Mechanisms of Susceptibility of Excitatory Neurons to Tau Pathology and Neurodegeneration in Alzheimer's disease

项目摘要 海马对学习和记忆很重要，并且对微管的聚集非常敏感。 相关蛋白tau（MAPT）和神经变性。阿尔茨海默病的海马和新皮质萎缩 (AD)大脑显示变性主要发生在联合皮质中的大海马锥体神经元 而抑制性中间神经元和初级皮质对MAPT积累和退化具有抗性。但 引起易感神经元损伤和死亡的分子机制尚不清楚。开发更好的 了解兴奋性神经元易受损伤的分子机制， 调节tau蛋白介导的神经变性的途径对于阐明发病机制和 AD的进展和识别潜在的治疗靶点。该提案的主要目标是确定 使兴奋性神经元容易受到tau积累和神经退行性变的影响，并确定潜在的治疗方法 AD的目标。一个重要的限制是哺乳动物大脑的细胞异质性。为了克服细胞 异质性，该提案将创新性地使用单细胞RNA测序在新鲜的AD人脑组织和病毒 翻译核糖体亲和纯化（vTRAP），以产生Tau蛋白病的转录谱。 兴奋性和抑制性神经元从脆弱的和有弹性的大脑区域的背景下老化， 神经变性将构建兴奋性和抑制性神经元的全局基因共表达网络 通过加权相互作用网络分析（WINA）和多尺度嵌入式基因共表达网络 分析（MEGENA）。然后，WINA和MEGENA衍生模块将与AD和的首要关键驱动因素相关联 与AD最相关的模块将成为实验验证的候选目标。我们还将确定 谷氨酸和tau蛋白介导的毒性的不同和交叉的途径，特别是在锥体神经元中， 海马的CA1和CA3区域。细菌人工染色体TRAP（BAC-TRAP）报告基因小鼠系， 结合谷氨酸稳态异常（EAAT 2-/-）和突变的人tau（P301S）模型， 在疾病进展的不同阶段产生海马CA1和CA3区域的翻译谱。 此外，我们还将评估EAAT 2，主要的谷氨酸转运蛋白，在tau蛋白积累，跨突触 tau扩散、免疫功能障碍和神经变性，以及其作为使用遗传（病毒）治疗靶点的潜力 载体）和化学（利鲁唑）方法。这一建议将提供新的见解的分子机制， 兴奋性神经元的易感性和弹性的抑制性神经元在AD中，确定潜在的新的治疗靶点， tau蛋白介导的神经退行性变，并提供了谷氨酸转运蛋白EAAT 2作为一种 炎症介质和tau病理学扩散。更好地了解潜在的分子 研究AD的发病机制对于开发新的和更有效的治疗靶点至关重要。这项建议 通过揭示疾病的新机制，有可能对AD领域产生重大影响， 确定特定的治疗靶点。

Project summary The hippocampus is important for learning and memory and is highly susceptible to aggregation of microtubule- associated protein tau (MAPT) and neurodegeneration. Hippocampal and neocortical atrophy in Alzheimer’s disease (AD) brains demonstrates degeneration predominantly in large glutamatergic pyramidal neurons in association cortices while inhibitory interneurons and primary cortices are resistant to MAPT accumulation and degeneration. However, the molecular mechanisms that cause damage and death of susceptible neurons are not understood. Developing a better understanding of the molecular mechanisms causing vulnerability of excitatory neurons to damage and identifying pathways that regulate tau-mediated neurodegeneration will be essential to unraveling the pathogenesis and progression of AD and identifying potential therapeutic targets. The primary goal of this proposal is to identify pathways that make excitatory neurons susceptible to tau accumulation and neurodegeneration, and identify potential therapeutic targets for AD. One important limitation is the cellular heterogeneity of the mammalian brain. To overcome the cellular heterogeneity, this proposal will innovatively use single cell RNA sequencing in fresh AD human brain tissue and viral translating ribosome affinity purification (vTRAP) in a mouse model of tauopathy to generate transcriptional profiles of excitatory and inhibitory neurons from vulnerable and resilient regions of the brain in the context of aging and neurodegeneration. Global gene co-expression networks for excitatory and inhibitory neurons will be constructed through Weighted Interaction Network Analysis (WINA) and Multiscale Embedded Gene co-Expression Network Analysis (MEGENA). WINA and MEGENA derived modules will then be associated with AD and the top key drivers of the modules most associated with AD will become the candidate targets for experimental validation. We will also identify distinct and intersecting pathways from glutamate and tau mediated toxicities specifically in the pyramidal neurons of CA1 and CA3 regions of the hippocampus. Bacterial artificial chromosome TRAP (BAC-TRAP) reporter mouse lines in conjunction with models of glutamate dyshomeostasis (EAAT2-/-) and mutant human tau (P301S) will be used to generate translational profiles of CA1 and CA3 regions of the hippocampus at various stages of disease progression. Further, we will also evaluate the role of EAAT2, the major glutamate transporter, in tau accumulation, trans synaptic tau spread, immune dysfunction and neurodegeneration, and its potential as a therapeutic target using genetic (viral vector) and chemical (riluzole) approaches. This proposal will provide novel insights into the molecular mechanisms of excitatory neuronal susceptibility and resilience of inhibitory neurons in AD, identify potential new therapeutic targets for tau-mediated neurodegeneration and provide a mechanistic understanding of glutamate transporter EAAT2 as a mediator of inflammation and spread of tau pathology. A better understanding of the underlying molecular mechanisms of AD is crucial for the development of novel and more effective therapeutic targets. This proposal has the potential to make a significant impact to the field of AD by uncovering novel mechanisms of disease and identification of specific therapeutic targets.