The Biomechanics of morphogenesis in the frog

青蛙形态发生的生物力学

• 批准号: 8646938
• 负责人: LANCE A. DAVIDSON
• 金额: $ 28.21万
• 依托单位: UNIVERSITY OF PITTSBURGH AT PITTSBURGH
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-01-01 至 2016-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8646938
• 关键词: Actins; Actomyosin; Adopted; Affect; Age; Architecture; Automobile Driving; Back; Behavior; Biological; Biomechanics; Biomedical Engineering; Biophysics; Cell Shape; Cells; Cellular biology; Complement; Confocal Microscopy; Congenital Abnormality; Coupling; Cytoskeleton; DNA Sequence Rearrangement; Development; Developmental Biology; Dorsal; Elements; Embryo; Engineering; Equilibrium; Event; F-Actin; Failure; Feedback; Future; Gene Expression; Generations; Genetic; Germ Layers; Goals; Grant; Human; Imaging Techniques; Intercalated Cell; Measures; Mechanics; Mesoderm Cell; Microsurgery; Modeling; Molecular; Morphogenesis; Movement; Myosin Type II; Neural Tube Defects; Neural tube; Outcome; Pathway interactions; Pattern; Process; Production; Property; Rana; Regulation; Resistance; Resolution; Role; Shapes; Source; Structure; Techniques; Testing; Tissue Engineering; Tissues; Traction; Variant; Work; Xenopus laevis; base; biophysical techniques; biophysical tools; blastomere structure; cell behavior; cell motility; embryo tissue; feeding; gastrulation; innovation; insight; intercalation; knock-down; meetings; molecular scale; multidisciplinary; physical state; protein complex; protein function; public health relevance; response; success; tool; tumor progression; tumorigenesis

DESCRIPTION (provided by applicant): The goal of this proposal is to apply a multi-scale analysis of the mechanics of convergent extension, identifying biomechanical mechanisms that regulate cell shape and drive mediolateral cell behaviors, establish passive tissue properties such as stiffness as well as active processes that generate forces of extension, and how passive mechanics and active force generating processes are coordinated within the frog embryo. We will use an established toolkit consisting of three elements: 1) the aquatic frog Xenopus laevis for direct modulation of protein function and gene expression; 2) high resolution confocal microscopy to visualize cell behaviors, cytoskeletal dynamics, and tissue architecture; and 3) biophysical methods for applying strains, measuring tissue stiffness and force production. Studies outlined in this proposal will answer: 1) How do embryonic cells use actomyosin to physically generate force, change shape, and direct movement during convergent extension? To understand how movements are physically controlled we will take a "bottom-up" analysis of F-actin in the cortex of mesodermal cells as these cells initiate cell shape changes and adopt mediolateral intercalation behaviors. 2) What are the cell and molecular mechanisms underlying bulk tissue stiffness and tissue elongation forces during convergent extension? Our characterization of stiffness of embryonic tissues during gastrulation and axis extension has revealed both broad regulation of stiffness as the embryo ages as well as precise control over stiffness from one germ layer to the next. We propose to test the role of the physical state of the F-actin cytoskeleton in regulating of tissue stiffness and force-production as dorsal tissues converge and extend. 3) What are the physical mechanisms coordinating cell intercalation and stiffness during convergent extension? We hypothesize that gastrulation relies on a proper balance of forces from the elongating dorsal axis and resistance from surrounding tissues. To test this we propose to construct finite element based models to investigate these interactions and test qualitative predictions of our working models. These models will serve to both demonstrate the plausibility of simple mechanical feed-back mechanisms as well as predict the outcome of experimental manipulations. This work will complement ongoing efforts to identify the molecular regulators of morphogenesis by providing underlying biophysical principles for new hypotheses and bioengineering tools to test them. The significance of our work extends beyond defining the mechanical conditions and forces that convert mediolateral cell intercalation into large-scale convergent extension to allow a more complete understanding of the contribution of tissue mechanics to birth defects, to understand the role of tissue mechanics in oncogenesis, and to provide fundamental physical principles for future tissue engineers.

描述（由申请人提供）：该提案的目的是应用收敛扩展力学的多尺度分析，确定调节细胞形状和驱动中外侧细胞行为的生物力学机制，建立被动组织，例如刚度，例如僵硬的过程，以及产生延伸力的主动过程，以及如何产生被动力学过程，以及在内部的动力构造和有效的锻造过程。我们将使用由三个元素组成的已建立的工具包：1）水生蛙爪诺邦Laevis直接调节蛋白质功能和基因表达； 2）高分辨率共聚焦显微镜可视化细胞行为，细胞骨架动力学和组织结构； 3）用于应用菌株，测量组织刚度和力产生的生物物理方法。该提案中概述的研究将回答：1）胚胎细胞如何使用肌动蛋白在收敛延伸过程中生理产生力，改变形状和直接运动？为了了解运动如何受到身体控制，我们将在中胚层细胞皮层中对F-肌动蛋白进行“自下而上”分析，因为这些细胞会启动细胞形状变化并采用中外侧插入行为。 2）在收敛延伸过程中，散装组织刚度和组织伸长力的细胞和分子机制是什么？我们对胃组织和轴伸展过程中胚胎组织刚度的表征既显示了刚度的广泛调节，也表明了胚胎年龄的刚度以及对刚度从一个生殖层到另一个生殖层的刚度的精确控制。我们建议测试F-肌动蛋白细胞骨架的物理状态在调节组织刚度和力产生时，随着背组织的融合和延伸。 3）在收敛延伸过程中协调细胞插入和刚度的物理机制是什么？我们假设胃肠液依赖于伸长背轴和周围组织的耐药性的适当平衡。为了测试这一点，我们建议构建基于有限元的模型，以研究这些相互作用并测试我们工作模型的定性预测。这些模型将既证明简单的机械饲料机制的合理性，又可以预测实验操作的结果。这项工作将通过为新假设和生物工程工具提供基本的生物物理原理，以补充持续的努力，以确定形态发生的分子调节剂来测试它们。我们工作的重要性扩展到定义机械条件和力的力，这些机械条件和能力将中外侧细胞插入转化为大规模的收敛扩展，从而使对组织力学对出生缺陷的贡献有了更完整的了解，以了解组织力学在肿瘤发生中的作用，并为未来的组织工程师提供基本的物理原理。