1
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Voss TS, Brancucci NM. Regulation of sexual commitment in malaria parasites - a complex affair. Curr Opin Microbiol 2024; 79:102469. [PMID: 38574448 DOI: 10.1016/j.mib.2024.102469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 03/13/2024] [Accepted: 03/15/2024] [Indexed: 04/06/2024]
Abstract
Malaria blood stage parasites commit to either one of two distinct cellular fates while developing within erythrocytes of their mammalian host: they either undergo another round of asexual replication or they differentiate into nonreplicative transmissible gametocytes. Depending on the state of infection, either path may support or impair the ultimate goal of human-to-human transmission via the mosquito vector. Malaria parasites therefore evolved strategies to control investments into asexual proliferation versus gametocyte formation. Recent work provided fascinating molecular insight into shared and unique mechanisms underlying the control and environmental modulation of sexual commitment in the two most widely studied malaria parasite species, Plasmodium falciparum and P. berghei. With this review, we aim at placing these findings into a comparative mechanistic context.
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Affiliation(s)
- Till S Voss
- Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, 4123 Allschwil, Switzerland; University of Basel, 4001 Basel, Switzerland.
| | - Nicolas Mb Brancucci
- Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, 4123 Allschwil, Switzerland; University of Basel, 4001 Basel, Switzerland.
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2
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Jain A, Sharma R, Gautam L, Shrivastava P, Singh KK, Vyas SP. Biomolecular interactions between Plasmodium and human host: A basis of targeted antimalarial therapy. ANNALES PHARMACEUTIQUES FRANÇAISES 2024; 82:401-419. [PMID: 38519002 DOI: 10.1016/j.pharma.2024.03.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2023] [Revised: 03/12/2024] [Accepted: 03/18/2024] [Indexed: 03/24/2024]
Abstract
Malaria is one of the serious health concerns worldwide as it remains a clinical challenge due to the complex life cycle of the malaria parasite and the morphological changes it undergoes during infection. The malaria parasite multiplies rapidly and spreads in the population by changing its alternative hosts. These various morphological stages of the parasite in the human host cause clinical symptoms (anemia, fever, and coma). These symptoms arise due to the preprogrammed biology of the parasite in response to the human pathophysiological response. Thus, complete elimination becomes one of the major health challenges. Although malaria vaccine(s) are available in the market, they still contain to cause high morbidity and mortality. Therefore, an approach for eradication is needed through the exploration of novel molecular targets by tracking the epidemiological changes the parasite adopts. This review focuses on the various novel molecular targets.
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Affiliation(s)
- Anamika Jain
- Drug Delivery and Research Laboratory, Department of Pharmaceutical Sciences, Dr. Harisingh Gour University, Sagar, M.P., 470003, India
| | - Rajeev Sharma
- Amity Institute of Pharmacy, Amity University Madhya Pradesh, Gwalior, M.P., 474005, India.
| | - Laxmikant Gautam
- Babulal Tarabai Institute of Pharmaceutical Science, Sagar, M.P., 470228, India
| | - Priya Shrivastava
- Drug Delivery and Research Laboratory, Department of Pharmaceutical Sciences, Dr. Harisingh Gour University, Sagar, M.P., 470003, India
| | - Kamalinder K Singh
- School of Pharmacy and Biomedical Sciences, Faculty of Clinical and Biomedical Sciences, University of Central Lancashire, Preston PR1 2HE, United Kingdom
| | - Suresh P Vyas
- Drug Delivery and Research Laboratory, Department of Pharmaceutical Sciences, Dr. Harisingh Gour University, Sagar, M.P., 470003, India.
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3
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Zhang X, Sicalo Gianechini L, Li K, Kaplan RM, Witola WH. Broad-Spectrum Inhibitors for Conserved Unique Phosphoethanolamine Methyltransferases in Parasitic Nematodes Possess Anthelmintic Efficacy. Antimicrob Agents Chemother 2023; 67:e0000823. [PMID: 37212658 PMCID: PMC10269165 DOI: 10.1128/aac.00008-23] [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: 01/03/2023] [Accepted: 04/20/2023] [Indexed: 05/23/2023] Open
Abstract
In humans, nematode infections are prevalent in developing countries, causing long-term ill health, particularly in children. Worldwide, nematode infections are prevalent in livestock and pets, affecting productivity and health. Anthelmintic drugs are the primary means of controlling nematodes, but there is now high prevalence of anthelmintic resistance, requiring urgent identification of new molecular targets for anthelmintics with novel mechanisms of action. Here, we identified orthologous genes for phosphoethanolamine methyltransferases (PMTs) in nematodes within the families Trichostrongylidae, Dictyocaulidae, Chabertiidae, Ancylostomatoidea, and Ascarididae. We characterized these putative PMTs and found that they possess bona fide PMT catalytic activities. By complementing a mutant yeast strain lacking the ability to synthesize phosphatidylcholine, the PMTs were validated to catalyze the biosynthesis of phosphatidylcholine. Using an in vitro phosphoethanolamine methyltransferase assay with PMTs as enzymes, we identified compounds with cross-inhibitory effects against the PMTs. Corroboratively, treatment of PMT-complemented yeast with the PMT inhibitors blocked growth of the yeast, underscoring the essential role of the PMTs in phosphatidylcholine synthesis. Fifteen of the inhibitors with the highest activity against complemented yeast were tested against Haemonchus contortus using larval development and motility assays. Among them, four were found to possess potent anthelmintic activity against both multiple drug-resistant and susceptible isolates of H. contortus, with IC50 values (95% confidence interval) of 4.30 μM (2.15-8.28), 4.46 μM (3.22-6.16), 28.7 μM (17.3-49.5), and 0.65 μM (0.21-1.88). Taken together, we have validated a molecular target conserved in a broad range of nematodes and identified its inhibitors that possess potent in vitro anthelmintic activity.
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Affiliation(s)
- Xuejin Zhang
- Department of Pathobiology, College of Veterinary Medicine, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
| | | | - Kun Li
- Department of Pathobiology, College of Veterinary Medicine, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
- Institute of Traditional Chinese Veterinary Medicine, MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Ray M. Kaplan
- Department of Infectious Diseases, University of Georgia, Athens, Georgia, USA
- Pathobiology Department, School of Veterinary Medicine, St. George’s University, Grenada, West Indies
| | - William H. Witola
- Department of Pathobiology, College of Veterinary Medicine, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
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4
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Schneider V, Visone J, Harris C, Florini F, Hadjimichael E, Zhang X, Gross M, Rhee K, Ben Mamoun C, Kafsack B, Deitsch K. The human malaria parasite Plasmodium falciparum can sense environmental changes and respond by antigenic switching. Proc Natl Acad Sci U S A 2023; 120:e2302152120. [PMID: 37068249 PMCID: PMC10151525 DOI: 10.1073/pnas.2302152120] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Accepted: 03/20/2023] [Indexed: 04/19/2023] Open
Abstract
The primary antigenic and virulence determinant of the human malaria parasite Plasmodium falciparum is a variant surface protein called PfEMP1. Different forms of PfEMP1 are encoded by a multicopy gene family called var, and switching between active genes enables the parasites to evade the antibody response of their human hosts. var gene switching is key for the maintenance of chronic infections; however, what controls switching is unknown, although it has been suggested to occur at a constant frequency with little or no environmental influence. var gene transcription is controlled epigenetically through the activity of histone methyltransferases (HMTs). Studies in model systems have shown that metabolism and epigenetic control of gene expression are linked through the availability of intracellular S-adenosylmethionine (SAM), the principal methyl donor in biological methylation modifications, which can fluctuate based on nutrient availability. To determine whether environmental conditions and changes in metabolism can influence var gene expression, P. falciparum was cultured in media with altered concentrations of nutrients involved in SAM metabolism. We found that conditions that influence lipid metabolism induce var gene switching, indicating that parasites can respond to changes in their environment by altering var gene expression patterns. Genetic modifications that directly modified expression of the enzymes that control SAM levels similarly led to profound changes in var gene expression, confirming that changes in SAM availability modulate var gene switching. These observations directly challenge the paradigm that antigenic variation in P. falciparum follows an intrinsic, programed switching rate, which operates independently of any external stimuli.
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Affiliation(s)
- Victoria M. Schneider
- Department of Microbiology and Immunology, Weill Cornell Medicine, Cornell University, Ithaca, NY14853
- Laboratory of Chemical Biology and Microbial Pathogenesis, Rockefeller University, New York, NY 10065
| | - Joseph E. Visone
- Department of Microbiology and Immunology, Weill Cornell Medicine, Cornell University, Ithaca, NY14853
| | - Chantal T. Harris
- Department of Microbiology and Immunology, Weill Cornell Medicine, Cornell University, Ithaca, NY14853
| | - Francesca Florini
- Department of Microbiology and Immunology, Weill Cornell Medicine, Cornell University, Ithaca, NY14853
| | - Evi Hadjimichael
- Department of Microbiology and Immunology, Weill Cornell Medicine, Cornell University, Ithaca, NY14853
| | - Xu Zhang
- Department of Microbiology and Immunology, Weill Cornell Medicine, Cornell University, Ithaca, NY14853
| | - Mackensie R. Gross
- Department of Microbiology and Immunology, Weill Cornell Medicine, Cornell University, Ithaca, NY14853
| | - Kyu Y. Rhee
- Department of Microbiology and Immunology, Weill Cornell Medicine, Cornell University, Ithaca, NY14853
- Division of Infectious Diseases, Department of Medicine, Weill Cornell Medicine, Cornell University, Ithaca, NY14853
| | - Choukri Ben Mamoun
- Section of Infectious Disease, Department of Microbial Pathogenesis, Yale School of Medicine, Yale University New Haven, CT 06510
| | - Björn F. C. Kafsack
- Department of Microbiology and Immunology, Weill Cornell Medicine, Cornell University, Ithaca, NY14853
| | - Kirk W. Deitsch
- Department of Microbiology and Immunology, Weill Cornell Medicine, Cornell University, Ithaca, NY14853
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5
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Sheokand PK, Yamaryo-Botté Y, Narwal M, Arnold CS, Thakur V, Islam MM, Banday MM, Asad M, Botté CY, Mohmmed A. A Plasmodium falciparum lysophospholipase regulates host fatty acid flux via parasite lipid storage to enable controlled asexual schizogony. Cell Rep 2023; 42:112251. [PMID: 37015228 DOI: 10.1016/j.celrep.2023.112251] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 11/04/2022] [Accepted: 02/24/2023] [Indexed: 04/05/2023] Open
Abstract
Phospholipid metabolism is crucial for membrane biogenesis and homeostasis of Plasmodium falciparum. To generate such phospholipids, the parasite extensively scavenges, recycles, and reassembles host lipids. P. falciparum possesses an unusually large number of lysophospholipases, whose roles and importance remain to be elucidated. Here, we functionally characterize one P. falciparum lysophospholipase, PfLPL3, to reveal its key role in parasite propagation during asexual blood stages. PfLPL3 displays a dynamic localization throughout asexual stages, mainly localizing in the host-parasite interface. Inducible knockdown of PfLPL3 disrupts parasite development from trophozoites to schizont, inducing a drastic reduction in merozoite progenies. Detailed lipidomic analyses show that PfLPL3 generates fatty acids from scavenged host lipids to generate neutral lipids. These are then timely mobilized to allow schizogony and merozoite formation. We then identify inhibitors of PfLPL3 from Medicine for Malaria Venture (MMV) with potent antimalarial activity, which could also serve as pertinent chemical tools to study parasite lipid synthesis.
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Affiliation(s)
- Pradeep Kumar Sheokand
- 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
| | - Monika Narwal
- International Centre for Genetic Engineering and Biotechnology, New Delhi 110 067, India
| | - Christophe-Sébastien Arnold
- ApicoLipid Team, Institute for Advanced Biosciences, CNRS UMR5309, Université Grenoble Alpes, INSERM U1209, Grenoble, France
| | - Vandana Thakur
- International Centre for Genetic Engineering and Biotechnology, New Delhi 110 067, India
| | - Md Muzahidul Islam
- International Centre for Genetic Engineering and Biotechnology, New Delhi 110 067, India
| | - Mudassir M Banday
- International Centre for Genetic Engineering and Biotechnology, New Delhi 110 067, India
| | - Mohd Asad
- 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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Kwarteng DO, Gangoda M, Kooijman EE. The effect of methylated phosphatidylethanolamine derivatives on the ionization properties of signaling phosphatidic acid. Biophys Chem 2023; 296:107005. [PMID: 36934676 DOI: 10.1016/j.bpc.2023.107005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Accepted: 03/07/2023] [Indexed: 03/16/2023]
Abstract
Phosphatidylethanolamine (PE) and Phosphatidylcholine (PC) are the most abundant glycerophospholipids in eukaryotic membranes. The differences in the physicochemical properties of their headgroups have contrasting modulatory effects on their interaction with intracellular macromolecules. As such, their overall impact on membrane structure and function differs significantly. Enzymatic methylation of PE's amine headgroup produces two methylated derivatives namely monomethyl PE (MMPE) and dimethyl PE (DMPE) which have physicochemical properties that generally range between that of PE and PC. Additionally, their influence on membrane properties differs from both PE and PC. Although variations in headgroup methylation have been reported to affect signaling pathways, the direct influence that these differences exert on the ionization properties of signaling phospholipids have not been investigated. Here, we briefly review membrane function and structure that are mediated by the differences in headgroup methylation between PE, MMPE, DMPE and PC. In addition, using 31P MAS NMR, we investigate the effect of these four phospholipids on the ionization properties of the ubiquitous signaling anionic lipid phosphatidic acid (PA). Our results show that PA's ionization properties are differentially affected by changes in phospholipid headgroup methylation. This could have important implications for PA-protein binding and hence physiological functions in cells where signaling events lead to changes in abundance of methylated PE derivatives in the membrane.
