biostudies-literatureWu XNational Institute of Arthritis and Musculoskeletal and Skin DiseasesChina Scholarship CouncilNational Institute on Alcohol Abuse and AlcoholismNIDDK NIH HHSNational Institute of Diabetes and Digestive and Kidney DiseasesNIAAA NIH HHSNIAMS NIH HHSNational Institute of General Medical SciencesNIH HHSNIGMS NIH HHS902-919https://www.ebi.ac.uk/biostudies/studies/S-EPMC9741663biostudies-literatureUnknown77(3)<h4>Background and aims</h4>Mixed lineage kinase domain-like pseudokinase (MLKL), a key terminal effector of necroptosis, also plays a role in intracellular vesicle trafficking that is critical for regulating liver inflammation and injury in alcohol-associated liver disease (ALD). Although receptor interacting protein kinase 3 (Rip3)-/- mice are completely protected from ethanol-induced liver injury, Mlkl-/- mice are only partially protected. Therefore, we hypothesized that cell-specific functions of MLKL may contribute to ethanol-induced injury.<h4>Approach and results</h4>Bone marrow transplants between Mlkl-/- mice and littermates were conducted to distinguish the role of myeloid versus nonmyeloid Mlkl in the Gao-binge model of ALD. Ethanol-induced hepatic injury, steatosis, and inflammation were exacerbated in Mlkl-/- →wild-type (WT) mice, whereas Mlkl deficiency in nonmyeloid cells (WT→ Mlkl-/- ) had no effect on Gao-binge ethanol-induced injury. Importantly, Mlkl deficiency in myeloid cells exacerbated ethanol-mediated bacterial burden and accumulation of immune cells in livers. Mechanistically, challenging macrophages with lipopolysaccharide (LPS) induced signal transducer and activator of transcription 1-mediated expression and phosphorylation of MLKL, as well as translocation and oligomerization of MLKL to intracellular compartments, including phagosomes and lysosomes but not plasma membrane. Importantly, pharmacological or genetic inhibition of MLKL suppressed the phagocytic capability of primary mouse Kupffer cells (KCs) at baseline and in response to LPS with/without ethanol as well as peripheral monocytes isolated from both healthy controls and patients with alcohol-associated hepatitis. Further, in vivo studies revealed that KCs of Mlkl-/- mice phagocytosed fewer bioparticles than KCs of WT mice.<h4>Conclusion</h4>Together, these data indicate that myeloid MLKL restricts ethanol-induced liver inflammation and injury by regulating hepatic immune cell homeostasis and macrophage phagocytosis.Hepatology (Baltimore, Md.)Macrophage-derived MLKL in alcohol-associated liver disease: Regulation of phagocytosis.PMC9741663K01 AA029474R24 AA025017R21 AA028117P50 AA024333R01 AA027456P30 DK097948R21 AR071046S10 OD018205P50 AA024337R00 AA029146R01 GM119174U01 AA026938R00 AA028048K99 AA030627U01 AA021890R01 AA023722K99 AA029146F32 AA027950K99 AA028048K08 AA028794L30 AA027913R01 DK060596File:201806280215R01 DK113196Wu JMcCullough AJKim ARotroff DMFan XMcMullen MRDay LZWelch NJacobs JMMiyata TPathak VDasarathy JAllende DSNagy LEHardesty JEDasarathy SWu XfalseMacrophage-derived MLKL in alcohol-associated liver disease: Regulation of phagocytosis.<h4>Background and aims</h4>Mixed lineage kinase domain-like pseudokinase (MLKL), a key terminal effector of necroptosis, also plays a role in intracellular vesicle trafficking that is critical for regulating liver inflammation and injury in alcohol-associated liver disease (ALD). Although receptor interacting protein kinase 3 (Rip3)-/- mice are completely protected from ethanol-induced liver injury, Mlkl-/- mice are only partially protected. Therefore, we hypothesized that cell-specific functions of MLKL may contribute to ethanol-induced injury.<h4>Approach and results</h4>Bone marrow transplants between Mlkl-/- mice and littermates were conducted to distinguish the role of myeloid versus nonmyeloid Mlkl in the Gao-binge model of ALD. Ethanol-induced hepatic injury, steatosis, and inflammation were exacerbated in Mlkl-/- →wild-type (WT) mice, whereas Mlkl deficiency in nonmyeloid cells (WT→ Mlkl-/- ) had no effect on Gao-binge ethanol-induced injury. Importantly, Mlkl deficiency in myeloid cells exacerbated ethanol-mediated bacterial burden and accumulation of immune cells in livers. Mechanistically, challenging macrophages with lipopolysaccharide (LPS) induced signal transducer and activator of transcription 1-mediated expression and phosphorylation of MLKL, as well as translocation and oligomerization of MLKL to intracellular compartments, including phagosomes and lysosomes but not plasma membrane. Importantly, pharmacological or genetic inhibition of MLKL suppressed the phagocytic capability of primary mouse Kupffer cells (KCs) at baseline and in response to LPS with/without ethanol as well as peripheral monocytes isolated from both healthy controls and patients with alcohol-associated hepatitis. Further, in vivo studies revealed that KCs of Mlkl-/- mice phagocytosed fewer bioparticles than KCs of WT mice.<h4>Conclusion</h4>Together, these data indicate that myeloid MLKL restricts ethanol-induced liver inflammation and injury by regulating hepatic immune cell homeostasis and macrophage phagocytosis.2023-01-01T00:00:00Z2023 Mar2026-06-27T03:22:08.848Z2026-06-27T03:17:50.742ZS-EPMC97416633568961310.1002/hep.32612