Developing branch stress microscopy for the mechanobiology of 3D morphogenesis and invasive diseases

项目概要/摘要 分支结构在发育过程中对于许多器官和腺体的形成是必不可少的。此外，本发明还提供了一种方法， 包括异常血管生成和集体癌症侵袭的许多侵袭性疾病也采取 树枝因此，了解分支的模式和形态发生的机制是 在发育的基础生物学和人类疾病的治疗中至关重要。分支 过程，包括分支的伸长、分叉和终止，可以通过 生物化学信号，如成纤维细胞生长因子和激素。最近的研究还表明， 来自细胞外基质和邻近细胞的信号也影响分支动力学。然而，在这方面， 可能是由于缺乏定量工具，可以测量机械力的分布内， 分支，力学如何调节分支过程仍然没有很好的理解。在这个项目中，我们建议 开发一种新的定量工具，称为分支应力显微镜（BSM），可以精确地映射 分支过程中细胞间机械应力的时空分布。即使有 在过去的几十年里，细胞和组织力学的重大发展，量化了细胞间的力学， 三维空间内的应力仍然是一项具有挑战性的任务。因此，为了管理风险， 项目的设计有两个逐步增加风险和回报的目标。在目标1中，我们将制定一个相对 BSM的简单1D版本，可量化沿形态发生分支的横截面应力沿着。共焦 显微镜将与三维牵引应力计算相结合，以获得总力， 通过力平衡方程在横截面上施加的平均应力。然后我们将验证应力 根据1D BSM计算，与使用3D癌症集体迁移作为 生物模型在目标2中，我们将进一步开发BSM的3D版本，以解决完整的 分支段内细胞间应力的三维分布。我们将进行必要的测量， 关于分支材料特性和在边界处的应力或位移值的假设 分支分段，将问题转化为固体力学中的边值问题。然后我们将计算 利用有限元法分析了癌组织内的应力分布，并验证了假设 以及通过与现有技术测量的应力进行比较来确定工具的坚固性。总之， 该项目将联合收割机在计算机和体外工程和生物学方法，以开发一种新的 该定量工具可广泛适用于体外、离体甚至体内的任何分支过程，因此 为发育和疾病中的机械生物学分支提供了一种通用技术。

PROJECT SUMMARY/ABSTRACT Branched structures are essential for the formation of many organs and glands during development. In addition, many invasive diseases including abnormal angiogenesis and collective cancer invasion also take the form of branches. Hence, understanding the mechanism underlying the patterning and morphogenesis of branches is of critical importance in both fundamental biology of development and treatment of human diseases. Branching processes, including the elongation, bifurcation, and termination of the branches, can be regulated by biochemical signals, such as fibroblast growth factors and hormones. Recent work also suggests that mechanical signals from the extracellular matrix and from neighboring cells also influence branching dynamics. However, likely due to the lack of quantitative tools that can measure the distribution of mechanical forces within the branches, how mechanics regulates the branching process is still not well understood. In this project, we propose to develop a novel quantitative tool, termed branch stress microscopy (BSM), that can precisely map the spatiotemporal distribution of intercellular mechanical stresses during the branching process. Even with significant developments in cell and tissue mechanics over the past decades, quantifying intercellular mechanical stresses within a three-dimensional space remains a challenging task. Hence, to manage the risk, the proposed project is designed with two progressively riskier and more rewarding aims. In Aim 1, we will develop a relatively simple 1D version of BSM that quantifies the cross-sectional stress along a morphogenetic branch. Confocal microscopy will be combined with a three-dimensional traction stress calculation to obtain the total force and average stress exerted at the cross section via force balance equations. We will then validate the stress calculated from 1D BSM against that from the current state of the art using 3D cancer collective migration as a biological model. In Aim 2, we will take one step further to develop a 3D version of BSM to resolve the complete 3D distribution of intercellular stresses within a branch segment. We will make necessary measurements and assumptions regarding the branch material properties and stress or displacement values at the boundary of the branch segment and turn the task into a boundary value problem in solid mechanics. We will then calculate the stress distribution within invading cancer branches using finite element analysis and validate the assumptions and the robustness of the tool by comparing with the stresses measured by the current state of the art. In sum, this project will combine in silico and in vitro engineering and biological approaches to develop a novel quantitative tool that may be widely applicable to any branching processes in vitro, ex vivo and even in vivo, thus providing a versatile technology for branching mechanobiology in development and diseases.