Tumor-derived RPS19 engages C5AR1+ inflammatory macrophages to drive astrocyte reprogramming and glioblastoma progression

Abstract

Glioblastoma (GBM) is an incurable brain tumor with poor survival outcomes. Its progression and recurrence are strongly influenced by infiltrative growth of tumor cells and tumor microenvironment (TME) components, particularly tumor-associated macrophages (TAMs). To identify potential therapeutic targets for controlling GBM, we investigated how the ribosomal protein S19 (RPS19)–complement 5a receptor 1 (C5AR1) axis reprograms TAMs, promoting inflammation-mediated responses and tumor progression. To identify critical contributors for GBM progression, we collected single-cell RNA sequencing data from human GBM tumor masses and adjacent tissues, as well as from healthy brains and GL261-bearing mouse brains. The data were analyzed and validated using public GBM databases. Clinical specimens, in vitro , and in vivo approaches were conducted to elucidate underlying mechanisms and confirm therapeutic targets. Tumor-derived RPS19 and C5AR1 + TAMs are noted as key contributors to postoperative GBM progression. Trajectory and spatial transcriptomics revealed that C5AR1 + Inflammatory TAM1 emerged as a precursor of protumoral TAMs, whereas C5AR1 expression followed a trajectory similar to that of inflammatory TAM1 and was enriched around necrotic regions. Under stress conditions, tumor-released RPS19 selectively activates pro-inflammatory macrophages and microglia resulting in IL-1β upregulation via the Akt-PU.1/SPI1 axis. Increased IL-1β levels reprogram astrocytes toward A1-like phenotypes, contributing to neuroinflammation, cerebral edema, and upregulating astrocyte-derived tumor-supporting factors, such as CCL2, TGF-β1, and IL-6, further accelerating tumor growth. Pharmacological interruption of the RPS19-C5AR1 axis alleviated TAM-mediated inflammation, mitigated cerebral edema, and ultimately extended survival in an orthotopic GBM murine model. We elucidated a novel intercellular mechanism by which RPS19 drives GBM progression through IL-1β-mediated TME evolution. Thus, the RPS19–C5AR1 axis can be targeted to alleviate inflammation and cerebral edema, thereby improving clinical outcomes in GBM.