Regulation of Helicobacter pylori pili encoded by the cag pathogenicity island

描述（由申请人提供）： 标题：H.由cag致病岛Jennifer A.编码的幽门螺杆菌皮利。Gaddy博士 幽门螺杆菌是人类胃内主要的原核生物，可引起持续性慢性炎症。H.幽门螺杆菌感染是导致消化性溃疡和胃腺癌的主要危险因素。腺癌的发展取决于多种因素，包括宿主遗传学、饮食和细菌因素。细菌致病的一个特殊特征是H。幽门 cag-PAI是一种cag-pathogenicity island，它编码一个IV型分泌系统（T4 SS），负责将致癌蛋白CagA递送到胃上皮细胞中。T4 SS装置跨越两个细菌膜，并且包括被称为T4 SS菌毛的细胞外细胞器。这种细胞器被认为是负责损害真核细胞膜，从而允许CagA易位。虽然T4 SS在H.幽门螺杆菌的发病机制和最终的致癌作用，调节组装这个复杂的分子机器的机制在很大程度上是模糊的。本申请提出的实验，将阐明机制，其中的CAG T4 SS的组装和活动进行调节。初步结果表明，铁和锌等金属有助于调节T4 SS。我们将使用高分辨率电子显微镜观察T4 SS菌毛在不同条件下的金属的可用性，结合生物化学和分子生物学技术，以评估在这些条件下菌毛组件的表达。我们还将使用细菌遗传学作为工具来研究细菌金属稳态对cag-PAI T4 SS调节的贡献。最后，我们将利用啮齿动物感染模型和操纵饮食金属摄入量，以确定营养金属对疾病进展和脊椎动物宿主内T4 SS调节的影响，将实验室实验转化为体内模型。这项研究计划将推进我们在细菌致病机理领域的知识，特别是在H。pylori毒力因子对胃癌等胃疾病的调控作用。

DESCRIPTION (provided by applicant): Title: Regulation of H. pylori pili encoded by the cag pathogenicity island Jennifer A. Gaddy, Ph.D. Helicobacter pylori is the predominant colonizing prokaryote in the human gastric niche, causing persistent chronic inflammation. H. pylori infection is a strong risk factor for the development of peptic ulceration and gastric adenocarcinoma. The development of adenocarcinoma is dependent upon a variety of factors including host genetics, diet, and bacterial factors. One specific feature that contributes to bacterial pathogenesis is the H. pylori cag-pathogenicity island (cag-PAI), which encodes a type IV secretion system (T4SS) responsible for the delivery of the oncogenic protein CagA into gastric epithelial cells. The T4SS apparatus spans two bacterial membranes and includes an extracellular organelle referred to as the T4SS pilus. This organelle is proposed to be responsible for compromising the eukaryotic membrane and thereby allowing translocation of CagA. Although the T4SS has an important role in H. pylori pathogenesis and ultimately carcinogenesis, the mechanisms that regulate assembly of this complex molecular machine are largely obscure. This application proposes experiments that will elucidate mechanisms by which assembly and activity of the cag T4SS are regulated. Preliminary results indicate that metals such as iron and zinc contribute to the regulation of the T4SS. We will use high resolution electron microscopy to visualize the T4SS pilus under different conditions of metal availability in conjunction with biochemical and molecular biology techniques to evaluate the expression of pilus components in these conditions. We will also use bacterial genetics as a tool to investigate the contribution of bacterial metal homeostasis to the regulation of the cag-PAI T4SS. Finally, we will translate the laboratory experiments into an in vivo model by utilizing rodent models of infection and manipulating the dietary metal intake to determine the effect of nutrient metal upon disease progression and the regulation of the T4SS within a vertebrate host. This research plan will advance our knowledge in the area of bacterial pathogenesis, and specifically in the contribution of H. pylori virulence factor regulation to gastric diseases such as cancer.