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Lee J, Matuschewski K, van Dooren G, Maier AG, Rug M. Lipid droplet dynamics are essential for the development of the malaria parasite Plasmodium falciparum. J Cell Sci 2024; 137:jcs262162. [PMID: 38962997 DOI: 10.1242/jcs.262162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2024] [Accepted: 06/26/2024] [Indexed: 07/05/2024] Open
Abstract
Lipid droplets (LDs) are organelles that are central to lipid and energy homeostasis across all eukaryotes. In the malaria-causing parasite Plasmodium falciparum the roles of LDs in lipid acquisition from its host cells and their metabolism are poorly understood, despite the high demand for lipids in parasite membrane synthesis. We systematically characterised LD size, composition and dynamics across the disease-causing blood infection. Applying split fluorescence emission analysis and three-dimensional (3D) focused ion beam-scanning electron microscopy (FIB-SEM), we observed a decrease in LD size in late schizont stages. LD contraction likely signifies a switch from lipid accumulation to lipid utilisation in preparation for parasite egress from host red blood cells. We demonstrate connections between LDs and several parasite organelles, pointing to potential functional interactions. Chemical inhibition of triacylglyerol (TAG) synthesis or breakdown revealed essential LD functions for schizogony and in counteracting lipid toxicity. The dynamics of lipid synthesis, storage and utilisation in P. falciparum LDs might provide a target for new anti-malarial intervention strategies.
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Affiliation(s)
- Jiwon Lee
- Centre for Advanced Microscopy, The Australian National University, Canberra ACT, 2601, Australia
- Research School of Biology, The Australian National University, Canberra ACT, 2601, Australia
| | - Kai Matuschewski
- Molecular Parasitology, Humboldt University, 10099 Berlin, Germany
| | - Giel van Dooren
- Research School of Biology, The Australian National University, Canberra ACT, 2601, Australia
| | - Alexander G Maier
- Research School of Biology, The Australian National University, Canberra ACT, 2601, Australia
| | - Melanie Rug
- Centre for Advanced Microscopy, The Australian National University, Canberra ACT, 2601, Australia
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2
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Leussa ANN, Rautenbach M. Antiplasmodial Cyclodecapeptides from Tyrothricin Share a Target with Chloroquine. Antibiotics (Basel) 2022; 11:antibiotics11060801. [PMID: 35740207 PMCID: PMC9219824 DOI: 10.3390/antibiotics11060801] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Revised: 06/03/2022] [Accepted: 06/09/2022] [Indexed: 12/10/2022] Open
Abstract
Previous research found that the six major cyclodecapeptides from the tyrothricin complex, produced by Brevibacillus parabrevis, showed potent activity against chloroquine sensitive (CQS) Plasmodium falciparum. The identity of the aromatic residues in the aromatic dipeptide unit in cyclo-(D-Phe1-Pro2-(Phe3/Trp3)-D-Phe4/D-Trp4)-Asn5-Gln6-(Tyr7/Phe7/Trp7)-Val8-(Orn9/Lys9)-Leu10 was proposed to have an important role in activity. CQS and resistant (CQR) P. falciparum strains were challenged with three representative cyclodecapeptides. Our results confirmed that cyclodecapeptides from tyrothricin had significantly higher antiplasmodial activity than the analogous gramicidin S, rivaling that of CQ. However, the previously hypothesized size and hydrophobicity dependent activity for these peptides did not hold true for P. falciparum strains, other than for the CQS 3D7 strain. The Tyr7 in tyrocidine A (TrcA) with Phe3-D-Phe4 seem to be related with loss in activity correlating with CQ antagonism and resistance, indicating a shared target and/or resistance mechanism in which the phenolic groups play a role. Phe7 in phenycidine A, the second peptide containing Phe3-D-Phe4, also showed CQ antagonism. Conversely, Trp7 in tryptocidine C (TpcC) with Trp3-D-Trp4 showed improved peptide selectivity and activity towards the more resistant strains, without overt antagonism towards CQ. However, TpcC lead to similar parasite stage inhibition and parasite morphology changes than previously observed for TrcA. The disorganization of chromatin packing and neutral lipid structures, combined with amorphous hemozoin crystals, could account for halted growth in late trophozoite/early schizont stage and the nanomolar non-lytic activity of these peptides. These targets related to CQ antagonism, changes in neural lipid distribution, leading to hemozoin malformation, indicate that the tyrothricin cyclodecapeptides and CQ share a target in the malaria parasite. The differing activities of these cyclic peptides towards CQS and CQR P. falciparum strains could be due to variable target interaction in multiple modes of activity. This indicated that the cyclodecapeptide activity and parasite resistance response depended on the aromatic residues in positions 3, 4 and 7. This new insight on these natural cyclic decapeptides could also benefit the design of unique small peptidomimetics in which activity and resistance can be modulated.
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3
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Matz JM. Plasmodium’s bottomless pit: properties and functions of the malaria parasite's digestive vacuole. Trends Parasitol 2022; 38:525-543. [DOI: 10.1016/j.pt.2022.02.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 02/21/2022] [Accepted: 02/21/2022] [Indexed: 11/30/2022]
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Ramaprasad A, Burda PC, Calvani E, Sait AJ, Palma-Duran SA, Withers-Martinez C, Hackett F, Macrae J, Collinson L, Gilberger TW, Blackman MJ. A choline-releasing glycerophosphodiesterase essential for phosphatidylcholine biosynthesis and blood stage development in the malaria parasite. eLife 2022; 11:82207. [PMID: 36576255 PMCID: PMC9886279 DOI: 10.7554/elife.82207] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Accepted: 12/23/2022] [Indexed: 12/29/2022] Open
Abstract
The malaria parasite Plasmodium falciparum synthesizes significant amounts of phospholipids to meet the demands of replication within red blood cells. De novo phosphatidylcholine (PC) biosynthesis via the Kennedy pathway is essential, requiring choline that is primarily sourced from host serum lysophosphatidylcholine (lysoPC). LysoPC also acts as an environmental sensor to regulate parasite sexual differentiation. Despite these critical roles for host lysoPC, the enzyme(s) involved in its breakdown to free choline for PC synthesis are unknown. Here, we show that a parasite glycerophosphodiesterase (PfGDPD) is indispensable for blood stage parasite proliferation. Exogenous choline rescues growth of PfGDPD-null parasites, directly linking PfGDPD function to choline incorporation. Genetic ablation of PfGDPD reduces choline uptake from lysoPC, resulting in depletion of several PC species in the parasite, whilst purified PfGDPD releases choline from glycerophosphocholine in vitro. Our results identify PfGDPD as a choline-releasing glycerophosphodiesterase that mediates a critical step in PC biosynthesis and parasite survival.
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Affiliation(s)
- Abhinay Ramaprasad
- Malaria Biochemistry Laboratory, The Francis Crick InstituteLondonUnited Kingdom
| | - Paul-Christian Burda
- Centre for Structural Systems BiologyHamburgGermany,Bernhard Nocht Institute for Tropical MedicineHamburgGermany,University of HamburgHamburgGermany
| | - Enrica Calvani
- Metabolomics Science Technology Platform, The Francis Crick InstituteLondonUnited Kingdom
| | - Aaron J Sait
- Electron Microscopy Science Technology Platform, The Francis Crick InstituteLondonUnited Kingdom
| | | | | | - Fiona Hackett
- Malaria Biochemistry Laboratory, The Francis Crick InstituteLondonUnited Kingdom
| | - James Macrae
- Metabolomics Science Technology Platform, The Francis Crick InstituteLondonUnited Kingdom
| | - Lucy Collinson
- Electron Microscopy Science Technology Platform, The Francis Crick InstituteLondonUnited Kingdom
| | - Tim Wolf Gilberger
- Centre for Structural Systems BiologyHamburgGermany,Bernhard Nocht Institute for Tropical MedicineHamburgGermany,University of HamburgHamburgGermany
| | - Michael J Blackman
- Malaria Biochemistry Laboratory, The Francis Crick InstituteLondonUnited Kingdom,Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical MedicineLondonUnited Kingdom
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5
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Asad M, Yamaryo-Botté Y, Hossain ME, Thakur V, Jain S, Datta G, Botté CY, Mohmmed A. An essential vesicular-trafficking phospholipase mediates neutral lipid synthesis and contributes to hemozoin formation in Plasmodium falciparum. BMC Biol 2021; 19:159. [PMID: 34380472 PMCID: PMC8359613 DOI: 10.1186/s12915-021-01042-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 04/30/2021] [Indexed: 11/10/2022] Open
Abstract
Background Plasmodium falciparum is the pathogen responsible for the most devastating form of human malaria. As it replicates asexually in the erythrocytes of its human host, the parasite feeds on haemoglobin uptaken from these cells. Heme, a toxic by-product of haemoglobin utilization by the parasite, is neutralized into inert hemozoin in the food vacuole of the parasite. Lipid homeostasis and phospholipid metabolism are crucial for this process, as well as for the parasite’s survival and propagation within the host. P. falciparum harbours a uniquely large family of phospholipases, which are suggested to play key roles in lipid metabolism and utilization. Results Here, we show that one of the parasite phospholipase (P. falciparum lysophospholipase, PfLPL1) plays an essential role in lipid homeostasis linked with the haemoglobin degradation and heme conversion pathway. Fluorescence tagging showed that the PfLPL1 in infected blood cells localizes to dynamic vesicular structures that traffic from the host-parasite interface at the parasite periphery, through the cytosol, to get incorporated into a large vesicular lipid rich body next to the food-vacuole. PfLPL1 is shown to harbour enzymatic activity to catabolize phospholipids, and its transient downregulation in the parasite caused a significant reduction of neutral lipids in the food vacuole-associated lipid bodies. This hindered the conversion of heme, originating from host haemoglobin, into the hemozoin, and disrupted the parasite development cycle and parasite growth. Detailed lipidomic analyses of inducible knock-down parasites deciphered the functional role of PfLPL1 in generation of neutral lipid through recycling of phospholipids. Further, exogenous fatty-acids were able to complement downregulation of PfLPL1 to rescue the parasite growth as well as restore hemozoin levels. Conclusions We found that the transient downregulation of PfLPL1 in the parasite disrupted lipid homeostasis and caused a reduction in neutral lipids essentially required for heme to hemozoin conversion. Our study suggests a crucial link between phospholipid catabolism and generation of neutral lipids (TAGs) with the host haemoglobin degradation pathway. Supplementary Information The online version contains supplementary material available at 10.1186/s12915-021-01042-z.
