Parasite Genetics and Adaptations - Project B7

Metabolic characterisation and chemotherapeutic targeting of persistent T.gondii and P. falciparum parasites

Host lab: Martin Blume (Robert Koch-Institute, Berlin)

Partner labs: Kai Matuschewski (Dept. of Biology, Humboldt University Berlin), Kevin Saliba (Department Research School of Biology, ANU, Canberra)

Background and Aim: Phenotypic variation in protozoan parasites is an important strategy to evade the immune responses and antimicrobial treatments. The apicomplexans Toxoplasma gondii and Plasmodium falciparum employ this strategy through the formation of tissue cysts and dormant blood stages, respectively [1]. These stages are marked by attenuated growth and drug resistance. The ability to persist facilitates transmission to the next host. In order to successfully target these evasive stages we need to understand how resistance to antimicrobials is achieved. To this end we aim to characterize the metabolism of dormant parasites by using untargeted metabolomics and test their susceptibility to novel inhibitors.

Methods: We use untargeted metabolomics techniques that are based on both liquid and gas chromatography-coupled mass spectrometry to characterize the metabolism of dormant T. gondii and P. falciparum parasites. To this end, both profiling of metabolite levels and stable isotope-resolved flux profiling will be employed. We will use inhibitors and genetic mutants to modulate the activity of metabolic pathways and test their importance to parasites persistence and drug resistance.

Plan:

 1^st and 3^rd year (Berlin)

·         Generation of dormant T. gondii and P. falciparum stages

·         Untargeted metabolomics analyses

·         ¹³C-flux profiling

·         Test a pre-selected set of novel MMV inhibitors against dormant parasites

2^nd year (Canberra)

·         Generation of metabolic mutants in both parasite species

·         Characterization of the viability and drug susceptibility of mutants

References:

1. Barrett MP, Kyle DE, Sibley LD, Radke JB, Tarleton RL (2019) Protozoan persister-like cells and drug treatment failure. Nat Rev Microbiol 17: 607-620.