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Basu S, Pawlowic MC, Hsu FF, Thomas G, Zhang K. Ethanolaminephosphate cytidylyltransferase is essential for survival, lipid homeostasis and stress tolerance in Leishmania major. PLoS Pathog 2023; 19:e1011112. [PMID: 37506172 PMCID: PMC10411802 DOI: 10.1371/journal.ppat.1011112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Revised: 08/09/2023] [Accepted: 07/12/2023] [Indexed: 07/30/2023] Open
Abstract
Glycerophospholipids including phosphatidylethanolamine (PE) and phosphatidylcholine (PC) are vital components of biological membranes. Trypanosomatid parasites of the genus Leishmania can acquire PE and PC via de novo synthesis and the uptake/remodeling of host lipids. In this study, we investigated the ethanolaminephosphate cytidylyltransferase (EPCT) in Leishmania major, which is the causative agent for cutaneous leishmaniasis. EPCT is a key enzyme in the ethanolamine branch of the Kennedy pathway which is responsible for the de novo synthesis of PE. Our results demonstrate that L. major EPCT is a cytosolic protein capable of catalyzing the formation of CDP-ethanolamine from ethanolamine-phosphate and cytidine triphosphate. Genetic manipulation experiments indicate that EPCT is essential in both the promastigote and amastigote stages of L. major as the chromosomal null mutants cannot survive without the episomal expression of EPCT. This differs from our previous findings on the choline branch of the Kennedy pathway (responsible for PC synthesis) which is required only in promastigotes but not amastigotes. While episomal EPCT expression does not affect promastigote proliferation under normal conditions, it leads to reduced production of ethanolamine plasmalogen or plasmenylethanolamine, the dominant PE subtype in Leishmania. In addition, parasites with episomal EPCT exhibit heightened sensitivity to acidic pH and starvation stress, and significant reduction in virulence. In summary, our investigation demonstrates that proper regulation of EPCT expression is crucial for PE synthesis, stress response, and survival of Leishmania parasites throughout their life cycle.
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Affiliation(s)
- Somrita Basu
- Department of Biological Sciences, Texas Tech University, Lubbock, Texas, United States of America
| | - Mattie C. Pawlowic
- Department of Biological Sciences, Texas Tech University, Lubbock, Texas, United States of America
- Wellcome Centre for Anti-Infectives Research (WCAIR), Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Fong-Fu Hsu
- Mass Spectrometry Resource, Division of Endocrinology, Metabolism, and Lipid Research, Department of Medicine, Washington University School of Medicine, Saint Louis, Missouri, United States of America
| | - Geoff Thomas
- Department of Biological Sciences, Texas Tech University, Lubbock, Texas, United States of America
| | - Kai Zhang
- Department of Biological Sciences, Texas Tech University, Lubbock, Texas, United States of America
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2
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Ren B, Liang X, Brouwers JF, Miron RC, Shen B, Gupta N. Synthesis vs. salvage of ester- and ether-linked phosphatidylethanolamine in the intracellular protozoan pathogen Toxoplasma gondii. Commun Biol 2023; 6:306. [PMID: 36949328 PMCID: PMC10033509 DOI: 10.1038/s42003-023-04664-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2022] [Accepted: 03/06/2023] [Indexed: 03/24/2023] Open
Abstract
Toxoplasma gondii is a prevalent zoonotic pathogen infecting livestock as well as humans. The exceptional ability of this parasite to reproduce in several types of nucleated host cells necessitates a coordinated usage of endogenous and host-derived nutritional resources for membrane biogenesis. Phosphatidylethanolamine is the second most common glycerophospholipid in T. gondii, but how its requirement in the acutely-infectious fast-dividing tachyzoite stage is satisfied remains enigmatic. This work reveals that the parasite deploys de novo synthesis and salvage pathways to meet its demand for ester- and ether-linked PtdEtn. Auxin-mediated depletion of the phosphoethanolamine cytidylyltransferase (ECT) caused a lethal phenotype in tachyzoites due to impaired invasion and cell division, disclosing a vital role of the CDP-ethanolamine pathway during the lytic cycle. In accord, the inner membrane complex appeared disrupted concurrent with a decline in its length, parasite width and major phospholipids. Integrated lipidomics and isotope analyses of the TgECT mutant unveiled the endogenous synthesis of ester-PtdEtn, and salvage of ether-linked lipids from host cells. In brief, this study demonstrates how T. gondii operates various means to produce distinct forms of PtdEtn while featuring the therapeutic relevance of its de novo synthesis.
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Affiliation(s)
- Bingjian Ren
- Department of Molecular Parasitology, Faculty of Life Sciences, Humboldt University, Berlin, Germany
| | - Xiaohan Liang
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
| | - Jos F Brouwers
- Research Group for Analysis Techniques in the Life Sciences, School of Life Sciences and Technology, Avans University of Applied Sciences, Breda, The Netherlands
| | - Rosalba Cruz Miron
- Intracellular Parasite Education and Research Labs (iPEARL), Department of Biological Sciences, Birla Institute of Technology and Science, Pilani (BITS-P), Hyderabad, India
| | - Bang Shen
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China.
| | - Nishith Gupta
- Department of Molecular Parasitology, Faculty of Life Sciences, Humboldt University, Berlin, Germany.
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China.
- Intracellular Parasite Education and Research Labs (iPEARL), Department of Biological Sciences, Birla Institute of Technology and Science, Pilani (BITS-P), Hyderabad, India.
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3
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Cerone M, Roberts M, Smith TK. The lipidome of Crithidia fasiculataand its plasticity. Front Cell Infect Microbiol 2022; 12:945750. [DOI: 10.3389/fcimb.2022.945750] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Accepted: 09/13/2022] [Indexed: 11/13/2022] Open
Abstract
Crithidia fasiculata belongs to the trypanosomatidae order of protozoan parasites, bearing close relation to other kinetoplastid parasites such as Trypanosoma brucei and Leishmania spp. As an early diverging lineage of eukaryotes, the study of kinetoplastid parasites has provided unique insights into alternative mechanisms to traditional eukaryotic metabolic pathways. Crithidia are a monogenetic parasite for mosquito species and have two distinct lifecycle stages both taking place in the mosquito gut. These consist of a motile choanomastigote form and an immotile amastigote form morphologically similar to amastigotes in Leishmania. Owing to their close relation to Leishmania, Crithidia are a growing research tool, with continuing interest in its use as a model organism for kinetoplastid research with the added benefit that they are non-pathogenic to humans and can be grown with no special equipment or requirements for biological containment. Although comparatively little research has taken place on Crithidia, similarities to other kinetoplast species has been shown in terms of energy metabolism and genetics. Crithidia also show similarities to kinetoplastids in their production of the monosaccharide D-arabinopyranose similar to Leishmania, which is incorporated into a lipoarabinogalactan a major cell surface GPI-anchored molecule. Additionally, Crithidia have been used as a eukaryotic expression system to express proteins from other kinetoplastids and potentially other eukaryotes including human proteins allowing various co- and post-translational protein modifications to the recombinant proteins. Despite the obvious usefulness and potential of this organism very little is known about its lipid metabolism. Here we describe a detailed lipidomic analyses and demonstrate the possible placidity of Crithidia’s lipid metabolis. This could have important implications for biotechnology approaches and how other kinetoplastids interact with, and scavenge nutrients from their hosts.
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Parreira de Aquino G, Mendes Gomes MA, Köpke Salinas R, Laranjeira-Silva MF. Lipid and fatty acid metabolism in trypanosomatids. MICROBIAL CELL 2021; 8:262-275. [PMID: 34782859 PMCID: PMC8561143 DOI: 10.15698/mic2021.11.764] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 09/03/2021] [Accepted: 09/13/2021] [Indexed: 12/18/2022]
Abstract
Trypanosomiases and leishmaniases are neglected tropical diseases that have been spreading to previously non-affected areas in recent years. Identification of new chemotherapeutics is needed as there are no vaccines and the currently available treatment options are highly toxic and often ineffective. The causative agents for these diseases are the protozoan parasites of the Trypanosomatidae family, and they alternate between invertebrate and vertebrate hosts during their life cycles. Hence, these parasites must be able to adapt to different environments and compete with their hosts for several essential compounds, such as amino acids, vitamins, ions, carbohydrates, and lipids. Among these nutrients, lipids and fatty acids (FAs) are essential for parasite survival. Trypanosomatids require massive amounts of FAs, and they can either synthesize FAs de novo or scavenge them from the host. Moreover, FAs are the major energy source during specific life cycle stages of T. brucei, T. cruzi, and Leishmania. Therefore, considering the distinctive features of FAs metabolism in trypanosomatids, these pathways could be exploited for the development of novel antiparasitic drugs. In this review, we highlight specific aspects of lipid and FA metabolism in the protozoan parasites T. brucei, T. cruzi, and Leishmania spp., as well as the pathways that have been explored for the development of new chemotherapies.
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Affiliation(s)
| | | | - Roberto Köpke Salinas
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, São Paulo, Brazil
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5
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Moitra S, Basu S, Pawlowic M, Hsu FF, Zhang K. De Novo Synthesis of Phosphatidylcholine Is Essential for the Promastigote But Not Amastigote Stage in Leishmania major. Front Cell Infect Microbiol 2021; 11:647870. [PMID: 33777852 PMCID: PMC7996062 DOI: 10.3389/fcimb.2021.647870] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Accepted: 02/09/2021] [Indexed: 12/18/2022] Open
Abstract
Phosphatidylcholine (PC) is the most abundant type of phospholipids in eukaryotes constituting ~30% of total lipids in Leishmania. PC synthesis mainly occurs via the choline branch of the Kennedy pathway (choline ⇒ choline-phosphate ⇒ CDP-choline ⇒ PC) and the N-methylation of phosphatidylethanolamine (PE). In addition, Leishmania parasites can acquire PC and other lipids from the host or culture medium. In this study, we assessed the function and essentiality of choline ethanolamine phosphotransferase (CEPT) in Leishmania major which is responsible for the final step of the de novo synthesis of PC and PE. Our data indicate that CEPT is localized in the endoplasmic reticulum and possesses the activity to generate PC from CDP-choline and diacylglycerol. Targeted deletion of CEPT is only possible in the presence of an episomal CEPT gene in the promastigote stage of L. major. These chromosomal null parasites require the episomal expression of CEPT to survive in culture, confirming its essentiality during the promastigote stage. In contrast, during in vivo infection of BALB/c mice, these chromosomal null parasites appeared to lose the episomal copy of CEPT while maintaining normal levels of virulence, replication and cellular PC. Therefore, while the de novo synthesis of PC/PE is indispensable for the proliferation of promastigotes, intracellular amastigotes appear to acquire most of their lipids through salvage and remodeling.
