Hatziieremia S, Gray A I, Ferro V A, Paul A, Plevin R
Department of Pharmaceutical Sciences, Strathclyde Institute for Biomedical Science, University of Strathclyde, Glasgow, Lanarkshire, UK.
Br J Pharmacol. 2006 Sep;149(2):188-98. doi: 10.1038/sj.bjp.0706856. Epub 2006 Aug 7.
In this study we examined the effect of the natural product cardamonin, upon lipopolysaccharide (LPS)-induced inflammatory gene expression in order to attempt to pinpoint the mechanism of action.
Cardamonin was isolated from the Greek plant A. absinthium L. Its effects were assessed on LPS-induced nitrite release and iNOS and COX-2 protein expression in two macrophage cell lines. Western blotting was used to investigate its effects on phosphorylation of the mitogen activated protein (MAP) kinases, ERK, JNK and p38 MAP kinase, and activation of the NFkappaB pathway, at the level of IkappaBalpha degradation and phosphorylation of NFkappaB. Also its effects on NFkappaB and GAS/GAF-DNA binding were assessed by EMSA.
Cardamonin concentration-dependently inhibited both NO release and iNOS expression but had no effect on COX-2 expression. It did not affect phosphorylation of the MAP kinases, degradation of IkappaBalpha or phosphorylation of NFkappaB. However, it inhibited NFkappaB DNA-binding in both LPS-stimulated cells and nuclear extracts of the cells (in vitro). It also inhibited IFNgamma-stimulated iNOS induction and GAS/GAF-DNA binding.
These results show that the inhibitory effect of cardamonin on LPS-induced iNOS induction is not mediated via effects on the initial activation of the NFkappaB or MAP kinase pathways but is due to a direct effect on transcription factor binding to DNA. However, although some selectivity in cardamonin's action is implicated by its inability to affect COX-2 expression, its exact mechanism(s) of action has yet to be identified.
在本研究中，我们检测了天然产物小豆蔻明对脂多糖（LPS）诱导的炎症基因表达的影响，以试图明确其作用机制。
从小豆蔻属植物希腊苦艾中分离出小豆蔻明。在两种巨噬细胞系中评估其对LPS诱导的亚硝酸盐释放以及诱导型一氧化氮合酶（iNOS）和环氧化酶-2（COX-2）蛋白表达的影响。采用蛋白质免疫印迹法研究其对丝裂原活化蛋白（MAP）激酶、细胞外信号调节激酶（ERK）、应激活化蛋白激酶（JNK）和p38 MAP激酶磷酸化的影响，以及在κB抑制蛋白α（IkappaBalpha）降解和核因子κB（NFkappaB）磷酸化水平上对NFkappaB信号通路激活的影响。此外，通过电泳迁移率变动分析（EMSA）评估其对NFkappaB以及干扰素γ激活序列（GAS）/γ干扰素激活因子（GAF）-DNA结合的影响。
小豆蔻明浓度依赖性地抑制一氧化氮释放和iNOS表达，但对COX-2表达无影响。它不影响MAP激酶的磷酸化、IkappaBalpha的降解或NFkappaB的磷酸化。然而，它在LPS刺激的细胞以及细胞的核提取物（体外）中均抑制NFkappaB与DNA的结合。它还抑制干扰素γ刺激的iNOS诱导以及GAS/GAF-DNA结合。
这些结果表明，小豆蔻明对LPS诱导的iNOS诱导的抑制作用不是通过对NFkappaB或MAP激酶信号通路初始激活的影响介导的，而是由于对转录因子与DNA结合的直接作用。然而，尽管小豆蔻明不能影响COX-2表达暗示了其作用存在一定选择性，但其确切作用机制尚未明确。
