How does the parasite causing amoebiasis (Entamoeba histolytica) manage to invade through the intestine?

引起阿米巴病（溶组织内阿米巴）的寄生虫如何侵入肠道？

• 批准号: 444520224
• 负责人: Professorin Dr. Iris Bruchhaus
• 金额: --
• 依托单位: Bernhard-Nocht-Institut für Tropenmedizin (BNITM)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/444520224?language=en
• 关键词: How; does; parasite; causing; amoebiasis

The intestinal parasite Entamoeba histolytica is one of the most important human parasites. Life-threatening amoebic liver abscess (ALA) formation continues to be a common complication of intestinal E. histolytica infections with about 11.300 deaths per year mainly in tropical and subtropical regions with poor hygienic conditions. Usually, E. histolytica colonizes the human intestine without causing severe symptoms. However, these protozoa can penetrate the intestinal wall and lead to ulcerative, bloody intestinal inflammation or induce ALA. The lack of a suitable model system led to the unsatisfactory situation that despite substantial research efforts, the mechanisms of tissue invasion and destruction by E. histolytica and the mechanisms that allow the bypass of the host's immune response are still not well understood. With the proposed project we would like to fill this gap of knowledge and elucidate the mechanisms underlying the invasion process of the protozoan parasite E. histolytica into the host’s intestine. In addition, the response of different host cells to contact with E. histolytica should be studied. This goal will be achieved with the help of E. histolytica clones that are exclusively available to our lab. These clones differ in their ability to form ALAs, but are derived from the same isolate and thus have the same genetic background. In addition, we also have developed a method to manipulate amoebae genetically. With the help of comparative analyses of the clones and their genetic manipulation, we recently have succeeded in identifying a new pathogenicity factor, which will also be subject of the present study. Hypotheses- Pathogenic amoebae and non-pathogenic amoebae can invade tissue similarly effective. However, pathogenic amoebae are more resistant to the immune system, while they induce a more pronounced immunopathology.- Pathogenic amoebae can switch its gene expression faster and thus adapt more quickly to changing conditions during an infection compared to non-pathogenic ones.- The host reacts differently to infection with pathogenic and non-pathogenic amoebae, respectively.- Pathogenic and non-pathogenic amoebae differently regulate the composition of the intestinal microbiome Aim: Understanding the complex interplay between E. histolytica and its host during the process of tissue invasion.Three different experimental models (in vitro intestinal model, self-renewing organoid-derived intestinal cell monolayer model, CBA/J mice intracecal inoculation model) with different levels of complexity will be used to test our hypotheses. In all systems, the interaction of host cells with amoebae with different pathogenicity will be analysed over time using High-Resolution Microscopy and Next Generation Sequencing.

肠道寄生虫溶组织内阿米巴是人类最重要的寄生虫之一。危及生命的阿米巴肝脓肿(ALA)的形成仍然是肠道溶组织埃希菌感染的常见并发症，每年约有11.300人死亡，主要发生在卫生条件较差的热带和亚热带地区。通常情况下，溶组织埃希氏菌在人体肠道内定植，不会引起严重症状。然而，这些原虫可以穿透肠壁，导致溃疡性、血性肠炎或诱发ALA。由于缺乏合适的模型系统，导致尽管进行了大量的研究工作，但对溶组织埃希氏菌入侵和破坏组织的机制以及允许宿主绕过免疫反应的机制仍然不太清楚。通过这个拟议的项目，我们想要填补这一知识空白，并阐明原生动物寄生虫组织溶解杆菌入侵宿主肠道的潜在机制。此外，还应研究不同宿主细胞对接触溶组织埃希氏菌的反应。这一目标将在我们实验室独家提供的溶组性肠杆菌克隆的帮助下实现。这些克隆在形成ALAS的能力上有所不同，但它们来自相同的菌株，因此具有相同的遗传背景。此外，我们还开发了一种从基因上操纵阿米巴的方法。通过对这些克隆及其基因操作的比较分析，我们最近成功地确定了一个新的致病因子，这也将是本研究的主题。假设-致病性阿米巴和非致病性阿米巴可以同样有效地侵入组织。然而，致病性阿米巴对免疫系统的抵抗力更强，同时它们引起更明显的免疫病理。-致病性阿米巴比非致病性阿米巴能更快地切换其基因表达，从而更快地适应感染期间的变化。-致病性和非致病性阿米巴分别对宿主对感染的不同反应。-致病性和非致病性阿米巴不同地调节肠道微生物组的组成目的：了解组织溶解肠杆菌与其宿主在组织入侵过程中的复杂相互作用。三种不同的实验模型(体外肠道模型、自更新类器官来源的肠道细胞单层模型、具有不同复杂程度的CBA/J小鼠鞘内接种模型)将被用来检验我们的假设。在所有系统中，随着时间的推移，将使用高分辨率显微镜和下一代测序来分析宿主细胞与不同致病性的阿米巴的相互作用。