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Affiliation(s)
- Desmond Owusu Kwarteng
- Department of Biological Sciences, Kent State University, P.O. Box 5190, Kent, OH 44242, USA.
| | - Mahinda Gangoda
- Department of Chemistry & Biochemistry, Kent State University, P.O. Box 5190, Kent, OH 44242, USA
| | - Edgar E Kooijman
- Department of Biological Sciences, Kent State University, P.O. Box 5190, Kent, OH 44242, USA.
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7
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Cruz Camacho A, Kiper E, Oren S, Zaharoni N, Nir N, Soffer N, Noy Y, Ben David B, Rivkin A, Rotkopf R, Michael D, Carvalho TG, Regev-Rudzki N. High-throughput analysis of the transcriptional patterns of sexual genes in malaria. Parasit Vectors 2023; 16:14. [PMID: 36639683 PMCID: PMC9838061 DOI: 10.1186/s13071-022-05624-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Accepted: 12/17/2022] [Indexed: 01/15/2023] Open
Abstract
BACKGROUND Plasmodium falciparum (Pf) is the leading protozoan causing malaria, the most devastating parasitic disease. To ensure transmission, a small subset of Pf parasites differentiate into the sexual forms (gametocytes). Since the abundance of these essential parasitic forms is extremely low within the human host, little is currently known about the molecular regulation of their sexual differentiation, highlighting the need to develop tools to investigate Pf gene expression during this fundamental mechanism. METHODS We developed a high-throughput quantitative Reverse-Transcription PCR (RT-qPCR) platform to robustly monitor Pf transcriptional patterns, in particular, systematically profiling the transcriptional pattern of a large panel of gametocyte-related genes (GRG). Initially, we evaluated the technical performance of the systematic RT-qPCR platform to ensure it complies with the accepted quality standards for: (i) RNA extraction, (ii) cDNA synthesis and (iii) evaluation of gene expression through RT-qPCR. We then used this approach to monitor alterations in gene expression of a panel of GRG upon treatment with gametocytogenesis regulators. RESULTS We thoroughly elucidated GRG expression profiles under treatment with the antimalarial drug dihydroartemisinin (DHA) or the metabolite choline over the course of a Pf blood cycle (48 h). We demonstrate that both significantly alter the expression pattern of PfAP2-G, the gametocytogenesis master regulator. However, they also markedly modify the developmental rate of the parasites and thus might bias the mRNA expression. Additionally, we screened the effect of the metabolites lactate and kynurenic acid, abundant in severe malaria, as potential regulators of gametocytogenesis. CONCLUSIONS Our data demonstrate that the high-throughput RT-qPCR method enables studying the immediate transcriptional response initiating gametocytogenesis of the parasites from a very low volume of malaria-infected RBC samples. The obtained data expand the current knowledge of the initial alterations in mRNA profiles of GRG upon treatment with reported regulators. In addition, using this method emphasizes that asexual parasite stage composition is a crucial element that must be considered when interpreting changes in GRG expression by RT-qPCR, specifically when screening for novel compounds that could regulate Pf sexual differentiation.
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Affiliation(s)
- Abel Cruz Camacho
- grid.13992.300000 0004 0604 7563Faculty of Biochemistry, Department of Biomolecular Sciences, Weizmann Institute of Science, 7610001 Rehovot, Israel
| | - Edo Kiper
- grid.13992.300000 0004 0604 7563Faculty of Biochemistry, Department of Biomolecular Sciences, Weizmann Institute of Science, 7610001 Rehovot, Israel
| | - Sonia Oren
- grid.13992.300000 0004 0604 7563Faculty of Biochemistry, Department of Biomolecular Sciences, Weizmann Institute of Science, 7610001 Rehovot, Israel
| | - Nir Zaharoni
- grid.13992.300000 0004 0604 7563Faculty of Biochemistry, Department of Biomolecular Sciences, Weizmann Institute of Science, 7610001 Rehovot, Israel
| | - Netta Nir
- grid.13992.300000 0004 0604 7563Faculty of Biochemistry, Department of Biomolecular Sciences, Weizmann Institute of Science, 7610001 Rehovot, Israel
| | - Noam Soffer
- grid.13992.300000 0004 0604 7563Faculty of Biochemistry, Department of Biomolecular Sciences, Weizmann Institute of Science, 7610001 Rehovot, Israel
| | - Yael Noy
- grid.13992.300000 0004 0604 7563Faculty of Biochemistry, Department of Biomolecular Sciences, Weizmann Institute of Science, 7610001 Rehovot, Israel
| | - Bar Ben David
- grid.13992.300000 0004 0604 7563Faculty of Biochemistry, Department of Biomolecular Sciences, Weizmann Institute of Science, 7610001 Rehovot, Israel
| | - Anna Rivkin
- grid.13992.300000 0004 0604 7563Faculty of Biochemistry, Department of Biomolecular Sciences, Weizmann Institute of Science, 7610001 Rehovot, Israel
| | - Ron Rotkopf
- grid.13992.300000 0004 0604 7563Department of Life Sciences Core Facilities, Weizmann Institute of Science, 7610001 Rehovot, Israel
| | - Dan Michael
- grid.13992.300000 0004 0604 7563Feinberg Graduate School, Weizmann Institute of Science, 7610001 Rehovot, Israel
| | - Teresa G. Carvalho
- grid.1018.80000 0001 2342 0938Department of Microbiology, Anatomy, Physiology and Pharmacology, La Trobe University, Melbourne, VIC 3086 Australia
| | - Neta Regev-Rudzki
- grid.13992.300000 0004 0604 7563Faculty of Biochemistry, Department of Biomolecular Sciences, Weizmann Institute of Science, 7610001 Rehovot, Israel
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8
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El Rhabori S, El Aissouq A, Chtita S, Khalil F. QSAR, molecular docking and ADMET studies of quinoline, isoquinoline and quinazoline derivatives against Plasmodium falciparum malaria. Struct Chem 2022. [DOI: 10.1007/s11224-022-01988-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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9
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van der Watt ME, Reader J, Birkholtz LM. Adapt or Die: Targeting Unique Transmission-Stage Biology for Malaria Elimination. Front Cell Infect Microbiol 2022; 12:901971. [PMID: 35755845 PMCID: PMC9218253 DOI: 10.3389/fcimb.2022.901971] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 05/06/2022] [Indexed: 12/25/2022] Open
Abstract
Plasmodium parasites have a complex life cycle that includes development in the human host as well as the Anopheles vector. Successful transmission of the parasite between its host and vector therefore requires the parasite to balance its investments in asexual replication and sexual reproduction, varying the frequency of sexual commitment to persist within the human host and generate future opportunities for transmission. The transmission window is extended further by the ability of stage V gametocytes to circulate in peripheral blood for weeks, whereas immature stage I to IV gametocytes sequester in the bone marrow and spleen until final maturation. Due to the low gametocyte numbers in blood circulation and with the ease of targeting such life cycle bottlenecks, transmission represents an efficient target for therapeutic intervention. The biological process of Plasmodium transmission is a multistage, multifaceted process and the past decade has seen a much deeper understanding of the molecular mechanisms and regulators involved. Clearly, specific and divergent processes are used during transmission compared to asexual proliferation, which both poses challenges but also opportunities for discovery of transmission-blocking antimalarials. This review therefore presents an update of our molecular understanding of gametocyte and gamete biology as well as the status of transmission-blocking activities of current antimalarials and lead development compounds. By defining the biological components associated with transmission, considerations for the development of new transmission-blocking drugs to target such untapped but unique biology is suggested as an important, main driver for transmission-blocking drug discovery.
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Affiliation(s)
- Mariëtte E van der Watt
- Institute for Sustainable Malaria Control, School of Health Systems and Public Health, University of Pretoria, Pretoria, South Africa
| | - Janette Reader
- Institute for Sustainable Malaria Control, School of Health Systems and Public Health, University of Pretoria, Pretoria, South Africa.,Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa
| | - Lyn-Marié Birkholtz
- Institute for Sustainable Malaria Control, School of Health Systems and Public Health, University of Pretoria, Pretoria, South Africa.,Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa
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10
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Anwar O, Islam M, Thakur V, Kaur I, Mohmmed A. Defining ER-mitochondria contact dynamics in Plasmodium falciparum by targeting component of phospholipid synthesis pathway, Phosphatidylserine synthase (PfPSS). Mitochondrion 2022; 65:124-138. [PMID: 35623558 DOI: 10.1016/j.mito.2022.05.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 05/14/2022] [Accepted: 05/22/2022] [Indexed: 10/18/2022]
Abstract
The malaria parasite completes the asexual cycle inside the host erythrocyte, which requires extensive membrane biogenesis for its development and multiplication. Metabolic pathways for the synthesis of membrane phospholipids (PL), including phosphatidylcholine (PC), phosphatidylethanolamine (PE) and phosphatidylserine (PS), are crucial for parasite survival. Here, we have studied the P. falciparum enzyme responsible for PS synthesis, Phosphatidylserine synthase (PfPSS), GFP targeting approach confirmed it to be localized in the parasite ER as well as in ER-protrusions. Detailed high resolution microscopy, using these transgenic parasites expressing PfPSS-GFP, redefined the dynamics of ER during the intraerythrocytic life cycle and its association with the mitochondria. We report for the first time presence of ER-mitochondria contact (ERMC) in Plasmodium; ERMC is formed by PfPSS containing ER-protrusions, which associate with the mitochondria surface throughout the parasite growth cycle. Further, ERMC is found to be stable and refractory to ER and mitochondrial stresses, suggesting that it is formed through strong tethering complexes. PfPSS was found to interact with other major key enzyme involved in PL synthesis, choline/Etn-phosphotransferase (CEPT), which suggest that ER is the major site for PL biosynthesis. Overall, this study defines the morphological organisation of ERMC which mediates PL synthesis/transport in the Plasmodium.
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Affiliation(s)
- Omair Anwar
- International Centre for Genetic Engineering and Biotechnology, New Delhi 110 067, India
| | - Muzahidul Islam
- 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
| | - Inderjeet Kaur
- International Centre for Genetic Engineering and Biotechnology, New Delhi 110 067, India
| | - Asif Mohmmed
- International Centre for Genetic Engineering and Biotechnology, New Delhi 110 067, India.
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11
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Maurya R, Tripathi A, Kumar M, Antil N, Yamaryo‐Botté Y, Kumar P, Bansal P, Doerig C, Botté CY, Prasad TSK, Sharma P. PI4-kinase and PfCDPK7 signaling regulate phospholipid biosynthesis in Plasmodium falciparum. EMBO Rep 2022; 23:e54022. [PMID: 34866326 PMCID: PMC8811644 DOI: 10.15252/embr.202154022] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 10/30/2021] [Accepted: 11/11/2021] [Indexed: 02/05/2023] Open
Abstract
PfCDPK7 is an atypical member of the calcium-dependent protein kinase (CDPK) family and is crucial for the development of Plasmodium falciparum. However, the mechanisms whereby PfCDPK7 regulates parasite development remain unknown. Here, we perform quantitative phosphoproteomics and phospholipid analysis and find that PfCDPK7 promotes phosphatidylcholine (PC) synthesis by regulating two key enzymes involved in PC synthesis, phosphoethanolamine-N-methyltransferase (PMT) and ethanolamine kinase (EK). In the absence of PfCDPK7, both enzymes are hypophosphorylated and PMT is degraded. We further find that PfCDPK7 interacts with 4'-phosphorylated phosphoinositides (PIPs) generated by PI4-kinase. Inhibition of PI4K activity disrupts the vesicular localization PfCDPK7. P. falciparum PI4-kinase, PfPI4K is a prominent drug target and one of its inhibitors, MMV39048, has reached Phase I clinical trials. Using this inhibitor, we demonstrate that PfPI4K controls phospholipid biosynthesis and may act in part by regulating PfCDPK7 localization and activity. These studies not only unravel a signaling pathway involving PfPI4K/4'-PIPs and PfCDPK7 but also provide novel insights into the mechanism of action of a promising series of candidate anti-malarial drugs.
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Affiliation(s)
- Ranjana Maurya
- Eukaryotic Gene Expression laboratoryNational Institute of ImmunologyNew DelhiIndia
| | - Anuj Tripathi
- Eukaryotic Gene Expression laboratoryNational Institute of ImmunologyNew DelhiIndia
| | - Manish Kumar
- Eukaryotic Gene Expression laboratoryNational Institute of ImmunologyNew DelhiIndia
- Institute of BioinformaticsInternational Tech ParkBangaloreIndia
- Manipal Academy of Higher EducationManipalIndia
| | - Neelam Antil
- Institute of BioinformaticsInternational Tech ParkBangaloreIndia
- ApicoLipid TeamInstitute of Advanced BiosciencesCNRS UMR5309Université Grenoble AlpesINSERM U1209GrenobleFrance
- Amrita School of BiotechnologyAmrita Vishwa VidyapeethamKollamIndia
| | - Yoshiki Yamaryo‐Botté
- Center for Systems Biology and Molecular MedicineYenepoya Research CentreYenepoya (Deemed to be University)MangaloreIndia
| | - Praveen Kumar
- Eukaryotic Gene Expression laboratoryNational Institute of ImmunologyNew DelhiIndia
| | - Priyanka Bansal
- Eukaryotic Gene Expression laboratoryNational Institute of ImmunologyNew DelhiIndia
| | - Christian Doerig
- NIMHANS IOB Proteomics and Bioinformatics LaboratoryNeurobiology Research CentreNational Institute of Mental Health and Neuro SciencesBangaloreIndia
| | - Cyrille Y Botté
- Center for Systems Biology and Molecular MedicineYenepoya Research CentreYenepoya (Deemed to be University)MangaloreIndia
| | - T S Keshava Prasad
- Institute of BioinformaticsInternational Tech ParkBangaloreIndia
- Amrita School of BiotechnologyAmrita Vishwa VidyapeethamKollamIndia
- School of Health and Biomedical SciencesRMIT UniversityBundooraVic.Australia
| | - Pushkar Sharma
- Eukaryotic Gene Expression laboratoryNational Institute of ImmunologyNew DelhiIndia
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12
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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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13
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Usui M, Williamson KC. Stressed Out About Plasmodium falciparum Gametocytogenesis. Front Cell Infect Microbiol 2021; 11:790067. [PMID: 34926328 PMCID: PMC8674873 DOI: 10.3389/fcimb.2021.790067] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Accepted: 11/08/2021] [Indexed: 11/21/2022] Open
Abstract
Blocking malaria transmission is critical to malaria control programs but remains a major challenge especially in endemic regions with high levels of asymptomatic infections. New strategies targeting the transmissible sexual stages of the parasite, called gametocytes, are needed. This review focuses on P. falciparum gametocytogenesis in vivo and in vitro. Highlighting advances made elucidating genes required for gametocyte production and identifying key questions that remain unanswered such as the factors and regulatory mechanisms that contribute to gametocyte induction, and the mechanism of sequestration. Tools available to begin to address these issues are also described to facilitate advances in our understanding of this important stage of the life cycle.
