Discovering new metabolic pathways in protozoan parasites using stable isotope labelled metabolomics  — ASN Events
  1. Schedule
  2. Lunch & Poster Session One
  3. Discovering new metabolic pathways in protozoan parasites using stable isotope labelled metabolomics 

Discovering new metabolic pathways in protozoan parasites using stable isotope labelled metabolomics  (#121)

Darren J Creek 1 , Rainer Brietling 2 , Malcolm J McConville 3 , Dominique Soldati-Favre 4 , Michael P Barrett 5
  1. Monash University, Parkville, VIC, Australia
  2. University of Manchester, Manchester, UK
  3. Biochemistry and Molecular Biology, University of Melbourne, Melbourne, Vic, Australia
  4. University of Geneva, Geneva, Switzerland
  5. University of Glasgow, Glasgow, UK

Metabolomics is the global measurement of metabolites in a biological system. Established metabolomics methods allow relative quantitation of a broad range of metabolites, providing a snapshot of the metabolic state of the system under investigation. However, these methods do not reveal the connectivity of metabolites or the flux through metabolic pathways. A combination of high resolution untargeted metabolomics with stable-isotope labelling allows a system-wide analysis of metabolic flux and the subsequent discovery of active metabolic pathways within a cell.

The protozoan parasites P. falciparum and T. brucei are the causative agents of malaria and human African trypanosomiasis, respectively. These parasites salvage many nutrients from the host, or from the medium in cell culture experiments, but also possess numerous active metabolic pathways.

U-13C-glucose labelling in cell cultures, combined with high-resolution mass specrotmetry-based metabolomics, allowed direct observation of the fate of glucose utilization in these protozoan pathogens. According to published models, T. brucei was thought to have a streamlined glucose metabolism, limited to glycolysis. However, our approach demonstrated incorporation of glucose-derived carbon into over 100 metabolites, revealing the presence of novel active metabolic pathways in these organisms.

Extensive post-glycolytic metabolism was also observed in P. falciparum, and stable isotope-labelled metabolomics analysis of knockout lines revealed a novel activity for the enzyme putatively annotated as branched chain keto-acid dehydrogenase (BCKDH) linking glycolysis to the TCA cycle.

Stable isotope labelling coupled with untargeted metabolomics enabled system-wide evaluation of active metabolic pathways in protozoan pathogens. Several novel pathways and enzyme activities were identified in T. brucei and P. falciparum, allowing significant extensions to previous models of glucose metabolism. This experimentally-derived, systems-based depiction of the active metabolic networks in these pathogens will assist in the elucidation of potential drug targets for the treatment of parasitic diseases.