Cheng Hongwei, Jiang Wei, Phillips Frank M, Haydon Rex C, Peng Ying, Zhou Lan, Luu Hue H, An Naili, Breyer Benjamin, Vanichakarn Pantila, Szatkowski Jan Paul, Park Jae Yoon, He Tong-Chuan
Department of Surgery, The University of Chicago Medical Center, Illinois, USA.
J Bone Joint Surg Am. 2003 Aug;85(8):1544-52. doi: 10.2106/00004623-200308000-00017.
Bone morphogenic proteins (BMPs) are known to promote osteogenesis, and clinical trials are currently underway to evaluate the ability of certain BMPs to promote fracture-healing and spinal fusion. The optimal BMPs to be used in different clinical applications have not been elucidated, and a comprehensive evaluation of the relative osteogenic activity of different BMPs is lacking.
To identify the BMPs that may possess the most osteoinductive activity, we analyzed the osteogenic activity of BMPs in mesenchymal progenitor and osteoblastic cells. Recombinant adenoviruses expressing fourteen human BMPs (BMP-2 to BMP-15) were constructed to infect pluripotent mesenchymal progenitor C3H10T1/2 cells, preosteoblastic C2C12 cells, and osteoblastic TE-85 cells. Osteogenic activity was determined by measuring the induction of alkaline phosphatase, osteocalcin, and matrix mineralization upon BMP stimulation.
BMP-2, 6, and 9 significantly induced alkaline phosphatase activity in pluripotential C3H10T1/2 cells, while BMP-2, 4, 6, 7, and 9 significantly induced alkaline phosphatase activity in preosteoblastic C2C12 cells. In TE-85 osteoblastic cells, most BMPs (except BMP-3 and 12) were able to induce alkaline phosphatase activity. The results of alkaline phosphatase histochemical staining assays were consistent with those of alkaline phosphatase colorimetric assays. Furthermore, BMP-2, 6, and 9 (as well as BMP-4 and, to a lesser extent, BMP-7) significantly induced osteocalcin expression in C3H10T1/2 cells. In C2C12 cells, osteocalcin expression was strongly induced by BMP-2, 4, 6, 7, and 9. Mineralized nodules were readily detected in C3H10T1/2 cells infected with BMP-2, 6, and 9 (and, to a lesser extent, those infected with BMP-4 and 7).
A comprehensive analysis of the osteogenic activity of fourteen types of BMPs in osteoblastic progenitor cells was conducted. Our results suggest an osteogenic hierarchical model in which BMP-2, 6, and 9 may play an important role in inducing osteoblast differentiation of mesenchymal stem cells. In contrast, most BMPs are able to stimulate osteogenesis in mature osteoblasts.
已知骨形态发生蛋白（BMPs）可促进骨生成，目前正在进行临床试验以评估某些BMPs促进骨折愈合和脊柱融合的能力。不同临床应用中最佳使用的BMPs尚未明确，且缺乏对不同BMPs相对成骨活性的综合评估。
为了鉴定可能具有最强骨诱导活性的BMPs，我们分析了BMPs在间充质祖细胞和成骨细胞中的成骨活性。构建了表达14种人BMPs（BMP-2至BMP-15）的重组腺病毒，用于感染多能间充质祖细胞C3H10T1/2、前成骨细胞C2C12和成熟成骨细胞TE-85。通过测量BMP刺激后碱性磷酸酶、骨钙素的诱导情况以及基质矿化来确定成骨活性。
BMP-2、6和9显著诱导多能C3H10T1/2细胞中的碱性磷酸酶活性，而BMP-2、4、6、7和9显著诱导前成骨细胞C2C12中的碱性磷酸酶活性。在TE-85成骨细胞中，大多数BMPs（除BMP-3和12外）能够诱导碱性磷酸酶活性。碱性磷酸酶组织化学染色分析结果与碱性磷酸酶比色分析结果一致。此外，BMP-2、6和9（以及BMP-4和在较小程度上的BMP-7）显著诱导C3H10T1/2细胞中的骨钙素表达。在C2C12细胞中，BMP-2、4、6、7和9强烈诱导骨钙素表达。在感染BMP-2、6和9的C3H10T1/2细胞中很容易检测到矿化结节（在较小程度上，感染BMP-4和7的细胞中也能检测到）。
对14种类型BMPs在成骨祖细胞中的成骨活性进行了综合分析。我们的结果表明存在一种成骨分级模型，其中BMP-2、6和9可能在诱导间充质干细胞向成骨细胞分化中起重要作用。相比之下，大多数BMPs能够刺激成熟成骨细胞中的骨生成。
