title: Cystic fibrosis sputum DNA has NETosis characteristics and neutrophil extracellular trap release is regulated by macrophage migration-inhibitory factor.
abstract: Neutrophils are the main proinflammatory cell type in chronically infected lungs of cystic fibrosis (CF) patients; however, they fail to effectively clear the colonizing pathogens. Here, we investigated the molecular composition of non-mucoid and mucoid Pseudomonas aeruginosa-induced neutrophil extracellular traps (NETs) in vitro and compared them to the DNA-protein complexes present in the CF sputum. The protein composition of P. aeruginosa-induced NET fragments revealed that irrespective of the inducing stimuli, NET fragments were decorated with a conserved set of proteins. The DNA-protein complexes derived from CF sputum were consistent with NETosis and shared a similar protein signature, suggesting that the majority of the extracellular DNA was NET derived. The ability of polymorphonuclear leukocytes to produce NETs in response to P. aeruginosa was driven by macrophage migration-inhibitory factor (MIF) by promoting mitogen-activated protein kinase. Analysis of 132 CF patient samples revealed that elevated MIF protein levels correlated with poorer lung function. We suggest that targeting MIF by small molecular inhibitors might reduce the presence of extracellular DNA and serve as an adjunct to the use of antimicrobial drugs that could ultimately reduce bacterial fitness in the lungs during the later stages of CF disease.
authors.affiliation: Department of Medicine, Channing Laboratory, Brigham and Women's Hospital, Harvard Medical School, Boston, Mass., USA.
authors.forename: Markryan
authors.initials: M
authors.lastname: Dwyer
authors.forename: Qiang
authors.initials: Q
authors.lastname: Shan
authors.forename: Samantha
authors.initials: S
authors.lastname: D'Ortona
authors.forename: Rie
authors.initials: R
authors.lastname: Maurer
authors.forename: Robert
authors.initials: R
authors.lastname: Mitchell
authors.forename: Hanne
authors.initials: H
authors.lastname: Olesen
authors.forename: Steffen
authors.initials: S
authors.lastname: Thiel
authors.forename: Johannes
authors.initials: J
authors.lastname: Huebner
authors.forename: Mihaela
authors.initials: M
authors.lastname: Gadjeva
mesh_terms: D000818:Animals; D003550:Cystic Fibrosis / Q000276:immunology* / Q000473:pathology; D004247:DNA / Q000276:immunology*; D048049:Extracellular Signal-Regulated MAP Kinases / Q000235:genetics / Q000276:immunology; D065206:Extracellular Traps / Q000276:immunology*; D005260:Female; D006801:Humans; D019746:Intramolecular Oxidoreductases / Q000235:genetics / Q000276:immunology*; D008263:Macrophage Migration-Inhibitory Factors / Q000235:genetics / Q000276:immunology*; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D011550:Pseudomonas aeruginosa / Q000276:immunology*; D013183:Sputum / Q000276:immunology*
chemical_list: D008263:Macrophage Migration-Inhibitory Factors; D004247:DNA; D048049:Extracellular Signal-Regulated MAP Kinases; D019746:Intramolecular Oxidoreductases; C515598:MIF protein, human; C076231:Mif protein, mouse