RUNX1 silencing protects against cerebral ischemia/reperfusion injury-induced endoplasmic reticulum stress, inflammation, ferritinophagy and ferroptosis through the CELF2/mTOR axis.

Abstract

Ischemic stroke is a prevalent cerebrovascular disease and remains a major cause of chronic disability and death worldwide. Runt-related transcription factor-1 (RUNX1) is a critical member of the core-binding factor family abnormally elevated in ischemic brain tissue. However, the exact roles of RUNX1 and its underlying cellular mechanisms in cerebral ischemia/reperfusion (I/R) injury have not been explored. Here we found that RUNX1 was highly expressed in brain tissues from middle cerebral artery occlusion (MCAO) mice and oxygen-glucose deprivation and reperfusion (OGD/R)-treated HT22 cells. In vivo experiments also showed that knockdown of RUNX1 significantly reduced the infarct volume and ameliorated neurological deficits in MCAO mice. Next, we investigated the exact mechanisms underlying the neuroprotective effect of si-RUNX1 against cerebral I/R injury. The results showed that knockdown of RUNX1 suppressed endoplasmic reticulum stress (ERS) and ERS-mediated neuroinflammation, as well as ferritinophagy and ferroptosis in both MCAO mice and OGD/R-treated HT22 cells. Mechanistically, RUNX1 directly targeted ELAV-like family protein 2 (CELF2) and regulated its transcription, therefore regulating the mTOR signaling. We also found that CELF2/mTOR mediated the inhibitory effects of si-RUNX1 on ERS-mediated inflammation and ferritinophagy-mediated ferroptosis both in vivo and in vitro. In summary, these data taken together revealed that si-RUNX1 suppressed ERS-mediated neuroinflammation and ferritinophagy-mediated ferroptosis through regulating the CELF2/mTOR signaling. These findings indicated that RUNX1/CELF2/mTOR might serve as therapeutic targets for cerebral I/R injury.