Poster Presentation First Malaria World Congress 2018

Revealing the biochemical pathways targeted by peroxide antimalarials in 3D7 and K13-mutant artemisinin-resistant Plasmodium falciparum with metabolomics and proteomics (#290)

Carlo Giannangelo 1 , Ghizal Siddiqui 1 , Susan A Charman 1 , Darren J Creek 1
  1. Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria, Australia

Peroxide antimalarials, including artemisinins and ozonides, are active against all blood-stages of the malaria parasite Plasmodium falciparum. The literature indicates that reductive activation within the parasite generates drug-derived radicals that alkylate and cause oxidative damage to various intraparasitic components. This study used a multi-omics-based approach to map the biochemical pathways affected by the ozonides, OZ277 and OZ439, and dihydroartemisinin (DHA), within P. falciparum, and to investigate the differential biochemical response of paired K13-mutant artemisinin resistant (Cam3.IIR539T) and K13-wildtype artemisinin sensitive (Cam3.IIrev) parasites to peroxide exposure.

The major pathway initially affected by peroxide exposure (up to 3 h) was haemoglobin catabolism. Metabolomics analysis revealed depletion of haemoglobin-derived small peptides, and the formation of alkylated haem adducts. Extended treatment durations induced perturbations to additional biochemical pathways including, lipid, pyrimidine and amino acid metabolism. Peptidomic studies confirmed changes to haemoglobin-derived peptides, and activity-based protease probes demonstrated changes in haemoglobin protease activity within 1 h of drug exposure. Peroxides also induced perturbation to haemoglobin-derived peptides in K13-resistant and sensitive parasites, although the impact was less pronounced in the resistant line and this was associated with enhanced antioxidant capacity. In general, the peptides that were depleted following peroxide exposure were initially more abundant in untreated resistant parasites compared with sensitive, further emphasising the importance of haemoglobin catabolism in peroxide activity.

At the proteome level, the major impact of peroxide exposure was upregulation of proteins involved in translational regulation and the ubiquitin-proteasome system, indicative of a generalised stress response to mitigate peroxide-induced damage.

These data demonstrate a central role for the haemoglobin digestion and stress response pathways in the activity and resistance mechanisms for peroxide antimalarials, which provides new opportunities for interventions to enhance peroxide antimalarial efficacy and limit the impact of drug resistance.