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Pardo-Rodriguez D, Lasso P, Santamaría-Torres M, Cala MP, Puerta CJ, Méndez Arteaga JJ, Robles J, Cuervo C. Clethra fimbriata hexanic extract triggers alteration in the energy metabolism in epimastigotes of Trypanosoma cruzi. Front Mol Biosci 2023; 10:1206074. [PMID: 37818099 PMCID: PMC10561390 DOI: 10.3389/fmolb.2023.1206074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Accepted: 09/13/2023] [Indexed: 10/12/2023] Open
Abstract
Chagas disease (ChD), caused by Trypanosoma cruzi, is endemic in American countries and an estimated 8 million people worldwide are chronically infected. Currently, only two drugs are available for therapeutic use against T. cruzi and their use is controversial due to several disadvantages associated with side effects and low compliance with treatment. Therefore, there is a need to search for new tripanocidal agents. Natural products have been considered a potential innovative source of effective and selective agents for drug development to treat T. cruzi infection. Recently, our research group showed that hexanic extract from Clethra fimbriata (CFHEX) exhibits anti-parasitic activity against all stages of T. cruzi parasite, being apoptosis the main cell death mechanism in both epimastigotes and trypomastigotes stages. With the aim of deepening the understanding of the mechanisms of death induced by CFHEX, the metabolic alterations elicited after treatment using a multiplatform metabolomics analysis (RP/HILIC-LC-QTOF-MS and GC-QTOF-MS) were performed. A total of 154 altered compounds were found significant in the treated parasites corresponding to amino acids (Arginine, threonine, cysteine, methionine, glycine, valine, proline, isoleucine, alanine, leucine, glutamic acid, and serine), fatty acids (stearic acid), glycerophospholipids (phosphatidylcholine, phosphatidylethanolamine and phosphatidylserine), sulfur compounds (trypanothione) and carboxylic acids (pyruvate and phosphoenolpyruvate). The most affected metabolic pathways were mainly related to energy metabolism, which was found to be decrease during the evaluated treatment time. Further, exogenous compounds of the triterpene type (betulinic, ursolic and pomolic acid) previously described in C. fimbriata were found inside the treated parasites. Our findings suggest that triterpene-type compounds may contribute to the activity of CFHEX by altering essential processes in the parasite.
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Affiliation(s)
- Daniel Pardo-Rodriguez
- Grupo de Enfermedades Infecciosas, Pontificia Universidad Javeriana, Bogotá, Colombia
- Grupo de Fitoquímica, Pontificia Universidad Javeriana, Bogotá, Colombia
- Grupo de Productos Naturales, Universidad del Tolima, Tolima, Colombia
- Metabolomics Core Facility—MetCore, Vice-Presidency for Research, Universidad de los Andes, Bogotá, Colombia
| | - Paola Lasso
- Grupo de Inmunobiología y Biología Celular, Pontificia Universidad Javeriana, Bogotá, Colombia
| | - Mary Santamaría-Torres
- Metabolomics Core Facility—MetCore, Vice-Presidency for Research, Universidad de los Andes, Bogotá, Colombia
| | - Mónica P. Cala
- Metabolomics Core Facility—MetCore, Vice-Presidency for Research, Universidad de los Andes, Bogotá, Colombia
| | - Concepción J. Puerta
- Grupo de Enfermedades Infecciosas, Pontificia Universidad Javeriana, Bogotá, Colombia
| | | | - Jorge Robles
- Grupo de Fitoquímica, Pontificia Universidad Javeriana, Bogotá, Colombia
| | - Claudia Cuervo
- Grupo de Enfermedades Infecciosas, Pontificia Universidad Javeriana, Bogotá, Colombia
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Deveci G, Kamil M, Kina U, Temel BA, Aly ASI. Genetic disruption of nucleoside transporter 4 reveals its critical roles in malaria parasite sporozoite functions. Pathog Glob Health 2023; 117:284-292. [PMID: 36003062 PMCID: PMC10081079 DOI: 10.1080/20477724.2022.2112880] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2022] Open
Abstract
All protozoan parasites are lacking the pathway to synthesize purines de novo and therefore they depend on their host cells to provide purines. A number of highly conserved nucleoside transporter (NT) proteins are encoded in malaria parasite genomes, of which NT1 is characterized in Plasmodium falciparum and P. yoelii as a plasma membrane protein that is responsible for salvage of purines from the host, and NT2 is an endoplasmic membrane NT protein. Whereas NT3 is only present in primate malaria parasites, little is known about NT4, which is conserved in all malaria parasite species. Herein, we targeted NT4 gene for deletion in P. berghei. NT4 knockout parasites developed normally as blood stages, ookinetes and formed oocysts with sporozoites compared with wild-type (WT) P. berghei ANKA parasites. However, nt4(-) sporozoites showed significantly decreased egress from oocysts to hemolymph, significant reduction of colonization of the salivary glands, and complete abolishment of infection of the mammalian host by salivary gland and hemolymph sporozoites. Therefore, we identify NT4 as a NT that is important, not for replication and growth, but for sporozoite infectivity functions.
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Affiliation(s)
- Gozde Deveci
- Aly Lab, Beykoz Institute of Life Sciences and Biotechnology, Bezmialem Vakif University, Istanbul, Turkey
- Department of Biotechnology, Institute of Health Sciences, Bezmialem Vakif University, Istanbul, Turkey
| | - Mohd Kamil
- Aly Lab, Beykoz Institute of Life Sciences and Biotechnology, Bezmialem Vakif University, Istanbul, Turkey
| | - Umit Kina
- Aly Lab, Beykoz Institute of Life Sciences and Biotechnology, Bezmialem Vakif University, Istanbul, Turkey
- Department of Biotechnology, Institute of Health Sciences, Bezmialem Vakif University, Istanbul, Turkey
| | - Binnur Aydogan Temel
- Department of Biotechnology, Institute of Health Sciences, Bezmialem Vakif University, Istanbul, Turkey
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Bezmialem Vakif University, Istanbul, Turkey
| | - Ahmed S. I. Aly
- Aly Lab, Beykoz Institute of Life Sciences and Biotechnology, Bezmialem Vakif University, Istanbul, Turkey
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Majumder N, Banerjee A, Saha S. A review on new natural and synthetic anti-leishmanial chemotherapeutic agents and current perspective of treatment approaches. Acta Trop 2023; 240:106846. [PMID: 36720335 DOI: 10.1016/j.actatropica.2023.106846] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 01/23/2023] [Accepted: 01/26/2023] [Indexed: 01/31/2023]
Abstract
Leishmaniases are considered among the most neglected yet dangerous parasitic diseases worldwide. According to the recent WHO report (Weekly Epidemiological Record, Sep, 2021), 200 countries and territories reported leishmanises cases in 2020; of which 89 (45%) for CL, and 79 (40%) for VL were endemic. Indian subcontinent (India, Bangladesh and Nepal), one of the three eco-epidemiological hotspots of VL, currently reported 18% of the total cases of VL worldwide. Eastern Mediterranean region and the Region of the Americas together reported >90% of the new CL cases, of which >80% were from Afghanistan, Algeria, Brazil, Colombia, Iraq, Pakistan and the Syrian Arab Republic. While considering the current therapeutic options, conventional anti-leishmanial drugs have long been proved to be toxic and/or expensive and have resulted in extensive drug resistance in India. Recent searches for novel anti-leishmanial drugs have led to find out the prime cellular targets and metabolic pathways to bridge the gap between the known facts and unexplored data. Cutting edge knowledge based drug designing has simplified the search for novel molecules with leishmanicidal efficacy by identifying ligand-receptor interactions and has accelerated the cost effective primary discovery of molecules through computational validation against Leishmaniases. This review focuses on the limitations of conventional drugs, and discusses the chemotherapeutic potential of many novel natural and synthetic anti-leishmanial agents reported since the last decade. It is also interpreted that some of the reported molecules might be tested singly or as a part of combinatorial therapy on pre-clinical and clinical level.
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Affiliation(s)
- Nilanjana Majumder
- Department of Biotechnology, Visva-Bharati, Santiniketan, 731235 West Bengal, India
| | - Antara Banerjee
- Department of Zoology, Bangabasi College, 19 Rajkumar Chakraborty Sarani, Kolkata, 700009 West Bengal, India
| | - Samiran Saha
- Department of Biotechnology, Visva-Bharati, Santiniketan, 731235 West Bengal, India.
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Wang C, Yu L, Zhang J, Zhou Y, Sun B, Xiao Q, Zhang M, Liu H, Li J, Li J, Luo Y, Xu J, Lian Z, Lin J, Wang X, Zhang P, Guo L, Ren R, Deng D. Structural basis of the substrate recognition and inhibition mechanism of Plasmodium falciparum nucleoside transporter PfENT1. Nat Commun 2023; 14:1727. [PMID: 36977719 PMCID: PMC10050424 DOI: 10.1038/s41467-023-37411-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Accepted: 03/16/2023] [Indexed: 03/30/2023] Open
Abstract
By lacking de novo purine biosynthesis enzymes, Plasmodium falciparum requires purine nucleoside uptake from host cells. The indispensable nucleoside transporter ENT1 of P. falciparum facilitates nucleoside uptake in the asexual blood stage. Specific inhibitors of PfENT1 prevent the proliferation of P. falciparum at submicromolar concentrations. However, the substrate recognition and inhibitory mechanism of PfENT1 are still elusive. Here, we report cryo-EM structures of PfENT1 in apo, inosine-bound, and inhibitor-bound states. Together with in vitro binding and uptake assays, we identify that inosine is the primary substrate of PfENT1 and that the inosine-binding site is located in the central cavity of PfENT1. The endofacial inhibitor GSK4 occupies the orthosteric site of PfENT1 and explores the allosteric site to block the conformational change of PfENT1. Furthermore, we propose a general "rocker switch" alternating access cycle for ENT transporters. Understanding the substrate recognition and inhibitory mechanisms of PfENT1 will greatly facilitate future efforts in the rational design of antimalarial drugs.
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Affiliation(s)
- Chen Wang
- Department of Obstetrics, Key Laboratory of Birth Defects and Related Disease of Women and Children of MOE, State Key Laboratory of Biotherapy, West China Second Hospital, Sichuan University, Chengdu, 610041, China
- Shanghai Key Laboratory of Metabolic Remodeling and Health, Institute of Metabolism and Integrative Biology, Fudan University, Shanghai, 200438, China
| | - Leiye Yu
- Shanghai Key Laboratory of Metabolic Remodeling and Health, Institute of Metabolism and Integrative Biology, Fudan University, Shanghai, 200438, China
- Warshal Institute of Computational Biology, School of Life and Health Sciences, the Chinese University of Hong Kong, Shenzhen, Guangdong, 518172, China
| | - Jiying Zhang
- Department of Obstetrics, Key Laboratory of Birth Defects and Related Disease of Women and Children of MOE, State Key Laboratory of Biotherapy, West China Second Hospital, Sichuan University, Chengdu, 610041, China
| | - Yanxia Zhou
- Department of Obstetrics, Key Laboratory of Birth Defects and Related Disease of Women and Children of MOE, State Key Laboratory of Biotherapy, West China Second Hospital, Sichuan University, Chengdu, 610041, China
| | - Bo Sun
- Shanghai Synchrotron Radiation Facility, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai, 201204, China
| | - Qingjie Xiao
- Shanghai Synchrotron Radiation Facility, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai, 201204, China
| | - Minhua Zhang
- National Key Laboratory of Plant Molecular Genetics, Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, 200032, China
| | - Huayi Liu
- Department of Obstetrics, Key Laboratory of Birth Defects and Related Disease of Women and Children of MOE, State Key Laboratory of Biotherapy, West China Second Hospital, Sichuan University, Chengdu, 610041, China
| | - Jinhong Li
- Department of Obstetrics, Key Laboratory of Birth Defects and Related Disease of Women and Children of MOE, State Key Laboratory of Biotherapy, West China Second Hospital, Sichuan University, Chengdu, 610041, China
| | - Jialu Li
- Department of Obstetrics, Key Laboratory of Birth Defects and Related Disease of Women and Children of MOE, State Key Laboratory of Biotherapy, West China Second Hospital, Sichuan University, Chengdu, 610041, China
| | - Yunzi Luo
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering of MOE, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China
| | - Jie Xu
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Zhong Lian
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Jingwen Lin
- Department of Obstetrics, Key Laboratory of Birth Defects and Related Disease of Women and Children of MOE, State Key Laboratory of Biotherapy, West China Second Hospital, Sichuan University, Chengdu, 610041, China
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Xiang Wang
- Department of Obstetrics, Key Laboratory of Birth Defects and Related Disease of Women and Children of MOE, State Key Laboratory of Biotherapy, West China Second Hospital, Sichuan University, Chengdu, 610041, China
| | - Peng Zhang
- National Key Laboratory of Plant Molecular Genetics, Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, 200032, China
| | - Li Guo
- Department of Obstetrics, Key Laboratory of Birth Defects and Related Disease of Women and Children of MOE, State Key Laboratory of Biotherapy, West China Second Hospital, Sichuan University, Chengdu, 610041, China.
| | - Ruobing Ren
- Shanghai Key Laboratory of Metabolic Remodeling and Health, Institute of Metabolism and Integrative Biology, Fudan University, Shanghai, 200438, China.
- Shanghai Qi Zhi Institute, Shanghai, 200030, China.
| | - Dong Deng
- Department of Obstetrics, Key Laboratory of Birth Defects and Related Disease of Women and Children of MOE, State Key Laboratory of Biotherapy, West China Second Hospital, Sichuan University, Chengdu, 610041, China.
- NHC key Laboratory of Chronobiology, Sichuan University, Chengdu, 610041, China.
- Development and Related Diseases of Women and Children Key Laboratory of Sichuan Province, Sichuan University, Chengdu, 610041, China.
