title: Eimeria bovis-triggered neutrophil extracellular trap formation is CD11b-, ERK 1/2-, p38 MAP kinase- and SOCE-dependent.
abstract: Eimeria bovis is an important coccidian parasite that causes high economic losses in the cattle industry. We recently showed that polymorphonuclear neutrophils (PMN) react upon E. bovis sporozoite exposure by neutrophil extracellular trap (NET) formation. We focused here on the molecular mechanisms that are involved in this process. The sporozoite encounter led to an enhanced surface expression of neutrophil CD11b suggesting a potential role of this receptor in E. bovis-mediated NETosis. Antibody-mediated blockage of CD11b confirmed this assumption and led to a significantly decreased sporozoite-triggered NET. In addition, E. bovis-induced NETosis was found to be Ca(2+)-dependent since the inhibition of store-operated calcium entry (SOCE) significantly diminished NET. Furthermore, NADPH oxidase, neutrophil elastase (NE) and myeloperoxidase (MPO) were confirmed as key molecules in sporozoite-triggered NETosis, as inhibition thereof blocked parasite-triggered NET. PMN degranulation analyses revealed a significant release of matrix metalloprotease-9 containing granules upon sporozoite exposure. We further show a significantly enhanced phosphorylation of ERK1/2 and p38 MAPK in sporozoite-exposed PMN indicating a key role of this signaling pathway in E. bovis-mediated NETosis. Accordingly, ERK 1/2 and p38 MAPK inhibition led to a significant decrease in NET formation. Finally, we demonstrate that sporozoite-induced NETosis is neither a stage-, species-, nor host-specific process.
authors.affiliation: Institute of Parasitology, Justus Liebig University Giessen, Schubertstraße 81, 35392, Giessen, Germany. Tamara.Munoz-Caro@vetmed.uni-giessen.de.
authors.forename: Tamara
authors.initials: T
authors.lastname: Muñoz-Caro
authors.affiliation: Laboratory of Inflammation Pharmacology, Institute of Pharmacology and Morphophysiology, Faculty of Veterinary Science, Austral University of Chile, Valdivia, 5110566, Chile. jmenahuertas@ymail.com.|Department of Biology, University of Nariño, Pasto, 520002, Colombia. jmenahuertas@ymail.com.
authors.forename: Sandra Jaqueline
authors.initials: SJ
authors.lastname: Mena Huertas
authors.affiliation: Laboratory of Inflammation Pharmacology, Institute of Pharmacology and Morphophysiology, Faculty of Veterinary Science, Austral University of Chile, Valdivia, 5110566, Chile. ivanconejeros@gmail.com.
authors.forename: Ivan
authors.initials: I
authors.lastname: Conejeros
authors.affiliation: Laboratory of Inflammation Pharmacology, Institute of Pharmacology and Morphophysiology, Faculty of Veterinary Science, Austral University of Chile, Valdivia, 5110566, Chile. pabloalarcon.u@gmail.com.
authors.forename: Pablo
authors.initials: P
authors.lastname: Alarcón
authors.affiliation: Laboratory of Inflammation Pharmacology, Institute of Pharmacology and Morphophysiology, Faculty of Veterinary Science, Austral University of Chile, Valdivia, 5110566, Chile. mahidalgo@uach.cl.
authors.forename: María A
authors.initials: MA
authors.lastname: Hidalgo
authors.affiliation: Laboratory of Inflammation Pharmacology, Institute of Pharmacology and Morphophysiology, Faculty of Veterinary Science, Austral University of Chile, Valdivia, 5110566, Chile. rburgos1@uach.cl.
authors.forename: Rafael A
authors.initials: RA
authors.lastname: Burgos
authors.affiliation: Institute of Parasitology, Justus Liebig University Giessen, Schubertstraße 81, 35392, Giessen, Germany. Carlos.R.Hermosilla@vetmed.uni-giessen.de.
authors.forename: Carlos
authors.initials: C
authors.lastname: Hermosilla
authors.affiliation: Institute of Parasitology, Justus Liebig University Giessen, Schubertstraße 81, 35392, Giessen, Germany. Anja.Taubert@vetmed.uni-giessen.de.
authors.forename: Anja
authors.initials: A
authors.lastname: Taubert
mesh_terms: D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000276:immunology* / Q000469:parasitology*; D003048:Coccidiosis / Q000276:immunology / Q000469:parasitology / Q000662:veterinary*; D004539:Eimeria / Q000276:immunology* / Q000648:ultrastructure; D065206:Extracellular Traps / Q000276:immunology; D007113:Immunity, Innate; D008855:Microscopy, Electron, Scanning / Q000662:veterinary; D008856:Microscopy, Fluorescence / Q000662:veterinary; D009504:Neutrophils / Q000276:immunology; D034101:Sporozoites / Q000276:immunology / Q000648:ultrastructure