BIOCHEMISTRY OF MAST CELL MEDIATOR RELEASE

肥大细胞释放的预形成和新形成的介质发挥了作用 保护性或病理性即刻超敏反应的核心作用 反应。肥大细胞介质的释放似乎也有助于一些 补体介导的反应，以表达或调节 淋巴细胞介导的反应，对某些形式的非特异性炎症， 以及一些生理反应。这样做的长期目标是 建议解决肥大细胞膜融合的生化基础 -预制调解人释放的机制；以及释放 花生四烯酸--几种新形成的介体的前体。近期 这个实验室和其他实验室的实验提供了生物 在大鼠肥大细胞中的先例和直接证据表明 SN-1，2-二酰基甘油(DAG)和磷脂酸(PA)的代谢可 在肥大细胞介体释放中起着关键作用。的具体目标 这项建议是：1.)为了考察DAG的起源和命运， 刺激大鼠肥大细胞，特别强调磷脂酶C， 磷脂酸盐磷酸水解酶、DAG激酶和DAG-脂肪酶；测量 其他融合性脂质在刺激大鼠体内的水平、来源和去向 肥大细胞，强调DAG、sn-1或2-单酰甘油和 溶血磷脂；考察新成立的P A的起源和命运 在受刺激的肥大细胞中；以确定会导致 花生四烯酸(AA)可用于合成新形成的介体 在刺激的肥大细胞中；为了探测细胞内系统， 调节这些反应；以及6.)以确定大鼠桅杆是否 细胞表达由DAG(“蛋白质”)激活的蛋白激酶活性 激酶C“)，并在存在的情况下详细表征活性。 膜反应的鉴定和表征 肥大细胞中的融合和AA可用性是 在分子水平上理解免疫球蛋白介导的反应。改进 对中介物释放机制的了解可能会使 开发新的有目的的监管方法，进而 最终可能被应用于改善对人类过敏或 其他炎症性疾病。

Preformed and newly formed mediators released from mast cells play a central role in protective or pathologic immediate hypersensitivity reactions. Mast cell mediator release also appears to contribute to some complement-mediated reactions, to the expression or regulation of lymphocyte-mediated reactions, to some forms of nonspecific inflammation, and to some physiologic responses. The long term objectives of this proposal are to resolve the biochemical basis of mast cell membrane fusion - the mechanism of preformed mediators release; and the release of arachidonic acid - the precursor of several newly formed mediators. Recent experiments in this and other laboratories have provided biologic precedents and direct evidence in rat mast cells that alterations in the metabolism of sn-1,2-diacylglycerol (DAG) and of phosphatidic acid (PA) may play pivotal roles in mast cell mediator release. The specific aims of this proposal are: 1.) to examine the origins and fates of DAG in stimulated rat mast cells with particular emphasis on phospholipase C, phosphatidate phosphohydrolase, DAG kinase and DAG-lipase; 2.) to measure the levels, origins and fates of other fusogenic lipids in stimulated rat mast cells with emphasis on DAG, sn-1 or 2-monoacylglycerol and lysophospholipids; 3.) to examine the origins and fate of newly formed P A in stimulated mast cells; 4.) to determine the reactions that make arachidonic acid (AA) available for the synthesis of newly formed mediators in stimulated mast cells; 5.) to probe the intracellular systems that regulate these reactions; and 6.) to determine whether or not rat mast cells express protein kinase activity that is activated by DAG ("protein kinase C") and if present to characterize the activity in detail. Identification and characterization of the reactions that lead to membrane fusion and AA availability in mast cells are fundamental to an understanding of Ige-mediated reactions at the molecular level. Improved knowledge of the mechanisms of mediator release might permit the development of new approaches to purposeful regulation that in turn eventually might be applied to improve the management of human allergic or other inflammatory disorders.