Involvement of reactive oxygen intermediate in the enhanced expression of virulence-associated genes of Listeria monocytogenes inside activated macrophages
Involvement of reactive oxygen intermediate in the enhanced expression of virulence-associated genes of Listeria monocytogenes inside activated macrophages
复制标题
DOI：
10.1111/j.1348-0421.2005.tb03661.x
复制
发表时间：
2005-01-01
影响因子：
2.6
通讯作者：
Mitsuyama, M
中科院分区：
文献类型：
--
作者：
Makino, M;Kawai, M;Mitsuyama, M
李斯特菌溶血素0（Listeriolysin 0）是单核细胞增多性李斯特菌（Listeria monocytogenes）的主要毒力因子，由1，587 bp的hly基因编码，能从巨噬细胞的吞噬体中逃逸后在胞浆内复制。通过使用具有或不具有IFN-γ加LPS活化的小鼠巨噬细胞样J774.1细胞，通过RT-PCR监测hly及其正调节因子prfA的表达。在活化的J774.1细胞中，hly表达水平增强，但细菌的增殖被显著抑制。激活的巨噬细胞内的hly的表达升高被取消，通过添加SOD和过氧化氢酶，表明活性氧中间体有助于prfA和hly transparency的上调。此外，我们发现，暴露的单核细胞增生李斯特菌H2 O2显着增强的表达prfA和hly的mRNA。自发ONOO-发生器SIN-1也能促进转录到一定水平.这些结果表明，在活化的巨噬细胞产生的氧自由基提供了一个积极的信号，上调单核细胞增生李斯特菌的毒力基因。
Listeriolysin 0 encoded by 1,587 bp hly is the essential virulence factor of Listeria monocytogenes that replicates in the cytosolic space after escaping from phagosome of macrophages. By using murine macrophage-like J774.1 cells with or without activation by IFN-gamma plus LPS, the expression of both hly and its positive regulator prfA was monitored by means of RT-PCR. In activated J774.1 cells, the level of hly expression was enhanced although the multiplication of bacteria was significantly suppressed. The elevated expression of hly inside activated macrophage was abolished by addition of SOD and catalase, suggesting that reactive oxygen intermediates contribute to the upregulation of prfA and hly transcriptions. Moreover, we found that exposure of L monocytogenes to H2O2 dramatically enhanced the expression of both prfA and hly mRNAs. Spontaneous ONOO- generator, SIN-1, also promoted the transcription to a certain level. These results suggested that oxygen radicals generated in activated macrophages provide a positive signal for up-regulation of virulence genes in L monocytogenes.