Pathogenesis of Helicobacter pylori infection

幽门螺杆菌是一种革兰氏阴性细菌，定植在人类胃中。H.幽门螺杆菌感染是 与远端胃癌以及消化性溃疡的风险增加有关。世界 卫生组织已将H.幽门螺杆菌为I型致癌物，而胃癌是第三大致癌物 全球癌症相关死亡的原因。这项工作的长期目标是了解分子 机制，使H。幽门螺杆菌持续定植于人胃粘膜，了解 H.幽门螺杆菌感染会导致胃癌或消化性溃疡的发展 溃疡，并制定有效的战略，预防这些疾病。为了实现这些长期目标， 目标，我们试图了解细菌蛋白质的行动，是本地化的表面H。幽门。H. 幽门螺杆菌基因组包含超过50个基因，预计编码外膜蛋白（OMP）。 据报道，几种OMP介导H。幽门螺杆菌粘附胃上皮细胞，但功能 大多数H。pylori OMP未知。这个建议的总体假设是H。幽门利用 在感染过程的各个阶段的特异性OMP，以优化胃的初始定殖， 在胃粘膜炎症反应存在的情况下促进持续定植，从而 促进胃病的发展。具体目标是：（一）确定两个机构的作用： 组成部分信号转导系统（TCS）在调节基因编码外膜蛋白，（ii）定义外膜蛋白， 在促进H.幽门螺杆菌定植的胃，和（iii）定义的时间特征， 特定OMPs促进H.幽门螺杆菌在胃中定植并调节发育 胃病的症状为了实现目标1，我们将比较野生型和突变株的转录组， 使用RNA-seq和定量RT-PCR方法。为了实现目标2，我们将用以下文库感染小鼠： 在编码OMP的蛋白质中含有突变的菌株，每个菌株用不同的核苷酸条形码标记，和 然后将使用高通量测序来分析在胃中定殖的细菌群体。到 为了实现目标3，我们将通过使用一种新的免疫调节剂来调节所选的OMP编码基因的体内表达。 诱导型启动子总的来说，这些实验将提供重要的新的见解，具体的作用， OMPs在促进胃的初始定植，持久性和疾病。

Helicobacter pylori is a Gram-negative bacterium that colonizes the human stomach. H. pylori infection is associated with an increased risk of cancer of the distal stomach, as well as peptic ulcer disease. The World Health Organization has classified H. pylori as a type I carcinogen, and gastric cancer is the third leading cause of cancer-related death worldwide. The long-term goals of this work are to understand the molecular mechanisms that allow H. pylori to persistently colonize the human gastric mucosa, to understand the molecular mechanisms by which H. pylori infection leads to the development of gastric cancer or peptic ulceration, and to develop effective strategies for the prevention of these diseases. To achieve these long-term goals, we seek to understand the actions of bacterial proteins that are localized on the surface of H. pylori. H. pylori genomes contain more than 50 genes that are predicted to encode outer membrane proteins (OMPs). Several OMPs have been reported to mediate H. pylori adherence to gastric epithelial cells, but the functions of most H. pylori OMPs are not known. The overall hypothesis of this proposal is that H. pylori utilizes specific OMPs at various stages of the infectious process to optimize initial colonization of the stomach and to facilitate persistent colonization in the presence of a gastric mucosal inflammatory response, thereby contributing to the development of gastric disease. The specific aims are (i) To define the role of two- component signal transduction systems (TCSs) in regulating genes encoding OMPs, (ii) To define OMPs that have a dominant role in promoting H. pylori colonization of the stomach, and (iii) To define temporal features of processes by which specific OMPs promote H. pylori colonization of the stomach and modulate development of gastric disease. To accomplish Aim 1, we will compare the transcriptomes of wild-type and mutant strains, using RNA-seq and quantitative RT-PCR methods. To accomplish Aim 2, we will infect mice with a library of strains containing mutations in OMP-encoding proteins, each labeled with a distinct nucleotide bar code, and then will use high throughput sequencing to analyze the bacterial populations colonizing the stomach. To accomplish Aim 3, we will regulate the expression of selected OMP-encoding genes in vivo through use of an inducible promoter. Collectively, these experiments will provide important new insights into the roles of specific OMPs in promoting initial colonization of the stomach, persistence and disease.