Molecular mechanisms of auditory nAChR synapse assembly

听觉 nAChR 突触组装的分子机制

基本信息

批准号：
8519408
负责人：
Michele H. Jacob
金额：
$ 42.57万
依托单位：
TUFTS UNIVERSITY BOSTON
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：
2009-09-19 至 2015-08-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8519408
关键词：
Actinin Actins Affect Aging American Antibiotics Architecture Auditory Basilar Papilla Binding Biochemical Biological Assay Birds Brain Calcium-Activated Potassium Channel Cell Line Cells Complementary DNA Complex Confocal Microscopy Coupling Cytoskeletal Proteins Cytoskeleton Development Dominant-Negative Mutation F-Actin Felis catus Frequencies Functional disorder Gene Transfer Hair Cells Hearing Human Immunofluorescence Microscopy Infection Inner Hair Cells Ion Channel Label Labyrinth Lead Length Lesion Link Maps Mediating Membrane Modeling Molecular Molecular Models Muscle Natural regeneration Nerve Neurons Neurotransmitters Nicotinic Receptors Noise Peptides Phenotype Positioning Attribute Precipitation Protein Binding Proteins Recombinant Proteins Recovery Relative (related person)Research Personnel Role Scaffolding Protein Sensorineural Hearing Loss Sensory Hair Sequence Analysis Signal Transduction Specificity Supporting Cell Surface Synapses Synaptic Transmission Synaptic Vesicles Testing Vesicle Viral Vector abstracting adapter protein base calcium-activated potassium channel small-conductance cholinergic gain of function genetic regulatory protein hair cell regeneration hearing impairment human EMS1 protein in vitro testing in vivo insight loss of function molecular modeling novel positional cloning postsynaptic presynaptic receptor restoration scaffold sound synaptogenesis

项目摘要

Abstract: Sensorineural hearing loss affects 30 million Americans. Aging, noise-overexposure, infection and ototoxic antibiotics all lead to sensory hair cell degeneration and permanent hearing loss. Recently, hair cell regeneration and partial function restoration were induced in the mature mammalian inner ear. However, little is known about molecular mechanisms that direct functional synapse assembly in either normal developing or regenerated hair cells. Our planned studies will define these mechanisms in vivo and identify molecules required for synapse assembly and hearing restoration in the deafened inner ear. This multi-investigator collaborative project draws on the complementary expertise of Michele Jacob (molecular mechanisms of neuronal synapse assembly), Yehoash Raphael (sensory hair cell regeneration), and Keith Duncan (ion channel function in sensory hair cells). We will focus on efferent olivocochlear (OC) cholinergic inputs from the brain onto sensory hair cells. OC cholinergic activity regulates the sensitivity and frequency selectivity of hearing. ¿9/10-containing nicotinic acetylcholine receptors (nAChRs) mediate synaptic transmission in hair cells. Further, normal activity requires the functional coupling and close positioning of ¿9/10-nAChRs to small conductance calcium activated potassium channels (SK2). Early SK2 expression is also required for inner hair cell functional maturation and normal exocytotic activity at the afferent presynaptic inputs onto primary auditory neurons that signal sound reception to the brain. Mechanisms that direct the synaptic localization of ¿9/10- nAChRs and SK2 channels are undefined. We predict the molecular organization of the OC synapse based on our identification of key components at neuronal ¿3-nAChR synapses and preliminary findings of shared components at hair cell ¿9/10-nAChR synapses. In Aim1, we will define the core postsynaptic complex of scaffold and cytoskeletal regulatory proteins at avian OC synapses. Aim2 will define the specific adapter proteins that link ¿9/10-nAChRs and SK2 channels to postsynaptic complex components. Aim3 will test the in vivo roles of the adapter proteins in directing ¿9/10-nAChR and SK2 synaptic localization and functional coupling that are essential for normal hearing. We will test the model in avian developing and regenerated hair cells. We will use loss-of-function and gain-of-function strategies and exploit the spontaneous regeneration and reverse genetic, molecular, morphological, biochemical and functional advantages of chick sensory hair cells. Our findings will provide new insights into the molecular organization of nicotinic synapses in both developing and regenerated hair cells. We will identify novel binding partners for ¿9/10-nAChRs and SK2 channels. Further, the studies will provide the first identification of molecular interactions, in vivo, that are essential for synapse assembly and hearing recovery in the deafened inner ear.

抽象的：感音神经性听力损失影响着 3000 万美国人，其中包括衰老、过度暴露于噪音、感染和耳毒性。抗生素都会导致感觉毛细胞变性和永久性听力损失。成熟哺乳动物内耳的再生和部分恢复功能被诱导，但效果甚微。已知在正常发育或正常发育过程中指导功能性突触组装的分子机制我们计划的研究将在体内定义这些机制并识别分子。失聪内耳的突触组装和听力恢复所需的。合作项目利用了 Michele Jacob 的互补专业知识（分子机制）神经元突触组装）、Yehoash Raphael（感觉毛细胞再生）和 Keith Duncan（离子感觉毛细胞中的通道功能）我们将重点关注来自橄榄耳蜗（OC）的传出胆碱能输入。 OC 胆碱能活性调节大脑对感觉毛细胞的敏感性和频率选择性。听力。含有 9/10 的烟碱乙酰胆碱受体 (nAChR) 介导头发中的突触传递此外，正常活动需要 ¿ 的功能耦合和紧密定位。 9/10-nAChR 变小电导钙激活钾通道 (SK2) 的早期表达也是内毛所必需的。初级听觉传入突触前输入处的细胞功能成熟和正常胞吐活动向大脑发出声音接收信号的神经元，指导 ¿ 的突触定位。 9/10- nAChR 和 SK2 通道未定义，我们根据以下信息预测 OC 突触的分子组织。我们对神经关键组件的识别 ¿ 3-nAChR 突触和共享的初步发现毛细胞的成分 ¿在 Aim1 中，我们将定义 9/10-nAChR 突触的核心突触后复合体。鸟类 OC 突触的支架和细胞骨架调节蛋白将定义特定的接头。连接的蛋白质突触后复合体成分的 9/10-nAChR 和 SK2 通道将测试内部。衔接蛋白在指导中的体内作用 ¿ 9/10-nAChR 和 SK2 突触定位和功能我们将在鸟类发育和再生毛发中测试该模型。我们将使用功能丧失和功能获得策略并利用自发再生和功能。逆转雏鸡感觉毛细胞的遗传、分子、形态、生化和功能优势。我们的研究结果将为发育中烟碱突触的分子组织提供新的见解。和再生的毛细胞。我们将确定 ¿ 的新结合伙伴。 9/10-nAChR 和 SK2 通道。此外，这些研究将首次鉴定体内分子相互作用，这对于聋内耳中的突触组装和听力恢复。