Research Projects

One of the major challenges in controlling malaria is the emergence of resistance against most antimalarial drugs, including artemisinin-based combination therapy (ACT). Parasites with mutations in PfKelch13 (K13), an essential protein which acts as a substrate adaptor for E3 ubiquitin ligase, emerged as the major marker for artemisinin (ART) resistance. K13 mutant parasites are reported to have reduced hemoglobin endocytosis, slow growth, damaged cellular components and heightened stress response such as unfolded protein response and oxidative stress. However, recently, several studies have reported the emergence of K13-independent ART resistance from central India and Africa. The enhanced lipid metabolism, intracellular trafficking of PI3P-rich vesicles, stress responsiveness and transcriptional heterogeneity have emerged as important determinants for K13-independent ART resistance. A large scale genomic analysis from our group has also identified mutations in an α-ß hydrolase (ABH), lipase enzyme with potential role in PI3P pathways and a HECT domain-containing protein (a putative ubiquitin ligase) genes. Taken together, it suggests that genes involved in ubiquitination (including K13) and vesicular transport play an important role in ART resistance. Importantly, while mutations in the K13 are strongly associated with ART resistance, they do not confer sterile resistance. Rather, a small percentage of the ring-stage parasite population shows persistence/dormancy and exhibit recrudescence. The factors enabling persister formation and their connection to ubiquitination (including K13) and vesiculation remain unclear. In this study, we propose to study ART resistance by systematically characterizing persister population of P. falciparum, in the context of ubiquitin and lipid metabolising enzymes like K13, HECT and ABH, with the use of nascent RNA sequencing (using BrU/4s-U labelling) and single-cell RNA sequencing, proximity labelling and lipid profiling. The findings from this study will enhance our understanding of the role of the persister population in generating resistance to ART and identify the molecular markers of dormancy and recrudescence, which can be targeted for future drug development against the ART- resistant parasites.