Analysis of newly identified adhesin used by pathogenic Gram-negative bacteria

描述（由申请人提供）：本提案的目的是表征在大多数革兰氏阴性致病性动物细菌中发现的一种新的多价粘附分子（MAM7）。我们认为MAM7参与了细菌病原体与宿主细胞的初始接触。作为这类分子的代表，我们将使用来自副溶血性弧菌的MAM7蛋白来研究其与宿主细胞的多价结合。副溶血性弧菌是一种通过食用生的或未煮熟的海鲜引起胃肠炎的新兴病原体。我们观察到宿主细胞中肌动蛋白骨架的MAM7依赖性变化。我们预测，MAM7的结合将触发细菌病原体中更多粘附因子的产生。因此，作为我们的目标之一，我们想要揭示细菌和宿主细胞中在MAM7结合时激活的信号机制。在另一个目标中，我们想要了解MAM7与其两种宿主细胞受体，纤维连接蛋白和磷脂酸的生化相互作用。这一信息对于未来针对MAM7抑制剂的研究是非常有价值的。最后，我们观察到表达MAM7的非致病菌（BL21-MAM7）与宿主细胞结合可改善表达MAM7的革兰氏阴性病原体的细胞毒性。我们感兴趣的是确定MAM7在多大程度上比其他类型的细菌病原体提供竞争优势，这些细菌病原体不表达MAM7，但表达其他类型的粘附素。总之，这些实验将使我们能够表征新发现的多价粘附分子MAM7，并将有助于阐明其作为多种细菌病原体竞争性抑制剂的价值。

DESCRIPTION (provided by applicant): The aim of this proposal is to characterize a newly multivalent adhesion molecule (MAM7) found in the majority of Gram-negative pathogenic animal bacteria. We propose that MAM7 is involved in the initial contact of bacterial pathogens with host cells. As a representative for this type of molecule, we will use the MAM7 protein from Vibrio parahaemolyticus, an emerging pathogen that causes gastroenteritis through consumption of raw or undercooked seafood, to study the multivalent binding to host cells. We observe MAM7 dependent changes in the actin cytoskeleton in host cells. We predict that binding of MAM7 will trigger the production of more adhesion factors in the bacterial pathogens. Thus as one of our aims, we would like to uncover the signaling machinery activated in the bacteria and the host cell upon binding of MAM7. In another aim, we would like to understand the biochemical interaction of MAM7 with its two host cell receptors, fibronectin and phosphatidic acid. This information will be extremely valuable for future studies focused on MAM7 inhibitors. Finally, we observe that binding of non-pathogenic bacteria expressing MAM7 (BL21-MAM7) to host cells ameliorates cytotoxicity of Gram-negative pathogens expressing MAM7. We are interested in determining how broadly MAM7 provides a competitive advantage over other types of bacterial pathogens that do not express MAM7 but other types of adhesins. Together, these experiments will allow us to characterize the newly identified multivalent adhesion molecule MAM7 and will help to elucidate its value as a competitive inhibitor for a wide variety of bacterial pathogens. PUBLIC HEALTH RELEVANCE: The aim of this proposal is to characterize a newly identified multivalent adhesion molecule (MAM7) that mediates the initial interaction between the eukaryotic host and the bacterial pathogen. We will use the MAM7 from Vibrio parahaemolyticus, an emerging pathogen that causes gastroenteritis through consumption of raw or undercooked sea food, to study the host/pathogen crosstalk upon binding of MAM7 to the previously identified host cell receptors, determine the biochemical interaction of host receptors with MAM7 and elucidate the value of MAM7 in augmenting bacterial infections.