The effect of premature termination codon mutations on CFTR mRNA abundance in human nasal epithelium and intestinal organoids: a basis for read‐through therapies in cystic fibrosis. Issue 3 (10th December 2018)

• Record Type: Journal Article
• Authors: Clarke, Luka A.; Awatade, Nikhil T.; Felício, Veronica M.; Silva, Iris A.; Calucho, Maite; Pereira, Luisa; Azevedo, Pilar; Cavaco, José; Barreto, Celeste; Bertuzzo, Carmen; Gartner, Silvia; Beekman, Jeffrey; Amaral, Margarida D.
• Is Part Of: Human mutation. Volume 40:Issue 3(2019)
• Page Start: 326
• Page End: 334
• Publication Date: 2018-12-10
• Subjects: cystic fibrosis -- NMD -- personalized therapies -- PTC -- read‐through; Human chromosome abnormalities -- Periodicals; Mutation (Biology) -- Periodicals; 616.04205
• DOI: 10.1002/humu.23692
• Languages: English
• ISSNs: 1059-7794

Abstract

Abstract: A major challenge in cystic fibrosis (CF) research is applying mutation‐specific therapy to individual patients with diverse and rare CF transmembrane conductance regulator ( CFTR ) genotypes. Read‐through agents are currently the most promising approach for Class I mutations that introduce premature termination codons (PTCs) into CFTR mRNA. However, variations in degradation of PTC containing transcripts by nonsense mediated decay (NMD) might lower read‐through efficacy. Allele specific quantitative real time (qRT)‐PCR was used to measure variations in CFTR mRNA abundance for several PTC mutations in respiratory cells and intestinal organoids. The majority of PTC mutations were associated with reduced levels of relative mRNA transcript abundance (∼33% and 26% of total CFTR mRNA in respiratory cells and intestinal organoids, respectively, compared to >50% for non‐PTC causing mutations). These levels were generally not affected by PTC mutation type or position, but there could be twofold variations between individuals bearing the same genotype. Most PTC mutations in CFTR are subject to similar levels of NMD, which reduce but do not abolish PTC bearing mRNAs. Measurement of individual NMD levels in intestinal organoids and HNE cells might, therefore, be useful in predicting efficacy of PTC read‐through in the context of personalized CFTR modulator therapy. Abstract : Of >2, 000 mutations causing Cystic Fibrosis (CF) a significant proportion leads to premature termination codons (PTCs) and mRNA degradation. Here, we quantified PTC‐mRNAs for several mutations using allele‐specific PCR in patient‐derived materials (respiratory cells and intestinal organoids). We found that PTC‐bearing CFTR mRNA is reduced to ∼30% of total in both cell types, albeit with 2‐fold variations among individuals bearing the same genotype. Such data might be useful for predicting PTC read‐through efficacy in the context of personalized CF therapy.