Pathways for the Inflammatory Damage of Biomolecules

描述(申请人提供)：由激活的白血球产生的氧化剂对宿主防御微生物至关重要。然而，活性物质的过度生产会损害宿主组织。事实上，白细胞代表炎症的细胞标志，氧化剂与从动脉粥样硬化到神经退行性疾病再到癌症的炎症性疾病的组织损伤有关。我们在体外研究了四种吞噬细胞依赖的氧化损伤蛋白质的途径。这些途径及其特征产物是：髓过氧化物酶和3-氯酪氨酸；酪氨酸基和邻二氨基；羟基自由基和邻位酪氨酸；活性氮物种和3-硝基酪氨酸。使用两种临床相关的炎症模型，我们将研究吞噬细胞不能产生特定氧化剂的基因工程小鼠。在拟议的研究中，我们将提出三个相关问题。首先，我们将确定在体内产生氯酪氨酸、二叔酪氨酸、邻酪氨酸和硝基酪氨酸的途径。这些实验将揭示这些氧化剂生成系统中的任何一个的遗传缺陷是否会抑制任何化学标记物的产生，从而确定哪条途径在体内产生特定的标记物。第二，我们将确定组织、血浆和尿液中氧化氨基酸的水平是否平行变化。我们还将研究氧化氨基酸的吸收、代谢和尿液排泄。这些实验将确定这些具有良好特征的产品的血浆和尿液水平是否可以用作氧化应激的非侵入性标记物。第三，我们计划确定两种拟议的抗氧化剂-维生素C或维生素E-是否在我们的炎症模型中抑制氧化应激。总的来说，拟议的实验将确定导致吞噬细胞损害组织的氧化途径，并将检验尿液和血浆中氧化氨基酸水平表明体内氧化应激水平的假设。

DESCRIPTION (provided by applicant): Oxidants generated by activated white blood cells are critical to host defenses against microorganisms. However, overproduction of reactive species can damage host tissue. Indeed, white blood cells represent the cellular hallmark of inflammation, and oxidants have been implicated in tissue injury in inflammatory diseases ranging from atherosclerosis to neurodegenerative disorders to cancer.We have investigated four phagocyte-dependent pathways that oxidatively damage proteins in vitro. The pathways and their characteristic products are: myeloperoxidase and 3-chlorotyrosine; tyrosyl radical and o,o-dityrosine; hydroxyl radical and ortho-tyrosine; and reactive nitrogen species and 3-nitrotyrosine.Using two clinically relevant models of inflammation, we will study genetically engineered mice whose phagocytes are unable to produce specific oxidants. In the proposed research, we will ask three related questions. First, we will identify the pathways that generate chlorotyrosine, dityrosine, ortho-tyrosine, and nitrotyrosine in viva. The experiments will reveal whether a genetic deficiency of any of these oxidant-generating systems inhibits production of any of the chemical markers, thereby determining which pathway generates a particular marker in viva.Second, we will determine whether tissue, plasma, and urinary levels of the oxidized amino acids change in parallel. We will also investigate the absorption, metabolism, and urinary excretion of the oxidized amino acids. These experiments will determine whether plasma and urinary levels of these well-characterized products can be used as noninvasive markers of oxidative stress.Third, we plan to determine whether two proposed antioxidants-vitamin C or vitamin E- inhibit oxidative stress in our models of inflammation. Collectively, the proposed experiments will identify the oxidative pathways that cause phagocytes to damage tissues and will test the hypothesis that levels of oxidized amino acids in urine and plasma indicate levels of oxidative stress in vivo.