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1. Procyclic trypanosomes recycle glucose catabolites and TCA cycle intermediates to stimulate growth in the presence of physiological amounts of proline.

Author

Villafraz O, Biran M, Pineda E, Plazolles N, Cahoreau E, Ornitz Oliveira Souza R, Thonnus M, Allmann S, Tetaud E, Rivière L, Silber AM, Barrett MP, Zíková A, Boshart M, Portais JC, and Bringaud F

Subjects
Animals, Citric Acid Cycle drug effects, Insect Vectors parasitology, Oxidation-Reduction drug effects, Proline metabolism, RNA Interference physiology, Trypanosoma metabolism, Trypanosoma brucei brucei metabolism, Trypanosomiasis, African drug therapy, Tsetse Flies parasitology, Glucose metabolism, Proline pharmacology, Trypanosoma drug effects, Trypanosoma brucei brucei drug effects, Tsetse Flies drug effects
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., Competing Interests: The authors have declared that no competing interests exist.

Published
2021
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2. Streptococcus pyogenes Cas9 ribonucleoprotein delivery for efficient, rapid and marker‐free gene editing in Trypanosoma and Leishmania.

Author

Asencio, Corinne, Hervé, Perrine, Morand, Pauline, Oliveres, Quentin, Morel, Chloé Alexandra, Prouzet‐Mauleon, Valérie, Biran, Marc, Monic, Sarah, Bonhivers, Mélanie, Robinson, Derrick Roy, Ouellette, Marc, Rivière, Loïc, Bringaud, Frédéric, and Tetaud, Emmanuel

Subjects
TRYPANOSOMA, GENOME editing, AFRICAN trypanosomiasis, STREPTOCOCCUS pyogenes, ECONOMIC impact of disease, LIFE cycles (Biology), LEISHMANIA
Abstract

Kinetoplastids are unicellular eukaryotic flagellated parasites found in a wide range of hosts within the animal and plant kingdoms. They are known to be responsible in humans for African sleeping sickness (Trypanosoma brucei), Chagas disease (Trypanosoma cruzi), and various forms of leishmaniasis (Leishmania spp.), as well as several animal diseases with important economic impact (African trypanosomes, including Trypanosoma congolense). Understanding the biology of these parasites necessarily implies the ability to manipulate their genomes. In this study, we demonstrate that transfection of a ribonucleoprotein complex, composed of recombinant Streptococcus pyogenes Cas9 (SpCas9) and an in vitro‐synthesized guide RNA, results in rapid and efficient genetic modifications of trypanosomatids, in marker‐free conditions. This approach was successfully developed to inactivate, delete, and mutate candidate genes in various stages of the life cycle of T. brucei and T. congolense, and Leishmania promastigotes. The functionality of SpCas9 in these parasites now provides, to the research community working on these parasites, a rapid and efficient method of genome editing, without requiring plasmid construction and selection by antibiotics but requires only cloning and PCR screening of the clones. Importantly, this approach is adaptable to any wild‐type parasite. [ABSTRACT FROM AUTHOR]

Published
2024
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3. Procyclic trypanosomes recycle glucose catabolites and TCA cycle intermediates to stimulate growth in the presence of physiological amounts of proline

Author

Villafraz, Oriana, Biran, Marc, Pineda, Erika, Plazolles, Nicolas, Cahoreau, Edern, Ornitz Oliveira Souza, Rodolpho, Thonnus, Magali, Allmann, Stefan, Tetaud, Emmanuel, Rivière, Loïc, Silber, Ariel M., Barrett, Michael P., Zíková, Alena, Boshart, Michael, Portais, Jean-Charles, Bringaud, Frédéric, Microbiologie Fondamentale et Pathogénicité (MFP), Université Bordeaux Segalen - Bordeaux 2-Centre National de la Recherche Scientifique (CNRS), Centre de résonance magnétique des systèmes biologiques (CRMSB), Université de Bordeaux (UB)-Centre National de la Recherche Scientifique (CNRS), Toulouse Biotechnology Institute (TBI), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), MetaToul FluxoMet (TBI-MetaToul), MetaboHUB-MetaToul, MetaboHUB-Génopole Toulouse Midi-Pyrénées [Auzeville] (GENOTOUL), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Ecole Nationale Vétérinaire de Toulouse (ENVT), Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-MetaboHUB-Génopole Toulouse Midi-Pyrénées [Auzeville] (GENOTOUL), Université de Toulouse (UT)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Toulouse Biotechnology Institute (TBI), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Universidade de São Paulo = University of São Paulo (USP), Ludwig-Maximilians-Universität München (LMU), University of Glasgow, Institute of Parasitology [České Budějovice] (BIOLOGY CENTRE CAS), Biology Centre of the Czech Academy of Sciences (BIOLOGY CENTRE CAS), Czech Academy of Sciences [Prague] (CAS)-Czech Academy of Sciences [Prague] (CAS), Geroscience and rejuvenation research center (RESTORE), Université de Toulouse (UT)-Université de Toulouse (UT)-EFS-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Université de Bordeaux, CNRS, ANR-11-INBS-0010,METABOHUB,Développement d'une infrastructure française distribuée pour la métabolomique dédiée à l'innovation(2011), ANR-15-CE15-0025,GLYCONOV,Voies métaboliques glycosomales non glycolytiques: nouvelles fonctions pour le développement et la virulence des trypanosomes(2015), ANR-19-CE15-0004,AdipoTryp,Interactions métaboliques entre les adipocytes et les trypanosomes, un nouveau paradigme pour les trypanosomoses(2019), ANR-11-LABX-0024,ParaFrap,Alliance française contre les maladies parasitaires(2011), Université de Bordeaux (UB), Microbiologie cellulaire et moléculaire et pathogénicité (MCMP), Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Universidade de São Paulo (USP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-EFS-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), ANR-15-CE15-002501, ANR19-CE15-0004-01, Institut National des Sciences Appliquées (INSA)-Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées (INSA)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Génopole Toulouse Midi-Pyrénées [Auzeville] (GENOTOUL), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Ecole Nationale Vétérinaire de Toulouse (ENVT), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Génopole Toulouse Midi-Pyrénées [Auzeville] (GENOTOUL), Université Fédérale Toulouse Midi-Pyrénées-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Toulouse Biotechnology Institute (TBI), Institut National des Sciences Appliquées (INSA)-Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées (INSA)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), VIAUD, Karine, Développement d'une infrastructure française distribuée pour la métabolomique dédiée à l'innovation - - METABOHUB2011 - ANR-11-INBS-0010 - INBS - VALID, Voies métaboliques glycosomales non glycolytiques: nouvelles fonctions pour le développement et la virulence des trypanosomes - - GLYCONOV2015 - ANR-15-CE15-0025 - AAPG2015 - VALID, Interactions métaboliques entre les adipocytes et les trypanosomes, un nouveau paradigme pour les trypanosomoses - - AdipoTryp2019 - ANR-19-CE15-0004 - AAPG2019 - VALID, and Laboratoires d'excellence - Alliance française contre les maladies parasitaires - - ParaFrap2011 - ANR-11-LABX-0024 - LABX - VALID

