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

阿尔茨海默病神经元信号传导的破坏以及通过操纵先天免疫受体 PirB 进行挽救

• 批准号: 10231468
• 负责人: Johanna Elizabeth Tomorsky
• 金额: $ 6.64万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-05-01 至 2024-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10231468
• 关键词: APP-PS1; Acute; Adult; Affinity; Age; Alleles; Alzheimer' s Disease; Alzheimer' s disease model; Alzheimer' s disease pathology; Amyloid beta-Protein; Astrocytes; Automobile Driving; Behavioral; Behavioral Paradigm; Binding; Biochemical; Cells; Cessation of life; Crystallization; Development; Disease Progression; Dominant-Negative Mutation; Electrophysiology (science); Electroporation; Functional disorder; Gene Expression; Gene Proteins; Genes; Goals; Histocompatibility; Homologous Gene; Human; Immune; Immune signaling; Immunoglobulins; Immunologic Receptors; Impaired cognition; Inflammation; Injury; Knock-out; Lead; Length; Ligands; Link; LoxP-flanked allele; Mass Spectrum Analysis; Measures; Memory; Memory Loss; Memory impairment; Microglia; Mus; Neurofibrillary Tangles; Neurons; Pathologic; Pathway interactions; Pattern; Phosphorylation; Population; Prosencephalon; Protein Dephosphorylation; Proteins; Recombinant Proteins; Reporting; Research; RiboTag; Role; Signal Pathway; Signal Transduction; Structure; Synapses; Synaptic plasticity; Synaptosomes; Tamoxifen; Techniques; Testing; Therapeutic; Time; Transgenes; abeta accumulation; aged; autosomal dominant Alzheimer' s disease; calmodulin-dependent protein kinase II; cell type; cofilin; conditional knockout; critical period; druggable target; excitatory neuron; experimental study; follow-up; hyperphosphorylated tau; immune activation; in utero; knock-down; macrophage; mouse model; nanomolar; neuroinflammation; neuron loss; neurotransmission; new growth; novel; oAβ; prevent; rapid growth; receptor; response; small hairpin RNA; synaptic function; synaptic pruning; therapeutic target; transcriptome sequencing; transcriptomics

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.

项目概要 随着人口老龄化，阿尔茨海默病 (AD) 变得越来越普遍，其特点是 毁灭性的记忆丧失和认知障碍。神经元突触的修剪有助于 AD 的病理学与认知能力下降的最佳相关性。寡聚淀粉样蛋白 β 和 神经炎症机制可能导致 AD 中的突触修剪。虽然神经元和免疫细胞具有 已被证明相互作用以驱动修剪，但这种相互作用下游的神经元信号传导并不好 明白了。该提案的一个主要目标是确定驱动突触的神经元信号传导机制 在两个年龄和不同条件下对常染色体显性 AD 小鼠模型进行修剪 聚集的β淀粉样蛋白和免疫激活。 突触修剪在整个发育过程中自然发生，一种假设是发育过程 AD 中的修剪机制失调。沙茨实验室做出了令人惊讶的发现，即先天性 免疫受体 PirB 在神经元中表达，在发育过程中的突触修剪中发挥作用。在 此外，成年小鼠中的 PirB 敲除，无论是整体敲除还是仅敲除兴奋性神经元，都促进了快速生长 新的突触并重新开启关键时期的突触可塑性。 PirB 及其人类同源物 LilrB2， 两者均已被证明能够以高亲和力结合β淀粉样蛋白，并且种系全局 PirB 敲除被证明可以 防止 AD APP/PS1 小鼠模型的记忆丧失。虽然全球种系敲除 保护性，在治疗背景下，确定 PirB 阻断在正常情况下的效果也很重要 饲养处于疾病进展不同阶段的成年小鼠。此外，虽然沙茨实验室发现了 连接 PirB 和突触修剪的信号通路，通过丝切蛋白的去磷酸化，没有其他信号传导 已在 APP/PS1 小鼠中检查了 PirB 下游的通路。 在这里，我建议检验 AD 模型小鼠神经元基因表达失调的假设 并且可以用 PirB KO 恢复，防止突触丢失。提议的实验应确定 AD 模型小鼠神经元和 PirB 下游突触中的新信号通路。我也提议 在正常饲养的成年 APP/PS1 小鼠中阻断 PirB，以确定 PirB/LilrB2 的治疗潜力 公元封锁。我关注疾病进展的两个阶段：1）早期，在斑块形成之前，但当 据报道，突触和记忆缺陷，以及 2) 晚期，在斑块形成和免疫增强之后 激活。该提案的中心目标是利用转录组学、生物化学、电生理学和 行为技术阐明 AD 中 PirB/LilrB2 下游信号通路并证明 PirB 阻断“治疗”APP/PS1 模型小鼠记忆丧失的治疗潜力。本次活动的长远目标 研究旨在帮助我们理解导致突触修剪的信号机制 阿尔茨海默病，这是寻找潜在疗法和治疗靶点的第一步。