title: The effect of the decoy molecule PA401 on CXCL8 levels in bronchoalveolar lavage fluid of patients with cystic fibrosis.
abstract: BACKGROUND
  The chemokine interleukin-8 (CXCL8) is a key mediator of inflammation in airways of patients with cystic fibrosis (CF). Glycosaminoglycans (GAGs) possess the ability to influence the chemokine profile of the CF lung by binding CXCL8 and protecting it from proteolytic degradation. CXCL8 is maintained in an active state by this glycan interaction thus increasing infiltration of immune cells such as neutrophils into the lungs. As the CXCL8-based decoy PA401 displays no chemotactic activity, yet demonstrates glycan binding affinity, the aim of this study was to investigate the anti-inflammatory effect of PA401 on CXCL8 levels, and activity, in CF airway samples in vitro.
  
  
  METHODS
  Bronchoalveolar lavage fluid (BALF) was collected from patients with CF homozygous for the ΔF508 mutation (n=13). CXCL8 in CF BALF pre and post exposure to PA401 was quantified by ELISA. Western blot analysis was used to determine PA401 degradation in CF BALF. The ex vivo chemotactic activity of purified neutrophils in response to CF airway secretions was evaluated post exposure to PA401 by use of a Boyden chamber-based motility assay.
  
  
  RESULTS
  Exposure of CF BALF to increasing concentrations of PA401 (50-1000pg/ml) over a time course of 2-12h in vitro, significantly reduced the level of detectable CXCL8 (P<0.05). Interestingly, PA401 engendered release of CXCL8 from GAGs exposing the chemokine susceptible to proteolysis. Subsequently, a loss of PA401 was observed (P<0.05) due to proteolytic degradation by elastase like proteases. A 25% decrease in neutrophil chemotactic efficiency towards CF BALF samples incubated with PA401 was also observed (P<0.05).
  
  
  CONCLUSIONS
  PA401 can disrupt CXCL8:GAG complexes, rendering the chemokine susceptible to proteolytic degradation. Clinical application of a CXCL8 decoy, such as PA401, may serve to decrease the inflammatory burden in the CF lung in vivo.
authors.affiliation: Respiratory Research Division, Royal College of Surgeons in Ireland, ERC Beaumont Hospital, Dublin 9, Ireland.
authors.forename: Oliver J
authors.initials: OJ
authors.lastname: McElvaney
authors.affiliation: Respiratory Research Division, Royal College of Surgeons in Ireland, ERC Beaumont Hospital, Dublin 9, Ireland.
authors.forename: Niamh
authors.initials: N
authors.lastname: O'Reilly
authors.affiliation: Respiratory Research Division, Royal College of Surgeons in Ireland, ERC Beaumont Hospital, Dublin 9, Ireland.
authors.forename: Michelle
authors.initials: M
authors.lastname: White
authors.affiliation: Respiratory Research Division, Royal College of Surgeons in Ireland, ERC Beaumont Hospital, Dublin 9, Ireland.
authors.forename: Noreen
authors.initials: N
authors.lastname: Lacey
authors.affiliation: Respiratory Research Division, Royal College of Surgeons in Ireland, ERC Beaumont Hospital, Dublin 9, Ireland.
authors.forename: Kerstin
authors.initials: K
authors.lastname: Pohl
authors.affiliation: ProtAffin Biotechnologie AG, Impulszentrum Graz-West, Reininghausstraße 13a, 8020 Graz, Austria.
authors.forename: Tanja
authors.initials: T
authors.lastname: Gerlza
authors.affiliation: Respiratory Research Division, Royal College of Surgeons in Ireland, ERC Beaumont Hospital, Dublin 9, Ireland.
authors.forename: David A
authors.initials: DA
authors.lastname: Bergin
authors.affiliation: Respiratory Research Division, Royal College of Surgeons in Ireland, ERC Beaumont Hospital, Dublin 9, Ireland.
authors.forename: Hilary
authors.initials: H
authors.lastname: Kerr
authors.affiliation: Respiratory Research Division, Royal College of Surgeons in Ireland, ERC Beaumont Hospital, Dublin 9, Ireland.
authors.forename: Cormac
authors.initials: C
authors.lastname: McCarthy
authors.affiliation: Respiratory Research Division, Royal College of Surgeons in Ireland, ERC Beaumont Hospital, Dublin 9, Ireland.
authors.forename: M Emmet
authors.initials: ME
authors.lastname: O'Brien
authors.affiliation: ProtAffin Biotechnologie AG, Impulszentrum Graz-West, Reininghausstraße 13a, 8020 Graz, Austria.
authors.forename: Tiziana
authors.initials: T
authors.lastname: Adage
authors.affiliation: ProtAffin Biotechnologie AG, Impulszentrum Graz-West, Reininghausstraße 13a, 8020 Graz, Austria.
authors.forename: Andreas J
authors.initials: AJ
authors.lastname: Kungl
authors.affiliation: Respiratory Research Division, Royal College of Surgeons in Ireland, ERC Beaumont Hospital, Dublin 9, Ireland. Electronic address: emerreeves@rcsi.ie.
authors.forename: Emer P
authors.initials: EP
authors.lastname: Reeves
authors.affiliation: Respiratory Research Division, Royal College of Surgeons in Ireland, ERC Beaumont Hospital, Dublin 9, Ireland.
authors.forename: Noel G
authors.initials: NG
authors.lastname: McElvaney
mesh_terms: D001992:Bronchoalveolar Lavage Fluid; D002633:Chemotaxis / Q000187:drug effects; D003550:Cystic Fibrosis / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay; D006025:Glycosaminoglycans / Q000378:metabolism; D006801:Humans; D016209:Interleukin-8 / Q000378:metabolism*; D009504:Neutrophils / Q000187:drug effects / Q000473:pathology; D059748:Proteolysis / Q000187:drug effects; D011994:Recombinant Proteins / Q000494:pharmacology*; D055815:Young Adult
chemical_list: D006025:Glycosaminoglycans; D016209:Interleukin-8; D011994:Recombinant Proteins
keywords: Antagonist decoy; Bronchoalveolar lavage fluid; Cystic fibrosis; Glycosaminoglycan; Interleukin-8/CXCL8; Neutrophils