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

引起人类疟疾的间日疟原虫在地理上是所有寄生虫中分布最广的 疟原虫的物种。间日疟原虫是亚洲、大洋洲、 中美洲和南美洲，以及非洲之角。在这些地区，孕妇感染间日疟原虫 妇女对早孕丢失、新生儿体重减轻和婴儿死亡率有显著贡献。值得注意的是，P. 由于其独特的生物学特性，间日疟是根除疟疾领域的一个主要问题。具体来说，间日疟原虫 肝细胞的子孢子感染并不总是导致分裂的发生和向血液的转变 阶段性疾病，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 重新启动。这种休眠或潜伏的肝脏阶段形式被称为催眠体，并在继续努力 在消灭和根除疟疾方面，催眠虫是一个强大的敌人。事实上，P. 遍及热带和温带气候区的间日疟原虫可归因于这种寄生虫形成的能力 催眠药在重新激活后，可防止血液期感染和伴随传播的复发。 抗疟疾药物几乎只针对生命周期的症状性血液阶段，而不针对 催眠药和用标准药物方案治疗间日疟原虫血液期感染允许 进一步复发，将无助于根除疾病。 从历史上看，唯一被批准的对抗间日疟原虫催眠虫的药物是伯喹，尽管一种 改良的8-氨基喹啉药物他非诺喹最近获得批准用于治疗复发 疟疾。不幸的是，伯氨喹的半衰期短，剂量方案长，与葡萄糖-6不相容- 磷酸脱氢酶缺乏，阻止其用于大规模消除运动。因此，有一个 需要新的干预措施，对催眠素的形成、存活和复发产生负面影响。因此， 这项提议的研究旨在提供对催眠虫的生物学见解。此应用程序旨在解决 关于间日疟原虫催眠体生物学的三个关键生物学问题及其回答 应有助于发现新的干预措施，以防止催眠药复发和持续传播催眠药 间日疟原虫病。 具体地说，间日疟原虫子孢子中有没有预先编程的内在因素 一旦它到达肝脏，决定它的命运，成为复制的裂殖体或休眠的催眠体？ 休眠的催眠虫如何操纵其宿主细胞以维持其长期驻留？能 我们开发了催眠药复发的模型，以深入了解催眠药复发的诱因。 重新激活？使用人-肝嵌合小鼠模型和创新的单细胞方法 分离和转录图谱，我们希望能够应对这些挑战。

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.