title: Critical role for the NLRP3 inflammasome during acute lung injury.
abstract: The inflammasome is a key factor in innate immunity and senses soluble pathogen and danger-associated molecular patterns as well as biological crystals (urate, cholesterol, etc.), resulting in expression of IL-1β and IL-18. Using a standard model of acute lung injury (ALI) in mice featuring airway instillation of LPS, ALI was dependent on availability of NLRP3 as well as caspase-1, which are known features of the NLRP3 inflammasome. The appearance of IL-1β, a product of NLRP3 inflammasome activation, was detected in bronchoalveolar lavage fluids (BALF) in a macrophage- and neutrophil-dependent manner. Neutrophil-derived extracellular histones appeared in the BALF during ALI and directly activated the NLRP3 inflammasome. Ab-mediated neutralization of histones significantly reduced IL-1β levels in BALF during ALI. Inflammasome activation by extracellular histones in LPS-primed macrophages required NLRP3 and caspase-1 as well as extrusion of K(+), increased intracellular Ca(2+) concentration, and generation of reactive oxygen species. NLRP3 and caspase-1 were also required for full extracellular histone presence during ALI, suggesting a positive feedback mechanism. Extracellular histone and IL-1β levels in BALF were also elevated in C5a-induced and IgG immune complex ALI models, suggesting a common inflammatory mechanism. These data indicate an interaction between extracellular histones and the NLRP3 inflammasome, resulting in ALI. Such findings suggest novel targets for treatment of ALI, for which there is currently no known efficacious drug.
authors.affiliation: Department of Pathology, University of Michigan Medical School, Ann Arbor, MI 48109.
authors.forename: Jamison J
authors.initials: JJ
authors.lastname: Grailer
authors.affiliation: Department of Pathology, University of Michigan Medical School, Ann Arbor, MI 48109.
authors.forename: Bethany A
authors.initials: BA
authors.lastname: Canning
authors.affiliation: Department of Pathology, University of Michigan Medical School, Ann Arbor, MI 48109.
authors.forename: Miriam
authors.initials: M
authors.lastname: Kalbitz
authors.affiliation: Department of Pathology, University of Michigan Medical School, Ann Arbor, MI 48109.
authors.forename: Mikel D
authors.initials: MD
authors.lastname: Haggadone
authors.affiliation: Department of Pathology, University of Michigan Medical School, Ann Arbor, MI 48109.
authors.forename: Rasika M
authors.initials: RM
authors.lastname: Dhond
authors.affiliation: Department of Pathology, University of Michigan Medical School, Ann Arbor, MI 48109.
authors.forename: Anuska V
authors.initials: AV
authors.lastname: Andjelkovic
authors.affiliation: Department of Pathology, University of Michigan Medical School, Ann Arbor, MI 48109.
authors.forename: Firas S
authors.initials: FS
authors.lastname: Zetoune
authors.affiliation: Department of Pathology, University of Michigan Medical School, Ann Arbor, MI 48109 pward@med.umich.edu.
authors.forename: Peter A
authors.initials: PA
authors.lastname: Ward
mesh_terms: D055371:Acute Lung Injury / Q000139:chemically induced / Q000235:genetics / Q000276:immunology* / Q000473:pathology; D000818:Animals; D001992:Bronchoalveolar Lavage Fluid / Q000276:immunology; D002352:Carrier Proteins / Q000235:genetics / Q000276:immunology*; D020170:Caspase 1 / Q000235:genetics / Q000276:immunology; D004195:Disease Models, Animal; D006657:Histones / Q000235:genetics / Q000276:immunology; D058847:Inflammasomes / Q000235:genetics / Q000276:immunology*; D020382:Interleukin-18 / Q000235:genetics / Q000276:immunology; D053583:Interleukin-1beta / Q000235:genetics / Q000276:immunology; D008070:Lipopolysaccharides / Q000494:pharmacology; D016676:Macrophages, Alveolar / Q000276:immunology* / Q000473:pathology; D051379:Mice; D018345:Mice, Knockout; D000071199:NLR Family, Pyrin Domain-Containing 3 Protein; D009504:Neutrophils / Q000276:immunology* / Q000473:pathology
chemical_list: D002352:Carrier Proteins; D006657:Histones; D058847:Inflammasomes; D020382:Interleukin-18; D053583:Interleukin-1beta; D008070:Lipopolysaccharides; D000071199:NLR Family, Pyrin Domain-Containing 3 Protein; C492716:Nlrp3 protein, mouse; D020170:Caspase 1