CYTOKINE-MEDIATED ENHANCEMENT OF NEURONAL INJURY

描述（改编自申请人的摘要）： 迟发性神经元死亡，因为在脑损伤后数小时甚至数天发生， 对局部缺血了解甚少。 最近的动物模型研究表明， 精氨酸诱导型一氧化氮合酶（iNOS）在 广泛神经元变性区域周围的星形胶质细胞1至3天 脑缺血性损伤后 休伊特博士之前的工作证明了 NO来源于星形胶质细胞iNOS的细胞因子诱导， 单独使用显著增加了N-甲基-D-天冬氨酸的量， 氧糖剥夺诱导的体外神经元损伤表明， 体内诱导型一氧化氮合酶的激活可能会产生危险的后果，即增强 兴奋毒性神经元损伤 此外，还表明增强作用是 与细胞外谷氨酸水平的增加有关，并且 依赖于活性氧以及NO。因此， 该项目旨在阐明特定的细胞和分子事件， 星形胶质细胞NO和活性氧有助于 马槟榔碱介导的兴奋毒性神经元损伤的增强。 实验 将在体外原代皮质细胞培养物中进行。 星形细胞 通过外源性添加促炎细胞因子诱导iNOS， cultures. 联合氧糖剥夺以及兴奋性氨基 酸给药将用于脑缺血的体外模型。 研究将旨在回答以下问题： 1. NO和活性氧如何相互作用， 兴奋性毒性和什么是细胞来源和酶的来源， 活性氧 2. 星形胶质细胞诱导型一氧化氮合酶如何导致 细胞外谷氨酸的增强？ 具体来说， 细胞因子刺激以改变谷氨酸E-通量和/或再摄取将被 评估。 本研究的长期目标是更好地了解 炎症性细胞因子参与的途径和机制 兴奋性毒性神经元损伤的增强。 改进定义 这些事件可能导致新的治疗策略的发展， 旨在减弱神经元破坏的进展， 中风

DESCRIPTION (Adapted from Applicant's Abstract): The pathophysiology of delayed neuronal death as it occurs hours or even days following cerebral ischemia is poorly understood. Recent study in animal models indicate that cytokine-inducible nitric oxide synthase (iNOS) is strongly induced in astrocytes surrounding areas of extensive neuronal degeneration 1 to 3 days following cerebral ischemic insult. Previous work by Dr Hewett demonstrated that NO derived from cytokine induction of astrocyte iNOS while not toxic alone dramatically increased the magnitude of N-methyl-D-aspartate and oxygen glucose deprivation induced neuronal injury in vitro suggesting that in vivo activation of iNOS could have the dangerous consequence of enhancing excitotoxic neuronal injury. Further it was shown that the potentiation was associated with an increase in extracellular glutamate levels and was dependent on reactive oxygen species as well as NO. Thus, the goal of this project is to elucidate specific cellular and molecular events by which astrocytic NO and reactive oxygen species contribute to the cytokine-mediated enhancement of excitotoxic neuronal injury. Experiments will be performed in vitro in primary cortical cell cultures. Astrocytic iNOS will be induced by exogenous addition of pro-inflammatory cytokines to cultures. Combined oxygen glucose deprivation as well as excitatory amino acid administration will be used in in vitro models of cerebral ischemia. Studies will be designed to answer the following questions: 1. How do NO and reactive oxygen species interact to augment excitotoxicity and what is the cellular source and enzymatic source of reactive oxygen species? 2. How does astrocytic iNOS induction lead to enhancement of extracellular glutamate? Specifically, the ability of cytokine stimulation to alter glutamate e-flux and/or re-uptake will be assessed. The long-term objectives of this study is to better understand the pathways and mechanisms by which inflammatory cytokines contribute to the enhancement of excitotoxic neuronal injury. Improved definition of these events could lead to the development of new therapeutic strategies designed to attenuate the progression of neuronal destruction following stroke.