Development and afferent regulation of auditory neurons

描述(由申请人提供)：神经元树突的形态和固有特性是专门针对它们的功能的。树突状细胞缺陷与许多神经发育障碍密切相关。在这个提议中，我努力确定脆性X智力低下蛋白(FMRP)在听神经元树突调节中的作用。缺乏FMRP会导致脆性X综合征(FXS)，这是自闭症最常见的遗传性单基因病因，表现为一系列症状，包括智力缺陷和感觉障碍。我建议研究FMRP在脑干双耳回路发育过程中的调节，以及在传入活动和完整性改变后，FMRP在树突形态和生化调节中的作用。我将对鸡的大细胞核(NM)和板层核(NL)进行详细的分析，这是一个研究听觉时间加工的良好动物模型，也是一个易于处理的基因操作系统，并将一些分析扩展到人脑。我将使用免疫印迹和免疫细胞化学来描述FMRP在鸡的NM和NL中的发育情况，并确定FMRP与树突发育和特殊生理特性的时间相关性。我将确定FMRP表达下调如何影响鸡NM和NL神经元树突形态的发育和关键蛋白的表达。将使用时间和空间控制、单个细胞填充、免疫细胞化学和高分辨率共聚焦显微镜的基因操作。我将确定FMRP如何调控鸡NL中依赖传入的树突状细胞重组。我将首先研究传入如何调节FMRP，然后评估FMRP基因敲除对传入树突状结构和生化影响的影响。将使用基因和传入联合操作，以及对固定组织和活组织进行共聚焦和多光子成像。与Kulesza博士合作，我们将开始探索FMRP在人类听觉脑干神经元中的潜在功能，方法是使用免疫细胞化学检测固定的人类脑干切片中FMRP和FMRP结合蛋白的时空分布。总体而言，这些研究将为FMRP对树突分枝的调控和听觉处理神经元的专门特性提供见解，并对脊椎动物神经元发育和疾病病理的机制提供见解。

DESCRIPTION (provided by applicant): Neuronal dendritic morphology and intrinsic properties are specialized for their function. Dendritic defects are strongly associated with numerous neurodevelopmental disorders. In this proposal, I endeavor to identify roles of fragile X mental retardation protein (FMRP) in dendritic regulation of auditory neurons. Absence of FMRP results in fragile X syndrome (FXS), the most frequent inherited monogenetic cause of autism, presenting with a constellation of symptoms that include intelligence deficits and sensory dysfunction. I propose to study FMRP regulation during development of very well characterized binaural circuitry in the brainstem and its role in regulation of dendritic morpholog and biochemistry following changes in afferent activity and integrity. I will conduct detailed analyses in the chicken nucleus magnocellularis (NM) and nucleus laminaris (NL), a well-characterized animal model for studying auditory temporal processing and a tractable system for gene manipulation, and will extend some analyses to human brains. I will characterize the developmental profile of FMRP in chicken NM and NL using Western blot and immunocytochemistry, and identify the temporal correlations of FMRP with well-documented characteristics of dendritic development and specialized physiological properties. I will determine how knockdown of FMRP expression affects the development of dendritic morphology and expression of key proteins of chicken NM and NL neurons. Gene manipulations with temporal and spatial control, individual cell filling, immunocytochemistry, and high-resolution confocal microscopy will be used. I will determine how FMRP regulates afferent-dependent dendritic reorganization in chicken NL. I will first examine how afferent regulates FMRP and then assess the effects of FMRP knockdown on afferent influence of dendritic structure and biochemistry. Combined genetic and afferent manipulations, as well as confocal and multi-photon imaging of fixed and live tissues, will be used. In collaboration with Dr. Kulesza, we will start to explore potential function of FMRP in human auditory brainstem neurons by examining the temporal and spatial distribution of FMRP and FMRP-binding proteins in fixed human brainstem sections using immunocytochemistry. Overall, these studies will provide insight into FMRP regulation of dendritic arborization and specialized properties for auditory processing neurons, and insight into mechanisms of vertebrate neuronal development and disease pathology.