Subjects
Metabolic Processes, Pyruvate, Trypanosoma, Proline, Tsetse Flies, QH301-705.5, Physiology, Citric Acid Cycle, Trypanosoma brucei brucei, Excretion, Carbohydrates, [SDV.MP.PRO] Life Sciences [q-bio]/Microbiology and Parasitology/Protistology, Biochemistry, [SDV.MP.PRO]Life Sciences [q-bio]/Microbiology and Parasitology/Protistology, Glucose Metabolism, Animals, [SDV.MP.PAR]Life Sciences [q-bio]/Microbiology and Parasitology/Parasitology, Biology (General), Amino Acids, Protozoans, Alanine, Organic Compounds, Organic Chemistry, Monosaccharides, fungi, Organisms, Chemical Compounds, Biology and Life Sciences, Eukaryota, Proteins, Cyclic Amino Acids, RC581-607, Ketones, Parasitic Protozoans, Insect Vectors, Chemistry, Glucose, Trypanosomiasis, African, Metabolism, Aliphatic Amino Acids, Physical Sciences, Carbohydrate Metabolism, RNA Interference, Immunologic diseases. Allergy, Physiological Processes, Oxidation-Reduction, Acids, [SDV.MP.PAR] Life Sciences [q-bio]/Microbiology and Parasitology/Parasitology, Research Article
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., Author summary In the midgut of its insect vector, trypanosomes rely on proline to feed their energy metabolism. However, the availability of other potential carbon sources that can be used by the parasite is currently unknown. Here we show that tricarboxylic acid (TCA) cycle intermediates, i.e. succinate, malate and α-ketoglutarate, stimulate growth of procyclic trypanosomes incubated in a medium containing 2 mM proline, which is in the range of the amounts measured in the midgut of the fly. Some of these additional carbon sources are needed for the development of epimastigotes, which differentiate from procyclics in the midgut of the fly, since their growth defect observed in the presence of 2 mM proline is rescued by addition of α-ketoglutarate. In addition, we have implemented new approaches to study a poorly explored branch of the TCA cycle converting malate to α-ketoglutarate, which was previously described as non-functional in the parasite, regardless of the glucose levels available. The discovery of this branch reveals that a full TCA cycle can operate in procyclic trypanosomes. Our data broaden the metabolic potential of trypanosomes and pave the way for a better understanding of the parasite’s metabolism in various organ systems of the tsetse fly, where it develops.

Published
2021
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4. Metabolic selection of a homologous recombination-mediated gene loss protects Trypanosoma brucei from ROS production by glycosomal fumarate reductase

Author

Wargnies, Marion, Plazolles, Nicolas, Schenk, Robin, Villafraz, Oriana, Dupuy, Jean-William, Biran, Marc, Bachmaier, Sabine, Baudouin, Hélène, Clayton, Christine, Boshart, Michael, Bringaud, Frédéric, Université de Bordeaux (UB), Centre de résonance magnétique des systèmes biologiques (CRMSB), Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB), Microbiologie cellulaire et moléculaire et pathogénicité (MCMP), Université Bordeaux Segalen - Bordeaux 2-Centre National de la Recherche Scientifique (CNRS), Ludwig-Maximilians-Universität München (LMU), Plateforme Protéome [Bordeaux], Centre Génomique Fonctionnelle Bordeaux [Bordeaux] (CGFB), Institut Polytechnique de Bordeaux-Université de Bordeaux Ségalen [Bordeaux 2]-Institut Polytechnique de Bordeaux-Université de Bordeaux Ségalen [Bordeaux 2], and Universität Heidelberg [Heidelberg]

Subjects
phosphoenolpyruvate carboxykinase (PEPCK), Trypanosoma brucei brucei, homologous recombination, Microbodies, ROS, reactive oxygen species, PPDK, pyruvate phosphate dikinase, positive selection, Flavins, [SDV.BBM.GTP]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Genomics [q-bio.GN], [SDV.MP.PAR]Life Sciences [q-bio]/Microbiology and Parasitology/Parasitology, Cells, Cultured, ComputingMilieux_MISCELLANEOUS, trypanosoma, Cytb5R domain, reactive oxygen species, parasite differentiation, PEP, phosphoenolpyruvate, PCF, procyclic form, ACN, acetonitrile, covalent flavinylation, FRD, fumarate reductase, Succinate Dehydrogenase, Glucose, genomic rearrangement, PEPCK, phosphoenolpyruvate carboxykinase, NADH-dependent fumarate reductase (FRD), Research Article
Abstract

