Thromboxane A2 promotes interleukin-6 biosynthesis mediated by an activation of cyclic AMP-response element-binding protein in 1321N1 human astrocytoma cells
Thromboxane A2 promotes interleukin-6 biosynthesis mediated by an activation of cyclic AMP-response element-binding protein in 1321N1 human astrocytoma cells
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DOI：
10.1124/mol.105.012922
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发表时间：
2005-09-01
影响因子：
3.6
通讯作者：
Nakahata, N
中科院分区：
文献类型：
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作者：
Obara, Y;Kurose, H;Nakahata, N
1321N1人星形细胞瘤细胞表达血栓素A(2)(TXA(2))受体(TP)。然而，TXA(2)信号在神经胶质细胞中的生理后果仍不清楚。在此，我们证明了TXA(2)促进了神经胶质细胞中白介素6(IL-6)的生物合成。茶多酚激动剂9，11-二脱氧-9α，11α-甲氧基前列腺素-5Z，13E-二烯-1-辛酸(U46619)可促进1321N1细胞和培养的小鼠星形胶质细胞产生IL-6。已有研究表明，IL-6基因表达受多种转录因子的调控。其中，我们发现1321N1细胞中的cAMP反应元件结合蛋白(CREB)活性显著增加，其在Ser133处被U46619磷酸化。虽然U46619增加了IL-6启动子的活性，但启动子上的环状AMP反应元件(CRE)突变明显抑制了这一作用，提示Cre参与了U46619诱导的IL-6的表达。此外，p38丝裂原活化蛋白激酶抑制剂SB203580[4-(4-fluorophenyl)-2-(4-methylsulfinylphenyl)-5-(4-pyridyl)-1H-imidazole]，和蛋白激酶A抑制剂H89[N-[2-(4-溴肉桂氨基)乙基]-5-异喹啉]均抑制CREB和IL-6启动子活性，表明p38MAPK和PKA参与了CREB激活和IL-6表达。为了确定哪些G蛋白参与了U46619诱导的IL-6的合成，用腺病毒方法在1321N1细胞中过表达了Gα(Q)、Gα(12)或Gα(13)的干扰突变体。值得注意的是，Gα(Q)或Gα(13)突变体阻断了U46619产生IL-6。Gα(Q)、Gα(12)或Gα(13)的结构性活性突变体促进IL-6的产生，表明Gα(Q)和Gα(13)参与了U46619诱导的IL-6的产生。综上所述，TXA(2)通过PKA p38MAPK/CREB途径促进1321N1细胞IL-6的生物合成。IL-6的诱导也依赖于Gα(Q)和Gα(13)。这是第一个显示TP介导的IL-6在神经胶质细胞中产生的报告。
1321N1 human astrocytoma cells express thromboxane A(2) (TXA(2)) receptors (TP). However, physiological consequences of TXA(2) signaling in glial cells remain unclear. Herein, we show that TXA(2) promotes interleukin-6 (IL-6) biosynthesis in glial cells. A TP agonist, 9,11-dideoxy-9 alpha, 11 alpha-methanoepoxyprosta-5Z, 13E-dien-1-oic acid (U46619), enhanced IL-6 production in both 1321N1 cells and cultured mouse astrocytes. It has been shown that IL-6 gene expression is regulated by various transcription factors. Among them, we found a significant increase in cyclic AMP-response element-binding protein (CREB) activity with its phosphorylation at Ser133 by U46619 in 1321N1 cells. Although U46619 increased IL-6 promoter activity, a mutation at cyclic AMP-response element (CRE) on the promoter clearly suppressed the effect, suggesting that CRE is involved in U46619-induced IL-6 expression. Furthermore, both CREB and IL-6 promoter activities were suppressed by SB203580 [4-(4-fluorophenyl)-2-(4-methylsulfinylphenyl)-5-(4-pyridyl)-1H-imidazole], a p38 mitogen-activated protein kinase ( MAPK) inhibitor, and H89 [N-[2-(4-bromocinnamylamino)ethyl]-5- isoquinoline], a protein kinase A (PKA) inhibitor, indicating involvements of p38 MAPK and PKA in CREB activation and IL-6 expression. To determine which G-proteins are implicated in the U46619-induced IL-6 synthesis, the interfering mutants of G alpha(q), G alpha(12), or G alpha(13) were overexpressed in 1321N1 cells by adenoviral approach. It is noteworthy that the G alpha(q) or G alpha(13) mutant blocked the IL-6 production by U46619. The constitutively active mutant of G alpha(q), G alpha(12), or G alpha(13) enhanced IL-6 production, indicating that G alpha(q) and G alpha(13) were involved in U46619-induced IL-6 production. In conclusion, TXA(2) enhances the IL-6 biosynthesis via the PKA p38 MAPK/CREB pathway in 1321N1 cells. IL-6 induction depends on G alpha(q) and G alpha(13) as well. This is the first report showing TP-mediated IL-6 production in glial cells.