Interleukin-6/STAT3-hepcidin signaling amplifies ferroptosis in hypoxia/reoxygenation-injured H9C2 cardiomyoblasts.

BACKGROUND: Inflammatory activation contributes to myocardial ischemia/reperfusion injury, but the mechanisms linking interleukin-6 (IL-6) signaling to ferroptotic cardiomyocyte damage remain incompletely defined. This study investigated whether IL-6 aggravates hypoxia/reoxygenation (H/R)-induced ferroptosis in H9C2 cardiomyoblasts through the STAT3-Hepcidin-FPN1 axis. METHODS: H9C2 cells were subjected to H/R, IL-6 stimulation, ferrostatin-1 (Fer-1) rescue, STAT3 inhibition with Stattic, and hepcidin add-back. Cell viability, lipid reactive oxygen species, intracellular Fe2 + , HAMP mRNA expression, and protein levels of GPX4, xCT, p-STAT3/STAT3, and FPN1 were assessed. RESULTS: H/R reduced cell viability, increased lipid peroxidation and Fe2 + accumulation, and downregulated GPX4 and xCT, confirming a ferroptotic phenotype. Fer-1 partially restored viability and suppressed lipid ROS but did not fully normalize Fe2 + levels. IL-6 further aggravated H/R-induced injury, enhanced STAT3 phosphorylation, and increased HAMP expression. Stattic inhibited STAT3 activation, reduced HAMP expression, restored FPN1 protein levels, decreased Fe2 + accumulation, and attenuated lipid peroxidation. Conversely, hepcidin add-back partially reversed the protective effects of STAT3 inhibition by suppressing FPN1, increasing intracellular Fe2 + , and reinstating lipid ROS accumulation. CONCLUSION: IL-6 amplifies H/R-induced ferroptosis in H9C2 cardiomyoblasts by activating STAT3-dependent hepcidin expression and impairing FPN1-mediated iron export. Targeting the IL-6/STAT3-Hepcidin-FPN1 axis may provide a potential strategy for limiting inflammation-aggravated myocardial ferroptotic injury.