Cell-Cell and Cell-Matrix Interactions in Morphogenesis

项目概要/摘要 形态发生是驱动组织组装并阐述组织结构的基本发育过程。 不同的解剖结构共同组成了所有后生动物的身体平面。大多数人类出生缺陷 是由正常形态发生过程的中断引起的。形态发生如何在多个层次上起作用 组织和复杂性是生物学中剩下的关键问题之一，这一领域的进展将是 需要帮助告知工程师更换组织和器官的努力。近三十年来， 一个实验室通过关注细胞运动和组织重排来解决这个问题 负责两栖动物爪蟾的原肠胚形成。我们探索细胞如何粘附到其他细胞和细胞的表面。 细胞外基质（ECM）被调节以促进或稳定原肠胚形成的细胞和组织运动。 钙粘蛋白和整合素粘附复合物是这些过程中的核心参与者，除了它们的一般生物学特性之外， 在保持细胞和组织在一起的作用，他们也感觉，抵抗和分配机械力， 是形态发生的结果我们发现了钙粘蛋白和角蛋白中间体的新功能 在原肠胚形成时中内胚层中的集体细胞迁移的力依赖性调节中， 虽然粘附连接、局部粘附和肌动蛋白细胞骨架对机械感觉的重要性 和机械转导现在已经很好地建立，桥粒和其他中间丝（IF）的作用， 这些过程中的相关连接点在很大程度上被忽视了。这项拨款提案的一个主要目标是 通过关注KIF的功能和KIF的相关性， 细胞骨架与中内胚层中基于钙粘蛋白的粘附。我们假设力的大小 应用于钙粘蛋白可以指导与肌动蛋白或KIF连接的粘附的差异募集和组装， 细胞骨架我们将通过开发新的检测方法来测试这一点，该检测方法旨在将确定的力应用于 单个细胞，并遵循粘附蛋白和桥粒相关连接蛋白的募集，以应激 粘连部位。在相关的实验中，我们还将询问中胚层基因的模式是否随时间而变化。 施加于细胞-细胞和/或细胞-基质粘附的力的大小，可能类似于（和/或 协同作用）细胞感测形态发生素浓度梯度内的位置信息。未来进展 在这些领域的研究也将受益于形态发生运动的计算机模拟的发展。一 合作者团队是基于代理和有限元方法的专家，用于细胞和组织级建模 行为将与我们一起模拟最初的力依赖极化和集体迁移， 中内胚层细胞。我们的长期目标是探索如何将多个区域的模拟集成在一起， 形态发生机器，以获得更好的图片的整体贡献的个人组织运动， 原肠胚形成

Project Summary/Abstract Morphogenesis is the fundamental developmental process that drives tissue assembly and elaborates the diverse anatomical structures that together comprise the body plans of all metazoa. Most human birth defects arise from disruptions in normal morphogenetic processes. How morphogenesis works at multiple levels of organization and complexity is one of the key remaining questions in biology and progress in this area will be needed to help inform efforts to engineer replacement tissues and organs. For nearly three decades our laboratory has approached this problem by focusing on the cell movements and tissue rearrangements responsible for gastrulation in the amphibian Xenopus. We explore how cell adhesion to other cells and to the extracellular matrix (ECM) is regulated to promote or stabilize the cell and tissue movements of gastrulation. Cadherin and integrin adhesion complexes are central players in these processes and aside from their general roles in holding cells and tissues together, they also sense, resist and distribute mechanical forces that arise as a consequence of morphogenesis. We have discovered a novel function for cadherins and keratin intermediate filaments (KIF) in the force-dependent regulation of collective cell migration in the mesendoderm at gastrulation. Although the importance of adherens junctions, focal adhesions and the actin cytoskeleton to mechanosensation and mechanotransduction is now well established, the role of desmosomes and other intermediate filament (IF) associated junctions in these processes has been largely overlooked. A major goal of this grant proposal is to bridge this significant gap in understanding by focusing on KIF functions and the association of the KIF cytoskeleton with cadherin-based adhesions in the mesendoderm. We hypothesize that the magnitude of forces applied to cadherins can direct the differential recruitment and assembly of adhesions linked to the actin or KIF cytoskeletons. We will test this by developing new assays designed to apply defined forces to cadherins on single cells and follow the recruitment of adherens- and desmosomal-associated junctional proteins to stressed adhesion sites. In related experiments we will also ask whether patterning of mesoderm genes varies with the magnitude of forces applied to cell-cell and/or cell-matrix adhesions, perhaps acting analogously to (and/or in synergy with) cells sensing positional information within a concentration gradient of morphogen. Future progress in these areas will also benefit from the development of in silico simulations of morphogenetic movements. A team of collaborators expert in agent-based and finite element methods for modelling cell and tissue-level behaviors will work with us to simulate initially the force dependent polarization and collective migration of mesendoderm cells. Our longer-term goal is to explore ways to integrate simulations of multiple regional morphogenetic machines to gain a better picture of the global contributions of individual tissue movements to gastrulation.