Antisense oligonucleotide therapy for splicing defects in OPA1‐related dominant optic atrophy

Abstract

SummaryMutations in OPA1 are the main cause of dominant optic atrophy (DOA) and have also been implicated in a variety of syndromic neuropathies such as DOAplus or Behr‐like syndrome. We have recently discovered a disease‐causing deep intronic mutation (DIM) in OPA1 that induces a constitutive inclusion of a cryptic exon into OPA1 transcripts. As a potential therapeutic strategy we sought to correct mis‐splicing of the mutant pre‐mRNA by using antisense oligonucleotides targeting the cryptic acceptor splice site and the novel branch point created by the DIM, respectively. Transfection of patient‐derived primary dermal fibroblasts with AONs resulted in splice correction of the mutant pre‐mRNA in a time and concentration dependent manner. Maximal rescue efficacy of up ~55% was obtained with the cryptic acceptor splice site targeting AON. Peak efficacy of splice correction was observed at 4 days after treatment. However, significant effects were still seen 14 days post‐transfection in the proliferating cell culture. Western blot analysis revealed increased amounts of OPA1 protein with maximum amounts at ~3 days post‐treatment. In summary, we provide the first mutation‐specific rescue strategy for OPA1 deficiency using synthetic AONs.