Distinct macrophage and microglia function in ischemic stroke.

Abstract

This study aims to explore the characteristics and differentiation pathways of microglia and macrophages using single-cell transcriptome data from mouse stroke models. The clusters of microglia and macrophages in the middle cerebral artery occlusion model mouse brain were identified using the Seurat package. The signaling pathways were evaluated through Gene Ontology and the Kyoto Encyclopedia of Genes and Genomes analyses, while transcription factor activity was analyzed using DecoupleR. Monocle2 was employed to infer the differentiation trajectory of microglia and macrophages, exploring changes in gene expression patterns during their activation process using gene dynamics analysis. Additionally, the self-differential and overlapping subclusters of macrophages and microglia following cerebral ischemia were assessed, and CellChat was used to analyze differences in cell communication. Anoxygen-glucose deprivation model of BV2 microglia was established, and phagocytosis assays and real-time-quantitative PCR were conducted to evaluate the effects of FoxO1 knockdown on the phagocytic ability and inflammatory cytokine production of microglia. Microglia and macrophages showed significant functional changes following ischemic stroke. Microglia enhance their phagocytic capabilities, whereas macrophages exhibited a reduction in phagocytic function. The predominance of microglia in phagocytic and inflammatory pathways is primarily attributed to the differential expression of specific transcription factors, particularly FoxO1. Knockdown of FoxO1 significantly diminished the phagocytic ability of BV2 cells and increased the expression of the inflammatory cytokines CCL2, IFN-γ, and TNF. The transcription factor FoxO1 mediates the functional differences in phagocytosis and inflammatory responses between macrophages and microglia. Activation of FoxO1 can significantly enhance the phagocytic capacity of microglia while simultaneously reducing inflammatory responses, positioning it as a potential new target for the treatment of ischemic stroke.