Kellerin alleviates cerebral ischemic injury by inhibiting ferroptosis via targeting Akt-mediated transcriptional activation of Nrf2

Ischemic stroke (IS) is characterized as a detrimental cerebrovascular disease with high mortality and disability. Ferroptosis is a novel mechanism involved in neuronal death. There is a close connection between IS and ferroptosis, and inhibiting ferroptosis may provide an effective strategy for treating IS. Our previous investigations have discovered that kellerin, the active compound of Ferula sinkiangensis K. M. Shen, possesses the capability to shield against cerebral ischemia injury. Our objective is to clarify the relationship between the neuroprotective properties of kellerin against IS and its ability to modulate ferroptosis, and investigate the underlying regulatory pathway. We investigated the impact and mechanism of kellerin in C57BL/6 mice underwent middle cerebral artery occlusion/reperfusion (MCAO/R) as well as SH-SY5Y cells exposed to oxygen-glucose deprivation/ re-oxygenation (OGD/R). The roles of kellerin on neurological severity, cerebral infarction and edema were investigated in vivo. The regulatory impacts of kellerin on ferroptosis, mitochondrial damage and Akt/Nrf2 pathway were explored. Molecular docking combined with drug affinity responsive target stability assay (DARTS) and cellular thermal shift assay (CETSA) were performed to analyze the potential target proteins for kellerin. Kellerin protected against IS and inhibited ferroptosis in vivo. Meanwhile, kellerin improved the neuronal damage caused by OGD/R and suppressed ferroptosis by inhibiting the production of mitochondrial ROS in vitro. Further we found that kellerin directly interacted with Akt and enhanced its phosphorylation, leading to the increase of Nrf2 nuclear translocation and its downstream antioxidant genes expression. Moreover, kellerin's inhibitory effect on ferroptosis and mitochondrial ROS release was eliminated by inhibiting Akt/Nrf2 pathway. Our study firstly demonstrates that the neuroprotective properties of kellerin against IS are related to suppressing ferroptosis through inhibiting the production of mitochondrial ROS, in which its modulation on Akt-mediated transcriptional activation of Nrf2 plays an important role. This finding shed light on the potential mechanism that kellerin exerts therapeutic effects in IS.