p38 MAPK-mediated transcriptional activation of inducible nitric-oxide synthase in glial cells -: Roles of nuclear factors, nuclear factor κB, cAMP response element-binding protein, ccaat/enhancer-binding protein-β, and activating transcription factor-2
p38 MAPK-mediated transcriptional activation of inducible nitric-oxide synthase in glial cells -: Roles of nuclear factors, nuclear factor κB, cAMP response element-binding protein, ccaat/enhancer-binding protein-β, and activating transcription factor-2
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DOI：
10.1074/jbc.m204994200
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发表时间：
2002-08-16
影响因子：
4.8
通讯作者：
Bhat, AN
中科院分区：
文献类型：
--
作者：
Bhat, NR;Feinstein, DL;Bhat, AN
先前的研究表明，丝裂原激活蛋白激酶 (MAPK) 级联信号可诱导神经胶质细胞中诱导型一氧化氮合酶 (iNOS) 的诱导（Bhat, N. R.、Zhang, P.、Lee, J. C. 和 Hogan E. L. (1998) J. Neurosci. 18, 1633-1641；Bhat, N. R.、Zhang, P. 和 Bhat, A. N. (1999) J. Neurochem。 72,472-478）。本研究通过瞬时转染通路中组成型活性上游激酶（即 MAPK 激酶 3 (MKK3b(E)) 和 MAPK 激酶 6 (MKK6b(E)），进一步研究 p38 MAPK 在 iNOS 基因转录激活中的作用。MKK3b(E) 或 MKK6b(E) 在 C-6 胶质细胞中的表达导致 诱导共转染的大鼠 iNOS 启动子-报告基因（iNOS-荧光素酶 (Luc)）基因的活性，并增强细胞因子诱导的 iNOS mRNA 表达，这两者均可被 p38 MAPK 抑制剂 SB203580 抑制。 MKK 构建体还诱导 CAMP 反应元件介导 (CRE-Luc) 和核因子 kappaB 依赖性（核因子 kappaB-Luc)转录活性。 p38 MAPK 通路靶向的两种 CRE 结合转录因子，显性失活 (dn) 形式的 CRE 结合蛋白 (CREB) 和 CCAAT/增强子结合蛋白 (C/EBP) 转染会产生相反的效果。 dnCREB 增强和 dnC/EBP 抑制 iNOS-Luc，与它们对 CRE-Luc 的作用平行。在 此外，野生型激活转录因子（ATF-2）增强了MKK3b（E）和MKK6b（E）对iNOS启动子活性的诱导，而磷酸化缺陷形式的ATF-2则具有抑制作用。这些分子研究的结果提供了 p38 MAPK 通路在大鼠神经胶质细胞 iNOS 基因转录激活中的重要作用的证据，其中涉及 转录因子核因子 kappaB、C/EBP 和 ATF-2。
Previous studies have shown that mitogen-activated protein kinase (MAPK) cascades signal the induction of inducible nitric-oxide synthase (iNOS) in glial cells (Bhat, N. R., Zhang, P., Lee, J. C., and Hogan E. L. (1998) J. Neurosci. 18, 1633-1641; Bhat, N. R., Zhang, P., and Bhat, A. N. (1999) J. Neurochem. 72,472-478). This study further investigates the role of p38 MAPK in the transcriptional activation of the iNOS gene by transient transfection with constitutively active upstream kinases in the pathway (i.e. MAPK kinase 3 (MKK3b(E)) and MAPK kinase 6 (MKK6b(E)). Expression in C-6 glial cells of either MKK3b(E) or MKK6b(E) resulted in an induction of the activity of a cotransfected rat iNOS promoter-reporter (iNOS-luciferase (Luc)) gene and an enhancement of cytokine-induced expression of iNOS mRNA, both of which were inhibitable by the p38 MAPK inhibitor SB203580. The MKK constructs also induced CAMP response element-mediated (CRE-Luc) and nuclear factor kappaB-dependent (nuclear factor kappaB-Luc) transcriptional activities. Transfection with dominant negative (dn) forms of CRE-binding protein (CREB) and CCAAT/enhancer-binding protein (C/EBP), the two CRE-binding transcription factors targeted by the p38 MAPK pathway, resulted in opposite effects; dnCREB enhanced and dnC/EBP inhibited iNOS-Luc parallel to their effects on CRE-Luc. In addition, the induction, by MKK3b(E) and MKK6b(E), of iNOS promoter activity was enhanced by a wild-type activating transcription factor (ATF-2), whereas a phosphorylation-defective form of ATF-2 had a suppressive effect. The results of these molecular studies provide evidence for an important role for the p38 MAPK pathway in the transcriptional activation of the iNOS gene in rat glial cells involving the transcription factors nuclear factor kappaB, C/EBP, and ATF-2.