Define molecular events driving selective neuronal death in multiple neurodegenerative diseases by snRNA-seq

项目摘要 尽管经过几十年的研究，目前阿尔茨海默氏症神经退行性变的机制 帕金森病（PD）和阿尔茨海默病（AD）仍然存在争议， 预防、减缓或阻止疾病进展。神经退行性疾病有两个基本的 一般特征1)与疾病相关的病理学只影响特定的 神经元（“选择性神经元的能力”）; 2）病理学随时间而变化，影响更大 以一种刻板和可预测的方式。发现了调节 神经元对变性的这种不同敏感性为发现 新的药物靶点和有前途的神经保护治疗策略的发展。 然而，选择性神经元和区域脆弱性的潜在机制一直是 由于我们区分不同神经元亚群的能力有限，因此难以解剖。 SN中多巴胺能神经元的丢失是PD的标志，其是帕金森病的基础。 运动症状，如僵硬和震颤。在AD的SN中也发生神经元损失[8，9]， 然而，通常没有共同发生的帕金森运动症状。多巴胺能神经元 SN是高度异质性的[10]，PD中多巴胺能神经元的丢失是 在不同轴上的异质性[11-14]。目前还不清楚是否同一群神经元 在AD和PD中丢失，以及神经元丢失的机制是否在AD和PD之间共享。 两种疾病。神经炎症-激活神经免疫细胞（如小胶质细胞）， 促炎状态-是AD和PD中共有的病理贡献者。但 不同小胶质细胞亚群的分子特性和神经炎症在神经胶质细胞增殖中的作用 选择性神经元死亡仍不清楚。因此，我们建议使用单核RNA-seq （snRNA-seq），一种无偏倚的方法来鉴定和表征不同的细胞群体， 组织，剖析选择性神经元死亡的机制。具体来说，我们的 目标1：表征和验证细胞异质性，细胞和 AD、PD黑质脑组织神经元和小胶质细胞的转录组学变化 患者和年龄匹配的对照组。目的2：剖析细胞组成的机制 以及AD和PD中的转录组失调。我们的研究将提供1）分子标记 以及用于靶向神经元和小胶质细胞亚群分离和操作的工具; 2）更好地 了解不同神经元和小胶质细胞亚群的动态变化， AD和PD中的转录组学变化和假定的调节机制; 3）高- 有信心将新的候选基因和途径作为开发有效免疫疗法的目标 或神经保护策略。

Project Summary Despite decades of research, currently the mechanisms of neurodegeneration in Alzheimer’s disease (AD) and Parkinson Disease (PD) remain controversial and there are no therapies can prevent, slow, or halt disease progression. Neurodegenerative diseases have two fundamental general characteristics. 1) The pathology associated with the disease only affects particular neurons (‘selective neuronal vulnerability’); 2) The pathology worsens with time and impacts more regions in a stereotypical and predictable fashion. The discovery of key pathways that regulate this differential susceptibility of neurons to degeneration holds great potential for the discovery of novel drug targets and the development of promising neuroprotective treatment strategies. However, the mechanisms underlying selective neuronal and regional vulnerability have been difficult to dissect because of our limited ability to distinguish different neuronal subpopulations. Loss of dopaminergic neurons in the SN is a hallmark of PD which underlies the parkinsonian motor symptoms such as rigidity and tremor. Neuronal loss also occurs in the SN of AD [8, 9], however, often without co-occurring parkinsonian motor symptoms. Dopaminergic neurons within the SN are highly heterogeneous [10] and the loss of the dopaminergic neurons in PD is heterogeneous across different axes [11-14]. It is unclear whether the same population of neurons were lost in AD and PD and whether the mechanisms of neuronal loss are shared between the two diseases. Neuroinflammation - activation of the neuroimmune cells (e.g. microglia) into proinflammatory states - are shared pathological contributors in AD and PD. However, the molecular identity of different microglia subpopulations and the role of neuroinflammation in the selective neuronal death remain unclear. Therefore, we propose to use single nucleus RNA-seq (snRNA-seq), an unbiased approach to identify and characterize distinct cell populations in tissues, to dissect the mechanisms underlying selective neuronal death. Specifically, our specific aims are: Aim 1: Characterize and validate cellular heterogeneity, cellular and transcriptomic changes of neuron and microglia from the SN brain tissues of AD, PD patients and age-matched controls. Aim 2: Dissect the mechanisms of cell composition and transcriptome dysregulation in AD and PD. Our study will provide 1) molecular markers and tools for targeted neuronal and microglia subpopulation isolation and manipulation; 2) better understanding of the dynamic change of different neuronal and microglia subpopulation, their transcriptomic changes and the putative regulatory mechanisms in AD and PD; 3) high- confidence new candidate genes and pathways as targets to develop effective immunotherapies or neuroprotective strategies.