Novel misfolded proteins in ADRD: proteomics, genetics, and clinical-pathological correlations

阿尔茨海默病和相关痴呆（ADRD）的异质性病理学仍然是 不完全理解。目前还没有一种理想的动物模型来研究这些疾病。四个已知的异常 错误折叠的蛋白质通常通过对ADRD患者的脑进行神经病理学检查来检测：Aβ，Tau， TDP-43和/或α-突触核蛋白。我们的初步数据表明，有更多的致病蛋白， 待鉴定的物种这些蛋白质的特征可能与以下疾病的发展有关： ADRD的诊断和治疗策略。本研究项目的目标是确定 ADRD中以前未表征、错误折叠和异常加工的蛋白质;解决基因变异 通过新的错误折叠蛋白调节痴呆的严重性和异质性;以及， 进行临床-病理相关性，重点关注这些新蛋白，以鉴定新的疾病相关性 病理生物标志物。我们将利用肯塔基州大学广告中心（UK-ADC）的资源 biobank和肯塔基州大学蛋白质组学核心设施，以执行以下特定目标： 具体目标1。人杏仁核（速冻）洗涤剂不溶性蛋白质提取物的分析 在尸体解剖时），以研究在ADRD中是否可检测到尚未表征的错误折叠蛋白。 多肽从洗涤剂不溶性，尿素可溶性蛋白质级分的杏仁核将被审问 使用质谱法。我们有来自40名UK-ADC受试者的手头杏仁核， 临床和病理特征谱。免疫组织化学和生物化学研究将 以确定用于额外研究的最佳候选蛋白质（目的2和3）。 具体目标2。构建一个强大的和协调的数据库与外显子测序定位 ADRD中与新型错误折叠蛋白相关的遗传区域。我们将测试 痴呆和编码候选错误折叠蛋白质的基因中罕见的外显子（“错义”）遗传变异 (Aim 1）。丰富的神经病理学内表型和纵向临床数据增强的遗传学数据将 使我们能够深入了解导致痴呆症的新机制。大规模数据集（NACC、ADGC、ADSP）将 汇总和协调以测试基于临床和神经病理学的遗传驱动因素 内表型集中在新的候选基因。候选靶基因已经被确定。 具体目标3。建立新型错误折叠的临床病理相关性 ADRD中的蛋白质病。我们将测试潜在的新型蛋白质病（来自 目的1）认知障碍，考虑已知的标志物Aβ，tau，α-Synuclein和TDP-43，以及 脑血管病我们有370个来自UK-ADC的样本可供分析（两性）， 这应该是统计学上的力量来检验我们的假设，即新的疾病的存在和严重程度， 错误折叠的蛋白质病理与认知损伤有关。

The heterogeneous pathologies of Alzheimer's disease and related dementias (ADRD) are still incompletely understood. There is no perfect animal model to study these diseases. Four known aberrantly misfolded proteins are commonly detected via neuropathologic examination of brains with ADRD: Aβ, Tau, TDP-43, and/or α-Synuclein. Our preliminary data indicate that there are more pathogenic protein species awaiting identification. Characterization of these proteins may be relevant to the development of both diagnostic and therapeutic strategies for ADRD. The goals of this research project are to identify previously uncharacterized, misfolded, and aberrantly processed proteins in ADRD; to resolve gene variants that modulate the severity and heterogeneity of dementia through the novel misfolded proteins; and, to perform clinical-pathological correlation, focusing on these novel proteins, to identify new disease-associated pathologic biomarkers. We will leverage the resources of the University of Kentucky AD Center (UK-ADC) biobank and the University of Kentucky Proteomics Core Facility, to execute the following Specific Aims: Specific Aim 1. Analyse detergent-insoluble protein extracts from human amygdala (snap-frozen at autopsy) to investigate whether as yet uncharacterized misfolded proteins are detectable in ADRD. Polypeptides from the detergent-insoluble, urea-soluble protein fractions of amygdala will be interrogated using mass spectrometry. We have on-hand amygdalae from 40 UK-ADC subjects which incorporate a spectrum of clinical and pathologic features. Immunohistochemistry and biochemical studies will be performed to determine the best candidate proteins for additional studies (Aims 2 and 3). Specific Aim 2. Construct a robust and harmonized database with exonic sequencing to localize genetic regions associated with novel misfolded proteins in ADRD. We will test the association between dementia and rare, exonic (`mis-sense') genetic variants in genes that encode candidate misfolded proteins (Aim 1). Genetics data augmented with rich neuropathologic endophenotypes and longitudinal clinical data will enable insights into novel mechanisms that drive dementia. Large-scale datasets (NACC, ADGC, ADSP) will be aggregated and harmonized to test the genetic drivers of clinical and neuropathology-based endophenotypes focusing on novel candidate genes. Candidate target genes have already been identified. Specific Aim 3. Establish the clinical-pathologic correlation for the novel misfolded proteinopathies in ADRD. We will test the association between the potential novel proteinopathies (from Aim 1) with cognitive impairment, factoring in known markers Aβ, tau, α-Synuclein, and TDP-43, as well as cerebrovascular pathologies. We have 370 samples available for analyses (both sexes) from the UK-ADC, which should be statistically powered to test our hypothesis that the presence and severity of novel misfolding protein pathologies are associated with cognitive impairment.