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Smircich P, Pérez-Díaz L, Hernández F, Duhagon MA, Garat B. Transcriptomic analysis of the adaptation to prolonged starvation of the insect-dwelling Trypanosoma cruzi epimastigotes. Front Cell Infect Microbiol 2023; 13:1138456. [PMID: 37091675 PMCID: PMC10117895 DOI: 10.3389/fcimb.2023.1138456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 03/20/2023] [Indexed: 04/25/2023] Open
Abstract
Trypanosoma cruzi is a digenetic unicellular parasite that alternates between a blood-sucking insect and a mammalian, host causing Chagas disease or American trypanosomiasis. In the insect gut, the parasite differentiates from the non-replicative trypomastigote forms that arrive upon blood ingestion to the non-infective replicative epimastigote forms. Epimastigotes develop into infective non-replicative metacyclic trypomastigotes in the rectum and are delivered via the feces. In addition to these parasite stages, transitional forms have been reported. The insect-feeding behavior, characterized by few meals of large blood amounts followed by long periods of starvation, impacts the parasite population density and differentiation, increasing the transitional forms while diminishing both epimastigotes and metacyclic trypomastigotes. To understand the molecular changes caused by nutritional restrictions in the insect host, mid-exponentially growing axenic epimastigotes were cultured for more than 30 days without nutrient supplementation (prolonged starvation). We found that the parasite population in the stationary phase maintains a long period characterized by a total RNA content three times smaller than that of exponentially growing epimastigotes and a distinctive transcriptomic profile. Among the transcriptomic changes induced by nutrient restriction, we found differentially expressed genes related to managing protein quality or content, the reported switch from glucose to amino acid consumption, redox challenge, and surface proteins. The contractile vacuole and reservosomes appeared as cellular components enriched when ontology term overrepresentation analysis was carried out, highlighting the roles of these organelles in starving conditions possibly related to their functions in regulating cell volume and osmoregulation as well as metabolic homeostasis. Consistent with the quiescent status derived from nutrient restriction, genes related to DNA metabolism are regulated during the stationary phase. In addition, we observed differentially expressed genes related to the unique parasite mitochondria. Finally, our study identifies gene expression changes that characterize transitional parasite forms enriched by nutrient restriction. The analysis of the here-disclosed regulated genes and metabolic pathways aims to contribute to the understanding of the molecular changes that this unicellular parasite undergoes in the insect vector.
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Affiliation(s)
- Pablo Smircich
- Sección Genómica Funcional, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
- Laboratorio de Bioinformática, Departamento de Genómica, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay
- *Correspondence: Beatriz Garat, ; Pablo Smircich,
| | - Leticia Pérez-Díaz
- Sección Genómica Funcional, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
| | - Fabricio Hernández
- Sección Genómica Funcional, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
| | - María Ana Duhagon
- Sección Genómica Funcional, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
- Departamento de Genética, Facultad de Medicina Universidad de la República, Montevideo, Uruguay
| | - Beatriz Garat
- Sección Genómica Funcional, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
- *Correspondence: Beatriz Garat, ; Pablo Smircich,
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6
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Soni M, Pratap JV. Development of Novel Anti-Leishmanials: The Case for Structure-Based Approaches. Pathogens 2022; 11:pathogens11080950. [PMID: 36015070 PMCID: PMC9414883 DOI: 10.3390/pathogens11080950] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 08/16/2022] [Accepted: 08/17/2022] [Indexed: 11/16/2022] Open
Abstract
The neglected tropical disease (NTD) leishmaniasis is the collective name given to a diverse group of illnesses caused by ~20 species belonging to the genus Leishmania, a majority of which are vector borne and associated with complex life cycles that cause immense health, social, and economic burdens locally, but individually are not a major global health priority. Therapeutic approaches against leishmaniasis have various inadequacies including drug resistance and a lack of effective control and eradication of the disease spread. Therefore, the development of a rationale-driven, target based approaches towards novel therapeutics against leishmaniasis is an emergent need. The utilization of Artificial Intelligence/Machine Learning methods, which have made significant advances in drug discovery applications, would benefit the discovery process. In this review, following a summary of the disease epidemiology and available therapies, we consider three important leishmanial metabolic pathways that can be attractive targets for a structure-based drug discovery approach towards the development of novel anti-leishmanials. The folate biosynthesis pathway is critical, as Leishmania is auxotrophic for folates that are essential in many metabolic pathways. Leishmania can not synthesize purines de novo, and salvage them from the host, making the purine salvage pathway an attractive target for novel therapeutics. Leishmania also possesses an organelle glycosome, evolutionarily related to peroxisomes of higher eukaryotes, which is essential for the survival of the parasite. Research towards therapeutics is underway against enzymes from the first two pathways, while the third is as yet unexplored.
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Affiliation(s)
- Mohini Soni
- Biochemistry and Structural Biology Division, CSIR-Central Drug Research Institute, Sector-10, Jankipuram Extension, Sitapur Road, Lucknow 226031, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - J. Venkatesh Pratap
- Biochemistry and Structural Biology Division, CSIR-Central Drug Research Institute, Sector-10, Jankipuram Extension, Sitapur Road, Lucknow 226031, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
- Correspondence:
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7
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Rico-Jiménez M, Ceballos-Pérez G, Gómez-Liñán C, Estévez AM. An RNA-binding protein complex regulates the purine-dependent expression of a nucleobase transporter in trypanosomes. Nucleic Acids Res 2021; 49:3814-3825. [PMID: 33744953 PMCID: PMC8053114 DOI: 10.1093/nar/gkab181] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2020] [Revised: 03/02/2021] [Accepted: 03/04/2021] [Indexed: 12/13/2022] Open
Abstract
Post-transcriptional regulation of gene expression is particularly important in trypanosomatid protozoa. RNA-binding proteins (RBPs) regulate mRNA stability and translation, yet information about how RBPs are able to link environmental cues to post-transcriptional control is scarce. In Trypanosoma brucei, we have previously characterized a short RNA stem-loop cis-element (PuRE, Purine Responsive Element) within the 3'-UTR of the NT8 nucleobase transporter mRNA that is necessary and sufficient to confer a strong repression of gene expression in response to purines. In this study, we have identified a protein complex composed of two RNA-binding proteins (PuREBP1 and PuREBP2) that binds to the PuRE in vitro and to NT8 mRNA in vivo. Depletion of PuREBP1 by RNA interference results in the upregulation of just NT8 and the mRNAs encoding the amino acid transporter AATP6 paralogues. Moreover, we found that the PuREBP1/2 complex is associated with only a handful of mRNAs, and that it is responsible for the observed purine-dependent regulation of NT8 expression.
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Affiliation(s)
- Miriam Rico-Jiménez
- Instituto de Parasitología y Biomedicina 'López-Neyra', IPBLN-CSIC, Parque Tecnológico de Ciencias de la Salud, Avda. del Conocimiento 17, 18016 Armilla, Granada, Spain
| | - Gloria Ceballos-Pérez
- Instituto de Parasitología y Biomedicina 'López-Neyra', IPBLN-CSIC, Parque Tecnológico de Ciencias de la Salud, Avda. del Conocimiento 17, 18016 Armilla, Granada, Spain
| | - Claudia Gómez-Liñán
- Instituto de Parasitología y Biomedicina 'López-Neyra', IPBLN-CSIC, Parque Tecnológico de Ciencias de la Salud, Avda. del Conocimiento 17, 18016 Armilla, Granada, Spain
| | - Antonio M Estévez
- Instituto de Parasitología y Biomedicina 'López-Neyra', IPBLN-CSIC, Parque Tecnológico de Ciencias de la Salud, Avda. del Conocimiento 17, 18016 Armilla, Granada, Spain
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8
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Nadaf AQA, Najare MS, Garbhagudi M, Mantur S, Sunagar MG, Gaonkar S, Joshi S, Khazi IAM. Synthesis of 6‐[4‐(4‐Propoxyphenyl)piperazin‐1‐yl]‐9
H
‐purine Derivatives as Antimycobacterial and Antifungal Agents:
In Vitro
Evaluation and
In Silico
Study. Chem Biodivers 2020; 17:e2000053. [DOI: 10.1002/cbdv.202000053] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Accepted: 03/12/2020] [Indexed: 11/07/2022]
Affiliation(s)
| | - Mahesh S. Najare
- Department of ChemistryKarnatak University Dharwad 580003 Karnataka India
| | | | - Shivaraj Mantur
- Department of ChemistryKarnatak University Dharwad 580003 Karnataka India
| | | | - Supreet Gaonkar
- Department of ChemistryKarnatak University Dharwad 580003 Karnataka India
| | - Shrinivas Joshi
- Novel Drug Design and Discovery LaboratoryDepartment of Pharmaceutical ChemistryS.E.T.'s College of Pharmacy, Sangolli Rayanna Nagar Dharwad 580002 Karnataka India
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9
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Doukas A, Karena E, Botou M, Papakostas K, Papadaki A, Tziouvara O, Xingi E, Frillingos S, Boleti H. Heterologous expression of the mammalian sodium-nucleobase transporter rSNBT1 in Leishmania tarentolae. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2019; 1861:1546-1557. [PMID: 31283918 DOI: 10.1016/j.bbamem.2019.07.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 06/26/2019] [Accepted: 07/02/2019] [Indexed: 12/13/2022]
Abstract
Recombinant expression systems for mammalian membrane transport proteins are often limited by insufficient yields to support structural studies, inadequate post-translational processing and problems related with improper membrane targeting or cytotoxicity. Use of alternative expression systems and optimization of expression/purification protocols are constantly needed. In this work, we explore the applicability of the laboratory strain LEXSY of the ancient eukaryotic microorganism Leishmania tarentolae as a new expression system for mammalian nucleobase permeases of the NAT/NCS2 (Nucleobase-Ascorbate Transporter/Nucleobase-Cation Symporter-2) family. We achieved the heterologous expression of the purine-pyrimidine permease rSNBT1 from Rattus norvegicus (tagged at C-terminus with a red fluorescent protein), as confirmed by confocal microscopy and biochemical analysis of the subcellular fractions enriched in membrane proteins. The cDNA of rSNBT1 has been subcloned in a pLEXSY-sat-mrfp1vector and used to generate transgenic L. tarentolae-rsnbt1-mrfp1 strains carrying the pLEXSY-sat-rsnbt1-mrfp1 plasmid either episomally or integrated in the chromosomal DNA. The chimeric transporter rSNBT1-mRFP1 is targeted to the ER and the plasma membrane of the L. tarentolae promastigotes. The transgenic strains are capable of transporting nucleobases that are substrates of rSNBT1 but also of the endogenous L. tarentolae nucleoside/nucleobase transporters. A dipyridamole-resistant Na+-dependent fraction of uptake is attributed to the exogenously expressed rSNBT1.
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Affiliation(s)
- Anargyros Doukas
- Intracellular Parasitism Group, Microbiology Department, Hellenic Pasteur Institute, Vas. Sofias 127, Athens 11521, Greece
| | - Ekaterini Karena
- Laboratory of Biological Chemistry, Department of Medicine, University of Ioannina, Greece
| | - Maria Botou
- Laboratory of Biological Chemistry, Department of Medicine, University of Ioannina, Greece
| | | | - Amalia Papadaki
- Intracellular Parasitism Group, Microbiology Department, Hellenic Pasteur Institute, Vas. Sofias 127, Athens 11521, Greece
| | - Olympia Tziouvara
- Intracellular Parasitism Group, Microbiology Department, Hellenic Pasteur Institute, Vas. Sofias 127, Athens 11521, Greece
| | - Evaggelia Xingi
- Light Microscopy Unit, Hellenic Pasteur Institute, Vas. Sofias 127, Athens 11521, Greece
| | - Stathis Frillingos
- Laboratory of Biological Chemistry, Department of Medicine, University of Ioannina, Greece.
| | - Haralabia Boleti
- Intracellular Parasitism Group, Microbiology Department, Hellenic Pasteur Institute, Vas. Sofias 127, Athens 11521, Greece; Light Microscopy Unit, Hellenic Pasteur Institute, Vas. Sofias 127, Athens 11521, Greece.
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10
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Arora K, Rai AK. Dependence of Leishmania parasite on host derived ATP: an overview of extracellular nucleotide metabolism in parasite. J Parasit Dis 2019; 43:1-13. [PMID: 30956439 PMCID: PMC6423245 DOI: 10.1007/s12639-018-1061-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2018] [Accepted: 11/24/2018] [Indexed: 12/29/2022] Open
Affiliation(s)
- Kashika Arora
- Department of Biotechnology, Motilal Nehru National Institute of Technology (MNNIT) Allahabad, Allahabad, 211004 U.P. India
- Present Address: Biomedical Research Center, Ghent University Global Campus, Incheon, 21985 South Korea
| | - Ambak Kumar Rai
- Department of Biotechnology, Motilal Nehru National Institute of Technology (MNNIT) Allahabad, Allahabad, 211004 U.P. India
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Nishtala SN, Arora A, Reyes J, Akabas MH. Accessibility of substituted cysteines in TM2 and TM10 transmembrane segments in the Plasmodium falciparum equilibrative nucleoside transporter PfENT1. J Biol Chem 2019; 294:1924-1935. [PMID: 30541922 DOI: 10.1074/jbc.ra118.006547] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Revised: 11/30/2018] [Indexed: 11/06/2022] Open
Abstract
Infection with Plasmodium species parasites causes malaria. Plasmodium parasites are purine auxotrophic. They import purines via an equilibrative nucleoside transporter (ENT). In P. falciparum, the most virulent species, the equilibrative nucleoside transporter 1 (PfENT1) represents the primary purine uptake pathway. This transporter is a potential target for the development of antimalarial drugs. In the absence of a high-resolution structure for either PfENT1 or a homologous ENT, we used the substituted cysteine accessibility method (SCAM) to investigate the membrane-spanning domain structure of PfENT1 to identify potential inhibitor-binding sites. We previously used SCAM to identify water-accessible residues that line the permeation pathway in transmembrane segment 11 (TM11). TM2 and TM10 lie adjacent to TM11 in an ab initio model of a homologous Leishmania donovani nucleoside transporter. To identify TM2 and TM10 residues in PfENT1 that are at least transiently on the water-accessible transporter surface, we assayed the reactivity of single cysteine-substitution mutants with three methanethiosulfonate (MTS) derivatives. Cysteines substituted for 12 of 14 TM2 segment residues reacted with MTS-ethyl-ammonium-biotin (MTSEA-biotin). At eight positions, MTSEA-biotin inhibited transport, and at four positions substrate transport was potentiated. On an α helical wheel projection of TM2, the four positions where potentiation occurred were located in a cluster on one side of the helix. In contrast, although MTSEA-biotin inhibited 9 of 10 TM10 cysteine-substituted mutants, the reactive residues did not form a pattern consistent with either an α helix or β sheet. These results may help identify the binding site(s) of PfENT1 inhibitors.
