Does Microglial Activation Influence Propagation of Alpha-synuclein Pathology

小胶质细胞激活是否影响α-突触核蛋白病理学的传播

• 批准号: 9117882
• 负责人: Patrik Brundin
• 金额: $ 28.5万
• 依托单位: VAN ANDEL RESEARCH INSTITUTE
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-02-15 至 2018-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9117882
• 关键词: Ablation; Affect; Animal Model; Anti-Inflammatory Agents; Anti-inflammatory; Brain; Cell Culture Techniques; Cells; Chemicals; Clinical; Clinical Trials; Corpus striatum structure; Data; Development; Disease; Disease Progression; Embryo; Environment; Extracellular Space; Foundations; Future; Genetic; Goals; Human; Immunotherapy; In Vitro; Inflammation; Inflammation Mediators; Inflammatory; Injection of therapeutic agent; Interleukin-4; Intervention; Knowledge; Lead; Lewy Bodies; Lipopolysaccharides; Macrophage Colony-Stimulating Factor Receptor; Measures; Mediating; Microglia; Midbrain structure; Mission; Modeling; Molecular Target; Monitor; Morbidity - disease rate; Mus; National Institute of Neurological Disorders and Stroke; Nature; Nerve; Neurites; Neurodegenerative Disorders; Neurons; Outcome; Parkinson Disease; Pathogenesis; Pathology; Pattern; Phenotype; Phosphotransferases; Play; Process; Public Health; Quality of life; Reading; Research; Role; Seeds; Stimulus; Testing; Translating; Transplantation; United States National Institutes of Health; Work; alpha synuclein; base; design; dopaminergic neuron; extracellular; improved; in vivo; in vivo Model; innovation; mouse model; neuroinflammation; neuropathology; novel; overexpression; prion-like; public health relevance; relating to nervous system; therapy development; tool; uptake

 DESCRIPTION (provided by applicant): Neuron-to-neuron propagation of α-synuclein (α-syn) aggregates is thought to contribute to the pathogenesis of Parkinson's disease (PD) and underlie the stereotypical progression pattern of α-syn neuropathology. This postulate suggests that aggregated α-syn transfers from one neuron to another where it seeds further α-syn aggregation. However, it is not known how microglia influence this process, and how specific microglia activation states that occur upon inflammation affect α-syn transfer. To fill this gap i knowledge we developed a unique mouse model that allows us to monitor α-syn prion-like propagation between neurons. Our in vivo paradigm involves transplantation of embryonic midbrain neurons into the striatum of a mouse overexpressing human α- syn and allows the manipulation of microglia (i.e. ablation or specific activation). In this novel model, the presence of human α-syn within the grafted mouse cells (initially devoid of human α-syn) is used as a read-out for α-syn transfer. Based on our preliminary data we hypothesize that under normal conditions, microglia take up α-syn from the extracellular space, resulting in reduced α-syn transfer from neuron to neuron. We also hypothesize that α-syn accumulates in microglia following lipopolysaccharide treatment, as lipopolysaccharide -activated microglia have reduced proteolytic capacity whereas Interleukin 4-induced microglia effectively reduce the pool of extracellular α-syn, and thereby mitigate α-syn transfer from neuron to neuron. Two specific aims will be pursued to test this hypothesis: 1) Determine how the absence of microglia affects neuron-to-neuron transfer of α-syn; and 2) Determine how the presence of lipopolysaccharide-induced vs Interleukin 4-induced activated microglia affects the rate of neuron-to-neuron transfer of α-syn. First, we will monitor if the absence of microglia results in a different degre of α-syn cell-to-cell transfer using our unique in vivo model of cell-to-cell transfer. Second, we wil assess the transfer of α-syn into grafted neurons in the context of distinct microglial phenotypes lipopolysaccharide or Interleukin 4 injection will be used to stimulate these differential phenotypes. Our approach is innovative because it allows us to assess the interaction between two factors (inflammation and α-syn propagation) both considered to play key roles in PD pathogenesis in a single animal model, and we can define outcomes using unbiased, automated and quantitative measures of neuropathology. We predict that the absence of microglia will translate to increased neuron-to-neuron transfer of α-syn and that the nature of microglial activation will affect the accumulation of α-syn within microglia. Ultimately, the proposed research will result in an innovative and valid model of α-syn pathology propagation with the potential to facilitate the development of disease-modifying therapies based on treatments that modulate inflammation.

 描述（由申请人提供）：α-突触核蛋白（α-syn）聚集体的神经元到神经元传播被认为有助于帕金森病（PD）的发病机制，并且是 α-syn 神经病理学的典型进展模式的基础。这一假设表明聚集的 α-syn 从一个神经元转移到另一个神经元，在那里它引发进一步的 α-syn 聚集。然而，目前尚不清楚小胶质细胞如何影响这一过程，以及炎症时发生的特定小胶质细胞激活状态如何影响 α-syn 转移。为了填补这一知识空白，我们开发了一种独特的小鼠模型，使我们能够监测神经元之间的 α-syn 朊病毒样传播。我们的体内范例涉及将胚胎中脑神经元移植到过度表达人类α-syn的小鼠纹状体中，并允许操纵小胶质细胞（即消融或特异性激活）。在这个新颖的模型中，存在 移植小鼠细胞内的人类 α-syn（最初不含人类 α-syn）被用作 α-syn 转移的读数。根据我们的初步数据，我们假设在正常条件下，小胶质细胞从细胞外空间吸收 α-syn，导致神经元之间的 α-syn 转移减少。我们还假设脂多糖处理后 α-syn 在小胶质细胞中积累，因为脂多糖激活的小胶质细胞蛋白水解能力降低，而白细胞介素 4 诱导的小胶质细胞有效减少细胞外 α-syn 库，从而减轻 α-syn 从神经元到神经元的转移。我们将追求两个具体目标来检验这一假设：1）确定小胶质细胞的缺失如何影响 α-syn 的神经元间转移； 2) 确定脂多糖诱导与白细胞介素 4 诱导的活化小胶质细胞的存在如何影响 α-syn 的神经元间转移速率。首先，我们将使用我们独特的细胞间转移体内模型来监测小胶质细胞的缺失是否会导致不同程度的 α-syn 细胞间转移。其次，我们将在不同的小胶质细胞表型的背景下评估 α-syn 转移到移植神经元中，脂多糖或白细胞介素 4 注射将用于刺激这些差异表型。我们的方法是创新的，因为它使我们能够评估两个因素（炎症和 α-syn 传播）之间的相互作用，这两个因素被认为在单一动物模型中的 PD 发病机制中发挥关键作用，并且我们可以使用神经病理学的无偏见、自动化和定量测量来定义结果。我们预测，小胶质细胞的缺失将导致 α-syn 的神经元间转移增加，并且小胶质细胞激活的性质将影响小胶质细胞内 α-syn 的积累。最终，拟议的研究将产生一种创新且有效的 α-syn 病理学传播模型，有可能促进基于调节炎症治疗的疾病缓解疗法的开发。