Abstract
Background: Myocardial ischemia/reperfusion (MI/R) injury remains a major challenge in cardiovascular therapeutics, with pathogenesis closely associated with reactive oxygen species (ROS) accumulation and ferroptosis. While sphingosine-1-phosphate receptors (S1PRs) activation demonstrates cardioprotective potential against MI/R injury, its mechanistic relationship with redox homeostasis and ferroptotic pathways requires elucidation. Methods: Using hypoxia/reoxygenation (H/R)-treated cardiomyocytes, we investigated S1P-mediated regulation of Slc7a11, Gpx4, and MnSOD transcription through pharmacological inhibition of the S1PRs/Src/STAT3 signaling pathway. Mechanistic insights into S1PRs/Src/STAT3-mediated transcriptional control were obtained through integrated bioinformatics, dual-luciferase reporter assays, chromatin immunoprecipitation, and molecular profiling (qRT-PCR/ Western blotting). In a MI/R mouse model, the therapeutic effects of S1P and Fingolimod were determined using echocardiography, TTC staining, fluorescent probes, and TEM, with mechanisms validated by Western blotting and qRT-PCR. Results: In vitro studies revealed that S1PRs activation (via S1P or Fingolimod) promoted STAT3 phosphorylation and nuclear translocation through Src signaling, thereby enhancing transcriptional upregulation of Slc7a11, Gpx4, and MnSOD. This signaling cascade attenuated H/R-induced ROS generation, mitochondrial damage, and ferroptosis markers, with S1PR1 demonstrating predominant cytoprotection. Chromatin studies confirmed p-STAT3 binding to antioxidant/ferroptosis-related gene promoters. In vivo findings mirrored cellular observations, showing S1PRs agonism significantly improved cardiac function, reduced infarct size, and suppressed myocardial lipid peroxidation compared with untreated controls. Conclusions: Our findings establish that S1PRs signaling confers cardioprotection against MI/R injury through STAT3 phosphorylation-mediated transcriptional activation of antioxidant defense systems and ferroptosis suppression. This mechanistic insight positions S1PRs modulation as a promising therapeutic strategy for ischemic cardiomyopathy.