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Affiliation(s)
- Samrat Moitra
- Department of Biological Sciences, Texas Tech University, Lubbock, TX, United States
| | - Somrita Basu
- Department of Biological Sciences, Texas Tech University, Lubbock, TX, United States
| | - Mattie Pawlowic
- Department of Biological Sciences, Texas Tech University, Lubbock, TX, United States
| | - Fong-Fu Hsu
- Mass Spectrometry Resource, Division of Endocrinology, Diabetes, Metabolism, and Lipid research, Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO, United States
| | - Kai Zhang
- Department of Biological Sciences, Texas Tech University, Lubbock, TX, United States
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6
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Guidi A, Petrella G, Fustaino V, Saccoccia F, Lentini S, Gimmelli R, Di Pietro G, Bresciani A, Cicero DO, Ruberti G. Drug effects on metabolic profiles of Schistosoma mansoni adult male parasites detected by 1H-NMR spectroscopy. PLoS Negl Trop Dis 2020; 14:e0008767. [PMID: 33044962 PMCID: PMC7580944 DOI: 10.1371/journal.pntd.0008767] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 10/22/2020] [Accepted: 09/02/2020] [Indexed: 11/25/2022] Open
Abstract
Schistosomiasis is one of the most devastating neglected tropical parasitic diseases caused by trematodes of the genus Schistosoma. Praziquantel (PZQ) is today the only drug used in humans and animals for the treatment of schistosomiasis but unfortunately it is poorly effective on larval and juvenile stages of the parasite. Therefore, it is urgent the discovery of new drug targets and compounds. We have recently showed that the anti-anginal drug perhexiline maleate (PHX) is very active on multiple developmental stages of Schistosoma mansoni in vitro. It is well known that PHX impacts the lipid metabolism in mammals, but the final target on schistosomes still remains unknown. The aim of this study was to evaluate the ability of 1H nuclear magnetic resonance (NMR) spectroscopy in revealing metabolic perturbations due to PHX treatment of S. mansoni adult male worms. The effects of PHX were compared with the ones induced by vehicle and gambogic acid, in order to detect different metabolic profiles and specificity of the PHX action. Remarkably a list of metabolites associated to PHX-treatment was identified with enrichment in several connected metabolic pathways including also the Kennedy pathway mediating the glycerophospholipid metabolism. Our study represents the first 1H-NMR metabolomic approach to characterize the response of S. mansoni to drug treatment. The obtained "metabolic fingerprint" associated to PHX treatment could represent a strategy for displaying cellular metabolic changes for any given drug and to compare compounds targeting similar or distinct biochemical pathways.
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Affiliation(s)
- Alessandra Guidi
- Institute of Biochemistry and Cell Biology, National Research Council, Campus A. Buzzati-Traverso, Monterotondo (Rome) Italy
| | - Greta Petrella
- Department of Chemical Science and Technologies, University of Rome Tor Vergata, Rome, Italy
| | - Valentina Fustaino
- Institute of Biochemistry and Cell Biology, National Research Council, Campus A. Buzzati-Traverso, Monterotondo (Rome) Italy
| | - Fulvio Saccoccia
- Institute of Biochemistry and Cell Biology, National Research Council, Campus A. Buzzati-Traverso, Monterotondo (Rome) Italy
| | - Sara Lentini
- Department of Translational Biology, IRBM Science Park Spa, Pomezia (Rome), Italy
| | - Roberto Gimmelli
- Institute of Biochemistry and Cell Biology, National Research Council, Campus A. Buzzati-Traverso, Monterotondo (Rome) Italy
| | - Giulia Di Pietro
- Department of Chemical Science and Technologies, University of Rome Tor Vergata, Rome, Italy
| | - Alberto Bresciani
- Department of Translational Biology, IRBM Science Park Spa, Pomezia (Rome), Italy
| | - Daniel Oscar Cicero
- Department of Chemical Science and Technologies, University of Rome Tor Vergata, Rome, Italy
| | - Giovina Ruberti
- Institute of Biochemistry and Cell Biology, National Research Council, Campus A. Buzzati-Traverso, Monterotondo (Rome) Italy
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7
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Booth LA, Smith TK. Lipid metabolism in Trypanosoma cruzi: A review. Mol Biochem Parasitol 2020; 240:111324. [PMID: 32961207 DOI: 10.1016/j.molbiopara.2020.111324] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 09/02/2020] [Accepted: 09/11/2020] [Indexed: 01/08/2023]
Abstract
The cellular membranes of Trypanosoma cruzi, like all eukaryotes, contain varying amounts of phospholipids, sphingolipids, neutral lipids and sterols. A multitude of pathways exist for the de novo synthesis of these lipid families but Trypanosoma cruzi has also become adapted to scavenge some of these lipids from the host. Completion of the TriTryp genomes has led to the identification of many putative genes involved in lipid synthesis, revealing some interesting differences to higher eukaryotes. Although many enzymes involved in lipid synthesis have yet to be characterised, completed experiments have shown the indispensability of some lipid metabolic pathways. Furthermore, the bioactive lipids of Trypanosoma cruzi and their effects on the host are becoming increasingly studied. Further studies on lipid metabolism in Trypanosoma cruzi will no doubt reveal some attractive targets for therapeutic intervention as well as reveal the interplay between parasite lipids, host response and pathogenesis.
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Affiliation(s)
- Leigh-Ann Booth
- Biomedical Sciences Research Complex, University of St Andrews, North Haugh, St Andrews, Scotland, KY16 9ST, United Kingdom
| | - Terry K Smith
- Biomedical Sciences Research Complex, University of St Andrews, North Haugh, St Andrews, Scotland, KY16 9ST, United Kingdom.
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8
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Dawoody Nejad L, Stumpe M, Rauch M, Hemphill A, Schneiter R, Bütikofer P, Serricchio M. Mitochondrial sphingosine-1-phosphate lyase is essential for phosphatidylethanolamine synthesis and survival of Trypanosoma brucei. Sci Rep 2020; 10:8268. [PMID: 32427974 PMCID: PMC7237492 DOI: 10.1038/s41598-020-65248-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 04/29/2020] [Indexed: 01/18/2023] Open
Abstract
Sphingosine-1-phosphate is a signaling molecule involved in the control of cell migration, differentiation, survival and other physiological processes. This sphingolipid metabolite can be degraded by the action of sphingosine-1-phosphate lyase (SPL) to form hexadecenal and ethanolamine phosphate. The importance of SPL-mediated ethanolamine phosphate formation has been characterized in only few cell types. We show that in the protozoan parasite Trypanosoma brucei, expression of TbSpl is essential for cell survival. Ablation of TbSpl expression increased sphingosine-1-phosphate levels and reduced de novo formation and steady-state levels of the glycerophospholipid phosphatidylethanolamine (PE). Growth of TbSpl-depleted parasites could be in part rescued by ethanolamine supplementation to the growth medium, indicating that the main function of TbSpl is to provide ethanolamine phosphate for PE synthesis. In contrast to most cell types analyzed, where SPL localizes to the endoplasmic reticulum, we found by high-resolution microscopy that TbSpl is a mitochondrial protein. In spite of its mitochondrial localization, TbSpl depletion had no apparent effect on mitochondrial morphology but resulted in aggregation of acidocalcisomes. Our results link mitochondria to sphingolipid metabolism and suggest possible roles for PE in acidocalcisome function.
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Affiliation(s)
- Ladan Dawoody Nejad
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bern, Switzerland.,Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Michael Stumpe
- Division of Biochemistry, Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Monika Rauch
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bern, Switzerland
| | - Andrew Hemphill
- Institute of Parasitology, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Roger Schneiter
- Division of Biochemistry, Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Peter Bütikofer
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bern, Switzerland.
| | - Mauro Serricchio
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bern, Switzerland.
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Moitra S, Pawlowic MC, Hsu FF, Zhang K. Phosphatidylcholine synthesis through cholinephosphate cytidylyltransferase is dispensable in Leishmania major. Sci Rep 2019; 9:7602. [PMID: 31110206 PMCID: PMC6527706 DOI: 10.1038/s41598-019-44086-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Accepted: 05/09/2019] [Indexed: 11/20/2022] Open
Abstract
Phosphatidylcholine (PC) is a major cell membrane constituent and precursor of important second messengers. In Leishmania parasites, PC synthesis can occur via the choline branch of the Kennedy pathway, the N-methylation of phosphatidylethanolamine (PE), or the remodeling of exogenous phospholipids. To investigate the role of de novo PC synthesis in Leishmania major, we focused on the cholinephosphate cytidylyltransferase (CPCT) which catalyzes the formation of CDP-choline, a key intermediate in the choline branch of the Kennedy pathway. Without CPCT, L. major parasites cannot incorporate choline into PC, yet the CPCT-null mutants contain similar levels of PC and PE as wild type parasites. Loss of CPCT does not affect the growth of parasites in complete medium or their virulence in mice. These results suggest that other mechanisms of PC synthesis can compensate the loss of CPCT. Importantly, CPCT-null parasites exhibited severe growth defects when ethanolamine and exogenous lipids became limited or when they were co-cultured with certain bacteria that are known to be members of sandfly midgut microbiota. These findings suggest that Leishmania employ multiple PC synthesis pathways to utilize a diverse pool of nutrients, which may be crucial for their survival and development in the sandfly.
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Affiliation(s)
- Samrat Moitra
- Department of Biological Sciences, Texas Tech University, Lubbock, TX, 79409, USA
| | - Mattie C Pawlowic
- Department of Biological Sciences, Texas Tech University, Lubbock, TX, 79409, USA
- Wellcome Centre for Anti-Infectives Research (WCAIR), Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
| | - Fong-Fu Hsu
- Department of Internal Medicine, Washington University School of Medicine, 660S. Euclid Ave., Saint Louis, MO, 63110, USA
| | - Kai Zhang
- Department of Biological Sciences, Texas Tech University, Lubbock, TX, 79409, USA.
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10
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Tams RN, Cassilly CD, Anaokar S, Brewer WT, Dinsmore JT, Chen YL, Patton-Vogt J, Reynolds TB. Overproduction of Phospholipids by the Kennedy Pathway Leads to Hypervirulence in Candida albicans. Front Microbiol 2019; 10:86. [PMID: 30792701 PMCID: PMC6374345 DOI: 10.3389/fmicb.2019.00086] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Accepted: 01/16/2019] [Indexed: 12/18/2022] Open
Abstract
Candida albicans is an opportunistic human fungal pathogen that causes life-threatening systemic infections, as well as oral mucosal infections. Phospholipids are crucial for pathogenesis in C. albicans, as disruption of phosphatidylserine (PS) and phosphatidylethanolamine (PE) biosynthesis within the cytidine diphosphate diacylglycerol (CDP-DAG) pathway causes avirulence in a mouse model of systemic infection. The synthesis of PE by this pathway plays a crucial role in virulence, but it was unknown if downstream conversion of PE to phosphatidylcholine (PC) is required for pathogenicity. Therefore, the enzymes responsible for methylating PE to PC, Pem1 and Pem2, were disrupted. The resulting pem1Δ/Δ pem2Δ/Δ mutant was not less virulent in mice, but rather hypervirulent. Since the pem1Δ/Δ pem2Δ/Δ mutant accumulated PE, this led to the hypothesis that increased PE synthesis increases virulence. To test this, the alternative Kennedy pathway for PE/PC synthesis was exploited. This pathway makes PE and PC from exogenous ethanolamine and choline, respectively, using three enzymatic steps. In contrast to Saccharomyces cerevisiae, C. albicans was found to use one enzyme, Ept1, for the final enzymatic step (ethanolamine/cholinephosphotransferase) that generates both PE and PC. EPT1 was overexpressed, which resulted in increases in both PE and PC synthesis. Moreover, the EPT1 overexpression strain is hypervirulent in mice and causes them to succumb to system infection more rapidly than wild-type. In contrast, disruption of EPT1 causes loss of PE and PC synthesis by the Kennedy pathway, and decreased kidney fungal burden during the mouse systemic infection model, indicating a mild loss of virulence. In addition, the ept1Δ/Δ mutant exhibits decreased cytotoxicity against oral epithelial cells in vitro, whereas the EPT1 overexpression strain exhibits increased cytotoxicity. Taken altogether, our data indicate that mutations that result in increased PE synthesis cause greater virulence and mutations that decrease PE synthesis attenuate virulence.
