Molecular mechanism of osteogenesis-induced osteogenesis

成骨诱导成骨的分子机制

• 批准号: 14370591
• 负责人: KAWASHIMA Hiroyuki
• 金额: $ 8.9万
• 依托单位: Niigata University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2002
• 资助国家: 日本
• 起止时间: 2002 至 2003
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-14370591/
• 关键词: Mechanical stress; Osteogenesis; Osteoblast differentiation; α-adaptin C; Periodontal ligament; Mineralization; Msx2; OPLL; OPLL

We have recently demonstrated mechanical stress (MS)-induced osteoblast differentiation and subsequent osteogenesis in vitro, and suggested that BMP-4 may act as an autocrine/paracrine factor in this process. We have also identified more than 100 genes that are either up-or down-regulated by MS. Alpha-adaptin C is one such gene and is known to play a role in endocytosis as one of the constituents of coated pits/vesicles. In situ hybridization and immunohistochemical studies demonstrated that mRNA as well as protein of α-adaptin C was induced as early as 3 hr under MS loading. The expression overlapped with that of BMP-4, suggesting that these cells eventually differentiate into osteoblasts. Electron microscopy demonstrated that coated pits/vesicles increased in those areas where cells, under MS, become strongly positive with α-adaptin C. In addition, potassium depletion, a manipulation known to block endocytosis, inhibited MS-induced osteoblast differentiation. These data strongly sugg … More est that α-adaptin C is involved in the MS-induced osteoblast differentiation via stimulating endocytosis of molecules such as EGF receptors. To further characterize genes involved in MS-induced osteogenesis, we also compared gene expression between osteoblasts and periodontal ligament (PDL) cells. Our working hypothesis was that PDL cells may be equipped with a mechanism by which calcification is suppressed, since the PDL never calcifies in vivo despite esposure to strong intermittent MS and despite their reported osteogenic potential. Indeed, murine cell line PDL-L2 (recently established by us) does not produce mineralized nodules in vitro without superphysiological amounts of BMP-2. We showed that Msx2, one of the genes which are much more abundant in PDL-L2 than in osteoblasts, is a key regulator that prevents PDL-L2 cells from trans-differentiating into osteoblasts. We also demonstrated that Msx2 expression is suppressed in a symptom-dependent manner in affected ligaments of patients with OPLL. We further showed that Msx2 prevents PDL-L2 cells from mineralization by suppressing Runx2 action through directly binding to Runx2 and recruiting HDAC1 complex. We also demonstrated that MS failed to mineralize PDL-L2 cells in vitro, whereas it enhanced mineralization. of osteoblasts. Less

我们最近已经证明了机械应力（MS）诱导的成骨细胞分化和随后的成骨细胞在体外，并建议，BMP-4可能作为一个自分泌/旁分泌因子在这个过程中。我们还确定了超过100个基因，无论是上调或下调MS。α-适应素C是这样的基因之一，并被称为发挥作用的内吞作用的包被坑/囊泡的成分之一。原位杂交和免疫组织化学研究表明，α-adaptin C的mRNA和蛋白在MS负荷下早在3小时就被诱导。与BMP-4的表达重叠，表明这些细胞最终分化为成骨细胞。电子显微镜显示，在MS下细胞与α-适应素C呈强阳性的那些区域，包被的小凹/囊泡增加。此外，钾耗竭，一个已知的操作，阻止内吞作用，抑制MS诱导的成骨细胞分化。这些数据有力地证明了 ...更多信息 认为α-adaptin C通过刺激EGF受体等分子的内吞作用参与MS诱导的成骨细胞分化。为了进一步表征参与MS诱导成骨的基因，我们还比较了成骨细胞和牙周膜（PDL）细胞之间的基因表达。我们的工作假设是PDL细胞可能具有抑制钙化的机制，因为PDL在体内从不钙化，尽管它易受强间歇性MS的影响，尽管它有成骨潜力。事实上，鼠细胞系PDL-L2（我们最近建立）不产生矿化结节在体外没有超生理量的BMP-2。我们发现Msx 2是PDL-L2中比成骨细胞中丰富得多的基因之一，是阻止PDL-L2细胞转分化成成骨细胞的关键调节因子。我们还证明，Msx 2的表达被抑制在OPLL患者的受影响的韧带中以一种依赖性的方式。我们进一步表明，Msx 2通过直接结合Runx 2和募集HDAC 1复合物来抑制Runx 2作用，从而防止PDL-L2细胞矿化。我们还证明MS未能在体外使PDL-L2细胞矿化，而它却增强了矿化。成骨细胞。少

项目成果

Shimomura, J et al.: "Tensile stress induces α-adaptin C production in mouse calvariae in organ culture -The possible involvement of endocytosis in mechanical Stress-induced osteoblasts differentiation."J.Cell.Physiol.. 195(3). 488-496 (2003)

Shimomura, J 等人：“拉伸应力诱导器官培养中小鼠颅盖产生 α-适应素 C - 内吞作用可能参与机械应力 - 成骨细胞分化。”J.Cell.Physiol.. 195(3) -。 496（2003）

吉澤 達也: "Homeobox protein Msx2 acts as a molecular-defense mechanism for preventing ossification in ligament fibroblasts"Mol.Cell.Biol.. (in press).

Tatsuya Yoshizawa：“同源盒蛋白 Msx2 作为一种分子防御机制，可防止韧带成纤维细胞骨化”Mol.Cell.Biol..（出版中）。

下村 淳子: "Tensile stree induces α-adaptin C production in mouse calvariaein and organ culture : Possible involvement of endocytosis in mechanical stress-stimulated osteoblast differentiation"J.Cell.Physiol.. 195・3. 488-496 (2003)

Junko Shimomura：“拉伸应力诱导小鼠颅骨和器官培养物中α-适应素C的产生：机械应力刺激的成骨细胞分化中可能涉及内吞作用”J.Cell.Physiol.. 195・3（2003）。

下村 淳子: "Tensile stress induced α-adaptin C production in mouse calvariae in organ culture -The possible involvement of endocytosis in mechanical stress-induced osteoblast defferentiation"J.Cell.Physiol.. (in press).

Junko Shimomura：“拉伸应力诱导器官培养中小鼠颅骨产生 α-适应素 C - 内吞作用可能参与机械应力诱导的成骨细胞分化”J.Cell.Physiol..（出版中）。

斎藤 宜則: "A cell line with characteristics of the periodontal ligament fibroblasts is negatively regulated for mineralization and Runx2/Cbfa1/Osf2 activity, part of which can be overcome by bone morphogenetic protein-2"J.Cell Sci.. 115・2. 4191-4200 (2002)

Yoshinori Saito：“具有牙周膜成纤维细胞特征的细胞系的矿化和 Runx2/Cbfa1/Osf2 活性受到负调节，骨形态发生蛋白 2 可以克服其中的一部分”J.Cell Sci.. 115・2 。 4191-4200 (2002)