Cystic fibrosis (CF) caused by the mutation of the Cystic Fibrosis Transmembrane conductance Regulator (CFTR) gene resulting in a decreased Cl- secretion and hyperabsorption of Na+ leading to dehydration of the Airway Surface Liquid (ASL) layer. The reduction in ASL height impairs mucocillary clearance favouring chronic lung infection, inflammation and progressive lung destruction. The eicosanoid Lipoxin A4 (LXA4) described as a signal for the resolution of inflammation, is decreased in the lungs of patients with CF (1). We have previously shown that LXA4 stimulates an apical ATP release activating chloride secretion leading to an increase in ASL height in Human Bronchial Epithelial (HBE) and Cystic Fibrosis Bronchial Epithelial (CFBE) cells (2,3). We hypothesize that decreased levels of LXA4 in CF airways could favour the invasion of airway epithelium by P. aeruginosa that chronically infects the lungs of CF patients.Using a gentamicin invasion assay, confocal microscopy, RT-PCR and Western Blotting, we investigated the role of LXA4 on the epithelial integrity of HBE and CFBE when infected with P. aeruginosa. Exposure of P. aeruginsosa decreased the amount of ZO-1 synthetised by airway epithelial cells and induced disruption of tight junctions in non-CF and CF airway epithelial cells. LXA4 prevented a decrease in expression of ZO-1 and tight junction disruption induced by P. aeruginsosa in non-CF and CF airway epithelial cells. Pre-treatment with LXA4 24hrs prior to inoculation with P. aeruginosa, significantly delayed the invasion of HBE and HCFBE cells by P. aeruginosa within the first 4 hours after inoculation, while LXA4 alone did not affect P. aeruginosa growth. In conclusion, we report a novel role for LXA4 preventing tight junction disruption by P. aeruginosa and delaying the invasion of airway epithelial cells by the bacteria, which may lead to a new therapeutic route for CF patients.The authors acknowledge grant support from Health Research Board of Ireland, The National Children Research Centre and the French National Institute of Health (INSERM)
Physiology 2014 (London, UK) (2014) Proc Physiol Soc 31, PCB111
Poster Communications: Lipoxin A4 delays the invasion of cystic fibrosis bronchial epithelial cells by the pathogen Pseudomonas aeruginosa
G. Higgins1,2, B. J. Harvey2, P. McNally1, V. Urbach1,3
1. National Children's Research Centre, Dublin, Ireland. 2. Molecular Medicine, Royal College of Surgeons in Ireland, Dublin, Ireland. 3. FacultÚ de MÚdecine Paris Descartes - Site Necker, INSERM, Paris, France.
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