Ferroptosis of microvascular pericytes contributes to ischemia-reperfusion injury in mice.

Ferroptosis is an iron-dependent form of programmed cell death implicated in various pathological conditions. We investigated whether ferroptosis contributes to acute ischemic stroke using a transient middle cerebral artery occlusion model in pial collateral-deficient CB-17/Icr-+/+Jcl mice. Mice were subjected to 90 min of ischemia followed by reperfusion, and the effects of the ferroptosis inhibitor UAMC-3203 on infarct evolution and post-stroke histological changes were examined. UAMC-3203 increased the survival of CD13-positive pericytes within infarct areas and enhanced infarct reduction in the subacute phase. In vitro, the glutathione peroxidase 4 inhibitor RAS-selective lethal 3 (RSL3) induced dose-dependent cell death in pericytes but not in endothelial cells, which was suppressed by UAMC-3203 but not by inhibitors of apoptosis or necroptosis. RSL3 induced lipid peroxidation in pericytes, as evidenced by malondialdehyde accumulation. Extracellular ferrous iron (Fe2+), but not ferric iron (Fe3+) or transferrin, caused intracellular Fe2+ accumulation and cell death in pericytes, which was further enhanced by oxygen-glucose deprivation with reperfusion and suppressed by UAMC-3203. Myelin debris containing abundant Fe2+ induced ferroptosis in cultured pericytes. These findings indicate that pericytes are a major ferroptosis-vulnerable cell type during ischemia-reperfusion and may represent a therapeutic target in acute ischemic stroke.