Peroxidase-Based Toxicity In Hypereosinophilic States.'

嗜酸性粒细胞增多状态下基于过氧化物酶的毒性。

• 批准号: 6936005
• 负责人: ARNE SLUNGAARD
• 金额: $ 37.13万
• 依托单位: UNIVERSITY OF MINNESOTA
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-06-01 至 2007-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6936005
• 关键词: apoptosis; biomarker; cardiotoxin; cyanogen bromide; endocardium; enzyme activity; eosinophil; eosinophilia; gene expression; gene targeting; genetically modified animals; heart disorder; histopathology; inflammation; interleukin 5; laboratory mouse; mass spectrometry; myocardium; necrosis; nitrites; oxidative stress; oxidizing agents; pathologic process; peroxidases; thiocyanates; thromboplastin; tissue /cell culture

DESCRIPTION (provided by applicant): Eosinophi1 (EO) phagocytes destroy parasites but can also damage host tissue. Although allergies are the most common example of EO-mediated pathology, the hypereosinophilic Syndrome (HES) is the most striking. HES is a systemic hematologic disorder characterized by multi-organ system involvement, preeminently a characteristic, usually lethal form of heart disease. Eosinophilic heart disease (EHD occurs in a variety of hypereosinophilic states, irrespective of their cause. Endocardial and myocardial deposition of EO specific granule proteins, of which eosinophil peroxidase (EPO) is the most abundant, is proposed to mediate cardiotoxicity in EHD. Despite the abundance of EPO and the vigor of the EO respiratory burst, little is known about the contribution of EPO-mediated oxidative damage to the pathology of eosinophilic inflammatory states. We find that three unusual substrates - bromide (Br-), nitrite (NO2-), and thiocyanate (SCN-) - compete for oxidation by EPO in physiologic fluids in the presence of H202, yielding, respectively, HOBr, NO2., and HOSCN. The relative toxicity of these oxidants for human cells is HOBr> NO2>> HOSCN; yet EPO preferentially oxidizes SCN > NO2 - > Br-. We hypothesize that SCN "buffers" against generation by EPO of the more cytotoxic N02- and Br- based oxidants and consequently serum SCN- levels, which are dietarily determined, may modulate EPO toxicity. The overall goal of our proposed work is to examine the hypothesis that that EPO-generated oxidants impose damage in a substrate-determined manner to mammalian cells and tissue that contributes to the pathogenesis of EHD, which we propose as a paradigm for any organ damage occurring in eosinophil inflammatory states. The first specific aim is to test the hypothesis that whereas HOBr and N02 cause necrotic cell death by reacting with membrane components to destroy membrane integrity, HOSCN imposes sulfhydryl-targeted intracellular oxidative stress that can influence tissue factor gene expression and induce apoptosis. The second specific Aim is to test the hypothesis that an interleukin-5 (IL.5) transgenic mouse line will develop progressive functional, anatomic, and histologic manifestations of EHD with a parallel accumulation of EPO-specific protein oxidative damage as assessed by newly developed sensitive, substrate-specific amino acid "biomarkers." The third specific aim is to test the hypothesis that EPO contributes to the pathogenesis of EHD in the IL.5 transgenic mouse line. We will compare EHD severity, longevity, and EPO biomarker levels in the IL-5 transgenic line with that of an IL-S transgenics crossbred with an EPO 'knockout" line. The fourth specific aim is test the hypothesis that increasing serum SCN- inhibits, and decreasing SCN- promotes, EPO-mediated protein oxidant damage and the severity of EHD in IL-5 transgenic mice. These studies, if successful, will establish a murine model for HES and EHD, prove a mole for EPO-mediated oxidant damage in the pathogenesis of EHD, and suggest a simple strategy fur its treatment, (i.e., dietary supplementation with inexpensive SCN-), that could be applied even in impoverished communities as well as against more common allergic diseases, such as asthma.

描述（由申请人提供）：eosinophi1（EO）吞噬细胞破坏寄生虫，但也会损害宿主组织。尽管过敏是EO介导的病理学最常见的例子，但低粒细胞综合征（HES）是最引人注目的。 HES是一种系统性血液学疾病，其特征是多器官系统的参与，是心脏病的特征性，通常是致命的形式。 Eosinophilic heart disease (EHD occurs in a variety of hypereosinophilic states, irrespective of their cause. Endocardial and myocardial deposition of EO specific granule proteins, of which eosinophil peroxidase (EPO) is the most abundant, is proposed to mediate cardiotoxicity in EHD. Despite the abundance of EPO and the vigor of the EO respiratory burst, little is known关于epo介导的氧化性损害对嗜酸性炎性状态的病理学，我们发现三个异常的底物 - 溴化物（BR-），硝酸盐（NO2-）和硫氰酸酯（scn-） - 在生理流动中竞争HESMOSC and Hosmost and Hers and Herfors and Herss and and Herss and sworking，这些对人类细胞的毒性是HOBR> NO2 >> HOSCN； EPO优先氧化SCN> NO2-> br-。我们提出的工作的总体目的是检查以下假设：epo生成的氧化剂以底物确定的方式对哺乳动物细胞和组织施加损害，这有助于EHD的发病机理，我们建议这是嗜酸性粒细胞炎性疾病中发生的任何损伤的范式。第一个具体目的是检验以下假设：尽管HOBR和N02通过与膜成分反应来破坏膜完整性，而HOBR和N02引起坏死细胞死亡，而HOSCN则施加了硫磺酰胺靶向的细胞内氧化应激，可以影响组织因子基因表达和诱导凋亡。第二个具体目的是检验以下假设：介体5（IL.5）转基因小鼠系将发展EHD的逐渐逐渐累积的功能，解剖和组织学表现，并平行地积累EPO特异性蛋白氧化损伤，这些损害由新成立的敏感，敏感的，粘性的，底物特异性氨基氨基氨基酸的生物剂评估。第三个具体目的是检验EPO有助于IL.5转基因小鼠系中EHD发病机理的假设。 We will compare EHD severity, longevity, and EPO biomarker levels in the IL-5 transgenic line with that of an IL-S transgenics crossbred with an EPO 'knockout" line. The fourth specific aim is test the hypothesis that increasing serum SCN- inhibits, and decreasing SCN- promotes, EPO-mediated protein oxidant damage and the severity of EHD in IL-5 transgenic小鼠。