Botanical Phenolics on Oxidative/Nitrosative Signaling Pathways/Grace Sun

大脑中过量的氧化和亚硝化（O/N）活性已被认为是神经元兴奋毒性和神经胶质细胞炎症反应的基础，这些反应是许多神经退行性疾病（包括中风）的基础。近年来的研究发现，NADPH氧化酶是脑细胞中活性氧（ROS）的重要来源。NADPH氧化酶的激活与许多下游信号通路有关，包括诱导INOS和产生一氧化氮（NO）的NF-KB通路。在其他反应中，NO可以通过与蛋白质活性半胱氨酸硫醇残基相互作用形成s -亚硝基硫醇来调节蛋白质的结构和功能。许多与NADPH氧化酶信号通路相关的蛋白质似乎被s -亚硝基化修饰。虽然机制尚不清楚，但有大量证据表明，许多植物化合物可能保护大脑免受O/N损伤，包括脑缺血造成的损伤。为了与本中心的中心目标保持一致，项目2将确定新的植物药物，并测试中风介导的神经元兴奋毒性和胶质炎症反应部分是由于NADPH氧化酶的ROS和随后NADPH氧化酶信号通路中关键蛋白的s -亚硝基化的假设。在目标1中。神经元和星形胶质细胞/小胶质细胞将用于筛选植物提取物和从提取物中分离的纯化合物，以抑制nmda介导的神经元兴奋毒性和细胞因子诱导的胶质细胞炎症反应的能力。植物药物对神经元和神经胶质细胞中蛋白质的s -亚硝基化和差异表达的mRNA和蛋白质的影响将使用新开发的NitroDIGE协议和相互作用核心的mRNA大序列设备进行研究。在Aim 2中，将使用大脑中动脉闭塞引起的小鼠局灶性脑缺血模型来研究膳食中添加特定植物制剂是否对脑缺血/再灌注损伤具有保护作用。这些研究将包括使用缺乏N0X2和iNOS的小鼠来测试植物药物对行为结果、神经元存活、神经胶质激活和炎症反应的影响。目的3将验证已知植物药通过激活Nrf2/Keap1抗氧化信号通路减少脑缺血/再灌注损伤而具有神经保护作用的假设。在这些研究中，将使用星形胶质细胞或神经元靶向条件Keapl-null小鼠。在目标2和目标3中，我们还将确定不同脑区域中与氧化和抗氧化信号通路相关的s -亚硝基化和炎症蛋白以及mRNA的变化。项目2的体外和体内方法，以及本中心独特和最先进的核心设施的支持，将结合起来确定特定的细胞和分子机制，通过这些机制，新型植物药物和/或其活性成分可能发挥有益作用并防止中风损伤。

Excessive oxidafive and nitrosative (O/N) activifies in the brain have been recognized as the basis for the neuronal excitotoxicity and glial cell inflammatory responses that underiie many neurodegenerative diseases, including stroke. Recent studies have discovered the role of NADPH oxidase as an important source of reactive oxygen species (ROS) in brain cells. Activafion of NADPH oxidase is associated with a number of downstream signaling pathways, including the NF-KB pathway that induces INOS and produces nitric oxide (NO). Among other reactions, NO can regulate protein structure and function by interacfing with protein reactive cysteine thiol residues to form S-nitrosothiol. Many proteins associated with NADPH oxidase signaling pathways appear to be modified by S-nitrosylation. While the mechanisms are unknown, there is considerable evidence to suggest that a number of botanical compounds may protect the brain against O/N insults, including those resulfing from cerebral ischemia. In keeping with the central goal ofthis Center, Project 2 will identify new botanicals and test the hypothesis that stroke-mediated neuronal excitotoxicity and glial inflammatory responses are due in part to ROS from NADPH oxidase and subsequent S-nitrosylafion of key proteins in the NADPH oxidase signaling pathways. In Aim 1. neurons and astrocytes/microglia will be used to screen botanical extracts and pure compounds isolated from the extracts for their ability to suppress NMDA-mediated neuronal excitotoxicity and cytokine-induced inflammatory responses in glial cells. The effects of botanicals on S-nitrosylation of proteins and differentially-expressed mRNA and proteins in neurons and glial cells will be invesfigated using the newly developed NitroDIGE protocol and mRNA megasequencing facilities in the Interactions Core. In Aim 2, the mouse focal cerebral ischemia model induced by occlusion of the middle cerebral artery will be used to investigate whether dietary supplementation with specific botanicals offers protective effects against cerebral ischemia/reperfusion damage. These studies will include using mice deficient in N0X2 and iNOS to test the effects of botanicals on behavioral outcome, neuronal survival, glial activation, and inflammatory responses. Aim 3 will test the hypothesis that identified botanicals offers neuroprotective effects by reducing cerebral ischemia/reperfusion damage through activation of the Nrf2/Keap1 antioxidant signaling pathway. In these studies, astrocyte- or neuron-targeted conditional Keapl-null mice will be used. In Aims 2 and 3, we will also identify changes in S-nitrosylated and inflammatory proteins and mRNA associated with oxidafive and anfi-oxidafive signaling pathways in disfinct brain regions. The in vitro and in vivo approaches of Project 2, together with support from the unique and state-of-the-art core facilities of this Center, will combine to identify specific cellular and molecular mechanisms through which novel botanicals and/or their active components may exert beneficial effects and protect against stroke damage.