1
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Wyss MT, Heuer C, Herwerth M. The bumpy road of purinergic inhibitors to clinical application in immune-mediated diseases. Neural Regen Res 2024; 19:1206-1211. [PMID: 37905866 DOI: 10.4103/1673-5374.386405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 09/05/2023] [Indexed: 11/02/2023] Open
Abstract
ABSTRACT Purinergic signaling plays important roles throughout the body in the regulation of organ functions during and following the disruption of homeostasis. This is also reflected by the widespread expression of two families of purinergic receptors (P1 and P2) with numerous subtypes. In the last few decades, there has been increasing evidence that purinergic signaling plays an important role in the regulation of immune functions. Mainly, signals mediated by P2 receptors have been shown to contribute to immune system-mediated pathologies. Thus, interference with P2 receptors may be a promising strategy for the modulation of immune responses. Although only a few clinical studies have been conducted in isolated entities with limited success, preclinical work suggests that the use of P2 receptor inhibitors may bear some promise in various autoimmune diseases. Despite the association of P2 receptors with several disorders from this field, the use of P2 receptor antagonists in clinical therapy is still very scarce. In this narrative review, we briefly review the involvement of the purinergic system in immunological responses and clinical studies on the effect of purinergic inhibition on autoimmune processes. We then open the aperture a bit and show some preclinical studies demonstrating a potential effect of purinergic blockade on autoimmune events. Using suramin, a non-specific purinergic inhibitor, as an example, we further show that off-target effects could be responsible for observed effects in immunological settings, which may have interesting implications. Overall, we believe that it is worthwhile to further investigate this hitherto underexplored area.
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Affiliation(s)
- Matthias T Wyss
- Institute of Pharmacology and Toxicology, University of Zurich, Zürich, Switzerland
- Neuroscience Center Zurich (ZNZ), University of Zurich and ETH Zurich, Zürich, Switzerland
| | - Christine Heuer
- Neurology Department, University Hospital of Zurich, Zürich, Switzerland
| | - Marina Herwerth
- Institute of Pharmacology and Toxicology, University of Zurich, Zürich, Switzerland
- Neuroscience Center Zurich (ZNZ), University of Zurich and ETH Zurich, Zürich, Switzerland
- Neurology Department, University Hospital of Zurich, Zürich, Switzerland
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2
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Nayeri T, Sarvi S, Daryani A. Effective factors in the pathogenesis of Toxoplasmagondii. Heliyon 2024; 10:e31558. [PMID: 38818168 PMCID: PMC11137575 DOI: 10.1016/j.heliyon.2024.e31558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Revised: 05/11/2024] [Accepted: 05/17/2024] [Indexed: 06/01/2024] Open
Abstract
Toxoplasma gondii (T. gondii) is a cosmopolitan protozoan parasite in humans and animals. It infects about 30 % of the human population worldwide and causes potentially fatal diseases in immunocompromised hosts and neonates. For this study, five English-language databases (ScienceDirect, ProQuest, Web of Science, PubMed, and Scopus) and the internet search engine Google Scholar were searched. This review was accomplished to draw a global perspective of what is known about the pathogenesis of T. gondii and various factors affecting it. Virulence and immune responses can influence the mechanisms of parasite pathogenesis and these factors are in turn influenced by other factors. In addition to the host's genetic background, the type of Toxoplasma strain, the routes of transmission of infection, the number of passages, and different phases of parasite life affect virulence. The identification of virulence factors of the parasite could provide promising insights into the pathogenesis of this parasite. The results of this study can be an incentive to conduct more intensive research to design and develop new anti-Toxoplasma agents (drugs and vaccines) to treat or prevent this infection. In addition, further studies are needed to better understand the key agents in the pathogenesis of T. gondii.
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Affiliation(s)
- Tooran Nayeri
- Infectious and Tropical Diseases Research Center, Dezful University of Medical Sciences, Dezful, Iran
- Student Research Committee, Mazandaran University of Medical Sciences, Sari, Iran
| | - Shahabeddin Sarvi
- Department of Parasitology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran
| | - Ahmad Daryani
- Department of Parasitology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran
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3
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Moliner-Cubel S, Bahamontes-Rosa N, Rodriguez-Alejandre A, Nassau PM, Argyrou A, Bhardwaja A, Buxton RC, Calvo-Vicente D, Mouzon B, McDowell W, Mendoza-Losana A, Gomez-Lorenzo MG. Plasmodium RNA triphosphatase validation as antimalarial target. Int J Parasitol Drugs Drug Resist 2024; 25:100537. [PMID: 38810336 PMCID: PMC11157219 DOI: 10.1016/j.ijpddr.2024.100537] [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: 06/29/2023] [Revised: 02/23/2024] [Accepted: 04/04/2024] [Indexed: 05/31/2024]
Abstract
Target-based approaches have traditionally been used in the search for new anti-infective molecules. Target selection process, a critical step in Drug Discovery, identifies targets that are essential to establish or maintain the infection, tractable to be susceptible for inhibition, selective towards their human ortholog and amenable for large scale purification and high throughput screening. The work presented herein validates the Plasmodium falciparum mRNA 5' triphosphatase (PfPRT1), the first enzymatic step to cap parasite nuclear mRNAs, as a candidate target for the development of new antimalarial compounds. mRNA capping is essential to maintain the integrity and stability of the messengers, allowing their translation. PfPRT1 has been identified as a member of the tunnel, metal dependent mRNA 5' triphosphatase family which differs structurally and mechanistically from human metal independent mRNA 5' triphosphatase. In the present study the essentiality of PfPRT1 was confirmed and molecular biology tools and methods for target purification, enzymatic assessment and target engagement were developed, with the goal of running a future high throughput screening to discover PfPRT1 inhibitors.
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Affiliation(s)
- Sonia Moliner-Cubel
- Diseases of the Developing World, GlaxoSmithKline, Severo Ochoa 2, 28760, Tres Cantos, Madrid, Spain
| | - Noemi Bahamontes-Rosa
- Diseases of the Developing World, GlaxoSmithKline, Severo Ochoa 2, 28760, Tres Cantos, Madrid, Spain
| | - Ane Rodriguez-Alejandre
- Diseases of the Developing World, GlaxoSmithKline, Severo Ochoa 2, 28760, Tres Cantos, Madrid, Spain
| | - Pamela M Nassau
- Department of Biological Sciences, GlaxoSmithKline, Stevenage, SG2 7NY, UK
| | - Argyrides Argyrou
- Department of Biological Sciences, GlaxoSmithKline, Stevenage, SG2 7NY, UK
| | - Anshu Bhardwaja
- Department of Biological Sciences, GlaxoSmithKline, Stevenage, SG2 7NY, UK
| | - Rachel C Buxton
- Department of Biological Sciences, GlaxoSmithKline, Stevenage, SG2 7NY, UK
| | - David Calvo-Vicente
- Diseases of the Developing World, GlaxoSmithKline, Severo Ochoa 2, 28760, Tres Cantos, Madrid, Spain
| | - Bernadette Mouzon
- Department of Biological Sciences, GlaxoSmithKline, Stevenage, SG2 7NY, UK
| | - William McDowell
- Department of Biological Sciences, GlaxoSmithKline, Stevenage, SG2 7NY, UK
| | - Alfonso Mendoza-Losana
- Diseases of the Developing World, GlaxoSmithKline, Severo Ochoa 2, 28760, Tres Cantos, Madrid, Spain
| | - Maria G Gomez-Lorenzo
- Diseases of the Developing World, GlaxoSmithKline, Severo Ochoa 2, 28760, Tres Cantos, Madrid, Spain.
