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。已知的控制这些细胞代谢行为的一个因素是机械力。然而，软骨细胞感知和响应机械力的机制还不是很清楚，最近的研究表明，粘着斑复合体可能通过细胞骨架连接加强的过程作为机械信号转导。该项目的主要假设是，软骨细胞与其周围的细胞外基质之间的局部粘连部位作为力传送器，将机械信号转换为生化信号，从而可能改变细胞功能。为了验证这一假设，将使用一种基于微机械作用力传感装置的新型实验系统来研究单个分离细胞和单个胶原纤维之间的相互作用。该系统将用于实现以下特定目标：(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测单个胶原纤维下局部粘连部位的组装；(3)检测局部粘连对通过单个胶原纤维施加的静态和动态机械力的反应。确定局部粘连在力学信号转导中的作用将有助于更好地理解机械力在体内关节软骨退变和体外组织工程化修复策略发展中的作用。

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.