Metallothionein and Reactive Oxygen and Nitrogen Species

描述（由申请人提供）： 肺内皮细胞是高氧肺损伤早期结构和功能改变的发生部位。部分还原的氧物质的产生和它们的消除之间的不平衡似乎解释了这种病理的发生和/或维持，并且存在这样的损伤可能被部分还原的氮物质加剧的证据。然而，很明显，一氧化氮（NO）实际上可以限制内皮细胞损伤。NO保护肺血管内皮细胞的分子机制尚不清楚。从最近的报道和初步的数据，我们推测，诱导型一氧化氮合成酶衍生的NO可能是通过其潜在的抗凋亡作用介导的蛋白质的翻译后S-亚硝基化肺内皮细胞的保护。此外，我们最近表明，S-亚硝基化的金属硫蛋白（MT）中的锌硫醇簇是一个关键组成部分，细胞的氧化还原敏感性连接NO在肺内皮细胞锌稳态。锌对转录活性的贡献以及锌对细胞凋亡的抑制作用强调了SNO-MT在NO介导的细胞保护的信号通路中的重要性。因此，我们将确定：目的一：诱导型一氧化氮合酶衍生的NO在影响肺内皮细胞结构和功能的高氧作用。我们推测，诱导型一氧化氮合酶衍生的一氧化氮是细胞保护肺。iNOS-/-小鼠、内皮细胞转基因小鼠和抗PECAM靶向的iNOS至肺内皮的体细胞基因转移将用于在暴露于高氧的完整小鼠的肺循环中测试该假设。目的II：NO抗小鼠肺内皮细胞凋亡的机制。我们推测NO介导的锌释放是iNOS衍生的NO在LPS诱导的MLEC凋亡中的抗凋亡作用的基础。将对GFP标记的金属调节因子-1和荧光共振能量转移（FRET）进行全光谱共聚焦和多光子激光扫描显微镜（MPSLM）检查。目的III：锌在一氧化氮（NO）诱导的高氧损伤小鼠肺内皮细胞保护中的作用。我们推测锌的释放是一个重要的贡献因素，NO介导的抵抗高氧在完整的小鼠。将研究NO通过MPSLM和FRET在灌注肺中诱导的不稳定锌的变化以及锌耗竭或靶向破坏MT对完整小鼠对高氧的敏感性。

DESCRIPTION (provided by applicant): Pulmonary endothelium is the locus of early structural and functional changes in hyperoxic lung injury. An imbalance between the production of partially reduced oxygen species and their elimination appears to account for the genesis and/or maintenance of such pathology and evidence exists that such injury may be exacerbated by partially reduced nitrogen species. Nonetheless, it is apparent that nitric oxide (NO) may actually limit endothelial cell injury. The molecular mechanism underlying the protective role of NO, especially in pulmonary endothelium, remains unknown. From recent reports and preliminary data, we hypothesize that iNOS derived NO may be protective to lung endothelium by its potential antiapoptotic effects mediated by posttranslational S-nitrosylation of proteins. Furthermore, we have recently shown that S-nitrosylation of zinc thiolate clusters in metallothoinein (MT) is a critical component of cellular redox sensitivity linking NO to zinc homeostasis in pulmonary endothelial cells. The well known contributions of zinc to transcriptional activity and the inhibitory effects of zinc on apoptosis underscore the importance of SNO-MT in the signaling pathway underlying NO mediated cytoprotection. Accordingly we will determine the: Aim I: role of iNOS derived NO in affecting pulmonary endothelial cell structure and function in hyperoxia. We hypothesize that iNOS derived NO is cytoprotective in lung. iNOS-/- mice, endothelial cell transgenic mice and anti-PECAM targeted somatic gene transfer of iNOS to pulmonary endothelium will be used to test this hypothesis in pulmonary circulation of intact mice exposed to hyperoxia. Aim II: mechanism by which NO is antiapoptotic in cultured murine lung endothelial cells (MLEC). We hypothesize that NO mediated release of zinc underlies antiapoptotic effects of iNOS derived NO in LPS induced apoptosis in MLEC. Full spectral confocal and multiphoton laser scanning microscopy (MPSLM) of GFP-labeled metal regulatory factor-1 and fluorescence resonance energy transfer (FRET) will be done. Aim III: role of zinc in NO induced protection of hyperoxic injury to pulmonary endothelium in intact mouse lung. We hypothesize that release of zinc is an important contributing factor to NO mediated resistance to hyperoxia in intact mice. NO induced changes in labile zinc via MPSLM and FRET in perfused lung and zinc depletion or targeted disruption of MT on sensitivity of intact mice to hyperoxia will be studied.