ECM Molecules in Chondrocyte Mechanotransduction

软骨细胞机械转导中的 ECM 分子

• 批准号: 6909875
• 负责人: RONALD DAVID GRAFF
• 金额: $ 7.3万
• 依托单位: UNIV OF NORTH CAROLINA CHAPEL HILL
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-07-01 至 2007-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6909875
• 关键词: adenosine triphosphate; animal tissue; antibody; atomic force microscopy; binding proteins; biological signal transduction; biomechanics; calcium flux; cell adhesion molecules; cell cell interaction; cell surface receptors; chondrocytes; confocal scanning microscopy; enzyme activity; extracellular matrix; fibronectins; fluidity; fluorescence microscopy; immunomagnetic separation; intracellular transport; mitogen activated protein kinase; phosphorylation; protein glutamine gamma glutamyltransferase; tissue /cell culture; western blottings

DESCRIPTION (provided by applicant): Appropriate mechanical stimulation is crucial for maintenance of articular cartilage. Aberrant mechanical loading can lead to the initiation or progression of osteoarthritis. The mechanisms by which chondrocytes sense or respond to mechanical loading in healthy and diseased cartilage are not fully understood. Articular chondrocytes are encapsulated in a complex pericellular matrix composed mainly of fibrillar collagens, hyaluronan, proteoglycans, fibronectin and laminin. This PCM links the chondrocyte to its extracellular environment through cell surface receptors (integrins and CD44), and protects the chondrocyte from osmotic challenge and deformation during mechanical load. Preliminary data indicate that accumulation of extracellular matrix by chondrocytes in culture is concomitant with decreasing rates of ATP release and an increase in intracellular calcium mobilization in response to fluid shear (or stimulation). It is hypothesized therefore that deposition of extracellular matrix alters the mechanical responsiveness and that individual components of the pericellular matrix differentially regulate mechanotransduction in chondrocytes. This hypothesis will be tested in cultured primary chondrocytes using two novel systems: a microplate mechanotransduction assay developed by the principal investigator, and a fluorescence-coupled three-dimensional atomic force microscope capable of delivering precisely measured forces to magnetic beads. Comparison of cell signaling events initiated by chondrocytes on different substrata will help to identify key elements within the pericellular environment that modulate or control the metabolism of chondrocytes during mechanical loading in normal and diseased cartilage. Such comparison will also identify likely chondrocyte mechanoreceptors (such as integrins, or CD44), based on their relative affinities for different ECM molecules. Learning the role of specific ECM molecules in chondrocyte mechanotransduction will increase our understanding of the pathogenesis of osteoarthritis and may aid in designing novel therapies for slowing progression.

描述（由申请人提供）：适当的机械刺激对于维持关节软骨至关重要。异常的机械负荷可导致骨关节炎的发生或进展。软骨细胞感知或响应健康和患病软骨中的机械负荷的机制尚不完全清楚。关节软骨细胞被包裹在复杂的细胞周基质中，该基质主要由纤维状胶原、透明质酸、蛋白聚糖、纤连蛋白和层粘连蛋白组成。这种 PCM 通过细胞表面受体（整合素和 CD44）将软骨细胞与其细胞外环境连接起来，并保护软骨细胞在机械负载期间免受渗透压挑战和变形。初步数据表明，培养物中软骨细胞积累的细胞外基质伴随着 ATP 释放速率的降低和响应于流体剪切（或刺激）的细胞内钙动员的增加。因此，推测细胞外基质的沉积改变了机械反应性，并且细胞周基质的各个成分差异性地调节软骨细胞中的机械转导。该假设将使用两种新颖的系统在培养的原代软骨细胞中进行测试：由主要研究人员开发的微板机械转导测定，以及能够向磁珠传递精确测量的力的荧光耦合三维原子力显微镜。比较不同基质上软骨细胞引发的细胞信号事件将有助于识别细胞周环境中的关键元素，这些元素在正常和患病软骨的机械负荷过程中调节或控制软骨细胞的代谢。这种比较还将根据软骨细胞机械感受器（例如整合素或 CD44）与不同 ECM 分子的相对亲和力来识别可能的软骨细胞机械感受器。了解特定 ECM 分子在软骨细胞机械转导中的作用将增加我们对骨关节炎发病机制的理解，并可能有助于设计减缓进展的新疗法。