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von Känel C, Oeljeklaus S, Wenger C, Stettler P, Harsman A, Warscheid B, Schneider A. Intermembrane space-localized TbTim15 is an essential subunit of the single mitochondrial inner membrane protein translocase of trypanosomes. Mol Microbiol 2024; 121:1112-1126. [PMID: 38622999 DOI: 10.1111/mmi.15262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Revised: 03/24/2024] [Accepted: 03/25/2024] [Indexed: 04/17/2024]
Abstract
All mitochondria import >95% of their proteins from the cytosol. This process is mediated by protein translocases in the mitochondrial membranes, whose subunits are generally highly conserved. Most eukaryotes have two inner membrane protein translocases (TIMs) that are specialized to import either presequence-containing or mitochondrial carrier proteins. In contrast, the parasitic protozoan Trypanosoma brucei has a single TIM complex consisting of one conserved and five unique subunits. Here, we identify candidates for new subunits of the TIM or the presequence translocase-associated motor (PAM) using a protein-protein interaction network of previously characterized TIM and PAM subunits. This analysis reveals that the trypanosomal TIM complex contains an additional trypanosomatid-specific subunit, designated TbTim15. TbTim15 is associated with the TIM complex, lacks transmembrane domains, and localizes to the intermembrane space. TbTim15 is essential for procyclic and bloodstream forms of trypanosomes. It contains two twin CX9C motifs and mediates import of both presequence-containing and mitochondrial carrier proteins. While the precise function of TbTim15 in mitochondrial protein import is unknown, our results are consistent with the notion that it may function as an import receptor for the non-canonical trypanosomal TIM complex.
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Affiliation(s)
- Corinne von Känel
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland
| | - Silke Oeljeklaus
- Faculty of Chemistry and Pharmacy, Biochemistry II, Theodor Boveri-Institute, University of Würzburg, Würzburg, Germany
| | - Christoph Wenger
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland
| | - Philip Stettler
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland
| | - Anke Harsman
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland
| | - Bettina Warscheid
- Faculty of Chemistry and Pharmacy, Biochemistry II, Theodor Boveri-Institute, University of Würzburg, Würzburg, Germany
| | - André Schneider
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland
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2
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Rivara-Espasandín M, Palumbo MC, Sosa EJ, Radío S, Turjanski AG, Sotelo-Silveira J, Fernandez Do Porto D, Smircich P. Omics data integration facilitates target selection for new antiparasitic drugs against TriTryp infections. Front Pharmacol 2023; 14:1136321. [PMID: 37089958 PMCID: PMC10115950 DOI: 10.3389/fphar.2023.1136321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Accepted: 03/28/2023] [Indexed: 04/09/2023] Open
Abstract
Introduction:Trypanosoma cruzi, Trypanosoma brucei, and Leishmania spp., commonly referred to as TriTryps, are a group of protozoan parasites that cause important human diseases affecting millions of people belonging to the most vulnerable populations worldwide. Current treatments have limited efficiencies and can cause serious side effects, so there is an urgent need to develop new control strategies. Presently, the identification and prioritization of appropriate targets can be aided by integrative genomic and computational approaches.Methods: In this work, we conducted a genome-wide multidimensional data integration strategy to prioritize drug targets. We included genomic, transcriptomic, metabolic, and protein structural data sources, to delineate candidate proteins with relevant features for target selection in drug development.Results and Discussion: Our final ranked list includes proteins shared by TriTryps and covers a range of biological functions including essential proteins for parasite survival or growth, oxidative stress-related enzymes, virulence factors, and proteins that are exclusive to these parasites. Our strategy found previously described candidates, which validates our approach as well as new proteins that can be attractive targets to consider during the initial steps of drug discovery.
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Affiliation(s)
- Martin Rivara-Espasandín
- Departamento de Genómica, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay
- Departamento de Genética, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
| | - Miranda Clara Palumbo
- Instituto de Cálculo, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Ezequiel J. Sosa
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
- Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales (IQUIBICEN) CONICET, Ciudad Universitaria, Buenos Aires, Argentina
| | - Santiago Radío
- Departamento de Genómica, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay
| | - Adrián G. Turjanski
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
- Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales (IQUIBICEN) CONICET, Ciudad Universitaria, Buenos Aires, Argentina
| | - José Sotelo-Silveira
- Departamento de Genómica, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay
- Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
| | - Dario Fernandez Do Porto
- Instituto de Cálculo, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
- *Correspondence: Dario Fernandez Do Porto, ; Pablo Smircich,
| | - Pablo Smircich
- Departamento de Genómica, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay
- Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
- *Correspondence: Dario Fernandez Do Porto, ; Pablo Smircich,
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Branched chain amino acids catabolism as a source of new drug targets in pathogenic protists. Exp Parasitol 2023; 249:108499. [PMID: 36898495 DOI: 10.1016/j.exppara.2023.108499] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 03/02/2023] [Accepted: 03/05/2023] [Indexed: 03/11/2023]
Abstract
Leucine, isoleucine, and valine, collectively termed Branched Chain Amino Acids (BCAA), are hydrophobic amino acids (AAs) and are essential for most eukaryotes since in these organisms they cannot be biosynthesized and must be supplied by the diet. These AAs are structurally relevant for muscle cells and, of course, important for the protein synthesis process. The metabolism of BCAA and its participation in different biological processes in mammals have been relatively well described. However, for other organisms as pathogenic parasites, the literature is really scarce. Here we review the BCAA catabolism, compile evidence on their relevance for pathogenic eukaryotes with special emphasis on kinetoplastids and highlight unique aspects of this underrated pathway.
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Scattolini A, Lavatelli A, Vacchina P, Lambruschi DA, Mansilla MC, Uttaro AD. Functional characterization of the first lipoyl-relay pathway from a parasitic protozoan. Mol Microbiol 2022; 117:1352-1365. [PMID: 35484915 DOI: 10.1111/mmi.14913] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 04/25/2022] [Accepted: 04/25/2022] [Indexed: 11/30/2022]
Abstract
Lipoic acid (LA) is a sulfur-containing cofactor covalently attached to key enzymes of central metabolism in prokaryotes and eukaryotes. LA can be acquired by scavenging, mediated by a lipoate ligase, or de novo synthesized by a pathway requiring an octanoyltransferase and a lipoate synthase. A more complex pathway, referred to as "lipoyl-relay", requires two additional proteins, GcvH, the glycine cleavage system H subunit, and an amidotransferase. This route was described so far in Bacillus subtilis and related Gram positive bacteria, Saccharomyces cerevisiae, Homo sapiens and Caenorhabditis elegans. Using collections of S. cerevisiae and B. subtilis mutants, defective in LA metabolism, we gathered evidence that allow us to propose for the first time that lipoyl-relay pathways are also present in parasitic protozoa. By a reverse genetic approach, we assigned octanoyltransferase and amidotransferase activity to the products of Tb927.11.9390 (TblipT) and Tb927.8.630 (TblipL) genes of Trypanosoma brucei, respectively. The B. subtilis model allowed us to identify the parasite amidotransferase as the target of lipoate analogues like 8-bromo octanoic acid, explaining the complete loss of protein lipoylation and growth impairment caused by this compound in T. cruzi. This model could be instrumental for the screening of selective and more efficient chemotherapies against trypanosomiases.
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Affiliation(s)
- Albertina Scattolini
- Instituto de Biología Molecular y Celular de Rosario (IBR), Consejo Nacional de Investigaciones Científicas y Técnicas.,Departamento de Microbiología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario. Ocampo y Esmeralda, Predio CONICET (S2000FHQ) Rosario, Argentina
| | - Antonela Lavatelli
- Instituto de Biología Molecular y Celular de Rosario (IBR), Consejo Nacional de Investigaciones Científicas y Técnicas.,Consejo Superior de Investigaciones Científicas, Centre for Research in Agricultural Genomics
| | - Paola Vacchina
- Instituto de Biología Molecular y Celular de Rosario (IBR), Consejo Nacional de Investigaciones Científicas y Técnicas
| | - Daniel A Lambruschi
- Instituto de Biología Molecular y Celular de Rosario (IBR), Consejo Nacional de Investigaciones Científicas y Técnicas
| | - María C Mansilla
- Instituto de Biología Molecular y Celular de Rosario (IBR), Consejo Nacional de Investigaciones Científicas y Técnicas.,Departamento de Microbiología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario. Ocampo y Esmeralda, Predio CONICET (S2000FHQ) Rosario, Argentina
| | - Antonio D Uttaro
- Instituto de Biología Molecular y Celular de Rosario (IBR), Consejo Nacional de Investigaciones Científicas y Técnicas.,Departamento de Microbiología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario. Ocampo y Esmeralda, Predio CONICET (S2000FHQ) Rosario, Argentina
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5
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Ortíz C, Moraca F, Laverriere M, Jordan A, Hamilton N, Comini MA. Glucose 6-Phosphate Dehydrogenase from Trypanosomes: Selectivity for Steroids and Chemical Validation in Bloodstream Trypanosoma brucei. Molecules 2021; 26:E358. [PMID: 33445584 PMCID: PMC7826790 DOI: 10.3390/molecules26020358] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2020] [Revised: 01/07/2021] [Accepted: 01/09/2021] [Indexed: 11/17/2022] Open
Abstract
Glucose 6-phosphate dehydrogenase (G6PDH) fulfills an essential role in cell physiology by catalyzing the production of NADPH+ and of a precursor for the de novo synthesis of ribose 5-phosphate. In trypanosomatids, G6PDH is essential for in vitro proliferation, antioxidant defense and, thereby, drug resistance mechanisms. So far, 16α-brominated epiandrosterone represents the most potent hit targeting trypanosomal G6PDH. Here, we extended the investigations on this important drug target and its inhibition by using a small subset of androstane derivatives. In Trypanosoma cruzi, immunofluorescence revealed a cytoplasmic distribution of G6PDH and the absence of signal in major organelles. Cytochemical assays confirmed parasitic G6PDH as the molecular target of epiandrosterone. Structure-activity analysis for a set of new (dehydro)epiandrosterone derivatives revealed that bromination at position 16α of the cyclopentane moiety yielded more potent T. cruzi G6PDH inhibitors than the corresponding β-substituted analogues. For the 16α brominated compounds, the inclusion of an acetoxy group at position 3 either proved detrimental or enhanced the activity of the epiandrosterone or the dehydroepiandrosterone derivatives, respectively. Most derivatives presented single digit μM EC50 against infective T. brucei and the killing mechanism involved an early thiol-redox unbalance. This data suggests that infective African trypanosomes lack efficient NADPH+-synthesizing pathways, beyond the Pentose Phosphate, to maintain thiol-redox homeostasis.
