Sheffler L A, Wink D A, Melillo G, Cox G W
Macrophage Cell Biology Section, National Cancer Institute-Frederick Cancer Research and Development Center, National Institutes of Health, MD 21702, USA.
J Immunol. 1995 Jul 15;155(2):886-94.
This study was performed to determine the effects of nitric oxide (NO) on the expression of inducible NO synthase (iNOS) in mouse macrophages. We used the NO donor diethylamine dinitric oxide (DEA/NO) and the mouse macrophage cell line ANA-1 in these experiments. ANA-1 macrophages did not express iNOS mRNA either constitutively or following exposure to 100 U/ml IFN-gamma alone, to 10 ng/ml LPS alone, or to 200 microM DEA/NO alone. Similarly, ANA-1 macrophages did not express detectable levels of iNOS mRNA following treatment with 100 U/ml IFN-gamma plus 200 microM DEA/NO. However, IFN-gamma (100 U/ml) plus LPS (10 ng/ml) induced high levels of iNOS mRNA in ANA-1 macrophages after 6 h. Low concentrations of DEA/NO (approximately 1 to 12 microM) caused up to a 2.5-fold augmentation of IFN-gamma plus LPS-induced iNOS mRNA expression. In contrast, 200 microM DEA/NO suppressed IFN-gamma plus LPS-induced iNOS mRNA expression (60% decrease). The effects of DEA/NO were gene-specific because DEA/NO did not affect the IFN-gamma plus LPS-induced expression of TNF-alpha mRNA. Moreover, the biphasic effects of DEA/NO were specifically due to released NO. Diethylamine and nitrite were unable to regulate IFN-gamma plus LPS-induced gene expression in ANA-1 macrophages. Time-response experiments suggested that the effects of NO were short-lived and occurred early during the induction of iNOS gene expression. The effects of NO were not limited to iNOS mRNA expression but were apparent at the level of iNOS protein expression and enzymatic activity. Overall, these results suggest that NO has immunoregulatory effects and may control the extent and duration of cytokine- and/or endotoxin-induced iNOS expression in macrophages.
本研究旨在确定一氧化氮（NO）对小鼠巨噬细胞中诱导型一氧化氮合酶（iNOS）表达的影响。在这些实验中，我们使用了NO供体二乙胺二亚硝酸酯（DEA/NO）和小鼠巨噬细胞系ANA-1。ANA-1巨噬细胞无论是组成性表达还是单独暴露于100 U/ml干扰素-γ、10 ng/ml脂多糖（LPS）或200 μM DEA/NO后，均不表达iNOS mRNA。同样，用100 U/ml干扰素-γ加200 μM DEA/NO处理后，ANA-1巨噬细胞也未表达可检测水平的iNOS mRNA。然而，6小时后，干扰素-γ（100 U/ml）加LPS（10 ng/ml）可诱导ANA-1巨噬细胞中高水平的iNOS mRNA表达。低浓度的DEA/NO（约1至12 μM）可使干扰素-γ加LPS诱导的iNOS mRNA表达增加达2.5倍。相反，200 μM DEA/NO可抑制干扰素-γ加LPS诱导的iNOS mRNA表达（降低60%）。DEA/NO的作用具有基因特异性，因为DEA/NO不影响干扰素-γ加LPS诱导的肿瘤坏死因子-α（TNF-α）mRNA表达。此外，DEA/NO的双相作用具体是由于释放的NO所致。二乙胺和亚硝酸盐无法调节ANA-1巨噬细胞中干扰素-γ加LPS诱导的基因表达。时间-反应实验表明，NO的作用是短暂的，且发生在iNOS基因表达诱导的早期。NO的作用不仅限于iNOS mRNA表达，在iNOS蛋白表达和酶活性水平也很明显。总体而言，这些结果表明NO具有免疫调节作用，可能控制巨噬细胞中细胞因子和/或内毒素诱导的iNOS表达的程度和持续时间。
