Cardiac PTN-SIRT1 axis alleviates oxidative stress and promotes mitochondrial energy reprogramming to mitigate doxorubicin-induced cardiotoxicity through AMPK/PGC1α signaling

Doxorubicin (DOX) remains a cornerstone chemotherapeutic agent for malignancies, yet its clinical utility is severely limited by dose-dependent cardiotoxicity, which can lead to progressive left ventricular dysfunction and heart failure. Pleiotrophin (PTN), a heparin-binding growth factor with diverse physiological functions, regulates glucose and lipid metabolism and promotes oxidative energy pathways. However, whether PTN exerts protective effects against DOX-induced cardiotoxicity (DIC) remains unclear. In this study, we establish cellular and animal models of DIC. DOX administration induces pronounced myocardial injury in both models, characterized by impaired ventricular contractility, increased fibrotic remodeling, and reduced cell viability. Concurrently, PTN protein expression is significantly downregulated in cardiomyocytes under DOX treatment. Overexpression of <i>PTN</i> substantially alleviates these pathological changes. <i>In vitro</i>, PTN reduces mitochondrial oxidative stress and apoptosis while restoring energy production and cell viability. <i>In vivo</i>, PTN improves mitochondrial ultrastructure, decreases cardiomyocyte apoptosis, and enhances cardiac function. Mechanistically, PTN directly binds to SIRT1 and activates AMPK phosphorylation at Thr172, triggering a downstream cascade through the AMPK-PGC1α axis that reprograms mitochondrial energy metabolism and attenuates cardiotoxicity. In conclusion, the PTN-SIRT1 axis protects against DIC by reducing oxidative stress and promoting mitochondrial energy homeostasis via the AMPK/PGC1α pathway, highlighting its potential as a novel therapeutic target for preventing chemotherapy-related cardiac injury.