Transgenic C. elegans as Amyloid Disease Model

描述（由申请人提供）：尽管有令人信服的证据表明β -淀粉样肽（Abeta）在阿尔茨海默病的病理中起核心作用，但Abeta的毒性机制及其特定靶点仍未得到解决。本项目是我们以秀丽隐杆线虫为模型，深入研究（人类）β毒性基础的研究的延续。我们之前已经证明，转基因蠕虫表达人类Abeta 1-42，复制阿尔茨海默病病理的某些方面。通过分子和遗传方法的结合，我们现在已经确定了一组在这些转基因蠕虫模型中调节β毒性的保守基因。此外，对表达单氨基酸变体的转基因蠕虫的分析已经导致鉴定出一种在体内基本上无毒的Abeta变体。本提案的目标是综合这些发现来确定：1)有毒Abeta物种的身份，2)影响有毒物种形成的细胞途径，以及3)Abeta的特定细胞靶点。本提案的具体目的是：1)通过构建和表征表达变异Abeta肽的转基因蠕虫，对Abeta毒性进行体内结构/功能分析。这些研究将直接测试“有毒的Abeta寡聚物”模型，2)确定进化保守的修饰基因改变Abeta毒性的分子机制，以及3)验证我们在哺乳动物细胞培养和原代神经元培养中发现的Abeta毒性和保护基因的机制。我们提出的研究对阿尔茨海默病的诊断和治疗有直接的相关性。确定Abeta的主要毒性形式可能对设计防止其形成或毒性活性的药物至关重要。表征影响Abeta毒性的基因可能对阿尔茨海默病和其他神经退行性疾病的风险评估和有效干预措施的发展都很重要。

DESCRIPTION (provided by applicant): Although there is compelling evidence that the beta-amyloid peptide (Abeta) is centrally involved in Alzheimer's disease pathology, the mechanisms of Abeta toxicity and its specific targets remain unresolved. This project is a continuation of our studies using the intensely studied nematode worm Caenorhabditis elegans as a model to investigate the basis of (human) Abeta toxicity. We have previously shown that transgenic worms engineered to express human Abeta 1-42, replicate some aspects of Alzheimer's disease pathology. By a combination of molecular and genetic approaches, we have now identified a set of conserved genes that modulate Abeta toxicity in these transgenic worm models. In addition, analysis of transgenic worms expressing single amino acid variants has led to the identification of an Abeta variant that is substantially non-toxic in vivo. The goal of this proposal is to synthesize these findings to establish: 1) the identity of the toxic Abeta species, 2) the cellular pathways that influence the formation of the toxic species, and 3) the specific cellular targets of Abeta. The Specific Aims of this proposal are to: 1) perform an in vivo structure/function analysis of Abeta toxicity by constructing and characterizing transgenic worms expressing variant Abeta peptides. These studies will directly test the "toxic Abeta oligomer" model, 2) determine the molecular mechanisms by which evolutionarily conserved modifier genes alter Abeta toxicity, and 3) validate the proposed mechanisms for both Abeta toxicity and the protective genes we have identified using mammalian cell culture and primary neuronal cultures. Our proposed studies have direct relevance for the diagnosis and treatment of Alzheimer's disease. The identity of the key toxic form(s) of Abeta may be critical for designing drugs that prevent its formation or toxic activity. Characterization of genes that affect the toxicity of Abeta may be important for both risk assessment and the development of effective interventions for Alzheimer's and other neurodegenerative diseases.