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Affiliation(s)
- Cecilia Ortíz
- Redox Biology of Trypanosomes, Institut Pasteur de Montevideo, Mataojo 2020, Montevideo 11400, Uruguay;
| | - Francesca Moraca
- Dipartimento di Biotecnologie, Chimica e Farmacia, Università degli Studi di Siena, Via Aldo Moro 2, 53100 Siena, Italy;
| | - Marc Laverriere
- Instituto de Investigaciones Biotecnológicas, Instituto Tecnológico de Chascomus (IIB-INTECH, UNSAM-CONICET), Av. General Paz 5445, INTI, San Martín 1650, Pcia de Buenos Aires, Argentina;
| | - Allan Jordan
- Drug Discovery Unit, Cancer Research UK Manchester Institute, University of Manchester, Alderley Park, Macclesfield SK10 4TG, UK; (A.J.); (N.H.)
| | - Niall Hamilton
- Drug Discovery Unit, Cancer Research UK Manchester Institute, University of Manchester, Alderley Park, Macclesfield SK10 4TG, UK; (A.J.); (N.H.)
| | - Marcelo A. Comini
- Redox Biology of Trypanosomes, Institut Pasteur de Montevideo, Mataojo 2020, Montevideo 11400, Uruguay;
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Bogacz M, Dirdjaja N, Wimmer B, Habich C, Krauth-Siegel RL. The mitochondrial peroxiredoxin displays distinct roles in different developmental stages of African trypanosomes. Redox Biol 2020; 34:101547. [PMID: 32388269 PMCID: PMC7218024 DOI: 10.1016/j.redox.2020.101547] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 04/11/2020] [Accepted: 04/20/2020] [Indexed: 12/26/2022] Open
Abstract
Hydroperoxide reduction in African trypanosomes relies on 2-Cys-peroxiredoxins (Prxs) and glutathione peroxidase-type enzymes (Pxs) which both obtain their reducing equivalents from the trypanothione/tryparedoxin couple and thus act as tryparedoxin peroxidases. While the cytosolic forms of the peroxidases are essential, the mitochondrial mPrx and Px III appear dispensable in bloodstream Trypanosoma brucei. This led to the suggestion that in this developmental stage which is characterized by a mitochondrion that lacks an active respiratory chain, only one of the two peroxidases might be required. Here we show that bloodstream cells in which the Px III gene is deleted and mPrx is down-regulated by RNA interference, proliferate as the parental cells indicating that both mitochondrial peroxidases are dispensable. However, when we raised the culture temperature to 39 °C, mPrx-depleted cells died indicating that under conditions mimicking a fever situation in the mammalian host, the protein becomes essential. In contrast, depletion of mPrx in insect stage procyclic T. brucei causes a proliferation defect under standard conditions at 27 °C, in the absence of any stress. In the absence of mPrx, a tryparedoxin-coupled roGFP2 biosensor expressed in the mitochondrial matrix is unable to respond to antimycin A treatment. Thus mPrx reduces mitochondrial H2O2 with the generation of trypanothione disulfide and acts as peroxidase. However, mPrx-depleted procyclic cells neither display any alteration in the cytosolic or mitochondrial trypanothione redox state nor increased sensitivity towards exogenous oxidative stressors suggesting that the peroxidase activity is not the crucial physiological function. After prolonged mPrx-depletion, the cells almost stop proliferation and display a highly elongated shape and diminished MitoTracker Red staining. In contrast to the situation in the mammalian bloodstream T. brucei and Leishmania, mPrx appears to play a constitutive role for the morphology, mitochondrial function and proliferation of the insect stage of African trypanosomes. In bloodstream T. brucei, both mitochondrial tryparedoxin peroxidases are dispensable. Heat-stressed bloodstream cells require the mitochondrial peroxiredoxin (mPrx). In procyclic (PC) T. brucei, mPrx plays a constitutive role for proliferation. Lack of mPrx affects the structure and mitochondrial membrane potential of PC cells.
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Affiliation(s)
- Marta Bogacz
- Biochemie-Zentrum der Universität Heidelberg, Im Neuenheimer Feld 328, 69120, Heidelberg, Germany
| | - Natalie Dirdjaja
- Biochemie-Zentrum der Universität Heidelberg, Im Neuenheimer Feld 328, 69120, Heidelberg, Germany
| | - Benedikt Wimmer
- Biochemie-Zentrum der Universität Heidelberg, Im Neuenheimer Feld 328, 69120, Heidelberg, Germany
| | - Carina Habich
- Biochemie-Zentrum der Universität Heidelberg, Im Neuenheimer Feld 328, 69120, Heidelberg, Germany
| | - R Luise Krauth-Siegel
- Biochemie-Zentrum der Universität Heidelberg, Im Neuenheimer Feld 328, 69120, Heidelberg, Germany.
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7
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Ebersoll S, Bogacz M, Günter LM, Dick TP, Krauth-Siegel RL. A tryparedoxin-coupled biosensor reveals a mitochondrial trypanothione metabolism in trypanosomes. eLife 2020; 9:53227. [PMID: 32003744 PMCID: PMC7046469 DOI: 10.7554/elife.53227] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Accepted: 01/29/2020] [Indexed: 12/12/2022] Open
Abstract
Trypanosomes have a trypanothione redox metabolism that provides the reducing equivalents for numerous essential processes, most being mediated by tryparedoxin (Tpx). While the biosynthesis and reduction of trypanothione are cytosolic, the molecular basis of the thiol redox homeostasis in the single mitochondrion of these parasites has remained largely unknown. Here we expressed Tpx-roGFP2, roGFP2-hGrx1 or roGFP2 in either the cytosol or mitochondrion of Trypanosoma brucei. We show that the novel Tpx-roGFP2 is a superior probe for the trypanothione redox couple and that the mitochondrial matrix harbors a trypanothione system. Inhibition of trypanothione biosynthesis by the anti-trypanosomal drug Eflornithine impairs the ability of the cytosol and mitochondrion to cope with exogenous oxidative stresses, indicating a direct link between both thiol systems. Tpx depletion abolishes the cytosolic, but only partially affects the mitochondrial sensor response to H2O2. This strongly suggests that the mitochondrion harbors some Tpx and, another, as yet unidentified, oxidoreductase.
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Affiliation(s)
| | - Marta Bogacz
- Biochemie-Zentrum der Universität Heidelberg, Heidelberg, Germany
| | - Lina M Günter
- Biochemie-Zentrum der Universität Heidelberg, Heidelberg, Germany
| | - Tobias P Dick
- Division of Redox Regulation, DKFZ-ZMBH Alliance, German Cancer Research Center (DKFZ), Heidelberg, Germany
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8
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Currier RB, Ulrich K, Leroux AE, Dirdjaja N, Deambrosi M, Bonilla M, Ahmed YL, Adrian L, Antelmann H, Jakob U, Comini MA, Krauth-Siegel RL. An essential thioredoxin-type protein of Trypanosoma brucei acts as redox-regulated mitochondrial chaperone. PLoS Pathog 2019; 15:e1008065. [PMID: 31557263 PMCID: PMC6783113 DOI: 10.1371/journal.ppat.1008065] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 10/08/2019] [Accepted: 09/02/2019] [Indexed: 12/22/2022] Open
Abstract
Most known thioredoxin-type proteins (Trx) participate in redox pathways, using two highly conserved cysteine residues to catalyze thiol-disulfide exchange reactions. Here we demonstrate that the so far unexplored Trx2 from African trypanosomes (Trypanosoma brucei) lacks protein disulfide reductase activity but functions as an effective temperature-activated and redox-regulated chaperone. Immunofluorescence microscopy and fractionated cell lysis revealed that Trx2 is located in the mitochondrion of the parasite. RNA-interference and gene knock-out approaches showed that depletion of Trx2 impairs growth of both mammalian bloodstream and insect stage procyclic parasites. Procyclic cells lacking Trx2 stop proliferation under standard culture conditions at 27°C and are unable to survive prolonged exposure to 37°C, indicating that Trx2 plays a vital role that becomes augmented under heat stress. Moreover, we found that Trx2 contributes to the in vivo infectivity of T. brucei. Remarkably, a Trx2 version, in which all five cysteines were replaced by serine residues, complements for the wildtype protein in conditional knock-out cells and confers parasite infectivity in the mouse model. Characterization of the recombinant protein revealed that Trx2 can coordinate an iron sulfur cluster and is highly sensitive towards spontaneous oxidation. Moreover, we discovered that both wildtype and mutant Trx2 protect other proteins against thermal aggregation and preserve their ability to refold upon return to non-stress conditions. Activation of the chaperone function of Trx2 appears to be triggered by temperature-mediated structural changes and inhibited by oxidative disulfide bond formation. Our studies indicate that Trx2 acts as a novel chaperone in the unique single mitochondrion of T. brucei and reveal a new perspective regarding the physiological function of thioredoxin-type proteins in trypanosomes.
