A Molecular Signaling Pathway Underlying Differential Predisposition of ApoE4 Genotype to Alzheimer's Disease

ApoE4 基因型对阿尔茨海默病的差异易感性背后的分子信号通路

• 批准号: 10213580
• 负责人: Yu-Wen Alvin Huang
• 金额: $ 23.21万
• 依托单位: BROWN UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-07-15 至 2022-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10213580
• 关键词: Abeta synthesis; Address; Affect; Age; Aging; Alleles; Alzheimer' s Disease; Alzheimer' s disease risk; Amyloid beta-Protein; Amyloid beta-Protein Precursor; Animal Behavior; Animals; Apolipoprotein E; Behavioral; Binding Sites; Biological Assay; Brain; CRISPR interference; Chronic; Data; Development; Dominant-Negative Mutation; Elements; Event; Future; Gene Proteins; Genetic; Genetic Transcription; Genotype; Healthcare; Hippocampus (Brain); Homo sapiens; Human; Impaired cognition; Inherited; Injections; Knock-out; Knowledge; Learning; Lentivirus; Leucine Zippers; Light; MAP Kinase Gene; MAPK Signaling Pathway Pathway; Measures; Mediating; Memory; Mission; Molecular; Mus; Neuroglia; Neurons; Output; Pathogenesis; Pathway interactions; Peptide Hydrolases; Pharmacology; Phosphotransferases; Predisposition; Prevention; Primates; Promoter Regions; Protein Isoforms; Public Health; Reporter; Reporting; Research; Role; Series; Signal Pathway; Signal Transduction; Site; System; Technology; Testing; Therapeutic; Training; Transcription Factor AP-1; Transcriptional Regulation; Translations; United States; United States National Institutes of Health; Virus; abeta deposition; apolipoprotein E-3; apolipoprotein E-4; base; behavior test; career; disability; experimental study; genetic epidemiology; genetic risk factor; genetic variant; human embryonic stem cell; in vivo; induced pluripotent stem cell; innovation; knock-down; mutant; novel; novel therapeutics; overexpression; promoter; training opportunity; transcription factor; β-amyloid burden

PROJECT SUMMARY/ABSTRACT Inheritance of Apolipoprotein E (ApoE) gene variant APOE-ϵ4 is the strongest genetic risk factor for Alzheimer’s disease (AD), a rapidly growing burden of health care for the aging United States. There is a fundamental gap in understanding how expression of APOE-ϵ4, which encodes ApoE isoform ApoE4, influences neuronal function and contributes to AD pathogenesis. This gap, until filled, represents our insufficiency in understanding AD and our inability to provide treatment and prevention to AD and risk carriers. A central event in AD pathogenesis is deposition of amyloid-β (Aβ) peptide, generated from a series of protease cleavages of amyloid precursor protein (APP). Using pure human neurons derived from human embryonic stem cells or iPSCs, the applicant has recently identified a signaling pathway by which ApoE4 stimulates APP transcription and consequently induces Aβ production in neurons, more effectively than the other two isoforms ApoE2 and ApoE3. This pathway hinges on double leucine-zipper kinase DLK and downstream MAPK signaling, and is activated by three ApoE isoforms differentially in the potency rank order of ApoE4>ApoE3>ApoE2, paralleling AD risk rank order. Given this striking ApoE isoform-specific effect, the overall objective of this application is to determine whether and how ApoE4-specific activation of DLK/MAPK signaling pathway may account for ApoE4’s deleterious AD-promoting effect. My central hypothesis is that ApoE4 may predispose to AD by stimulating DLK/MAPK and increasing neuronal Aβ production chronically, and that interference with ApoE-enhanced APP transcription via manipulations of DLK/MAPK pathway may delay AD pathogenesis. I plan to test my central hypothesis, thereby accomplishing the overall objective for this project by pursuing these following specific aims: 1) Determine whether DLK/MAPK pathway mediates differential APP/Aβ induction by ApoE isoforms, ApoE4>ApoE3>ApoE2, 2) Identify the transcription control elements of APP gene required for ApoE stimulation, and 3) Determine the functional output of DLK/MAPK pathway in vivo. A combination of genetic and pharmacological manipulations will be used to enhance or inhibit ApoE-activated DLK/MAPK pathway in cultured neurons and in animal brains. The molecular mechanism and behavioral significance of this pathway will be rigorously examined. The overall approach is innovative because it departs from the status quo by utilizing human neurons and focusing on the underappreciated mechanisms of APP transcription in light of AD pathogenesis. The proposed research is significant, because it is expected to define a new role of ApoE in the brain, and also to explore new therapeutic horizons by targeting DLK-MAPK pathway as an alternative strategy. Findings will advance greatly our knowledge of AD pathogenesis, and have strong potential for future translation into urgently needed treatment and prevention.

项目总结/摘要 载脂蛋白E（ApoE）基因变异体APOE-104的遗传是最强的遗传危险因素， 阿尔茨海默氏病（AD）是美国老龄化的医疗保健负担迅速增长。有一个 在理解编码ApoE同种型ApoE 4的APOE-β 4如何表达方面存在根本差距， 影响神经元功能并促进AD发病机制。这一差距，直到填补，代表我们的 我们对AD的认识不足，无法为AD和风险携带者提供治疗和预防。 AD发病机制中的中心事件是淀粉样蛋白-β（Aβ）肽的沉积，其由一系列 淀粉样前体蛋白（APP）的蛋白酶裂解。使用纯人类神经元， 在胚胎干细胞或iPSC中，申请人最近鉴定了ApoE 4通过其表达的信号传导途径。 刺激APP转录，从而诱导神经元中Aβ的产生， 另外两种亚型ApoE 2和ApoE 3。该途径依赖于双亮氨酸拉链激酶DLK和 下游MAPK信号传导，并被三种ApoE亚型激活，其效力等级顺序为 ApoE 4> ApoE 3> ApoE 2，与AD危险性排序平行。鉴于这种惊人的ApoE亚型特异性效应， 本申请的总体目标是确定DLK/MAPK的ApoE 4特异性活化是否以及如何 信号通路可能解释了ApoE 4的有害AD促进作用。我的核心假设是 ApoE 4可能通过长期刺激DLK/MAPK和增加神经元Aβ的产生而易患AD， 通过调控DLK/MAPK通路干扰ApoE增强的APP转录可能 延缓AD发病。我计划测试我的中心假设，从而实现总体目标， 本项目通过追求以下具体目标：1）确定DLK/MAPK通路是否介导 通过ApoE同种型的差异APP/Aβ诱导，ApoE 4> ApoE 3> ApoE 2，2）鉴定转录控制 ApoE刺激所需的APP基因元件，和3）确定DLK/MAPK的功能输出 体内途径。基因和药理学操作的组合将用于增强或抑制 在培养的神经元和动物脑中ApoE激活DLK/MAPK通路。的分子机制和 这一途径的行为意义将被严格审查。总体方法具有创新性 因为它通过利用人类神经元并专注于未被重视的 根据AD发病机制研究APP的转录机制。这项研究意义重大，因为它 有望定义ApoE在大脑中的新作用，并通过靶向治疗探索新的治疗视野。 DLK-MAPK通路作为替代策略。研究结果将大大提高我们对AD的认识 发病机制，并有很强的潜力，未来转化为迫切需要的治疗和预防。