Malarial infections are still one of today's great global health problems, with nearly 600,000 deaths and millions of new infections occurring annually. Plasmodium parasites (the causative agents of malaria) are transmitted between a mosquito vector and their mammalian host, and they have developed intricate systems to adequately prepare for transmission, and to then to firmly establish an infection. Because relatively few parasites are passed between the host and the mosquito vector, these two transmission events have long been prioritized as optimal points for interventions with drugs and vaccines. Recent work has demonstrated that Plasmodium parasites have evolved to use selective translational repression just prior to transmission events to store the mRNAs that it will need for the next steps of development. The adaptation of translational repression for these purposes is a logical choice, as the transmitted gametocytes and sporozoites cannot anticipate when they will be transmitted, and this system allows the parasite to always remain ready for that moment of transmission to occur. While some of the key proteins and mRNAs involved in these events have been identified, many important questions still remain. What proteins are responsible for selecting mRNAs for translational repression? What proteins act to repress them? What attributes of an mRNA will flag it to be selected for translational repression? In this proposed work, we will leverage new technological and experimental approaches to answer these questions, and by doing so, we will better understand the fundamental mechanisms that the parasite has evolved to be efficiently transmitted in both the gametocyte and sporozoite stages. Moreover, we will observe similarities and differences in how the parasite uses translational repression at these two stages in both rodent- infectious, and human-infectious parasites. Taken together, these findings will provide the first mechanistic studies of protein/RNA complexes in sporozoites, will allow a functional comparison across stages and species, and will highlight molecular components and functions that the parasite requires for transmission that may exploited in the future as targets for new therapeutic agents.

Public Health Relevance

Malaria remains one of the great global health problems today, with nearly 600,000 deaths and millions of new infections occurring annually. This research will investigate how the parasite has adapted the use of translational repression of specific mRNAs to become and remain infectious during transmission between the mammalian host and the mosquito vector. Understanding the molecular preparations that the parasite uses to ensure efficient transmission will help us to identify and exploit weaknesses in this crucial step.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI123341-02
Application #
9379447
Study Section
Special Emphasis Panel (ZRG1)
Program Officer
Mcgugan, Glen C
Project Start
2016-11-01
Project End
2021-10-31
Budget Start
2017-11-01
Budget End
2018-10-31
Support Year
2
Fiscal Year
2018
Total Cost
Indirect Cost
Name
Pennsylvania State University
Department
Biochemistry
Type
Schools of Arts and Sciences
DUNS #
003403953
City
University Park
State
PA
Country
United States
Zip Code
16802
Zander, Ryan A; Vijay, Rahul; Pack, Angela D et al. (2017) Th1-like Plasmodium-Specific Memory CD4+ T Cells Support Humoral Immunity. Cell Rep 21:1839-1852
Muñoz, Elyse E; Hart, Kevin J; Walker, Michael P et al. (2017) ALBA4 modulates its stage-specific interactions and specific mRNA fates during Plasmodium yoelii growth and transmission. Mol Microbiol 106:266-284