哮喘气道上皮细胞花生四烯酸LO酶代谢的分子调控机制研究

Both leukotrienes and lipoxins were important metabolic products of arachidonic acid lipoxygenase (LO) pathway, but lipoxins were natural counter-regulatory to leukotrienes.We determined whether the imbalance situation in leukotriene and lipoxin would result in asthma attack or remission in this project idea. The underlined reasons might be connected with the expressions and activities of 5LO and 15LO isoenzyme.The intracellular calcium and MAPK cell signal transduction pathways might be the molecular modulation mechanism of LO pathway.we will investigate the synthesis situation of LO and acceptor in sensitized or challenged rat models，detect the LXA4 inhibition on leukotrienes, assess the interference effects of glucocorticoid on epithelial cells LO metabolism,detect the molecular mechanism of second messenger calcium ion on leukotriene/lipoxin acceptors binding and expression, investigate the modulation of MAPK cell signal transduction pathways on LO phosphorylation status.We will further explore the relationship between clinical status and airway epithelial cell LO expression and phosphorylation levels in patients with asthma.All the experiments will be used to prove the underlined reasons of the switching mechanism of arachidonic acid LO pathway, and provide the exact basis for the clinical treatment.

白三烯和脂氧素均是花生四烯酸脂氧酶代谢的重要产物，而脂氧素具有拮抗白三烯的天然作用。本课题设想白三烯/脂氧素的不平衡状态可能导致哮喘发病或缓解，其原因与5LO、15LO酶活性密切相关，而细胞内钙离子和MAPK细胞信号转导通路是参与调节LO酶活性的分子机制。本课题应用致敏、激发阶段小鼠模型检测LO酶、受体的表达状态；检测LXA4对白三烯的抑制作用；评估皮质激素对上皮细胞LO酶代谢的干扰作用；检测第二信使钙离子对白三烯/脂氧素受体结合表达的分子机制；MAPK信号转导通路调控LO酶磷酸化状态的分子机制。探讨哮喘患者临床参数与上皮细胞LO酶-受体表达和磷酸化状态间的关系。上述实验将探讨花生四烯酸LO酶代谢途径"开关机制"的原因，为哮喘临床防治提供实验依据。

白三烯和脂氧素是花生四烯酸脂氧酶代谢的重要产物，本课题设想白三烯/脂氧素的不平衡状态可能导致哮喘发病或缓解，其原因与LO 酶活性密切相关，而MAPK 细胞信号转导通路是参与调节 LO酶活性的分子机制。探讨了哮喘关键产物CysLTs和LXs的不平衡状态，与哮喘慢性气道炎症之间有密切关系。发现影响LO的代谢因素可能与细胞MAPK信号传导通路等有关。LPS组IL-6、IL-1β mRNA以及胞内ROS表达水平升高（P＜0.05），HO-1 mRNA水平下降（P＜0.01），p38磷酸化水平上升（P＜0.01），胞核中Nrf2相对表达量下降（P＜0.01）。经LXA4干预后，与LPS组相比， NQO-1和GSH水平显著上升（P＜0.05）。LXA4可减轻脂多糖（LPS）引起的BEAS-2B细胞炎症反应并促进炎症消退，其机制可能与抑制p38 MAPK通路，减少促炎因子的分泌有关；以及与增强Nrf2的核转位以及磷酸化，减轻氧化应激损伤有关。这可能是哮喘药物治疗的一个潜在靶点，能为哮喘的临床防治提供实验依据。上述研究将明确花生四烯酸 LO 酶代谢途径“开关机制”的原因，为哮喘临床防治提供实验依据。