On the role of c-Jun in the induction of PAI-1 gene expression by phorbol ester, serum, and IL-1α in HepG2 cells
On the role of c-Jun in the induction of PAI-1 gene expression by phorbol ester, serum, and IL-1α in HepG2 cells
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DOI：
10.1161/01.atv.19.1.39
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发表时间：
1999-01-01
影响因子：
8.7
通讯作者：
Kooistra, T
中科院分区：
文献类型：
--
作者：
Arts, J;Grimbergen, J;Kooistra, T
我们的特点是调节纤溶酶原激活物抑制剂-1（派-1）基因表达佛波酯12-肉豆蔻酸酯13-乙酸酯（PMA），血清，白细胞介素-1 α（IL-1 α）在人肝癌细胞系HepG 2。PMA、血清和IL-1 α诱导派-1 mRNA快速和短暂增加28倍（PMA）、9倍（血清）和23倍（IL-1 α），约4小时后达到峰值。用蛋白酪氨酸激酶抑制剂genistein预处理HepG 2细胞可降低派-1 mRNA的表达。相反，刺激酪氨酸磷酸化的原钒酸钠，蛋白酪氨酸磷酸酶的抑制剂，引起派-1 mRNA水平的增加。PMA、血清和IL-1 α对派-1 mRNA表达的影响与它们调节氯霉素乙酰转移酶（CAT）报告质粒表达的能力进行了比较，该报告质粒在派-1启动子的-489至+75区域的控制下，并稳定转染到HepG 2细胞中。以前发现派-1启动子的这个区域含有PMA反应性所必需的十四酰基佛波醇乙酸酯反应元件（TRE;在-58和-50之间），并且对c-Jun同源二聚体具有高亲和力。然而，这些转染的HepG 2细胞与PMA和血清孵育显示CAT mRNA的诱导谱与PAT-I mRNA的诱导谱相似，几乎没有发现IL-1 α对CAT mRNA的诱导。与这些发现一致，在凝胶迁移率变化测定中，IL-1 α诱导c-Jun同二聚体与PAI-1 TRE的结合较差。用蛋白激酶C抑制剂Ro 31-8220或丝裂原活化蛋白激酶激酶（MAPKK）（1，2）活性阻断剂PD 98059预处理HepG 2细胞，可选择性抑制PMA诱导的派-1（和CAT）表达，但对IL-1a的诱导无明显影响。相反，蛋白酪氨酸激酶抑制剂除莠霉素A仅阻断IL-1 α对PAI-T mRNA的诱导。我们提出了2个单独的PAI-1诱导途径PMA和LL-1 α在HepG 2，都涉及蛋白酪氨酸激酶激活;血清诱导的信号通路可能（部分）与PMA激活的蛋白激酶C/丝裂原激活的蛋白激酶激酶途径重叠，导致c-Jun同源二聚体结合派-1 TRE。
We have characterized the regulation of plasminogen activator inhibitor-1 (PAI-1) gene expression by phorbol 12-myristate 13-acetate (PMA), serum, and interleukin-1 alpha (IL-1 alpha) in the human hepatoma cell Line HepG2. PMA, serum, and IL-1 alpha induced a rapid and transient 28-fold (PMA), 9-fold (serum), and 23-fold (IL-1 alpha) increase in PAI-1 mRNA, peaking after approximate to 4 hours. These inductions of PAI-1 mRNA accumulation were reduced by pretreatment of the HepG2 cells with the protein tyrosine kinase inhibitor genistein. Conversely, stimulation of tyrosine phosphorylation by sodium orthovanadate, an inhibitor of protein tyrosine phosphatases, caused an increase in PAI-1 mRNA levels. The effects of PMA, serum, and IL-1 alpha on PAI-1 mRNA expression have been compared with their ability to modulate the expression of a chloramphenicol acetyltransferase (CAT) reporter plasmid, which was under control of the -489 to +75 region of the PAI-1 promoter, and stably transfected into HepG2 cells. This region of the PAI-1 promoter was previously found to contain a tetradecanoyl phorbol acetate-response element (TRE; between -58 and -50) necessary for PMA responsiveness and with a high affinity for c-Jun homodimers. Whereas incubation of these transfected HepG2 cells with PMA and serum showed an induction profile of CAT mRNA similar to that of PAT-I mRNA, hardly any induction of CAT mRNA was found with IL-1 alpha. In line with these findings, IL-1 alpha poorly induced c-Jun homodimer binding to the PAI-I TRE in gel mobility-shift assays. Pretreatment of HepG2 cells with the protein kinase C inhibitor Ro 31-8220 or the mitogen-activated protein kinase kinase (MAPKK)(1,2) activity blocker PD98059 selectively suppressed the induction of PAI-1 (and CAT) expression by PMA, but not that by IL-la. In contrast, the protein tyrosine kinase inhibitor herbimycin A blocked PAI-T mRNA induction by IL-1 alpha only. We propose 2 separate PAI-I inductory pathways for PMA and LL-1 alpha in HepG2, both involving protein tyrosine kinase activation; the serum-induced signaling pathway may (partially) overlap with the PMA-activated protein kinase C/mitogen-activated protein kinase kinase pathway, leading to c-Jun homodimer binding to the PAI-1 TRE.