Pterostilbene Alleviates Doxorubicin-induced cardiotoxicity by Inhibiting Cardiomyocytes Pyroptosis Mediated by the IL-6/STAT3-caspase-3/GSDME Axis and M1 Polarization of Macrophages

Doxorubicin (DOX)-induced cardiotoxicity (DIC) is a major dose-limiting complication of chemotherapy, in which pyroptosis is considered a key pathological mechanism. The natural stilbene compound pterostilbene (PTE) has demonstrated cardioprotective potential, but its role in DOX-induced pyroptosis remains unclear. This study, using both in vitro H9C2 cardiomyocyte and in vivo C57BL/6 mouse models of DIC, confirmed that PTE effectively inhibits DOX-induced cardiomyocyte pyroptosis and alleviates cardiac injury. Mechanistically, DOX activates the IL-6/STAT3 signaling pathway, promoting the nuclear translocation of phosphorylated STAT3 (pSTAT3). CUT&Tag and dual-luciferase reporter assays further revealed that activated STAT3 directly binds to the core promoter regions of the caspase-3 and Gasdermin E (GSDME) genes, thereby upregulating their expression at the transcriptional level and ultimately activating the caspase-3/GSDME-mediated pyroptosis pathway. PTE effectively blocks this pyroptotic execution pathway by inhibiting the activation of the IL-6/STAT3 pathway. Furthermore, this study elucidated a critical interaction between cardiomyocytes and immune cells: GSDME-mediated cardiomyocyte pyroptosis releases various soluble factors, with IL-6 being a key cytokine that drives the polarization of macrophages toward the pro-inflammatory M1 phenotype, thereby amplifying the myocardial inflammatory response. By inhibiting cardiomyocyte pyroptosis, particularly by reducing IL-6 release, PTE effectively interrupts this "cardiomyocyte pyroptosis-M1 macrophage polarization" vicious cycle and restores myocardial homeostasis. In summary, our research elucidates a signaling cascade driving DOX-induced cardiotoxicity: IL-6/STAT3-caspase-3/GSDME. We confirmed that PTE is an effective inhibitor of this pathway, not only directly protecting cardiomyocytes but also suppressing the subsequent pyroptosis-driven inflammatory response, thereby highlighting its significant therapeutic potential in mitigating DIC.