Planar Polarity Mechanisms in Mammalian Inner Ear Development

哺乳动物内耳发育中的平面极性机制

• 批准号: 10063822
• 负责人: MICHAEL R DEANS
• 金额: $ 32.41万
• 依托单位: UNIVERSITY OF UTAH
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-09-25 至 2023-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10063822
• 关键词: Acceleration; Address; Anatomy; Apical; Articular Range of Motion; Auditory; Biological Assay; Birth; Candidate Disease Gene; Cell Differentiation process; Cell physiology; Cell surface; Chick; Detection; Development; Disease; Dorsal; Embryo; Ensure; Epithelial; Equilibrium; Event; Force of Gravity; Gene Expression; Gene Expression Profiling; Genes; Genetic Models; Genetic Transcription; Goals; Grant; Growth; Hair Cells; Impairment; Individual; Inner Hair Cells; Instruction; Kinocilium; Knockout Mice; Labyrinth; Lateral; Mechanics; Medial; Mediating; Molecular; Morphogenesis; Morphology; Motion; Movement; Mus; Neocortex; Organ; Otic Vesicle; Pathway interactions; Pattern; Peripheral; Physiological; Positioning Attribute; Posture; Process; Proteins; Regulator Genes; Research; Role; SHH gene; Saccule and Utricle; Saccule structure; Sensory; Sensory Hair; Sensory Receptors; Series; Shapes; Side; Signal Pathway; Signal Transduction; Spatial Distribution; Supporting Cell; System; Testing; Therapeutic; Therapeutic Intervention; Transgenic Mice; Utricle structure; Utricular macula; Vestibular Hair Cells; WNT Signaling Pathway; base; body system; design; emx2 protein; equilibration disorder; expectation; experimental study; falls; gene function; hair cell regeneration; hedgehog signal transduction; inner ear development; macula; meetings; morphogens; mouse development; mouse model; mutant; overexpression; planar cell polarity; repaired; response; smoothened signaling pathway; sound; targeted treatment; transcription factor; transcriptome sequencing

Project Summary: In the vestibular system of the inner ear, motion is detected via the mechanical deflection of a bundle of stereocilia located at the top of sensory receptor hair cells. The bundle is morphologically and physiologically polarized because only movements of the bundle towards a lone kinocilium positioned at one side of the apical cell surface are able to produce excitatory responses to acceleration or gravity. Thus the range of motion that can be detected by an individual hair cell is determined by the polarized orientation of the stereociliary bundle. As a result, in order to generate a sensory representation encompassing the broadest possible range of motions, the utricle and saccule contain thousands of vestibular hair cells arranged in radiating arrays spanning a 360⁰ range of bundle orientations. This is achieved in part by dividing the hair cells between two groups separated by a Line of Polarity Reversal (LPR) that have opposing stereocilia bundle orientations and respond to motion in opposite directions. Our goal is to identify the cellular and molecular mechanisms that direct the development of planar polarity and underlie the formation of a sensory representation of gravity and acceleration in the vestibular maculae. This will be addressed through the course of the project using combinations of knockout and transgenic mouse models. Specifically, we will test a hypothesis developed during the first cycle of this grant that two key features organizing planar polarity are established earlier in development than previously expected, and within the otic vesicle. The first of these features is a polarity axis determined by the asymmetric distribution of core PCP proteins in hair cells and supporting cells. Since the formation of this axis is dependent upon the SHH signal transduction molecule Smoothened, we will undertake a series of experiments to determine the mechanisms by which SHH guides planar polarity, distinguishing between instructive and permissive roles. The second feature is a transcriptional boundary established by the transcription factor Emx2 that upon maturation is correlated with the position of the LPR and necessary for its formation. We propose that the emergence of an Emx2 boundary in the otic vesicle precedes formation of the LPR and therefore will identify mechanisms guiding Emx2 expression at early stages of development. Finally, we will determine the mechanisms that allow intercellular PCP signaling and transcriptional boundaries to be maintained throughout morphogenesis in order to understand how these early patterning events might be carried through to the mature sensory organs. Although focused on the development of vestibular planar polarity, we anticipate that this research will impact our understanding of auditory planar polarity as well as other organ systems that rely upon cellular polarization for growth or function.

项目摘要： 在内耳的前庭系统中，通过机械挠度检测到运动 位于感觉受体毛细胞的顶部是形态和生理上的 极化效应，因为位于顶部侧面的孤立核心的洋运动 细胞表面能够产生对加速度或重力的兴奋反应。 可以通过单个毛细胞细胞检测到通过立体束的极化方向确定。 作为ARRT，为了生成一个感官代表包含最广泛可能的动作范围， Utrict和Saccule包含成千上万的前庭毛细胞，这些细胞排列在跨度为360⁰的阵列中 捆绑包的范围是通过潜水来部分疼痛的。 通过一条极性逆转（LPR），具有相反的steocilia捆绑方向并在 相反的方向。 我们的目标是确定指导平面极性发展的细胞和分子机制 感官的形成代表了前庭黄斑中的重力和加速度。 通过敲除和转基因鼠标的组合，将通过项目的过程来解决 模型。 组织平面极性的开发比以前的预期更早，并且在OIT中建立 囊泡。 毛细胞中的蛋白质和支持细胞的形成取决于Sheh信号 转导分子平滑，我们将进行一系列经验，以确定由 该吊索指导平面极性，区分启发性和宽容的角色 是由转录因子EMX2建立的转录边界，该边界与成熟时相关。 LPR的位置和其形成所必需的。 在耳囊中，LPR的形成之前，将确定指导EMX2表达的机制 在开发的早期阶段。 以及在整个形态化过程中要维持的转录边界，以了解如何了解这些 早期构图事件可能会延伸到成熟的感觉器官。 前庭平面极性的发展，我们预计这项研究会影响我们的理解 听觉平面极性以及依赖细胞化生长或功能的器官系统。