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Affiliation(s)
- Mohd Asad
- International Centre for Genetic Engineering and Biotechnology, New Delhi, 110 067, India
| | - Yoshiki Yamaryo-Botté
- ApicoLipid Team, Institute for Advanced Biosciences, CNRS UMR5309, Université Grenoble Alpes, INSERM U1209, Grenoble, France
| | - Mohammad E Hossain
- International Centre for Genetic Engineering and Biotechnology, New Delhi, 110 067, India
| | - Vandana Thakur
- International Centre for Genetic Engineering and Biotechnology, New Delhi, 110 067, India
| | - Shaifali Jain
- International Centre for Genetic Engineering and Biotechnology, New Delhi, 110 067, India
| | - Gaurav Datta
- International Centre for Genetic Engineering and Biotechnology, New Delhi, 110 067, India
| | - Cyrille Y Botté
- ApicoLipid Team, Institute for Advanced Biosciences, CNRS UMR5309, Université Grenoble Alpes, INSERM U1209, Grenoble, France
| | - Asif Mohmmed
- International Centre for Genetic Engineering and Biotechnology, New Delhi, 110 067, India.
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6
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Bosch M, Sweet MJ, Parton RG, Pol A. Lipid droplets and the host-pathogen dynamic: FATal attraction? J Cell Biol 2021; 220:e202104005. [PMID: 34165498 PMCID: PMC8240858 DOI: 10.1083/jcb.202104005] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 06/02/2021] [Accepted: 06/03/2021] [Indexed: 02/06/2023] Open
Abstract
In the ongoing conflict between eukaryotic cells and pathogens, lipid droplets (LDs) emerge as a choke point in the battle for nutrients. While many pathogens seek the lipids stored in LDs to fuel an expensive lifestyle, innate immunity rewires lipid metabolism and weaponizes LDs to defend cells and animals. Viruses, bacteria, and parasites directly and remotely manipulate LDs to obtain substrates for metabolic energy, replication compartments, assembly platforms, membrane blocks, and tools for host colonization and/or evasion such as anti-inflammatory mediators, lipoviroparticles, and even exosomes. Host LDs counterattack such advances by synthesizing bioactive lipids and toxic nucleotides, organizing immune signaling platforms, and recruiting a plethora of antimicrobial proteins to provide a front-line defense against the invader. Here, we review the current state of this conflict. We will discuss why, when, and how LDs efficiently coordinate and precisely execute a plethora of immune defenses. In the age of antimicrobial resistance and viral pandemics, understanding innate immune strategies developed by eukaryotic cells to fight and defeat dangerous microorganisms may inform future anti-infective strategies.
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Affiliation(s)
- Marta Bosch
- Lipid Trafficking and Disease Group, Institut d’Investigacions Biomèdiques August Pi i Sunyer, Barcelona, Spain
- Department of Biomedical Sciences, Faculty of Medicine, Universitat de Barcelona, Barcelona, Spain
| | - Matthew J. Sweet
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Australia
- Centre for Inflammation and Disease Research, Institute for Molecular Bioscience, University of Queensland, Brisbane, Australia
- Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, Australia
| | - Robert G. Parton
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Australia
- Centre for Microscopy and Microanalysis, University of Queensland, Brisbane, Australia
| | - Albert Pol
- Lipid Trafficking and Disease Group, Institut d’Investigacions Biomèdiques August Pi i Sunyer, Barcelona, Spain
- Department of Biomedical Sciences, Faculty of Medicine, Universitat de Barcelona, Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats, Barcelona, Spain
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7
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Tavares VDS, de Castro MV, Souza RDSO, Gonçalves IKA, Lima JB, Borges VDM, Araújo-Santos T. Lipid droplets of protozoan parasites: survival and pathogenicity. Mem Inst Oswaldo Cruz 2021; 116:e210270. [PMID: 35195194 PMCID: PMC8851939 DOI: 10.1590/0074-02760210270] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Accepted: 12/14/2021] [Indexed: 12/04/2022] Open
Abstract
Lipid droplets (LDs; lipid bodies) are intracellular sites of lipid storage and metabolism present in all cell types. Eukaryotic LDs are involved in eicosanoid production during several inflammatory conditions, including infection by protozoan parasites. In parasites, LDs play a role in the acquisition of cholesterol and other neutral lipids from the host. The number of LDs increases during parasite differentiation, and the biogenesis of these organelles use specific signaling pathways involving protein kinases. In addition, LDs are important in cellular protection against lipotoxicity. Recently, these organelles have been implicated in eicosanoid and specialised lipid metabolism. In this article, we revise the main functions of protozoan parasite LDs and discuss future directions in the comprehension of these organelles in the context of pathogen virulence.
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Affiliation(s)
| | | | | | | | - Jonilson Berlink Lima
- Universidade Federal do Oeste da Bahia, Brasil; Fundação Oswaldo Cruz-Fiocruz, Brasil
| | | | - Théo Araújo-Santos
- Universidade Federal do Oeste da Bahia, Brasil; Fundação Oswaldo Cruz-Fiocruz, Brasil
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8
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Giannangelo C, Siddiqui G, De Paoli A, Anderson BM, Edgington-Mitchell LE, Charman SA, Creek DJ. System-wide biochemical analysis reveals ozonide antimalarials initially act by disrupting Plasmodium falciparum haemoglobin digestion. PLoS Pathog 2020; 16:e1008485. [PMID: 32589689 PMCID: PMC7347234 DOI: 10.1371/journal.ppat.1008485] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 07/09/2020] [Accepted: 05/13/2020] [Indexed: 01/23/2023] Open
Abstract
Ozonide antimalarials, OZ277 (arterolane) and OZ439 (artefenomel), are synthetic peroxide-based antimalarials with potent activity against the deadliest malaria parasite, Plasmodium falciparum. Here we used a "multi-omics" workflow, in combination with activity-based protein profiling (ABPP), to demonstrate that peroxide antimalarials initially target the haemoglobin (Hb) digestion pathway to kill malaria parasites. Time-dependent metabolomic profiling of ozonide-treated P. falciparum infected red blood cells revealed a rapid depletion of short Hb-derived peptides followed by subsequent alterations in lipid and nucleotide metabolism, while untargeted peptidomics showed accumulation of longer Hb-derived peptides. Quantitative proteomics and ABPP assays demonstrated that Hb-digesting proteases were increased in abundance and activity following treatment, respectively. Ozonide-induced depletion of short Hb-derived peptides was less extensive in a drug-treated K13-mutant artemisinin resistant parasite line (Cam3.IIR539T) than in the drug-treated isogenic sensitive strain (Cam3.IIrev), further confirming the association between ozonide activity and Hb catabolism. To demonstrate that compromised Hb catabolism may be a primary mechanism involved in ozonide antimalarial activity, we showed that parasites forced to rely solely on Hb digestion for amino acids became hypersensitive to short ozonide exposures. Quantitative proteomics analysis also revealed parasite proteins involved in translation and the ubiquitin-proteasome system were enriched following drug treatment, suggestive of the parasite engaging a stress response to mitigate ozonide-induced damage. Taken together, these data point to a mechanism of action involving initial impairment of Hb catabolism, and indicate that the parasite regulates protein turnover to manage ozonide-induced damage.
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Affiliation(s)
- Carlo Giannangelo
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | - Ghizal Siddiqui
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | - Amanda De Paoli
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | - Bethany M. Anderson
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria, Australia
| | - Laura E. Edgington-Mitchell
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria, Australia
- Department of Maxillofacial Surgery, College of Dentistry, New York University, New York, New York, United States of America
| | - Susan A. Charman
- Centre for Drug Candidate Optimisation, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | - Darren J. Creek
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
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9
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Silva LMR, Lütjohann D, Hamid P, Velasquez ZD, Kerner K, Larrazabal C, Failing K, Hermosilla C, Taubert A. Besnoitia besnoiti infection alters both endogenous cholesterol de novo synthesis and exogenous LDL uptake in host endothelial cells. Sci Rep 2019; 9:6650. [PMID: 31040348 PMCID: PMC6491585 DOI: 10.1038/s41598-019-43153-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Accepted: 04/12/2019] [Indexed: 02/07/2023] Open
Abstract
Besnoitia besnoiti, an apicomplexan parasite of cattle being considered as emergent in Europe, replicates fast in host endothelial cells during acute infection and is in considerable need for energy, lipids and other building blocks for offspring formation. Apicomplexa are generally considered as defective in cholesterol synthesis and have to scavenge cholesterol from their host cells for successful replication. Therefore, we here analysed the influence of B. besnoiti on host cellular endogenous cholesterol synthesis and on sterol uptake from exogenous sources. GC-MS-based profiling of cholesterol-related sterols revealed enhanced cholesterol synthesis rates in B. besnoiti-infected cells. Accordingly, lovastatin and zaragozic acid treatments diminished tachyzoite production. Moreover, increased lipid droplet contents and enhanced cholesterol esterification was detected and inhibition of the latter significantly blocked parasite proliferation. Furthermore, artificial increase of host cellular lipid droplet disposability boosted parasite proliferation. Interestingly, lectin-like oxidized low density lipoprotein receptor 1 expression was upregulated in infected endothelial hostcells, whilst low density lipoproteins (LDL) receptor was not affected by parasite infection. However, exogenous supplementations with non-modified and acetylated LDL both boosted B. besnoiti proliferation. Overall, current data show that B. besnoiti simultaneously exploits both, endogenous cholesterol biosynthesis and cholesterol uptake from exogenous sources, during asexual replication.
