Glutamine metabolism keeps pathogenic hepatic CD4+ T cells in check.

Sawada et al. show that glutamine metabolism through glutaminolysis restrains O-GlcNAcylation and pathogenic inflammatory cytokine production by hepatic CD4+ T cells during MASLD. Glutamine supplementation restores hepatic glutamine availability and limits liver injury, and these findings reveal a tissue-specific metabolic checkpoint that restrains inflammatory T cell function during steatohepatitis.