In vivo genome editing restores dystrophin expression in Duchenne muscular dystrophy patient muscle fibers [Amplicon-seq]

Duchenne muscular dystrophy (DMD) is the most common fatal genetic disease. Clustered regularly interspaced short palindromic repeat (CRISPR)-mediated gene editing is a promising strategy for permanently curing DMD. In this study we developed a novel strategy for reframing DMD mutations by CRISPR-mediated large-scale excision of exons 46–54. We compared this approach to other DMD rescue strategies using DMD patient-derived primary muscle-derived stem cells (MDSCs) and found that it showed the highest efficiency in terms of restoring of dystrophin protein expression. We also confirmed that CRISPR from Prevotella and Francisella 1(Cpf1)-mediated genome editing could correct DMD mutation with higher specificity than CRISPR-associated protein 9 (Cas9). Furthermore, A patient-derived xenograft (PDX) DMD mouse model was established by transplanting DMD-MDSCs into immunodeficient mice. CRISPR gene editing components were intramuscularly delivered into the mouse model by adeno-associated virus vectors. Dystrophin expression levels were increased by 10%–30% in human DMD muscle fibers. The restored dystrophin in vivo was functional, as demonstrated by the expression of the dystrophin glycoprotein complex member β-dystroglycan. This study provides a sensitive indicator for in vivo efficacy of gene editing and lays the foundation for a clinical trial of DMD treatment with gene editing technology. The targeting efficiency of gRNAs in DMD-MDSCs were detected by high-throughput sequencing the PCR products of edited DMD gene, three negative control (cas9 only, pbs mock, untreated) and one ontarget samples were produced, each sample has two replicates.