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Affiliation(s)
- Robert N Tams
- Department of Microbiology, The University of Tennessee, Knoxville, Knoxville, TN, United States
| | - Chelsi D Cassilly
- Department of Microbiology, The University of Tennessee, Knoxville, Knoxville, TN, United States
| | - Sanket Anaokar
- Department of Biological Sciences, Duquesne University, Pittsburgh, PA, United States
| | - William T Brewer
- Department of Microbiology, The University of Tennessee, Knoxville, Knoxville, TN, United States
| | - Justin T Dinsmore
- Department of Microbiology, The University of Tennessee, Knoxville, Knoxville, TN, United States
| | - Ying-Lien Chen
- Department of Plant Pathology and Microbiology, National Taiwan University, Taipei, Taiwan
| | - Jana Patton-Vogt
- Department of Biological Sciences, Duquesne University, Pittsburgh, PA, United States
| | - Todd B Reynolds
- Department of Microbiology, The University of Tennessee, Knoxville, Knoxville, TN, United States
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11
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Osorio-Méndez JF, Cevallos AM. Discovery and Genetic Validation of Chemotherapeutic Targets for Chagas' Disease. Front Cell Infect Microbiol 2019; 8:439. [PMID: 30666299 PMCID: PMC6330712 DOI: 10.3389/fcimb.2018.00439] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2018] [Accepted: 12/10/2018] [Indexed: 01/06/2023] Open
Abstract
There is an urgent need to develop new treatments for Chagas' disease. To identify drug targets, it is important to understand the basic biology of Trypanosoma cruzi, in particular with respect to the biological pathways or proteins that are essential for its survival within the host. This review provides a streamlined approach for identifying drug targets using freely available chemogenetic databases and outlines the relevant characteristics of an ideal chemotherapeutic target. Among those are their essentiality, druggability, availability of structural information, and selectivity. At the moment only 16 genes have been found as essential by gene disruption in T. cruzi. At the TDR Targets database, a chemogenomics resource for neglected diseases, information about published structures for these genes was only found for three of these genes, and annotation of validated inhibitors was found in two. These inhibitors have activity against the parasitic stages present in the host. We then analyzed three of the pathways that are considered promising in the search for new targets: (1) Ergosterol biosynthesis, (2) Resistance to oxidative stress, (3) Synthesis of surface glycoconjugates. We have annotated all the genes that participate in them, identified those that are considered as druggable, and incorporated evidence from either Trypanosoma brucei, and Leishmania spp. that supports the hypothesis that these pathways are essential for T. cruzi survival.
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Affiliation(s)
- Juan Felipe Osorio-Méndez
- Laboratorio de Microbiología y Biología Molecular, Programa de Medicina, Corporación Universitaria Empresarial Alexander von Humboldt, Armenia, Colombia.,Grupo de Estudio en Parasitología Molecular, Centro de Investigaciones Biomédicas, Universidad del Quindío, Armenia, Colombia
| | - Ana María Cevallos
- Departamento de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, Mexico
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12
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Kong P, Lehmann MJ, Helms JB, Brouwers JF, Gupta N. Lipid analysis of Eimeria sporozoites reveals exclusive phospholipids, a phylogenetic mosaic of endogenous synthesis, and a host-independent lifestyle. Cell Discov 2018; 4:24. [PMID: 29844921 PMCID: PMC5964319 DOI: 10.1038/s41421-018-0023-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Revised: 02/27/2018] [Accepted: 03/01/2018] [Indexed: 12/16/2022] Open
Abstract
Successful inter-host transmission of most apicomplexan parasites requires the formation of infective sporozoites within the oocysts. Unlike all other infective stages that are strictly intracellular and depend on host resources, the sporozoite stage develops outside the host cells, but little is known about its self-governing metabolism. This study deployed Eimeria falciformis, a parasite infecting the mouse as its natural host, to investigate the process of phospholipid biogenesis in sporozoites. Lipidomic analyses demonstrated the occurrence of prototypical phospholipids along with abundant expression of at least two exclusive lipids, phosphatidylthreonine (PtdThr) and inositol phosphorylceramide with a phytosphingosine backbone, in sporozoites. To produce them de novo, the parasite harbors nearly the entire biogenesis network, which is an evolutionary mosaic of eukaryotic-type and prokaryotic-type enzymes. Notably, many have no phylogenetic counterpart or functional equivalent in the mammalian host. Using Toxoplasma gondii as a gene-tractable surrogate to examine Eimeria enzymes, we show a highly compartmentalized network of lipid synthesis spread primarily in the apicoplast, endoplasmic reticulum, mitochondrion, and Golgi complex. Likewise, trans-genera complementation of a Toxoplasma mutant with the PtdThr synthase from Eimeria reveals a convergent role of PtdThr in fostering the lytic cycle of coccidian parasites. Taken together, our work establishes a model of autonomous membrane biogenesis involving significant inter-organelle cooperation and lipid trafficking in sporozoites. Phylogenetic divergence of certain pathways offers attractive drug targets to block the sporulation and subsequent transmission. Not least, our results vindicate the possession of an entire de novo lipid synthesis network in a representative protist adapted to an obligate intracellular parasitic lifestyle.
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Affiliation(s)
- Pengfei Kong
- Department of Molecular Parasitology, Faculty of Life Sciences, Humboldt University, Berlin, 10115 Germany
| | - Maik J. Lehmann
- Department of Molecular Parasitology, Faculty of Life Sciences, Humboldt University, Berlin, 10115 Germany
- Present Address: Department of Life Sciences and Engineering, University of Applied Sciences, Bingen, 55411 Germany
| | - J. Bernd Helms
- Department of Biochemistry and Cell Biology, Institute of Biomembranes, Utrecht University, Utrecht, 3584CM The Netherlands
| | - Jos F. Brouwers
- Department of Biochemistry and Cell Biology, Institute of Biomembranes, Utrecht University, Utrecht, 3584CM The Netherlands
| | - Nishith Gupta
- Department of Molecular Parasitology, Faculty of Life Sciences, Humboldt University, Berlin, 10115 Germany
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13
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Lee S, Cheung-See-Kit M, Williams TA, Yamout N, Zufferey R. The glycosomal alkyl-dihydroxyacetonephosphate synthase TbADS is essential for the synthesis of ether glycerophospholipids in procyclic trypanosomes. Exp Parasitol 2018; 185:71-78. [PMID: 29355496 DOI: 10.1016/j.exppara.2018.01.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Revised: 12/30/2017] [Accepted: 01/14/2018] [Indexed: 01/15/2023]
Abstract
Glycerophospholipids are the main constituents of the biological membranes in Trypanosoma brucei, which causes sleeping sickness in humans. The present work reports the characterization of the alkyl-dihydroxyacetonephosphate synthase TbADS that catalyzes the committed step in ether glycerophospholipid biosynthesis. TbADS localizes to the glycosomal lumen. TbADS complemented a null mutant of Leishmania major lacking alkyl-dihydroxyacetonephosphate synthase activity and restored the formation of normal form of the ether lipid based virulence factor lipophosphoglycan. Despite lacking alkyl-dihydroxyacetonephosphate synthase activity, a null mutant of TbADS in procyclic trypanosomes remained viable and exhibited normal growth. Comprehensive analysis of cellular glycerophospholipids showed that TbADS was involved in the biosynthesis of all ether glycerophospholipid species, primarily found in the PE and PC classes.
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Affiliation(s)
- Sungsu Lee
- Department of Biological Sciences, St John's University, 8000 Utopia Parkway, Jamaica, NY 11439, USA
| | - Melanie Cheung-See-Kit
- Department of Biological Sciences, St John's University, 8000 Utopia Parkway, Jamaica, NY 11439, USA
| | - Tyler A Williams
- Department of Biological Sciences, St John's University, 8000 Utopia Parkway, Jamaica, NY 11439, USA
| | - Nader Yamout
- Department of Biological Sciences, St John's University, 8000 Utopia Parkway, Jamaica, NY 11439, USA
| | - Rachel Zufferey
- Department of Biological Sciences, St John's University, 8000 Utopia Parkway, Jamaica, NY 11439, USA.
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14
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Comparative sphingolipidomics of disease-causing trypanosomatids reveal unique lifecycle- and taxonomy-specific lipid chemistries. Sci Rep 2017; 7:13617. [PMID: 29051559 PMCID: PMC5648825 DOI: 10.1038/s41598-017-13931-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Accepted: 10/03/2017] [Indexed: 12/16/2022] Open
Abstract
Trypanosomatids are parasitic protozoa which cause a spectrum of diseases, including trypanosomiasis and leishmaniasis, affecting millions of humans and animals worldwide. The surface of most protozoan parasites is heavily decorated with lipids and lipid-anchored molecules, forming protective barriers and acting as virulence factors during infection. Sphingolipids (SP) are major components of eukaryotic biomembranes, which play important roles in structural integrity, energy homeostasis and signaling. However, the precise chemical composition of SP in pathogens as well as their biochemical pathways and functions remain poorly characterized. Here, we present the first system-scale analyses of SP found in a panel of 7 trypanosomatids, including Leishmania donovani, Trypanosoma brucei and Trypanosoma cruzi. We characterized the structure of aminoethylphosphonate-containing ceramides, which are found exclusively in stercorarian Trypanosoma. Employing the sensitive and semi-quantitative sphingolipidomics approach that we developed, we report the detection of over 300 molecular species of SP, and identified unique metabolic signatures which serve as discriminants of the pathogens based on their taxonomy and lifecycle stages. The deep sphingolipidome presented here is an important biochemical and technological resource for future works to dissect SP metabolism and functions in these medically and agriculturally relevant systems.
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15
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Biagiotti M, Dominguez S, Yamout N, Zufferey R. Lipidomics and anti-trypanosomatid chemotherapy. Clin Transl Med 2017; 6:27. [PMID: 28766182 PMCID: PMC5539062 DOI: 10.1186/s40169-017-0160-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Accepted: 07/26/2017] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND Trypanosomatids such as Leishmania, Trypanosoma brucei and Trypanosoma cruzi belong to the order Kinetoplastida and are the source of many significant human and animal diseases. Current treatment is unsatisfactory and is compromised by the rising appearance of drug resistant parasites. Novel and more effective chemotherapeutics are urgently needed to treat and prevent these devastating diseases, which relies on the identification of essential, parasite specific targets that are absent in the host. Lipids constitute essential components of the cell and carry out multiple critical functions from building blocks of biological membranes to regulatory roles in signal transduction, organellar biogenesis, energy storage, and virulence. The recent technological advances of lipidomics has facilitated the broadening of our knowledge in the field of cellular lipid content, structure, functions, and metabolic pathways. MAIN BODY This review highlights the application of lipidomics (i) in the characterization of the lipidome of kinetoplastid parasites or of their subcellular structure(s), (ii) in the identification of unique lipid species or metabolic pathways that can be targeted for novel drug therapies, (iii) as an analytic tool to gain a deeper insight into the roles of specific enzymes in lipid metabolism using genetically modified microorganisms, and (iv) in deciphering the mechanism of action of anti-microbial drugs on lipid metabolism. Lastly, an outlook stating where the field is evolving is presented. CONCLUSION Lipidomics has contributed to the expanding knowledge related to lipid metabolism, mechanism of drug action and resistance, and pathogen-host interaction of trypanosomatids, which provides a solid basis for the development of better anti-parasitic pharmaceuticals.
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Affiliation(s)
| | | | - Nader Yamout
- St John's University, 8000 Utopia Parkway, Queens, NY, 11439, USA
| | - Rachel Zufferey
- St John's University, 8000 Utopia Parkway, Queens, NY, 11439, USA.
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16
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Pulido SA, Nguyen VH, Alzate JF, Cedeño DL, Makurath MA, Ríos-Vásquez A, Duque-Benítez SM, Jones MA, Robledo SM, Friesen JA. Insights into the phosphatidylcholine and phosphatidylethanolamine biosynthetic pathways in Leishmania parasites and characterization of a choline kinase from Leishmania infantum. Comp Biochem Physiol B Biochem Mol Biol 2017; 213:45-54. [PMID: 28754315 DOI: 10.1016/j.cbpb.2017.07.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Revised: 07/17/2017] [Accepted: 07/20/2017] [Indexed: 11/25/2022]
Abstract
The protozoan parasite Leishmania infantum is a causative agent of the disease visceral leishmaniasis, which can be fatal if not properly treated. Phosphatidylcholine (PC) and phosphatidylethanolamine (PE) biosynthesis pathways are attractive targets for new antileishmanial compounds since these Leishmania cell membrane phospholipids are important for parasite morphology and physiology. In this work we observed Leishmania synthesize PC and PE from extracellular choline and ethanolamine, respectively, suggesting the presence of CDP-choline and CDP-ethanolamine pathways. In addition, Leishmania converted PE to PC, indicating the parasite possesses phosphatidylethanolamine N-methyltransferase (PEMT) activity. The first step in the biosynthesis of PC or PE requires the phosphorylation of choline or ethanolamine by a kinase. We cloned the gene encoding a putative choline/ethanolamine kinase from Leishmania infantum and expressed and purified the encoded recombinant protein. The enzyme possesses choline kinase activity with a Vmax of 3.52μmol/min/mg and an apparent Km value of 0.089mM with respect to choline. The enzyme can also phosphorylate ethanolamine in vitro, but the apparent Km for ethanolamine is 850-fold greater than for choline. In an effort to probe requirements for small molecule inhibition of Leishmania choline kinase, the recombinant enzyme was evaluated for the ability to be inhibited by novel quaternary ammonium salts. The most effective inhibitor was N-iodomethyl-N,N,-dimethyl-N-(6,6-diphenyl hex-5-en-1-yle) ammonium iodide, denoted compound C6. In the presence of 4mM compound C6, the Vmax/Km decreased to approximately 1% of the wild-type catalytic efficiency. In addition, in Leishmania cells treated with compound C6 choline transport was inhibited.
