Metabolic Inhibitors of O-GlcNAc Transferase That Act In Vivo Implicate Decreased O-GlcNAc Levels in Leptin-Mediated Nutrient Sensing.

O-Linked glycosylation of serine and threonine residues of nucleocytoplasmic proteins with N-acetylglucosamine (O-GlcNAc) residues is catalyzed by O-GlcNAc transferase (OGT). O-GlcNAc is conserved within mammals and is implicated in a wide range of physiological processes. Herein, we describe metabolic precursor inhibitors of OGT suitable for use both in cells and in vivo in mice. These 5-thiosugar analogues of N-acetylglucosamine are assimilated through a convergent metabolic pathway, most likely involving N-acetylglucosamine-6-phosphate de-N-acetylase (NAGA), to generate a common OGT inhibitor within cells. We show that of these inhibitors, 2-deoxy-2-N-hexanamide-5-thio-d-glucopyranoside (5SGlcNHex) acts in vivo to induce dose- and time-dependent decreases in O-GlcNAc levels in various tissues. Decreased O-GlcNAc correlates, both in vitro within adipocytes and in vivo within mice, with lower levels of the transcription factor Sp1 and the satiety-inducing hormone leptin, thus revealing a link between decreased O-GlcNAc levels and nutrient sensing in peripheral tissues of mammals.