Related Experiment Video
Updated: Mar 19, 2026
Functional Reconstitution and Channel Activity Measurements of Purified Wildtype and Mutant CFTR Protein
Published on: March 9, 2015
Potentiators exert distinct effects on human, murine, and Xenopus CFTR
Guiying Cui1, Netaly Khazanov2, Brandon B Stauffer1
1Division of Pulmonology, Allergy/Immunology, Cystic Fibrosis, and Sleep, Department of Pediatrics, Emory + Children's Center for Cystic Fibrosis and Airways Disease Research, Emory University School of Medicine and Children's Healthcare of Atlanta, Atlanta, Georgia; and.
Abstract:
VX-770 (Ivacaftor) has been approved for clinical usage in cystic fibrosis patients with several CFTR mutations. Yet the binding site(s) on CFTR for this compound and other small molecule potentiators are unknown. We hypothesize that insight into this question could be gained by comparing the effect of potentiators on CFTR channels from different origins, e.g., human, mouse, and Xenopus (frog). In the present study, we combined this comparative molecular pharmacology approach with that of computer-aided drug discovery to identify and characterize new potentiators of CFTR and to explore possible mechanism of action. Our results demonstrate that 1) VX-770, NPPB, GlyH-101, P1, P2, and P3 all exhibited ortholog-specific behavior in that they potentiated hCFTR, mCFTR, and xCFTR with different efficacies; 2) P1, P2, and P3 potentiated hCFTR in excised macropatches in a manner dependent on the degree of PKA-mediated stimulation; 3) P1 and P2 did not have additive effects, suggesting that these compounds might share binding sites. Also 4) using a pharmacophore modeling approach, we identified three new potentiators (IOWH-032, OSSK-2, and OSSK-3) that have structures similar to GlyH-101 and that also exhibit ortholog-specific potentiation of CFTR. These could potentially serve as lead compounds for development of new drugs for the treatment of cystic fibrosis. The ortholog-specific behavior of these compounds suggest that a comparative pharmacology approach, using cross-ortholog chimeras, may be useful for identification of binding sites on human CFTR.
Insights
Researchers explored how cystic fibrosis transmembrane conductance regulator (CFTR) potentiators work by comparing effects across species. New potentiators were identified, offering potential leads for cystic fibrosis drug development.
Area of Science:
- Molecular Pharmacology
- Drug Discovery
- Biophysics
Background:
- Cystic fibrosis (CF) treatment involves CFTR potentiators like VX-770.
- The precise binding sites of CFTR potentiators remain unidentified.
- Understanding these sites is crucial for developing more effective CF therapies.
Purpose of the Study:
- To identify and characterize novel CFTR potentiators.
- To explore the mechanism of action of existing and new potentiators.
- To investigate the ortholog-specific behavior of CFTR potentiators.
Main Methods:
- Comparative molecular pharmacology using human, mouse, and Xenopus CFTR.
- Computer-aided drug discovery and pharmacophore modeling.
- Excised macropatch electrophysiology to assess channel function.
Main Results:
- Potentiators (VX-770, NPPB, GlyH-101, P1-P3) showed varying efficacies across human (hCFTR), mouse (mCFTR), and Xenopus (xCFTR) orthologs.
- P1, P2, and P3 potentiation of hCFTR was dependent on PKA stimulation.
- P1 and P2 lacked additive effects, suggesting shared binding sites.
- Three new potentiators (IOWH-032, OSSK-2, OSSK-3) with GlyH-101-like structures were identified.
Conclusions:
- CFTR potentiators exhibit ortholog-specific activity, indicating structural differences in CFTR across species.
- New potentiators were discovered, potentially serving as leads for cystic fibrosis drug development.
- Comparative pharmacology with cross-ortholog chimeras may aid in identifying CFTR binding sites.
