Peptide Biomarkers for Parkinson Disease

 描述(由申请人提供)：客观、可靠和可重复的生物标志物显然是帮助准确诊断帕金森病(PD)，特别是在早期阶段，以及促进鉴别诊断和疾病监测所必需的。该提案旨在应对当前生物标记物研究的几个主要挑战，特别是：1)与基于抗体的蛋白质分析相关的显著差异，2)基于血液的标记物的低敏感性和特异性，以及3)早期帕金森病的检测。为了解决基于抗体的分析的问题，我们的策略是开发基于靶向质谱学的技术，例如选择性反应监测，以识别来自先前蛋白质组学分析中显示前景的蛋白质或已知对帕金森病发病关键的蛋白质的独特的多肽标记，例如α-synuclein、parkin和LRRK2。为了便于发现和验证基于血液的生物标志物，在SRM分析之前，将分离特定人群的中枢神经系统来源的血浆外体，即最近发现的用于在不同细胞或器官系统之间运输生物分子的载货微囊。这些独特的多肽标记物将在几个大型、成熟的队列中进行测试，例如华盛顿大学和宾夕法尼亚大学附属的Udall中心、DATATOP(帕金森病的Deprenyl和生育酚抗氧化疗法)和PPMI(帕金森进展标记物倡议)，收集横断面和纵向样本，以及广泛的临床特征。最后，为了改进早期诊断，我们将利用两个由帕金森病高风险受试者组成的队列(即，有LRRK2突变或无嗅觉/嗅觉减退的无症状受试者)，目的是发现能够识别早期或运动性帕金森病患者的生物标志物。为该项目设计的研究如果成功，有可能导致一组生物标志物(S)的研究，这些生物标志物比目前所能实现的更强大，变化更小，并且产生在常规临床环境中容易获得的体液。帕金森病早期诊断和进展的标志物对于了解如何阻止或减缓帕金森病进展至关重要。

 DESCRIPTION (provided by applicant): Objective, reliable, and reproducible biomarkers are clearly needed to assist with accurate diagnosis of Parkinson disease (PD), especially at early stages, as well as for facilitating differential diagnosis and disease monitoring. The proposal is designed to meet several major challenges of current biomarker research, specifically: 1) significant variations associated with antibody-based protein assays, 2) low sensitivity and specificity of blood based markers, and 3) detection of PD at early stages. To address the problems of antibody-based assays, our strategy is development of targeted mass spectrometry-based techniques, such as selected reaction monitoring (SRM), to identify unique peptide markers derived from proteins either showing promise in previous proteomics profiling, or known to be critical to PD pathogenesis, e.g., α-synuclein, parkin and LRRK2, in human cerebrospinal fluid (CSF). To facilitate discovery and validation of blood based biomarkers, a specific population of central nervous system derived plasma exosomes, the cargo-carrying microvesicles recognized recently to transport biomolecules among different cells or organ systems, will be isolated before SRM analysis. The unique peptide markers will be tested in several large, well-established cohorts, e.g., Udall Centers affiliated with the University of Washington and University of Pennsylvania, DATATOP (Deprenyl and tocopherol antioxidative therapy of parkinsonism) and PPMI (Parkinson Progression Marker Initiative), with cross-sectional and longitudinal samples collected, along with extensive clinical characterization. Finally, to improve early diagnosis, we will make use of two cohorts consisting of subjects at elevated risk for PD (i.e., asymptomatic subjects with LRRK2 mutations or anosmia/hyposmia), with the goal of discovering biomarkers capable of identifying subjects with early or premotor PD. The studies designed for this project, if successful, have the potential to result in a panel(s of biomarkers that are robust, with less variation than can currently be achieved, and in a body fluid that is readily accessible in a regular clinical setting. Markers for early diagnosis and progression of PD are critical in understanding how to arrest or slow PD progression.