OR01

Duchenne Muscular Dystrophy (DMD) is an X-linked genetic disease caused by mutations in the DMD gene, coding for dystrophin. Its deficiency causes muscle degeneration in young boys, for which no curative treatment exists to date, despite several promising therapeutic approaches. Among them, gene therapy using vectors derived from the adeno-associated virus (AAV) allows the long-term expression of therapeutic transgenes and an almost complete phenotypic rescue in animal models. However, in clinical trials, some patients have developed serious adverse events that were not anticipated in pre-clinical studies. Therefore, new experimental models are needed, with better predictive power for the efficacy and toxicity of AAV vectors.

In this context, we develop a preclinical testing platform for DMD gene therapy using skeletal muscle organoids derived from human induced pluripotent stem cells (hiPSCs). We first generated large batches of myogenic progenitors from DMD and control hiPSCs, that we use to generate contractile skeletal muscle organoids. Then, using a reporter AAV vector, we determined the most efficient vector embedding strategy for successful transduction in organoids, together with the minimal dose and efficient serotypes. Importantly, we observed that transgene expression was maintained over 4 weeks, proving that our preclinical organoid model allows for medium-term monitoring of AAV efficacy in vitro. We will then evaluate the efficacy of a therapeutic AAV-microdystrophin vector in DMD organoids to demonstrate the relevance of in vitro gene therapy in a disease context. In the future, this preclinical testing platform could be used to screen libraries of next generation AAV vectors.