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Affiliation(s)
- Liliana M R Silva
- Institute of Parasitology, Biomedical Research Center Seltersberg, Justus Liebig University Giessen, Schubertstr. 81, D-35392, Giessen, Germany.
| | - Dieter Lütjohann
- Institute for Clinical Chemistry and Clinical Pharmacology, University Clinics Bonn, Laboratory for Special Lipid Diagnostics/Center Internal Medicine/Building 26/UG 68, Sigmund-Freud-Str. 25, D-53127, Bonn, Germany
| | - Penny Hamid
- Institute of Parasitology, Biomedical Research Center Seltersberg, Justus Liebig University Giessen, Schubertstr. 81, D-35392, Giessen, Germany.,Department of Parasitology, Faculty of Veterinary Medicine, Universitas Gadjah Mada, Jl. Fauna No. 2 Karangmalang, 55281, Yogyakarta, Indonesia
| | - Zahady D Velasquez
- Institute of Parasitology, Biomedical Research Center Seltersberg, Justus Liebig University Giessen, Schubertstr. 81, D-35392, Giessen, Germany
| | - Katharina Kerner
- Institute for Hygiene and Infectious Diseases of Animals, Justus-Liebig-University, Giessen, Frankfurter Str. 85-89, D-35392, Germany
| | - Camilo Larrazabal
- Institute of Parasitology, Biomedical Research Center Seltersberg, Justus Liebig University Giessen, Schubertstr. 81, D-35392, Giessen, Germany
| | - Klaus Failing
- Unit for Biomathematics and Data Processing, Faculty of Veterinary Medicine, Justus Liebig University Giessen, Frankfurter Str. 95, D-35392, Giessen, Germany
| | - Carlos Hermosilla
- Institute of Parasitology, Biomedical Research Center Seltersberg, Justus Liebig University Giessen, Schubertstr. 81, D-35392, Giessen, Germany
| | - Anja Taubert
- Institute of Parasitology, Biomedical Research Center Seltersberg, Justus Liebig University Giessen, Schubertstr. 81, D-35392, Giessen, Germany
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10
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Taubert A, Silva LMR, Velásquez ZD, Larrazabal C, Lütjohann D, Hermosilla C. Modulation of cholesterol-related sterols during Eimeria bovis macromeront formation and impact of selected oxysterols on parasite development. Mol Biochem Parasitol 2018; 223:1-12. [PMID: 29909067 DOI: 10.1016/j.molbiopara.2018.06.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Revised: 06/12/2018] [Accepted: 06/12/2018] [Indexed: 11/16/2022]
Abstract
Obligate intracellular apicomplexan parasites are considered as deficient in cholesterol biosynthesis and scavenge cholesterol from their host cell in a parasite-specific manner. Compared to fast proliferating apicomplexan species producing low numbers of merozoites per host cell, (e. g. Toxoplasma gondii), the macromeront-forming protozoa Eimeria bovis is in extraordinary need for cholesterol for offspring production (≥ 170,000 merozoites I/macromeront). Interestingly, optimized in vitro E. bovis merozoite I production occurs under low foetal calf serum (FCS, 1.2%) supplementation. To analyze the impact of extensive E. bovis proliferation on host cellular sterol metabolism we here compared the sterol profiles of E. bovis-infected primary endothelial host cells grown under optimized (1.2% FCS) and non-optimized (10% FCS) cell culture conditions. Therefore, several sterols indicating endogenous de novo cholesterol synthesis, cholesterol conversion and sterol uptake (phytosterols) were analyzed via GC-MS-based approaches. Overall, significantly enhanced levels of phytosterols were detected in both FCS conditions indicating infection-triggered sterol uptake from extracellular sources as a major pathway of sterol acquisition. Interestingly, a simultaneous induction of endogenous cholesterol synthesis based on increased levels of distinct cholesterol precursors was only observed in case of optimized parasite proliferation indicating a parasite proliferation-dependent effect. Considering side-chain oxysterols, 25 hydroxycholesterol levels were selectively found increased in E. bovis-infected host cells, while 24 hydroxycholesterol and 27 hydroxycholesterol contents were not significantly altered by infection. Exogenous treatments with 25 hydroxycholesterol, 27 hydroxycholesterol, and 7 ketocholesterol revealed significant adverse effects on E. bovis intracellular development. Thus, the number and size of developing macromeronts and merozoite I production was significantly reduced indicating that these oxysterols bear direct or indirect antiparasitic properties. Overall, the current data indicate parasite-driven changes in the host cellular sterol profile reflecting the huge demand of E. bovis for cholesterol during macromeront formation and its versatility in the acquisition of cholesterol sources.
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Affiliation(s)
- A Taubert
- Institute of Parasitology, Biomedical Research Center Seltersberg, Justus Liebig University Giessen, Schubertstr. 81, 35392 Giessen, Germany.
| | - L M R Silva
- Institute of Parasitology, Biomedical Research Center Seltersberg, Justus Liebig University Giessen, Schubertstr. 81, 35392 Giessen, Germany.
| | - Z D Velásquez
- Institute of Parasitology, Biomedical Research Center Seltersberg, Justus Liebig University Giessen, Schubertstr. 81, 35392 Giessen, Germany.
| | - C Larrazabal
- Institute of Parasitology, Biomedical Research Center Seltersberg, Justus Liebig University Giessen, Schubertstr. 81, 35392 Giessen, Germany.
| | - D Lütjohann
- Institute of Clinical Chemistry and Clinical Pharmacology, University Clinics of Bonn, Sigmund-Freud-Str. 25, 53127 Bonn, Germany.
| | - C Hermosilla
- Institute of Parasitology, Biomedical Research Center Seltersberg, Justus Liebig University Giessen, Schubertstr. 81, 35392 Giessen, Germany.
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11
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Vallochi AL, Teixeira L, Oliveira KDS, Maya-Monteiro CM, Bozza PT. Lipid Droplet, a Key Player in Host-Parasite Interactions. Front Immunol 2018; 9:1022. [PMID: 29875768 PMCID: PMC5974170 DOI: 10.3389/fimmu.2018.01022] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Accepted: 04/24/2018] [Indexed: 12/18/2022] Open
Abstract
Lipid droplets (lipid bodies, LDs) are dynamic organelles that have important roles in regulating lipid metabolism, energy homeostasis, cell signaling, membrane trafficking, and inflammation. LD biogenesis, composition, and functions are highly regulated and may vary according to the stimuli, cell type, activation state, and inflammatory environment. Increased cytoplasmic LDs are frequently observed in leukocytes and other cells in a number of infectious diseases. Accumulating evidence reveals LDs participation in fundamental mechanisms of host-pathogen interactions, including cell signaling and immunity. LDs are sources of eicosanoid production, and may participate in different aspects of innate signaling and antigen presentation. In addition, intracellular pathogens evolved mechanisms to subvert host metabolism and may use host LDs, as ways of immune evasion and nutrients source. Here, we review mechanisms of LDs biogenesis and their contributions to the infection progress, and discuss the latest discoveries on mechanisms and pathways involving LDs roles as regulators of the immune response to protozoan infection.
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Affiliation(s)
- Adriana Lima Vallochi
- Laboratório de Imunofarmacologia, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz (FIOCRUZ), Rio de Janeiro, Brazil
| | | | | | | | - Patricia T. Bozza
- Laboratório de Imunofarmacologia, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz (FIOCRUZ), Rio de Janeiro, Brazil
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12
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Phospholipases during membrane dynamics in malaria parasites. Int J Med Microbiol 2017; 308:129-141. [PMID: 28988696 DOI: 10.1016/j.ijmm.2017.09.015] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Revised: 09/15/2017] [Accepted: 09/19/2017] [Indexed: 12/26/2022] Open
Abstract
Plasmodium parasites, the causative agents of malaria, display a well-regulated lipid metabolism required to ensure their survival in the human host as well as in the mosquito vector. The fine-tuning of lipid metabolic pathways is particularly important for the parasites during the rapid erythrocytic infection cycles, and thus enzymes involved in lipid metabolic processes represent prime targets for malaria chemotherapeutics. While plasmodial enzymes involved in lipid synthesis and acquisition have been studied in the past, to date not much is known about the roles of phospholipases for proliferation and transmission of the malaria parasite. These phospholipid-hydrolyzing esterases are crucial for membrane dynamics during host cell infection and egress by the parasite as well as for replication and cell signaling, and thus they are considered important virulence factors. In this review, we provide a comprehensive bioinformatic analysis of plasmodial phospholipases identified to date. We further summarize previous findings on the lipid metabolism of Plasmodium, highlight the roles of phospholipases during parasite life-cycle progression, and discuss the plasmodial phospholipases as potential targets for malaria therapy.