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Affiliation(s)
- Rachel B. Currier
- Biochemie-Zentrum der Universität Heidelberg (BZH), Heidelberg, Germany
| | - Kathrin Ulrich
- Biochemie-Zentrum der Universität Heidelberg (BZH), Heidelberg, Germany
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan, United States of America
| | | | - Natalie Dirdjaja
- Biochemie-Zentrum der Universität Heidelberg (BZH), Heidelberg, Germany
| | - Matías Deambrosi
- Group Redox Biology of Trypanosomes, Institut Pasteur de Montevideo, Montevideo, Uruguay
| | - Mariana Bonilla
- Group Redox Biology of Trypanosomes, Institut Pasteur de Montevideo, Montevideo, Uruguay
- Laboratorio de Fisicoquímica Biológica, Instituto de Química Biológica, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
| | | | - Lorenz Adrian
- Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research–UFZ, Leipzig, Germany
- Fachgebiet Geobiotechnologie, Technische Universität Berlin, Berlin, Germany
| | - Haike Antelmann
- Institut für Biologie-Mikrobiologie, Freie Universität Berlin, Berlin, Germany
| | - Ursula Jakob
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Marcelo A. Comini
- Group Redox Biology of Trypanosomes, Institut Pasteur de Montevideo, Montevideo, Uruguay
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9
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Cullia G, Tamborini L, Conti P, De Micheli C, Pinto A. Folates in Trypanosoma brucei
: Achievements and Opportunities. ChemMedChem 2018; 13:2150-2158. [DOI: 10.1002/cmdc.201800500] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Indexed: 12/11/2022]
Affiliation(s)
- Gregorio Cullia
- Institute of Biomolecules Max Mousseron (IBMM); UMR5247; CNRS; University of Montpellier; ENSCM; Place Eugène Battaillon 34095 Montpellier cedex 5 France
| | - Lucia Tamborini
- Department of Pharmaceutical Sciences (DISFARM); University of Milan; via Luigi Mangiagalli 25 20133 Milano Italy
| | - Paola Conti
- Department of Pharmaceutical Sciences (DISFARM); University of Milan; via Luigi Mangiagalli 25 20133 Milano Italy
| | - Carlo De Micheli
- Department of Pharmaceutical Sciences (DISFARM); University of Milan; via Luigi Mangiagalli 25 20133 Milano Italy
| | - Andrea Pinto
- Department of Food Environmental and Nutritional Sciences; University of Milan; via Giovanni Celoria 2 20133 Milano Italy
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The Uptake and Metabolism of Amino Acids, and Their Unique Role in the Biology of Pathogenic Trypanosomatids. Pathogens 2018; 7:pathogens7020036. [PMID: 29614775 PMCID: PMC6027508 DOI: 10.3390/pathogens7020036] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 03/28/2018] [Accepted: 03/29/2018] [Indexed: 01/24/2023] Open
Abstract
Trypanosoma brucei, as well as Trypanosoma cruzi and more than 20 species of the genus Leishmania, form a group of flagellated protists that threaten human health. These organisms are transmitted by insects that, together with mammals, are their natural hosts. This implies that during their life cycles each of them faces environments with different physical, chemical, biochemical, and biological characteristics. In this work we review how amino acids are obtained from such environments, how they are metabolized, and how they and some of their intermediate metabolites are used as a survival toolbox to cope with the different conditions in which these parasites should establish the infections in the insects and mammalian hosts.
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Chiranjivi AK, Dubey VK. Dihydrolipoamide dehydrogenase from Leishmania donovani: New insights through biochemical characterization. Int J Biol Macromol 2018; 112:1241-1247. [PMID: 29466712 DOI: 10.1016/j.ijbiomac.2018.02.112] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Revised: 02/13/2018] [Accepted: 02/16/2018] [Indexed: 02/06/2023]
Abstract
Dihydrolipoamide dehydrogenase (DLDH) regulates many crucial metabolic pathways as a multi-enzyme complex. Leishmania donovani dihydrolipoamide dehydrogenase (LdDLDH) has two variants present on two different chromosomes with very less sequence similarities. In the current study, we cloned both the variants in pET28a (+) vector and expressed in Rosetta-gami (DE3) E. coli strain. Expressed proteins were finally purified from pellets using Ni-NTA affinity chromatography. Purified enzymes were biochemically characterized and different kinetic parameters were studied. Both the variants showed maximum activity in pH range of 7.0-8.0 and temperature 50±5°C in the physiological direction. The estimated Km for dihydrolipoamide (DLA) and NAD+ were 2.7±0.48mM and 171.23±11.59μM respectively for variant 1 (LdBPK291950.1). In the case of variant 2 (LdBPK323510.1), Km values for DLA and NAD+ were found to be 829.85±37μM and 226±1.56μM respectively. The variant 2 was more efficient in terms of activity. While both the forms of the enzymes showed diaphorase activity, variant 1 was found to be better. Sequence dissimilarities of both forms were analyzed for biological insights.
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Affiliation(s)
- Adarsh Kumar Chiranjivi
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Assam 781039, India
| | - Vikash Kumar Dubey
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Assam 781039, India.
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12
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Vacchina P, Lambruschi DA, Uttaro AD. Lipoic acid metabolism in Trypanosoma cruzi as putative target for chemotherapy. Exp Parasitol 2018; 186:17-23. [PMID: 29409741 DOI: 10.1016/j.exppara.2018.01.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2016] [Revised: 01/12/2018] [Accepted: 01/30/2018] [Indexed: 11/30/2022]
Abstract
Lipoic acid (LA) is a cofactor of relevant enzymatic complexes including the glycine cleave system and 2-ketoacid dehydrogenases. Intervention on LA de novo synthesis or salvage could have pleiotropic deleterious effect in cells, making both pathways attractive for chemotherapy. We show that Trypanosoma cruzi was susceptible to treatment with LA analogues. 8-Bromo-octanic acid (BrO) inhibited the growth of epimastigote forms of both Dm28c and CL Brener strains, although only at high (chemotherapeutically irrelevant) concentrations. The methyl ester derivative MBrO, was much more effective, with EC50 values one order of magnitude lower (62-66 μM). LA did not bypass the toxic effect of its analogues. Small monocarboxylic acids appear to be poorly internalized by T. cruzi: [14C]-octanoic acid was taken up 12 fold less efficiently than [14C]-palmitic acid. Western blot analysis of lipoylated proteins allowed the detection of the E2 subunits of pyruvate dehydrogenase (PDH), branched chain 2-ketoacid dehydrogenase and 2-ketoglutarate dehydrogenase complexes. Growth of parasites in medium with 10 fold lower glucose content, notably increased PDH activity and the level of its lipoylated E2 subunit. Treatment with BrO (1 mM) and MBrO (0.1 mM) completely inhibited E2 lipoylation and all three dehydrogenases activities. These observations indicate the lack of specific transporters for octanoic acid and most probably also for BrO and LA, which is in agreement with the lack of a LA salvage pathway, as previously suggested for T. brucei. They also indicate that the LA synthesis/protein lipoylation pathway could be a valid target for drug intervention. Moreover, the free LA available in the host would not interfere with such chemotherapeutic treatments.
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Affiliation(s)
- Paola Vacchina
- Instituto de Biología Molecular y Celular de Rosario (IBR), CONICET, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Daniel A Lambruschi
- Instituto de Biología Molecular y Celular de Rosario (IBR), CONICET, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Antonio D Uttaro
- Instituto de Biología Molecular y Celular de Rosario (IBR), CONICET, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina.
