COMPARATIVE GENOMICS OF PARASITIC NEMATODES

Washington University, Saint Louis MO

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Abstract

Comparative Genomics of Parasitic Nematodes Summary Parasitic nematodes infect over two billion people, causing mortality and significant morbidity in humans. Characterization of their genomes provides fundamental molecular information essential for accelerating basic and translational research, which is a public health priority due to the limited number of currently available drugs, their limited efficacy against some species and increasing drug resistance. Our long-term goal is to facilitate the discovery and development of novel interventions to treat and control these important parasites. Progress to date has established an extensive omics database for nematode parasites of medical importance, including human parasites spanning the major taxonomic clades of Nematoda. Using systems biology and evolutionary principles we reconstructed metabolic networks for diverse nematode parasites and discovered phylogenetically restricted and conserved metabolic functions. These results led to our central hypothesis that compounds targeting pan-phylum conserved metabolic chokepoint enzymes have a high potential for broad control despite the parasites' diverse modes of parasitism; which is important since concomitant infection is prevalent in endemic areas. To test this, we have identified conserved targets and compounds with broad-spectrum control potential. Phenotypic screening of parasites at the extremes of the phylogeny validated our predictions. Finally, we established a database of nematode-specific molecular features among the chokepoint enzyme targets and experimentally demonstrated that active-site differences support the feasibility of developing selective inhibitors. Our proposed aims build on our significant progress by taking advantage of and further improving our multi-dimensional resources (Aim 1) to close the gap between omics research and actionable drug discovery. Leveraging the parasite specific active-site features, we will use rational design and medicinal chemistry to optimize the lead inhibitors of the three identified target classes (Aim 2). The four compounds most effective in hookworm in vitro will be screened in vivo, followed by optimization including testing various pharmacokinetic modifications for enhanced efficacy and persistence (Aim 3). Furthermore, since major intestinal nematodes have migratory transpulmonary stages that cause pathological lung lesions, we will test efficacy of the leads against early parasitic stages, which is essential to reducing this irreversible morbidity. Finally, we will expand our primary lead compound screen to demonstrate pan-hookworm and pan-intestinal potential (Aim 4). This contribution is significant since the progress fills the knowledge gap in metabolic functions essential for survival of these parasites. The rational targeting of metabolic chokepoint enzymes as anthelminthic agents is thoroughly novel, as is the concept of utilizing a specific pan-phylum conserved target to develop a single anthelmintic with broad spectrum efficacy against nematodes at large. Collectively, our proposed research has the potential to provide practical results for global health improvement.