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Transepithelial fluctuation analysis of chloride secretion
Ashvani K Singh1, Bruce D Schultz, Willy van Driessche
1Vertex Pharmaceuticals Inc., 11010 Torreyana Road, San Diego, CA 92121, USA.
Summary
Transepithelial noise analysis reveals approximately 7000 active cystic fibrosis transmembrane conductance regulator (CFTR) channels per T84 cell. This method quanties CFTR channel properties in intact epithelia, aiding drug discovery.
Area of Science:
- Epithelial physiology
- Ion channel biophysics
Background:
- Transepithelial fluctuation analysis (noise analysis) is a key technique for studying ion channel function in intact epithelial tissues.
- Understanding the properties of ion channels like the cystic fibrosis transmembrane conductance regulator (CFTR) is crucial for epithelial function and disease research.
Purpose of the Study:
- To investigate cystic fibrosis transmembrane conductance regulator (CFTR)-dependent chloride (Cl-) secretion in T84 human colonic epithelia.
- To utilize noise analysis with a specific CFTR blocker (DASU-01) to quantify CFTR channel properties in situ.
Main Methods:
- Employing transepithelial fluctuation analysis (noise analysis) on T84 human colonic epithelial cells.
- Inducing noise by applying DASU-01, a low-affinity open-channel blocker of CFTR.
- Measuring chloride (Cl-) secretion and CFTR channel parameters.
Main Results:
- The apical membrane of maximally stimulated T84 epithelia exhibits high Cl- conductance.
- Approximately 7000 active CFTR channels per cell were estimated.
- The open probability (Po) was approximately 0.4, and the single-channel amplitude (i) was approximately 0.1 pA.
Conclusions:
- Noise analysis effectively quantifies CFTR channel density and properties in intact epithelia.
- The study provides baseline CFTR channel parameters for T84 cells under stimulated conditions.
- This methodology holds promise for evaluating how drugs modulate CFTR function in epithelial models.