Combining reverse genetics and nuclear magnetic resonance‐based metabolomics unravels trypanosome‐specific metabolic pathways

Abstract

SummaryNumerous eukaryotes have developed specific metabolic traits that are not present in extensively studied model organisms. For instance, the procyclic insect form of Trypanosoma brucei, a parasite responsible for sleeping sickness in its mammalianspecific bloodstream form, metabolizes glucose into excreted succinate and acetate through pathways with unique features. Succinate is primarily produced from glucose-derived phosphoenolpyruvate in peroxisome-like organelles, also known as glycosomes, by a soluble NADH-dependent fumarate reductase only described in trypanosomes so far. Acetate is produced in the mitochondrion of the parasite from acetyl-CoA by a CoA-transferase, which forms an ATP-producing cycle with succinylCoA synthetase. The role of this cycle in ATP production was recently demonstrated in procyclic trypanosomes and has only been proposed so far for anaerobic organisms, in addition to trypanosomatids. We review how nuclear magnetic resonance spectrometry can be used to analyze the metabolic network perturbed by deletion (knockout) or downregulation (RNAi) of the candidate genes involved in these two particular metabolic pathways of procyclic trypanosomes. The role of succinate and acetate production in trypanosomes is discussed, as well as the connections between the succinate and acetate branches, which increase the metabolic flexibility probably required by the parasite to deal with environmental changes such as oxidative stress.

Metabolic reprogramming during the Trypanosoma brucei life cycle

“…In a way, the life cycle of a pathogen is a series of irreversible differentiation steps, in which the cells adapt to a new environment to perform new functions. In addition, the use of modern metabolomics approaches has revealed that T. brucei uses an incomplete TCA cycle in PFs 53 and that proline has a different fate in PFs depending upon high- or low-glucose availability in the medium and has allowed the identification of the carbon and nitrogen sources of essential metabolites 53– 56 .…”

Comparative molecular cell biology of phototrophic euglenids and parasitic trypanosomatids sheds light on the ancestor of Euglenozoa

“…However, the trypanosomatid Krebs cycle does not function as a classical cycle. Pyruvate is converted mainly to acetate in a reaction linked with ATP synthesis (Tielens & van Hellemond, ; Bringaud et al, ). A similar reaction series has been described in a number of unicellular and multicellular species, but trypanosomatids are among the few species requiring oxygen (Müller et al, ).…”

Sleeping Sickness in the ‘Omics Era

“…Metabolomics studies using different strategies have been essential to better understand trypanosome metabolism within the different hosts, including the important role of glycolysis and of glycolysis end‐products . As reviewed by Bringaud et al., different metabolomics approaches, such as nuclear magnetic resonance (NMR)‐based metabolomics, associated with alteration of the expression of genes of interest via knockout or RNAi, can be particularly useful for the characterization and understanding of metabolic pathways specific to T. brucei BSF or PCF.…”