Tetracycline inhibits the nitric oxide synthase activity induced by endotoxin in cultured murine macrophages
Tetracycline inhibits the nitric oxide synthase activity induced by endotoxin in cultured murine macrophages
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DOI：
10.1016/s0014-2999(98)00046-6
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发表时间：
1998-04-10
影响因子：
5
通讯作者：
Cillari, E
中科院分区：
文献类型：
--
作者：
D'Agostino, P;Arcoleo, F;Cillari, E
在这里，我们研究了四环素碱和半合成四环素衍生物强力霉素对体外培养的 J774 巨噬细胞中诱导型一氧化氮合酶的诱导以及脂多糖产生一氧化氮 (NO) 的影响。用四环素碱（6.25-250μM）或多西环素（5-50μM）处理J774系，剂量依赖性地降低了脂多糖刺激的（1μg/ml）诱导型NO合酶活性，从而降低了亚硝酸盐的形成。例如，250 μM 的四环素碱的抑制率为 70%，50 μM 的强力霉素的抑制率为 68%。四环素的抑制作用既不是由于细胞活力的降低（通过比色 3-[4,5-二甲基噻唑-2基]-2,5-二苯基四唑溴化物 (MTT) 还原测定法进行研究），也不是由于不加区别地抑制总蛋白质合成，但导致细胞中诱导型 NO 合酶蛋白含量的特定降低，通过十二烷基硫酸钠-聚丙烯酰胺凝胶电泳 (SDS-PAGE) 和蛋白质印迹测定，诱导型 NO 合酶表达显着降低证明了这一点。然而，在脂多糖刺激的巨噬细胞系中，四环素类药物对诱导型 NO 合酶 mRNA 积累没有影响，这表明四环素类药物对 NO 合成的抑制作用涉及转录后事件。当在脂多糖后6小时施用四环素类药物时，四环素类药物产生的脂多糖刺激的亚硝酸盐积累的减少明显较少，而在脂多糖后12小时则不存在，这表明四环素类药物改变了mRNA转录后诱导型NO合酶激活的早期事件。本研究的结果表明，NO 合成的调节是四环素发挥抗炎化合物作用的另一种可能途径。 (C) 1998 Elsevier Science B.V.
Here we investigate the effects of tetracycline base and of a semi-synthetic tetracycline derivative, doxycycline, on the induction of inducible nitric oxide synthase and, hence, on the production of nitric oxide (NO) by lipopolysaccharide in J774 macrophage cultured in vitro. The treatment of J774 line with tetracycline base (6.25-250 mu M) or doxycycline (5-50 mu M) dose-dependently decreased the lipopolysaccharide-stimulated (1 mu g/ml) inducible NO synthase activity and, consequently, nitrite formation. For instance, the inhibition was 70% for tetracycline base at 250 mu M and 68% for doxycycline at 50 mu M. The inhibitory effect of tetracyclines was due neither to a reduction in the viability of the cells, studied as colorimetric 3-[4,5-dimethylthiazol-2yl]-2,5-diphenyltetrazolium bromide (MTT) reduction assay, nor to an indiscriminate inhibition of total protein synthesis, but to a specific decrease in inducible NO synthase protein content in the cells, as attested by the significant reduction of the expression of inducible NO synthase, assayed by sodium-dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blot. However, no effect of tetracyclines on inducible NO synthase mRNA accumulation could be demonstrated in lipopolysaccharide-stimulated macrophage line, suggesting that the inhibitory effect of tetracyclines on NO synthesis involves post-transcriptional events. The reduction in lipopolysaccharide-stimulated nitrite accumulation produced by tetracyclines was significantly less when they were applied 6 h after lipopolysaccharide and absent 12 h after lipopolysaccharide, indicating that tetracyclines modify an early event in inducible NO synthase activation operating after mRNA transcription. The findings presented in this study indicate that the modulation of NO synthesis is another possible pathway by which tetracyclines may function as anti-inflammatory compounds. (C) 1998 Elsevier Science B.V.