Determining the Role of Extracellular Matrix Compliance and Composition on Facial Morphogenesis

项目总结 面部形态发生涉及面部原基的定向生长，直到它们与之相对并与之融合。 又一个。目前，原基的生长被认为主要是由块状组织移位驱动的。 由间充质组织中的增殖梯度引起。然而，我们的实验室和其他人已经发现了其他 机制，如定向细胞迁移和上皮引导生长，可能也起到了作用。在 肢芽，由外胚层产生的张力已被证明指导细胞的定向和生长， 如果不结合，整个肢芽的增殖梯度就不能准确地模拟形态发生 定向的细胞行为。我们的实验室之前已经表明，面部的间充质细胞是极化的， 成纤维细胞生长因子(成纤维细胞生长因子)信号的激活破坏了这种极性，同时导致了异常的突起 原基的一部分。细胞周围的细胞外基质(ECM)提供了所需的结构支架 在组织中产生和引导力量，而上皮中的ECM可能引导或抑制局部生长。 我推测，ECM通过成分和组织的区域差异来引导面部的形态发生 合规性。我将通过两个主要目标来检验这一假设。在第一个目标中，我将研究成纤维细胞生长因子信号如何影响 面原基中细胞外基质的物理特性和细胞组织。我将定量地绘制出 共聚焦显微镜和原子力研究面部细胞外基质蛋白组成和细胞外基质顺应性 然后，将这些测量中的地区差异与面部形状的变化联系起来。这一目标将阐明 成纤维细胞生长因子分子信号通过细胞外基质调控形态发生的机制 和蜂窝组织。在第二个目标中，我将通过改变直接增加或减少组织的顺应性 胶原蛋白交联，然后重复与第一个目标相同的分析。第二个目标将决定ECM是否 当间充质被动地围绕着它或有反馈时，僵硬直接指导生长。 细胞外基质和主动重塑环境以指导生长的细胞之间的关系。面部原基衰竭 对位和融合会导致面部裂隙。了解ECM在定向生长中的作用对于 了解面部出生缺陷的病因。

PROJECT SUMMARY Facial morphogenesis involves directed outgrowth of the facial primordia until they appose and fuse with one another. Currently, outgrowth of primordia is considered to be driven primarily by bulk tissue displacement caused by proliferation gradients in the mesenchymal tissue. However, our lab and others have found that other mechanisms, such as directed cellular migration and epithelium guided growth, likely contribute as well. In the limb bud, tensile forces generated by the ectoderm have been shown to direct cellular orientation and growth, and proliferation gradients across the limb bud cannot accurately model morphogenesis without incorporating directed cellular behaviors. Our lab has previously shown that mesenchymal cells in the face are polarized and that activation of fibroblastic growth factor (FGF) signaling disrupts this polarity while causing aberrant outgrowth of the primordium. The extracellular matrix (ECM) around cells provides the structural scaffolding required to generate and guide force through tissue, and the ECM in the epithelium may guide or constrain growth regionally. I hypothesize that the ECM directs morphogenesis in the face via regional differences in composition and compliance. I will test this hypothesis with two main aims. In the first aim I will examine how FGF signaling affects ECM physical properties and cellular organization in the facial primordium. I will quantitatively map the composition of ECM proteins and ECM compliance across the face with confocal microscopy and atomic force microscopy, then relate regional differences in these measures to facial shape change. This aim will elucidate mechanisms by which molecular signaling of fibroblastic growth factor controls morphogenesis through the ECM and cellular organization. In the second aim, I will increase or decrease tissue compliance directly by altering collagen crosslinking, then repeat the same analyses as the first aim. The second aim will determine if ECM stiffness directs outgrowth directly while the mesenchyme passively conforms around it, or if there is feedback between ECM and cells that actively remodel the environment to direct growth. Failure of the facial primordium to appose and fuse leads to facial clefting. Understanding the role of ECM in directional growth is important for understanding the etiology of birth defects in the face.