P2X7 Receptor acts as a novel target for ameliorating Sepsis-induced skeletal muscle atrophy in mice model.

Background and objective: Sepsis, a systemic inflammatory syndrome, frequently leads to substantial skeletal muscle loss and dysfunction, severely impairing patient prognosis. The P2X7 receptor is an ATP-gated cation channel implicated in inflammation and cell death. Although its role in the immune system has been extensively studied, its expression profile and pathogenic mechanism in sepsis-induced skeletal muscle atrophy remain unclear. This study aimed to investigate the functional role of the P2X7 receptor in sepsis-associated muscle injury and its potential as a therapeutic target.

Methods: A murine sepsis model was established using cecal ligation and puncture (CLP) surgery. Temporal changes in P2X7 receptor expression in the gastrocnemius (GP) and tibialis anterior (TA) muscles were assessed. Functional studies were performed using P2X7 knockout (P2X7⁻/⁻) mice and the P2X7-specific antagonist A-740003. Skeletal muscle atrophy, inflammatory responses, and activation of the NLRP3 inflammasome signaling pathway were systematically evaluated through Western blotting, qPCR, hematoxylin-eosin staining, muscle fiber cross-sectional area analysis, and measurement of inflammatory cytokines.

Results: In the CLP-induced sepsis model, P2X7 receptor expression in both GP and TA muscles was upregulated in a time-dependent manner. P2X7 gene deletion significantly attenuated body weight loss, muscle mass reduction, and muscle fiber atrophy, restored grip strength, and suppressed the expression of atrophy-related genes (Myostatin, Atrogin-1, and MuRF1). Moreover, it markedly reduced IL-6, IL-18, and IL-1β levels in both skeletal muscle and plasma, indicating an anti-inflammatory effect. P2X7 deficiency also significantly inhibited the expression of NLRP3 inflammasome components, caspase-1, and GSDMD, thereby blocking the pyroptosis signaling pathway. Pharmacological inhibition with A-740003 showed dose-dependent mitigation of muscle atrophy, further supporting the therapeutic potential of targeting P2X7.

Conclusion: The P2X7 receptor contributes to sepsis-induced skeletal muscle atrophy by promoting inflammation and muscle protein degradation through activation of the NLRP3 inflammasome and pyroptosis pathways. Genetic or pharmacological inhibition of P2X7 significantly alleviates muscle damage and functional loss. These findings provide strong experimental evidence supporting P2X7 as a potential therapeutic target for sepsis-associated myopathy.