Multiaxial Single-Cell Biomechanics for Mechanotransduction

描述(申请人提供)：许多组织的发展、重塑和发病部分依赖于机械信号。将关节软骨所经历的力学环境转化为生物分子反应的力学转导的基础将首先通过单个软骨细胞的操作来探索。健康的软骨细胞承受流体静力、压缩、拉伸和剪切力，以维持新软骨组织的表型和产生。由于单一循环或疲劳负荷引起的异常机械力，已被证明改变软骨细胞的行为，导致病理性基质合成，增加分解代谢活性(降解)，最终导致骨关节炎(细胞凋亡)。研究起源于特定软骨区的单个细胞的生物力学对于破译不同组织水平的力到细胞内分子机制的传递至关重要。对个体细胞生物力学的更完整的了解将优先考虑对刺激再生过程最关键的生物力学因素。由于对于机械信号在调节细胞功能方面的最佳效果还没有达成共识，因此还有很多有待研究的地方。我们最近开发了一种集成/微粒子图像测速/光钳(5PIVOT)系统来实现这一目标。该装置被设计为一种独特的工具，旨在研究细胞力学并促进机械生物学的表征。基于激光的技术已经被定制集成，以物理地保持细胞或分子结构，同时监测流体和光学力诱导的结构变形。该项目的目的是建立一个5PIVOT系统应用于单个软骨细胞生物力学的可行性，作为力学转导的先驱。这项工作将支持学术研究增强奖(AREA)计划，其具体目标如下：1)优化两个光学系统的集成，以测量单个活细胞的多轴生物力学特性；2)在测量由此产生的应变响应的同时，对单个软骨细胞施加一系列单轴和多轴应力。这一领域的成功成果随后可用于探索最有效地诱导机械转导的环境。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，有助于了解承重组织的病理细胞状态和治疗方法，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