Neuronal Death After Hemorrhagic Stroke In Vitro and In Vivo Shares Features of Ferroptosis and Necroptosis

Abstract

Background and Purpose Intracerebral hemorrhage (ICH) leads to disability or death with few established treatments. Adverse outcomes following ICH result from irreversible damage to neurons resulting from primary and secondary injury. Secondary injury has been attributed to hemoglobin and its oxidized product hemin from lysed red blood cells. The aim of this study was to identify the underlying cell death mechanisms attributable to secondary injury by hemoglobin and hemin to broaden treatment options. Methods We investigated cell death mechanisms in cultured neurons exposed to hemoglobin or hemin. Chemical inhibitors implicated in all known cell death pathways were employed. Identified cell death mechanisms were confirmed using molecular markers and electron microscopy. Results Chemical inhibitors of ferroptosis and necroptosis protected against hemoglobin- and hemin-induced toxicity. By contrast, inhibitors of caspase-dependent apoptosis, protein or mRNA synthesis, autophagy, mitophagy or parthanatos had no effect. Accordingly, molecular markers of ferroptosis and necroptosis were increased following ICH in vitro and in vivo. Electron microscopy showed that hemin induced a necrotic phenotype. Necroptosis and ferroptosis inhibitors each abrogated death by greater than 80% and had similar therapeutic windows in vitro. Conclusion Experimental ICH shares features of ferroptotic and necroptotic cell death, but not caspase-dependent apoptosis or autophagy. We propose that ferroptosis or necroptotic signaling induced by lysed blood is sufficient to reach a threshold of death that leads to neuronal necrosis and that inhibition of either one of these pathways can bring cells below that threshold to survival.

Metabolic networks in ferroptosis (Review)

“…In acute kidney failure, hemorrhagic stroke and nephrotoxic folic acid induce acute kidney injury, and inhibitors of ferroptosis (for example, ferrostatin-1) reduce the damage caused by cell sabotage. Ferrostatin-1 preserves renal function and decreases injury, oxidative stress and tubular cell death in mice with nephrotoxic folic acid-induced acute kidney injuries (17,58,59). Therefore, ferrostatin-1 may have a prophylactic effect in these non-neoplastic diseases.…”

Ferroptosis: A Regulated Cell Death Nexus Linking Metabolism, Redox Biology, and Disease

“…These inhibitors are also protective in models of degenerative brain disorders, including Parkinson's, Huntington's, and Alzheimer's Diseases, as well as in other forms of neurodegeneration and traumatic and hemorrhagic brain injury (Chen et al, 2015; Do Van et al, 2016; Gascon et al, 2016; Guiney et al, 2017; Hambright et al, 2017; Li et al, 2017; Skouta et al, 2014; Zille et al, 2017). Ferroptosis in some other tissues and diseases has been examined, including liver hemochromatosis (Wang et al, 2017).…”

Emerging Strategies of Cancer Therapy Based on Ferroptosis

“…[8,17] Morphologically, the cells with ferroptosis compared with normal cells have smaller mitochondria, decreased or vanishing mitochondria crista, condensed mitochondrial membrane, and ruptured outer mitochondrial membrane. [8,18–20] …”