Nasal colonisation by Staphylococcus aureus depends upon clumping factor B binding to the squamous epithelial cell envelope protein loricrin.
Nasal colonisation by Staphylococcus aureus depends upon clumping factor B binding to the squamous epithelial cell envelope protein loricrin.
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DOI：
10.1371/journal.ppat.1003092
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发表时间：
2012-12
期刊：
影响因子：
6.7
通讯作者：
McLoughlin RM
中科院分区：
文献类型：
--
作者：
Mulcahy ME;Geoghegan JA;Monk IR;O'Keeffe KM;Walsh EJ;Foster TJ;McLoughlin RM
金黄色葡萄球菌无症状地定植于前鼻孔，但促进定植的宿主和细菌因素仍不完全清楚。金黄色葡萄球菌表面蛋白 ClfB 已被证明可以在体外介导鳞状上皮细胞的粘附，并促进小鼠和人类的鼻定植。在这里，我们证明鳞状上皮细胞包膜蛋白 loricrin 代表金黄色葡萄球菌鼻定植期间 ClfB 的主要靶配体。体外粘附测定表明，表达 ClfB 的细菌最有可能通过“对接、锁定和闩锁”机制结合兜甲素。使用表面等离子共振，我们发现 ClfB 与细胞角蛋白 10 (K10)（一种鳞状上皮细胞的结构蛋白）和兜甲蛋白结合，具有相似的亲和力，但在低 µM 范围内。 Loricrin 由三个独立的区域组成，其中包含富含 GS 的 omega 环。每个环分别表达并发现与 ClfB 结合，但区域 2 以最高亲和力结合。为了研究 ClfB 和 loricrin 之间的特异性相互作用是否足以促进金黄色葡萄球菌鼻定植，我们比较了 ClfB+ 金黄色葡萄球菌定植野生型和 loricrin 缺陷 (Lor−/−) 小鼠鼻孔的能力。在没有兜甲素的情况下，金黄色葡萄球菌鼻定植显着受损。此外，ClfB-突变体定植野生型小鼠的效率低于亲本ClfB+品系，而亲本品系和ClfB-突变体在Lor-/-小鼠中观察到类似的较低水平的定植。通过表达 ClfB 的乳酸乳球菌保留在 WT 小鼠的鼻孔中，但不保留在 Lor−/− 小鼠的鼻孔中，证实了 ClfB 通过在体内结合兜甲蛋白来支持鼻定植的能力。通过将体外生化分析与动物模型研究相结合，我们确定了鳞状上皮细胞包膜蛋白 loricrin 作为金黄色葡萄球菌鼻定植期间 ClfB 的靶配体。 金黄色葡萄球菌是一种重要的人类共生菌，永久存在于约 20% 人口的鼻子中，是感染的重要危险因素。促进鼻定植的宿主和细菌因素仍有待充分表征。金黄色葡萄球菌粘附在鼻子中发现的鳞状上皮细胞上。金黄色葡萄球菌表面表达的蛋白质，包括聚集因子 B (ClfB)，是造成这种相互作用的原因。我们证明，鳞状上皮细胞包膜的主要成分 loricrin 代表 ClfB 的主要配体，并且 ClfB 和 loricrin 之间的相互作用是金黄色葡萄球菌有效鼻定植所必需的。使用纯化的蛋白质，我们证明了 ClfB 与 loricrin 结合，并提出了这种结合发生的机制。我们建立了金黄色葡萄球菌鼻定植的小鼠模型，并证明与依赖于 ClfB 的野生型小鼠相比，兜甲蛋白缺陷型小鼠的定植减少。使用乳酸乳球菌作为表达 ClfB 的替代宿主，我们可以证明 ClfB 和鼻孔中的 loricrin 之间的相互作用足以支持鼻定植。总的来说，这些数据表明 ClfB-loricrin 相互作用对于金黄色葡萄球菌鼻定植至关重要。
Staphylococcus aureus asymptomatically colonises the anterior nares, but the host and bacterial factors that facilitate colonisation remain incompletely understood. The S. aureus surface protein ClfB has been shown to mediate adherence to squamous epithelial cells in vitro and to promote nasal colonisation in both mice and humans. Here, we demonstrate that the squamous epithelial cell envelope protein loricrin represents the major target ligand for ClfB during S. aureus nasal colonisation. In vitro adherence assays indicated that bacteria expressing ClfB bound loricrin most likely by the “dock, lock and latch” mechanism. Using surface plasmon resonance we showed that ClfB bound cytokeratin 10 (K10), a structural protein of squamous epithelial cells, and loricrin with similar affinities that were in the low µM range. Loricrin is composed of three separate regions comprising GS-rich omega loops. Each loop was expressed separately and found to bind ClfB, However region 2 bound with highest affinity. To investigate if the specific interaction between ClfB and loricrin was sufficient to facilitate S. aureus nasal colonisation, we compared the ability of ClfB+ S. aureus to colonise the nares of wild-type and loricrin-deficient (Lor−/−) mice. In the absence of loricrin, S. aureus nasal colonisation was significantly impaired. Furthermore a ClfB− mutant colonised wild-type mice less efficiently than the parental ClfB+ strain whereas a similar lower level of colonisation was observed with both the parental strain and the ClfB− mutant in the Lor−/− mice. The ability of ClfB to support nasal colonisation by binding loricrin in vivo was confirmed by the ability of Lactococcus lactis expressing ClfB to be retained in the nares of WT mice but not in the Lor−/− mice. By combining in vitro biochemical analysis with animal model studies we have identified the squamous epithelial cell envelope protein loricrin as the target ligand for ClfB during nasal colonisation by S. aureus. Staphylococcus aureus is an important human commensal, present permanently in the noses of about 20% of the population and representing a significant risk factor for infection. The host and bacterial factors that facilitate nasal colonisation remain to be fully characterised. S. aureus adheres to the squamous epithelial cells found in the nose. Proteins expressed on the surface of S. aureus, including clumping factor B (ClfB), are responsible for this interaction. We demonstrate that loricrin, a major component of the squamous epithelial cell envelope, represents the primary ligand for ClfB and that the interaction between ClfB and loricrin is required for efficient nasal colonisation by S. aureus. Using purified proteins we have demonstrated that ClfB binds loricrin and propose a mechanism by which this binding occurs. We have established a murine model of S. aureus nasal colonisation and have demonstrated reduced colonisation in loricrin-deficient mice compared to wild-type mice which is dependent upon ClfB. Using Lactococcus lactis as a surrogate host expressing ClfB, we could show that the interaction between ClfB and loricrin in the nares is sufficient to support nasal colonisation. Cumulatively, these data show that the ClfB-loricrin interaction is crucial for nasal colonisation by S. aureus.
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影响因子：
6.4
作者：
Monk IR;Shah IM;Xu M;Tan MW;Foster TJ
通讯作者：
Foster TJ
影响因子：
4.2
作者：
Corrigan, Rebecca M.;Miajlovic, Helen;Foster, Timothy J.
通讯作者：
Foster, Timothy J.
影响因子：
3.1
作者：
González-Zorn, B;Senna, JPM;Grillot-Courvalin, C
通讯作者：
Grillot-Courvalin, C
影响因子：
2.9
作者：
Karlsson, R;Katsamba, PS;Myszka, DG
通讯作者：
Myszka, DG
影响因子：
4.8
作者：
CANDI, E;MELINO, G;STEINERT, PM
通讯作者：
STEINERT, PM