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Affiliation(s)
- Sergio A Pulido
- Program for Study and Control of Tropical Diseases-PECET, School of Medicine, University of Antioquia, Medellin, Colombia
| | - Victoria H Nguyen
- Department of Chemistry, Illinois State University, Normal, IL 61790, USA
| | - Juan F Alzate
- Parasitology Group, School of Medicine, University of Antioquia, Medellin, Colombia
| | - David L Cedeño
- Department of Chemistry, Illinois State University, Normal, IL 61790, USA
| | - Monika A Makurath
- Department of Chemistry, Illinois State University, Normal, IL 61790, USA
| | | | | | - Marjorie A Jones
- Department of Chemistry, Illinois State University, Normal, IL 61790, USA
| | - Sara M Robledo
- Program for Study and Control of Tropical Diseases-PECET, School of Medicine, University of Antioquia, Medellin, Colombia
| | - Jon A Friesen
- Department of Chemistry, Illinois State University, Normal, IL 61790, USA.
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17
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Zufferey R, Pirani K, Cheung-See-Kit M, Lee S, Williams TA, Chen DG, Hossain MF. The Trypanosoma brucei dihydroxyacetonephosphate acyltransferase TbDAT is dispensable for normal growth but important for synthesis of ether glycerophospholipids. PLoS One 2017; 12:e0181432. [PMID: 28715456 PMCID: PMC5513551 DOI: 10.1371/journal.pone.0181432] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Accepted: 06/30/2017] [Indexed: 01/28/2023] Open
Abstract
Glycerophospholipids are the most abundant constituents of biological membranes in Trypanosoma brucei, which causes sleeping sickness in humans and nagana in cattle. They are essential cellular components that fulfill various important functions beyond their structural role in biological membranes such as in signal transduction, regulation of membrane trafficking or control of cell cycle progression. Our previous studies have established that the glycerol-3-phosphate acyltransferase TbGAT is dispensable for growth, viability, and ester lipid biosynthesis suggesting the existence of another initial acyltransferase(s). This work presents the characterization of the alternative, dihydroxyacetonephosphate acyltransferase TbDAT, which acylates primarily dihydroxyacetonephosphate and prefers palmitoyl-CoA as an acyl-CoA donor. TbDAT restores the viability of a yeast double null mutant that lacks glycerol-3-phosphate and dihydroxyacetonephosphate acyltransferase activities. A conditional null mutant of TbDAT in T. brucei procyclic form was created and characterized. TbDAT was important for survival during stationary phase and synthesis of ether lipids. In contrast, TbDAT was dispensable for normal growth. Our results show that in T. brucei procyclic forms i) TbDAT but not TbGAT is the physiologically relevant initial acyltransferase and ii) ether lipid precursors are primarily made by TbDAT.
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Affiliation(s)
- Rachel Zufferey
- Department of Biochemistry, Kansas State University, Manhattan, Kansas, United States of America.,Department of Biological Sciences, St. John's University, Queens, New York, United States of America
| | - Karim Pirani
- Department of Biochemistry, Kansas State University, Manhattan, Kansas, United States of America
| | - Melanie Cheung-See-Kit
- Department of Biological Sciences, St. John's University, Queens, New York, United States of America
| | - Sungsu Lee
- Department of Biological Sciences, St. John's University, Queens, New York, United States of America
| | - Tyler A Williams
- Department of Biological Sciences, St. John's University, Queens, New York, United States of America
| | - Daniel G Chen
- Department of Biological Sciences, St. John's University, Queens, New York, United States of America
| | - Md Faruk Hossain
- Department of Biological Sciences, St. John's University, Queens, New York, United States of America
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18
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Farine L, Jelk J, Choi J, Voelker DR, Nunes J, Smith TK, Bütikofer P. Phosphatidylserine synthase 2 and phosphatidylserine decarboxylase are essential for aminophospholipid synthesis in Trypanosoma brucei. Mol Microbiol 2017; 104:412-427. [PMID: 28142188 PMCID: PMC5413845 DOI: 10.1111/mmi.13637] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/26/2017] [Indexed: 01/09/2023]
Abstract
Phosphatidylethanolamine (PE) and phosphatidylserine (PS) are ubiquitously expressed and metabolically interconnected glycerophospholipids in eukaryotes and prokaryotes. In Trypanosoma brucei, PE synthesis has been shown to occur mainly via the Kennedy pathway, one of the three routes leading to PE synthesis in eukaryotes, while PS synthesis has not been studied experimentally. We now reveal the importance of T. brucei PS synthase 2 (TbPSS2) and T. brucei PS decarboxylase (TbPSD), two key enzymes involved in aminophospholipid synthesis, for trypanosome viability. By using tetracycline-inducible down-regulation of gene expression and in vivo and in vitro metabolic labeling, we found that TbPSS2 (i) is necessary for normal growth of procyclic trypanosomes, (ii) localizes to the endoplasmic reticulum and (iii) represents the unique route for PS formation in T. brucei. In addition, we identified TbPSD as type I PS decarboxylase in the mitochondrion and found that it is processed proteolytically at a WGSS cleavage site into a heterodimer. Down-regulation of TbPSD expression affected mitochondrial integrity in both procyclic and bloodstream form trypanosomes, decreased ATP production via oxidative phosphorylation in procyclic form and affected parasite growth.
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Affiliation(s)
- Luce Farine
- Institute of Biochemistry and Molecular MedicineUniversity of BernBern3012Switzerland
| | - Jennifer Jelk
- Institute of Biochemistry and Molecular MedicineUniversity of BernBern3012Switzerland
| | - Jae‐Yeon Choi
- Department of MedicineNational Jewish HealthDenverCO80206USA
| | | | - Jon Nunes
- Biomedical Sciences Research ComplexUniversity of St. AndrewsSt. AndrewsScotland
| | - Terry K. Smith
- Biomedical Sciences Research ComplexUniversity of St. AndrewsSt. AndrewsScotland
| | - Peter Bütikofer
- Institute of Biochemistry and Molecular MedicineUniversity of BernBern3012Switzerland
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19
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Pawlowic M, Hsu FF, Moitra S, Biyani N, Zhang K. Plasmenylethanolamine synthesis in Leishmania major. Mol Microbiol 2016; 101:238-49. [PMID: 27062077 PMCID: PMC4935589 DOI: 10.1111/mmi.13387] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/28/2016] [Indexed: 02/06/2023]
Abstract
Ethanolamine glycerophospholipids are ubiquitous cell membrane components. Trypanosomatid parasites of the genus Leishmania synthesize the majority of their ethanolamine glycerophospholipids as 1-O-alk-1'-enyl-2-acyl-sn-glycero-3-phosphoethanolamine or plasmenylethanolamine (PME) through the Kennedy pathway. PME is a subtype of ether phospholipids also known as ethanolamine plasmalogen whose functions are not well characterized. In this study, we investigated the role of PME synthesis in Leishmania major through the characterization of an ethanolamine phosphotransferase (EPT) mutant. EPT-null parasites are largely devoid of PME and fully viable in regular medium but fail to proliferate in the absence of fetal bovine serum. They exhibit significant abnormalities in the synthesis and localization of GPI-anchored surface molecules. EPT-null mutants also show attenuated virulence in BALB/c mice. Furthermore, in addition to PME synthesis, ethanolamine also contributes to the production of phosphatidylcholine, the most abundant class of lipids in Leishmania. Together, these findings suggest that ethanolamine production is likely required for Leishmania promastigotes to generate bulk phospholipids, to handle stress, and to control the expression of membrane bound virulence factors.
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Affiliation(s)
- Mattie Pawlowic
- Department of Biological Sciences, Texas Tech University, Lubbock, TX 79409, USA
| | - Fong-fu Hsu
- Department of Internal Medicine, Washington University School of Medicine, 660 S. Euclid Ave., Saint Louis, MO 63110, USA
| | - Samrat Moitra
- Department of Biological Sciences, Texas Tech University, Lubbock, TX 79409, USA
| | - Neha Biyani
- Department of Biological Sciences, Texas Tech University, Lubbock, TX 79409, USA
| | - Kai Zhang
- Department of Biological Sciences, Texas Tech University, Lubbock, TX 79409, USA
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20
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Patel N, Pirani KA, Zhu T, Cheung-See-Kit M, Lee S, Chen DG, Zufferey R. The Glycerol-3-Phosphate Acyltransferase TbGAT is Dispensable for Viability and the Synthesis of Glycerolipids in Trypanosoma brucei. J Eukaryot Microbiol 2016; 63:598-609. [PMID: 26909872 DOI: 10.1111/jeu.12309] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2015] [Revised: 01/30/2016] [Accepted: 02/16/2016] [Indexed: 01/09/2023]
Abstract
Glycerolipids are the main constituents of biological membranes in Trypanosoma brucei, which causes sleeping sickness in humans. Importantly, they occur as a structural component of the glycosylphosphatidylinositol lipid anchor of the abundant cell surface glycoproteins procyclin in procyclic forms and variant surface glycoprotein in bloodstream form, that play crucial roles for the development of the parasite in the insect vector and the mammalian host, respectively. The present work reports the characterization of the glycerol-3-phosphate acyltransferase TbGAT that initiates the biosynthesis of ester glycerolipids. TbGAT restored glycerol-3-phosphate acyltransferase activity when expressed in a Leishmania major deletion strain lacking this activity and exhibited preference for medium length, unsaturated fatty acyl-CoAs. TbGAT localized to the endoplasmic reticulum membrane with its N-terminal domain facing the cytosol. Despite that a TbGAT null mutant in T. brucei procyclic forms lacked glycerol-3-phosphate acyltransferase activity, it remained viable and exhibited similar growth rate as the wild type. TbGAT was dispensable for the biosynthesis of phosphatidylcholine, phosphatidylinositol, phosphatidylserine, and GPI-anchored protein procyclin. However, the null mutant exhibited a slight decrease in phosphatidylethanolamine biosynthesis that was compensated with a modest increase in production of ether phosphatidylcholine. Our data suggest that an alternative initial acyltransferase takes over TbGAT's function in its absence.
