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New Insights on Heme Uptake in Leishmania spp. Int J Mol Sci 2022; 23:ijms231810501. [PMID: 36142411 PMCID: PMC9504327 DOI: 10.3390/ijms231810501] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 09/02/2022] [Accepted: 09/06/2022] [Indexed: 11/20/2022] Open
Abstract
The protozoan parasite Leishmania, responsible for leishmaniasis, is one of the few aerobic organisms that cannot synthesize the essential molecule heme. Therefore, it has developed specialized pathways to scavenge it from its host. In recent years, some proteins involved in the import of heme, such as LHR1 and LFLVCRB, have been identified, but relevant aspects regarding the process remain unknown. Here, we characterized the kinetics of the uptake of the heme analogue Zn(II) Mesoporphyrin IX (ZnMP) in Leishmania major promastigotes as a model of a parasite causing cutaneous leishmaniasis with special focus on the force that drives the process. We found that ZnMP uptake is an active, inducible, and pH-dependent process that does not require a plasma membrane proton gradient but requires the presence of the monovalent cations Na+ and/or K+. In addition, we demonstrated that this parasite can efflux this porphyrin against a concentration gradient. We also found that ZnMP uptake differs among different dermotropic or viscerotropic Leishmania species and does not correlate with LHR1 or LFLVCRB expression levels. Finally, we showed that these transporters have only partially overlapping functions. Altogether, these findings contribute to a deeper understanding of an important process in the biology of this parasite.
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Santiago C, Ortega-Tenezaca B, Barbolla I, Fundora-Ortiz B, Arrasate S, Dea-Ayuela MA, González-Díaz H, Sotomayor N, Lete E. Prediction of Antileishmanial Compounds: General Model, Preparation, and Evaluation of 2-Acylpyrrole Derivatives. J Chem Inf Model 2022; 62:3928-3940. [PMID: 35946598 PMCID: PMC9986876 DOI: 10.1021/acs.jcim.2c00731] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In this work, the SOFT.PTML tool has been used to pre-process a ChEMBL dataset of pre-clinical assays of antileishmanial compound candidates. A comparative study of different ML algorithms, such as logistic regression (LOGR), support vector machine (SVM), and random forests (RF), has shown that the IFPTML-LOGR model presents excellent values of specificity and sensitivity (81-98%) in training and validation series. The use of this software has been illustrated with a practical case study focused on a series of 28 derivatives of 2-acylpyrroles 5a,b, obtained through a Pd(II)-catalyzed C-H radical acylation of pyrroles. Their in vitro leishmanicidal activity against visceral (L. donovani) and cutaneous (L. amazonensis) leishmaniasis was evaluated finding that compounds 5bc (IC50 = 30.87 μM, SI > 10.17) and 5bd (IC50 = 16.87 μM, SI > 10.67) were approximately 6-fold more selective than the drug of reference (miltefosine) in in vitro assays against L. amazonensis promastigotes. In addition, most of the compounds showed low cytotoxicity, CC50 > 100 μg/mL in J774 cells. Interestingly, the IFPMTL-LOGR model predicts correctly the relative biological activity of these series of acylpyrroles. A computational high-throughput screening (cHTS) study of 2-acylpyrroles 5a,b has been performed calculating >20,700 activity scores vs a large space of 647 assays involving multiple Leishmania species, cell lines, and potential target proteins. Overall, the study demonstrates that the SOFT.PTML all-in-one strategy is useful to obtain IFPTML models in a friendly interface making the work easier and faster than before. The present work also points to 2-acylpyrroles as new lead compounds worthy of further optimization as antileishmanial hits.
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Affiliation(s)
- Carlos Santiago
- Departamento de Química Orgánica e Inorgánica, Facultad de Ciencia y Tecnología, Universidad del País Vasco / Euskal Herriko Unibertsitatea UPV/EHU, Apdo. 644, 48080 Bilbao, Spain
| | - Bernabé Ortega-Tenezaca
- Department of Computer Science and Information Technologies, University of A Coruña (UDC), 15071, A Coruña, Spain
| | - Iratxe Barbolla
- Departamento de Química Orgánica e Inorgánica, Facultad de Ciencia y Tecnología, Universidad del País Vasco / Euskal Herriko Unibertsitatea UPV/EHU, Apdo. 644, 48080 Bilbao, Spain.,BIOFISIKA. Basque Center for Biophysics CSIC-UPV/EHU, 48940, Bilbao, Spain
| | - Brenda Fundora-Ortiz
- Departamento de Química Orgánica e Inorgánica, Facultad de Ciencia y Tecnología, Universidad del País Vasco / Euskal Herriko Unibertsitatea UPV/EHU, Apdo. 644, 48080 Bilbao, Spain
| | - Sonia Arrasate
- Departamento de Química Orgánica e Inorgánica, Facultad de Ciencia y Tecnología, Universidad del País Vasco / Euskal Herriko Unibertsitatea UPV/EHU, Apdo. 644, 48080 Bilbao, Spain
| | - María Auxiliadora Dea-Ayuela
- Departamento de Farmacia, Facultad de Ciencias de la Salud, Universidad CEU Cardenal Herrera, 46115 Alfara del Patriarca, Valencia, Spain
| | - Humberto González-Díaz
- Departamento de Química Orgánica e Inorgánica, Facultad de Ciencia y Tecnología, Universidad del País Vasco / Euskal Herriko Unibertsitatea UPV/EHU, Apdo. 644, 48080 Bilbao, Spain.,BIOFISIKA. Basque Center for Biophysics CSIC-UPV/EHU, 48940, Bilbao, Spain.,IKERBASQUE, Basque Foundation for Science, 48011 Bilbao, Spain
| | - Nuria Sotomayor
- Departamento de Química Orgánica e Inorgánica, Facultad de Ciencia y Tecnología, Universidad del País Vasco / Euskal Herriko Unibertsitatea UPV/EHU, Apdo. 644, 48080 Bilbao, Spain
| | - Esther Lete
- Departamento de Química Orgánica e Inorgánica, Facultad de Ciencia y Tecnología, Universidad del País Vasco / Euskal Herriko Unibertsitatea UPV/EHU, Apdo. 644, 48080 Bilbao, Spain
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Gatreddi S, Pillalamarri V, Vasudevan D, Addlagatta A, Qureshi IA. Unraveling structural insights of ribokinase from Leishmania donovani. Int J Biol Macromol 2019; 136:253-265. [PMID: 31170491 DOI: 10.1016/j.ijbiomac.2019.06.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 05/29/2019] [Accepted: 06/01/2019] [Indexed: 11/16/2022]
Abstract
Ribokinase (RK) is an ATP dependent sugar kinase that enables the entry of ribose in the metabolism. Leishmania accumulates ribose into the cytosol through hydrolysis of nucleosides and by transport from the extracellular environment. Activation by RK is critical to mobilize the ribose into the metabolism of Leishmania. To understand the catalytic role, the crystal structure of RK (LdRK) from L. donovani was determined in the apo and complex forms with several nucleotides (ATP, AMPPCP and ADP) in the presence of Na+ ion. The dual insertion of five amino acid stretches makes LdRK structurally unique from other reported structures of RKs. The structure of LdRK-ATP provided the basis for positioning of γ-phosphate of ATP by conserved -GAGD- motif. Liganded and unliganded structures of LdRK exists in similar conformation, which suggests binding of nucleotides does not make any significant conformational changes in nucleotide-bound structures. Substitution of a conserved asparagine with phenylalanine in ribose binding pocket differentiates the LdRK from other RKs. Glycerol molecule bound in the substrate binding pocket mimics the enzyme-substrate interactions but in turn, hampers the binding of ribose to LdRK. Comparative structural analysis revealed the flexibility of γ-phosphate, which adopts multiple conformations in the absence of divalent metal ion and ribose. Similar to other RKs, LdRK is also dependent on monovalent as well as divalent cations for its catalytic activity.
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Affiliation(s)
- Santhosh Gatreddi
- Department of Biotechnology and Bioinformatics, School of Life Sciences, University of Hyderabad, Hyderabad 500 046, Telangana, India
| | - Vijaykumar Pillalamarri
- CSIR-Indian Institute of Chemical Technology, Applied Biology, Hyderabad 500 007, Telangana, India; Academy of Scientific and Innovative Research (AcSIR), Rafi Marg, New Delhi 110001, India
| | | | - Anthony Addlagatta
- CSIR-Indian Institute of Chemical Technology, Applied Biology, Hyderabad 500 007, Telangana, India; Academy of Scientific and Innovative Research (AcSIR), Rafi Marg, New Delhi 110001, India
| | - Insaf Ahmed Qureshi
- Department of Biotechnology and Bioinformatics, School of Life Sciences, University of Hyderabad, Hyderabad 500 046, Telangana, India.
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Landfear SM. Protean permeases: Diverse roles for membrane transport proteins in kinetoplastid protozoa. Mol Biochem Parasitol 2018; 227:39-46. [PMID: 30590069 DOI: 10.1016/j.molbiopara.2018.12.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 12/13/2018] [Accepted: 12/19/2018] [Indexed: 11/26/2022]
Abstract
Kinetoplastid parasites such as Trypanosoma brucei, Trypanosoma cruzi, and Leishmania species rely upon their insect and vertebrate hosts to provide a plethora of nutrients throughout their life cycles. Nutrients and ions critical for parasite survival are taken up across the parasite plasma membrane by transporters and channels, polytopic membrane proteins that provide substrate-specific pores across the hydrophobic barrier. However, transporters and channels serve a wide range of biological functions beyond uptake of nutrients. This article highlights the diversity of activities that these integral membrane proteins serve and underscores the emerging complexity of their functions.
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Affiliation(s)
- Scott M Landfear
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, Portland, OR, 97239, USA.
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Growth arrested live-attenuated Leishmania infantum KHARON1 null mutants display cytokinesis defect and protective immunity in mice. Sci Rep 2018; 8:11627. [PMID: 30072701 PMCID: PMC6072785 DOI: 10.1038/s41598-018-30076-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Accepted: 07/24/2018] [Indexed: 01/30/2023] Open
Abstract
There is no safe and efficacious vaccine against human leishmaniasis available and live attenuated vaccines have been used as a prophylactic alternative against the disease. In order to obtain an attenuated Leishmania parasite for vaccine purposes, we generated L. infantum KHARON1 (KH1) null mutants (ΔLikh1). This gene was previously associated with growth defects in L. mexicana. ΔLikh1 was obtained and confirmed by PCR, qPCR and Southern blot. We also generate a KH1 complemented line with the introduction of episomal copies of KH1. Although ΔLikh1 promastigote forms exhibited a growth pattern similar to the wild-type line, they differ in morphology without affecting parasite viability. L. infantum KH1-deficient amastigotes were unable to sustain experimental infection in macrophages, forming multinucleate cells which was confirmed by in vivo attenuation phenotype. The cell cycle analysis of ΔLikh1 amastigotes showed arrested cells at G2/M phase. ΔLikh1-immunized mice presented reduced parasite burden upon challenging with virulent L. infantum, when compared to naïve mice. An effect associated with increased Li SLA-specific IgG serum levels and IL-17 production. Thus, ΔLikh1 parasites present an infective-attenuated phenotype due to a cytokinesis defect, whereas it induces immunity against visceral leishmaniasis in mouse model, being a candidate for antileishmanial vaccine purposes.
