Forces generated by chondrocytes on collagen fibers

描述（由申请人提供）： 关节软骨细胞具有有限的组织修复能力，导致关节软骨的退行性变化，包括骨关节炎。已知控制这些细胞代谢行为的一个因素是机械力。然而，软骨细胞感知机械力并对其做出反应的机制尚不清楚。最近的研究表明，粘着斑复合物可能通过细胞骨架连接增强过程充当机械信号转换器。该项目的主要假设是，软骨细胞与其周围细胞外基质之间的粘着斑作为力传感器，将机械信号转化为可能改变细胞功能的生化信号。为了验证这一假设，一个新的实验系统的基础上的微机械力传感装置将被用来研究单个分离的细胞和单个胶原纤维之间的相互作用。该系统将用于执行以下特定目标：（1）量化单个分离软骨细胞对单个胶原纤维施加的力;（2）使用绿色荧光蛋白标记标记物检查单个胶原纤维下粘着斑部位的组装;（3）检查粘着斑对通过单个胶原纤维施加的静态和动态机械力的反应。确定局灶性粘连在机械信号转导中的作用将导致对机械力在体内关节软骨退化和体外组织工程修复策略发展中的作用的更好理解。

DESCRIPTION (provided by applicant): Articular chondrocytes have a limited capacity for tissue repair, contributing to degenerative changes in articular cartilage, including osteoarthritis. One factor that is known to control the metabolic behavior of these cells is mechanical forces. However, the mechanisms by which chondrocytes sense and respond to mechanical forces are not well understood, Recent studies have suggested that the focal adhesion complex may serve as a mechanical signal transducer, through a process of cytoskeletal linkage reinforcement. The governing hypothesis of this project is that focal adhesion sites between the chondrocyte and its surrounding extracellular matrix serve as force transducers, converting mechanical signals into biochemical signals that may alter cellular function. To test this hypothesis, a novel experimental system based on a micromachined force sensing device will be used to study interactions between single isolated cells and single collagen fibers. This system will be used to execute the following specific aims: (1) Quantify the forces exerted by single isolated chondrocytes on individual collagen fibers; (2) Examine the assembly of focal adhesion sites under single collagen fibers using green fluorescence protein-labeled markers; (3) Examine the response of focal adhesions to static and dynamic mechanical forces applied through single collagen fibers. Determining the role of focal adhesions in mechanical signal transduction will lead to a greater understanding of the role of mechanical forces in both degeneration of articular cartilage in vivo and development of tissue engineered repair strategies in vitro.