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Affiliation(s)
- Nipul Patel
- Department of Biological Sciences, St John's University, 8000 Utopia Parkway, Jamaica, New York, 11439
| | - Karim A Pirani
- Department of Biochemistry, Kansas State University, Manhattan, Kansas, 66506
| | - Tongtong Zhu
- Department of Biological Sciences, St John's University, 8000 Utopia Parkway, Jamaica, New York, 11439
| | - Melanie Cheung-See-Kit
- Department of Biological Sciences, St John's University, 8000 Utopia Parkway, Jamaica, New York, 11439
| | - Sungsu Lee
- Department of Biological Sciences, St John's University, 8000 Utopia Parkway, Jamaica, New York, 11439
| | - Daniel G Chen
- Department of Biological Sciences, St John's University, 8000 Utopia Parkway, Jamaica, New York, 11439
| | - Rachel Zufferey
- Department of Biological Sciences, St John's University, 8000 Utopia Parkway, Jamaica, New York, 11439.,Department of Biochemistry, Kansas State University, Manhattan, Kansas, 66506
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21
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Farine L, Niemann M, Schneider A, Bütikofer P. Phosphatidylethanolamine and phosphatidylcholine biosynthesis by the Kennedy pathway occurs at different sites in Trypanosoma brucei. Sci Rep 2015; 5:16787. [PMID: 26577437 PMCID: PMC4649479 DOI: 10.1038/srep16787] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2015] [Accepted: 10/20/2015] [Indexed: 02/04/2023] Open
Abstract
Phosphatidylethanolamine (PE) and phosphatidylcholine (PC) are among the most abundant phospholipids in biological membranes. In many eukaryotes, the CDP-ethanolamine and CDP-choline branches of the Kennedy pathway represent major and often essential routes for the production of PE and PC, with ethanolamine and choline/ethanolamine phosphotransferases (EPT and CEPT, respectively) catalysing the last reactions in the respective pathways. Although the site of PE and PC synthesis is commonly known to be the endoplasmic reticulum (ER), detailed information on the localization of the different phosphotransferases is lacking. In the unicellular parasite, Trypanosoma brucei, both branches of the Kennedy pathway are essential for cell growth in culture. We have previously reported that T. brucei EPT (TbEPT) catalyses the production of ether-type PE molecular species while T. brucei CEPT (TbCEPT) synthesizes diacyl-type PE and PC molecular species. We now show that the two enzymes localize to different sub-compartments of the ER. By expressing a series of tagged forms of the two enzymes in T. brucei parasites, in combination with sub-cellular fractionation and enzyme activity measurements, TbEPT was found exclusively in the perinuclear ER, a distinct area located close to but distinct from the nuclear membrane. In contrast, TbCEPT was detected in the bulk ER.
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Affiliation(s)
- Luce Farine
- Institute of Biochemistry and Molecular Medicine, University of Bern, 3012 Bern, Switzerland.,Graduate School for Cellular and Biomedical Sciences, University of Bern, 3012 Bern, Switzerland
| | - Moritz Niemann
- Department of Chemistry and Biochemistry, University of Bern, 3012 Bern, Switzerland
| | - André Schneider
- Department of Chemistry and Biochemistry, University of Bern, 3012 Bern, Switzerland
| | - Peter Bütikofer
- Institute of Biochemistry and Molecular Medicine, University of Bern, 3012 Bern, Switzerland
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22
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Lilley AC, Major L, Young S, Stark MJR, Smith TK. The essential roles of cytidine diphosphate-diacylglycerol synthase in bloodstream form Trypanosoma brucei. Mol Microbiol 2014; 92:453-70. [PMID: 24533860 PMCID: PMC4114554 DOI: 10.1111/mmi.12553] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/12/2014] [Indexed: 12/23/2022]
Abstract
Lipid metabolism in Trypanosoma brucei, the causative agent of African sleeping sickness, differs from its human host in several fundamental ways. This has lead to the validation of a plethora of novel drug targets, giving hope of novel chemical intervention against this neglected disease. Cytidine diphosphate diacylglycerol (CDP‐DAG) is a central lipid intermediate for several pathways in both prokaryotes and eukaryotes, being produced by CDP‐DAG synthase (CDS). However, nothing is known about the single T. brucei CDS gene (Tb927.7.220/EC 2.7.7.41) or its activity. In this study we show TbCDS is functional by complementation of a non‐viable yeast CDS null strain and that it is essential in the bloodstream form of the parasite via a conditional knockout. The TbCDS conditional knockout showed morphological changes including a cell‐cycle arrest due in part to kinetoplast segregation defects. Biochemical phenotyping of TbCDS conditional knockout showed drastically altered lipid metabolism where reducing levels of phosphatidylinositol detrimentally impacted on glycoylphosphatidylinositol biosynthesis. These studies also suggest that phosphatidylglycerol synthesized via the phosphatidylglycerol‐phosphate synthase is not synthesized from CDP‐DAG, as was previously thought. TbCDS was shown to localized the ER and Golgi, probably to provide CDP‐DAG for the phosphatidylinositol synthases.
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Affiliation(s)
- Alison C Lilley
- Biomedical Sciences Research Centre, School of Biology, The University of St. Andrews, The North Haugh, St. Andrews, Fife Scotland, KY16 9ST, UK
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23
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Hsu FF, Kuhlmann FM, Turk J, Beverley SM. Multiple-stage linear ion-trap with high resolution mass spectrometry towards complete structural characterization of phosphatidylethanolamines containing cyclopropane fatty acyl chain in Leishmania infantum. JOURNAL OF MASS SPECTROMETRY : JMS 2014; 49:201-9. [PMID: 24619546 PMCID: PMC4007172 DOI: 10.1002/jms.3327] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2013] [Revised: 12/06/2013] [Accepted: 12/11/2013] [Indexed: 05/24/2023]
Abstract
The structures of phosphatidylethanolamine (PE) in Leishmania infantum are unique in that they consist of a rare cyclopropane fatty acid (CFA) containing PE subfamily, including CFA-containing plasmalogen PE species. In this contribution, we applied multiple-stage linear ion-trap combined with high-resolution mass spectrometry to define the structures of PEs that were desorbed as [M - H](-) and [M - H + 2Li](+) ions by ESI, respectively. The structural information arising from MS(n) on both the molecular species are complimentary, permitting complete determination of PE structures, including the identities of the fatty acid substituents and their location on the glycerol backbone, more importantly, the positions of the double bond(s) and of the cyclopropane chain of the fatty acid chain, directing to the realization of the CFA biosynthesis pathways that were reported previously. We also uncovered the presence of a minor dimethyl-PE subclass that has not been previously reported in L. infantum. This LIT MS(n) mass spectrometric approach led to unambiguous identification of PE molecules including many isomers in complex mixture that would otherwise be very difficult to define using other analytical approaches.
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Affiliation(s)
- Fong-Fu Hsu
- Mass Spectrometry Resource, Division of Endocrinology, Diabetes, Metabolism and Lipid Research, USA
| | - F. Matthew Kuhlmann
- Division of Infectious Diseases, Washington University School of Medicine, St. Louis, MO, 63110, USA
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - John Turk
- Mass Spectrometry Resource, Division of Endocrinology, Diabetes, Metabolism and Lipid Research, USA
| | - Stephen M. Beverley
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, 63110, USA
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Hartmann A, Hellmund M, Lucius R, Voelker DR, Gupta N. Phosphatidylethanolamine synthesis in the parasite mitochondrion is required for efficient growth but dispensable for survival of Toxoplasma gondii. J Biol Chem 2014; 289:6809-6824. [PMID: 24429285 DOI: 10.1074/jbc.m113.509406] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Toxoplasma gondii is a highly prevalent obligate intracellular parasite of the phylum Apicomplexa, which also includes other parasites of clinical and/or veterinary importance, such as Plasmodium, Cryptosporidium, and Eimeria. Acute infection by Toxoplasma is hallmarked by rapid proliferation in its host cells and requires a significant synthesis of parasite membranes. Phosphatidylethanolamine (PtdEtn) is the second major phospholipid class in T. gondii. Here, we reveal that PtdEtn is produced in the parasite mitochondrion and parasitophorous vacuole by decarboxylation of phosphatidylserine (PtdSer) and in the endoplasmic reticulum by fusion of CDP-ethanolamine and diacylglycerol. PtdEtn in the mitochondrion is synthesized by a phosphatidylserine decarboxylase (TgPSD1mt) of the type I class. TgPSD1mt harbors a targeting peptide at its N terminus that is required for the mitochondrial localization but not for the catalytic activity. Ablation of TgPSD1mt expression caused up to 45% growth impairment in the parasite mutant. The PtdEtn content of the mutant was unaffected, however, suggesting the presence of compensatory mechanisms. Indeed, metabolic labeling revealed an increased usage of ethanolamine for PtdEtn synthesis by the mutant. Likewise, depletion of nutrients exacerbated the growth defect (∼56%), which was partially restored by ethanolamine. Besides, the survival and residual growth of the TgPSD1mt mutant in the nutrient-depleted medium also indicated additional routes of PtdEtn biogenesis, such as acquisition of host-derived lipid. Collectively, the work demonstrates a metabolic cooperativity between the parasite organelles, which ensures a sustained lipid synthesis, survival and growth of T. gondii in varying nutritional milieus.
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Affiliation(s)
- Anne Hartmann
- Department of Molecular Parasitology, Humboldt University, Philippstrasse 13, 10115 Berlin, Germany
| | - Maria Hellmund
- Department of Molecular Parasitology, Humboldt University, Philippstrasse 13, 10115 Berlin, Germany
| | - Richard Lucius
- Department of Molecular Parasitology, Humboldt University, Philippstrasse 13, 10115 Berlin, Germany
| | - Dennis R Voelker
- Department of Medicine, National Jewish Health, Denver, Colorado 80206
| | - Nishith Gupta
- Department of Molecular Parasitology, Humboldt University, Philippstrasse 13, 10115 Berlin, Germany; Department of Parasitology, Max-Planck Institute for Infection Biology, Charitéplatz 1, 10117 Berlin, Germany.
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25
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Gohil VM, Zhu L, Baker CD, Cracan V, Yaseen A, Jain M, Clish CB, Brookes PS, Bakovic M, Mootha VK. Meclizine inhibits mitochondrial respiration through direct targeting of cytosolic phosphoethanolamine metabolism. J Biol Chem 2013; 288:35387-95. [PMID: 24142790 PMCID: PMC3853286 DOI: 10.1074/jbc.m113.489237] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We recently identified meclizine, an over-the-counter drug, as an inhibitor of mitochondrial respiration. Curiously, meclizine blunted respiration in intact cells but not in isolated mitochondria, suggesting an unorthodox mechanism. Using a metabolic profiling approach, we now show that treatment with meclizine leads to a sharp elevation of cellular phosphoethanolamine, an intermediate in the ethanolamine branch of the Kennedy pathway of phosphatidylethanolamine biosynthesis. Metabolic labeling and in vitro enzyme assays confirmed direct inhibition of the cytosolic enzyme CTP:phosphoethanolamine cytidylyltransferase (PCYT2). Inhibition of PCYT2 by meclizine led to rapid accumulation of its substrate, phosphoethanolamine, which is itself an inhibitor of mitochondrial respiration. Our work identifies the first pharmacologic inhibitor of the Kennedy pathway, demonstrates that its biosynthetic intermediate is an endogenous inhibitor of respiration, and provides key mechanistic insights that may facilitate repurposing meclizine for disorders of energy metabolism.
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Affiliation(s)
- Vishal M Gohil
- From the Departments of Molecular Biology and Medicine, Center for Human Genetic Research, Massachusetts General Hospital, Boston, Massachusetts 02114
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Lipid synthesis in protozoan parasites: a comparison between kinetoplastids and apicomplexans. Prog Lipid Res 2013; 52:488-512. [PMID: 23827884 DOI: 10.1016/j.plipres.2013.06.003] [Citation(s) in RCA: 103] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2013] [Revised: 06/16/2013] [Accepted: 06/17/2013] [Indexed: 12/22/2022]
Abstract
Lipid metabolism is of crucial importance for pathogens. Lipids serve as cellular building blocks, signalling molecules, energy stores, posttranslational modifiers, and pathogenesis factors. Parasites rely on a complex system of uptake and synthesis mechanisms to satisfy their lipid needs. The parameters of this system change dramatically as the parasite transits through the various stages of its life cycle. Here we discuss the tremendous recent advances that have been made in the understanding of the synthesis and uptake pathways for fatty acids and phospholipids in apicomplexan and kinetoplastid parasites, including Plasmodium, Toxoplasma, Cryptosporidium, Trypanosoma and Leishmania. Lipid synthesis differs in significant ways between parasites from both phyla and the human host. Parasites have acquired novel pathways through endosymbiosis, as in the case of the apicoplast, have dramatically reshaped substrate and product profiles, and have evolved specialized lipids to interact with or manipulate the host. These differences potentially provide opportunities for drug development. We outline the lipid pathways for key species in detail as they progress through the developmental cycle and highlight those that are of particular importance to the biology of the pathogens and/or are the most promising targets for parasite-specific treatment.