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Ebersoll S, Musunda B, Schmenger T, Dirdjaja N, Bonilla M, Manta B, Ulrich K, Comini MA, Krauth-Siegel RL. A glutaredoxin in the mitochondrial intermembrane space has stage-specific functions in the thermo-tolerance and proliferation of African trypanosomes. Redox Biol 2018; 15:532-547. [PMID: 29413965 PMCID: PMC5975080 DOI: 10.1016/j.redox.2018.01.011] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Accepted: 01/23/2018] [Indexed: 12/30/2022] Open
Abstract
Trypanosoma brucei glutaredoxin 2 (Grx2) is a dithiol glutaredoxin that is specifically located in the mitochondrial intermembrane space. Bloodstream form parasites lacking Grx2 or both, Grx2 and the cytosolic Grx1, are viable in vitro and infectious to mice suggesting that neither oxidoreductase is needed for survival or infectivity to mammals. A 37 °C to 39 °C shift changes the cellular redox milieu of bloodstream cells to more oxidizing conditions and induces a significantly stronger growth arrest in wildtype parasites compared to the mutant cells. Grx2-deficient cells ectopically expressing the wildtype form of Grx2 with its C31QFC34 active site, but not the C34S mutant, regain the sensitivity of the parental strain, indicating that the physiological role of Grx2 requires both active site cysteines. In the procyclic insect stage of the parasite, Grx2 is essential. Both alleles can be replaced if procyclic cells ectopically express authentic or C34S, but not C31S/C34S Grx2, pointing to a redox role that relies on a monothiol mechanism. RNA-interference against Grx2 causes a virtually irreversible proliferation defect. The cells adopt an elongated morphology but do not show any significant alteration in the cell cycle. The growth retardation is attenuated by high glucose concentrations. Under these conditions, procyclic cells obtain ATP by substrate level phosphorylation suggesting that Grx2 might regulate a respiratory chain component. Bloodstream T. brucei lacking glutaredoxin 2 are fully viable in vitro and in vivo. A temperature rise shifts the cellular redox state to more oxidizing conditions. Glutaredoxin 2-deficiency confers bloodstream cells with thermo-tolerance. The insect stage requires redox-active glutaredoxin 2 for viability and morphology.
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Affiliation(s)
- Samantha Ebersoll
- Biochemie-Zentrum der Universität Heidelberg, Im Neuenheimer Feld 328, 69120 Heidelberg, Germany
| | - Blessing Musunda
- Biochemie-Zentrum der Universität Heidelberg, Im Neuenheimer Feld 328, 69120 Heidelberg, Germany
| | - Torsten Schmenger
- Biochemie-Zentrum der Universität Heidelberg, Im Neuenheimer Feld 328, 69120 Heidelberg, Germany
| | - Natalie Dirdjaja
- Biochemie-Zentrum der Universität Heidelberg, Im Neuenheimer Feld 328, 69120 Heidelberg, Germany
| | - Mariana Bonilla
- Group Redox Biology of Trypanosomes, Institut Pasteur de Montevideo, Mataojo 2020, CP 11400, Montevideo, Uruguay
| | - Bruno Manta
- Group Redox Biology of Trypanosomes, Institut Pasteur de Montevideo, Mataojo 2020, CP 11400, Montevideo, Uruguay
| | - Kathrin Ulrich
- Biochemie-Zentrum der Universität Heidelberg, Im Neuenheimer Feld 328, 69120 Heidelberg, Germany
| | - Marcelo A Comini
- Group Redox Biology of Trypanosomes, Institut Pasteur de Montevideo, Mataojo 2020, CP 11400, Montevideo, Uruguay
| | - R Luise Krauth-Siegel
- Biochemie-Zentrum der Universität Heidelberg, Im Neuenheimer Feld 328, 69120 Heidelberg, Germany.
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Franco J, Scarone L, Comini MA. Drugs and Drug Resistance in African and American Trypanosomiasis. ANNUAL REPORTS IN MEDICINAL CHEMISTRY 2018. [DOI: 10.1016/bs.armc.2018.08.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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15
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Zhuo Y, Cordeiro CD, Hekmatyar SK, Docampo R, Prestegard JH. Dynamic nuclear polarization facilitates monitoring of pyruvate metabolism in Trypanosoma brucei. J Biol Chem 2017; 292:18161-18168. [PMID: 28887303 DOI: 10.1074/jbc.m117.807495] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Indexed: 11/06/2022] Open
Abstract
Dynamic nuclear polarization provides sensitivity improvements that make NMR a viable method for following metabolic conversions in real time. There are now many in vivo applications to animal systems and even to diagnosis of human disease. However, application to microbial systems is rare. Here we demonstrate its application to the pathogenic protozoan, Trypanosoma brucei, using hyperpolarized 13C1 pyruvate as a substrate and compare the parasite metabolism with that of commonly cultured mammalian cell lines, HEK-293 and Hep-G2. Metabolic differences between insect and bloodstream forms of T. brucei were also investigated. Significant differences are noted with respect to lactate, alanine, and CO2 production. Conversion of pyruvate to CO2 in the T. brucei bloodstream form provides new support for the presence of an active pyruvate dehydrogenase in this stage.
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Affiliation(s)
- You Zhuo
- From the Complex Carbohydrate Research Center
| | - Ciro D Cordeiro
- the Center for Tropical and Emerging Global Diseases, and.,the Department of Cellular Biology, University of Georgia, Athens, Georgia 30602
| | | | - Roberto Docampo
- the Center for Tropical and Emerging Global Diseases, and.,the Department of Cellular Biology, University of Georgia, Athens, Georgia 30602
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16
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Charting organellar importomes by quantitative mass spectrometry. Nat Commun 2017; 8:15272. [PMID: 28485388 PMCID: PMC5436138 DOI: 10.1038/ncomms15272] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Accepted: 03/15/2017] [Indexed: 11/08/2022] Open
Abstract
Protein import into organelles is essential for all eukaryotes and facilitated by multi-protein translocation machineries. Analysing whether a protein is transported into an organelle is largely restricted to single constituents. This renders knowledge about imported proteins incomplete, limiting our understanding of organellar biogenesis and function. Here we introduce a method that enables charting an organelle's importome. The approach relies on inducible RNAi-mediated knockdown of an essential subunit of a translocase to impair import and quantitative mass spectrometry. To highlight its potential, we established the mitochondrial importome of Trypanosoma brucei, comprising 1,120 proteins including 331 new candidates. Furthermore, the method allows for the identification of proteins with dual or multiple locations and the substrates of distinct protein import pathways. We demonstrate the specificity and versatility of this ImportOmics method by targeting import factors in mitochondria and glycosomes, which demonstrates its potential for globally studying protein import and inventories of organelles. Knowing the specific protein content of individual organelles is necessary for an integrated understanding of cellular physiology. Here the authors describe a mass spectrometry-based approach to identify the substrates of distinct protein import pathways and define organellar proteomes.
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17
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Zimmermann H, Subota I, Batram C, Kramer S, Janzen CJ, Jones NG, Engstler M. A quorum sensing-independent path to stumpy development in Trypanosoma brucei. PLoS Pathog 2017; 13:e1006324. [PMID: 28394929 PMCID: PMC5398725 DOI: 10.1371/journal.ppat.1006324] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Revised: 04/20/2017] [Accepted: 03/29/2017] [Indexed: 11/19/2022] Open
Abstract
For persistent infections of the mammalian host, African trypanosomes limit their population size by quorum sensing of the parasite-excreted stumpy induction factor (SIF), which induces development to the tsetse-infective stumpy stage. We found that besides this cell density-dependent mechanism, there exists a second path to the stumpy stage that is linked to antigenic variation, the main instrument of parasite virulence. The expression of a second variant surface glycoprotein (VSG) leads to transcriptional attenuation of the VSG expression site (ES) and immediate development to tsetse fly infective stumpy parasites. This path is independent of SIF and solely controlled by the transcriptional status of the ES. In pleomorphic trypanosomes varying degrees of ES-attenuation result in phenotypic plasticity. While full ES-attenuation causes irreversible stumpy development, milder attenuation may open a time window for rescuing an unsuccessful antigenic switch, a scenario that so far has not been considered as important for parasite survival.
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Affiliation(s)
- Henriette Zimmermann
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, Würzburg, Germany
| | - Ines Subota
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, Würzburg, Germany
| | - Christopher Batram
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, Würzburg, Germany
| | - Susanne Kramer
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, Würzburg, Germany
| | - Christian J. Janzen
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, Würzburg, Germany
| | - Nicola G. Jones
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, Würzburg, Germany
| | - Markus Engstler
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, Würzburg, Germany
- * E-mail:
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18
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dos Santos PF, Moreira DS, Baba EH, Volpe CM, Ruiz JC, Romanha AJ, Murta SM. Molecular characterization of lipoamide dehydrogenase gene in Trypanosoma cruzi populations susceptible and resistant to benznidazole. Exp Parasitol 2016; 170:1-9. [DOI: 10.1016/j.exppara.2016.08.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Revised: 07/18/2016] [Accepted: 08/22/2016] [Indexed: 01/15/2023]
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19
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Surve SV, Jensen BC, Heestand M, Mazet M, Smith TK, Bringaud F, Parsons M, Schnaufer A. NADH dehydrogenase of Trypanosoma brucei is important for efficient acetate production in bloodstream forms. Mol Biochem Parasitol 2016; 211:57-61. [PMID: 27717801 PMCID: PMC5225879 DOI: 10.1016/j.molbiopara.2016.10.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Revised: 09/29/2016] [Accepted: 10/03/2016] [Indexed: 11/29/2022]
Abstract
Various genetic mutants of NDH2 were created in bloodstream form Trypanosoma brucei. NDH2 null mutants showed a substantial reduction in growth. NDH2 ablation in a complex I deficient background led to severe growth restriction. Upon prolonged culture, parasites partially compensated for NDH2 deficiency. Loss of NDH2 led to reduced acetate, potentially contributing to the growth defect.
