title: Cyanide levels found in infected cystic fibrosis sputum inhibit airway ciliary function.
abstract: We have previously reported cyanide at concentrations of up to 150 μM in the sputum of cystic fibrosis patients infected with Pseudomonas aeruginosa and a negative correlation with lung function. Our aim was to investigate possible mechanisms for this association, focusing on the effect of pathophysiologically relevant cyanide levels on human respiratory cell function. Ciliary beat frequency measurements were performed on nasal brushings and nasal air-liquid interface (ALI) cultures obtained from healthy volunteers and cystic fibrosis patients. Potassium cyanide decreased ciliary beat frequency in healthy nasal brushings (n = 6) after 60 min (150 μM: 47% fall, p<0.0012; 75 μM: 32% fall, p<0.0001). Samples from cystic fibrosis patients (n = 3) showed similar results (150 μM: 55% fall, p = 0.001). Ciliary beat frequency inhibition was not due to loss of cell viability and was reversible. The inhibitory mechanism was independent of ATP levels. KCN also significantly inhibited ciliary beat frequency in ALI cultures, albeit to a lesser extent. Ciliary beat frequency measurements on ALI cultures treated with culture supernatants from P. aeruginosa mutants defective in virulence factor production implicated cyanide as a key component inhibiting the ciliary beat frequency. If cyanide production similarly impairs mucocilliary clearance in vivo, it could explain the link with increased disease severity observed in cystic fibrosis patients with detectable cyanide in their airway.
authors.affiliation: Dept of Life Sciences, Imperial College, London, UK.
authors.forename: Chandrika
authors.initials: C
authors.lastname: Nair
authors.affiliation: Dept of Paediatric Respiratory Medicine, Royal Brompton Hospital, London, UK.
authors.forename: Amelia
authors.initials: A
authors.lastname: Shoemark
authors.affiliation: Dept of Gene Therapy, Imperial College, London, UK.
authors.forename: Mario
authors.initials: M
authors.lastname: Chan
authors.affiliation: Dept of Paediatric Respiratory Medicine, Royal Brompton Hospital, London, UK.
authors.forename: Sarah
authors.initials: S
authors.lastname: Ollosson
authors.affiliation: Dept of Paediatric Respiratory Medicine, Royal Brompton Hospital, London, UK.
authors.forename: Mellissa
authors.initials: M
authors.lastname: Dixon
authors.affiliation: Dept of Paediatric Respiratory Medicine, Royal Brompton Hospital, London, UK.
authors.forename: Claire
authors.initials: C
authors.lastname: Hogg
authors.affiliation: Dept of Gene Therapy, Imperial College, London, UK.
authors.forename: Eric W F W
authors.initials: EW
authors.lastname: Alton
authors.affiliation: Dept of Gene Therapy, Imperial College, London, UK Joint senior authors.
authors.forename: Jane C
authors.initials: JC
authors.lastname: Davies
authors.affiliation: Dept of Life Sciences, Imperial College, London, UK Joint senior authors h.d.williams@imperial.ac.uk.
authors.forename: Huw D
authors.initials: HD
authors.lastname: Williams
mesh_terms: D000255:Adenosine Triphosphate / Q000737:chemistry; D002470:Cell Survival; D002478:Cells, Cultured / Q000187:drug effects; D002923:Cilia / Q000378:metabolism*; D003486:Cyanides / Q000737:chemistry*; D003550:Cystic Fibrosis / Q000378:metabolism* / Q000382:microbiology; D064368:Healthy Volunteers; D006801:Humans; D009093:Mucus / Q000502:physiology; D009297:Nasal Mucosa / Q000378:metabolism* / Q000382:microbiology; D011190:Potassium Cyanide / Q000737:chemistry; D011379:Prognosis; D011552:Pseudomonas Infections / Q000503:physiopathology; D011550:Pseudomonas aeruginosa; D012129:Respiratory Function Tests; D012137:Respiratory System / Q000503:physiopathology; D013183:Sputum / Q000378:metabolism*
chemical_list: D003486:Cyanides; D000255:Adenosine Triphosphate; D011190:Potassium Cyanide