Comprehensive insight on immune landscape in intracerebral hemorrhage patients with single-cell RNA sequencing: from blood to hematoma

BACKGROUND: As limited medical interventions proved efficacy in intracerebral hemorrhage (ICH), the mechanisms underlying primary and secondary tissue injury remain poorly understood based on hematoma. In this study, we aimed to investigate the transcriptional profiles of immune cells from hematoma samples derived from ICH patients, which was rarely focused before. METHODS: Single cell RNA sequencing (scRNA-seq) was performed on hematoma and blood samples derived from ICH patients, with blood samples from healthy volunteers serving as a control. Subsequent comprehensive analyses, including cell-cell communication and trajectory inference, were conducted to provide a detailed understanding of immune cell characteristics in ICH. RESULTS: Hematoma and blood samples were derived from four ICH patients, with blood samples from three healthy volunteers as control. At the single-cell level, three major immune cell types were identified, with neutrophils playing a predominant role. Subtypes of these immune cells were further characterized based on their profiles in hematoma and blood samples. The role of Toll-like receptor 4 in hematoma in ICH was further investigated from the perspective of immune inflammation and metabolism. CONCLUSION: This study offers a comprehensive overview of the immune cell landscape in ICH, derived from hematoma and blood samples, which has been rarely reported. The dynamic inflammatory processes involving distinct immune cell types were further elucidated, and provides potential therapeutic targets for future interventions.