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13
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Tran PN, Brown SHJ, Rug M, Ridgway MC, Mitchell TW, Maier AG. Changes in lipid composition during sexual development of the malaria parasite Plasmodium falciparum. Malar J 2016; 15:73. [PMID: 26852399 PMCID: PMC4744411 DOI: 10.1186/s12936-016-1130-z] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Accepted: 01/23/2016] [Indexed: 01/13/2023] Open
Abstract
Background The development of differentiated sexual stages (gametocytes) within human red blood cells is essential for the propagation of the malaria parasite, since only mature gametocytes will survive in the mosquito’s midgut. Hence gametocytogenesis is a pre-requisite for transmission of the disease. Physiological changes involved in sexual differentiation are still enigmatic. In particular the lipid metabolism—despite being central to cellular regulation and development—is not well explored. Methods Here the lipid profiles of red blood cells infected with the five different sexual stages of Plasmodium falciparum were analysed by mass spectrometry and compared to those from uninfected and asexual trophozoite infected erythrocytes. Results Fundamental differences between erythrocytes infected with the different parasite stages were revealed. In mature gametocytes many lipids that decrease in the trophozoite and early gametocyte infected red blood cells are regained. In particular, regulators of membrane fluidity, cholesterol and sphingomyelin, increased significantly during gametocyte maturation. Neutral lipids (serving mainly as caloriometric reserves) increased from 3 % of total lipids in uninfected to 27 % in stage V gametocyte infected red blood cells. The major membrane lipid class (phospholipids) decreased during gametocyte development. Conclusions The lipid profiles of infected erythrocytes are characteristic for the particular parasite life cycle and maturity stages of gametocytes. The obtained lipid profiles are crucial in revealing the lipid metabolism of malaria parasites and identifying targets to interfere with this deadly disease. Electronic supplementary material The online version of this article (doi:10.1186/s12936-016-1130-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Phuong N Tran
- Research School of Biology, The Australian National University, Canberra, ACT, Australia. .,La Trobe Institute of Molecular Science, La Trobe University, Melbourne, VIC, Australia.
| | - Simon H J Brown
- School of Medicine and Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW, Australia.
| | - Melanie Rug
- Research School of Biology, The Australian National University, Canberra, ACT, Australia. .,Centre for Advanced Microscopy, The Australian National University, Canberra, ACT, Australia.
| | - Melanie C Ridgway
- Research School of Biology, The Australian National University, Canberra, ACT, Australia.
| | - Todd W Mitchell
- School of Medicine and Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW, Australia.
| | - Alexander G Maier
- Research School of Biology, The Australian National University, Canberra, ACT, Australia.
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Soupene E, Kao J, Cheng DH, Wang D, Greninger AL, Knudsen GM, DeRisi JL, Kuypers FA. Association of NMT2 with the acyl-CoA carrier ACBD6 protects the N-myristoyltransferase reaction from palmitoyl-CoA. J Lipid Res 2016; 57:288-98. [PMID: 26621918 PMCID: PMC4727424 DOI: 10.1194/jlr.m065003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Indexed: 01/13/2023] Open
Abstract
The covalent attachment of a 14-carbon aliphatic tail on a glycine residue of nascent translated peptide chains is catalyzed in human cells by two N-myristoyltransferase (NMT) enzymes using the rare myristoyl-CoA (C(14)-CoA) molecule as fatty acid donor. Although, NMT enzymes can only transfer a myristate group, they lack specificity for C(14)-CoA and can also bind the far more abundant palmitoyl-CoA (C(16)-CoA) molecule. We determined that the acyl-CoA binding protein, acyl-CoA binding domain (ACBD)6, stimulated the NMT reaction of NMT2. This stimulatory effect required interaction between ACBD6 and NMT2, and was enhanced by binding of ACBD6 to its ligand, C(18:2)-CoA. ACBD6 also interacted with the second human NMT enzyme, NMT1. The presence of ACBD6 prevented competition of the NMT reaction by C(16)-CoA. Mutants of ACBD6 that were either deficient in ligand binding to the N-terminal ACBD or unable to interact with NMT2 did not stimulate activity of NMT2, nor could they protect the enzyme from utilizing the competitor C(16)-CoA. These results indicate that ACBD6 can locally sequester C(16)-CoA and prevent its access to the enzyme binding site via interaction with NMT2. Thus, the ligand binding properties of the NMT/ACBD6 complex can explain how the NMT reaction can proceed in the presence of the very abundant competitive substrate, C(16)-CoA.
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Affiliation(s)
- Eric Soupene
- Children's Hospital Oakland Research Institute, Oakland, CA
| | - Joseph Kao
- Children's Hospital Oakland Research Institute, Oakland, CA
| | - Daniel H Cheng
- Children's Hospital Oakland Research Institute, Oakland, CA
| | - Derek Wang
- Children's Hospital Oakland Research Institute, Oakland, CA
| | - Alexander L Greninger
- Department of Biochemistry and Biophysics, University of California at San Francisco and Howard Hughes Medical Institute, San Francisco, CA
| | - Giselle M Knudsen
- Department of Pharmaceutical Chemistry, University of California at San Francisco, San Francisco, CA
| | - Joseph L DeRisi
- Department of Biochemistry and Biophysics, University of California at San Francisco and Howard Hughes Medical Institute, San Francisco, CA
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15
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Hamid PH, Hirzmann J, Kerner K, Gimpl G, Lochnit G, Hermosilla CR, Taubert A. Eimeria bovis infection modulates endothelial host cell cholesterol metabolism for successful replication. Vet Res 2015; 46:100. [PMID: 26395984 PMCID: PMC4579583 DOI: 10.1186/s13567-015-0230-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Accepted: 08/04/2015] [Indexed: 11/10/2022] Open
Abstract
During first merogony Eimeria bovis forms large macromeronts in endothelial host cells containing >120 000 merozoites I. During multiplication, large amounts of cholesterol are indispensable for the enormous offspring membrane production. Cholesterol auxotrophy was proven for other apicomplexan parasites. Consequently they scavenge cholesterol from their host cell apparently in a parasite-specific manner. We here analyzed the influence of E. bovis infection on endothelial host cell cholesterol metabolism and found considerable differences to other coccidian parasites. Overall, free cholesterol significantly accumulated in E. bovis infected host cells. Furthermore, a striking increase of lipid droplet formation was observed within immature macromeronts. Artificial host cell lipid droplet enrichment significantly improved E. bovis merozoite I production confirming the key role of lipid droplet contents for optimal parasite proliferation. The transcription of several genes being involved in both, cholesterol de novo biosynthesis and low density lipoprotein-(LDL) mediated uptake, was significantly up-regulated at a time in infected cells suggesting a simultaneous exploitation of these two cholesterol acquisition pathways. E. bovis scavenges LDL-derived cholesterol apparently through significantly increased levels of surface LDL receptor abundance and LDL binding to infected cells. Consequently, LDL supplementation significantly improved parasite replication. The up-regulation of the oxidized LDL receptor 1 furthermore identified this scavenger receptor as a key molecule in parasite-triggered LDL uptake. Moreover, cellular cholesterol processing was altered in infected cells as indicated by up-regulation of cholesterol-25-hydroxylase and sterol O-acyltransferase. Overall, these results show that E. bovis considerably exploits the host cell cholesterol metabolism to guarantee its massive intracellular growth and replication.
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Affiliation(s)
- Penny H Hamid
- Institute of Parasitology, Biomedical Research Centre, Justus Liebig University Giessen, Schubertstr. 81, D-35392, Giessen, Germany.
| | - Joerg Hirzmann
- Institute of Parasitology, Biomedical Research Centre, Justus Liebig University Giessen, Schubertstr. 81, D-35392, Giessen, Germany.
| | - Katharina Kerner
- Institute for Hygiene and Infectious Diseases of Animals, Justus LiebigUniversity Giessen, Frankfurter Str. 85-89, D-35392, Giessen, Germany.
| | - Gerald Gimpl
- Institute of Pharmacy and Biochemistry, Department of Biochemistry, Johann-Joachim-Becherweg 30, D-55099, Mainz, Germany.
| | - Guenter Lochnit
- Institute of Biochemistry, Justus Liebig University Giessen, Friedrichstr. 24, D-35392, Giessen, Germany.
| | - Carlos R Hermosilla
- Institute of Parasitology, Biomedical Research Centre, Justus Liebig University Giessen, Schubertstr. 81, D-35392, Giessen, Germany.
| | - Anja Taubert
- Institute of Parasitology, Biomedical Research Centre, Justus Liebig University Giessen, Schubertstr. 81, D-35392, Giessen, Germany.
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16
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Eguchi K, Fujiwara Y, Hayashida A, Horlad H, Kato H, Rotinsulu H, Losung F, Mangindaan REP, de Voogd NJ, Takeya M, Tsukamoto S. Manzamine A, a marine-derived alkaloid, inhibits accumulation of cholesterol ester in macrophages and suppresses hyperlipidemia and atherosclerosis in vivo. Bioorg Med Chem 2013; 21:3831-8. [PMID: 23665143 DOI: 10.1016/j.bmc.2013.04.025] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2013] [Revised: 04/06/2013] [Accepted: 04/08/2013] [Indexed: 11/28/2022]
Abstract
The formation of foam cells in macrophages plays an essential role in the progression of early atherosclerotic lesions and therefore its prevention is considered to be a promising target for the treatment of atherosclerosis. We found that an extract of the marine sponge Acanthostrongylophora ingens inhibited the foam cell formation induced by acetylated low-density lipoprotein (AcLDL) in human monocyte-derived macrophages, as measured based on the accumulation of cholesterol ester (CE). Bioassay-guided purification of inhibitors from the extract afforded manzamines. Manzamine A was the most potent inhibitor of foam cell formation, and also suppressed CE formation in Chinese hamster ovary cells overexpressing acyl-CoA:cholesterol acyl-transferase (ACAT)-1 or ACAT-2. In addition, manzamine A inhibited ACAT activity. Next, we orally administered manzamine A to apolipoprotein E (apoE)-deficient mice for 80 days, and found that total cholesterol, free cholesterol, LDL-cholesterol, and triglyceride levels in serum were significantly reduced and the area of atherosclerotic lesions in the aortic sinus was also substantially diminished. These findings clearly suggest that manzamine A suppresses hyperlipidemia and atherosclerosis in apoE-deficient mice by inhibiting ACAT and is therefore a promising lead compound in the prevention or treatment of atherosclerosis. Although manzamine A has been reported to show several biological activities, this is the first report of a suppressive effect of manzamine A on atherosclerosis in vivo.
