LCN2+ Astrocytes Mark a Pro-inflammatory Astrocyte State Associated with Secondary Brain Injury After Cerebral Venous Thrombosis

Cerebral venous thrombosis (CVT) is a cerebrovascular disorder with unique pathophysiological characteristics. Although the mortality rate during the acute phase has declined in recent years, the cellular mechanisms underlying secondary brain injury and long-term neurological dysfunction after CVT remain poorly understood [1,2]. In this study, we performed single-cell RNA sequencing of brain tissues from a murine CVT model to systematically characterize the cellular landscape following CVT and identified a reactive astrocyte state characterized by high expression of Lcn2. This astrocyte subset was markedly enriched after CVT. Notably, despite the absence of significant changes in the overall proportion of astrocytes, this population exhibited enhanced inflammatory/cytokine response signatures, ferroptosis-related stress responses, and vascular-immune microenvironment remodeling programs, suggesting that the major alteration of astrocytes after CVT is driven primarily by state transition rather than cellular expansion. Pseudotime trajectory analysis further demonstrated that Lcn2+ astrocytes were predominantly localized at the late stage of the trajectory and displayed sustained upregulation of multiple inflammation- and stress-associated genes, supporting their characterization as a late-stage reactive astrocyte state under CVT conditions. Cell-cell communication analysis revealed extensive predicted interactions between this subset and myeloid cells, vascular-associated cells, as well as neuronal/synaptic populations, indicating its potential involvement in dynamic remodeling of the lesion microenvironment. Cross-model integration analysis further revealed the presence of Lcn2-high astrocytes in the middle cerebral artery occlusion (MCAO) model; however, their expression breadth and intensity were generally weaker than those observed in CVT, suggesting that this cellular state may represent a common reactive framework following cerebrovascular obstruction, while being particularly pronounced in CVT. Furthermore, genetic deletion of LCN2 alleviated CVT-induced brain tissue injury in vivo, providing functional evidence supporting the detrimental role of the LCN2-associated pathological state. Collectively, our study identifies a distinct Lcn2-high reactive astrocyte state after CVT that is closely associated with inflammatory amplification, ferroptosis-related stress, and microenvironmental remodeling. These findings provide new cellular insights into the mechanisms underlying secondary brain injury after CVT and highlight potential targets for therapeutic intervention.