Transforming growth factor-β1 induces interleukin-6 expression via activating protein-1 consisting of JunD homodimers in primary human lung fibroblasts
Transforming growth factor-β1 induces interleukin-6 expression via activating protein-1 consisting of JunD homodimers in primary human lung fibroblasts
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DOI：
10.1074/jbc.274.18.12933
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发表时间：
1999-04-30
影响因子：
4.8
通讯作者：
Roth, M
中科院分区：
文献类型：
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作者：
Eickelberg, O;Pansky, A;Roth, M
转化生长因子-β1诱导细胞外基质沉积和间充质细胞增殖。我们最近报道，白介素6是生长因子诱导的肺成纤维细胞增殖的重要介质。在这里，我们通过逆转录聚合酶链式反应和酶联免疫分析证明，转化生长因子-β1是原代人肺成纤维细胞中IL-6mRNA和蛋白的有效诱导者。瞬时将含有人IL-6启动子-651到+1核苷酸的荧光素酶报告基因结构导入成纤维细胞，结果表明转化生长因子-β1也有效地激活了IL-6启动子的活性。亲本结构的渐进性5‘-缺失和定点突变定位于已知激活蛋白-1(AP-1)序列(核苷酸-284至-276)的转化生长因子-β1反应顺式调控元件。凝胶位移分析显示，经转化生长因子-β1刺激30分钟后，核提取液中AP-1 DNA结合活性增强。而CCAAT增强子结合蛋白-β、核因子-kappaB和SPL均未被转化生长因子-β1激活。SuperShift分析表明，转化生长因子-β1诱导的AP-1复合体由Jun异构体组成，不存在Fos异构体，而且该复合体是一种Jund同源二聚体。我们的结果表明，在原代培养的人肺成纤维细胞中，转化生长因子-β1对IL-6具有很强的诱导性。转化生长因子-β1激活的Jund同源二聚体可能是转化生长因子-β1在该类型细胞中诱导的大部分生物学效应所必需的，如增殖和细胞外基质合成。
Transforming growth factor (TGF)-beta 1 induces extracellular matrix deposition and proliferation of mesenchymal cells. We recently reported that interleukin (IL)-6 is an essential mediator of growth factor-induced proliferation of lung fibroblasts. Here, we demonstrate by reverse transcriptase polymerase chain reaction and enzyme-linked immunoassay that TGF-beta 1 is a potent inducer of IL-6 mRNA and protein in primary human lung fibroblasts, Transient transfections of fibroblasts with a luciferase reporter gene construct containing nucleotides -651 to +1 of the human IL-6 promoter revealed that TGF-beta 1 also potently activated IL-6 promoter activity. Progressive 5'-deletions and site-directed mutagenesis of the parental construct located the TGF-pl-responsive cis-regulatory element to a known activating protein-1 (AP-1) sequence (nucleotides -284 to -276). Gel shift analyses revealed that AP-1 DNA binding activity in nuclear extracts was increased 30 min after stimulation with TGF-beta 1. In contrast, neither CCAAT enhancer-binding protein-beta, NF-kappa B, nor Spl were activated by TGF-beta 1, Supershift analyses demonstrated that the AP-1 complex induced by TGF-beta 1 was composed of Jun isoforms and absent of Fos isoforms, Moreover, this complex was found to be a JunD homodimer, Our data thus demonstrate that TGF-beta 1 is a potent inducer of IL-6 in primary human lung fibroblasts, The TGF-beta 1-activated JunD homodimer may be essential for a majority of the biological effects induced by TGF-beta 1 in this cell type, such as proliferation and extracellular matrix synthesis.