Correction of chloride transport and mislocalization of CFTR protein by vardenafil in the gastrointestinal tract of cystic fibrosis mice

PLoS One. 2013 Oct 24;8(10):e77314. doi: 10.1371/journal.pone.0077314. eCollection 2013.

Abstract

Although lung disease is the major cause of mortality in cystic fibrosis (CF), gastrointestinal (GI) manifestations are the first hallmarks in 15-20% of affected newborns presenting with meconium ileus, and remain major causes of morbidity throughout life. We have previously shown that cGMP-dependent phosphodiesterase type 5 (PDE5) inhibitors rescue defective CF Transmembrane conductance Regulator (CFTR)-dependent chloride transport across the mouse CF nasal mucosa. Using F508del-CF mice, we examined the transrectal potential difference 1 hour after intraperitoneal injection of the PDE5 inhibitor vardenafil or saline to assess the amiloride-sensitive sodium transport and the chloride gradient and forskolin-dependent chloride transport across the GI tract. In the same conditions, we performed immunohistostaining studies in distal colon to investigate CFTR expression and localization. F508del-CF mice displayed increased sodium transport and reduced chloride transport compared to their wild-type littermates. Vardenafil, applied at a human therapeutic dose (0.14 mg/kg) used to treat erectile dysfunction, increased chloride transport in F508del-CF mice. No effect on sodium transport was detected. In crypt colonocytes of wild-type mice, the immunofluorescence CFTR signal was mostly detected in the apical cell compartment. In F508del-CF mice, a 25% reduced signal was observed, located mostly in the subapical region. Vardenafil increased the peak of intensity of the fluorescence CFTR signal in F508del-CF mice and displaced it towards the apical cell compartment. Our findings point out the intestinal mucosa as a valuable tissue to study CFTR transport function and localization and to evaluate efficacy of therapeutic strategies in CF. From our data we conclude that vardenafil mediates potentiation of the CFTR chloride channel and corrects mislocalization of the mutant protein. The study provides compelling support for targeting the cGMP signaling pathway in CF pharmacotherapy.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cations, Monovalent
  • Cell Polarity
  • Chlorides / metabolism
  • Colon / drug effects
  • Colon / metabolism
  • Colon / pathology
  • Cystic Fibrosis / drug therapy*
  • Cystic Fibrosis / genetics
  • Cystic Fibrosis / metabolism
  • Cystic Fibrosis / pathology
  • Cystic Fibrosis Transmembrane Conductance Regulator / agonists
  • Cystic Fibrosis Transmembrane Conductance Regulator / genetics
  • Cystic Fibrosis Transmembrane Conductance Regulator / metabolism*
  • Epithelial Cells / drug effects*
  • Epithelial Cells / metabolism
  • Epithelial Cells / pathology
  • Gene Expression
  • Humans
  • Imidazoles / pharmacology*
  • Intestinal Mucosa / drug effects*
  • Intestinal Mucosa / metabolism
  • Intestinal Mucosa / pathology
  • Ion Transport / drug effects
  • Male
  • Membrane Potentials / drug effects
  • Mice
  • Mice, Inbred CFTR
  • Phosphodiesterase 5 Inhibitors / pharmacology*
  • Piperazines / pharmacology*
  • Sodium / metabolism
  • Sulfones / pharmacology
  • Triazines / pharmacology
  • Vardenafil Dihydrochloride

Substances

  • Cations, Monovalent
  • Chlorides
  • Imidazoles
  • Phosphodiesterase 5 Inhibitors
  • Piperazines
  • Sulfones
  • Triazines
  • Cystic Fibrosis Transmembrane Conductance Regulator
  • Vardenafil Dihydrochloride
  • Sodium

Grant support

Breeding pairs of Cftrtm1EUR (F508del (FVB/129)) mice obtained from the MC Rotterdam, Rotterdam, The Netherlands, with the support of European Economic Community European Coordination Action for Research in Cystic Fibrosis EU FP6 LHHM-CT-2005-018932. The authors thank Vaincre la Mucoviscidose for providing Cftr knockout mice. Vardenafil was a gift from Bayer Pharma (Berlin, Germany). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.