KSEF RDE: Exploiting autophagy for drug discovery in Apicomplexan parasites

Harnessing programmed cell death (PCD) to promote the killing of pathogens presents a new class of targets for drug discovery. Work in our laboratory, has established an autophagy-related pathway as the primary mechanism of PCD in the parasite Toxoplasma gondii. Collaborative studies indicate autophagy as being important in both drug sensitivity and resistance in malaria. A key hallmark of autophagy mediated death in T. gondii is the selective fragmentation of the single parasite mitochondrion. This unique mechanism of death can be leveraged by the development of medium and high thruput screening platforms focused on the detection of the loss of mitochondrial integrity a marker for progression to death. We propose to implement recent advances in T. gondii molecular biology to develop specific strains with mitochondrial reporters and test their effectiveness using drugs targeting PI3 Kinases known to impact the autophagic cascade. We focus on this pathway due to complementary studies in malaria parasites where as yet unpublished compounds reveal unique synergies with current treatments. These unique compounds are available from our collaborator. Specifically we propose to screen both established and novel compounds predicted to target PI3K’s for their effects on Toxoplasma growth and killing. We will harness state of the art approaches to generate parasite mutants that are resistant to the “lead” compound based on our novel screen. Identification of the presumed target leading resistance will be achieved and confirmed by whole genome sequencing. The implementation of an autophagy-targeting drug screening program will provide leads for new drugs not only in Toxoplasma but also Plasmodium, the malaria parasite, a related Apicomplexan. As a new approach to the identification of drug targets using a novel screening paradigm we will integrate both emerging concepts and technologies toward potential downstream commercial application.