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Abstract
Glucose transport plays important roles for in vitro growth of insect-stage promastigotes and especially for viability of intramacrophage mammalian host-stage amastigotes of Leishmania mexicana. However, the roles of the three distinct glucose transporters, GT1, GT2, and GT3, in parasite viability inside macrophages and virulence in mice have not been fully explored. Parasite lines expressing GT1 or GT2 alone were strongly impaired in growth inside macrophages, but lines expressing GT3 alone infected macrophages and caused lesions in mice as robustly as wild-type parasites. Notably, GT3 localizes to the endoplasmic reticulum of intracellular amastigotes, suggesting a potential role for salvage of glucose from that organelle for viability of infectious amastigotes. This study establishes the unique role of GT3 for parasite survival inside host macrophages and for robust virulence in infected animals. Glucose transporters are important for viability and infectivity of the disease-causing amastigote stages of Leishmania mexicana. The Δgt1-3 null mutant, in which the 3 clustered glucose transporter genes, GT1, GT2, and GT3, have been deleted, is strongly impaired in growth inside macrophages in vitro. We have now demonstrated that this null mutant is also impaired in virulence in the BALB/c murine model of infection and forms lesions considerably more slowly than wild-type parasites. Previously, we established that amplification of the PIFTC3 gene, which encodes an intraflagellar transport protein, both facilitated and accompanied the isolation of the original Δgt1-3 null mutant generated in extracellular insect-stage promastigotes. We have now isolated Δgt1-3 null mutants without coamplification of PIFTC3. These amplicon-negative null mutants are further impaired in growth as promastigotes, compared to the previously described null mutants containing the PIFTC3 amplification. In contrast, the GT3 glucose transporter plays an especially important role in promoting amastigote viability. A line that expresses only the single glucose transporter GT3 grows as well inside macrophages and induces lesions in animals as robustly as do wild-type amastigotes, but lines expressing only the GT1 or GT2 transporters replicate poorly in macrophages. Strikingly, GT3 is restricted largely to the endoplasmic reticulum in intracellular amastigotes. This observation raises the possibility that GT3 may play an important role as an intracellular glucose transporter in the infectious stage of the parasite life cycle. IMPORTANCE Glucose transport plays important roles for in vitro growth of insect-stage promastigotes and especially for viability of intramacrophage mammalian host-stage amastigotes of Leishmania mexicana. However, the roles of the three distinct glucose transporters, GT1, GT2, and GT3, in parasite viability inside macrophages and virulence in mice have not been fully explored. Parasite lines expressing GT1 or GT2 alone were strongly impaired in growth inside macrophages, but lines expressing GT3 alone infected macrophages and caused lesions in mice as robustly as wild-type parasites. Notably, GT3 localizes to the endoplasmic reticulum of intracellular amastigotes, suggesting a potential role for salvage of glucose from that organelle for viability of infectious amastigotes. This study establishes the unique role of GT3 for parasite survival inside host macrophages and for robust virulence in infected animals.
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Belmonte-Reche E, Martínez-García M, Guédin A, Zuffo M, Arévalo-Ruiz M, Doria F, Campos-Salinas J, Maynadier M, López-Rubio JJ, Freccero M, Mergny JL, Pérez-Victoria JM, Morales JC. G-Quadruplex Identification in the Genome of Protozoan Parasites Points to Naphthalene Diimide Ligands as New Antiparasitic Agents. J Med Chem 2018; 61:1231-1240. [PMID: 29323491 PMCID: PMC6148440 DOI: 10.1021/acs.jmedchem.7b01672] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
![]()
G-quadruplexes
(G4) are DNA secondary structures that take part
in the regulation of gene expression. Putative G4 forming sequences
(PQS) have been reported in mammals, yeast, bacteria, and viruses.
Here, we present PQS searches on the genomes of T. brucei,
L. major, and P. falciparum. We found telomeric
sequences and new PQS motifs. Biophysical experiments showed that
EBR1, a 29 nucleotide long highly repeated PQS in T. brucei, forms a stable G4 structure. G4 ligands based on carbohydrate conjugated
naphthalene diimides (carb-NDIs) that bind G4’s including hTel
could bind EBR1 with selectivity versus dsDNA. These ligands showed
important antiparasitic activity. IC50 values were in the
nanomolar range against T. brucei with high selectivity
against MRC-5 human cells. Confocal microscopy confirmed these ligands
localize in the nucleus and kinetoplast of T. brucei suggesting they can reach their potential G4 targets. Cytotoxicity
and zebrafish toxicity studies revealed sugar conjugation reduces
intrinsic toxicity of NDIs.
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Affiliation(s)
- Efres Belmonte-Reche
- Department of Biochemistry and Molecular Pharmacology, Instituto de Parasitología y Biomedicina, CSIC , PTS Granada, Avda. del Conocimiento, 17, 18016 Armilla, Granada, Spain
| | - Marta Martínez-García
- Department of Biochemistry and Molecular Pharmacology, Instituto de Parasitología y Biomedicina, CSIC , PTS Granada, Avda. del Conocimiento, 17, 18016 Armilla, Granada, Spain
| | - Aurore Guédin
- ARNA Laboratory, Université de Bordeaux, Inserm U1212, CNRS UMR5320, Institut Européen de Chimie Biologie (IECB), 2 Rue Robert Escarpit, 33607 Pessac, France
| | - Michela Zuffo
- Department of Chemistry, University of Pavia , Via Taramelli 10, 27100 Pavia, Italy
| | - Matilde Arévalo-Ruiz
- Department of Biochemistry and Molecular Pharmacology, Instituto de Parasitología y Biomedicina, CSIC , PTS Granada, Avda. del Conocimiento, 17, 18016 Armilla, Granada, Spain
| | - Filippo Doria
- Department of Chemistry, University of Pavia , Via Taramelli 10, 27100 Pavia, Italy
| | - Jenny Campos-Salinas
- Department of Biochemistry and Molecular Pharmacology, Instituto de Parasitología y Biomedicina, CSIC , PTS Granada, Avda. del Conocimiento, 17, 18016 Armilla, Granada, Spain
| | - Marjorie Maynadier
- Dynamique des Interactions Membranaires Normales et Pathologiques, CNRS UMR 5235, Université de Montpellier, 34095 Montpellier, France
| | - José Juan López-Rubio
- CNRS, 5290, IRD 224, University of Montpellier (UMR "MiVEGEC"), INSERM, 34394 Montpellier, France
| | - Mauro Freccero
- Department of Chemistry, University of Pavia , Via Taramelli 10, 27100 Pavia, Italy
| | - Jean-Louis Mergny
- ARNA Laboratory, Université de Bordeaux, Inserm U1212, CNRS UMR5320, Institut Européen de Chimie Biologie (IECB), 2 Rue Robert Escarpit, 33607 Pessac, France.,Institute of Biophysics , AS CR, v.v.i. Kralovopolska 135, 612 65 Brno, Czech Republic
| | - José María Pérez-Victoria
- Department of Biochemistry and Molecular Pharmacology, Instituto de Parasitología y Biomedicina, CSIC , PTS Granada, Avda. del Conocimiento, 17, 18016 Armilla, Granada, Spain
| | - Juan Carlos Morales
- Department of Biochemistry and Molecular Pharmacology, Instituto de Parasitología y Biomedicina, CSIC , PTS Granada, Avda. del Conocimiento, 17, 18016 Armilla, Granada, Spain
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The role of membrane transporters in Leishmania virulence. Emerg Top Life Sci 2017; 1:601-611. [DOI: 10.1042/etls20170119] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Revised: 11/19/2017] [Accepted: 11/23/2017] [Indexed: 11/17/2022]
Abstract
Leishmania are parasitic protozoa which infect humans and cause severe morbidity and mortality. Leishmania parasitise as extracellular promastigotes in the insect vector and as intracellular amastigotes in the mammalian host. Cycling between hosts involves implementation of stringent and co-ordinated responses to shifting environmental conditions. One of the key dynamic aspects of Leishmania biology is substrate acquisition and metabolism. Genomic analyses have revealed that Leishmania encode many putative membrane transporters, many of which are differentially expressed during the parasite life cycle. Only a small fraction of these transporters, however, have been functionally characterised. Currently, most information is available about nutrient transporters, mainly involved in carbohydrate, amino acid, nucleobase and nucleoside, cofactor, and ion acquisition. Several have apparent roles in Leishmania virulence and will be discussed in this perspective.
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Akpunarlieva S, Weidt S, Lamasudin D, Naula C, Henderson D, Barrett M, Burgess K, Burchmore R. Integration of proteomics and metabolomics to elucidate metabolic adaptation in Leishmania. J Proteomics 2017; 155:85-98. [DOI: 10.1016/j.jprot.2016.12.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Revised: 12/13/2016] [Accepted: 12/16/2016] [Indexed: 01/16/2023]
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Stiles JK, Hicock PI, Shah PH, Meade JC. Genomic organization, transcription, splicing and gene regulation inLeishmania. ANNALS OF TROPICAL MEDICINE AND PARASITOLOGY 2016. [DOI: 10.1080/00034983.1999.11813485] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Fiebig M, Kelly S, Gluenz E. Comparative Life Cycle Transcriptomics Revises Leishmania mexicana Genome Annotation and Links a Chromosome Duplication with Parasitism of Vertebrates. PLoS Pathog 2015; 11:e1005186. [PMID: 26452044 PMCID: PMC4599935 DOI: 10.1371/journal.ppat.1005186] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Accepted: 09/03/2015] [Indexed: 02/07/2023] Open
Abstract
Leishmania spp. are protozoan parasites that have two principal life cycle stages: the motile promastigote forms that live in the alimentary tract of the sandfly and the amastigote forms, which are adapted to survive and replicate in the harsh conditions of the phagolysosome of mammalian macrophages. Here, we used Illumina sequencing of poly-A selected RNA to characterise and compare the transcriptomes of L. mexicana promastigotes, axenic amastigotes and intracellular amastigotes. These data allowed the production of the first transcriptome evidence-based annotation of gene models for this species, including genome-wide mapping of trans-splice sites and poly-A addition sites. The revised genome annotation encompassed 9,169 protein-coding genes including 936 novel genes as well as modifications to previously existing gene models. Comparative analysis of gene expression across promastigote and amastigote forms revealed that 3,832 genes are differentially expressed between promastigotes and intracellular amastigotes. A large proportion of genes that were downregulated during differentiation to amastigotes were associated with the function of the motile flagellum. In contrast, those genes that were upregulated included cell surface proteins, transporters, peptidases and many uncharacterized genes, including 293 of the 936 novel genes. Genome-wide distribution analysis of the differentially expressed genes revealed that the tetraploid chromosome 30 is highly enriched for genes that were upregulated in amastigotes, providing the first evidence of a link between this whole chromosome duplication event and adaptation to the vertebrate host in this group. Peptide evidence for 42 proteins encoded by novel transcripts supports the idea of an as yet uncharacterised set of small proteins in Leishmania spp. with possible implications for host-pathogen interactions.
