摘要
人A549/8细胞与人白细胞介素-1 β(50单位/ml)、干扰素- γ(100单位/ml)和肿瘤坏死因子- α (10 ng/ml)孵育后,诱导型一氧化氮合酶(NOS II) mRNA显著表达,而环己亚胺可阻止这种诱导。地塞米松显著降低细胞因子诱导的NOS II mRNA浓度;RU 38486(米非司酮)阻止了这种减少。核因子kappa B (NF-kappa B)激活抑制剂吡咯烷二硫代氨基甲酸酯(Pyrrolidine dithiocarbamate)也显著降低了巨细胞细胞诱导的NOS II mRNA水平。当A549/8细胞转染含有在报告基因之前克隆的鼠NOS II基因的1570 bp 5'-侧边序列的构建物时,小鼠NOS II启动子被细胞流式细胞术诱导达到20倍,而不是用细菌脂多糖。地塞米松和吡咯烷二硫代氨基甲酸酯抑制这种诱导。在电泳迁移率转移实验中,从细胞细胞诱导细胞提取的核蛋白,而不是从未刺激细胞提取的核蛋白,显著减缓了含有nf - κ b结合位点的寡核苷酸的迁移。使用地塞米松可明显减少这种带移。另一方面,地塞米松并没有降低细胞流式细胞术诱导的NF-kappa B p65和NF-kappa B p50的核蛋白含量(Western blot分析)。地塞米松也没有减少细胞细胞诱导的NF-kappa B p65 mRNA的表达或增强NF-kappa B inhibitor mRNA的表达。 The human and murine NOS II promoters also contain consensus sequences for activating protein-1 (AP-1) binding. However, AP-1 binding activity of nuclear extracts of A549/8 cells was not enhanced by cytomix or inhibited by dexamethasone. These data suggest that the activated glucocorticoid receptor prevents (by a protein/protein interaction) the binding of transcription factor NF-kappa B, but not AP-1, to the NOS II promoter, thereby inhibiting the induction of NOS II transcription.