title: Caspase-8 scaffolding function and MLKL regulate NLRP3 inflammasome activation downstream of TLR3.
abstract: TLR2 promotes NLRP3 inflammasome activation via an early MyD88-IRAK1-dependent pathway that provides a priming signal (signal 1) necessary for activation of the inflammasome by a second potassium-depleting signal (signal 2). Here we show that TLR3 binding to dsRNA promotes post-translational inflammasome activation through intermediate and late TRIF/RIPK1/FADD-dependent pathways. Both pathways require the scaffolding but not the catalytic function of caspase-8 or RIPK1. Only the late pathway requires kinase competent RIPK3 and MLKL function. Mechanistically, FADD/caspase-8 scaffolding function provides a post-translational signal 1 in the intermediate pathway, whereas in the late pathway it helps the oligomerization of RIPK3, which together with MLKL provides both signal 1 and 2 for inflammasome assembly. Cytoplasmic dsRNA activates NLRP3 independent of TRIF, RIPK1, RIPK3 or mitochondrial DRP1, but requires FADD/caspase-8 in wildtype macrophages to remove RIPK3 inhibition. Our study provides a comprehensive analysis of pathways that lead to NLRP3 inflammasome activation in response to dsRNA.
authors.affiliation: Department of Biochemistry and Molecular Biology, Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA.
authors.forename: Seokwon
authors.initials: S
authors.lastname: Kang
authors.affiliation: Department of Biochemistry and Molecular Biology, Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA.
authors.forename: Teresa
authors.initials: T
authors.lastname: Fernandes-Alnemri
authors.affiliation: Department of Biochemistry and Molecular Biology, Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA.
authors.forename: Corey
authors.initials: C
authors.lastname: Rogers
authors.affiliation: Department of Biochemistry and Molecular Biology, Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA.
authors.forename: Lindsey
authors.initials: L
authors.lastname: Mayes
authors.affiliation: Department of Physiology and Cellular Biophysics, Columbia University Medical Center, New York, New York 10032, USA.
authors.forename: Ying
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Deptartment of Immunology, St Jude Children's Research Hospital, Memphis, Tennessee 38105, USA.
authors.forename: Christopher
authors.initials: C
authors.lastname: Dillon
authors.affiliation: Department of Microbiology and Immunology, Emory Vaccine Center, Emory University School of Medicine, Atlanta, Georgia 30322, USA.
authors.forename: Linda
authors.initials: L
authors.lastname: Roback
authors.affiliation: Department of Microbiology and Immunology, Emory Vaccine Center, Emory University School of Medicine, Atlanta, Georgia 30322, USA.
authors.forename: William
authors.initials: W
authors.lastname: Kaiser
authors.affiliation: Department of Immunology, University of Washington, Seattle Washington 98109-8059 USA.
authors.forename: Andrew
authors.initials: A
authors.lastname: Oberst
authors.affiliation: Department of Biomedical Laboratory Sciences, School of Health Sciences, Shinshu University, Matsumoto, Nagano 390-8621, Japan.
authors.forename: Junji
authors.initials: J
authors.lastname: Sagara
authors.affiliation: Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA.
authors.forename: Katherine A
authors.initials: KA
authors.lastname: Fitzgerald
authors.affiliation: Deptartment of Immunology, St Jude Children's Research Hospital, Memphis, Tennessee 38105, USA.
authors.forename: Douglas R
authors.initials: DR
authors.lastname: Green
authors.affiliation: Department of Microbiology and Immunology, Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA.
authors.forename: Jianke
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Department of Microbiology and Immunology, Emory Vaccine Center, Emory University School of Medicine, Atlanta, Georgia 30322, USA.
authors.forename: Edward S
authors.initials: ES
authors.lastname: Mocarski
authors.affiliation: Department of Biochemistry and Molecular Biology, Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA.
authors.forename: Emad S
authors.initials: ES
authors.lastname: Alnemri
mesh_terms: D033942:Adaptor Proteins, Vesicular Transport / Q000235:genetics / Q000378:metabolism; D000818:Animals; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D053181:Caspase 8 / Q000235:genetics / Q000378:metabolism*; D034281:Dynamins / Q000235:genetics / Q000378:metabolism; D053200:Fas-Associated Death Domain Protein / Q000235:genetics / Q000378:metabolism; D008264:Macrophages / Q000378:metabolism*; D051379:Mice; D018345:Mice, Knockout; D008928:Mitochondria / Q000378:metabolism; D053594:Myeloid Differentiation Factor 88 / Q000235:genetics / Q000378:metabolism; D000071199:NLR Family, Pyrin Domain-Containing 3 Protein; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D012330:RNA, Double-Stranded / Q000378:metabolism*; D053422:Receptor-Interacting Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism; D051196:Toll-Like Receptor 3 / Q000378:metabolism*
chemical_list: D033942:Adaptor Proteins, Vesicular Transport; D002352:Carrier Proteins; D053181:Caspase 8; D034281:Dynamins; D053200:Fas-Associated Death Domain Protein; D053594:Myeloid Differentiation Factor 88; D000071199:NLR Family, Pyrin Domain-Containing 3 Protein; D011494:Protein Kinases; D012330:RNA, Double-Stranded; D053422:Receptor-Interacting Protein Serine-Threonine Kinases; D051196:Toll-Like Receptor 3; C505534:Fadd protein, mouse; C507780:Myd88 protein, mouse; C492716:Nlrp3 protein, mouse; C476286:Ticam1 protein, mouse; C519703:TLR3 protein, mouse; C570694:MLKL protein, mouse; C506251:Ripk1 protein, mouse; C485615:Ripk3 protein, mouse; C505526:Casp8 protein, mouse; C486391:Dnm1l protein, mouse