Trans‐generational epigenetic regulation associated with the amelioration of Duchenne Muscular Dystrophy

Exon skipping is an effective strategy for the treatment of many Duchenne Muscular Dystrophy (DMD) mutations. Natural exon skipping observed in several DMD cases can help in identifying novel therapeutic tools. Here, we show a DMD study case where the lack of a splicing factor (Celf2a), which results in exon skipping and dystrophin rescue, is due to a maternally inherited trans‐generational epigenetic silencing. We found that the study case and his mother express a repressive long non‐coding RNA, DUXAP8, whose presence correlates with silencing of the Celf2a coding region. We also demonstrate that DUXAP8 expression is lost upon cell reprogramming and that, upon induction of iPSCs into myoblasts, Celf2a expression is recovered leading to the loss of exon skipping and loss of dystrophin synthesis. Finally, CRISPR/Cas9 inactivation of the splicing factor Celf2a was proven to ameliorate the pathological state in other DMD backgrounds establishing Celf2a ablation or inactivation as a novel therapeutic approach for the treatment of Duchenne Muscular Dystrophy. Synopsis The study shows that the inhibition of Celf2a splicing factor isoform is able to partially restore dystrophin production in a subgroup of patients affected by Duchenne Muscular Dystrophy (DMD). Moreover, Celf2a expression is epigenetically regulated and this regulation is mediated by a lncRNA. Partial dystrophin restoration in a DMDΔ44 genetic background was achieved by the depletion of the Celf2a splicing factor isoform. Celf2a restoration was obtained by reprogramming patient fibroblasts into iPSCs. Celf2a silencing, in the case study analysed, is due to a transgenerationally inherited epigenetic regulation. Celf2a regulation is mediated by the lncRNA DUXAP8. Graphical Abstract The study shows that the inhibition of Celf2a splicing factor isoform is able to partially restore dystrophin production in a subgroup of patients affected by Duchenne Muscular Dystrophy (DMD). Moreover, Celf2a expression is epigenetically regulated and this regulation is mediated by a lncRNA.