Maita Chinatsu, Matsushita Mizue, Miyoshi Masahiro, Okubo Torahiko, Nakamura Shinji, Matsuo Junji, Takemura Masaharu, Miyake Masaki, Nagai Hiroki, Yamaguchi Hiroyuki
Department of Medical Laboratory Science, Faculty of Health Sciences, Hokkaido University, North-12, West-5, Kita-ku, Sapporo, 060-0812, Japan.
Division of Biomedical Imaging Research, Juntendo University Graduate School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan.
Microbes Infect. 2018 Apr;20(4):236-244. doi: 10.1016/j.micinf.2017.12.012. Epub 2018 Jan 6.
Acanthamoeba isolated from environmental soil harbors the obligate intracellular symbiont Neochlamydia, which has a critical role in host amoebal defense against Legionella pneumophila infection. Here, by using morphological analysis with confocal laser scanning fluorescence microscopy and transmission electron microscopy, proteome analyses with two-dimensional fluorescence difference gel electrophoresis (2D-DIGE) and liquid chromatography-mass spectrometry (LC/MS), and transcriptome analysis with DNA microarray, we explored the mechanism by which the Neochlamydia affected this defense. We observed that when rare uptake did occur, the symbiotic amoebae allowed Legionella to grow normally. However, the symbiotic amoebae had severely reduced uptake of Legionella when compared with the aposymbiotic amoebae. Also, in contrast to amoebae carrying the endosymbiont, the actin cytoskeleton was significantly disrupted by Legionella infection in aposymbiotic amoebae. Furthermore, despite Legionella exposure, there was little change in Neochlamydia gene expression. Taken together, we concluded that the endosymbiont, Neochlamydia prevents Legionella entry to the host amoeba, resulting in the host defense against Legionella infection.
从环境土壤中分离出的棘阿米巴携带专性细胞内共生菌新衣原体，新衣原体在宿主变形虫抵御嗜肺军团菌感染中起关键作用。在此，我们通过共聚焦激光扫描荧光显微镜和透射电子显微镜进行形态学分析、利用二维荧光差异凝胶电泳（2D-DIGE）和液相色谱-质谱联用（LC/MS）进行蛋白质组分析以及运用DNA微阵列进行转录组分析，探究了新衣原体影响这种防御作用的机制。我们观察到，当确实发生罕见的摄取时，共生变形虫会让军团菌正常生长。然而，与无共生变形虫相比，共生变形虫对军团菌的摄取显著减少。此外，与携带内共生菌的变形虫不同，在无共生变形虫中，军团菌感染会使肌动蛋白细胞骨架明显受到破坏。此外，尽管暴露于军团菌，但新衣原体的基因表达几乎没有变化。综上所述，我们得出结论，内共生菌新衣原体可阻止军团菌进入宿主变形虫，从而实现宿主对军团菌感染的防御。
