In toto Image Analysis of Tissue Mechanics during Vertebrate Ear Development

描述(由Candiate提供)：在脊椎动物耳朵形态发生过程中的组织力学图像分析中，了解耳朵发育是开发早/晚发型耳聋临床疗法的关键，无论是遗传还是环境病因。这项拟议的研究的目标是确定模式回路在脊椎动物耳朵发育中的机械贡献。我的重点是耳泡组织的形态发生，它在负责听力和平衡的专门器官的产生中起着基础性的作用。耳囊由最初增厚的外胚层胎盘发育而来，被诱导形成一个充满内淋巴的皮下中空上皮化外壳。这项拟议的研究使用斑马鱼模型系统，并解决了三个基本问题：(A)耳部组织如何从一片新招募的耳部胎盘细胞转变为具有特定组织/细胞形态的径向极化的上皮组织(B)内淋巴压力在驱动耳部囊泡生长到合适的形状/大小方面起什么作用？因此，沿耳泡周长可观察到由细胞数量和局部细胞形状的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相平衡？为了解决这些问题，提出了以下三个目标：(1)我建议用荧光记者进行全息成像，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囊形成的胎盘细胞的位置、轨迹和细胞分裂，并了解耳胎盘细胞如何从外胚层组织中剥离并重新排列成放射状极化的中空组织。(2)我将用有限元方法将耳囊模拟为“加压壳”，以了解耳囊生长的组织力学。有限元细胞模型将揭示内淋巴分泌的重排力如何驱动组织形状变化。(3)将模型与图案化功能相结合 跨上皮运输和细胞间黏附的基因。通过使用生物物理模型，我 将通过改变细胞-细胞黏附蛋白的表达和内淋巴压力来测试药物和遗传扰动(突变体+变异体)的模型结果。这些扰动将展示细胞水平上的图案化电路如何控制形态发生过程的特定方面。总之，这些目标将阐明模式输入如何通过控制内淋巴分泌和时空黏附蛋白表达来协调耳朵形态发生的细胞学机制。

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.