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Affiliation(s)
- Miho Usui
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - Kim C Williamson
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
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14
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Cobbold SA, V Tutor M, Frasse P, McHugh E, Karnthaler M, Creek DJ, Odom John A, Tilley L, Ralph SA, McConville MJ. Non-canonical metabolic pathways in the malaria parasite detected by isotope-tracing metabolomics. Mol Syst Biol 2021; 17:e10023. [PMID: 33821563 PMCID: PMC8022201 DOI: 10.15252/msb.202010023] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 02/02/2021] [Accepted: 02/04/2021] [Indexed: 12/26/2022] Open
Abstract
The malaria parasite, Plasmodium falciparum, proliferates rapidly in human erythrocytes by actively scavenging multiple carbon sources and essential nutrients from its host cell. However, a global overview of the metabolic capacity of intraerythrocytic stages is missing. Using multiplex 13 C-labelling coupled with untargeted mass spectrometry and unsupervised isotopologue grouping, we have generated a draft metabolome of P. falciparum and its host erythrocyte consisting of 911 and 577 metabolites, respectively, corresponding to 41% of metabolites and over 70% of the metabolic reaction predicted from the parasite genome. An additional 89 metabolites and 92 reactions were identified that were not predicted from genomic reconstructions, with the largest group being associated with metabolite damage-repair systems. Validation of the draft metabolome revealed four previously uncharacterised enzymes which impact isoprenoid biosynthesis, lipid homeostasis and mitochondrial metabolism and are necessary for parasite development and proliferation. This study defines the metabolic fate of multiple carbon sources in P. falciparum, and highlights the activity of metabolite repair pathways in these rapidly growing parasite stages, opening new avenues for drug discovery.
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Affiliation(s)
- Simon A Cobbold
- Department of Biochemistry and Molecular BiologyBio21 Institute of Molecular Science and BiotechnologyUniversity of MelbourneParkvilleVic.Australia
| | - Madel V Tutor
- Department of Biochemistry and Molecular BiologyBio21 Institute of Molecular Science and BiotechnologyUniversity of MelbourneParkvilleVic.Australia
| | - Philip Frasse
- Department of MedicineWashington University School of MedicineSt. LouisMOUSA
| | - Emma McHugh
- Department of Biochemistry and Molecular BiologyBio21 Institute of Molecular Science and BiotechnologyUniversity of MelbourneParkvilleVic.Australia
| | - Markus Karnthaler
- Department of Biochemistry and Molecular BiologyBio21 Institute of Molecular Science and BiotechnologyUniversity of MelbourneParkvilleVic.Australia
| | - Darren J Creek
- Monash Institute of Pharmaceutical SciencesMonash UniversityParkvilleVic.Australia
| | - Audrey Odom John
- The Children’s Hospital of PhiladelphiaUniversity of PennsylvaniaPhiladelphiaPAUSA
| | - Leann Tilley
- Department of Biochemistry and Molecular BiologyBio21 Institute of Molecular Science and BiotechnologyUniversity of MelbourneParkvilleVic.Australia
| | - Stuart A Ralph
- Department of Biochemistry and Molecular BiologyBio21 Institute of Molecular Science and BiotechnologyUniversity of MelbourneParkvilleVic.Australia
| | - Malcolm J McConville
- Department of Biochemistry and Molecular BiologyBio21 Institute of Molecular Science and BiotechnologyUniversity of MelbourneParkvilleVic.Australia
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15
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Fabbri C, Trindade AO, Andrade FS, Souza MFD, Ríos-Velásquez CM, Lacerda MVGD, Monteiro WM, Costa FTM, Amino R, Lopes SCP. Transmission-blocking compound candidates against Plasmodium vivax using P. berghei as an initial screening. Mem Inst Oswaldo Cruz 2021; 116:e200513. [PMID: 33566952 PMCID: PMC7874845 DOI: 10.1590/0074-02760200513] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Accepted: 01/04/2021] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Different strategies for improvement of malaria control and elimination are based on the blockage of malaria parasite transmission to the mosquito vector. These strategies include the drugs that target the plasmodial sexual stages in humans and the early developmental stages inside mosquitoes. OBJECTIVES Here we tested Malaria Box compounds in order to evaluate their activity against male and female gametocytes in Plasmodium berghei, mosquito infection in P. vivax and ookinete formation in both species. METHODS/FINDINGS The membrane feeding assay and the development of ookinetes by a 24 h ex vivo culture and the ookinete yield per 1000 erythrocytes were used to test transmission-blocking potential of the Malaria Box compounds in P. vivax. For P. berghei we used flow cytometry to evaluate male and female gametocyte time course and fluorescence microscopy to check the ookinete development. The two species used in this study showed similar results concerning the compounds’ activity against gametocytes and ookinetes, which were different from those in P. falciparum. In addition, from the eight Malaria Box compounds tested in both species, compounds MMV665830, MMV665878 and MMV665941 were selected as a hit compounds due the high inhibition observed. CONCLUSION Our results showed that P. berghei is suitable as an initial screening system to test compounds against P. vivax.
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Affiliation(s)
- Camila Fabbri
- Fundação de Medicina Tropical Dr Heitor Vieira Dourado, Instituto de Pesquisa Clínica Carlos Borborema, Manaus, AM, Brasil.,Universidade do Estado do Amazonas, Programa de Pós-Graduação em Medicina Tropical, Manaus, AM, Brasil.,Centro Universitário Fametro, Manaus, AM, Brasil
| | - Alexandre Oliveira Trindade
- Fundação de Medicina Tropical Dr Heitor Vieira Dourado, Instituto de Pesquisa Clínica Carlos Borborema, Manaus, AM, Brasil
| | - Francy's Sayara Andrade
- Fundação de Medicina Tropical Dr Heitor Vieira Dourado, Instituto de Pesquisa Clínica Carlos Borborema, Manaus, AM, Brasil.,Universidade do Estado do Amazonas, Programa de Pós-Graduação em Medicina Tropical, Manaus, AM, Brasil
| | - Macejane Ferreira de Souza
- Fundação de Medicina Tropical Dr Heitor Vieira Dourado, Instituto de Pesquisa Clínica Carlos Borborema, Manaus, AM, Brasil.,Universidade do Estado do Amazonas, Programa de Pós-Graduação em Medicina Tropical, Manaus, AM, Brasil
| | | | - Marcus Vinicius Guimarães de Lacerda
- Fundação de Medicina Tropical Dr Heitor Vieira Dourado, Instituto de Pesquisa Clínica Carlos Borborema, Manaus, AM, Brasil.,Universidade do Estado do Amazonas, Programa de Pós-Graduação em Medicina Tropical, Manaus, AM, Brasil.,Fundação Oswaldo Cruz-Fiocruz, Instituto Leônidas e Maria Deane, Manaus, AM, Brasil
| | - Wuelton Marcelo Monteiro
- Fundação de Medicina Tropical Dr Heitor Vieira Dourado, Instituto de Pesquisa Clínica Carlos Borborema, Manaus, AM, Brasil.,Universidade do Estado do Amazonas, Programa de Pós-Graduação em Medicina Tropical, Manaus, AM, Brasil
| | - Fabio Trindade Maranhão Costa
- Fundação Oswaldo Cruz-Fiocruz, Instituto Leônidas e Maria Deane, Manaus, AM, Brasil.,Universidade Estadual de Campinas, Campinas, SP, Brasil
| | - Rogerio Amino
- Institut Pasteur, Unit of Malaria Infection and Immunity, Department of Parasites and Insect Vectors, Paris, Île-de-France, France
| | - Stefanie Costa Pinto Lopes
- Fundação de Medicina Tropical Dr Heitor Vieira Dourado, Instituto de Pesquisa Clínica Carlos Borborema, Manaus, AM, Brasil.,Universidade do Estado do Amazonas, Programa de Pós-Graduação em Medicina Tropical, Manaus, AM, Brasil.,Fundação Oswaldo Cruz-Fiocruz, Instituto Leônidas e Maria Deane, Manaus, AM, Brasil
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16
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Nakamura Y. Headgroup biosynthesis of phosphatidylcholine and phosphatidylethanolamine in seed plants. Prog Lipid Res 2021; 82:101091. [PMID: 33503494 DOI: 10.1016/j.plipres.2021.101091] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2020] [Revised: 01/12/2021] [Accepted: 01/17/2021] [Indexed: 12/23/2022]
Abstract
Phospholipid biosynthesis is crucial for plant growth and development. It involves attachment of fatty acids to a phospho-diacylglycerol backbone and modification of the phospho-group into an amino alcohol. The biochemistry and molecular biology of the former has been well established, but a number of enzymes responsible for the latter have only recently been cloned and functionally characterized in Arabidopsis and some other model plant species. The metabolism involving the polar head groups of phospholipids established by past biochemical studies can now be validated by available gene knockout models. Moreover, gene knockout studies have revealed emerging functions of phospholipids in regulating plant growth and development. This review aims to revisit the old questions of polar headgroup biosynthesis of plant phosphatidylcholine and phosphatidylethanolamine by giving an overview of recent advances in the field and beyond.
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Affiliation(s)
- Yuki Nakamura
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan.
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17
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Dousti M, Manzano-Román R, Rashidi S, Barzegar G, Ahmadpour NB, Mohammadi A, Hatam G. A proteomic glimpse into the effect of antimalarial drugs on Plasmodium falciparum proteome towards highlighting possible therapeutic targets. Pathog Dis 2021; 79:ftaa071. [PMID: 33202000 DOI: 10.1093/femspd/ftaa071] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 11/13/2020] [Indexed: 02/07/2023] Open
Abstract
There is no effective vaccine against malaria; therefore, chemotherapy is to date the only choice to fight against this infectious disease. However, there is growing evidences of drug-resistance mechanisms in malaria treatments. Therefore, the identification of new drug targets is an urgent need for the clinical management of the disease. Proteomic approaches offer the chance of determining the effects of antimalarial drugs on the proteome of Plasmodium parasites. Accordingly, we reviewed the effects of antimalarial drugs on the Plasmodium falciparum proteome pointing out the relevance of several proteins as possible drug targets in malaria treatment. In addition, some of the P. falciparum stage-specific altered proteins and parasite-host interactions might play important roles in pathogenicity, survival, invasion and metabolic pathways and thus serve as potential sources of drug targets. In this review, we have identified several proteins, including thioredoxin reductase, helicases, peptidyl-prolyl cis-trans isomerase, endoplasmic reticulum-resident calcium-binding protein, choline/ethanolamine phosphotransferase, purine nucleoside phosphorylase, apical membrane antigen 1, glutamate dehydrogenase, hypoxanthine guanine phosphoribosyl transferase, heat shock protein 70x, knob-associated histidine-rich protein and erythrocyte membrane protein 1, as promising antimalarial drugs targets. Overall, proteomic approaches are able to partially facilitate finding possible drug targets. However, the integration of other 'omics' and specific pharmaceutical techniques with proteomics may increase the therapeutic properties of the critical proteins identified in the P. falciparum proteome.
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Affiliation(s)
- Majid Dousti
- Department of Parasitology and Mycology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Raúl Manzano-Román
- Proteomics Unit, Cancer Research Centre (IBMCC/CSIC/USAL/IBSAL), 37007, Salamanca, Spain
| | - Sajad Rashidi
- Department of Parasitology and Mycology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Gholamreza Barzegar
- Department of Parasitology and Mycology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | | | - Alireza Mohammadi
- Department of Disease Control, Komijan Treatment and Health Network, Arak University of Medical Science, Iran
| | - Gholamreza Hatam
- Basic Sciences in Infectious Diseases Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
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18
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Kumar M, Skillman K, Duraisingh MT. Linking nutrient sensing and gene expression in Plasmodium falciparum blood-stage parasites. Mol Microbiol 2020; 115:891-900. [PMID: 33236377 DOI: 10.1111/mmi.14652] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 11/17/2020] [Accepted: 11/20/2020] [Indexed: 12/21/2022]
Abstract
Malaria is one of the most life-threatening infectious diseases worldwide, caused by infection of humans with parasites of the genus Plasmodium. The complex life cycle of Plasmodium parasites is shared between two hosts, with infection of multiple cell types, and the parasite needs to adapt for survival and transmission through significantly different metabolic environments. Within the blood-stage alone, parasites encounter changing levels of key nutrients, including sugars, amino acids, and lipids, due to differences in host dietary nutrition, cellular tropism, and pathogenesis. In this review, we consider the mechanisms that the most lethal of malaria parasites, Plasmodium falciparum, uses to sense nutrient levels and elicit changes in gene expression during blood-stage infections. These changes are brought about by several metabolic intermediates and their corresponding sensor proteins. Sensing of distinct nutritional signals can drive P. falciparum to alter the key blood-stage processes of proliferation, antigenic variation, and transmission.