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4
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Gupta S, Saini M, Joshi N, Shafi S, Najmi AK, Singh S. Antimalarial and Plasmodium falciparum serpentine receptor 12 targeting effect of FDA approved purinergic receptor antagonist. J Biomol Struct Dyn 2023; 41:9462-9475. [PMID: 36351236 DOI: 10.1080/07391102.2022.2142298] [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: 07/11/2022] [Accepted: 10/26/2022] [Indexed: 11/11/2022]
Abstract
Intraerythrocytic stages of Plasmodium falciparum responsible for all clinical manifestations of malaria are regulated by array of signalling cascades that represent attractive targets for antimalarial therapy. G-protein coupled receptors (GPCRs) are druggable targets in the treatment of various pathological conditions, however, there is limited understanding about the role of GPCRs in malaria pathogenesis. In Plasmodium, serpentine receptors (PfSR1, PfSR10, PfSR12 and PfSR25) with GPCR-like membrane topology have been reported with the finite knowledge about their potential as antimalarial targets. We analyzed the localization of these receptors in malaria parasite by immunofluorescence assays. All four receptors were expressed in blood stages with PfSR12 expressing more in late intraerythrocytic stages. Further, we evaluated the druggability of PfSR12 using FDA-approved P2Y purinergic receptor antagonist, Prasugrel and its active metabolite R138727, which is proposed to be specific towards PfSR12. Interestingly, biophysical analysis indicated strong binding between PfSR12 and R138727 as compared to the prodrug Prasugrel. This binding interaction was further confirmed by thermal shift assay. Treatment of parasite with Prasugrel and R138727 resulted in growth inhibition of P. falciparum indicating an important role of purinergic signalling and PfSR12 in parasite survival. Next, progression studies indicated the inhibitory effect of Prasugrel begins in late erythrocyte stages corroborating with PfSR12 expression at these stages. Furthermore, Prasugrel also blocked in vivo growth of malaria parasite in a mouse experimental model. This study indicates the presence of P2Y type of purinergic signalling in growth and development of malaria parasite and suggests PfSR12, putative purinergic receptor druggability through Prasugrel.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Sonal Gupta
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, India
| | - Monika Saini
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, India
- Department of Life Sciences, Shiv Nadar University, Gautam Buddha Nagar, India
| | - Nishant Joshi
- Department of Life Sciences, Shiv Nadar University, Gautam Buddha Nagar, India
| | - Sadat Shafi
- Department of Pharmacology, School of Pharmaceutical Education and Research, Jamia Hamdard University, New Delhi, India
| | - Abul Kalam Najmi
- Department of Pharmacology, School of Pharmaceutical Education and Research, Jamia Hamdard University, New Delhi, India
| | - Shailja Singh
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, India
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5
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Makarov A, Began J, Mautone IC, Pinto E, Ferguson L, Zoltner M, Zoll S, Field MC. The role of invariant surface glycoprotein 75 in xenobiotic acquisition by African trypanosomes. MICROBIAL CELL (GRAZ, AUSTRIA) 2023; 10:18-35. [PMID: 36789350 PMCID: PMC9896412 DOI: 10.15698/mic2023.02.790] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 01/02/2023] [Accepted: 01/13/2023] [Indexed: 02/05/2023]
Abstract
The surface proteins of parasitic protozoa mediate functions essential to survival within a host, including nutrient accumulation, environmental sensing and immune evasion. Several receptors involved in nutrient uptake and defence from the innate immune response have been described in African trypanosomes and, together with antigenic variation, contribute towards persistence within vertebrate hosts. Significantly, a superfamily of invariant surface glycoproteins (ISGs) populates the trypanosome surface, one of which, ISG75, is implicated in uptake of the century-old drug suramin. By CRISPR/Cas9 knockout and biophysical analysis, we show here that ISG75 directly binds suramin and mediates uptake of additional naphthol-related compounds, making ISG75 a conduit for entry of at least one structural class of trypanocidal compounds. However, ISG75 null cells present only modest attenuation of suramin sensitivity, have unaltered viability in vivo and in vitro and no alteration to suramin-invoked proteome responses. While ISG75 is demonstrated as a valid suramin cell entry pathway, we suggest the presence of additional mechanisms for suramin accumulation, further demonstrating the complexity of trypanosomatid drug interactions and potential for evolution of resistance.
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Affiliation(s)
- Alexandr Makarov
- School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
| | - Jakub Began
- Laboratory of Structural Parasitology, Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, 16610 Prague 6, Czech Republic
| | - Ileana Corvo Mautone
- School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
- Laboratorio de Moléculas Bioactivas, Departamento de Ciencias Biológicas, Universidad de la República, Paysandú 60000, Uruguay
| | - Erika Pinto
- School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
| | - Liam Ferguson
- School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
| | - Martin Zoltner
- School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
- Charles University, Faculty of Science, Department of Parasitology, Vestec, Czech Republic
| | - Sebastian Zoll
- Laboratory of Structural Parasitology, Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, 16610 Prague 6, Czech Republic
| | - Mark C. Field
- School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, 37005 Ceske Budejovice, Czech Republic
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6
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Dey D, Ramakumar S, Conn GL. Targeted Redesign of Suramin Analogs for Novel Antimicrobial Lead Development. J Chem Inf Model 2021; 61:4442-4454. [PMID: 34516120 DOI: 10.1021/acs.jcim.1c00578] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The emergence of new viral infections and drug-resistant bacteria urgently necessitates expedient therapeutic development. Repurposing and redesign of existing drugs against different targets are one potential way in which to accelerate this process. Suramin was initially developed as a successful antiparasitic drug but has also shown promising antiviral and antibacterial activities. However, due to its high conformational flexibility and negative charge, suramin is considered quite promiscuous toward positively charged sites within nucleic acid binding proteins. Although some suramin analogs have been developed against specific targets, only limited structure-activity relationship studies were performed, and virtual screening has yet to be used to identify more specific inhibitor(s) based on its scaffold. Using available structures, we investigated suramin's target diversity, confirming that suramin preferentially binds to protein pockets that are both positively charged and enriched in aromatic or leucine residues. Further, suramin's high conformational flexibility allows adaptation to structurally diverse binding surfaces. From this platform, we developed a framework for structure- and docking-guided elaboration of suramin analog scaffolds using virtual screening of suramin and heparin analogs against a panel of diverse therapeutically relevant viral and bacterial protein targets. Use of this new framework to design potentially specific suramin analogs is exemplified using the SARS-CoV-2 RNA-dependent RNA polymerase and nucleocapsid protein, identifying leads that might inhibit a wide range of coronaviruses. The approach presented here establishes a computational framework for designing suramin analogs against different bacterial and viral targets and repurposing existing drugs for more specific inhibitory activity.
