title: Neutrophil extracellular trap formation is elicited in response to cold physical plasma.
abstract: Cold physical plasma is an ionized gas with a multitude of components, including hydrogen peroxide and other reactive oxygen and nitrogen species. Recent studies suggest that exposure of wounds to cold plasma may accelerate healing. Upon wounding, neutrophils are the first line of defense against invading microorganisms but have also been identified to play a role in delayed healing. In this study, we examined how plasma treatment affects the functions of peripheral blood neutrophils. Plasma treatment induced oxidative stress, as assessed by the oxidation of intracellular fluorescent redox probes; reduced metabolic activity; but did not induce early apoptosis. Neutrophil oxidative burst was only modestly affected after plasma treatment, and the killing of Pseudomonas aeruginosa and Staphylococcus aureus was not significantly affected. Intriguingly, we found that plasma induced profound extracellular trap formation. This was inhibited by the presence of catalase during plasma treatment but was not replicated by adding an equivalent concentration of hydrogen peroxide. Plasma-induced neutrophil extracellular trap formation was not dependent on the activity of myeloperoxidase or NADPH oxidase 2 but seemed to involve short-lived molecules. The amount of DNA release and the time course after plasma treatment were similar to that with the common neutrophil extracellular trap inducer PMA. After neutrophil extracellular traps had formed, concentrations of IL-8 were also significantly increased in supernatants of plasma-treated neutrophils. Both neutrophil extracellular traps and IL-8 release may aid antimicrobial activity and spur inflammation at the wound site. Whether this aids or exacerbates wound healing needs to be tested.
authors.affiliation: Leibniz Institute for Plasma Science and Technology, Greifswald, Germany; Institute of Immunology and Transfusion Medicine, Department of Immunology, University of Greifswald, Germany; sander.bekeschus@inp-greifswald.de.
authors.forename: Sander
authors.initials: S
authors.lastname: Bekeschus
authors.affiliation: Centre for Free Radical Research, Department of Pathology, University of Otago, Christchurch, New Zealand; and.
authors.forename: Christine C
authors.initials: CC
authors.lastname: Winterbourn
authors.affiliation: University Medical Center Utrecht, Department of Medical Microbiology, University of Utrecht, The Netherlands.
authors.forename: Julia
authors.initials: J
authors.lastname: Kolata
authors.affiliation: Leibniz Institute for Plasma Science and Technology, Greifswald, Germany.
authors.forename: Kai
authors.initials: K
authors.lastname: Masur
authors.affiliation: Leibniz Institute for Plasma Science and Technology, Greifswald, Germany.
authors.forename: Sybille
authors.initials: S
authors.lastname: Hasse
authors.affiliation: Institute of Immunology and Transfusion Medicine, Department of Immunology, University of Greifswald, Germany.
authors.forename: Barbara M
authors.initials: BM
authors.lastname: Bröker
authors.affiliation: Centre for Free Radical Research, Department of Pathology, University of Otago, Christchurch, New Zealand; and.
authors.forename: Heather A
authors.initials: HA
authors.lastname: Parker
mesh_terms: D002478:Cells, Cultured; D004247:DNA / Q000032:analysis; D065206:Extracellular Traps / Q000187:drug effects*; D005456:Fluorescent Dyes; D006801:Humans; D016209:Interleukin-8 / Q000502:physiology; D019272:Leukocyte Elastase / Q000032:analysis; D009504:Neutrophils / Q000187:drug effects* / Q000201:enzymology / Q000276:immunology; D009569:Nitric Oxide / Q000502:physiology; D010084:Oxidation-Reduction; D010587:Phagocytosis / Q000187:drug effects; D058626:Plasma Gases / Q000276:immunology* / Q000494:pharmacology; D011550:Pseudomonas aeruginosa; D016897:Respiratory Burst / Q000187:drug effects; D013211:Staphylococcus aureus; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014945:Wound Healing / Q000502:physiology
chemical_list: D005456:Fluorescent Dyes; D016209:Interleukin-8; D058626:Plasma Gases; D009569:Nitric Oxide; D004247:DNA; D019272:Leukocyte Elastase; D013755:Tetradecanoylphorbol Acetate
keywords: kINPen; reactive species; wound healing