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Affiliation(s)
- Keisuke Eguchi
- Department of Natural Medicines, Graduate School of Pharmaceutical Sciences, Kumamoto University, Oe-honmachi 5-1, Kumamoto 862-0973, Japan
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17
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Rub A, Arish M, Husain SA, Ahmed N, Akhter Y. Host-lipidome as a potential target of protozoan parasites. Microbes Infect 2013; 15:649-60. [PMID: 23811020 DOI: 10.1016/j.micinf.2013.06.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2013] [Revised: 04/13/2013] [Accepted: 06/18/2013] [Indexed: 12/24/2022]
Abstract
Host-lipidome caters parasite interaction by acting as first line of recognition, attachment on the cell surface, intracellular trafficking, and survival of the parasite inside the host cell. Here, we summarize how protozoan parasites exploit host-lipidome by suppressing, augmenting, engulfing, remodeling and metabolizing lipids to achieve successful parasitism inside the host.
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Affiliation(s)
- Abdur Rub
- Infection and Immunity Lab, Department of Biotechnology, Jamia Millia Islamia (A Central University), New Delhi 110025, India.
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18
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Lige B, Sampels V, Coppens I. Characterization of a second sterol-esterifying enzyme in Toxoplasma highlights the importance of cholesterol storage pathways for the parasite. Mol Microbiol 2013; 87:951-67. [PMID: 23374239 DOI: 10.1111/mmi.12142] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/20/2012] [Indexed: 11/28/2022]
Abstract
Lipid bodies are eukaryotic structures for temporary storage of neutral lipids such as acylglycerols and steryl esters. Fatty acyl-CoA and cholesterol are two substrates for cholesteryl ester (CE) synthesis via the ACAT reaction. The intracellular parasite Toxoplasma gondii is incapable of sterol synthesis and unremittingly scavenges cholesterol from mammalian host cells. We previously demonstrated that the parasite expresses a cholesteryl ester-synthesizing enzyme, TgACAT1. In this article, we identified and characterized a second ACAT-like enzyme, TgACAT2, which shares 56% identity with TgACAT1. Both enzymes are endoplasmic reticulum-associated and contribute to CE formation for storage in lipid bodies. While TgACAT1 preferentially utilizes palmitoyl-CoA, TgACAT2 has broader fatty acid specificity and produces more CE. Genetic ablation of each individual ACAT results in parasite growth impairment whereas dual ablation of ACAT1 and ACAT2 is not tolerated by Toxoplasma. ΔACAT1 and ΔACAT2 parasites have reduced CE levels, fewer lipid bodies, and accumulate free cholesterol, which causes injurious membrane effects. Mutant parasites are particularly vulnerable to ACAT inhibitors. This study underlines the important physiological role of ACAT enzymes to store cholesterol in a sterol-auxotrophic organism such as Toxoplasma, and furthermore opens up possibilities of exploiting TgACAT as targets for the development of antitoxoplasmosis drugs.
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Affiliation(s)
- Bao Lige
- Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD 21205, USA
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19
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Murphy DJ. The dynamic roles of intracellular lipid droplets: from archaea to mammals. PROTOPLASMA 2012; 249:541-85. [PMID: 22002710 DOI: 10.1007/s00709-011-0329-7] [Citation(s) in RCA: 170] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2011] [Accepted: 09/28/2011] [Indexed: 05/02/2023]
Abstract
During the past decade, there has been a paradigm shift in our understanding of the roles of intracellular lipid droplets (LDs). New genetic, biochemical and imaging technologies have underpinned these advances, which are revealing much new information about these dynamic organelles. This review takes a comparative approach by examining recent work on LDs across the whole range of biological organisms from archaea and bacteria, through yeast and Drosophila to mammals, including humans. LDs probably evolved originally in microorganisms as temporary stores of excess dietary lipid that was surplus to the immediate requirements of membrane formation/turnover. LDs then acquired roles as long-term carbon stores that enabled organisms to survive episodic lack of nutrients. In multicellular organisms, LDs went on to acquire numerous additional roles including cell- and organism-level lipid homeostasis, protein sequestration, membrane trafficking and signalling. Many pathogens of plants and animals subvert their host LD metabolism as part of their infection process. Finally, malfunctions in LDs and associated proteins are implicated in several degenerative diseases of modern humans, among the most serious of which is the increasingly prevalent constellation of pathologies, such as obesity and insulin resistance, which is associated with metabolic syndrome.
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Affiliation(s)
- Denis J Murphy
- Division of Biological Sciences, University of Glamorgan, Cardiff, CF37 4AT, UK.
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20
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Abstract
Lipid droplets (LDs) are highly dynamic cell organelles involved in energy homeostasis and membrane trafficking. Here, we review how select pathogens interact with LDs. Several RNA viruses use host LDs at different steps of their life cycle. Some intracellular bacteria and parasites usurp host LDs or encode their own lipid biosynthesis machinery, thus allowing production of LDs independently of their host. Although many mechanistic details of host/pathogen LD interactions are unknown, a picture emerges in which the unique cellular architecture and energy stored in LDs are important in the replication of diverse pathogens.
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Affiliation(s)
- Eva Herker
- Gladstone Institute of Virology and Immunology, San Francisco, California 94158, USA
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21
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Hoang AN, Sandlin RD, Omar A, Egan TJ, Wright DW. The neutral lipid composition present in the digestive vacuole of Plasmodium falciparum concentrates heme and mediates β-hematin formation with an unusually low activation energy. Biochemistry 2010; 49:10107-16. [PMID: 20979358 DOI: 10.1021/bi101397u] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In eukaryotic cells, neutral lipids serve as major energy storage molecules; however, in Plasmodium falciparum, a parasite responsible for causing malaria in humans, neutral lipids may have other functions during the intraerythrocytic stage of the parasite life cycle. Specifically, experimental data suggest that neutral lipid structures behave as a catalyst for the crystallization of hemozoin, a detoxification byproduct of several blood-feeding organisms, including malaria parasites. Synthetic neutral lipid droplets (SNLDs) were produced by depositing a lipid blend solution comprised of mono- and diglycerides onto an aqueous surface. These lipid droplets are able to mediate the production of brown pigments that are morphologically and chemically identical to hemozoin. The partitioning of heme into these SNLDs was examined by employing Nile Red, a lipid specific dye. Soluble ferriprotoporphyrin IX was observed to spontaneously localize to the lipid droplets, partitioning in a pH-dependent manner with an estimated log P of 2.6. Interestingly, the pH profile of heme partitioning closely resembles that of β-hematin formation. Differential scanning calorimetry and kinetic studies demonstrated that the SNLDs provide a unique environment that promotes hemozoin formation. SNLD-mediated formation of the malaria pigment displayed an activation energy barrier lower than those of individual lipid components. In particular, lipid droplets composed of diglycerides displayed activation barriers lower than those composed of monoglycerides. This difference was attributed to the greater fluidity of these lipids. In conjunction with the known pattern of lipid body proliferation, it is suggested that neutral lipid structures within the digestive vacuole not only are the location of in vivo hemozoin formation but are also essential for the survival of the parasite by functioning as a kinetically competent and site specific mediator for heme detoxification.
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Affiliation(s)
- Anh N Hoang
- Department of Chemistry, Vanderbilt University, Station B351822, Nashville, Tennessee 37235, United States
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22
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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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23
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Bozza PT, D’Avila H, Almeida PE, Magalhães KG, Molinaro R, Almeida CJ, Maya-Monteiro CM. Lipid droplets in host–pathogen interactions. ACTA ACUST UNITED AC 2009. [DOI: 10.2217/clp.09.63] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Accumulation of artemisinin trioxane derivatives within neutral lipids of Plasmodium falciparum malaria parasites is endoperoxide-dependent. Biochem Pharmacol 2008; 77:322-36. [PMID: 19022224 DOI: 10.1016/j.bcp.2008.10.015] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2008] [Revised: 10/07/2008] [Accepted: 10/09/2008] [Indexed: 11/21/2022]
Abstract
The antimalarial trioxanes, exemplified by the naturally occurring sesquiterpene lactone artemisinin and its semi-synthetic derivatives, contain an endoperoxide pharmacophore that lends tremendous potency against Plasmodium parasites. Despite decades of research, their mechanism of action remains unresolved. A leading model of anti-plasmodial activity hypothesizes that iron-mediated cleavage of the endoperoxide bridge generates cytotoxic drug metabolites capable of damaging cellular macromolecules. To probe the malarial targets of the endoperoxide drugs, we studied the distribution of fluorescent dansyl trioxane derivatives in living, intraerythrocytic-stage Plasmodium falciparum parasites using microscopic imaging. The fluorescent trioxanes rapidly accumulated in parasitized erythrocytes, localizing within digestive vacuole-associated neutral lipid bodies of trophozoites and schizonts, and surrounding the developing merozoite membranes. Artemisinin pre-treatment significantly reduced fluorescent labeling of neutral lipid bodies, while iron chelation increased non-specific cytoplasmic localization. To further explore the effects of endoperoxides on cellular lipids, we used an oxidation-sensitive BODIPY lipid probe to show the presence of artemisinin-induced peroxyl radicals in parasite membranes. Lipid extracts from artemisinin-exposed parasites contained increased amounts of free fatty acids and a novel cholesteryl ester. The cellular accumulation patterns and effects on lipids were entirely endoperoxide-dependent, as inactive dioxolane analogs lacking the endoperoxide moiety failed to label neutral lipid bodies or induce oxidative membrane damage. In the parasite digestive vacuole, neutral lipids closely associate with heme and promote hemozoin formation. We propose that the trioxane artemisinin and its derivatives are activated by heme-iron within the neutral lipid environment where they initiate oxidation reactions that damage parasite membranes.
