In toto Image Analysis of Tissue Mechanics during Vertebrate Ear Development

描述（由候选人提供）：脊椎动物耳形态发生过程中组织力学的整体图像分析了解耳发育是开发早/晚发性耳聋临床治疗的关键，无论是遗传还是环境病因。这项研究的目的是确定脊椎动物耳朵发育中图案电路的机械贡献。我的重点是耳泡组织的形态发生，它在负责听觉和平衡感的专门器官的产生中起着重要作用。耳泡由最初增厚的外胚层基板发育而成，外胚层基板被诱导形成充满内淋巴的皮下中空上皮化壳。所提出的研究使用斑马鱼模型系统并解决三个基本问题：（A）耳组织如何从一片新募集的耳基板细胞转化为具有特定组织/细胞形态的径向极化上皮组织（B）内淋巴压在驱动耳囊泡生长至正确形状/大小中的作用是什么？因此，沿耳泡周边沿着可观察到由细胞数量和局部细胞形状变化引起的大规模组织变化。(C)内淋巴压如何与影响细胞/组织形状的细胞间粘附力和皮质张力平衡？为了解决这些问题，提出了以下三个目标：（1）我建议进行全成像与荧光报告，以产生4维细胞的形态发生过程的描述。通过使用图像分析，我将全面重建参与耳泡形成的基板细胞的位置、轨迹和细胞分裂，并了解耳基板细胞如何从外胚层组织分层并重新排列成径向极化的中空组织。(2)我将使用有限元表示法将耳泡建模为“加压壳”，以了解耳泡生长的组织力学。有限元细胞模型将揭示来自内淋巴分泌的重排力如何驱动组织形状变化。(3)我将把模型与图案化功能结合起来 跨上皮转运和细胞间粘附的基因。通过使用生物物理模型，我 将通过改变细胞-细胞粘附蛋白表达和内淋巴压来测试具有药理学和遗传扰动（突变体+morphant）的模型结果。这些扰动将演示如何在细胞水平上的图案电路控制形态发生过程的特定方面。总之，这些目标将阐明如何图案输入协调耳形态发生的细胞力学通过控制内淋巴分泌和时空粘附蛋白的表达。

DESCRIPTION (provided by candidate): In toto Image Analysis of Tissue Mechanics during Vertebrate Ear Morphogenesis Understanding ear development is key to developing clinical therapies for early/late-onset deafness, whether of genetic or environmental etiology. The goal of the proposed study is to determine the mechanical contribution of patterning circuits involved in vertebrate ear development. My focus is on the morphogenesis of the otic-vesicle tissue, which plays a fundamental role in the generation of specialized organs responsible for the sense of hearing and balance. The otic vesicle develops from an initially thickened ectodermal placode that is induced to form a subcutaneous, hollow epithelialized shell filled with endolymph. The proposed research uses the zebrafish model system and addresses three fundamental questions: (A) How does the otic tissue transform from a sheet of newly recruited otic placode cells into radially polarized epithelial tissue with a specific tissue/cell morphology (B) What is the role of endolymph pressure in driving the growth of the otic vesicle to the right shape/size? As such, large- scale organizational changes arising from changes in cell number and localized cell shape are observable along the otic-vesicle perimeter. (C) How does endolymph pressure equilibrate with intercellular forces of adhesion and cortical tension that affect cell/tissue shape? To address these questions, the following three aims are proposed: (1) I propose to conduct in toto imaging with fluorescent reporters to generate 4-dimensional cellular descriptions of the morphogenesis process. By using image analysis, I will comprehensively reconstruct the locations, tracks, and cell divisions of placode cells involved in otic-vesicle formation and learn how otic placode cells delaminate from ectoderm tissue and rearrange into radially polarized hollow tissue. (2) I will model the otic vesicle as a "pressurize shell" using a finite-element representation to understand tissue mechanics of otic-vesicle growth. A finite-element cell model will reveal how rearrangement forces from endolymph secretion drive tissue shape change. (3) I will integrate the model with the function of patterning genes for transepithelial transport and inter- cellular adhesion. By using the biophysical model, I will test model outcomes with pharmacological and genetic perturbations (mutants+morphants) by altering cell-cell adhesion protein expression and endolymph pressure. These perturbations will demonstrate how patterning circuits at a cellular level control specific aspects of the morphogenesis process. Together, these aims will elucidate how patterning inputs coordinate cell mechanics for ear morphogenesis by controlling endolymph secretion and spatiotemporal adhesion protein expression.