ZINC AND ALZHEIMERS DISEASE PATHOPHYSIOLOGY

锌与阿尔茨海默病病理生理学

• 批准号: 6144902
• 负责人: ASHLEY I BUSH
• 金额: $ 5万
• 依托单位: MASSACHUSETTS GENERAL HOSPITAL
• 依托单位国家: 美国
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-09-01 至 2001-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6144902
• 关键词: Alzheimer's disease; Primates; amyloid proteins; apolipoprotein E; aspartate; blood brain barrier; brain metabolism; cerebrospinal fluid; chromatography; copper; deferoxamine; glutathione; laboratory rat; membrane permeability; metal metabolism; neuropharmacology; nicotine; nuclear magnetic resonance spectroscopy; positron emission tomography; protein metabolism; retinoid binding proteins; synthetic peptide; thyroid hormone binding protein; ultracentrifugation; zinc

Alzheimer's disease is characterized by amyloidotic deposits of 39-43 residue AB peptides, as well as multiple biochemical abnormalities in the brain. Synthetic A-beta-1-40 is soluble at high concentrations, and its native species has recently been described as a CSF component, but there is no evidence to indicate that its level is increased in AD. Since forms of familial Alzheimer's disease with characteristic amyloid pathology are caused by pathogenic mutations close to and within the A-beta domain of its parent molecule (the beta-amyloid protein precursor, APP), identification and characterization of physiological factors which cause A-beta to accumulate into amyloid would appear to provide important clues to the pathogenesis of the disease. Among the biochemical abnormalities of AD is a pervasive abnormality of cerebral zinc metabolism causing intraneuronal zinc deficiency and accumulation in the interstitial fluid. We have recently shown that A-beta specifically and saturably binds zinc, and has a similar high amity for copper. We found that concentrations of zinc above 300 nM rapidly destabilize synthetic A-beta-l-40 to solutions, and induce tinctorial amyloid formation. The rat species of A-beta, however, is immune from these effects, and binds zinc less avidly, consistent with the scarcity with which these animals form cerebral A- beta amyloid. In this proposal we propose to characterize the interaction of zinc with A-beta at the ultrastructural and conformational levels to determine the extent to which the consequences of low and high affinity zinc interaction are of relevance to amyloid or preamyloid formation. Hence, we will proceed to test whether the variant forms of A-beta (eg, A-beta 1-42 and A-beta with aspartate stereoisomer substitutions) could be disproportionately enriched in amyloid deposits because they are more vulnerable to zinc-induced aggregation than the major soluble form, A- beta 1-40. If this is shown to be true, then we will assay the ratios A- beta 1-42 to A-beta 1-40 in the CSF and brain regions in AD. The rapid aggregate filtration assay employed in these studies will be used to screen neurochemical agents (such as apolipoprotein E and antioxidants) for their anti-amyloidotic properties. To complement the in vitro findings that will be assembled from the proposed studies, we intend to recruit the necessary animal and chemical data required to develop an isotopic marker that may be suitable for positron emission tomography studies of human cerebral zinc metabolism. The goal of this proposal is to develop a thorough understanding of the structural consequences of the interaction of AB and its variants with zinc, and factors that modulate it, as well as a technical basis to proceed with in vivo studies of human cerebral zinc metabolism. Collectively, these data will provide a sound platform for exploring the potentially critical role of zinc in the neuropathogenesis of Alzheimer's disease.

阿尔茨海默病的特征是淀粉样沉积物39-43 残基AB肽，以及多种生化异常， 个脑袋合成的A-β-1-40在高浓度下是可溶的， 本地物种最近被描述为CSF成分，但 没有证据表明AD患者血清中的β-内酰胺酶水平升高。由于形式 家族性阿尔茨海默病的特征性淀粉样病理是 由接近和在A-β结构域内的致病性突变引起， 其母体分子（β-淀粉样蛋白前体，APP）， 鉴定和表征导致 β淀粉样蛋白积累成淀粉样蛋白似乎提供了重要的线索 疾病的发病机制 在生化异常中 AD是一种广泛的大脑锌代谢异常， 神经元内锌缺乏和间质液中的锌积累。 我们最近已经证明，A-β特异性和饱和结合锌， 并且对铜具有类似的高阿米蒂亲和性。我们发现， 高于300 nM的锌迅速使合成的A-β-l-40对溶液不稳定， 并诱导着色淀粉样蛋白形成。A-β的鼠种， 然而，对这些作用免疫，并且较不强烈地结合锌， 这与这些动物缺乏大脑A- β淀粉样蛋白在这个建议中，我们建议描述相互作用 锌与A-β在超微结构和构象水平， 确定低亲和力和高亲和力的影响程度 锌相互作用与淀粉样蛋白或类淀粉形成有关。 因此，我们将继续测试A-β的变体形式（例如， A-β 1-42和具有天冬氨酸立体异构体取代的A-β）可以 不成比例地富含淀粉样蛋白沉积物，因为它们更多 易受锌诱导的聚集比主要的可溶性形式，A- 贝塔1-40如果这被证明是真的，那么我们将分析A- β 1-42到A-β 1-40在AD的CSF和脑区域中。快速 这些研究中采用的聚集体过滤试验将用于 筛选神经化学试剂（如载脂蛋白E和抗氧化剂） 抗淀粉样变性的特性为了补充体外 根据拟议研究的结果，我们打算 收集必要的动物和化学数据，以制定 可适用于正电子发射断层摄影同位素标记物 人类大脑锌代谢的研究。这项提案的目的是 发展一个透彻的理解的结构性后果， AB及其变体与锌的相互作用，以及调节 它也是进行人体内研究的技术基础， 大脑锌代谢总的来说，这些数据将提供一个声音， 探索锌在生物体内潜在关键作用的平台 阿尔茨海默病的神经发病机制。