O-GlcNAc Transferase Suppresses Inflammation and Necroptosis by Targeting Receptor-Interacting Serine/Threonine-Protein Kinase 3

Elevated glucose metabolism in immune cells represents a hallmark feature of many inflammatory diseases, such as sepsis. However, the role of individual glucose metabolic pathways during immune cell activation and inflammation remains incompletely understood. Here, we demonstrate a previously unrecognized anti-inflammatory function of the O-linked β-N-acetylglucosamine (O-GlcNAc) signaling associated with the hexosamine biosynthesis pathway (HBP). Despite elevated activities of glycolysis and the pentose phosphate pathway, activation of macrophages with lipopolysaccharide (LPS) resulted in attenuated HBP activity and protein O-GlcNAcylation. Deletion of O-GlcNAc transferase (OGT), a key enzyme for protein O-GlcNAcylation, led to enhanced innate immune activation and exacerbated septic inflammation. Mechanistically, OGT-mediated O-GlcNAcylation of the serine-threonine kinase RIPK3 on threonine 467 (T467) prevented RIPK3-RIPK1 hetero- and RIPK3-RIPK3 homo-interaction and inhibited downstream innate immunity and necroptosis signaling. Thus, our study identifies an immuno-metabolic crosstalk essential for fine-tuning innate immune cell activation and highlights the importance of glucose metabolism in septic inflammation. [Display omitted] •LPS treatment causes a decrease in HBP activity and protein O-GlcNAcylation•OGT deficiency increases activation of innate immune response and necroptosis•O-GlcNAcylation of RIPK3 on T467 inhibits RIPK3-RIPK1 and RIPK3-RIPK3 interaction The role of individual glucose metabolic pathways in innate immunity remains largely unknown. Li et al. demonstrate that attenuated O-linked β-N-acetylglucosamine (O-GlcNAc) signaling enhances TLR-induced innate immune response and necroptosis. Mechanistically, O-GlcNAcylation of the kinase RIPK3 blocks RHIM-domain-mediated protein interaction and downstream signaling activation.