title: Sildenafil (Viagra) corrects DeltaF508-CFTR location in nasal epithelial cells from patients with cystic fibrosis.
abstract: BACKGROUND
  Most patients with cystic fibrosis (CF) have a DeltaF508 mutation resulting in abnormal retention of mutant gene protein (DeltaF508-CFTR) within the cell. This study was undertaken to investigate DeltaF508-CFTR trafficking in native cells from patients with CF with the aim of discovering pharmacological agents that can move DeltaF508-CFTR to its correct location in the apical cell membrane.
  
  
  METHODS
  Nasal epithelial cells were obtained by brushing from individuals with CF. CFTR location was determined using immunofluorescence and confocal imaging in untreated cells and cells treated with sildenafil. The effect of sildenafil treatment on CFTR chloride transport function was measured in CF15 cells using an iodide efflux assay.
  
  
  RESULTS
  In most untreated CF cells DeltaF508-CFTR was mislocalised within the cell at a site close to the nucleus. Exposure of cells to sildenafil (2 hours at 37 degrees C) resulted in recruitment of DeltaF508-CFTR to the apical membrane and the appearance of chloride transport activity. Sildenafil also increased DeltaF508-CFTR trafficking in cells from individuals with CF with a single copy DeltaF508 (DeltaF508/4016ins) or with a newly described CF trafficking mutation (R1283M).
  
  
  CONCLUSIONS
  The findings provide proof of principle for sildenafil as a DeltaF508-CFTR trafficking drug and give encouragement for future testing of sildenafil and related PDE5 inhibitors in patients with CF.
authors.affiliation: Department of Medical Biochemistry and Immunology, University of Wales College of Medicine, Heath Park, Cardiff CF14 4XN, UK. dormer@cardiff.ac.uk
authors.forename: R L
authors.initials: RL
authors.lastname: Dormer
authors.forename: C M
authors.initials: CM
authors.lastname: Harris
authors.forename: Z
authors.initials: Z
authors.lastname: Clark
authors.forename: M M C
authors.initials: MM
authors.lastname: Pereira
authors.forename: I J M
authors.initials: IJ
authors.lastname: Doull
authors.forename: C
authors.initials: C
authors.lastname: Norez
authors.forename: F
authors.initials: F
authors.lastname: Becq
authors.forename: M A
authors.initials: MA
authors.lastname: McPherson
mesh_terms: D000293:Adolescent; D000328:Adult; D001692:Biological Transport / Q000187:drug effects / Q000235:genetics; D002648:Child; D002675:Child, Preschool; D002712:Chlorides / Q000378:metabolism; D003550:Cystic Fibrosis / Q000235:genetics / Q000378:metabolism*; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D004847:Epithelial Cells / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D006801:Humans; D007223:Infant; D009154:Mutation / Q000235:genetics; D009666:Nose; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology*; D010879:Piperazines / Q000494:pharmacology*; D011687:Purines; D020545:Respiratory Mucosa; D000068677:Sildenafil Citrate; D013450:Sulfones
chemical_list: C505032:CFTR protein, human; D002712:Chlorides; D010726:Phosphodiesterase Inhibitors; D010879:Piperazines; D011687:Purines; D013450:Sulfones; C093349:cystic fibrosis transmembrane conductance regulator delta F508; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D000068677:Sildenafil Citrate