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

项目总结 海马体对学习和记忆很重要，非常容易受到微管聚集的影响。 相关蛋白tau(MAPT)与神经退行性变阿尔茨海默病患者的海马区和新皮质萎缩 (AD)大脑主要表现为联合皮质中大的谷氨酸能锥体神经元的变性。 而抑制性中间神经元和初级皮质对MAPT的积聚和变性具有抵抗力。然而， 导致易感神经元损伤和死亡的分子机制尚不清楚。发展更好的 兴奋性神经元损伤易损性的分子机制及其识别 调节tau介导的神经退行性变的通路将是解开发病机制和 AD的进展和寻找潜在的治疗靶点。这项提案的主要目标是确定路径 使兴奋性神经元易于tau积聚和神经变性，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。要克服蜂窝 异质性，这项建议将创新性地使用单细胞RNA测序在新鲜的AD人脑组织和病毒中 翻译核糖体亲和纯化(VTRAP)在牛磺酸病小鼠模型中产生转录图谱 大脑脆弱和恢复区的兴奋性和抑制性神经元在衰老和 神经退行性变。将构建兴奋性神经元和抑制性神经元的全球基因共表达网络 通过加权交互网络分析(WINA)和多尺度嵌入式基因共表达网络 分析(MEGENA)。然后，WINA和MEGENA派生模块将与AD和 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介导的毒性在大鼠锥体神经元中的不同和交叉通路 海马区的CA1和CA3区。细菌人工染色体陷阱(BAC-TRAP)报告小鼠品系 结合谷氨酸代谢紊乱模型(EAAT2-/-)和突变型人tau(P301S)将用于 在疾病发展的不同阶段生成海马体CA1和CA3区域的翻译配置文件。 此外，我们还将评估主要的谷氨酸转运体EAAT2在tau积累、跨突触 Tau的传播、免疫功能障碍和神经变性，及其作为基因(病毒)治疗靶点的潜力 (媒介)和化学(利鲁唑)方法。这一提议将为研究人类免疫缺陷的分子机制提供新的见解。 AD中兴奋性神经元的敏感性和抑制性神经元的弹性，寻找潜在的新的治疗靶点 并对谷氨酸转运体EAAT2作为一种 Tau病理炎症和扩散的中介物。更好地理解潜在的分子 阿尔茨海默病的机制对于开发新的、更有效的治疗靶点至关重要。这项建议 有可能通过揭示疾病和疾病的新机制对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.