SIRT1 agonist SRT1720 alleviates cerebral ischemia-reperfusion injury by inhibiting lactate-mediated SOD2 Lactylation and suppressing NCOA4-mediated ferritinophagy-ferroptosis.

Cerebral ischemia-reperfusion injury (CIRI) represents a critical pathological process underlying stroke-induced neuronal loss and long-term neurological deficits, characterized by profound oxidative stress and dysregulated iron homeostasis. Although metabolic disturbances such as lactate accumulation are hallmarks of ischemic brain injury, their effects on protein post-translational modifications, particularly lysine lactylation, remain largely unexplored. In this study, male C57BL/6 J mice were subjected to transient middle cerebral artery occlusion (tMCAO) to induce focal CIRI, and microglial cells were exposed to oxygen-glucose deprivation/reoxygenation (OGD/R) in vitro. We found that superoxide dismutase 2 (SOD2) lactylation at lysine 114 (SOD2-K114la) was significantly increased in ischemic brain tissues and OGD/R-treated microglia, accompanied by reduced enzymatic activity. Exogenous lactate treatment elevated SOD2-K114la levels both in vitro and in vivo. Mechanistically, enhanced SOD2 lactylation aggravated oxidative stress and cell injury by activating the NCOA4-mediated ferritinophagy pathway, promoting iron accumulation, lipid peroxidation, and ferroptosis. Importantly, treatment with the SIRT1 agonist SRT1720 effectively inhibited SOD2 lactylation, restored its antioxidant activity, suppressed ferritinophagy and ferroptosis, and attenuated microglial injury. These findings identify the SOD2-K114la/NCOA4 axis as a critical mediator of CIRI progression and suggest that SIRT1 activation may represent a potential therapeutic strategy for mitigating lactylation-dependent ischemic injury.