RIPK3 Inhibition Mitigates Denervated Muscle Atrophy via NOX4-Mediated Mitochondrial Restoration and Inflammation Suppression.

BACKGROUND: Peripheral nerve injury-induced muscle atrophy shares core pathophysiological features with systemic wasting disorders including cachexia and sarcopenia, yet early molecular triggers remain undefined. This study investigates the pathogenic role of receptor-interacting protein kinase 3 (RIPK3) in denervation atrophy. METHODS: Sciatic denervation was induced in rats for initial time-course transcriptomics and in mice for genetic and pharmacological studies. Assessments in wild-type and RIPK3-knockout mice included transcriptomics (RNA-seq, qPCR), muscle morphology (wet weight ratio, cross-sectional area), histological inflammation (H all p < 0.01). STRING analysis predicted NOX4 as a key downstream effector, validated by reduced NOX4 protein (-46.6%, p = 0.0366) and a consequent 52.2% decrease in ROS accumulation (p < 0.001). Consistently, RIPK3 overexpression in C2C12 myotubes elevated NOX4 (p = 0.0046) and atrophy markers, whereas pharmacological inhibition of RIPK3 in mice replicated the protective phenotype, increasing muscle wet weight ratio (p = 0.0277) and suppressing NOX4 (p = 0.0398) and proteolytic markers. CONCLUSIONS: Denervation activates RIPK3 as a master regulator that drives muscle atrophy via NOX4/ROS-induced mitochondrial dysfunction, sustained inflammation and ubiquitin-proteasome activation. Targeting RIPK3 preserves muscle mass and may offer a novel therapeutic strategy for neurogenic muscle atrophy, with possible implications for related wasting disorders.