International audience; The genome of trypanosomatids rearranges by using repeated sequences as platforms for amplification or deletion of genomic segments. These stochastic recombination events have a direct impact on gene dosage and foster the selection of adaptive traits in response to environmental pressure. We provide here such an example by showing that the phosphoenolpyruvate carboxykinase (PEPCK) gene knockout (Δpepck) leads to the selection of a deletion event between two tandemly arranged fumarate reductase (FRDg and FRDm2) genes to produce a chimeric FRDg-m2 gene in the Δpepck∗ cell line. FRDg is expressed in peroxisome-related organelles, named glycosomes, expression of FRDm2 has not been detected to date, and FRDg-m2 is nonfunctional and cytosolic. Re-expression of FRDg significantly impaired growth of the Δpepck∗ cells, but FRD enzyme activity was not required for this negative effect. Instead, glycosomal localization as well as the covalent flavinylation motif of FRD is required to confer growth retardation and intracellular accumulation of reactive oxygen species (ROS). The data suggest that FRDg, similar to Escherichia coli FRD, can generate ROS in a flavin-dependent process by transfer of electrons from NADH to molecular oxygen instead of fumarate when the latter is unavailable, as in the Δpepck background. Hence, growth retardation is interpreted as a consequence of increased production of ROS, and rearrangement of the FRD locus liberates Δpepck∗ cells from this obstacle. Interestingly, intracellular production of ROS has been shown to be required to complete the parasitic cycle in the insect vector, suggesting that FRDg may play a role in this process

Published
2021
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5. Gluconeogenesis is essential for trypanosome development in the tsetse fly vector

Author

Wargnies, Marion, Bertiaux, Eloise, Cahoreau, Edern, Ziebart, Nicole, Crouzols, Aline, Morand, Pauline, Biran, Marc, Allmann, Stefan, Hubert, Jane, Villafraz, Oriana, Millerioux, Yoann, Plazolles, Nicolas, Asencio, Corinne, Rivière, Loïc, Rotureau, Brice, Boshart, Michael, Portais, Jean-Charles, Bringaud, Frédéric, Microbiologie Fondamentale et Pathogénicité (MFP), Université Bordeaux Segalen - Bordeaux 2-Centre National de la Recherche Scientifique (CNRS), Centre de résonance magnétique des systèmes biologiques (CRMSB), Université de Bordeaux (UB)-Centre National de la Recherche Scientifique (CNRS), Biologie cellulaire des Trypanosomes - Trypanosome Cell Biology, Institut Pasteur [Paris] (IP)-Institut National de la Santé et de la Recherche Médicale (INSERM), Laboratoire d'Ingénierie des Systèmes Biologiques et des Procédés (LISBP), Institut National de la Recherche Agronomique (INRA)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS), MetaToul FluxoMet (TBI-MetaToul), MetaboHUB-MetaToul, MetaboHUB-Génopole Toulouse Midi-Pyrénées [Auzeville] (GENOTOUL), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Ecole Nationale Vétérinaire de Toulouse (ENVT), Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-MetaboHUB-Génopole Toulouse Midi-Pyrénées [Auzeville] (GENOTOUL), Université de Toulouse (UT)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Toulouse Biotechnology Institute (TBI), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Ludwig-Maximilians-Universität München (LMU), The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. FB's and BR's group were funded by the Agence Nationale de la Recherche (ANR) through GLYCONOV (grant number ANR-15-CE15-0025-01) of the ANR-BLANC-2015 call. FB's group was supported by the Centre National de la Recherche Scientifique (CNRS), the Université de Bordeaux, the ANR through the grants ACETOTRYP (grant number ANR-2010-BLAN-1319-02) of the ANR-BLANC-2010 call, the Laboratoire d’Excellence (LabEx) ParaFrap ANR-11-LABX-0024 and the ParaMet PhD programme of Marie Curie Initial Training Network. BR’s group was supported by the Institut Pasteur, the Institut National de la Santé et de la Recherche Médicale (INSERM). EB is funded by a doctoral fellowship from French National Ministry for Research and Technology (Doctoral School CDV515). MB was funded by the University of Munich and MB and FB were supported by a research cooperation grant of the Franco-Bavarian University Cooperation Center (BFHZ/CCUFB)., ANR-15-CE15-0025,GLYCONOV,Voies métaboliques glycosomales non glycolytiques: nouvelles fonctions pour le développement et la virulence des trypanosomes(2015), ANR-10-BLAN-1319,ACETOTRYP,Metabolisme de l'acetyl-CoA et de l'acetate chez les trypanosomes: identification de nouvelles voies métaboliques spécifiques aux parasites(2010), ANR-11-LABX-0024,ParaFrap,Alliance française contre les maladies parasitaires(2011), Microbiologie cellulaire et moléculaire et pathogénicité (MCMP), Résonance magnétique des systèmes biologiques (RMSB), Biologie cellulaire des Trypanosomes, Institut Pasteur [Paris]-Institut National de la Santé et de la Recherche Médicale (INSERM), Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Institut National de la Recherche Agronomique (INRA), Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB), Institut National des Sciences Appliquées (INSA)-Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées (INSA)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Génopole Toulouse Midi-Pyrénées [Auzeville] (GENOTOUL), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Ecole Nationale Vétérinaire de Toulouse (ENVT), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Génopole Toulouse Midi-Pyrénées [Auzeville] (GENOTOUL), Université Fédérale Toulouse Midi-Pyrénées-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Toulouse Biotechnology Institute (TBI), Institut National des Sciences Appliquées (INSA)-Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées (INSA)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Rotureau, Brice, Voies métaboliques glycosomales non glycolytiques: nouvelles fonctions pour le développement et la virulence des trypanosomes - - GLYCONOV2015 - ANR-15-CE15-0025 - AAPG2015 - VALID, BLANC - Metabolisme de l'acetyl-CoA et de l'acetate chez les trypanosomes: identification de nouvelles voies métaboliques spécifiques aux parasites - - ACETOTRYP2010 - ANR-10-BLAN-1319 - BLANC - VALID, and Laboratoires d'excellence - Alliance française contre les maladies parasitaires - - ParaFrap2011 - ANR-11-LABX-0024 - LABX - VALID

