Additive Potentiation of R334W-CFTR Function by Novel Small Molecules.

Area of Science:

• Molecular Biology
• Pharmacology
• Genetics

Background:

• The R334W mutation is a rare cause of cystic fibrosis (CF), leading to reduced CFTR channel function with residual activity.
• Current therapies for CFTR mutations focus on enhancing protein function, but specific treatments for R334W are lacking.
• CFTR potentiators are drugs that increase chloride secretion by targeting the CFTR protein at the cell membrane.

Purpose of the Study:

• To identify novel small molecules that can potentiate the function of the R334W-CFTR mutation.
• To validate the efficacy of identified compounds using electrophysiological assays and in relevant cellular and organoid models.
• To explore the potential additive effects of novel compounds in combination with existing CFTR modulators.

Main Methods:

• Generation of a novel cystic fibrosis bronchial epithelial (CFBE) cell line expressing R334W-CFTR for compound screening.
• Functional primary screening of a compound library to identify R334W-CFTR potentiators.
• Electrophysiological measurements, in silico ADME analysis, dose-response studies, and validation in intestinal organoids.

Main Results:

• Four compounds (LSO-24, LSO-25, LSO-38, LSO-77) demonstrated activity in enhancing R334W-CFTR-dependent chloride secretion.
• In silico analysis suggested oral bioavailability for the identified compounds, though they exhibited suboptimal efficacy and potency.
• Combinations of LSO compounds with VX-770 significantly enhanced R334W-CFTR function in cell lines and intestinal organoids.

Conclusions:

• The identified LSO compounds potentiate R334W-CFTR function through a mechanism distinct from VX-770.
• These novel molecules represent a promising starting point for developing improved CFTR potentiators for the R334W mutation.
• Further development of these compounds could lead to new therapeutic strategies for patients with this rare CFTR defect.