Identifying targets that lower APP as a therapeutic strategy for Alzheimer's disease

确定降低 APP 的靶标作为阿尔茨海默病的治疗策略

• 批准号: 10326784
• 负责人: Jennifer Leigh Johnson
• 金额: $ 6.86万
• 依托单位: BAYLOR COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-09-01 至 2022-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10326784
• 关键词: Abeta clearance; Adult; Alleles; Alzheimer' s Disease; Alzheimer' s disease model; Amyloid beta-42; Amyloid beta-Protein; Amyloid beta-Protein Precursor; Apolipoprotein E; Area; Automobile Driving; Back; Behavioral; Binding; Biochemical; Biology; Brain; Cell Line; Cell membrane; Cell model; Cells; Cholesterol Homeostasis; Clinical Trials; Data; Dependovirus; Development; Disease; Disease model; Down Syndrome; Drosophila genus; Drug Targeting; Enzyme-Linked Immunosorbent Assay; Family; Generations; Genes; Genetic study; Genome; Goals; Human; Human Amyloid Precursor Protein; Human Genetics; Huntington Disease; In Vitro; Individual; Induced pluripotent stem cell derived neurons; Injections; Knock-in; Label; Length; Link; Lipids; Measures; Mediating; Membrane; Modeling; Molecular Profiling; Mus; Nerve Degeneration; Neurodegenerative Disorders; Neurofibrillary Tangles; Neuronal Dysfunction; Neurons; Parkinson Disease; Pathogenicity; Pathologic; Pathway interactions; Patients; Peptides; Phase; Presenile Alzheimer Dementia; Proteins; Role; Source; Structure; Testing; Therapeutic; Therapeutic Effect; Toxic effect; Transgenic Organisms; Type 1 Spinocerebellar Ataxia; Vesicle; Western Blotting; Work; abeta accumulation; amyloid pathology; amyloid precursor protein processing; base; drug development; extracellular; fatty acid metabolism; fly; genetic risk factor; human embryonic stem cell; hyperphosphorylated tau; immunocytochemistry; in vivo; induced pluripotent stem cell; lipid metabolism; lipidomics; long chain fatty acid; mouse model; neuropathology; novel; overexpression; partial trisomy 21; polyglutamine; prevent; protein transport; small hairpin RNA; tau Proteins; tau phosphorylation; tau-1; therapeutic target; translational study

Project Summary AD, the most common neurodegenerative disease, is characterized pathologically by extracellular aggregation of Aβ [a cleavage product of amyloid precursor protein (APP)] and intraneuronal neurofibrillary tangles consisting of hyperphosphorylated tau. As such, AD belongs to the larger family of neurodegenerative proteopathies, which includes diseases such as Parkinson's (PD) and polyglutamine diseases such as Huntington's (HD) and spinocerebellar ataxia type 1 (SCA1). One of the many challenges facing drug development for AD is the lack of new targets capable of modifying the disease course. Ab is the main target for drugs currently in the pipeline, but it has not yielded any tangible benefits in clinical trials. The goal of this work is to elucidate the possible pathogenic role of a lipid pathway which regulates the levels of APP and may contribute to the development of AD. The idea that the brain is sensitive to the steady-state levels of APP is based on two major lines of evidence. First, studies of other neurodegenerative proteopathies such as PD and SCA1 have established that elevated levels of the disease-driving protein are pathogenic. Second, human genetic studies show that individuals carrying an extra copy of APP (e.g., those with Trisomy 21 or APP locus duplication) develop early-onset AD, but rare cases of partial trisomy 21(PT21), in which APP is not included in the trisomic segment, show no AD neuropathology. Because lowering the levels of a disease-driving protein have shown benefits in mouse models of SCA1, it is worth testing whether lowering abnormally elevated APP levels could prevent Aβ generation and mitigate disease. To identify novel regulators of APP, the Zoghbi lab performed parallel high-throughput shRNA screens in human cells and flies. Combined data from both screens identified a number of genes that, when inhibited, lowered full- length APP levels in a transgenic cell line expressing a fluorescently-labeled APP and mitigated toxicity in flies overexpressing human APP. These candidates were then further tested for their ability to regulate endogenous APP levels in human cells and surprisingly, I identified two genes, ACSL3 and SLC27A1, which function in the same pathway to regulate fatty acid metabolism. To determine if there were additional genes that fell into this pathway, I went back to the original primary cell-based screen data and uncovered a dozen additional genes involved in lipid metabolism which are absent in the fly genome and were therefore not previously validated. Three of these, ACOT8, ACADL, and ACAD10 have now been successfully validated in human cells. The overall objective of this proposal is to test these five candidates in a human cellular model of AD (Aim 1) and in mouse models of AD (Aim 2) to determine if full-length APP levels can be lowered, APP processing altered, amyloid pathology mitigated, and a potential mechanistic link between lipid metabolism and APP uncovered. The discovery of APP regulators will open new areas to understand APP biology, will provide potential therapeutic targets for cases of AD in which APP is increased, and will afford a rich source for genes that might increase vulnerability to AD.

