A Zebrafish Model to Study the Role of the Microbiota in the Etiology of Intestin

项目摘要 人体胃肠道内有大量复杂的微生物群落， 对正常的健康，但也可能有助于疾病，如胃肠道癌症。在本提案中，我们将 使用斑马鱼模型研究肠道微生物产生的因子如何与宿主遗传因子相互作用， 导致肠癌的发展我们将利用斑马鱼品系， 由于Wnt信号通路过度激活、慢性炎症或DNA修复缺失而导致的癌症 所有这些机制通常与人类胃肠道癌症有关。在我们的第一个目标中， 将表征许多分泌蛋白，由人类和斑马鱼相关细菌产生， 调节与胃肠癌发展相关宿主程序，包括上皮细胞 增殖和炎症。我们将确定促增殖蛋白是否协同作用 具有癌症倾向的遗传背景，破坏肠上皮细胞更新的正常程序， 此外，抗炎蛋白是否赋予针对增生的保护。在 我们的第二个目标是表征表达细菌癌基因CagA的转基因斑马鱼系， 与胃癌相关的病原体幽门螺杆菌。我们将确定宿主基因 这些程序在这些转基因鱼向增生和癌症发展的过程中被激活，我们 将测试CagA的致癌特性所需的这些途径。我们还将测试 CagA表达改变肠道微生物群落的方式，促进肠道病理。在我们 第三个目标，我们将调查我们国家自发性肠癌爆发背后的微生物病因。 我们已经证明这种病毒是可以传播的。我们将使用的实验框架 传染性疾病，以确定与肠道病理学相关的微生物。我们会利用我们的癌症- 易患病的斑马鱼品系，以表征疾病相关微生物群落的致癌潜力 和单个候选微生物的研究。这项研究将提供新的洞察机制， 肠道微生物有助于癌症的发展，并最终导致新的方法来诊断， 治疗和预防人类胃肠道癌症。

PROJECT SUMMARY The human gastrointestinal tract houses large and complex communities of microorganisms that are important for normal health, but can also contribute to diseases such as gastrointestinal cancer. In this proposal we will use a zebrafish model to investigate how factors produced by gut microbes interact with host genetic factors to drive the progression of intestinal cancer. We will make use of zebrafish lines that are predisposed to intestinal cancer due to over-activation of the Wnt signaling pathway, chronic inflammation, or loss of DNA repair mechanisms, all of which are commonly associated with gastrointestinal cancers in humans. In our first aim we will characterize a number of secreted proteins, produced by both human and zebrafish-associated bacteria, that modulate host programs associated with gastrointestinal cancer development, including epithelial cell proliferation and inflammation. We will determine whether the pro-proliferative proteins interacts synergistically with cancer-prone genetic backgrounds to disrupt normal programs of intestinal epithelial renewal and cause hyperplasia, and furthermore whether the anti-inflammatory proteins confer protection against hyperplasia. In our second aim we will characterize a transgenic zebrafish line that expresses the bacterial oncogene, CagA, from the stomach cancer-associated pathogen Helicobacter pylori. We will determine the host genetic programs that are activated during the progression of these transgenic fish to hyperplasia and cancer, and we will test which of these pathways are required for CagA's carcinogenic properties. We will also test whether CagA expression alters the intestinal microbial community in ways that promote intestinal pathology. In our third aim we will investigate the microbial etiology behind an outbreak of spontaneous intestinal cancers in our zebrafish facility, which we have shown to be transmissible. We will use the experimental framework of transmissible disease to identify microbes associated with intestinal pathology. We will employ our cancer- prone zebrafish lines to characterize the carcinogenic potential of disease-associated microbial communities and of individual candidate microbes. This research will provide new insight into the mechanisms by with intestinal microbes contribute to cancer development and will ultimately lead to new approaches to diagnose, treat and prevent gastrointestinal cancers in humans.