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.