A neuroimmune pathway drives bacterial infection

Pathogen-induced septic death presents a substantial public health challenge, with its neuroimmune mechanisms largely unexplored. Our study investigates neurotransmitter modulation of ACOD1 expression, a regulator of immunometabolism activated by bacterial lipopolysaccharide (LPS). Screening neurotransmitters identifies dopamine as a potent inhibitor of LPS-induced ACOD1 expression in innate immune cells. Mechanistically, DRD2 forms a complex with TLR4, initiating MAPK3-dependent CREB1 phosphorylation and subsequent ACOD1 transcription. Conversely, dopamine disrupts TLR4-MYD88 interaction via DRD2 without affecting the formation of the LPS-induced TLR4-MD2-CD14 complex. Enhanced ACOD1 expression induces CD274/PD-L1 production independently of itaconate, precipitating inflammation-associated immunosuppression in sepsis. Delayed administration of pramipexole, a dopamine agonist, mitigates lethality in bacterial sepsis mouse models. Conversely, the dopamine antagonist aripiprazole exacerbates sepsis mortality. Dysregulation of the dopamine-ACOD1 axis correlates with sepsis severity in patients, indicating a potential therapeutic target for modulating this neuroimmune pathway.