In:
PLOS Pathogens, Public Library of Science (PLoS), Vol. 17, No. 3 ( 2021-3-1), p. e1009204-
Abstract:
Trypanosoma brucei , a protist responsible for human African trypanosomiasis (sleeping sickness), is transmitted by the tsetse fly where the procyclic forms of the parasite develop in the proline-rich (1–2 mM) and glucose-depleted digestive tract. Proline is essential for the midgut colonization of the parasite in the insect vector, however other carbon sources could be available and used to feed its central metabolism. Here we show that procyclic trypanosomes can consume and metabolize metabolic intermediates, including those excreted from glucose catabolism (succinate, alanine and pyruvate), with the exception of acetate, which is the ultimate end-product excreted by the parasite. Among the tested metabolites, tricarboxylic acid (TCA) cycle intermediates (succinate, malate and α-ketoglutarate) stimulated growth of the parasite in the presence of 2 mM proline. The pathways used for their metabolism were mapped by proton-NMR metabolic profiling and phenotypic analyses of thirteen RNAi and/or null mutants affecting central carbon metabolism. We showed that ( i ) malate is converted to succinate by both the reducing and oxidative branches of the TCA cycle, which demonstrates that procyclic trypanosomes can use the full TCA cycle, ( ii ) the enormous rate of α-ketoglutarate consumption (15-times higher than glucose) is possible thanks to the balanced production and consumption of NADH at the substrate level and ( iii ) α-ketoglutarate is toxic for trypanosomes if not appropriately metabolized as observed for an α-ketoglutarate dehydrogenase null mutant. In addition, epimastigotes produced from procyclics upon overexpression of RBP6 showed a growth defect in the presence of 2 mM proline, which is rescued by α-ketoglutarate, suggesting that physiological amounts of proline are not sufficient per se for the development of trypanosomes in the fly. In conclusion, these data show that trypanosomes can metabolize multiple metabolites, in addition to proline, which allows them to confront challenging environments in the fly.
Type of Medium:
Online Resource
ISSN:
1553-7374
DOI:
10.1371/journal.ppat.1009204
DOI:
10.1371/journal.ppat.1009204.g001
DOI:
10.1371/journal.ppat.1009204.g002
DOI:
10.1371/journal.ppat.1009204.g003
DOI:
10.1371/journal.ppat.1009204.g004
DOI:
10.1371/journal.ppat.1009204.g005
DOI:
10.1371/journal.ppat.1009204.g006
DOI:
10.1371/journal.ppat.1009204.g007
DOI:
10.1371/journal.ppat.1009204.g008
DOI:
10.1371/journal.ppat.1009204.t001
DOI:
10.1371/journal.ppat.1009204.s001
DOI:
10.1371/journal.ppat.1009204.s002
DOI:
10.1371/journal.ppat.1009204.s003
DOI:
10.1371/journal.ppat.1009204.s004
DOI:
10.1371/journal.ppat.1009204.s005
Language:
English
Publisher:
Public Library of Science (PLoS)
Publication Date:
2021
detail.hit.zdb_id:
2205412-1