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Affiliation(s)
- Michael Fiebig
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford, United Kingdom
| | - Steven Kelly
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford, United Kingdom
- * E-mail: (SK); (EG)
| | - Eva Gluenz
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford, United Kingdom
- * E-mail: (SK); (EG)
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Landfear SM, Tran KD, Sanchez MA. Flagellar membrane proteins in kinetoplastid parasites. IUBMB Life 2015; 67:668-76. [PMID: 26599841 DOI: 10.1002/iub.1411] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Accepted: 08/06/2015] [Indexed: 11/06/2022]
Abstract
All kinetoplastid parasites, including protozoa such as Leishmania species, Trypanosoma brucei, and Trypanosoma cruzi that cause devastating diseases in humans and animals, are flagellated throughout their life cycles. Although flagella were originally thought of primarily as motility organelles, flagellar functions in other critical processes, especially in sensing and signal transduction, have become more fully appreciated in the recent past. The flagellar membrane is a highly specialized subdomain of the surface membrane, and flagellar membrane proteins are likely to be critical components for all the biologically important roles of flagella. In this review, we summarize recent discoveries relevant to flagellar membrane proteins in these parasites, including the identification of such proteins, investigation of their biological functions, and mechanisms of selective trafficking to the flagellar membrane. Prospects for future investigations and current unsolved problems are highlighted.
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Affiliation(s)
- Scott M Landfear
- Department of Molecular Microbiology and Immunology, Oregon Health and Sciences University, Portland, OR, USA
| | - Khoa D Tran
- Department of Molecular Microbiology and Immunology, Oregon Health and Sciences University, Portland, OR, USA
| | - Marco A Sanchez
- Department of Molecular Microbiology and Immunology, Oregon Health and Sciences University, Portland, OR, USA
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Rodriguez-Contreras D, Aslan H, Feng X, Tran K, Yates PA, Kamhawi S, Landfear SM. Regulation and biological function of a flagellar glucose transporter in Leishmania mexicana: a potential glucose sensor. FASEB J 2014; 29:11-24. [PMID: 25300620 DOI: 10.1096/fj.14-251991] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
In Leishmania mexicana parasites, a unique glucose transporter, LmxGT1, is selectively targeted to the flagellar membrane, suggesting a possible sensory role that is often associated with ciliary membrane proteins. Expression of LmxGT1 is down-regulated ∼20-fold by increasing cell density but is up-regulated ∼50-fold by depleting glucose from the medium, and the permease is strongly down-regulated when flagellated insect-stage promastigotes invade mammalian macrophages and transform into intracellular amastigotes. Regulation of LmxGT1 expression by glucose and during the lifecycle operates at the level of protein stability. Significantly, a ∆lmxgt1 null mutant, grown in abundant glucose, undergoes catastrophic loss of viability when parasites deplete glucose from the medium, a property not exhibited by wild-type or add-back lines. These results suggest that LmxGT1 may function as a glucose sensor that allows parasites to enter the stationary phase when they deplete glucose and that in the absence of this sensor, parasites do not maintain viability when they run out of glucose. However, alternate roles for LmxGT1 in monitoring glucose availability are considered. The absence of known sensory receptors with defined ligands and biologic functions in Leishmania and related kinetoplastid parasites underscores the potential significance of these observations.
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Affiliation(s)
| | - Hamide Aslan
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Xiuhong Feng
- Departments of Molecular Microbiology & Immunology and
| | - Khoa Tran
- Departments of Molecular Microbiology & Immunology and
| | - Phillip A Yates
- Biochemistry & Molecular Biology, Oregon Health & Science University, Portland, Oregon, USA; and
| | - Shaden Kamhawi
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
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Rodriguez-Contreras D, Hamilton N. Gluconeogenesis in Leishmania mexicana: contribution of glycerol kinase, phosphoenolpyruvate carboxykinase, and pyruvate phosphate dikinase. J Biol Chem 2014; 289:32989-3000. [PMID: 25288791 DOI: 10.1074/jbc.m114.569434] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Gluconeogenesis is an active pathway in Leishmania amastigotes and is essential for their survival within the mammalian cells. However, our knowledge about this pathway in trypanosomatids is very limited. We investigated the role of glycerol kinase (GK), phosphoenolpyruvate carboxykinase (PEPCK), and pyruvate phosphate dikinase (PPDK) in gluconeogenesis by generating the respective Leishmania mexicana Δgk, Δpepck, and Δppdk null mutants. Our results demonstrated that indeed GK, PEPCK, and PPDK are key players in the gluconeogenesis pathway in Leishmania, although stage-specific differences in their contribution to this pathway were found. GK participates in the entry of glycerol in promastigotes and amastigotes; PEPCK participates in the entry of aspartate in promastigotes, and PPDK is involved in the entry of alanine in amastigotes. Furthermore, the majority of alanine enters into the pathway via decarboxylation of pyruvate in promastigotes, whereas pathway redundancy is suggested for the entry of aspartate in amastigotes. Interestingly, we also found that l-lactate, an abundant glucogenic precursor in mammals, was used by Leishmania amastigotes to synthesize mannogen, entering the pathway through PPDK. On the basis of these new results, we propose a revision in the current model of gluconeogenesis in Leishmania, emphasizing the differences between amastigotes and promastigotes. This work underlines the importance of studying the trypanosomatid intracellular life cycle stages to gain a better understanding of the pathologies caused in humans.
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Affiliation(s)
- Dayana Rodriguez-Contreras
- From the Department of Molecular Microbiology and Immunology, Oregon Health and Science University, Portland, Oregon 97239
| | - Nicklas Hamilton
- From the Department of Molecular Microbiology and Immunology, Oregon Health and Science University, Portland, Oregon 97239
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Knüsel S, Roditi I. Insights into the regulation of GPEET procyclin during differentiation from early to late procyclic forms of Trypanosoma brucei. Mol Biochem Parasitol 2013; 191:66-74. [PMID: 24076427 DOI: 10.1016/j.molbiopara.2013.09.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Revised: 09/17/2013] [Accepted: 09/18/2013] [Indexed: 11/19/2022]
Abstract
The procyclic form of Trypanosoma brucei colonises the gut of its insect vector, the tsetse fly. GPEET and EP procyclins constitute the parasite's surface coat at this stage of the life cycle, and the presence or absence of GPEET distinguishes between early and late procyclic forms, respectively. Differentiation from early to late procyclic forms in vivo occurs in the fly midgut and can be mimicked in culture. Our analysis of this transition in vitro delivered new insights into the process of GPEET repression. First, we could show that parasites followed a concrete sequence of events upon triggering differentiation: after undergoing an initial growth arrest, cells lost GPEET protein, and finally late procyclic forms resumed proliferation. Second, we determined the stability of both GPEET and EP mRNA during differentiation. GPEET mRNA is exceptionally stable in early procyclic forms, with a half-life >6h. The GPEET mRNA detected in late procyclic form cultures is a mixture of transcripts from both bona fide late procyclic forms and GPEET-positive 'laggard' parasites present in these cultures. However, its stability was clearly reduced during differentiation and in late procyclic form cultures. Alternatively processed GPEET transcripts were enriched in samples from late procyclic forms, suggesting that altered mRNA processing might contribute to repression of GPEET in this developmental stage. In addition, we detected GPEET transcripts with non-templated oligo(U) tails that were enriched in late procyclic forms. To the best of our knowledge, this is the first study reporting a uridylyl-tailed, nuclear-encoded mRNA species in trypanosomatids or any other protozoa.
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Affiliation(s)
- Sebastian Knüsel
- Institute of Cell Biology, University of Bern, Baltzerstrasse 4, CH-3012 Bern, Switzerland; Graduate School of Cellular and Biomedical Sciences, University of Bern, Freiestrasse 1, CH-3012 Bern, Switzerland
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16
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Lynn MA, Marr AK, McMaster WR. Differential quantitative proteomic profiling of Leishmania infantum and Leishmania mexicana density gradient separated membranous fractions. J Proteomics 2013; 82:179-92. [PMID: 23466312 DOI: 10.1016/j.jprot.2013.02.010] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Revised: 02/08/2013] [Accepted: 02/09/2013] [Indexed: 12/22/2022]
Abstract
UNLABELLED Leishmaniasis, caused by infection with Leishmania, is a major public health concern affecting more than 20million people globally. Leishmania has a digenetic lifecycle consisting of an extracellular flagellated promastigote, adapted to live in the mid-gut of the sand fly host and an aflagellated intracellular amastigote that resides within the macrophage of the mammalian host. Leishmania mexicana and Leishmania infantum are causative agents of cutaneous and visceral leishmaniasis, respectively. Membrane proteins play a pivotal role in host-pathogen interactions and in regulatory pathways. As the genome of Leishmania is essentially constitutively expressed, regulation of protein expression during differentiation occurs post-transcriptionally and/or post-translationally. Quantitative mass spectrometry using iTRAQ labeling identified differences in the proteomes of density gradient separated membranous fractions of promastigote and amastigote life-stages. We identified 189 L. infantum and 107 L. mexicana non-redundant proteins of which 20-40% showed differential expression levels between promastigote and amastigote lifecycle stages. Differentially expressed proteins mapped to several pathways including cell motility, metabolism, and infectivity as well as virulence factors such as eEF-1α, amastin and leishmanolysin (GP63). Western blot analysis validated iTRAQ quantitation for leishmanolysin. Focusing on differentially expressed proteins essential for pathogenesis, may ultimately lead to the identification of novel potential therapeutic targets. BIOLOGICAL SIGNIFICANCE Leishmania, protozoan parasites of the Trypanosomatidae family, are the causative agents of leishmaniasis that represents a major public health concern affecting more than 20million people globally Membrane associated proteins play a pivotal role in host-pathogen interactions and in regulatory pathways. Quantitative proteomic analysis of the membranous fractions from L. mexicana and L. infantum (causative agents of cutaneous and visceral leishmaniasis, respectively) identified a number of proteins that may have important stage-specific functions in either the sand fly or mammalian host. The function of these proteins includes roles in virulence, as well as differences in metabolic process between life stages. Many of the proteins identified may act as virulence factors playing significant roles in parasite invasion, host-parasite interaction or parasite survival and thus may have therapeutic potential as drug target candidates.
