Abstract

Hyperoxia reduces MOTS-c content and impairs cardiac function in mice. • MOTS-c alleviates cardiac injury in hyperoxia-induced mice. • Hyperoxia activates the KEAP1-PGAM5-AIFM1 axis to induce oxeiptosis, and MOTS-c suppresses it. • MOTS-c potentially binds to KEAP1, stabilizes KEAP1-PGAM5, and blocks AIFM1 nuclear translocation. • KEAP1 overexpression abrogated the protective effects of MOTS-c. Aims Hyperoxia-induced oxidative stress is a primary cause of neonatal injury. Neonatal heart shows a particular susceptibility to hyperoxic toxicity, yet mechanisms and effective therapeutic strategies remain limited. Oxeiptosis is a ROS-specific programmed cell death. Mitochondrial-derived peptide MOTS-c possesses well-known anti-oxidative effect. This study investigated the cardio-protective role of MOTS-c in hyperoxia exposed neonatal mice and its mechanism. Main methods Neonatal mice exposed hyperoxia (85% O 2 ) were used to establish the hyperoxic cardiac injury model. Additionally, the rat cardiomyocyte cell line H9C2 were subjected to hyperoxic conditions as an in vitro model. Serum MOTS-c content was measured using enzyme-linked immunosorbent assay. Hematoxylin and eosin staining, Real-time PCR, Western blotting, immunohistochemistry, and immunofluorescence techniques were employed to evaluate the effects of MOTS-c on hyperoxia-induced cardiac insufficiency. Key findings We found that hyperoxia exposure in neonatal mice led to significant cardiac hypertrophy, fibrosis, and dysfunction, concomitant with decreased serum MOTS-c content. Administration of MOTS-c markedly ameliorated these pathological changes and restored cardiac function. In vitro and in vivo experiments revealed that hyperoxia triggers oxidative stress and oxeiptosis via activating KEAP1-PGAM5-AIFM1 axis, and MOTS-c inhibited oxeiptosis. Mechanistically, MOTS-c could potentially interact with KEAP1, thereby maintaining the KEAP1-PGAM5 interaction, and inhibiting the downstream nuclear translocation o