In Vivo Mechanotransduction During Limb Growth

该奖项支持一项研究项目，该项目旨在研究细胞在四肢形成时的行为。身体中的细胞感知机械环境并对其做出反应。骨骼系统对机械负荷特别敏感；随着机械需求的增加，肌肉、骨骼和肌腱变得更强壮。该项目将探索细胞如何感知和响应机械环境，在肢体再生期间，在一只Axolotl火蜥蜴。在肢体再生过程中，截肢部位会形成大量干细胞。这些细胞生长并变成软骨。软骨生长并骨化，形成有功能的肢体。机械力在整个过程中起着至关重要的作用。我们将探索细胞感知机械环境的机制，以及它们如何将机械刺激转化为生物反应。了解这一过程的工作原理具有广泛的应用，如开发适应力学环境的智能材料或开发适当的物理疗法来纠正力学并确保正常生长。这项工作将有助于阐明机械在肢体生长中的作用：干细胞和软骨细胞中机械敏感的钙信号，涉及的机械触发的离子通道，机械敏感的YES相关蛋白在细胞内的位置，以及机械信号向分子反应的机械转导。由于这项研究使用Axolotl作为肢体再生的模型系统，我们将首次能够在体内评估这些过程，并确定力学在肢体形成过程中的作用。我们还将开发使用荧光原位杂交和荧光标记信使核糖核酸的技术来量化和可视化整体安装的光片图像中对机械信号的分子响应。这在器官水平的图像中提供了细胞级分辨率的分子读数，并保留了分子的空间位置，然后可以与机械环境的空间分布相关联。成像和评估3D分子图像的工作流程在其他领域有广泛的应用。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This award supports a research program to study how cells behave as limbs are formed. Cells in the body sense and respond to their mechanical environment. The skeletal system is particularly responsive to mechanical loads; muscles, bones, and tendons become stronger with increased mechanical demand. This project will explore how cells sense and respond to the mechanical environment during limb regeneration in an axolotl salamander. During limb regeneration a mass of stem cells forms at the site of amputation. The cells grow and turn into cartilage. The cartilage grows and ossifies, forming functional limbs. Mechanical forces are critical throughout this process. The mechanisms by which cells sense the mechanical environment and how they turn the mechanical stimulus into a biological response will be explored. Understanding how this process works has broad application, such as developing smart materials that adapt to the mechanical environment or developing appropriate physical therapies to correct mechanics and ensure normal growth.This work will help to elucidate the role of mechanics during limb growth: mechanosensitive calcium signaling in stem cells and chondrocytes, the mechanically triggered ion channels involved, the intracellular location of mechanosensitive yes-associated protein, and the mechanotransduction of the signal into a molecular response. Because this study uses the axolotl as a model system of limb regeneration, we will for the first time be able to assess these processes in vivo and determine the role of mechanics throughout the formation of a limb. We will also develop techniques for quantifying and visualizing the molecular response to mechanical signals in whole-mount light sheet images using fluorescence in situ hybridization, fluorescently labelling the mRNA. This provides molecular readouts at cellular-level resolution in organ-level images and preserves the spatial location of the molecules, which then can be correlated with spatial distribution of the mechanical environment. The workflow for imaging and assessing 3D molecular images has broad application in other areas.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.