Disruption of neuronal signaling in Alzheimer’s disease and rescue by manipulating the innate immune receptor PirB

项目摘要 阿尔茨海默病（AD）随着我们的人口老龄化而变得越来越普遍，其特征在于： 严重的记忆丧失和认知障碍神经元突触的修剪有助于 是AD的病理学特征，并且是认知下降的最佳相关性。寡聚淀粉样蛋白β和 神经炎症机制可导致AD中的突触修剪。虽然神经元和免疫细胞 已经显示出相互作用以驱动修剪，这种相互作用的神经元信号传导下游并不好 明白这项提议的一个主要目标是确定驱动突触的神经元信号机制， 在两个年龄和两个年龄的不同条件下修剪常染色体显性AD小鼠模型 聚集的淀粉样蛋白β和免疫激活。 突触修剪在整个发育过程中自然发生，有一种假设认为， 修剪机制在AD中失调。沙茨实验室有了惊人的发现， 免疫受体PirB在神经元中表达，并在发育过程中的突触修剪中起作用。在 此外，成年小鼠中的PirB敲除，无论是整体还是单独在兴奋性神经元中， 重新开启关键期的突触可塑性。PirB及其人类同源物LilrB 2， 两者都显示出以高亲和力结合淀粉样蛋白β，而种系全局PirB敲除显示出 在AD的APP/PS1小鼠模型中防止记忆丧失。虽然全球生殖系敲除是 在治疗背景下，确定PirB阻断在正常情况下的作用也是重要的。 在疾病进展的不同阶段饲养成年小鼠。此外，虽然Shatz实验室发现了一种 信号通路连接PirB突触修剪，通过cofilin的去磷酸化，没有其他信号 已经在APP/PS1小鼠中检查了PirB下游的信号通路。 在这里，我建议测试的假设，神经元基因表达失调，在AD模型小鼠 并且可以用PirB KO恢复，防止突触丢失。拟议的实验应确定 AD模型小鼠中PirB下游神经元和突触中的新信号通路。我亦建议 在正常饲养的成年APP/PS1小鼠中阻断PirB以确定PirB/LilrB 2的治疗潜力 AD中的封锁。我专注于疾病进展的两个阶段：1）早期，在斑块形成之前， 已经报道了突触和记忆缺陷，和2）晚期，在斑块形成和免疫增强后 activation.这项建议的中心目标是使用转录组学，生物化学，电生理学， 行为技术来阐明AD中PirB/LilrB 2下游的信号通路，并证明 PirB阻断“治疗”APP/PS1模型小鼠记忆丧失的治疗潜力。这一长期目标 研究有助于我们理解导致突触修剪的信号机制， 阿尔茨海默病，作为寻找潜在疗法和治疗靶点的第一步。

Project Summary Alzheimer’s disease (AD) is becoming more prevalent as our population ages and is characterized by devastating memory loss and cognitive impairment. The pruning of neuronal synapses contributes to the pathology of AD and is the best correlate of cognitive decline. Both oligomeric amyloid beta and neuroinflammatory mechanisms can lead to synapse pruning in AD. While neurons and immune cells have been shown to interact to drive pruning, the neuronal signaling downstream of this interaction is not well understood. A major goal of this proposal is to determine neuronal signaling mechanisms driving synapse pruning in mouse models of autosomal dominant AD at two ages and under varying conditions of both aggregated amyloid beta and immune activation. Synapse pruning occurs naturally throughout development, and one hypothesis is that developmental pruning mechanisms are dysregulated in AD. The Shatz lab made the surprising discovery that the innate immune receptor, PirB, is expressed in neurons and has roles in synapse pruning over development. In addition, PirB knockout in adult mice, either globally or in excitatory neurons alone, facilitates the rapid growth of new synapses and re-opens critical period-like synaptic plasticity. PirB and its human homologue, LilrB2, have both been shown to bind amyloid beta at high affinities, and germline global PirB knockout was shown to protect against memory loss in the APP/PS1 mouse model of AD. While global germline knockout was protective, in a therapeutic context, it is also important to determine the effect of PirB blockade in normally reared adult mice at various stages of disease progression. In addition, while the Shatz lab identified a signaling pathway linking PirB to synapse pruning, via the dephosphorylation of cofilin, no other signaling pathways have been examined downstream of PirB in APP/PS1 mice. Here, I propose to test the hypothesis that neuronal gene expression is dysregulated in AD model mice and can be restored with PirB KO, protecting against synapse loss. The experiments proposed should identify new signaling pathways in neurons and at synapses downstream of PirB in AD model mice. I also propose to block PirB in normally reared adult APP/PS1 mice to determine the therapeutic potential of PirB/LilrB2 blockade in AD. I focus on two stages of disease progression: 1) early, before plaque formation but when synaptic and memory deficits have been reported, and 2) late, after plaque formation and heightened immune activation. The central goal of this proposal is to use transcriptomic, biochemical, electrophysiological, and behavioral techniques to elucidate signaling pathways downstream of PirB/LilrB2 in AD and demonstrate the therapeutic potential of PirB blockade to ‘treat’ memory loss in APP/PS1 model mice. The long-term aim of this research is to contribute to our understanding of the signaling mechanisms leading to synaptic pruning in Alzheimer’s disease, as a first step toward finding potential therapies and therapeutic targets.