Discovery of novel potent ΔF 508‐ CFTR correctors that target the nucleotide binding domain

Abstract

The deletion of Phe508 (ΔF508) in the first nucleotide binding domain (NBD1) of CFTR is the most common mutation associated with cystic fibrosis. The ΔF508-CFTR mutant is recognized as improperly folded and targeted for proteasomal degradation. Based on molecular dynamics simulation results, we hypothesized that interaction between ΔF508-NBD1 and housekeeping proteins prevents ΔF508-CFTR delivery to the plasma membrane. Based on this assumption we applied structure-based virtual screening to identify new low-molecular-weight compounds that should bind to ΔF508-NBD1 and act as protein–protein interaction inhibitors. Using different functional assays for CFTR activity, we demonstrated that in silico-selected compounds induced functional expression of ΔF508-CFTR in transfected HeLa cells, human bronchial CF cells in primary culture, and in the nasal epithelium of homozygous ΔF508-CFTR mice. The proposed compounds disrupt keratin8-ΔF508-CFTR interaction in ΔF508-CFTR HeLa cells. Structural analysis of ΔF508-NBD1 in the presence of these compounds suggests their binding to NBD1. We conclude that our strategy leads to the discovery of new compounds that are among the most potent correctors of ΔF508-CFTR trafficking defect known to date.

Searching for Combinations of Small-Molecule Correctors to Restore F508del–Cystic Fibrosis Transmembrane Conductance Regulator Function and Processing

“…Class C3 small molecules are binders to F508del-NBD1 like those recently discovered by Odolczyk and colleagues (Odolczyk et al, 2013). Based on molecular dynamics simulations, these researchers identified by structure-based virtual screening four in silico-selected compounds-NS118208, NS407882, NS130813, and NS73100-and show for the most efficient ones-NS118208 and NS407882-that they bind to F508del-NBD1 and inhibit interactions between F508del-CFTR and the housekeeping protein keratin 8 (Odolczyk et al, 2013). Furthermore, within this class C3, we included RDR1, a substituted phenylhydrazone compound that binds directly to F508del-NBD1 (Sampson et al, 2011).…”

“…Although the precise binding site for VX-809 on CFTR remains unknown, several lines of evidence suggest that it may bind at least to the first transmembrane domain of CFTR (Loo et al, 2013). Class C3 small molecules are binders to F508del-NBD1 like those recently discovered by Odolczyk and colleagues (Odolczyk et al, 2013). Based on molecular dynamics simulations, these researchers identified by structure-based virtual screening four in silico-selected compounds-NS118208, NS407882, NS130813, and NS73100-and show for the most efficient ones-NS118208 and NS407882-that they bind to F508del-NBD1 and inhibit interactions between F508del-CFTR and the housekeeping protein keratin 8 (Odolczyk et al, 2013).…”

An unexpected effect of TNF-α on F508del-CFTR maturation and function

“…The technique for patch-clamp recordings in the whole-cell configuration has been described elsewhere 16,17 . Stably transfected cells were plated in 35-mm glass bottom plates that were mounted on the stage of an inverted microscope.…”

Rattlesnake Phospholipase A2 Increases CFTR-Chloride Channel Current and Corrects ∆ F508CFTR Dysfunction: Impact in Cystic Fibrosis

“…The amplitude of CFTR current induced by CB correction was even larger than that induced by Corr4A 9 showing efficient benefit of the CB-∆F508CFTR interaction. Human hsPLA 2 -IIA, homologous to CB, which did not increase F508CFTR Cl -current but even reduced its activity showed that binding of hsPLA 2 -IIA to ∆F508NBD1 has negative functional consequences on CFTR current.…”

“…6 F508CFTR should constitute a therapeutic target 9 . However, there is still a major need for the development of new selective and high affinity compounds acting as dual modulators.…”