Subjects
Glycerol, gène codant, Disease Vectors, Biochemistry, Salivary Glands, Glucose Metabolism, Medicine and Health Sciences, Biology (General), Amino Acids, Protozoans, surexpression, Organic Compounds, Microbiology and Parasitology, Monosaccharides, Monomers, Eukaryota, Microbiologie et Parasitologie, Chemistry, [SDV.MP]Life Sciences [q-bio]/Microbiology and Parasitology, protéine, Physical Sciences, Carbohydrate Metabolism, Anatomy, [SDV.MP.PAR] Life Sciences [q-bio]/Microbiology and Parasitology/Parasitology, Research Article, Trypanosoma, Tsetse Flies, Proline, QH301-705.5, Trypanosoma brucei brucei, Carbohydrates, [SDV.MP.PRO]Life Sciences [q-bio]/Microbiology and Parasitology/Protistology, Phosphates, Exocrine Glands, Parasitic Diseases, Animals, [SDV.MP.PAR]Life Sciences [q-bio]/Microbiology and Parasitology/Parasitology, [SDV.MP] Life Sciences [q-bio]/Microbiology and Parasitology, gluconeogénèse, Organic Chemistry, Gluconeogenesis, Organisms, Chemical Compounds, Biology and Life Sciences, Proteins, Cyclic Amino Acids, RC581-607, mouche tsé tsé, Polymer Chemistry, Parasitic Protozoans, enzyme, Trypanosomiasis, African, Metabolism, Glucose, Immunologic diseases. Allergy, Digestive System, trypanosoma brucei
Abstract

In the glucose-free environment that is the midgut of the tsetse fly vector, the procyclic form of Trypanosoma brucei primarily uses proline to feed its central carbon and energy metabolism. In these conditions, the parasite needs to produce glucose 6-phosphate (G6P) through gluconeogenesis from metabolism of non-glycolytic carbon source(s). We showed here that two phosphoenolpyruvate-producing enzymes, PEP carboxykinase (PEPCK) and pyruvate phosphate dikinase (PPDK) have a redundant function for the essential gluconeogenesis from proline. Indeed, incorporation of 13C-enriched proline into G6P was abolished in the PEPCK/PPDK null double mutant (Δppdk/Δpepck), but not in the single Δppdk and Δpepck mutant cell lines. The procyclic trypanosome also uses the glycerol conversion pathway to feed gluconeogenesis, since the death of the Δppdk/Δpepck double null mutant in glucose-free conditions is only observed after RNAi-mediated down-regulation of the expression of the glycerol kinase, the first enzyme of the glycerol conversion pathways. Deletion of the gene encoding fructose-1,6-bisphosphatase (Δfbpase), a key gluconeogenic enzyme irreversibly producing fructose 6-phosphate from fructose 1,6-bisphosphate, considerably reduced, but not abolished, incorporation of 13C-enriched proline into G6P. In addition, the Δfbpase cell line is viable in glucose-free conditions, suggesting that an alternative pathway can be used for G6P production in vitro. However, FBPase is essential in vivo, as shown by the incapacity of the Δfbpase null mutant to colonise the fly vector salivary glands, while the parental phenotype is restored in the Δfbpase rescued cell line re-expressing FBPase. The essential role of FBPase for the development of T. brucei in the tsetse was confirmed by taking advantage of an in vitro differentiation assay based on the RNA-binding protein 6 over-expression, in which the procyclic forms differentiate into epimastigote forms but not into mammalian-infective metacyclic parasites. In total, morphology, immunofluorescence and cytometry analyses showed that the differentiation of the epimastigote stages into the metacyclic forms is abolished in the Δfbpase mutant., Author summary Trypanosoma brucei, the parasite responsible for sleeping sickness in humans, is transmitted by the tsetse fly that primarily uses amino acids for its energy production. In the glucose-free environment encountered between the insect blood meals, T. brucei needs to produce through gluconeogenesis glucose 6-phosphate, a key precursor for several essential metabolic pathways. We have shown here that two key gluconeogenic steps, which produce phosphoenolpyruvate and fructose 6-phosphate, respectively, are performed by redundant enzymes (PPDK and PEPCK for phosphoenolpyruvate production; FBPase and a yet unknown enzyme for fructose 6-phosphate production), which highlights the importance of this metabolic pathway for the insect stages of the parasite. Interestingly, deletion of the parasite FBPase gene abolished both the colonisation of the insect salivary glands and the in vitro differentiation of the epimastigote forms into the mammalian infective form of the parasite. Altogether, these data demonstrate for the first time that gluconeogenesis is essential for development of T. brucei in its insect vector and that early development stages of the parasite present in the tsetse midgut are not affected by the absence of FBPase, probably by developing an alternative yet unknown approach to produce fructose 6-phosphate.

