Anti-inflammatory cytokine interleukin-4 inhibits inducible nitric oxide synthase gene expression in the mouse macrophage cell line RAW264.7 through the repression of octamer-dependent transcription.
Anti-inflammatory cytokine interleukin-4 inhibits inducible nitric oxide synthase gene expression in the mouse macrophage cell line RAW264.7 through the repression of octamer-dependent transcription.
复制标题
DOI：
10.1155/2013/369693
复制
发表时间：
2013
影响因子：
4.6
通讯作者：
Ohmori Y
中科院分区：
文献类型：
--
作者：
Hiroi M;Sakaeda Y;Yamaguchi H;Ohmori Y
诱导型一氧化氮合酶（Inducible nitric oxide synthase，iNOS）是一种参与M1巨噬细胞经典活化的标志性分子，在Th 1细胞源性干扰素γ（interferon-gamma，IFNγ）和细菌脂多糖（lipopolysaccharide，LPS）刺激下由Nos 2基因诱导产生。虽然已知抗炎细胞因子IL-4抑制Nos 2基因表达，但IL-4对Nos 2负调控的分子机制仍有待充分阐明。在本研究中，我们研究了IL-4介导的小鼠巨噬细胞样细胞系RAW 264.7中Nos 2转录抑制的机制。siRNA干扰信号转导子和转录激活子6（Stat 6）后，IFNγ/LPS诱导的IL-4对Nos 2的抑制作用消失。瞬时转染含有Nos 2基因5′侧翼区的荧光素酶报告基因表明，启动子区的八聚体转录因子（OCT）结合位点是IFNγ/LPS正调控和IL-4负调控所必需的。虽然IL-4对组成型表达的Oct-1的DNA结合活性没有抑制作用，但IL-4诱导的Nos 2报告转录抑制通过共激活因子CREB结合蛋白（CBP）的过表达而部分减弱。这些结果表明，与Oct-1功能性相互作用的辅激活因子/辅因子是IL-4介导的Nos 2抑制的分子靶标，并且IL-4激活的Stat 6通过与该辅激活因子/辅因子竞争来抑制Oct-1依赖性转录。
Inducible nitric oxide synthase (iNOS) is a signature molecule involved in the classical activation of M1 macrophages and is induced by the Nos2 gene upon stimulation with Th1-cell derived interferon-gamma (IFNγ) and bacterial lipopolysaccharide (LPS). Although the anti-inflammatory cytokine IL-4 is known to inhibit Nos2 gene expression, the molecular mechanism involved in the negative regulation of Nos2 by IL-4 remains to be fully elucidated. In the present study, we investigated the mechanism of IL-4-mediated Nos2 transcriptional repression in the mouse macrophage-like cell line RAW264.7. Signal transducer and activator of transcription 6 (Stat6) knockdown by siRNA abolished the IL-4-mediated inhibition of Nos2 induced by IFNγ/LPS. Transient transfection of a luciferase reporter gene containing the 5′-flanking region of the Nos2 gene demonstrated that an octamer transcription factor (OCT) binding site in the promoter region is required for both positive regulation by IFNγ/LPS and negative regulation by IL-4. Although IL-4 had no inhibitory effect on the DNA-binding activity of constitutively expressed Oct-1, IL-4-induced Nos2-reporter transcriptional repression was partially attenuated by overexpression of the coactivator CREB-binding protein (CBP). These results suggest that a coactivator/cofactor that functionally interacts with Oct-1 is a molecular target for the IL-4-mediated inhibition of Nos2 and that IL-4-activated Stat6 represses Oct-1-dependent transcription by competing with this coactivator/cofactor.
登录
查看更多内容
影响因子：
5.5
作者：
BOGDAN, C;VODOVOTZ, Y;NATHAN, C
通讯作者：
NATHAN, C
影响因子：
4.4
作者：
Deng, WG;Wu, KK
通讯作者：
Wu, KK
影响因子：
64.5
作者：
Kamei, Y;Xu, L;Rosenfeld, MG
通讯作者：
Rosenfeld, MG
影响因子：
32.4
作者：
Kaplan, MH;Schindler, U;Grusby, MJ
通讯作者：
Grusby, MJ
影响因子：
56.9
作者：
KOTANIDES, H;REICH, NC
通讯作者：
REICH, NC