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Anuntasomboon P, Siripattanapipong S, Unajak S, Choowongkomon K, Burchmore R, Leelayoova S, Mungthin M, E-Kobon T. Identification of a unique conserved region from a kinetoplastid genome of Leishmania orientalis (formerly named Leishmania siamensis) strain PCM2 in Thailand. Sci Rep 2023; 13:19644. [PMID: 37950023 PMCID: PMC10638283 DOI: 10.1038/s41598-023-46638-3] [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: 02/27/2023] [Accepted: 11/03/2023] [Indexed: 11/12/2023] Open
Abstract
Mitochondrial DNAs (mtDNAs) appear in almost all eukaryotic species and are useful molecular markers for phylogenetic studies and species identification. Kinetoplast DNAs (kDNAs) are structurally complex circular mtDNA networks in kinetoplastids, divided into maxicircles and minicircles. Despite several kDNAs of many Leishmania species being examined, the kDNAs of the new species, Leishmania orientalis (formerly named Leishmania siamensis) strain PCM2, have not been explored. This study aimed to investigate the maxicircle and minicircle DNAs of L. orientalis strain PCM2 using hybrid genome sequencing technologies and bioinformatic analyses. The kDNA sequences were isolated and assembled using the SPAdes hybrid assembler from the Illumina short-read and PacBio long-read data. Circular contigs of the maxicircle and minicircle DNAs were reconstructed and confirmed by BLASTn and rKOMICs programs. The kDNA genome was annotated by BLASTn before the genome comparison and phylogenetic analysis by progressiveMauve, MAFFT, and MEGA programs. The maxicircle of L. orientalis strain PCM2 (18,215 bp) showed 99.92% similarity and gene arrangement to Leishmania enriettii strain LEM3045 maxicircle with variation in the 12s rRNA gene and divergent region. Phylogenetics of the whole sequence, coding regions, divergent regions, and 12s rRNA gene also confirmed this relationship and subgenera separation. The identified 105 classes of minicircles (402-1177 bp) were clustered monophyletically and related to the Leishmania donovani minicircles. The kinetoplast maxicircle and minicircle DNAs of L. orientalis strain PCM2 contained a unique conserved region potentially useful for specific diagnosis of L. orientalis and further exploration of this parasite population genetics in Thailand and related regions.
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Affiliation(s)
- Pornchai Anuntasomboon
- Department of Genetics, Faculty of Science, Kasetsart University, Bangkok, Thailand
- Omics Center for Agriculture, Bioresources, Food, and Health, Kasetsart University (OmiKU), Bangkok, Thailand
| | | | - Sasimanas Unajak
- Department of Biochemistry, Faculty of Science, Kasetsart University, Bangkok, Thailand
| | | | - Richard Burchmore
- Glasgow Polyomics, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Saovanee Leelayoova
- Department of Parasitology, Phramongkutklao College of Medicine, Bangkok, Thailand
| | - Mathirut Mungthin
- Department of Parasitology, Phramongkutklao College of Medicine, Bangkok, Thailand
| | - Teerasak E-Kobon
- Department of Genetics, Faculty of Science, Kasetsart University, Bangkok, Thailand.
- Omics Center for Agriculture, Bioresources, Food, and Health, Kasetsart University (OmiKU), Bangkok, Thailand.
