Factors influencing readthrough therapy for frequent cystic fibrosis premature termination codons

Area of Science:

• Genetics
• Pharmacology
• Molecular Biology

Background:

• Premature termination codons (PTCs) often cause severe genetic disorders.
• Readthrough therapy using small molecules offers a potential treatment strategy.
• Current readthrough therapy outcomes are variable due to factors like drug-induced readthrough levels, target transcript amounts, and recoded protein activity.

Purpose of the Study:

• To identify recoded cystic fibrosis transmembrane conductance regulator (CFTR) channels resulting from readthrough therapy.
• To investigate enhancing these recoded channels using CFTR modulators.
• To establish a framework for genotype-specific treatment adaptation.

Main Methods:

• Measured drug-induced readthrough of 15 PTCs using a dual reporter system with gentamicin and negamycin.
• Evaluated PTC-associated exon skipping with a minigene system.
• Identified incorporated amino acids via mass spectrometry and measured recoded CFTR channel function.
• Assessed nonfunctional channels with CFTR modulators (ivacaftor-lumacaftor).

Main Results:

• Demonstrated that CFTR modulators significantly increased the activity of recoded CFTR channels.
• Confirmed enhanced channel function in patient-derived cells.
• Provided data on the efficacy of different molecules for specific PTCs.

Conclusions:

• CFTR modulators can enhance the function of recoded channels produced by readthrough therapy.
• This approach offers a personalized treatment strategy for cystic fibrosis based on individual genotypes.
• Identifying optimal drug combinations is key to rescuing CFTR channel function.