Novel nuclear and intracellular pathology in early AD

AD 早期的新核和细胞内病理学

• 批准号: 8702666
• 负责人: Paul D Gershon
• 金额: $ 24.45万
• 依托单位: UNIVERSITY OF CALIFORNIA-IRVINE
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-05-01 至 2016-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8702666
• 关键词: 3xTg-AD mouse; Alzheimer' s Disease; Amyloid; Amyloid Fibrils; Amyloid beta-Protein Precursor; Antibodies; Area; Asses; Biogenesis; Biological Assay; Brain; Cell Nucleus; Clinical Trials; Cognitive deficits; DNA; Detergents; Development; Digestion; Disease; Effectiveness; Endopeptidase K; Epitopes; Etiology; Event; Excision; Fluorescent Dyes; Generic Drugs; Genes; Goals; Human; Human Genetics; Immune Sera; Impaired cognition; Mass Spectrum Analysis; Mediator of activation protein; Modeling; Monoclonal Antibodies; Mus; Neurites; Neurons; Nuclear; Pathogenesis; Pathology; Pathway interactions; Patients; Peptide Hydrolases; Peptides; Post-Translational Protein Processing; Presenile Alzheimer Dementia; Production; Protein Fragment; Proteins; Proteolysis; Proteolytic Processing; Public Health; Reporting; Resistance; Resources; Risk Factors; Senile Plaques; Serum; Solubility; Source; Spatial Distribution; Staging; Staining method; Stains; Structure; Testing; Thinking; Time; Transgenic Mice; Trypsin; Western Blotting; aged; alpha synuclein; amyloid precursor protein processing; brain tissue; extracellular; gamma secretase; immunoreactivity; inhibitor/antagonist; islet amyloid polypeptide; mind control; neuron loss; novel; prevent; protein aggregate; protein misfolding; public health relevance; response; therapeutic development

DESCRIPTION (provided by applicant): This proposal seeks to transform our understanding of the causes and mechanisms of Alzheimer's disease. Alzheimer's disease is one of the most serious and economically important diseases for which there is no disease modifying therapy. The problem for therapeutic development in AD is that there is no commonly understood mechanism for AD pathogenesis. Human genetics implicates the APP and its proteolytic processing and the production of the amyloid A? peptide as a mediator of pathogenesis, but human clinical trials targeting the secretion of A? or the removal of plaques have demonstrated little or no effectiveness or have actually accelerated cognitive decline. Recent trials of gamma secretase inhibitors that prevent the secretion of A? reported that treated patients were cognitively worse than controls, suggesting that out understanding of the disease mechanisms is flawed or incomplete. The goal of this proposal is to identify and characterize the proteins and protein fragments that accumulate in and around the nuclei that are reactive to the fibril specific monoclonal antibody M78. We will test the hypothesis that APP and its amyloidogenic fragments misfold and aggregate into insoluble species prior to their proteolytic conversion to A? and accumulate intracellularly due to the intrinsic resistance of the aggregated A? domain to proteolysis. In preliminary studies we have discovered a novel amyloid fibril immunoreactivity in and around nuclei using a fibril specific monoclonal antibody, M78, which recognizes a discontinuous A? epitope in A? fibrils. Our studies suggest that M78 immunoreactivity colocalizes with both intracellular perinuclear APP and early extracellular plaque stages of AD prior to significant cognitive dysfunction and at intermediate times of pathogenesis in 3xTg-Ad mice. Some of the nuclear M78 immunoreactivity colocalizes with APP and A? as visualized with APP and A? specific antibodies suggesting that M78 immunoreactivity may represent misfolded, aggregated APP or APP fragments accumulating as "intracellular amyloid". In 3xTg-AD mice, M78 positive plaques accumulate at later times that are not stained with 6E10 or 4G8, suggesting that a unique type of plaque is also identified by this monoclonal antibody. We also observed that the same spatial distribution of M78 and APP immunoreactivity in neuritic plaques is colocalized with DNA visualized with the fluorescent dye DAPI located in the central core of the neuritic plaque surrounded by a halo of APP immunoreactivity in "dystrophic neurites". Together, our observations suggest a previously unidentified nuclear related intracellular pathway for amyloid pathogenesis and plaque biogenesis in AD. If this novel pathogenesis is a key event in AD, it will dramatically change our way of thinking about this disease, refocus the resources for therapeutic development and enable early clinical trials to alter the course of the disease.

描述（由申请人提供）：该提案旨在改变我们对阿尔茨海默氏病病因和机制的理解。阿尔茨海默病是最严重且经济上最重要的疾病之一，目前尚无疾病缓解疗法。 AD 治疗开发的问题在于 AD 发病机制尚无普遍了解的机制。人类遗传学涉及 APP 及其蛋白水解加工以及淀粉样蛋白 A 的产生？肽作为发病机制的介质，但人体临床试验针对的是A？或者去除斑块的效果很小或没有效果，或者实际上加速了认知能力的下降。最近的伽马分泌酶抑制剂试验可阻止 A? 的分泌。报道称，治疗患者的认知能力比对照组差，这表明我们对疾病机制的理解是有缺陷或不完整的。该提案的目标是识别和表征蛋白质和 聚集在细胞核内和细胞核周围的蛋白质片段，对原纤维特异性有反应 单克隆抗体M78。我们将测试以下假设：APP 及其淀粉样蛋白生成片段在蛋白水解转化为 A？之前错误折叠并聚集成不溶性物质。并由于聚集的 A? 的内在阻力而在细胞内积累。域到蛋白水解。在初步研究中，我们使用原纤维特异性单克隆抗体 M78 在细胞核内和细胞核周围发现了一种新型淀粉样原纤维免疫反应性，该抗体可识别不连续的 A？ A 中的表位？原纤维。我们的研究表明，在 3xTg-Ad 小鼠中，在显着认知功能障碍之前和发病中期，M78 免疫反应性与 AD 的细胞内核周 APP 和早期细胞外斑块阶段共定位。一些核 M78 免疫反应性与 APP 和 A？如 APP 和 A 所示？特异性抗体表明 M78 免疫反应性可能代表错误折叠、聚集的 APP 或 APP 片段累积为“细胞内淀粉样蛋白”。在 3xTg-AD 小鼠中，M78 阳性斑块在稍后时间积累，未用 6E10 或 4G8 染色，表明该单克隆抗体还识别了一种独特类型的斑块。我们还观察到，神经炎斑块中 M78 和 APP 免疫反应性的相同空间分布与使用荧光染料 DAPI 可视化的 DNA 共定位，该 DNA 位于神经炎斑块的中央核心，周围环绕着“营养不良的神经突”中的 APP 免疫反应性光环。总之，我们的观察结果表明，AD 中淀粉样蛋白发病机制和斑块生物发生中存在先前未识别的核相关细胞内途径。如果这种新的发病机制是 AD 的关键事件，它将极大地改变我们对这种疾病的思考方式，重新集中资源用于治疗开发，并使早期临床试验能够改变疾病的进程。