Neisseria meningitidis Opc invasin binds to the sulphated tyrosines of activated vitronectin to attach to and invade human brain endothelial cells.
Neisseria meningitidis Opc invasin binds to the sulphated tyrosines of activated vitronectin to attach to and invade human brain endothelial cells.
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DOI：
10.1371/journal.ppat.1000911
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发表时间：
2010-05-20
期刊：
影响因子：
6.7
通讯作者：
Virji M
中科院分区：
文献类型：
--
作者：
Sa E Cunha C;Griffiths NJ;Virji M
宿主脉管系统被认为是脑膜炎奈瑟菌（Nm）在全身传播的主要途径，导致易感人群败血症和脑膜炎。在体外，纳米外膜蛋白Opc可以通过血清因子锚定内皮整合素，增强细胞的进出；但其与血清因子结合的机制尚不清楚。本研究表明，在胶囊和胶囊细菌中表达的Nm Opc可以通过首先与血清玻璃体连接蛋白结合，以及在较小程度上与纤维连接蛋白结合，增加人脑内皮细胞系（HBMEC）的粘附和进入。该研究还表明，Opc优先与活化形式的人玻璃体连接蛋白结合，而不是与天然玻璃体连接蛋白结合，除非对后者进行处理以放松其封闭构象。玻璃体连接蛋白的直接结合发生在其连接区（CR），需要硫酸酪氨酸Y56和Y59。因此，Opc/玻璃体连接蛋白的相互作用可以通过针对亚硫酪氨酸的构象依赖单克隆抗体8E6和跨越玻璃体连接蛋白残基43-68的合成硫酸（但未磷酸化或未修饰）肽来抑制。最重要的是，携带细胞结合结构域45RGD47的26聚硫酸肽足以有效地实现脑膜炎球菌对hbmec的侵袭。据我们所知，这是第一个描述细菌粘附素与宿主受体硫酸酪氨酸结合的研究。我们的数据还表明，Opc的单个区域可能与玻璃体连接素和肝素的硫酸化区域相互作用。因此，在没有肝素的情况下，表达Opc的纳米颗粒直接在CR上相互作用，但当被肝素预包被时，它们通过肝素结合到活化的玻璃体连接蛋白的肝素结合区域，尽管其亲和力低于在CR上。这种冗余表明Opc/玻璃体连接蛋白相互作用在脑膜炎球菌发病机制中的重要性，并可能使细菌利用宿主效应分子参与的生理过程的好处。脑膜炎奈瑟菌是一种人类病原体，它可以穿过自然细胞屏障到达血液和大脑，引起败血症和脑膜炎。它的一种表面分子Opc能够附着在血管内壁的人体细胞上。在体外，细菌可以通过用人血清因子玻璃体粘连蛋白包裹自己来做到这一点；而且，通过模仿玻璃体连接蛋白，它可以与人类细胞玻璃体连接蛋白结合蛋白（受体）结合。在这项研究中，我们研究了脑膜炎奈瑟菌识别的玻璃体连接蛋白的结构特征；这些知识可能有助于制定未来控制细菌传播的策略。我们描述了细菌与玻璃体连接蛋白结合的两个不同方面，并证明其中一个是一种新方法，它直接通过玻璃体连接蛋白的硫酸盐酪氨酸发生，只有当分子以未展开的形式呈现时才可用。当细菌存在于血液中时，这种未折叠或激活的玻璃体粘连蛋白水平可能升高。因此，我们的观察表明，当细菌出现在血液中时，它们的存在可能有助于生成玻璃体粘连蛋白，它们需要这种粘连蛋白结合并侵入排列在人体血管上的细胞，从而扩散到包括大脑在内的整个身体组织。
The host vasculature is believed to constitute the principal route of dissemination of Neisseria meningitidis (Nm) throughout the body, resulting in septicaemia and meningitis in susceptible humans. In vitro, the Nm outer membrane protein Opc can enhance cellular entry and exit, utilising serum factors to anchor to endothelial integrins; but the mechanisms of binding to serum factors are poorly characterised. This study demonstrates that Nm Opc expressed in acapsulate as well as capsulate bacteria can increase human brain endothelial cell line (HBMEC) adhesion and entry by first binding to serum vitronectin and, to a lesser extent, fibronectin. This study also demonstrates that Opc binds preferentially to the activated form of human vitronectin, but not to native vitronectin unless the latter is treated to relax its closed conformation. The direct binding of vitronectin occurs at its Connecting Region (CR) requiring sulphated tyrosines Y56 and Y59. Accordingly, Opc/vitronectin interaction could be inhibited with a conformation-dependent monoclonal antibody 8E6 that targets the sulphotyrosines, and with synthetic sulphated (but not phosphorylated or unmodified) peptides spanning the vitronectin residues 43–68. Most importantly, the 26-mer sulphated peptide bearing the cell-binding domain 45RGD47 was sufficient for efficient meningococcal invasion of HBMECs. To our knowledge, this is the first study describing the binding of a bacterial adhesin to sulphated tyrosines of the host receptor. Our data also show that a single region of Opc is likely to interact with the sulphated regions of both vitronectin and of heparin. As such, in the absence of heparin, Opc-expressing Nm interact directly at the CR but when precoated with heparin, they bind via heparin to the heparin-binding domain of the activated vitronectin, although with a lower affinity than at the CR. Such redundancy suggests the importance of Opc/vitronectin interaction in meningococcal pathogenesis and may enable the bacterium to harness the benefits of the physiological processes in which the host effector molecule participates. Neisseria meningitidis is a human pathogen that can cross the natural cellular barriers to reach the blood and the brain, causing septicaemia and meningitis. One of its surface molecules, Opc, has the capacity to attach to human cells lining the blood vessels. In vitro, the bacterium can do this by coating itself with the human serum factor vitronectin; and, by mimicking as vitronectin, it can bind to human cellular vitronectin-binding proteins (receptors). In this study, we have investigated the structural features of vitronectin that N. meningitidis recognises; such knowledge could help develop future strategies to control bacterial spread. We describe two different aspects of bacterial binding to vitronectin and demonstrate that one of these is a novel method, which occurs directly through the sulphated tyrosines of vitronectin available only when the molecule presents itself in an unfolded form. Such unfolded or activated vitronectin levels may be elevated during bacterial presence in the blood. Thus our observations imply that when bacteria appear in the blood, their presence may help to generate the form of vitronectin that they require for binding to and invading the cells that line human blood vessels to spread throughout body tissues including the brain.
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影响因子：
3.4
作者：
Bradley, CJ;Griffiths, NJ;Virji, M
通讯作者：
Virji, M
影响因子：
--
作者：
BAILIN, G
通讯作者：
BAILIN, G
DOI：
10.1084/jem.168.2.507
发表时间：
1988-08-01
期刊：
The Journal of experimental medicine
影响因子：
--
作者：
Achtman M;Neibert M;Crowe BA;Strittmatter W;Kusecek B;Weyse E;Walsh MJ;Slawig B;Morelli G;Moll A
通讯作者：
Moll A
影响因子：
3.8
作者：
Dabo, S. M.;Confer, A. W.;Anderson, B. E.
通讯作者：
Anderson, B. E.
DOI：
10.1016/s0304-4165(89)80019-4
发表时间：
1989-02-24
期刊：
BIOCHIMICA ET BIOPHYSICA ACTA
影响因子：
--
作者：
IZUMI, M;YAMADA, KM;HAYASHI, M
通讯作者：
HAYASHI, M