Protein-Protein Interactions in the Biology of Beta-APP

Beta-APP 生物学中的蛋白质-蛋白质相互作用

• 批准号: 7920117
• 负责人: DENNIS J SELKOE
• 金额: $ 33.83万
• 依托单位: BRIGHAM AND WOMEN'S HOSPITAL
• 依托单位国家: 美国
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-01-01 至 2013-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7920117
• 关键词: Abeta clearance; Abeta synthesis; Address; Adherent Culture; Age; Alzheimer' s Disease; Amyloid; Amyloid beta-Protein; Animal Model; Attention; Biochemical Genetics; Biological; Biology; Blood - brain barrier anatomy; Blood Circulation; Brain; Brain region; Cell Surface Receptors; Cell membrane; Cellular biology; Cerebrum; Complex; Conflict (Psychology); Cytopathology; Data; Defect; Disease; Endocytosis; Engineering; Epithelial; Future; Gene Transfer Techniques; Genetic; Grant; Herpesvirus Type 3; Human; In Vitro; Inherited; Insulin; Insulinase; Knock-out; Knowledge; Laboratories; Late Onset Alzheimer Disease; Left; Life; Literature; Mediating; Membrane Protein Traffic; Memory; Metalloproteases; Minority; Molecular; Mutagenesis; Mutation; Neprilysin; Peptide Hydrolases; Peptides; Peripheral; Primates; Production; Proteins; Proteolysis; RNA Interference; Research Personnel; Role; Scientist; Structure-Activity Relationship; Therapeutic; Thinking; Time; Work; age related; association cortex; base; brain cell; design; extracellular; fascinate; in vitro Model; in vivo; in vivo Model; insertion/deletion mutation; islet amyloid polypeptide; knock-down; mild neurocognitive impairment; mouse model; novel therapeutic intervention; presenilin; presenilin-1; prevent; protein protein interaction; protein transport; receptor; research study; secretase

DESCRIPTION (provided by applicant): Studies from many laboratories now generally support the amyloid (or Abeta) hypothesis of Alzheimer's disease (AD), and therapeutic trails based on this concept have begun. Nevertheless, we are left with many unresolved and fascinating biological questions about how a small hydrophobic peptide slowly accumulates in the brain with age and can apparently initiate cytopathology. Perhaps foremost among these questions is exactly why cerebral Abeta levels are elevated in humans who develop AD. Increased Abeta production appears to explain only a small minority of cases, principally those inheriting mutations in APP or the presenilins. This realization suggests that many, perhaps most, cases of AD are caused by faulty clearance of a peptide that is produced at normal levels throughout life. Our proposed work here is based on 3 related hypotheses: 1) defects in proteases which degrade Abeta may underlie some or many cases of familial and sporadic late-onset AD; 2) non-proteolytic clearance mechanisms (e.g., receptor-mediated efflux through the blood brain barrier) could explain the rise in cerebral Abeta in other cases; and 3) whether or not these two mechanisms are actually causative, subtly activating such proteases or else stimulating protein transport mechanisms could lower cerebral Abeta levels therapeutically. To extend our productive work under this grant on both the basic and applied aspects of this understudied subject, we propose 3 aims: Aim 1: To determine whether central or peripheral expression of engineered versions of two well-characterized Abeta degrading proteases - neprilysin and insulin degrading enzyme (IDE) -can safely and effectively decrease cerebral Abeta burden in mouse models of AD. Aim 2: In view of the recent unequivocal demonstration that IDE exists normally on the plasma membrane (namely, as the receptor for varicella-zoster virus), to further ellucidate the unusual cell biology and membrane trafficking of IDE that enables it to be involved in the degradation of both extracellular/intraluminal substrates (e.g., Abeta, insulin, amylin) and cytoplasmic substrates (e.g., AICD). Aim 3: To pursue a recently initiated project that addresses an even less well-studied aspect of Abeta clearance than proteolysis, namely, to rigorously identify and validate the cell- surface receptors capable of mediating the efflux of soluble Abeta across the BBB, using both in vitro and in vivo models. Understanding how both proteolysis and non-proteolytic clearance regulate Abeta levels in the brain has major implications for both the genesis and treatment of this complex disorder. At the same time, the proposed experiments have fundamental implications for peptide turnover in the mammalian brain and for the cell biology of metalloproteases. Many scientists now support the idea that the gradual buildup of a small protein, amyloid beta-protein (Abeta), in brain regions serving memory and thinking causes Alzheimer's disease. This grant will examine exactly why this buildup occurs over time, focusing on two potential problems: 1) faulty cutting up of the Abeta protein in the brain; or 2) faulty transport of the Abeta protein from the brain into the circulation. We will also explore new ways to increase the cutting up or the transport of Abeta as future therapeutic approaches for preventing Alzheimer's disease.

