Cell-based assay for high-throughput quantitative screening of CFTR chloride transport agonists

Am J Physiol Cell Physiol. 2001 Nov;281(5):C1734-42. doi: 10.1152/ajpcell.2001.281.5.C1734.


Drug discovery by high-throughput screening is a promising approach to develop new therapies for the most common lethal genetic disease, cystic fibrosis. Because disease-causing mutations of the cystic fibrosis transmembrane conductance regulator (CFTR) protein produce epithelial cells with reduced or absent Cl(-) permeability, the goal of screening is to identify compounds that restore cell Cl(-) transport. We have developed a rapid, quantitative screening procedure for analysis of CFTR-mediated halide transport in cells with the use of a conventional fluorescence plate reader. Doubly transfected cell lines were generated that express wild-type or mutant CFTR together with a yellow fluorescent protein (YFP)-based halide sensor. CFTR function was assayed from the time course of cell fluorescence in response to extracellular addition of 100 mM I(-) followed by forskolin, resulting in decreased YFP fluorescence due to CFTR-mediated I(-) entry. Cell lines were chosen, and conditions were optimized to minimize basal halide transport to maximize assay sensitivity. In cells cultured on 96-well plastic dishes, the assay gave reproducible halide permeabilities from well to well and could reliably detect a 2% activation of CFTR-dependent halide transport produced by low concentrations of forskolin. Applications of the assay are shown, including comparative dose-dependent CFTR activation by genistein, apigenin, 8-cyclopentyl-1,3-dipropylxanthine, IBMX, 8-methoxypsoralen, and milrinone as well as activation of alternative Cl(-) channels. The fluorescence assay and cell lines should facilitate the screening of novel CFTR activators and the characterization of alternative Cl(-) channels and transporters.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Bacterial Proteins
  • Benzoquinones / pharmacology
  • CHO Cells
  • Cell Line
  • Cells, Cultured
  • Chloride Channel Agonists*
  • Colforsin / pharmacology
  • Cricetinae
  • Cystic Fibrosis Transmembrane Conductance Regulator / agonists*
  • Cytological Techniques
  • Drug Evaluation, Preclinical
  • Flavonoids / pharmacology
  • Genistein / pharmacology
  • Hydrogen-Ion Concentration
  • Luminescent Proteins
  • Microscopy, Fluorescence
  • Rats
  • Rats, Inbred F344


  • Bacterial Proteins
  • Benzoquinones
  • Chloride Channel Agonists
  • Flavonoids
  • Luminescent Proteins
  • yellow fluorescent protein, Bacteria
  • Cystic Fibrosis Transmembrane Conductance Regulator
  • Colforsin
  • Genistein