Department of Veterinary Pathology, College of Veterinary Medicine, Iowa State University, Ames, IA, USA.
US Department of Agriculture, Virus and Prion Research Unit, National Animal Disease Center, Agricultural Research Service, Ames, IA, USA.
Vet Pathol. 2020 Jan;57(1):90-107. doi: 10.1177/0300985819861708. Epub 2019 Jul 22.
Mammalian transmissible spongiform encephalopathies (TSEs) display marked activation of astrocytes and microglia that precedes neuronal loss. Investigation of clinical parallels between TSEs and other neurodegenerative protein misfolding diseases, such as Alzheimer's disease, has revealed similar patterns of neuroinflammatory responses to the accumulation of self-propagating amyloids. The contribution of glial activation to the progression of protein misfolding diseases is incompletely understood, with evidence for mediation of both protective and deleterious effects. Glial populations are heterogeneously distributed throughout the brain and capable of dynamic transitions along a spectrum of functional activation states between pro- and antiinflammatory polarization extremes. Using a murine model of Rocky Mountain Laboratory scrapie, the neuroinflammatory response to prion infection was characterized by evaluating glial activation across 15 brain regions over time and correlating it to traditional markers of prion neuropathology, including vacuolation and PrP deposition. Quantitative immunohistochemistry was used to evaluate glial expression of iNOS and Arg1, markers of classical and alternative glial activation, respectively. The results indicate progressive upregulation of iNOS in microglia and a mixed astrocytic profile featuring iNOS expression in white matter tracts and detection of Arg1-positive populations throughout the brain. These data establish a temporospatial lesion profile for this prion infection model and demonstrate evidence of multiple glial activation states.
哺乳动物传染性海绵状脑病 (TSE) 表现出明显的星形胶质细胞和小胶质细胞激活,这先于神经元丢失。对 TSE 与其他神经变性蛋白错误折叠疾病(如阿尔茨海默病)之间的临床相似性的研究揭示了对自我传播淀粉样蛋白积累的类似神经炎症反应模式。胶质细胞激活对蛋白错误折叠疾病进展的贡献尚不完全清楚,有证据表明既有保护作用,也有有害作用。神经胶质细胞在大脑中呈异质分布,能够沿着从促炎到抗炎极化极端的功能激活状态谱进行动态转变。使用罗基山实验室羊瘙痒病的小鼠模型,通过评估朊病毒感染后的神经炎症反应,来研究神经胶质细胞的激活情况,包括随时间推移在 15 个脑区的变化,并将其与朊病毒神经病理学的传统标志物(空泡形成和 PrP 沉积)相关联。使用定量免疫组织化学方法来评估 iNOS 和 Arg1 的表达,这两个标志物分别代表经典和替代的神经胶质细胞激活。结果表明,小胶质细胞中 iNOS 的表达逐渐上调,星形胶质细胞呈现出混合表型,在白质束中出现 iNOS 表达,在大脑的各个区域都检测到 Arg1 阳性群体。这些数据为这种朊病毒感染模型建立了一个时空病变图谱,并证明了多种神经胶质细胞激活状态的存在。