Chemogenetic Mitochondrial H2O2 Generation Triggers Dose-Dependent Skeletal Muscle Wasting Signatures

Mitochondrial hydrogen peroxide (mtH₂O₂) has long been implicated in skeletal muscle atrophy, yet its direct role in vivo has remained unresolved due to methodological constraints. Here, we aimed to establish a chemogenetic platform for precise, compartment-specific induction of mtH₂O₂ in adult skeletal muscle and to investigate how graded redox stress impacts on muscle proteostasis in vivo. Using mitochondria-targeted D-amino acid oxidase (mtDAAO), we show that prolonged and/or high mtH₂O₂ exposure progressively activates proteolytic and denervation-associated pathways, culminating in myofiber damage and regeneration. Remarkably, even low exposure to mtH₂O₂ is sufficient to acutely suppress protein synthesis and induce disuse-like atrophy, without structural damage or overt oxidative stress. This approach provides a powerful in vivo framework to dissect subcellular redox-controlled signaling in muscle and identifies mtH₂O₂ as a modulator of muscle proteostasis, with therapeutic relevance for muscle-wasting conditions.