Do Tien-Dung, Katsuyoshi Jimuro, Cai Haonai, Ohashi Toshiro
Division of Human Mechanical Systems and Design, Graduate School of Engineering, Hokkaido University, Sapporo, Japan.
Division of Mechanical and Aerospace Engineering, Faculty of Engineering, Hokkaido University, Sapporo, Japan.
Front Bioeng Biotechnol. 2021 Nov 11;9:753805. doi: 10.3389/fbioe.2021.753805. eCollection 2021.
Mechanotransduction is a well-known mechanism by which cells sense their surrounding mechanical environment, convert mechanical stimuli into biochemical signals, and eventually change their morphology and functions. Primary cilia are believed to be mechanosensors existing on the surface of the cell membrane and support cells to sense surrounding mechanical signals. Knowing the mechanical properties of primary cilia is essential to understand their responses, such as sensitivity to mechanical stimuli. Previous studies have so far conducted flow experiments or optical trap techniques to measure the flexural rigidity (: Young's modulus, : second moment of inertia) of primary cilia; however, the flexural rigidity is not a material property of materials and depends on mathematical models used in the determination, leading to a discrepancy between studies. For better characterization of primary cilia mechanics, Young's modulus should be directly and precisely measured. In this study, the tensile Young's modulus of isolated primary cilia is, for the first time, measured by using an in-house micro-tensile tester. The different strain rates of 0.01-0.3 s were applied to isolated primary cilia, which showed a strain rate-dependent Young's modulus in the range of 69.5-240.0 kPa on average. Atomic force microscopy was also performed to measure the local Young's modulus of primary cilia, showing the Young's modulus within the order of tens to hundreds of kPa. This study could directly provide the global and local Young's moduli, which will benefit better understanding of primary cilia mechanics.
机械转导是一种众所周知的机制，通过该机制细胞感知其周围的机械环境，将机械刺激转化为生化信号，并最终改变其形态和功能。初级纤毛被认为是存在于细胞膜表面的机械传感器，支持细胞感知周围的机械信号。了解初级纤毛的机械特性对于理解它们的反应至关重要，例如对机械刺激的敏感性。先前的研究已经进行了流动实验或光镊技术来测量初级纤毛的弯曲刚度（：杨氏模量，：惯性矩）；然而，弯曲刚度不是材料的材料属性，并且取决于测定中使用的数学模型，导致研究之间存在差异。为了更好地表征初级纤毛力学，应该直接且精确地测量杨氏模量。在本研究中，首次使用自制的微拉伸测试仪测量了分离的初级纤毛的拉伸杨氏模量。对分离的初级纤毛施加了0.01-0.3 s的不同应变速率，其平均杨氏模量在69.5-240.0 kPa范围内表现出应变率依赖性。还进行了原子力显微镜测量初级纤毛的局部杨氏模量，显示杨氏模量在几十到几百kPa的量级内。这项研究可以直接提供全局和局部杨氏模量，这将有助于更好地理解初级纤毛力学。
