Nrf2 alleviates acute ischemic stroke induced ferroptosis via regulating xCT/GPX4 pathway

Ferroptosis is a form of regulating cell death, and iron accumulation in the brain after acute ischemic stroke (AIS) is associated with the triggering of iron metabolism. Nuclear factor erythroid 2-related factor 2 (Nrf2), one of the most critical antioxidant transcription factors in cells, is closely associated with ferroptosis and oxidative stress.In the present study, we explore the intrinsic mechanisms by which Nrf2 exerts neuroprotective effects against AIS-induced ferroptosis.In vivo experiments, we explored the protective effects of AIS induced by middle cerebral artery occlusion (MCAO) and its mechanisms by using intraperitoneal injections of ferrostatin-1 (Fer-1, an inhibitor of ferroptosis), Oltipraz (an agonist of Nrf2) and ML385 (an inhibitor of Nrf2) in wild-type (WT) mice, as well as using Nrf2^-/- mice. In vitro experiments, we investigated the mechanism of action of Nrf2 on the establishment of a ferroptosis cell model induced by Erastin by overexpressing or silencing Nrf2 expression using shRNA in SH-SY5Y cells.Ferroptosis played an important role in AIS, and Fer-1 inhibited iron accumulation and alleviated neuronal damage caused by AIS.Oltipraz attenuated AIS-induced neuronal damage and cerebral infarction by increasing cortical blood flow (CBF). Additionally, Oltipraz protected against AIS-induced ferroptosis by reducing oxidative stress and iron overload. Meanwhile, in Oltipraz-treated AIS mice, Nrf2, solute carrier family 7 member 11 (SLC7A11/xCT), and glutathione peroxidase 4 (GPX4) were upregulated. Conversely, ML385 decreased CBF and exacerbated IS-induced neuronal damage. Furthermore, both ML385 treatment and Nrf2 knockout mice exacerbated oxidative stress injury and iron overload and downregulated the expression of both xCT and GPX4. Consistent with the in vivo results, Nrf2 conferred ferroptosis resistance in vitro upon exposure to compounds that induce ferroptosis, by modulating the xCT/GPX4 pathway.The present study confirmed that Nrf2 could attenuate AIS-induced neuronal ferroptosis and oxidative stress by regulating xCT/GPX4.