Helicobacter pylori cag Pathogenicity Island and Gastric Carcinogenesis

革兰氏阴性菌幽门螺杆菌对人胃的持续定植 与胃腺癌发生的风险增加有关。幽门螺杆菌分离株 不同的人类表现出相当程度的遗传多样性。存在的一个染色体区域 在一些幽门螺杆菌菌株中有cag致病岛(PAI)，这是一个预测的40kb区域，但在其他菌株中没有 来编码27种不同的蛋白质。携带CAG致病岛的幽门螺杆菌菌株与 与缺乏CAG致病岛的菌株相比，胃癌发病率显著更高。 CAG PAI编码一种效应蛋白CagA，它通过IV型转移到上皮细胞中 分泌过程。 这项工作的长期目标是确定幽门螺杆菌CAG PAI阳性菌株的机制 诱发胃癌。我们实验室最近的研究表明，盐在调节 CagA表达和调节幽门螺杆菌引起异常上皮细胞反应的能力。这些 这些发现，加上大量文献表明食盐在胃癌中的作用，使我们 为了提出研究盐调节CagA表达的机制的实验， 体外研究盐对H.py/Ori诱导的细胞信号转导的影响，以及盐对H. Py/On在体内诱导疾病进展。 目的1研究盐对CagA基因表达的调控机制。我们 将使用多种实验方法，包括将基因突变引入幽门螺杆菌，分离 对DNA-蛋白质复合体进行分析，并对这种复合体进行质谱分析。AIM 2将调查 幽门螺杆菌菌株表达突变形式的胃上皮细胞的变化 卡加。选择用于分析的表型将包括CagA转位到宿主细胞，诱导IL-8 分泌，(3-连环蛋白激活和EGFR反式激活(与Peek和Polk博士合作， 和细胞凋亡，因为这些表型中的每一种都与胃病的发病机制有关 癌症。Aim 3将把这些体外结果扩展到H.py/或/诱发癌症的啮齿动物模型中，这些模型已经被 由Peek博士开发，包括INS气体小鼠和蒙古沙鼠。 这些研究应该会导致我们在理解分子机制方面取得重要进展 幽门螺杆菌对胃上皮细胞信号转导的调节作用及促进胃发育的作用 癌症。归根结底，这些研究应该会在预防和治疗恶性肿瘤方面取得进展。 在慢性炎症的背景下发展起来的。

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.