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Halliday C, Dean S, Sunter JD, Wheeler RJ. Subcellular protein localisation of Trypanosoma brucei bloodstream form-upregulated proteins maps stage-specific adaptations. Wellcome Open Res 2023; 8:46. [PMID: 37251657 PMCID: PMC10209625 DOI: 10.12688/wellcomeopenres.18586.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/21/2023] [Indexed: 05/31/2023] Open
Abstract
Background: Genome-wide subcellular protein localisation in Trypanosoma brucei, through our TrypTag project, has comprehensively dissected the molecular organisation of this important pathogen. Powerful as this resource is , T. brucei has multiple developmental forms and we previously only analysed the procyclic form. This is an insect life cycle stage, leaving the mammalian bloodstream form unanalysed. The expectation is that between life stages protein localisation would not change dramatically (completely unchanged or shifting to analogous stage-specific structures). However, this has not been specifically tested. Similarly, which organelles tend to contain proteins with stage-specific expression can be predicted from known stage specific adaptations but has not been comprehensively tested. Methods: We used endogenous tagging with mNG to determine the sub-cellular localisation of the majority of proteins encoded by transcripts significantly upregulated in the bloodstream form, and performed comparison to the existing localisation data in procyclic forms. Results: We have confirmed the localisation of known stage-specific proteins and identified the localisation of novel stage-specific proteins. This gave a map of which organelles tend to contain stage specific proteins: the mitochondrion for the procyclic form, and the endoplasmic reticulum, endocytic system and cell surface in the bloodstream form. Conclusions: This represents the first genome-wide map of life cycle stage-specific adaptation of organelle molecular machinery in T. brucei.
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Affiliation(s)
- Clare Halliday
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Samuel Dean
- Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry, UK
| | - Jack Daniel Sunter
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, UK
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3
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Andrade-Alviárez D, Bonive-Boscan AD, Cáceres AJ, Quiñones W, Gualdrón-López M, Ginger ML, Michels PAM. Delineating transitions during the evolution of specialised peroxisomes: Glycosome formation in kinetoplastid and diplonemid protists. Front Cell Dev Biol 2022; 10:979269. [PMID: 36172271 PMCID: PMC9512073 DOI: 10.3389/fcell.2022.979269] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Accepted: 08/17/2022] [Indexed: 12/01/2022] Open
Abstract
One peculiarity of protists belonging to classes Kinetoplastea and Diplonemea within the phylum Euglenozoa is compartmentalisation of most glycolytic enzymes within peroxisomes that are hence called glycosomes. This pathway is not sequestered in peroxisomes of the third Euglenozoan class, Euglenida. Previous analysis of well-studied kinetoplastids, the ‘TriTryps’ parasites Trypanosoma brucei, Trypanosoma cruzi and Leishmania spp., identified within glycosomes other metabolic processes usually not present in peroxisomes. In addition, trypanosomatid peroxins, i.e. proteins involved in biogenesis of these organelles, are divergent from human and yeast orthologues. In recent years, genomes, transcriptomes and proteomes for a variety of euglenozoans have become available. Here, we track the possible evolution of glycosomes by querying these databases, as well as the genome of Naegleria gruberi, a non-euglenozoan, which belongs to the same protist supergroup Discoba. We searched for orthologues of TriTryps proteins involved in glycosomal metabolism and biogenesis. Predicted cellular location(s) of each metabolic enzyme identified was inferred from presence or absence of peroxisomal-targeting signals. Combined with a survey of relevant literature, we refine extensively our previously postulated hypothesis about glycosome evolution. The data agree glycolysis was compartmentalised in a common ancestor of the kinetoplastids and diplonemids, yet additionally indicates most other processes found in glycosomes of extant trypanosomatids, but not in peroxisomes of other eukaryotes were either sequestered in this ancestor or shortly after separation of the two lineages. In contrast, peroxin divergence is evident in all euglenozoans. Following their gain of pathway complexity, subsequent evolution of peroxisome/glycosome function is complex. We hypothesize compartmentalisation in glycosomes of glycolytic enzymes, their cofactors and subsequently other metabolic enzymes provided selective advantage to kinetoplastids and diplonemids during their evolution in changing marine environments. We contend two specific properties derived from the ancestral peroxisomes were key: existence of nonselective pores for small solutes and the possibility of high turnover by pexophagy. Critically, such pores and pexophagy are characterised in extant trypanosomatids. Increasing amenability of free-living kinetoplastids and recently isolated diplonemids to experimental study means our hypothesis and interpretation of bioinformatic data are suited to experimental interrogation.
