A high-throughput screening assay based on TR-FRET to identify inhibitors for T. brucei kinases

Abstract

African Sleeping Sickness or Human African Trypanosomiasis (HAT) is one of the most under studied tropical diseases and continues to be a threat to more than 65 million people in sub-Saharan Africa. It is caused by the bite of a tsetse fly infected with a trypanosome known as Trypanosoma brucei. Therapeutic advances have been made in combating the disease, but a high mortality rate of 5%, and the unavailability of treatments for later stages, begets a need for more effective therapeutics. Because kinases are attractive drug targets, we explored the druggability of three Trypanosoma brucei kinases that have been demonstrated to be essential for the survival of the trypanosome, and thus potential drug targets for HAT. Here, we describe a TR-FRET-based assay for the three kinases to identify and confirm inhibitor hits from a kinase inhibitor library of 429 compounds. In our screen, we identified inhibitors belonging to the type II class of kinase inhibitors, with low nanomolar potency (IC50) against several of these three essential kinases. These inhibitors provide new hits for lead optimization with the aim of identifying new drug treatments for HAT.