Targeting inhibition of T3JAM reduces brain cell ferroptosis in rat following ischemia/reperfusion via a mechanism involving prevention of TLR4-mediated iron overload

Abstract

Iron overload-dependent ferroptosis is believed to contribute to the brain injury of ischemia/reperfusion (I/R), whereas toll-like receptor 4 (TLR4) can exert pro-ferroptosis effect via inhibiting the glutathione peroxidase 4 (GPX4) level, but the mechanisms behind these phenomenon are not fully elucidated. Tumor necrosis factor receptor correlated factor 3-interaction Jun amino-terminal kinase [JNK]-activating modulator (T3JAM) can activate specific molecule and its downstream signaling pathways, including TLR4. This study aims to explore whether targeting T3JAM can reduce I/R-induced ferroptosis in brain via downregulating TLR4. A Sprague Dawley (SD) rat model of cerebral I/R injury was established by 2 h-ischemia plus 24 h-reperfusion, which displayed brain injury (increases in neurological deficit score and infarct volume) and upregulation of T3JAM and TLR4, concomitant with the increased ferroptosis, reflected by increases in the levels of transferrin receptor protein 1 (TfR1), total iron, Fe²⁺ and lipid peroxidation (LPO) while decreases in the levels of ferroportin (FPN) and GPX4. Consistently, similar results were achieved in the cultured HT22 cells subjected to 8h-oxygen-glucose deprivation plus 12 h-reoxygenation (OGD/R), and knockdown of T3JAM reversed these phenomena. Moreover, Telaprevir, an anti-hepatitis C virus (HCV) drug, could also provide beneficial effect on alleviating ischemic brain injury via inhibition of T3JAM. Based on these observations, we conclud that inhibition of T3JAM can reduce I/R-induced brain cell ferroptosis through downregulating TLR4 and that T3JAM could be a potential target for identifying novel or existing drugs (such as Telaprevir) to treat cerebral I/R injury.