ENDOGENOUS REGULATION OF LEUKOTRIENE SYNTHESIS

白三烯（LT）C4在支气管和血管痉挛中起作用， 过敏和哮喘。 这种单独与LTC 4的生肌活性 血管通透性增加诱导已经涉及到 炎症反应的产生。 LTC 4生产 内皮细胞（EC）在体外需要一个外源性的 不稳定的前体LTA 4 已经显示 多形核白细胞（PMNL）可以提供LTA 4， 血管细胞LTC 4合成底物。 其他数据显示 EC产物前列环素（PG 12）对PMNL有抑制作用 生产LTA 4。 此外，血小板/PMNL产品5（s）， 12（s）-DHETE，一种有效的LTB 4诱导的PMNL拮抗剂 激活，也可能通过调节PMNL对 LTB4。 该建议将涉及PMNL的生化相互作用， 血管细胞和血小板来控制LT的合成， 其生理效应。 有人建议进行研究， 表征单独由每种细胞类型合成类二十烷酸 以及在共孵育期间。 PG 12作为生物活性物质的功能 PMNL LT合成的调节器和反馈的存在 将测试控制回路。 LTC 4诱导的提案 EC渗透性的增加调节PMNL跨膜迁移 将检查完整的EC单层。 研究将衡量 血小板/PMNL的产生和生理相关性 协同代谢物（例如5（s），12（s）-DHETE）作为天然的 LTB 4的拮抗剂。 这项工作将使用培养的血管细胞进行， 新鲜制备的人白细胞和血小板。 大多数分析 将采用高效液相色谱法（HPLC）， 这个实验室开发的方法。 还将收集数据 通过放射免疫测定法、酶免疫测定法和气体 色谱/质谱法。 白细胞迁移研究 将进行电阻测量， 使用在羊膜上生长的EC单层。 PMNL细胞内钙 将与Susan博士合作进行测量 斯坦伯格和将使用细胞内钙染料，呋喃-2。 这些新的相互作用提供了底物来源， 局部血管LTC 4合成的生化调节是 在炎症发展过程中可能很重要， 反应 平滑肌收缩和PMNL流入是 在哮喘期间支气管张力的改变中很重要， 急性超敏反应和心肌损害 梗塞 对PMNL移民的管理和控制， 血管通透性对体内平衡至关重要， 炎症反应。

Leukotriene (LT) C4 plays a role in broncho- and vasospasm during anaphylaxis and asthma. This myogenic activity alone with LTC4 induction of increased vascular permeability have been implicated in the production of the inflammatory response. LTC4 production by endothelial cells (EC) in vitro requires an exogenous source of the unstable precursor, LTA4. It has been shown that polymorphonuclear leukocytes (PMNL) can provide LTA4 as substrate for vascular cell LTC4 synthesis. Other data suggests that prostacyclin (PG12) an EC product, can inhibit PMNL production of LTA4. In addition, the platelet/PMNL product 5(s), 12 (s)-DHETE, a potent antagonist of LTB4-induced PMNL activation, may also play a role by modulating PMNL responses to LTB4. This proposal will relate the biochemical interactions of PMNL, vascular cells and platelets to the control of LT synthesis and their physiologic effects. Studies have been proposed to characterize the synthesis of eicosanoids by each cell-type alone and during coincubations. The function of PG12 as biological regulator of PMNL LT synthesis and existence of a feedback control loop will be tested. The proposal that LTC4-induced increases in EC permeability modulate PMNL migration across intact EC monolayers will be examined. Studies will measure the production and physiologic relevance of platelet/PMNL cooperative metabolite (e.g. 5(s), 12(s)-DHETE) as a natural antagonist of LTB4. This work will be carried out using cultured vascular cells and freshly prepared human leukocytes and platelets. Most analyses will employ high performance liquid chromatography (HPLC) with methods developed in this laboratory. Data will also be collected by radioimmunoassay, enzyme immunoasay, and by gas chromatography/mass spectrometry. Leukocyte migration studies and electrical resistance measurements will be performed and will use EC monolayers grown on amnion. PMNL intracellular calcium measurements will be done in collaboration with Dr. Susan Steinberg and will use the intracellular calcium dye, fura-2. These novel interactions which provide a source of substrate and biochemical modulation of local vascular LTC4 synthesis are potentially important during the development of inflammatory response. Smooth muscle contraction and PMNL influxes are important in the alterations in bronchial tone during asthma or acute hypersensitivity reactions and in the damage of myocardial infarction. Regulation and control of PMNL migration and vascular permeability are critical to homeostasis and in all inflammatory reactions.