Inhibition of ferroptosis after intracerebral hemorrhage

脑出血后铁性下垂的抑制作用 自发性脑出血(ICH)是病死率和发病率最高的卒中亚型。 由于在脑出血期间，大量的血液被释放到细胞外空间，因此 血红蛋白/游离血红素对大脑恢复非常重要。血红素被血红素加氧酶降解为铁， 胆绿素和一氧化碳。重要的是，铁在大脑中的积累有助于二次大脑 脑出血后的损伤。的确，铁毒性导致胶原酶诱导的小鼠出血性脑损伤，并且 使用铁络合剂减少铁的积累可以提高神经元的存活率。最近，铁下垂，一种铁- 在癌细胞和器官型海马片中发现了依赖形式的非凋亡性细胞死亡 谷氨酸暴露后的培养。它是由小分子或抑制谷胱甘肽的条件触发的 生物合成或谷胱甘肽过氧化物酶4(Gpx4)活性。这种受调控的细胞死亡的特点是广泛的 铁依赖的脂质过氧化，可被亲脂性抗氧化剂铁抑素-1或Liproxstatin-1抑制 1.铁眼性细胞死亡也被证明发生在脑细胞中。到目前为止，已经在小鼠身上报告了这种情况。 帕金森病和脑出血的模型。铁蛋白-1或利普生-1对铁性下垂的抑制作用是否降低 ICH对老年动物的损伤和改善功能结果尚不清楚。因此，本研究是 目的是在老年动物脑出血的背景下描述铁链细胞死亡的特征。我们的长期目标是限制 ICH损伤和改善功能预后。这项提议的科学目标是检验这样一个假设 铁蛋白-1或利普生-1抑制铁性下垂可保护脑出血并改善功能预后。我们 将进一步确定Gpx4活性增强是否抑制铁下垂并提供脑保护 在非物质文化遗产之后。在初步研究中，以线粒体缩小为特征的铁上皮样细胞死亡被检测到 小鼠脑出血后的透射电子显微镜观察。此外，脑出血后应用铁抑素-1治疗的小鼠 比用药物治疗的小鼠有更好的神经学结果。另一种独立的铁下垂抑制剂， Liproxstatin-1对脑出血损伤也有明显的保护作用。总而言之，这些新颖的观察结果强烈地 支持抑制铁性下垂可能减少老年动物脑出血损伤的前提。第一个具体目标 将确定抑制铁依赖的脂质过氧化是否改善组织学和功能 老年小鼠脑出血后的结果，无论性别。第二个具体目标将决定过度表达 Gpx4对脑出血后有脑保护作用。这项研究将提供铁链细胞死亡的新证据，在 除了其他受调控的细胞死亡途径外，在老年脑出血动物的大脑中也有显著的表达。它还将 深入了解Gpx4活性增加预防脑出血后铁性下垂的分子机制。 拟议项目的工作可以为脑出血患者提供新的药物/治疗方法。成功验证 老年动物脑出血模型中的脂质过氧化抑制剂将为以下研究提供理论基础和概念验证 未来的临床前和临床试验。

Inhibition of ferroptosis after intracerebral hemorrhage Spontaneous intracerebral hemorrhage (ICH) is the stroke subtype with the highest mortality and morbidity. Because large amounts of blood are released into the extracellular space during ICH, the metabolism of hemoglobin/free heme is very important for brain recovery. Heme is degraded by heme oxygenase into iron, biliverdin, and carbon monoxide. Importantly, iron accumulation within the brain contributes to secondary brain injury after ICH. Indeed, iron toxicity contributes to collagenase-induced hemorrhagic brain injury in mice, and reducing iron accumulation with iron chelators can improve neuronal survival. Recently, ferroptosis, an iron- dependent form of non-apoptotic cell death, was identified in cancer cells and in organotypic hippocampal slice cultures after glutamate exposure. It is triggered by small molecules or by conditions that inhibit glutathione biosynthesis or glutathione peroxidase 4 (GPX4) activity. This regulated cell death is characterized by extensive iron-dependent lipid peroxidation, which can be suppressed by lipophilic antioxidant ferrostatin-1 or liproxstatin- 1. Ferroptotic cell death also has been shown to occur in brain cells. To date, it has been reported in mouse models of Parkinson disease and ICH. Whether inhibition of ferroptosis by ferrostain-1 or liproxstain-1 reduces ICH injury and improves functional outcomes in aged animals remains unknown. Therefore, this research is intended to characterize ferroptotic cell death in the context of ICH in aged animals. Our long-term goal is to limit ICH injury and improve functional outcomes. The scientific objective of this proposal is to test the hypothesis that inhibition of ferroptosis by ferrostain-1 or liproxstain-1 protects ICH brain and improves functional outcomes. We will further determine whether augmentation of GPX4 activity inhibits ferroptosis and provides cerebroprotection after ICH. In pilot studies, ferroptotoic cell death, characterized by shrunken mitochondria, was detected by transmission electron microscopy in the mouse ICH brain. Additionally, mice treated with ferrostatin-1 after ICH had better neurologic outcomes than mice treated with vehicle. A second, independent, ferroptosis inhibitor, liproxstatin-1, also exhibited marked protection against ICH injury. Together, these novel observations strongly support the premise that inhibition of ferroptosis might reduce ICH injury in aged animals. The first specific aim will determine whether suppression of iron-dependent lipid peroxidation improves histologic and functional outcomes after ICH in aged mice of both sexes. The second specific aim will determine whether overexpression of GPX4 is cerebroprotective after ICH. This study will provide novel evidence that ferroptotic cell death, in addition to other regulated cell death pathways, is prominent in the brains of aged animals with ICH. It will also provide insight into the molecular mechanism by which increased GPX4 activity prevents post-ICH ferroptosis. Work on the proposed project could render new drugs/treatments for patients with ICH. Successful validation of lipid peroxidation inhibitors in the ICH models of aged animals will provide the rationale and proof-of-concept for future preclinical and clinical trials.