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Affiliation(s)
- Miriam A Lynn
- Infection and Immunity Research Centre, Vancouver Coastal Health Research Institute, 2660 Oak Street, Vancouver, B.C., V6H 3Z6, Canada
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Feng X, Rodriguez-Contreras D, Polley T, Lye LF, Scott D, Burchmore RJS, Beverley SM, Landfear SM. 'Transient' genetic suppression facilitates generation of hexose transporter null mutants in Leishmania mexicana. Mol Microbiol 2012; 87:412-29. [PMID: 23170981 DOI: 10.1111/mmi.12106] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/15/2012] [Indexed: 11/26/2022]
Abstract
The genome of Leishmania mexicana encompasses a cluster of three glucose transporter genes designated LmxGT1, LmxGT2 and LmxGT3. Functional and genetic studies of a cluster null mutant (Δlmxgt1-3) have dissected the roles of these proteins in Leishmania metabolism and virulence. However, null mutants were recovered at very low frequency, and comparative genome hybridizations revealed that Δlmxgt1-3 mutants contained a linear extrachromosomal 40 kb amplification of a region on chromosome 29 not amplified in wild type parasites. These data suggested a model where this 29-40k amplicon encoded a second site suppressor contributing to parasite survival in the absence of GT1-3 function. To test this, we quantified the frequency of recovery of knockouts in the presence of individual overexpressed open reading frames covering the 29-40k amplicon. The data mapped the suppressor activity to PIFTC3, encoding a component of the intraflagellar transport pathway. We discuss possible models by which PIFTC3 might act to facilitate loss of GTs specifically. Surprisingly, by plasmid segregation we showed that continued PIFTC3 overexpression was not required for Δlmxgt1-3 viability. These studies provide the first evidence that genetic suppression can occur by providing critical biological functions transiently. This novel form of genetic suppression may extend to other genes, pathways and organisms.
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Affiliation(s)
- Xiuhong Feng
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, Portland, OR 97239, USA
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18
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On the evolution of hexose transporters in kinetoplastid Protozoans [corrected]. PLoS One 2012; 7:e36303. [PMID: 22567148 PMCID: PMC3342237 DOI: 10.1371/journal.pone.0036303] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2011] [Accepted: 04/02/2012] [Indexed: 11/24/2022] Open
Abstract
Glucose, an almost universally used energy and carbon source, is processed through several well-known metabolic pathways, primarily glycolysis. Glucose uptake is considered to be the first step in glycolysis. In kinetoplastids, a protozoan group that includes relevant human pathogens, the importance of glucose uptake in different phases of the life cycles is well established, and hexose transporters have been proposed as targets for therapeutic drugs. However, little is known about the evolutionary history of these hexose transporters. Hexose transporters contain an intracellular N- and C- termini, and 12 transmembrane spans connected by alternate intracellular and extracellular loops. In the present work we tested the hypothesis that the evolutionary rate of the transmembrane span is different from that of the whole sequence and that it is possible to define evolutionary units inside the sequence. The phylogeny of whole molecules was compared to that of their transmembrane spans and the loops connecting the transmembrane spans. We show that the evolutionary units in these proteins primarily consist of clustered rather than individual transmembrane spans. These analyses demonstrate that there are evolutionary constraints on the organization of these proteins; more specifically, the order of the transmembrane spans along the protein is highly conserved. Finally, we defined a signature sequence for the identification of kinetoplastid hexose transporters.
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Tran KD, Rodriguez-Contreras D, Shinde U, Landfear SM. Both sequence and context are important for flagellar targeting of a glucose transporter. J Cell Sci 2012; 125:3293-8. [PMID: 22467850 DOI: 10.1242/jcs.103028] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Many of the cilia- and flagella-specific integral membrane proteins identified to date function to sense the extracellular milieu, and there is considerable interest in defining pathways for targeting such proteins to these sensory organelles. The flagellar glucose transporter of Leishmania mexicana, LmxGT1, is targeted selectively to the flagellar membrane, whereas two other isoforms, LmxGT2 and LmxGT3, are targeted to the pellicular plasma membrane of the cell body. To define the flagellar targeting signal, deletions and point mutations were generated in the N-terminal hydrophilic domain of LmxGT1, which mediates flagellar localization. Three amino acids, N95-P96-M97, serve critical roles in flagellar targeting, resulting in strong mistargeting phenotypes when mutagenized. However, to facilitate flagellar targeting of other non-flagellar membrane proteins, it was necessary to attach a larger region surrounding the NPM motif containing amino acids 81-113. Molecular modeling suggests that this region might present the critical NPM residues at the surface of the N-terminal domain. It is likely that the NPM motif is recognized by currently unknown protein-binding partners that mediate flagellar targeting of membrane-associated proteins.
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Affiliation(s)
- Khoa D Tran
- Department of Molecular Microbiology and Immunology, Oregon Health and Science University, Portland, OR 97239, USA
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20
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Slavic K, Krishna S, Derbyshire ET, Staines HM. Plasmodial sugar transporters as anti-malarial drug targets and comparisons with other protozoa. Malar J 2011; 10:165. [PMID: 21676209 PMCID: PMC3135577 DOI: 10.1186/1475-2875-10-165] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2011] [Accepted: 06/15/2011] [Indexed: 01/28/2023] Open
Abstract
Glucose is the primary source of energy and a key substrate for most cells. Inhibition of cellular glucose uptake (the first step in its utilization) has, therefore, received attention as a potential therapeutic strategy to treat various unrelated diseases including malaria and cancers. For malaria, blood forms of parasites rely almost entirely on glycolysis for energy production and, without energy stores, they are dependent on the constant uptake of glucose. Plasmodium falciparum is the most dangerous human malarial parasite and its hexose transporter has been identified as being the major glucose transporter. In this review, recent progress regarding the validation and development of the P. falciparum hexose transporter as a drug target is described, highlighting the importance of robust target validation through both chemical and genetic methods. Therapeutic targeting potential of hexose transporters of other protozoan pathogens is also reviewed and discussed.
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Affiliation(s)
- Ksenija Slavic
- Centre for Infection, Division of Cellular and Molecular Medicine, St. George's, University of London, Cranmer Terrace, London SW17 0RE, UK.
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21
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Vince JE, Tull D, Landfear S, McConville MJ. Lysosomal degradation of Leishmania hexose and inositol transporters is regulated in a stage-, nutrient- and ubiquitin-dependent manner. Int J Parasitol 2011; 41:791-800. [PMID: 21447343 DOI: 10.1016/j.ijpara.2011.02.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2010] [Revised: 02/07/2011] [Accepted: 02/09/2011] [Indexed: 11/29/2022]
Abstract
Leishmania parasites experience variable nutrient levels as they cycle between the extracellular promastigote stage in the sandfly vector and the obligate intracellular amastigote stage in the mammalian host. Here we show that the surface expression of three Leishmania mexicana hexose and myo-inositol transporters is regulated in both a stage-specific and nutrient-dependent manner. GFP-chimeras of functionally active hexose transporters, LmGT2 and LmGT3, and the myo-inositol transporter, MIT, were primarily expressed in the cell body plasma membrane in rapidly dividing promastigote stages. However MIT-GFP was mostly rerouted to the multivesicular tubule (MVT)-lysosome when promastigotes reached stationary phase growth and all three nutrient transporters were targeted to the amastigote lysosome following transformation to in vitro differentiated or in vivo imaged amastigote stages. This stage-specific decrease in surface expression of GFP-tagged transporters correlated with decreased hexose or myo-inositol uptake in stationary phase promastigotes and amastigotes. The MVT-lysosme targeting of the MIT-GFP protein was reversed when promastigotes were deprived of myo-inositol, indicating that nutrient signals can override stage-specific changes in transporter distribution. The surface expression of the hexose and myo-inositol transporters was not regulated by interactions with the subpellicular cytoskeleton, as both classes of transporters associated with detergent-resistant membranes. LmGT3-GFP and MIT-GFP proteins C-terminally modified with mono-ubiquitin were constitutively transported to the MVT-lysosome, suggesting that ubiquitination may play a key role in regulating the subcellular distribution of these transporters and parasite adaptation to different nutrient conditions.
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Affiliation(s)
- James E Vince
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Flemington Rd, Parkville, Victoria 3010, Australia.
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22
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Nutrient transport and pathogenesis in selected parasitic protozoa. EUKARYOTIC CELL 2011; 10:483-93. [PMID: 21216940 DOI: 10.1128/ec.00287-10] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Parasitic protozoa, such as malaria parasites, trypanosomes, and Leishmania, acquire a plethora of nutrients from their hosts, employing transport proteins located in the plasma membrane of the parasite. Application of molecular genetic approaches and the completion of genome projects have allowed the identification and functional characterization of a cohort of transporters and their genes in these parasites. This review focuses on a subset of these permeases that have been studied in some detail, that import critical nutrients, and that provide examples of approaches being undertaken broadly with these and other parasite transporters. Permeases reviewed include those for hexoses, purines, iron, polyamines, carboxylates, and amino acids. Topics of special emphasis include structure-function approaches, critical roles for transporters in parasite viability and physiology, regulation of transporter expression, and subcellular targeting. Investigations of parasite transporters impact a broad spectrum of basic biological problems in these protozoa.
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23
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Murray AS, Lynn MA, McMaster WR. The Leishmania mexicana A600 genes are functionally required for amastigote replication. Mol Biochem Parasitol 2010; 172:80-9. [DOI: 10.1016/j.molbiopara.2010.03.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2009] [Revised: 03/10/2010] [Accepted: 03/14/2010] [Indexed: 12/17/2022]
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24
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Naula CM, Logan FJ, Logan FM, Wong PE, Barrett MP, Burchmore RJ. A glucose transporter can mediate ribose uptake: definition of residues that confer substrate specificity in a sugar transporter. J Biol Chem 2010; 285:29721-8. [PMID: 20601430 PMCID: PMC2943324 DOI: 10.1074/jbc.m110.106815] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Sugars, the major energy source for many organisms, must be transported across biological membranes. Glucose is the most abundant sugar in human plasma and in many other biological systems and has been the primary focus of sugar transporter studies in eukaryotes. We have previously cloned and characterized a family of glucose transporter genes from the protozoan parasite Leishmania. These transporters, called LmGT1, LmGT2, and LmGT3, are homologous to the well characterized glucose transporter (GLUT) family of mammalian glucose transporters. We have demonstrated that LmGT proteins are important for parasite viability. Here we show that one of these transporters, LmGT2, is a more effective carrier of the pentose sugar d-ribose than LmGT3, which has a 6-fold lower relative specificity (Vmax/Km) for ribose. A pair of threonine residues, located in the putative extracellular loops joining transmembrane helices 3 to 4 and 7 to 8, define a filter that limits ribose approaching the exofacial substrate binding pocket in LmGT3. When these threonines are substituted by alanine residues, as found in LmGT2, the LmGT3 permease acquires ribose permease activity that is similar to that of LmGT2. The location of these residues in hydrophilic loops supports recent suggestions that substrate recognition is separated from substrate binding and translocation in this important group of transporters.
