Pathogenic events triggered by tau acetylation in neurodegenerative tauopathy

描述（由申请人提供）：Tauopathies是一类与年龄相关的神经退行性疾病，目前我国有数百万人患有这种疾病。tau蛋白病的特征在于tau（一种微管相关蛋白）在脑中的异常积累，其与严重和使人衰弱的认知功能障碍有关。目前有有限数量的治疗选择可用于患有tau蛋白病的人，并且没有治愈方法。确定tau致病作用机制的研究对于寻找药物干预的新分子靶点至关重要。最近的证据表明，乙酰化tau蛋白（ac-tau）可能有助于tau蛋白病的发病机制，但ac-tau蛋白是否影响神经元功能的认知障碍是未知的。我的长期目标是揭示ac-tau在神经退行性tau蛋白病中的作用，为靶向ac-tau蛋白作为治疗认知功能障碍的新策略提供基础。 目的1是确定ac-tau如何影响海马兴奋性突触生理学。具有突变为谷氨酰胺的赖氨酸以模拟特定残基处的乙酰化的人tau构建体（K/Q突变体）将通过基于慢病毒的基因转移在体内小鼠海马神经元中表达。将对神经元进行电生理记录，以检查K/Q突变体对基础兴奋性传递和突触可塑性的突触后效应。来自培养神经元的记录的初步结果显示，tau的微管结合结构域中的K/Q突变体导致突触能突触传递的减少。 目的二是探讨ac-tau对兴奋性突触后功能影响的分子机制。免疫细胞化学和共聚焦显微镜将被用来研究是否ac-tau异常定位在树突棘兴奋性突触。此外，将进行突触后谷氨酸受体的免疫染色以检查K/Q突变体如何调节受体导致突触功能障碍。随后将研究连接ac-tau与突触后谷氨酸受体调节的特定分子相互作用。 目的3是确定ac-tau在体内的致病作用。将产生具有引起突触病理生理学的人tau K/Q突变体的神经元表达的转基因小鼠（tau-K/Q小鼠）。将通过兴奋性突触传递和突触可塑性的电生理学记录来监测tau-K/Q小鼠海马中功能电路的任何异常修饰。行为测试将确定tau-K/Q小鼠是否发展与tau蛋白病相关的学习和记忆缺陷。最后，将对老年tau-K/Q小鼠进行组织学和生物化学分析，以评价脑中的神经变性和tau病理学。总之，该项目的结果将为tau在神经退行性疾病中的致病机制提供重要的见解。

DESCRIPTION (provided by applicant): Tauopathies are a class of age-related neurodegenerative diseases that millions of people in our country suffer from today. Tauopathies are characterized by the abnormal accumulation of tau, a microtubule- associated protein, in the brain which is linked to severe and debilitating cognitive dysfunction. There are currently a limited number of treatment options available for people suffering from tauopathy and there is no cure. Research to identify the mechanisms for the pathogenic effect of tau is crucial to find new molecular targets for drug intervention. Recent evidence suggests that acetylated tau (ac-tau) may contribute to pathogenesis in tauopathy, however whether ac-tau affects neuronal function underlying cognitive impairments is unknown. My long-term goal is to uncover the role of ac-tau in neurodegenerative tauopathy to provide a foundation for targeting ac-tau as a novel strategy to treat cognitive dysfunction. Aim 1 is to determine how ac-tau affects excitatory synaptic physiology in the hippocampus. Human tau constructs with lysines mutated to glutamines to mimic acetylation at specific residues (K/Q mutants) will be expressed in mouse hippocampal neurons in vivo by lentiviral-based gene transfer. Electrophysiological recordings will be performed on neurons to examine the postsynaptic effect of K/Q mutants on basal excitatory transmission and synaptic plasticity. Preliminary results from recordings of cultured neurons show that a K/Q mutant in the microtubule-binding domain of tau causes a reduction in glutamatergic synaptic transmission. Aim 2 is to determine the molecular mechanism for the effect of ac-tau on excitatory postsynaptic function. Immunocytochemistry and confocal microscopy will be used to investigate whether ac-tau is aberrantly localized at excitatory synapses in dendritic spines. Furthermore, immunostaining of postsynaptic glutamate receptors will be done to examine how the K/Q mutants modulate receptors leading to synaptic dysfunction. This will be followed by an investigation of a specific molecular interaction linking ac-tau to the regulation of postsynaptic glutamate receptors. Aim 3 is to establish the pathogenic effect of ac-tau in vivo. A transgenic mouse will be generated with neuronal expression of a human tau K/Q mutant that causes synaptic pathophysiology (tau-K/Q mice). Any abnormal modifications of the functional circuitry in the hippocampus of tau-K/Q mice will be monitored by electrophysiological recordings of excitatory synaptic transmission and synaptic plasticity. Behavioral tests will determine if tau-K/Q mice develop deficits in learning and memory associated with tauopathies. Finally, histological and biochemical analyses will be performed on aged tau-K/Q mice to evaluate neurodegeneration and tau pathology in the brain. Together, the results from this project will provide significant insight into the pathogenic mechanisms of tau in neurodegenerative disease.