Kisspeptin-54 attenuates acute lung injury in septic mice through AMPK-mediated suppression of NLRP3 inflammasome.

Sepsis-induced acute lung injury (ALI) remains a leading cause of death in intensive care, yet targeted therapies are lacking. Kisspeptin-54 is a neuropeptide primarily known for reproductive regulation, though its role in sepsis is unexplored. This study investigated whether exogenous kisspeptin-54 protects against septic lung injury and examined the underlying mechanism. In a cecal ligation and puncture (CLP) mouse model, we observed reduced circulating kisspeptin-54 and downregulated pulmonary GPR54 expression during sepsis. Exogenous kisspeptin-54 improved 7-day survival, lowered clinical severity scores, and attenuated lung injury, as shown by reduced peritoneal inflammatory cell infiltration, decreased pulmonary vascular leakage and edema, and lower IL-1β and IL-18 levels. Mechanistically, kisspeptin-54 suppressed NLRP3 inflammasome components (NLRP3, ASC, cleaved caspase-1) in lung tissue while enhancing AMPK phosphorylation. These protective effects were reversed by the AMPK inhibitor compound C. To define individual responding leukocyte populations, convergent biochemical and morphological evaluations demonstrated that Kisspeptin-54 preferentially curbs pulmonary neutrophil accumulation over macrophages. In addition, cell-autonomous validation using the validated murine alveolar macrophage cell line MH-S confirmed that Kisspeptin-54 directly enhances AMPK phosphorylation, reduces NLRP3 expression by 48%, and suppresses cleaved caspase-1 maturation by 52%, thereby curbing supernatant IL-1β release. Baseline toxicity screening confirmed that therapeutic doses of Kisspeptin-54 alone are entirely non-toxic in healthy animals, while Compound C alone does not exacerbate background septic mortality. These findings indicate that kisspeptin-54 alleviates sepsis-induced ALI, and its protective effects are strongly aligned with AMPK-mediated suppression of NLRP3 inflammasome activation.