Metabolism and drug resistance probed with new genetic tools in the neglected animal pathogen Trypanosoma vivax.

非洲动物锥虫病（AAT）是一种使牛和其他牲畜衰弱的疾病，主要由两种单细胞寄生虫引起：刚果锥虫和间日锥虫。每年约有7000万例AAT病例，造成约300万人死亡，并给农村社区造成巨大的经济负担。除了在非洲引起疾病外，间日疟原虫还蔓延到南美洲，在那里它是一个日益严重的问题。尽管间日疟原虫是一种全球重要的病原体，但在知识和研究工作方面却被严重忽视，这主要是由于缺乏良好的系统来维持动物外的寄生虫或调查其个体基因的功能。间日疟原虫在遗传上不同于研究得更好的锥虫，大约三分之一的间日疟原虫基因没有在相关物种中发现——这反映在这种寄生虫生物学的重要差异上，包括它通过昆虫媒介传播、逃避宿主免疫系统以及对药物的耐药性。需要提高基础知识和实验室能力，以转变有效处理间日疟原虫的能力，并设计工具，从而减少AAT的影响。这个项目将两者兼顾；通过在间日疟原虫生物学关键领域产生新的知识，并开发用于培养和遗传转化寄生虫的工具包。我们将通过分析基因表达模式和寄生虫使用/产生的化学物质来描述间日疟原虫的核心代谢特征。这将使我们能够确定间日疟原虫细胞内发生的化学过程，我们将用靶向化学抑制剂和干扰特定基因的表达来测试这些预测。我们还将描述间日疟原虫表面的蛋白质，这些蛋白质是细胞与宿主直接接触的部分，包括那些负责关键代谢物和药物摄取的部分。我们将产生对三种药物（目前在该领域广泛使用的两种药物和临床开发中的一种药物）具有耐药性的寄生虫，并确定导致耐药性的遗传变化。通过将这些信息与间日疟原虫的代谢、表面组成和其他锥虫的功能研究数据进行比较，我们将首次解码间日疟原虫的耐药机制。最后，我们的目标是开发关键的间日疟原虫实验室资源。关于寄生虫代谢和表面补体的信息将用于设计化学配方，以支持间日疟原虫在动物体外的生长，就像对其他锥虫所做的那样。我们还将开发间日疟原虫的遗传工具包，以便对其基因进行功能分析，这将直接有助于我们了解代谢和耐药性的目标。该项目将以该团队的相关专业知识为基础，该团队在成功解决相关寄生虫布氏弓形虫和刚果弓形虫的类似问题方面具有经验，并将补充我们的工业合作伙伴全球畜牧兽医联盟（GALVmed）的药物开发工作。产出将与药物开发和药物可持续性特别相关——了解对现有药物和新药的耐药性可以使药物使用的知情设计能够最大限度地延长治疗的寿命。此外，提高我们对核心代谢的认识有可能确定新的药物靶点，培养间日疟原虫的能力将使药物发现工作的规模扩大。因此，实现这些目标将改变我们与间日疟原虫合作的能力，产生基础知识和数据集，并推进这一被严重忽视的病原体的基础和应用研究能力。

Animal African Trypanosomiasis (AAT) is a debilitating disease of cattle and other livestock, caused mainly by two species of single-celled parasite: Trypanosoma congolense and Trypanosoma vivax. There are ~70 million cases of AAT each year, causing ~3 million deaths and creating a great economic burden on rural communities. As well as causing disease in Africa, T. vivax has also spread to South America, where it is an increasing problem. Despite being a globally important pathogen, T. vivax is severely neglected in terms of knowledge and research effort - due largely to the lack of good systems in place for maintaining the parasite outside of animals or for investigating the function of its individual genes. T. vivax is genetically distinct from better-studied trypanosomes, with around one third of all T. vivax genes not being found in related species - this is mirrored in important differences in the biology of the parasite, including its transmission through the insect vector, evasion of the host immune system, and its resistance to drugs. Advancement of both fundamental knowledge and laboratory capabilities are needed to transform the ability to work meaningfully with T. vivax , and to design tools to consequently reduce the impact of AAT. This project will do both; by generating new knowledge on key areas of T. vivax biology and developing a toolkit for culturing and genetic transformation of the parasite.We will characterise the core metabolism of T. vivax by analysing the pattern of gene expression and what chemicals the parasites use/produce. This will enable us to define the chemical processes going on inside T. vivax cells, and we will test these predictions with targeted chemical inhibitors and interfering with expression of specific genes. We will also characterise the proteins on the surface of T. vivax, which are the parts of the cell in direct contact with the host, including those responsible for key metabolite and drug uptake. We will generate parasites resistant to three drugs (the two drugs currently widely used in the field, and one in clinical development) and identify genetic changes responsible for resistance. By comparing these to information on T. vivax metabolism, surface composition, and data from functional studies in other trypanosomes, we will decode mechanisms of drug resistance in T. vivax for the first time. Finally, we aim to develop critical laboratory resources for T. vivax. Information on parasite metabolism and surface complement will be used to design chemical formulations that will support growth of T. vivax outside of animals, as has been done for other trypanosomes. We will also develop a genetic toolkit for T. vivax to enable functional analysis of its genes, which will feed directly into our aims of understanding of metabolism and drug resistance. The project will build upon relevant expertise of the team, who have experience in successfully tackling similar questions for the related parasites T. brucei and T. congolense, and complements the drug development efforts of our industrial partner, the Global Alliance for Livestock Veterinary Medicines (GALVmed). The outputs will be particularly relevant to drug development and drug sustainability - understanding drug resistance to existing and new drugs enables informed design of drug usage that can maximise the lifetime of treatments. Additionally, advancing our knowledge of core metabolism has the potential to identify novel drug targets, and the ability to culture T. vivax would enable the scaling up of drug discovery efforts. Therefore, achieving these aims will transform our ability to work with T. vivax, generating foundational knowledge and datasets, and advancing fundamental and applied research capabilities for this significantly neglected pathogen.