Orai1-STIM1 Regulates Increased Ca²⁺ Mobilization, Leading to Contractile Duchenne Muscular Dystrophy Phenotypes in Patient-Derived Induced Pluripotent Stem Cells.

ABSTRACT: Ca²⁺ overload is one of the factors leading to Duchenne muscular dystrophy (DMD) pathogenesis. However, the molecular targets of dystrophin deficiency-dependent Ca²⁺ overload and the correlation between Ca²⁺ overload and contractile DMD phenotypes in in vitro human models remain largely elusive. In this study, we utilized DMD patient-derived induced pluripotent stem cells (iPSCs) to differentiate myotubes using doxycycline-inducible MyoD overexpression, and searched for a target molecule that mediates dystrophin deficiency-dependent Ca²⁺ overload using commercially available chemicals and siRNAs. We found that several store-operated Ca²⁺ channel (SOC) inhibitors effectively prevented Ca²⁺ overload and identified that STIM1-Orai1 is a molecular target of SOCs. These findings were further confirmed by demonstrating that STIM1-Orai1 inhibitors, CM4620, AnCoA4, and GSK797A, prevented Ca²⁺ overload in dystrophic myotubes. Finally, we evaluated CM4620, AnCoA4, and GSK7975A activities using a previously reported model recapitulating a muscle fatigue-like decline in contractile performance in DMD. All three chemicals ameliorated the decline in contractile performance, indicating that modulating STIM1-Orai1-mediated Ca²⁺ overload is effective in rescuing contractile phenotypes. In conclusion, SOCs are major contributors to dystrophin deficiency-dependent Ca²⁺ overload through STIM1-Orai1 as molecular mediators. Modulating STIM1-Orai1 activity was effective in ameliorating the decline in contractile performance in DMD.

SUBMITTER: Uchimura T 

PROVIDER: S-EPMC8615222 | biostudies-literature |

REPOSITORIES: biostudies-literature