Cell-ECM Interactions: A 3D Micro-Mechanical Perspective

描述(由申请人提供)： 这项研究的长期目标是促进开发更好的方法来克服组织丢失和器官衰竭的破坏性问题。这项建议的目的是确定3D细胞外基质(ECM)的特定微结构和机械特性如何定义机械信号的分布和传递到细胞，进而调节细胞的反应并最终对整体组织结构/功能做出贡献。这项研究的中心假设是，在3D ECM中，细胞对微结构组成和微机械载荷的反应部分是由细胞-基质粘连的分布和组成所介导的。这项研究的基本原理是，定义细胞外基质环境的关键3D结构和机械特征，特别是在微观层面，以及确定它们影响细胞行为的机制，将使设计具有特定材料属性的生物材料成为可能，这些材料可预测地诱导细胞反应，从而加速或改善组织修复。本研究的目的有三个方面：1)确定三维ECM中成纤维细胞的形态、表型、细胞-基质黏附和ECM重塑特性，其中微结构可量化且可控地改变，且不施加外部机械载荷；2)确定成纤维细胞在3D ECM中的形态、表型、细胞-基质黏附和ECM重塑特性，其中的微观力学特性(例如，三维微观水平的应力场和应变场)是通过施加外部机械载荷来量化和可控改变的；3)确定成纤维细胞感知周围3D ECM的微结构组成和微观机械状态的机制。ECM生物化学、细胞生物学、生物力学和生物成像领域的专业知识将结合在一起，产生以下结果。首先，将定量定义细胞的ECM微环境的特定结构-机械属性。反过来，在存在和不存在外部施加的机械载荷的情况下，细胞响应对3D ECM的特定微观结构和机械性能的依赖将被建立。第三，将确定其他主要细胞信号对细胞感知和响应这些生物物理线索的能力的影响。第四，将确定与CELI-ECM黏附相关的关键事件，这些事件使细胞能够感知和响应3D ECM微环境的物理属性。总之，这些结果将提供关于细胞-细胞外基质相互作用的物理方面的新信息，并确定细胞-基质粘连在细胞对细胞外基质提供的三维结构和机械信号做出反应的能力中所起的作用。这项研究对组织工程和医学具有重要意义，因为其结果有望确定急需的基本原则和设计标准，为定向修复受损组织奠定基础。

DESCRIPTION (provided by applicant): The long-range goal of the research is to foster development of better approaches to overcome the devastating problems of tissue loss and organ failure. The objective of this proposal is to determine how specific micro-structural and mechanical properties of a 3D extracellular matrix (ECM) define the distribution and transfer of mechanical signals to cells that in turn regulate their response and ultimately contribute to the overall tissue structure/function. The central hypothesis for the research is that the cellular response to micro-structural composition and micro-mechanical loading within a 3D ECM is mediated, in part, by the distribution and composition of cell-matrix adhesions. The rationale for the research is that definition of critical 3D structural and mechanical features of a cell's ECM environment, especially at the micro level, as well as identification of the mechanisms by which they influence cell behavior will make it possible to engineer biomaterials with specific material properties that predictably induce a cellular response that accelerates or improves tissue restoration. The objective of the proposed research will be achieved by pursuing three specific aims: 1) determine the morphological, phenotypic, cell-matrix adhesion, and ECM remodeling properties of fibroblasts within 3D ECMs in which the micro-structure is quantified and controllably varied and no external mechanical loads are applied; 2) determine the morphological, phenotypic, cell-matrix adhesion, and ECM remodeling properties of fibroblasts within 3D ECMs in which the micro-mechanical properties (e.g., 3D micro level stress and strain fields) are quantified and controllably varied by application of external mechanical loads; and 3) identify mechanisms by which fibroblasts perceive the micro-structural composition and micro-mechanical state of the surrounding 3D ECM. Expertise in the areas of ECM biochemistry, cell biology, biomechanics, and bioimaging will be combined to yield the following outcomes. First, specific structural-mechanical attributes of a cell's ECM micro-environment will be quantitatively defined. In turn, the dependence of the cellular response on specific micro-structural and mechanical properties of a 3D ECM will be established in the presence and absence of externally applied mechanical loads. Third, the effect of other major cellular signals on the ability of cells to sense and response to these biophysical cues will be determined. Fourth, key events associated with celI-ECM adhesion that provide cells with the ability to sense and respond to physical properties of a 3D ECM microenvironment will be identified. Collectively, these outcomes will provide new information regarding the physical aspects of celI-ECM interaction and establish the role of cell-matrix adhesions in the ability of cells to respond to 3D structural and mechanical cues provided by the ECM. This research is significant to tissue engineering and medicine because the results are expected to define much needed fundamental principles and design criteria that will lay the foundation for directed repair of damaged tissues.