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Affiliation(s)
- Manish Kumar
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, MA, USA
| | - Kristen Skillman
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, MA, USA
| | - Manoj T Duraisingh
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, MA, USA
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19
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Oyelade J, Isewon I, Aromolaran O, Uwoghiren E, Dokunmu T, Rotimi S, Aworunse O, Obembe O, Adebiyi E. Computational Identification of Metabolic Pathways of Plasmodium falciparum using the k-Shortest Path Algorithm. Int J Genomics 2019; 2019:1750291. [PMID: 31662957 PMCID: PMC6791207 DOI: 10.1155/2019/1750291] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 11/28/2018] [Accepted: 07/29/2019] [Indexed: 02/02/2023] Open
Abstract
Plasmodium falciparum, a malaria pathogen, has shown substantial resistance to treatment coupled with poor response to some vaccines thereby requiring urgent, holistic, and broad approach to prevent this endemic disease. Understanding the biology of the malaria parasite has been identified as a vital approach to overcome the threat of malaria. This study is aimed at identifying essential proteins unique to malaria parasites using a reconstructed iPfa genome-scale metabolic model (GEM) of the 3D7 strain of Plasmodium falciparum by filling gaps in the model with nineteen (19) metabolites and twenty-three (23) reactions obtained from the MetaCyc database. Twenty (20) currency metabolites were removed from the network because they have been identified to produce shortcuts that are biologically infeasible. The resulting modified iPfa GEM was a model using the k-shortest path algorithm to identify possible alternative metabolic pathways in glycolysis and pentose phosphate pathways of Plasmodium falciparum. Heuristic function was introduced for the optimal performance of the algorithm. To validate the prediction, the essentiality of the reactions in the reconstructed network was evaluated using betweenness centrality measure, which was applied to every reaction within the pathways considered in this study. Thirty-two (32) essential reactions were predicted among which our method validated fourteen (14) enzymes already predicted in the literature. The enzymatic proteins that catalyze these essential reactions were checked for homology with the host genome, and two (2) showed insignificant similarity, making them possible drug targets. In conclusion, the application of the intelligent search technique to the metabolic network of P. falciparum predicts potential biologically relevant alternative pathways using graph theory-based approach.
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Affiliation(s)
- Jelili Oyelade
- Department of Computer & Information Sciences, Covenant University, Ota, Nigeria
- Covenant University Bioinformatics Research Cluster (CUBRe), Ota, Nigeria
| | - Itunuoluwa Isewon
- Department of Computer & Information Sciences, Covenant University, Ota, Nigeria
- Covenant University Bioinformatics Research Cluster (CUBRe), Ota, Nigeria
| | - Olufemi Aromolaran
- Department of Computer & Information Sciences, Covenant University, Ota, Nigeria
- Covenant University Bioinformatics Research Cluster (CUBRe), Ota, Nigeria
| | - Efosa Uwoghiren
- Department of Computer & Information Sciences, Covenant University, Ota, Nigeria
- Covenant University Bioinformatics Research Cluster (CUBRe), Ota, Nigeria
| | - Titilope Dokunmu
- Covenant University Bioinformatics Research Cluster (CUBRe), Ota, Nigeria
- Department of Biochemistry, Covenant University, Ota, Nigeria
| | - Solomon Rotimi
- Covenant University Bioinformatics Research Cluster (CUBRe), Ota, Nigeria
- Department of Biochemistry, Covenant University, Ota, Nigeria
| | | | - Olawole Obembe
- Department of Biological Sciences, Covenant University, Ota, Nigeria
| | - Ezekiel Adebiyi
- Department of Computer & Information Sciences, Covenant University, Ota, Nigeria
- Covenant University Bioinformatics Research Cluster (CUBRe), Ota, Nigeria
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20
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Computational and experimental elucidation of Plasmodium falciparum phosphoethanolamine methyltransferase inhibitors: Pivotal drug target. PLoS One 2019; 14:e0221032. [PMID: 31437171 PMCID: PMC6705855 DOI: 10.1371/journal.pone.0221032] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 07/29/2019] [Indexed: 11/19/2022] Open
Abstract
INTRODUCTION Plasmodium falciparum synthesizes phosphatidylcholine for the membrane development through serine decarboxylase-phosphoethanolamine methyltransferase pathway for growth in human host. Phosphoethanolamine-methyltransferase (PfPMT) is a crucial enzyme for the synthesis of phosphocholine which is a precursor for phosphatidylcholine synthesis and is considered as a pivotal drug target as it is absent in the host. The inhibition of PfPMT may kill malaria parasite and hence is being considered as potential target for rational antimalarial drug designing. METHODS In this study, we have used computer aided drug designing (CADD) approaches to establish potential PfPMT inhibitors from Asinex compound library virtually screened for ADMET and the docking affinity. The selected compounds were tested for in-vitro schizonticidal, gametocidal and cytotoxicity activity. Nontoxic compounds were further studied for PfPMT enzyme specificity and antimalarial efficacy for P. berghei in albino mice model. RESULTS Our results have identified two nontoxic PfPMT competitive inhibitors ASN.1 and ASN.3 with better schizonticidal and gametocidal activity which were found to inhibit PfPMT at IC50 1.49μM and 2.31μM respectively. The promising reduction in parasitaemia was found both in orally (50 & 10 mg/kg) and intravenous (IV) (5& 1 mg/kg) however, the better growth inhibition was found in intravenous groups. CONCLUSION We report that the compounds containing Pyridinyl-Pyrimidine and Phenyl-Furan scaffolds as the potential inhibitors of PfPMT and thus may act as promising antimalarial inhibitor candidates which can be further optimized and used as leads for template based antimalarial drug development.
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21
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Singh J, Mansuri R, Vijay S, Sahoo GC, Sharma A, Kumar M. Docking predictions based Plasmodium falciparum phosphoethanolamine methyl transferase inhibitor identification and in-vitro antimalarial activity analysis. BMC Chem 2019; 13:43. [PMID: 31384791 PMCID: PMC6661969 DOI: 10.1186/s13065-019-0551-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Accepted: 03/08/2019] [Indexed: 11/10/2022] Open
Abstract
The increased multidrug resistance among antimalarial drugs produces the urgency of potent anti malarial to combat resistant malaria and the malaria burden worldwide. The protein which may prevent the growth or transmission of malaria parasite may be the great target for rational drug designing. Plasmodium falciparum phosphoethanolamine methyltransferase (Pfpmt) absent in human catalyzes triple methylation of ethanolamine into phosphocholine for phosphatidylcholine biosynthesis from serine decarboxylation phosphoethanolamine methyltransferase pathway for the membrane development at asexual as well as sexual stages of parasite. The Plasmodium requires production of membrane rapidly for growth and multiplication. Hence, the phosphoethanolamine methyltransferase of Plasmodium falciparum was selected as drug target for rational drug designing. Using Discovery studio 3.5 software the library of zinc compounds was screened against target and analyzed. The compounds with better druglike properties and docking affinity and binding interaction for target protein were procured for in vitro analysis against Plasmodium falciparum culture (IC50). Compounds ZINC02103914 and ZINC12882412 were found to have good druglike properties and affinity for Pfpmt also inhibited P. falciparum growth at very low µM IC50 concentration 3.0 µM and 2.1 µM respectively also found nontoxic in vitro against HEK-293 cells. Simulation study of best inhibitor revealed the specificity for the target protein. Hence, the compounds possessed the immense probability of being inhibitors of Pfpmt and may be optimized as antimalarial agent for combinational therapy to overcome the multidrug resistance and may also be used as template for optimization and rational drug designing.
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Affiliation(s)
- Jagbir Singh
- 1Division of Protein Biochemistry and Structural Biology, National Institute of Malaria Research (ICMR), Sector 8, Dwarka, New Delhi 110 077 India.,5Department of Pharmaceutical Sciences, Maharshi Dayanand University, Rohtak, India
| | - Rani Mansuri
- 2School of Pharmaceutical Sciences, Apeejay Stya University, Gurugram, India
| | - Sonam Vijay
- Division of ECD, Indian Council of India, New Delhi, India
| | - Ganesh Chandra Sahoo
- 4Department of Biomedical Sciences, Rajendra Memorial Research Institute, Patna, India
| | - Arun Sharma
- 1Division of Protein Biochemistry and Structural Biology, National Institute of Malaria Research (ICMR), Sector 8, Dwarka, New Delhi 110 077 India
| | - Mahesh Kumar
- 5Department of Pharmaceutical Sciences, Maharshi Dayanand University, Rohtak, India
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22
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Chen W, Taylor MC, Barrow RA, Croyal M, Masle J. Loss of Phosphoethanolamine N-Methyltransferases Abolishes Phosphatidylcholine Synthesis and Is Lethal. PLANT PHYSIOLOGY 2019; 179:124-142. [PMID: 30381317 PMCID: PMC6324220 DOI: 10.1104/pp.18.00694] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Accepted: 10/19/2018] [Indexed: 05/21/2023]
Abstract
Plants use several pathways to synthesize phosphatidylcholine (PC), the major phospholipid of eukaryotic cells. PC has important structural and signaling roles. One pathway plants use for synthesis is the phospho-base methylation pathway, which forms the head-group phosphocholine through the triple methylation of phosphoethanolamine (PEA) catalyzed by phosphoethanolamine N-methyltransferases (PEAMTs). Our understanding of that pathway and its physiological importance remains limited. We recently reported that disruption of Arabidopsis thaliana PEAMT1/NMT1 and PEAMT3/NMT3 induces severe PC deficiency leading to dwarfism and impaired development. However, the double nmt1 nmt3 knock-out mutant is viable. Here, we show that this is enabled by residual PEAMT activity through a third family member, NMT2. The triple nmt1 nmt2 nmt3 knock-out mutant cannot synthesize PC from PEA and is lethal. This shows that, unlike mammals and yeast, Arabidopsis cannot form PC from phosphatidyl ethanolamine (PE), and demonstrates that methylation of PEA is the sole, and vital, entry point to PC synthesis. We further show that Arabidopsis has evolved an expanded family of four nonredundant PEAMTs through gene duplication and alternate use of the NMT2 promoter. NMT2 encodes two PEAMT variants, which greatly differ in their ability to perform the initial phospho-base methylation of PEA. Five amino acids at the N terminus of PEAMTs are shown to each be critical for the catalysis of that step committing to PC synthesis. As a whole, these findings open new avenues for enzymatic engineering and the exploration of ways to better tune phosphocholine and PC synthesis to environmental conditions for improved plant performance.
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Affiliation(s)
- Weihua Chen
- Research School of Biology, The Australian National University, Canberra, Australian Capital Territory 2601, Australia
| | - Matthew C Taylor
- Land and Water Flagship, Commonwealth Scientific and Industrial Research Organization, Canberra, Australian Capital Territory 2601, Australia
| | - Russell A Barrow
- Research School of Chemistry, The Australian National University, Canberra, Australian Capital Territory 2601, Australia
| | - Mikaël Croyal
- CRNH Nantes, Mass Spectrometry Core facility, 8 Quai Moncousu BP-70721, Nantes cedex 1, France
| | - Josette Masle
- Research School of Biology, The Australian National University, Canberra, Australian Capital Territory 2601, Australia
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23
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Kilian N, Choi JY, Voelker DR, Ben Mamoun C. Role of phospholipid synthesis in the development and differentiation of malaria parasites in the blood. J Biol Chem 2018; 293:17308-17316. [PMID: 30287688 DOI: 10.1074/jbc.r118.003213] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The life cycle of malaria parasites in both their mammalian host and mosquito vector consists of multiple developmental stages that ensure proper replication and progeny survival. The transition between these stages is fueled by nutrients scavenged from the host and fed into specialized metabolic pathways of the parasite. One such pathway is used by Plasmodium falciparum, which causes the most severe form of human malaria, to synthesize its major phospholipids, phosphatidylcholine, phosphatidylethanolamine, and phosphatidylserine. Much is known about the enzymes involved in the synthesis of these phospholipids, and recent advances in genetic engineering, single-cell RNA-Seq analyses, and drug screening have provided new perspectives on the importance of some of these enzymes in parasite development and sexual differentiation and have identified targets for the development of new antimalarial drugs. This Minireview focuses on two phospholipid biosynthesis enzymes of P. falciparum that catalyze phosphoethanolamine transmethylation (PfPMT) and phosphatidylserine decarboxylation (PfPSD) during the blood stages of the parasite. We also discuss our current understanding of the biochemical, structural, and biological functions of these enzymes and highlight efforts to use them as antimalarial drug targets.
