cRGD-Functionalized macrophage extracellular vesicles loaded with GSK2033 enhance T cell antitumor immunity in GBM by disrupting the LXR/ABCA1-Mediated Myelin lipid transfer axis.

Glioblastoma (GBM), the most aggressive adult primary brain tumor, faces lethal challenges due to its immunosuppressive microenvironment and blood-brain barrier (BBB) impedance. This study investigates how cRGD-functionalized macrophage-derived extracellular vesicles (cEV) loaded with the Liver X receptor (LXR) antagonist GSK2033 (cEV@GSK) enhance T cell-mediated antitumor immunity in GBM by targeting the LXR/ATP-binding cassette transporter A1 (Abca1) axis. Methods include isolating and cRGD-functionalizing RAW264.7 macrophage-derived extracellular vesicles, loading GSK2033 to form cEV@GSK, characterizing nanoparticles via TEM, size/zeta potential, and HPLC; evaluating BBB penetration, cellular uptake, and cytotoxicity in vitro; assessing in vivo distribution, antitumor efficacy, and biosafety using an orthotopic GBM mouse model; and analyzing mechanisms via proteomics and single-cell RNA sequencing (scRNA-seq), with T cell-LLM-GL261 co-cultures validating KLRB1 function. Results show cEV@GSK effectively crosses the BBB, exhibits biosafety, and significantly suppresses tumor growth. Mechanistically, it blocks the LXR/Abca1 axis, reducing myelin lipid transfer from lipid-laden macrophages (LLMs) and downregulating T cell KLRB1, thereby augmenting T cell activation and antitumor activity. Conclusion: cEV@GSK enhances T cell immunity by disrupting the LXR/Abca1 axis and LLM-mediated lipid transfer, offering a novel GBM immunotherapy strategy.