Malaria is one of the most devastating diseases of humankind, affecting nearly one in ten people worldwide and resulting in over 1.5 million deaths annually. This disease is caused by the Plasmodium parasite, of which Plasmodium falciparum is the deadliest form. While the past century has seen significant progress in anti-malarial drug development, many of these drugs are losing efficacy due to the rise of drug-resistant parasites. One of the major challenges facing the field is the identification of new drug targets for efficacious, affordable treatment. My lab focuses on transcriptional regulation and metabolism as potential avenues to disrupt the progression of this deadly parasite. To accomplish this, our research combines tools from functional genomics, molecular biology, computational biology, biochemistry, and metabolomics to understand the fundamental molecular mechanisms underlying the development of this parasite. The focus is predominantly on the red blood cell stage of development, which is the stage in which all of the clinical manifestations of the malaria disease occur.
Transcriptional regulation in malaria parasites:
My lab is interested in role of transcriptional regulation in parasite development. To study this, we focus on the only known family of DNA binding proteins encoded by the Plasmodium genome, the Apicomplexan AP2 (ApiAP2) protein family. These proteins are highly conserved among all Apicomplexan parasites and find their origin in plants. (Why is there a plant connection you ask? Intriguingly, malaria parasites contain an amazing non-photosynthetic chloroplast-like organelle called the apicoplast which was acquired via a secondary endosymbiotic event so there are many features of plant cells in these intriguing single celled eukaryotic parasites!) To address the specific in vivo roles for the 27 members of the ApiAP2 protein family, we are pursuing several lines of inquiry. These approaches include modulating expression levels of these proteins, generating knockdowns and knockouts, as well as in vivo protein tagging for chromatin immunoprecipitation. We are also using luciferase reporter assays to measure the stage-specificity of expression controlled by the identified target DNA motifs, and we are using mass spectrometry-based proteomics to determine protein-protein interactions for these transcriptional regulatory complexes. Our goal is to define the dynamic transcriptional regulatory network of the malaria parasite and to determine which ApiAP2 proteins are the master regulators governing the various stages of parasite development including the blood stage, the mosquito stage and the liver stage with the goal of targeting these proteins as a way to kill parasites.
The genome of Plasmodium falciparum indicates that the metabolic pathways utilized by this organism are highly unique. Recent efforts to comprehensively examine the biology of P. falciparum have focused on transcriptome and proteome analysis to gain insight into Plasmodium-specific pathways. The third crucial component that remains to be established is the metabolome: the complement of small-molecule metabolites and their relative levels. Our lab has begun to characterize various aspects of parasite metabolism using high accuracy mass-spectrometry to simultaneously measure metabolites from complex cellular extracts from parasite-infected cells. The approaches we are using allow us to assay various aspects of the P. falciparum metabolome. One approach has been to examine the interaction of Plasmodium with the host red blood cell using targeted measurements of specific metabolites shared with the host erythrocyte and asking how these vary when parasites are stressed or exposed to antimalarial drugs. We are also using 13C and 15N isotopic labeling experiments to directly trace carbon flux through known biochemical pathways. Finally, we are using metabolite measurements to map genetic control of metabolism by assaying global metabolite patterns in the parents and progeny of a Plasmodium falciparum genetic cross. Results from these studies are beginning to unravel the divergence of metabolism in P. falciparum and promise to provide unique avenues for future drug intervention strategies.