强子结合蛋白同源蛋白（DDIT3）的表达水平。通过茜素红染色评估 MgCl2 对 MMSC 成骨分化的促进作用。结果表明，MgCl2 能增加 p38 磷酸化。与对照组相比，p38 信号通路的下游基因 Osx 和 Runx2 以及多个与成骨相关的下游靶基因 hsp27、Atf4、DDIT3 和 Mef2c 在 Mg2+处理组中均显著上调。p38 信号通路的特异性抑制剂 SB203580 处理 MMSC 后，Mg2+处理组中增强的成骨分化作用明显减弱。结果表明，适当浓度的 MgCl2 通过调节 p38/Osx/Runx2 信号通路促进 MMSC 成骨分化。
