Salivary Extracellular Vesicles as Biomarkers for Alzheimer's Disease and Related Disorders

项目摘要：阿尔茨海默病 (AD) 和相关疾病 (ADRD)，包括额颞叶痴呆 (FTD)、帕金森病 (PD)、路易体痴呆 (DLB) 和肌萎缩侧索硬化症 (ALS)， 导致老龄化人口的显着发病率和死亡率。尽管经过几十年的研究，仍然没有 预防或延缓这些疾病进展的有效治疗。目前，有测试可用于 识别有患 AD 风险的个体，但这些测试需要脑脊液检测或正电子检测 发射断层扫描（PET）来测量淀粉样蛋白水平，这分别是侵入性的或成本高昂的， 限制了它们的用处。虽然使用淀粉样蛋白和 tau 生物标志物进行基于血液的诊断测试正在 开发用于诊断有症状个体的 AD 病理学，其对临床前疾病的预测价值是 仍然未知。此外，目前还没有针对 ADRD 的血液测试。自 AD 和 ADRD 发展过程可能会跨越数十年，因此需要识别在此期间的个体 潜在干预措施可能更有效的临床前阶段。为了解决我们无法诊断的问题 风险个人，我们在布朗大学和罗德岛组建了一个多学科研究小组 Island Hospital 的长期目标是发现可用于临床的易于获取的生物标志物 设置以在 AD 或 ADRD 痴呆症发作之前识别出罹患 AD 或 ADRD 痴呆症风险增加的个体 蛋白质病。我们课题组最近发表在细胞外可检测到AD相关mRNA转录本 从脑外伤患者唾液中分离出的囊泡（EV）。我们的初步数据显示，患者 患有轻度认知障碍 (MCI) 和轻度 AD 的人有 43 个 mRNA 转录本和 5 个 miRNA 发生改变 唾液 EV 中的代表性。此外，认知正常的人，PET 扫描结果呈阳性 β42 淀粉样蛋白的 mRNA 和 miRNA 谱与 MCI 和轻度 AD 患者相似。基于此 我们假设唾液 EV 的 mRNA、miRNA 和蛋白质组成将提供有效的数据 用于 AD 及相关患者早期诊断和疾病进展跟踪的生物标志物 神经退行性疾病。为了验证这一假设，我们将使用转录组学和蛋白质组学方法 定义了唾液 EV 中存在的一组 RNA 和蛋白质生物标志物，可预测个体的患病风险 具体目标 1 中的 AD。具体目标 2 将扩展这些研究以识别 RNA 和蛋白质生物标志物 存在于从 FTD、PD、DLB 和 ALS 患者中分离出的唾液 EV 中。在具体目标 3 中，我们将确定 通过以下方法研究临床前至 AD 临床进展过程中唾液 EV 成分变化的动态 3-5 年内淀粉样蛋白 β42 血液检测呈阳性的认知正常个体队列。数据 在这个项目中获得的成果将使我们能够识别唾液 EV 中存在的生物标志物，这些生物标志物可以用作简单的、 无创筛查机制，用于在临床前阶段检测有患 AD 风险的患者 治疗可能更有效。

Project Summary: Alzheimer's disease (AD) and Related Disorders (ADRD), including frontotemporal dementia (FTD), Parkinson's disease (PD), dementia with Lewy bodies (DLB), and amyotrophic lateral sclerosis (ALS), cause significant morbidity and mortality in aging populations. Despite decades of research, there are still no effective treatments to prevent or delay progression of these illnesses. Currently, there are tests available to identify individuals at risk of developing AD, but these tests require either a cerebral spinal fluid assay or positron emission tomography (PET) to measure amyloid levels, which are invasive or cost prohibitive, respectively, limiting their usefulness. While blood based diagnostic tests using amyloid and tau biomarkers are being developed to diagnose AD pathology in symptomatic individuals, their predictive value for preclinical disease is still unknown. Furthermore, there are currently no blood-based tests available for ADRDs. Since AD and ADRD develop over a prolonged period that can span decades, there is a need to identify individuals during this preclinical period when potential interventions may be more effective. To address our inability to diagnose at- risk individuals, we have put together a multidisciplinary team of investigators at Brown University and Rhode Island Hospital with the long-term goal to discover easily accessible biomarkers that can be used in a clinical setting to identify individuals at increased risk of developing AD or ADRD dementias prior to the onset of proteinopathies. Our group recently published that AD-related mRNA transcripts can be detected in extracellular vesicles (EVs) isolated from saliva in patients with traumatic brain injury. Our preliminary data show that patients with mild cognitive impairment (MCI) and mild AD have 43 mRNA transcripts and 5 miRNAs that show altered representation in salivary EVs. In addition, cognitively normal individuals with a PET scan that is positive for amyloid β42 have mRNA and miRNA profiles that are similar to the MCI and mild AD patients. Based on this data we hypothesize that the mRNA, miRNA, and protein composition of salivary EVs will provide valid biomarkers for early diagnosis and following disease progression in patients with AD and related neurodegenerative disorders. To test this hypothesis, we will use transcriptomic and proteomic approaches to define a set of RNA and protein biomarkers present in salivary EVs that predict an individual's risk of developing AD in Specific Aim 1. Specific Aim 2 will extend these investigations to identify RNA and protein biomarkers in salivary EVs isolated from individuals with FTD, PD, DLB, and ALS. In Specific Aim 3 we will determine the dynamics of changes in salivary EV composition during preclinical-to-AD clinical progression by following a cohort of cognitively normal individuals with positive amyloid β42 blood test over a period of 3-5 years. The data obtained in this project will allow us to identify biomarkers present in salivary EVs that can be used as a simple, noninvasive screening mechanism to detect patients at risk of developing AD during the preclinical phase when treatments may be more effective.