The long-term goal of this project is to develop a new class of safe and effective anti-malarial drugs to combat the emergence of resistance to existing treatment of Plasmodium falciparum infection. Our immediate objective is to discover novel small molecular inhibitors of the P. falciparum facilitative glucose transporter PfHT that can be used for subsequent lead optimization studies. Central to our strategy is the identification of compounds with selectivity for the plasmodium transporter over human facilitative glucose transporters (GLUTs). Based upon our established success in elucidating the structural basis for the effects of antiretroviral drugs in clinical use toward human GLUTs and knowledge of sequence homologies between parasite and human orthologues, we hypothesize that PfHT antagonists with high affinity and selectivity for this transporter can be identified. To test this hypothesis, we will utilize a high throughput screening approach combined with hit validation and in vitro testing for compound effects on human GLUTs. Inhibitor screening will be accomplished using a novel cell based assay that uses a FRET-based signal to detect changes in intracellular glucose levels. Hit compound selectivity for PfHT over human GLUT orthologues will be assessed in our unique HEK293 cell lines that over-express individual glucose transporters. Target validation will be performed in blood stage P. falciparum with measurement of compound effects on 2-deoxyglucose transport rates, parasite growth, and with resistance profiling. Taken together, this project will provide a solid foundation for subsequent in-depth characterization of lead compound structure-activity relationships, candidate drug optimization, and eventual human clinical trials.
Malaria remains a major cause of illness and death. Resistance of Plasmodium falciparum, the parasite responsible for the majority of malaria cases worldwide, to all existing drugs is a growing public health problem and new treatments are urgently needed. This project seeks to discover a new class of drugs that target PfHT, a key protein necessary for entry of the sugar glucose into the parasite, without affecting the human glucose transporters.