Orthopaedic Research Institute, Department of Orthopaedic Surgery, St. George Hospital, University of New South Wales, Sydney, Australia.
J Cell Biochem. 2010 Feb 1;109(2):406-16. doi: 10.1002/jcb.22412.
This study addresses the role of bone morphogenetic protein-7 (BMP-7) in chondrogenic and osteogenic differentiation of human bone marrow multipotent mesenchymal stromal cells (BM MSCs) in vitro. BM MSCs were expanded and differentiated in the presence or absence of BMP-7 in monolayer and three-dimensional cultures. After 3 days of stimulation, BMP-7 significantly inhibited MSC growth in expansion cultures. When supplemented in commonly used induction media for 7-21 days, BMP-7 facilitated both chondrogenic and osteogenic differentiation of MSCs. This was evident by specific gene and protein expression analyses using real-time PCR, Western blot, histological, and immunohistochemical staining. BMP-7 supplementation appeared to enhance upregulation of lineage-specific markers, such as type II and type IX collagens (COL2A1, COL9A1) in chondrogenic and secreted phosphoprotein 1 (SPP1), osteocalcin (BGLAP), and osterix (SP7) in osteogenic differentiation. BMP-7 in the presence of TGF-beta3 induced superior chondrocytic proteoglycan accumulation, type II collagen, and SOX9 protein expression in alginate and pellet cultures compared to either factor alone. BMP-7 increased alkaline phosphatase activity and dose-dependently accelerated calcium mineralization of osteogenic differentiated MSCs. The potential of BMP-7 to promote adipogenesis of MSCs was restricted under osteogenic conditions, despite upregulation of adipocyte gene expression. These data suggest that BMP-7 is not a singular lineage determinant, rather it promotes both chondrogenic and osteogenic differentiation of MSCs by co-ordinating with initial lineage-specific signals to accelerate cell fate determination. BMP-7 may be a useful enhancer of in vitro differentiation of BM MSCs for cell-based tissue repair.
本研究探讨了骨形态发生蛋白 7（BMP-7）在体外人骨髓间充质基质细胞（BM MSCs）的软骨和成骨分化中的作用。在单层和三维培养中，BM MSCs 在存在或不存在 BMP-7 的情况下进行扩增和分化。刺激 3 天后，BMP-7 显著抑制扩增培养中 MSC 的生长。当在常用的诱导培养基中补充 7-21 天时，BMP-7 促进 MSC 的软骨和成骨分化。这通过实时 PCR、Western blot、组织学和免疫组织化学染色的特定基因和蛋白表达分析得到证实。BMP-7 的补充似乎增强了谱系特异性标志物的上调，例如软骨形成中的 II 型和 IX 型胶原（COL2A1、COL9A1）和骨形成中的分泌磷蛋白 1（SPP1）、骨钙素（BGLAP）和骨形成蛋白 2（SP7）。与单独使用任一因子相比，BMP-7 与 TGF-β3 一起在藻酸盐和微球培养物中诱导更好的软骨细胞蛋白聚糖积累、II 型胶原和 SOX9 蛋白表达。BMP-7 增加碱性磷酸酶活性并呈剂量依赖性加速成骨分化的 MSC 钙盐矿化。尽管脂肪细胞基因表达上调，但在成骨条件下，BMP-7 促进 MSC 成脂分化的潜力受到限制。这些数据表明，BMP-7 不是单一的谱系决定因素，而是通过与初始谱系特异性信号协调促进 MSC 的软骨和成骨分化，从而加速细胞命运决定。BMP-7 可能是用于基于细胞的组织修复的 BM MSC 体外分化的有用增强剂。
