Osteocyte differentiation & MCP-3 chemoattractant in mechanical stress responses

骨细胞分化

• 批准号: 6583193
• 负责人: STEPHEN Eubank HARRIS
• 金额: $ 21.52万
• 依托单位: UNIVERSITY OF TEXAS HLTH SCIENCE CENTER
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-04-01 至 2003-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6583193
• 关键词: cell differentiation; cell line; chemoattractants; chickens; cytology; gene expression; genetic regulation; genetic transcription; genetically modified animals; laboratory mouse; mechanical stress; monocyte chemoattractant protein 1; osteoblasts; osteocytes; protein localization; protein structure function; receptor expression; tissue /cell culture

Osteoblasts are the precursors to osteocytes. A specific genetic program and gene expression profile underlies this differentiation process to a mature osteocyte, but the detailed components of that program are unknown. We have begun to define a subset of gene expression patterns that represent the state of the osteoblast as it progresses towards an osteocyte surrounded by osteoid that is actively mineralizing. Using osteoblast and osteocyte models composed of two cell lines, 2T3, an osteoblast-like cell, and MLO-Y4, an osteocyte-like cell, we have defined a subset of genes that are low in osteoblasts and become highly expressed in the osteocytes model. Additionally, a subset of genes in the osteocyte that respond to fluid flow have been identified Additionally, a subset of genes in the osteocyte that respond to fluid flow have been identified. One genes that encodes for Monocyte Chemoattractant Protein, MCP-3, is 13 TO 19 fold higher in osteocytes compared to osteoblast becomes an osteocyte and identify genes important for osteocyte function. The short- term goal is to determine the role of MCP-3 in osteocyte function. Our hypothesis is that MCP-3 is a marker for differentiation of osteoblasts into osteocytes and a critical molecule in recruitment of osteoclast precursors to bone. In this proposal we will address 1) the role of MCP-3 in osteocyte function and 2) the regulation of MCP-3 gene expression under mechanical strain both in vitro and in vivo. To accomplish these goals, the MPO-Y4 cell line, primary osteocytes, primary osteoblasts and the 2T3 cell line that forms mineralized nodules containing osteocyte-like cells in culture will be used. Increasing magnitude and frequency of fluid flow will be tested for effect on MCP-3 production, gene expression patterns and function in these models. Two rodent in vivo models of mechanical strain, the tooth movement model and ulnae-fatigue loading model will be used to access and validate gene expression changes found in the in vitro models. We will also use transgenic mice with a null allele of the MCP receptor, CCR2 mice will have defects in osteoclast precursor recruitment. Results from these studies will dramatically expand our database on genes important for osteocyte function and should also lead to insights into the mechanism of osteoclast recruitment to sties of bone microfracture.

成骨细胞是骨细胞的前体。一个特定的遗传程序和基因表达谱是成熟骨细胞分化过程的基础，但该程序的详细组成部分尚不清楚。我们已经开始定义一个基因表达模式的子集，它代表了成骨细胞的状态，因为它向被积极矿化的类骨细胞包围的骨细胞发展。利用由两种细胞系组成的成骨细胞和骨细胞模型，2T3（一种成骨细胞样细胞）和MLO-Y4（一种成骨细胞样细胞），我们定义了成骨细胞中低表达并在骨细胞模型中高度表达的基因亚群。此外，已经确定了骨细胞中对流体流动有反应的基因子集。此外，已经确定了骨细胞中对流体流动有反应的基因子集。一个编码单核细胞化学吸引蛋白MCP-3的基因在成骨细胞中比成骨细胞高13到19倍，成为骨细胞并识别对骨细胞功能重要的基因。短期目标是确定MCP-3在骨细胞功能中的作用。我们的假设是MCP-3是成骨细胞向骨细胞分化的标志，也是破骨细胞前体向骨募集的关键分子。在本提案中，我们将解决1)MCP-3在骨细胞功能中的作用，2)体外和体内机械应变下MCP-3基因表达的调控。为了实现这些目标，将使用MPO-Y4细胞系、原代骨细胞、原代成骨细胞和在培养中形成含有骨细胞样细胞的矿化结节的2T3细胞系。在这些模型中，将测试增加流体流动的幅度和频率对MCP-3产生、基因表达模式和功能的影响。两种啮齿动物体内力学应变模型，即牙齿运动模型和尺骨疲劳载荷模型，将用于获取和验证在体外模型中发现的基因表达变化。我们还将使用带有MCP受体空等位基因的转基因小鼠，CCR2小鼠将在破骨细胞前体募集方面存在缺陷。这些研究的结果将极大地扩展我们对骨细胞功能重要基因的数据库，也将导致对破骨细胞募集到骨微骨折的机制的深入了解。