Casado M, Díaz-Guerra M J, Boscá L, Martín-Sanz P
Instituto de Bioquímica (CSIC-UCM), Facultad de Farmacia, Universidad Complutense, 28040 Madrid, Spain.
Biochem J. 1997 Nov 1;327 ( Pt 3)(Pt 3):819-23. doi: 10.1042/bj3270819.
The effect of cycloheximide (CHX) on the mRNA expression of the cytokine-inducible, calcium-independent nitric oxide synthase (iNOS) was investigated in fetal hepatocytes stimulated with lipopolysaccharide (LPS) or pro-inflammatory cytokines. In the presence of CHX the LPS-dependent iNOS mRNA levels were reduced, whereas the response to pro-inflammatory cytokines was enhanced. Because iNOS transcription is highly dependent on the activation of nuclear factor kappaB (NF-kappaB), this factor was evaluated by electrophoretic mobility shift assays, and a close correlation between NF-kappaB activity and iNOS mRNA levels was observed. CHX itself potentiated the degradation of the IkappaB alpha and IkappaB beta inhibitory subunits (IkappaB is inhibitory kappaB) of the NF-kappaB complex, and therefore the loss of LPS-dependent iNOS mRNA expression cannot be attributed to a blockage in the activation of NF-kappaB. These results suggest the existence of a CHX-sensitive pathway in the expression of iNOS mediated by LPS, a mechanism that is not involved in the response to pro-inflammatory cytokines.
在脂多糖（LPS）或促炎细胞因子刺激的胎儿肝细胞中，研究了环己酰亚胺（CHX）对细胞因子诱导的、钙非依赖性一氧化氮合酶（iNOS）mRNA表达的影响。在存在CHX的情况下，LPS依赖性iNOS mRNA水平降低，而对促炎细胞因子的反应增强。由于iNOS转录高度依赖于核因子κB（NF-κB）的激活，通过电泳迁移率变动分析评估该因子，并且观察到NF-κB活性与iNOS mRNA水平之间存在密切相关性。CHX本身增强了NF-κB复合物的IκBα和IκBβ抑制亚基（IκB即抑制性κB）的降解，因此LPS依赖性iNOS mRNA表达的丧失不能归因于NF-κB激活的阻断。这些结果表明在LPS介导的iNOS表达中存在一条CHX敏感途径，这是一种不参与对促炎细胞因子反应的机制。
