ENDOGENOUS REGULATION OF LEUKOTRIENE SYNTHESIS

白三烯C4在慢性支气管炎和血管痉挛中的作用 过敏反应和哮喘。这种与LTC4单独作用的生肌活动 血管通透性增加的诱导已被牵连 在产生炎症反应的过程中。LTC4生产 由血管内皮细胞(EC)体外培养需要外源性的 不稳定的前兆LTA4。事实证明， 多形核白细胞(PMNL)可提供LTA4 AS 维管细胞合成LTC4的底物。其他数据表明 前列环素(PG12)是一种EC产物，可抑制PMNL LTA4的生产。此外，血小板/中性粒细胞产品5(S)， 12(S)-LTB_4诱导的PMNL的有力拮抗剂DHETE 激活，也可能通过调节PMNL反应来发挥作用 LTB4. 这一提议将涉及PMNL的生化相互作用， 血管细胞和血小板对LT合成和分泌的调控 它们的生理效应。有人建议进行研究，以 按每种细胞类型单独表征二十烷类化合物的合成 以及在共同孵化期间。PG12的生物学功能 PMNL-LT综合调节器及反馈的存在性 将对控制回路进行测试。关于LTC4诱导的 EC通透性的增加调制PMNL跨 完整的EC单层将被检查。研究将衡量 血小板/中性粒细胞的产生及其生理意义 天然的协同代谢物(如5(S)，12(S)-DHETE) LTB4的拮抗剂。 这项工作将使用培养的血管细胞和 新鲜准备的人类白细胞和血小板。大多数分析 将采用高效液相色谱(HPLC)和 方法由本实验室自行研制。还将收集数据 放射免疫法、酶免疫法和GAS法 层析/质谱学。白细胞迁移研究 将进行电阻测量，并将 使用生长在羊膜上的EC单层。PMNL细胞内钙离子 测量将与苏珊博士合作完成 并将使用细胞内钙染料Fura-2。 这些新的相互作用提供了底物和 局部血管LTC4合成的生化调控 在炎症性疾病的发展过程中具有潜在的重要作用 回应。平滑肌收缩和PMNL内流是 在哮喘或哮喘期间的支气管张力改变中起重要作用 急性超敏反应与心肌损伤 脑梗塞。PMNL迁移和调控 血管通透性对动态平衡和ALL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.