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Affiliation(s)
- Nicole Kilian
- From the Department of Internal Medicine, Section of Infectious Diseases, Yale School of Medicine, New Haven, Connecticut 06520 and
| | - Jae-Yeon Choi
- the Basic Science Section, Department of Medicine, National Jewish Health, Denver, Colorado 80206
| | - Dennis R Voelker
- the Basic Science Section, Department of Medicine, National Jewish Health, Denver, Colorado 80206
| | - Choukri Ben Mamoun
- From the Department of Internal Medicine, Section of Infectious Diseases, Yale School of Medicine, New Haven, Connecticut 06520 and
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24
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Chen W, Salari H, Taylor MC, Jost R, Berkowitz O, Barrow R, Qiu D, Branco R, Masle J. NMT1 and NMT3 N-Methyltransferase Activity Is Critical to Lipid Homeostasis, Morphogenesis, and Reproduction. PLANT PHYSIOLOGY 2018; 177:1605-1628. [PMID: 29777000 PMCID: PMC6084668 DOI: 10.1104/pp.18.00457] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Accepted: 05/10/2018] [Indexed: 05/24/2023]
Abstract
Phosphatidylcholine (PC) is a major membrane phospholipid and a precursor for major signaling molecules. Understanding its synthesis is important for improving plant growth, nutritional value, and resistance to stress. PC synthesis is complex, involving several interconnected pathways, one of which proceeds from serine-derived phosphoethanolamine to form phosphocholine through three sequential phospho-base methylations catalyzed by phosphoethanolamine N-methyltransferases (PEAMTs). The contribution of this pathway to the production of PC and plant growth has been a matter of some debate. Although a handful of individual PEAMTs have been described, there has not been any in planta investigation of a PEAMT family. Here, we provide a comparative functional analysis of two Arabidopsis (Arabidopsis thaliana) PEAMTs, NMT1 and the little known NMT3. Analysis of loss-of-function mutants demonstrates that NMT1 and NMT3 synergistically regulate PC homeostasis, phase transition at the shoot apex, coordinated organ development, and fertility through overlapping but also specific functions. The nmt1 nmt3 double mutant shows extensive sterility, drastically reduced PC concentrations, and altered lipid profiles. These findings demonstrate that the phospho-base methylation pathway makes a major contribution to PC synthesis in Arabidopsis and that NMT1 and NMT3 play major roles in its catalysis and the regulation of PC homeostasis as well as in plant growth and reproduction.
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Affiliation(s)
- Weihua Chen
- Research School of Biology, Australian National University, Canberra, Australian Capital Territory 2601, Australia
| | - Hooman Salari
- Agronomy and Plant Breeding Department, Razi University, Kermanshah 67155, Iran
| | - Matthew C Taylor
- Land and Water Flagship, Commonwealth Scientific and Industrial Research Organisation, Canberra, Australian Capital Territory 2601, Australia
| | - Ricarda Jost
- Research School of Biology, Australian National University, Canberra, Australian Capital Territory 2601, Australia
| | - Oliver Berkowitz
- Research School of Biology, Australian National University, Canberra, Australian Capital Territory 2601, Australia
| | - Russell Barrow
- Research School of Chemistry, Australian National University, Canberra, Australian Capital Territory 2601, Australia
| | - Deyun Qiu
- Research School of Biology, Australian National University, Canberra, Australian Capital Territory 2601, Australia
| | - Rémi Branco
- Research School of Biology, Australian National University, Canberra, Australian Capital Territory 2601, Australia
| | - Josette Masle
- Research School of Biology, Australian National University, Canberra, Australian Capital Territory 2601, Australia
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25
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Krishnan KM, Williamson KC. The proteasome as a target to combat malaria: hits and misses. Transl Res 2018; 198:40-47. [PMID: 30009761 PMCID: PMC6422032 DOI: 10.1016/j.trsl.2018.04.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Revised: 04/26/2018] [Accepted: 04/30/2018] [Indexed: 01/25/2023]
Abstract
The proteasome plays a vital role throughout the life cycle as Plasmodium parasites quickly adapt to a new host and undergo a series of morphologic changes during asexual replication and sexual differentiation. Plasmodium carries 3 different types of protease complexes: typical eukaryotic proteasome (26S) that resides in the cytoplasm and the nucleus, a prokaryotic proteasome homolog ClpQ that resides in the mitochondria, and a caseinolytic protease complex ClpP that resides in the apicoplast. In silico prediction in conjunction with immunoprecipitation analysis of ubiquitin conjugates have suggested that over half of the Plasmodium falciparum proteome during asexual reproduction are potential targets for ubiquitination. The marked potency of multiple classes of proteasome inhibitors against all stages of the life cycle, synergy with the current frontline antimalarial, artemisinin, and recent advances identifying differences between Plasmodium and human proteasomes strongly support further drug development efforts.
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Affiliation(s)
| | - Kim C Williamson
- Uniformed Services University of the Health Sciences, Bethesda, Maryland.
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26
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Schiafino-Ortega S, Baglioni E, Pérez-Moreno G, Marco PR, Marco C, González-Pacanowska D, Ruiz-Pérez LM, Carrasco-Jiménez MP, López-Cara LC. 1,2-Diphenoxiethane salts as potent antiplasmodial agents. Bioorg Med Chem Lett 2018; 28:2485-2489. [PMID: 29880399 DOI: 10.1016/j.bmcl.2018.05.060] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Revised: 05/25/2018] [Accepted: 05/30/2018] [Indexed: 01/22/2023]
Abstract
In this article we present a series of non-cytotoxic potent human choline kinase (CK) inhibitors that exhibit nanomolar antiplasmodial activity in vitro. The most active antiplasmodial compounds, 10a-b, bearing a pyridinium cationic head were inactive against CK, while compounds 10g and 10j with a quinolinium moiety exhibit moderate inhibition of both the parasite and the enzyme. The results point towards an additional mechanism of action unrelated to CK inhibition that remains to be established.
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Affiliation(s)
- Santiago Schiafino-Ortega
- Departamento de Química Farmacéutica y Orgánica, Facultad de Farmacia, Campus de Cartuja, 18071 Granada, Spain
| | - Eleonora Baglioni
- Departamento de Química Farmacéutica y Orgánica, Facultad de Farmacia, Campus de Cartuja, 18071 Granada, Spain
| | - Guiomar Pérez-Moreno
- Instituto de Parasitología y Biomedicina "López-Neyra", Consejo Superior de Investigaciones Científicas, Parque Tecnológico de Ciencias de la Salud, Avenida del Conocimiento 17, 18016 Armilla, Granada, Spain
| | - Pablo Rios Marco
- Departamento de Bioquímica y Biología Molecular I, Facultad de Ciencias, Campus Fuentenueva, 18071 Granada, Spain
| | - Carmen Marco
- Departamento de Bioquímica y Biología Molecular I, Facultad de Ciencias, Campus Fuentenueva, 18071 Granada, Spain
| | - Dolores González-Pacanowska
- Instituto de Parasitología y Biomedicina "López-Neyra", Consejo Superior de Investigaciones Científicas, Parque Tecnológico de Ciencias de la Salud, Avenida del Conocimiento 17, 18016 Armilla, Granada, Spain
| | - Luis Miguel Ruiz-Pérez
- Instituto de Parasitología y Biomedicina "López-Neyra", Consejo Superior de Investigaciones Científicas, Parque Tecnológico de Ciencias de la Salud, Avenida del Conocimiento 17, 18016 Armilla, Granada, Spain
| | - María Paz Carrasco-Jiménez
- Departamento de Bioquímica y Biología Molecular I, Facultad de Ciencias, Campus Fuentenueva, 18071 Granada, Spain
| | - Luisa Carlota López-Cara
- Departamento de Química Farmacéutica y Orgánica, Facultad de Farmacia, Campus de Cartuja, 18071 Granada, Spain.
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27
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Wein S, Ghezal S, Buré C, Maynadier M, Périgaud C, Vial HJ, Lefebvre-Tournier I, Wengelnik K, Cerdan R. Contribution of the precursors and interplay of the pathways in the phospholipid metabolism of the malaria parasite. J Lipid Res 2018; 59:1461-1471. [PMID: 29853527 PMCID: PMC6071779 DOI: 10.1194/jlr.m085589] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2018] [Revised: 05/24/2018] [Indexed: 12/17/2022] Open
Abstract
The malaria parasite, Plasmodium falciparum, develops and multiplies in the human erythrocyte. It needs to synthesize considerable amounts of phospholipids (PLs), principally phosphatidylcholine (PC), phosphatidylethanolamine (PE), and phosphatidylserine (PS). Several metabolic pathways coexist for their de novo biosynthesis, involving a dozen enzymes. Given the importance of these PLs for the survival of the parasite, we sought to determine their sources and to understand the connections and dependencies between the multiple pathways. We used three deuterated precursors (choline-d9, ethanolamine-d4, and serine-d3) to follow and quantify simultaneously their incorporations in the intermediate metabolites and the final PLs by LC/MS/MS. We show that PC is mainly derived from choline, itself provided by lysophosphatidylcholine contained in the serum. In the absence of choline, the parasite is able to use both other precursors, ethanolamine and serine. PE is almost equally synthesized from ethanolamine and serine, with both precursors being able to compensate for each other. Serine incorporated in PS is mainly derived from the degradation of host cell hemoglobin by the parasite. P. falciparum thus shows an unexpected adaptability of its PL synthesis pathways in response to different disturbances. These data provide new information by mapping the importance of the PL metabolic pathways of the malaria parasite and could be used to design future therapeutic approaches.
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Affiliation(s)
- Sharon Wein
- Dynamique des Interactions Membranaires Normales et Pathologiques, UMR 5235, CNRS-Université de Montpellier, 34095 Montpellier Cedex 05, France
| | - Salma Ghezal
- Institut des Biomolécules Max Mousseron, UMR 5247, CNRS-Université de Montpellier, 34095 Montpellier Cedex 05, France
| | - Corinne Buré
- Chimie et Biologie des Membranes et des Nanoobjets, UMR 5248, Centre de Génomique Fonctionnelle, Université Bordeaux 2, 33076 Bordeaux Cedex, France
| | - Marjorie Maynadier
- Dynamique des Interactions Membranaires Normales et Pathologiques, UMR 5235, CNRS-Université de Montpellier, 34095 Montpellier Cedex 05, France
| | - Christian Périgaud
- Institut des Biomolécules Max Mousseron, UMR 5247, CNRS-Université de Montpellier, 34095 Montpellier Cedex 05, France
| | - Henri J Vial
- Dynamique des Interactions Membranaires Normales et Pathologiques, UMR 5235, CNRS-Université de Montpellier, 34095 Montpellier Cedex 05, France
| | - Isabelle Lefebvre-Tournier
- Institut des Biomolécules Max Mousseron, UMR 5247, CNRS-Université de Montpellier, 34095 Montpellier Cedex 05, France
| | - Kai Wengelnik
- Dynamique des Interactions Membranaires Normales et Pathologiques, UMR 5235, CNRS-Université de Montpellier, 34095 Montpellier Cedex 05, France
| | - Rachel Cerdan
- Dynamique des Interactions Membranaires Normales et Pathologiques, UMR 5235, CNRS-Université de Montpellier, 34095 Montpellier Cedex 05, France
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28
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Krause RGE, Goldring JPD. Phosphoethanolamine-N-methyltransferase is a potential biomarker for the diagnosis of P. knowlesi and P. falciparum malaria. PLoS One 2018; 13:e0193833. [PMID: 29505599 PMCID: PMC5837800 DOI: 10.1371/journal.pone.0193833] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Accepted: 02/20/2018] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Plasmodium knowlesi is recognised as the main cause of human malaria in Southeast Asia. The disease is often misdiagnosed as P. falciparum or P. malariae infections by microscopy, and the disease is difficult to eliminate due to its presence in both humans and monkeys. P. knowlesi infections can rapidly cause severe disease and require prompt diagnosis and treatment. No protein biomarker exists for the rapid diagnostic test (RDT) detection of P. knowlesi infections. Plasmodium knowlesi infections can be diagnosed by PCR. METHODS AND PRINCIPAL FINDINGS Phosphoethanolamine-N-methyltransferase (PMT) is involved in malaria lipid biosynthesis and is not found in the human host. The P. falciparum, P. vivax and P. knowlesi PMT proteins were recombinantly expressed in BL21(DE3) Escherichia coli host cells, affinity purified and used to raise antibodies in chickens. Antibodies against each recombinant PMT protein all detected all three recombinant proteins and the native 29 kDa P. falciparum PMT protein on western blots and in ELISA. Antibodies against a PMT epitope (PLENNQYTDEGVKC) common to all three PMT orthologues detected all three proteins. Antibodies against unique peptides from each orthologue of PMT, PfCEVEHKYLHENKE, PvVYSIKEYNSLKDC, PkLYPTDEYNSLKDC detected only the parent protein in western blots and P. falciparum infected red blood cell lysates or blood lysates spiked with the respective proteins. Similar concentrations of PfPMT and the control, PfLDH, were detected in the same parasite lysate. The recombinant PfPMT protein was detected by a human anti-malaria antibody pool. CONCLUSION PMT, like the pan-specific LDH biomarker used in RDT tests, is both soluble, present at comparable concentrations in the parasite and constitutes a promising antimalarial drug target. PMT is absent from the human proteome. PMT has the potential as a biomarker for human malaria and in particular as the first P. knowlesi specific protein with diagnostic potential for the identification of a P. knowlesi infection.
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29
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Chiu JE, Thekkiniath J, Choi JY, Perrin BA, Lawres L, Plummer M, Virji AZ, Abraham A, Toh JY, Zandt MV, Aly ASI, Voelker DR, Mamoun CB. The antimalarial activity of the pantothenamide α-PanAm is via inhibition of pantothenate phosphorylation. Sci Rep 2017; 7:14234. [PMID: 29079738 PMCID: PMC5660193 DOI: 10.1038/s41598-017-14074-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Accepted: 10/06/2017] [Indexed: 12/21/2022] Open
Abstract
The biosynthesis of the major acyl carrier Coenzyme A from pantothenic acid (PA) is critical for survival of Plasmodium falciparum within human erythrocytes. Accordingly, a PA analog α-PanAm showed potent activity against blood stage parasites in vitro; however, its efficacy in vivo and its mode of action remain unknown. We developed a new synthesis route for α-PanAm and showed that the compound is highly effective against blood stages of drug-sensitive and -resistant P. falciparum strains, inhibits development of P. berghei in hepatocytes, and at doses up to 100 mg/kg also inhibits blood stage development of P. chabaudi in mice. We used yeast and its pantothenate kinase Cab1 as models to characterize mode of action of α-PanAm and found that α-PanAm inhibits yeast growth in a PA-dependent manner, and its potency increases dramatically in a yeast mutant with defective pantothenate kinase activity. Biochemical analyses using 14C-PA as a substrate demonstrated that α-PanAm is a competitive inhibitor of Cab1. Interestingly, biochemical and mass spectrometry analyses also showed that the compound is phosphorylated by Cab1. Together, these data suggest that α-PanAm exerts its antimicrobial activity by direct competition with the natural substrate PA for phosphorylation by the pantothenate kinase.