Published
2018
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6. De novo biosynthesis of sterols and fatty acids in the Trypanosoma brucei procyclic form: Carbon source preferences and metabolic flux redistributions

Author

Millerioux, Yoann, Mazet, Muriel, Bouyssou, Guillaume, Allmann, Stefan, Kiema, Tiila-Riikka, Bertiaux, Eloise, Fouillen, Laetitia, Thapa, Chandan, Biran, Marc, Plazolles, Nicolas, Dittrich-Domergue, Franziska, Crouzols, Aline, Wierenga, Rik, Rotureau, Brice, MOREAU, Patrick, Bringaud, Frédéric, Microbiologie Fondamentale et Pathogénicité (MFP), Université Bordeaux Segalen - Bordeaux 2-Centre National de la Recherche Scientifique (CNRS), Centre de résonance magnétique des systèmes biologiques (CRMSB), Université de Bordeaux (UB)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de biogenèse membranaire (LBM), University of Oulu, Biologie cellulaire des Trypanosomes - Trypanosome Cell Biology, Institut Pasteur [Paris] (IP)-Institut National de la Santé et de la Recherche Médicale (INSERM), This research was supported by the Centre National de la Recherche Scientifique (CNRS), the Université de Bordeaux, the Agence Nationale de la Recherche (ANR) through grants ACETOTRYP (grant number ANR-2010-BLAN-1319-02) of the ANR-BLANC-2010 call and GLYCONOV (grant number ANR-15-CE15-0025-01) of the 'Générique' 2015 call, the Laboratoire d’Excellence (LabEx) ParaFrap (grant number ANR-11-LABX-0024), the Institut Pasteur and by the European Commission FP7 Marie Curie Initial Training Network 'ParaMet' (grant number 290080). EB was funded by a doctoral fellowship from French National Ministry for Research and Technology (doctoral school CDV515)., ANR-10-BLAN-1319,ACETOTRYP,Metabolisme de l'acetyl-CoA et de l'acetate chez les trypanosomes: identification de nouvelles voies métaboliques spécifiques aux parasites(2010), ANR-11-LABX-0024,ParaFrap,Alliance française contre les maladies parasitaires(2011), European Project: 290080,EC:FP7:PEOPLE,FP7-PEOPLE-2011-ITN,PARAMET(2012), Résonance magnétique des systèmes biologiques (RMSB), Laboratoire Microorganismes : Génome et Environnement (LMGE), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Université d'Auvergne - Clermont-Ferrand I (UdA)-Centre National de la Recherche Scientifique (CNRS), Microbiologie cellulaire et moléculaire et pathogénicité (MCMP), Biologie cellulaire des Trypanosomes, Institut Pasteur [Paris]-Institut National de la Santé et de la Recherche Médicale (INSERM), Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB), Rotureau, Brice, BLANC - Metabolisme de l'acetyl-CoA et de l'acetate chez les trypanosomes: identification de nouvelles voies métaboliques spécifiques aux parasites - - ACETOTRYP2010 - ANR-10-BLAN-1319 - BLANC - VALID, Laboratoires d'excellence - Alliance française contre les maladies parasitaires - - ParaFrap2011 - ANR-11-LABX-0024 - LABX - VALID, and A systematic analysis of parasite metabolism - from metabolism to intervention - PARAMET - - EC:FP7:PEOPLE2012-06-01 - 2016-05-31 - 290080 - VALID

Subjects
Threonine, [SDV]Life Sciences [q-bio], blood-sream forms, Acetates, Biochemistry, molecular characterization, Gene Knockout Techniques, dependent enzyme, Glucose Metabolism, proline metabolism, MESH: Animals, Amino Acids, MESH: Threonine, lcsh:QH301-705.5, MESH: Gene Knockout Techniques, Protozoans, MESH: Tsetse Flies, Organic Compounds, Fatty Acids, Monosaccharides, Eukaryota, cell-cycle, acetyl-coa, energy-metabolism, lipbiosyntesis, leishmania-mexicana, succinate coa-transferase, MESH: Mevalonic Acid, Lipids, MESH: Gene Expression Regulation, [SDV.BBM.BC]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Biomolecules [q-bio.BM], MESH: Fatty Acids, [SDV] Life Sciences [q-bio], MESH: Glucose, Sterols, Chemistry, [SDV.MP]Life Sciences [q-bio]/Microbiology and Parasitology, Physical Sciences, Carbohydrate Metabolism, MESH: Acetates, [SDV.MP.PAR] Life Sciences [q-bio]/Microbiology and Parasitology/Parasitology, Research Article, lcsh:Immunologic diseases. Allergy, Trypanosoma, Proline, Tsetse Flies, Trypanosoma brucei brucei, Carbohydrates, Mevalonic Acid, MESH: Carbon, MESH: Insect Vectors, Biosynthesis, [SDV.MP.PRO]Life Sciences [q-bio]/Microbiology and Parasitology/Protistology, MESH: Alcohol Oxidoreductases, Acetyl Coenzyme A, Acetyltransferases, Leucine, Hydroxyl Amino Acids, MESH: Acyl Coenzyme A, Animals, [SDV.MP.PAR]Life Sciences [q-bio]/Microbiology and Parasitology/Parasitology, [SDV.MP] Life Sciences [q-bio]/Microbiology and Parasitology, MESH: Proline, Organic Chemistry, Organisms, Chemical Compounds, Biology and Life Sciences, Proteins, MESH: Trypanosoma brucei brucei, MESH: Acetyltransferases, Carbon, Parasitic Protozoans, Insect Vectors, Alcohol Oxidoreductases, Glucose, Metabolism, MESH: Leucine, Gene Expression Regulation, Aliphatic Amino Acids, lcsh:Biology (General), MESH: Sterols, Acyl Coenzyme A, lcsh:RC581-607, MESH: Acetyl Coenzyme A
Abstract

