MOTS-c Promotes Glycolysis via AMPK–HIF-1α–PFKFB3 Pathway to Ameliorate Cardiopulmonary Bypass–induced Lung Injury

Cardiopulmonary bypass (CPB) is essential during cardiac surgery but frequently leads to lung ischemia-reperfusion injury (LIRI), a significant contributor to postoperative complications. We investigated the protective effects of mitochondrial open reading frame of the 12S ribosomal RNA type C (MOTS-c), a mitochondrial-derived peptide, against LIRI-induced acute lung injury (ALI), emphasizing glycolytic reprogramming and ferroptosis in pulmonary microvascular endothelial cells. We hypothesized that MOTS-c exerts its protective effects by regulating glycolysis and suppressing ferroptosis via metabolic signaling pathways. We conducted a prospective, controlled trial involving 107 patients undergoing CPB, evaluating plasma concentrations of MOTS-c and inflammatory markers. MOTS-c concentrations were significantly reduced in patients with ALI. <i>In vivo</i> and <i>in vitro</i> experiments demonstrated that MOTS-c pretreatment alleviated LIRI by enhancing glycolytic flux, reducing oxidative stress, and suppressing ferroptosis in pulmonary microvascular endothelial cells. In particular, MOTS-c reinstated the expression of 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase 3 (PFKFB3), an essential glycolytic enzyme, thus preserving cellular energy homeostasis and diminishing lipid peroxidation. The findings further emphasize the involvement of the AMPK (AMP-activated protein kinase)-hypoxia inducible factor-1α (HIF-1α) signaling pathway in the protective benefits facilitated by MOTS-c. MOTS-c elevated phosphorylated AMPKα and HIF-1α expression, indicating a vital function for these pathways in enhancing glycolysis and antioxidant defenses. Genetic and pharmacological inhibition of PFKFB3 abrogated the protective effects of MOTS-c, thereby confirming the essential role of PFKFB3-mediated glycolysis in alleviating LIRI. Our research indicates that MOTS-c could serve as a potential therapeutic agent for the prevention or treatment of LIRI-induced ALI by enhancing glycolysis, suppressing ferroptosis, and activating the AMPK-HIF-1α pathway. Future study should explore the clinical application of MOTS-c, potentially improving outcomes for patients undergoing high-risk cardiac operations.