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Affiliation(s)
| | - Avish Arora
- From the Departments of Physiology and Biophysics
| | - Jorge Reyes
- From the Departments of Physiology and Biophysics
| | - Myles H Akabas
- From the Departments of Physiology and Biophysics, .,Neuroscience, and.,Medicine, Albert Einstein College of Medicine, Bronx, New York 10461
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12
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TOHIDI F, KAZEMI B, BANDEHPOUR M, SHARIFI I, RABIEI MR, SAEDI DEZAKI E, BABAEI Z. Transient Down-Regulation of Nucleoside Transporter 3 Gene Expression as a Drug Target in Leishmania major Using Antisense RNA Technology. IRANIAN JOURNAL OF PARASITOLOGY 2019; 14:111-119. [PMID: 31123475 PMCID: PMC6511602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Abstract
BACKGROUND This study was aimed to silencing the Nucleoside transporter 3 (NT3) permease nucleobases involved in the salvage pathway of Leishmania in order to disrupt purine nucleotide uptake in the parasite and consequently, destruction of the parasite. METHODS Overall, 502 bp fragment of the NT3 gene sequence was designed to produce an antisense transcript upon entry of the vector into the parasite. The NT3 construct was transfected into L. major promastigotes and NT3 gene expression was studied in vivo and in vitro conditions. RESULTS Relative expression NT3 gene in transgenic Leishmania was decreased in tenth day. The percentages and the number of amastigotes infected macrophages with transgenic L. major were less than infected macrophages with wild-type strain. Our results in two groups of BALB/c female mice (wild-type strain and mutant, n=4 each group) were showed that size and number of ulcers in BALB/c mice infected with transgenic Leishmania promastigotes were less than the BALB/c mice infected with wild-type parasites. CONCLUSION The results indicate the use of antisense RNA reduces of NT3 gene expression in L. major. More studies are required to obtain a new approach for treating Leishmania infection.
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Affiliation(s)
- Farideh TOHIDI
- Department of Medical Parasitology and Mycology, School of Medicine, Kerman University of Medical Sciences, Kerman, Iran, Infectious Diseases Research Center, Golestan University of Medical Sciences, Gorgan, Iran
| | - Bahram KAZEMI
- Cellular and Molecular Biology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran, Department of Biotechnology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran,Correspondence
| | - Mojgan BANDEHPOUR
- Cellular and Molecular Biology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran, Department of Biotechnology, School of Advanced Technologies in Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Iraj SHARIFI
- Department of Medical Parasitology and Mycology, School of Medicine, Kerman University of Medical Sciences, Kerman, Iran, Leishmaniasis Research Center, Kerman University of Medical Sciences, Kerman, Iran
| | - Mohammad Reza RABIEI
- Department of Statistics, School of Mathematical Sciences, Shahrood University of Technology, Shahrood, Iran
| | - Ebrahim SAEDI DEZAKI
- Department of Medical Parasitology and Mycology, School of Medicine, Shahrekord University of Medical Sciences, Shahrekord, Iran
| | - Zahra BABAEI
- Department of Medical Parasitology and Mycology, School of Medicine, Kerman University of Medical Sciences, Kerman, Iran, Leishmaniasis Research Center, Kerman University of Medical Sciences, Kerman, Iran,Correspondence
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13
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Lauri N, Bazzi Z, Alvarez CL, Leal Denis MF, Schachter J, Herlax V, Ostuni MA, Schwarzbaum PJ. ATPe Dynamics in Protozoan Parasites. Adapt or Perish. Genes (Basel) 2018; 10:E16. [PMID: 30591699 PMCID: PMC6356682 DOI: 10.3390/genes10010016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Revised: 12/18/2018] [Accepted: 12/19/2018] [Indexed: 01/25/2023] Open
Abstract
In most animals, transient increases of extracellular ATP (ATPe) are used for physiological signaling or as a danger signal in pathological conditions. ATPe dynamics are controlled by ATP release from viable cells and cell lysis, ATPe degradation and interconversion by ecto-nucleotidases, and interaction of ATPe and byproducts with cell surface purinergic receptors and purine salvage mechanisms. Infection by protozoan parasites may alter at least one of the mechanisms controlling ATPe concentration. Protozoan parasites display their own set of proteins directly altering ATPe dynamics, or control the activity of host proteins. Parasite dependent activation of ATPe conduits of the host may promote infection and systemic responses that are beneficial or detrimental to the parasite. For instance, activation of organic solute permeability at the host membrane can support the elevated metabolism of the parasite. On the other hand ecto-nucleotidases of protozoan parasites, by promoting ATPe degradation and purine/pyrimidine salvage, may be involved in parasite growth, infectivity, and virulence. In this review, we will describe the complex dynamics of ATPe regulation in the context of protozoan parasite⁻host interactions. Particular focus will be given to features of parasite membrane proteins strongly controlling ATPe dynamics. This includes evolutionary, genetic and cellular mechanisms, as well as structural-functional relationships.
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Affiliation(s)
- Natalia Lauri
- Institute of Biological Chemistry and Physicochemistry (IQUIFIB) "Prof. Alejandro C. Paladini", Faculty of Pharmacy and Biochemistry, University of Buenos Aires, National Scientific and Technical Research Council (CONICET), Junín 956 Buenos Aires, Argentina.
- Faculty of Pharmacy and Biochemistry, Department of Biological Chemistry, Chair of Biological Chemistry, University of Buenos Aires, Junín 956 Buenos Aires, Argentina.
| | - Zaher Bazzi
- Institute of Biological Chemistry and Physicochemistry (IQUIFIB) "Prof. Alejandro C. Paladini", Faculty of Pharmacy and Biochemistry, University of Buenos Aires, National Scientific and Technical Research Council (CONICET), Junín 956 Buenos Aires, Argentina.
| | - Cora L Alvarez
- Institute of Biological Chemistry and Physicochemistry (IQUIFIB) "Prof. Alejandro C. Paladini", Faculty of Pharmacy and Biochemistry, University of Buenos Aires, National Scientific and Technical Research Council (CONICET), Junín 956 Buenos Aires, Argentina.
- Faculty of Exact and Natural Sciences, Department of Biodiversity and Experimental Biology, University of Buenos Aires, Intendente Güiraldes, Buenos Aires 2160, Argentina.
| | - María F Leal Denis
- Institute of Biological Chemistry and Physicochemistry (IQUIFIB) "Prof. Alejandro C. Paladini", Faculty of Pharmacy and Biochemistry, University of Buenos Aires, National Scientific and Technical Research Council (CONICET), Junín 956 Buenos Aires, Argentina.
- Chair of Analytical Chemistry and Physicochemistry, Faculty of Pharmacy and Biochemistry, Department of Analytical Chemistry, University of Buenos Aires, Junín 956 Buenos Aires, Argentina.
| | - Julieta Schachter
- Institute of Biological Chemistry and Physicochemistry (IQUIFIB) "Prof. Alejandro C. Paladini", Faculty of Pharmacy and Biochemistry, University of Buenos Aires, National Scientific and Technical Research Council (CONICET), Junín 956 Buenos Aires, Argentina.
| | - Vanesa Herlax
- Biochemistry Research Institute of La Plata (INIBIOLP) "Prof. Dr. Rodolfo R. Brenner", Faculty of Medical Sciences, National University of La Plata, National Scientific and Technical Research Council, Av. 60 y Av. 120 La Plata, Argentina.
- National University of La Plata, Faculty of Medical Sciences, Av. 60 y Av. 120 La Plata, Argentina.
| | - Mariano A Ostuni
- UMR-S1134, Integrated Biology of Red Blood Cells, INSERM, Paris Diderot University, Sorbonne Paris Cité, University of La Réunion, University of Antilles, F-75015 Paris, France.
- National Institute of Blood Transfusion (INTS), Laboratory of Excellence GR-Ex, F-75015 Paris, France.
| | - Pablo J Schwarzbaum
- Institute of Biological Chemistry and Physicochemistry (IQUIFIB) "Prof. Alejandro C. Paladini", Faculty of Pharmacy and Biochemistry, University of Buenos Aires, National Scientific and Technical Research Council (CONICET), Junín 956 Buenos Aires, Argentina.
- Faculty of Pharmacy and Biochemistry, Department of Biological Chemistry, Chair of Biological Chemistry, University of Buenos Aires, Junín 956 Buenos Aires, Argentina.
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14
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Muxel SM, Aoki JI, Fernandes JCR, Laranjeira-Silva MF, Zampieri RA, Acuña SM, Müller KE, Vanderlinde RH, Floeter-Winter LM. Arginine and Polyamines Fate in Leishmania Infection. Front Microbiol 2018; 8:2682. [PMID: 29379478 PMCID: PMC5775291 DOI: 10.3389/fmicb.2017.02682] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Accepted: 12/22/2017] [Indexed: 01/22/2023] Open
Abstract
Leishmania is a protozoan parasite that alternates its life cycle between the sand fly and the mammalian host macrophages, involving several environmental changes. The parasite responds to these changes by promoting a rapid metabolic adaptation through cellular signaling modifications that lead to transcriptional and post-transcriptional gene expression regulation and morphological modifications. Molecular approaches such as gene expression regulation, next-generation sequencing (NGS), microRNA (miRNA) expression profiling, in cell Western blot analyses and enzymatic activity profiling, have been used to characterize the infection of murine BALB/c and C57BL/6 macrophages, as well as the human monocytic cell-lineage THP-1, with Leishmania amazonensis wild type (La-WT) or arginase knockout (La-arg-). These models are being used to elucidate physiological roles of arginine and polyamines pathways and the importance of arginase for the establishment of the infection. In this review, we will describe the main aspects of Leishmania-host interaction, focusing on the arginine and polyamines pathways and pointing to possible targets to be used for prognosis and/or in the control of the infection. The parasite enzymes, arginase and nitric oxide synthase-like, have essential roles in the parasite survival and in the maintenance of infection. On the other hand, in mammalian macrophages, defense mechanisms are activated inducing alterations in the mRNA, miRNA and enzymatic profiles that lead to the control of infection. Furthermore, the genetic background of both parasite and host are also important to define the fate of infection.
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Affiliation(s)
- Sandra M Muxel
- Department of Physiology, Institute of Biosciences, University of São Paulo, São Paulo, Brazil
| | - Juliana I Aoki
- Department of Physiology, Institute of Biosciences, University of São Paulo, São Paulo, Brazil
| | - Juliane C R Fernandes
- Department of Physiology, Institute of Biosciences, University of São Paulo, São Paulo, Brazil
| | | | - Ricardo A Zampieri
- Department of Physiology, Institute of Biosciences, University of São Paulo, São Paulo, Brazil
| | - Stephanie M Acuña
- Department of Physiology, Institute of Biosciences, University of São Paulo, São Paulo, Brazil
| | - Karl E Müller
- Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Rubia H Vanderlinde
- Department of Physiology, Institute of Biosciences, University of São Paulo, São Paulo, Brazil
| | - Lucile M Floeter-Winter
- Department of Physiology, Institute of Biosciences, University of São Paulo, São Paulo, Brazil
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15
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Gazanion E, Vergnes B. Protozoan Parasite Auxotrophies and Metabolic Dependencies. EXPERIENTIA SUPPLEMENTUM (2012) 2018; 109:351-375. [PMID: 30535605 DOI: 10.1007/978-3-319-74932-7_9] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Diseases caused by protozoan parasites have a major impact on world health. These early branching eukaryotes cause significant morbidity and mortality in humans and livestock. During evolution, protozoan parasites have evolved toward complex life cycles in multiple host organisms with different nutritional resources. The conservation of functional metabolic pathways required for these successive environments is therefore a prerequisite for parasitic lifestyle. Nevertheless, parasitism drives genome evolution toward gene loss and metabolic dependencies (including strict auxotrophy), especially for obligatory intracellular parasites. In this chapter, we will compare and contrast how protozoan parasites have perfected this metabolic adaptation by focusing on specific auxotrophic pathways and scavenging strategies used by clinically relevant apicomplexan and trypanosomatid parasites to access host's nutritional resources. We will further see how these metabolic dependencies have in turn been exploited for therapeutic purposes against these human pathogens.
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Affiliation(s)
- Elodie Gazanion
- MIVEGEC, IRD, CNRS, University of Montpellier, Montpellier, France
| | - Baptiste Vergnes
- MIVEGEC, IRD, CNRS, University of Montpellier, Montpellier, France.
