Functional Correction of CFTR Mutations in Human Airway Epithelial Cells using Adenine Base Editors

We investigated the use of adenine base editor (ABE) ribonucleoproteins (RNPs) that convert A-T to G-C base pairs as a therapeutic strategy for three cystic fibrosis disease causing mutations. Using ABE RNPs, we corrected in human airway epithelial cells premature stop codon mutations (R553X and W1282X) and a splice-site mutation (3849+10kb C-T). Following ABE delivery, DNA sequencing was used to quantify the efficiency of editing and to assess the presence of bystander edits or indels. We also evaluated the frequency of off target editing by sequencing the top 10 computationally predicted off target sites for each mutation studied.