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。异常的机械负荷会导致骨关节炎的启动或进展。没有完全了解软骨细胞感知或对机械负荷反应的机制。关节软骨细胞封装在复杂的细胞周围基质中，主要由原纤维胶原，透明质酸，蛋白聚糖，纤维蛋白和层粘连蛋白组成。该PCM通过细胞表面受体（整联蛋白和CD44）将软骨细胞与其细胞外环境联系起来，并保护软骨细胞在机械载荷期间免受渗透挑战和变形。初步数据表明，软骨细胞在培养物中的细胞外基质的积累与ATP释放速率的降低和对流体剪切（或刺激）的响应时细胞内钙动员的增加相关。因此，假设细胞外基质的沉积会改变周围基质的机械反应性，并改变了细胞周围基质的各个成分，对软骨细胞中的机械转导差异调节。该假设将使用两个新型系统在培养的原代软骨细胞中进行测试：主要研究者开发的微板机械传输测定法，以及一个荧光耦合的三维原子力显微镜，能够将精确测量的力传递到磁珠上。软骨细胞在不同基质上引发的细胞信号传导事件的比较将有助于确定细胞周环境中的关键元素，这些元素在正常和患病软骨中机械负荷过程中调节或控制软骨细胞的代谢。这种比较还将根据其对不同ECM分子的相对亲和力，确定可能的软骨细胞机械感受器（例如整联蛋白或CD44）。学习特定的ECM分子在软骨细胞机械转导的作用将增加我们对骨关节炎发病机理的理解，并可能有助于设计新的疗法来减缓进展。