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25
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Lipid bodies in innate immune response to bacterial and parasite infections. Int Immunopharmacol 2008; 8:1308-15. [DOI: 10.1016/j.intimp.2008.01.035] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2007] [Accepted: 01/02/2008] [Indexed: 01/06/2023]
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26
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Sherman IW. References. ADVANCES IN PARASITOLOGY 2008. [DOI: 10.1016/s0065-308x(08)00430-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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27
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Hemozoin: oil versus water. Parasitol Int 2007; 57:89-96. [PMID: 18373972 DOI: 10.1016/j.parint.2007.09.009] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2007] [Revised: 09/26/2007] [Accepted: 09/28/2007] [Indexed: 11/23/2022]
Abstract
Because the quinolines inhibit heme crystallization within the malaria parasite much work has focused on mechanism of formation and inhibition of hemozoin. Here we review the recent evidence for heme crystallization within lipids in diverse parasites and the new implications of a lipid site of crystallization for drug targeting. Within leukocytes hemozoin can generate toxic radical lipid metabolites, which may alter immune function or reduce deformability of uninfected erythrocytes.
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28
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Mazumdar J, Striepen B. Make it or take it: fatty acid metabolism of apicomplexan parasites. EUKARYOTIC CELL 2007; 6:1727-35. [PMID: 17715365 PMCID: PMC2043401 DOI: 10.1128/ec.00255-07] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Jolly Mazumdar
- Department of Cellular Biology, University of Georgia, Paul D Coverdell Center, Athens, GA 30602, USA
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29
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Pisciotta J, Coppens I, Tripathi A, Scholl P, Shuman J, Bajad S, Shulaev V, Sullivan D. The role of neutral lipid nanospheres in Plasmodium falciparum haem crystallization. Biochem J 2007; 402:197-204. [PMID: 17044814 PMCID: PMC1783988 DOI: 10.1042/bj20060986] [Citation(s) in RCA: 166] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The intraerythrocytic malaria parasite constructs an intracellular haem crystal, called haemozoin, within an acidic digestive vacuole where haemoglobin is degraded. Haem crystallization is the target of the widely used antimalarial quinoline drugs. The intracellular mechanism of molecular initiation of haem crystallization, whether by proteins, polar membrane lipids or by neutral lipids, has not been fully substantiated. In the present study, we show neutral lipid predominant nanospheres, which envelop haemozoin inside Plasmodium falciparum digestive vacuoles. Subcellular fractionation of parasite-derived haemozoin through a dense 1.7 M sucrose cushion identifies monoacylglycerol and diacylglycerol neutral lipids as well as some polar lipids in close association with the purified haemozoin. Global MS lipidomics detects monopalmitic glycerol and monostearic glycerol, but not mono-oleic glycerol, closely associated with haemozoin. The complex neutral lipid mixture rapidly initiates haem crystallization, with reversible pH-dependent quinoline inhibition associated with quinoline entry into the neutral lipid microenvironment. Neutral lipid nanospheres both enable haem crystallization in the presence of high globin concentrations and protect haem from H2O2 degradation. Conceptually, the present study shifts the intracellular microenvironment of haem crystallization and quinoline inhibition from a polar aqueous location to a non-polar neutral lipid nanosphere able to exclude water for efficient haem crystallization.
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Affiliation(s)
- John M. Pisciotta
- *Malaria Research Institute, W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street, Baltimore, MD 21205, U.S.A
| | - Isabelle Coppens
- *Malaria Research Institute, W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street, Baltimore, MD 21205, U.S.A
| | - Abhai K. Tripathi
- *Malaria Research Institute, W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street, Baltimore, MD 21205, U.S.A
| | - Peter F. Scholl
- †Department of Environmental Health Sciences, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street, Baltimore, MD 21205, U.S.A
| | - Joel Shuman
- ‡Virginia Bioinformatics Institute, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, U.S.A
| | - Sunil Bajad
- ‡Virginia Bioinformatics Institute, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, U.S.A
| | - Vladimir Shulaev
- ‡Virginia Bioinformatics Institute, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, U.S.A
| | - David J. Sullivan
- *Malaria Research Institute, W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street, Baltimore, MD 21205, U.S.A
- To whom correspondence should be addressed (email )
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Debierre-Grockiego F, Schofield L, Azzouz N, Schmidt J, Santos de Macedo C, Ferguson MAJ, Schwarz RT. Fatty acids from Plasmodium falciparum down-regulate the toxic activity of malaria glycosylphosphatidylinositols. Infect Immun 2006; 74:5487-96. [PMID: 16988223 PMCID: PMC1594897 DOI: 10.1128/iai.01934-05] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Plasmodium falciparum malaria kills roughly 2.5 million people, mainly children, annually. Much of this mortality is thought to arise from the actions of a malarial toxin. This toxin, identified as glycosylphosphatidylinositol (GPI), is a major pathogenicity determinant in malaria. A malarial molecule, Pfj, labeled by [3H]glucosamine like the GPIs, was identified as a non-GPI molecule. Here we show that Pfj is able to down-regulate tumor necrosis factor alpha (TNF-alpha) production induced by the GPI of P. falciparum. Mass spectrometry analysis showed that Pfj was not a single molecule but represented a number of molecules. Separation methods, such as cation-exchange chromatography and thin-layer chromatography, were used to isolate and identify the following four main fatty acids responsible for the inhibitory effect on TNF-alpha production: myristic, pentadecanoic, palmitic, and palmitoleic acids. This regulatory effect on cytokine production suggests that there is balanced bioactivity for the different categories of malarial lipids.
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31
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de Venevelles P, François Chich J, Faigle W, Lombard B, Loew D, Péry P, Labbé M. Study of proteins associated with the Eimeria tenella refractile body by a proteomic approach. Int J Parasitol 2006; 36:1399-407. [PMID: 16959255 DOI: 10.1016/j.ijpara.2006.06.018] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2006] [Revised: 06/19/2006] [Accepted: 06/23/2006] [Indexed: 11/21/2022]
Abstract
Refractile bodies (RB), whose function is still unknown, are specific structures of Eimeriidae parasites. In order to study their proteome, RB were purified from Eimeria tenella sporozoites by a new procedure using a reversible fixation followed by centrifugation. RB proteins were resolved by two-dimensional electrophoresis. Around 76 and 89 spots were detected on RB two-dimensional gels using gradients in the 3-10 and 4-7 range, respectively. RB proteins were located mainly between pH 5 and 7. RB gels were then compared with previously established maps of the entire sporozoite proteome. Proteins appearing in new spots were identified by mass spectrometry. Thirty protein isoforms were located in RB. Added to the already known RB proteins such as Eimepsin and SO7', the new RB proteins were defined as haloacid dehalogenase, hydrolase, subtilase, lactacte dehydrogenase or ubiquitin family proteins. The RB proteome analysis confirmed the hypothesis that this structure is a reservoir for proteins necessary to invasion but also suggests that RB have energetic and metabolic functions.
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Affiliation(s)
- Patrick de Venevelles
- Unité de Virologie et Immunologie Moléculaires UR892, Institut National de la Recherche Agronomique, 78350 Jouy-en-Josas, France
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32
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Wenk MR. Lipidomics of host-pathogen interactions. FEBS Lett 2006; 580:5541-51. [PMID: 16859687 DOI: 10.1016/j.febslet.2006.07.007] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2006] [Revised: 07/02/2006] [Accepted: 07/03/2006] [Indexed: 12/16/2022]
Abstract
The cell biology of intracellular pathogens (viruses, bacteria, eukaryotic parasites) has provided us with molecular information of host-pathogen interactions. As a result it is becoming increasingly evident that lipids play important roles at various stages of host-pathogen interactions. They act in first line recognition and host cell signaling during pathogen docking, invasion and intracellular trafficking. Lipid metabolism is a housekeeping function in energy homeostasis and biomembrane synthesis during pathogen replication and persistence. Lipids of enormous chemical diversity play roles as immunomodulatory factors. Thus, novel biochemical analytics in combination with cell and molecular biology are a promising recipe for dissecting the roles of lipids in host-pathogen interactions.
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Affiliation(s)
- Markus R Wenk
- Department of Biochemistry, National University of Singapore, Yong Loo Lin School of Medicine, 8 Medical Drive, Block MD7, Singapore 117597, Singapore.
