ROLE OF MATRIX VESICLES IN CALCIFICATION

钙化是一个生物学过程， 包括人类在内的所有脊椎动物。然而， 血管壁和瓣膜中的矿物质沉积 对动脉硬化的发病机制有重要意义。 尽管其关键 重要的是，钙化的机制还没有很好地理解。 的 拟议研究的长期目标是阐明机制 软骨内钙化 这个钙化系统不仅对 骨发育，但似乎也非常类似于异位 矿物沉积 拟议的研究将探讨矩阵的作用 囊泡（MV）结构现在被广泛接受为两个正常的启动子 软骨钙化和早期骨形成，在机制 矿物沉积 注意力将集中在1）钙的代谢 和Pi，以及MV中非常早期的矿物形式的特征， 矿物质形成的诱导，2）关键MV蛋白的表征 3）探讨MV与 胶原在矿物质沉积中的作用; 4）特异性抑制剂的应用 阐明MV矿物沉积的事件顺序。 特别 注意力将被引导到：a）组成MV的表征 蛋白质[新发现的脂质依赖性Ca 2+结合蛋白， 水溶性外周蛋白和胶原结合蛋白]， 它们与MV诱导矿物形成的关系，B） MV早期阶段形成的矿物前驱体的表征 矿化，和c）阐明电解质的作用， 成矿环境 骺生长板软骨 快速生长的鸡将被用来提供丰富的 用于分离细胞和MV的活性钙化材料。 实验 方法将包括：组织分级、细胞培养、MV测定 45 Ca-和32 Pi-代谢，蛋白质纯化（提取， 色谱法、电泳）和使用氨基酸 分析，肽图谱和测序，免疫学（多克隆和 单克隆抗体，蛋白质印迹）和分子生物学（mRNA 分离、北方印迹、cDNA文库、cDNA克隆和测序）。 光谱（FTIR、NMR、UV）、电子显微镜和X射线衍射 将用于表征MV矿物相。

Calcification is a biological process absolutely essential to the survival of all vertebrate organisms, including man. However, the unwanted deposition of mineral in vascular walls and valves contributes significantly to pathogenesis in arteriosclerosis. Despite its critical importance, the mechanism of calcification is not well understood. The long-term objective of the proposed research is to elucidate the mechanism of endochondral calcification. This calcifying system is not only critical to bone development, but also appears to be closely analogous to ectopic mineral deposition. The proposed research will explore the role of matrix vesicles (MV) structures now widely accepted as initiators of both normal calcification in cartilage and early bone formation, in the mechanism of mineral deposition. Attention will be focused on 1) the metabolism of Ca and Pi, and the characterization of very early mineral forms in MV during the induction of mineral formation, 2) characterization of key MV proteins involved in this process, 3) exploration of the relationship between MV and collagen in mineral deposition, and 4) utilization of specific inhibitors to elucidate the sequence of events in MV mineral deposition. Special attention will be directed towards: a) characterization of constitutive MV proteins [the newly-discovered lipid-dependent Ca2+-binding proteins, the water-soluble peripheral proteins, and the collagen-binding proteins] and their relationship to the induction of mineral formation by MV, b) characterization of mineral precursors formed during early stages of MV mineralization, and c) elucidating the effect of the electrolyte environment on MV mineralization. Epiphyseal growth plate cartilage from rapidly growing chickens will be used to provide an abundant source of actively calcifying material for isolation of cells and MV. Experimental methods will include: Tissue fractionation, cell culture, assays of MV 45Ca- and 32Pi-metabolism, protein purification (extraction, chromatography, electrophoresis) and characterization using amino acid analysis, peptide mapping and sequencing, immunology (polyclonal and monoclonal antibodies, Western blots) and molecular biology (mRNA isolation, Northern blots, cDNA library, cDNA cloning and sequencing). Spectroscopy (FTIR, NMR, UV), electron microscopy and x-ray diffraction will be used to characterize MV mineral phases.