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16
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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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17
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Schmidt RS, Macêdo JP, Steinmann ME, Salgado AG, Bütikofer P, Sigel E, Rentsch D, Mäser P. Transporters of Trypanosoma brucei-phylogeny, physiology, pharmacology. FEBS J 2017; 285:1012-1023. [PMID: 29063677 DOI: 10.1111/febs.14302] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 09/18/2017] [Accepted: 10/18/2017] [Indexed: 12/12/2022]
Abstract
Trypanosoma brucei comprise the causative agents of sleeping sickness, T. b. gambiense and T. b. rhodesiense, as well as the livestock-pathogenic T. b. brucei. The parasites are transmitted by the tsetse fly and occur exclusively in sub-Saharan Africa. T. brucei are not only lethal pathogens but have also become model organisms for molecular parasitology. We focus here on membrane transport proteins of T. brucei, their contribution to homeostasis and metabolism in the context of a parasitic lifestyle, and their pharmacological role as potential drug targets or routes of drug entry. Transporters and channels in the plasma membrane are attractive drug targets as they are accessible from the outside. Alternatively, they can be exploited to selectively deliver harmful substances into the trypanosome's interior. Both approaches require the targeted transporter to be essential: in the first case to kill the trypanosome, in the second case to prevent drug resistance due to loss of the transporter. By combining functional and phylogenetic analyses, we were mining the T. brucei predicted proteome for transporters of pharmacological significance. Here, we review recent progress in the identification of transporters of lipid precursors, amino acid permeases and ion channels in T. brucei.
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Affiliation(s)
- Remo S Schmidt
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Switzerland
| | - Juan P Macêdo
- Institute of Plant Sciences, University of Bern, Switzerland
| | - Michael E Steinmann
- Institute of Biochemistry and Molecular Medicine, University of Bern, Switzerland
| | | | - Peter Bütikofer
- Institute of Biochemistry and Molecular Medicine, University of Bern, Switzerland
| | - Erwin Sigel
- Institute of Biochemistry and Molecular Medicine, University of Bern, Switzerland
| | - Doris Rentsch
- Institute of Plant Sciences, University of Bern, Switzerland
| | - Pascal Mäser
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Switzerland
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18
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Boswell-Casteel RC, Johnson JM, Roe-Žurž Z, Duggan KD, Schmitz H, Hays FA. Expression and purification of human and Saccharomyces cerevisiae equilibrative nucleoside transporters. Protein Expr Purif 2017; 142:68-74. [PMID: 28918196 DOI: 10.1016/j.pep.2017.09.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Revised: 09/05/2017] [Accepted: 09/05/2017] [Indexed: 01/09/2023]
Abstract
Nucleosides play an essential role in the physiology of eukaryotes by acting as metabolic precursors in de novo nucleic acid synthesis and energy metabolism. Nucleosides also act as ligands for purinergic receptors. Equilibrative nucleoside transporters (ENTs) are polytopic integral membrane proteins that aid in regulating plasmalemmal flux of purine and pyrimidine nucleosides and nucleobases. ENTs exhibit broad substrate selectivity across different isoforms and utilize diverse mechanisms to drive substrate flux across membranes. However, the molecular mechanisms and chemical determinants of ENT-mediated substrate recognition, binding, inhibition, and transport are poorly understood. To determine how ENT-mediated transport occurs at the molecular level, greater chemical insight and assays employing purified protein are essential. This article focuses on the expression and purification of human ENT1, human ENT2, and Saccharomyces cerevisiae ScENT1 using novel expression and purification strategies to isolate recombinant ENTs. ScENT1, hENT1, and hENT2 were expressed in W303 Saccharomyces cerevisiae cells and detergent solubilized from the membrane. After detergent extraction, these ENTs were further purified using immobilized metal affinity chromatography and size exclusion chromatography. This effort resulted in obtaining quantities of purified protein sufficient for future biophysical analysis.
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Affiliation(s)
- Rebba C Boswell-Casteel
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Jennifer M Johnson
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Zygy Roe-Žurž
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, CA 94143, USA
| | - Kelli D Duggan
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Hannah Schmitz
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Franklin A Hays
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; Stephenson Oklahoma Cancer Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; Harold Hamm Diabetes Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA.
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19
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Romero AH, Medina R, Alcala A, García-Marchan Y, Núñez-Duran J, Leañez J, Mijoba A, Ciangherotti C, Serrano-Martín X, López SE. Design, synthesis, structure-activity relationship and mechanism of action studies of a series of 4-chloro-1-phthalazinyl hydrazones as a potent agent against Leishmania braziliensis. Eur J Med Chem 2017; 127:606-620. [DOI: 10.1016/j.ejmech.2017.01.022] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Revised: 01/12/2017] [Accepted: 01/13/2017] [Indexed: 11/29/2022]
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20
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Moreira DS, Murta SMF. Involvement of nucleoside diphosphate kinase b and elongation factor 2 in Leishmania braziliensis antimony resistance phenotype. Parasit Vectors 2016; 9:641. [PMID: 27964761 PMCID: PMC5155413 DOI: 10.1186/s13071-016-1930-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Accepted: 12/05/2016] [Indexed: 02/07/2023] Open
Abstract
Background Nucleoside diphosphate kinase b (NDKb) is responsible for nucleoside triphosphates synthesis and it has key role in the purine metabolism in trypanosomatid protozoans. Elongation factor 2 (EF2) is an important factor for protein synthesis. Recently, our phosphoproteomic analysis demonstrated that NDKb and EF2 proteins were phosphorylated and dephosphorylated in antimony (SbIII)-resistant L. braziliensis line compared to its SbIII-susceptible pair, respectively. Methods In this study, the overexpression of NDKb and EF2 genes in L. braziliensis and L. infantum was performed to investigate the contribution of these proteins in the SbIII-resistance phenotype. Furthermore, we examined the role of lamivudine on SbIII susceptibility in clones that overexpress the NDKb gene, and the effect of EF2 kinase (EF2K) inhibitor on the growth of EF2-overexpressing parasites. Results Western blot analysis demonstrated that NDKb and EF2 proteins are more and less expressed, respectively, in SbIII-resistant line of L. braziliensis than its wild-type (WTS) counterpart, corroborating our previous phosphoproteomic data. NDKb or EF2-overexpressing L. braziliensis lines were 1.6 to 2.1-fold more resistant to SbIII than the untransfected WTS line. In contrast, no difference in SbIII susceptibility was observed in L. infantum parasites overexpressing NDKb or EF2. Susceptibility assays showed that NDKb-overexpressing L. braziliensis lines presented elevated resistance to lamivudine, an antiviral agent, but it did not alter the leishmanicidal activity in association with SbIII. EF2-overexpressing L. braziliensis clone was slightly more resistant to EF2K inhibitor than the WTS line. Surprisingly, this inhibitor increased the antileishmanial effect of SbIII, suggesting that this association might be a valuable strategy for leishmaniasis chemotherapy. Conclusion Our findings represent the first study of NDKb and EF2 genes overexpression that demonstrates an increase of SbIII resistance in L. braziliensis which can contribute to develop new strategies for leishmaniasis treatment.
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Affiliation(s)
- Douglas S Moreira
- Centro de Pesquisas René Rachou CPqRR, Fundação Oswaldo Cruz - FIOCRUZ, Avenida Augusto de Lima 1715, Belo Horizonte, MG, Brazil
| | - Silvane M F Murta
- Centro de Pesquisas René Rachou CPqRR, Fundação Oswaldo Cruz - FIOCRUZ, Avenida Augusto de Lima 1715, Belo Horizonte, MG, Brazil.
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21
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Boswell-Casteel RC, Hays FA. Equilibrative nucleoside transporters-A review. NUCLEOSIDES NUCLEOTIDES & NUCLEIC ACIDS 2016; 36:7-30. [PMID: 27759477 DOI: 10.1080/15257770.2016.1210805] [Citation(s) in RCA: 125] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Equilibrative nucleoside transporters (ENTs) are polytopic integral membrane proteins that mediate the transport of nucleosides, nucleobases, and therapeutic analogs. The best-characterized ENTs are the human transporters hENT1 and hENT2. However, non-mammalian eukaryotic ENTs have also been studied (e.g., yeast, parasitic protozoa). ENTs are major pharmaceutical targets responsible for modulating the efficacy of more than 30 approved drugs. However, the molecular mechanisms and chemical determinants of ENT-mediated substrate recognition, binding, inhibition, and transport are poorly understood. This review highlights findings on the characterization of ENTs by surveying studies on genetics, permeant and inhibitor interactions, mutagenesis, and structural models of ENT function.
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Affiliation(s)
- Rebba C Boswell-Casteel
- a Department of Biochemistry and Molecular Biology , University of Oklahoma Health Sciences Center , Oklahoma City , OK , USA
| | - Franklin A Hays
- a Department of Biochemistry and Molecular Biology , University of Oklahoma Health Sciences Center , Oklahoma City , OK , USA.,b Stephenson Cancer Center , University of Oklahoma Health Sciences Center , Oklahoma City , OK , USA.,c Harold Hamm Diabetes Center , University of Oklahoma Health Sciences Center , Oklahoma City , OK , USA
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22
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Figueiredo ABD, Souza-Testasicca MC, Afonso LCC. Purinergic signaling and infection by Leishmania: A new approach to evasion of the immune response. Biomed J 2016; 39:244-250. [PMID: 27793266 PMCID: PMC6139394 DOI: 10.1016/j.bj.2016.08.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Revised: 05/18/2016] [Accepted: 08/02/2016] [Indexed: 12/20/2022] Open
Abstract
Infection by protozoan parasites is part of the most common Tropical Neglected Diseases. In the case of leishmaniasis, several millions of people are at risk of contracting the disease. In spite of innumerous studies that elucidated the immune response capable of killing the parasite, the understanding of the evasion mechanisms utilized by the parasite to survive within the very cell responsible for its destruction is still incomplete. In this review, we offer a new approach to the control of the immune response against the parasite. The ability of the parasite to modulate the levels of extracellular ATP and adenosine either by directly acting on the levels of these molecules or by inducing the expression of CD39 and CD73 on the infected cell may influence the magnitude of the immune response against the parasite contributing to its growth and survival.
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Affiliation(s)
- Amanda Braga de Figueiredo
- Immunoparasitology Laboratory, Department of Biological Sciences, ICEB/NUPEB, Federal University of Ouro Preto, Brazil
| | | | - Luis Carlos Crocco Afonso
- Immunoparasitology Laboratory, Department of Biological Sciences, ICEB/NUPEB, Federal University of Ouro Preto, Brazil.
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23
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Aoki JI, Coelho AC, Muxel SM, Zampieri RA, Sanchez EMR, Nerland AH, Floeter-Winter LM, Cotrim PC. Characterization of a Novel Endoplasmic Reticulum Protein Involved in Tubercidin Resistance in Leishmania major. PLoS Negl Trop Dis 2016; 10:e0004972. [PMID: 27606425 PMCID: PMC5015992 DOI: 10.1371/journal.pntd.0004972] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Accepted: 08/11/2016] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Tubercidin (TUB) is a toxic adenosine analog with potential antiparasitic activity against Leishmania, with mechanism of action and resistance that are not completely understood. For understanding the mechanisms of action and identifying the potential metabolic pathways affected by this drug, we employed in this study an overexpression/selection approach using TUB for the identification of potential targets, as well as, drug resistance genes in L. major. Although, TUB is toxic to the mammalian host, these findings can provide evidences for a rational drug design based on purine pathway against leishmaniasis. METHODOLOGY/PRINCIPAL FINDINGS After transfection of a cosmid genomic library into L. major Friedlin (LmjF) parasites and application of the overexpression/selection method, we identified two cosmids (cosTUB1 and cosTU2) containing two different loci capable of conferring significant levels of TUB resistance. In the cosTUB1 contained a gene encoding NUPM1-like protein, which has been previously described as associated with TUB resistance in L. amazonensis. In the cosTUB2 we identified and characterized a gene encoding a 63 kDa protein that we denoted as tubercidin-resistance protein (TRP). Functional analysis revealed that the transfectants were less susceptible to TUB than LmjF parasites or those transfected with the control vector. In addition, the trp mRNA and protein levels in cosTUB2 transfectants were higher than LmjF. TRP immunolocalization revealed that it was co-localized to the endoplasmic reticulum (ER), a cellular compartment with many functions. In silico predictions indicated that TRP contains only a hypothetical transmembrane domain. Thus, it is likely that TRP is a lumen protein involved in multidrug efflux transport that may be involved in the purine metabolic pathway. CONCLUSIONS/SIGNIFICANCE This study demonstrated for the first time that TRP is associated with TUB resistance in Leishmania. The next challenge is to determine how TRP mediates TUB resistance and whether purine metabolism is affected by this protein in the parasite. Finally, these findings may be helpful for the development of alternative anti-leishmanial drugs that target purine pathway.
