Research progress on the mechanisms of microglial extracellular vesicles affecting the prognosis of ischemic stroke

Ischemic stroke is the major type of stroke and one of the main causes of morbidity, mortality, and long-term disability worldwide. Microglia play a complex and crucial role in stroke. They are the primary immune cells in the brain and can rapidly respond to the pathological changes caused by stroke. They promote neuroprotection and repair after ischemic stroke through various mechanisms, such as activation and polarization, dynamic interactions with other cells (neurons, astrocytes, oligodendrocytes, vascular endothelial cells, etc.), and phagocytosis to clear dead cell debris. Among the multiple pathways through which microglia exert their neuroprotective effects, the secretion of extracellular vesicles is one of the most important. The focus of this review is to analyze the latest progress in research on ischemic stroke related to microglia-derived extracellular vesicles, discuss their mechanisms of action, and provide new strategies for improving stroke prognosis. To obtain relevant articles, we conducted a comprehensive search in Pubmed and Web of Science, with keywords related to ischemic stroke and microglia-derived extracellular vesicles or exosomes. A total of 59 articles were included in the review. Existing studies have shown that after a stroke occurs, microglia release extracellular vesicles containing proteins, nucleic acids, metabolites, etc. These vesicles target corresponding receptor cells and can slow down the development of stroke and improve stroke outcomes through various means, such as reducing neuronal apoptosis, inhibiting neuronal autophagy, suppressing neuronal ferroptosis, preventing neuronal pyroptosis, alleviating inflammatory responses, reducing glial scar formation, promoting myelin regeneration and repair, and facilitating blood-brain barrier repair.