Developmental Mechanisms of Vestibular Maculae Patterning in Mouse

小鼠前庭黄斑模式的发育机制

基本信息

批准号：
8196736
负责人：
MICHAEL R DEANS
金额：
$ 15.88万
依托单位：
JOHNS HOPKINS UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2009
资助国家：
美国
起止时间：
2009-12-01 至 2012-11-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8196736
关键词：
Address Alleles Amino Acids Animals Apical Architecture Auditory Behavioral Cell Polarity Cell surface Cells Cellular Assay Characteristics Cochlear duct Cues Cytoplasmic Tail DNA Sequence Detection Development Ear Embryo Epithelial Cells Epithelium Equilibrium Event Frequencies Functional disorder Genes Genetic Hair Cells Hearing Kinocilium Knock-out Knockout Mice Labyrinth Mechanics Mediating Morphogenesis Motion Movement Mus Mutant Strains Mice Mutation Neural Tube Defects Organ of Corti Outcome Pattern Phenotype Physiological Process Production Proteins Reporting Research Proposals Saccule and Utricle Sensory Series Signal Transduction Staging Stereocilium Surface Tail Technology Testing Therapeutic Tissues Transgenic Organisms Transmembrane Domain Utricular macula Vestibular Hair Cells age related base critical period deafness design ear sensory receptor equilibration disorder macula meetings motion sensitivity mutant novel public health relevance research study response sound

项目摘要

DESCRIPTION (provided by applicant): The senses of hearing and balance are mediated by the hair cells of the inner ear, sensory epithelial cells with specialized architectures optimized for the detection of movement. Hair cells detect motion via the mechanical deflection of a kinocilium and stereocilia bundle located at one edge of the apical cell surface. Only movements of the bundle towards the kinocilium generate an excitatory response. Consequently the proper polarization of the stereocilia bundle and coordination of bundle polarity between adjacent cells is necessary for accurate vestibular function. Auditory hair cells within the organ of Corti detect sound in a similar fashion and the bundle polarity of adjacent cells is also coordinated. This type of organization is called planar cell polarity (PCP) and has been described in a number of different tissues and species. Moreover, hair cells within the vestibular maculae are further organized into two groups with opposite bundle polarities patterned about an abrupt line of polarity reversal (LPR). This increases the range of detectable motion and sensitivity to motion in a single direction. However, despite the likely importance of stereocilia bundle polarity and hair cell patterning for vestibular function it is not known how bundle polarization is initiated and coordinated within the sensory epithelia. Within this research proposal the cellular mechanisms guiding the polarization of the stereocilia bundle and orientation of hair cells will be evaluated using a combination of transgenic, mutant and knockout mice. [The function of the essential polarity gene van gogh-like2 (vangl2) will be determined by analyzing hair cell PCP using a novel vangl2 knockout mouse (vangl2TMS). These results will be compared to the vangl2 mutant line looptail which has become a reference for inner ear PCP mutant analysis despite having semi-dominant phenotypic characteristics.] Next the cellular mechanism of Vangl2 function in coordinating bundle polarity between adjacent cells will be tested through the production and analysis of a vangl2 conditional knockout line (vangl2floxedATG) in which the polarity gene is deleted in a cell-specific manner. These experiments will determine whether polarity cues are propagated from cell to cell and whether vangl2 is necessary for initiating bundle polarity or maintaining bundle polarity during inner ear morphogenesis. In addition, other vangl2 mutations result in embryonic lethality and this will be avoided be generating ear-specific vangl2floxedATG conditional knockouts. These mice will enable a series of behavioral experiments to examine the effects of hair cell misorientation on vestibular and auditory function. PUBLIC HEALTH RELEVANCE: Project Narrative The proper morphogenesis and organization of specialized inner ear sensory receptors called hair cells is necessary for hearing and balance, and the loss of these cells is the primary basis of age-related deafness and balance disorders. This project is designed to determine how hair cells are oriented and patterned within the within the vestibular maculae of the utricle and saccule. Understanding these events should reveal the basis of some forms of vestibular dysfunction and will define critical parameters that must be met by therapeutic approaches that rely upon introducing replacement hair cells into the mature inner ear.

描述（由申请人提供）：听觉和平衡感由内耳的毛细胞、具有针对运动检测而优化的专门结构的感觉上皮细胞介导。毛细胞通过位于顶端细胞表面一侧边缘的动纤毛和静纤毛束的机械偏转来检测运动。只有束向动纤毛的运动才会产生兴奋反应。因此，静纤毛束的正确极化和相邻细胞之间束极性的协调对于准确的前庭功能是必要的。柯蒂氏器内的听觉毛细胞以类似的方式检测声音，并且相邻细胞的束极性也得到协调。这种类型的组织称为平面细胞极性（PCP），并且已在许多不同的组织和物种中得到描述。此外，前庭黄斑内的毛细胞进一步组织成两组，具有相反的束极性，围绕极性反转突变线（LPR）排列。这增加了可检测运动的范围以及对单个方向运动的敏感度。然而，尽管静纤毛束极性和毛细胞模式对于前庭功能可能很重要，但尚不清楚束极化在感觉上皮内是如何启动和协调的。在这项研究提案中，将使用转基因、突变和敲除小鼠的组合来评估引导静纤毛束极化和毛细胞定向的细胞机制。 [重要极性基因 van gogh-like2 (vangl2) 的功能将通过使用新型 vangl2 敲除小鼠 (vangl2TMS) 分析毛细胞 PCP 来确定。这些结果将与 vangl2 突变系 Looptail 进行比较，后者尽管具有半显性表型特征，但已成为内耳 PCP 突变分析的参考。]接下来，Vangl2 协调相邻细胞之间束极性的细胞机制将通过vangl2 条件敲除系 (vangl2floxedATG) 的产生和分析，其中极性基因以细胞特异性方式被删除。这些实验将确定极性线索是否从一个细胞传播到另一个细胞，以及在内耳形态发生过程中 vangl2 是否是启动束极性或维持束极性所必需的。此外，其他 vangl2 突变会导致胚胎致死，而通过产生耳特异性 vangl2floxedATG 条件敲除可以避免这种情况。这些小鼠将进行一系列行为实验，以检查毛细胞定向错误对前庭和听觉功能的影响。公共健康相关性：项目叙述称为毛细胞的特殊内耳感觉受体的正确形态发生和组织对于听力和平衡至关重要，这些细胞的丧失是与年龄相关的耳聋和平衡障碍的主要基础。该项目旨在确定椭圆囊和球囊前庭黄斑内毛细胞的定向和模式。了解这些事件应该揭示某些形式的前庭功能障碍的基础，并将定义依赖于将替代毛细胞引入成熟内耳的治疗方法必须满足的关键参数。