Acute liver failure(ALF)is a fatal clinical syndrome with no special drug.Recent evidence shows that modulation of macrophage to inhibit inflammation may be a promising strategy for ALF treatment.In this study we investigated the potential therapeutic effects of melittin,a major peptide component of bee venom both in mice model of ALF and in LPS-stimulated macrophages in vitro,and elucidated the underlying mechanisms.ALF was induced in mice by intraperitoneal injection of D-galactosamine/LPS.Then the mice were treated with melittin(2,4,and 8 mg/kg,ip).We showed that melittin treatment markedly improved mortality,attenuated severe symptoms and signs,and alleviated hepatic inflammation in D-galactosamine/LPS-induced ALF mice with the optimal dose being 4 mg/kg.In addition,melittin within the effective doses did not cause significant in vivo toxicity.In LPS-stimulated RAW264.7 macrophages,melittin(0.7 μM)exerted anti-oxidation and anti-inflammation effects.We showed that LPS stimulation promoted aerobic glycolysis of macrophages through increasing glycolytic rate,upregulated the levels of Warburg effect-related enzymes and metabolites including lactate,LDHA,LDH,and GLUT-1,and activated Akt/mTOR/PKM2/HIF-1α signaling.Melittin treatment suppressed M2 isoform of pyruvate kinase(PKM2),thus disrupted the Warburg effect to alleviate inflammation.Molecular docking analysis confirmed that melittin targeted PKM2.In LPS-stimulated RAW264.7 macrophages,knockdown of PKM2 caused similar anti-inflammation effects as melittin did.In D-galactosamine/LPS-induced ALF mice,melittin treatment markedly decreased the expression levels of PKM2 and HIF-1α in liver.This work demonstrates that melittin inhibits macrophage activation-mediated inflammation via inhibition of aerobic glycolysis by targeting PKM2,which highlights a novel strategy of using melittin for ALF treatment.