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Affiliation(s)
- Debayan Dey
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia 30322, United States
| | | | - Graeme L Conn
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia 30322, United States.,Emory Antibiotic Resistance Center (ARC), Emory University, Atlanta, Georgia 30322, United States
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7
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Repurposing Drugs to Fight Hepatic Malaria Parasites. Molecules 2020; 25:molecules25153409. [PMID: 32731386 PMCID: PMC7435416 DOI: 10.3390/molecules25153409] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 07/23/2020] [Accepted: 07/24/2020] [Indexed: 12/16/2022] Open
Abstract
Malaria remains one of the most prevalent infectious diseases worldwide, primarily affecting some of the most vulnerable populations around the globe. Despite achievements in the treatment of this devastating disease, there is still an urgent need for the discovery of new drugs that tackle infection by Plasmodium parasites. However, de novo drug development is a costly and time-consuming process. An alternative strategy is to evaluate the anti-plasmodial activity of compounds that are already approved for other purposes, an approach known as drug repurposing. Here, we will review efforts to assess the anti-plasmodial activity of existing drugs, with an emphasis on the obligatory and clinically silent liver stage of infection. We will also review the current knowledge on the classes of compounds that might be therapeutically relevant against Plasmodium in the context of other communicable diseases that are prevalent in regions where malaria is endemic. Repositioning existing compounds may constitute a faster solution to the current gap of prophylactic and therapeutic drugs that act on Plasmodium parasites, overall contributing to the global effort of malaria eradication.
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8
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Abstract
Suramin is 100 years old and is still being used to treat the first stage of acute human sleeping sickness, caused by Trypanosoma brucei rhodesiense Suramin is a multifunctional molecule with a wide array of potential applications, from parasitic and viral diseases to cancer, snakebite, and autism. Suramin is also an enigmatic molecule: What are its targets? How does it get into cells in the first place? Here, we provide an overview of the many different candidate targets of suramin and discuss its modes of action and routes of cellular uptake. We reason that, once the polypharmacology of suramin is understood at the molecular level, new, more specific, and less toxic molecules can be identified for the numerous potential applications of suramin.
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9
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Burns AL, Dans MG, Balbin JM, de Koning-Ward TF, Gilson PR, Beeson JG, Boyle MJ, Wilson DW. Targeting malaria parasite invasion of red blood cells as an antimalarial strategy. FEMS Microbiol Rev 2019; 43:223-238. [PMID: 30753425 PMCID: PMC6524681 DOI: 10.1093/femsre/fuz005] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2018] [Accepted: 02/11/2019] [Indexed: 12/20/2022] Open
Abstract
Plasmodium spp. parasites that cause malaria disease remain a significant global-health burden. With the spread of parasites resistant to artemisinin combination therapies in Southeast Asia, there is a growing need to develop new antimalarials with novel targets. Invasion of the red blood cell by Plasmodium merozoites is essential for parasite survival and proliferation, thus representing an attractive target for therapeutic development. Red blood cell invasion requires a co-ordinated series of protein/protein interactions, protease cleavage events, intracellular signals, organelle release and engagement of an actin-myosin motor, which provide many potential targets for drug development. As these steps occur in the bloodstream, they are directly susceptible and exposed to drugs. A number of invasion inhibitors against a diverse range of parasite proteins involved in these different processes of invasion have been identified, with several showing potential to be optimised for improved drug-like properties. In this review, we discuss red blood cell invasion as a drug target and highlight a number of approaches for developing antimalarials with invasion inhibitory activity to use in future combination therapies.
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Affiliation(s)
- Amy L Burns
- Research Centre for Infectious Diseases, School of Biological Sciences, University of Adelaide, Adelaide, Australia 5005
| | - Madeline G Dans
- Burnet Institute, Melbourne, Victoria, Australia 3004.,Deakin University, School of Medicine, Waurn Ponds, Victoria, Australia 3216
| | - Juan M Balbin
- Research Centre for Infectious Diseases, School of Biological Sciences, University of Adelaide, Adelaide, Australia 5005
| | | | - Paul R Gilson
- Burnet Institute, Melbourne, Victoria, Australia 3004
| | - James G Beeson
- Burnet Institute, Melbourne, Victoria, Australia 3004.,Central Clinical School and Department of Microbiology, Monash University 3004.,Department of Medicine, University of Melbourne, Australia 3052
| | - Michelle J Boyle
- Burnet Institute, Melbourne, Victoria, Australia 3004.,QIMR Berghofer Medical Research Institute, Herston, Queensland, Australia 4006
| | - Danny W Wilson
- Research Centre for Infectious Diseases, School of Biological Sciences, University of Adelaide, Adelaide, Australia 5005.,Burnet Institute, Melbourne, Victoria, Australia 3004
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10
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Quemé‐Peña M, Juhász T, Mihály J, Cs. Szigyártó I, Horváti K, Bősze S, Henczkó J, Pályi B, Németh C, Varga Z, Zsila F, Beke‐Somfai T. Manipulating Active Structure and Function of Cationic Antimicrobial Peptide CM15 with the Polysulfonated Drug Suramin: A Step Closer to in Vivo Complexity. Chembiochem 2019; 20:1578-1590. [PMID: 30720915 PMCID: PMC6618317 DOI: 10.1002/cbic.201800801] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Indexed: 12/11/2022]
Abstract
Antimicrobial peptides (AMPs) kill bacteria by targeting their membranes through various mechanisms involving peptide assembly, often coupled with disorder-to-order structural transition. However, for several AMPs, similar conformational changes in cases in which small organic compounds of both endogenous and exogenous origin have induced folded peptide conformations have recently been reported. Thus, the function of AMPs and of natural host defence peptides can be significantly affected by the local complex molecular environment in vivo; nonetheless, this area is hardly explored. To address the relevance of such interactions with regard to structure and function, we have tested the effects of the therapeutic drug suramin on the membrane activity and antibacterial efficiency of CM15, a potent hybrid AMP. The results provided insight into a dynamic system in which peptide interaction with lipid bilayers is interfered with by the competitive binding of CM15 to suramin, resulting in an equilibrium dependent on peptide-to-drug ratio and vesicle surface charge. In vitro bacterial tests showed that when CM15⋅suramin complex formation dominates over membrane binding, antimicrobial activity is abolished. On the basis of this case study, it is proposed that small-molecule secondary structure regulators can modify AMP function and that this should be considered and could potentially be exploited in future development of AMP-based antimicrobial agents.
