CELL MATRIX RESPONSE TO MECHANICAL LOADING

细胞基质对机械载荷的响应

• 批准号: 6100407
• 负责人: KEITH A HRUSKA
• 金额: $ 24.58万
• 依托单位: BARNES-JEWISH HOSPITAL
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-07-01 至 2000-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6100407
• 关键词: antisense nucleic acid; biological signal transduction; biomechanics; blocking antibody; cell adhesion; cell cycle; cytoskeleton; gene targeting; genetically modified animals; guanine nucleotide binding protein; immediate early protein; immunofluorescence technique; integrins; laboratory mouse; mitogen activated protein kinase; osteoblasts; osteogenesis; protein tyrosine kinase; tissue /cell culture; transcription factor; transfection

Stress of adult bone by mechanical loading stimulates new bone formation. There have been many in vitro models and examples of this phenomenon in vivo studied in recent years. The mechanisms by which mechanical loading stimulate bone formation are unknown, but the basis for stating a cogent testable hypothesis has been developed. A basic mechanism of cell-matrix interaction has been discovered, that of cellular integrins serving as matrix proteins. Integrins are heterodimers of alpha and beta components, with each component having large extracellular domains responsible for ligand binding, a transmembrane domain, and a short cytoplasmic domain responsible for interacting with the actin cytoskeleton and organizing signal transduction. The central hypothesis of this project is that mechanical strain activates specific integrins in osteoblast focal adhesions lead to generation of cell signals that culminate in osteoblast precursor proliferation, increased production of bone matrix proteins, and bone formation. Secondary hypothesis are integrin signaling for proliferation may be determined by the recruitment of the adaptor protein. Shc to the integrin signaling complex; that mechanical loading translocates and activates the non-receptor protein tyrosine kinase, c- src; and that the p21ras pathway involving the rho family of GTP binding proteins are activated loading to stimulation of MAP kinase and downstream transcription factors, immediate early gene activation and eventually to cell cycle progression, replication, differentiation and bone formation. The specific aims are to: 1) characterize the effects of mechanical strain on osteoblast cell-matrix interactions; 2) characterize signal transduction in the osteoblast response to mechanical loading. Studies will be performed in cultures of human osteoblasts and marrow stromal cells differentiating along the osteoblastic program. Blocked antibodies, antisense strategies, and dominant negative transfections will be used to interdict specific pathways identified as key during the studies. As the result of the studies in this proposal, we should develop a careful analysis of how an important anabolic factor, mechanical loading, works to build bone. This should serve as a foundation to analyze manipulations of the pathway for therapeutic purposes. Techniques for stimulating new bone formation are badly needed in modern medicine.

通过机械载荷的成年骨骼应力刺激新的骨形成。 有许多体外模型和这种现象的例子 Vivo近年来学习。机械加载的机制 刺激骨形成是未知的，但陈述有力的基础 已经开发了可检验的假设。细胞矩阵的基本机制 已经发现了相互作用，即细胞整合素的相互作用 基质蛋白。整联蛋白是α和β成分的异二聚体， 每个组件都有较大的细胞外域负责 配体结合，跨膜结构域和短细胞质结构域 负责与肌动蛋白细胞骨架并组织 信号转导。该项目的中心假设是 机械应变激活成骨细胞焦点中的特定整合蛋白 粘附导致在成骨细胞中达到顶点的细胞信号的产生 前体增殖，增加骨基质蛋白的产生，以及 骨形成。次要假设是整联蛋白信号传导 增殖可以通过募集衔接蛋白的募集来确定。 SHC到整联蛋白信号传导复合物；那个机械载荷 易位并激活非受体蛋白酪氨酸激酶C- src;并涉及涉及GTP结合的Rho家族的P21RAS途径 蛋白质被激活以刺激MAP激酶和下游 转录因子，立即的早期基因激活，最终 细胞周期进程，复制，分化和骨形成。 具体目的是：1）表征机械应变的影响 在成骨细胞中的相互作用上； 2）表征信号 成骨细胞对机械负荷的反应的转导。研究 将在人类成骨细胞和骨髓stromal的培养物中进行 细胞沿成骨细胞程序区分。阻塞抗体， 反义策略和主要的负转染将用于 在研究期间，固定特定的途径被确定为关键。作为 该提案的研究结果，我们应该仔细 分析重要的合成代谢因素（机械负载）如何作用 建立骨头。这应该是分析操纵的基础 用于治疗目的的途径。刺激新骨的技术 在现代医学中，需要形成。