Malaria threatens approximately 40% of the world population, causing 429 000 deaths annually, and the malaria parasite, Plasmodium falciparum, has developed resistance to most approved antimalarials. New ozonide antimalarials (OZs) are now in clinical trials and early clinical usage, but their mechanism of action remains poorly defined. Metabolomics technology offers the opportunity to measure the impact of drug action on cellular metabolism at a system-wide level, allowing unbiased assessment of the key pathways involved in the mechanism of action. The aim of this study was to use metabolomics to reveal the mechanisms of action of OZ antimalarials.

P. falciparum parasites were cultured and treated with OZ antimalarials, followed by metabolomics analysis using LC-MS with high resolution accurate mass spectrometry. The untargeted metabolomics analysis of drug-treated parasites revealed depletion of specific small peptides, and the kinetics of peptide depletion corresponded with the onset of action of each compound. A dedicated peptidomics method was developed, which revealed drug-induced perturbation to haemoglobin digestion in agreement with the proposal that OZs are activated in the digestive vacuole of the parasite. Additional pathways involved in lipid and nucleotide synthesis were also perturbed with prolonged OZ exposure, and comparative proteomics analysis confirmed the dysregulation of these pathways. This unbiased multi-omics approach revealed an initial impact of OZ antimalarials on haemoglobin digestion, followed by secondary inhibition of additional pathways that are essential for parasite survival and replication.

Video from the Keynote Speaker Dr. Darren Creek can be found as below: