力敏感离子通道调控软骨细胞感受基质物理特性的机制研究

The matrix physical properties of chondrocyte, including stiffness and 3D shape, have strong influences on regulating chondrocyte behavior and function. Elucidating the mechanism of chondrocyte sensing stiffness and 3D shape has significant scientific meanings. In this project, the physiological related matrix physical properties of chondrocytes will be recapitalized to study the mechanism of mechanosensitive ion channel BKCa and TRPV4 regulating chondrocytes sensing matrix stiffness and 3D shape. The main contents including: the effect of matrix stiffness and 3D shape on the cell morphology, mechanical properties, F-actin distribution, focal adhesion dynamics and regulatory volume decrease; The interaction between BKCa, TRPV4 channel and focal adhesion, and the mechanism of mechanical-electrical transduction. The mechanism of BKCaand TRPV4 channel regulating the calcium signaling, mechanical behavior and regulator volume decrease of chondrocytes sensing matrix stiffness and 3D shape; the biophysical properties and functional coupling of BKCa and TRPV4 channel during chondrocytes sensing matrix stiffness and 3D shape. This project will contribute to understand the development and degeneration of articular cartilage, and provide important information for achieving desired cell function through reasonable optimization of the physical property of matrix.

基质物理特性（刚度和三维形状）对软骨细胞行为和功能有着重要调控作用。揭示调控软骨细胞感受基质刚度和三维形状的机制具有重要科学意义。本项目拟近似反演软骨细胞生理相关的基质物理特性，研究力敏感离子通道BKCa和TRPV4通道调控软骨细胞感受基质刚度和三维形状的机制。主要研究内容包括：基质刚度和三维形状对软骨细胞形态、力学特性、骨架蛋白分布、粘着斑生长和调节性容积回缩的影响；BKCa和TRPV4通道与焦点粘着斑的相互作用及其力电转导机制；BKCa和TRPV4通道对软骨细胞感受基质刚度和三维形状过程中钙信号转导、力学行为和调节性容积回缩的调控机制；BKCa和TRPV4通道在软骨细胞感受基质刚度和三维形状过程的生物物理特性和功能耦联。本项目研究有助于理解关节软骨生长和OA退变过程软骨细胞的力学生物学行为，也可为软骨组织工程合理优化基质物理特性以获得预期细胞功能提供参考。

在关节软骨中，软骨细胞功能和行为受到细胞周基质物理特性（刚度和三维形状）的重要调控。本项目反演软骨细胞生理相关的基质物理特性，研究了力敏感离子通道TRPV4和PIEZOs通道调控软骨细胞感受基质刚度和三维形状的机制。主要内容包括：研究了TRPV4和PIEZOs在周期性拉伸应变激活软骨细胞钙信号中的作用，揭示了TRPV4介导调控软骨细胞生理应变刺激时的钙信号，而PIEZOs 则调控动态损伤应变时的钙信号；研究了基底硬度对TRPV4/PIEZOs和细胞钙信号的影响，指出了软骨细胞可能利用TRPV4和PIEZOs对基底硬度具有不同生物物理特性的特点感受基质力学环境；研究了基底形状对软骨细胞钙信号和力学特性的调控，软骨细胞在高形状因子的培养基底中表现出较高的黏弹性特性和钙强度。研究了基底刚度调控软骨细胞调控性体积回缩（regulatory volume decrease, RVD）过程中细胞动态力学和生物学行为。软骨细胞RVD膨胀和回缩过程各项参数均具有基底硬度依赖性。RVD膨胀和回缩过程的细胞内钙震荡的幅值和频率与基底硬度具有明显相关性。为探索三维基质力学微环境中细胞—基质相互作用的力转导机制提供了三维研究平台，同时也为软骨组织工程支架生物材料设计和优化提供了思路。