Biomarker Expression and Regulatory Haplotypes in Alzheimer's Disease

描述（由申请人提供）：阿尔茨海默病（AD）死后脑（PMB）的特征性发现是神经元变性以及大量淀粉样蛋白沉积（A？42)（由APP基因编码的淀粉样前体蛋白的切割产物）和tau（由MAPT基因编码）。脑脊液（CSF）A？42和tau水平可以预测AD，但在区分AD与其他神经退行性疾病方面具有有限的可靠性。载脂蛋白（APOE）？4等位基因和年龄是目前唯一与晚发性AD密切相关的因素。我们对AD遗传方面的理解存在很大差距，可能包括影响晚发型AD发病年龄和表型表达的其他遗传因素。与复杂疾病（如AD）相关的个体遗传发现（非同义SNP）不太可能完全解释遗传变异对疾病发病机制的实质性影响。多水平病因因素可能是复杂疾病的基础，可能包括影响转录和转录后调节的基因内和周围的多个位点，强调需要综合评估大的遗传区域和与蛋白质生物标志物水平的相关性作为预测疾病风险的手段。该建议集中在总体假设，即多个遗传位点周围和大基因区域内的行为，以调节基因表达的AD特异性的方式。在本研究的指导阶段（K99），首要目标是找到APOE、APP和MAPT基因周围和内部与CSF和PMB表达水平相关的多个基因座或SNP（单倍型）组合。候选遗传和蛋白质生物标志物将扩展到APOE、APP和MAPT基因之外，以包括可能与神经退行性疾病生物学相关的其他基因。第二个目的是通过利用基因组DNA，含有一个特定的推定的调节单倍型，作为报告基因和小基因测定中的基因调节的活性位点，证明推定的调节单倍型在功能上影响表达。在独立阶段（R 00），最终的目标是测试调节单倍型在不同AD表型之间以及AD和其他神经退行性疾病之间辨别的可靠性。总的来说，这些提出的实验是独特的，因为它们超越了核心启动子基因座和生物标志物表达水平之间的简单相关性，通过使用遗传，统计和功能技术的组合来评估多个基因座内的推定的远端调控元件对AD相关基因表达的影响，以找到预测AD的单倍型。该K99/R 00申请的研究和职业发展部分将为申请人提供必要的培训，使其成为一名成功的独立研究者，他们可以整合这些技术，以提高我们对神经退行性疾病风险的理解。 公共卫生相关性：表征AD相关表达水平的单倍型调控（生物标志物的遗传预测因子）可能有助于找到早期干预的新靶点，并转化为更准确的方法来预测并从而在其进展的早期诊断AD。

DESCRIPTION (provided by applicant): The characteristic findings in Alzheimer's disease (AD) post-mortem brain (PMB) are degeneration of neurons together with extensive amounts of amyloid deposits (A?42) (a cleavage product of the amyloid precursor protein encoded by the APP gene) and tau (encoded by the MAPT gene). Cerebrospinal fluid (CSF) A?42 and tau levels can predict AD but have a limited reliability in discriminating AD from other neurodegenerative diseases. The apolipoprotein (APOE) ?4 allele and age are currently the only factors strongly associated with late onset AD. The large gaps in our understanding of the genetic aspects of AD may include additional genetic factors that impact age of onset and phenotypic expression of late onset AD. Individual genetic findings (non- synonomous SNPs) associated with complex diseases, such as AD, are unlikely to fully explain the substantial impact of genetic variation on disease pathogenesis. Multilevel etiologic factors are likely to underlie complex diseases and may include multiple loci within and surrounding a gene that influence regulation of transcription and post-transcription, emphasizing the need for integrative evaluation of large genetic regions and correlations with protein biomarker levels as a means for predicting disease risk. This proposal focuses on the overall hypothesis that multiple genetic loci surrounding and within large gene regions act to regulate gene expression in an AD specific manner. During the mentored phase (K99) of this investigation the first aim is to find multiple loci or combinations of SNPs (haplotypes) surrounding and within the APOE, APP and MAPT genes that correlate with expression levels in CSF and PMB. Candidate genetic and protein biomarkers will expand beyond APOE, APP and MAPT genes to include other genes likely to be biologically relevant to neurodegenerative disease. The second aim is to demonstrate that putative regulatory haplotypes functionally impact expression by utilizing genomic DNA, containing a particular putative regulatory haplotype, as the active site of gene regulation in reporter and minigene assays. During the independent phase (R00), the final aim is to test regulatory haplotypes for their reliability in discerning between different AD phenotypes and between AD and other neurodegenerative diseases. Collectively, these proposed experiments are unique because they go beyond the simple correlation between core promoter loci and biomarker expression levels by using a combination of genetic, statistical and functional techniques to evaluate the influence of multiple loci within putative distant regulatory elements on AD relevant gene expression to find haplotypes that predict AD. The research and career development components of this K99/R00 application will provide the necessary training for the applicant to become a successful independent investigator who can integrate these techniques to improve our understanding of neurodegenerative disease risk. PUBLIC HEALTH RELEVANCE: Characterization of haplotype regulation of AD relevant expression levels (genetic predictors of biomarkers) may help find new targets for early intervention as well as translate into more accurate ways to predict and thus diagnose AD early in its progression.