Synergistic expression of inducible nitric oxide synthase by phorbol ester and interferon-γ is mediated through NF-κB and ERK in microglial cells
Synergistic expression of inducible nitric oxide synthase by phorbol ester and interferon-γ is mediated through NF-κB and ERK in microglial cells
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DOI：
10.1002/jnr.10706
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发表时间：
2003-09-01
影响因子：
4.2
通讯作者：
Kim, WK
中科院分区：
文献类型：
--
作者：
Han, IO;Kim, HS;Kim, WK
促炎细胞因子干扰素-γ刺激损伤脑内的小胶质细胞；然而，干扰素-γ介导的小胶质细胞激活的信号通路尚未得到很好的描述。在本研究中，蛋白激酶C(PKC)激活剂佛波醇12-肉豆蔻酸盐13-乙酸酯(PMA)与干扰素-γ协同作用，通过协同增加诱导型一氧化氮合酶(INOS)的表达来增加小鼠小胶质细胞BV2细胞中一氧化氮(NO)的产生。PKC抑制剂Go6976部分抑制了PMA协同产生NO的作用。PMA单独诱导核因子-kappaB(NF-kappaB)和细胞外信号调节激酶(ERK)激活丝裂原活化蛋白激酶(MAPKs)亚型，而干扰素-γ单独作用不明显。PMA和干扰素-γ协同增强了NF-kappaB的活性，但不能增强ERK的活性。NF-kappaB(吡咯烷二硫代氨基甲酸酯，PDTC)和ERK(1，4-二氨基-2，3-二氰基-1，4-二[2-氨基苯硫基]丁二烯；U0126)抑制剂可显著降低干扰素-γ和PMA联合作用下BV2细胞中NO的产生。我们进一步发现，干扰素-γ和PMA协同诱导干扰素调节因子-1(IRF-1)，它是干扰素-γ介导的一氧化氮合酶表达的主要转录因子。本研究结果证实了多种信号通路在诱导激活的小胶质细胞产生NO中的协同作用，并提示这些信号通路的功能相互作用可能在脑内小胶质细胞介导的炎症反应的发生中起重要作用。(C)Wiley-Liss公司
A proinflammatory cytokine IFN-gamma stimulates microglia in the injured brain; however, signaling pathways for IFN-gamma-mediated microglia activation are not well characterized. In the present study, a protein kinase C (PKC) activator phorbol 12-myristate 13-acetate (PMA) acts in concert with IFN-gamma to enhance nitric oxide (NO) production in murine microglial BV2 cells by synergistically increasing expression of inducible NO synthase (iNOS). The synergistic NO production by PMA was in part decreased by a PKC inhibitor Go6976. PMA alone induced activation of nuclear factor-kappa B (NF-kappaB) and extracellular signal-regulated kinase (ERK) of mitogen-activated protein kinases (MAPKs) subtypes, whereas IFN-gamma alone had little effect. PMA and IFN-gamma synergistically enhanced activity of NF-kappaB, but not ERK. The inhibitors of NF-kappaB (pyrrolidine dithiocarbamate, PDTC) and ERK (1,4-diamino-2,3-dicyano-1,4 bis[2-aminophenylthio]butadiene; U0126) markedly decreased synergistic NO production in BV2 cells treated with IFN-gamma and PMA in combination. We found further that co-treatment with IFN-gamma and PMA synergistically induced interferon regulatory factor-1 (IRF-1), which is the major transcription factor for IFN-gamma-mediated NOS expression. The present results demonstrate the cooperative interaction of multiple signaling pathways in the induction of NO production in activated microglial cells, and suggest that the functional interplay of these pathways may be important for the onset of microglia-mediated inflammatory responses in brain. (C) Wiley-Liss, Inc.