Cardiac <i>Slc25a49</i>‐Mediated Energy Reprogramming Governs Doxorubicin‐Induced Cardiomyopathy through the G6P–AP‐1–Sln Axis

Doxorubicin (Dox), a potent antitumor drug, is linked to cardiac toxicity. Few mechanism-based therapies against cardiotoxicity are available. Dysfunction in mitochondrial energy metabolism contributes to Dox-induced cardiomyopathy. It is aimed at exploring the association between specific mechanism of energy reprogramming and Dox-induced cardiomyopathy. Cardiac-specific ablation of Slc25a49 mice are generated by crossing Slc25a49^flox/flox mice with Myh6-Cre mice. Slc25a49^HKO mice or SLC25A49^KD cardiomyocytes is treated with Dox. Echocardiography, histological analysis, transmission electron microscopy, bulk RNA sequencing, cell bioenergetic profiling, metabolomics test, chromatin immunoprecipitation, and dual-luciferase reporter assay are conducted to delineate the phenotype and elucidate the molecular mechanisms. Specific ablation of Slc25a49 in cardiomyocytes leads to exacerbated Dox-induced cardiomyopathy, characterized by compromised mitochondrial respiration enhanced glycolysis and increased glycolytic metabolite glucose-6-phosphate (G6P) levels, subsequently activating the activator protein-1 (AP-1) complex. The stimulation of the G6P-AP-1 axis intensifies myocardial damage via transcriptionally regulating Sarcolipin (Sln) expression. Strikingly, targeting of this axis with the AP-1 inhibitor T-5224 effectively improves survival and enhances cardiac function in Dox-induced cardiomyopathy. This study provides mechanistic insights into energy reprogramming that permits myocardial dysfunction, and thus provides a proof of concept for antienergy reprogramming therapy for Dox-induced cardiomyopathy through directly modulating G6P-AP-1-Sln axis.