scholarly journals Integrity and Stability of PTC Bearing CFTR mRNA and Relevance to Future Modulator Therapies in Cystic Fibrosis

Genes ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1810
Author(s):  
Luka A. Clarke ◽  
Vanessa C. C. Luz ◽  
Szymon Targowski ◽  
Sofia S. Ramalho ◽  
Carlos M. Farinha ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Premature Termination Codon ◽  
Transmembrane Conductance Regulator ◽  
Transmembrane Conductance ◽  
Nonsense Mediated Decay ◽  
Steady State Levels ◽  
Quality Control Mechanism ◽  
Cystic Fibrosis Transmembrane ◽  
Mediated Reduction ◽  
Made In

Major advances have recently been made in the development and application of CFTR (cystic fibrosis transmembrane conductance regulator) mutation class-specific modulator therapies, but to date, there are no approved modulators for Class I mutations, i.e., those introducing a premature termination codon (PTC) into the CFTR mRNA. Such mutations induce nonsense-mediated decay (NMD), a cellular quality control mechanism that reduces the quantity of PTC bearing mRNAs, presumably to avoid translation of potentially deleterious truncated CFTR proteins. The NMD-mediated reduction of PTC-CFTR mRNA molecules reduces the efficacy of one of the most promising approaches to treatment of such mutations, namely, PTC readthrough therapy, using molecules that induce the incorporation of near-cognate amino acids at the PTC codon, thereby enabling translation of a full-length protein. In this study, we measure the effect of three different PTC mutations on the abundance, integrity, and stability of respective CFTR mRNAs, using CFTR specific RT-qPCR-based assays. Altogether, our data suggest that optimized rescue of PTC mutations has to take into account (1) the different steady-state levels of the CFTR mRNA associated with each specific PTC mutation; (2) differences in abundance between the 3′ and 5′ regions of CFTR mRNA, even following PTC readthrough or NMD inhibition; and (3) variable effects on CFTR mRNA stability for each specific PTC mutation.

scholarly journals High-Throughput Screening for Readthrough Modulators of CFTR PTC Mutations

2017 ◽  
Vol 22 (3) ◽  
pp. 315-324 ◽  
Author(s):  
Feng Liang ◽  
Haibo Shang ◽  
Nikole J. Jordan ◽  
Eric Wong ◽  
Dayna Mercadante ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
High Throughput Screening ◽  
Premature Termination Codon ◽  
Surface Expression ◽  
Hereditary Disease ◽  
Transmembrane Conductance Regulator ◽  
Transmembrane Conductance ◽  
Gene Coding ◽  
Cystic Fibrosis Transmembrane ◽  
Personalized Medicines

Cystic fibrosis (CF) is a hereditary disease caused by mutations in the gene coding for the cystic fibrosis transmembrane conductance regulator (CFTR). A large number of nearly 2000 reported mutations, including the premature termination codon (PTC) mutations, urgently require new and personalized medicines. We have developed cell-based assays for readthrough modulators of CFTR PTC mutations (or nonsense mutation suppressors), based on the trafficking and surface expression of CFTR. Approximately 85,000 compounds have been screened for two PTC mutations (Y122X and W1282X). The hit rates at the threshold of 50% greater than vehicle response are 2% and 1.4% for CFTR Y122X and CFTR W1282X, respectively. The overlap of the two hit sets at this stringent hit threshold is relatively small. Only ~28% of the hits from the W1282X screen were also hits in the Y122X screen. The overlap increases to ~50% if compounds are included that in the second screen achieve only a less stringent hit criterion, that is, horseradish peroxidase (HRP) activity greater than three standard deviations above the mean of the vehicle. Our data suggest that personalization may not need to address individual genotypes, but that patients with different CFTR PTC mutations could benefit from the same medicines.

PRO–CF–MED, Clinical Proof of concept for a RNA–targeting Oligonucleotide for a Cystic fibrosis–F508del MEDication, Horizon2020

Impact ◽  
2018 ◽  
Vol 2018 (3) ◽  
pp. 52-54
Author(s):  
Nicolas Lamontagne
Keyword(s):  
Cystic Fibrosis ◽  
Transmembrane Conductance Regulator ◽  
Transmembrane Conductance ◽  
Rna Targeting ◽  
Threatening Condition ◽  
Life Threatening ◽  
Cftr Protein ◽  
Disease Modifying ◽  
Cystic Fibrosis Transmembrane ◽  
Specific Challenge

Cystic fibrosis (CF) is a progressive life–shortening disease caused by a mutation in the cystic fibrosis transmembrane conductance regulator (CFTR) gene leading to a dysfunctional CFTR protein. The disease affects over 70,000 patients worldwide and while many mutations are known, the F508del mutation affects 90% of all patients. The absence of CFTR in the plasma membrane leads to a dramatic decrease in chloride efflux, resulting in viscous mucus that causes severe symptoms in vital organs like the lungs and intestines. For CF patients that suffer from the life threatening F508del mutation only palliative treatment exist. PRO–CF–MED addresses the specific challenge of this call by introducing the first disease modifying medication for the treatment of the CF patients with F508del mutation. The PRO–CF–MED project has been designed to assess the potential clinical efficacy of QR–010, an innovative disease modifying oligonucleotide–based treatment for F508del patients. Partners within PRO–CF–MED have generated very promising preclinical evidence for QR–010 which allows for further clinical assessment of QR–010 in clinical trials. PRO–CF–MED will enable the fast translation of QR–010 towards clinical practice and market authorisation. PRO–CF–MED has the potential to transform this life–threatening condition into a manageable one.

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