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Affiliation(s)
- Christina M Naula
- Faculty of Biomedical and Life Sciences, University of Glasgow, Glasgow G12 8QQ, Scotland, United Kingdom
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25
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Abstract
Glucose and related hexoses play central roles in the biochemistry and metabolism of single-cell parasites such as Leishmania, Trypanosoma, and Plasmodium that are the causative agents of leishmaniasis, African sleeping sickness, and malaria. Glucose transporters and the genes that encode them have been identified in each of these parasites and their functional properties have been scrutinized. These transporters are related in sequence and structure to mammalian facilitative glucose transporters of the SLC2 family, but they are nonetheless quite divergent in sequence. Hexose transporters have been shown to be essential for the viability of the infectious stage of each of these parasites and thus may represent targets for development of novel anti-parasitic drugs. The study of these transporters also illuminates many aspects of the basic biology of Leishmania, trypanosomes, and malaria parasites.
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Whole-genome comparative RNA expression profiling of axenic and intracellular amastigote forms of Leishmania infantum. Mol Biochem Parasitol 2009; 165:32-47. [DOI: 10.1016/j.molbiopara.2008.12.012] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2008] [Revised: 12/13/2008] [Accepted: 12/23/2008] [Indexed: 11/19/2022]
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27
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Feng X, Rodriguez-Contreras D, Buffalo C, Bouwer HGA, Kruvand E, Beverley SM, Landfear SM. Amplification of an alternate transporter gene suppresses the avirulent phenotype of glucose transporter null mutants in Leishmania mexicana. Mol Microbiol 2008; 71:369-81. [PMID: 19017272 DOI: 10.1111/j.1365-2958.2008.06531.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
A glucose transporter null mutant of the parasitic protozoan Leishmania mexicana, in which three linked glucose transporter genes have been deleted by targeted gene replacement, is unable to replicate as amastigote forms within phagolysomes of mammalian host macrophages and is avirulent. Spontaneous suppressors of the null mutant have been isolated that partially restore replication of parasites within macrophages. These suppressor mutants have amplified the gene for an alternative hexose transporter, the LmGT4 permease (previously called the D2 permease), on a circular extrachromosomal element, and they overexpress LmGT4 mRNA and protein. The suppressors have also regained the ability to transport hexoses, and they have reverted other phenotypes of the null mutant exhibiting enhanced resistance to oxidative killing, heat shock and starvation for nutrients, as well as augmented levels of the storage carbohydrate beta-mannan, increased cell size and increased growth as insect stage promastigotes compared with the unsuppressed mutant. Complementation of the null mutant with the LmGT4 gene on a multicopy episomal expression vector also reverted these phenotypes, confirming that suppression results from amplification of the LmGT4 gene. These results underscore the importance of hexose transporters for the infectious stage of the parasite life cycle.
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Affiliation(s)
- Xiuhong Feng
- Department of Molecular Microbiology and Immunology, Oregon Health and Science University, Portland, OR 97239, USA
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28
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Rochette A, Raymond F, Ubeda JM, Smith M, Messier N, Boisvert S, Rigault P, Corbeil J, Ouellette M, Papadopoulou B. Genome-wide gene expression profiling analysis of Leishmania major and Leishmania infantum developmental stages reveals substantial differences between the two species. BMC Genomics 2008; 9:255. [PMID: 18510761 PMCID: PMC2453527 DOI: 10.1186/1471-2164-9-255] [Citation(s) in RCA: 116] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2008] [Accepted: 05/29/2008] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Leishmania parasites cause a diverse spectrum of diseases in humans ranging from spontaneously healing skin lesions (e.g., L. major) to life-threatening visceral diseases (e.g., L. infantum). The high conservation in gene content and genome organization between Leishmania major and Leishmania infantum contrasts their distinct pathophysiologies, suggesting that highly regulated hierarchical and temporal changes in gene expression may be involved. RESULTS We used a multispecies DNA oligonucleotide microarray to compare whole-genome expression patterns of promastigote (sandfly vector) and amastigote (mammalian macrophages) developmental stages between L. major and L. infantum. Seven per cent of the total L. infantum genome and 9.3% of the L. major genome were differentially expressed at the RNA level throughout development. The main variations were found in genes involved in metabolism, cellular organization and biogenesis, transport and genes encoding unknown function. Remarkably, this comparative global interspecies analysis demonstrated that only 10-12% of the differentially expressed genes were common to L. major and L. infantum. Differentially expressed genes are randomly distributed across chromosomes further supporting a posttranscriptional control, which is likely to involve a variety of 3'UTR elements. CONCLUSION This study highlighted substantial differences in gene expression patterns between L. major and L. infantum. These important species-specific differences in stage-regulated gene expression may contribute to the disease tropism that distinguishes L. major from L. infantum.
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Affiliation(s)
- Annie Rochette
- Research Centre in Infectious Diseases, CHUL Research Centre and Department of Medical Biology, Faculty of Medicine, Laval University, Quebec, Canada.
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29
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Landfear SM. Drugs and transporters in kinetoplastid protozoa. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2008; 625:22-32. [PMID: 18365656 DOI: 10.1007/978-0-387-77570-8_3] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Kinetoplastid protozoa express hundreds of membrane transport proteins that allow them to take up nutrients, establish ion gradients, efflux metabolites, translocate compounds from one intracellular compartment to another, and take up or export drugs. The combination of molecular cloning, genetic approaches, and the completed genome projects for Trypanosoma brucei, Leishmania major, and Trypanosoma cruzi have allowed detailed functional analysis of various transporters and predictions about the likely functions of others. Thus many opportunities exist to define the biological and pharmacological properties of parasite transporters whose genes were often difficult to identify in the pregenomic era. A subset of these transporters that are essential for parasite viability could serve as targets for novel drug therapies by identifying compounds that interfere with their uptake functions. Other permeases provide routes for uptake of selectively cytotoxic compounds and can thus be useful for delivery of drugs. Drug resistance may develop in strains where such drug uptake transporters are nonfunctional or in parasites that over-express other permeases that export a drug. A summary of recent work on Leishmania transporters for glucose and for purines is provided as an example of permeases that are being studied in molecular detail.
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Affiliation(s)
- Scott M Landfear
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, Oregon 97239, USA.
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García-Estrada C, Pérez-Pertejo Y, Ordóñez D, Balaña-Fouce R, Reguera RM. Characterization of the 5' region of the Leishmania infantum LORIEN/MAT2 gene cluster and role of LORIEN flanking regions in post-transcriptional regulation. Biochimie 2008; 90:1325-36. [PMID: 18420039 DOI: 10.1016/j.biochi.2008.03.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2007] [Accepted: 03/18/2008] [Indexed: 11/19/2022]
Abstract
LORIEN (encoding a protein that contains a SP-RING/Miz zinc-finger motif present in a group of proteins involved in the Small Ubiquitin-related Modifier -SUMO- conjugation pathway) and MAT2 (encoding the methionine adenosyltransferase -MAT-) genes are arranged as two alternating copies in a head-to-tail configuration, with the LORIEN gene as the first copy of the cluster. The 5880bp preceding the first LORIEN gene copy were compared to the same region of L. major, showing a 93% identity between them. Bioinformatic analysis of this region predicted the presence of a 747-bp ORF encoding a hypothetical protein of 248 amino acids. Transcription of this ORF was confirmed by run-on assays and RT-PCR. Expression of the LORIEN gene was tested in both the promastigote and amastigote stages. Transcription arrest evidenced that LORIEN mRNA stability was very similar in both stages of the parasite life cycle. Protein synthesis inhibition by cycloheximide led to an increase in the steady-state levels of LORIEN transcripts only during the promastigote stage, pointing out to the existence of different stage-dependent mechanisms operating on the post-transcriptional regulation of this gene. The role of the LORIEN untranslated regions (5'UTR and 3'UTR) in post-transcriptional regulation was analysed using the luciferase (luc) reporter gene. Results evidenced that the 5'UTR was responsible for a low reporter gene expression, whereas the intergenic region (IR) between LORIEN and MAT2 genes provided high luc levels. However, the 3'UTR seemed to lack regulatory elements. Basing on these results, a model of regulation for the LORIEN gene is proposed.
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Affiliation(s)
- Carlos García-Estrada
- Departamento de Farmacología y Toxicología (INTOXCAL), Universidad de León, Campus de Vegazana s/n, 24071 León, Spain
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Coordinate regulation of a family of promastigote-enriched mRNAs by the 3'UTR PRE element in Leishmania mexicana. Mol Biochem Parasitol 2007; 157:54-64. [PMID: 18023890 DOI: 10.1016/j.molbiopara.2007.10.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2006] [Revised: 09/11/2007] [Accepted: 10/02/2007] [Indexed: 11/24/2022]
Abstract
Post-transcriptional regulation is a key feature controlling gene expression in the protozoan parasite Leishmania. The nine-nucleotide paraflagellar rod regulatory element (PRE) in the 3'UTR of Leishmania mexicana PFR2 is both necessary and sufficient for the observed 10-fold higher level of PFR2 mRNA in promastigotes compared to amastigotes. It is also found in the 3'UTRs of all known PFR genes. A search of the Leishmania major Friedlin genomic database revealed several genes that share this cis element including a homolog of a heterotrimeric kinesin II subunit, and a gene that shares identity to a homolog of a Plasmodium antigen. In this study, we show that genes that harbor the PRE display promastigote-enriched transcript accumulation ranging from 4- to 15-fold. Northern analysis on episomal block substitution constructs revealed that the regulatory element is necessary for the proper steady-state accumulation of mRNA in L. mexicana paraflagellar rod gene 4 (PFR4). Also we show that the PRE plays a major role in the proper steady-state mRNA accumulation of PFR1, but may not account for the full regulatory mechanism acting on this mRNA. Our evidence suggests that the PRE coordinately regulates the mRNA abundance of not only the PFR family of genes, but also in a larger group of genes that have unrelated functions. Although the PRE alone can regulate some mRNAs, it may also act in concert with additional elements to control other RNA transcripts.
