Intracellular trafficking of Brucella abortus in J774 macrophages
Intracellular trafficking of Brucella abortus in J774 macrophages
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DOI：
10.1128/iai.68.7.4255-4263.2000
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发表时间：
2000-07-01
影响因子：
3.1
通讯作者：
Mayorga, LS
中科院分区：
文献类型：
--
作者：
Arenas, GN;Staskevich, AS;Mayorga, LS
流产布鲁氏菌是一种兼性胞内细菌，能够在专职和非专职吞噬细胞内存活。微生物保留在膜结合区室中，在几种细胞类型中类似于修饰的内质网结构。为了监测B种布氏杆菌在巨噬细胞内的转运，用电镜观察了巨噬细胞吞噬体与预先形成的胶体金标记溶酶体融合的动力学。流产儿不愿与溶酶体接触。此外，新的内吞物质没有纳入这些吞噬体。这些观察结果表明，细菌强烈影响巨噬细胞吞噬体的正常成熟过程，然而，过夜孵育后，在含有金颗粒的大吞噬体中发现了显著百分比的微生物，类似于吞噬溶酶体。大多数存在于吞噬溶酶体中的布鲁氏菌细菌在形态上没有改变，这表明它们也可以抵抗该隔室中普遍存在的恶劣条件。观察到约50%的流产B菌与LysoSensor（一种在酸性隔室中积累的弱碱）共定位，表明流产B菌不能阻止吞噬体酸化。与已经描述的HeLa细胞相反，在用自噬体的标记物单丹酰尸胺和DiOC 6标记的隔室中仅发现了小百分比的微生物。这些结果表明，B，流产细菌改变巨噬细胞中吞噬体的成熟，然而，酸化确实发生在这些吞噬体中，其中一些最终可以成熟为吞噬溶酶体。
Brucella abortus is a facultative intracellular bacterium capable of surviving inside professional and nonprofessional phagocytes. The microorganism remains in membrane-bound compartments that in several cell types resemble modified endoplasmic reticulum structures. To monitor the intracellular transport of B, abortus in macrophages, the kinetics of fusion of phagosomes with preformed lysosomes labeled with colloidal gold particles was observed by electron microscopy, The results indicated that phagosomes containing live B. abortus were reluctant to Fuse with lysosomes. Furthermore, newly endocytosed material was not incorporated into these phagosomes. These observations indicate that the bacteria strongly affect the normal maturation process of macrophage phagosomes, However, after overnight incubation, a significant percentage of the microorganisms were found in large phagosomes containing gold particles, resembling phagolysosomes. Most of the Brucella bacteria present in phagolysosomes were not morphologically altered, suggesting that they can also resist the harsh conditions prevalent in this compartment. About 50% colocalization of B, abortus with LysoSensor, a weak base that accumulates in acidic compartments, was observed, indicating that the B, abortus bacteria do not prevent phagosome acidification. In contrast to what has been described for HeLa cells, only a minor percentage of the microorganisms were found in compartments Labeled with monodansylcadaverine, a marker for autophagosomes, and with DiOC6 (3,3'-dihexyloxacarbocyanine iodide), a marker for the endoplasmic reticulum, These results indicate that B, abortus bacteria alter phagosome maturation in macrophages, However, acidification does occur in these phagosomes, and some of them can eventually mature to phagolysosomes.