Multiaxial Single-Cell Biomechanics for Mechanotransduction

描述（由申请人提供）：许多组织的发育、重塑和发病机制部分依赖于机械信号。将关节软骨所经历的机械环境转化为生物分子反应的机械转导的基础将首先通过单个软骨细胞的操纵来探索。健康的软骨细胞经历流体静力、压缩、拉伸和剪切力，维持新软骨组织的表型和产生。单循环或疲劳负荷引起的异常机械力已被证明会改变软骨细胞的行为，导致病理性基质合成，分解代谢活性增加（降解），最终导致骨关节炎（细胞凋亡）。研究源自特定软骨区的单细胞的生物力学对于破译细胞内分子机制的异质性组织水平力的传递至关重要。更完整的个体细胞生物力学知识将优先考虑刺激再生过程最关键的生物力学因素。由于没有共识的机械信号，是最有效的调节细胞功能，许多有待研究。为了实现这一目标，我们最近开发了一种集成/微粒子图像测速/光学镊子（5PIVOT）系统。该装置被设计为一种独特的工具，旨在研究细胞力学和促进力学生物学的表征。基于激光的技术已被定制集成到物理上保持细胞或分子结构，同时监测流体和光学力引起的结构变形。该项目的目的是建立应用5PIVOT系统进行单个软骨细胞生物力学作为机械转导的先驱的可行性。这项工作将支持学术研究增强奖（AREA）计划，该计划有以下具体目标：1)优化两个光学系统的集成，这些系统以前没有一起使用，用于测量单个活细胞的多轴生物力学特性；2)对单个软骨细胞施加一系列单轴和多轴应力，同时测量由此产生的应变响应。该区域的成功结果可用于探索诱导机械转导最有效的环境。这些研究的完成将对软骨细胞的机械反应提供重要的见解，有助于理解细胞的病理状态和承重组织的治疗方法，并指导控制细胞功能的工程生物材料的设计

DESCRIPTION (provided by applicant): The development, remodeling, and pathogenesis of many tissues depend in part on mechanical signals. The foundation of mechanotransduction which transforms the mechanical environment experienced by articular cartilage into a biomolecular response will initially be explored through single chondrocyte manipulation. Healthy chondrocytes experience hydrostatic, compressive, tensile, and shear forces that maintain the phenotype and production of neocartilaginous tissue. Abnormal mechanical forces due to single cycle or fatigue loading, have been shown to alter chondrocyte behavior, resulting in pathological matrix synthesis, increased catabolic activity (degradation), and ultimately osteoarthritis (apoptosis). Studies of the biomechanics of single cells originating from the specific cartilage zones are critical for deciphering the transmission of heterogeneous tissue-level forces to the molecular machinery within the cell. A more complete knowledge of individual cellular biomechanics will prioritize the biomechanical factors most critical to stimulating regenerative processes. As there is no consensus as to the mechanical signals that are optimally effective in modulating cell function, much is left to be studied. We recently developed an integrated /micro- particle image velocimetry/optical tweezers (5PIVOT) system toward this goal. This device was designed as a unique tool intended to study cellular mechanics and facilitate the characterization of mechanobiology. The laser-based technologies have been custom-integrated to physically hold cellular or molecular structures concomitant with monitoring fluid and optical force-induced deformations of the structure. The objective of this project is to establish the feasibility of applying an 5PIVOT system for single chondrocyte biomechanics as a precursor to mechanotransduction. This effort will support the Academic Research Enhancement Award (AREA) Program as directed by the following specific aims: 1) to optimize the integration of two optical systems, not previously used in concert, for measuring multiaxial biomechanical properties of single living cells; 2) to apply a sequence of single and multiple axis stresses to individual chondrocytes while measuring the resulting strain response. Successful outcomes from this AREA can then be used to explore the environment most effective in inducing mechanotransduction. Completion of these studies should provide significant insight into the mechanical response of chondrocytes, contribute to the understanding of pathologic cell states and therapeutic approaches for load-bearing tissues, and guide the design of engineered biomaterials which control cellular function