Lipopolysaccharide activation of the MEK-ERK1/2 pathway in human monocytic cells mediates tissue factor and tumor necrosis factor α expression by inducing Elk-1 phosphorylation and Egr-1 expression
Lipopolysaccharide activation of the MEK-ERK1/2 pathway in human monocytic cells mediates tissue factor and tumor necrosis factor α expression by inducing Elk-1 phosphorylation and Egr-1 expression
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DOI：
10.1182/blood.v98.5.1429
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发表时间：
2001-09-01
期刊：
影响因子：
20.3
通讯作者：
Mackman, N
中科院分区：
文献类型：
--
作者：
Guha, M;O'Connell, MA;Mackman, N
脂多糖（LPS）诱导人单核细胞表达多种促炎介质，包括促凝分子组织因子（TF）和细胞因子肿瘤坏死因子α (tnf - α)。TF和tnf - α基因受多种转录因子调控，包括核因子(NF)-kappaB/Rel蛋白和Egr-1。本研究探讨了MEK-ERK1/2丝裂原活化蛋白激酶（MAPK）通路在lip诱导人单核细胞TF和tnf - α基因表达中的作用。MAPK激酶（MEK）1抑制剂PD98059以剂量依赖的方式降低LPS诱导的TF和tnf - α表达。PD98059不影响LPS诱导的NF-kappaB/Rel蛋白核易位，对LPS诱导的kb依赖性转录影响最小。相反，Ras-Raf1-MEK-ERK（细胞外信号调节激酶）通路的PD98059和显性阴性突变体强烈抑制LPS诱导的Egr-1表达。在动力学实验中，LPS诱导Egr-1表达先于诱导TF表达。此外，TF和tnf - α启动子中Egr-1位点的突变减少了这些促炎基因的表达。结果表明，LPS诱导Egr-1启动子是由3个SRE位点介导的，这些位点结合了一个含有血清反应因子和Elk-1的LPS诱导复合物。LPS刺激瞬时诱导Elk-1磷酸化，并通过MEK-ERK1/2通路增加GAL4-Elk-1TA嵌合蛋白的功能活性。这些数据表明，LPS诱导Egr-1基因表达是最大限度地诱导人单核细胞中tnf - α和TF基因的必要条件。(C) 2001年由美国血液学会出版。
Lipopolysaccharide (LPS) induces human monocytes to express many proinflammatory mediators, including the procoagulant molecule tissue factor (TF) and the cytokine tumor necrosis factor alpha (TNIF-alpha). The TF and TNF-alpha genes are regulated by various transcription factors, including nuclear factor (NF)-kappaB/Rel proteins and Egr-1. In this study, the role of the MEK-ERK1/2 mitogen-activated protein kinase (MAPK) pathway in LIPS induction of TF and TNF-alpha gene expression in human monocytic cells was investigated. The MAPK kinase (MEK)1 inhibitor PD98059 reduced LPS induction of TF and TNIF-alpha expression in a dose-dependent manner. PD98059 did not affect LPS-induced nuclear translocation of NF-kappaB/Rel proteins and minimally affected LPS induction Of KB-dependent transcription. In contrast, PD98059 and dominant-negative mutants of the Ras-Raf1-MEK-ERK (extacellular signal-regulated kinase) pathway strongly inhibited LPS induction of Egr-1 expression. In kinetic experiments LPS induction of Egr-1 expression preceded induction of TF expression. In addition, mutation of the Egr-1 sites in the TF and TNF-alpha promoters reduced expression of these proinflammatory genes. It was demonstrated that LPS induction of the Egr-1 promoter was mediated by 3 SRE sites, which bound an LIPS-Inducible complex containing serum response factor and Elk-1. LPS stimulation transiently induced phosphorylation of Elk-1 and increased the functional activity of a GAL4-Elk-1TA chimeric protein via the MEK-ERK1/2 pathway. The data indicate that LPS induction of Egr-1 gene expression is required for maximal induction of the TNF-alpha and TF genes in human monocytic cells. (C) 2001 by The American Society of Hematology.