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Affiliation(s)
- Mayra Quemé‐Peña
- Institute of Materials and Environmental ChemistryResearch Centre for Natural SciencesHungarian Academy of SciencesMagyar tudósok körútja 21117BudapestHungary
| | - Tünde Juhász
- Institute of Materials and Environmental ChemistryResearch Centre for Natural SciencesHungarian Academy of SciencesMagyar tudósok körútja 21117BudapestHungary
| | - Judith Mihály
- Institute of Materials and Environmental ChemistryResearch Centre for Natural SciencesHungarian Academy of SciencesMagyar tudósok körútja 21117BudapestHungary
| | - Imola Cs. Szigyártó
- Institute of Materials and Environmental ChemistryResearch Centre for Natural SciencesHungarian Academy of SciencesMagyar tudósok körútja 21117BudapestHungary
| | - Kata Horváti
- MTA-ELTE Research Group of Peptide ChemistryHungarian Academy of SciencesEötvös Loránd UniversityPázmány Péter sétány 1/A1117BudapestHungary
| | - Szilvia Bősze
- MTA-ELTE Research Group of Peptide ChemistryHungarian Academy of SciencesEötvös Loránd UniversityPázmány Péter sétány 1/A1117BudapestHungary
| | - Judit Henczkó
- National Biosafety LaboratoryNational Public Health CenterAlbert Flórián út 21097BudapestHungary
| | - Bernadett Pályi
- National Biosafety LaboratoryNational Public Health CenterAlbert Flórián út 21097BudapestHungary
| | - Csaba Németh
- Institute of Materials and Environmental ChemistryResearch Centre for Natural SciencesHungarian Academy of SciencesMagyar tudósok körútja 21117BudapestHungary
| | - Zoltán Varga
- Institute of Materials and Environmental ChemistryResearch Centre for Natural SciencesHungarian Academy of SciencesMagyar tudósok körútja 21117BudapestHungary
| | - Ferenc Zsila
- Institute of Materials and Environmental ChemistryResearch Centre for Natural SciencesHungarian Academy of SciencesMagyar tudósok körútja 21117BudapestHungary
| | - Tamás Beke‐Somfai
- Institute of Materials and Environmental ChemistryResearch Centre for Natural SciencesHungarian Academy of SciencesMagyar tudósok körútja 21117BudapestHungary
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11
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Peinado RDS, Olivier DS, Eberle RJ, de Moraes FR, Amaral MS, Arni RK, Coronado MA. Binding studies of a putative C. pseudotuberculosis target protein from Vitamin B 12 Metabolism. Sci Rep 2019; 9:6350. [PMID: 31015525 PMCID: PMC6478909 DOI: 10.1038/s41598-019-42935-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 03/13/2019] [Indexed: 01/20/2023] Open
Abstract
Vitamin B12 acts as a cofactor for various metabolic reactions important in living organisms. The Vitamin B12 biosynthesis is restricted to prokaryotes, which means, all eukaryotic organisms must acquire this molecule through diet. This study presents the investigation of Vitamin B12 metabolism and the characterization of precorrin-4 C(11)-methyltransferase (CobM), an enzyme involved in the biosynthesis of Vitamin B12 in Corynebacterium pseudotuberculosis. The analysis of the C. pseudotuberculosis genome identified two Vitamin B12-dependent pathways, which can be strongly affected by a disrupted vitamin metabolism. Molecular dynamics, circular dichroism, and NMR-STD experiments identified regions in CobM that undergo conformational changes after s-adenosyl-L-methionine binding to promote the interaction of precorrin-4, a Vitamin B12 precursor. The binding of s-adenosyl-L-methionine was examined along with the competitive binding of adenine, dATP, and suramin. Based on fluorescence spectroscopy experiments the dissociation constant for the four ligands and the target protein could be determined; SAM (1.4 ± 0.7 µM), adenine (17.8 ± 1.5 µM), dATP (15.8 ± 2.0 µM), and Suramin (6.3 ± 1.1 µM). The results provide rich information for future investigations of potential drug targets within the C. pseudotuberculosis's Vitamin B12 metabolism and related pathways to reduce the pathogen's virulence in its hosts.
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Affiliation(s)
- Rafaela Dos S Peinado
- Multiuser Center for Biomolecular Innovation, Departament of Physics, Instituto de Biociências Letras e Ciências Exatas (Ibilce), Universidade Estadual Paulista (UNESP), São Jose do Rio Preto-SP, 15054-000, Brazil
| | - Danilo S Olivier
- Multiuser Center for Biomolecular Innovation, Departament of Physics, Instituto de Biociências Letras e Ciências Exatas (Ibilce), Universidade Estadual Paulista (UNESP), São Jose do Rio Preto-SP, 15054-000, Brazil
| | - Raphael J Eberle
- Multiuser Center for Biomolecular Innovation, Departament of Physics, Instituto de Biociências Letras e Ciências Exatas (Ibilce), Universidade Estadual Paulista (UNESP), São Jose do Rio Preto-SP, 15054-000, Brazil
| | - Fabio R de Moraes
- Multiuser Center for Biomolecular Innovation, Departament of Physics, Instituto de Biociências Letras e Ciências Exatas (Ibilce), Universidade Estadual Paulista (UNESP), São Jose do Rio Preto-SP, 15054-000, Brazil
| | - Marcos S Amaral
- Institute of Physics, Federal University of Mato Grosso do Sul, Campo Grande, MS, 79090-700, Brazil
| | - Raghuvir K Arni
- Multiuser Center for Biomolecular Innovation, Departament of Physics, Instituto de Biociências Letras e Ciências Exatas (Ibilce), Universidade Estadual Paulista (UNESP), São Jose do Rio Preto-SP, 15054-000, Brazil.
| | - Monika A Coronado
- Multiuser Center for Biomolecular Innovation, Departament of Physics, Instituto de Biociências Letras e Ciências Exatas (Ibilce), Universidade Estadual Paulista (UNESP), São Jose do Rio Preto-SP, 15054-000, Brazil.
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12
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Lauri N, Bazzi Z, Alvarez CL, Leal Denis MF, Schachter J, Herlax V, Ostuni MA, Schwarzbaum PJ. ATPe Dynamics in Protozoan Parasites. Adapt or Perish. Genes (Basel) 2018; 10:E16. [PMID: 30591699 PMCID: PMC6356682 DOI: 10.3390/genes10010016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Revised: 12/18/2018] [Accepted: 12/19/2018] [Indexed: 01/25/2023] Open
Abstract
In most animals, transient increases of extracellular ATP (ATPe) are used for physiological signaling or as a danger signal in pathological conditions. ATPe dynamics are controlled by ATP release from viable cells and cell lysis, ATPe degradation and interconversion by ecto-nucleotidases, and interaction of ATPe and byproducts with cell surface purinergic receptors and purine salvage mechanisms. Infection by protozoan parasites may alter at least one of the mechanisms controlling ATPe concentration. Protozoan parasites display their own set of proteins directly altering ATPe dynamics, or control the activity of host proteins. Parasite dependent activation of ATPe conduits of the host may promote infection and systemic responses that are beneficial or detrimental to the parasite. For instance, activation of organic solute permeability at the host membrane can support the elevated metabolism of the parasite. On the other hand ecto-nucleotidases of protozoan parasites, by promoting ATPe degradation and purine/pyrimidine salvage, may be involved in parasite growth, infectivity, and virulence. In this review, we will describe the complex dynamics of ATPe regulation in the context of protozoan parasite⁻host interactions. Particular focus will be given to features of parasite membrane proteins strongly controlling ATPe dynamics. This includes evolutionary, genetic and cellular mechanisms, as well as structural-functional relationships.
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Affiliation(s)
- Natalia Lauri
- Institute of Biological Chemistry and Physicochemistry (IQUIFIB) "Prof. Alejandro C. Paladini", Faculty of Pharmacy and Biochemistry, University of Buenos Aires, National Scientific and Technical Research Council (CONICET), Junín 956 Buenos Aires, Argentina.
- Faculty of Pharmacy and Biochemistry, Department of Biological Chemistry, Chair of Biological Chemistry, University of Buenos Aires, Junín 956 Buenos Aires, Argentina.
| | - Zaher Bazzi
- Institute of Biological Chemistry and Physicochemistry (IQUIFIB) "Prof. Alejandro C. Paladini", Faculty of Pharmacy and Biochemistry, University of Buenos Aires, National Scientific and Technical Research Council (CONICET), Junín 956 Buenos Aires, Argentina.
| | - Cora L Alvarez
- Institute of Biological Chemistry and Physicochemistry (IQUIFIB) "Prof. Alejandro C. Paladini", Faculty of Pharmacy and Biochemistry, University of Buenos Aires, National Scientific and Technical Research Council (CONICET), Junín 956 Buenos Aires, Argentina.
