Zille Marietta, Karuppagounder Saravanan S, Chen Yingxin, Gough Peter J, Bertin John, Finger Joshua, Milner Teresa A, Jonas Elizabeth A, Ratan Rajiv R
From the Burke Medical Research Institute, White Plains, New York (M.Z., S.S.K., Y.C., R.R.R.); Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York (M.Z., S.S.K., Y.C., T.A.M., R.R.R.); Host Defense Discovery Performance Unit, Infectious Diseases Therapy Area Unit (P.J.G.) and Pattern Recognition Receptor Discovery Performance Unit, Immuno-Inflammation Therapeutic Area (J.B., J.F.), GlaxoSmithKline, Collegeville, PA; Laboratory of Neuroendocrinology, The Rockefeller University, New York (T.A.M.); and Department of Internal Medicine, Section of Endocrinology, Yale University, New Haven, CT (E.A.J.).
Stroke. 2017 Apr;48(4):1033-1043. doi: 10.1161/STROKEAHA.116.015609. Epub 2017 Mar 1.
Intracerebral hemorrhage leads to disability or death with few established treatments. Adverse outcomes after intracerebral hemorrhage 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.
We investigated cell death mechanisms in cultured neurons exposed to hemoglobin or hemin. Chemical inhibitors implicated in all known cell death pathways were used. Identified cell death mechanisms were confirmed using molecular markers and electron microscopy.
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 after intracerebral hemorrhage in vitro and in vivo. Electron microscopy showed that hemin induced a necrotic phenotype. Necroptosis and ferroptosis inhibitors each abrogated death by >80% and had similar therapeutic windows in vitro.
Experimental intracerebral hemorrhage 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 of these pathways can bring cells below that threshold to survival.
脑出血会导致残疾或死亡，目前有效的治疗方法很少。脑出血后的不良后果是由原发性和继发性损伤导致的神经元不可逆损伤引起的。继发性损伤被认为与血红蛋白及其来自裂解红细胞的氧化产物血红素有关。本研究的目的是确定由血红蛋白和血红素引起的继发性损伤所导致的潜在细胞死亡机制，以拓宽治疗选择。
我们研究了暴露于血红蛋白或血红素的培养神经元中的细胞死亡机制。使用了与所有已知细胞死亡途径相关的化学抑制剂。使用分子标记和电子显微镜确认了确定的细胞死亡机制。
铁死亡和坏死性凋亡的化学抑制剂可保护细胞免受血红蛋白和血红素诱导的毒性。相比之下，半胱天冬酶依赖性凋亡、蛋白质或mRNA合成、自噬、线粒体自噬或PARP-1依赖性坏死性凋亡的抑制剂则没有效果。因此，在体外和体内脑出血后，铁死亡和坏死性凋亡的分子标记物均增加。电子显微镜显示血红素诱导了坏死表型。坏死性凋亡和铁死亡抑制剂各自消除了超过80%的细胞死亡，并且在体外具有相似的治疗窗。
实验性脑出血具有铁死亡和坏死性凋亡细胞死亡的特征，但不具有半胱天冬酶依赖性凋亡或自噬的特征。我们提出，裂解血液诱导的铁死亡或坏死性凋亡信号足以达到导致神经元坏死的死亡阈值，并且抑制这些途径中的任何一种都可以使细胞低于该阈值而存活。