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Affiliation(s)
- Joy E Chiu
- Section of Infectious Diseases, Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Jose Thekkiniath
- Section of Infectious Diseases, Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Jae-Yeon Choi
- Basic Science Section, Department of Medicine, National Jewish Health, 1400 Jackson St, Denver, Colorado, 80206, USA
| | - Benjamin A Perrin
- Section of Infectious Diseases, Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Lauren Lawres
- Section of Infectious Diseases, Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Mark Plummer
- Section of Infectious Diseases, Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Azan Z Virji
- Section of Infectious Diseases, Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Amanah Abraham
- Department of Tropical Medicine, Tulane University School of Public Health and Tropical Medicine, New Orleans, LA, 70112, USA
| | - Justin Y Toh
- Section of Infectious Diseases, Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
| | | | - Ahmed S I Aly
- Department of Tropical Medicine, Tulane University School of Public Health and Tropical Medicine, New Orleans, LA, 70112, USA
| | - Dennis R Voelker
- Basic Science Section, Department of Medicine, National Jewish Health, 1400 Jackson St, Denver, Colorado, 80206, USA
| | - Choukri Ben Mamoun
- Section of Infectious Diseases, Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA.
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30
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Shandilya A, Hoda N, Khan S, Jameel E, Kumar J, Jayaram B. De novo lead optimization of triazine derivatives identifies potent antimalarials. J Mol Graph Model 2017; 71:96-103. [DOI: 10.1016/j.jmgm.2016.10.022] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 10/11/2016] [Accepted: 10/14/2016] [Indexed: 11/27/2022]
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31
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Witola WH, Cooks-Fagbodun S, Ordonez AR, Matthews K, Abugri DA, McHugh M. Knockdown of phosphoethanolamine transmethylation enzymes decreases viability of Haemonchus contortus. Vet Parasitol 2016; 223:1-6. [PMID: 27198768 DOI: 10.1016/j.vetpar.2016.04.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Revised: 04/06/2016] [Accepted: 04/07/2016] [Indexed: 01/19/2023]
Abstract
The phosphobase methylation pathway, in which phosphoethanolamine N-methyltransferases (PMTs) successively catalyze the methylation of phosphoethanolamine to phosphocholine, is essential in the free-living nematode Caenorhabditis elegans. Two PMT-encoding genes (HcPMT1 and HcPMT2) cloned from Haemonchus contortus have been shown, by in vitro assays, to possess enzymatic characteristics similar to those of C. elegans PMTs, but their physiological significance in H. contortus is yet to be elucidated. Therefore, in this study, we endeavored to determine the importance of HcPMT1 and HcPMT2 in the survival of H. contortus by adapting the use of phosphorodiamidate morpholino oligomers (PPMO) antisense approach to block the translation of HcPMT1 and HcPMT2 in the worms. We found that PPMOs targeting HcPMT1 and HcPMT2 down-regulated the expression of HcPMT1 and HcPMT2 proteins in adult H. contortus. Analysis of the effect of HcPMT1 and HcPMT2 knockdown showed that it significantly decreased worm motility and viability, thus validating HcPMT1 and HcPMT2 as essential enzymes for survival of H. contortus. Studies of gene function in H. contortus have been constrained by limited forward and reverse genetic technologies for use in H. contortus. Thus, our success in adaptation of use of PPMO antisense approach in H. contortus provides an important reverse genetic technological advance for studying this parasitic nematode of veterinary significance.
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Affiliation(s)
- William H Witola
- Department of Pathobiology, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, USA.
| | - Sheritta Cooks-Fagbodun
- Department of Agricultural and Environmental Sciences, Tuskegee University, Tuskegee, AL, USA
| | - Adriana Reyes Ordonez
- Department of Agricultural and Environmental Sciences, Tuskegee University, Tuskegee, AL, USA
| | - Kwame Matthews
- Department of Agricultural and Environmental Sciences, Tuskegee University, Tuskegee, AL, USA
| | - Daniel A Abugri
- Department of Agricultural and Environmental Sciences, Tuskegee University, Tuskegee, AL, USA
| | - Mark McHugh
- Department of Agricultural and Environmental Sciences, Tuskegee University, Tuskegee, AL, USA
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Witola WH, Matthews K, McHugh M. In vitro anthelmintic efficacy of inhibitors of phosphoethanolamine Methyltransferases in Haemonchus contortus. INTERNATIONAL JOURNAL FOR PARASITOLOGY-DRUGS AND DRUG RESISTANCE 2016; 6:44-53. [PMID: 27054063 PMCID: PMC4805780 DOI: 10.1016/j.ijpddr.2016.01.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/28/2015] [Revised: 01/12/2016] [Accepted: 01/12/2016] [Indexed: 12/03/2022]
Abstract
The essential phosphobase methylation pathway for synthesis of phosphocholine is unique to nematodes, protozoa and plants, and thus an attractive antiparasitic molecular target. Herein, we screened compounds from the National Cancer Institute (Developmental Therapeutics Program Open Chemical Repository) for specific inhibitory activity against Haemonchus contortus phosphoethanolamine methyltransferases (HcPMT1 and HcPMT2), and tested candidate compounds for anthelmintic activity against adult and third-stage larvae of H. contortus. We identified compound NSC-641296 with IC50 values of 8.3 ± 1.1 μM and 5.1 ± 1.8 μM for inhibition of the catalytic activity of HcPMT1 alone and HcPMT1/HcPMT2 combination, respectively. Additionally we identified compound NSC-668394 with inhibitory IC50 values of 5.9 ± 0.9 μM and 2.8 ± 0.6 μM for HcPMT1 alone and HcPMT1/HcPMT2 combination, respectively. Of the two compounds, NSC-641296 depicted significant anthelmintic activity against third-stage larvae (IC50 = 15 ± 2.9 μM) and adult stages (IC50 = 7 ± 2.9 μM) of H. contortus, with optimal effective in vitro concentrations being 2-fold and 4-fold, respectively, lower than its cytotoxic IC50 (29 ± 2.1 μM) in a mammalian cell line. Additionally, we identified two compounds, NSC-158011 and NSC-323241, with low inhibitory activity against the combined activity of HcPMT1 and HcPMT2, but both compounds did not show any anthelmintic activity against H. contortus. The identification of NSC-641296 that specifically inhibits a unique biosynthetic pathway in H. contortus and has anthelmintic activity against both larval and adult stages of H. contortus, provides impetus for the development of urgently needed new efficacious anthelmintics to address the prevailing problem of anthelmintic-resistant H. contortus. NSC-641296 and NSC-668394 inhibit HcPMT1 and HcPMT2 enzymes in Haemonchus contortus. NSC-641296 has in vitro anthelmintic activity against larvae and adult H. contortus. H. contortus HcPMT1 and HcPMT2 are two unique targets for anthelmintic development.
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Affiliation(s)
- William H Witola
- Department of Pathobiology, College of Veterinary Medicine, University of Illinois, Urbana-Champaign, USA.
| | - Kwame Matthews
- Department of Agricultural and Environmental Sciences, Tuskegee University, Tuskegee, AL, USA
| | - Mark McHugh
- Department of Agricultural and Environmental Sciences, Tuskegee University, Tuskegee, AL, USA
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33
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Choi JY, Kumar V, Pachikara N, Garg A, Lawres L, Toh JY, Voelker DR, Ben Mamoun C. Characterization of Plasmodium phosphatidylserine decarboxylase expressed in yeast and application for inhibitor screening. Mol Microbiol 2015; 99:999-1014. [PMID: 26585333 DOI: 10.1111/mmi.13280] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/16/2015] [Indexed: 11/30/2022]
Abstract
Phospholipid biosynthesis is critical for the development, differentiation and pathogenesis of several eukaryotic pathogens. Genetic studies have validated the pathway for phosphatidylethanolamine synthesis from phosphatidylserine catalyzed by phosphatidylserine decarboxylase enzymes (PSD) as a suitable target for development of antimicrobials; however no inhibitors of this class of enzymes have been discovered. We show that the Plasmodium falciparum PSD can restore the essential function of the yeast gene in strains requiring PSD for growth. Genetic, biochemical and metabolic analyses demonstrate that amino acids between positions 40 and 70 of the parasite enzyme are critical for proenzyme processing and decarboxylase activity. We used the essential role of Plasmodium PSD in yeast as a tool for screening a library of anti-malarials. One of these compounds is 7-chloro-N-(4-ethoxyphenyl)-4-quinolinamine, an inhibitor with potent activity against P. falciparum, and low toxicity toward mammalian cells. We synthesized an analog of this compound and showed that it inhibits PfPSD activity and eliminates Plasmodium yoelii infection in mice. These results highlight the importance of 4-quinolinamines as a novel class of drugs targeting membrane biogenesis via inhibition of PSD activity.
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Affiliation(s)
- Jae-Yeon Choi
- Basic Science Section, Department of Medicine, National Jewish Health, 1400 Jackson St, Denver, CO 80206, USA
| | - Vidya Kumar
- Department of Internal Medicine, Section of Infectious Diseases, Yale School of Medicine, 15 York St., New Haven, CT 06520, USA
| | - Niseema Pachikara
- Department of Internal Medicine, Section of Infectious Diseases, Yale School of Medicine, 15 York St., New Haven, CT 06520, USA
| | - Aprajita Garg
- Department of Internal Medicine, Section of Infectious Diseases, Yale School of Medicine, 15 York St., New Haven, CT 06520, USA
| | - Lauren Lawres
- Department of Internal Medicine, Section of Infectious Diseases, Yale School of Medicine, 15 York St., New Haven, CT 06520, USA
| | - Justin Y Toh
- Department of Internal Medicine, Section of Infectious Diseases, Yale School of Medicine, 15 York St., New Haven, CT 06520, USA
| | - Dennis R Voelker
- Basic Science Section, Department of Medicine, National Jewish Health, 1400 Jackson St, Denver, CO 80206, USA
| | - Choukri Ben Mamoun
- Department of Internal Medicine, Section of Infectious Diseases, Yale School of Medicine, 15 York St., New Haven, CT 06520, USA
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Targeting protein translation, RNA splicing, and degradation by morpholino-based conjugates in Plasmodium falciparum. Proc Natl Acad Sci U S A 2015; 112:11935-40. [PMID: 26351679 DOI: 10.1073/pnas.1515864112] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Identification and genetic validation of new targets from available genome sequences are critical steps toward the development of new potent and selective antimalarials. However, no methods are currently available for large-scale functional analysis of the Plasmodium falciparum genome. Here we present evidence for successful use of morpholino oligomers (MO) to mediate degradation of target mRNAs or to inhibit RNA splicing or translation of several genes of P. falciparum involved in chloroquine transport, apicoplast biogenesis, and phospholipid biosynthesis. Consistent with their role in the parasite life cycle, down-regulation of these essential genes resulted in inhibition of parasite development. We show that a MO conjugate that targets the chloroquine-resistant transporter PfCRT is effective against chloroquine-sensitive and -resistant parasites, causes enlarged digestive vacuoles, and renders chloroquine-resistant strains more sensitive to chloroquine. Similarly, we show that a MO conjugate that targets the PfDXR involved in apicoplast biogenesis inhibits parasite growth and that this defect can be rescued by addition of isopentenyl pyrophosphate. MO-based gene regulation is a viable alternative approach to functional analysis of the P. falciparum genome.
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Fang X, Reifman J, Wallqvist A. Modeling metabolism and stage-specific growth of Plasmodium falciparum HB3 during the intraerythrocytic developmental cycle. MOLECULAR BIOSYSTEMS 2015; 10:2526-37. [PMID: 25001103 DOI: 10.1039/c4mb00115j] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The human malaria parasite Plasmodium falciparum goes through a complex life cycle, including a roughly 48-hour-long intraerythrocytic developmental cycle (IDC) in human red blood cells. A better understanding of the metabolic processes required during the asexual blood-stage reproduction will enhance our basic knowledge of P. falciparum and help identify critical metabolic reactions and pathways associated with blood-stage malaria. We developed a metabolic network model that mechanistically links time-dependent gene expression, metabolism, and stage-specific growth, allowing us to predict the metabolic fluxes, the biomass production rates, and the timing of production of the different biomass components during the IDC. We predicted time- and stage-specific production of precursors and macromolecules for P. falciparum (strain HB3), allowing us to link specific metabolites to specific physiological functions. For example, we hypothesized that coenzyme A might be involved in late-IDC DNA replication and cell division. Moreover, the predicted ATP metabolism indicated that energy was mainly produced from glycolysis and utilized for non-metabolic processes. Finally, we used the model to classify the entire tricarboxylic acid cycle into segments, each with a distinct function, such as superoxide detoxification, glutamate/glutamine processing, and metabolism of fumarate as a byproduct of purine biosynthesis. By capturing the normal metabolic and growth progression in P. falciparum during the IDC, our model provides a starting point for further elucidation of strain-specific metabolic activity, host-parasite interactions, stress-induced metabolic responses, and metabolic responses to antimalarial drugs and drug candidates.
