Exploring the adaptive role of genomic instability in Trypanosoma cruzi.

克氏锥虫是一种引起恰加斯病的原生动物，恰加斯病是一种致命的寄生虫病，由一种叫做接吻虫的昆虫传播。T.克鲁兹在拉丁美洲感染了700万人，1700万人被认为有感染的危险。受感染者向欧洲和北美的迁移使查加斯病超出了其传统范围，在全球范围内增加了约50万例。在欧洲和美洲，存在先天性和输血传播的风险，受感染的个人对公共卫生服务构成重大挑战。查加斯病是拉丁美洲最重要的寄生虫病，每年造成12，000人死亡。为了提供背景，该区域的疟疾死亡人数只是其中的一小部分（每年200-400人）。感染猫弓首蛔虫南美锥虫病患者的cruzi是终身的。药物治疗是有限的，往往在清除寄生虫感染无效，几乎总是在缓解衰弱的慢性症状（心脏病，胃肠道异常）无效。尽管查加斯病对人类健康的影响，但与其他相关的人类寄生虫- T相比，对其生物学知之甚少。布鲁氏菌（昏睡病的病原体）和利什曼原虫（利什曼病的病原体）。重要的知识差距存在围绕如何T。cruzi适应环境压力。解决这些差距可以揭示寄生虫如何避免宿主免疫力在其宿主中建立持续感染，以及它如何在药物治疗中生存。DNA序列测定表明，T.由我们的联合体成员和其他人分离的cruzi分离物揭示了处于不断重排状态的基因组。对T.根据我们现在提供的试验数据，在密切相关的分离株之间，以及在不同时间点取样的个体人类感染中，克氏染色体可能存在很大差异。这种基因组重排的适应性价值可能是理解和解决T。克鲁兹生物学在这项提案中，我们利用基因组学、遗传操作、动物疾病模型以及世界一流的研究团队的进步来了解T。cruzi基因组重排可能是哺乳动物宿主中长期存活以及寄生虫对一线和下一代药物的耐药性的基础。利用单细胞基因组学，我们将把基因组重排与耐药性联系起来，然后通过遗传操作，试图中断使这种重排发生的机制。然后，我们将进行一系列深入的实验，将寄生虫基因组重排与小鼠模型中免疫压力下的生存联系起来，并通过对厄瓜多尔恰加斯病患者队列的观察来证实这些。在哺乳动物中的实验将集中在寄生虫细胞表面表达的基因家族之间的重新排列。寄生虫基因组变化的时间动态免疫功能正常的主机将被跟踪和比较，在没有一个功能正常的免疫系统，以检测通过抗原转移免疫回避的签名。本研究计划中提出的实验是重要的基础科学的先驱，以改善药物设计和未来的T。cruzi疫苗的开发，最终改善了数百万南美锥虫病患者的健康状况。

Trypanosoma cruzi is a protozoan that causes Chagas disease, a fatal parasitic disease spread by an insect vector called a kissing bug. T. cruzi infects seven million people in Latin America and seventeen million are thought to be at risk of infection. Migration of infected individuals to Europe and North America has transferred Chagas disease outside its traditional range, accounting for c.500,000 additional cases globally. In Europe and America, a risk of congenital and transfusional transmission exists, and infected individuals represent a significant challenge for public health services. Chagas disease is the most important parasitic in Latin America, killing 12,000 people every year. To provide context, malaria in the region kills a fraction of that number (200-400 annually). Infection with T. cruzi in Chagas disease patients is life-long. Drug treatments are limited, often ineffective at clearing parasite infection, and almost always ineffective at alleviating debilitating chronic symptoms (heart disease, GI tract abnormalities). Despite the impact of Chagas disease on human health, relatively little is known about its biology by comparison to other related human parasites - T. brucei (agent of sleeping sickness) and Leishmania (agent of Leishmaniasis). Important knowledge gaps exist around how T. cruzi adapts to environmental stressors. Addressing theses gaps could shed light on how the parasite avoids host immunity to establish persistent infections in its host, as well as how it survives drug treatment. DNA sequencing of T. cruzi isolates by members of our consortium and others reveals a genome in a constant state of re-arrangement. The number, sizes, copy number and composition of T. cruzi chromosomes can vary substantially between closely related isolates, as well as, based on pilot data we now present, from individual human infections sampled at different time points. The adaptive value of such genomic re-arrangements may hold the key to understanding, and addressing, many intractable aspects of T. cruzi biology. In this proposal we leverage advances in genomics, genetic manipulation, animal disease models, as well as a world-class research team to understand how T. cruzi genomic re-arrangements may underpin long term survival in the mammalian host as well as parasite resistance to frontline and next generation drugs. Using single cell genomics, we will link genomic re-arrangements to drug resistance and then, via genetic manipulation, attempt to interrupt the machinery that enables such re-arrangements to occur. We will then undertake a series of incisive experiments to link parasite genomic re-arrangements to survival under immune pressure in mouse models and confirm these via observations in a cohort of Ecuadorian Chagas disease patients. Experiments in mammals will focus on re-arrangements among families of genes expressed on the parasite cell surface. The temporal dynamics of parasite genomic changes within immune-competent hosts will be followed and compared to the those in the absence of a functioning immune system to detect signatures of immune avoidance via antigenic shift.The experiments proposed in this research program are vital basic science precursors to improved drug design and the lab groundwork for future T. cruzi vaccine development, ultimately improving health outcomes for the millions affected by Chagas disease.