Yersinia pestis Requires Host Rab1b for Survival in Macrophages.
Yersinia pestis Requires Host Rab1b for Survival in Macrophages.
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DOI：
10.1371/journal.ppat.1005241
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发表时间：
2015-10
期刊：
影响因子：
6.7
通讯作者：
Lawrenz MB
中科院分区：
文献类型：
--
作者：
Connor MG;Pulsifer AR;Price CT;Abu Kwaik Y;Lawrenz MB
鼠疫耶尔森氏菌是一种兼性的细胞内病原体，会导致这种被称为鼠疫的疾病。在感染巨噬细胞期间，鼠疫杆菌主动避开正常的吞噬小体成熟途径，在细胞内建立一个复制的生态位。然而，鼠疫杆菌用来破坏巨噬细胞杀伤的机制尚不清楚。宿主Rab GTP酶是囊泡运输的中心媒介，通常是细菌病原体的靶标，改变吞噬小体的成熟和被巨噬细胞杀死。在这里，我们首次证明宿主Rab1b是鼠疫杆菌有效逃避巨噬细胞杀伤所必需的。我们还发现Rab1b被特异性地招募到含有耶尔森氏菌的空泡(YCV)中，当Rab1b在巨噬细胞中的表达被下调时，鼠疫耶尔森菌不能破坏YCV的酸化。此外，Rab1b基因敲除还改变了YCV与溶酶体标记LAMP1之间的联系频率，表明Rab1b募集到YCV直接抑制吞噬小体成熟。最后，我们证明了Rab1b基因敲除也影响了含有液泡的嗜肺军团菌的pH值，液泡是另一种将Rab1b招募到其液泡中的病原体。综上所述，这些数据确定了Rab1b在细胞内病原体颠覆吞噬小体成熟过程中的一个新角色，并表明Rab1b对含有液泡的病原体的募集可能是控制液泡pH的一种保守机制。鼠疫耶尔森氏菌是导致人类疾病鼠疫的细菌剂。虽然通常被认为是一种历史性的疾病，但鼠疫在几个大陆的啮齿动物种群中是地方性的，世界卫生组织认为鼠疫是一种新出现的疾病。这种病原体的成功很大程度上来自于它逃避宿主天然免疫系统清除的能力。鼠疫杆菌武器库中的一种武器是它被巨噬细胞吞噬时抵抗死亡的能力。在入侵巨噬细胞时，鼠疫杆菌主动操纵细胞产生一个保护性的空泡室，称为含有耶尔森氏菌的空泡(YCV)，使细菌能够逃避巨噬细胞的正常病原体杀伤机制。在这里，我们证明了宿主蛋白Rab1b被招募到YCV中，并且是鼠疫杆菌抑制吞噬小体的酸化和正常成熟以建立细胞内保护生态位所必需的。Rab1b是第一个被证明对YCV的生物发生有贡献的蛋白质，无论是来自宿主还是来自鼠疫杆菌。此外，我们的数据表明，在吞噬小体成熟途径中，Rab1b的募集存在一种以前未知的影响。
Yersinia pestis is a facultative intracellular pathogen that causes the disease known as plague. During infection of macrophages Y. pestis actively evades the normal phagosomal maturation pathway to establish a replicative niche within the cell. However, the mechanisms used by Y. pestis to subvert killing by the macrophage are unknown. Host Rab GTPases are central mediators of vesicular trafficking and are commonly targeted by bacterial pathogens to alter phagosome maturation and killing by macrophages. Here we demonstrate for the first time that host Rab1b is required for Y. pestis to effectively evade killing by macrophages. We also show that Rab1b is specifically recruited to the Yersinia containing vacuole (YCV) and that Y. pestis is unable to subvert YCV acidification when Rab1b expression is knocked down in macrophages. Furthermore, Rab1b knockdown also altered the frequency of association between the YCV with the lysosomal marker Lamp1, suggesting that Rab1b recruitment to the YCV directly inhibits phagosome maturation. Finally, we show that Rab1b knockdown also impacts the pH of the Legionella pneumophila containing vacuole, another pathogen that recruits Rab1b to its vacuole. Together these data identify a novel role for Rab1b in the subversion of phagosome maturation by intracellular pathogens and suggest that recruitment of Rab1b to the pathogen containing vacuole may be a conserved mechanism to control vacuole pH. Yersinia pestis is the bacterial agent that causes the human disease known as plague. While often considered a historic disease, Y. pestis is endemic in rodent populations on several continents and the World Health Organization considers plague to be a reemerging disease. Much of the success of this pathogen comes from its ability to evade clearance by the innate immune system of its host. One weapon in the Y. pestis arsenal is its ability to resist killing when engulfed by macrophages. Upon invasion of macrophages, Y. pestis actively manipulates the cell to generate a protective vacuolar compartment, called the Yersinia containing vacuole (YCV) that allows the bacterium to evade the normal pathogen killing mechanisms of the macrophage. Here we demonstrate that the host protein Rab1b is recruited to the YCV and is required for Y. pestis to inhibit both the acidification and normal maturation of the phagosome to establish a protective niche within the cell. Rab1b is the first protein, either from the host or Y. pestis, shown to contribute to the biogenesis of the YCV. Furthermore, our data suggest a previously unknown impact of Rab1b recruitment in the phagosome maturation pathway.