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33
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Sehgal A, Bettiol S, Pypaert M, Wenk MR, Kaasch A, Blader IJ, Joiner KA, Coppens I. Peculiarities of host cholesterol transport to the unique intracellular vacuole containing Toxoplasma. Traffic 2006; 6:1125-41. [PMID: 16262724 DOI: 10.1111/j.1600-0854.2005.00348.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The intracellular protozoan Toxoplasma gondii is auxotrophic for low-density lipoprotein (LDL)-derived cholesterol (C). We previously showed that T. gondii scavenges this essential lipid from host endolysosomal compartments and that C delivery to the parasitophorous vacuole (PV) does not require transit through host Golgi or endoplasmic reticulum. In this study, we explore the itinerary of C from the host endolysosomes to the PV. Labeled C incorporated into LDL is rapidly detected in intravacuolar parasites and partially esterified by the parasites. In contrast to diverse mammalian organelles, the post-endolysosomal transfer of C to the PV does not involve the host plasma membrane as an intermediate. Nevertheless, the PV membrane is accessible to extracellular sterol acceptors, suggesting C trafficking from intracellular parasites to host plasma membrane. C movement to the PV requires temperatures permissive for vesicular transport, metabolic energy and functional microtubules. Host caveolae vesicles and the sterol carrier protein-2 do not participate in this process. Proteolytic treatment of purified PV or free parasites abolishes C acquisition by the parasites. Altogether, these results support a vesicular transport system from host endolysosomes to the PV, and a requirement for PV membrane and parasite plasma membrane proteins in C delivery to T. gondii.
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Affiliation(s)
- Alfica Sehgal
- Department of Internal Medicine, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
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34
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Kremer L, de Chastellier C, Dobson G, Gibson KJC, Bifani P, Balor S, Gorvel JP, Locht C, Minnikin DE, Besra GS. Identification and structural characterization of an unusual mycobacterial monomeromycolyl-diacylglycerol. Mol Microbiol 2005; 57:1113-26. [PMID: 16091048 DOI: 10.1111/j.1365-2958.2005.04717.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Systematic thin layer chromatographic (TLC) analysis of apolar lipids in Mycobacterium kansasii revealed the presence of a previously uncharacterized novel component. The product was ubiquitously found in a panel of M. kansasii clinical isolates, as well as other pathogenic and non-pathogenic mycobacterial species. TLC analysis of [(14)C]-acetate- or [(14)C]-glycerol-labelled M. kansasii cultures tentatively assigned the novel product as an unusual triacylglycerol-related lipid. Subsequent purification, followed by structural determination using (1)H-nuclear magnetic resonance (NMR) and electrospray mass spectrometry (ES/MS), led to the identification of this product as a monomeromycolyl-diacylglycerol (MMDAG). Treatment of M. kansasii with either isoniazid (INH), a well-known type II fatty acid synthase (FAS-II) and mycolic acid biosynthesis inhibitor, or tetrahydrolipstatin (THL), a drug approved for treating obesity, correlated with a reduced incorporation of [(14)C]-acetate into both mycolic acids and MMDAG. Addition of INH or THL to the cultures induced major morphological changes and, surprisingly, resulted in an increased number of lipid storage bodies, as determined by electron microscopy. The potent antimycobacterial activity of THL was confirmed against a variety of mycobacterial species, including INH-susceptible and -resistant Mycobacterium tuberculosis strains. Therefore, THL and other beta-lactones may be promising drugs for the development of new antitubercular therapy.
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Affiliation(s)
- Laurent Kremer
- Laboratoire des Mécanismes Moléculaires de la Pathogénie Microbienne, INSERM U629, Institut Pasteur de Lille, 1, rue du Prof. Calmette, F-59019 Lille, France.
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35
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Sonda S, Hehl AB. Lipid biology of Apicomplexa: perspectives for new drug targets, particularly for Toxoplasma gondii. Trends Parasitol 2005; 22:41-7. [PMID: 16300997 DOI: 10.1016/j.pt.2005.11.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2005] [Revised: 09/20/2005] [Accepted: 11/07/2005] [Indexed: 11/19/2022]
Abstract
Development of effective therapies for intracellular eukaryotic pathogens is a serious challenge, given the protected location of these pathogens and the similarity of their biology to that of the host. Identifying cellular processes that are unique to the parasite is therefore a crucial step towards defining appropriate drug targets. In the case of the apicomplexan parasite Toxoplasma gondii, the need to find alternative treatments is imperative because of the poor tolerability and frequent side-effects associated with existing therapeutic strategies. The discovery that the parasite uses lipid synthetic pathways which are different from, or absent in, the mammalian host is now driving a renewed interest in T. gondii lipid biology. Recent achievements in this field are promising and suggest that the elucidation of lipid pathways will provide new opportunities for designing potent antiparasitic strategies.
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Affiliation(s)
- Sabrina Sonda
- Institute of Parasitology, University of Zurich, Winterthurerstrasse 266a, CH-8057 Zurich, Switzerland.
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36
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McIntosh MT, Elliott DA, Joiner KA. Plasmodium falciparum: Discovery of peroxidase active organelles. Exp Parasitol 2005; 111:133-6. [PMID: 16039653 DOI: 10.1016/j.exppara.2005.06.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2004] [Revised: 06/02/2005] [Accepted: 06/07/2005] [Indexed: 11/19/2022]
Abstract
Staining with 3,3' diaminobenzidine tetrahydrochloride (DAB) is a common method used for the detection of peroxidases. Using this histochemical staining method in conjunction with transmission electron microscopy, we observed oxidation of DAB that was localized to a discrete set of organelles displaying morphological similarity to small (75-90 nm diameter) versions of higher eukaryotic microbodies or peroxisomes. These single membrane bounded organelles were characterized by an asymmetrical matrix capable of oxidizing DAB to an electron dense inclusion. Oxidation of DAB was further found to be dependent upon hydrogen peroxide (H2O2) as a substrate. Given a lack of peroxisomal import proteins and enzymes, it is unlikely that these represent conventional peroxisomes. Rather, they likely represent specialized organelles containing endogenous peroxidase or pseudo-peroxidase activity.
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Affiliation(s)
- Michael T McIntosh
- Department of Internal Medicine, Yale University School of Medicine, 333 Cedar Street, P.O. Box 20822, New Haven, CT 06520-8022, USA
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37
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Nishikawa Y, Quittnat F, Stedman TT, Voelker DR, Choi JY, Zahn M, Yang M, Pypaert M, Joiner KA, Coppens I. Host cell lipids control cholesteryl ester synthesis and storage in intracellular Toxoplasma. Cell Microbiol 2005; 7:849-67. [PMID: 15888087 DOI: 10.1111/j.1462-5822.2005.00518.x] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The intracellular protozoan Toxoplasma gondii lacks a de novo mechanism for cholesterol synthesis and therefore must scavenge this essential lipid from the host environment. In this study, we demonstrated that T. gondii diverts cholesterol from low-density lipoproteins for cholesteryl ester synthesis and storage in lipid bodies. We identified and characterized two isoforms of acyl-CoA:cholesterol acyltransferase (ACAT)-related enzymes, designated TgACAT1alpha and TgACAT1beta in T. gondii. Both proteins are coexpressed in the parasite, localized to the endoplasmic reticulum and participate in cholesteryl ester synthesis. In contrast to mammalian ACAT, TgACAT1alpha and TgACAT1beta preferentially incorporate palmitate into cholesteryl esters and present a broad sterol substrate affinity. Mammalian ACAT-deficient cells transfected with either TgACAT1alpha or TgACAT1beta are restored in their capability of cholesterol esterification. TgACAT1alpha produces steryl esters and forms lipid bodies after transformation in a Saccharomyces cerevisiae mutant strain lacking neutral lipids. In addition to their role as ACAT substrates, host fatty acids and low-density lipoproteins directly serve as Toxoplasma ACAT activators by stimulating cholesteryl ester synthesis and lipid droplet biogenesis. Free fatty acids significantly increase TgACAT1alpha mRNA levels. Selected cholesterol esterification inhibitors impair parasite growth by rapid disruption of plasma membrane. Altogether, these studies indicate that host lipids govern neutral lipid synthesis in Toxoplasma and that interference with mechanisms of host lipid storage is detrimental to parasite survival in mammalian cells.
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Affiliation(s)
- Yoshifumi Nishikawa
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06520, USA
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38
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Coppens I, Vielemeyer O. Insights into unique physiological features of neutral lipids in Apicomplexa: from storage to potential mediation in parasite metabolic activities. Int J Parasitol 2005; 35:597-615. [PMID: 15862574 DOI: 10.1016/j.ijpara.2005.01.009] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2004] [Revised: 01/05/2005] [Accepted: 01/13/2005] [Indexed: 01/18/2023]
Abstract
The fast intracellular multiplication of apicomplexan parasites including Toxoplasma and Plasmodium, requires large amounts of lipids necessary for the membrane biogenesis of new progenies. Hence, the study of lipids is fundamental in order to understand the biology and pathogenesis of these deadly organisms. Much has been reported on the importance of polar lipids, e.g. phospholipids in Plasmodium. Comparatively, little attention has been paid to the metabolism of neutral lipids, including sterols, steryl esters and acylglycerols. In eukaryotic cells, free sterols are membrane components whereas steryl esters and acylglycerols are stored in cytosolic lipid inclusions. The first part of this review describes the recent advances in neutral lipid synthesis and storage in Toxoplasma and Plasmodium. New potential pharmacological targets in the pathways producing neutral lipids are outlined. In addition to lipid bodies, Apicomplexa contain unique secretory organelles involved in parasite invasion named rhoptries. These compartments appear to sequester most of the cholesterol found in the exocytic pathway. The second part of the review focuses on rhoptry cholesterol and its potential roles in the biogenesis, structural organisation and function of these unique organelles among eukaryotes.
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Affiliation(s)
- Isabelle Coppens
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205-2223, USA.
