Lievre, C. | bioRxiv Science

bioRxiv2026

Engineered muscle tissues with enhanced maturation enable the identification of clinically relevant rAAV capsids

Developing in vitro models that recapitulate both the structure and function of native human tissues is crucial for a better understanding of pathophysiology and for improving the reliability of preclinical studies. Here, we demonstrate that engineered muscle tissues derived from human pluripotent stem cells can serve as an in vitro platform for gene therapy. Recombinant vectors derived from the adeno-associated virus transduce engineered muscle tissues with high efficiency and in a dose-dependent manner, allowing long term assessment of transgene expression in a human cellular context. We next used this model to conduct a comparative analysis of 8 natural AAV capsids and showed that their relative efficiency depends on engineered muscle tissue maturation level. In more mature tissues subjected to uniaxial mechanical stretch, AAV9 performed better, which is reminiscent of its high clinical potential in patients with neuromuscular disorders. Finally, our model also confirmed the higher efficiency of artificial MyoAAV variants specifically developed to have an improved muscle transduction. Altogether, this work demonstrates the potential of human engineered muscle tissues in the preclinical testing of AAV vectors, paving the way for the development of personalized gene therapy platforms.

bioengineering↗

bioRxiv2023

Dystrophin deficiency impairs cell junction formation during embryonic myogenesis

Mutations in the DMD gene lead to Duchenne muscular dystrophy, a severe X-linked neuromuscular disorder that manifests itself as young boys acquire motor functions. DMD is typically diagnosed at 2 to 4 years of age, but the absence of dystrophin negatively impacts muscle structure and function before overt symptoms appear in patients, which poses a serious challenge in the optimization of standards of care. In this report, we investigated the early consequences of dystrophin deficiency during skeletal muscle development. We used single-cell transcriptome profiling to characterize the myogenic trajectory of human pluripotent stem cells and showed that DMD cells bifurcate to an alternative branch when they reach the somite stage. Here, dystrophin deficiency was linked to marked dysregulations of cell junction protein families involved in the cell state transitions characteristic of embryonic somitogenesis. Altogether, this work demonstrates that in vitro, dystrophin deficiency has deleterious effects on cell-cell communication during myogenic development, which should be considered in future therapeutic strategies for DMD.

pathology↗