Mineralization Studies Related to Oral Biology

与口腔生物学相关的矿化研究

• 批准号: 6727419
• 负责人: HARRISON CLARKE ANDERSON
• 金额: $ 33.75万
• 依托单位: UNIVERSITY OF KANSAS MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 1978
• 资助国家: 美国
• 起止时间: 1978-03-01 至 2005-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6727419
• 关键词: alkaline phosphatase; apoptosis; bone morphogenetic proteins; calcification; calcium transporting ATPase; calpain; cartilage; cell differentiation; cell growth regulation; chondrocytes; dentin; enzyme activity; extracellular matrix proteins; gene targeting; genetically modified animals; hydroxyapatites; laboratory mouse; membrane proteins; osteocalcin; osteonectin; osteopontin; protein structure function; pyrophosphates; tissue /cell culture; western blottings

DESCRIPTION (provided by applicant): The proposed study is focused on matrix vesicles (MVs) which play an initiating role in the mineralization of teeth and bones. MVs are submicroscopic, extracellular, membrane-invested particles that serve as the initial site of calcification in dentin, growth plate cartilage and developing bone. Our lab was involved in the first identification, isolation and characterization of MVs. We and others have provided evidence that MV phosphatases, including alkaline phosphatase (ALP), and ATPase are involved in MV mineralization. Furthermore, these phosphatases are integrated into the MV membrane beneath which mineral first appears, suggesting a critical role for components of the MV membrane in initiating calcification. Our study is directed toward an increased understanding of the mechanism by which MVs initiate biomineralization. We will examine the interaction of constitutive MV phosphatases, e.g. alkaline phosphatase (ALP), ATPase, nucleotide triphosphate pyrophosphohydrolase (NTPPase) and inorganic pyrophosphatase (PPiase), in regulating the mineralization of isolated MVs from rat growth plate, and in promoting or inhibiting in vivo MV mineralization using normal versus transgenic mice with ALP and/or NTPPase gene inactivation. Since programmed cell death has been suggested as a necessary precondition for MV biogenesis in growth plate, we will examine the role of chondrocyte apoptosis in the generation of mineralization-competent MVs by cultured rat growth plate chondrocytes. Following up on our preliminary observation that isolated rat MVs contain significant amounts of bone morphogenetic proteins (BMPs) we will test the hypothesis that extracellular BMPs, residing in the MVs of growth plate cartilage are carriers of morphogenetic signals that regulate new bone formation following their release by cartilage matrix resorption in metaphyses and secondary ossification centers. Specific Aims: 1) a further characterization of the role MV phosphatases in regulating MV initiated biomineralization. 2) Studies of the effect of genetically induced hypophosphatasia and/or hypopyrophosphatasia on MV-initiated biomineralization in mutant mice. 3) A study of the mechanism of MV biogenesis by chondrocyte plasma membrane budding and whether MV biogenesis is regulated by programmed cell death (apoptosis). 4) Studies to confirm the presence of BMPs in isolated rat growth plate MVs, and to determine whether matrix vesicle BMPs can promote chondro- osseous differentiation. This is a fundamental study of the mechanism by which dental and skeletal forms of mineralization are initiated. New knowledge of matrix vesicle calcification can be applied to a broad range of topics including specific diseases in which abnormal calcification occurs.

描述（由申请人提供）：拟议的研究集中在基质囊泡（MV）上，这些基质囊泡在牙齿和骨骼的矿化中起发挥作用。 MV是亚显微镜，细胞外，膜侵入的颗粒，可作为牙本质，生长板软骨和发育骨骼的钙化的初始位点。我们的实验室参与了MV的首次识别，隔离和表征。我们和其他人提供了证据，表明包括碱性磷酸酶（ALP）和ATPase在内的MV磷酸酶参与MV矿化。此外，这些磷酸酶首次出现矿物质下方的MV膜整合在一起，这表明MV膜在启动钙化中的成分至关重要。我们的研究是针对对MV启动生物矿化机制的增强理解的。我们将研究组成型MV磷酸酶的相互作用，例如alkaline phosphatase (ALP), ATPase, nucleotide triphosphate pyrophosphohydrolase (NTPPase) and inorganic pyrophosphatase (PPiase), in regulating the mineralization of isolated MVs from rat growth plate, and in promoting or inhibiting in vivo MV mineralization using normal versus transgenic mice with ALP and/or NTPPase gene失活。由于已经提出了编程细胞死亡作为生长板中MV生物发生的必要前提，因此我们将研究软骨细胞凋亡在培养的大鼠生长板软骨细胞中产生矿化能力MVS的作用。遵循我们的初步观察，即孤立的大鼠MV含有大量的骨形态发生蛋白（BMP），我们将测试以下假设：驻留在生长板软骨MV中的细胞外BMP是形态发生信号的载体，这些载体是形态遗传信号，这些信号通过软骨矩阵的释放而释放出新的骨骼，并以含量为单位释放，并在其下进行了含量。 具体目的：1）进一步表征MV磷酸酶在调节MV启动生物矿化中的作用。 2）研究遗传诱导的下磷酸症和/或直闭磷酸磷酸对突变小鼠MV启动的生物矿化的影响。 3）对软骨细胞质膜萌芽的MV生物发生机制的研究，以及MV生物发生是否通过程序性细胞死亡（凋亡）调节。 4）研究确认在分离的大鼠生长板MV中存在BMP，并确定基质囊泡BMP是否可以促进软骨骨分化。这是对启动牙齿和骨骼形式矿化的机制的基本研究。基质囊泡钙化的新知识可以应用于广泛的主题，包括发生异常钙化的特定疾病。