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39
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Martin RE, Henry RI, Abbey JL, Clements JD, Kirk K. The 'permeome' of the malaria parasite: an overview of the membrane transport proteins of Plasmodium falciparum. Genome Biol 2005; 6:R26. [PMID: 15774027 PMCID: PMC1088945 DOI: 10.1186/gb-2005-6-3-r26] [Citation(s) in RCA: 129] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2004] [Revised: 12/31/2004] [Accepted: 01/28/2005] [Indexed: 11/24/2022] Open
Abstract
Bioinformatic and expression analyses attribute putative functions to transporters and channels encoded by the Plasmodium falciparum genome. The malaria parasite has substantially more membrane transport proteins than previously thought. Background The uptake of nutrients, expulsion of metabolic wastes and maintenance of ion homeostasis by the intraerythrocytic malaria parasite is mediated by membrane transport proteins. Proteins of this type are also implicated in the phenomenon of antimalarial drug resistance. However, the initial annotation of the genome of the human malaria parasite Plasmodium falciparum identified only a limited number of transporters, and no channels. In this study we have used a combination of bioinformatic approaches to identify and attribute putative functions to transporters and channels encoded by the malaria parasite, as well as comparing expression patterns for a subset of these. Results A computer program that searches a genome database on the basis of the hydropathy plots of the corresponding proteins was used to identify more than 100 transport proteins encoded by P. falciparum. These include all the transporters previously annotated as such, as well as a similar number of candidate transport proteins that had escaped detection. Detailed sequence analysis enabled the assignment of putative substrate specificities and/or transport mechanisms to all those putative transport proteins previously without. The newly-identified transport proteins include candidate transporters for a range of organic and inorganic nutrients (including sugars, amino acids, nucleosides and vitamins), and several putative ion channels. The stage-dependent expression of RNAs for 34 candidate transport proteins of particular interest are compared. Conclusion The malaria parasite possesses substantially more membrane transport proteins than was originally thought, and the analyses presented here provide a range of novel insights into the physiology of this important human pathogen.
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Affiliation(s)
- Rowena E Martin
- School of Biochemistry and Molecular Biology, Faculty of Science, The Australian National University, Canberra, ACT 0200, Australia
| | - Roselani I Henry
- School of Biochemistry and Molecular Biology, Faculty of Science, The Australian National University, Canberra, ACT 0200, Australia
| | - Janice L Abbey
- School of Biochemistry and Molecular Biology, Faculty of Science, The Australian National University, Canberra, ACT 0200, Australia
| | - John D Clements
- School of Biochemistry and Molecular Biology, Faculty of Science, The Australian National University, Canberra, ACT 0200, Australia
- Division of Neuroscience, The John Curtin School of Medical Research, The Australian National University, Canberra, ACT 0200, Australia
| | - Kiaran Kirk
- School of Biochemistry and Molecular Biology, Faculty of Science, The Australian National University, Canberra, ACT 0200, Australia
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40
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Jackson KE, Klonis N, Ferguson DJP, Adisa A, Dogovski C, Tilley L. Food vacuole-associated lipid bodies and heterogeneous lipid environments in the malaria parasite, Plasmodium falciparum. Mol Microbiol 2004; 54:109-22. [PMID: 15458409 DOI: 10.1111/j.1365-2958.2004.04284.x] [Citation(s) in RCA: 125] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The malaria parasite Plasmodium falciparum induces a sixfold increase in the phospholipid content of infected erythrocytes during its intraerythrocytic growth. We have characterized the lipid environments in parasitized erythrocyte using the hydrophobic probe, Nile Red. Spectral imaging with a confocal microscope revealed heterogeneous lipid environments in parasite-infected erythrocytes. An insight into the nature of these environments was gained by comparing these spectra with those of triacylglycerol/phospholipid emulsions and phospholipid membranes. Using this approach, we identified a population of intensely stained particles of a few hundred nanometers in size that are closely associated with the digestive vacuole of the parasite and appear to be composed of neutral lipids. Electron microscopy and isolation of food vacuoles confirmed the size of these particles and their intimate association respectively. Lipid analysis suggests that these neutral lipid bodies are composed of di- and triacylgycerols and may represent storage organelles for lipid intermediates that are generated during digestion of phospholipids in the food vacuole. Mono-, di- and triacylglycerol suspensions promote beta-haematin formation, suggesting that these neutral lipid bodies, or their precursors, may also be involved in haem detoxification. We also characterized other compartments of the infected erythrocyte that were stained less intensely with the Nile Red probe. Both the erythrocyte membrane and the parasite membrane network exhibit red shifts compared with the neutral lipid bodies that are consistent with cholesterol-rich and cholesterol-poor membranes respectively. Ratiometric imaging revealed more subtle variations in the lipid environments within the parasite membrane network.
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Affiliation(s)
- Katherine E Jackson
- Department of Biochemistry, La Trobe University, Melbourne 3086, Victoria, Australia
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41
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Quittnat F, Nishikawa Y, Stedman TT, Voelker DR, Choi JY, Zahn MM, Murphy RC, Barkley RM, Pypaert M, Joiner KA, Coppens I. On the biogenesis of lipid bodies in ancient eukaryotes: synthesis of triacylglycerols by a Toxoplasma DGAT1-related enzyme. Mol Biochem Parasitol 2004; 138:107-22. [PMID: 15500922 DOI: 10.1016/j.molbiopara.2004.08.004] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
In mammalian cells, the main stored neutral lipids are triacylglycerol and cholesteryl esters, which are produced by two related enzymes, acyl-CoA:diacylglycerol acyltransferase (DGAT) and acyl-CoA:cholesterol acyltransferase (ACAT), respectively. Very little is known about the metabolism, intracellular storage and function of neutral lipids in many pathogenic lower eukaryotes. In this paper, we have characterized the activity of an important triacylglycerol synthetic enzyme in the protozoan Toxoplasma gondii. A full-length cDNA and gene encoding a T. gondii DGAT1-related enzyme were identified and designated TgDGAT1. The gene is composed of 15 exons and 14 introns, and encodes a protein with a predicted M(r) 63.5kDa, containing signature motifs characteristic of the DGAT1 family. The native protein migrates at 44kDa under reducing conditions. TgDGAT1 is an integral membrane protein localized to the parasite cortical and perinuclear endoplasmic reticulum, with the C-terminus oriented to the lumen of the organelle. When a Saccharomyces cerevisiae mutant strain lacking neutral lipid production is transformed with TgDGAT1 cDNA, a significant DGAT activity is reconstituted, resulting in triacylglycerol synthesis and biogenesis of cytosolic lipid inclusions, resembling lipid bodies in T. gondii. No production of steryl esters is observed upon TgDGAT1 expression in yeast. In contrast to human DGAT1 lacking fatty acid specificity, TgDGAT1 preferentially incorporates palmitate. Our results indicate that parasitic protozoa are also neutral lipid accumulators and illustrate the first example of the existence of a functional DGAT gene in an ancient eukaryote, demonstrating that diacylglycerol esterification is evolutionarily conserved.
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Affiliation(s)
- Friederike Quittnat
- Department of Internal Medicine, Yale University School of Medicine, 808 LCI, 333 Cedar Street, P.O. Box 208022, New Haven, CT 06520, USA
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42
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Palacpac NMQ, Hiramine Y, Seto S, Hiramatsu R, Horii T, Mitamura T. Evidence that Plasmodium falciparum diacylglycerol acyltransferase is essential for intraerythrocytic proliferation. Biochem Biophys Res Commun 2004; 321:1062-8. [PMID: 15358136 DOI: 10.1016/j.bbrc.2004.07.070] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2004] [Indexed: 10/26/2022]
Abstract
In triacylglycerol (TAG)-accumulating organisms, the physiological roles of diacylglycerol acyltransferase (DGAT), a principal enzyme in the major biosynthetic pathway for TAG, appear to be diverse. Apicomplexan parasite, Plasmodium falciparum, shows unique features in TAG metabolism and trafficking during intraerythrocytic development, and unlike most eukaryotes, only one open reading frame (ORF) encoding a candidate DGAT could be found in its genome. However, whether this candidate ORF encodes P. falciparum DGAT and its physiological relevance have not been assessed. Here, we demonstrate that the ORF is transcribed as a approximately 3.6 kb single mRNA throughout intraerythrocytic development, markedly elevated at trophozoite, schizont, and segmented schizont, and indeed encodes a protein exhibiting DGAT activity. Further, we provide evidence that the parasite in which the ORF was disrupted via double crossover recombination cannot be enriched, implying a fundamental role of PfDGAT in intraerythrocytic proliferation.
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43
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Yang M, Coppens I, Wormsley S, Baevova P, Hoppe HC, Joiner KA. The Plasmodium falciparum Vps4 homolog mediates multivesicular body formation. J Cell Sci 2004; 117:3831-8. [PMID: 15252121 DOI: 10.1242/jcs.01237] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Members of the apicomplexan family of parasites contain morphologically unique secretory organelles termed rhoptries that are essential for host cell invasion. Rhoptries contain internal membranes, and thus resemble multivesicular bodies. To determine whether multivesicular body endosomal intermediates are formed in Apicomplexa, we used the Plasmodium falciparum homolog of the class E gene, Vps4, as a probe. Endogenous P. falciparum Vps4 (PfVps4) localized to the cytoplasm of P. falciparum trophozoites, and transgenic PfVps4 localized to the cytosol in P. falciparum, in the related parasite Toxoplasma gondii and in COS cells. When mutated to block ATP hydrolysis, transiently expressed PfVps4 localized instead to large vesicular structures in P. falciparum. The same construct, and another mutant blocked in ATP binding, generated large cholesterol-enriched multivesicular bodies in both COS cells and T. gondii. Mutant PfVps4 structures in T. gondii co-localized with markers for early endosomes. These results demonstrate a conservation of Vps4 function across wide phylogenetic boundaries, and indicate that endosomal multivesicular bodies form in both P. falciparum and T. gondii.
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Affiliation(s)
- Mei Yang
- Yale University School of Medicine, Department of Medicine, Section of Infectious Disease, 333 Cedar Street, PO Box 208022, New Haven, CT 06520-8022, USA
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