Apolipoprotein A1 attenuates epirubicin-induced cardiotoxicity with GPX4-linked ferroptosis-defense modulation.

Anthracycline-induced cardiotoxicity (AIC), in which ferroptosis-related cardiomyocyte injury has been implicated, remains a major challenge in oncology. This study investigates the therapeutic potential of an apolipoprotein A1 (ApoA1) mimetic peptide, L-4 F, in epirubicin-induced cardiotoxicity (EIC) in a rat model. Rats received epirubicin (2.5 mg/kg/week, i.p.) for six weeks to establish the EIC model, with or without concurrent ApoA1 mimetic treatment (L-4 F, 1 mg/kg/day). Cardiac function was assessed by echocardiography. Myocardial tissues underwent single-nucleus RNA sequencing (snRNA-seq), RegDiffusion-based gene regulatory network inference, Western blot, immunohistochemistry, and ELISA. Mechanistic studies used H9C2 cardiomyoblasts and CMEC-H9C2 Transwell co-culture systems under EPI exposure, with ApoA1 treatment, endothelial IL-33 knockdown, and Ferrostatin-1 (Fer-1) rescue. Glutathione peroxidase 4 (GPX4) expression, intracellular iron, lipid peroxidation, and cell viability were assessed. ApoA1 treatment alleviated diastolic dysfunction and weight loss and partially improved global longitudinal strain. snRNA-seq revealed substantial transcriptional remodeling in cardiomyocytes. RegDiffusion analysis identified coordinated reprogramming of transcription factor regulons, including Ppara, Fos, Egr1, and Klf4. ApoA1 treatment was associated with an anti-ferroptotic pattern of ferroptosis-related gene expression, with relatively higher Gpx4 and Slc7a11 expression and lower Tfrc expression, consistent with increased GPX4 protein levels. Intercellular communication analysis suggested enhanced IL-33/ST2-mediated endothelial-cardiomyocyte signaling following ApoA1 treatment. In vitro, ApoA1 restored GPX4 expression and reduced iron accumulation under EPI stress; these effects were potentiated in co-culture conditions and attenuated by endothelial IL-33 knockdown. In the rescue model, ApoA1 and Fer-1 partially restored viability and reduced MDA. ApoA1 alone did not significantly lower C11-BODIPY oxidation, whereas the combination gave the most consistent effect. ApoA1 attenuates EIC and is associated with modulation of GPX4-linked ferroptosis-related responses. This protective effect may involve endothelial-cardiomyocyte crosstalk, with endothelial IL-33 signaling acting as a partial contributor. These findings highlight a potential cardioprotective mechanism.