Uncovering New Roles for Mechanical Force in Tissue Development and Remodeling

描述(由申请人提供) 摘要：细胞施加的机械力控制着现代生物学和医学中至关重要的过程，如癌症转移、干细胞分化和胚胎发育。然而，细胞施加和检测力的机制仍然知之甚少。我们对机械信号如何调节整个组织或器官的行为的理解也同样处于初级阶段。我们将使用单分子生物物理学的工具来测试关于机械力在生物学中的作用的变革性假设。目前的技术没有提供细胞内和细胞之间的力的定量测量。我们将使用新的分子力传感器来直接观察活细胞中基于肌球蛋白的张力产生。这些测量将提供一个前所未有的视角，将细胞视为机械实体--我们将实时观察细胞对力的施加和反应。因此，我们的测量从根本上偏离了传统的显微镜形式，这些显微镜表征细胞结构，但对塑造和维持细胞和组织的潜在机械力视而不见。我们的工作将澄清关于细胞骨架如何构建的长期争议，对我们理解干细胞分化和癌症转移具有重要意义。在另一组单独的测量中，我们将测试这一假设，即机械力通过基质金属蛋白酶(MMPs)直接调节细胞外基质的重构。这一模型的确认将为心脏病的研究开辟新的途径。此外，我们的测量将为MMPs区分底物的机制提供关键的见解，从而有助于开发更好的癌症治疗方法。最后，我们将通过测量整个果蝇胚胎中肌球蛋白力的产生和细胞外基质的重塑来整合这两个研究线索。我们在果蝇身上的实验代表了对生物体内分子作用力的产生和机械信号的定量理解的第一步。我们认为，这种向活体测量的过渡代表着我们自己的研究和整个生物物理学领域的一个必要的进步。 与公共健康相关：细胞使用纳米分子马达来移动、生长和分裂。人体内的细胞也会相互拉扯。这种机械信号是正常生长和发育的关键组成部分，但机械通讯的故障可能导致多种疾病的发生。我们将实时观察生物体中的细胞对力的产生和反应。通过更多地了解细胞机械信号是如何工作的，我们将能够更好地理解和治疗癌症、心脏病和其他重要疾病。

DESCRIPTION (Provided by the applicant) Abstract: Mechanical forces exerted by cells control processes of central importance in modern biology and medicine, for example cancer metastasis, stem cell differentiation, and embryonic development. However, the mechanisms by which cells exert and detect force remain poorly understood. Our understanding of how mechanical signaling modulates the behavior of whole tissues or organs is likewise in its infancy. We will use the tools of single-molecule biophysics to test transformative hypotheses about the roles of mechanical force in biology. Current techniques do not provide quantitative measurements of forces within and between cells. We will use novel molecular force sensors to directly observe myosin-based tension generation in living cells. These measurements will provide an unprecedented look at cells as mechanical entities-we will watch cells exert and respond to force in real time. Our measurements thus constitute a radical departure from the traditional forms of microscopy that characterize cellular structure, but that are blind to the underlying mechanical forces that shape and maintain both cells and tissues. Our work will clarify long-standing controversies about how the cytoskeleton is constructed, with important implications for our understanding of stem cell differentiation and cancer metastasis. In a separate set of measurements we will test the hypothesis that mechanical forces directly modulate the remodeling of the extracellular matrix by matrix metalloproteinases (MMPs). Confirmation of this model will open up new avenues in the investigation of heart disease. Further, our measurements will provide crucial insight into the mechanism by which MMPs differentially recognize substrates, thus contributing to the development of improved treatments for cancer. Finally, we will integrate these two strands of inquiry by measuring both myosin force generation and extracellular matrix remodeling in whole Drosophila embryos. Our experiments in Drosophila represent a first step toward a quantitative understanding of molecular force generation and mechanical signaling in living organisms. We feel that this transition to in vivo measurement represents a necessary progression both in our own research and for the field of biophysics as a whole. Public Health Relevance: Cells use nanometer-sized molecular motors to move, grow, and divide. Cells inside the human body also pull and tug on each other. This mechanical signaling is a crucial component of normal growth and development, but failures in mechanical communication can result in to the development of multiple diseases. We will watch cells in living organisms create and respond to force in real time. By learning more about how cellular mechanical signaling works we will be better able to understand and treat cancer, heart disease, and other important illnesses.