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Affiliation(s)
- Diego Andrade-Alviárez
- Laboratorio de Enzimología de Parásitos, Departamento de Biología, Facultad de Ciencias, Universidad de Los Andes, Mérida, Venezuela
| | - Alejandro D. Bonive-Boscan
- Laboratorio de Enzimología de Parásitos, Departamento de Biología, Facultad de Ciencias, Universidad de Los Andes, Mérida, Venezuela
| | - Ana J. Cáceres
- Laboratorio de Enzimología de Parásitos, Departamento de Biología, Facultad de Ciencias, Universidad de Los Andes, Mérida, Venezuela
| | - Wilfredo Quiñones
- Laboratorio de Enzimología de Parásitos, Departamento de Biología, Facultad de Ciencias, Universidad de Los Andes, Mérida, Venezuela
| | | | - Michael L. Ginger
- School of Applied Sciences, University of Huddersfield, Huddersfield, United Kingdom
| | - Paul A. M. Michels
- Centre for Immunity, Infection and Evolution and Centre for Translational and Chemical Biology, School of Biological Sciences, The University of Edinburgh, Edinburgh, United Kingdom
- *Correspondence: Paul A. M. Michels,
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Mutuku CN, Bateta R, Rono MK, Njunge JM, Awuoche EO, Ndung'u K, Mang'era CM, Akoth MO, Adung'a VO, Ondigo BN, Mireji PO. Physiological and proteomic profiles of Trypanosoma brucei rhodesiense parasite isolated from suramin responsive and non-responsive HAT patients in Busoga, Uganda. Int J Parasitol Drugs Drug Resist 2021; 15:57-67. [PMID: 33588295 PMCID: PMC7895675 DOI: 10.1016/j.ijpddr.2021.02.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 02/02/2021] [Accepted: 02/02/2021] [Indexed: 11/17/2022]
Abstract
Human African Trypanosomiasis (HAT) is a disease of major economic importance in Sub-Saharan Africa. The HAT is caused by Trypanosoma brucei rhodesiense (Tbr) parasite in eastern and southern Africa, with suramin as drug of choice for treatment of early stage of the disease. Suramin treatment failures has been observed among HAT patients in Tbr foci in Uganda. In this study, we assessed Tbr parasite strains isolated from HAT patients responsive (Tbr EATRO-232) and non-responsive (Tbr EATRO-734) to suramin treatment in Busoga, Uganda for 1) putative role of suramin resistance in the treatment failure 2) correlation of suramin resistance with Tbr pathogenicity and 3) proteomic pathways underpinning the potential suramin resistance phenotype in vivo. We first assessed suramin response in each isolate by infecting male Swiss white mice followed by treatment using a series of suramin doses. We then assessed relative pathogenicity of the two Tbr isolates by assessing changes pathogenicity indices (prepatent period, survival and mortality). We finally isolated proteins from mice infected by the isolates, and assessed their proteomic profiles using mass spectrometry. We established putative resistance to 2.5 mg/kg suramin in the parasite Tbr EATRO-734. We established that Tbr EATRO-734 proliferated slower and has significantly enriched pathways associated with detoxification and metabolism of energy and drugs relative to Tbr EATRO-232. The Tbr EATRO-734 also has more abundantly expressed mitochondrion proteins and enzymes than Tbr EATRO-232. The suramin treatment failure may be linked to the relatively higher resistance to suramin in Tbr EATRO-734 than Tbr EATRO-232, among other host and parasite specific factors. However, the Tbr EATRO-734 appears to be less pathogenic than Tbr EATRO-232, as evidenced by its lower rate of parasitaemia. The Tbr EATRO-734 putatively surmount suramin challenges through induction of energy metabolism pathways. These cellular and molecular processes may be involved in suramin resistance in Tbr.
