Downregulation of ELAVL1 attenuates ferroptosis-induced neuronal impairment in rats with cerebral ischemia/reperfusion via reducing DNMT3B-dependent PINK1 methylation.

Background: Ferroptosis is a non-apoptotic form of programmed cell death and has been found in ischemic stroke. Increasing evidence revealed that ELAVL1 is associated with ferroptosis, but it remains largely unclear whether ELAVL1 is involved in ischemic stroke. Here, we aimed to investigate the biological role and mechanism of ELAVL1 in cerebral ischemia/reperfusion (I/R) injury.

Methods: ELAVL1 shRNA were intravenously injected into rat brain, and then ischemic/reperfusion (I/R) model was constructed in rats to detect infarct volume, neurobehavioral deficit, and several ferroptosis factors (GSH, GPX4, SLC7A11, MDA, ROS, iron ion) in vivo. Oxygen-glucose deprivation/reperfusion (OGD/R) treated pheochromocytoma-12 (PC12) cells were used as in vitro models of I/R. RIP, biotin pull-down and ChIP assays was used to explore the relationship among ELAVL1, DNMT3B, and PINK1.

Results: ELAVL1 was highly expressed in rat brain tissue after I/R injury. Compared with those in the I/R group, the injection of RSL3 (30 mg/kg) or ferrostatin-1 (10 mg/kg) aggravated or alleviated infarct volume, neurobehavioral impairments, and increased or decreased ferroptosis factor levels, respectively. ELAVL1 silencing ameliorated brain damage in I/R-treated rats by inhibiting ferroptosis. Moreover, ELAVL1 silencing observably facilitated cell viability, GSH content, GPX4 and SLC7A11 expression, and reduced iron ion concentration, ROS and MDA levels in OGD/R-treated PC12 cells. ELAVL1 bound with DNMT3B mRNA 3'UTR and promoted DNMT3B expression. ELAVL1 inhibited PINK1 expression through stabilizing DNMT3B mRNA and blocking DNMT3B-mediated DNA methylation of PINK1 promoter. PINK1 knockdown reversed the effects of ELAVL1 inhibition on cell viability, GSH, GPX4, SLC7A11, iron ion concentration, ROS and MDA levels in OGD/R-treated PC12 cells.

Conclusion: ELAVL1 plays a critical role in protecting against ferroptosis-induced cerebral I/R and subsequent brain damage via DNMT3B/PINK1 axis, thus providing a new potential target for ischemic stroke treatment.