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27
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Flis VV, Daum G. Lipid transport between the endoplasmic reticulum and mitochondria. Cold Spring Harb Perspect Biol 2013; 5:5/6/a013235. [PMID: 23732475 DOI: 10.1101/cshperspect.a013235] [Citation(s) in RCA: 137] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Mitochondria are partially autonomous organelles that depend on the import of certain proteins and lipids to maintain cell survival and membrane formation. Although phosphatidylglycerol, cardiolipin, and phosphatidylethanolamine are synthesized by mitochondrial enzymes, phosphatidylcholine, phosphatidylinositol, phosphatidylserine, and sterols need to be imported from other organelles. The origin of most lipids imported into mitochondria is the endoplasmic reticulum, which requires interaction of these two subcellular compartments. Recently, protein complexes that are involved in membrane contact between endoplasmic reticulum and mitochondria were identified, but their role in lipid transport is still unclear. In the present review, we describe components involved in lipid translocation between the endoplasmic reticulum and mitochondria and discuss functional as well as regulatory aspects that are important for lipid homeostasis.
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Affiliation(s)
- Vid V Flis
- Institute of Biochemistry, Graz University of Technology, A-8010 Graz, Austria
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28
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Identification of a novel lipin homologue from the parasitic protozoan Trypanosoma brucei. BMC Microbiol 2013; 13:101. [PMID: 23656927 PMCID: PMC3654991 DOI: 10.1186/1471-2180-13-101] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Accepted: 05/06/2013] [Indexed: 02/03/2023] Open
Abstract
Background Arginine methylation is a post-translational modification that expands the functional diversity of proteins. Kinetoplastid parasites contain a relatively large group of protein arginine methyltransferases (PRMTs) compared to other single celled eukaryotes. Several T. brucei proteins have been shown to serve as TbPRMT substrates in vitro, and a great number of proteins likely to undergo methylation are predicted by the T. brucei genome. This indicates that a large number of proteins whose functions are modulated by arginine methylation await discovery in trypanosomes. Here, we employed a yeast two-hybrid screen using as bait the major T. brucei type I PRMT, TbPRMT1, to identify potential substrates of this enzyme. Results We identified a protein containing N-LIP and C-LIP domains that we term TbLpn. These domains are usually present in a family of proteins known as lipins, and involved in phospholipid biosynthesis and gene regulation. Far western and co-immunoprecipitation assays confirmed the TbPRMT1-TbLpn interaction. We also demonstrated that TbLpn is localized mainly to the cytosol, and is methylated in vivo. In addition, we showed that, similar to mammalian and yeast proteins with N-LIP and C-LIP domains, recombinant TbLpn exhibits phosphatidic acid phosphatase activity, and that two conserved aspartic acid residues present in the C-LIP domain are critical for its enzymatic activity. Conclusions This study reports the characterization of a novel trypanosome protein and provides insight into its enzymatic activity and function in phospholipid biosynthesis. It also indicates that TbLpn functions may be modulated by arginine methylation.
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Regulation of Phosphatidylethanolamine Homeostasis—The Critical Role of CTP:Phosphoethanolamine Cytidylyltransferase (Pcyt2). Int J Mol Sci 2013; 14:2529-50. [PMID: 23354482 PMCID: PMC3588000 DOI: 10.3390/ijms14022529] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Revised: 01/02/2013] [Accepted: 01/17/2013] [Indexed: 12/21/2022] Open
Abstract
Phosphatidylethanolamine (PE) is the most abundant lipid on the protoplasmatic leaflet of cellular membranes. It has a pivotal role in cellular processes such as membrane fusion, cell cycle regulation, autophagy, and apoptosis. CTP:phosphoethanolamine cytidylyltransferase (Pcyt2) is the main regulatory enzyme in de novo biosynthesis of PE from ethanolamine and diacylglycerol by the CDP-ethanolamine Kennedy pathway. The following is a summary of the current state of knowledge on Pcyt2 and how splicing and isoform specific differences could lead to variations in functional properties in this family of enzymes. Results from the most recent studies on Pcyt2 transcriptional regulation, promoter function, autophagy, and cell growth regulation are highlighted. Recent data obtained from Pcyt2 knockout mouse models is also presented, demonstrating the essentiality of this gene in embryonic development as well as the major physiological consequences of deletion of one Pcyt2 allele. Those include development of symptoms of the metabolic syndrome such as elevated lipogenesis and lipoprotein secretion, hypertriglyceridemia, liver steatosis, obesity, and insulin resistance. The objective of this review is to elucidate the nature of Pcyt2 regulation by linking its catalytic function with the regulation of lipid and energy homeostasis.
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Biochemical characterization of Plasmodium falciparum CTP:phosphoethanolamine cytidylyltransferase shows that only one of the two cytidylyltransferase domains is active. Biochem J 2013. [DOI: 10.1042/bj20121480] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The intra-erythrocytic proliferation of the human malaria parasite Plasmodium falciparum requires massive synthesis of PE (phosphatidylethanolamine) that together with phosphatidylcholine constitute the bulk of the malaria membrane lipids. PE is mainly synthesized de novo by the CDP:ethanolamine-dependent Kennedy pathway. We previously showed that inhibition of PE biosynthesis led to parasite death. In the present study we characterized PfECT [P. falciparum CTP:phosphoethanolamine CT (cytidylyltransferase)], which we identified as the rate-limiting step of the PE metabolic pathway in the parasite. The cellular localization and expression of PfECT along the parasite life cycle were studied using polyclonal antibodies. Biochemical analyses showed that the enzyme activity follows Michaelis–Menten kinetics. PfECT is composed of two CT domains separated by a linker region. Activity assays on recombinant enzymes upon site-directed mutagenesis revealed that the N-terminal CT domain was the only catalytically active domain of PfECT. Concordantly, three-dimensional homology modelling of PfECT showed critical amino acid differences between the substrate-binding sites of the two CT domains. PfECT was predicted to fold as an intramolecular dimer suggesting that the inactive C-terminal domain is important for dimer stabilization. Given the absence of PE synthesis in red blood cells, PfECT represents a potential antimalarial target opening the way for a rational conception of bioactive compounds.
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31
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Povelones ML, Tiengwe C, Gluenz E, Gull K, Englund PT, Jensen RE. Mitochondrial shape and function in trypanosomes requires the outer membrane protein, TbLOK1. Mol Microbiol 2013; 87:713-29. [PMID: 23336702 DOI: 10.1111/mmi.12089] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/03/2012] [Indexed: 01/01/2023]
Abstract
In an RNAi library screen for loss of kinetoplast DNA (kDNA), we identified an uncharacterized Trypanosoma brucei protein, named TbLOK1, required for maintenance of mitochondrial shape and function. We found the TbLOK1 protein located in discrete patches in the mitochondrial outer membrane. Knock-down of TbLOK1 in procyclic trypanosomes caused the highly interconnected mitochondrial structure to collapse, forming an unbranched tubule remarkably similar to the streamlined organelle seen in the bloodstream form. Following RNAi, defects in mitochondrial respiration, inner membrane potential and mitochondrial transcription were observed. At later times following TbLOK1 depletion, kDNA was lost and a more drastic alteration in mitochondrial structure was found. Our results demonstrate the close relationship between organelle structure and function in trypanosomes.
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Affiliation(s)
- Megan L Povelones
- Department of Biological Chemistry, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
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32
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Farine L, Bütikofer P. The ins and outs of phosphatidylethanolamine synthesis in Trypanosoma brucei. Biochim Biophys Acta Mol Cell Biol Lipids 2012; 1831:533-42. [PMID: 23010476 DOI: 10.1016/j.bbalip.2012.09.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2012] [Revised: 09/07/2012] [Accepted: 09/16/2012] [Indexed: 12/23/2022]
Abstract
Phospholipids are not only major building blocks of biological membranes but fulfill a wide range of critical functions that are often widely unrecognized. In this review, we focus on phosphatidylethanolamine, a major glycerophospholipid class in eukaryotes and bacteria, which is involved in many unexpected biological processes. We describe (i) the ins, i.e. the substrate sources and biochemical reactions involved in phosphatidylethanolamine synthesis, and (ii) the outs, i.e. the different roles of phosphatidylethanolamine and its involvement in various cellular events. We discuss how the protozoan parasite, Trypanosoma brucei, has contributed and may contribute in the future as eukaryotic model organism to our understanding of phosphatidylethanolamine homeostasis. This article is part of a Special Issue entitled Phospholipids and Phospholipid Metabolism.
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Affiliation(s)
- Luce Farine
- Institute of Biochemistry and Molecular Medicine, University of Bern, 3012 Bern, Switzerland.
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Weingärtner A, Kemmer G, Müller FD, Zampieri RA, Gonzaga dos Santos M, Schiller J, Pomorski TG. Leishmania promastigotes lack phosphatidylserine but bind annexin V upon permeabilization or miltefosine treatment. PLoS One 2012; 7:e42070. [PMID: 22870283 PMCID: PMC3411662 DOI: 10.1371/journal.pone.0042070] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2012] [Accepted: 07/02/2012] [Indexed: 11/18/2022] Open
Abstract
The protozoan parasite Leishmania is an intracellular pathogen infecting and replicating inside vertebrate host macrophages. A recent model suggests that promastigote and amastigote forms of the parasite mimic mammalian apoptotic cells by exposing phosphatidylserine (PS) at the cell surface to trigger their phagocytic uptake into host macrophages. PS presentation at the cell surface is typically analyzed using fluorescence-labeled annexin V. Here we show that Leishmania promastigotes can be stained by fluorescence-labeled annexin V upon permeabilization or miltefosine treatment. However, combined lipid analysis by thin-layer chromatography, mass spectrometry and 31P nuclear magnetic resonance (NMR) spectroscopy revealed that Leishmania promastigotes lack any detectable amount of PS. Instead, we identified several other phospholipid classes such phosphatidic acid, phosphatidylethanolamine; phosphatidylglycerol and phosphatidylinositol as candidate lipids enabling annexin V staining.
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Affiliation(s)
- Adrien Weingärtner
- Institute of Biology, Humboldt-Universität zu Berlin, Berlin, Germany
- Helmholtz Center for Infektion Research, Braunschweig, Germany
| | - Gerdi Kemmer
- Department of Plant Biology and Biotechnology, University of Copenhagen, Frederiksberg C, Copenhagen, Denmark
| | | | - Ricardo Andrade Zampieri
- Instituto de Biociências, Departamento de Fisiologia, Universidade de São Paulo, São Paulo, Brazil
| | | | - Jürgen Schiller
- Institute of Medical Physics and Biophysics, University of Leipzig, Leipzig, Germany
| | - Thomas Günther Pomorski
- Department of Plant Biology and Biotechnology, University of Copenhagen, Frederiksberg C, Copenhagen, Denmark
- * E-mail:
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de Freitas-Junior PRG, Catta-Preta CMC, Andrade IDS, Cavalcanti DP, de Souza W, Einicker-Lamas M, Motta MCM. Effects of miltefosine on the proliferation, ultrastructure, and phospholipid composition of Angomonas deanei, a trypanosomatid protozoan that harbors a symbiotic bacterium. FEMS Microbiol Lett 2012; 333:129-37. [PMID: 22651853 DOI: 10.1111/j.1574-6968.2012.02607.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2012] [Revised: 05/22/2012] [Accepted: 05/22/2012] [Indexed: 11/28/2022] Open
Abstract
Some trypanosomatids, such as Angomonas deanei formerly named as Crithidia deanei, present an obligatory intracellular bacterium, which maintains a mutualistic relationship with the host. Phosphatidylcholine (PC) is the major phospholipid in eukaryotes and an essential component of cell membranes playing structural, biochemical, and physiological roles. However, in prokaryotes, PC is present only in those species closely associated with eukaryotes, either in symbiotic or pathogenic interactions. In trypanosomatids, the endosymbiont envelope is composed by a reduced cell wall and by two membrane units that lack sterols and present cardiolipin (CL) and PC as the major phospholipids. In this study, we tested the effects of miltefosine in A. deanei proliferation, as well as, on the ultrastrucuture and phospholipid composition considering that this drug inhibits the CTP-phosphocholine cytidyltransferase (CCT), a key enzyme in the PC biosynthesis. Besides the low effect of miltefosine in cellular proliferation, treated protozoa presented ultrastructural alterations such as plasma membrane shedding and blebbing, mitochondrial swelling, and convolutions of the endosymbiont envelope. The use of (32) Pi as a tracer revealed that the production of PC, CL, and phosphatidylethanolamine decreased while phosphatidylinositol production remained stable. Mitochondrion and symbiont fractions obtained from protozoa treated with miltefosine also presented a decrease in phospholipid production, reinforcing the idea that an intensive metabolic exchange occurs between the host trypanosomatid and structures of symbiotic origin.