- Faculty of Exact and Natural Sciences, Department of Biodiversity and Experimental Biology, University of Buenos Aires, Intendente Güiraldes, Buenos Aires 2160, Argentina.
| | - María F Leal Denis
- Institute of Biological Chemistry and Physicochemistry (IQUIFIB) "Prof. Alejandro C. Paladini", Faculty of Pharmacy and Biochemistry, University of Buenos Aires, National Scientific and Technical Research Council (CONICET), Junín 956 Buenos Aires, Argentina.
- Chair of Analytical Chemistry and Physicochemistry, Faculty of Pharmacy and Biochemistry, Department of Analytical Chemistry, University of Buenos Aires, Junín 956 Buenos Aires, Argentina.
| | - Julieta Schachter
- Institute of Biological Chemistry and Physicochemistry (IQUIFIB) "Prof. Alejandro C. Paladini", Faculty of Pharmacy and Biochemistry, University of Buenos Aires, National Scientific and Technical Research Council (CONICET), Junín 956 Buenos Aires, Argentina.
| | - Vanesa Herlax
- Biochemistry Research Institute of La Plata (INIBIOLP) "Prof. Dr. Rodolfo R. Brenner", Faculty of Medical Sciences, National University of La Plata, National Scientific and Technical Research Council, Av. 60 y Av. 120 La Plata, Argentina.
- National University of La Plata, Faculty of Medical Sciences, Av. 60 y Av. 120 La Plata, Argentina.
| | - Mariano A Ostuni
- UMR-S1134, Integrated Biology of Red Blood Cells, INSERM, Paris Diderot University, Sorbonne Paris Cité, University of La Réunion, University of Antilles, F-75015 Paris, France.
- National Institute of Blood Transfusion (INTS), Laboratory of Excellence GR-Ex, F-75015 Paris, France.
| | - Pablo J Schwarzbaum
- Institute of Biological Chemistry and Physicochemistry (IQUIFIB) "Prof. Alejandro C. Paladini", Faculty of Pharmacy and Biochemistry, University of Buenos Aires, National Scientific and Technical Research Council (CONICET), Junín 956 Buenos Aires, Argentina.
- Faculty of Pharmacy and Biochemistry, Department of Biological Chemistry, Chair of Biological Chemistry, University of Buenos Aires, Junín 956 Buenos Aires, Argentina.
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13
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Armistead JS, Jennison C, O'Neill MT, Lopaticki S, Liehl P, Hanson KK, Annoura T, Rajasekaran P, Erickson SM, Tonkin CJ, Khan SM, Mota MM, Boddey JA. Plasmodium falciparum
subtilisin-like ookinete protein SOPT plays an important and conserved role during ookinete infection of the Anopheles stephensi
midgut. Mol Microbiol 2018; 109:458-473. [DOI: 10.1111/mmi.13993] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/22/2018] [Indexed: 11/27/2022]
Affiliation(s)
- Jennifer S. Armistead
- The Walter and Eliza Hall Institute of Medical Research; Parkville 3052 Australia
- Department of Medical Biology; The University of Melbourne; Parkville 3052 Australia
| | - Charlie Jennison
- The Walter and Eliza Hall Institute of Medical Research; Parkville 3052 Australia
- Department of Medical Biology; The University of Melbourne; Parkville 3052 Australia
| | - Matthew T. O'Neill
- The Walter and Eliza Hall Institute of Medical Research; Parkville 3052 Australia
| | - Sash Lopaticki
- The Walter and Eliza Hall Institute of Medical Research; Parkville 3052 Australia
| | - Peter Liehl
- Instituto de Medicina Molecular, Faculdade de Medicina; Universidade de Lisboa; 1649-028 Lisbon Portugal
| | - Kirsten K. Hanson
- Instituto de Medicina Molecular, Faculdade de Medicina; Universidade de Lisboa; 1649-028 Lisbon Portugal
| | - Takeshi Annoura
- Leiden Malaria Research Group, Parasitology; Leiden University Medical Centre; 2333ZA Leiden the Netherlands
| | - Pravin Rajasekaran
- The Walter and Eliza Hall Institute of Medical Research; Parkville 3052 Australia
- Department of Medical Biology; The University of Melbourne; Parkville 3052 Australia
| | - Sara M. Erickson
- The Walter and Eliza Hall Institute of Medical Research; Parkville 3052 Australia
- Department of Medical Biology; The University of Melbourne; Parkville 3052 Australia
| | - Christopher J. Tonkin
- The Walter and Eliza Hall Institute of Medical Research; Parkville 3052 Australia
- Department of Medical Biology; The University of Melbourne; Parkville 3052 Australia
| | - Shahid M. Khan
- Leiden Malaria Research Group, Parasitology; Leiden University Medical Centre; 2333ZA Leiden the Netherlands
| | - Maria M. Mota
- Instituto de Medicina Molecular, Faculdade de Medicina; Universidade de Lisboa; 1649-028 Lisbon Portugal
| | - Justin A. Boddey
- The Walter and Eliza Hall Institute of Medical Research; Parkville 3052 Australia
- Department of Medical Biology; The University of Melbourne; Parkville 3052 Australia
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14
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Quintana MDP, Ch’ng JH, Zandian A, Imam M, Hultenby K, Theisen M, Nilsson P, Qundos U, Moll K, Chan S, Wahlgren M. SURGE complex of Plasmodium falciparum in the rhoptry-neck (SURFIN4.2-RON4-GLURP) contributes to merozoite invasion. PLoS One 2018; 13:e0201669. [PMID: 30092030 PMCID: PMC6084945 DOI: 10.1371/journal.pone.0201669] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Accepted: 07/19/2018] [Indexed: 12/25/2022] Open
Abstract
Plasmodium falciparum invasion into red blood cells (RBCs) is a complex process engaging proteins on the merozoite surface and those contained and sequentially released from the apical organelles (micronemes and rhoptries). Fundamental to invasion is the formation of a moving junction (MJ), a region of close apposition of the merozoite and the RBC plasma membranes, through which the merozoite draws itself before settling into a newly formed parasitophorous vacuole (PV). SURFIN4.2 was identified at the surface of the parasitized RBCs (pRBCs) but was also found apically associated with the merozoite. Using antibodies against the N-terminus of the protein we show the presence of SURFIN4.2 in the neck of the rhoptries, its secretion into the PV and shedding into the culture supernatant upon schizont rupture. Using immunoprecipitation followed by mass spectrometry we describe here a novel protein complex we have named SURGE where SURFIN4.2 forms interacts with the rhoptry neck protein 4 (RON4) and the Glutamate Rich Protein (GLURP). The N-terminal cysteine-rich-domain (CRD) of SURFIN4.2 mediates binding to the RBC membrane and its interaction with RON4 suggests its involvement in the contact between the merozoite apex and the RBC at the MJ. Supporting this suggestion, we also found that polyclonal antibodies to the extracellular domain (including the CRD) of SURFIN4.2 partially inhibit merozoite invasion. We propose that the formation of the SURGE complex participates in the establishment of parasite infection within the PV and the RBCs.
