Zoonotic Diseases and Special Pathogens, National Microbiology Laboratory, Canadian Science Centre for Human and Animal Health, Public Health Agency of Canada, Winnipeg, Manitoba, Canada.
Viral Diseases, National Microbiology Laboratory, Canadian Science Centre for Human and Animal Health, Public Health Agency of Canada, Winnipeg, Manitoba, Canada.
Sci Rep. 2019 Jan 31;9(1):1099. doi: 10.1038/s41598-018-37715-z.
Multiple cell types and complex connection networks are an intrinsic feature of brain tissue. In this study we used expression profiling of specific microscopic regions of heterogeneous tissue sections isolated by laser capture microdissection (LCM) to determine insights into the molecular basis of brain pathology in prion disease. Temporal profiles in two mouse models of prion disease, bovine spongiform encephalopathy (BSE) and a mouse-adapted strain of scrapie (RML) were performed in microdissected regions of the CA1 hippocampus and granular layer of the cerebellum which are both enriched in neuronal cell bodies. We noted that during clinical disease the number of activated microglia and astrocytes that occur in these areas are increased, thereby likely diluting the neuronal gene expression signature. We performed a comparative analysis with gene expression profiles determined from isolated populations of neurons, microglia and astrocytes to identify transcripts that are enriched in each of these cell types. Although the incubation periods of these two models are quite different, over 300 days for BSE and ~160 days for RML scrapie, these regional microdissections revealed broadly similar profiles. Microglial and astrocyte-enriched genes contributed a profound inflammatory profile consisting of inflammatory cytokines, genes related to phagocytosis, proteolysis and genes coding for extracellular matrix proteins. CA1 pyramidal neurons displayed a net upregulation of transcription factors and stress induced genes at pre-clinical stages of disease while all tissues showed profound decrease of overlapping genes related to neuronal function, in particular transcripts related to neuronal communication including glutamate receptors, phosphatase subunits and numerous synapse-related markers. Of note, we found a small number of genes expressed in neurons that were upregulated during clinical disease including, COX6A2, FZD9, RXRG and SOX11, that may be biomarkers of neurodegeneration.
多种细胞类型和复杂的连接网络是脑组织的固有特征。在这项研究中，我们使用通过激光捕获显微切割（LCM）分离的异质组织切片的特定微观区域的表达谱分析，以确定对朊病毒病中脑病理学分子基础的深入了解。在两种朊病毒病的小鼠模型中，牛海绵状脑病（BSE）和小鼠适应的瘙痒病株（RML）进行了时间曲线分析，分别在富含神经元细胞体的 CA1 海马体和小脑颗粒层的显微切割区域进行。我们注意到，在临床疾病期间，这些区域中发生的活化小胶质细胞和星形胶质细胞的数量增加，从而可能稀释神经元基因表达特征。我们与从分离的神经元、小胶质细胞和星形胶质细胞群体中确定的基因表达谱进行了比较分析，以鉴定在每种细胞类型中富集的转录本。尽管这两种模型的潜伏期差异很大，BSE 为 300 多天，RML 瘙痒病为 160 天左右，但这些区域性显微切割揭示了广泛相似的图谱。小胶质细胞和星形胶质细胞富集的基因贡献了一个深刻的炎症特征，包括炎症细胞因子、与吞噬作用、蛋白水解和细胞外基质蛋白编码相关的基因。在疾病的临床前阶段，CA1 锥体神经元显示出转录因子和应激诱导基因的净上调，而所有组织都显示出与神经元功能相关的重叠基因的明显减少，特别是与神经元通讯相关的转录本，包括谷氨酸受体、磷酸酶亚基和许多突触相关标记物。值得注意的是，我们发现了一小部分在神经元中表达的基因在临床疾病期间上调，包括 COX6A2、FZD9、RXRG 和 SOX11，它们可能是神经退行性变的生物标志物。
