IFN-gamma priming of monocytes enhances LPS-induced TNF production by augmenting both transcription and MRNA stability.
IFN-gamma priming of monocytes enhances LPS-induced TNF production by augmenting both transcription and MRNA stability.
复制标题
单核细胞的 IFN-gamma 引发通过增强转录和 mRNA 稳定性来增强 LPS 诱导的 TNF 产生。
作者：
M. P. Hayes;Sherry L. Freeman;Raymond P. Donnelly
细菌内毒素或脂多糖诱导单核/巨噬细胞表达细胞因子是一种关键的、高度调控的宿主防御反应。干扰素-伽马(干扰素-伽马)增强内毒素反应，也就是所谓的启动，是公认的方法。然而，启动发生的机制(S)还不清楚。以肿瘤坏死因子(TNF)诱导为模型，设计实验，详细分析了预激对人单核细胞内毒素反应的影响。干扰素-γ的启动作用主要表现在肿瘤坏死因子基因表达水平。干扰素-γ预处理影响内毒素反应的大小，而不是敏感性。在治疗几个小时后发生启动，启动状态是由干扰素-伽马或GM-CSF诱导的，而不是M-CSF。与新鲜分离的单核细胞相比，经内毒素激活的单核细胞转录肿瘤坏死因子基因的速率更高。转录速率的增加与核因子-kappa B活性的显著增加相关，这一点通过使用一致的核因子-kappaB寡核苷酸的凝胶迁移率改变分析来确定。另一个有意义的发现是，在预激细胞中诱导的TNF mRNA比在非预激细胞中诱导的要稳定得多(T1/2增加6-8倍)。与mRNA稳定性增加一致的是，在内毒素刺激后，单核细胞中mRNA积累的持续时间更长，而且幅度更大。最后，启动和未启动的细胞对激酶抑制剂H-89具有不同的敏感性。H-能显著抑制脂多糖诱导的非刺激细胞中肿瘤坏死因子基因的积聚，但对单核细胞在脂多糖刺激后的聚集无影响。
The induction of cytokine expression in monocytes/macrophages by bacterial endotoxin or lipopolysaccharide is a critical, highly regulated host defence response. The augmentation of LPS responses by interferon gamma (IFN-gamma), referred to as priming, is well established. However, the mechanism(s) by which priming occurs is poorly defined. Using tumour necrosis factor (TNF) induction as a model, experiments were designed to analyse in detail the priming effect on the LPS response in human monocytes. Priming by IFN-gamma was primarily manifested at the level of TNF mRNA accumulation. IFN-gamma pre-treatment affected the magnitude rather than the sensitivity of the LPS response. Priming occurred after several hours of treatment, and the primed state was induced by either IFN-gamma or GM-CSF, but not M-CSF. Primed monocytes transcribed TNF mRNA at a higher rate than freshly isolated monocytes upon activation with LPS. The increased transcriptional rate correlated with a marked increase in nuclear factor-kappa B activity in these cells as determined by electrophoretic mobility shift assay using a consensus NF-kappa B oligonucleotide. An additional significant finding was than TNF mRNA induced in primed cells was much more stable than in unprimed cells (T1/2 increased 6-8-fold). Consistent with the increased mRNA stability, the duration of mRNA accumulation was longer following LPS stimulation in primed monocytes, in addition to being of greater magnitude. Finally, primed and unprimed cells possessed a differential sensitivity to the kinase inhibitor H-89. H-89 substantially suppressed LPS-induced TNF mRNA accumulation in unprimed cells, but had no effect on primed monocytes following LPS stimulation.(ABSTRACT TRUNCATED AT 250 WORDS)