描述（由申请人提供）：许多实验室的研究现在普遍支持阿尔茨海默病（AD）的淀粉样蛋白（或Abeta）假说，并且基于该概念的治疗试验已经开始。然而，我们仍然有许多未解决的、令人着迷的生物学问题，即小的疏水性肽如何随着年龄的增长在大脑中缓慢积累，并明显引发细胞病理学。也许这些问题中最重要的就是为什么患有 AD 的人脑中 Abeta 水平会升高。 Abeta 产生的增加似乎只能解释一小部分病例，主要是那些遗传了 APP 或早老素突变的病例。这一认识表明，许多（也许是大多数）AD 病例是由一生中以正常水平产生的肽清除错误引起的。我们在这里提出的工作基于 3 个相关假设：1）降解 Abeta 的蛋白酶缺陷可能是一些或许多家族性和散发性迟发性 AD 病例的基础； 2) 非蛋白水解清除机制（例如，受体介导的通过血脑屏障的流出）可以解释其他情况下脑 Abeta 的升高； 3) 无论这两种机制是否确实是致病因素，巧妙地激活此类蛋白酶或刺激蛋白质转运机制都可以在治疗上降低大脑 Abeta 水平。为了扩展我们在这一资助下这一待研究课题的基础和应用方面的富有成效的工作，我们提出了 3 个目标： 目标 1：确定两种充分表征的 Abeta 降解蛋白酶（脑啡肽酶和胰岛素）的工程版本是中枢还是外周表达降解酶 (IDE) - 可以安全有效地降低 AD 小鼠模型的大脑 Abeta 负荷。 目标2：鉴于最近明确证明IDE正常存在于质膜上（即作为水痘带状疱疹病毒的受体），进一步阐明IDE的不寻常细胞生物学和膜运输使其能够参与细胞外/腔内底物（例如，Abeta、胰岛素、胰淀素）和细胞质底物（例如，AICD）的降解。 目标 3：开展一个最近启动的项目，解决 Abeta 清除中比蛋白水解研究更少的方面，即严格鉴定和验证能够介导可溶性 Abeta 跨 BBB 流出的细胞表面受体，同时使用体外和体内模型。了解蛋白水解和非蛋白水解清除如何调节大脑中的 Abeta 水平对于这种复杂疾病的发生和治疗具有重大意义。同时，所提出的实验对哺乳动物大脑中的肽周转和金属蛋白酶的细胞生物学具有根本意义。许多科学家现在都支持这样的观点：一种小蛋白质——淀粉样β蛋白（Abeta）在负责记忆和思维的大脑区域中逐渐积累会导致阿尔茨海默病。这笔资助将准确研究为什么这种积累会随着时间的推移而发生，重点关注两个潜在问题：1）大脑中 Abeta 蛋白的错误切割；或 2) Abeta 蛋白从大脑到循环系统的错误运输。我们还将探索增加 Abeta 切割或运输的新方法，作为预防阿尔茨海默病的未来治疗方法。