Open reading frame correction using splice-switching antisense oligonucleotides for the treatment of cystic fibrosis

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 119; no. 3
• Main Authors: Michaels, Wren E, Pena-Rasgado, Cecilia, Kotaria, Rusudan, Bridges, Robert J, Hastings, Michelle L
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences 18.01.2022
• Subjects: Alleles; Amino acids; Antisense oligonucleotides; Antisense therapy; Base Sequence; Biological Sciences; Bronchi - pathology; Cell Line; Chloride Channels - metabolism; Chloride currents; Codons; Cystic fibrosis; Cystic Fibrosis - genetics; Cystic Fibrosis - pathology; Cystic Fibrosis - therapy; Cystic fibrosis transmembrane conductance regulator; Cystic Fibrosis Transmembrane Conductance Regulator - genetics; Cystic Fibrosis Transmembrane Conductance Regulator - metabolism; Epithelial cells; Epithelial Cells - metabolism; Epithelium; Exons; Exons - genetics; Gene expression; Homozygote; Humans; mRNA turnover; Mutation; Nonsense-mediated mRNA decay; Oligonucleotides; Oligonucleotides, Antisense - therapeutic use; Open Reading Frames - genetics; Patients; Proteins; RNA Splicing - genetics; RNA, Messenger - genetics; RNA, Messenger - metabolism; Switching; nonsense-mediated decay; splicing; human bronchial epithelial cells; cystic fibrosis; antisense oligonucleotides
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.2114886119

gene mutations that result in the introduction of premature termination codons (PTCs) are common in cystic fibrosis (CF). This mutation type causes a severe form of the disease, likely because of low messenger RNA (mRNA) expression as a result of nonsense-mediated mRNA decay, as well as the production of a nonfunctional, truncated CFTR protein. Current therapeutics for CF, which target residual protein function, are less effective in patients with these types of mutations due in part to low CFTR protein levels. Splice-switching antisense oligonucleotides (ASOs), designed to induce skipping of exons in order to restore the mRNA open reading frame, have shown therapeutic promise preclinically and clinically for a number of diseases. We hypothesized that ASO-mediated skipping of CFTR exon 23 would recover CFTR activity associated with terminating mutations in the exon, including p.W1282X, the fifth most common mutation in CF. Here, we show that CFTR lacking the amino acids encoding exon 23 is partially functional and responsive to corrector and modulator drugs currently in clinical use. ASO-induced exon 23 skipping rescued CFTR expression and chloride current in primary human bronchial epithelial cells isolated from a homozygote patient. These results support the use of ASOs in treating CF patients with class I mutations in exon 23 that result in unstable mRNA and truncations of the CFTR protein.