Fibroblasts-dependent maturation and phenotype exacerbation of dystrophic hiPSC-derived MYOtissues enables muscle strength evaluation for gene therapy screening

Abstract

ABSTRACTDuchenne muscular dystrophy (DMD) is a lethal muscle wasting disease caused by absence of dystrophin, a protein essential to preserve muscle integrity continuously challenged by contractions. Gene therapy utilizing adeno-associated virus (AAV) to deliver truncated forms of dystrophin (µDys) is currently the most promising therapeutic approach. However, the therapeutic outcome in treated patients has not been as successful as anticipated by animal studies, underscoring the need of improved and high-throughput models for accurate and fast prediction of human response. Here, we describe the generation of MYOtissues, a 3D muscle platform based on direct myogenic conversion of human induced pluripotent stem cells (iPSC), whose structural and functional maturation is enhanced by fibroblasts incorporation. MYOtissues derived from DMD-iPSC including DMD fibroblasts, exacerbated pathogenic hallmarks such as fibrosis and muscle force loss. As a proof of concept, we showed that AAV-mediated µDys gene transfer improved muscle resistance and membrane stability in DMD-MYOtissues, highlighting the suitability of our system for gene therapy screening.