Mechanism and Functional Significance of Polarity Reversal in Mechanosensory Organs

机械感觉器官极性反转的机制和功能意义

基本信息

批准号：
10057376
负责人：
Kathleen E Cullen
金额：
$ 69.83万
依托单位：
JACKSON LABORATORY
依托单位国家：
美国
项目类别：
财政年份：
2019
资助国家：
美国
起止时间：
2019-12-01 至 2024-11-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10057376
关键词：
Ablation Acceleration Address Adopted Adult Affect Age Anatomy Animal Model Anterior Auditory Automobile Driving Behavior Birth Calcium Cell Differentiation process Cell Maturation Cell Polarity Cell physiology Cells Cessation of life Complex Data Development Disease Dizziness Electrophysiology (science)Ensure Epithelial Epithelial Cells Equilibrium Evoked Potentials Eye Movements Fishes Frequencies Functional disorder G-Protein-Coupled Receptors G-substrate GTP-Binding Proteins Genetic Genetic Epistasis Goals Gravity Perception Hair Hair Cells Head Head Movements Hearing Heterotrimeric GTP-Binding Proteins Homologous Gene Image Impairment Intercellular Junctions Ion Channel Labyrinth Lateral Measures Mechanics Mediating Modality Molecular Motion Mus Mutant Strains Mice Organ Orphan Pathway interactions Pattern Pertussis Toxin Phenocopy Physiology Population Positioning Attribute Process Proteins Research Role Saccule and Utricle Saccule structure Sense Organs Sensory Shapes Signal Transduction Sister Stimulus System Testing Time Utricle structure Vertebrates Vision Visual Water Movements Work Zebrafish afferent nerve base behavior test emx2 protein gamma-Aminobutyric Acid gaze innovation insight interest kinetosome lateral line macula mechanotransduction molecular marker mutant nerve supply neuromast planar cell polarity prevent programs public health relevance receptor receptor function regional difference response signal processing therapy design transcription factor vestibulo-ocular reflex virtual water flow

项目摘要

PROJECT SUMMARY/ABSTRACT Vestibular disorders affect as many as 35% of adults past age 40. Studies of the vestibular inner ear have yielded important insights into how we process and compensate for head motion including the existence of parallel channels of information in the afferent nerve. In macular organs, for example, two populations of hair cells adopt opposite planar orientations of their hair bundles and thus opposite responses to head movements. This highly conserved bidirectional organization was first described in neuromasts, the lateral line organs sensing water movements in fish, but the genetic program implementing this reversal during development is only starting to be deciphered. Consequently, ablation studies to reveal the importance of reversal for vestibular function have not been possible until recently. Here we propose to address this question by investigating the consequences of inactivating an orphan G protein coupled receptor (GPCRx), implicated by our preliminary data in orientation reversal in mouse hair cell epithelia. Based on our preliminary data, we suggest that mouse GPCRx functions downstream of the transcription factor EMX2 and upstream of the heterotrimeric G protein Gi to reverse a ground state of polarity established by planar cell polarity proteins. We will test this hypothesis and also use the GPCRx mutant as an animal model to pinpoint how polarity reversal shapes macular organ responses and downstream effects on vestibular behaviors. To reach these goals, we will: 1) Use genetics to determine how GPCRx instructs reversal at the molecular level, solving its epistatic relationship to EMX2, Gi and planar cell polarity proteins in mice, and use zebrafish to test whether GPCRx-Gi is a conserved effector pathway for reversal. 2) Use molecular markers, electrophysiology and calcium imaging to resolve hair cell maturation and function in absence of polarity reversal. 3) Determine how polarity reversal affects afferents' organization and function, with afferent recordings, as well as overall vestibular function using behavioral tests. Our coherent body of preliminary evidence ensures the feasibility and the high interest of the project, and our focus on a virtually unstudied receptor protein guarantees innovation. The multi-PI team is ideally suited to address complementary questions in both the mouse and zebrafish acoustico-lateralis systems. We anticipate that this collaborative effort will be decisive towards solving the mechanism of hair cell orientation reversal, its conservation across vertebrates and its significance for mammalian vestibular physiology. Thorough understanding of polarity reversal will help interpret and design treatments for vestibular dysfunctions.

项目概要/摘要前庭疾病影响多达 35% 的 40 岁以上成年人。对前庭内耳的研究表明对我们如何处理和补偿头部运动（包括头部运动的存在）产生了重要的见解例如，在黄斑器官中，传入神经中存在平行的信息通道。细胞采用相反的发束平面方向，因此对头部运动做出相反的反应。这种高度保守的双向组织首先在神经丘（侧线器官）中被描述感知鱼类的水运动，但在发育过程中实现这种逆转的遗传程序是消融研究才刚刚开始被解读，以揭示逆转的重要性。直到最近，前庭功能才成为可能。在这里，我们建议通过以下方式解决这个问题。研究失活孤儿 G 蛋白偶联受体 (GPCRx) 的后果，涉及我们在小鼠毛细胞上皮细胞方向反转方面的初步数据基于我们的初步数据，我们。表明小鼠 GPCRx 在转录因子 EMX2 下游和转录因子 EMX2 上游发挥作用。异三聚体 G 蛋白 Gi 可逆转平面细胞极性蛋白建立的极性基态。我们将测试这一假设，并使用 GPCRx 突变体作为动物模型来查明极性如何逆转塑造黄斑器官反应和对前庭行为的下游影响以达到这些目的。为了实现目标，我们将：1）利用遗传学来确定 GPCRx 如何在分子水平上指示逆转，解决其问题与小鼠 EMX2、Gi 和平面细胞极性蛋白的上位关系，并使用斑马鱼测试是否 GPCRx-Gi 是一种保守的逆转效应途径 2) 使用分子标记、电生理学和方法。钙成像可解决极性反转情况下毛细胞的成熟和功能问题 3) 确定如何进行。极性反转影响传入的组织和功能，传入记录以及整体我们通过行为测试来确定前庭功能。以及对该项目的高度兴趣，以及我们对几乎未经研究的受体蛋白的关注保证多 PI 团队非常适合解决小鼠和小鼠中的互补问题。我们预计这种合作努力将对斑马鱼外侧声学系统产生决定性影响。解决毛细胞方向反转的机制、其在脊椎动物中的保守性及其意义对于哺乳动物前庭生理学的深入了解将有助于解释和设计。前庭功能障碍的治疗。