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Affiliation(s)
- Maria del Pilar Quintana
- Department of Microbiology, Tumor and Cell Biology (MTC), Biomedicum, Karolinska Institutet, Stockholm, Sweden
| | - Jun-Hong Ch’ng
- Department of Microbiology, Tumor and Cell Biology (MTC), Biomedicum, Karolinska Institutet, Stockholm, Sweden
- Department of Microbiology and Immunology, National University of Singapore, Singapore, Singapore
| | - Arash Zandian
- Affinity Proteomics, Science for Life Laboratory, School of Biotechnology, KTH-Royal Institutet of Technology, Stockholm, Sweden
| | - Maryam Imam
- Department of Microbiology, Tumor and Cell Biology (MTC), Biomedicum, Karolinska Institutet, Stockholm, Sweden
| | - Kjell Hultenby
- Division of Clinical Research Centre, Department of Laboratory Medicine, Karolinska Institutet, Huddinge, Sweden
| | - Michael Theisen
- Department for Congenital Disorders, Statens Serum Institut, Copenhagen, Denmark
- Centre for Medical Parasitology, Department of International Health, Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Peter Nilsson
- Affinity Proteomics, Science for Life Laboratory, School of Biotechnology, KTH-Royal Institutet of Technology, Stockholm, Sweden
| | - Ulrika Qundos
- Affinity Proteomics, Science for Life Laboratory, School of Biotechnology, KTH-Royal Institutet of Technology, Stockholm, Sweden
| | - Kirsten Moll
- Department of Microbiology, Tumor and Cell Biology (MTC), Biomedicum, Karolinska Institutet, Stockholm, Sweden
| | - Sherwin Chan
- Department of Microbiology, Tumor and Cell Biology (MTC), Biomedicum, Karolinska Institutet, Stockholm, Sweden
| | - Mats Wahlgren
- Department of Microbiology, Tumor and Cell Biology (MTC), Biomedicum, Karolinska Institutet, Stockholm, Sweden
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15
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Identification of Heparin Modifications and Polysaccharide Inhibitors of Plasmodium falciparum Merozoite Invasion That Have Potential for Novel Drug Development. Antimicrob Agents Chemother 2017; 61:AAC.00709-17. [PMID: 28893781 DOI: 10.1128/aac.00709-17] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Accepted: 09/03/2017] [Indexed: 11/20/2022] Open
Abstract
Despite recent successful control efforts, malaria remains a leading global health burden. Alarmingly, resistance to current antimalarials is increasing and the development of new drug families is needed to maintain malaria control. Current antimalarials target the intraerythrocytic developmental stage of the Plasmodium falciparum life cycle. However, the invasive extracellular parasite form, the merozoite, is also an attractive target for drug development. We have previously demonstrated that heparin-like molecules, including those with low molecular weights and low anticoagulant activities, are potent and specific inhibitors of merozoite invasion and blood-stage replication. Here we tested a large panel of heparin-like molecules and sulfated polysaccharides together with various modified chemical forms for their inhibitory activity against P. falciparum merozoite invasion. We identified chemical modifications that improve inhibitory activity and identified several additional sulfated polysaccharides with strong inhibitory activity. These studies have important implications for the further development of heparin-like molecules as antimalarial drugs and for understanding merozoite invasion.
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16
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Soni R, Sharma D, Rai P, Sharma B, Bhatt TK. Signaling Strategies of Malaria Parasite for Its Survival, Proliferation, and Infection during Erythrocytic Stage. Front Immunol 2017; 8:349. [PMID: 28400771 PMCID: PMC5368685 DOI: 10.3389/fimmu.2017.00349] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 03/10/2017] [Indexed: 12/22/2022] Open
Abstract
Irrespective of various efforts, malaria persist the most debilitating effect in terms of morbidity and mortality. Moreover, the existing drugs are also vulnerable to the emergence of drug resistance. To explore the potential targets for designing the most effective antimalarial therapies, it is required to focus on the facts of biochemical mechanism underlying the process of parasite survival and disease pathogenesis. This review is intended to bring out the existing knowledge about the functions and components of the major signaling pathways such as kinase signaling, calcium signaling, and cyclic nucleotide-based signaling, serving the various aspects of the parasitic asexual stage and highlighted the Toll-like receptors, glycosylphosphatidylinositol-mediated signaling, and molecular events in cytoadhesion, which elicit the host immune response. This discussion will facilitate a look over essential components for parasite survival and disease progression to be implemented in discovery of novel antimalarial drugs and vaccines.
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Affiliation(s)
- Rani Soni
- Department of Biotechnology, School of Life sciences, Central University of Rajasthan , Ajmer , India
| | - Drista Sharma
- Department of Biotechnology, School of Life sciences, Central University of Rajasthan , Ajmer , India
| | - Praveen Rai
- Department of Biotechnology, School of Life sciences, Central University of Rajasthan , Ajmer , India
| | - Bhaskar Sharma
- Department of Biotechnology, School of Life sciences, Central University of Rajasthan , Ajmer , India
| | - Tarun K Bhatt
- Department of Biotechnology, School of Life sciences, Central University of Rajasthan , Ajmer , India
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17
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Borges-Pereira L, Meissner KA, Wrenger C, Garcia CRS. Plasmodium falciparum GFP-E-NTPDase expression at the intraerythrocytic stages and its inhibition blocks the development of the human malaria parasite. Purinergic Signal 2017; 13:267-277. [PMID: 28285440 PMCID: PMC5563288 DOI: 10.1007/s11302-017-9557-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Accepted: 02/06/2017] [Indexed: 12/17/2022] Open
Abstract
Plasmodium falciparum is the causative agent of the most dangerous form of malaria in humans. It has been reported that the P. falciparum genome encodes for a single ecto-nucleoside triphosphate diphosphohydrolase (E-NTPDase), an enzyme that hydrolyzes extracellular tri- and di-phosphate nucleotides. The E-NTPDases are known for participating in invasion and as a virulence factor in many pathogenic protozoa. Despite its presence in the parasite genome, currently, no information exists about the activity of this predicted protein. Here, we show for the first time that P. falciparum E-NTPDase is relevant for parasite lifecycle as inhibition of this enzyme impairs the development of P. falciparum within red blood cells (RBCs). ATPase activity could be detected in rings, trophozoites, and schizonts, as well as qRT-PCR, confirming that E-NTPDase is expressed throughout the intraerythrocytic cycle. In addition, transfection of a construct which expresses approximately the first 500 bp of an E-NTPDase-GFP chimera shows that E-NTPDase co-localizes with the endoplasmic reticulum (ER) in the early stages and with the digestive vacuole (DV) in the late stages of P. falciparum intraerythrocytic cycle.
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Affiliation(s)
- Lucas Borges-Pereira
- Departamento de Parasitologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil.,Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, Rua do Matão 101, travessa 14, São Paulo, SP, 05508-090, Brazil
| | - Kamila Anna Meissner
- Departamento de Parasitologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
| | - Carsten Wrenger
- Departamento de Parasitologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
| | - Célia R S Garcia
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, Rua do Matão 101, travessa 14, São Paulo, SP, 05508-090, Brazil.
