Signaling pathway for 2,3,7,8-tetrachlorodibenzo-p-dioxin-induced TNF-α production in differentiated THP-1 human macrophages
Signaling pathway for 2,3,7,8-tetrachlorodibenzo-p-dioxin-induced TNF-α production in differentiated THP-1 human macrophages
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DOI：
10.1038/emm.2007.58
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发表时间：
2007-08-31
影响因子：
12.8
通讯作者：
Sohn, Jeongwon
中科院分区：
文献类型：
--
作者：
Cheon, HyeonJoo;Woo, Young-Seok;Sohn, Jeongwon
2，3，7，8-四氯二苯并对二恶英（TCDD）是一种典型的卤代芳烃（HAH），被认为是毒性最强的有毒物质之一。其毒性作用的至少一部分似乎来自其诱导TNF-α产生的能力。然而，TCDD导致TNF-α表达的信号通路尚未阐明。在这项研究中，我们研究了TCDD诱导PMA分化的THP-1巨噬细胞表达TNF-α的信号转导机制。TCDD以剂量和时间依赖性方式诱导TNF-α的mRNA和蛋白表达。α-萘啶酮（NF），一种芳香烃受体（AhR）抑制剂，在mRNA和蛋白质水平上阻止TCDD诱导的TNF-α表达。Genistein，一种蛋白酪氨酸激酶（PTK）抑制剂，和PD 153035，一种EGFR抑制剂，也阻断了TCDD引起的TNF-α表达的增加，表明EGFR在TCDD诱导的TNF-α表达中的作用。另一方面，c-Src特异性抑制剂13132不影响TCDD诱导的TNF-α表达。EGFR磷酸化检测早在5分钟后TCDD治疗。TCDD诱导的EGFR激活是AhR依赖性的，因为与α-NF共同处理阻止了它。ERK被发现是TCDD刺激后导致TNF-α产生的信号通路中EGFR激活的下游效应物。TCDD处理后30 min开始观察到ERK的激活。MEK-ERK通路抑制剂PD 98059可完全阻断TCDD诱导的TNF-α mRNA和蛋白表达，而JNK和p38 MAPK抑制剂则无此作用。EGFR抑制剂PD 153035以及α-NF显著降低ERK磷酸化，表明TCDD激活ERK由EGFR和AhR介导。这些结果表明TCDD在分化的THP-1巨噬细胞中产生TNF-α是AhR依赖性的，并且涉及EGFR和ERK的激活，但不涉及c-Src、JNK和p38 MAPK。提出了一种信号通路，其中TCDD诱导AhR、EGFR和ERK的顺序激活，导致TNF-α的表达增加。
2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD), a prototypic halogenated aromatic hydrocarbon (HAH), is known as one of the most potent toxicants. At least a part of its toxic effects appears to be derived from its ability to induce TNF-alpha production. However, the signaling pathway of TCDD that leads to TNF-a expression has not been elucidated. In this study, we investigated the signaling mechanism of TCDD-induced TNF-alpha expression in PMA-differentiated THP-1 macrophages. TCDD induced both mRNA and protein expression of TNF-alpha in a dose- and time-dependent manner. alpha-Naphthoflavone (NF), an aryl hydrocarbon receptor (AhR) inhibitor, prevented the TCDD-induced expression of TNF-alpha at both rnRNA and protein levels. Genistein, a protein tyrosine kinase (PTK) inhibitor, and PD153035, an EGFR inhibitor, also blocked the increase of TNF-alpha expression by TCDD, indicating the role of EGFR in TCDD-induced TNF-alpha expression. On the other hand, 13132, a c-Src specific inhibitor, did not affect TCDD-induced TNF-alpha expression. EGFR phosphorylation was detected as early as 5 min after TCDD treatment. TCDD-induced EGFR activation was AhR-dependent since co-treatment with alpha-NF prevented it. ERK was found to be a downstream effector of EGFR activation in the signaling pathway leading to TNF-alpha production after TCDD stimulation. Activation of ERK was observed from 30 min after TCDD treatment. PD98059, an inhibitor of the MEK-ERK pathway, completely prevented the TNF-alpha mRNA and protein expression induced by TCDD, whereas inhibitors of JNK and p38 MAPK had no effect. PD153035, an EGFR inhibitor, as well as alpha-NF significantly reduced ERK phosphorylation, suggesting that ERK activation by TCDD was mediated by both EGFR and AhR. These results indicate that TNF-alpha production by TCDD in differentiated THP-1 macrophages is AhR-dependent and involves activation of EGFR and ERK, but not c-Src, JNK, nor p38 MAPK. A signaling pathway is proposed where TCDD induces sequential activation of AhR, EGFR and ERK, leading to the increased expression of TNF-a.