Helicobacter pylori cag Pathogenicity Island and Gastric Carcinogenesis

幽门螺杆菌致病岛与胃癌发生

• 批准号: 8413059
• 负责人: TIMOTHY L COVER
• 金额: $ 21.07万
• 依托单位: VANDERBILT UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-01-01 至 2013-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8413059
• 关键词: Apoptosis; Bacterial Infections; Cells; Chronic; Collaborations; Complex; DNA; Development; Diet; Disease Progression; Epidermal Growth Factor Receptor; Epithelial Cells; Exhibits; Gastric Adenocarcinoma; Gastric mucosa; Gene Mutation; Genetic Variation; Gerbils; Goals; Gram-Negative Bacteria; Helicobacter pylori; Human; IL8 gene; In Vitro; Incidence; Inflammation; Laboratories; Lead; Literature; Malignant Neoplasms; Mass Spectrum Analysis; Molecular; Mus; Pathogenesis; Pathogenicity Island; Phenotype; Prevention therapy; Proteins; Research; Risk; Rodent Model; Role; Signal Transduction; Sodium Chloride; Stomach; Transactivation; Work; carcinogenesis; in vivo; malignant stomach neoplasm; mutant; novel strategies; protein complex; research study; response; secretion process

Persistent colonization of the human stomach with the Gram-negative bacterium Helicobacter pylori is associated with an increased risk for the development of gastric adenocarcinoma. H. pylori isolates from different humans exhibit a considerable level of genetic diversity. One chromosomal region that is present in some H. pylori strains but not others is the cag pathogenicity island (PAI), a 40 kb region that is predicted to encode 27 different proteins. H. pylori strains harboring the cag pathogenicity island are associated with a significantly higher rate of gastric cancer incidence than are strains that lack the cag pathogenicity island. The cag PAI encodes an effector protein, CagA, that is translocated into epithelial cells via a type IV secretion process. The long-term goal of this work is to define mechanisms through which H. pylori cag PAI-positive strains induce gastric cancer. Recent studies in our laboratory have revealed an important role of salt in regulating CagA expression and in modulating the ability of H. pylori to cause aberrant epithelial cell responses. These findings, in conjunction with extensive literature indicating a role of dietary salt in gastric cancer, have led us to propose experiments that investigate the mechanism by which salt modulates CagA expression, investigate effects of salt on H. py/ori-induced cell signaling in vitro, and investigate effects of salt on H. py/on-induced disease progression in vivo. Aim 1 proposes to analyze the regulatory mechanisms through which salt regulates expression of CagA. We will use multiple experimental approaches, including introduction of genetic mutations into H. pylori, isolation of DNA-protein complexes, and mass spectrometry analysis of such complexes. Aim 2 will investigate alterations in gastric epithelial cells that occur in response to H. pylori strains that express mutant forms of CagA. Phenotypes selected for analysis will include translocation of CagA into host cells, induction of IL-8 secretion, (3-catenin activation and EGFR transactivation (in collaboration with Drs. Peek and Polk, respectively), and apoptosis, since each of these phenotypes is relevant to the pathogenesis of gastric cancer. Aim 3 will extend these in vitro results into rodent models of H. py/or/-induced cancer that have been developed by Dr. Peek, including INS-GAS mice and Mongolian gerbils. These studies should lead to important advances in our understanding of the molecular mechanisms by which H. pylori modulates signaling in gastric epithelial cells and stimulates the development of gastric cancer. Ultimately, these studies should lead to advances in the prevention and therapy of malignancies that develop in the setting of chronic inflammation.

用革兰氏阴性细菌的幽门螺杆菌持续定植人胃 与胃腺癌发展的风险增加有关。幽门螺杆菌从 不同的人类表现出相当多的遗传多样性。存在的一个染色体区域 在某些幽门螺杆菌菌株中，而不是其他菌株是CAG致病岛（PAI），这是一个40 KB的区域，可预测 编码27种不同的蛋白质。藏有CAG致病性岛的幽门螺杆菌菌株与 与缺乏CAG致病岛的菌株相比，胃癌发生率的率明显高。 CAG PAI编码效应蛋白CAGA，该蛋白通过IV型转移到上皮细胞中 分泌过程。 这项工作的长期目标是定义幽门螺杆菌CAG阳性应变的机制 诱导胃癌。我们实验室的最新研究揭示了盐在调节中的重要作用 CAGA表达并调节幽门螺杆菌引起异常上皮细胞反应的能力。这些 发现，结合广泛的文献表明饮食盐在胃癌中的作用已导致我们 提出了研究盐调节CAGA表达的机制的实验， 研究盐在体外对H. py/Ori诱导的细胞信号传导的影响，并研究盐对H. Py/On诱导的体内疾病进展。 AIM 1建议分析盐调节CAGA表达的调节机制。我们 将使用多种实验方法，包括将遗传突变引入幽门螺杆菌，分离 DNA-蛋白质复合物以及此类复合物的质谱分析。 AIM 2将调查 响应于幽门螺杆菌菌株的胃皮细胞的改变，表达突变形式的 卡加。选择用于分析的表型将包括将CAGA转移到宿主细胞中，诱导IL-8 分泌（3-catenin激活和EGFR反式激活（与Peek和Polk博士合作， 分别）和凋亡，因为这些表型都与胃的发病机理有关 癌症。 AIM 3将将这些体外结果扩展到H. py/OR/或/诱导的癌症的啮齿动物模型中 由Peek博士开发，包括Ins-Gas小鼠和蒙古Gerbils。 这些研究应导致我们对分子机制的理解，从 幽门螺杆菌调节胃上皮细胞中的信号传导并刺激胃的发展 癌症。最终，这些研究应导致预防和治疗恶性肿瘤的进步 在慢性炎症的情况下发展。