The pneumococcal serine-rich repeat protein is an intra-species bacterial adhesin that promotes bacterial aggregation in vivo and in biofilms.
The pneumococcal serine-rich repeat protein is an intra-species bacterial adhesin that promotes bacterial aggregation in vivo and in biofilms.
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DOI：
10.1371/journal.ppat.1001044
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发表时间：
2010-08-12
期刊：
影响因子：
6.7
通讯作者：
Orihuela CJ
中科院分区：
文献类型：
--
作者：
Sanchez CJ;Shivshankar P;Stol K;Trakhtenbroit S;Sullam PM;Sauer K;Hermans PW;Orihuela CJ
肺炎链球菌富丝氨酸重复蛋白(PsrP)是一种编码粘附素的致病岛，与肺炎链球菌引起侵袭性疾病的能力呈正相关。先前的研究表明，PsrP通过位于碱性区域(BR)结构域的273-341位氨基酸，介导细菌与肺细胞表面的角蛋白10(K10)的附着。在这项研究中，我们确定PsrP的BR结构域还介导了种内相互作用，促进了感染小鼠的鼻咽和肺部以及成熟生物膜的连续流过模型中大细菌聚集体的形成。利用多种方法，包括用缺失BR结构域的突变体互补，用Cy3标记的重组(R)BR进行荧光显微镜观察，细菌裂解产物的Far Western blotting，与RBR的免疫共沉淀，以及在抗体和竞争多肽存在下生物膜的生长，我们确定BR结构域，特别是PsrP的122-166氨基酸促进了细菌聚集，并且针对BR结构域的抗体是中和的。使用类似的方法，我们还确定了金黄色葡萄球菌和戈登链球菌的富含丝氨酸重复蛋白(SRRP)SRAP和GspB也促进了细菌聚集，并且它们的非重复结构域与各自的SRRP结合。这是首次报道肺炎链球菌感染动物的肺部存在生物膜样结构，并表明SRRPs具有宿主和细菌粘附素的双重作用。这些研究表明，重组的SRRPs非重复结构域(即肺炎链球菌的BR)可能有助于作为疫苗抗原来保护引起感染的革兰氏阳性细菌。富丝氨酸重复蛋白(SRRPs)是一类表面表达蛋白，广泛存在于多种革兰氏阳性病原体中，包括金黄色葡萄球菌、肺炎链球菌、B组链球菌和引起感染性心内膜炎的口腔链球菌。对于所有这些细菌，SRRPs已被证明在与组织的黏附和侵袭性疾病的发展中发挥关键作用。现已知道，生物膜的形成是细菌致病的重要步骤。生物膜中的细菌在新陈代谢、基因表达和蛋白质生产方面有差异，这有助于增强表面粘附性和感染的持久性。在这里，我们描述了PsrP的一个新角色，肺炎链球菌SRRP，作为一种种内细菌粘附素，在肺炎期间促进感染小鼠肺部的细菌聚集。在体外，我们证明了PsrP的基本区域结构域促进了自我相互作用，导致更密集的生物膜，更大的生物膜生物量，并改变了表面生长的培养物的结构；这些相互作用可以被抗PsrP的抗体中和，这些抗体对肺炎球菌感染具有保护作用。我们还证明了金黄色葡萄球菌和戈登链球菌的SRRP也具有种内细菌粘附素的功能。因此，我们认为SRRPs具有宿主细胞和种内细菌粘附素的双重作用。
The Pneumococcal serine-rich repeat protein (PsrP) is a pathogenicity island encoded adhesin that has been positively correlated with the ability of Streptococcus pneumoniae to cause invasive disease. Previous studies have shown that PsrP mediates bacterial attachment to Keratin 10 (K10) on the surface of lung cells through amino acids 273–341 located in the Basic Region (BR) domain. In this study we determined that the BR domain of PsrP also mediates an intra-species interaction that promotes the formation of large bacterial aggregates in the nasopharynx and lungs of infected mice as well as in continuous flow-through models of mature biofilms. Using numerous methods, including complementation of mutants with BR domain deficient constructs, fluorescent microscopy with Cy3-labeled recombinant (r)BR, Far Western blotting of bacterial lysates, co-immunoprecipitation with rBR, and growth of biofilms in the presence of antibodies and competitive peptides, we determined that the BR domain, in particular amino acids 122–166 of PsrP, promoted bacterial aggregation and that antibodies against the BR domain were neutralizing. Using similar methodologies, we also determined that SraP and GspB, the Serine-rich repeat proteins (SRRPs) of Staphylococcus aureus and Streptococcus gordonii, respectively, also promoted bacterial aggregation and that their Non-repeat domains bound to their respective SRRPs. This is the first report to show the presence of biofilm-like structures in the lungs of animals infected with S. pneumoniae and show that SRRPs have dual roles as host and bacterial adhesins. These studies suggest that recombinant Non-repeat domains of SRRPs (i.e. BR for S. pneumoniae) may be useful as vaccine antigens to protect against Gram-positive bacteria that cause infection. Serine-rich repeat proteins (SRRPs) are a family of surface-expressed proteins found in numerous Gram-positive pathogens, including Staphylococcus aureus, Streptococcus pneumoniae, Group B streptococci, and the oral streptococci that cause infective endocarditis. For all of these bacteria, SRRPs have been demonstrated to play pivotal roles in adhesion to tissues and the development of invasive disease. It is now known that biofilm formation is an important step for bacterial pathogenesis. Bacteria in biofilms have been shown to have differences in metabolism, gene expression, and protein production that contribute to enhanced surface adhesion and the persistence of an infection. Herein we describe a novel role for PsrP, the S. pneumoniae SRRP, as an intra-species bacterial adhesin that promotes bacterial aggregation in the lungs of infected mice during pneumonia. In vitro we show that the Basic Region domain of PsrP promotes self-interactions that result in denser biofilms, greater biofilm biomass, and altered architectures of surface grown cultures; these interactions could be neutralized by antibodies to PsrP that are protective against pneumococcal infection. We also demonstrate that the SRRPs of S. aureus and Streptococcus gordonii also function as intra-species bacterial adhesins. Therefore we conclude that SRRPs have dual roles as host-cell and intra-species bacterial adhesins.
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