De novo biosynthesis of lipids is essential for Trypanosoma brucei, a protist responsible for the sleeping sickness. Here, we demonstrate that the ketogenic carbon sources, threonine, acetate and glucose, are precursors for both fatty acid and sterol synthesis, while leucine only contributes to sterol production in the tsetse fly midgut stage of the parasite. Degradation of these carbon sources into lipids was investigated using a combination of reverse genetics and analysis of radio-labelled precursors incorporation into lipids. For instance, (i) deletion of the gene encoding isovaleryl-CoA dehydrogenase, involved in the leucine degradation pathway, abolished leucine incorporation into sterols, and (ii) RNAi-mediated down-regulation of the SCP2-thiolase gene expression abolished incorporation of the three ketogenic carbon sources into sterols. The SCP2-thiolase is part of a unidirectional two-step bridge between the fatty acid precursor, acetyl-CoA, and the precursor of the mevalonate pathway leading to sterol biosynthesis, 3-hydroxy-3-methylglutaryl-CoA. Metabolic flux through this bridge is increased either in the isovaleryl-CoA dehydrogenase null mutant or when the degradation of the ketogenic carbon sources is affected. We also observed a preference for fatty acids synthesis from ketogenic carbon sources, since blocking acetyl-CoA production from both glucose and threonine abolished acetate incorporation into sterols, while incorporation of acetate into fatty acids was increased. Interestingly, the growth of the isovaleryl-CoA dehydrogenase null mutant, but not that of the parental cells, is interrupted in the absence of ketogenic carbon sources, including lipids, which demonstrates the essential role of the mevalonate pathway. We concluded that procyclic trypanosomes have a strong preference for fatty acid versus sterol biosynthesis from ketogenic carbon sources, and as a consequence, that leucine is likely to be the main source, if not the only one, used by trypanosomes in the infected insect vector digestive tract to feed the mevalonate pathway., Author summary In this study, we have (i) determined the carbon sources used by the Trypanosoma brucei procyclic insect form to feed the essential lipid biosynthetic pathways, (ii) further characterized the metabolic pathways leading to their degradation into acetyl-CoA (fatty acid precursor) and 3-hydroxy-3-methylglutaryl-CoA (sterol precursor) and (iii) showed that reduction of the ketogenic carbon sources degradation, favors their incorporation into fatty acids, instead of sterols. This fatty acid preference is compensated by an increase of leucine incorporation into sterols, which highlights the parasite adaptation capacity regarding carbon source availability by modulating the metabolic flux between branches within the network. This metabolic flexibility is particularly relevant for the insect stages of trypanosomes that evolve in the midgut and the salivary glands of their blood-feeding insect vector. One may also consider that, the metabolic flow redistribution towards the mevalonate pathway (sterol production) described in vitro also occurs in vivo, depending on the carbon source composition of the tsetse fly micro-environment, which may considerably vary along the digestive tract and depending on the fly feeding status, as well as in the other infected fly organs.

Published
2018
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7. Glycerol supports growth of the Trypanosoma brucei bloodstream forms in the absence of glucose: Analysis of metabolic adaptations on glycerol-rich conditions.

Author

Pineda, Erika, Thonnus, Magali, Mazet, Muriel, Mourier, Arnaud, Cahoreau, Edern, Kulyk, Hanna, Dupuy, Jean-William, Biran, Marc, Masante, Cyril, Allmann, Stefan, Rivière, Loïc, Rotureau, Brice, Portais, Jean-Charles, and Bringaud, Frédéric

Subjects
TRYPANOSOMA brucei, GLYCERIN, GLUCONEOGENESIS, WESTERN immunoblotting, FAT cells, MONOSACCHARIDES
Abstract

The bloodstream forms of Trypanosoma brucei (BSF), the parasite protist causing sleeping sickness, primarily proliferate in the blood of their mammalian hosts. The skin and adipose tissues were recently identified as additional major sites for parasite development. Glucose was the only carbon source known to be used by bloodstream trypanosomes to feed their central carbon metabolism, however, the metabolic behaviour of extravascular tissue-adapted parasites has not been addressed yet. Since the production of glycerol is an important primary function of adipocytes, we have adapted BSF trypanosomes to a glucose-depleted but glycerol-rich culture medium (CMM_Glyc/GlcNAc) and compared their metabolism and proteome to those of parasites grown in standard glucose-rich conditions (CMM_Glc). BSF were shown to consume 2-folds more oxygen per consumed carbon unit in CMM_Glyc/GlcNAc and were 11.5-times more sensitive to SHAM, a specific inhibitor of the plant-like alternative oxidase (TAO), which is the only mitochondrial terminal oxidase expressed in BSF. This is consistent with (i) the absolute requirement of the mitochondrial respiratory activity to convert glycerol into dihydroxyacetone phosphate, as deduced from the updated metabolic scheme and (ii) with the 1.8-fold increase of the TAO expression level compared to the presence of glucose. Proton NMR analysis of excreted end products from glycerol and glucose metabolism showed that these two carbon sources are metabolised through the same pathways, although the contributions of the acetate and succinate branches are more important in the presence of glycerol than glucose (10.2% versus 3.4% of the excreted end products, respectively). In addition, metabolomic analyses by mass spectrometry showed that, in the absence of glucose, 13C-labelled glycerol was incorporated into hexose phosphates through gluconeogenesis. As expected, RNAi-mediated down-regulation of glycerol kinase expression abolished glycerol metabolism and was lethal for BSF grown in CMM_Glyc/GlcNAc. Interestingly, BSF have adapted their metabolism to grow in CMM_Glyc/GlcNAc by concomitantly increasing their rate of glycerol consumption and decreasing that of glucose. However, the glycerol kinase activity was 7.8-fold lower in CMM_Glyc/GlcNAc, as confirmed by both western blotting and proteomic analyses. This suggests that the huge excess in glycerol kinase that is not absolutely required for glycerol metabolism, might be used for another yet undetermined non-essential function in glucose rich-conditions. Altogether, these data demonstrate that BSF trypanosomes are well-adapted to glycerol-rich conditions that could be encountered by the parasite in extravascular niches, such as the skin and adipose tissues. [ABSTRACT FROM AUTHOR]

Published
2018
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8. Combining reverse genetics and nuclear magnetic resonance-based metabolomics unravels trypanosome-specific metabolic pathways.