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Affiliation(s)
- Juliana Ide Aoki
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
| | - Adriano Cappellazzo Coelho
- Departamento de Parasitologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
- Departamento de Biologia Animal, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, Brazil
| | - Sandra Marcia Muxel
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
| | - Ricardo Andrade Zampieri
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
| | | | | | | | - Paulo Cesar Cotrim
- Instituto de Medicina Tropical, Departamento de Moléstias Infecciosas e Parasitárias, Faculdade de Medicina, Universidade de São Paulo, São Paulo, Brazil
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Kariithi HM, Boeren S, Murungi EK, Vlak JM, Abd-Alla AMM. A proteomics approach reveals molecular manipulators of distinct cellular processes in the salivary glands of Glossina m. morsitans in response to Trypanosoma b. brucei infections. Parasit Vectors 2016; 9:424. [PMID: 27485005 PMCID: PMC4969678 DOI: 10.1186/s13071-016-1714-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Accepted: 07/20/2016] [Indexed: 12/28/2022] Open
Abstract
Background Glossina m. morsitans is the primary vector of the Trypanosoma brucei group, one of the causative agents of African trypanosomoses. The parasites undergo metacyclogenesis, i.e. transformation into the mammalian-infective metacyclic trypomastigote (MT) parasites, in the salivary glands (SGs) of the tsetse vector. Since the MT-parasites are largely uncultivable in vitro, information on the molecular processes that facilitate metacyclogenesis is scanty. Methods To bridge this knowledge gap, we employed tandem mass spectrometry to investigate protein expression modulations in parasitized (T. b. brucei-infected) and unparasitized SGs of G. m. morsitans. We annotated the identified proteins into gene ontologies and mapped the up- and downregulated proteins within protein-protein interaction (PPI) networks. Results We identified 361 host proteins, of which 76.6 % (n = 276) and 22.3 % (n = 81) were up- and downregulated, respectively, in parasitized SGs compared to unparasitized SGs. Whilst 32 proteins were significantly upregulated (> 10-fold), only salivary secreted adenosine was significantly downregulated. Amongst the significantly upregulated proteins, there were proteins associated with blood feeding, immunity, cellular proliferation, homeostasis, cytoskeletal traffic and regulation of protein turnover. The significantly upregulated proteins formed major hubs in the PPI network including key regulators of the Ras/MAPK and Ca2+/cAMP signaling pathways, ubiquitin-proteasome system and mitochondrial respiratory chain. Moreover, we identified 158 trypanosome-specific proteins, notable of which were proteins in the families of the GPI-anchored surface glycoproteins, kinetoplastid calpains, peroxiredoxins, retrotransposon host spot multigene and molecular chaperones. Whilst immune-related trypanosome proteins were over-represented, membrane transporters and proteins involved in translation repression (e.g. ribosomal proteins) were under-represented, potentially reminiscent of the growth-arrested MT-parasites. Conclusions Our data implicate the significantly upregulated proteins as manipulators of diverse cellular processes in response to T. b. brucei infection, potentially to prepare the MT-parasites for invasion and evasion of the mammalian host immune defences. We discuss potential strategies to exploit our findings in enhancement of trypanosome refractoriness or reduce the vector competence of the tsetse vector. Electronic supplementary material The online version of this article (doi:10.1186/s13071-016-1714-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Henry M Kariithi
- Biotechnology Research Institute, Kenya Agricultural and Livestock Research Organization, P.O Box 57811, 00200, Kaptagat Rd, Loresho, Nairobi, Kenya. .,Insect Pest Control Laboratories, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, International Atomic Energy Agency, Wagrammer Straße 5, Vienna, Austria.
| | - Sjef Boeren
- Laboratory of Biochemistry, Wageningen University, Dreijenlaan 3, 6703, HA, Wageningen, The Netherlands
| | - Edwin K Murungi
- Department of Biochemistry and Molecular Biology, Egerton University, P.O. Box 536, 20115, Njoro, Kenya
| | - Just M Vlak
- Laboratory of Virology, Wageningen University, Droevendaalsesteeg 1, 6708, PB, Wageningen, The Netherlands
| | - Adly M M Abd-Alla
- Insect Pest Control Laboratories, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, International Atomic Energy Agency, Wagrammer Straße 5, Vienna, Austria.
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Martin JL, Yates PA, Boitz JM, Koop DR, Fulwiler AL, Cassera MB, Ullman B, Carter NS. A role for adenine nucleotides in the sensing mechanism to purine starvation in Leishmania donovani. Mol Microbiol 2016; 101:299-313. [PMID: 27062185 DOI: 10.1111/mmi.13390] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/30/2016] [Indexed: 01/25/2023]
Abstract
Purine salvage by Leishmania is an obligatory nutritional process that impacts both cell viability and growth. Previously, we have demonstrated that the removal of purines in culture provokes significant metabolic changes that enable Leishmania to survive prolonged periods of purine starvation. In order to understand how Leishmania sense and respond to changes in their purine environment, we have exploited several purine pathway mutants, some in which adenine and guanine nucleotide metabolism is uncoupled. While wild type parasites grow in any one of a variety of naturally occurring purines, the proliferation of these purine pathway mutants requires specific types or combinations of exogenous purines. By culturing purine pathway mutants in high levels of extracellular purines that are either permissive or non-permissive for growth and monitoring for previously defined markers of the adaptive response to purine starvation, we determined that adaptation arises from a surveillance of intracellular purine nucleotide pools rather than from a direct sensing of the extracellular purine content of the environment. Specifically, our data suggest that perturbation of intracellular adenine-containing nucleotide pools provides a crucial signal for inducing the metabolic changes necessary for the long-term survival of Leishmania in a purine-scarce environment.
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Affiliation(s)
- Jessica L Martin
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, OR, 97239-3098, USA
| | - Phillip A Yates
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, OR, 97239-3098, USA
| | - Jan M Boitz
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, OR, 97239-3098, USA
| | - Dennis R Koop
- Physiology and Pharmacology, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, OR, 97239-3098, USA
| | - Audrey L Fulwiler
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, OR, 97239-3098, USA
| | - Maria Belen Cassera
- Department of Biochemistry and Virginia Tech Center for Drug Discovery, M/C 0308, Virginia, Tech, Blacksburg, VA, 24061, USA
| | - Buddy Ullman
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, OR, 97239-3098, USA
| | - Nicola S Carter
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, OR, 97239-3098, USA
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Targeting the Plasmodium vivax equilibrative nucleoside transporter 1 (PvENT1) for antimalarial drug development. INTERNATIONAL JOURNAL FOR PARASITOLOGY-DRUGS AND DRUG RESISTANCE 2015; 6:1-11. [PMID: 26862473 PMCID: PMC4706624 DOI: 10.1016/j.ijpddr.2015.11.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Revised: 11/18/2015] [Accepted: 11/25/2015] [Indexed: 11/26/2022]
Abstract
Infection with Plasmodium falciparum and vivax cause most cases of malaria. Emerging resistance to current antimalarial medications makes new drug development imperative. Ideally a new antimalarial drug should treat both falciparum and vivax malaria. Because malaria parasites are purine auxotrophic, they rely on purines imported from the host erythrocyte via Equilibrative Nucleoside Transporters (ENTs). Thus, the purine import transporters represent a potential target for antimalarial drug development. For falciparum parasites the primary purine transporter is the P. falciparum Equilibrative Nucleoside Transporter Type 1 (PfENT1). Recently we identified potent PfENT1 inhibitors with nanomolar IC50 values using a robust, yeast-based high throughput screening assay. In the current work we characterized the Plasmodium vivax ENT1 (PvENT1) homologue and its sensitivity to the PfENT1 inhibitors. We expressed a yeast codon-optimized PvENT1 gene in Saccharomyces cerevisiae. PvENT1-expressing yeast imported both purines ([3H]adenosine) and pyrimidines ([3H]uridine), whereas wild type (fui1Δ) yeast did not. Based on radiolabel substrate uptake inhibition experiments, inosine had the lowest IC50 (3.8 μM), compared to guanosine (14.9 μM) and adenosine (142 μM). For pyrimidines, thymidine had an IC50 of 183 μM (vs. cytidine and uridine; mM range). IC50 values were higher for nucleobases compared to the corresponding nucleosides; hypoxanthine had a 25-fold higher IC50 than inosine. The archetypal human ENT1 inhibitor 4-nitrobenzylthioinosine (NBMPR) had no effect on PvENT1, whereas dipyridamole inhibited PvENT1, albeit with a 40 μM IC50, a 1000-fold less sensitive than human ENT1 (hENT1). The PfENT1 inhibitors blocked transport activity of PvENT1 and the five known naturally occurring non-synonymous single nucleotide polymorphisms (SNPs) with similar IC50 values. Thus, the PfENT1 inhibitors also target PvENT1. This implies that development of novel antimalarial drugs that target both falciparum and vivax ENT1 may be feasible. PvENT1 can be functionally expressed in Saccharomyces cerevisiae. PvENT1 transports purine and pyrimidine nucleosides and nucleobases but does not transport nucleotides. PvENT1 is inhibited by recently described PfENT1 inhibitors with similar potency. Identified PvENT1 non-synonymous SNPs do not change PfENT1 inhibitor potency. Plasmodium ENTs may be feasible target for development of novel antimalarial drugs.
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Key Words
- ACT, Artemisinin-based Combination Therapies
- CQ, chloroquine
- Drug development
- EC50, concentration causing 50% of maximal effect
- ENT, equilibrative nucleoside transporter
- EV, empty vector
- HTS, high throughput screen
- IC50, concentration causing 50% inhibition
- Malaria
- NBMPR, 4-nitrobenzylthioinosine
- Nucleoside/nucleobase transport
- Parasite
- PfENT1, P. falciparum ENT type 1
- Plasmodium vivax
- Purines
- PvENT1, P. vivax ENT type 1
- SDM, synthetic defined media
- SNP, single nucleotide polymorphism
- Single-nucleotide polymorphism (SNP)
- Transporter
- WHO, World Health Organization
- WT, wild type
- hENT1, human ENT type 1
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Li Q, Leija C, Rijo-Ferreira F, Chen J, Cestari I, Stuart K, Tu BP, Phillips MA. GMP synthase is essential for viability and infectivity of Trypanosoma brucei despite a redundant purine salvage pathway. Mol Microbiol 2015; 97:1006-20. [PMID: 26043892 DOI: 10.1111/mmi.13083] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/04/2015] [Indexed: 12/28/2022]
Abstract
The causative agent of human African trypanosomiasis, Trypanosoma brucei, lacks de novo purine biosynthesis and depends on purine salvage from the host. The purine salvage pathway is redundant and contains two routes to guanosine-5'-monophosphate (GMP) formation: conversion from xanthosine-5'-monophosphate (XMP) by GMP synthase (GMPS) or direct salvage of guanine by hypoxanthine-guanine phosphoribosyltransferase (HGPRT). We show recombinant T. brucei GMPS efficiently catalyzes GMP formation. Genetic knockout of GMPS in bloodstream parasites led to depletion of guanine nucleotide pools and was lethal. Growth of gmps null cells was only rescued by supraphysiological guanine concentrations (100 μM) or by expression of an extrachromosomal copy of GMPS. Hypoxanthine was a competitive inhibitor of guanine rescue, consistent with a common uptake/metabolic conversion mechanism. In mice, gmps null parasites were unable to establish an infection demonstrating that GMPS is essential for virulence and that plasma guanine is insufficient to support parasite purine requirements. These data validate GMPS as a potential therapeutic target for treatment of human African trypanosomiasis. The ability to strategically inhibit key metabolic enzymes in the purine pathway unexpectedly bypasses its functional redundancy by exploiting both the nature of pathway flux and the limited nutrient environment of the parasite's extracellular niche.
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Affiliation(s)
- Qiong Li
- Department of Pharmacology, University of Texas Southwestern Medical Center at Dallas, 6001 Forest Park Rd, Dallas, TX, 75390-9041, USA
| | - Christopher Leija
- Department of Pharmacology, University of Texas Southwestern Medical Center at Dallas, 6001 Forest Park Rd, Dallas, TX, 75390-9041, USA
| | - Filipa Rijo-Ferreira
- Department of Neuroscience, University of Texas Southwestern Medical Center at Dallas, 6001 Forest Park Rd, Dallas, TX, 75390-9041, USA.,Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal.,Graduate Program in Areas of Basic and Applied Biology, Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal
| | - Jun Chen
- Department of Biochemistry, University of Texas Southwestern Medical Center at Dallas, 6001 Forest Park Rd, Dallas, TX, 75390-9041, USA
| | - Igor Cestari
- Seattle Biomedical Research Institute, 307 Westlake Avenue North, Suite 500, Seattle, WA, 98109-5219, USA
| | - Kenneth Stuart
- Seattle Biomedical Research Institute, 307 Westlake Avenue North, Suite 500, Seattle, WA, 98109-5219, USA
| | - Benjamin P Tu
- Department of Biochemistry, University of Texas Southwestern Medical Center at Dallas, 6001 Forest Park Rd, Dallas, TX, 75390-9041, USA
| | - Margaret A Phillips
- Department of Pharmacology, University of Texas Southwestern Medical Center at Dallas, 6001 Forest Park Rd, Dallas, TX, 75390-9041, USA
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Thimm D, Schiedel AC, Peti-Peterdi J, Kishore BK, Müller CE. The nucleobase adenine as a signalling molecule in the kidney. Acta Physiol (Oxf) 2015; 213:808-18. [PMID: 25627062 DOI: 10.1111/apha.12452] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Revised: 12/07/2014] [Accepted: 01/05/2015] [Indexed: 11/30/2022]
Abstract
In 2002, the first receptor activated by the nucleobase adenine was discovered in rats. In the past years, two adenine receptors (AdeRs) in mice and one in Chinese hamsters, all of which belong to the family of G protein-coupled receptors (GPCRs), were cloned and pharmacologically characterized. Based on the nomenclature for other purinergic receptor families (P1 for adenosine receptors and P2 for nucleotide, e.g. ATP, receptors), AdeRs were designated P0 receptors. Pharmacological data indicate the existence of G protein-coupled AdeRs in pigs and humans as well; however, those have not been cloned so far. Current data suggest a role for adenine and AdeRs in renal proximal tubules. Furthermore, AdeRs are suggested to be functional counterplayers of vasopressin in the collecting duct system, thus exerting diuretic effects. We are only at the beginning of understanding the significance of this new class of purinergic receptors, which might become future drug targets.
