Protosappanin a protects DOX-induced myocardial injury and cardiac dysfunction by targeting ACSL4/FTH1 axis-dependent ferroptosis

Background Doxorubicin (DOX) is a breakthrough drug in cancer therapy that mediates irreversible dosedependent cardiotoxicity with poor outcomes.Cardiomyocyte ferroptosis plays a pivotal role in the progression of DOX-induced cardiomyopathy (DIC). Agents that block DOX-induced cardiomyocyte ferroptosis may have clinical utility in the treatment of DIC. Purpose We pursued the potential role of protosappanin A (PrA), an active constituent extract from traditional Chinese hematoxylin, on DOX-induced cardiac dysfunction. Methods We established acute DIC murine models to investigate the role of PrA in DOX-induced cardiotoxicity.In vivo, western blotting was performed to assess the levels of classical proteins associated with the iron death pathway, while Prussian blue staining and DHE staining were utilized to measure iron ion levels and reactive oxygen species respectively. In vitro, DOX-induced H9C2 cells model was established and the level of ferroptosis-related indicators were detected,such as iron, reactive oxygen species (ROS), and lipid peroxides. Proteome microarray, Molecular docking and Cellular thermal shift assay were used to identify the molecular targets (ACSL4 and FTH1) of PrA. Pull-down assay was used to validate the interaction of PrA with ACSL4 and FTH1 proteins in lysates from H9c2 cells, and explored theirs possible mechanism of action. Finally, we investigated the in vivo effect of PrA treatment in mice challenged with a myocardial ischemia-reperfusion mouse model. Results We report for the first time that PrA ameliorates myocardial damage and cardiac dysfunction in a mouse model of DIC. PrA improves DOX-induced ferroptotic phenotypes in cardiomyocytes, as demonstrated by reduced production of iron, reactive oxygen species (ROS), and lipid peroxides, thereby preserving mitochondrial homeostasis. PrA physically combines with the ferroptosis-related protein acyl-CoA synthetase long-chain family member 4 (ACSL4) and ferritin heavy chain 1 (FTH1), thus conferring the following regulatory mechanisms: PrA inhibits ACSL4 phosphorylation and subsequent phospholipid peroxidation; PrA prevents FTH1 autophagic degradation and subsequent ferrous ions (Fe2+) release. Notably, the cardioprotective and antiferroptotic activities of PrA are verified in a myocardial ischemiareperfusion mouse model. Conclusion Our studies indicate for the first time that PrA has a superior protective effect against DOX-induced cardiotoxicity via inhibiting a dual ferroptosis-assistance mechanism of the ACSL4/FTH1-dependent axis. We unveil a novel pharmacological inhibitor that targets ferroptosis, highlighting additional therapeutic options for chemodrug-induced cardiotoxicity and ferroptosis-triggered disorders.