title: Src family kinases and Syk are required for neutrophil extracellular trap formation in response to β-glucan particles.
abstract: We report that particles of β-glucan, one of the surface components of yeasts, are powerful inducers of neutrophil extracellular trap (NET) formation in human neutrophils. β-Glucan triggered a prolonged phosphorylation of Src family kinases and Syk that were suppressed by the Src family inhibitor 4-amino-5-(4-chlorophenyl)-7-(t-butyl)pyrazolo[3, 4-d] pyrimidine (PP2) and a novel Syk inhibitor, PRT-060318, respectively. PP2 and PRT-060318 also inhibited β-glucan-induced NET formation and reactive oxygen species (ROS) generation, suggesting that both responses are triggered by a Src/Syk-regulated signaling pathway. Given that the NADPH oxidase inhibitor diphenyleneiodonium chloride (DPI) markedly inhibited NET formation, our findings suggest that ROS are required for the full-blown formation of NETs in response to β-glucan particles. Contrary to β-glucan, ROS generation triggered by phorbol myristate acetate (PMA) was unaffected by PP2 and PRT-060318, but these compounds, as well as DPI, suppressed Src/Syk phosphorylation triggered by PMA. Whereas PP2 had no effect on PMA-induced NET formation, PRT-060318 had a significant, albeit partial, inhibitory effect, thus suggesting that ROS induce NET formation in part via activation of Syk. These findings were substantiated by the evidence that neutrophils from mice with the conditional deletion of Syk were defective in formation of NETs in response to β-glucan.
authors.affiliation: Section of General Pathology, Department of Pathology and Diagnostics, University of Verona, Verona, Italy.
authors.forename: Sara
authors.initials: S
authors.lastname: Nanì
authors.forename: Laura
authors.initials: L
authors.lastname: Fumagalli
authors.forename: Uma
authors.initials: U
authors.lastname: Sinha
authors.forename: Lynn
authors.initials: L
authors.lastname: Kamen
authors.forename: Patrizia
authors.initials: P
authors.lastname: Scapini
authors.forename: Giorgio
authors.initials: G
authors.lastname: Berton
mesh_terms: D000818:Animals; D002273:Carcinogens / Q000494:pharmacology; D003514:Cyclohexylamines / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects / Q000235:genetics / Q000276:immunology; D065206:Extracellular Traps / Q000235:genetics / Q000276:immunology*; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000276:immunology*; D051379:Mice; D018345:Mice, Knockout; D009504:Neutrophils / Q000276:immunology*; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000276:immunology*; D011743:Pyrimidines / Q000494:pharmacology; D017382:Reactive Oxygen Species / Q000276:immunology; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics / Q000276:immunology*; D000072377:Syk Kinase; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D019061:src-Family Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000276:immunology*
chemical_list: C569036:2-(2-aminocyclohexylamino)-4-(m-tolylamino)pyrimidine-5-carboxamide; C412373:AG 1879; D002273:Carcinogens; D003514:Cyclohexylamines; D047908:Intracellular Signaling Peptides and Proteins; D011743:Pyrimidines; D017382:Reactive Oxygen Species; D011505:Protein-Tyrosine Kinases; C000606896:SYK protein, human; D000072377:Syk Kinase; C000606897:Syk protein, mouse; D019061:src-Family Kinases; D013755:Tetradecanoylphorbol Acetate