Thiazolidinone CFTR inhibitor identified by high-throughput screening blocks cholera toxin-induced intestinal fluid...

Area of Science:

• Pharmacology and Physiology
• Gastroenterology
• Genetic Diseases

Background:

• Secretory diarrhea causes significant infant mortality and adult morbidity globally.
• The cystic fibrosis transmembrane conductance regulator (CFTR) protein is crucial for intestinal and airway fluid secretion; its dysfunction leads to cystic fibrosis.
• Developing effective treatments for secretory diarrheas and cystic fibrosis requires understanding CFTR function and identifying modulators.

Purpose of the Study:

• To screen a large chemical library for compounds that inhibit CFTR-mediated chloride transport.
• To identify and characterize novel inhibitors of the CFTR protein for potential therapeutic applications.
• To evaluate the efficacy of identified inhibitors in reducing intestinal fluid secretion.

Main Methods:

• High-throughput screening of 50,000 diverse compounds for inhibition of cAMP/flavone-stimulated Cl(-) transport in CFTR-expressing epithelial cells.
• Chemical analog screening to identify the most potent inhibitor, CFTR(inh)-172.
• In vitro characterization of CFTR(inh)-172's inhibitory kinetics, specificity, and toxicity in cell culture and mouse models.
• In vivo assessment of CFTR(inh)-172's efficacy in reducing cholera toxin-induced fluid secretion in mice.

Main Results:

• Six inhibitors belonging to the 2-thioxo-4-thiazolidinone class were identified.
• CFTR(inh)-172 emerged as the most potent inhibitor, reversibly inhibiting CFTR with a K(I) of approximately 300 nM.
• CFTR(inh)-172 demonstrated high specificity, not affecting other ion channels or transporters at effective concentrations, and showed no toxicity in cell culture or mouse models.
• A single dose of CFTR(inh)-172 significantly reduced cholera toxin-induced intestinal fluid secretion in mice by over 90%.

Conclusions:

• The 2-thioxo-4-thiazolidinone class of compounds, particularly CFTR(inh)-172, represents a promising avenue for therapeutic development.
• CFTR inhibitors like CFTR(inh)-172 hold potential for treating secretory diarrheas, such as cholera, by reducing excessive intestinal fluid loss.
• These findings may facilitate the development of large-animal models for cystic fibrosis research and offer new therapeutic strategies for CFTR-related disorders.