[HTML][HTML] Cut and paste: efficient homology-directed repair of a dominant negative KRT14 mutation via CRISPR/Cas9 nickases

T Kocher, P Peking, A Klausegger, EM Murauer… - Molecular Therapy, 2017 - cell.com
T Kocher, P Peking, A Klausegger, EM Murauer, JP Hofbauer, V Wally, T Lettner, S Hainzl…
Molecular Therapy, 2017cell.com
With the ability to induce rapid and efficient repair of disease-causing mutations,
CRISPR/Cas9 technology is ideally suited for gene therapy approaches for recessively and
dominantly inherited monogenic disorders. In this study, we have corrected a causal hotspot
mutation in exon 6 of the keratin 14 gene (KRT14) that results in generalized severe
epidermolysis bullosa simplex (EBS-gen sev), using a double-nicking strategy targeting
intron 7, followed by homology-directed repair (HDR). Co-delivery into EBS keratinocytes of …
With the ability to induce rapid and efficient repair of disease-causing mutations, CRISPR/Cas9 technology is ideally suited for gene therapy approaches for recessively and dominantly inherited monogenic disorders. In this study, we have corrected a causal hotspot mutation in exon 6 of the keratin 14 gene (KRT14) that results in generalized severe epidermolysis bullosa simplex (EBS-gen sev), using a double-nicking strategy targeting intron 7, followed by homology-directed repair (HDR). Co-delivery into EBS keratinocytes of a Cas9 D10A nickase (Cas9n), a predicted single guide RNA pair specific for intron 7, and a minicircle donor vector harboring the homology donor template resulted in a recombination efficiency of >30% and correction of the mutant KRT14 allele. Phenotypic correction of EBS-gen sev keratinocytes was demonstrated by immunofluorescence analysis, revealing the absence of disease-associated K14 aggregates within the cytoplasm. We achieved a promising safety profile for the CRISPR/Cas9 double-nicking approach, with no detectable off-target activity for a set of predicted off-target genes as confirmed by next generation sequencing. In conclusion, we demonstrate a highly efficient and specific gene-editing approach for KRT14, offering a causal treatment option for EBS.
cell.com