In the slender bloodstream form, Trypanosoma brucei mitochondria are repressed for many functions. Multiple components of mitochondrial complex I, NADH:ubiquinone oxidoreductase, are expressed in this stage, but electron transfer through complex I is not essential. Here we investigate the role of the parasite’s second NADH:ubiquinone oxidoreductase, NDH2, which is composed of a single subunit that also localizes to the mitochondrion. While inducible knockdown of NDH2 had a modest growth effect in bloodstream forms, NDH2 null mutants, as well as inducible knockdowns in a complex I deficient background, showed a greater reduction in growth. Altering the NAD+/NADH balance would affect numerous processes directly and indirectly, including acetate production. Indeed, loss of NDH2 led to reduced levels of acetate, which is required for several essential pathways in bloodstream form T. brucei and which may have contributed to the observed growth defect. In conclusion our study shows that NDH2 is important, but not essential, in proliferating bloodstream forms of T. brucei, arguing that the mitochondrial NAD+/NADH balance is important in this stage, even though the mitochondrion itself is not actively engaged in the generation of ATP.
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Affiliation(s)
- Sachin V Surve
- Center for Infectious Disease Research (Formerly Seattle Biomedical Research Institute), 307 Westlake Ave. N., Seattle, WA, 98109, USA
| | - Bryan C Jensen
- Center for Infectious Disease Research (Formerly Seattle Biomedical Research Institute), 307 Westlake Ave. N., Seattle, WA, 98109, USA
| | - Meredith Heestand
- Center for Infectious Disease Research (Formerly Seattle Biomedical Research Institute), 307 Westlake Ave. N., Seattle, WA, 98109, USA
| | - Muriel Mazet
- Centre de Résonance Magnétique des Systèmes Biologiques (RMSB), UMR5536, Université de Bordeaux, CNRS, Bordeaux, France
| | - Terry K Smith
- Biomedical Sciences Research Complex, University of St Andrews, North Haugh, St. Andrews KY16 9ST, United Kingdom
| | - Frédéric Bringaud
- Centre de Résonance Magnétique des Systèmes Biologiques (RMSB), UMR5536, Université de Bordeaux, CNRS, Bordeaux, France
| | - Marilyn Parsons
- Center for Infectious Disease Research (Formerly Seattle Biomedical Research Institute), 307 Westlake Ave. N., Seattle, WA, 98109, USA; Dept. of Global Health, University of Washington, Seattle, WA, 98195, USA.
| | - Achim Schnaufer
- Institute of Immunology & Infection Research and Centre of Immunity, Infection & Evolution, The University of Edinburgh, Edinburgh, EH9 3FL, United Kingdom.
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20
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Eze AA, Gould MK, Munday JC, Tagoe DNA, Stelmanis V, Schnaufer A, De Koning HP. Reduced Mitochondrial Membrane Potential Is a Late Adaptation of Trypanosoma brucei brucei to Isometamidium Preceded by Mutations in the γ Subunit of the F1Fo-ATPase. PLoS Negl Trop Dis 2016; 10:e0004791. [PMID: 27518185 PMCID: PMC4982688 DOI: 10.1371/journal.pntd.0004791] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Accepted: 05/30/2016] [Indexed: 11/19/2022] Open
Abstract
Background Isometamidium is the main prophylactic drug used to prevent the infection of livestock with trypanosomes that cause Animal African Trypanosomiasis. As well as the animal infective trypanosome species, livestock can also harbor the closely related human infective subspecies T. b. gambiense and T. b. rhodesiense. Resistance to isometamidium is a growing concern, as is cross-resistance to the diamidine drugs diminazene and pentamidine. Methodology/Principal Findings Two isometamidium resistant Trypanosoma brucei clones were generated (ISMR1 and ISMR15), being 7270- and 16,000-fold resistant to isometamidium, respectively, which retained their ability to grow in vitro and establish an infection in mice. Considerable cross-resistance was shown to ethidium bromide and diminazene, with minor cross-resistance to pentamidine. The mitochondrial membrane potentials of both resistant cell lines were significantly reduced compared to the wild type. The net uptake rate of isometamidium was reduced 2-3-fold but isometamidium efflux was similar in wild-type and resistant lines. Fluorescence microscopy and PCR analysis revealed that ISMR1 and ISMR15 had completely lost their kinetoplast DNA (kDNA) and both lines carried a mutation in the nuclearly encoded γ subunit gene of F1 ATPase, truncating the protein by 22 amino acids. The mutation compensated for the loss of the kinetoplast in bloodstream forms, allowing near-normal growth, and conferred considerable resistance to isometamidium and ethidium as well as significant resistance to diminazene and pentamidine, when expressed in wild type trypanosomes. Subsequent exposure to either isometamidium or ethidium led to rapid loss of kDNA and a further increase in isometamidium resistance. Conclusions/Significance Sub-lethal exposure to isometamidium gives rise to viable but highly resistant trypanosomes that, depending on sub-species, are infective to humans and cross-resistant to at least some diamidine drugs. The crucial mutation is in the F1 ATPase γ subunit, which allows loss of kDNA and results in a reduction of the mitochondrial membrane potential. Isometamidium is the only prophylactic treatment of Animal African Trypanosomiasis, a wasting disease of livestock and domestic animals in sub-Saharan Africa. Unfortunately resistance threatens the continued utility of this drug after decades of use. Not only does this disease have severe impacts on agriculture, but some subspecies of Trypanosoma brucei are human-infective as well (causing sleeping sickness) and there is concern that cross-resistance with trypanocides of the diamidine class could further undermine treatment of both veterinary and human infections. It is therefore essential to understand the mechanism of isometamidium resistance and the likelihood for cross-resistance with other first-line trypanocides. Here, we report that isometamidium resistance can be caused by a mutation in an important mitochondrial protein, the γ subunit of the F1 ATPase, and that this mutation alone is sufficient for high levels of resistance, cross-resistance to various drugs, and a strongly reduced mitochondrial membrane potential. This report will for the first time enable a structural assessment of isometamidium resistance genes in T. brucei spp.
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Affiliation(s)
- Anthonius A. Eze
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Matthew K. Gould
- Institute for Immunology and Infection Research and Centre for Immunity, Infection and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Jane C. Munday
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Daniel N. A. Tagoe
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
- Wellcome Trust Centre for Molecular Parasitology, University of Glasgow, Glasgow, United Kingdom
| | - Valters Stelmanis
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Achim Schnaufer
- Institute for Immunology and Infection Research and Centre for Immunity, Infection and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Harry P. De Koning
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
- * E-mail:
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21
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Leishmania donovani Aurora kinase: A promising therapeutic target against visceral leishmaniasis. Biochim Biophys Acta Gen Subj 2016; 1860:1973-88. [PMID: 27288586 DOI: 10.1016/j.bbagen.2016.06.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Revised: 06/02/2016] [Accepted: 06/06/2016] [Indexed: 01/04/2023]
Abstract
BACKGROUND Aurora kinases are key mitotic kinases executing multiple aspects of eukaryotic cell-division. The apicomplexan homologs being essential for survival, suggest that the Leishmania homolog, annotated LdAIRK, may be equally important. METHODS Bioinformatics, stage-specific immunofluorescence microscopy, immunoblotting, RT-PCR, molecular docking, in-vitro kinase assay, anti-leishmanial activity assays, flow cytometry, fluorescence microscopy. RESULTS Ldairk expression is seen to vary as the cell-cycle progresses from G1 through S and finally G2M and cytokinesis. Kinetic studies demonstrate their enzymatic activity exhibiting a Km and Vmax of 6.12μM and 82.9pmoles·min(-1)mg(-1) respectively against ATP using recombinant Leishmania donovani H3, its physiological substrate. Due to the failure of LdAIRK-/+ knock-out parasites to survive, we adopted a chemical knock-down approach. Based on the conservation of key active site residues, three mammalian Aurora kinase inhibitors were investigated to evaluate their potential as inhibitors of LdAIRK activity. Interestingly, the cell-cycle progressed unhindered, despite treatment with GSK-1070916 or Barasertib, inhibitors with greater potencies for the ATP-binding pocket compared to Hesperadin, which at nanomolar concentrations, severely compromised viability at IC50s 105.9 and 36.4nM for promastigotes and amastigotes, respectively. Cell-cycle and morphological studies implicated their role in both mitosis and cytokinesis. CONCLUSION We identified an Aurora kinase homolog in L. donovani implicated in cell-cycle progression, whose inhibition led to aberrant changes in cell-cycle progression and reduced viability. GENERAL SIGNIFICANCE Human homologs being actively pursued drug targets and the observations with LdAIRK in both promastigotes and amastigotes suggest their potential as therapeutic-targets. Importantly, our results encourage the exploration of other proteins identified herein as potential novel drug targets.
