权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

MECHANISM FOR BONE SIALOPROTEIN TO NUCLEATE BIOAPATITE

骨唾液酸蛋白使生物磷灰石成核的机制

基本信息

批准号：
6532972
负责人：
Ronald Joseph Midura
金额：
$ 18.49万
依托单位：
CLEVELAND CLINIC FOUNDATION
依托单位国家：
美国
项目类别：
财政年份：
1999
资助国家：
美国
起止时间：
1999-08-01 至 2003-07-31
项目状态：
已结题

项目摘要

Mineralization of bone is of critical importance to its numerous functions and can be perturbed in local or systemic musculoskeletal disorders. Our understanding of skeletal development, fracture healing, and bone remodeling will be enhanced by insights into the anabolic processes of bone matrix formation and biomineralization. There is considerable interest in the identification of biological molecules which nucleate bone mineral (bioaptite). This proposal hypothesizes that newly synthesized bone sialoprotein (BSP) nucleate bioapatite when associated with membrane- delimited vesicles. This hypothesis will be tested using natural periosteum and three osteoblastic culture models. We have observed spherical (sub)micron-sized apatite-containing particles ("bioapatite vesicles") in postnatal periosteum of rat tibia, as well as in primary and cell line osteoblastic cultures. They contain BSP and are strikingly similar in appearance to mineralized structures observed in osteoid ("crystal ghost aggregates"). Four aims are proposed addressing the structure/function relationship of BSP and apatite in "bioapatite vehicles". (1) Characterize the structure of bioapatite vehicles isolated from postnatal periosteum. (2) Spatially locate the major components of purified bioapatite vehicles in postnatal periosteum in situ. (3) Identify and structurally characterize any bioapatite vehicle counterparts from osteoblastic cultures. (4) Over-express BSP from an inducible gene construct transfected into osteoblastic cells. Aims 1 and 2 will provide a precise compositional database to compare the structure of bioapatite vehicles to that of matrix vesicles and crystal ghost aggregates. Aim 3 will identify relevant culture models to assess mechanisms of formation and determine essential molecular components. Aim 4 will directly test whether over-expression of BSP enhance apatite nucleation and whether it is a critical structural component for bioapatite vehicle integrity. This proposed research will yield new insight into apatite formation by osteoblasts because it will analyze a unique nucleation structure and ascertain the function of BSP in these entities. Ultimately, e believe that characterization of these novel biomineralization structures will lead to a better understanding of the mechanisms for bine mineralization and perhaps lead to new treatments to improve mineralization disorders of bone.

骨的矿化对其众多功能至关重要，并且可能在局部或全身肌肉骨骼疾病中受到干扰。通过深入了解骨基质形成和生物矿化的合成代谢过程，我们对骨骼发育、骨折愈合和骨重塑的理解将得到加强。人们对鉴定使骨矿物质（生物磷灰石）成核的生物分子非常感兴趣。该提议假设新合成的骨唾液蛋白（BSP）在与膜界定的囊泡结合时使生物磷灰石成核。该假设将使用天然骨膜和三种成骨细胞培养模型进行测试。我们在大鼠出生后胫骨骨膜以及原代和细胞系成骨细胞培养物中观察到球形（亚）微米大小的含磷灰石颗粒（“生物磷灰石囊泡”）。它们含有 BSP，并且在外观上与类骨质中观察到的矿化结构（“晶体鬼聚集体”）惊人地相似。提出了四个目标来解决“生物磷灰石载体”中 BSP 和磷灰石的结构/功能关系。 (1) 表征从产后骨膜中分离出的生物磷灰石载体的结构。 (2) 在出生后骨膜中原位空间定位纯化生物磷灰石载体的主要成分。 (3) 鉴定并表征来自成骨细胞培养物的任何生物磷灰石载体对应物。 (4)从转染到成骨细胞中的诱导型基因构建体中过度表达BSP。目标 1 和 2 将提供精确的成分数据库，以将生物磷灰石载体的结构与基质囊泡和晶鬼聚集体的结构进行比较。目标 3 将确定相关的培养模型，以评估形成机制并确定必要的分子成分。目标 4 将直接测试 BSP 的过度表达是否增强磷灰石成核以及它是否是生物磷灰石载体完整性的关键结构成分。这项拟议的研究将对成骨细胞形成磷灰石产生新的见解，因为它将分析独特的成核结构并确定 BSP 在这些实体中的功能。最终，我们相信，这些新型生物矿化结构的表征将有助于更好地理解骨骼矿化机制，并可能导致改善骨矿化疾病的新疗法。