EOSINOPHILS, EICOSANOID BIOSYNTHESIS AND METABOLISM

哮喘气道反应性的发病机制被认为涉及多种介质（从细胞因子到花生四烯酸衍生的脂质）刺激的多个细胞之间的复杂相互作用。嗜酸性粒细胞对哮喘肺的浸润在过敏性哮喘的病因学中起着核心作用嗜酸性粒细胞和嗜酸性粒细胞具有不同的类二十烷生物合成能力，同时也是对脂质介质有反应的细胞。花生四烯酸通过5-脂氧合酶（5-LO）途径代谢导致几种不同的生物活性代谢物的形成，包括白三烯C4和B4，它们被认为在介导过敏反应方面起重要作用。此外，5-LO还导致5-氧-二十碳四烯酸（5-氧- ete）的形成，该物质尚未被广泛研究，但最近被认为是人类嗜酸性粒细胞的一种有效的动态因子。完整描述5-氧- ete和相关类二十烷酸的生物合成和代谢的基本问题仍然存在，特别是完整描述5-氧- ete和相关类二十烷酸的生物合成和代谢，特别是在对花生四烯酸代谢物（包括嗜酸性粒细胞和巨噬细胞）有反应的细胞中。最近的研究已经导致在碳-7 （FOG7）上发现了一个额外的5-氧谷胱甘肽加合物，它也对嗜酸性粒细胞和中性粒细胞具有趋化作用。通过细胞间的生化合作，跨细胞生物合成在生物活性类二十烷酸的生产中也起着重要作用。关于5-oxo-ETE类二十烷酸在体内的形成，特别是在细胞内的形成，我们知之甚少。由于嗜酸性粒细胞在哮喘气道中丰富，本提案的主要重点将涉及动物和人类模型中5-氧-二十烷酸和FOG7产生的详细研究。这类或类二十烷酸的合成和代谢的生化途径也将被研究。高灵敏度的质谱技术将用于进行这些基本的生物合成和代谢研究，以及表征和鉴定参与生物合成和代谢事件的酶。

The pathogenesis of airways reactivity in asthma is thought to involve a complex interaction between multiple cells stimulated by a diverse array of mediators from cytokines to lipids derived from arachidonic acid. The infiltration of eosinophils into the asthmatic lung has been through to play a central role in the etiology in the etiology of allergic asthma and eosinophils and eosinophils have a diverse capacity for eicosanoid biosynthesis as well as being cells which respond to lipid mediators. The metabolism of arachidonic acid by the 5-lipoxygenase (5-LO) pathway leads to the formation of several different biologically active metabolites including leukotrienes C4 and B4 which are thought to play important roles in terms of mediating allergic reactions. In addition, 5-LO also leads to the formation of 5-oxo-eicosatetraenoic acid (5-oxo-ETE) which has not been extensively studied, but recently recognized as a potent chomatactic factor for the human eosinophil. Fundamental questions remain concerning a complete description of the biosynthesis and metabolism of 5-oxo-ETE and related eicosanoids, in particular a complete description of the biosynthesis and metabolism of 5-oxo-ETE and related eicosanoids, in particular in cells which respond to this arachidonate metabolite including the eosinophil and macrophage. Recent investigations have led to the discovery of an additional 5-oxo glutathione adduct at carbon-7 (FOG7) which is also chemotactic for eosinophils and neutrophils. Transcellular biosynthesis also plays a major role in the production of biologically active eicosanoids through cell-cell biochemical cooperation. Little is known about the formation of 5-oxo-ETE eicosanoids in vivo, in particular within cells resident. Since the eosinophil is abundant in the asthmatic airways, a major focus of this proposal will involve detail investigations of the production of 5-oxo- eicosanoids and FOG7 in both animal and human models. The biochemical pathways or synthesis and metabolism of this class or eicosanoid will also be investigated. Highly sensitive mass spectrometric techniques will be employed to carry out these basic biosynthetic and metabolism studies as well as characterization and identification of enzymes involved in the biosynthetic and metabolic events.