DMD_ORG

Duchenne muscular dystrophy (DMD), the most severe pediatric muscle-wasting genetic disorders, is caused by the absence of dystrophin, which is an essential protein for muscle fiber integrity. In recent years there was significant progress in the therapeutic approach of AAV-based gene therapy for DMD. In animal models for DMD, the restoration by gene therapy of dystrophin expression was associated by significant muscle function improvement and therapeutic benefit. Unfortunately, this is not yet the case in human trials, where the restoration of dystrophin was so far only marginally associated by medical benefit of the treated patients. While the precise reasons for this different are not completely known, it can be assumed that the human pathology is more complex, compared to animal models. Thus, an important lesson is that animal models fail to reproduce some disease aspects, which emphasis the necessity to develop new disease models. The technology of human organoids was rapidly progressed, in recent years, integrating the advantages of a humanized system with that of reduction of animal experimentation. We have recently identified perturbations of lipid metabolism in DMD. Both our published and preliminary data support strongly that lipid perturbations might be a yet underestimated critically important secondary pathology in DMD. Based on this hypothesis we are developing the concept of combined therapy, integrating the restoration of dystrophin expression with the normalization of lipid metabolism. Based on animal experimentation, we then developed a pipeline for the evaluation of combined therapy in the mdx mouse model. The aim of the present proposal is the development of the human organoid, as an alternative model system for the evaluation of the combined therapy in DMD. Preliminary results, which are presented in the proposal, show that DMD organoids recapitulate many features of the mouse model (in vivo) system, and that are suitable for muscle force analysis as therapeutic readouts, supporting the feasibility to use this system as a human in vitro counterpart to animal in vivo preclinical studies translational. Further optimization of this novel model system may integrate the advantages of 1) robustness of the humanized model, 2) reduction of cost, time and animals, and 3) personalized medicine.