Single-cell RNA sequencing reveals the evolution of the immune landscape during perihematomal edema progression after intracerebral hemorrhage

Background Perihematomal edema (PHE) after post-intracerebral hemorrhage (ICH) has complex pathophysiological mechanisms that are poorly understood. The complicated immune response in the post-ICH brain constitutes a crucial component of PHE pathophysiology. In this study, we aimed to characterize the transcriptional profiles of immune cell populations in human PHE tissues and explore the microscopic differences between different types of immune cells. Methods ScRNA sequencing (scRNA-seq) was used to map immune cell populations within comprehensively resected PHE samples collected from patients at different stages after ICH. Results We established, for the first time, a comprehensive landscape of diverse immune cell populations in human PHE tissue at a single-cell level. Our study identified 12 microglial and five neutrophil subsets in human PHE tissue. What’s more, we discovered that the SPP1 pathway served as the basis for self-communication between microglia subclusters during the progression of PHE. Additionally, we traced the trajectory branches of different neutrophil subtypes. We also demonstrated that microglia-produced OPN could regulate the immune environment in PHE by interacting with CD44 cells. Conclusions As a result of our research, we have gained valuable insight into the immunomicroenvironment within PHE tissue, which could potentially be used to develop novel treatment modalities for ICH.