Understanding the Role of Blood-Based Parkinson's Disease Biomarkers in Neurodegeneration

项目摘要/摘要 帕金森病(PD)是世界上第二大最常见的神经退行性疾病，与 伴有细胞内α-突触核蛋白(α-SYN)包涵体和进行性神经元丢失。目前没有一种疾病 由于对疾病发病机制缺乏了解和缺乏明确的干预措施而修改帕金森病的治疗方法 目标。尽管全基因组关联研究(GWAS)有所增加，但在PD领域仍有未得到满足的需求 (1)用于理解PD进展的因果导联的产生和(2)这些导联的机械性随访 阐明它们在神经退行性变中的作用。为此，陈-普洛特金实验室进行了无偏见的蛋白质组学研究 在3个临床地点对450名患者和对照组的1,000种血浆蛋白进行筛选。这项研究的结果是140 发现队列中与帕金森病相关的候选血浆生物标志物。此外，低水平的血浆 预测了糖蛋白非转移蛋白B(GPNMB)--一个先前被认为与帕金森病相关的基因 随后认知能力下降的速度更快。因此，本提案旨在(1)确定哪些线索 通过这个无偏见的筛选产生的是与PD有因果关系的，并(2)了解如何改变 GPNMB水平有助于帕金森病患者的神经退变。目标1将检验这样的假设，即因果线索可以 使用孟德尔随机化(MR)进行识别，这是一种使用遗传变异作为工具的统计技术 来推断因果关系。磁共振将应用于先前通过执行蛋白质数量性状确定的线索 基因座(PQTL)研究，并结合现有的GWAS数据进行因果推断。目标2将检验这一假设 低水平的GPNMB通过增加神经元对α-SYN诱导的敏感性而导致神经变性 毒性。为了在更大的队列中验证现有的GPNMB QTL和生物标志物签名，GPNMB在 用双抗体夹心法对196例PD患者和98例正常对照的血浆和脑脊液进行定量。第二，检验 GPNMB水平对α-SYN介导的毒性作用，GPNMB将在小鼠原代皮质神经元和 人类IPSC来源的神经元。然后细胞将用α-SYN预形成的纤维(能够播种刘易斯)处理 体外体样病理)，并评估1)α-SYN播种和聚集的读数，2)自噬小体- 溶酶体功能，以及3)神经元健康。该项目不仅将为帕金森病的发病机制提供有用的见解， 还将允许申请者通过以下方式接受计算和细胞/分子生物学方法的培训 实验的执行、参加研讨会、课程和科学会议以及正式的指导 来自经验丰富的指导团队。此外，作为一个存储数千个患者样本和 宾夕法尼亚大学神经退行性疾病中心附属实验室陈普洛金实验室 宾夕法尼亚州特别适合支持申请者完成这一项目。

Project Summary/Abstract Parkinson’s disease (PD) is the 2nd most common neurodegenerative disorder in the world and is associated with intracellular α-synuclein (α-syn) inclusions and progressive neuronal loss. There are currently no disease modifying therapies for PD due to a poor understanding of disease pathogenesis and lack of clearly intervenable targets. Despite a rise in genome-wide association studies (GWAS), there is an unmet need in the PD field for (1) generation of causal leads for understanding PD progression and (2) mechanistic follow-up of these leads to elucidate their role in neurodegeneration. To this end, the Chen-Plotkin lab performed an unbiased proteomic screen of >1,000 plasma proteins in >450 patients and controls across 3 clinical sites. This study resulted in 140 candidate plasma biomarkers that associated with PD in the discovery cohort. Furthermore, low levels of plasma Glycoprotein non-metastatic protein B (GPNMB) – a locus previously associated with PD by GWAS – predicted faster rate of subsequent cognitive decline. Thus, this proposal aims to (1) identify which of the leads generated through this unbiased screen are causally linked to PD and to (2) understand how altered levels of GPNMB contribute to neurodegeneration in PD. Aim 1 will test the hypothesis that causal leads can be identified using mendelian randomization (MR), a statistical technique using genetic variants as instruments to deduce causality. MR will be applied to leads identified previously by performing a protein quantitative trait loci (pQTL) study and incorporating existing GWAS data for causal inference. Aim 2 will test the hypothesis that low levels of GPNMB contribute to neurodegeneration by increasing neuronal susceptibility to α-syn-induced toxicity. To validate existing GPNMB QTL and biomarker signatures in a larger cohort, GPNMB expression in plasma and CSF of 196 PD patients and 98 controls will be quantified by ELISA. Second, to test the effect of GPNMB levels on α-syn-mediated toxicity, GPNMB will be manipulated in mouse primary cortical neurons and human iPSC-derived neurons. Cells will then be treated with α-syn pre-formed fibrils (capable of seeding Lewy Body-like pathology in vitro) and assessed for readouts of 1) α-syn seeding and aggregation, 2) autophagosomal- lysosomal function, and 3) neuronal health. This project will not only provide useful insight into PD pathogenesis, but will also allow the applicant to train in both computational and cellular/molecular biology approaches through the performance of experiments, attendance at seminars, courses, and scientific meetings, and formal guidance from an experienced mentorship team. Furthermore, as a biobank housing thousands of patient samples and an affiliated lab of the Penn Center for Neurodegenerative Diseases, the Chen-Plotkin lab at the University of Pennsylvania is particularly well suited to support the applicant in completion of this project.