Diversification of the AlpB Outer Membrane Protein of Helicobacter pylori Affects Biofilm Formation and Cellular Adhesion.
Diversification of the AlpB Outer Membrane Protein of Helicobacter pylori Affects Biofilm Formation and Cellular Adhesion.
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DOI：
10.1128/jb.00729-16
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发表时间：
2017-03-15
影响因子：
3.2
通讯作者：
Kamiya S
中科院分区：
文献类型：
--
作者：
Yonezawa H;Osaki T;Fukutomi T;Hanawa T;Kurata S;Zaman C;Hojo F;Kamiya S
幽门螺杆菌是人类最常见的细菌感染原因之一，它在人的胃粘膜上皮和体外非生物表面形成生物膜。细菌生物膜不仅是环境生存的关键，也是成功感染的关键。我们之前从日本十二指肠和胃溃疡患者中分离到的菌株TK1402在体外比其他菌株具有更高的生物被膜形成能力。此外，我们还发现外膜小泡(OMV)在生物膜的形成中起着重要作用。本研究的目的是分析OMV中的哪种蛋白(S)与TK1402生物膜的形成有关。我们从缺乏生物膜形成能力的TK1402出发，获得了一株自发突变菌株。比较了该突变株与野生型OMV的蛋白质组分，发现突变株OMV的外膜蛋白AlpB较野生型显著降低。TK1402alpB对突变菌株的修复完全恢复了生物被膜的形成能力。然而，其他菌株的alpB修复显示生物被膜形成能力的不完全恢复。因此，我们推测AlpB可变区(第121~146位氨基酸)与TK1402生物膜的形成有关。此外，AlpB序列的多样化被证明影响与AGS细胞的黏附能力。这些结果对幽门螺杆菌寄主定植的分子机制有了新的认识。细菌生物膜不仅是环境生存的关键，也是成功感染的关键。幽门螺杆菌细胞表面粘附素介导的幽门螺杆菌黏附宿主细胞的机制一直是许多研究的重点，但对幽门螺杆菌生物被膜形成的相关因素知之甚少。我们的研究表明，AlpB在生物膜的形成中起着重要的作用，并且这种特性依赖于AlpB的特定序列。这反过来又被证明是粘附胃细胞的能力的重要因素。我们预计这些结果将为幽门螺杆菌定植的分子机制提供新的见解。
Helicobacter pylori is one of the most common causes of bacterial infection in humans, and it forms biofilms on human gastric mucosal epithelium as well as on in vitro abiotic surfaces. Bacterial biofilm is critical not only for environmental survival but also for successful infection. We previously demonstrated that strain TK1402, which was isolated from a Japanese patient with duodenal and gastric ulcers, has high biofilm-forming ability in vitro relative to other strains. In addition, we showed that outer membrane vesicles (OMV) play an important role in biofilm formation. The aim of this study was to analyze which protein(s) in the OMV contributes to biofilm formation in TK1402. We obtained a spontaneous mutant strain derived from TK1402 lacking biofilm-forming ability. The protein profiles of the OMV were compared between this mutant strain and the wild type, and it was found that AlpB, an outer membrane protein in the OMV of the mutant strain, was markedly decreased compared to that of the wild type. Restoration of TK1402 alpB to the mutant strain fully recovered the ability to form biofilm. However, restoration with alpB from other strains demonstrated incomplete recovery of biofilm-forming ability. We therefore inferred that the variable region of AlpB (amino acid positions 121 to 146) was involved in TK1402 biofilm formation. In addition, diversification of the AlpB sequence was shown to affect the ability to adhere to AGS cells. These results demonstrate a new insight into the molecular mechanisms of host colonization by H. pylori. IMPORTANCE Bacterial biofilm is critical not only for environmental survival but also for successful infection. The mechanism of Helicobacter pylori adherence to host cells mediated by cell surface adhesins has been the focus of many studies, but little is known regarding factors involved in H. pylori biofilm formation. Our study demonstrated that AlpB plays an important role in biofilm formation and that this property depends upon the specific sequence of alpB. This in turn was shown to be important in the ability to adhere to gastric cells. We anticipate that these results will provide new insight into the molecular mechanisms of H. pylori colonization.