Cell-Cell and Cell-Matrix Interactions in Morphogenesis

项目摘要/摘要 形态发生是驱动组织组装的基本发育过程，并阐述了 不同的解剖结构，共同构成所有后生动物的身体平面。大多数人类先天缺陷 起源于正常形态发生过程的中断。形态发生是如何在多个层次上起作用的 组织和复杂性是生物学剩余的关键问题之一，这一领域的进展将是 需要帮助为设计替代组织和器官的努力提供信息。近三十年来，我们的 实验室通过专注于细胞运动和组织重排来解决这个问题 负责非洲爪哇两栖动物的原肠形成。我们探索了细胞如何与其他细胞以及 细胞外基质(ECM)被调节以促进或稳定细胞和组织的原肠形成运动。 钙粘附素和整合素黏附复合体是这些过程中的核心角色，除了它们的一般 在将细胞和组织结合在一起的过程中，它们还可以感知、抵抗和分配因 形态发生的结果。我们发现了钙粘附素和角蛋白中间体的一种新功能 原肠形成时中胚层集体细胞迁移的力依赖调节中的细丝(Kif)。 尽管粘着连接、焦点粘连和肌动蛋白细胞骨架对机械感觉的重要性 机械转导现在已经确定，桥粒和其他中间丝(IF)的作用。 这些过程中的相关连接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的关联，弥合这一理解上的重大差距 细胞骨架与中胚层中钙粘附素的粘连。我们假设力的大小 应用于钙粘附素可以指导与肌动蛋白或kif相关的粘连的差异性招募和组装。 细胞骨架。我们将通过开发新的分析方法来测试这一点，该方法旨在将定义的力量应用于钙粘素 单个细胞并跟随黏附和桥粒相关连接蛋白的募集来应激 粘连部位。在相关的实验中，我们还会问中胚层基因的模式是否会随着 施加在细胞-细胞和/或细胞-基质粘连上的力的大小，可能作用类似于(和/或在 协同作用)细胞在形态原浓度梯度内感应位置信息。未来的进展 这些地区还将受益于形态发生运动的电子计算机模拟技术的开发。一个 合作者团队精通基于代理的有限元方法，用于细胞和组织级别的建模 Behaviors将与我们合作，初步模拟依赖于力的极化和集体迁移 中胚层细胞。我们的长期目标是探索整合多个区域模拟的方法 形态发生机器以更好地了解单个组织运动对全球的贡献 原肠形成。

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.