项目概要 AD 是最常见的神经退行性疾病，其病理特征是细胞外聚集 Aβ [淀粉样前体蛋白 (APP) 的裂解产物] 和神经元内神经原纤维缠结组成 过度磷酸化的 tau 蛋白。因此，AD 属于神经退行性蛋白质病大家族， 包括帕金森病 (PD) 等疾病和亨廷顿舞蹈症 (HD) 等多聚谷氨酰胺疾病 脊髓小脑共济失调 1 型 (SCA1)。 AD 药物开发面临的众多挑战之一是缺乏 能够改变疾病进程的新目标。 Ab 是目前正在研发的药物的主要靶点，但是 它在临床试验中尚未产生任何切实的好处。这项工作的目标是阐明可能的 脂质途径的致病作用调节 APP 水平，并可能有助于疾病的发展 广告。大脑对 APP 的稳态水平敏感的观点基于两个主要证据。 首先，对其他神经退行性蛋白病（例如 PD 和 SCA1）的研究已证实，升高的水平 的疾病驱动蛋白具有致病性。其次，人类遗传学研究表明，携带某种基因的个体 额外的 APP 拷贝（例如，具有 21 三体或 APP 位点重复的患者）会发展为早发性 AD，但罕见病例 部分 21 三体性 (PT21)，其中 APP 不包含在三体片段中，未显示 AD 神经病理学特征。 由于降低疾病驱动蛋白的水平已在 SCA1 小鼠模型中显示出益处，因此值得 测试降低异常升高的 APP 水平是否可以防止 Aβ 生成并减轻疾病。到 为了确定 APP 的新型调节因子，Zoghbi 实验室在人体中进行了平行高通量 shRNA 筛选 细胞和苍蝇。两个筛选的综合数据确定了一些基因，当它们受到抑制时，会降低完全 表达荧光标记 APP 的转基因细胞系中长度 APP 水平并减轻果蝇毒性 过度表达人类APP。然后进一步测试这些候选者调节内源性的能力 令人惊讶的是，我发现了两个基因，ACSL3 和 SLC27A1，它们在 调节脂肪酸代谢的相同途径。确定是否有其他基因属于此范围 途径，我回到了最初的基于细胞的筛选数据，发现了十几个额外的基因 参与果蝇基因组中不存在的脂质代谢，因此之前未经验证。 其中三个，ACOT8、ACADL 和 ACAD10 现已在人体细胞中成功得到验证。整体 该提案的目的是在 AD 人类细胞模型（目标 1）和小鼠中测试这五种候选药物 AD 模型（目标 2）以确定是否可以降低全长 APP 水平、改变 APP 加工、淀粉样蛋白 病理学得到缓解，并且脂质代谢和 APP 之间潜在的机制联系被发现。这 APP 调节剂的发现将为了解 APP 生物学开辟新领域，并将提供潜在的治疗 APP 增加的 AD 病例的目标，并且将为可能增加的基因提供丰富的来源 AD 的脆弱性。