Structures and Toxicity of Amyloid Protein Assemblies in Alzheimer's

阿尔茨海默病中淀粉样蛋白组装体的结构和毒性

• 批准号: 8043940
• 负责人: YOSHITAKA ISHII
• 金额: $ 28.15万
• 依托单位: UNIVERSITY OF ILLINOIS AT CHICAGO
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-09-01 至 2015-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8043940
• 关键词: Accounting; Address; Alzheimer' s Disease; Amino Acid Sequence; Amino Acids; Amyloid; Amyloid Fibrils; Amyloid Proteins; Amyloid fibers; Attention; Binding; Binding Sites; Biochemical; Brain; Cell Death; Chemical Structure; Chemicals; Coupled; Development; Drug Design; Early Diagnosis; Electron Microscopy; Enzymes; Exhibits; Fluorescence Spectroscopy; Freezing; Functional disorder; Heterogeneity; Hydrogen Peroxide; Hydroxyl Radical; Ions; Kinetics; Label; Ligands; Location; Metals; Methods; Modeling; Modification; Molecular; Molecular Conformation; Molecular Structure; Morphology; Mus; Mutation; Nature; Neurons; Neurotoxins; Oxidation-Reduction; PC12 Cells; Peptides; Peroxides; Play; Preparation; Proteins; Reaction; Research; Role; Sampling; Senile Plaques; Signal Transduction; Site; Solutions; Structure; Testing; Time; Toxic effect; Transmission Electron Microscopy; Variant; X-Ray Crystallography; amyloid peptide; amyloid structure; design; insight; meetings; mutant; neurotoxic; neurotoxicity; novel; relating to nervous system; self assembly; solid state nuclear magnetic resonance; structural biology; tool

DESCRIPTION (provided by applicant): The long-term objective of this research is to identify the origin of neural cell deaths observed in Alzheimer's disease (AD) through investigating molecular details of three types of highly toxic protein assemblies of Alzheimer's ¿-amyloid (A¿), which are commonly observed in AD. The formation of senile plaques in a brain is a hall mark of Alzheimer's disease (AD); the primary component of the plaque is fibrillar assemblies comprised of A¿. Because A¿ exhibits toxicity through self-assembly into larger aggregated forms (i.e. monomeric A¿ is non-toxic), it has been long suspected that misfolding of A¿ resulting in the fibril formation and structural changes of A¿ via the self-assembly trigger the onset of the toxicity and the neural dysfunctions in AD. Indeed, the toxicity of the aggregated A¿ is greatly modulated by morphologies of the assembled A¿, subtle difference in the sequence, and the presence of particular ligands such as Cu(II). In this research, we will examine atomic-level structures of three distinctive forms of toxic amyloid aggregates for A¿ by solid-state NMR (SSNMR), which has been used as a primary tool in structural analysis for amyloid fibrils, including those for A¿. In Aim 1, we will examine a popular hypothesis that the toxicity of A¿ is associated with Cu(II) binding to A¿ aggregates. It is widely believed that Cu(II)-bound amyloid aggregates may catalyze reactions producing H2O2, which is toxic to neural cells. However, because of the intrinsic heterogeneity of the fibrils, traditional methods in structural biology such as X-ray crystallography and solution NMR are not effective for analysis of the metal-binding structures. With SSNMR, we will examine the location and the mode of Cu(II) binding to A¿ as well as any structural changes due to binding. In Aim 2, we target the structure of amyloid fibrils and diffusible subfibrillar aggregates for A¿(1-42), which have been poorly characterized, despite their pathogenic importance, because of the extreme difficulties in sample preparation. Molecular structures of these amyloid fibrils and intermediates for A¿(1-42) have attracted broad attention since the structures offer insights into designs of new therapies and early detection for AD. We will overcome the sample preparation problems by using a novel sensitivity enhancement method, which minimizes sample amount required for SSNMR. The studies will reveal the first site-specific structural details of highly neurotoxic amyloid fibril and intermediate for A¿(1-42) by SSNMR. In Aim 3, we characterize structure and kinetics in misfolding for E22G A¿(1-40), which is a unique pathogenic mutant that promotes formation of subfibrillar aggregates. Our study aims to reveal site-specific conformations for E22G A¿(1-40) fibrils and subfibrillar aggregates for the first time. The neural toxicity of the relevant amyloid aggregates will be examined on mouse PC12 cells. PUBLIC HEALTH RELEVANCE: This project provides detailed molecular structure for neurotoxic proteins, which are likely to play central roles in development of Alzheimer's disease. The research will provide insights into rational designs of drugs for Alzheimer's.

描述（由适用提供）：这项研究的长期目的是通过研究三种类型的高毒蛋白质组件的分子细节来确定阿尔茨海默氏病（AD）在阿尔茨海默氏症（Alzheimer's） - 淀粉样蛋白（A a）的分子细节中观察到的。大脑中老年斑块的形成是阿尔茨海默氏病（AD）的大厅。牙菌斑的主要成分是完成了a。的原纤维组件。由于A通过自我组装成较大的聚集形式（即单体a。是无毒的），因此长期以来一直怀疑对A的折叠折箱的错误折叠会导致A a。通过自组装触发AD的纤维形成和结构变化。实际上，聚集的a。的毒性受到组装a的形态，序列的细微差异以及特定配体（例如cu（ii）的存在）非常调节。在这项研究中，我们将研究固态NMR（SSNMR）的三种独特形式的有毒淀粉样蛋白聚集体的原子级结构，该结构已用作淀粉样纤维的结构分析的主要工具，包括A级。在AIM 1中，我们将研究一个流行的假设，即a的毒性与Cu（II）与A聚合物结合有关。人们普遍认为，Cu（II）结合的淀粉样蛋白聚集体可能会催化产生对神经细胞有毒的H2O2的反应。但是，由于原纤维的内在异质性，X射线晶体学和溶液NMR等结构生物学的传统方法对于分析金属结合结构无效。使用SSNMR，我们将检查Cu（II）与A的位置和模式以及由于结合而引起的任何结构变化。在AIM 2中，我们针对淀粉样蛋白原纤维的结构和可扩散的亚纤维骨料（1-42），由于样品制备中的极端困难，它们的病原意义很差。这些淀粉样蛋白原纤维和中间体的分子结构（1-42）引起了广泛的关注，因为这些结构提供了对新疗法设计和AD的早期检测的见解。我们将使用一种新型的灵敏度增强方法来克服样品制备问题，该方法可最大程度地减少SSNMR所需的样品量。这些研究将揭示SSNMR高度神经毒性淀粉样蛋白原纤维的第一个位点特异性结构细节和A中间的A（1-42）中间。在AIM 3中，我们表征了E22Ga¿（1-40）错误折叠中的结构和动力学，这是一种独特的致病突变体，可促进亚纤维聚集体的形成。我们的研究旨在首次揭示E22G A（1-40）纤维和亚纤维骨料的特定地点构象。相关淀粉样蛋白聚集体的神经毒性将在小鼠PC12细胞上检查。 公共卫生相关性：该项目为神经毒性蛋白提供了详细的分子结构，这些蛋白可能在阿尔茨海默氏病发展中起着核心作用。这项研究将为阿尔茨海默氏症药物的理性设计提供见解。