title: RIPK3 promotes cell death and NLRP3 inflammasome activation in the absence of MLKL.
abstract: RIPK3 and its substrate MLKL are essential for necroptosis, a lytic cell death proposed to cause inflammation via the release of intracellular molecules. Whether and how RIPK3 might drive inflammation in a manner independent of MLKL and cell lysis remains unclear. Here we show that following LPS treatment, or LPS-induced necroptosis, the TLR adaptor protein TRIF and inhibitor of apoptosis proteins (IAPs: X-linked IAP, cellular IAP1 and IAP2) regulate RIPK3 and MLKL ubiquitylation. Hence, when IAPs are absent, LPS triggers RIPK3 to activate caspase-8, promoting apoptosis and NLRP3-caspase-1 activation, independent of RIPK3 kinase activity and MLKL. In contrast, in the absence of both IAPs and caspase-8, RIPK3 kinase activity and MLKL are essential for TLR-induced NLRP3 activation. Consistent with in vitro experiments, interleukin-1 (IL-1)-dependent autoantibody-mediated arthritis is exacerbated in mice lacking IAPs, and is reduced by deletion of RIPK3, but not MLKL. Therefore RIPK3 can promote NLRP3 inflammasome and IL-1β inflammatory responses independent of MLKL and necroptotic cell death.
authors.affiliation: 1] Inflammation Division, The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, Victoria 3052, Australia [2] Department of Medical Biology, the University of Melbourne, Parkville, Victoria 3050, Australia.
authors.forename: Kate E
authors.initials: KE
authors.lastname: Lawlor
authors.affiliation: 1] Inflammation Division, The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, Victoria 3052, Australia [2] Department of Medical Biology, the University of Melbourne, Parkville, Victoria 3050, Australia.
authors.forename: Nufail
authors.initials: N
authors.lastname: Khan
authors.affiliation: 1] Inflammation Division, The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, Victoria 3052, Australia [2] Department of Medical Biology, the University of Melbourne, Parkville, Victoria 3050, Australia.
authors.forename: Alison
authors.initials: A
authors.lastname: Mildenhall
authors.affiliation: Department of Clinical Microbiology and Immunology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel.
authors.forename: Motti
authors.initials: M
authors.lastname: Gerlic
authors.affiliation: Division of Hematology/Oncology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA.
authors.forename: Ben A
authors.initials: BA
authors.lastname: Croker
authors.affiliation: Division of Hematology/Oncology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA.
authors.forename: Akshay A
authors.initials: AA
authors.lastname: D'Cruz
authors.affiliation: 1] Inflammation Division, The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, Victoria 3052, Australia [2] Department of Medical Biology, the University of Melbourne, Parkville, Victoria 3050, Australia.
authors.forename: Cathrine
authors.initials: C
authors.lastname: Hall
authors.affiliation: 1] Inflammation Division, The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, Victoria 3052, Australia [2] Department of Medical Biology, the University of Melbourne, Parkville, Victoria 3050, Australia.
authors.forename: Sukhdeep
authors.initials: S
authors.lastname: Kaur Spall
authors.affiliation: 1] Inflammation Division, The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, Victoria 3052, Australia [2] Department of Medical Biology, the University of Melbourne, Parkville, Victoria 3050, Australia.
authors.forename: Holly
authors.initials: H
authors.lastname: Anderton
authors.affiliation: 1] Inflammation Division, The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, Victoria 3052, Australia [2] Department of Medical Biology, the University of Melbourne, Parkville, Victoria 3050, Australia.
authors.forename: Seth L
authors.initials: SL
authors.lastname: Masters
authors.affiliation: 1] Inflammation Division, The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, Victoria 3052, Australia [2] Department of Medical Biology, the University of Melbourne, Parkville, Victoria 3050, Australia.
authors.forename: Maryam
authors.initials: M
authors.lastname: Rashidi
authors.affiliation: 1] Inflammation Division, The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, Victoria 3052, Australia [2] Department of Medical Biology, the University of Melbourne, Parkville, Victoria 3050, Australia.
authors.forename: Ian P
authors.initials: IP
authors.lastname: Wicks
authors.affiliation: 1] Inflammation Division, The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, Victoria 3052, Australia [2] Department of Medical Biology, the University of Melbourne, Parkville, Victoria 3050, Australia.
authors.forename: Warren S
authors.initials: WS
authors.lastname: Alexander
authors.affiliation: TetraLogic Pharmaceuticals Corporation, 343 Phoenixville Pike, Malvern, Pennsylvania 19355, USA.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Mitsuuchi
authors.affiliation: TetraLogic Pharmaceuticals Corporation, 343 Phoenixville Pike, Malvern, Pennsylvania 19355, USA.
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Benetatos
authors.affiliation: TetraLogic Pharmaceuticals Corporation, 343 Phoenixville Pike, Malvern, Pennsylvania 19355, USA.
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Condon
authors.affiliation: Institute of Experimental Immunology, University of Zürich, Zürich 8057, Switzerland.
authors.forename: W Wei-Lynn
authors.initials: WW
authors.lastname: Wong
authors.affiliation: 1] Inflammation Division, The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, Victoria 3052, Australia [2] Department of Medical Biology, the University of Melbourne, Parkville, Victoria 3050, Australia.
authors.forename: John
authors.initials: J
authors.lastname: Silke
authors.affiliation: 1] Inflammation Division, The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, Victoria 3052, Australia [2] Department of Medical Biology, the University of Melbourne, Parkville, Victoria 3050, Australia.
authors.forename: David L
authors.initials: DL
authors.lastname: Vaux
authors.affiliation: 1] Inflammation Division, The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, Victoria 3052, Australia [2] Department of Medical Biology, the University of Melbourne, Parkville, Victoria 3050, Australia.
authors.forename: James E
authors.initials: JE
authors.lastname: Vince
mesh_terms: D000818:Animals; D017209:Apoptosis; D001323:Autoantibodies / Q000737:chemistry; D001854:Bone Marrow Cells / Q000166:cytology*; D002352:Carrier Proteins / Q000378:metabolism*; D053181:Caspase 8 / Q000378:metabolism; D004789:Enzyme Activation; D005260:Female; D058847:Inflammasomes / Q000378:metabolism*; D007249:Inflammation; D051034:Inhibitor of Apoptosis Proteins / Q000378:metabolism; D053583:Interleukin-1beta / Q000378:metabolism; D008070:Lipopolysaccharides / Q000737:chemistry; D008099:Liver / Q000196:embryology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D000071199:NLR Family, Pyrin Domain-Containing 3 Protein; D009336:Necrosis; D011494:Protein Kinases / Q000378:metabolism*; D053422:Receptor-Interacting Protein Serine-Threonine Kinases / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D051636:X-Linked Inhibitor of Apoptosis Protein / Q000378:metabolism
chemical_list: D001323:Autoantibodies; C107521:Birc4 protein, mouse; D002352:Carrier Proteins; D058847:Inflammasomes; D051034:Inhibitor of Apoptosis Proteins; D053583:Interleukin-1beta; D008070:Lipopolysaccharides; D000071199:NLR Family, Pyrin Domain-Containing 3 Protein; C492716:Nlrp3 protein, mouse; D014409:Tumor Necrosis Factor-alpha; D051636:X-Linked Inhibitor of Apoptosis Protein; C570694:MLKL protein, mouse; D011494:Protein Kinases; D053422:Receptor-Interacting Protein Serine-Threonine Kinases; C485615:Ripk3 protein, mouse; C505526:Casp8 protein, mouse; D053181:Caspase 8