title: Efficient neutrophil extracellular trap induction requires mobilization of both intracellular and extracellular calcium pools and is modulated by cyclosporine A.
abstract: Excessive or aberrant generation of neutrophil extracellular traps (NETs) has recently become implicated in the underlying aetiology of a number of human pathologies including preeclampsia, systemic lupus erythromatosus, rheumatoid arthritis, auto-antibody induced small vessel vasculitis, coagulopathies such as deep vein thrombosis or pulmonary complications. These results imply that effective pharmacological therapeutic strategies will need to be developed to counter overt NETosis in these and other inflammatory disorders. As calcium flux is implicated in the generation of reactive oxygen species and histone citrullination, two key events in NETosis, we analysed the roles of both extra- and intracellular calcium pools and their modulation by pharmacological agents in the NETotic process in detail. Interleukin-8 (IL-8) was used as a physiological stimulus of NETosis. Our data demonstrate that efficient induction of NETosis requires mobilisation of both extracellular and intracellular calcium pools. Since modulation of the calcineurin pathway by cyclosporine A has been described in neutrophils, we investigated its influence on NETosis. Our data indicate that IL-8 induced NETosis is reduced by ascomycin and cyclosporine A, antagonists of the calcineurin pathway, but not following treatment with rapamycin, which utilizes the mTOR pathway. The action of the G protein coupled receptor phospholipase C pathway appears to be essential for the induction of NETs by IL-8, as NETosis was diminished by treatment with either pertussis toxin, a G-protein inhibitor, the phospholipase C inhibitor, U73122, or staurosporine, an inhibitor of protein kinase C. The data regarding the calcineurin antagonists, ascomycin and cyclosporine A, open the possibility to therapeutically suppress or modulate NETosis. They also provide new insight into the mechanism whereby such immune suppressive drugs render transplant patients susceptible to opportunistic fungal infections.
authors.affiliation: Laboratory for Prenatal Medicine, Department of Biomedicine, University Hospital Basel, Basel, Switzerland.
authors.forename: Anurag Kumar
authors.initials: AK
authors.lastname: Gupta
authors.affiliation: Laboratory for Prenatal Medicine, Department of Biomedicine, University Hospital Basel, Basel, Switzerland; Department of Rheumatology, Cantonal Hospital Aarau, Aarau, Switzerland.
authors.forename: Stavros
authors.initials: S
authors.lastname: Giaglis
authors.affiliation: Department of Rheumatology, Cantonal Hospital Aarau, Aarau, Switzerland.
authors.forename: Paul
authors.initials: P
authors.lastname: Hasler
authors.affiliation: Laboratory for Prenatal Medicine, Department of Biomedicine, University Hospital Basel, Basel, Switzerland.
authors.forename: Sinuhe
authors.initials: S
authors.lastname: Hahn
mesh_terms: D001692:Biological Transport / Q000187:drug effects; D002118:Calcium / Q000378:metabolism*; D016572:Cyclosporine / Q000494:pharmacology*; D065206:Extracellular Traps / Q000187:drug effects* / Q000378:metabolism*; D006801:Humans; D007166:Immunosuppressive Agents / Q000494:pharmacology; D042541:Intracellular Space / Q000187:drug effects* / Q000378:metabolism*; D018375:Neutrophil Activation / Q000187:drug effects; D009504:Neutrophils / Q000166:cytology* / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D043562:Receptors, G-Protein-Coupled / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D016559:Tacrolimus / Q000031:analogs & derivatives / Q000494:pharmacology; D010738:Type C Phospholipases / Q000378:metabolism
chemical_list: D007166:Immunosuppressive Agents; D043562:Receptors, G-Protein-Coupled; D016572:Cyclosporine; C058028:immunomycin; D010738:Type C Phospholipases; D002118:Calcium; D016559:Tacrolimus