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18
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Structural and functional attributes of malaria parasite diadenosine tetraphosphate hydrolase. Sci Rep 2016; 6:19981. [PMID: 26829485 PMCID: PMC4734340 DOI: 10.1038/srep19981] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 12/15/2015] [Indexed: 11/09/2022] Open
Abstract
Malaria symptoms are driven by periodic multiplication cycles of Plasmodium parasites in human red blood corpuscles (RBCs). Malaria infection still accounts for ~600,000 annual deaths, and hence discovery of both new drug targets and drugs remains vital. In the present study, we have investigated the malaria parasite enzyme diadenosine tetraphosphate (Ap4A) hydrolase that regulates levels of signalling molecules like Ap4A by hydrolyzing them to ATP and AMP. We have tracked the spatial distribution of parasitic Ap4A hydrolase in infected RBCs, and reveal its unusual localization on the infected RBC membrane in subpopulation of infected cells. Interestingly, enzyme activity assays reveal an interaction between Ap4A hydrolase and the parasite growth inhibitor suramin. We also present a high resolution crystal structure of Ap4A hydrolase in apo- and sulphate- bound state, where the sulphate resides in the enzyme active site by mimicking the phosphate of substrates like Ap4A. The unexpected infected erythrocyte localization of the parasitic Ap4A hydrolase hints at a possible role of this enzyme in purinerigic signaling. In addition, atomic structure of Ap4A hydrolase provides insights for selective drug targeting.
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19
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Beeson JG, Drew DR, Boyle MJ, Feng G, Fowkes FJI, Richards JS. Merozoite surface proteins in red blood cell invasion, immunity and vaccines against malaria. FEMS Microbiol Rev 2016; 40:343-72. [PMID: 26833236 PMCID: PMC4852283 DOI: 10.1093/femsre/fuw001] [Citation(s) in RCA: 218] [Impact Index Per Article: 27.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/03/2016] [Indexed: 01/11/2023] Open
Abstract
Malaria accounts for an enormous burden of disease globally, with Plasmodium falciparum accounting for the majority of malaria, and P. vivax being a second important cause, especially in Asia, the Americas and the Pacific. During infection with Plasmodium spp., the merozoite form of the parasite invades red blood cells and replicates inside them. It is during the blood-stage of infection that malaria disease occurs and, therefore, understanding merozoite invasion, host immune responses to merozoite surface antigens, and targeting merozoite surface proteins and invasion ligands by novel vaccines and therapeutics have been important areas of research. Merozoite invasion involves multiple interactions and events, and substantial processing of merozoite surface proteins occurs before, during and after invasion. The merozoite surface is highly complex, presenting a multitude of antigens to the immune system. This complexity has proved challenging to our efforts to understand merozoite invasion and malaria immunity, and to developing merozoite antigens as malaria vaccines. In recent years, there has been major progress in this field, and several merozoite surface proteins show strong potential as malaria vaccines. Our current knowledge on this topic is reviewed, highlighting recent advances and research priorities. The authors summarize current knowledge of merozoite surface proteins of malaria parasites; their function in invasion, processing of surface proteins before, during and after invasion, their importance as targets of immunity, and the current status of malaria vaccines that target merozoite surface proteins.
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Affiliation(s)
- James G Beeson
- Burnet Institute for Medical Research and Public Health, 85 Commercial Road, Melbourne, Victoria, Australia Department of Microbiology, Monash University, Clayton, Victoria, Australia Department of Medicine, University of Melbourne, Parkville, Victoria, Australia
| | - Damien R Drew
- Burnet Institute for Medical Research and Public Health, 85 Commercial Road, Melbourne, Victoria, Australia
| | - Michelle J Boyle
- Burnet Institute for Medical Research and Public Health, 85 Commercial Road, Melbourne, Victoria, Australia
| | - Gaoqian Feng
- Burnet Institute for Medical Research and Public Health, 85 Commercial Road, Melbourne, Victoria, Australia
| | - Freya J I Fowkes
- Burnet Institute for Medical Research and Public Health, 85 Commercial Road, Melbourne, Victoria, Australia Department of Epidemiology and Preventive Medicine, Monash University, Clayton, Victoria, Australia School of Population Health, University of Melbourne, Parkville, Victoria, Australia
| | - Jack S Richards
- Burnet Institute for Medical Research and Public Health, 85 Commercial Road, Melbourne, Victoria, Australia Department of Microbiology, Monash University, Clayton, Victoria, Australia Department of Medicine, University of Melbourne, Parkville, Victoria, Australia
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20
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Serine Proteases of Malaria Parasite Plasmodium falciparum: Potential as Antimalarial Drug Targets. Interdiscip Perspect Infect Dis 2014; 2014:453186. [PMID: 24799897 PMCID: PMC3988940 DOI: 10.1155/2014/453186] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Revised: 01/02/2014] [Accepted: 01/07/2014] [Indexed: 01/08/2023] Open
Abstract
Malaria is a major global parasitic disease and a cause of enormous mortality and morbidity. Widespread drug resistance against currently available antimalarials warrants the identification of novel drug targets and development of new drugs. Malarial proteases are a group of molecules that serve as potential drug targets because of their essentiality for parasite life cycle stages and feasibility of designing specific inhibitors against them. Proteases belonging to various mechanistic classes are found in P. falciparum, of which serine proteases are of particular interest due to their involvement in parasite-specific processes of egress and invasion. In P. falciparum, a number of serine proteases belonging to chymotrypsin, subtilisin, and rhomboid clans are found. This review focuses on the potential of P. falciparum serine proteases as antimalarial drug targets.
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21
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Walker DM, Oghumu S, Gupta G, McGwire BS, Drew ME, Satoskar AR. Mechanisms of cellular invasion by intracellular parasites. Cell Mol Life Sci 2013; 71:1245-63. [PMID: 24221133 DOI: 10.1007/s00018-013-1491-1] [Citation(s) in RCA: 107] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Revised: 10/04/2013] [Accepted: 10/07/2013] [Indexed: 12/22/2022]
Abstract
Numerous disease-causing parasites must invade host cells in order to prosper. Collectively, such pathogens are responsible for a staggering amount of human sickness and death throughout the world. Leishmaniasis, Chagas disease, toxoplasmosis, and malaria are neglected diseases and therefore are linked to socio-economical and geographical factors, affecting well-over half the world's population. Such obligate intracellular parasites have co-evolved with humans to establish a complexity of specific molecular parasite-host cell interactions, forming the basis of the parasite's cellular tropism. They make use of such interactions to invade host cells as a means to migrate through various tissues, to evade the host immune system, and to undergo intracellular replication. These cellular migration and invasion events are absolutely essential for the completion of the lifecycles of these parasites and lead to their for disease pathogenesis. This review is an overview of the molecular mechanisms of protozoan parasite invasion of host cells and discussion of therapeutic strategies, which could be developed by targeting these invasion pathways. Specifically, we focus on four species of protozoan parasites Leishmania, Trypanosoma cruzi, Plasmodium, and Toxoplasma, which are responsible for significant morbidity and mortality.
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Affiliation(s)
- Dawn M Walker
- Department of Microbial Infection and Immunity, Wexner Medical Center, The Ohio State University, Columbus, OH, 43210, USA
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22
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Sequential processing of merozoite surface proteins during and after erythrocyte invasion by Plasmodium falciparum. Infect Immun 2013; 82:924-36. [PMID: 24218484 DOI: 10.1128/iai.00866-13] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Plasmodium falciparum causes malaria disease during the asexual blood stages of infection when merozoites invade erythrocytes and replicate. Merozoite surface proteins (MSPs) are proposed to play a role in the initial binding of merozoites to erythrocytes, but precise roles remain undefined. Based on electron microscopy studies of invading Plasmodium merozoites, it is proposed that the majority of MSPs are cleaved and shed from the surface during invasion, perhaps to release receptor-ligand interactions. In this study, we demonstrate that there is not universal cleavage of MSPs during invasion. Instead, there is sequential and coordinated cleavage and shedding of proteins, indicating a diversity of roles for surface proteins during and after invasion. While MSP1 and peripheral surface proteins such as MSP3, MSP7, serine repeat antigen 4 (SERA4), and SERA5 are cleaved and shed at the tight junction between the invading merozoite and erythrocyte, the glycosylphosphatidylinositol (GPI)-anchored proteins MSP2 and MSP4 are carried into the erythrocyte without detectable processing. Following invasion, MSP2 rapidly degrades within 10 min, whereas MSP4 is maintained for hours. This suggests that while some proteins that are shed upon invasion may have roles in initial contact steps, others function during invasion and are then rapidly degraded, whereas others are internalized for roles during intraerythrocytic development. Interestingly, anti-MSP2 antibodies did not inhibit invasion and instead were carried into erythrocytes and maintained for approximately 20 h without inhibiting parasite development. These findings provide new insights into the mechanisms of invasion and knowledge to advance the development of new drugs and vaccines against malaria.
