Jäger Marcus, Fischer Johannes, Dohrn Wiebke, Li Xinning, Ayers David C, Czibere Akos, Prall Wolf Christian, Lensing-Höhn Sabine, Krauspe Rüdiger
Research Laboratory for Regenerative Medicine and Biomaterials, Department of Orthopaedics, Heinrich-Heine University Medical School, Moorenstr. 5, D-40225 Düsseldorf, Germany.
J Orthop Res. 2008 Nov;26(11):1440-8. doi: 10.1002/jor.20565.
Dexamethasone/ascorbic acid/glycerolphosphate (DAG) and bone morphogenic protein (BMP)-2 are potent agents in cell proliferation and differentiation pathways. This study investigates the in vitro interactions between dexamethasone and BMP-2 for an osteoblastic differentiation of mesenchymal stem cells (MSCs). Bone marrow-derived human MSCs were cultured with DAG (group A), BMP-2 + DAG (group B), and DAG + BMP-2 combined with a porous collagen I/III scaffold (group C). RT-PCR, ELISA, immuncytochemical stainings and flow cytometry analysis served to evaluate the osteogenic-promoting potency of each of the above conditions in terms of cell morphology/viability, antigen presentation, and gene expression. DAG induced collagen I secretion from MSCs, which was further increased by the combination of DAG + BMP-2. In comparison, the collagen scaffold and the control samples showed no significant influence on collagen I secretion of MSCs. DAG stimulation of MSCs led also to a steady but not significant increase of BMP-2 level. A DAG and more, a DAG + BMP-2, stimulation increased the number of mesenchymal cells (CD105+/CD73+). All samples showed mRNA of ALP, osteopontin, Runx2, Twist 1 and 2, Notch-1/2, osteonectin, osteocalcin, BSP, and collagen-A1 after 28 days of in vitro culture. Culture media of all samples showed a decrease in Ca(2+) and PO(4) (2-) concentration, whereas a collagen-I-peak only occurred at day 28 in DAG- and DAG + BMP-2-stimulated bone marrow cells. In conclusion, BMP-2 enhances DAG-induced osteogenic differentiation in mesenchymal bone marrow cells. Both agents interact in various ways and can modify osteoblastic bone formation.
地塞米松/抗坏血酸/甘油磷酸酯（DAG）和骨形态发生蛋白（BMP）-2是细胞增殖和分化途径中的强效因子。本研究调查了地塞米松与BMP-2在间充质干细胞（MSC）成骨分化方面的体外相互作用。将人骨髓来源的MSC分别用DAG培养（A组）、BMP-2 + DAG培养（B组）以及DAG + BMP-2联合多孔I/III型胶原支架培养（C组）。采用逆转录聚合酶链反应（RT-PCR）、酶联免疫吸附测定（ELISA）、免疫细胞化学染色和流式细胞术分析，从细胞形态/活力、抗原呈递和基因表达方面评估上述每种条件下促进成骨的效力。DAG诱导MSC分泌I型胶原，DAG + BMP-2联合使用时其分泌进一步增加。相比之下，胶原支架和对照样本对MSC分泌I型胶原无显著影响。DAG刺激MSC也导致BMP-2水平稳定但不显著升高。DAG以及DAG + BMP-2刺激均增加了间充质细胞（CD105+/CD73+）的数量。体外培养28天后，所有样本均显示有碱性磷酸酶（ALP）、骨桥蛋白、Runx2、Twist 1和2、Notch-1/2、骨连接蛋白、骨钙素、骨涎蛋白（BSP）和胶原-A1的信使核糖核酸（mRNA）。所有样本的培养基中钙（Ca2+）和磷酸根（PO42-）浓度均降低，而仅在DAG和DAG + BMP-2刺激的骨髓细胞中，I型胶原在第28天出现峰值。总之，BMP-2增强了DAG诱导的间充质骨髓细胞成骨分化。这两种因子以多种方式相互作用，并可改变成骨细胞的骨形成。
