tRNA modification reprogramming in artemisinin-resistant Plasmodium falciparum: An epigenetic driver of resistance?

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PROJECT SUMMARY / ABSTRACT: Rationale: The spread of artemisinin (ART)-resistant Plasmodium falciparum (Pf) strains across Asia and their recent emergence in Africa and South America imperils efforts to treat and control malaria. ART resistance is mediated primarily by mutations in Pf K13, which reduce drug activation by decreasing hemoglobin endocytosis and which initiate quiescence during peak drug levels. Our preliminary data have uncovered a role for tRNA modification reprogramming and proteomic changes in mutant K13 parasites exposed to ART pressure. In this mentored career project, we hypothesize that quiescence is epigenetically regulated by reprogramming tRNA modifications, which leverage codon-biased translation to alter the parasite proteome and enable the survival of ART-treated mutant K13 parasites. Candidate: As an Infectious Diseases physician with a PhD in Microbiology and Immunology, I am uniquely positioned to bridge biomedical research and patient care to understand the molecular mechanisms that Pf employs to survive ART treatment. Further training in molecular parasitology, mass spectrometry, proteomics, RNA biology, and epigenetics will be crucial for my development into an independent academic physician-scientist specializing in Pf stress responses and drug resistance. I have a renowned mentor in Dr. David Fidock and benefit from an outstanding multi- disciplinary team of experts to guide my training and research progress. Environment: The Fidock laboratory at the Columbia University Irving Medical Center (CUIMC) has been a pioneer in applying genetic and multi-omic tools to explore Pf resistance to ART and other drugs. This enriching environment also provides access to multiple isogenic k13-edited Pf lines and a large network of collaborators including experts in mass spectrometry- based tRNA modifications, proteomics, and codon-biased translation. CUIMC also has a long track record of enabling young physician-scientists to develop independent and successful careers in academic medicine. Approach: Our central hypothesis is that tRNA modification reprogramming, specifically the s2U modification, is central to how parasites achieve ART resistance by altering their proteome and regulating entry into and exit from drug-induced quiescence. In Aim 1, we will elucidate the kinetics of tRNA modification reprogramming in isogenic ART-resistant and ART-sensitive parasites across a panel of K13 variants and genetic backgrounds. In Aim 2, we will apply conditional knockdown approaches to explore the role of the s2U pathway in ART resistance and parasite survival. In Aim 3, we will test the complementary hypothesis that modifications on the amino-acyl tRNA regulate ART-mediated quiescence. This proposal provides an innovative approach to examining how K13 mutations achieve ART resistance via epigenetic changes that reprogram tRNA modifications to alter translational and proteomic responses to ART pressure. If confirmed experimentally, these hypotheses will set a new paradigm for how Pf can modulate its biology to survive drug-mediated cellular stress. Our results should also identify parasite vulnerabilities that can be leveraged into new strategies to treat ART-resistant malaria.