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Affiliation(s)
- Xin Fang
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, U.S. Army Medical Research and Materiel Command, Ft. Detrick, MD 21702, USA.
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Garg A, Lukk T, Kumar V, Choi JY, Augagneur Y, Voelker DR, Nair S, Ben Mamoun C. Structure, function and inhibition of the phosphoethanolamine methyltransferases of the human malaria parasites Plasmodium vivax and Plasmodium knowlesi. Sci Rep 2015; 5:9064. [PMID: 25761669 PMCID: PMC4357015 DOI: 10.1038/srep09064] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Accepted: 02/03/2015] [Indexed: 11/09/2022] Open
Abstract
Phosphoethanolamine methyltransferases (PMTs) catalyze the three-step methylation of phosphoethanolamine to form phosphocholine, a critical step in the synthesis of phosphatidylcholine in a select number of eukaryotes including human malaria parasites, nematodes and plants. Genetic studies in the malaria parasite Plasmodium falciparum have shown that the methyltransferase PfPMT plays a critical function in parasite development and differentiation. The presence of PMT orthologs in other malaria parasites that infect humans and their absence in mammals make them ideal targets for the development of selective antimalarials with broad specificity against different Plasmodium species. Here we describe the X-ray structures and biochemical properties of PMT orthologs from Plasmodium vivax and Plasmodium knowlesi and show that both enzymes are inhibited by amodiaquine and NSC158011, two drugs with potent antimalarial activity. Metabolic studies in a yeast mutant that relies on PkPMT or PvPMT for survival demonstrated that these compounds inhibit phosphatidylcholine biosynthesis from ethanolamine. Our structural and functional data provide insights into the mechanism of catalysis and inhibition of PMT enzymes and set the stage for a better design of more specific and selective antimalarial drugs.
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Affiliation(s)
- Aprajita Garg
- Department of Internal Medicine, Yale University School of Medicine, New Haven CT, 06520 USA
| | - Tiit Lukk
- 1] Department of Biochemistry, University of Illinois at Urbana-Champaign [2] Cornell High Energy Synchrotron Source, Cornell University
| | - Vidya Kumar
- Department of Internal Medicine, Yale University School of Medicine, New Haven CT, 06520 USA
| | - Jae-Yeon Choi
- Basic Science Section, Department of Medicine, National Jewish Health, Denver, Colorado 80206
| | - Yoann Augagneur
- Department of Internal Medicine, Yale University School of Medicine, New Haven CT, 06520 USA
| | - Dennis R Voelker
- Basic Science Section, Department of Medicine, National Jewish Health, Denver, Colorado 80206
| | - Satish Nair
- Department of Biochemistry, University of Illinois at Urbana-Champaign
| | - Choukri Ben Mamoun
- Department of Internal Medicine, Yale University School of Medicine, New Haven CT, 06520 USA
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Saen-Oon S, Lee SG, Jez JM, Guallar V. An alternative mechanism for the methylation of phosphoethanolamine catalyzed by Plasmodium falciparum phosphoethanolamine methyltransferase. J Biol Chem 2014; 289:33815-25. [PMID: 25288796 DOI: 10.1074/jbc.m114.611319] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The phosphobase methylation pathway catalyzed by the phosphoethanolamine methyltransferase in Plasmodium falciparum (PfPMT), the malaria parasite, offers an attractive target for anti-parasitic drug development. PfPMT methylates phosphoethanolamine (pEA) to phosphocholine for use in membrane biogenesis. Quantum mechanics and molecular mechanics (QM/MM) calculations tested the proposed reaction mechanism for methylation of pEA involving the previously identified Tyr-19-His-132 dyad, which indicated an energetically unfavorable mechanism. Instead, the QM/MM calculations suggested an alternative mechanism involving Asp-128. The reaction coordinate involves the stepwise transfer of a proton to Asp-128 via a bridging water molecule followed by a typical Sn2-type methyl transfer from S-adenosylmethionine to pEA. Functional analysis of the D128A, D128E, D128Q, and D128N PfPMT mutants shows a loss of activity with pEA but not with the final substrate of the methylation pathway. X-ray crystal structures of the PfPMT-D128A mutant in complex with S-adenosylhomocysteine and either pEA or phosphocholine reveal how mutation of Asp-128 disrupts a hydrogen bond network in the active site. The combined QM/MM, biochemical, and structural studies identify a key role for Asp-128 in the initial step of the phosphobase methylation pathway in Plasmodium and provide molecular insight on the evolution of multiple activities in the active site of the PMT.
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Affiliation(s)
- Suwipa Saen-Oon
- From the Joint Barcelona Supercomputing Center-Centre for Genomic Regulation-Institute for Research in Biomedicine Research Program, Carrer de Jordi Girona 29, 08034 Barcelona, Spain
| | - Soon Goo Lee
- the Department of Biology, Washington University, St. Louis, Missouri 63130, and
| | - Joseph M Jez
- the Department of Biology, Washington University, St. Louis, Missouri 63130, and
| | - Victor Guallar
- From the Joint Barcelona Supercomputing Center-Centre for Genomic Regulation-Institute for Research in Biomedicine Research Program, Carrer de Jordi Girona 29, 08034 Barcelona, Spain, the Catalan Institution for Research and Advanced Studies, Barcelona 08010, Spain
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Abstract
Despite a century of control and eradication campaigns, malaria remains one of the world's most devastating diseases. Our once-powerful therapeutic weapons are losing the war against the Plasmodium parasite, whose ability to rapidly develop and spread drug resistance hamper past and present malaria-control efforts. Finding new and effective treatments for malaria is now a top global health priority, fuelling an increase in funding and promoting open-source collaborations between researchers and pharmaceutical consortia around the world. The result of this is rapid advances in drug discovery approaches and technologies, with three major methods for antimalarial drug development emerging: (i) chemistry-based, (ii) target-based, and (iii) cell-based. Common to all three of these approaches is the unique ability of structural biology to inform and accelerate drug development. Where possible, SBDD (structure-based drug discovery) is a foundation for antimalarial drug development programmes, and has been invaluable to the development of a number of current pre-clinical and clinical candidates. However, as we expand our understanding of the malarial life cycle and mechanisms of resistance development, SBDD as a field must continue to evolve in order to develop compounds that adhere to the ideal characteristics for novel antimalarial therapeutics and to avoid high attrition rates pre- and post-clinic. In the present review, we aim to examine the contribution that SBDD has made to current antimalarial drug development efforts, covering hit discovery to lead optimization and prevention of parasite resistance. Finally, the potential for structural biology, particularly high-throughput structural genomics programmes, to identify future targets for drug discovery are discussed.
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Exploring Drug Targets in Isoprenoid Biosynthetic Pathway for Plasmodium falciparum. Biochem Res Int 2014; 2014:657189. [PMID: 24864210 PMCID: PMC4017727 DOI: 10.1155/2014/657189] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2013] [Revised: 02/07/2014] [Accepted: 02/07/2014] [Indexed: 12/28/2022] Open
Abstract
Emergence of rapid drug resistance to existing antimalarial drugs in Plasmodium falciparum has created the need for prediction of novel targets as well as leads derived from original molecules with improved activity against a validated drug target. The malaria parasite has a plant plastid-like apicoplast. To overcome the problem of falciparum malaria, the metabolic pathways in parasite apicoplast have been used as antimalarial drug targets. Among several pathways in apicoplast, isoprenoid biosynthesis is one of the important pathways for parasite as its multiplication in human erythrocytes requires isoprenoids. Therefore targeting this pathway and exploring leads with improved activity is a highly attractive approach. This report has explored progress towards the study of proteins and inhibitors of isoprenoid biosynthesis pathway. For more comprehensive analysis, antimalarial drug-protein interaction has been covered.
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Sen P, Vial HJ, Radulescu O. Kinetic modelling of phospholipid synthesis in Plasmodium knowlesi unravels crucial steps and relative importance of multiple pathways. BMC SYSTEMS BIOLOGY 2013; 7:123. [PMID: 24209716 PMCID: PMC3829661 DOI: 10.1186/1752-0509-7-123] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Accepted: 11/01/2013] [Indexed: 12/04/2022]
Abstract
BACKGROUND Plasmodium is the causal parasite of malaria, infectious disease responsible for the death of up to one million people each year. Glycerophospholipid and consequently membrane biosynthesis are essential for the survival of the parasite and are targeted by a new class of antimalarial drugs developed in our lab. In order to understand the highly redundant phospholipid synthethic pathways and eventual mechanism of resistance to various drugs, an organism specific kinetic model of these metabolic pathways need to be developed in Plasmodium species. RESULTS Fluxomic data were used to build a quantitative kinetic model of glycerophospholipid pathways in Plasmodium knowlesi. In vitro incorporation dynamics of phospholipids unravels multiple synthetic pathways. A detailed metabolic network with values of the kinetic parameters (maximum rates and Michaelis constants) has been built. In order to obtain a global search in the parameter space, we have designed a hybrid, discrete and continuous, optimization method. Discrete parameters were used to sample the cone of admissible fluxes, whereas the continuous Michaelis and maximum rates constants were obtained by local minimization of an objective function.The model was used to predict the distribution of fluxes within the network of various metabolic precursors.The quantitative analysis was used to understand eventual links between different pathways. The major source of phosphatidylcholine (PC) is the CDP-choline Kennedy pathway.In silico knock-out experiments showed comparable importance of phosphoethanolamine-N-methyltransferase (PMT) and phosphatidylethanolamine-N-methyltransferase (PEMT) for PC synthesis.The flux values indicate that, major part of serine derived phosphatidylethanolamine (PE) is formed via serine decarboxylation, whereas major part of phosphatidylserine (PS) is formed by base-exchange reactions.Sensitivity analysis of CDP-choline pathway shows that the carrier-mediated choline entry into the parasite and the phosphocholine cytidylyltransferase reaction have the largest sensitivity coefficients in this pathway, but does not distinguish a reaction as an unique rate-limiting step. CONCLUSION We provide a fully parametrized kinetic model for the multiple phospholipid synthetic pathways in P. knowlesi. This model has been used to clarify the relative importance of the various reactions in these metabolic pathways. Future work extensions of this modelling strategy will serve to elucidate the regulatory mechanisms governing the development of Plasmodium during its blood stages, as well as the mechanisms of action of drugs on membrane biosynthetic pathways and eventual mechanisms of resistance.
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Affiliation(s)
- Partho Sen
- Dynamique des Interactions Membranaires Normales et Pathologiques, UMR 5235 CNRS, UM1, UM2, CP 107, Place Eugène Bataillon, 34095 Montpellier Cedex 5, France
| | - Henri J Vial
- Dynamique des Interactions Membranaires Normales et Pathologiques, UMR 5235 CNRS, UM1, UM2, CP 107, Place Eugène Bataillon, 34095 Montpellier Cedex 5, France
| | - Ovidiu Radulescu
- Dynamique des Interactions Membranaires Normales et Pathologiques, UMR 5235 CNRS, UM1, UM2, CP 107, Place Eugène Bataillon, 34095 Montpellier Cedex 5, France
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Plasmodium falciparum phosphoethanolamine methyltransferase is essential for malaria transmission. Proc Natl Acad Sci U S A 2013; 110:18262-7. [PMID: 24145416 DOI: 10.1073/pnas.1313965110] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Efficient transmission of Plasmodium species between humans and Anopheles mosquitoes is a major contributor to the global burden of malaria. Gametocytogenesis, the process by which parasites switch from asexual replication within human erythrocytes to produce male and female gametocytes, is a critical step in malaria transmission and Plasmodium genetic diversity. Nothing is known about the pathways that regulate gametocytogenesis and only few of the current drugs that inhibit asexual replication are also capable of inhibiting gametocyte development and blocking malaria transmission. Here we provide genetic and pharmacological evidence indicating that the pathway for synthesis of phosphatidylcholine in Plasmodium falciparum membranes from host serine is essential for parasite gametocytogenesis and malaria transmission. Parasites lacking the phosphoethanolamine N-methyltransferase enzyme, which catalyzes the limiting step in this pathway, are severely altered in gametocyte development, are incapable of producing mature-stage gametocytes, and are not transmitted to mosquitoes. Chemical screening identified 11 inhibitors of phosphoethanolamine N-methyltransferase that block parasite intraerythrocytic asexual replication and gametocyte differentiation in the low micromolar range. Kinetic studies in vitro as well as functional complementation assays and lipid metabolic analyses in vivo on the most promising inhibitor NSC-158011 further demonstrated the specificity of inhibition. These studies set the stage for further optimization of NSC-158011 for development of a class of dual activity antimalarials to block both intraerythrocytic asexual replication and gametocytogenesis.