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Affiliation(s)
- Catherine N Mutuku
- Biotechnology Research Institute, Kenya Agricultural and Livestock Research Organization, P.O. Box 362, Kikuyu, Kenya; Department of Biochemistry and Molecular Biology, Egerton University, P.O. Box 536, Njoro, Kenya
| | - Rosemary Bateta
- Biotechnology Research Institute, Kenya Agricultural and Livestock Research Organization, P.O. Box 362, Kikuyu, Kenya.
| | - Martin K Rono
- Centre for Geographic Medicine Research - Coast, Kenya Medical Research Institute, PO Box 230-80108 Kilifi, Kenya
| | - James M Njunge
- Centre for Geographic Medicine Research - Coast, Kenya Medical Research Institute, PO Box 230-80108 Kilifi, Kenya
| | - Erick O Awuoche
- Department of Biological Sciences, School of Pure and Applied Science, Meru University of Science and Technology, Meru, Kenya
| | - Kariuki Ndung'u
- Biotechnology Research Institute, Kenya Agricultural and Livestock Research Organization, P.O. Box 362, Kikuyu, Kenya
| | - Clarence M Mang'era
- Department of Biochemistry and Molecular Biology, Egerton University, P.O. Box 536, Njoro, Kenya
| | - Modesta O Akoth
- Biotechnology Research Institute, Kenya Agricultural and Livestock Research Organization, P.O. Box 362, Kikuyu, Kenya; Department of Biochemistry and Molecular Biology, Egerton University, P.O. Box 536, Njoro, Kenya
| | - Vincent O Adung'a
- Department of Biochemistry and Molecular Biology, Egerton University, P.O. Box 536, Njoro, Kenya
| | - Bartholomew N Ondigo
- Department of Biochemistry and Molecular Biology, Egerton University, P.O. Box 536, Njoro, Kenya
| | - Paul O Mireji
- Biotechnology Research Institute, Kenya Agricultural and Livestock Research Organization, P.O. Box 362, Kikuyu, Kenya; Centre for Geographic Medicine Research - Coast, Kenya Medical Research Institute, PO Box 230-80108 Kilifi, Kenya.
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Alhasawi AA, Thomas SC, Tharmalingam S, Legendre F, Appanna VD. Isocitrate Lyase and Succinate Semialdehyde Dehydrogenase Mediate the Synthesis of α-Ketoglutarate in Pseudomonas fluorescens. Front Microbiol 2019; 10:1929. [PMID: 31507554 PMCID: PMC6716453 DOI: 10.3389/fmicb.2019.01929] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Accepted: 08/05/2019] [Indexed: 01/04/2023] Open
Abstract
Glycerol is an important by-product of the biodiesel industry and its transformation into value-added products like keto acids is being actively pursued in order to improve the efficacy of this renewable energy sector. Here, we report that the enhanced production of α-ketoglutarate (KG) effected by Pseudomonas fluorescens in a mineral medium supplemented with manganese (Mn) is propelled by the increased activities of succinate semialdehyde dehydrogenase (SSADH), γ-aminobutyric acid aminotransaminase (GABAT), and isocitrate lyase (ICL). The latter generates glyoxylate and succinate two key metabolites involved in this process. Fumarate reductase (FRD) also aids in augmenting the pool of succinate, a precursor of succinate semialdehyde (SSA). The latter is then carboxylated to KG with the assistance of α-ketoglutarate decarboxylase (KDC). These enzymes work in tandem to ensure copious secretion of the keto acid. When incubated with glycerol in the presence of bicarbonate (HCO3−), cell-free extracts readily produce KG with a metabolite fingerprint attributed to glutamate, γ-aminobutyric acid (GABA), succinate and succinate semialdehyde. Further targeted metabolomic and functional proteomic studies with high-performance liquid chromatography (HPLC), nuclear magnetic resonance (NMR) and gel electrophoresis techniques provided molecular insights into this KG-generating machinery. Real-time quantitative polymerase chain reaction (RT-qPCR) analyses revealed the transcripts responsible for ICL and SSADH were elevated in the Mn-supplemented cultures. This hitherto unreported metabolic network where ICL and SSADH orchestrate the enhanced production of KG from glycerol, provides an elegant means of converting an industrial waste into a keto acid with wide-ranging application in the medical, cosmetic, and chemical sectors.
