Synaptic Specializations in Auditory Hair Cells

听觉毛细胞的突触专门化

• 批准号: 9043021
• 负责人: Anthony J Ricci
• 金额: $ 47.21万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-12-08 至 2020-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9043021
• 关键词: Address; Aging; Auditory; Biochemical; Biological Assay; Calcium; Cell membrane; Cells; Cochlea; Cochlear nucleus; Complex; Coupled; Electric Capacitance; Electrophysiology (science); Ensure; Fiber; Frequencies; Functional disorder; Funding; Glutamates; Goals; Hair Cells; Health; Hearing; Hereditary Disease; Homeostasis; Human; Image; In Situ; Inner Hair Cells; Intervention; Lasers; Life; Ligase; Measurement; Measures; Mechanics; Mediating; Metabolic; Methods; Mitochondria; Molecular; Molecular Genetics; Monitor; Mus; Neuraxis; Noise; OTOF gene; Optics; Organ; Pathway interactions; Phosphorylation; Play; Post-Translational Protein Processing; Process; Proteins; Pump; Recycling; Regulation; Role; Ryanodine; Signal Transduction; Site; Smooth Endoplasmic Reticulum; Speed; Synapses; Synaptic Transmission; Synaptic Vesicles; Technology; Time; Ubiquitination; Vesicle; age related; base; calmodulin-dependent protein kinase II; computerized tools; genetic manipulation; hearing impairment; new technology; postsynaptic; presynaptic; receptor; research study; response; reuptake; ribbon synapse; sensor; sound; temporal measurement; tool; trafficking; vibration

 DESCRIPTION (provided by applicant): All auditory information received by the central nervous system is transferred across the inner hair cell - afferent fiber synapse. Dysfunction of this synapse due to aging, noise or genetic disorders reduces hearing dramatically. This remarkable synapse must transfer intensity and timing information faithfully for long periods of time. Ribbon synapses, like those in hair cells, are typically found in cells that use graded receptor potentials and need to have sustained release. The hair cell ribbon synapse is more robust than most, releasing at higher rates and sustaining release for longer periods of time. In order for synapses to operate in this manner they must have a robust means of recycling and replenishing vesicles to synaptic release sites. We have identified a nonlinear calcium dependent capacitance change that we hypothesize is a reflection of vesicle recruitment and replenishment. Our first major goal (Aim 1) is to determine whether this nonlinear change is in fact synaptically based and we will do that using paired recordings to identify a postsynaptic response, using a new glutamate sensor to determine if glutamate release mimics the capacitance response and by inactivating ribbons optically to see if we can ablate this nonlinear component. We have also identified a calcium induced calcium release process (CICR) associated with the nonlinear capacitance change. We are hypothesizing that vesicle trafficking is calcium dependent and that CICR is used as a means of ensuring continual vesicle supply while calcium at the synapse is tightly regulated. We will use optical, electrophysiological and immunocytochemical tools to investigate this possibility in aim 2. Otoferlin is a unique protein implicated to regulate vesicle fusion, trafficking and reuptake. We are postulating that biochemical modification of this protein via phosphorylation by CaM Kinase II or ubiquitination is responsible for targeting these different functions. We will investigate this hypothesis using electrophysiological, optical, molecular and immunocytochemical technologies.

 描述（由申请人提供）：中枢神经系统接收的所有听觉信息都通过内毛细胞-传入纤维突触传递。由于年龄、噪音或遗传疾病导致的突触功能障碍会显著降低听力。这个非凡的突触必须长时间忠实地传递强度和时间信息。带状突触，如毛细胞中的那些，通常在使用分级受体电位的细胞中发现，并且需要持续释放。毛细胞带状突触比大多数突触更健壮，以更高的速率释放，并在更长的时间内持续释放。为了使突触以这种方式运作，它们必须有一种强大的手段来回收和补充突触释放位点的囊泡。我们已经确定了一个非线性的钙依赖性电容的变化，我们假设是一个反映囊泡的招聘和补充。我们的第一个主要目标（Aim 1）是确定这种非线性变化是否实际上是基于突触的，我们将使用配对记录来识别突触后反应，使用新的谷氨酸传感器来确定谷氨酸释放是否模仿电容反应，并通过光学灭活丝带来观察我们是否可以消融这种非线性成分。我们还确定了一个钙诱导的钙释放过程（CICR）与非线性电容变化。我们假设囊泡运输是钙依赖性的，CICR被用作确保囊泡持续供应的一种手段，而突触处的钙受到严格调控。我们将使用光学，电生理和免疫细胞化学的工具来研究这种可能性在目标2。Otoferlin是一种独特的蛋白质，参与调节囊泡融合，运输和再摄取。我们推测，通过CaM激酶II磷酸化或泛素化对该蛋白进行的生化修饰负责靶向这些不同的功能。我们将使用电生理学、光学、分子和免疫细胞化学技术来研究这一假说。