Neuronal Network Regulation in A-Beta and Tau Conformation and Spreading

项目摘要/摘要 β多肽在大脑中的积聚似乎引发了阿尔茨海默病(AD)，包括tau 聚集，然后在疾病进展中发挥主要作用。在AD的人类和动物模型中， 突触活动水平最高的大脑区域显示出最多的Aβ斑块，这表明 β的产生与突触传递密切相关。我们实验室的研究表明，直接 突触活动的调节动态调节清醒动物的脑Aβ和tau水平， 突触活动增加迅速增加脑间质液Aβ和tau水平，反之亦然 被抑制的活动。这些发现有力地表明，突触活动之间存在密切的时间关系 大脑中Aβ和tau的水平也是如此。脑细胞外间隙在阿尔茨海默病中起着特别重要的作用 生物学。β斑块是一种细胞外结构，其中大部分β建立在现有斑块上 来自大脑的声音。过度磷酸化的tau缠结是细胞内的结构，并且很长 被认为是独立于ISF的；然而，最近的研究表明tau可以从 一个神经元进入ISF，然后内化成一个幼稚的神经元，破坏该神经元的细胞内tau 导致聚集。了解调节脑内β和tau动力学的机制应该 为了解疾病的发病机制提供了有价值的见解。 我们假设Aβ和tau的病理形式在突触中的大脑区域之间扩散- 依赖的态度。我们认为，神经元在网络中的功能不仅是调节Aβ的量 和tau的释放，还包括构象(单体、低聚物等)。被释放的Aβ和Tau的。目标1 将决定突触频率与Aβ/tau水平和物种之间的关系。目标2将 确定谷氨酸和GABA能神经元如何独立地影响间质干细胞中的A、β和tau。和目标 3将确定目标脑区的局部突触活动如何影响tau的传播。虽然有几个 研究表明，启动脑区内的突触活动驱动Aβ和tau的分泌。 靶区，树突状靶区内的局部突触活动如何影响tau的摄取、传播和 播种情况未知。 我们开发了一种新的微免疫电极(MIE)技术，用于检测Aβ和tau 在活着的小鼠的大脑中具有非常高的时间分辨率(在体内每60秒测量一次β 几个小时)。MIE对Aβ40、Aβ42、Tau或它们的聚集体具有高度的选择性，使我们能够 确定突触活动如何在体内调节这些多肽和构象的快速动态。 在这项建议中，我们将利用MIES来测量完整神经元内Aβ和tau水平的快速变化 网络和特定的小区类型。研究将包括年轻的APP/PS1小鼠和年轻的P301S小鼠 在Aβ或Tau病理之前，以及老年病理荷瘤小鼠如何确定病理事件 改变活性与ISF蛋白代谢的关系。我们还将使用APP/PS1和 P301S小鼠一起饲养，以确定突触Aβ如何影响突触tau的生成，反之亦然。

Project Summary/Abstract Accumulation of Aβ peptide in the brain appears to initiate Alzheimer’s disease (AD), including tau aggregation which then plays a major role in disease progression. In humans and animal models of AD, brain regions with the highest levels of synaptic activity show the greatest amount of Aβ plaques, suggesting Aβ production is closely related to synaptic transmission. Studies from our lab have demonstrated that direct modulation of synaptic activity dynamically regulates brain Aβ and tau levels in awake animals, with increased synaptic activity rapidly increasing brain interstitial fluid (ISF) Aβ and tau levels and vice versa for suppressed activity. These findings strongly suggest a close temporal relationship between synaptic activity and Aβ and tau levels in the brain ISF. The brain extracellular space plays a particularly important role in AD biology. Aβ plaques are extracellular structures with the majority of Aβ that builds onto an existing plaque coming from the brain ISF. Hyperphosphorylated tau tangles are intracellular structures and were long thought to be independent of the ISF; however, recent studies demonstrate that tau can be secreted from one neuron into the ISF, then internalized into a naïve neuron to corrupt intracellular tau in that neuron and cause aggregation. Understanding mechanisms that regulate Aβ and tau kinetics within the brain ISF should provide valuable insight into disease pathogenesis. We hypothesize that pathological forms of Aβ and tau are spread between brain regions in a synaptic- dependent manner. We propose that neurons function within a network to regulate not only the amount of Aβ and tau released, but also the conformation (monomer, oligomers, etc.) of Aβ and tau that is released. Aim 1 will determine the relationship between synaptic frequency and Aβ/tau levels and species. Aim 2 will determine how glutamatergic and GABAergic neurons independently impact Aβ and tau in the ISF. And Aim 3 will determine how local synaptic activity within target brain region affects tau propagation. While several studies suggest that synaptic activity within the initiating brain region drives Aβ and tau secretion in the target region, how local synaptic activity within the dendritic target region affects tau uptake, propagation and seeding is unknown. We have developed a novel micro-immunoelectrode electrode (MIE) technology that detects Aβ and tau with very high temporal resolution in the brains of living mice (measures Aβ in vivo every 60 seconds over several hours). MIEs are highly selective for either Aβ40, Aβ42, tau, or their aggregates, enabling us to determine how synaptic activity regulates the rapid dynamics of these peptides and conformations in vivo. In this proposal we will utilize MIEs to measure rapid changes in Aβ and tau levels within intact neuronal networks and from specific cell types. Studies will include young APP/PS1 mice and young P301S mice prior to Aβ or tau pathology, as well as aged pathology-bearing mice to determine how pathological events change the relationship between activity and ISF protein metabolism. We will also use the APP/PS1 and P301S mice bred together to determine how synaptic Aβ impacts synaptic tau generation, and vice versa.