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Affiliation(s)
- Azhar A Alhasawi
- Department of Chemistry and Biochemistry, Laurentian University, Sudbury, ON, Canada
| | - Sean C Thomas
- Department of Chemistry and Biochemistry, Laurentian University, Sudbury, ON, Canada
| | - Sujeethar Tharmalingam
- Department of Chemistry and Biochemistry, Laurentian University, Sudbury, ON, Canada.,Department of Biology, Laurentian University, Sudbury, ON, Canada.,Biomolecular Sciences Program, Laurentian University, Sudbury, ON, Canada.,Northern Ontario School of Medicine, Laurentian University, Sudbury, ON, Canada
| | - Felix Legendre
- Department of Chemistry and Biochemistry, Laurentian University, Sudbury, ON, Canada
| | - Vasu D Appanna
- Department of Chemistry and Biochemistry, Laurentian University, Sudbury, ON, Canada
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Kovářová J, Nagar R, Faria J, Ferguson MAJ, Barrett MP, Horn D. Gluconeogenesis using glycerol as a substrate in bloodstream-form Trypanosoma brucei. PLoS Pathog 2018; 14:e1007475. [PMID: 30589893 PMCID: PMC6307712 DOI: 10.1371/journal.ppat.1007475] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Accepted: 11/19/2018] [Indexed: 12/20/2022] Open
Abstract
Bloodstream form African trypanosomes are thought to rely exclusively upon glycolysis, using glucose as a substrate, for ATP production. Indeed, the pathway has long been considered a potential therapeutic target to tackle the devastating and neglected tropical diseases caused by these parasites. However, plasma membrane glucose and glycerol transporters are both expressed by trypanosomes and these parasites can infiltrate tissues that contain glycerol. Here, we show that bloodstream form trypanosomes can use glycerol for gluconeogenesis and for ATP production, particularly when deprived of glucose following hexose transporter depletion. We demonstrate that Trypanosoma brucei hexose transporters 1 and 2 (THT1 and THT2) are localized to the plasma membrane and that knockdown of THT1 expression leads to a growth defect that is more severe when THT2 is also knocked down. These data are consistent with THT1 and THT2 being the primary routes of glucose supply for the production of ATP by glycolysis. However, supplementation of the growth medium with glycerol substantially rescued the growth defect caused by THT1 and THT2 knockdown. Metabolomic analyses with heavy-isotope labelled glycerol demonstrated that trypanosomes take up glycerol and use it to synthesize intermediates of gluconeogenesis, including fructose 1,6-bisphosphate and hexose 6-phosphates, which feed the pentose phosphate pathway and variant surface glycoprotein biosynthesis. We used Cas9-mediated gene knockout to demonstrate a gluconeogenesis-specific, but fructose-1,6-bisphosphatase (Tb927.9.8720)-independent activity, converting fructose 1,6-bisphosphate into fructose 6-phosphate. In addition, we observed increased flux through the tricarboxylic acid cycle and the succinate shunt. Thus, contrary to prior thinking, gluconeogenesis can operate in bloodstream form T. brucei. This pathway, using glycerol as a physiological substrate, may be required in mammalian host tissues.
