DEXES · Mechanisms of dormancy, activation and sexual conversion in pre-erythrocytic malaria parasites

Malaria remains a devastating public health burden the estimated death toll in 2020 was over 600,000. Its eradication is a desirable goal; however, the development of novel intervention strategies is hampered by limited current understanding of the biology of Plasmodium, the causative agent of malaria, and of its complex interactions with mammalian and mosquito hosts. In the liver, inside hepatocytes, Plasmodium parasites can either 1) replicate, forming new parasites that will infect erythrocytes and cause disease, or 2) remain dormant, which can lead to chronic, relapsing disease weeks to years after the original infection. I recently discovered new hepatic outcomes using a novel pipeline for single-cell hepatocyte-pathogen sequencing. I have identified sub-populations of sexually committed parasite forms, previously thought to appear only during erythrocytic infection. This groundbreaking insight into the Plasmodium life cycle can change our understanding of malaria transmission, yet it remains unknown how malaria parasites commit to these different developmental outcomes in hepatocytes.DEXES will test the hypothesis that Plasmodium liver infection outcomes depend upon the metabolic state of the host hepatocyte. Using engineered human microlivers, new humanized mouse models, trans-species studies and single-cell technologies, I will: 1) identify parasite-encoded molecular mechanisms implicated in the induction and maintenance of dormancy, activation, and sexual conversion in the liver, and 2) establish the bidirectional relationships between host metabolism and distinct parasite cell fates and their impact on treatment outcomes. This project will uncover the molecular mechanisms underpinning dormancy, relapsing and transmission of malaria parasites, and lay the groundwork for the future development of new therapies targeting the liver infection reservoirs.