Plasma derived extracellular vesicle biomarkers of microglia activation in an experimental stroke model

作者：Austyn D. Roseborough, Sarah J. Myers, Reza Khazaee, Yuxin Zhu, Liang Zhao, Egidio Iorio, Fanny M. Elahi, Stephen Pasternak, Shawn N. Whitehead · 发表于：Journal of Neuroinflammation · 年份：2023 · DOI：10.1186/s12974-023-02708-x · 被引用次数：35 · 研究领域：Neuroinflammation and Neurodegeneration Mechanisms、Extracellular vesicles in disease、Immune cells in cancer

Abstract Chronic microglia activation post-stroke is associated with worse neurological and cognitive outcomes. However, measurement of microglia activation in vivo is currently limited. Plasma derived extracellular vesicles (EVs) are cell-specific indicators that may allow for non-invasive measurement of microglia phenotype. The aim of this study was to identify activation-state specific microglia EVs (MEVs) in vitro followed by validation in an experimental stroke model. Following pro-inflammatory activation, MEVs contain the microglia protein TMEM119 alongside increased expression of the Toll-like receptor 4 co-receptor CD14. Immunoprecipitation followed by fluorescent nanoparticle tracking analysis (ONI Nanoimager) was used to confirm the isolation of TMEM119 + /CD14 + EVs from rat plasma. Electron microscopy confirmed that TMEM119 and CD14 localize to the MEV membrane. To model ischemia, plasma was collected from 3-month wildtype Fischer344 rats prior to, 7 and 28 days after endothelin-1 or saline injection into the dorsal right striatum. Fluorescently labelled MEVs were directly measured in the plasma using nanoflow cytometry (Apogee A60 Microplus). We report a significant increase in circulating TMEM119 + /CD14 + EVs 28-days post-stroke in comparison to baseline levels and saline-injected rats, which correlated weakly with stroke volume. TMEM119 + /MHC-II + EVs were also increased post-stroke in comparison to baseline and saline-injected animals. This study is the firs...