Characterization of Helicobacter pyloriVacA-containing vacuoles (VCVs), VacA intracellular trafficking and interference with calcium signalling in T lymphocytes
Characterization of Helicobacter pyloriVacA-containing vacuoles (VCVs), VacA intracellular trafficking and interference with calcium signalling in T lymphocytes
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DOI：
10.1111/cmi.12474
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发表时间：
2015-12-01
影响因子：
3.4
通讯作者：
Haas, Rainer
中科院分区：
文献类型：
--
作者：
Kern, Beate;Jain, Utkarsh;Haas, Rainer
人类病原体幽门螺杆菌感染了全球一半的人口。它位于胃上皮，有助于胃炎、十二指肠溃疡和胃溃疡以及胃癌等疾病的发展。一个主要的因素是分泌的空泡毒素VacA，它在核内体膜上形成阴离子选择通道，导致腔室膨胀，但所产生的含VacA的空泡（vcv）的组成和目的仍然未知。VacA通过多种方式对宿主免疫反应产生影响，包括抑制t细胞的活化和增殖以及抑制宿主免疫反应。在这项研究中，首次全面分析了来自T细胞的VCV的组成，以研究VCV的功能。通过免疫磁分离成功分离vcv，纯化后的液泡用质谱分析。我们检测到一组122个vcv特异性蛋白，这些蛋白与免疫应答、细胞死亡和细胞信号传导过程有关，所有这些都受到VacA的影响。进一步研究的单个蛋白质之一是基质相互作用分子（STIM1），这是一种位于内质网（ER）的钙传感器，在储存操作的钙进入中起重要作用。活细胞成像显微镜数据显示，在内质网中，VacA与STIM1共定位，并表明VacA可能干扰STIM1向质膜定位的钙释放激活的钙通道蛋白ORAI1的运动，以响应Ca2+存储耗尽。此外，VacA抑制Jurkat E6-1 T细胞系和人CD4(+) T细胞中胞质游离Ca2+的增加。在HeLa细胞中证实了内质网中VacA的存在及其向高尔基体的转运，确定这两个细胞区室是新的VacA靶结构。
The human pathogen Helicobacter pylori colonizes half of the global population. Residing at the stomach epithelium, it contributes to the development of diseases such as gastritis, duodenal and gastric ulcers, and gastric cancer. A major factor is the secreted vacuolating toxin VacA, which forms anion-selective channels in the endosome membrane that cause the compartment to swell, but the composition and purpose of the resulting VacA-containing vacuoles (VCVs) are still unknown. VacA exerts influence on the host immune response in various ways, including inhibition of T-cell activation and proliferation and suppression of the host immune response. In this study, for the first time the composition of VCVs from T cells was comprehensively analysed to investigate VCV function. VCVs were successfully isolated via immunomagnetic separation, and the purified vacuoles were analysed by mass spectrometry. We detected a set of 122 VCV-specific proteins implicated among others in immune response, cell death and cellular signalling processes, all of which VacA is known to influence. One of the individual proteins studied further was stromal interaction molecule (STIM1), a calcium sensor residing in the endoplasmic reticulum (ER) that is important in store-operated calcium entry. Live cell imaging microscopy data demonstrated colocalization of VacA with STIM1 in the ER and indicated that VacA may interfere with the movement of STIM1 towards the plasma membrane-localized calcium release activated calcium channel protein ORAI1 in response to Ca2+ store depletion. Furthermore, VacA inhibited the increase of cytosolic-free Ca2+ in the Jurkat E6-1 T-cell line and human CD4(+) T cells. The presence of VacA in the ER and its trafficking to the Golgi apparatus was confirmed in HeLa cells, identifying these two cellular compartments as novel VacA target structures.