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Affiliation(s)
- Julie Kovářová
- The Wellcome Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dow Street, Dundee, United Kingdom
| | - Rupa Nagar
- The Wellcome Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dow Street, Dundee, United Kingdom
| | - Joana Faria
- The Wellcome Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dow Street, Dundee, United Kingdom
| | - Michael A. J. Ferguson
- The Wellcome Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dow Street, Dundee, United Kingdom
| | - Michael P. Barrett
- The Wellcome Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
- Glasgow Polyomics, University of Glasgow, Glasgow, United Kingdom
| | - David Horn
- The Wellcome Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dow Street, Dundee, United Kingdom
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Zíková A, Verner Z, Nenarokova A, Michels PAM, Lukeš J. A paradigm shift: The mitoproteomes of procyclic and bloodstream Trypanosoma brucei are comparably complex. PLoS Pathog 2017; 13:e1006679. [PMID: 29267392 PMCID: PMC5739487 DOI: 10.1371/journal.ppat.1006679] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Affiliation(s)
- Alena Zíková
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic
- Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
- * E-mail:
| | - Zdeněk Verner
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic
- Faculty of Sciences, Charles University, Prague, Czech Republic
| | - Anna Nenarokova
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic
- Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
| | - Paul A. M. Michels
- Centre for Immunity, Infection and Evolution, The University of Edinburgh, Edinburgh, United Kingdom
| | - Julius Lukeš
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic
- Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
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Kirby LE, Koslowsky D. Mitochondrial dual-coding genes in Trypanosoma brucei. PLoS Negl Trop Dis 2017; 11:e0005989. [PMID: 28991908 PMCID: PMC5650466 DOI: 10.1371/journal.pntd.0005989] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Revised: 10/20/2017] [Accepted: 09/23/2017] [Indexed: 12/31/2022] Open
Abstract
Trypanosoma brucei is transmitted between mammalian hosts by the tsetse fly. In the mammal, they are exclusively extracellular, continuously replicating within the bloodstream. During this stage, the mitochondrion lacks a functional electron transport chain (ETC). Successful transition to the fly, requires activation of the ETC and ATP synthesis via oxidative phosphorylation. This life cycle leads to a major problem: in the bloodstream, the mitochondrial genes are not under selection and are subject to genetic drift that endangers their integrity. Exacerbating this, T. brucei undergoes repeated population bottlenecks as they evade the host immune system that would create additional forces of genetic drift. These parasites possess several unique genetic features, including RNA editing of mitochondrial transcripts. RNA editing creates open reading frames by the guided insertion and deletion of U-residues within the mRNA. A major question in the field has been why this metabolically expensive system of RNA editing would evolve and persist. Here, we show that many of the edited mRNAs can alter the choice of start codon and the open reading frame by alternative editing of the 5’ end. Analyses of mutational bias indicate that six of the mitochondrial genes may be dual-coding and that RNA editing allows access to both reading frames. We hypothesize that dual-coding genes can protect genetic information by essentially hiding a non-selected gene within one that remains under selection. Thus, the complex RNA editing system found in the mitochondria of trypanosomes provides a unique molecular strategy to combat genetic drift in non-selective conditions. In African trypanosomes, many of the mitochondrial mRNAs require extensive RNA editing before they can be translated. During this process, each edited transcript can undergo hundreds of cleavage/ligation events as U-residues are inserted or deleted to generate a translatable open reading frame. A major paradox has been why this incredibly metabolically expensive process would evolve and persist. In this work, we show that many of the mitochondrial genes in trypanosomes are dual-coding, utilizing different reading frames to potentially produce two very different proteins. Access to both reading frames is made possible by alternative editing of the 5’ end of the transcript. We hypothesize that dual-coding genes may work to protect the mitochondrial genes from mutations during growth in the mammalian host, when many of the mitochondrial genes are not being used. Thus, the complex RNA editing system may be maintained because it provides a unique molecular strategy to combat genetic drift.