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Lustig Y, Vagima Y, Goldshmidt H, Erlanger A, Ozeri V, Vince J, McConville MJ, Dwyer DM, Landfear SM, Michaeli S. Down-regulation of the trypanosomatid signal recognition particle affects the biogenesis of polytopic membrane proteins but not of signal peptide-containing proteins. EUKARYOTIC CELL 2007; 6:1865-75. [PMID: 17715370 PMCID: PMC2043396 DOI: 10.1128/ec.00134-07] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Protein translocation across the endoplasmic reticulum is mediated by the signal recognition particle (SRP). In this study, the SRP pathway in trypanosomatids was down-regulated by two approaches: RNA interference (RNAi) silencing of genes encoding SRP proteins in Trypanosoma brucei and overexpression of dominant-negative mutants of 7SL RNA in Leptomonas collosoma. The biogenesis of both signal peptide-containing proteins and polytopic membrane proteins was examined using endogenous and green fluorescent protein-fused proteins. RNAi silencing of SRP54 or SRP68 in T. brucei resulted in reduced levels of polytopic membrane proteins, but no effect on the level of signal peptide-containing proteins was observed. When SRP deficiency was achieved in L. collosoma by overexpression of dominant-negative mutated 7SL RNA, a major effect was observed on polytopic membrane proteins but not on signal peptide-containing proteins. This study included two trypanosomatid species, tested various protein substrates, and induced depletion of the SRP pathway by affecting either the levels of SRP binding proteins or that of SRP RNA. Our results demonstrate that, as in bacteria but in contrast to mammalian cells, the trypanosome SRP is mostly essential for the biogenesis of membrane proteins.
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Affiliation(s)
- Yaniv Lustig
- The Mina and Everard Goodman Faculty of Life Sciences, Bar Ilan University, Ramat Gan, Israel
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Dey R, Khan S, Pahari S, Srivastava N, Jadhav M, Saha B. Functional paradox in host–pathogen interaction dictates the fate of parasites. Future Microbiol 2007; 2:425-37. [PMID: 17683278 DOI: 10.2217/17460913.2.4.425] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The interactions between the protozoan parasite Leishmania and host macrophages are complex and involve several paradoxical functions that are meant for protection of the host but exploited by the parasite for its survival. The initial interaction of the parasite surface molecules with the host-cell receptors plays a major role in the final outcome of the disease state. While the interactions between macrophages and a virulent strain of Leishmania trigger a cascade of cell-signaling events leading to immunosuppression, the interaction with an avirulent strain triggers host-protective immune effector functions. Thus, an incisive study on Leishmania–macrophage interactions reveals functional paradoxes that highlight the concept of ‘relativity in parasite virulence’. Using Leishmania infection as a model, we propose that virulence of a pathogen and the resistance (or susceptibility) of a host to the pathogen are relative properties that equate to combinatorial functions of several sets of molecular processes.
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Affiliation(s)
- Ranadhir Dey
- National Centre for Cell Science, Ganeshkhind, Pune, India.
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McConville MJ, de Souza D, Saunders E, Likic VA, Naderer T. Living in a phagolysosome; metabolism of Leishmania amastigotes. Trends Parasitol 2007; 23:368-75. [PMID: 17606406 DOI: 10.1016/j.pt.2007.06.009] [Citation(s) in RCA: 140] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2006] [Revised: 04/26/2007] [Accepted: 06/13/2007] [Indexed: 12/11/2022]
Abstract
Leishmania amastigotes primarily proliferate within macrophages in the mammalian host. Genome-based metabolic reconstructions, combined with biochemical, reverse genetic and mRNA or protein profiling studies are providing new insights into the metabolism of this intracellular stage. We propose that the complex nutritional requirements of amastigotes have contributed to the tropism of these parasites for the amino acid-rich phagolysosome of macrophages. Amastigote metabolism in this compartment is robust because many metabolic mutants are capable of either growing normally or persisting long term in susceptible animals. New approaches for measuring amastigote metabolism in vivo are discussed.
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Affiliation(s)
- Malcolm J McConville
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria 3010, Australia.
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35
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García-Estrada C, Pérez-Pertejo Y, Ordóñez D, Balaña-Fouce R, Reguera RM. Analysis of genetic elements regulating the methionine adenosyltransferase gene in Leishmania infantum. Gene 2007; 389:163-73. [PMID: 17196769 DOI: 10.1016/j.gene.2006.11.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2006] [Revised: 09/07/2006] [Accepted: 11/03/2006] [Indexed: 01/16/2023]
Abstract
Methionine adenosyltransferase (MAT) is an important enzyme for metabolic processes, inasmuch as its product, S-adenosylmethionine (AdoMet), plays a key role in trans-methylation, trans-sulphuration and polyamine synthesis. Our prior studies have shown that the Leishmania infantum genome contains two identical copies of the gene encoding MAT (MAT2 gene), arranged in head-to-tail configuration and alternating with another gene, called LORIEN that contains a zinc-finger motif. Both genes are constitutively expressed throughout the promastigote stage of the parasite cell cycle, and their flanking regions were detected by RT-PCR. Luciferase (luc) reporter assays indicated the presence of regulatory elements within the MAT2 3'UTR and intergenic region, and fragments responsible for such regulation were identified by deletional analysis. By site-directed mutagenesis of the wild-type -42 AG recognized in the trans-splicing of the MAT2 gene, the AG slightly downstream (position -36) was observed to be able to generate the same levels of luc expression, thus suggesting that potentially this gene has alternative spliced leader acceptor sites. The stability of MAT2 and LORIEN transcripts was very similar in both logarithmic and stationary phases. However, cycloheximide (CHX) inhibition of protein synthesis increased MAT2 and LORIEN mRNA levels in the logarithmic phase only, an indication that these genes are regulated in promastigotes at the post-transcriptional level by protein factors that targets both transcripts for degradation. However, during the stationary phase, another CHX-independent factor also led to MAT2 and LORIEN mRNAs degradation, indicating the existence of different mechanisms operating on the post-transcriptional regulation of these two genes.
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Affiliation(s)
- Carlos García-Estrada
- Departamento de Farmacología y Toxicología, Universidad de León, Campus de Vegazana s/n, 24071 León, Spain
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36
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Leifso K, Cohen-Freue G, Dogra N, Murray A, McMaster WR. Genomic and proteomic expression analysis of Leishmania promastigote and amastigote life stages: The Leishmania genome is constitutively expressed. Mol Biochem Parasitol 2007; 152:35-46. [PMID: 17188763 DOI: 10.1016/j.molbiopara.2006.11.009] [Citation(s) in RCA: 158] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2006] [Revised: 11/10/2006] [Accepted: 11/13/2006] [Indexed: 10/23/2022]
Abstract
Leishmania are protozoan parasites that cause a wide spectrum of clinical diseases in humans and are a major public health risk in several countries. Leishmania life cycle consists of an extracellular flagellated promastigote stage within the midgut of a sandfly vector, and a morphological distinct intracellular amastigote stage within macrophages of a mammalian host. This study reports the use of DNA oligonucleotide genome microarrays representing 8160 genes to analyze the mRNA expression profiles of L. major promastigotes and lesion derived amastigotes. Over 94% of the genes were expressed in both life stages. Advanced statistical analysis identified a surprisingly low degree of differential mRNA expression: 1.4% of the total genes in amastigotes and 1.5% in promastigotes. These microarray results demonstrate that the L. major genome is essentially constitutively expressed in both life stages and suggest that Leishmania is constitutively adapted for survival and replication in either the sandfly vector or macrophage host utilizing an appropriate set of genes for each vastly different environment. Quantitative proteomics, using the isotope coded affinity tag (ICAT) technology and mass spectrometry, was used to identify L. infantum promastigote and axenic amastigote differentially expressed proteins. Of the 91 distinct proteins identified, 8% were differentially expressed in the amastigote stage, 20% were differentially expressed in the promastigote stage, and the remaining 72% were considered constitutively expressed. The differential expression was validated by the identification of previously reported stage specific proteins and identified several amastigote and promastigote novel stage specific proteins.
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Affiliation(s)
- Kirk Leifso
- Immunity and Infection Research Centre, Vancouver Coastal Health Research Institute, Canada
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37
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Rodriguez-Contreras D, Feng X, Keeney KM, Archie Bouwer HG, Landfear SM. Phenotypic characterization of a glucose transporter null mutant in Leishmania mexicana. Mol Biochem Parasitol 2007; 153:9-18. [PMID: 17306380 PMCID: PMC2062483 DOI: 10.1016/j.molbiopara.2007.01.010] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2006] [Revised: 12/22/2006] [Accepted: 01/09/2007] [Indexed: 10/23/2022]
Abstract
Glucose is a major source of energy and carbon in promastigotes of Leishmania mexicana, and its uptake is mediated by three glucose transporters whose genes are encoded within a single cluster. A null mutant in which the glucose transporter gene cluster was deleted by homologous gene replacement was generated previously and shown to grow more slowly than wild type promastigotes but not to be viable as amastigotes in primary tissue culture macrophages or in axenic culture. Further phenotypic characterization demonstrates that the null mutant is unable to import glucose, mannose, fructose, or galactose and that each of the three glucose transporter isoforms, LmGT1, LmGT2, and LmGT3, is capable of transporting each of these hexoses. Complementation of the null mutant with each isoform is able to restore growth in each of the four hexoses to wild type levels. Null mutant promastigotes are reduced in size to about 2/3 the volume of wild type parasites. In addition, the null mutants are significantly more sensitive to oxidative stress than their wild type counterparts. These results underscore the importance of glucose transporters in the parasite life cycle and suggest reasons for their non-viability in the disease-causing amastigote stage.
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Affiliation(s)
- Dayana Rodriguez-Contreras
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, Oregon 97239, USA
| | - Xiuhong Feng
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, Oregon 97239, USA
| | - Kristie M. Keeney
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, Oregon 97239, USA
| | - H. G. Archie Bouwer
- Immunology Research, Early A. Chiles Research Institute and Veterans Affairs Medical Center, Portland, Oregon 97239, USA
| | - Scott M. Landfear
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, Oregon 97239, USA
- *Corresponding author. Tel: +1 503 494 2426; fax: +1 503 494 6862 E-mail address: (S.M. Landfear)
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38
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Saxena A, Lahav T, Holland N, Aggarwal G, Anupama A, Huang Y, Volpin H, Myler PJ, Zilberstein D. Analysis of the Leishmania donovani transcriptome reveals an ordered progression of transient and permanent changes in gene expression during differentiation. Mol Biochem Parasitol 2006; 152:53-65. [PMID: 17204342 PMCID: PMC1904838 DOI: 10.1016/j.molbiopara.2006.11.011] [Citation(s) in RCA: 118] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2006] [Revised: 11/18/2006] [Accepted: 11/22/2006] [Indexed: 01/22/2023]
Abstract
Leishmania donovani is an intracellular protozoan parasite that causes kala-azar in humans. During infection the extracellular insect forms (promastigotes) undergo rapid differentiation to intracellular amastigotes that proliferates in phagolysosomes of mammalian macrophages. We used microarray-based expression profiling to investigate the time-course of changes in RNA abundance during promastigote-to-amastigote differentiation in a host-free system that mimics this process. These studies revealed that several hundred genes underwent an ordered progression of transient or permanent up- and down-regulation during differentiation. Genes that were permanently up-regulated in amastigotes were enriched for transporters and surface proteins, but under-represented in genes involved in protein and other metabolism. Most of these changes occurred late in the differentiation process, when morphological differentiation was essentially complete. Down-regulated genes were over-represented in those involved in cell motility, growth and/or maintenance, and these changes generally occurred earlier in the process. Genes that were transiently up- or down-regulated during differentiation included those encoding heat shock proteins, ubiquitin hydrolases, RNA binding proteins, protein kinases, a protein phosphatase, and a histone deacetylase. These results suggest that changes in mRNA abundance may be important in signal transduction, as well as protein and mRNA turnover, during differentiation. In addition to these mRNA changes, other transcripts including one or more rRNAs and snoRNAs, and non-coding RNAs from several telomeres, also showed substantial changes in abundance during the differentiation process. This paper provides the first genome-scale quantitative analysis of gene expression during the transition from promastigotes to amastigotes and demonstrates the utility of the host-free differentiation system.