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Affiliation(s)
- D. Thimm
- PharmaCenter Bonn; Pharmaceutical Institute, Pharmaceutical Chemistry I; University of Bonn; Bonn Germany
| | - A. C. Schiedel
- PharmaCenter Bonn; Pharmaceutical Institute, Pharmaceutical Chemistry I; University of Bonn; Bonn Germany
| | - J. Peti-Peterdi
- Department of Physiology and Biophysics; Zilkha Neurogenetic Institute; University of Southern California; Los Angeles CA USA
- Department of Medicine; Zilkha Neurogenetic Institute; University of Southern California; Los Angeles CA USA
| | - B. K. Kishore
- Nephrology Research; Department of Veterans Affairs Salt Lake City Health Care System; Salt Lake City UT USA
- Department of Internal Medicine; University of Utah Health Sciences Center; Salt Lake City UT USA
- Center on Aging; University of Utah Health Sciences Center; Salt Lake City UT USA
| | - C. E. Müller
- PharmaCenter Bonn; Pharmaceutical Institute, Pharmaceutical Chemistry I; University of Bonn; Bonn Germany
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Llanes A, Restrepo CM, Del Vecchio G, Anguizola FJ, Lleonart R. The genome of Leishmania panamensis: insights into genomics of the L. (Viannia) subgenus. Sci Rep 2015; 5:8550. [PMID: 25707621 PMCID: PMC4338418 DOI: 10.1038/srep08550] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Accepted: 01/26/2015] [Indexed: 12/21/2022] Open
Abstract
Kinetoplastid parasites of the Leishmania genus cause several forms of leishmaniasis. Leishmania species pathogenic to human are separated into two subgenera, Leishmania (Leishmania) and L. (Viannia). Species from the Viannia subgenus cause predominantly cutaneous leishmaniasis in Central and South America, occasionally leading to more severe clinical presentations. Although the genomes of several species of Leishmania have been sequenced to date, only one belongs to this rather different subgenus. Here we explore the unique features of the Viannia subgenus by sequencing and analyzing the genome of L. (Viannia) panamensis. Against a background of conservation in gene content and synteny, we found key differences at the genomic level that may explain the occurrence of molecular processes involving nucleic acid manipulation and differential modification of surface glycoconjugates. These differences may in part explain some phenotypic characteristics of the Viannia parasites, including their increased adaptive capacity and enhanced metastatic ability.
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Affiliation(s)
- Alejandro Llanes
- 1] Centro de Biología Celular y Molecular de Enfermedades, Instituto de Investigaciones Científicas y Servicios de Alta Tecnología (INDICASAT AIP), Ciudad del Saber, Panamá, Panamá [2] Facultad de Ciencias de la Salud Dr. William C. Gorgas, Universidad Latina de Panamá, Panamá, Panamá [3] Department of Biotechnology, Acharya Nagarjuna University, Guntur, India
| | - Carlos Mario Restrepo
- 1] Centro de Biología Celular y Molecular de Enfermedades, Instituto de Investigaciones Científicas y Servicios de Alta Tecnología (INDICASAT AIP), Ciudad del Saber, Panamá, Panamá [2] Department of Biotechnology, Acharya Nagarjuna University, Guntur, India
| | - Gina Del Vecchio
- Facultad de Ciencias de la Salud Dr. William C. Gorgas, Universidad Latina de Panamá, Panamá, Panamá
| | - Franklin José Anguizola
- Facultad de Ciencias de la Salud Dr. William C. Gorgas, Universidad Latina de Panamá, Panamá, Panamá
| | - Ricardo Lleonart
- Centro de Biología Celular y Molecular de Enfermedades, Instituto de Investigaciones Científicas y Servicios de Alta Tecnología (INDICASAT AIP), Ciudad del Saber, Panamá, Panamá
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Crystal structure and biophysical characterization of the nucleoside diphosphate kinase from Leishmania braziliensis. BMC STRUCTURAL BIOLOGY 2015; 15:2. [PMID: 25643978 PMCID: PMC4322457 DOI: 10.1186/s12900-015-0030-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Accepted: 01/15/2015] [Indexed: 01/07/2023]
Abstract
BACKGROUND Nucleoside diphosphate kinase (NDK) is a housekeeping enzyme that plays key roles in nucleotide recycling and homeostasis in trypanosomatids. It is also secreted by the intracellular parasite Leishmania to modulate the host response. These functions make NDK an attractive target for drug design and for studies aiming at a better understanding of the mechanisms mediating host-pathogen interactions. RESULTS We report the crystal structure and biophysical characterization of the NDK from Leishmania braziliensis (LbNDK). The subunit consists of six α-helices along with a core of four β-strands arranged in a β2β3β1β4 antiparallel topology order. In contrast to the NDK from L. major, the LbNDK C-terminal extension is partially unfolded. SAXS data showed that LbNDK forms hexamers in solution in the pH range from 7.0 to 4.0, a hydrodynamic behavior conserved in most eukaryotic NDKs. However, DSF assays show that acidification and alkalization decrease the hexamer stability. CONCLUSIONS Our results support that LbNDK remains hexameric in pH conditions akin to that faced by this enzyme when secreted by Leishmania amastigotes in the parasitophorous vacuoles (pH 4.7 to 5.3). The unusual unfolded conformation of LbNDK C-terminus decreases the surface buried in the trimer interface exposing new regions that might be explored for the development of compounds designed to disturb enzyme oligomerization, which may impair the important nucleotide salvage pathway in these parasites.
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Boswell-Casteel RC, Johnson JM, Duggan KD, Roe-Žurž Z, Schmitz H, Burleson C, Hays FA. FUN26 (function unknown now 26) protein from saccharomyces cerevisiae is a broad selectivity, high affinity, nucleoside and nucleobase transporter. J Biol Chem 2014; 289:24440-51. [PMID: 25035431 DOI: 10.1074/jbc.m114.553503] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Equilibrative nucleoside transporters (ENTs) are polytopic integral membrane proteins that transport nucleosides and, to a lesser extent, nucleobases across cell membranes. ENTs modulate efficacy for a range of human therapeutics and function in a diffusion-controlled bidirectional manner. A detailed understanding of ENT function at the molecular level has remained elusive. FUN26 (function unknown now 26) is a putative ENT homolog from S. cerevisiae that is expressed in vacuole membranes. In the present system, proteoliposome studies of purified FUN26 demonstrate robust nucleoside and nucleobase uptake into the luminal volume for a broad range of substrates. This transport activity is sensitive to nucleoside modifications in the C(2')- and C(5')-positions on the ribose sugar and is not stimulated by a membrane pH differential. [(3)H]Adenine nucleobase transport efficiency is increased ∼4-fold relative to nucleosides tested with no observed [(3)H]adenosine or [(3)H]UTP transport. FUN26 mutational studies identified residues that disrupt (G463A or G216A) or modulate (F249I or L390A) transporter function. These results demonstrate that FUN26 has a unique substrate transport profile relative to known ENT family members and that a purified ENT can be reconstituted in proteoliposomes for functional characterization in a defined system.
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Affiliation(s)
| | | | - Kelli D Duggan
- From the Department of Biochemistry and Molecular Biology and
| | - Zygy Roe-Žurž
- the Department of Biochemistry and Biophysics, University of California, San Francisco, California 94143
| | - Hannah Schmitz
- From the Department of Biochemistry and Molecular Biology and
| | - Carter Burleson
- From the Department of Biochemistry and Molecular Biology and
| | - Franklin A Hays
- From the Department of Biochemistry and Molecular Biology and the Stephenson Oklahoma Cancer Center, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104 and
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Metabolic reprogramming during purine stress in the protozoan pathogen Leishmania donovani. PLoS Pathog 2014; 10:e1003938. [PMID: 24586154 PMCID: PMC3937319 DOI: 10.1371/journal.ppat.1003938] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Accepted: 01/06/2014] [Indexed: 01/18/2023] Open
Abstract
The ability of Leishmania to survive in their insect or mammalian host is dependent upon an ability to sense and adapt to changes in the microenvironment. However, little is known about the molecular mechanisms underlying the parasite response to environmental changes, such as nutrient availability. To elucidate nutrient stress response pathways in Leishmania donovani, we have used purine starvation as the paradigm. The salvage of purines from the host milieu is obligatory for parasite replication; nevertheless, purine-starved parasites can persist in culture without supplementary purine for over three months, indicating that the response to purine starvation is robust and engenders parasite survival under conditions of extreme scarcity. To understand metabolic reprogramming during purine starvation we have employed global approaches. Whole proteome comparisons between purine-starved and purine-replete parasites over a 6–48 h span have revealed a temporal and coordinated response to purine starvation. Purine transporters and enzymes involved in acquisition at the cell surface are upregulated within a few hours of purine removal from the media, while other key purine salvage components are upregulated later in the time-course and more modestly. After 48 h, the proteome of purine-starved parasites is extensively remodeled and adaptations to purine stress appear tailored to deal with both purine deprivation and general stress. To probe the molecular mechanisms affecting proteome remodeling in response to purine starvation, comparative RNA-seq analyses, qRT-PCR, and luciferase reporter assays were performed on purine-starved versus purine-replete parasites. While the regulation of a minority of proteins tracked with changes at the mRNA level, for many regulated proteins it appears that proteome remodeling during purine stress occurs primarily via translational and/or post-translational mechanisms. Leishmania, the cause of a deadly spectrum of diseases in humans, surmounts a number of environmental challenges, including changes in the availability of salvageable nutrients, to successfully colonize its host. Adaptation to environmental stress is clearly of significance in parasite biology, but the underlying mechanisms are not well understood. To simulate the response to periodic nutrient scarcity in vivo, we have induced purine starvation in vitro. Purines are essential for growth and viability, and serve as the major energy currency of cells. Leishmania cannot synthesize purines and must salvage them from the surroundings. Extracellular purine depletion in culture induces a robust survival response in Leishmania, whereby growth arrests, but parasites persist for months. To profile the events that enable endurance of purine starvation, we used shotgun proteomics. Our data suggest that purine starvation induces extensive proteome remodeling, tailored to enhance purine capture and recycling, reduce energy expenditures, and maintain viability of the metabolically active, non-dividing population. Through global and targeted approaches, we reveal that proteome remodeling is multifaceted, and occurs through an array of responses at the mRNA, translational, and post-translational level. Our data provide one of the most inclusive views of adaptation to microenvironmental stress in Leishmania.
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Dean P, Major P, Nakjang S, Hirt RP, Embley TM. Transport proteins of parasitic protists and their role in nutrient salvage. FRONTIERS IN PLANT SCIENCE 2014; 5:153. [PMID: 24808897 PMCID: PMC4010794 DOI: 10.3389/fpls.2014.00153] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2014] [Accepted: 04/01/2014] [Indexed: 05/02/2023]
Abstract
The loss of key biosynthetic pathways is a common feature of important parasitic protists, making them heavily dependent on scavenging nutrients from their hosts. This is often mediated by specialized transporter proteins that ensure the nutritional requirements of the parasite are met. Over the past decade, the completion of several parasite genome projects has facilitated the identification of parasite transporter proteins. This has been complemented by functional characterization of individual transporters along with investigations into their importance for parasite survival. In this review, we summarize the current knowledge on transporters from parasitic protists and highlight commonalities and differences in the transporter repertoires of different parasitic species, with particular focus on characterized transporters that act at the host-pathogen interface.
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Affiliation(s)
- Paul Dean
- *Correspondence: Paul Dean and T. Martin Embley, The Medical School, Institute for Cell and Molecular Biosciences, Newcastle University, Catherine Cookson Building, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK e-mail: ;
| | | | | | | | - T. Martin Embley
- *Correspondence: Paul Dean and T. Martin Embley, The Medical School, Institute for Cell and Molecular Biosciences, Newcastle University, Catherine Cookson Building, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK e-mail: ;
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Zheng LL, Wen YZ, Yang JH, Liao JY, Shao P, Xu H, Zhou H, Wen JZ, Lun ZR, Ayala FJ, Qu LH. Comparative transcriptome analysis of small noncoding RNAs in different stages of Trypanosoma brucei. RNA (NEW YORK, N.Y.) 2013; 19:863-875. [PMID: 23704326 PMCID: PMC3683921 DOI: 10.1261/rna.035683.112] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/27/2012] [Accepted: 03/12/2013] [Indexed: 06/02/2023]
Abstract
Trypanosoma brucei, a pathogen of human and domestic animals, is an early evolved parasitic protozoan with a complex life cycle. Most genes of this parasite are post-transcriptionally regulated. However, the mechanisms and the molecules involved remain largely unknown. We have deep-sequenced the small RNAs of two life stages of this parasite--the bloodstream form and the procyclic form. Our results show that the small RNAs of T. brucei could derive from multiple sources, including NATs (natural antisense transcripts), tRNAs, and rRNAs. Most of these small RNAs in the two stages were found to share uniform characteristics. However, our results demonstrate that their variety and expression show significant differences between different stages, indicating possible functional differentiation. Dicer-knockdown evidence further proved that some of the small interfering RNAs (siRNAs) could regulate the expression of genes. Based on the genome-wide analysis of the small RNAs in the two stages of T. brucei, our results not only provide evidence to study their differentiation but also shed light on questions regarding the origins and evolution of small RNA-based mechanisms in early eukaryotes.