Author

Bringaud, Frédéric, Biran, Marc, Millerioux, Yoann, Wargnies, Marion, Allmann, Stefan, and Mazet, Muriel

Subjects
*REVERSE genetics, *NUCLEAR magnetic resonance, *METABOLOMICS, *TRYPANOSOMA, *AFRICAN trypanosomiasis, *OXIDATIVE stress, *PHYSIOLOGY
Abstract

Numerous eukaryotes have developed specific metabolic traits that are not present in extensively studied model organisms. For instance, the procyclic insect form of T rypanosoma brucei, a parasite responsible for sleeping sickness in its mammalian-specific 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 succinyl- CoA 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. [ABSTRACT FROM AUTHOR]

Published
2015
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9. Revisiting the Central Metabolism of the Bloodstream Forms of Trypanosoma brucei: Production of Acetate in the Mitochondrion Is Essential for Parasite Viability.

Author

Mazet, Muriel, Morand, Pauline, Biran, Marc, Bouyssou, Guillaume, Courtois, Pierrette, Daulouède, Sylvie, Millerioux, Yoann, Franconi, Jean-Michel, Vincendeau, Philippe, Moreau, Patrick, and Bringaud, Frédéric

Subjects
TRYPANOSOMA, TRYPANOSOMA brucei, ESSENTIAL fatty acids, MITOCHONDRIA, ACETATES, FATTY acids
Abstract

Background: The bloodstream forms of Trypanosoma brucei, the causative agent of sleeping sickness, rely solely on glycolysis for ATP production. It is generally accepted that pyruvate is the major end-product excreted from glucose metabolism by the proliferative long-slender bloodstream forms of the parasite, with virtually no production of succinate and acetate, the main end-products excreted from glycolysis by all the other trypanosomatid adaptative forms, including the procyclic insect form of T. brucei. Methodology/Principal Findings: A comparative NMR analysis showed that the bloodstream long-slender and procyclic trypanosomes excreted equivalent amounts of acetate and succinate from glucose metabolism. Key enzymes of acetate production from glucose-derived pyruvate and threonine are expressed in the mitochondrion of the long-slender forms, which produces 1.4-times more acetate from glucose than from threonine in the presence of an equal amount of both carbon sources. By using a combination of reverse genetics and NMR analyses, we showed that mitochondrial production of acetate is essential for the long-slender forms, since blocking of acetate biosynthesis from both carbon sources induces cell death. This was confirmed in the absence of threonine by the lethal phenotype of RNAi-mediated depletion of the pyruvate dehydrogenase, which is involved in glucose-derived acetate production. In addition, we showed that de novo fatty acid biosynthesis from acetate is essential for this parasite, as demonstrated by a lethal phenotype and metabolic analyses of RNAi-mediated depletion of acetyl-CoA synthetase, catalyzing the first cytosolic step of this pathway. Conclusions/Significance: Acetate produced in the mitochondrion from glucose and threonine is synthetically essential for the long-slender mammalian forms of T. brucei to feed the essential fatty acid biosynthesis through the "acetate shuttle" that was recently described in the procyclic insect form of the parasite. Consequently, key enzymatic steps of this pathway, particularly acetyl-CoA synthetase, constitute new attractive drug targets against trypanosomiasis. Author Summary: Many protists, including parasitic helminthes, trichomonads and trypanosomatids, produce acetate in their mitochondrion or mitochondrion-like organelle, which is excreted as a main metabolic end-product of their energy metabolism. We have recently demonstrated that mitochondrial production of acetate is essential for fatty acid biosynthesis and ATP production in the procyclic insect form of T. brucei. However, acetate metabolism has not been investigated in the long-slender bloodstream forms of the parasite, the proliferative forms responsible for the sleeping sickness. In contrast to the current view, we showed that the bloodstream forms produce almost as much acetate from glucose than the procyclic parasites. Acetate production from glucose and threonine is synthetically essential for growth and de novo synthesis of fatty acids of the bloodstream trypanosomes. These data highlight that the central metabolism of the bloodstream forms contains unexpected essential pathways, although minor in terms of metabolic flux, which could be targeted for the development of trypanocidal drugs. [ABSTRACT FROM AUTHOR]

Published
2013
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10. Alanine aminotransferase of Trypanosoma brucei– a key role in proline metabolism in procyclic life forms.

Author

Spitznagel, Diana, Ebikeme, Charles, Biran, Marc, Nic á Bháird, Nóirín, Bringaud, Frédéric, Henehan, Gary T. M., and Nolan, Derek P.

Subjects
ALANINE, TRYPANOSOMA, METABOLISM, NUCLEIC acids, PYRUVATES
Abstract

African trypanosomes possess high levels of alanine aminotransferase (EC 2.6.1.2), although the function of their activity remains enigmatic, especially in slender bloodstream forms where the metabolism of ketoacids does not occur. Therefore, the gene for alanine aminotransferase enzyme in Trypanosoma brucei ( TbAAT) was characterized and its function assessed using a combination of RNA interference and gene knockout approaches. Surprisingly, as much as 95% or more of the activity appears to be unnecessary for growth of either bloodstream or procyclic forms respiring on glucose. A combination of RNA interference and NMR spectroscopy revealed an important role for the activity in procyclic forms respiring on proline. Under these conditions, the major end product of proline metabolism is alanine, and a reduction in TbAAT activity led to a proportionate decrease in the amount of alanine excreted along with an increase in the doubling time of the cells. These results provide evidence of a role for alanine aminotransferase in the metabolism of proline in African trypanosomes by linking glutamate produced by the initial oxidative steps of the pathway with pyruvate produced by the final oxidative step of the pathway. This step appears to be essential when proline is the primary carbon source, which is likely to be the physiological situation in the tsetse fly vector. [ABSTRACT FROM AUTHOR]

Published
2009
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11. Acetate produced in the mitochondrion is the essential precursor for lipid biosynthesis in procyclic trypanosomes.

