Glucose-driven histone lactylation promotes the immunosuppressive activity of monocyte-derived macrophages in brain tumors [RNA-seq]

Macrophages are critical components of the immunosuppressive microenvironment that restrict anti-cancer immunity in glioblastoma (GBM). However, how GBM shapes the regulatory function of macrophages remains elusive. Here, we report that monocyte-derived macrophages (MDM), but not yolk-sac derived microglia (MG), exhibited potent immunosuppressive activity, which was mediated by a population of glycolytic GLUT1+MDM, in an IL10-dependent manner. GBM-derived factors reprogrammed MDM towards glycolytic cells with enhanced avidity for glucose, which was mostly used to generate lactate. In turn, intracellular lactate caused lactylation of histone lysine residues that promoted MDM immunosuppressive activity via regulation of Il10 expression. GBM-primed activation of PERK supported glucose metabolism and regulated GLUT1 expression through ATF4 in MDM. PERK-deletion in MDM abrogated histone lactylation and suppressive activity, thereby promoting polyfunctional T cell-infiltration of tumors. In combination with immunotherapy, PERK-deletion blocked GBM progression. Our study demonstrates that glucose-driven histone lactylation controls MDM immunosuppressive function; all in a PERK-dependent manner. Overall design: To dissect the mechanism responsible for the immunosuppression activity of macrophage, RNA-seq comparing transcriptomic profile of MG (F4/80+CD11b+CD45loLY6Clo/-LY6G-CD49dlo/-) versus BMDM (F4/80+CD11b+CD45+LY6Clo/-LY6G-CD49dhigh) was performed. MG and BMDM were FACS-sorted from isogenic GL261 brain tumors established orthotopically in the mouse brain.