Decoding monocyte signatures in ischemic stroke: A multi-scale transcriptomic approach

Monocytes play a crucial role in post-stroke immune infiltration, yet the intricate immune regulatory networks they orchestrate in ischemic stroke remain poorly understood. This knowledge gap has hindered the development of targeted monocyte-based therapies for stroke. Here, we used a multi-omics approach combining single-cell and bulk transcriptomics. CellChat analysis revealed intercellular communication networks, while key genes were identified and predictive models built through Lasso regression. Immune cell infiltration dynamics were quantified using single-sample gene set enrichment analysis. Gene set enrichment analysis and gene set variation analysis identified disease-regulated pathways of core genes. MicroRNA networks and transcription factors were investigated using mircode and RcisTarget. Experimental validation was performed using oxygen-glucose deprivation and transient middle cerebral artery occlusion models, focusing on the influence of abhydrolase domain-containing protein 2 on monocyte function. We observed significantly elevated monocyte content in stroke brain tissue samples, and identified key monocyte genes associated with immune inflammation, chemokine signaling, and cell receptor function. A robust seven-gene predictive model for ischemic stroke was developed. CD274 strongly correlated with these seven genes, suggesting a potential immunomodulatory axis. In vivo transient middle cerebral artery occlusion experiments validated the predictive value of key genes. In vitro studies demonstrated that abhydrolase domain-containing protein 2 overexpression enhanced monocyte proliferation and phagocytic activity post-oxygen-glucose deprivation while reducing reactive oxygen species generation. In conclusion, this study maps post-stroke monocyte communication networks, identifies key signaling pathways, identifies regulatory mechanisms, and validates the functional importance of key genes, particularly abhydrolase domain-containing protein 2. These findings provide a foundation for developing targeted immunomodulatory therapies and precision diagnostics in ischemic stroke management.