title: Nontypeable Haemophilus influenzae induces sustained lung oxidative stress and protease expression.
abstract: Nontypeable Haemophilus influenzae (NTHi) is a prevalent bacterium found in a variety of chronic respiratory diseases. The role of this bacterium in the pathogenesis of lung inflammation is not well defined. In this study we examined the effect of NTHi on two important lung inflammatory processes 1), oxidative stress and 2), protease expression. Bronchoalveolar macrophages were obtained from 121 human subjects, blood neutrophils from 15 subjects, and human-lung fibroblast and epithelial cell lines from 16 subjects. Cells were stimulated with NTHi to measure the effect on reactive oxygen species (ROS) production and extracellular trap formation. We also measured the production of the oxidant, 3-nitrotyrosine (3-NT) in the lungs of mice infected with this bacterium. NTHi induced widespread production of 3-NT in mouse lungs. This bacterium induced significantly increased ROS production in human fibroblasts, epithelial cells, macrophages and neutrophils; with the highest levels in the phagocytic cells. In human macrophages NTHi caused a sustained, extracellular production of ROS that increased over time. The production of ROS was associated with the formation of macrophage extracellular trap-like structures which co-expressed the protease metalloproteinase-12. The formation of the macrophage extracellular trap-like structures was markedly inhibited by the addition of DNase. In this study we have demonstrated that NTHi induces lung oxidative stress with macrophage extracellular trap formation and associated protease expression. DNase inhibited the formation of extracellular traps.
authors: Monash University Department of Medicine/Monash Medical Centre, Melbourne, Australia; Monash Lung and Sleep, Monash Medical Centre, Melbourne, Australia.
authors: Paul T
authors: PT
authors: King
authors: Monash University Department of Medicine/Monash Medical Centre, Melbourne, Australia; Monash Lung and Sleep, Monash Medical Centre, Melbourne, Australia.
authors: Roleen
authors: R
authors: Sharma
authors: Monash University Department of Medicine/Monash Medical Centre, Melbourne, Australia.
authors: Kim
authors: K
authors: O'Sullivan
authors: Department of Pharmacology, Monash University, Melbourne, Australia.
authors: Stavros
authors: S
authors: Selemidis
authors: Monash University Department of Medicine/Monash Medical Centre, Melbourne, Australia.
authors: Steven
authors: S
authors: Lim
authors: Monash Lung and Sleep, Monash Medical Centre, Melbourne, Australia.
authors: Naghmeh
authors: N
authors: Radhakrishna
authors: Monash Micro Imaging, Monash University, Melbourne, Australia.
authors: Camden
authors: C
authors: Lo
authors: Monash Lung and Sleep, Monash Medical Centre, Melbourne, Australia.
authors: Jyotika
authors: J
authors: Prasad
authors: Monash Micro Imaging, Monash University, Melbourne, Australia.
authors: Judy
authors: J
authors: Callaghan
authors: Monash Lung and Sleep, Monash Medical Centre, Melbourne, Australia.
authors: Peter
authors: P
authors: McLaughlin
authors: Monash Lung and Sleep, Monash Medical Centre, Melbourne, Australia.
authors: Michael
authors: M
authors: Farmer
authors: Monash Lung and Sleep, Monash Medical Centre, Melbourne, Australia.
authors: Daniel
authors: D
authors: Steinfort
authors: Monash Lung and Sleep, Monash Medical Centre, Melbourne, Australia.
authors: Barton
authors: B
authors: Jennings
authors: Clinical Immunology, Monash Medical Centre, Melbourne, Australia.
authors: James
authors: J
authors: Ngui
authors: Department of Pharmacology, Monash University, Melbourne, Australia.
authors: Bradley R S
authors: BR
authors: Broughton
authors: Monash Lung and Sleep, Monash Medical Centre, Melbourne, Australia; Monash Institute of Medical Research, Melbourne, Australia.
authors: Belinda
authors: B
authors: Thomas
authors: School of Biomedical Sciences and Pharmacy, University of Newcastle, Newcastle, Australia.
authors: Ama-Tawiah
authors: AT
authors: Essilfie
authors: Monash University Department of Medicine/Monash Medical Centre, Melbourne, Australia.
authors: Michael
authors: M
authors: Hickey
authors: Monash Lung and Sleep, Monash Medical Centre, Melbourne, Australia.
authors: Peter W
authors: PW
authors: Holmes
authors: School of Biomedical Sciences and Pharmacy, University of Newcastle, Newcastle, Australia.
authors: Philip
authors: P
authors: Hansbro
authors: Monash Lung and Sleep, Monash Medical Centre, Melbourne, Australia; Monash Institute of Medical Research, Melbourne, Australia.
authors: Philip G
authors: PG
authors: Bardin
authors: Monash University Department of Medicine/Monash Medical Centre, Melbourne, Australia.
authors: Stephen R
authors: SR
authors: Holdsworth
mesh_terms: D000818:Animals; D015373:Bacterial Typing Techniques; D018893:Bronchoalveolar Lavage; D016764:Cell Polarity; D003851:Deoxyribonucleases / Q000378:metabolism; D010450:Endopeptidases / Q000378:metabolism*; D005110:Extracellular Space / Q000378:metabolism; D065206:Extracellular Traps / Q000378:metabolism; D005260:Female; D006193:Haemophilus influenzae / Q000502:physiology*; D006801:Humans; D008168:Lung / Q000201:enzymology* / Q000473:pathology*; D008264:Macrophages / Q000378:metabolism; D008297:Male; D008807:Mice, Inbred BALB C; D008875:Middle Aged; D018384:Oxidative Stress; D010586:Phagocytes / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D017382:Reactive Oxygen Species; D003851:Deoxyribonucleases; D010450:Endopeptidases