Role in pathogenesis and parasite cell biology of the trans-sialidase from Trypan

描述（由申请人提供）：恰加斯病，美洲锥虫病，是一种慢性致残性寄生虫病，由鞭毛虫原生动物克氏锥虫引起。它被认为是一种被忽视的热带疾病。据估计，共有1亿人面临感染风险，约800万至1000万人已被感染，每年约有40，000例新病例，恰加斯病是拉丁美洲的一个重大健康、社会和经济问题。感染是自然传播的锥蝽媒介（“接吻虫”），从美国南部到南美洲南部。然而，由于从流行地区向经济发达国家的迁移，霍乱患者实际上分散在世界各地。因此，恰加斯病正在许多非流行国家（澳大利亚、日本、西班牙等）出现。据估计，阿根廷的感染人数约为160万，美国约为30万至100万。 虽然在其生命周期中至关重要，T。Cruzi不能合成唾液酸。寄生虫通过一种称为转唾液酸酶的酶从哺乳动物宿主的糖缀合物中清除它。这种酶是一种脱落的毒力因子，诱导宿主免疫系统的改变，有利于寄生虫定植过程。 我们的长期目标是充分阐明这种毒力因子与寄生虫生物学、生命周期毒力和发病机制的相关性，并了解对免疫系统生理学诱导的改变。了解病原体对免疫反应的操纵可以更好地对抗感染，也有助于了解更多关于免疫系统生理学的知识，并最终将这些知识转移到其他病理学（自身免疫性疾病，移植排斥，炎症反应等）的治疗处理中。 该项目旨在揭示寄生虫和淋巴细胞表面上的转唾液酸酶受体分子对唾液酸残基的获取过程在细胞和分子水平上与发病机制和寄生虫生物学的相关性。为了实现这些目标，我们将a）使用用修饰的转运蛋白转染的遗传修饰的寄生虫来准确地确定TS细胞内运输; B）遵循非天然糖方法作为生物正交化学报道分子来清楚地鉴定受体分子及其在寄生虫和白色细胞表面上的命运和功能; c）使用T细胞受体转基因和KO小鼠模型来寻找已知免疫应答的诱导改变;和d）测试遗传修饰的寄生虫以分析TS非活性同种型与毒力因子和发病机理的关联。

DESCRIPTION (provided by applicant): Chagas disease, the American trypanosomiasis, is a chronic disabling parasitic disease caused by the flagellate protozoon Trypanosoma cruzi. It is considered a neglected tropical disease. With an estimated total of 100 million people at risk, about 8-10 million already infected, and about 40,000 new cases/year, Chagas disease represents a major health, social and economic problem in Latin America. The infection is naturally transmitted by triatomine vectors ("kissing bugs"), from the southern USA to the south of South America. However, chagasic patients are in fact dispersed worldwide due to migration from the endemic region to economically-developed countries. Therefore, Chagas disease is emerging in many non-endemic countries (Australia, Japan, Spain, etc). Infected people in Argentina are estimated at about 1,600,000 and in the USA at about 300,000-1,000,000. Although crucial in its life cycle, T. cruzi is unable to synthesize sialic acids. The parasite scavenges it from the mammalian host glycoconjugates through an enzyme known as trans-sialidase. This enzyme is a shed virulence factor that induces alterations in the host immune system, favoring the parasite colonization process. Our long-term aim is to fully clarify the relevance of this virulence factor to parasite biology, life cycle virulence and pathogenesis, and to understand the alterations induced on the immune system physiology. Understanding the manipulation of the immune response by pathogens allows a better fight against the infection and also helps to learn more about the immune system physiology, and eventually to transfer this knowledge to the therapeutic handling of other pathologies (autoimmune diseases, transplant rejection, inflammatory responses, etc.). This project proposes to disclose the relevance -to pathogenesis and parasite biology, at cellular and molecular levels- of the acquisition process of the sialyl residue performed by the trans-sialidase acceptor molecules on the parasite and lymphocyte surfaces. To achieve these goals we will a) use genetically-modified parasites transfected with modified transporters to accurately determine TS intracellular trafficking; b) follow the unnatural sugars approach as bioorthogonal chemical reporters to clearly identify acceptor molecules and their fate and function on parasite and white cell surfaces; c) search for the induced alterations of known immune responses using T-cell receptor transgenic and KO mice models; and d) test genetically-modified parasites to analyze the association of TS inactive isoforms with virulence factors and pathogenesis.