Transcutaneous auricular vagus nerve stimulation alleviates chronic heart failure by targeting cathepsin K/p53-mediated ferroptosis

BACKGROUND: Heart failure remains a major global health challenge, with ferroptosis implicated in its pathogenesis. Transcutaneous auricular vagus nerve stimulation (taVNS) has shown therapeutic potential for heart failure, but its regulatory mechanism underlying myocardial ferroptosis remains unclear. METHODS: Isoproterenol-induced chronic heart failure (CHF) rats received taVNS for 2 weeks. Cardiac function was assessed by echocardiography, while myocardial pathology was analyzed using histological staining. Ferroptosis was evaluated via flow cytometry, transmission electron microscopy, and detection of ferroptosis markers. In vitro, Ang II-stimulated H9C2 cells were treated with Ach or subjected to cathepsin K knockdown. RESULTS: The taVNS treatment improved LVEF and reduced LVIDd/LVIDs in CHF rats, accompanied by attenuated hypertrophy and fibrosis as well as decreased NT-proBNP, TNF-α, and IL-6 levels. Additionally, taVNS suppressed ferroptosis in cardiac tissues of CHF rats, as evidenced by reduced ROS and Fe²⁺ levels, decreased iron deposition, and upregulated SLC7A11 and GPX4 expression. However, the mAChR and α7-nAChR antagonists (atropine and MLA) abolished these benefits of taVNS. Moreover, taVNS inhibited cathepsin K/p53 pathway to suppress ferroptosis in CHF rat cardiac tissues, rescuing SLC7A11 and GPX4 expression and reducing ROS and Fe²⁺ levels. Acetylcholine replicated taVNS effects in vitro, reversing Erastin-induced ferroptosis and suppressing cathepsin K/p53 pathway. CONCLUSION: The taVNS treatment modulated cholinergic receptor activation to suppress cathepsin K/p53-mediated ferroptosis, ameliorating cardiac dysfunction in CHF. These findings revealed the specific mechanism by which taVNS exerted cardioprotection via cholinergic receptors, offering a novel therapeutic strategy for CHF.