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Affiliation(s)
- A Saxena
- Seattle Biomedical Research Institute, 307 Westlake Avenue N, Seattle, WA 98109-5219, USA
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39
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Leroux A, Fleming-Canepa X, Aranda A, Maugeri D, Cazzulo JJ, Sánchez MA, Nowicki C. Functional characterization and subcellular localization of the three malate dehydrogenase isozymes in Leishmania spp. Mol Biochem Parasitol 2006; 149:74-85. [PMID: 16750864 DOI: 10.1016/j.molbiopara.2006.04.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2005] [Revised: 04/25/2006] [Accepted: 04/27/2006] [Indexed: 11/19/2022]
Abstract
As part of a study on the malate dehydrogenase isozymes (MDHs) from Trypanosomatids, three different fractions with MDH activity were obtained from crude extracts of Leishmania mexicana promastigotes combining two different chromatographic steps. Gel filtration chromatography in native conditions showed that most of the MDH activity present in the crude extracts eluted in a single peak, which corresponded to a lower apparent molecular mass ( congruent with 57kDa) than the value expected for typical MDHs. To further characterize the leishmanial isozymes, three putative MDH genes, presumably corresponding to the mitochondrial, glycosomal and cytosolic isoforms were amplified by PCR, cloned into bacterial expression vectors, and the recombinant enzymes purified. Digitonin extraction of intact L. mexicana promastigotes and immunofluorescence microscopy of L. major promastigotes confirmed the subcellular compartmentation of each of the three isozymes. Western blot analysis showed that the three MDHs are developmentally regulated. At the protein level, these isozymes are remarkably more abundant in amastigotes than in promastigotes of L. mexicana. Altogether our results demonstrate the presence of three MDH isoforms with slightly distinct biochemical properties and different subcellular localization in Leishmania spp. Presumably the functional and biochemical features of these isozymes reflect the metabolic adaptation to the different nutrient sources these parasites have to face along their life cycle. These results also emphasize the differences among Trypanosomatids in this area of metabolism, since in the case of Trypanosoma brucei the cMDH is the only isoform expressed in bloodstream trypomastigotes, whereas in Trypanosoma cruzi cMDH is absent.
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Affiliation(s)
- Alejandro Leroux
- Instituto de Química y Fisicoquímica Biológica IQUIFIB-CONICET, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junín 956, CP1113 Buenos Aires, Argentina
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40
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Yakovich AJ, Ragone FL, Alfonzo JD, Sackett DL, Werbovetz KA. Leishmania tarentolae: purification and characterization of tubulin and its suitability for antileishmanial drug screening. Exp Parasitol 2006; 114:289-96. [PMID: 16753146 PMCID: PMC1986769 DOI: 10.1016/j.exppara.2006.04.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2006] [Revised: 04/17/2006] [Accepted: 04/24/2006] [Indexed: 12/31/2022]
Abstract
Previously, tubulin has been purified from Leishmania amazonensis and used to identify novel molecules with selective antimitotic activity. However, L. amazonensis is pathogenic and requires a relatively expensive medium for large-scale cultivation. Herein, the purification and characterization of tubulin from the non-pathogenic Leishmania tarentolae is reported, together with the sequence of alpha- and beta-tubulin from this organism. This protein was purified by sonication, diethylaminoethyl-Sepharose chromatography, and one assembly disassembly cycle in 1% overall recovery based on total cellular protein. Leishmania tarentolae tubulin was indistinguishable from the corresponding L. amazonensis protein in terms of binding affinity for dinitroaniline sulfanilamides and sensitivity to assembly inhibition by these compounds. The amino acid sequences derived from the L. tarentolae alpha- and beta-tubulin genes were 99.6 and 99.4% identical to the corresponding amino acid sequences from the Leishmania major Friedlin strain. These results indicate that tubulin from L. tarentolae is suitable for use in drug screening.
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Affiliation(s)
- Adam J. Yakovich
- Division of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, the Ohio State University, Columbus, OH 43210, USA
| | - Frank L. Ragone
- College of Biological Sciences, the Ohio State University, Columbus, OH 43210, USA
| | - Juan D. Alfonzo
- College of Biological Sciences, the Ohio State University, Columbus, OH 43210, USA
| | - Dan L. Sackett
- Laboratory of Integrative and Medical Biophysics, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892 USA
| | - Karl A. Werbovetz
- Division of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, the Ohio State University, Columbus, OH 43210, USA
- * Corresponding author. Tel.: +1 614 292 5499; fax: +1 614 292 2435; E-mail address:
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41
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Rodríguez-Contreras D, Landfear SM. Metabolic changes in glucose transporter-deficient Leishmania mexicana and parasite virulence. J Biol Chem 2006; 281:20068-76. [PMID: 16707495 DOI: 10.1074/jbc.m603265200] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Leishmania mexicana are parasitic protozoa that express a variety of glycoconjugates that play important roles in their biology as well as the storage carbohydrate beta-mannan, which is an essential virulence factor for survival of intracellular amastigote forms in the mammalian host. Glucose transporter null mutants, which are viable as insect form promastigotes but not as amastigotes, do not take up glucose and other hexoses but are still able to synthesize these glycoconjugates and beta-mannan, although at reduced levels. Synthesis of these carbohydrate-containing macromolecules could be accounted for by incorporation of non-carbohydrate precursors into carbohydrates by gluconeogenesis. However, the significantly reduced level of the virulence factor beta-mannan in the glucose transporter null mutants compared with wild-type parasites may contribute to the non-viability of these null mutants in the disease-causing amastigote stage of the life cycle.
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Affiliation(s)
- Dayana Rodríguez-Contreras
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, Oregon 97239, USA
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42
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Holzer TR, McMaster WR, Forney JD. Expression profiling by whole-genome interspecies microarray hybridization reveals differential gene expression in procyclic promastigotes, lesion-derived amastigotes, and axenic amastigotes in Leishmania mexicana. Mol Biochem Parasitol 2006; 146:198-218. [PMID: 16430978 DOI: 10.1016/j.molbiopara.2005.12.009] [Citation(s) in RCA: 134] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2005] [Revised: 11/27/2005] [Accepted: 12/16/2005] [Indexed: 11/22/2022]
Abstract
We examined the Leishmania mexicana transcriptome to identify differentially regulated mRNAs using high-density whole-genome oligonucleotide microarrays designed from the genome data of a closely related species, Leishmania major. Statistical analysis on array hybridization data representing 8156 predicted coding regions revealed 288 genes (3.5% of all genes) whose steady-state mRNA levels meet criteria for differential regulation between promastigotes and lesion-derived amastigotes. Interestingly, sample comparison of promastigotes to axenic amastigotes resulted in only 17 genes (0.2%) that meet the same statistical criteria for differential regulation. The reduced number of regulated genes is a consequence of an increase in the magnitude of the transcript levels in cells under axenic conditions. The expression data for a subset of genes was validated by quantitative PCR. Our studies show that interspecies hybridization on microarrays can be used to analyze closely related protozoan parasites, that axenic culture conditions may alter amastigote transcript abundance, and that there is only a relatively modest change in abundance of a few mRNAs between morphologically distinct promastigote and amastigote cultured cells. Leishmania may represent an alternative paradigm for eukaryotic differentiation with minimal contributions from changes in mRNA abundance.
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Affiliation(s)
- Timothy R Holzer
- Purdue University, Department of Biochemistry, West Lafayette, IN 47907-2063, USA
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43
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Hankins EG, Gillespie JR, Aikenhead K, Buckner FS. Upregulation of sterol C14-demethylase expression in Trypanosoma cruzi treated with sterol biosynthesis inhibitors. Mol Biochem Parasitol 2005; 144:68-75. [PMID: 16165233 DOI: 10.1016/j.molbiopara.2005.08.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2005] [Revised: 08/01/2005] [Accepted: 08/03/2005] [Indexed: 11/26/2022]
Abstract
Infection with the protozoan, Trypanosoma cruzi, is the cause of Chagas disease that occurs widely throughout Latin America. T. cruzi contains sterol biosynthesis enzymes, and produces sterol products similar to those found in fungi. Antifungal drugs that inhibit ergosterol biosynthesis have potent anti-T. cruzi activity in vitro and in animal models. In this report, we describe the effects of sterol biosynthesis inhibitors (simvistatin, zaragosic acid, terbinafine, a lanosterol synthase inhibitor, ketoconazole, and tridemorph) on the regulation of two sterol biosynthesis genes and their protein products. Culturing T. cruzi in the presence of the lanosterol synthase inhibitor, terbinafine, or ketoconazole increased mRNA levels of the sterol C14-demethylase gene approximately 7-12-fold. The sterol C14-demethylase protein levels were also elevated. The effects of the sterol biosynthesis inhibitors on hydroxymethylglutaryl-CoA reductase expression were minimal. Control of the upregulation of sterol C14-demethylase appears to be mediated through the 3'-untranslated region of the gene. The findings demonstrate that T. cruzi can specifically regulate gene expression in response to derangements in its cellular functions.
