Partial correction of defective Cl(-) secretion in cystic fibrosis epithelial cells by an analog of squalamine

Am J Physiol Lung Cell Mol Physiol. 2001 Nov;281(5):L1164-72. doi: 10.1152/ajplung.2001.281.5.L1164.

Abstract

Defective cystic fibrosis (CF) transmembrane conductance regulator (CFTR)-mediated Cl(-) transport across the apical membrane of airway epithelial cells is implicated in the pathophysiology of CF lungs. A strategy to compensate for this loss is to augment Cl(-) transport through alternative pathways. We report here that partial correction of this defect could be attained through the incorporation of artificial anion channels into the CF cells. Introduction of GL-172, a synthetic analog of squalamine, into CFT1 cells increased cell membrane halide permeability. Furthermore, when a Cl(-) gradient was generated across polarized monolayers of primary human airway or Fischer rat thyroid cells in an Ussing chamber, addition of GL-172 caused an increase in the equivalent short-circuit current. The magnitude of this change in short-circuit current was ~30% of that attained when CFTR was maximally stimulated with cAMP agonists. Patch-clamp studies showed that addition of GL-172 to CFT1 cells also increased whole cell Cl(-) currents. These currents displayed a linear current-voltage relationship and no time dependence. Additionally, administration of GL-172 to the nasal epithelium of transgenic CF mice induced a hyperpolarization response to perfusion with a low-Cl(-) solution, indicating restoration of Cl(-) secretion. Together, these results demonstrate that in CF airway epithelial cells, administration of GL-172 is capable of partially correcting the defective Cl(-) secretion.

MeSH terms

  • Amiloride / pharmacology
  • Animals
  • Cells, Cultured
  • Chlorides / metabolism*
  • Cholestanols / chemistry
  • Cholestanols / pharmacology*
  • Cystic Fibrosis / metabolism*
  • Cystic Fibrosis Transmembrane Conductance Regulator / metabolism
  • Diuretics / pharmacology
  • Epithelial Cells / drug effects
  • Epithelial Cells / metabolism
  • Humans
  • Ion Transport
  • Ionophores / pharmacology
  • Membrane Potentials
  • Mice
  • Mice, Transgenic
  • Molecular Structure
  • Nasal Mucosa / metabolism
  • Patch-Clamp Techniques
  • Recombinant Proteins / genetics
  • Recombinant Proteins / metabolism
  • Respiratory Mucosa / cytology
  • Respiratory Mucosa / drug effects
  • Respiratory Mucosa / metabolism*

Substances

  • CFTR protein, human
  • Chlorides
  • Cholestanols
  • Diuretics
  • GL-172 cpd
  • Ionophores
  • Recombinant Proteins
  • Cystic Fibrosis Transmembrane Conductance Regulator
  • Amiloride
  • squalamine