title: A novel mechanism of rapid nuclear neutrophil extracellular trap formation in response to Staphylococcus aureus.
abstract: Neutrophil extracellular traps (NETs) are webs of DNA covered with antimicrobial molecules that constitute a newly described killing mechanism in innate immune defense. Previous publications reported that NETs take up to 3-4 h to form via an oxidant-dependent event that requires lytic death of neutrophils. In this study, we describe neutrophils responding uniquely to Staphylococcus aureus via a novel process of NET formation that did not require neutrophil lysis or even breach of the plasma membrane. The multilobular nucleus rapidly became rounded and condensed. During this process, we observed the separation of the inner and outer nuclear membranes and budding of vesicles, and the separated membranes and vesicles were filled with nuclear DNA. The vesicles were extruded intact into the extracellular space where they ruptured, and the chromatin was released. This entire process occurred via a unique, very rapid (5-60 min), oxidant-independent mechanism. Mitochondrial DNA constituted very little if any of these NETs. They did have a limited amount of proteolytic activity and were able to kill S. aureus. With time, the nuclear envelope ruptured, and DNA filled the cytoplasm presumably for later lytic NET production, but this was distinct from the vesicular release mechanism. Panton-Valentine leukocidin, autolysin, and a lipase were identified in supernatants with NET-inducing activity, but Panton-Valentine leukocidin was the dominant NET inducer. We describe a new mechanism of NET release that is very rapid and contributes to trapping and killing of S. aureus.
authors.affiliation: Snyder Institute of Infection, Immunity and Inflammation, Hiroshima University, Hiroshima, Japan.
authors.forename: Florian H
authors.initials: FH
authors.lastname: Pilsczek
authors.forename: Davide
authors.initials: D
authors.lastname: Salina
authors.forename: Karen K H
authors.initials: KK
authors.lastname: Poon
authors.forename: Candace
authors.initials: C
authors.lastname: Fahey
authors.forename: Bryan G
authors.initials: BG
authors.lastname: Yipp
authors.forename: Christopher D
authors.initials: CD
authors.lastname: Sibley
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Robbins
authors.forename: Francis H Y
authors.initials: FH
authors.lastname: Green
authors.forename: Mike G
authors.initials: MG
authors.lastname: Surette
authors.forename: Motoyuki
authors.initials: M
authors.lastname: Sugai
authors.forename: M Gabriela
authors.initials: MG
authors.lastname: Bowden
authors.forename: Muzaffar
authors.initials: M
authors.lastname: Hussain
authors.forename: Kunyan
authors.initials: K
authors.lastname: Zhang
authors.forename: Paul
authors.initials: P
authors.lastname: Kubes
mesh_terms: D001427:Bacterial Toxins / Q000276:immunology*; D002843:Chromatin / Q000276:immunology*; D003593:Cytoplasm / Q000276:immunology; D004272:DNA, Mitochondrial / Q000276:immunology*; D005098:Exotoxins / Q000276:immunology*; D006801:Humans; D007113:Immunity, Innate / Q000276:immunology*; D007956:Leukocidins / Q000276:immunology*; D009504:Neutrophils / Q000276:immunology*; D010084:Oxidation-Reduction; D013211:Staphylococcus aureus / Q000276:immunology*
chemical_list: D001427:Bacterial Toxins; D002843:Chromatin; D004272:DNA, Mitochondrial; D005098:Exotoxins; D007956:Leukocidins; C078284:Panton-Valentine leukocidin