Resolving selective vulnerability and disease progression in human Alzheimer's brain via single-cell RNA-seq

摘要 阿尔茨海默病(AD)的有效治疗方法迫在眉睫。现有方法在很大程度上 未能改善症状或改变疾病进展，部分原因是我们对 本病的发病机制。以前的神经病理学和神经成像研究对 建立阿尔茨海默病的组织病理学特征和特定脑区的受累。然而， 不同神经元和非神经元细胞类型对阿尔茨海默病及其潜在分子的选择性易感性 机制在很大程度上仍不清楚。我们假设神经细胞和非神经细胞的亚群 类型对阿尔茨海默病有明显的贡献，并建议使用人脑中的单细胞转录组学来识别 这些细胞类型和导致AD病理的潜在分子机制。尽管应用这一点 创新技术对人类大脑是具有挑战性的，人类AD大脑对于理解 不同细胞类型对疾病的贡献，识别最早的致病事件，揭示 神经保护途径，并定义了病理学的传播。我们将研究早期和晚期受影响的大脑 皮质区，包括内嗅觉、联合和初级感觉皮质，来自受试者 疾病进展的全过程(Braak期I-VI期)和年龄匹配的健康对照组。这一战略 将提供脆弱和有弹性的细胞类型及其转录组变化的综合图景， 以及随时间和跨大脑皮层区域变化的传播。在目标1中，我们将使用单核RNA- 对神经元、神经胶质细胞(小胶质细胞、星形胶质细胞和 少突胶质细胞)和血管细胞。在目标2中，我们将测试不同分子定义的假设 皮质和丘脑皮质投射神经元亚群选择性地易受 退化。在目标3中，我们将使用我们的新技术研究与tau病理相关的分子变化。 开发了纯化和描绘单个神经元的方法，这些神经元带有神经纤维缠结。这些研究将 生成第一个人类神经元的单细胞转录组图谱，并提供对 Tau介导的神经退行性变机制。共同努力，我们的研究将提供不偏不倚和强有力的 阿尔茨海默病中脆弱和弹性细胞类型的鉴定及其分子机制的深入研究 有选择性的漏洞。这些数据将为科学界提供宝贵的资源，以改进 基于细胞类型的疾病建模和药物发现。

ABSTRACT Effective therapies for Alzheimer’s disease (AD) are urgently needed. The existing approaches have largely failed to improve symptoms or modify disease progression, in part because of our incomplete understanding of the disease pathogenesis. Previous neuropathology and neuroimaging studies have been instrumental in establishing the histopathological hallmarks of AD and the involvement of specific brain regions. However, the selective vulnerability of distinct neuronal and non-neuronal cell types to AD and the underlying molecular mechanisms remain largely unknown. We hypothesize that subpopulations of neuronal and non-neuronal cell types contribute distinctively to AD and propose the use of single-cell transcriptomics in human brain to identify these cell types and the underlying molecular mechanisms leading to AD pathology. Although applying this innovative technology to human brain is challenging, human AD brain is crucial for understanding the contributions of distinct cell types to disease, identifying the earliest pathogenic events, uncovering neuroprotective pathways, and defining the spread of pathology. We will study early- and late-affected cerebral cortical regions, including entorhinal, association, and primary sensory cortices, from subjects encompassing the full spectrum of disease progression (Braak stages I–VI) and age-matched healthy controls. This strategy will provide a comprehensive landscape of the vulnerable and resilient cell types, their transcriptome changes, and the spread of changes over time and across cortical regions. In Aim 1 we will use single-nucleus RNA- sequencing for the unbiased identification and transcriptome profiling of neurons, glia (microglia, astrocytes, and oligodendrocytes), and blood vessel cells. In Aim 2 we will test the hypothesis that distinct molecularly defined subpopulations of cortico-cortical and cortico-thalamic projection neurons are selectively vulnerable to degeneration. In Aim 3 we will examine the molecular changes associated with tau pathology using our newly developed assay for purifying and profiling single neurons bearing neurofibrillary tangles. These studies will generate the first single-cell transcriptome profiling of human neurons with tangles and provide insight into the tau-mediated mechanisms of neurodegeneration. Together, our studies will provide an unbiased and robust identification of the vulnerable and resilient cell types in AD and insight into the molecular mechanisms underlying the selective vulnerabilities. These data will provide a valuable resource to the scientific community for improved cell-type-based disease modeling and drug discovery.