A novel receptor - ligand pathway for entry of Francisella tularensis in monocyte-like THP-1 cells: interaction between surface nucleolin and bacterial elongation factor Tu.
A novel receptor - ligand pathway for entry of Francisella tularensis in monocyte-like THP-1 cells: interaction between surface nucleolin and bacterial elongation factor Tu.
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一种新型的受体 - francisella tularensis在单核细胞样THP-1细胞中的配体途径：表面核素与细菌伸长因子TU之间的相互作用。
DOI：
10.1186/1471-2180-8-145
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发表时间：
2008-09-12
期刊：
影响因子：
4.2
通讯作者：
Charbit, Alain
中科院分区：
文献类型：
--
作者：
Barel, Monique;Hovanessian, Ara G.;Meibom, Karin;Briand, Jean-Paul;Dupuis, Marion;Charbit, Alain
土拉热弗朗西丝菌是引起兔热病的病原菌，是人类最具感染性的病原菌之一。它被免疫细胞如单核细胞和巨噬细胞吞噬。启动细菌摄取的确切机制尚未阐明。已经报道了C3、CR 3、A类清道夫受体和甘露糖受体参与细菌摄取。然而，一个额外的，尚未确定的受体的F。已经提出土拉热内化。我们在这里表明，细胞表面表达的核仁素是土拉热弗朗西丝菌活疫苗株（LVS）的受体，并促进LVS结合和感染人单核细胞样THP-1细胞。HB-19假肽特异性结合核仁素的羧基端RGG结构域，抑制LVS结合和单核细胞样THP-1细胞的感染。在下拉分析中，延伸因子Tu（EF-Tu），一个GTP结合蛋白参与蛋白质翻译，通常发现在细胞质中，回收LVS细菌膜蛋白结合在核仁素的RGG结构域。针对重组LVS EF-Tu产生特异性多克隆鼠抗体。通过荧光和电子显微镜实验，我们发现EF-Tu的一部分可以检测到在细菌表面。抗EF-Tu抗体减少LVS与单核细胞样THP-1细胞的结合，并损害感染，即使在缺乏补体和补体受体的情况下。EF-Tu和核仁素之间的相互作用，说明了两个不同的下拉分析使用重组EF-Tu蛋白和RGG结构域的核仁素或细胞溶解的核仁素。总之，我们的研究结果表明，表面核仁素和它的细菌配体EF-Tu之间的相互作用在土拉弗朗西斯菌的粘附和进入过程中起着重要作用，因此可能有助于入侵宿主组织。由于LVS在感染的单核细胞中的吞噬体逃逸和胞内增殖与人类致病性F。tularensis ssp tularensis，进入单核细胞样THP-1细胞的机制，涉及EF-Tu和核仁素之间的相互作用，可能是相似的两个亚种。因此，使用核仁特异性假肽HB-19或重组EF-Tu可以提供用于调节F.土拉菌感染
Francisella tularensis, the causative agent of tularemia, is one of the most infectious human bacterial pathogens. It is phagocytosed by immune cells, such as monocytes and macrophages. The precise mechanisms that initiate bacterial uptake have not yet been elucidated. Participation of C3, CR3, class A scavenger receptors and mannose receptor in bacterial uptake have been already reported. However, contribution of an additional, as-yet-unidentified receptor for F. tularensis internalization has been suggested. We show here that cell-surface expressed nucleolin is a receptor for Francisella tularensis Live Vaccine Strain (LVS) and promotes LVS binding and infection of human monocyte-like THP-1 cells. The HB-19 pseudopeptide that binds specifically carboxy-terminal RGG domain of nucleolin inhibits LVS binding and infection of monocyte-like THP-1 cells. In a pull-down assay, elongation factor Tu (EF-Tu), a GTP-binding protein involved in protein translation, usually found in cytoplasm, was recovered among LVS bacterial membrane proteins bound on RGG domain of nucleolin. A specific polyclonal murine antibody was raised against recombinant LVS EF-Tu. By fluorescence and electron microscopy experiments, we found that a fraction of EF-Tu could be detected at the bacterial surface. Anti-EF-Tu antibodies reduced LVS binding to monocyte-like THP-1 cells and impaired infection, even in absence of complement and complement receptors. Interaction between EF-Tu and nucleolin was illustrated by two different pull-down assays using recombinant EF-Tu proteins and either RGG domain of nucleolin or cell solubilized nucleolin. Altogether, our results demonstrate that the interaction between surface nucleolin and its bacterial ligand EF-Tu plays an important role in Francisella tularensis adhesion and entry process and may therefore facilitate invasion of host tissues. Since phagosomal escape and intra-cytosolic multiplication of LVS in infected monocytes are very similar to those of human pathogenic F. tularensis ssp tularensis, the mechanism of entry into monocyte-like THP-1 cells, involving interaction between EF-Tu and nucleolin, might be similar in the two subspecies. Thus, the use of either nucleolin-specific pseudopeptide HB-19 or recombinant EF-Tu could provide attractive therapeutic approaches for modulating F. tularensis infection.
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影响因子：
2.1
作者：
Balbo, M;Barel, M;Frade, R
通讯作者：
Frade, R
影响因子：
2.8
作者：
DesJardin, LE;Kaufman, TM;Schlesinger, LS
通讯作者：
Schlesinger, LS
DOI：
10.1073/pnas.0504271103
发表时间：
2006-01-03
影响因子：
11.1
作者：
Gavrilin, MA;Bouakl, IJ;Wewers, MD
通讯作者：
Wewers, MD
影响因子：
3.1
作者：
Golovliov, I;Baranov, V;Sjöstedt, A
通讯作者：
Sjöstedt, A
影响因子：
4.4
作者：
Barel, M;Le Romancer, M;Frade, R
通讯作者：
Frade, R