Development studies of the inner ear

描述（由申请人提供）：我们研究的目标是了解控制发育中内耳模式和细胞命运规范的时间和分子机制。内耳是脊椎动物所特有的，其组成细胞的复杂三维排列是引人注目的，这些细胞包括神经元、感觉受体和非感觉细胞，它们被组织成小管、导管和其他专门组织。很可能脊椎动物也具有形成这种结构所需的形态遗传机制。在人类和动物模型中，由于先天性异常或疾病导致的内耳精确形态的破坏可导致耳聋和/或平衡和平衡困难。我们努力了解导致内耳异常的基本缺陷，重点是正常的发育过程和特定遗传缺陷可能导致的一连串事件。 在本研究中，我们的目的是：（1）进行谱系分析的祖细胞在现成的鸡耳囊，以揭示不同的细胞谱系分化，如感觉与非感觉或神经源性与非神经源性;（2）对小鼠内耳进行谱系分析，以确定毛细胞和支持细胞是否具有共同的祖细胞，以及是否存在细胞谱系。（3）探索Wnt信号传导途径在耳中细胞命运特化中的作用，特别是关于听觉与前庭细胞命运决定。我们的研究将采用复制缺陷型逆转录病毒载体，以限制基因转移到少数耳细胞及其后代。为了研究Wnt，我们将使用可复制的病毒来产生广泛的错误表达，用于功能获得和功能丧失实验。 总之，拟议的研究应该提供关于内耳谱系分歧的见解。我们的研究旨在测试内耳模式的模型，该模型基于耳上皮内的隔室和边界的建立。迄今为止，我们的数据显示，前庭-前庭命运决定可以通过Wnt/β-连环蛋白信号转导来操纵。这些发现和本研究产生的新数据可能为治疗策略提供基线数据，以指导干细胞沿着不同的发育命运，根据感觉器官细胞类型可能需要更换。

DESCRIPTION (provided by applicant): The goal of our research is to understand the timing and molecular mechanisms that control patterning and cell fate specification in the developing inner ear. The inner ear, unique to vertebrates, is remarkable for the complex three-dimensional arrangement of its constituent cells, which include neurons, sensory receptors and non-sensory cells organized into tubules, ducts and other specialized tissues. It is likely that the morph genetic mechanisms required to form such structures will be shared by vertebrates. In humans and animal models, disruption of the precise morphology of the inner ear due to congenital anomalies or disease can result in deafness and/or to difficulties with balance and equilibrium. Our efforts to understand the fundamental defects that result in inner ear abnormalities are focused on both the normal processes of development and on the cascade of events that can arise as a result of a specific genetic defect. In this study, we aim to: (1) undertake lineage analysis of the progenitor cells in the ready chicken otocyst to reveal when distinct cell lineages diverge, such as sensory vs. non-sensory or neurogenic vs. nonneurogenic; (2) undertake lineage analysis in the mouse inner ear to determine whether hair cells and supporting cells share a common progenitor and whether there are cell lineage (compartment) boundaries in the organ of Corti; and (3) explore the role of the Wnt signaling pathway in cell fate specification in the ear, particularly with respect to the auditory vs. vestibular cell fate decision. Our studies will employ replication defective retroviral vectors to limit gene transfer to a small number of otic cells and their progeny. To study the Wnts, we will use replication-competent viruses to generate widespread misimpression for both gain-offunction and loss-of-function experiments. Together, the proposed studies should provide insight on the divergence of inner ear lineages. Our studies are designed to test a model of inner ear patterning that is based on the establishment of compartments and boundaries within the otic epithelium. Our data to date reveal that the auditory-vestibular fate decision can be manipulated through Wnt/b-catenin signaling. These findings, and new data generated from this study, may provide baseline data for a therapeutic strategy to direct stem cells along different developmental fates according to which sensory organ cell types may need to be replaced.