Department of Stomatology, The 4th Affiliated Hospital of China Medical University, No.4 Chongshan Dong Road, Shenyang, 110032, Liaoning, China.
Department of General Dentistry, School of Stomatology, China Medical University, Shenyang, 110001, Liaoning, China.
Stem Cell Res Ther. 2020 Dec 11;11(1):537. doi: 10.1186/s13287-020-02056-0.
The role of bone tissue engineering is to regenerate tissue using biomaterials and stem cell-based approaches. Combination of two or more cell types is one of the strategies to promote bone formation. Endothelial progenitor cells (EPCs) may enhance the osteogenic properties of mesenchymal stem cells (MSCs) and promote bone healing; this study aimed to investigate the possible mechanisms of EPCs on promoting osteogenic differentiation of MSCs.
MSCs and EPCs were isolated and co-cultured in Transwell chambers, the effects of EPCs on the regulation of MSC biological properties were investigated. Real-time PCR array, and western blotting were performed to explore possible signaling pathways involved in osteogenesis. The expression of osteogenesis markers and calcium nodule formation was quantified by qRT-PCR, western blotting, and Alizarin Red staining.
Results showed that MSCs exhibited greater alkaline phosphatase (ALP) activity and increased calcium mineral deposition significantly when co-cultured with EPCs. The mitogen-activated protein kinase (MAPK) signaling pathway was involved in this process. p38 gene expression and p38 protein phosphorylation levels showed significant upregulation in co-cultured MSCs. Silencing expression of p38 in co-cultured MSCs reduced osteogenic gene expression, protein synthesis, ALP activity, and calcium nodule formation.
These data suggest paracrine signaling from EPCs influences the biological function and promotes MSCs osteogenic differentiation. Activation of the p38MAPK pathway may be the key to enhancing MSCs osteogenic differentiation via indirect interactions with EPCs.
骨组织工程的作用是利用生物材料和基于干细胞的方法来再生组织。将两种或更多种细胞类型结合是促进骨形成的策略之一。内皮祖细胞（EPCs）可能增强间充质干细胞（MSCs）的成骨特性并促进骨愈合；本研究旨在探讨 EPCs 促进 MSC 成骨分化的可能机制。
分离和共培养 MSC 和 EPCs 在 Transwell 小室中，研究 EPCs 对 MSC 生物学特性调节的影响。进行实时 PCR 阵列和 Western blot 分析，以探讨参与成骨的可能信号通路。通过 qRT-PCR、Western blot 和茜素红染色定量检测成骨标志物的表达和钙结节形成。
结果表明，当与 EPCs 共培养时，MSCs 的碱性磷酸酶（ALP）活性显著增加，钙矿化沉积也明显增加。丝裂原活化蛋白激酶（MAPK）信号通路参与了这一过程。共培养的 MSC 中 p38 基因表达和 p38 蛋白磷酸化水平显著上调。在共培养的 MSC 中沉默 p38 的表达降低了成骨基因表达、蛋白合成、ALP 活性和钙结节形成。
这些数据表明 EPCs 的旁分泌信号影响 MSC 的生物学功能并促进其成骨分化。p38MAPK 通路的激活可能是通过与 EPCs 的间接相互作用增强 MSC 成骨分化的关键。
