Single cell and spatial atlas of macrophage and astrocyte interactions in glioblastoma.

Glioblastoma (GBM) exhibits pronounced intratumoral heterogeneity, yet the interactions between macrophages and astrocyte-like (AC-like) cells remain incompletely understood. We analyzed single-cell RNA sequencing data from 10 GBM patients, performing clustering with Seurat and Harmony, copy number variation to distinguish malignant cells, and trajectory inference to map lineage relationships. CellChat was applied to predict intercellular signaling, while CellTrek reconstructed spatial co-localization. Prognostic significance of identified key subpopulations was evaluated using Cox regression analysis. Thirteen cell subtypes were identified in GBM, including four macrophage clusters (e.g., Macro_CCL3, Macro_C1QL1) and eight AC-like clusters (e.g., AClike_RGCC, AClike_SLC7A5). Macro_C1QL1 and AClike_SLC7A5 were enriched in malignant regions and correlated with poor prognosis. Intercellular communication analysis indicated that Macro_C1QL1 and AClike_SLC7A5 cells engage in strengthened APP-CD74 signaling, emphasizing the involvement of tumor-specific CypA and APP pathways. Spatial mapping confirmed their co-localization in tumor-dense areas, supporting niche-specific interactions. This study provides an integrated single-cell and spatial characterization of macrophage and AC-like cell crosstalk in GBM, identifying key signaling networks and potential therapeutic targets.