WB original data (Efficient exon skipping by base editor-mediated abrogation of exonic splicing enhancers)

Duchenne muscular dystrophy (DMD) is a severe genetic disease caused by the loss of the dystrophin protein. Exon skipping is a promising strategy to treat DMD by restoring truncated dystrophin. Here, we demonstrate that base editors (e.g., Targeted AID-mediated mutagenesis (TAM)) are able to efficiently induce exon skipping by disrupting functional redundant exonic splicing enhancers (ESEs). By developing an unbiased and high-throughput screening to interrogate exonic sequences, we successfully identify novel ESEs in DMD exons 51 and 53. TAM-CBE induces near-complete skipping of the respective exons by targeting these ESEs in patients’ iPSCs-derived cardiomyocytes. Combined with strategies to disrupt splice sites, we identify suitable sgRNAs with TAM-CBE to efficiently skip most DMD hotspot exons without substantial double-stranded breaks. Our study thus expands the repertoire of potential targets for CBE-mediated exon skipping in treating DMD and other RNA mis-splicing diseases.