Skeletal muscle regeneration depends on muscle stem cells (MuSC), whose ability to self-renew and differentiate is essential for maintaining muscle homeostasis. In Duchenne muscular dystrophy (DMD), progressive muscle degeneration is accompanied by impaired regenerative capacity, suggesting a critical dysfunction of MuSC. While mitochondrial alterations and Ca²⁺ dysregulation are well established in dystrophic myofibers, their role in regulating MuSC fate remains poorly understood.
We hypothesize that mitochondrial dysfunction, driven by Ca²⁺ imbalance and aberrant opening of the mitochondrial permeability transition pore (mPTP), represents a cell-autonomous defect in MuSC that disrupts their fate decisions and contributes to regenerative failure in DMD.
To address this, we will isolate Pax7-positive MuSC from human muscle biopsies and mdx5cv mice and characterize mitochondrial bioenergetics, dynamics, mPTP activity, and Ca²⁺ homeostasis. We will determine how these alterations affect MuSC self-renewal and differentiation and test whether pharmacological inhibition of mPTP restores normal MuSC function. Finally, we will apply single-cell RNA sequencing to define the molecular programs associated with MuSC dysfunction and validate key pathways in vivo using zebrafish reporter lines.
This project will establish a mechanistic framework linking mitochondrial dysfunction to MuSC impairment in DMD. By shifting the focus from muscle degeneration to defective regeneration, this study will provide new insights into disease pathogenesis and identify potential targets for future therapeutic strategies.