Duchenne muscular dystrophy is a severe X-linked genetic disease characterized by progressive skeletal muscle degeneration. Although the absence of dystrophin is well known, the mechanisms leading to muscle fiber death are not fully understood.
One of the key events is intracellular calcium overload, associated with the opening of the mitochondrial permeability transition pore (PTP), which plays a major role in muscle fiber death. Animal models of DMD have highlighted mitochondrial dysfunction linked to impaired calcium homeostasis.
Previous studies in the "sapje" zebrafish model, which faithfully reproduces the DMD phenotype, have observed: i) a marked structural defect in muscle fibers; ii) a reduction in mitochondrial respiratory capacity; and iii) early muscle fiber death.
Furthermore, it has been demonstrated that PTP inhibition, both directly and indirectly (e.g., with TR001 or Alisporivir), can significantly improve the pathological phenotype by restoring both mitochondrial function and muscle structure and function.
The primary objective of the project is to fully reconstruct the mechanism of action by which the compound TR001 is able to regenerate muscle fibers in the absence of dystrophin and to identify new therapeutic targets for the development of innovative combinatorial treatments. To achieve these objectives, both myoblasts derived from DMD patients and the mutant zebrafish model (sapje) will be used. The main experimental strategies will include: i) transcriptomic analysis by RNA-seq to identify genes and pathways modulated by pharmacological treatment with the compound TR001 in sapje zebrafish at three different developmental stages; ii) validation of the results by qRT-PCR on RNA isolated from myoblasts from DMD patients; iii) In vivo imaging of zebrafish reporter lines to monitor the effect of TR001 on specific signaling pathways involved in muscle development, calcium homeostasis, and mitochondrial dynamics.
A better understanding of the molecular mechanisms by which the compound TR001 promotes complete recovery of skeletal muscle structure and function, and the simultaneous identification of biomarkers of therapeutic efficacy, as well as potential new therapeutic targets, will allow us to take a further step toward validating a mitochondrial therapy for DMD.
The ultimate goal is to slow or halt disease progression and improve patients' quality of life through the development of innovative therapies based on novel compounds.