Role of hypoxia-inducible factor-prolyl-hydroxylase (HIF-PHD) in mitochondrial pathways of ischemic neuronal death

在神经退行性疾病如阿尔茨海默病和帕金森病中，以及在脑缺血或创伤性脑损伤后，决定脑组织和功能的不可逆损失的神经元死亡的潜在机制共享程序性细胞死亡的共同信号传导途径。在神经元中，这些程序性细胞死亡途径进入线粒体，线粒体是负责产生ATP的能量代谢的关键细胞器，从而确保神经元功能和存活。这样的线粒体死亡与线粒体膜透化和促凋亡蛋白（如凋亡诱导因子（AIF）、SMAC/DIABLO或细胞色素c）从膜间隙释放到细胞溶质和细胞核中相关，在细胞溶质和细胞核中它们协调确定的细胞死亡程序。现在人们普遍认为，线粒体损伤标志着所谓的程序性细胞死亡的不可逆点，这意味着线粒体受损的细胞无法存活。因此，新发现的神经元死亡信号传导的关键触发因素之间的机制联系，如破坏Ca 2+稳态或氧化应激，和线粒体损伤可以作为创新的目标，以克服目前的治疗选择在治疗退行性神经疾病的警告。 坏死性凋亡和铁凋亡是两种新出现的调节性坏死形式，分别通过RIP 1/RIP 3激酶激活和铁依赖性酶级联的激活来调节。我们最近的数据表明，在神经元细胞中，这些受调节的细胞死亡的范例可能与线粒体完整性和功能的丧失有关，特别是对代谢平衡、ROS稳态和Ca 2+调节以及死亡信号的影响。此外，缺氧诱导因子（HIF）脯氨酰-4-羟化酶（PHDs）成为线粒体保护的有前途的目标候选人在体外和体内与铁凋亡和坏死凋亡信号相关的氧化应激范例。我们推测，HIF-PHDs可能作为潜在的治疗靶点，在相关的缺氧/缺血性脑损伤的调节性坏死的范例。这些发现的结果将使我们能够解剖的机制参与PHDs的细胞死亡信号的范式坏死性凋亡和铁凋亡，其潜在的联系，线粒体的完整性和功能，在有害的应激反应模型系统的神经元细胞死亡诱导的氧化应激和氧葡萄糖剥夺在体外，和缺氧缺血后在体内。此外，我们将解决拟议中的关键作用PHDs在培养的小胶质细胞，脑切片中的神经炎症反应的调节，并在体内缺氧缺血后。结合申请人在该项目中的专业知识，可以提供一个独特的和统一的图片的作用博士在神经变性和神经炎症的机制，可能会导致神经保护和再生的新策略。

In neurodegenerative diseases such as Alzheimers and Parkinsons disease, and after cerebral ischemia or traumatic brain injury, the underlying mechanisms of neuronal death determining the irreversible loss of brain tissue and functions share common signaling pathways of programmed cell death. In neurons, these programmed cell death pathways funnel into mitochondria, the key organelles of energy metabolism that are in charge to produce ATP thereby securing neuronal function and survival. Such mitochondrial demise is associated with mitochondrial membrane permeabilization, and the release of pro-apoptotic proteins, such as apoptosis inducing factor (AIF), SMAC/DIABLO or cytochrome c from the intermembrane space into the cytosol and the cell nucleus, where they orchestrate a determined cell death program. It is now well accepted that mitochondrial damage marks the so-called point of no return of programmed cell death, meaning that cells with impaired mitochondria cannot survive. Thus, newly identified mechanistic links between key triggers of neuronal death signaling, such as disrupted Ca2+-homeostasis or oxidative stress, and mitochondrial damage may serve as innovative targets to overcome the current caveat of therapeutic options in the treatment of degenerating neural diseases. Necroptosis and ferroptosis are two emerging forms of regulated necrosis that are regulated by activation of RIP1/RIP3 kinase activation and iron-dependent enzymatic cascades, respectively. Our recent data suggest that in neuronal cells, these paradigms of regulated cell death may be linked to loss of mitochondrial integrity and function with particular impact on the metabolic balance, ROS homeostasis and Ca2+ regulation, and death signaling. In addition, hypoxia-inducible factor (HIF) prolyl-4-hydroxylases (PHDs) emerged as promising target candidates for mitochondrial protection in paradigms of oxidative stress associated with ferroptosis and necroptosis signaling in vitro and in vivo. We hypothesize that HIF-PHDs may serve as potential therapeutic targets in paradigms of regulated necrosis relevant to hypoxic/ischemic brain damage. The outcome of these findings will allow us to dissect the mechanistic involvement of PHDs in cell death signaling in paradigms of necroptosis and ferroptosis, and their potential link to mitochondrial integrity and function in detrimental stress responses in model systems of neuronal cell death induced by oxidative stress and oxygen glucose deprivation in vitro, and after hypoxia-ischemia in vivo. Further, we will address the proposed key role of PHDs in the regulation of neuroinflammatory responses in cultured microglial cells, in brain slices, and after hypoxia ischemia in vivo. Combining the expertise of the applicants in this project allows for providing a unique and unifying picture of the role of PHDs in mechanisms of neurodegeneration and neuroinflammation that may lead to novel strategies of neuroprotection and regeneration.