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Affiliation(s)
- Laura E. Kirby
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, United States of America
| | - Donna Koslowsky
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, United States of America
- * E-mail:
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Szempruch AJ, Sykes SE, Kieft R, Dennison L, Becker AC, Gartrell A, Martin WJ, Nakayasu ES, Almeida IC, Hajduk SL, Harrington JM. Extracellular Vesicles from Trypanosoma brucei Mediate Virulence Factor Transfer and Cause Host Anemia. Cell 2016; 164:246-257. [PMID: 26771494 DOI: 10.1016/j.cell.2015.11.051] [Citation(s) in RCA: 189] [Impact Index Per Article: 23.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Revised: 10/02/2015] [Accepted: 11/16/2015] [Indexed: 01/19/2023]
Abstract
Intercellular communication between parasites and with host cells provides mechanisms for parasite development, immune evasion, and disease pathology. Bloodstream African trypanosomes produce membranous nanotubes that originate from the flagellar membrane and disassociate into free extracellular vesicles (EVs). Trypanosome EVs contain several flagellar proteins that contribute to virulence, and Trypanosoma brucei rhodesiense EVs contain the serum resistance-associated protein (SRA) necessary for human infectivity. T. b. rhodesiense EVs transfer SRA to non-human infectious trypanosomes, allowing evasion of human innate immunity. Trypanosome EVs can also fuse with mammalian erythrocytes, resulting in rapid erythrocyte clearance and anemia. These data indicate that trypanosome EVs are organelles mediating non-hereditary virulence factor transfer and causing host erythrocyte remodeling, inducing anemia.
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Affiliation(s)
- Anthony J Szempruch
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
| | - Steven E Sykes
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
| | - Rudo Kieft
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
| | - Lauren Dennison
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
| | - Allison C Becker
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
| | - Anzio Gartrell
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
| | - William J Martin
- Animal Health Research Center, University of Georgia, Athens, GA 30602, USA
| | - Ernesto S Nakayasu
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352, USA
| | - Igor C Almeida
- Border Biomedical Research Center, Department of Biological Sciences, University of Texas, El Paso, TX 79968, USA
| | - Stephen L Hajduk
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA.
| | - John M Harrington
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA.
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Ethyl Pyruvate Emerges as a Safe and Fast Acting Agent against Trypanosoma brucei by Targeting Pyruvate Kinase Activity. PLoS One 2015; 10:e0137353. [PMID: 26340747 PMCID: PMC4560413 DOI: 10.1371/journal.pone.0137353] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Accepted: 08/14/2015] [Indexed: 12/25/2022] Open
Abstract
Background Human African Trypanosomiasis (HAT) also called sleeping sickness is an infectious disease in humans caused by an extracellular protozoan parasite. The disease, if left untreated, results in 100% mortality. Currently available drugs are full of severe drawbacks and fail to escape the fast development of trypanosoma resistance. Due to similarities in cell metabolism between cancerous tumors and trypanosoma cells, some of the current registered drugs against HAT have also been tested in cancer chemotherapy. Here we demonstrate for the first time that the simple ester, ethyl pyruvate, comprises such properties. Results The current study covers the efficacy and corresponding target evaluation of ethyl pyruvate on T. brucei cell lines using a combination of biochemical techniques including cell proliferation assays, enzyme kinetics, phasecontrast microscopic video imaging and ex vivo toxicity tests. We have shown that ethyl pyruvate effectively kills trypanosomes most probably by net ATP depletion through inhibition of pyruvate kinase (Ki = 3.0±0.29 mM). The potential of ethyl pyruvate as a trypanocidal compound is also strengthened by its fast acting property, killing cells within three hours post exposure. This has been demonstrated using video imaging of live cells as well as concentration and time dependency experiments. Most importantly, ethyl pyruvate produces minimal side effects in human red cells and is known to easily cross the blood-brain-barrier. This makes it a promising candidate for effective treatment of the two clinical stages of sleeping sickness. Trypanosome drug-resistance tests indicate irreversible cell death and a low incidence of resistance development under experimental conditions. Conclusion Our results present ethyl pyruvate as a safe and fast acting trypanocidal compound and show that it inhibits the enzyme pyruvate kinase. Competitive inhibition of this enzyme was found to cause ATP depletion and cell death. Due to its ability to easily cross the blood-brain-barrier, ethyl pyruvate could be considered as new candidate agent to treat the hemolymphatic as well as neurological stages of sleeping sickness.
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