Uncovering the parasite and host determinants of Plasmodium vivax hypnozoite formation and development using single cell sequencing and human liver-chimeric mice

引起人类疟疾的寄生虫间日疟原虫是地理上分布最广的寄生虫 疟原虫种类。间日疟原虫是亚洲、大洋洲流行地区发病的主要原因。 中南美洲以及非洲之角。在这些地区，孕妇间日疟原虫感染 妇女对早孕流产、出生体重和婴儿死亡率的降低有重大影响。值得注意的是，P. 由于其独特的生物学特性，间日疟原虫是消除疟疾领域的一个主要关注点。具体来说，间日疟原虫 肝细胞的子孢子感染性并不总是导致分裂发生并转化为血液 阶段疾病，如恶性疟原虫的情况。相反，子孢子可以进入宿主肝细胞， 去分化，然后在宿主肝细胞内休眠数周、数月甚至数年，然后 重新激活。这种休眠或潜伏的肝脏阶段形式被称为休眠子，并正在持续努力中 对于消除和根除疟疾来说，催眠体是一个可怕的敌人。事实上，P 的流行性。 整个热带和温带气候区的间日疟原虫归因于寄生虫形成的能力 休眠子，重新激活后，血液阶段感染复发并伴随传播。 抗疟药几乎专门针对生命周期的有症状的血液阶段，而不是针对 催眠体，因此用标准药物方案治疗间日疟原虫血期感染可以 进一步复发，无助于疾病的根除。 从历史上看，唯一批准的针对间日疟原虫催眠子的药物是伯氨喹，尽管 改进的 8-氨基喹啉药物他非诺喹最近获得批准用于治疗复发性 疟疾。不幸的是，伯氨喹的半衰期短、剂量方案长且与葡萄糖-6-不相容。 磷酸脱氢酶缺乏症，阻止其用于大规模消除活动。因此，有一个 需要新的干预措施来对催眠体的形成、存活和复发产生负面影响。因此， 该提案中的研究旨在揭示催眠体的生物学见解。该应用程序旨在解决 与间日疟原虫休眠子生物学有关的三个关键生物学问题以及回答这些问题 应该有助于发现新的干预措施，以防止催眠体复发和继续传播 间日疟原虫病。 具体来说，间日疟原虫子孢子中是否存在预先编程的内在因素， 一旦它到达肝脏成为复制的裂殖体或休眠的催眠体，就决定了它的命运吗？ 休眠的催眠体如何操纵其宿主细胞以维持其长期驻留？可以 我们开发了一个催眠复发模型，以便深入了解促进催眠的触发因素 重新激活？使用人肝嵌合小鼠模型以及单细胞创新方法 分离和转录分析，我们希望能够解决这些挑战。

The human malaria-causing parasite Plasmodium vivax is geographically the most widespread of all the Plasmodium species. P. vivax is a major cause of morbidity in endemic regions of Asia, Oceania, Central and South America, as well as the horn of Africa. In these regions, P. vivax infections in pregnant women significantly contribute to early pregnancy loss, reduced birth weight and infant mortality. Notably, P. vivax is a major concern in an arena of malaria eradication due to its unique biology. Specifically, P. vivax sporozoite infectivity of hepatocytes does not always lead to the onset of schizogony and transition to blood stage disease, as is the case for P. falciparum. Rather, a sporozoite can enter a host hepatocyte, dedifferentiate and then lie dormant within the host hepatocyte for weeks, months or even years, before reactivating. This dormant or latent liver stage form is known as the hypnozoite and in continued efforts towards malaria elimination and eradication, the hypnozoite is a formidable foe. Indeed, the endemicity of P. vivax throughout tropical as well as temperate climate zones is attributed to the parasite’s ability to form hypnozoites, which after reactivating, case relapses of blood stage infection and concomitant transmission. Antimalarial drugs almost exclusively target the symptomatic blood stage of the life cycle and do not target the hypnozoite and thus treatment of P. vivax blood stage infections with standard drug regimens allows for further relapses and will not aid in disease eradication. Historically, the only approved drug active against P. vivax hypnozoites was primaquine although an improved 8-aminoquinoline drug, tafenoquine, has recently received approval for the treatment of relapsing malaria. Unfortunately, primaquine’s short half-life, long dosage regimen and incompatibility with glucose-6- phosphate dehydrogenase deficiency, prevent its use for mass elimination campaigns. Thus, there is a need for novel interventions that will negatively affect hypnozoite formation, survival and relapse. Thus, the research in this proposal aims to shed biological insight on the hypnozoite. This application aims to address three critical biological questions pertaining to P. vivax hypnozoite biology and answering these questions should aid in the discovery of novel interventions to prevent hypnozoite relapse and the continued spread of P. vivax disease. Specifically, are there intrinsic factors that are pre-programmed in the P. vivax sporozoite that determine its fate once it reaches the liver to become either a replicating schizont or a dormant hypnozoite? How does the dormant hypnozoite manipulate its host cell in order to maintain its long-term residency? Can we develop a model of hypnozoite relapse in order to gain insight into the triggers that promote hypnozoite reactivation? Using a human-liver chimeric mouse model alongside innovative methods of single cell isolation and transcriptional profiling, we hope to being to address these challenges.