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22
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Selenoproteins of African trypanosomes are dispensable for parasite survival in a mammalian host. Mol Biochem Parasitol 2016; 206:13-9. [DOI: 10.1016/j.molbiopara.2016.03.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Revised: 03/03/2016] [Accepted: 03/04/2016] [Indexed: 01/12/2023]
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Štáfková J, Mach J, Biran M, Verner Z, Bringaud F, Tachezy J. Mitochondrial pyruvate carrier in Trypanosoma brucei. Mol Microbiol 2016; 100:442-56. [PMID: 26748989 DOI: 10.1111/mmi.13325] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/06/2016] [Indexed: 12/30/2022]
Abstract
Pyruvate is a key product of glycolysis that regulates the energy metabolism of cells. In Trypanosoma brucei, the causative agent of sleeping sickness, the fate of pyruvate varies dramatically during the parasite life cycle. In bloodstream forms, pyruvate is mainly excreted, whereas in tsetse fly forms, pyruvate is metabolized in mitochondria yielding additional ATP molecules. The character of the molecular machinery that mediates pyruvate transport across mitochondrial membrane was elusive until the recent discovery of mitochondrial pyruvate carrier (MPC) in yeast and mammals. Here, we characterized pyruvate import into mitochondrion of T. brucei. We identified mpc1 and mpc2 homologs in the T. brucei genome with attributes of MPC protein family and we demonstrated that both proteins are present in the mitochondrial membrane of the parasite. Investigations of mpc1 or mpc2 gene knock-out cells proved that T. brucei MPC1/2 proteins facilitate mitochondrial pyruvate transport. Interestingly, MPC is expressed not only in procyclic trypanosomes with fully activated mitochondria but also in bloodstream trypanosomes in which most of pyruvate is excreted. Moreover, MPC appears to be essential for bloodstream forms, supporting the recently emerging picture that the functions of mitochondria in bloodstream forms are more diverse than it was originally thought.
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Affiliation(s)
- Jitka Štáfková
- Department of Parasitology, Faculty of Science, Charles University in Prague, Czech Republic
| | - Jan Mach
- Department of Parasitology, Faculty of Science, Charles University in Prague, Czech Republic
| | - Marc Biran
- Centre de Résonance Magnétique des Systèmes Biologiques (RMSB), UMR5536 CNRS
| | - Zdeněk Verner
- Department of Parasitology, Faculty of Science, Charles University in Prague, Czech Republic
| | - Frédéric Bringaud
- Centre de Résonance Magnétique des Systèmes Biologiques (RMSB), UMR5536 CNRS.,Laboratoire de Microbiologie Fondamentale et Pathogénicité (MFP), UMR5234 CNRS, Université de Bordeaux, Bordeaux, France
| | - Jan Tachezy
- Department of Parasitology, Faculty of Science, Charles University in Prague, Czech Republic
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24
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Musunda B, Benítez D, Dirdjaja N, Comini MA, Krauth-Siegel RL. Glutaredoxin-deficiency confers bloodstream Trypanosoma brucei with improved thermotolerance. Mol Biochem Parasitol 2016; 204:93-105. [PMID: 26854591 DOI: 10.1016/j.molbiopara.2016.02.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Revised: 02/02/2016] [Accepted: 02/03/2016] [Indexed: 12/16/2022]
Abstract
As constituents of their unusual trypanothione-based thiol metabolism, African trypanosomes express two dithiol glutaredoxins (Grxs), a cytosolic Grx1 and a mitochondrial Grx2, with so far unknown biological functions. As revealed by gel shift assays, in the mammalian bloodstream form of Trypanosoma brucei, Grx1 is in the fully reduced state. Upon diamide treatment of the cells, Grx1 forms an active site disulfide bridge that is rapidly re-reduced after stress removal; Cys76, a conserved non-active site Cys remains in the thiol state. Deletion of both grx1 alleles does not result in any proliferation defect of neither the procyclic insect form nor the bloodstream form, even not under various stress conditions. In addition, the Grx1-deficient parasites are fully infectious in the mouse model. A functional compensation by Grx2 is unlikely as identical levels of Grx2 were found in wildtype and Grx1-deficient cells. In the classical hydroxyethyl disulfide assay, Grx1-deficient bloodstream cells display 50-60% of the activity of wildtype cells indicating that the cytosolic oxidoreductase accounts for a major part of the total deglutathionylation capacity of the parasite. Intriguingly, at elevated temperature, proliferation of the Grx1-deficient bloodstream parasites is significantly less affected compared to wildtype cells. When cultured for three days at 39°C, only 51% of the cells in the wildtype population retained normal morphology with single mitochondrial and nuclear DNA (1K1N), whereas 27% of the cells displayed ≥2K2N. In comparison, 64% of the Grx1-deficient cells kept the 1K1N phenotype and only 18% had ≥2K2N. The data suggest that Grx1 plays a role in the regulation of the thermotolerance of the parasites by (in)directly interfering with the progression of the cell cycle, a process that may comprise protein (de)glutathionylation step(s).
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Affiliation(s)
- Blessing Musunda
- Biochemie-Zentrum der Universität Heidelberg, Im Neuenheimer Feld 328, 69120 Heidelberg, Germany
| | - Diego Benítez
- Group Redox Biology of Trypanosomes, Institut Pasteur de Montevideo, Mataojo 2020, CP 11400 Montevideo, Uruguay
| | - Natalie Dirdjaja
- Biochemie-Zentrum der Universität Heidelberg, Im Neuenheimer Feld 328, 69120 Heidelberg, Germany
| | - Marcelo A Comini
- Group Redox Biology of Trypanosomes, Institut Pasteur de Montevideo, Mataojo 2020, CP 11400 Montevideo, Uruguay
| | - R Luise Krauth-Siegel
- Biochemie-Zentrum der Universität Heidelberg, Im Neuenheimer Feld 328, 69120 Heidelberg, Germany.
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Schaffroth C, Bogacz M, Dirdjaja N, Nißen A, Krauth-Siegel RL. The cytosolic or the mitochondrial glutathione peroxidase-type tryparedoxin peroxidase is sufficient to protect procyclic Trypanosoma brucei from iron-mediated mitochondrial damage and lysis. Mol Microbiol 2015; 99:172-87. [PMID: 26374473 DOI: 10.1111/mmi.13223] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/14/2015] [Indexed: 01/15/2023]
Abstract
African trypanosomes express three virtually identical glutathione peroxidase (Px)-type enzymes that occur in the cytosol (Px I and II) and mitochondrion (Px III) and detoxify fatty acid-derived hydroperoxides. Selective deletion of the genes revealed that procyclic Trypanosoma brucei lacking either the cytosolic or mitochondrial enzyme proliferate nearly as wild-type parasites, whereas the knockout of the complete genomic locus is lethal. Flow cytometry and immunofluorescence analyses revealed that the Px I-III-deficient parasites lose their mitochondrial membrane potential, which is followed by a loss of the lysosomal signal but not the glycosomal one. Mitochondrial damage and cell lysis are prevented by Trolox, ubiquinone derivatives and the iron chelator deferoxamine, whereas starch-deferoxamine is inefficient. In glucose-rich medium, cell death is attenuated suggesting that oxidants generated by the respiratory chain contribute to the lethal phenotype. Thus, the Px-type peroxidases protect procyclic cells from an iron-mediated oxidative membrane damage that originates at the mitochondrion. This contrasts with the situation in bloodstream cells, where the lysosome is the primarily affected organelle. Strikingly, either the cytosolic or the mitochondrial form of the peroxidases is required and sufficient to protect the mitochondrion and prevent cell lysis.
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Affiliation(s)
- Corinna Schaffroth
- Biochemie-Zentrum der Universität Heidelberg (BZH), Im Neuenheimer Feld 328, 69120, Heidelberg, Germany
| | - Marta Bogacz
- Biochemie-Zentrum der Universität Heidelberg (BZH), Im Neuenheimer Feld 328, 69120, Heidelberg, Germany
| | - Natalie Dirdjaja
- Biochemie-Zentrum der Universität Heidelberg (BZH), Im Neuenheimer Feld 328, 69120, Heidelberg, Germany
| | - Amrei Nißen
- Biochemie-Zentrum der Universität Heidelberg (BZH), Im Neuenheimer Feld 328, 69120, Heidelberg, Germany
| | - R Luise Krauth-Siegel
- Biochemie-Zentrum der Universität Heidelberg (BZH), Im Neuenheimer Feld 328, 69120, Heidelberg, Germany
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Carnes J, Anupama A, Balmer O, Jackson A, Lewis M, Brown R, Cestari I, Desquesnes M, Gendrin C, Hertz-Fowler C, Imamura H, Ivens A, Kořený L, Lai DH, MacLeod A, McDermott SM, Merritt C, Monnerat S, Moon W, Myler P, Phan I, Ramasamy G, Sivam D, Lun ZR, Lukeš J, Stuart K, Schnaufer A. Genome and phylogenetic analyses of Trypanosoma evansi reveal extensive similarity to T. brucei and multiple independent origins for dyskinetoplasty. PLoS Negl Trop Dis 2015; 9:e3404. [PMID: 25568942 PMCID: PMC4288722 DOI: 10.1371/journal.pntd.0003404] [Citation(s) in RCA: 103] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Accepted: 11/09/2014] [Indexed: 11/18/2022] Open
Abstract
Two key biological features distinguish Trypanosoma evansi from the T. brucei group: independence from the tsetse fly as obligatory vector, and independence from the need for functional mitochondrial DNA (kinetoplast or kDNA). In an effort to better understand the molecular causes and consequences of these differences, we sequenced the genome of an akinetoplastic T. evansi strain from China and compared it to the T. b. brucei reference strain. The annotated T. evansi genome shows extensive similarity to the reference, with 94.9% of the predicted T. b. brucei coding sequences (CDS) having an ortholog in T. evansi, and 94.6% of the non-repetitive orthologs having a nucleotide identity of 95% or greater. Interestingly, several procyclin-associated genes (PAGs) were disrupted or not found in this T. evansi strain, suggesting a selective loss of function in the absence of the insect life-cycle stage. Surprisingly, orthologous sequences were found in T. evansi for all 978 nuclear CDS predicted to represent the mitochondrial proteome in T. brucei, although a small number of these may have lost functionality. Consistent with previous results, the F1FO-ATP synthase γ subunit was found to have an A281 deletion, which is involved in generation of a mitochondrial membrane potential in the absence of kDNA. Candidates for CDS that are absent from the reference genome were identified in supplementary de novo assemblies of T. evansi reads. Phylogenetic analyses show that the sequenced strain belongs to a dominant group of clonal T. evansi strains with worldwide distribution that also includes isolates classified as T. equiperdum. At least three other types of T. evansi or T. equiperdum have emerged independently. Overall, the elucidation of the T. evansi genome sequence reveals extensive similarity of T. brucei and supports the contention that T. evansi should be classified as a subspecies of T. brucei.
