Elucidating ligand-receptor interactions required for Plasmodium vivax blood-stage infection

项目摘要 间日疟原虫是引起人类疾病的所有疟疾寄生虫中分布最广的，它是 这是相当大的发病率来源，也是根除的一项重大挑战，因为长期存在 肝脏中无症状的催眠药。人们对间日疟原虫感染的生物学了解甚少，这在很大程度上是由于 由于缺乏连续的体外培养系统。间日疟原虫显著地只入侵网织红细胞 血液期感染，最年轻的红血球。间日疟原虫入侵的分子机制 网织红细胞在很大程度上仍不清楚。以前的研究主要集中在单分子相互作用上。 间日疟原虫侵袭配体PvDBP和宿主DARC受体，但现在已知可以发生侵袭 通过独立于DARC的路径。我们假设EBL和RBL家族的其他成员 侵袭配体可能在与特定的网织红细胞受体结合以介导成功的过程中发挥关键作用。 入侵。在这个提议中，我们建立在我们实验室的两个主要进展上？？产生基因的能力。 红细胞中的基因敲除，以及对间日疟原虫进行强大的体外侵袭分析的能力。使用这些 方法：我们已经确定TfR1是RBL蛋白PvRBP2b的受体。我们现在将进行一次 红细胞膜蛋白基因敲除筛选综合鉴定网织红细胞 间日疟原虫入侵所需的膜蛋白，以及2)识别与其结合的关键寄生虫配体 同源红细胞受体，通过询问间日疟原虫EBL和RBL家族的候选成员， 以及对间日疟原虫裂殖子蛋白进行无偏筛选。总之，这些研究将有助于 极大地提高了我们对间日疟原虫与其宿主红血之间的分子相互作用的了解 手机。从长远来看，我们希望我们的研究将提供对基本配体的功能理解- 间日疟原虫入侵所需的受体相互作用，并为疫苗开发和宿主设计提供信息- 靶向治疗。

Project Summary Plasmodium vivax is the most widely distributed of all of the malaria parasites that cause human disease, and is a source of considerable morbidity, and a major challenge for eradication, due to long-term persistence of asymptomatic hypnozoites in the liver. The biology of P. vivax infections is poorly understood, in large part due to the absence of a system for continuous in vitro culture. P. vivax strikingly invade only reticulocytes during blood-stage infections, the youngest of red blood cells. The molecular mechanisms by which P. vivax invade reticulocytes remain largely unknown. Previous research has focused on a single molecular interaction between a P. vivax invasion ligand PvDBP and the host DARC receptor, but it is now known that invasion can occur through pathways independent of DARC. We hypothesize that other members of the EBL and RBL families of invasion ligands are likely to play a key role in binding to specific reticulocyte receptors to mediate successful invasion. In this proposal, we build upon two major advances in our laboratory- the ability to generate gene knockouts in red blood cells, and the ability to perform robust in vitro invasion assays with P. vivax. Using these approaches, we have identified TfR1 as the receptor for the RBL protein PvRBP2b. We will now 1) conduct a genetic knockout screen of red blood cell membrane proteins to comprehensively identify all of the reticulocyte membrane proteins that are required for P. vivax invasion, and 2) identify key parasite ligands that bind to their cognate red blood cell receptors, by interrogating candidate members of the EBL and RBL families in P. vivax, as well as conducting an unbiased screen of P. vivax merozoite proteins. Together, these studies will serve to dramatically increase our understanding of the molecular interactions between P. vivax and its host red blood cell. In the long-term we hope that our studies will provide a functional understanding of the essential ligand- receptor interactions required for P. vivax invasion, and inform vaccine development and the design of host- targeted therapeutics.