TMIC-27. Myeloid-driven axonogenesis bridges neural and immune remodeling in glioblastoma

Abstract Glioblastoma (GBM) is the most aggressive primary brain malignancy in adults, with median survival declining to 6-9 months after recurrence. While neuronal-glioma synaptogenesis has been associated with poor outcomes, the preceding mechanism of tumor-directed axonogenesis remains unclear. Neuropilin-2 (NRP2)—a transmembrane receptor involved in angiogenesis, immunosuppression, and axonal guidance—may contribute to tumor microenvironment (TME) remodeling that accelerates disease progression. NRP2 expression was profiled across immune, neuronal, glial, and tumor compartments in human GBM specimens. Mechanistic studies were conducted in syngeneic murine GBM models (CT-2A, SB28) using NRP2 knockdown, flow cytometry, Seahorse metabolic assays, immunofluorescence, western blotting, and in vivo imaging. Functional endpoints included neurite outgrowth, radiographic tumor progression, and survival. NRP2 was enriched in tumor-associated myeloid cells in both human and murine GBM. NRP2+ myeloid-derived suppressor cells (MDSCs) facilitated neurite extension toward glioma cells and amplified neurotrophic signaling; loss of NRP2+ MDSC activity abrogated neuronal axonogenesis towards tumor cells (P<0.001). Activation of NRP2 by VEGF-C and Semaphorin-3C induced IL-10 and BDNF production, enhancing axonogenesis (P<0.0001). Inhibition of NRP2 in vivo reversed immunosuppressive polarization with increased infiltration of CD86+MHCII+ myeloid cells and elevated CD8+ T cell IFN-γ expression, improved mitochondrial fitness in MDSCs and T cells, impaired neoangiogenesis on MR angiography, and reduced tumor-associated axonogenesis on diffusion tensor imaging tractography. Pharmacologic blockade of NRP2 significantly prolonged survival in both primary and recurrent GBM models (P<0.0001). Therefore, NRP2+ myeloid cells act as key mediators of axonogenesis in GBM through coordinated neuroimmune signaling. Targeting this pathway disrupts neuron-tumor crosstalk, enhances anti-tumor immunity, and improves survival, offering a novel therapeutic strategy at the intersection of cancer neuroscience and immunology.