title: Neutrophil extracellular traps contain mitochondrial as well as nuclear DNA and exhibit inflammatory potential.
abstract: Neutrophils expel extracellular traps (NETs) to entrap and exterminate the invaded micro-organisms. Acute/chronic inflammatory disorders are often observed with aberrantly enhanced NETs formation and high nitric oxide (NO) availability. Recent study from this laboratory demonstrated release of NETs from human neutrophils following treatment with SNP or SNAP. This study is an extension of our previous finding to explore the extracellular bacterial killing, source of DNA in the expelled NETs, their ability to induce proinflammatory cytokines release from platelets/THP-1 cells, and assessment of NO-mediated free radical formation by using a consistent NO donor, DETA-NONOate. NO-mediated NETs exhibited extracellular bacterial killing as determined by colony forming units. NO-mediated NETs formation was due to the activation of NADPH oxidase and myeloperoxidase. NO- or PMA-mediated NETs were positive for both nuclear and mitochondrial DNA as well as proteolytic enzymes. Incubation of NETs with human platelets enhanced the release of IL-1β and IL-8, while with THP-1 cells, release of IL-1β, IL-8, and TNFα was observed. This study demonstrates that NO by augmenting enzymatic free radical generation release NETs to promote extracellular bacterial killing. These NETs were made up of mitochondrial and nuclear DNA and potentiated release of proinflammatory cytokines.
authors.affiliation: Pharmacology Division, CSIR-Central Drug Research Institute, Lucknow 226 001, India.
authors.forename: Ravi S
authors.initials: RS
authors.lastname: Keshari
authors.forename: Anupam
authors.initials: A
authors.lastname: Jyoti
authors.forename: Sachin
authors.initials: S
authors.lastname: Kumar
authors.forename: Megha
authors.initials: M
authors.lastname: Dubey
authors.forename: Anupam
authors.initials: A
authors.lastname: Verma
authors.forename: Bangalore S
authors.initials: BS
authors.lastname: Srinag
authors.forename: Hanumanthappa
authors.initials: H
authors.lastname: Krishnamurthy
authors.forename: Manoj K
authors.initials: MK
authors.lastname: Barthwal
authors.forename: Madhu
authors.initials: M
authors.lastname: Dikshit
mesh_terms: D000328:Adult; D001792:Blood Platelets / Q000378:metabolism; D004247:DNA / Q000378:metabolism*; D004272:DNA, Mitochondrial / Q000378:metabolism*; D005609:Free Radicals; D006801:Humans; D007249:Inflammation / Q000276:immunology*; D053583:Interleukin-1beta / Q000378:metabolism; D016209:Interleukin-8 / Q000378:metabolism; D008928:Mitochondria / Q000235:genetics; D019255:NADPH Oxidases / Q000378:metabolism; D018375:Neutrophil Activation; D009504:Neutrophils / Q000166:cytology* / Q000378:metabolism*; D009569:Nitric Oxide / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism; D009195:Peroxidase / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha
chemical_list: D004272:DNA, Mitochondrial; D005609:Free Radicals; D053583:Interleukin-1beta; D016209:Interleukin-8; D014409:Tumor Necrosis Factor-alpha; D009569:Nitric Oxide; D004247:DNA; D009195:Peroxidase; D019255:NADPH Oxidases