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Affiliation(s)
- Paulo R G de Freitas-Junior
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
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35
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Abstract
Microorganisms depend on their ability to modulate their metabolic composition according to specific circumstances, such as different phases of the growth cycle and circadian rhythms, fluctuations in environmental conditions, as well as experimental perturbations. A thorough understanding of these metabolic adaptations requires the ability to comprehensively identify and quantify the metabolome of bacterial cells in different states. In this review, we present an overview of the diverse metabolomics approaches recently adopted to explore the metabolism of a wide variety of microorganisms. Focusing on a selection of illustrative case studies, we assess the different experimental designs used and explore the major achievements and remaining challenges in the field. We conclude by discussing the important complementary information provided by computational methods such as genome-scale metabolic modeling, which enable an integrated analysis of metabolic state changes in the context of overall cellular physiology.
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Gonzalez-Salgado A, Steinmann ME, Greganova E, Rauch M, Mäser P, Sigel E, Bütikofer P. myo-Inositol uptake is essential for bulk inositol phospholipid but not glycosylphosphatidylinositol synthesis in Trypanosoma brucei. J Biol Chem 2012; 287:13313-23. [PMID: 22351763 DOI: 10.1074/jbc.m112.344812] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
myo-Inositol is an essential precursor for the production of inositol phosphates and inositol phospholipids in all eukaryotes. Intracellular myo-inositol is generated by de novo synthesis from glucose 6-phosphate or is provided from the environment via myo-inositol symporters. We show that in Trypanosoma brucei, the causative pathogen of human African sleeping sickness and nagana in domestic animals, myo-inositol is taken up via a specific proton-coupled electrogenic symport and that this transport is essential for parasite survival in culture. Down-regulation of the myo-inositol transporter using RNA interference inhibited uptake of myo-inositol and blocked the synthesis of the myo-inositol-containing phospholipids, phosphatidylinositol and inositol phosphorylceramide; in contrast, it had no effect on glycosylphosphatidylinositol production. This together with the unexpected localization of the myo-inositol transporter in both the plasma membrane and the Golgi demonstrate that metabolism of endogenous and exogenous myo-inositol in T. brucei is strictly segregated.
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Affiliation(s)
- Amaia Gonzalez-Salgado
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bühlstrasse 28, 3012 Bern, Switzerland
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Creek DJ, Anderson J, McConville MJ, Barrett MP. Metabolomic analysis of trypanosomatid protozoa. Mol Biochem Parasitol 2011; 181:73-84. [PMID: 22027026 DOI: 10.1016/j.molbiopara.2011.10.003] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2011] [Revised: 10/04/2011] [Accepted: 10/06/2011] [Indexed: 01/05/2023]
Abstract
Metabolomics aims to measure all low molecular weight chemicals within a given system in a manner analogous to transcriptomics, proteomics and genomics. In this review we highlight metabolomics approaches that are currently being applied to the kinetoplastid parasites, Trypanosoma brucei and Leishmania spp. The use of untargeted metabolomics approaches, made possible through advances in mass spectrometry and informatics, and stable isotope labelling has increased our understanding of the metabolism in these organisms beyond the views established using classical biochemical approaches. Set within the context of metabolic networks, predicted using genome-wide reconstructions of metabolism, new hypotheses on how to target aspects of metabolism to design new drugs against these protozoa are emerging.
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Affiliation(s)
- Darren J Creek
- Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8TA, United Kingdom
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38
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Serricchio M, Bütikofer P. Trypanosoma brucei: a model micro-organism to study eukaryotic phospholipid biosynthesis. FEBS J 2011; 278:1035-46. [DOI: 10.1111/j.1742-4658.2011.08012.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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39
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Ginger ML, Fritz-Laylin LK, Fulton C, Cande WZ, Dawson SC. Intermediary metabolism in protists: a sequence-based view of facultative anaerobic metabolism in evolutionarily diverse eukaryotes. Protist 2010; 161:642-71. [PMID: 21036663 PMCID: PMC3021972 DOI: 10.1016/j.protis.2010.09.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Protists account for the bulk of eukaryotic diversity. Through studies of gene and especially genome sequences the molecular basis for this diversity can be determined. Evident from genome sequencing are examples of versatile metabolism that go far beyond the canonical pathways described for eukaryotes in textbooks. In the last 2-3 years, genome sequencing and transcript profiling has unveiled several examples of heterotrophic and phototrophic protists that are unexpectedly well-equipped for ATP production using a facultative anaerobic metabolism, including some protists that can (Chlamydomonas reinhardtii) or are predicted (Naegleria gruberi, Acanthamoeba castellanii, Amoebidium parasiticum) to produce H(2) in their metabolism. It is possible that some enzymes of anaerobic metabolism were acquired and distributed among eukaryotes by lateral transfer, but it is also likely that the common ancestor of eukaryotes already had far more metabolic versatility than was widely thought a few years ago. The discussion of core energy metabolism in unicellular eukaryotes is the subject of this review. Since genomic sequencing has so far only touched the surface of protist diversity, it is anticipated that sequences of additional protists may reveal an even wider range of metabolic capabilities, while simultaneously enriching our understanding of the early evolution of eukaryotes.
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Affiliation(s)
- Michael L Ginger
- School of Health and Medicine, Division of Biomedical and Life Sciences, Lancaster University, Lancaster LA1 4YQ, UK.
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40
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Ibrahim HMS, Al-Salabi MI, El Sabbagh N, Quashie NB, Alkhaldi AAM, Escale R, Smith TK, Vial HJ, de Koning HP. Symmetrical choline-derived dications display strong anti-kinetoplastid activity. J Antimicrob Chemother 2010; 66:111-25. [PMID: 21078603 DOI: 10.1093/jac/dkq401] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
OBJECTIVES to investigate the anti-kinetoplastid activity of choline-derived analogues with previously reported antimalarial efficacy. METHODS from an existing choline analogue library, seven antimalarial compounds, representative of the first-, second- and third-generation analogues previously developed, were assessed for activity against Trypanosoma and Leishmania spp. Using a variety of techniques, the effects of choline analogue exposure on the parasites were documented and a preliminary investigation of their mode of action was performed. RESULTS the activities of choline-derived compounds against Trypanosoma brucei and Leishmania mexicana were determined. The compounds displayed promising anti-kinetoplastid activity, particularly against T. brucei, to which 4/7 displayed submicromolar EC(50) values for the wild-type strain. Low micromolar concentrations of most compounds cleared trypanosome cultures within 24-48 h. The compounds inhibit a choline transporter in Leishmania, but their entry may not depend only on this carrier; T. b. brucei lacks a choline carrier and the mode of uptake remains unclear. The compounds had no effect on the overall lipid composition of the cells, cell cycle progression or cyclic adenosine monophosphate production or short-term effects on intracellular calcium levels. However, several of the compounds, displayed pronounced effects on the mitochondrial membrane potential; this action was not associated with production of reactive oxygen species but rather with a slow rise of intracellular calcium levels and DNA fragmentation. CONCLUSIONS the choline analogues displayed strong activity against kinetoplastid parasites, particularly against T. b. brucei. In contrast to their antimalarial activity, they did not act on trypanosomes by disrupting choline salvage or phospholipid metabolism, instead disrupting mitochondrial function, leading to chromosomal fragmentation.
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Affiliation(s)
- Hasan M S Ibrahim
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8TA, UK
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Gibellini F, Smith TK. The Kennedy pathway--De novo synthesis of phosphatidylethanolamine and phosphatidylcholine. IUBMB Life 2010; 62:414-28. [PMID: 20503434 DOI: 10.1002/iub.337] [Citation(s) in RCA: 312] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The glycerophospholipids phosphatidylcholine (PC) and phosphatidylethanolamine (PE) account for greater than 50% of the total phospholipid species in eukaryotic membranes and thus play major roles in the structure and function of those membranes. In most eukaryotic cells, PC and PE are synthesized by an aminoalcoholphosphotransferase reaction, which uses sn-1,2-diradylglycerol and either CDP-choline or CDP-ethanolamine, respectively. This is the last step in a biosynthetic pathway known as the Kennedy pathway, so named after Eugene Kennedy who elucidated it over 50 years ago. This review will cover various aspects of the Kennedy pathway including: each of the biosynthetic steps, the functions and roles of the phospholipid products PC and PE, and how the Kennedy pathway has the potential of being a chemotherapeutic target against cancer and various infectious diseases.
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Affiliation(s)
- Federica Gibellini
- Centre for Biomolecular Sciences, University of St. Andrews, North Haugh, St. Andrews, Fife, Scotland, UK
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RICHMOND GREGORYS, GIBELLINI FEDERICA, YOUNG SIMONA, MAJOR LOUISE, DENTON HELEN, LILLEY ALISON, SMITH TERRYK. Lipidomic analysis of bloodstream and procyclic form Trypanosoma brucei. Parasitology 2010; 137:1357-92. [PMID: 20602846 PMCID: PMC3744936 DOI: 10.1017/s0031182010000715] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The biological membranes of Trypanosoma brucei contain a complex array of phospholipids that are synthesized de novo from precursors obtained either directly from the host, or as catabolised endocytosed lipids. This paper describes the use of nanoflow electrospray tandem mass spectrometry and high resolution mass spectrometry in both positive and negative ion modes, allowing the identification of approximately 500 individual molecular phospholipids species from total lipid extracts of cultured bloodstream and procyclic form T. brucei. Various molecular species of all of the major subclasses of glycerophospholipids were identified including phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, and phosphatidylinositol as well as phosphatidic acid, phosphatidylglycerol and cardolipin, and the sphingolipids sphingomyelin, inositol phosphoceramide and ethanolamine phosphoceramide. The lipidomic data obtained in this study will aid future biochemical phenotyping of either genetically or chemically manipulated commonly used bloodstream and procyclic strains of Trypanosoma brucei. Hopefully this will allow a greater understanding of the bizarre world of lipids in this important human pathogen.
