title: Wolbachia endosymbionts induce neutrophil extracellular trap formation in human onchocerciasis.
abstract: The endosymbiotic bacteria, Wolbachia, induce neutrophilic responses to the human helminth pathogen Onchocerca volvulus. The formation of Neutrophil Extracellular Traps (NETs), has been implicated in anti-microbial defence, but has not been identified in human helminth infection. Here, we demonstrate NETs formation in human onchocerciasis. Extracellular NETs and neutrophils were visualised around O. volvulus in nodules excised from untreated patients but not in nodules from patients treated with the anti-Wolbachia drug, doxycycline. Whole Wolbachia or microspheres coated with a synthetic Wolbachia lipopeptide (WoLP) of the major nematode Wolbachia TLR2/6 ligand, peptidoglycan associated lipoprotein, induced NETosis in human neutrophils in vitro. TLR6 dependency of Wolbachia and WoLP NETosis was demonstrated using purified neutrophils from TLR6 deficient mice. Thus, we demonstrate for the first time that NETosis occurs during natural human helminth infection and demonstrate a mechanism of NETosis induction via Wolbachia endobacteria and direct ligation of Wolbachia lipoprotein by neutrophil TLR2/6.
authors.affiliation: Department of Parasitology, Liverpool School of Tropical Medicine, Pembroke Place L3 5QA, Liverpool, UK.
authors.forename: Francesca
authors.initials: F
authors.lastname: Tamarozzi
authors.affiliation: Department of Parasitology, Liverpool School of Tropical Medicine, Pembroke Place L3 5QA, Liverpool, UK.
authors.forename: Joseph D
authors.initials: JD
authors.lastname: Turner
authors.affiliation: Department of Parasitology, Liverpool School of Tropical Medicine, Pembroke Place L3 5QA, Liverpool, UK.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Pionnier
authors.affiliation: Department of Women's and Children's Health, Alder Hey NHS Foundation Trust, Eaton Road L12 2AP, Liverpool, UK.
authors.forename: Angela
authors.initials: A
authors.lastname: Midgley
authors.affiliation: Department of Parasitology, Liverpool School of Tropical Medicine, Pembroke Place L3 5QA, Liverpool, UK.
authors.forename: Ana F
authors.initials: AF
authors.lastname: Guimaraes
authors.affiliation: Department of Parasitology, Liverpool School of Tropical Medicine, Pembroke Place L3 5QA, Liverpool, UK.
authors.forename: Kelly L
authors.initials: KL
authors.lastname: Johnston
authors.affiliation: Institute of Integrative Biology, University of Liverpool, Crown Street L69 7ZB, Liverpool, UK.
authors.forename: Steven W
authors.initials: SW
authors.lastname: Edwards
authors.affiliation: Department of Parasitology, Liverpool School of Tropical Medicine, Pembroke Place L3 5QA, Liverpool, UK.
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Taylor
mesh_terms: D000818:Animals; D055252:Cell-Derived Microparticles / Q000378:metabolism; D004318:Doxycycline / Q000494:pharmacology / Q000627:therapeutic use; D065206:Extracellular Traps / Q000187:drug effects / Q000378:metabolism*; D005260:Female; D005455:Fluorescent Antibody Technique; D006801:Humans; D055666:Lipopeptides / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D008863:Microspheres; D020556:Neutrophil Infiltration / Q000187:drug effects; D009504:Neutrophils / Q000187:drug effects / Q000378:metabolism*; D009855:Onchocerciasis / Q000188:drug therapy / Q000382:microbiology* / Q000473:pathology; D013559:Symbiosis / Q000187:drug effects; D051216:Toll-Like Receptor 6 / Q000378:metabolism; D020577:Wolbachia / Q000187:drug effects / Q000502:physiology*
chemical_list: D055666:Lipopeptides; D051216:Toll-Like Receptor 6; D004318:Doxycycline