ZFP36L1 Enhances Microglial Ferroptosis in Ischemic Stroke by Reducing FTO-Mediated N6-Methyladenosine Demethylation of ACSL1 mRNA.

Microglia play an important role in ischemic stroke (IS). However, the molecular regulatory mechanisms underlying microglial ferroptosis in IS remain incompletely understood. In this study, blood samples were collected from 20 IS patients and 15 healthy volunteers. Microglia BV-2 subjected to oxygen-glucose deprivation/reoxygenation (OGD/R) and mice undergoing middle cerebral artery occlusion-reperfusion (MCAO/R) surgery were used to establish IS models. Our results revealed that in blood samples from IS patients and in OGD/R-treated BV-2 cells, ZFP36 ring finger protein like 1 (ZFP36L1) and Acyl-CoA synthetase long chain family member 1 (ACSL1) expression was increased, while the fat mass and obesity-associated (FTO) protein expression was decreased. ACSL1 silencing attenuated ferroptosis and inflammation in OGD/R-treated microglia, as evidenced by decreased levels of malondialdehyde, Fe2+, lipid peroxidation, inflammatory factors, along with an increased Glutathione/Glutathione disulfide ratio. Additionally, ZFP36L1 silencing suppressed the OGD/R-induced promotion of ferroptosis and inflammation in microglia and alleviated cerebral ischemic injury in MCAO/R mice, whereas ACSL1 overexpression reversed these alterations caused by ZFP36L1 silencing. Mechanistically, ZFP36L1 decreased FTO messenger RNA (mRNA) stability and reduced FTO expression. FTO overexpression reduced ACSL1 N6-methyladenosine (m6A) modification and ACSL1 expression. In conclusion, ZFP36L1 increased ACSL1 m6A modification and ACSL1 expression to promote microglial ferroptosis, neuroinflammatory response, and cerebral ischemic injury in IS by reducing FTO mRNA stability.