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Affiliation(s)
| | - FEDERICA GIBELLINI
- Centre for Biomolecular Sciences, The North Haugh, The University, St. Andrews, KY16 9ST, Scotland, U.K
| | - SIMON A. YOUNG
- Centre for Biomolecular Sciences, The North Haugh, The University, St. Andrews, KY16 9ST, Scotland, U.K
| | - LOUISE MAJOR
- Centre for Biomolecular Sciences, The North Haugh, The University, St. Andrews, KY16 9ST, Scotland, U.K
| | - HELEN DENTON
- Centre for Biomolecular Sciences, The North Haugh, The University, St. Andrews, KY16 9ST, Scotland, U.K
| | - ALISON LILLEY
- Centre for Biomolecular Sciences, The North Haugh, The University, St. Andrews, KY16 9ST, Scotland, U.K
| | - TERRY K. SMITH
- Centre for Biomolecular Sciences, The North Haugh, The University, St. Andrews, KY16 9ST, Scotland, U.K
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Zheng L, T'Kind R, Decuypere S, von Freyend SJ, Coombs GH, Watson DG. Profiling of lipids in Leishmania donovani using hydrophilic interaction chromatography in combination with Fourier transform mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2010; 24:2074-2082. [PMID: 20552712 DOI: 10.1002/rcm.4618] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
There is evidence from our current research on resistance to stibigluconate and from some previous observations that lipid composition may be altered in resistant Leishmania donovani and in order to explore this we required a comprehensive lipidomics method. Phospholipids can be analysed by direct infusion into a mass spectrometer and such methods can work very well. However, chromatographic methods can also be very effective and are extensively used. They potentially avoid ion suppression effects, associate lipid classes with a retention time range and deliver good quantitative accuracy. In the current study three chromatography columns were compared for their ability to separate different classes of lipid. Butylsilane (C-4), Zic-HILIC and a silica gel column were compared. The best results were obtained with a silica gel column used in hydrophilic interaction chromatography (HILIC) mode with a mobile phase gradient consisting of (A) 20% isopropyl alcohol (IPA) in acetonitrile (v/v) and (B) 20% IPA in 0.02 M ammonium formate. Using these conditions separate peaks were obtained for triglycerides (TG), phosphoinositols (PI), inositol phosphoceramides (IPC), phosphatidylethanolamines (PE), phosphatidylserines (PS), phosphatidylcholines (PC), sphingosines (SG), lysophosphatidyethanolamines (LPE) and lysophosphatidylcholines (LPC). The methodology was applied to the analysis of lipid extracts from Leishmania donovani and by coupling the chromatography with an LTQ Orbitrap mass spectrometer. It was possible to detect 188 lipid species in the extracts with the following breakdown: PC 59, PE 38, TG 35, PI 20, CPI 13, LPC 11, LPE 2 and SG 10. The fatty acid composition of the more abundant lipids was characterised by MS(2) and MS(3) experiments carried out by using an LCQ Deca low-resolution ion trap instrument coupled with the silica gel column. The separation of lipids into well-defined groups gives extra confidence in their identification and minimises the risk of ion suppression effects. High-resolution mass spectrometry was necessary in order to be able to differentiate between acyl- and acyl-alkyl-lipids.
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Affiliation(s)
- Liang Zheng
- Strathclyde Institute of Pharmacy and Biomedical and Sciences, University of Strathclyde, 27 Taylor Street, Glasgow G4 0NR, UK
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Déchamps S, Shastri S, Wengelnik K, Vial HJ. Glycerophospholipid acquisition in Plasmodium - a puzzling assembly of biosynthetic pathways. Int J Parasitol 2010; 40:1347-65. [PMID: 20600072 DOI: 10.1016/j.ijpara.2010.05.008] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2010] [Revised: 05/24/2010] [Accepted: 05/25/2010] [Indexed: 01/06/2023]
Abstract
Throughout the Plasmodium life cycle, malaria parasites repeatedly undergo rapid cellular growth and prolific divisions, necessitating intense membrane neogenesis and, in particular, the acquisition of high amounts of phospholipids. At the intraerythrocytic stage, glycerophospholipids are the main parasite membrane constituents, which mostly originate from the Plasmodium-encoded enzymatic machinery. Several proteins and entire pathways have been characterized and their features reported, thereby generating a global view of glycerophospholipid synthesis across Plasmodium spp. The malaria parasite displays a panoply of pathways that are seldom found together in a single organism. The major glycerophospholipids are synthesized via ancestral prokaryotic CDP-diacylglycerol-dependent pathways and eukaryotic-type de novo pathways. The parasite exhibits additional reactions that bridge some of these routes and are otherwise restricted to some organisms, such as plants, while base-exchange mechanisms are largely unexplored in Plasmodium. Marked differences between Plasmodium spp. have also been reported in phosphatidylcholine and phosphatidylethanolamine synthesis. Little is currently known about glycerophospholipid acquisition at non-erythrocytic stages, but recent data reveal that intrahepatocytic parasites, oocysts and sporozoites import various host lipids, and that de novo fatty acid synthesis is only crucial at the late liver stage. More studies on the different Plasmodium developmental stages are needed, to further assemble the different pieces of this glycerophospholipid synthesis puzzle, which contains highly promising therapeutic targets.
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Affiliation(s)
- Sandrine Déchamps
- Dynamique des Interactions Membranaires Normales et Pathologiques, UMR 5235, Centre National de la Recherche Scientifique (CNRS) - Universite Montpellier 2, cc 107, Place Eugene Bataillon, 34095 Montpellier Cedex 05, France
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Young SA, Smith TK. The essential neutral sphingomyelinase is involved in the trafficking of the variant surface glycoprotein in the bloodstream form of Trypanosoma brucei. Mol Microbiol 2010; 76:1461-82. [PMID: 20398210 PMCID: PMC2904498 DOI: 10.1111/j.1365-2958.2010.07151.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/22/2010] [Indexed: 12/26/2022]
Abstract
Sphingomyelin is the main sphingolipid in Trypanosoma brucei, the causative agent of African sleeping sickness. In vitro and in vivo characterization of the T. brucei neutral sphingomyelinase demonstrates that it is directly involved in sphingomyelin catabolism. Gene knockout studies in the bloodstream form of the parasite indicate that the neutral sphingomyelinase is essential for growth and survival, thus highlighting that the de novo biosynthesis of ceramide is unable to compensate for the loss of sphingomyelin catabolism. The phenotype of the conditional knockout has given new insights into the highly active endocytic and exocytic pathways in the bloodstream form of T. brucei. Hence, the formation of ceramide in the endoplasmic reticulum affects post-Golgi sorting and rate of deposition of newly synthesized GPI-anchored variant surface glycoprotein on the cell surface. This directly influences the corresponding rate of endocytosis, via the recycling endosomes, of pre-existing cell surface variant surface glycoprotein. The trypanosomes use this coupled endocytic and exocytic mechanism to maintain the cell density of its crucial variant surface glycoprotein protective coat. TbnSMase is therefore genetically validated as a drug target against African trypanosomes, and suggests that interfering with the endocytic transport of variant surface glycoprotein is a highly desirable strategy for drug development against African trypanosomasis.
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Affiliation(s)
- Simon A Young
- Biomolecular Science, The North Haugh, The University, St. AndrewsFife Scotland KY16 9ST, UK
| | - Terry K Smith
- Biomolecular Science, The North Haugh, The University, St. AndrewsFife Scotland KY16 9ST, UK
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Lipid metabolism in Trypanosoma brucei. Mol Biochem Parasitol 2010; 172:66-79. [PMID: 20382188 DOI: 10.1016/j.molbiopara.2010.04.001] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2010] [Revised: 03/31/2010] [Accepted: 04/01/2010] [Indexed: 11/28/2022]
Abstract
Trypanosoma brucei membranes consist of all major eukaryotic glycerophospholipid and sphingolipid classes. These are de novo synthesized from precursors obtained either from the host or from catabolised endocytosed lipids. In recent years, substantial progress has been made in the molecular and biochemical characterisation of several of these lipid biosynthetic pathways, using gene knockout or RNA interference strategies or by enzymatic characterization of individual reactions. Together with the completed genome, these studies have highlighted several possible differences between mammalian and trypanosome lipid biosynthesis that could be exploited for the development of drugs against the diseases caused by these parasites.
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Abstract
The post-genomics era has provided researchers with access to a new generation of tools for the global characterization and understanding of pathogen diversity. This review provides a critical summary of published Leishmania post-genomic research efforts to date, and discusses the potential impact of the addition of metabolomics to the post-genomic toolbox. Metabolomics aims at understanding biology by comprehensive metabolite profiling. We present an overview of the design and interpretation of metabolomics experiments in the context of Leishmania research. Sample preparation, measurement techniques, and bioinformatics analysis of the generated complex datasets are discussed in detail. To illustrate the concepts and the expected results of metabolomics analyses, we also present an overview of comparative metabolic profiles of drug-sensitive and drug-resistant Leishmania donovani clinical isolates.
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Zhang K, Beverley SM. Phospholipid and sphingolipid metabolism in Leishmania. Mol Biochem Parasitol 2009; 170:55-64. [PMID: 20026359 DOI: 10.1016/j.molbiopara.2009.12.004] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2009] [Revised: 12/09/2009] [Accepted: 12/09/2009] [Indexed: 01/15/2023]
Abstract
In many eukaryotes, phospholipids (PLs) and sphingolipids (SLs) are abundant membrane components and reservoirs for important signaling molecules. In Leishmania, the composition, metabolism, and function of PLs and SLs differ significantly from those in mammalian cells. Although only a handful of enzymes have been experimentally characterized, available data suggest many steps of PL/SL metabolism are critical for Leishmania viability and/or virulence, and could be a source for new drug targets. Further studies of genes involved in the synthesis (de novo and salvage) and degradation of PLs and SLs will reveal their diverse effects on Leishmania pathogenesis.
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Affiliation(s)
- Kai Zhang
- Department of Biological Sciences, Texas Tech University, Lubbock, TX 79409, USA.
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Smith TK, Vasileva N, Gluenz E, Terry S, Portman N, Kramer S, Carrington M, Michaeli S, Gull K, Rudenko G. Blocking variant surface glycoprotein synthesis in Trypanosoma brucei triggers a general arrest in translation initiation. PLoS One 2009; 4:e7532. [PMID: 19855834 PMCID: PMC2762041 DOI: 10.1371/journal.pone.0007532] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2009] [Accepted: 09/22/2009] [Indexed: 01/22/2023] Open
Abstract
Background The African trypanosome Trypanosoma brucei is covered with a dense layer of Variant Surface Glycoprotein (VSG), which protects it from lysis by host complement via the alternative pathway in the mammalian bloodstream. Blocking VSG synthesis by the induction of VSG RNAi triggers an unusually precise precytokinesis cell-cycle arrest. Methodology/Principal Findings Here, we characterise the cells arrested after the induction of VSG RNAi. We were able to rescue the VSG221 RNAi induced cell-cycle arrest through expression of a second different VSG (VSG117 which is not recognised by the VSG221 RNAi) from the VSG221 expression site. Metabolic labeling of the arrested cells showed that blocking VSG synthesis triggered a global translation arrest, with total protein synthesis reduced to less than 1–4% normal levels within 24 hours of induction of VSG RNAi. Analysis by electron microscopy showed that the translation arrest was coupled with rapid disassociation of ribosomes from the endoplasmic reticulum. Polysome analysis showed a drastic decrease in polysomes in the arrested cells. No major changes were found in levels of transcription, total RNA transcript levels or global amino acid concentrations in the arrested cells. Conclusions The cell-cycle arrest phenotype triggered by the induction of VSG221 RNAi is not caused by siRNA toxicity, as this arrest can be alleviated if a second different VSG is inserted downstream of the active VSG221 expression site promoter. Analysis of polysomes in the stalled cells showed that the translation arrest is mediated at the level of translation initiation rather than elongation. The cell-cycle arrest induced in the presence of a VSG synthesis block is reversible, suggesting that VSG synthesis and/or trafficking to the cell surface could be monitored during the cell-cycle as part of a specific cell-cycle checkpoint.
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Affiliation(s)
- Terry K. Smith
- Centre for Biomolecular Sciences, University of St. Andrews, Fife, Scotland, United Kingdom
| | - Nadina Vasileva
- The Peter Medawar Building for Pathogen Research, University of Oxford, Oxford, United Kingdom
| | - Eva Gluenz
- Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom
| | - Stephen Terry
- The Peter Medawar Building for Pathogen Research, University of Oxford, Oxford, United Kingdom
| | - Neil Portman
- Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom
| | - Susanne Kramer
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Mark Carrington
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | | | - Keith Gull
- Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom
| | - Gloria Rudenko
- The Peter Medawar Building for Pathogen Research, University of Oxford, Oxford, United Kingdom
- * E-mail:
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