Understanding and manipulating how Trypanosoma cruzi infects its triatomine insect hosts

恰加斯病，又称美洲锥虫病，每年造成大约1万人死亡。它是由原生寄生虫克氏锥虫引起的。据估计，全世界有600万至700万人感染克氏锥虫，但尽管人数众多，恰加斯病是一种被忽视的热带病，目前还没有成功的疫苗。该疾病在21个拉丁美洲大陆国家流行，主要是当人类接触受感染的吸血三角蝽虫的粪便和/或尿液时传播，主要是长角Rhodnius和Triatoma infestans（媒介传播）。我们知道寄生虫利用各种机制来逃避哺乳动物宿主的免疫系统，包括产生称为脂质介质的信号分子，用于抑制宿主的免疫反应。然而，寄生虫是如何在昆虫宿主体内扎根的还没有被阐明。我们的初步数据表明，由昆虫感染形式的寄生虫产生的脂质介质可能起着至关重要的作用，探索这是当前建议的重点。我们将鉴定这些脂质介质并研究它们如何调节昆虫免疫。一个关键的步骤是感染的初始阶段，当寄生虫在昆虫的肠道中建立自己。相互竞争的肠道细菌为寄生虫创造了一个不利的环境。为了解决这个问题，寄生虫入侵昆虫的免疫系统，使昆虫产生抗菌蛋白，减少肠道内的细菌数量。在BBSRC的支持下，我们之前开发了一项新技术并获得了专利，该技术可以重新利用这些昆虫的肠道细菌，使它们不断产生可以沉默昆虫宿主特定基因的遗传信息。我们现在打算将这项技术应用于昆虫免疫系统是如何被调节的。我们的目标是利用这一点来对抗寄生虫如何攻击昆虫的免疫反应。如果成功，这种方法将减少昆虫体内的寄生虫数量，从而降低病媒传播疾病的几率。该项目将证明这种方法是否有潜力作为我们应对与气候变化相关的病媒传播增加的反应的一部分。

Chagas disease, also known as American trypanosomiasis, results in approximately 10,000 deaths annually. It is caused by the protozoan parasite Trypanosoma cruzi. An estimated 6 to 7 million people worldwide are infected with T. cruzi but, despite these large numbers, Chagas disease is a neglected tropical disease for which there are no successful vaccines. The disease is endemic to 21 continental Latin American countries and is mostly transmitted when humans come into contact with faeces and/or urine of infected blood-sucking triatomine bugs, primarily Rhodnius prolixus and Triatoma infestans (vector-borne transmission). We know that the parasite utilises various mechanisms to evade the mammalian host immune system including producing signalling molecules termed lipid mediators that serve to dampen the host immune response. However, just how the parasite establishes itself in the insect host has not been elucidated. Our preliminary data indicates that the production of lipid mediators by insect-infective forms of the parasite likely plays a vital role and exploring this is a focus of the current proposal. We will identify these lipid mediators and investigate how they regulate insect immunity. A critical step is the initial stage of infection, when the parasite establishes itself in the insect gut. Competing gut bacteria create a hostile environment for the parasite. To counter this, the parasite hacks the insect immune system so that the insect produces antimicrobial proteins to reduce the bacterial population in the gut. With BBSRC support, we previously developed and patented a novel technology to repurpose gut bacteria from these insects so that they continuously produce genetic information that can silence specific genes of the insect host. We now intend to apply this technology to target how the insect immune system is regulated. Our goal is to exploit this to counter how the parasite hacks the insect immune response. If successful, this approach will reduce parasite numbers in the insect which will, in turn, lower disease transmission by the vector. The project will demonstrate whether this approach has potential to be used as part of our response to combat climate-change associated increases in vector-borne disease transmission in general.