Helioxanthin inhibits interleukin-1β-induced MIP-1β production by reduction of c-jun expression and binding of the c-jun/CREB1 complex to the AP-1/CRE site of the MIP-1β promoter in Huh7 cells
Helioxanthin inhibits interleukin-1β-induced MIP-1β production by reduction of c-jun expression and binding of the c-jun/CREB1 complex to the AP-1/CRE site of the MIP-1β promoter in Huh7 cells
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DOI：
10.1016/j.bcp.2008.08.023
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发表时间：
2008-10-30
影响因子：
5.8
通讯作者：
Yeh, Sheau-Farn
中科院分区：
文献类型：
--
作者：
Tseng, Pei-Chi;Hsu, Hsing-Chih;Yeh, Sheau-Farn
IL-1β诱导的巨噬细胞炎症蛋白-1β(MIP-1β)水平升高与慢性肝炎性疾病相关。然而，IL-1β诱导肝细胞MIP-1β表达的分子机制尚不清楚。在此之前，我们曾报道过辣根黄质(HE-145)的抗乙肝病毒作用机制。在这里，我们证明了HE-145以剂量依赖的方式抑制IL-1β诱导的Huh7细胞MIP-1β的表达。为了了解HE-145的作用模式，我们首先在分子水平检测了IL-1β是如何诱导MIP-1β表达的。使用选择性抑制剂，我们发现JNK和p38通路参与了IL-1β诱导的MIP-1β的表达。He-145特异性抑制IL-1β诱导的c-jun基因和蛋白表达，阻止c-jun介导的AP-1 DNA结合活性，但对IL-1β诱导的JNK、p38和ATF2的激活无影响。进一步研究表明，HE-145可能直接在转录水平下调c-jun基因的表达，而不需要从头合成蛋白质。突变分析和超移位分析表明，IL-1β刺激c-jun和CREB1结合到MIP-1β启动子的重要AP-1/Cre位点。高表达c-jun可完全逆转HE-145对IL-1β诱导的MIP-1β启动子活性的抑制作用。电泳迁移率改变分析(EMSA)和染色质免疫沉淀(ChIP)分析一致表明，HE-145在体外和体内都减少了与AP-1/Cre位点的c-jun结合。我们的结果证实c-jun在IL-1β诱导的肝细胞MIP-1β表达中起主要作用。HE-145抑制IL-1β诱导的MIP-1β的产生主要是通过抑制IL-1β诱导的c-jun表达和c-jun/CREB1复合体与AP-1/Cre结合所致。(C)2008 Elsevier Inc.保留所有权利。
An elevated level of macrophage inflammatory protein-1 beta (MIP-1 beta) induced by IL-1 beta has been correlated with chronic hepatic inflammatory disease. However, molecular mechanism of IL-1 beta-induced MIP-1 beta expression in hepatic cells is obscure. Previously, we reported the mechanism of the anti-hepatitis B virus (HBV) activity of helioxanthin (HE-145). Here, we demonstrated that HE-145 inhibited IL-1 beta-induced MIP-1 beta expression in a dose-dependent manner in Huh7 cells. To understand the mode of action of HE-145, we first examined how IL-1 beta induced MIP-1 beta expression at the molecular level. Using selective inhibitors, we found that JNK and p38 pathways participated in IL-1 beta-induced MIP-1 beta expression. HE-145 specifically suppressed IL-1 beta-induced c-jun mRNA and protein expression and prevented c-jun-mediated AP-1 DNA-binding activity, whereas it had no effect on IL-1 beta-induced activation of JNK, p38 and ATF2. Further studies indicated that HE-145 may downregulate c-jun mRNA expression directly at transcriptional level without requirement of de novo protein synthesis. Mutational analysis and supershift assays indicated that IL-1 beta stimulated c-jun and CREB1 binding to the essential AP-1/CRE site of the MIP-1 beta promoter. The inhibitory effect of HE-145 on IL-1 beta-induced MIP-1 beta promoter activity was completely reversed by overexpressing c-jun. Electrophoretic mobility shift assay (EMSA) and chromatin immunoprecipitation (ChIP) assay consistently revealed that HE-145 reduced c-jun binding to the AP-1/CRE site in vitro and in vivo. Our results established a majorrole for c-jun in IL-1 beta-induced MIP-1 beta expression in hepatic cells. The reduction in IL-1 beta-induced c-jun expression and subsequent binding of the c-jun/CREB1 complex to AP-1/CRE site mainly contributed to the inhibitory action of HE-145 on IL-1 beta-induced MIP-1 beta production. (C) 2008 Elsevier Inc. All rights reserved.