Author

Rivière, Loïc, Moreau, Patrick, Allmann, Stefan, Hahn, Matthias, Biran, Marc, Plazolles, Nicolas, Franconi, Jean-Michel, Boshart, Michael, and Bringaud, Frédéric

Subjects
BIOCHEMISTRY, LIPIDS, TRYPANOSOMA, BIOSYNTHESIS, ACETATES, MITOCHONDRIA
Abstract

Acetyl-CoA produced in mitochondria from carbohydrate or amino acid catabolism needs to reach the cytosol to initiate de novo synthesis of fatty acids. All eukaryotes analyzed so far use a citrate/malate shuttle to transfer acetyl group equivalents from the mitochondrial matrix to the cytosol. Here we investigate how this acetyl group transfer occurs in the procyclic life cycle stage of Trypanosoma brucei, a protozoan parasite responsible of human sleeping sickness and economically important livestock diseases. Deletion of the potential citrate lyase gene, a critical cytosolic enzyme of the citrate/malate shuttle, has no effect on de novo biosynthesis of fatty acids from 14C-labeled glucose, indicating that another route is used for acetyl group transfer. Because acetate is produced from acetyl-CoA in the mitochondrion of this parasite, we considered genes encoding cytosolic enzymes producing acetyl-CoA from acetate. We identified an acetyl-CoA synthetase gene encoding a cytosolic enzyme (AceCS), which is essential for cell viability. Repression of AceCS by inducible RNAi results in a 20-fold reduction of 14C-incorporation from radiolabeled glucose or acetate into de novo synthesized fatty acids. Thus, we demonstrate that the essential cytosolic enzyme AceCS of T. brucei is responsible for activation of acetate into acetyl-CoA to feed de novo biosynthesis of lipids. To date, Trypanosoma is the only known eukaryotic organism that uses acetate instead of citrate to transfer acetyl groups over the mitochondrial membrane for cytosolic lipid synthesis. [ABSTRACT FROM AUTHOR]

Published
2009
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12. Fumarate Is an Essential Intermediary Metabolite Produced by the Procyclic Trypanosoma brucei.

Author

Coustou, Virginie, Biran, Marc, Besteiro, Sébastien, Rivière, Loïc, Baltz, Théo, Franconi, Jean-Michel, and Bringaud, Frédéric

Subjects
*SUCCINATE dehydrogenase, *METABOLITES, *TRYPANOSOMA brucei, *ENZYMES, *TRYPANOSOMA
Abstract

The procyclic stage of Trypanosoma brucei, a parasitic protist responsible for sleeping sickness in humans, converts most of the consumed glucose into excreted succinate, by succinic fermentation. Succinate is produced by the glycosomal and mitochondrial NADH-dependent fumarate reductases, which are not essential for parasite viability. To further explore the role of the succinic fermentation pathways, we studied the trypanosome fumarases, the enzymes providing fumarate to fumarate reductases. The T. brucei genome contains two class I fumarase genes encoding cytosolic (FHc) and mitochondrial (FHm) enzymes, which account for total cellular fumarase activity as shown by RNA interference. The growth arrest of a double RNA interference mutant cell line showing no fumarase activity indicates that fumarases are essential for the parasite. Interestingly, addition of fumarate to the medium rescues the growth phenotype, indicating that fumarate is an essential intermediary metabolite of the insect stage trypanosomes. We propose that trypanosomes use fumarate as an essential electron acceptor, as exemplified by the fumarate dependence previously reported for an enzyme of the essential de novo pyrimidine synthesis (Takashima, E., Inaoka, D. K., Osanai, A., Nara, T., Odaka, M., Aoki, T., Inaka, K., Harada, S., and Kita, K. (2002) Mol. Biochem. Parasitol. 122, 189 -200). [ABSTRACT FROM AUTHOR]

Published
2006
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13. ATP Synthesis-coupled and -uncoupled Acetate Production from Acetyl-CoA by Mitochondrial Acetate: Succinate CoA-transferase and Acetyl-CoA Thioesterase in Trypanosoma.

Author

Millerioux, Yoann, Morand, Pauline, Biran, Marc, Mazet, Muriel, Moreau, Patrick, Wargnies, Marion, Ebikeme, Charles, Deramchia, Kamel, Gales, Lara, Portais, Jean-Charles, Boshart, Michael, Franconi, Jean-Michel, and Bringaud, Frédéric

Subjects
*INSECTS, *TRYPANOSOMA, *CYTOSOL, *ESSENTIAL fatty acids, *BIOSYNTHESIS
Abstract

Insect stage trypanosomes use an "acetate shuttle" to transfer mitochondrial acetyl-CoA to the cytosol for the essential fatty acid biosynthesis. The mitochondrial acetate sources are acetate: succinate CoA-transferase (ASCT) and an unknown enzymatic activity. We have identified a gene encoding acetyl-CoA thioesterase (ACH) activity, which is shown to be the second acetate source. First, RNAi-mediated repression of ASCT in the ACH null background abolishes acetate production from glucose, as opposed to both single ASCT and ACH mutants. Second, incorporation of radiolabeled glucose into fatty acids is also abolished in this ACH/ASCT double mutant. ASCT is involved in ATP production, whereas ACH is not, because the ASCT null mutant is ∼1000 times more sensitive to oligomycin, a specific inhibitor of the mitochondrial F0/F1-ATP synthase, than wild-type cells or the ACH null mutant. This was confirmed by RNAi repression of the F0/F1-ATP synthase F1β subunit, which is lethal when performed in the ASCT null background but not in the wild-type cells or the ACH null background. We concluded that acetate is produced from both ASCT and ACH; however, only ASCT is responsible, together with the F0/F1-ATP synthase, for ATP production in the mitochondrion. [ABSTRACT FROM AUTHOR]

Published
2012
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