Trafficking and release of mycobacterial lipids from infected macrophages
Trafficking and release of mycobacterial lipids from infected macrophages
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DOI：
10.1034/j.1600-0854.2000.010306.x
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发表时间：
2000-03-01
期刊：
影响因子：
4.5
通讯作者：
Russell, DG
中科院分区：
文献类型：
--
作者：
Beatty, WL;Rhoades, ER;Russell, DG
对感染巨噬细胞的分析显示，分枝杆菌细胞壁的含脂部分被积极地运输出分枝杆菌液泡。为了便于分析含分枝杆菌吞噬体的囊泡运输，用肼标记物标记表面暴露的碳水化合物。通过活细胞的免疫电镜和荧光显微镜分析了标记的碳水化合物/脂质部分的分布以及随后与细胞区室的相互作用。释放的分枝杆菌成分与几种细胞内细胞器相关，并在管状内吞室中显著富集。通过密度梯度电泳对感染的巨噬细胞进行亚细胞分离，发现标记的细菌成分通过早期和晚期内体的时间运动。这些亚细胞组分的薄层色谱分析证实了它们的脂质性质，并揭示了五种优势的细菌来源物种。这些分枝杆菌脂质也存在于从培养基中分离出来的细胞外囊泡中，并可在未感染的“旁观者”细胞中观察到。它们转移到旁边的细胞可以扩大细菌的影响范围，超出宿主细胞的直接限制。
Analysis of infected macrophages revealed that lipid-containing moieties of the mycobacterial cell wall are actively trafficked out of the mycobacterial vacuole. To facilitate the analysis of vesicular trafficking from mycobacteria-containing phagosomes, surface-exposed carbohydrates were labeled with hydrazide-tagged markers. The distribution of labeled carbohydrate/lipid moieties and subsequent interaction with cellular compartments were analyzed by immunoelectron microscopy and by fluorescence microscopy of live cells. The released mycobacterial constituents were associated with several intracellular organelles and were enriched strikingly in tubular endocytic compartments. Subcellular fractionation of infected macrophages by density gradient electrophoresis showed temporal movement of labeled bacterial constituents through early and late endosomes. Thin layer chromatography analysis of these subcellular fractions confirmed their lipid nature and revealed five dominant bacteria-derived species. These mycobacterial lipids were also found in extracellular vesicles isolated from the medium and could be observed in un-infected 'bystander' cells. Their transfer to bystander cells could expand the bacteria's sphere of influence beyond the immediate confines of the host cell.