PDF(Pubmed)
Abstract：
Age-associated deep-subcortical white matter lesions (DSCLs) are an independent risk factor for dementia, displaying high levels of CD68+ microglia. This study aimed to characterize the transcriptomic profile of microglia in DSCLs and surrounding radiologically normal-appearing white matter (NAWM) compared to non-lesional control white matter. CD68+ microglia were isolated from white matter groups (n = 4 cases per group) from the Cognitive Function and Ageing Study neuropathology cohort using immuno-laser capture microdissection. Microarray gene expression profiling, but not RNA-sequencing, was found to be compatible with immuno-LCM-ed post-mortem material in the CFAS cohort and identified significantly differentially expressed genes (DEGs). Functional grouping and pathway analysis were assessed using the Database for Annotation Visualization and Integrated Discovery (DAVID) software, and immunohistochemistry was performed to validate gene expression changes at the protein level. Transcriptomic profiling of microglia in DSCLs compared to non-lesional control white matter identified 181 significant DEGs (93 upregulated and 88 downregulated). Functional clustering analysis in DAVID revealed dysregulation of haptoglobin-haemoglobin binding (Enrichment score 2.5, p = 0.017), confirmed using CD163 immunostaining, suggesting a neuroprotective microglial response to blood-brain barrier dysfunction in DSCLs. In NAWM versus control white matter, microglia exhibited 347 DEGs (209 upregulated, 138 downregulated), with significant dysregulation of protein de-ubiquitination (Enrichment score 5.14, p < 0.001), implying an inability to maintain protein homeostasis in NAWM that may contribute to lesion spread. These findings enhance understanding of microglial transcriptomic changes in ageing white matter pathology, highlighting a neuroprotective adaptation in DSCLs microglia and a potentially lesion-promoting phenotype in NAWM microglia.
摘要：
年龄相关性皮质下深部白质病变(DSCLs)是痴呆的独立危险因素,显示高水平的CD68+小胶质细胞。这项研究旨在表征DSCL和周围放射学上正常出现的白质（NAWM）中小胶质细胞的转录组学特征。使用免疫激光捕获显微解剖从认知功能和衰老研究神经病理学队列的白质组(每组n=4例)中分离出CD68+小胶质细胞。微阵列基因表达谱分析，但不是RNA测序，在CFAS队列中发现与免疫LCM基因的死后材料相容，并鉴定出显著差异表达的基因(DEGs)。使用注释可视化和集成发现数据库（DAVID）软件评估功能分组和途径分析，并进行免疫组织化学以验证蛋白质水平的基因表达变化。与非病变对照白质相比，DSCL中小胶质细胞的转录组学分析鉴定出181个显着的DEG（93个上调，88个下调）。DAVID中的功能聚类分析显示结合珠蛋白-血红蛋白结合的失调（富集评分2.5，p=0.017），使用CD163免疫染色证实，提示DSCLs对血脑屏障功能障碍的神经保护性小胶质细胞反应。在NAWM和控制白质中，小胶质细胞表现出347个DEG(209个上调，138下调)，具有蛋白质去泛素化的显着失调（富集评分5.14，p<0.001），这意味着NAWM无法维持蛋白质稳态，这可能导致病变扩散。这些发现增强了对衰老白质病理学中小胶质细胞转录组变化的理解，强调DSCLs小胶质细胞的神经保护性适应和NAWM小胶质细胞的潜在损害促进表型。
