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Functional analysis of the cells embedded in bone and cartilage matrices

嵌入骨和软骨基质中的细胞的功能分析

基本信息

批准号：
12470056
负责人：
NOMURA Shintaro
金额：
$ 8.26万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2001
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-12470056/
关键词：
osteocyte osteoblast osteopostin Bone remodeling Osteoclast Bone Matrix Mechanical stress Transgenic Mice メカニカルストレスプロモーター GFP 石灰化

项目摘要

Head Investigator found that osteocytes, the cell types that embedded in bone matrix, produce osteopontin abundantly when mechanical stress is loaded to bone tissue. Particularly, osteopontin expressing cells located in the pressure side. This result suggest the possibility that osteocyte play important role for bone resorption by producing osteopontin. To test this possibility, chemoattractant activity of osteopontin was determined by chamber experiment. The result obtained clearly demonstrated that osteopontin act as chemoattractant to osteoclast by interaction with integrin α_vβ_5. Furthermore, we tested the bone remodeling activity of osteopontin-deficient mice with the loading of mechanical stress. The absence of bone resorption to the loading of pressure force was observed in osteopontin nockout mice also demonstrate that osteopontin is a key molecule of bone remodeling. In addition, we identified the promoter region which sensitize mechanical stress by producing transgenic mice. Promoter region of osteopontin was joined with reporter gene and injected the DNA fragment into mouse fertilized egg. We detected GFP signal in osteocytes when mechanical stress loaded to bone. The result revealed the function of osteocytes as mechanosensor cells. In addition, we identified the promoter region of osteopontin which required for the expression in hypertrophic chondrocytes. Taken together, knockout mice and transgenic mice generated provide us a new insight for the functional analysis of the cells embedded in bone and cartilage matrix.

主要研究者发现，当机械应力加载到骨组织时，骨细胞（嵌入骨基质中的细胞类型）大量产生骨桥蛋白。特别是，骨桥蛋白表达细胞位于压力侧。提示骨细胞可能通过产生骨桥蛋白在骨吸收过程中发挥重要作用。为了验证这种可能性，骨桥蛋白的化学引诱活性测定室实验。结果表明，骨桥蛋白通过与整合素α_vβ_5相互作用而对破骨细胞起趋化作用。此外，我们还检测了骨桥蛋白缺陷小鼠在机械应力负荷下的骨重建活性。在骨桥蛋白敲除小鼠中观察到的压力负荷下骨吸收的缺失也证明骨桥蛋白是骨重建的关键分子。此外，我们通过转基因小鼠的生产，鉴定了机械应力敏感的启动子区域。将骨桥蛋白启动子区与报告基因连接，将其注射入小鼠受精卵。当机械应力加载到骨上时，我们检测到骨细胞中的GFP信号。结果表明，骨细胞具有力学敏感细胞的功能。此外，我们还鉴定了骨桥蛋白在肥大软骨细胞中表达所需的启动子区域。总之，基因敲除小鼠和转基因小鼠的产生为我们提供了一个新的见解嵌入在骨和软骨基质的细胞的功能分析。