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Affiliation(s)
- Jason Carnes
- Seattle Biomedical Research Institute, Seattle, United States of America
| | - Atashi Anupama
- Seattle Biomedical Research Institute, Seattle, United States of America
| | - Oliver Balmer
- Swiss Tropical and Public Health Institute, Basel, Switzerland
| | - Andrew Jackson
- Department of Infection Biology, Institute of Infection and Global Health, University of Liverpool, Liverpool, United Kingdom
| | - Michael Lewis
- Department of Pathogen Molecular Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Rob Brown
- Seattle Biomedical Research Institute, Seattle, United States of America
| | - Igor Cestari
- Seattle Biomedical Research Institute, Seattle, United States of America
| | - Marc Desquesnes
- CIRAD, UMR-InterTryp, Montpellier, France
- Faculty of Veterinary Medicine, Kasetsart University, Bangkok, Thailand
| | - Claire Gendrin
- Seattle Biomedical Research Institute, Seattle, United States of America
| | - Christiane Hertz-Fowler
- Centre for Genomic Research, Institute of Integrative Biology, University of Liverpool, Liverpool, United Kingdom
| | - Hideo Imamura
- Unit of Molecular Parasitology, Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
| | - Alasdair Ivens
- Centre of Immunity, Infection and Evolution, University of Edinburgh, Edinburgh, United Kingdom
| | - Luděk Kořený
- Biology Centre, Institute of Parasitology, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic
- Faculty of Sciences, University of South Bohemia, Centre, České Budějovice (Budweis), Czech Republic
| | - De-Hua Lai
- Biology Centre, Institute of Parasitology, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic
- Faculty of Sciences, University of South Bohemia, Centre, České Budějovice (Budweis), Czech Republic
- Center for Parasitic Organisms, State Key Laboratory of Biocontrol, School of Life Sciences, and Key Laboratory of Tropical Disease Control of Ministry of Education, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, People′s Republic of China
| | - Annette MacLeod
- Wellcome Trust Centre for Molecular Parasitology, Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | | | - Chris Merritt
- Seattle Biomedical Research Institute, Seattle, United States of America
| | - Severine Monnerat
- Seattle Biomedical Research Institute, Seattle, United States of America
| | - Wonjong Moon
- Seattle Biomedical Research Institute, Seattle, United States of America
| | - Peter Myler
- Seattle Biomedical Research Institute, Seattle, United States of America
| | - Isabelle Phan
- Seattle Biomedical Research Institute, Seattle, United States of America
| | - Gowthaman Ramasamy
- Seattle Biomedical Research Institute, Seattle, United States of America
| | - Dhileep Sivam
- Seattle Biomedical Research Institute, Seattle, United States of America
| | - Zhao-Rong Lun
- Center for Parasitic Organisms, State Key Laboratory of Biocontrol, School of Life Sciences, and Key Laboratory of Tropical Disease Control of Ministry of Education, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, People′s Republic of China
- * E-mail: (ZRL); (JL); (KS); (AS)
| | - Julius Lukeš
- Biology Centre, Institute of Parasitology, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic
- Faculty of Sciences, University of South Bohemia, Centre, České Budějovice (Budweis), Czech Republic
- Canadian Institute for Advanced Research, Toronto, Canada
- * E-mail: (ZRL); (JL); (KS); (AS)
| | - Ken Stuart
- Seattle Biomedical Research Institute, Seattle, United States of America
- Department of Global Health, University of Washington, Seattle, United States of America
- * E-mail: (ZRL); (JL); (KS); (AS)
| | - Achim Schnaufer
- Centre of Immunity, Infection and Evolution, University of Edinburgh, Edinburgh, United Kingdom
- Institute of Immunology & Infection Research, University of Edinburgh, Edinburgh, United Kingdom
- * E-mail: (ZRL); (JL); (KS); (AS)
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27
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Huang G, Vercesi AE, Docampo R. Essential regulation of cell bioenergetics in Trypanosoma brucei by the mitochondrial calcium uniporter. Nat Commun 2014; 4:2865. [PMID: 24305511 PMCID: PMC3868461 DOI: 10.1038/ncomms3865] [Citation(s) in RCA: 102] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Accepted: 11/04/2013] [Indexed: 01/07/2023] Open
Abstract
Mechanisms of regulation of mitochondrial metabolism in trypanosomes are not completely understood. Here we present evidence that the Trypanosoma brucei mitochondrial calcium uniporter (TbMCU) is essential for regulation of mitochondrial bioenergetics, autophagy, and cell death, even in the bloodstream forms that are devoid of a functional respiratory chain and oxidative phosphorylation. Localization studies reveal its co-localization with MitoTracker staining. TbMCU overexpression increases mitochondrial Ca2+ accumulation in intact and permeabilized trypanosomes, generates excessive mitochondrial reactive oxygen species (ROS), and sensitizes them to apoptotic stimuli. Ablation of TbMCU in RNAi or conditional knockout trypanosomes reduces mitochondrial Ca2+ uptake without affecting their membrane potential, increases the AMP/ATP ratio, stimulates autophagosome formation, and produces marked defects in growth in vitro and infectivity in mice, revealing its essentiality in these parasites. The requirement of TbMCU for proline and pyruvate metabolism in procyclic and bloodstream forms, respectively, reveals its role in regulation of mitochondrial bioenergetics.
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Affiliation(s)
- Guozhong Huang
- Center for Tropical and Emerging Global Diseases and Department of Cellular Biology, University of Georgia, Athens, Georgia 30602, USA
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28
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Abstract
The potential of flavoproteins as targets of pharmacological treatments is immense. In this review we present an overview of the current research progress on medical interventions based on flavoproteins with a special emphasis on cancer, infectious diseases, and neurological disorders.
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Affiliation(s)
- Esther Jortzik
- Interdisciplinary Research Center, Justus Liebig University, Giessen, Germany
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29
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Mazet M, Morand P, Biran M, Bouyssou G, Courtois P, Daulouède S, Millerioux Y, Franconi JM, Vincendeau P, Moreau P, Bringaud F. Revisiting the central metabolism of the bloodstream forms of Trypanosoma brucei: production of acetate in the mitochondrion is essential for parasite viability. PLoS Negl Trop Dis 2013; 7:e2587. [PMID: 24367711 PMCID: PMC3868518 DOI: 10.1371/journal.pntd.0002587] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Accepted: 10/30/2013] [Indexed: 11/24/2022] Open
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. 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.
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Affiliation(s)
- Muriel Mazet
- Centre de Résonance Magnétique des Systèmes Biologiques (RMSB), UMR5536, Université Bordeaux Segalen, CNRS, Bordeaux, France
| | - Pauline Morand
- Centre de Résonance Magnétique des Systèmes Biologiques (RMSB), UMR5536, Université Bordeaux Segalen, CNRS, Bordeaux, France
| | - Marc Biran
- Centre de Résonance Magnétique des Systèmes Biologiques (RMSB), UMR5536, Université Bordeaux Segalen, CNRS, Bordeaux, France
| | - Guillaume Bouyssou
- Laboratoire de Biogenèse Membranaire, UMR5200 Université Bordeaux Segalen, CNRS, Bâtiment A3, INRA Bordeaux Aquitaine, Villenave d'Ornon, France
| | - Pierrette Courtois
- Laboratoire de Parasitologie, UMR177 IRD CIRAD, Université Bordeaux Segalen, BP 43, Bordeaux, France
| | - Sylvie Daulouède
- Laboratoire de Parasitologie, UMR177 IRD CIRAD, Université Bordeaux Segalen, BP 43, Bordeaux, France
| | - Yoann Millerioux
- Centre de Résonance Magnétique des Systèmes Biologiques (RMSB), UMR5536, Université Bordeaux Segalen, CNRS, Bordeaux, France
| | - Jean-Michel Franconi
- Centre de Résonance Magnétique des Systèmes Biologiques (RMSB), UMR5536, Université Bordeaux Segalen, CNRS, Bordeaux, France
| | - Philippe Vincendeau
- Laboratoire de Parasitologie, UMR177 IRD CIRAD, Université Bordeaux Segalen, BP 43, Bordeaux, France
| | - Patrick Moreau
- Laboratoire de Biogenèse Membranaire, UMR5200 Université Bordeaux Segalen, CNRS, Bâtiment A3, INRA Bordeaux Aquitaine, Villenave d'Ornon, France
| | - Frédéric Bringaud
- Centre de Résonance Magnétique des Systèmes Biologiques (RMSB), UMR5536, Université Bordeaux Segalen, CNRS, Bordeaux, France
- * E-mail: .
