Disease exacerbation in 3D MYOtissues derived from Duchenne muscular dystrophy iPSC reveals muscle strength loss and enables therapeutic screening

The yet incurable Duchenne muscular dystrophy (DMD) is caused by the 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 (uDys) is currently the most promising therapeutic approach. However, the therapeutic outcome in treated patients revealed discrepancies with animal studies, underscoring the need for improved and high-throughput models for fast and accurate prediction of human response. Here, we describe the generation of MYOtissues, a 3D muscle platform derived from human induced pluripotent stem cells (iPSC), whose structural and functional maturation is enhanced by fibroblasts incorporation. We employed DMD fibroblasts to model and exacerbate pathogenic hallmarks of DMD iPSC-derived MYOtissues, such as fibrosis and muscle force loss, allowing their use as therapeutic readouts. We showed that AAV-mediated uDys gene transfer in DMD-MYOtissues improved muscle resistance and membrane stability and induced restoration of mechanostability pathways while reducing inflammatory hallmarks. This study highlights the suitability of our bioengineering approach for therapeutic screening in DMD with the potential to expand its applications for personalized medicine.