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

溶组织内阿米巴肠道寄生虫是人类最重要的寄生虫之一。危及生命的阿米巴肝脓肿（ALA）形成仍然是肠溶组织芽胞杆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差的热带和亚热带地区。通常，溶组织芽胞杆菌在人体肠道中定植而不会引起严重症状。然而，这些原生动物可以穿透肠壁，导致溃疡性、血性肠道炎症或诱发ALA。由于缺乏合适的模型系统，尽管进行了大量的研究，但溶组织芽胞杆菌入侵和破坏组织的机制以及允许绕过宿主免疫反应的机制仍然没有得到很好的理解。在这个项目中，我们希望填补这一知识空白，并阐明原生动物溶组织疟原虫入侵宿主肠道的机制。此外，还应研究不同宿主细胞与溶组织芽胞杆菌接触的反应。这一目标将在我们实验室独家提供的溶组织芽胞杆菌克隆的帮助下实现。这些克隆在形成阿拉斯的能力上有所不同，但它们来自相同的分离物，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变形虫的方法。通过对克隆及其基因操作的比较分析，我们最近成功地鉴定了一种新的致病因子，这也是本研究的主题。假设-致病性变形虫和非致病性变形虫侵入组织的效果相似。然而，致病性变形虫对免疫系统的抵抗力更强，同时它们会引起更明显的免疫病理。-与非致病性变形虫相比，致病性变形虫可以更快地转换其基因表达，从而更快地适应感染期间不断变化的条件。-宿主对致病性和非致病性阿米巴虫感染的反应不同。致病性和非致病性变形虫对肠道微生物组组成的调节不同目的：了解溶组织芽胞杆菌与宿主在组织入侵过程中的复杂相互作用。我们将使用三种不同复杂程度的实验模型（体外肠道模型、自我更新类器官来源的肠道细胞单层模型、CBA/J小鼠肠内接种模型）来验证我们的假设。在所有系统中，宿主细胞与具有不同致病性的变形虫的相互作用将随着时间的推移使用高分辨率显微镜和下一代测序进行分析。

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.