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MESH Headings
- Base Sequence
- Computational Biology
- Evolution, Molecular
- Gene Expression Profiling/methods
- Gene Expression Regulation
- Genes, Protozoan
- High-Throughput Nucleotide Sequencing
- Molecular Sequence Data
- RNA, Protozoan/genetics
- RNA, Protozoan/metabolism
- RNA, Small Interfering/genetics
- RNA, Small Interfering/metabolism
- RNA, Small Untranslated/genetics
- RNA, Small Untranslated/metabolism
- RNA, Transfer/genetics
- RNA, Transfer/metabolism
- Ribonuclease III/genetics
- Ribonuclease III/metabolism
- Trypanosoma brucei brucei/genetics
- Trypanosoma brucei brucei/metabolism
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Affiliation(s)
- Ling-Ling Zheng
- State Key Laboratory of Biocontrol, Key Laboratory of Gene Engineering, Ministry of Education, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China
| | - Yan-Zi Wen
- Key Laboratory of Tropical Disease and Control, Ministry of Education, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou 510080, China
| | - Jian-Hua Yang
- State Key Laboratory of Biocontrol, Key Laboratory of Gene Engineering, Ministry of Education, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China
| | - Jian-You Liao
- State Key Laboratory of Biocontrol, Key Laboratory of Gene Engineering, Ministry of Education, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China
| | - Peng Shao
- State Key Laboratory of Biocontrol, Key Laboratory of Gene Engineering, Ministry of Education, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China
| | - Hui Xu
- State Key Laboratory of Biocontrol, Key Laboratory of Gene Engineering, Ministry of Education, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China
| | - Hui Zhou
- State Key Laboratory of Biocontrol, Key Laboratory of Gene Engineering, Ministry of Education, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China
| | - Jun-Zhi Wen
- State Key Laboratory of Biocontrol, Key Laboratory of Gene Engineering, Ministry of Education, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China
| | - Zhao-Rong Lun
- State Key Laboratory of Biocontrol, Key Laboratory of Gene Engineering, Ministry of Education, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China
- Key Laboratory of Tropical Disease and Control, Ministry of Education, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou 510080, China
- Centre for Parasitology and Disease, School of Environment and Life Sciences, University of Salford, Salford M5 4WT, United Kingdom
| | - Francisco J. Ayala
- Department of Ecology and Evolutionary Biology, University of California, Irvine, California 92697, USA
| | - Liang-Hu Qu
- State Key Laboratory of Biocontrol, Key Laboratory of Gene Engineering, Ministry of Education, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China
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Allopurinol and xanthine use different translocation mechanisms and trajectories in the fungal UapA transporter. Biochimie 2013; 95:1755-64. [PMID: 23791789 DOI: 10.1016/j.biochi.2013.05.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Accepted: 05/31/2013] [Indexed: 01/14/2023]
Abstract
In Aspergillus nidulans UapA is a H(+)-driven transporter specific for xanthine, uric acid and several analogues. Here, genetic and physiological evidence is provided showing that allopurinol is a high-affinity, low-capacity, substrate for UapA. Surprisingly however, transport kinetic measurements showed that, uniquely among all recognized UapA substrates, allopurinol is transported by apparent facilitated diffusion and exhibits a paradoxical effect on the transport of physiological substrates. Specifically, excess xanthine or other UapA substrates inhibit allopurinol uptake, as expected, but the presence of excess allopurinol results in a concentration-dependent enhancement of xanthine binding and transport. Flexible docking approaches failed to detect allopurinol binding in the major UapA substrate binding site, which was recently identified by mutational analysis and substrate docking using all other UapA substrates. These results and genetic evidence suggest that the allopurinol translocation pathway is distinct from, but probably overlapping with, that of physiological UapA substrates. Furthermore, although the stimulating effect of allopurinol on xanthine transport could, in principle, be rationalized by a cryptic allopurinol-specific allosteric site, evidence was obtained supporting that accelerated influx of xanthine is triggered through exchange with cytoplasmically accumulated allopurinol. Our results are in line with recently accumulating evidence revealing atypical and complex mechanisms underlying transport systems.
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Ali JAM, Tagoe DNA, Munday JC, Donachie A, Morrison LJ, de Koning HP. Pyrimidine biosynthesis is not an essential function for Trypanosoma brucei bloodstream forms. PLoS One 2013; 8:e58034. [PMID: 23505454 PMCID: PMC3591441 DOI: 10.1371/journal.pone.0058034] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2012] [Accepted: 01/29/2013] [Indexed: 11/18/2022] Open
Abstract
Background African trypanosomes are capable of both pyrimidine biosynthesis and salvage of preformed pyrimidines from the host, but it is unknown whether either process is essential to the parasite. Methodology/Principal Findings Pyrimidine requirements for growth were investigated using strictly pyrimidine-free media, with or without single added pyrimidine sources. Growth rates of wild-type bloodstream form Trypanosoma brucei brucei were unchanged in pyrimidine-free medium. The essentiality of the de novo pyrimidine biosynthesis pathway was studied by knocking out the PYR6-5 locus that produces a fusion product of orotate phosphoribosyltransferase (OPRT) and Orotidine Monophosphate Decarboxylase (OMPDCase). The pyrimidine auxotroph was dependent on a suitable extracellular pyrimidine source. Pyrimidine starvation was rapidly lethal and non-reversible, causing incomplete DNA content in new cells. The phenotype could be rescued by addition of uracil; supplementation with uridine, 2′deoxyuridine, and cytidine allowed a diminished growth rate and density. PYR6-5−/− trypanosomes were more sensitive to pyrimidine antimetabolites and displayed increased uracil transport rates and uridine phosphorylase activity. Pyrimidine auxotrophs were able to infect mice although the infection developed much more slowly than infection with the parental, prototrophic trypanosome line. Conclusions/Significance Pyrimidine salvage was not an essential function for bloodstream T. b. brucei. However, trypanosomes lacking de novo pyrimidine biosynthesis are completely dependent on an extracellular pyrimidine source, strongly preferring uracil, and display reduced infectivity. As T. brucei are able to salvage sufficient pyrimidines from the host environment, the pyrimidine biosynthesis pathway is not a viable drug target, although any interruption of pyrimidine supply was lethal.
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Affiliation(s)
- Juma A. M. Ali
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
- Faculty of Science, Department of Zoology, Al Jabal Al Gharbi University, Gharyan, Libya
| | - Daniel N. A. Tagoe
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Jane C. Munday
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
- Wellcome Trust Centre for Molecular Parasitology, University of Glasgow, Glasgow, United Kingdom
| | - Anne Donachie
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Liam J. Morrison
- Wellcome Trust Centre for Molecular Parasitology, University of Glasgow, Glasgow, United Kingdom
- Roslin Institute, University of Edinburgh, Easter Bush, United Kingdom
| | - Harry P. de Koning
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
- * E-mail:
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Sinha DK, Atray I, Bentur JS, Nair S. Expression of Orseolia oryzae nucleoside diphosphate kinase (OoNDPK) is enhanced in rice gall midge feeding on susceptible rice hosts and its over-expression leads to salt tolerance in Escherichia coli. INSECT MOLECULAR BIOLOGY 2012; 21:593-603. [PMID: 23126268 DOI: 10.1111/j.1365-2583.2012.01163.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The Asian rice gall midge, Orseolia oryzae, is a major dipteran pest of rice, with many known biotypes. The present investigation was initiated to understand the molecular mechanisms of infestation for developing novel integrated pest management strategies. We isolated and characterized a gene, nucleoside diphosphate kinase (OoNDPK), from the rice gall midge, encoding a protein with 169 amino acid residues and with a secretory signal sequence - an observation that assumes significance as salivary gland secretions have been implicated to play a major role in insect-plant interactions. Furthermore, up-regulation (> 18 folds) of OoNDPK was observed in the salivary glands of maggots feeding on susceptible host in contrast to those feeding on resistant host. Phylogenetic analysis revealed similarity of OoNDPK with its dipteran orthologues. 3DLigandSite analysis, of the predicted OoNDPK and its orthologues, revealed phenylalanine and tyrosine residues to be specifically present in NDPK proteins from the plant feeders. Results suggest secretion of OoNDPK into the host plant and its probable involvement in gall midge-rice interaction. Using the coleoptile cell elongation assay, we demonstrated that the recombinant OoNDPK is capable of causing elongation of rice coleoptile cells. Additionally, heterologous expression of OoNDPK in Escherichia coli increased the tolerance of these cells to salt (NaCl; up to 1 mM), hinting at the involvement of this gene in abiotic stress response as well.
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Affiliation(s)
- D K Sinha
- Plant Molecular Biology Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
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Boitz JM, Ullman B, Jardim A, Carter NS. Purine salvage in Leishmania: complex or simple by design? Trends Parasitol 2012; 28:345-52. [PMID: 22726696 DOI: 10.1016/j.pt.2012.05.005] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2012] [Revised: 05/22/2012] [Accepted: 05/23/2012] [Indexed: 11/19/2022]
Abstract
Purine nucleotides function in a variety of vital cellular and metabolic processes including energy production, cell signaling, synthesis of vitamin-derived cofactors and nucleic acids, and as determinants of cell fate. Unlike their mammalian and insect hosts, Leishmania cannot synthesize the purine ring de novo and are absolutely dependent upon them to meet their purine requirements. The obligatory nature of purine salvage in these parasites, therefore, offers an attractive paradigm for drug targeting and, consequently, the delineation of the pathway has been under scientific investigation for over 30 years. Here, we review recent developments that reveal how purines flux in Leishmania and offer a potential 'Achilles' heel' for future validation.
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Affiliation(s)
- Jan M Boitz
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University, Portland, OR 97239, USA.
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Ranjbarian F, Vodnala M, Vodnala SM, Rofougaran R, Thelander L, Hofer A. Trypanosoma brucei thymidine kinase is tandem protein consisting of two homologous parts, which together enable efficient substrate binding. J Biol Chem 2012; 287:17628-17636. [PMID: 22442154 DOI: 10.1074/jbc.m112.340059] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Trypanosoma brucei causes African sleeping sickness, a disease for which existing chemotherapies are limited by their toxicity or lack of efficacy. We have found that four parasites, including T. brucei, contain genes where two or four thymidine kinase (TK) sequences are fused into a single open reading frame. The T. brucei full-length enzyme as well as its two constituent parts, domain 1 and domain 2, were separately expressed and characterized. Of potential interest for nucleoside analog development, T. brucei TK was less discriminative against purines than human TK1 with the following order of catalytic efficiencies: thymidine > deoxyuridine ≫ deoxyinosine > deoxyguanosine. Proteins from the TK1 family are generally dimers or tetramers, and the quaternary structure is linked to substrate affinity. T. brucei TK was primarily monomeric but can be considered a two-domain pseudodimer. Independent kinetic analysis of the two domains showed that only domain 2 was active. It had a similar turnover number (k(cat)) as the full-length enzyme but could not self-dimerize efficiently and had a 5-fold reduced thymidine/deoxyuridine affinity. Domain 1, which lacks three conserved active site residues, can therefore be considered a covalently attached structural partner that enhances substrate binding to domain 2. A consequence of the non-catalytic role of domain 1 is that its active site residues are released from evolutionary pressure, which can be advantageous for developing new catalytic functions. In addition, nearly identical 89-bp sequences present in both domains suggest that the exchange of genetic material between them can further promote evolution.
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Affiliation(s)
- Farahnaz Ranjbarian
- Department of Medical Biochemistry and Biophysics, Umeå University, SE-901 87 Umeå, Sweden
| | - Munender Vodnala
- Department of Medical Biochemistry and Biophysics, Umeå University, SE-901 87 Umeå, Sweden
| | | | - Reza Rofougaran
- Department of Medical Biochemistry and Biophysics, Umeå University, SE-901 87 Umeå, Sweden; Department of Biochemistry, Institute of Biochemistry and Biophysics, P.O. Box 13145-1384, Tehran University, Tehran, Iran
| | - Lars Thelander
- Department of Medical Biochemistry and Biophysics, Umeå University, SE-901 87 Umeå, Sweden
| | - Anders Hofer
- Department of Medical Biochemistry and Biophysics, Umeå University, SE-901 87 Umeå, Sweden.
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McConville MJ, Naderer T. Metabolic pathways required for the intracellular survival of Leishmania. Annu Rev Microbiol 2012; 65:543-61. [PMID: 21721937 DOI: 10.1146/annurev-micro-090110-102913] [Citation(s) in RCA: 101] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Leishmania spp. are sandfly-transmitted parasitic protozoa that cause a spectrum of important diseases and lifelong chronic infections in humans. In the mammalian host, these parasites proliferate within acidified vacuoles in several phagocytic host cells, including macrophages, dendritic cells, and neutrophils. In this review, we discuss recent progress that has been made in defining the nutrient composition of the Leishmania parasitophorous vacuole, as well as metabolic pathways required by these parasites for virulence. Analysis of the virulence phenotype of Leishmania mutants has been particularly useful in defining carbon sources and nutrient salvage pathways that are essential for parasite persistence and/or induction of pathology. We also review data suggesting that intracellular parasite stages modulate metabolic processes in their host cells in order to generate a more permissive niche.
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Affiliation(s)
- Malcolm J McConville
- Department of Biochemistry and Molecular Biology, University of Melbourne, Bio21 Institute of Molecular Science and Biotechnology, Parkville, Victoria 3010, Australia.
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Silva AM, Cordeiro-da-Silva A, Coombs GH. Metabolic variation during development in culture of Leishmania donovani promastigotes. PLoS Negl Trop Dis 2011; 5:e1451. [PMID: 22206037 PMCID: PMC3243725 DOI: 10.1371/journal.pntd.0001451] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2011] [Accepted: 11/10/2011] [Indexed: 11/28/2022] Open
Abstract
The genome sequencing of several Leishmania species has provided immense amounts of data and allowed the prediction of the metabolic pathways potentially operating. Subsequent genetic and proteomic studies have identified stage-specific proteins and putative virulence factors but many aspects of the metabolic adaptations of Leishmania remain to be elucidated. In this study, we have used an untargeted metabolomics approach to analyze changes in the metabolite profile as promastigotes of L. donovani develop during in vitro cultures from logarithmic to stationary phase. The results show that the metabolomes of promastigotes on days 3–6 of culture differ significantly from each other, consistent with there being distinct developmental changes. Most notable were the structural changes in glycerophospholipids and increase in the abundance of sphingolipids and glycerolipids as cells progress from logarithmic to stationary phase. Leishmania infections are considered neglected tropical diseases as the parasites affect millions of people worldwide but there are limited research efforts aimed at obtaining vaccines and new drugs. Leishmania has a digenetic life cycle alternating between promastigote forms, which develop in the sand-fly, the vector of the disease, and an amastigote form, which grows in mammals after being bitten by an infected sand-fly. In vitro studies with the promastigote forms are routinely used to gain insights about the parasite's cell biology. Little is known about how the different promastigotes forms are metabolically adapted to their particular micro-environment in the host or how they are pre-adapted metabolically for infecting a mammal, thus we have undertaken a study of the metabolite profile of L. donovani promastigotes in order to gain an understanding of the changes that occur during promastigote development. The analysis has revealed that the changes in promastigotes' metabolome between days 3 and 6 take place in a progressive manner; however major differences were observed when comparing the promastigotes on days 3 and 6. An increase in lipid abundance as promastigote development occurred was notable and is likely to reflect remodelling of the parasite's surface in readiness for infecting a mammal.
