• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Life sciences >Nitric oxide synthesis and TNF-alpha secretion in RAW 264.7 macrophages - Mode of action of a fermented papaya preparation
【24h】

Nitric oxide synthesis and TNF-alpha secretion in RAW 264.7 macrophages - Mode of action of a fermented papaya preparation

机译：RAW 264.7巨噬细胞中一氧化氮的合成和TNF-α的分泌-木瓜发酵液的作用方式

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Macrophage inducible nitric oxide synthase is able to generate massive amounts of nitric oxide (NO) which contributes to the host immune defense against viruses and bacteria. Monocyte-macrophages stimulated with the bacterial wall component lipopolysaccharide (LPS) and cytokines such as interferon-gamma (IFN-gamma) express the inducible form of nitric oxide synthase (iNOS). Furthermore, tumor necrosis factor-alpha (TNF-alpha) is one of the central regulatory cytokines in macrophage antimicrobial activity and synergizes with IFN-gamma in the induction of NO synthesis. Because of its pivotal role in both antimicrobial and tumoricidal activities of macrophages, a significant effort has focused on developing therapeutic agents that regulate NO production. In the present study fermented papaya preparation (FPP) is shown to exert both immunomodulatory and antioxidant activity in the macrophage cell line RAW 264.7. Interestingly, a low and a high molecular weight fraction (LMF and HMF, respectively) of FPP exhibited different activity patterns. FPP fractions alone did not affect NO production, However in the presence of IFN-gamma, both LMF and HMF significantly increased iNOS activity and nitrite as well as nitrate accumulation. NO radical formation measured in real-time by electron paramagnetic resonance spectroscopy was higher in the presence of LMF and IFN-gamma. On the contrary, iNOS mRNA levels were enhanced further with HMF than with LMF Moreover, LMF displayed a stronger superoxide anion scavenging activity than HMF. In the presence of IFN-gamma, both FPP fractions stimulated TNF-alpha secretion. However in non-stimulated macrophages, TNF-alpha secretion was enhanced by HMF only. Since water-soluble FPP fractions contained no lipid A, present data indicate that FPP is a macrophage activator which augments nitric oxide synthesis and TNF-alpha secretion independently of lipopolysaccharides. (C) 2000 Elsevier Science Inc. All rights reserved. [References: 51]
机译：巨噬细胞诱导型一氧化氮合酶能够产生大量的一氧化氮（NO），有助于宿主对病毒和细菌的免疫防御。用细菌壁成分脂多糖（LPS）和细胞因子（例如干扰素-γ）（IFN-γ）刺激的单核巨噬细胞表达了可诱导形式的一氧化氮合酶（iNOS）。此外，肿瘤坏死因子-α（TNF-α）是巨噬细胞抗菌活性中的主要调节细胞因子之一，并在诱导NO合成中与IFN-γ协同作用。由于其在巨噬细胞的抗微生物和杀肿瘤活性中都起着关键作用，因此，大量的努力集中在开发调节NO产生的治疗剂上。在本研究中，发酵木瓜制品（FPP）在巨噬细胞系RAW 264.7中发挥免疫调节和抗氧化活性。有趣的是，FPP的低分子量部分和高分子量部分（分别为LMF和HMF）表现出不同的活性模式。单独的FPP馏分不会影响NO的产生。但是，在存在IFN-γ的情况下，LMF和HMF均会显着提高iNOS活性，亚硝酸盐以及硝酸盐的积累。在存在LMF和IFN-γ的情况下，通过电子顺磁共振波谱实时测量的NO自由基形成较高。相反，HMF比LMF进一步提高了iNOS mRNA的水平。此外，LMF显示出比HMF更强的超氧阴离子清除活性。在IFN-γ存在下，两个FPP组分均刺激TNF-α分泌。但是，在非刺激的巨噬细胞中，TNF-α分泌仅通过HMF增强。由于水溶性FPP馏分不含脂质A，因此现有数据表明FPP是巨噬细胞活化剂，可独立于脂多糖而增加一氧化氮的合成和TNF-α的分泌。 （C）2000 Elsevier Science Inc.保留所有权利。 [参考：51]

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号