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

描述（由申请人提供）：人体胃肠道内有大量复杂的微生物群落，这些微生物对正常健康很重要，但也可能导致胃肠道癌等疾病。在这项提案中，我们将使用斑马鱼模型来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，以推动肠癌的进展。我们将利用由于Wnt信号通路过度激活、慢性炎症或DNA修复机制缺失而易患肠癌的斑马鱼品系，所有这些都与人类胃肠道癌症有关。在我们的第一个目标中，我们将表征由人类和斑马鱼相关细菌产生的许多分泌蛋白，这些分泌蛋白调节与胃肠道癌症发展相关的宿主程序，包括上皮细胞增殖和炎症。我们将确定促增殖蛋白是否与癌症易感遗传背景协同作用，破坏肠上皮更新的正常程序并引起增生，以及抗炎蛋白是否提供针对增生的保护。在我们的第二个目标中，我们将描述一个转基因斑马鱼线，表达细菌癌基因，CagA，从胃癌相关的病原体幽门螺杆菌。我们将确定在这些转基因鱼向增生和癌症发展过程中激活的宿主遗传程序，并测试CagA的致癌特性需要哪些途径。我们还将测试CagA表达是否以促进肠道病理学的方式改变肠道微生物群落。在我们的第三个目标中，我们将调查一种细菌感染背后的微生物病因学。 在我们的斑马鱼设施中爆发了自发性肠癌，我们已经证明了这种癌症是可以传播的。我们将使用传染性疾病的实验框架来识别与肠道病理学相关的微生物。我们将使用我们的癌症易感斑马鱼系来表征疾病相关微生物群落和单个候选微生物的致癌潜力。这项研究将为肠道微生物促进癌症发展的机制提供新的见解，并最终导致诊断，治疗和预防人类胃肠道癌症的新方法。

DESCRIPTION (provided by applicant): 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.