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Affiliation(s)
- Ana Marta Silva
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, United Kingdom
- Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
- Laboratório de Ciências Biológicas, Faculdade de Farmácia da Universidade do Porto, Porto, Portugal
| | - Anabela Cordeiro-da-Silva
- Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
- Laboratório de Ciências Biológicas, Faculdade de Farmácia da Universidade do Porto, Porto, Portugal
| | - Graham H. Coombs
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, United Kingdom
- * E-mail:
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Yao SYM, Ng AML, Cass CE, Baldwin SA, Young JD. Nucleobase transport by human equilibrative nucleoside transporter 1 (hENT1). J Biol Chem 2011; 286:32552-62. [PMID: 21795683 DOI: 10.1074/jbc.m111.236117] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The human equilibrative nucleoside transporters hENT1 and hENT2 (each with 456 residues) are 40% identical in amino acid sequence and contain 11 putative transmembrane helices. Both transport purine and pyrimidine nucleosides and are distinguished functionally by a difference in sensitivity to inhibition by nanomolar concentrations of nitrobenzylmercaptopurine ribonucleoside (NBMPR), hENT1 being NBMPR-sensitive. Previously, we used heterologous expression in Xenopus oocytes to demonstrate that recombinant hENT2 and its rat ortholog rENT2 also transport purine and pyrimidine bases, h/rENT2 representing the first identified mammalian nucleobase transporter proteins (Yao, S. Y., Ng, A. M., Vickers, M. F., Sundaram, M., Cass, C. E., Baldwin, S. A., and Young, J. D. (2002) J. Biol. Chem. 277, 24938-24948). The same study also revealed lower, but significant, transport of hypoxanthine by h/rENT1. In the present investigation, we have used the enhanced Xenopus oocyte expression vector pGEMHE to demonstrate that hENT1 additionally transports thymine and adenine and, to a lesser extent, uracil and guanine. Fluxes of hypoxanthine, thymine, and adenine by hENT1 were saturable and inhibited by NBMPR. Ratios of V(max) (pmol/oocyte · min(-1)):K(m) (mm), a measure of transport efficiency, were 86, 177, and 120 for hypoxantine, thymine, and adenine, respectively, compared with 265 for uridine. Hypoxanthine influx was competitively inhibited by uridine, indicating common or overlapping nucleobase and nucleoside permeant binding pockets, and the anticancer nucleobase drugs 5-fluorouracil and 6-mercaptopurine were also transported. Nucleobase transport activity was absent from an engineered cysteine-less version hENT1 (hENT1C-) in which all 10 endogenous cysteine residues were mutated to serine. Site-directed mutagenesis identified Cys-414 in transmembrane helix 10 of hENT1 as the residue conferring nucleobase transport activity to the wild-type transporter.
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Affiliation(s)
- Sylvia Y M Yao
- Membrane Protein Disease Research Group, Department of Physiology, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
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Abstract
BACKGROUND Nucleoside/nucleobase transporters have been investigated since the 1960s. In particular, equilibrative nucleoside transporters were thought to be valuable drug targets, since they are involved in various kinds of viral and parasitic diseases as well as cancers. DISCUSSION In the postgenomic era multiple transporters, including different subtypes, have been cloned and characterized on the molecular level. In this article we summarize recent advances regarding structure, function and localization of nucleoside/nucleobase transporters as well as the pharmacological profile of selected drugs. CONCLUSION Knowledge of the different kinetic properties and structural features of nucleoside transporters can either be used for the rational design of therapeutics directly targeting the transporter itself or for the delivery of drugs using the transporter as a port of entry into the target cell. Equilibrative nucleoside transporters are of considerable pharmacological interest as drug targets for the development of drugs tailored to each patient's need for the treatment of cardiac disease, cancer and viral infections.
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Souza TACB, Trindade DM, Tonoli CCC, Santos CR, Ward RJ, Arni RK, Oliveira AHC, Murakami MT. Molecular adaptability of nucleoside diphosphate kinase b from trypanosomatid parasites: stability, oligomerization and structural determinants of nucleotide binding. MOLECULAR BIOSYSTEMS 2011; 7:2189-95. [PMID: 21528129 DOI: 10.1039/c0mb00307g] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Nucleoside diphosphate kinases play a crucial role in the purine-salvage pathway of trypanosomatid protozoa and have been found in the secretome of Leishmania sp., suggesting a function related to host-cell integrity for the benefit of the parasite. Due to their importance for housekeeping functions in the parasite and by prolonging the life of host cells in infection, they become an attractive target for drug discovery and design. In this work, we describe the first structural characterization of nucleoside diphosphate kinases b from trypanosomatid parasites (tNDKbs) providing insights into their oligomerization, stability and structural determinants for nucleotide binding. Crystallographic studies of LmNDKb when complexed with phosphate, AMP and ADP showed that the crucial hydrogen-bonding residues involved in the nucleotide interaction are fully conserved in tNDKbs. Depending on the nature of the ligand, the nucleotide-binding pocket undergoes conformational changes, which leads to different cavity volumes. SAXS experiments showed that tNDKbs, like other eukaryotic NDKs, form a hexamer in solution and their oligomeric state does not rely on the presence of nucleotides or mimetics. Fluorescence-based thermal-shift assays demonstrated slightly higher stability of tNDKbs compared to human NDKb (HsNDKb), which is in agreement with the fact that tNDKbs are secreted and subjected to variations of temperature in the host cells during infection and disease development. Moreover, tNDKbs were stabilized upon nucleotide binding, whereas HsNDKb was not influenced. Contrasts on the surface electrostatic potential around the nucleotide-binding pocket might be a determinant for nucleotide affinity and protein stability differentiation. All these together demonstrated the molecular adaptation of parasite NDKbs in order to exert their biological functions intra-parasite and when secreted by regulating ATP levels of host cells.
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Affiliation(s)
- Tatiana A C B Souza
- Laboratório Nacional de Biociências, Laboratório Nacional de Luz Síncrotron, Centro Nacional de Pesquisa em Energia e Materiais, Campinas, SP, Brazil.
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45
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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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Corrales RCNR, de Souza NB, Pinheiro LS, Abramo C, Coimbra ES, Da Silva AD. Thiopurine derivatives containing triazole and steroid: synthesis, antimalarial and antileishmanial activities. Biomed Pharmacother 2010; 65:198-203. [PMID: 21111565 DOI: 10.1016/j.biopha.2010.10.013] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2010] [Accepted: 10/12/2010] [Indexed: 11/25/2022] Open
Abstract
A series of novel 6-thiopurine derivates containing 1,2,3-triazole were synthesized and their in vivo antimalarial activity and in vitro antileishmanial activity were examined. The compounds 10, 11, 12 and 14 presented higher values of inhibition of parasite multiplication than chloroquine. For antileishmanial activity, the compound 14 showed activity against the three species of Leishmania tested. None of compounds showed cytotoxicity against mammalian cells.
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Affiliation(s)
- Roberta C N R Corrales
- Departamento de Química, ICE, Universidade Federal de Juiz de Fora, Campus Universitário, Juiz de Fora, Minas Gerais 36036-900, Brazil
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47
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Möhlmann T, Bernard C, Hach S, Ekkehard Neuhaus H. Nucleoside transport and associated metabolism. PLANT BIOLOGY (STUTTGART, GERMANY) 2010; 12 Suppl 1:26-34. [PMID: 20712618 DOI: 10.1111/j.1438-8677.2010.00351.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Nucleosides are intermediates of nucleotide metabolism. Nucleotide de novo synthesis generates the nucleoside monophosphates AMP and UMP, which are further processed to all purine and pyrimidine nucleotides involved in multiple cellular reactions, including the synthesis of nucleic acids. Catabolism of these substances results in the formation of nucleosides, which are further degraded by nucleoside hydrolase to nucleobases. Both nucleosides and nucleobases can be exchanged between cells and tissues through multiple isoforms of corresponding transport proteins. After uptake into a cell, nucleosides and nucleobases can undergo salvage reactions or catabolism. Whereas energy is preserved by salvage pathway reactions, catabolism liberates ammonia, which is then incorporated into amino acids. Keeping the balance between nitrogen consumption during nucleotide de novo synthesis and ammonia liberation by nucleotide catabolism is essential for correct plant development. Senescence and seed germination represent situations in plant development where marked fluctuations in nucleotide pools occur. Furthermore, extracellular nucleotide metabolism has become an immensely interesting research topic. In addition, selected aspects of nucleoside transport in yeast, protists and humans are discussed.
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Affiliation(s)
- T Möhlmann
- Abteilung Pflanzenphysiologie, Fachbereich Biologie, Technische Universität Kaiserslautern, Kaiserslautern, Germany.
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48
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Ortiz D, Valdés R, Sanchez MA, Hayenga J, Elya C, Detke S, Landfear SM. Purine restriction induces pronounced translational upregulation of the NT1 adenosine/pyrimidine nucleoside transporter in Leishmania major. Mol Microbiol 2010; 78:108-18. [PMID: 20735779 DOI: 10.1111/j.1365-2958.2010.07328.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Leishmania and other parasitic protozoa are unable to synthesize purines de novo and are reliant upon purine nucleoside and nucleobase transporters to import preformed purines from their hosts. To study the roles of the four purine permeases NT1-NT4 in Leishmania major, null mutants in each transporter gene were prepared and the effect of each gene deletion on purine uptake was monitored. Deletion of the NT3 purine nucleobase transporter gene or both NT3 and the NT2 nucleoside transporter gene resulted in pronounced upregulation of adenosine and uridine uptake mediated by the NT1 permease and also induced up to a 200-fold enhancement in the level of the NT1 protein but not mRNA. A similar level of upregulation of NT1 was achieved in wild-type promastigotes that were transferred to medium deficient in purines. Pulse labelling and treatment of cells with the translation inhibitor cycloheximide revealed that control of NT1 expression occurs primarily at the level of translation and not protein turnover. These observations imply the existence of a translational control mechanism that enhances the ability of Leishmania parasites to import essential purines when they are present at limiting concentrations.
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Affiliation(s)
- Diana Ortiz
- Department of Molecular Microbiology and Immunology, Oregon Health and Science University, Portland, OR 97239, USA
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Dridi L, Ahmed Ouameur A, Ouellette M. High affinity S-Adenosylmethionine plasma membrane transporter of Leishmania is a member of the folate biopterin transporter (FBT) family. J Biol Chem 2010; 285:19767-75. [PMID: 20406813 PMCID: PMC2888387 DOI: 10.1074/jbc.m110.114520] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2010] [Revised: 04/12/2010] [Indexed: 11/06/2022] Open
Abstract
S-Adenosylmethionine (AdoMet) is an important methyl group donor that plays a central role in many essential biochemical processes. The parasite Leishmania can both synthesize and transport AdoMet. Leishmania cells resistant to the antifolate methotrexate due to a rearrangement in folate biopterin transporter (FBT) genes were cross-resistant to sinefungin, an AdoMet analogue. FBT gene rearrangements were also observed in Leishmania major cells selected for sinefungin resistance. One of the rearranged FBT genes corresponded to the main AdoMet transporter (AdoMetT1) of Leishmania as determined by gene transfection and gene inactivation experiments. AdoMetT1 was determined to be a high affinity plasma membrane transporter expressed constitutively throughout the growth phases of the parasite. Leishmania cells selected for resistance or naturally insensitive to sinefungin had lower expression of AdoMetT1. A new function in one carbon metabolism, also a pathway of interest for chemotherapeutic interventions, is described for a novel class of membrane proteins found in diverse organisms.
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Affiliation(s)
- Larbi Dridi
- From the Centre de Recherche en Infectiologie du CHUL, Université Laval, Québec City, Québec G1V 4G2, Canada
| | - Amin Ahmed Ouameur
- From the Centre de Recherche en Infectiologie du CHUL, Université Laval, Québec City, Québec G1V 4G2, Canada
| | - Marc Ouellette
- From the Centre de Recherche en Infectiologie du CHUL, Université Laval, Québec City, Québec G1V 4G2, Canada
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50
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Riegelhaupt PM, Frame IJ, Akabas MH. Transmembrane segment 11 appears to line the purine permeation pathway of the Plasmodium falciparum equilibrative nucleoside transporter 1 (PfENT1). J Biol Chem 2010; 285:17001-10. [PMID: 20335165 DOI: 10.1074/jbc.m110.115758] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Purine transport is essential for malaria parasites to grow because they lack the enzymes necessary for de novo purine biosynthesis. The Plasmodium falciparum Equilibrative Nucleoside Transporter 1 (PfENT1) is a member of the equilibrative nucleoside transporter (ENT) gene family. PfENT1 is a primary purine transport pathway across the P. falciparum plasma membrane because PfENT1 knock-out parasites are not viable at physiologic extracellular purine concentrations. Topology predictions and experimental data indicate that ENT family members have eleven transmembrane (TM) segments although their tertiary structure is unknown. In the current work, we showed that a naturally occurring polymorphism, F394L, in TM11 affects transport substrate K(m). We investigated the structure and function of the TM11 segment using the substituted cysteine accessibility method. We showed that mutation to Cys of two highly conserved glycine residues in a GXXXG motif significantly reduces PfENT1 protein expression levels. We speculate that the conserved TM11 GXXXG glycines may be critical for folding and/or assembly. Small, cysteine-specific methanethiosulfonate (MTS) reagents reacted with four TM11 Cys substitution mutants, L393C, I397C, T400C, and Y403C. Larger MTS reagents do not react with the more cytoplasmic positions. Hypoxanthine, a transported substrate, protected L393C, I397C, and T400C from covalent modification by the MTS reagents. Plotted on an alpha-helical wheel, Leu-393, Ile-397, and Thr-400 lie on one face of the helix in a 60 degrees arc suggesting that TM11 is largely alpha helical. We infer that they line a water-accessible surface, possibly the purine permeation pathway. These results advance our understanding of the ENT structure.
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Affiliation(s)
- Paul M Riegelhaupt
- Department of Physiology and Biophysics, Albert Einstein College of Medicine of Yeshiva University, Bronx, New York 10461, USA
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