BACH1–CHAC1–Glutathione Axis Aggravates Myocardial Ischemia–Reperfusion Injury by Enhancing Ferroptosis and Oxidative Stress

Myocardial ischemia-reperfusion injury (MIRI) is a pathological process in which reperfusion-induced oxidative stress and metabolic derangement further aggravate myocardial damage and blunt the benefit of reperfusion. Ferroptosis is increasingly implicated in MIRI, with the glutathione (GSH)-glutathione peroxidase 4 (GPX4) axis constituting a key antioxidant barrier. Although GSH depletion is recognized as a critical event, its upstream regulation in MIRI remains unclear. Against this background, we investigate the BACH1-CHAC1-GSH pathway as a putative upstream regulatory axis of ferroptosis in MIRI and a potential molecular target. Here, using an oxygen-glucose deprivation/reoxygenation (OGD/R) model in AC16 and the reversibility conferred by the ferrostatin-1, RNA sequencing identified the GSH-degrading enzyme CHAC1 as a modulator that is induced by stress and promotes ferroptosis. Experiments showed that CHAC1 overexpression aggravated OGD/R-induced injury, depleted GSH, suppressed GPX4 and enhanced lipid peroxidation, whereas CHAC1 knockdown was partially protective. N-acetylcysteine (NAC) replenished GSH, restored GPX4 activity and partially rescued CHAC1-driven injury. In a mouse myocardial I/R model, cardiotropic adeno-associated virus-mediated CHAC1 overexpression worsened cardiac dysfunction, enlarged infarct and fibrosis areas, and increased myocardial iron deposition. Dual-luciferase assays revealed that the transcription factor BACH1 activates the CHAC1 promoter, and BACH1 silencing attenuated ferroptosis by suppressing CHAC1 and restoring the GSH-GPX4 axis. Collectively, our data identify the BACH1-CHAC1-GSH axis as an upstream amplifier of ferroptosis in MIRI through glutathione depletion and impairment of GPX4-dependent antioxidant defense. These findings refine the mechanistic link between reperfusion-phase redox imbalance and ferroptosis and highlight BACH1/CHAC1 inhibition or augmentation of GSH precursors as potential cardioprotective strategies in ischemic heart disease.