ROLE OF DIACYLGLYCEROL METABOLISM IN MAST CELL SECRETION

肥大细胞炎性介质的形成和释放 细胞在速发型超敏反应中起核心作用 并有助于慢性疾病的发展和延续 哮喘等疾病中的炎症。 长期目标是 这项工作是为了了解脂质代谢途径的作用 在特定的亚细胞区室中发挥作用， 调节肥大细胞介质释放。 注意力集中在 1，2-二酰基甘油（DAG）-一种脂质中间体， 折叠与生理刺激，参与调节 通过蛋白激酶C磷酸化蛋白质，并作为 花生四烯酸和花生四烯酸的释放底物 融合脂质的形成在胞吐作用中可能是重要的。 一种新的研究DAG机理的概念方法 形成和消费。 分子 确定了DAG的种“指纹”，发现 与磷脂酰肌醇（大多数人感觉到的脂质）的不一致 研究人员认为， 细胞活化），这强烈表明肥大细胞DAG是 主要由其他途径形成。 这一观察和 其他人强烈要求重新评估机制， 在特定的亚细胞位点形成并去除DAG。 要求1 建议界定相对重要性、位置和 通过1a）调节不同的DAG生成途径 在确定了分子量之后， 推定的前体磷脂的物种指纹， 1b）补充研究，在体外检查甘油三酯 活性、亚细胞定位和特定酶的调节 感兴趣 因为任何中间环节的混乱都是可控的 不仅取决于其形成的速度，而且同样重要的是， 其去除率，目标二旨在确定相对 特定DAG代谢途径的重要性、其位置 和监管。 这一问题的四种解决方法包括：2a） DAG代谢物的分子种类分析，2b）DAG代谢物的研究 原位产生或外源添加的DAG的代谢，2c） 确定推定的DAG代谢物的质量，以及2d） 在体外直接评估合适的酶。 这些关于DAG的性质和亚细胞定位的研究 新陈代谢-生化机制不可或缺的一个过程 调节介质释放-应该有助于更清楚地 免疫活化肥大细胞的观点。 这些知识将 有助于促进新药物的开发 过敏性疾病的治疗方法

The formation and release of inflammatory mediators by mast cells play central roles in immediate hypersensitivity reactions and contribute to the development and perpetuation of chronic inflammation in diseases such as asthma. The long range goal of this work is to understand what roles lipid metabolic pathways play in specific subcellular compartments in causing and/or regulating mast cell mediator release. Attention is focused on 1,2-diacylglycerol (DAG) - a lipid intermediate that increases 2-5 fold with physiologic stimulation, participates in the regulation of phosphorylation of proteins by protein kinase C and acts as a substrate both for the release of arachidonic acid and the formation of fusogenic lipids potentially important in exocytosis. A new conceptual approach to study the mechanism(s) of DAG formation and consumption has been developed. The molecular species "fingerprint" of DAG was determined and found to be discordant with that of phosphatidylinositol (the lipid felt by most investigators to give rise to the increases DAG mass occurring in cellular activation) strongly suggesting that mast cell DAG is principally formed by other pathways. This observation and others strongly motivate a reassessment of the mechanisms that form and remove DAG in specific subcellular sites. Aim 1 proposes to define the relative importance, location and regulation of different DAG generative pathways by 1a) Employing deductive analysis after determining the molecular species fingerprints of putative precursor phospholipids and triglyceride and 1b) Complementary studies examining in vitro the activity, subcellular location and regulation of specific enzymes of interest. Because the mess of any intermediate is controlled not only by the rate of its formation, but equally importantly by its rate of removal, Aim II seeks to identify the relative importance of specific DAG metabolic pathways, their location and regulation. Four approaches this question include: 2a) Molecular species analysis of DAG metabolites, 2b) Studies of the metabolism of DAG generated in situ or added exogenously, 2c) Determining the mass of putative DAG metabolites, and 2d) direct assessment in vitro of appropriate enzymes. These studies of the nature and subcellular location of DAG metabolism -a process integral to the biochemical mechanisms regulating mediator release - should contribute to a much clearer view of immunologic activation mast cells. This knowledge will help to facilitate the development of new pharmacologic approaches to allergic disorders.