Pathogenic events triggered by tau acetylation in neurodegenerative tauopathy

描述（由申请人提供）：牛头病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此病。tau病的特点是大脑中tau蛋白（一种微管相关蛋白）的异常积累，这与严重和衰弱的认知功能障碍有关。目前，对于患有牛头病的人，可供选择的治疗方法有限，而且无法治愈。研究tau蛋白致病机制对寻找新的药物干预分子靶点至关重要。最近的证据表明乙酰化的tau （ac-tau）可能与tau病的发病机制有关，然而，ac-tau是否影响认知障碍的神经元功能尚不清楚。我的长期目标是揭示ac-tau在神经退行性tau病中的作用，为靶向ac-tau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如何影响海马的兴奋性突触生理。通过慢病毒基因转移，将赖氨酸突变为谷氨酰胺以模拟特定残基乙酰化的人tau构建体（K/Q突变体）在小鼠海马神经元中表达。将对神经元进行电生理记录，以研究K/Q突变对基础兴奋性传递和突触可塑性的突触后影响。培养神经元记录的初步结果表明，tau微管结合区域的K/Q突变导致谷氨酸能突触传递减少。目的2是确定ac-tau蛋白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用于研究ac-tau是否异常地定位于树突棘的兴奋性突触。此外，将对突触后谷氨酸受体进行免疫染色，以检查K/Q突变体如何调节受体导致突触功能障碍。这将是随后的一个特定的分子相互作用的研究连接ac-tau突触后谷氨酸受体的调节。目的3是在体内建立ac-tau的致病作用。将产生具有人类tau K/Q突变体的神经元表达的转基因小鼠，引起突触病理生理（tau K/Q小鼠）。tau-K/Q小鼠海马功能电路的任何异常改变都将通过兴奋性突触传递和突触可塑性的电生理记录来监测。行为测试将确定tau-K/Q小鼠是否会出现与tau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化分析，以评估脑内神经变性和tau病理。总之，这个项目的结果将为tau蛋白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.