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的组织力学图像分析了解耳的发育是开发早期/晚发性耳聋临床治疗的关键，无论是遗传还是环境病因。本研究的目的是确定脊椎动物耳朵发育过程中模式电路的机械作用。我的重点是耳泡组织的形态发生，它在负责听觉和平衡的专门器官的产生中起着重要作用。耳小泡由最初增厚的外胚层发育而成，后被诱导形成皮下充满内淋巴的中空上皮化壳。提出的研究使用斑马鱼模型系统并解决三个基本问题：(A)耳部组织如何从新招募的耳部基板细胞转变为具有特定组织/细胞形态的径向极化上皮组织(B)内淋巴压力在驱动耳部囊泡生长到正确形状/大小中的作用是什么？因此，沿耳泡周长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)内淋巴压力如何与影响细胞/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)我建议使用荧光报告器进行toto成像，以生成形态发生过程的4维细胞描述。通过图像分析，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，了解耳基板细胞如何从外胚层组织剥离并重新排列成径向极化的中空组织。(2)我将把耳泡建模为一个“加压壳”，使用有限元表示来理解耳泡生长的组织力学。一个有限元细胞模型将揭示如何重排力量从内淋巴分泌驱动组织形状的变化。(3)我将模型与图案化功能相结合

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.