Counterbalancing O-GlcNAcylation and STAT3 Phosphorylation in Ventral Tegmental Area Dopaminergic Neurons Mediates...

Acute stressors, significant risk factors for mood disorders, increase anxiety and reduce reward sensitivity. However, the underlying neuroadaptive mechanisms remain unclear. Here, it is shown that acute restraint stress upregulates Signal Transducer and Activator of Transcription 3 (STAT3) signaling and O-GlcNAcylation in ventral tegmental area (VTA) dopaminergic (DAergic) neurons. Multi-omics analyses in O-linked N-acetylglucosamine transferase (OGT) conditional knockout (cKO) mice reveal a counterbalancing mechanism between O-GlcNAcylation and STAT3^Ser727 phosphorylation. In vivo fiber-optic recordings and behavioral experiments demonstrate that STAT3^Ser727 phosphorylation mediates the suppression of DAergic neuronal activity and reward sensitivity, as well as the increased anxiety induced by acute restraint stress. Conversely, the upregulation of O-GlcNAcylation in the VTA DAergic neurons prevents these effects. Furthermore, Gabbr2 and Gabrb3 expression is upregulated in the VTA of Ogt cKO mice, whereas the phosphorylation of STAT3^Ser727 in the DAergic neurons is required for the upregulation of Gabbr2 and Gabrb3 induced by acute restraint stress. These findings highlight the dynamic and counterbalancing post-translational modifications occurring in the VTA to maintain dopaminergic and emotional homeostasis, offering new insights into neuronal and behavioral responses to acute stress.