M2-like GAMs secreting CSTA drive glioblastoma progression via the ITGB4-TGFB1 feedback axis.

BACKGROUND: Tumor microenvironment (TME) remodeling is a hallmark of gliomas. Glioma-associated macrophage/microglia (GAMs), the most abundant cellular component in the glioma TME, play critical roles in driving glioma progression, though the specific GAM subsets and their regulatory mechanisms remain unclear. This study investigates glioma-GAM crosstalk, identifies GAM subsets that regulate glioblastoma (GBM) progression, clarifies the role and mechanism of CSTA, and explores its clinical relevance. METHODS: With bulk RNA-seq and scRNA-seq datasets, a CSTA⁺ M2-like GAM subset was identified. In vitro and in vivo models confirmed CSTA’s pro-oncogenic effect on GBM. In vitro studies explored the mechanisms of CSTA upregulation in M2-like GAMs and its role in advancing GBM progression. Mass spectrometry and molecular docking predicted and validated CSTA’s interacting protein targets. Clinical cohort analyses evaluated the relationship between CSTA and glioma grades. RESULTS: M2-like polarization activates p44/p42 (ERK1/2) phosphorylation in the MAPK pathway, upregulating the c-JUN/c-FOS (AP-1) transcription complex and promoting CSTA expression in GAMs. CSTA binds to ITGB4 at glutamate residue 88, activating downstream NF-κB and MAPK signaling in GBM cells to drive progression. Moreover, the CSTA-ITGB4 axis induces GBM cells to secrete TGFB1, which recruits M2-like GAMs and exacerbates TME immunosuppression. Additionally, CSTA levels in peripheral blood and cerebrospinal fluid (CSF) correlate positively with glioma grade. CONCLUSIONS: CSTA⁺ M2-like GAMs promote GBM malignancy via the CSTA-ITGB4 axis, activating downstream NF-κB and MAPK signaling and forming a TGFB1-mediated positive feedback loop. Notably, CSTA correlates with glioma grades and has independent prognostic and potential therapeutic value.