Unveiling the role of TAM-derived extracellular vesicles in glioma progression through Treg polarization and immune suppression.

In the context of gliomas, tumor-associated macrophages (TAMs) and regulatory T cells (Tregs) play crucial roles in shaping the tumor microenvironment (TME). This study focused on elucidating the mechanism by which TAM-derived extracellular vesicles (EVs) influence Treg differentiation and contribute to glioma progression. Through comprehensive single-cell RNA sequencing (scRNA-seq) analysis, the glioma TME was characterized by an abundance of TAMs exhibiting M2 polarization and increased Treg differentiation. Notably, TAM EVs were identified as potent inducers of Treg differentiation, with the downregulation of Bactericidal/Permeability-Increasing protein (BPI) being associated with this process. In vivo experiments utilizing a mouse model of glioma further demonstrated that TAM-derived EVs promoted glioma growth by enhancing Treg-mediated immunosuppression while dampening pro-inflammatory responses. This study highlights the critical role of TAM-derived EVs in modulating Treg differentiation and supporting glioma progression, suggesting that interventions targeting TAM EVs or regulating BPI expression could offer novel therapeutic avenues for combating immune suppression and inhibiting glioma development.