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Affiliation(s)
- Eleanor G Hankins
- Department of Medicine, University of Washington, Seattle, WA 98195, USA
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44
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Purdy JE, Donelson JE, Wilson ME. Regulation of genes encoding the major surface protease of Leishmania chagasi via mRNA stability. Mol Biochem Parasitol 2005; 142:88-97. [PMID: 15876463 DOI: 10.1016/j.molbiopara.2005.03.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2004] [Revised: 03/16/2005] [Accepted: 03/23/2005] [Indexed: 01/08/2023]
Abstract
The intercoding regions between many Leishmania sp. genes regulate their mRNA expression. The MSPL mRNA, encoding a subclass of the major surface protease (MSP) of Leishmania chagasi, increases in abundance, when protein synthesis is arrested, while alpha-tubulin (alpha-TUB) mRNA and most other mRNAs do not. We found that the intercoding region between MSPL-coding regions, when cloned downstream of the beta-galactosidase reporter gene (beta-GAL), caused beta-GAL mRNA to increase 8- to 10-fold after inhibiting protein synthesis with cycloheximide. Stable L. chagasi transfectants containing hybrid MSPL/alpha-TUB intercoding regions cloned downstream of beta-GAL were made. The alpha-TUB intercoding region induced high-level baseline beta-GAL mRNA that increased only 1.3-fold after incubation with cycloheximide. In contrast, the MSPL intercoding region, as well as constructs containing nucleotides 303-505 from the MSPL 3'UTR, caused steady-state beta-GAL mRNA levels in the absence of cycloheximide that were approximately 10% of alpha-TUB constructs. These levels increased between 4.4- and 13.2-fold after cycloheximide was added. Constructs containing half of this region (303-394 or 395-505) produced intermediate levels of beta-GAL mRNA and intermediate levels of cycloheximide induction. The kinetics of cycloheximide induction of beta-GAL mRNA was similar with region 303-505 constructs as with constructs bearing the entire endogenous MSPL intercoding region. Furthermore, region 303-505 increased reporter mRNA abundance after cycloheximide by increasing mRNA half-life. Hence, we have identified a 202-nucleotide region within the MSPL 3'UTR that is in part responsible for cycloheximide induction. We hypothesize that this region may interact with labile regulatory protein factor(s).
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Affiliation(s)
- Jay E Purdy
- Department of Internal Medicine, University of Iowa, Iowa City, IA 52242, USA.
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45
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Rochette A, McNicoll F, Girard J, Breton M, Leblanc E, Bergeron MG, Papadopoulou B. Characterization and developmental gene regulation of a large gene family encoding amastin surface proteins in Leishmania spp. Mol Biochem Parasitol 2005; 140:205-20. [PMID: 15760660 DOI: 10.1016/j.molbiopara.2005.01.006] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2004] [Accepted: 01/14/2005] [Indexed: 11/23/2022]
Abstract
The ability of Leishmania amastigotes to survive within the drastic environmental changes encountered in the phagolysosomes of mammalian macrophages is heavily dependent on the developmental regulation of a variety of genes. The identification of genes that are expressed preferentially in the mammalian stage of the parasite should increase our understanding of the molecular mechanisms regulating stage-specific gene expression and of the determinants that control its intracellular survival and contribute to its pathogenesis. We report here detailed sequence characterization and structural organization of the amastin gene family in Leishmania major and Leishmania infantum and the study of their developmental gene regulation throughout the parasite's life cycle. Amastin surface proteins represent the largest developmentally regulated gene family reported so far in Leishmania comprising up to 45 members. All the members of the amastin gene family in both Leishmania and Trypanosoma species share a similar structural organization and contain a highly conserved 11 amino acid extracellular domain, which is unique to amastin proteins. The majority of the amastin gene homologs are specifically expressed in the amastigote stage of the parasite. Three distinct RNA elements were identified in the 3'-untranslated regions (3'UTR) of the amastin transcripts. The majority of these transcripts contain a conserved 450 nt cis-acting 3'UTR element shown previously to regulate stage-specific gene expression at the level of translation, which suggests that several amastin homologs may be regulated by a similar mechanism of translational control inside the macrophage. These findings further highlight the unique features of gene expression control in Leishmania.
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Affiliation(s)
- Annie Rochette
- Infectious Diseases Research Center, RC-709, CHUL Research Center and Department of Medical Biology, Faculty of Medicine, Laval University, 2705 Laurier Blvd., Ste-Foy (QC), Que., Canada G1V 4G2
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Uzcategui NL, Figarella K, Camacho N, Ponte-Sucre A. Substrate preferences and glucose uptake in glibenclamide-resistant Leishmania parasites. Comp Biochem Physiol C Toxicol Pharmacol 2005; 140:395-402. [PMID: 15886061 DOI: 10.1016/j.cca.2005.04.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2004] [Revised: 03/28/2005] [Accepted: 04/01/2005] [Indexed: 11/23/2022]
Abstract
Several drug-resistant mammalian cell types exhibit increased glycolytic rates, preferential synthesis of ATP through oxidative phosphorylation, and altered glucose transport. Herein we analyzed the influence of parasite growth phase on energy substrate uptake and use in a Leishmania strain [NR(Gr)] selected for resistance against glibenclamide. Glibenclamide is an ABC-transporter blocker which modulates the function of glucose transporters in some mammalian cells. Our results demonstrate for the first time that compared to glibenclamide-sensitive Leishmania, exponential phase glibenclamide-resistant parasites exhibit decreased use of glucose as energy substrate, decreased glucose uptake and decreased glucose transporter expression. However, compared to glibenclamide-sensitive cells, stationary phase resistant parasites display an increased use of amino acids as energy substrate and an increased activity of the enzymes hexokinase, phosphoglucose isomerase, and especially NAD(+)-linked glutamate dehydrogenase. These results suggest that drug resistance in Leishmania involves a metabolic adaptation that promotes a stage dependent modulation of energy substrate uptake and use as a physiological response to the challenge imposed by drug pressure.
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Affiliation(s)
- Nestor Luis Uzcategui
- Laboratorio de Fisiología Molecular, Instituto de Medicina Experimental, Facultad de Medicina, Universidad Central de Venezuela, Caracas, Venezuela
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Le Roch KG, Johnson JR, Florens L, Zhou Y, Santrosyan A, Grainger M, Yan SF, Williamson KC, Holder AA, Carucci DJ, Yates JR, Winzeler EA. Global analysis of transcript and protein levels across the Plasmodium falciparum life cycle. Genome Res 2005; 14:2308-18. [PMID: 15520293 PMCID: PMC525690 DOI: 10.1101/gr.2523904] [Citation(s) in RCA: 336] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
To investigate the role of post-transcriptional controls in the regulation of protein expression for the malaria parasite, Plasmodium falciparum, we have compared mRNA transcript and protein abundance levels for seven different stages of the parasite life cycle. A moderately high positive relationship between mRNA and protein abundance was observed for these stages; the most common discrepancy was a delay between mRNA and protein accumulation. Potentially post-transcriptionally regulated genes are identified, and families of functionally related genes were observed to share similar patterns of mRNA and protein accumulation.
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Affiliation(s)
- Karine G Le Roch
- Department of Cell Biology ICND202, the Scripps Research Institute, La Jolla, California 92037, USA
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Nasser MIA, Landfear SM. Sequences required for the flagellar targeting of an integral membrane protein. Mol Biochem Parasitol 2004; 135:89-100. [PMID: 15287590 DOI: 10.1016/j.molbiopara.2004.01.009] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Previous studies have established that the ISO1 glucose transporter of Leishmania enriettii resides primarily in the flagellar membrane, whereas the ISO2 glucose transporter is located in the pellicular plasma membrane surrounding the cell body. This pronounced difference in subcellular targeting is conferred by the NH2-terminal domain of the transporters, since this is the only region of the two permeases that differs in sequence. Analysis of the 130 residue NH2-terminal domain of ISO1 using multiple terminal deletion mutants and various internal deletion mutants established that a sequence located between amino acids 84 and 100 of this domain is required for flagellar trafficking. In addition, chimeras between ISO1 and ISO2 indicated that the region between residues 110 and 118 of ISO1 is also required for flagellar targeting. These results imply that flagellar targeting information for this integral membrane protein does not constitute a simple linear sequence of amino acids but is at least bipartite in structure.
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Affiliation(s)
- Marina Ignatushchenko Abdel Nasser
- Department of Molecular Microbiology and Immunology, Oregon Health and Science University, 3181 SW Sam Jackson Park Road, Portland, OR 97239-3098, USA
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Maugeri DA, Cazzulo JJ, Burchmore RJS, Barrett MP, Ogbunude POJ. Pentose phosphate metabolism in Leishmania mexicana. Mol Biochem Parasitol 2003; 130:117-25. [PMID: 12946848 DOI: 10.1016/s0166-6851(03)00173-7] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The metabolism of pentose phosphates was studied in Leishmania mexicana promastigotes. Each of the enzymes of the classical pentose phosphate pathway (PPP) has been identified and specific activities measured. Functioning of the PPP was demonstrated in non-growing cells by measuring the evolution of 14CO2 from [1-14C]D-glucose and [6-14C]D-glucose under normal conditions and also under selective stimulation of the PPP by exposure to methylene blue. The proportion of glucose which passes through the PPP increases in the latter condition, thus suggesting a protective role against oxidant stress. The incorporation into nucleic acids of ribose 5-phosphate provided via either glucose or free ribose was also determined. Results indicate that the PPP enables glucose to serve as a source of ribose 5-phosphate in nucleotide biosynthesis. Moreover, free ribose is incorporated efficiently, implying the presence of a ribose uptake system and also of ribokinase. Ribose was shown to be accumulated by a carrier mediated process in L. mexicana promastigotes and ribokinase activity was also measured in these cells.
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Affiliation(s)
- Dante Abel Maugeri
- Instituto de Investigaciones Biotecnologicas, Universidad Nacional de General San Martin, 1650 San Martin, Buenos Aires, Argentina
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Saxena A, Worthey EA, Yan S, Leland A, Stuart KD, Myler PJ. Evaluation of differential gene expression in Leishmania major Friedlin procyclics and metacyclics using DNA microarray analysis. Mol Biochem Parasitol 2003; 129:103-14. [PMID: 12798511 DOI: 10.1016/s0166-6851(03)00100-2] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The various Leishmania species are flagellated protozoans, responsible for a wide spectrum of human diseases. The sequence of the L. major genome is nearing completion and a large proportion of the identified genes have yet to be ascribed functions. DNA microarrays containing PCR-amplified DNA from a random amplified genomic library of L. major Friedlin (LmjF) [Mol. Biochem. Parasitol. 113 (2001) 337] were hybridized with fluorescent probes made from L. major Friedlin RNA from five time-points during differentiation from procyclics to metacyclics. The data were normalized for background and probe intensity and the relative abundance of RNA for each spot was calculated. Almost 15% (1387/9282) of the DNAs showed statistically significant (P<0.01) changes in expression (1.1-5-fold) during the transition, with 1.16% (108) showing up-regulation at two or more time-points and 0.14% (13) showing down-regulation. Northern blot analyses of selected genes confirmed these results. These studies confirmed the stage-specific expression of several known genes, as well as identifying a number of novel genes that are up-regulated in either procyclics or metacyclics.
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Affiliation(s)
- Alka Saxena
- Department of Pathobiology, Seattle Biomedical Research Institute, 4 Nickerson Street, Seattle, WA 98109-1651, USA
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