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30
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Manta B, Pavan C, Sturlese M, Medeiros A, Crispo M, Berndt C, Krauth-Siegel RL, Bellanda M, Comini MA. Iron-sulfur cluster binding by mitochondrial monothiol glutaredoxin-1 of Trypanosoma brucei: molecular basis of iron-sulfur cluster coordination and relevance for parasite infectivity. Antioxid Redox Signal 2013; 19:665-82. [PMID: 23259530 PMCID: PMC3739951 DOI: 10.1089/ars.2012.4859] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
AIMS Monothiol glutaredoxins (1-C-Grxs) are small proteins linked to the cellular iron and redox metabolism. Trypanosoma brucei brucei, model organism for human African trypanosomiasis, expresses three 1-C-Grxs. 1-C-Grx1 is a highly abundant mitochondrial protein capable to bind an iron-sulfur cluster (ISC) in vitro using glutathione (GSH) as cofactor. We here report on the functional and structural analysis of 1-C-Grx1 in relation to its ISC-binding properties. RESULTS An N-terminal extension unique to 1-C-Grx1 from trypanosomatids affects the oligomeric structure and the ISC-binding capacity of the protein. The active-site Cys104 is essential for ISC binding, and the parasite-specific glutathionylspermidine and trypanothione can replace GSH as the ligands of the ISC. Interestingly, trypanothione forms stable protein-free ISC species that in vitro are incorporated into the dithiol T. brucei 2-C-Grx1, but not 1-C-Grx1. Overexpression of the C104S mutant of 1-C-Grx1 impairs disease progression in a mouse model. The structure of the Grx-domain of 1-C-Grx1 was solved by nuclear magnetic resonance spectroscopy. Despite the fact that several residues--which in other 1-C-Grxs are involved in the noncovalent binding of GSH--are conserved, different physicochemical approaches did not reveal any specific interaction between 1-C-Grx1 and free thiol ligands. INNOVATION Parasite Grxs are able to coordinate an ISC formed with trypanothione, suggesting a new mechanism of ISC binding and a novel function for the parasite-specific dithiol. The first 3D structure and in vivo relevance of a 1-C-Grx from a pathogenic protozoan are reported. CONCLUSION T. brucei 1-C-Grx1 is indispensable for mammalian parasitism and utilizes a new mechanism for ISC binding.
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Affiliation(s)
- Bruno Manta
- Laboratory Redox Biology of Trypanosomes, Institut Pasteur de Montevideo, Montevideo, Uruguay
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31
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Single point mutations in ATP synthase compensate for mitochondrial genome loss in trypanosomes. Proc Natl Acad Sci U S A 2013; 110:14741-6. [PMID: 23959897 DOI: 10.1073/pnas.1305404110] [Citation(s) in RCA: 103] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Viability of the tsetse fly-transmitted African trypanosome Trypanosoma brucei depends on maintenance and expression of its kinetoplast (kDNA), the mitochondrial genome of this parasite and a putative target for veterinary and human antitrypanosomatid drugs. However, the closely related animal pathogens T. evansi and T. equiperdum are transmitted independently of tsetse flies and survive without a functional kinetoplast for reasons that have remained unclear. Here, we provide definitive evidence that single amino acid changes in the nuclearly encoded F1FO-ATPase subunit γ can compensate for complete physical loss of kDNA in these parasites. Our results provide insight into the molecular mechanism of compensation for kDNA loss by showing FO-independent generation of the mitochondrial membrane potential with increased dependence on the ADP/ATP carrier. Our findings also suggest that, in the pathogenic bloodstream stage of T. brucei, the huge and energetically demanding apparatus required for kDNA maintenance and expression serves the production of a single F1FO-ATPase subunit. These results have important implications for drug discovery and our understanding of the evolution of these parasites.
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Hashimi H, McDonald L, Stríbrná E, Lukeš J. Trypanosome Letm1 protein is essential for mitochondrial potassium homeostasis. J Biol Chem 2013; 288:26914-25. [PMID: 23893410 DOI: 10.1074/jbc.m113.495119] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Letm1 is a conserved protein in eukaryotes bearing energized mitochondria. Hemizygous deletion of its gene has been implicated in symptoms of the human disease Wolf-Hirschhorn syndrome. Studies almost exclusively performed in opisthokonts have attributed several roles to Letm1, including maintaining mitochondrial morphology, mediating either calcium or potassium/proton antiport, and facilitating mitochondrial translation. We address the ancestral function of Letm1 in the highly diverged protist and significant pathogen, Trypanosoma brucei. We demonstrate that Letm1 is involved in maintaining mitochondrial volume via potassium/proton exchange across the inner membrane. This role is essential in the vector-dwelling procyclic and mammal-infecting bloodstream stages as well as in Trypanosoma brucei evansi, a form of the latter stage lacking an organellar genome. In the pathogenic bloodstream stage, the mitochondrion consumes ATP to maintain an energized state, whereas that of T. brucei evansi also lacks a conventional proton-driven membrane potential. Thus, Letm1 performs its function in different physiological states, suggesting that ion homeostasis is among the few characterized essential pathways of the mitochondrion at this T. brucei life stage. Interestingly, Letm1 depletion in the procyclic stage can be complemented by exogenous expression of its human counterpart, highlighting the conservation of protein function between highly divergent species. Furthermore, although mitochondrial translation is affected upon Letm1 ablation, it is an indirect consequence of K(+) accumulation in the matrix.
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Affiliation(s)
- Hassan Hashimi
- From the Institute of Parasitology, Biology Centre, Czech Academy of Sciences and
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Dual functions of α-ketoglutarate dehydrogenase E2 in the Krebs cycle and mitochondrial DNA inheritance in Trypanosoma brucei. EUKARYOTIC CELL 2012; 12:78-90. [PMID: 23125353 DOI: 10.1128/ec.00269-12] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The dihydrolipoyl succinyltransferase (E2) of the multisubunit α-ketoglutarate dehydrogenase complex (α-KD) is an essential Krebs cycle enzyme commonly found in the matrices of mitochondria. African trypanosomes developmentally regulate mitochondrial carbohydrate metabolism and lack a functional Krebs cycle in the bloodstream of mammals. We found that despite the absence of a functional α-KD, bloodstream form (BF) trypanosomes express α-KDE2, which localized to the mitochondrial matrix and inner membrane. Furthermore, α-KDE2 fractionated with the mitochondrial genome, the kinetoplast DNA (kDNA), in a complex with the flagellum. A role for α-KDE2 in kDNA maintenance was revealed in α-KDE2 RNA interference (RNAi) knockdowns. Following RNAi induction, bloodstream trypanosomes showed pronounced growth reduction and often failed to equally distribute kDNA to daughter cells, resulting in accumulation of cells devoid of kDNA (dyskinetoplastic) or containing two kinetoplasts. Dyskinetoplastic trypanosomes lacked mitochondrial membrane potential and contained mitochondria of substantially reduced volume. These results indicate that α-KDE2 is bifunctional, both as a metabolic enzyme and as a mitochondrial inheritance factor necessary for the distribution of kDNA networks to daughter cells at cytokinesis.
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34
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Enigmatic presence of mitochondrial complex I in Trypanosoma brucei bloodstream forms. EUKARYOTIC CELL 2011; 11:183-93. [PMID: 22158713 DOI: 10.1128/ec.05282-11] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The presence of mitochondrial respiratory complex I in the pathogenic bloodstream stages of Trypanosoma brucei has been vigorously debated: increased expression of mitochondrially encoded functional complex I mRNAs is countered by low levels of enzymatic activity that show marginal inhibition by the specific inhibitor rotenone. We now show that epitope-tagged versions of multiple complex I subunits assemble into α and β subcomplexes in the bloodstream stage and that these subcomplexes require the mitochondrial genome for their assembly. Despite the presence of these large (740- and 855-kDa) multisubunit complexes, the electron transport activity of complex I is not essential under experimental conditions since null mutants of two core genes (NUBM and NUKM) showed no growth defect in vitro or in mouse infection. Furthermore, the null mutants showed no decrease in NADH:ubiquinone oxidoreductase activity, suggesting that the observed activity is not contributed by complex I. This work conclusively shows that despite the synthesis and assembly of subunit proteins, the enzymatic function of the largest respiratory complex is neither significant nor important in the bloodstream stage. This situation appears to be in striking contrast to that for the other respiratory complexes in this parasite, where physical presence in a life-cycle stage always indicates functional significance.
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