Investigating the physical mechanisms that drive multicellular lumen morphogenesis

项目总结 组织如何呈现其正确的形状和拓扑结构是一个直接相关的核心生物学问题 对胚胎发育和人类疾病都有影响。这个项目将阐明基本的物理学。 固体细胞团形成中心腔的机制，称为管腔。管腔形成 在早期胚胎发育和器官发生过程中反复出现，并定义了两个功能上的“内部” 以及相关组织的物理形状。以前的工作已经建立了许多 上皮极性和新生管腔生成的遗传和生化要求。然而， 管腔的形成本质上是一个物理过程--从固体细胞团转变为中空的球形细胞团 壳。由于之前的技术限制，令人惊讶的是，人们对生物物理机制知之甚少 推动管腔编队。为了解决这一知识鸿沟，该项目将结合定量生物物理学 用经典细胞生物学方法进行测量以确定基本的物理机制 驱动Madin Darby犬肾上皮细胞管腔形成和扩张的标准 在现场做模特。初步数据表明，与预期相反，细胞可以形成多个初始 开口，表明管腔的形成经历了两个阶段：起始，定义为AT的形成 至少一个小的开口，然后建立，生长和稳定的单个中央管腔。 最近的研究表明，人类胚胎干细胞(HESCs)在适当的3D培养条件下形成 中空球与前羊膜腔有惊人的相似之处，而前羊膜腔是启动 身体计划。在本项目的第二部分中，我将使用使用MDCK改进的实验方法 用于确定人类胚胎干细胞管腔形成物理机制的模型系统。这项工作将 确定在这两个系统中控制管腔形成的物理过程是否反映了不同的 生物起源和功能，从根本上说是相似的或不同的。此外，这些后一种实验 提供对推动早期人类胚胎发育的物理机制的洞察，这不是别的 由于不可避免的技术和道德障碍而无法进入。

PROJECT SUMMARY How tissues assume their correct shape and topology is a central biological question with immediate relevance to both embryonic development and human disease. This project will elucidate the fundamental physical mechanisms by which solid cell masses form a central cavity, termed a lumen. Lumen formation occurs repeatedly during both early embryonic development and organogenesis, and defines both a functional “inside” and “outside” as well as the physical shape of the associated tissue. Previous work has established many of the genetic and biochemical requirements for epithelial polarity and de novo lumen generation. However, lumen formation is an intrinsically physical process – the transition from a solid cell mass to a hollow, spherical shell. Due to previous technical limitations, surprisingly little is known about the biophysical mechanisms that drive lumen formation. To address this knowledge gap, this project will combine quantitative biophysical measurements with classical cell biological approaches to determine the fundamental physical mechanisms that drive lumen formation and expansion in Madin Darby Canine Kidney (MDCK) epithelial cells, a standard model in the field. Preliminary data indicate that, contrary to expectation, cells can form multiple initial openings, suggesting that lumen formation occurs over two stages: initiation, defined as the formation of at least one small opening, followed by establishment, the growth and stabilization of a single central lumen. Recent work has revealed that human embryonic stem cell (hESCs) under proper 3D culture conditions form hollow spheres with striking similarities to the proamniotic cavity, a lumen that is essential for the initiation of the body plan. In the second part of this project, I will use the experimental approach refined using the MDCK model system to determine the physical mechanism of lumen formation employed by hESCs. This work will determine if the physical processes that govern lumen formation in these two systems, which reflect distinct biological origins and functions, are fundamentally similar or different. In addition, these latter experiments provide insight into the physical mechanisms that drive early human embryogenesis, which is not otherwise accessible due to unavoidable technical and ethical barriers.