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A biosynthetic enzyme worms its way out of a conserved mechanism. Structure 2013; 21:1719-20. [PMID: 24119669 DOI: 10.1016/j.str.2013.09.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Reduced glycerol incorporation into phospholipids contributes to impaired intra-erythrocytic growth of glycerol kinase knockout Plasmodium falciparum parasites. Biochim Biophys Acta Gen Subj 2013; 1830:5326-34. [PMID: 23954205 DOI: 10.1016/j.bbagen.2013.08.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Revised: 07/12/2013] [Accepted: 08/09/2013] [Indexed: 11/22/2022]
Abstract
BACKGROUND Malaria is a devastating disease and Plasmodium falciparum is the most lethal parasite infecting humans. Understanding the biology of this parasite is vital in identifying potential novel drug targets. During every 48-hour intra-erythrocytic asexual replication cycle, a single parasite can produce up to 32 progeny. This extensive proliferation implies that parasites require substantial amounts of lipid precursors for membrane biogenesis. Glycerol kinase is a highly conserved enzyme that functions at the interface of lipid synthesis and carbohydrate metabolism. P. falciparum glycerol kinase catalyzes the ATP-dependent phosphorylation of glycerol to glycerol-3-phosphate, a major phospholipid precursor. METHODS The P. falciparum glycerol kinase gene was disrupted using double crossover homologous DNA recombination to generate a knockout parasite line. Southern hybridization and mRNA analysis were used to verify gene disruption. Parasite growth rates were monitored by flow cytometry. Radiolabelling studies were used to assess incorporation of glycerol into parasite phospholipids. RESULTS Disruption of the P. falciparum glycerol kinase gene produced viable parasites, but their growth was significantly reduced to 56.5±1.8% when compared to wild type parasites. (14)C-glycerol incorporation into the major phospholipids of the parasite membrane, phosphatidylcholine and phosphatidylethanolamine, was 48.4±10.8% and 53.1±5.7% relative to an equivalent number of wild type parasites. CONCLUSIONS P. falciparum glycerol kinase is required for optimal intra-erythrocytic asexual parasite development. Exogenous glycerol may be used as an alternative carbon source for P. falciparum phospholipid biogenesis, despite the lack of glycerol kinase to generate glycerol-3-phosphate. GENERAL SIGNIFICANCE These studies provide new insight into glycerolipid metabolism in P. falciparum.
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Lipid synthesis in protozoan parasites: a comparison between kinetoplastids and apicomplexans. Prog Lipid Res 2013; 52:488-512. [PMID: 23827884 DOI: 10.1016/j.plipres.2013.06.003] [Citation(s) in RCA: 103] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2013] [Revised: 06/16/2013] [Accepted: 06/17/2013] [Indexed: 12/22/2022]
Abstract
Lipid metabolism is of crucial importance for pathogens. Lipids serve as cellular building blocks, signalling molecules, energy stores, posttranslational modifiers, and pathogenesis factors. Parasites rely on a complex system of uptake and synthesis mechanisms to satisfy their lipid needs. The parameters of this system change dramatically as the parasite transits through the various stages of its life cycle. Here we discuss the tremendous recent advances that have been made in the understanding of the synthesis and uptake pathways for fatty acids and phospholipids in apicomplexan and kinetoplastid parasites, including Plasmodium, Toxoplasma, Cryptosporidium, Trypanosoma and Leishmania. Lipid synthesis differs in significant ways between parasites from both phyla and the human host. Parasites have acquired novel pathways through endosymbiosis, as in the case of the apicoplast, have dramatically reshaped substrate and product profiles, and have evolved specialized lipids to interact with or manipulate the host. These differences potentially provide opportunities for drug development. We outline the lipid pathways for key species in detail as they progress through the developmental cycle and highlight those that are of particular importance to the biology of the pathogens and/or are the most promising targets for parasite-specific treatment.
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Augagneur Y, Jaubert L, Schiavoni M, Pachikara N, Garg A, Usmani-Brown S, Wesolowski D, Zeller S, Ghosal A, Cornillot E, Said HM, Kumar P, Altman S, Ben Mamoun C. Identification and functional analysis of the primary pantothenate transporter, PfPAT, of the human malaria parasite Plasmodium falciparum. J Biol Chem 2013; 288:20558-67. [PMID: 23729665 DOI: 10.1074/jbc.m113.482992] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The human malaria parasite Plasmodium falciparum is absolutely dependent on the acquisition of host pantothenate for its development within human erythrocytes. Although the biochemical properties of this transport have been characterized, the molecular identity of the parasite-encoded pantothenate transporter remains unknown. Here we report the identification and functional characterization of the first protozoan pantothenate transporter, PfPAT, from P. falciparum. We show using cell biological, biochemical, and genetic analyses that this transporter is localized to the parasite plasma membrane and plays an essential role in parasite intraerythrocytic development. We have targeted PfPAT to the yeast plasma membrane and showed that the transporter complements the growth defect of the yeast fen2Δ pantothenate transporter-deficient mutant and mediates the entry of the fungicide drug, fenpropimorph. Our studies in P. falciparum revealed that fenpropimorph inhibits the intraerythrocytic development of both chloroquine- and pyrimethamine-resistant P. falciparum strains with potency equal or better than that of currently available pantothenate analogs. The essential function of PfPAT and its ability to deliver both pantothenate and fenpropimorph makes it an attractive target for the development and delivery of new classes of antimalarial drugs.
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Affiliation(s)
- Yoann Augagneur
- Department of Medicine, Yale University School of Medicine, New Haven, Connecticut 06520, USA
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Bezsonova I, Rujan I, Bobenchik AM, Gorbatyuk V, Maciejewski MW, Gorbatyuk O, Hao B, Arthanari H, Ben Mamoun C, Hoch JC. (1)H, (13)C, and (15)N chemical shift assignments for PfPMT, a phosphoethanolamine methyltransferase from Plasmodium falciparum. BIOMOLECULAR NMR ASSIGNMENTS 2013; 7:17-20. [PMID: 22392340 PMCID: PMC3882757 DOI: 10.1007/s12104-012-9372-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2012] [Accepted: 02/20/2012] [Indexed: 05/31/2023]
Abstract
Phosphoethanolamine methyltransferases (PMTs also known as PEAMTs) catalyze the three-step s-adenosyl-methionione-dependent methylation of phosphoethanolamine to form phosphocholine. These enzymes play an important function in the synthesis of phosphatidylcholine, the major phospholipid in the membranes of lower and higher eukaryotes, as well as in the production of the compatible solute and osmoprotectant glycine betaine in plants. Genetic studies in plants, Caenhorhabditis elegans and Plasmodium falciparum have demonstrated that disruption of PMT activity results in severe defects in important cellular processes such as development, replication, survival and sexual maturation and differentiation. Here we report chemical shift assignments for PfPMT, the PMT from Plasmodium falciparum. X-ray crystal structures have been recently reported for complexes of PfPMT, but the structure of the apoenzyme remains unknown. The solution structure of the apoenzyme will help to elucidate important details of the mechanism of substrate binding by PfPMT, as residues comprising the substrate binding site are inaccessible to solvent in the conformation evident in the available crystal structures. In addition to enabling determination of the solution structure of the apoenzyme, the assignments will facilitate additional investigations into the interaction of PfPMT with its substrates and inhibitors.
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Affiliation(s)
- Irina Bezsonova
- Department of Molecular, Microbial and Structural Biology, University of Connecticut Health Center, 263 Farmington Ave., Farmington, CT 6030-3305, USA
| | - Iulian Rujan
- Department of Molecular, Microbial and Structural Biology, University of Connecticut Health Center, 263 Farmington Ave., Farmington, CT 6030-3305, USA
| | - April M. Bobenchik
- Section of Infectious Diseases, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Vitaliy Gorbatyuk
- Department of Molecular, Microbial and Structural Biology, University of Connecticut Health Center, 263 Farmington Ave., Farmington, CT 6030-3305, USA
| | - Mark W. Maciejewski
- Department of Molecular, Microbial and Structural Biology, University of Connecticut Health Center, 263 Farmington Ave., Farmington, CT 6030-3305, USA
| | - Oksana Gorbatyuk
- Department of Molecular, Microbial and Structural Biology, University of Connecticut Health Center, 263 Farmington Ave., Farmington, CT 6030-3305, USA
| | - Bing Hao
- Department of Molecular, Microbial and Structural Biology, University of Connecticut Health Center, 263 Farmington Ave., Farmington, CT 6030-3305, USA
| | - Haribabu Arthanari
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Ave., Boston, MA 02115, USA
| | - Choukri Ben Mamoun
- Section of Infectious Diseases, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Jeffrey C. Hoch
- Department of Molecular, Microbial and Structural Biology, University of Connecticut Health Center, 263 Farmington Ave., Farmington, CT 6030-3305, USA
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Acharya P, Pallavi R, Chandran S, Chakravarti H, Middha S, Acharya J, Kochar S, Kochar D, Subudhi A, Boopathi AP, Garg S, Das A, Tatu U. A glimpse into the clinical proteome of human malaria parasites Plasmodium falciparum and Plasmodium vivax. Proteomics Clin Appl 2012; 3:1314-25. [PMID: 21136953 DOI: 10.1002/prca.200900090] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Malaria causes a worldwide annual mortality of about a million people. Rapidly evolving drug-resistant species of the parasite have created a pressing need for the identification of new drug targets and vaccine candidates. By developing fractionation protocols to enrich parasites from low-parasitemia patient samples, we have carried out the first ever proteomics analysis of clinical isolates of early stages of Plasmodium falciparum (Pf) and P. vivax. Patient-derived malarial parasites were directly processed and analyzed using shotgun proteomics approach using high-sensitivity MS for protein identification. Our study revealed about 100 parasite-coded gene products that included many known drug targets such as Pf hypoxanthine guanine phosphoribosyl transferase, Pf L-lactate dehydrogenase, and Plasmepsins. In addition, our study reports the expression of several parasite proteins in clinical ring stages that have never been reported in the ring stages of the laboratory-cultivated parasite strain. This proof-of-principle study represents a noteworthy step forward in our understanding of pathways elaborated by the parasite within the malaria patient and will pave the way towards identification of new drug and vaccine targets that can aid malaria therapy.
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Affiliation(s)
- Pragyan Acharya
- Department of Biochemistry, Indian Institute of Science, Bangalore, Karnataka, India
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Lee SG, Alpert TD, Jez JM. Crystal structure of phosphoethanolamine methyltransferase from Plasmodium falciparum in complex with amodiaquine. Bioorg Med Chem Lett 2012; 22:4990-3. [PMID: 22771008 PMCID: PMC3401361 DOI: 10.1016/j.bmcl.2012.06.032] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2012] [Revised: 06/05/2012] [Accepted: 06/11/2012] [Indexed: 11/16/2022]
Abstract
Phosphoethanolamine N-methyltransferase (PMT) is essential for phospholipid biogenesis in the malarial parasite Plasmodium falciparum. PfPMT catalyzes the triple methylation of phosphoethanolamine to produce phosphocholine, which is then used for phosphatidylcholine synthesis. Here we describe the 2.0Å resolution X-ray crystal structure of PfPMT in complex with amodiaquine. To better characterize inhibition of PfPMT by amodiaquine, we determined the IC(50) values of a series of aminoquinolines using a direct radiochemical assay. Both structural and functional analyses provide a possible approach for the development of new small molecule inhibitors of PfPMT.
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Affiliation(s)
- Soon Goo Lee
- Department of Biology, Washington University, St. Louis, MO 63130, USA
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49
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Gene selective mRNA cleavage inhibits the development of Plasmodium falciparum. Proc Natl Acad Sci U S A 2012; 109:6235-40. [PMID: 22474358 DOI: 10.1073/pnas.1203516109] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Unique peptide-morpholino oligomer (PMO) conjugates have been designed to bind and promote the cleavage of specific mRNA as a tool to inhibit gene function and parasite growth. The new conjugates were validated using the P. falciparum gyrase mRNA as a target (PfGyrA). Assays in vitro demonstrated a selective degradation of the PfGyrA mRNA directed by the external guide sequences, which are morpholino oligomers in the conjugates. Fluorescence microscopy revealed that labeled conjugates are delivered into Plasmodium-infected erythrocytes during all intraerythrocytic stages of parasite development. Consistent with the expression of PfGyrA in all stages of parasite development, proliferation assays showed that these conjugates have potent antimalarial activity, blocking early development, maturation, and replication of the parasite. The conjugates were equally effective against drug sensitive and resistant P. falciparum strains. The potency, selectivity, and predicted safety of PMO conjugates make this approach attractive for the development of a unique class of target-specific antimalarials and for large-scale functional analysis of the malarial genome.
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Sampels V, Hartmann A, Dietrich I, Coppens I, Sheiner L, Striepen B, Herrmann A, Lucius R, Gupta N. Conditional mutagenesis of a novel choline kinase demonstrates plasticity of phosphatidylcholine biogenesis and gene expression in Toxoplasma gondii. J Biol Chem 2012; 287:16289-99. [PMID: 22451671 DOI: 10.1074/jbc.m112.347138] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The obligate intracellular and promiscuous protozoan parasite Toxoplasma gondii needs an extensive membrane biogenesis that must be satisfied irrespective of its host-cell milieu. We show that the synthesis of the major lipid in T. gondii, phosphatidylcholine (PtdCho), is initiated by a novel choline kinase (TgCK). Full-length (∼70-kDa) TgCK displayed a low affinity for choline (K(m) ∼0.77 mM) and harbors a unique N-terminal hydrophobic peptide that is required for the formation of enzyme oligomers in the parasite cytosol but not for activity. Conditional mutagenesis of the TgCK gene in T. gondii attenuated the protein level by ∼60%, which was abolished in the off state of the mutant (Δtgck(i)). Unexpectedly, the mutant was not impaired in its growth and exhibited a normal PtdCho biogenesis. The parasite compensated for the loss of full-length TgCK by two potential 53- and 44-kDa isoforms expressed through a cryptic promoter identified within exon 1. TgCK-Exon1 alone was sufficient in driving the expression of GFP in E. coli. The presence of a cryptic promoter correlated with the persistent enzyme activity, PtdCho synthesis, and susceptibility of T. gondii to a choline analog, dimethylethanolamine. Quite notably, the mutant displayed a regular growth in the off state despite a 35% decline in PtdCho content and lipid synthesis, suggesting a compositional flexibility in the membranes of the parasite. The observed plasticity of gene expression and membrane biogenesis can ensure a faithful replication and adaptation of T. gondii in disparate host or nutrient environments.
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Affiliation(s)
- Vera Sampels
- Institute of Biology, Department of Molecular Parasitology, Humboldt University, Philippstrasse 13, House 14, 10115 Berlin, Germany
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