Identification of an Abeta fragment produced by BACE2

BACE2 产生的 Abeta 片段的鉴定

• 批准号: 8038128
• 负责人: DONALD C LO
• 金额: $ 7.85万
• 依托单位: DUKE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-01-01 至 2012-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8038128
• 关键词: Academia; Adult; Age; Alzheimer' s Disease; Alzheimer' s disease model; Alzheimer' s disease risk; Amyloid; Amyloid beta-Protein; Amyloid beta-Protein Precursor; Antibodies; Birth; Brain; C-terminal; Chromosomes, Human, Pair 21; Cleaved cell; Clinical; Data; Dementia; Deposition; Development; Diagnostic; Diffuse; Down Syndrome; Drug Delivery Systems; Elderly; Gene Expression; General Population; Genes; Genetic; Goals; Human Chromosomes; Incidence; Industry; Lead; Length; Literature; Measures; Mediating; Mental Retardation; Messenger RNA; Molecular Genetics; Nerve Degeneration; Neurites; Neurofibrillary Tangles; Neurologic; Neurons; Pathology; Patients; Peptides; Pharmaceutical Preparations; Population; Presenile Alzheimer Dementia; Process; Production; Protein Isoforms; Proteins; Reagent; Reporting; Research; Research Proposals; Senile Plaques; Slice; Testing; Trisomy; aged; amyloid peptide; base; beta-site APP cleaving enzyme 1; beta-site APP cleaving enzyme 2; combat; design; familial Alzheimer disease; inhibitor/antagonist; neuron loss; novel; novel therapeutics; prevent; secretase; tau Proteins; tool

DESCRIPTION (provided by applicant): Down syndrome (DS) results from triplication of human chromosome 21 (chr21) and is the most common genetic cause of mental retardation. It is hypothesized that DS is initiated by increased expression of genes located on the triplicated chr21, causing abnormal brain development in DS, but also resulting in further neurological complications, prominently Alzheimer's disease (AD)-like dementia, as DS patients grow into adulthood. By a number of neurological and neuropathological criteria, the DS population is at substantially elevated risk for AD-like neurodegeneration-and by at least 20-30 years earlier than the general population. In conducting a hypothesis-neutral screen of genes located on the DS trisomy for enhancement of amyloid precursor protein (APP)-induced neurodegeneration, we found that one of these genes, the - secretase enzyme BACE2, appears to enhance the rate/extent of neuronal degeneration in a brain slice-based model of AD. Based on previous reports in the literature and our preliminary studies, we hypothesize that BACE2 cleavage of APP generates a truncated version of ¿-amyloid (A¿) that may not be amyloidogenic but nevertheless drives significant neurodegenerative processes even in the absence of full-length A¿. In order to rigorously test this hypothesis, it will be necessary to directly identify and characterize this presumptive A¿ fragment generated by BACE2. However, currently available immunoreagents are not suitable for this purpose. Thus, the goal of this research proposal is to develop and test novel antibodies directed at the presumptive BACE2 A¿ fragment; to use these reagents to demonstrate that a truncated form of A¿ is produced by BACE2 cleavage of APP; and finally to isolate and directly sequence the BACE2-truncated A¿ fragment. The specific aims are thus to: Specific Aim 1: Develop an antibody to the C-terminal half of the canonical A¿ sequence. Specific Aim 2: Directly MS sequence the A¿ fragment produced by BACE2 cleavage. If successful, this research strategy will provide further evidence and the tools necessary for testing the hypothesis that BACE2 could be a favorable potential drug target for slowing/preventing the progression of AD-like neurodegeneration in DS. Moreover, given that BACE2 is also expressed in the brains of the general population, albeit at lower levels, such BACE2-targeted drugs may also be important to investigate in the context of sporadic and familial AD, as the highly-selective BACE1 inhibitor drugs being developed today could "unmask" neurodegenerative processes mediated by BACE2 that may be latent in the general population as well. PUBLIC HEALTH RELEVANCE: Down syndrome (DS) results from the triplication of human chromosome 21 (chr21) and, with an incidence of 1 in ~750 births, is the most common genetic cause of mental retardation. Tragically, as DS patients grow into adulthood, they suffer from further neurological complications, most notably Alzheimer's disease (AD)-like dementia - at present, there are no drugs available to patients that can slow or halt the progression of early-onset AD in DS. There is thus an urgent need to understand the underlying molecular genetic mechanisms that lead to AD in DS in order to support the rational design of new therapeutics to combat AD in DS. In this context, the present proposal seeks to develop key immunoreagents to enable testing the hypothesis that one of the DS trisomy genes, BACE2, may be an important drug target candidate for the treatment of AD in DS, and potentially for treating AD in the general population as well.

描述（由适用提供）：唐氏综合症（DS）由人类染色体21（CHR21）的一式三份而导致，是智力低下的最常见遗传原因。假设DS是由位于三率CHR21上的基因表达增加而引发的，导致DS中的脑发育异常，但也导致了进一步的神经系统并发症，随着DS患者的成长，Alzheimer氏病（AD）类似痴呆症。根据许多神经病理学和神经病理学标准，DS人群的AD样神经变性的风险显着升高，并且比一般人群早至少20至30年。在进行位于DS三体上的基因的假设 - 中性筛选时，用于增强淀粉样蛋白前体蛋白（APP）诱导的神经变性，我们发现这些基因之一，即 - 泌尿酶酶Bace2，似乎增强了AD基于大脑Slice基于AD的神经元退化的速率/程度。基于文献和初步研究的先前报告，我们假设APP的Bace2裂解会产生截断的„ - 淀粉样淀粉样蛋白（a。）可能不是淀粉样蛋白生成的，但即使在没有全长a a的情况下也可以推动大量的神经退行性过程。为了严格检验这一假设，有必要直接识别和表征由Bace2产生的假定A片段。但是，目前可用的免疫反应不适合此目的。这是该研究建议的目的是开发和测试针对假定Bace2 a片段的新型抗体。使用这些试剂证明AP的BACE2裂解产生了A。的截断形式；最后，要分离并直接对Bace2截断的A片段进行排序。因此，具体目的是：特定目标1：开发针对规范A序列的C末端一半的抗体。特定目标2：直接MS序列BACE2清洁产生的A片段。如果成功的话，该研究策略将提供进一步的证据和测试BACE2可能是减慢/防止DS中AD样神经变性发展的潜在药物目标的假设所必需的工具。此外，鉴于BACE2在普通人群的大脑中也表达，尽管在较低的水平上，因此在散发性和家庭AD的背景下，这种面向2个靶向的药物也可能很重要，因为今天开发的高度选择性的Bace1抑制剂可能会“不掩盖” NeuroDegenerative Process2，因此由bace2介导，以致是bace2介导的。 公共卫生相关性：唐氏综合症（DS）是由人类染色体21（CHR21）的一式三次降低的，并且有1分在〜750个出生的事件中，是最常见的智力抑制遗传学原因。可悲的是，随着DS患者成年的成年，他们患有进一步的神经系统并发症，最著名的是阿尔茨海默氏病（AD）类似痴呆症 - 目前，尚无患者可用的药物可以减慢或停止DS中早期AD的进展。因此，迫切需要了解导致DS中AD的基本分子遗传机制，以支持新疗法的合理设计以对抗DS中的AD。在这种情况下，本提案旨在开发关键的免疫反应，以便能够检验以下假设：DS三体基因BACE2可能是DS中AD治疗的重要药物靶向候选者，并且有可能在普通人群中治疗AD。