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23
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Cruz-Gallardo I, Díaz-Moreno I, Díaz-Quintana A, Donaire A, Velázquez-Campoy A, Curd RD, Rangachari K, Birdsall B, Ramos A, Holder AA, De la Rosa MA. Antimalarial activity of cupredoxins: the interaction of Plasmodium merozoite surface protein 119 (MSP119) and rusticyanin. J Biol Chem 2013; 288:20896-20907. [PMID: 23749994 PMCID: PMC3774360 DOI: 10.1074/jbc.m113.460162] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2013] [Revised: 06/07/2013] [Indexed: 11/06/2022] Open
Abstract
The discovery of effective new antimalarial agents is urgently needed. One of the most frequently studied molecules anchored to the parasite surface is the merozoite surface protein-1 (MSP1). At red blood cell invasion MSP1 is proteolytically processed, and the 19-kDa C-terminal fragment (MSP119) remains on the surface and is taken into the red blood cell, where it is transferred to the food vacuole and persists until the end of the intracellular cycle. Because a number of specific antibodies inhibit erythrocyte invasion and parasite growth, MSP119 is therefore a promising target against malaria. Given the structural homology of cupredoxins with the Fab domain of monoclonal antibodies, an approach combining NMR and isothermal titration calorimetry (ITC) measurements with docking calculations based on BiGGER is employed on MSP119-cupredoxin complexes. Among the cupredoxins tested, rusticyanin forms a well defined complex with MSP119 at a site that overlaps with the surface recognized by the inhibitory antibodies. The addition of holo-rusticyanin to infected cells results in parasitemia inhibition, but negligible effects on parasite growth can be observed for apo-rusticyanin and other proteins of the cupredoxin family. These findings point to rusticyanin as an excellent therapeutic tool for malaria treatment and provide valuable information for drug design.
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Affiliation(s)
- Isabel Cruz-Gallardo
- From the Instituto de Bioquímica Vegetal y Fotosíntesis (IBVF), cicCartuja, Universidad de Sevilla-CSIC, Avenida Américo Vespucio 49, Sevilla 41092, Spain
| | - Irene Díaz-Moreno
- From the Instituto de Bioquímica Vegetal y Fotosíntesis (IBVF), cicCartuja, Universidad de Sevilla-CSIC, Avenida Américo Vespucio 49, Sevilla 41092, Spain
| | - Antonio Díaz-Quintana
- From the Instituto de Bioquímica Vegetal y Fotosíntesis (IBVF), cicCartuja, Universidad de Sevilla-CSIC, Avenida Américo Vespucio 49, Sevilla 41092, Spain
| | - Antonio Donaire
- the Departamento de Química Inorgánica, Facultad de Química, Universidad de Murcia, Campus Universitario de Espinardo, Murcia 30100, Spain
| | - Adrián Velázquez-Campoy
- the Instituto de Biocomputación y Física de Sistemas complejos (BIFI), Universidad de Zaragoza, c/Mariano Esquillor, Zaragoza 50018, Spain
| | | | | | - Berry Birdsall
- Molecular Structure Division, Medical Research Council (MRC) National Institute for Medical Research, The Ridgeway, Mill Hill, London W7 1AA, United Kingdom
| | - Andres Ramos
- Molecular Structure Division, Medical Research Council (MRC) National Institute for Medical Research, The Ridgeway, Mill Hill, London W7 1AA, United Kingdom
| | | | - Miguel A De la Rosa
- From the Instituto de Bioquímica Vegetal y Fotosíntesis (IBVF), cicCartuja, Universidad de Sevilla-CSIC, Avenida Américo Vespucio 49, Sevilla 41092, Spain,.
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Marques AF, Esser D, Rosenthal PJ, Kassack MU, Lima LMTR. Falcipain-2 inhibition by suramin and suramin analogues. Bioorg Med Chem 2013; 21:3667-73. [PMID: 23680445 DOI: 10.1016/j.bmc.2013.04.047] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2013] [Revised: 04/09/2013] [Accepted: 04/17/2013] [Indexed: 10/26/2022]
Abstract
Falcipain-2 is a cysteine protease of the malaria parasite Plasmodium falciparum that plays a key role in the hydrolysis of hemoglobin, a process that is required by intraerythrocytic parasites to obtain amino acids. In this work we show that the polysulfonated napthylurea suramin is capable of binding to falcipain-2, inhibiting its catalytic activity at nanomolar concentrations against both synthetic substrates and the natural substrate hemoglobin. Kinetic measurements suggest that the inhibition occurs through an noncompetitive allosteric mechanism, eliciting substrate inhibition. Smaller suramin analogues and those with substituted methyl groups also showed inhibition within the nanomolar range. Our results identify the suramin family as a potential starting point for the design of falcipain-2 inhibitor antimalarials that act through a novel inhibition mechanism.
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Affiliation(s)
- Adriana Fonseca Marques
- Laboratory for Pharmaceutical Biotechnology, School of Pharmacy, Federal University of Rio de Janeiro, CCS, Bss34, Ilha do Fundão, 21941-590 Rio de Janeiro, RJ, Brazil
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25
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Lamas Longarela O, Schmidt TT, Schöneweis K, Romeo R, Wedemeyer H, Urban S, Schulze A. Proteoglycans act as cellular hepatitis delta virus attachment receptors. PLoS One 2013; 8:e58340. [PMID: 23505490 PMCID: PMC3591349 DOI: 10.1371/journal.pone.0058340] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2012] [Accepted: 02/03/2013] [Indexed: 12/12/2022] Open
Abstract
The hepatitis delta virus (HDV) is a small, defective RNA virus that requires the presence of the hepatitis B virus (HBV) for its life cycle. Worldwide more than 15 million people are co-infected with HBV and HDV. Although much effort has been made, the early steps of the HBV/HDV entry process, including hepatocyte attachment and receptor interaction are still not fully understood. Numerous possible cellular HBV/HDV binding partners have been described over the last years; however, so far only heparan sulfate proteoglycans have been functionally confirmed as cell-associated HBV attachment factors. Recently, it has been suggested that ionotrophic purinergic receptors (P2XR) participate as receptors in HBV/HDV entry. Using the HBV/HDV susceptible HepaRG cell line and primary human hepatocytes (PHH), we here demonstrate that HDV entry into hepatocytes depends on the interaction with the glycosaminoglycan (GAG) side chains of cellular heparan sulfate proteoglycans. We furthermore provide evidence that P2XR are not involved in HBV/HDV entry and that effects observed with inhibitors for these receptors are a consequence of their negative charge. HDV infection was abrogated by soluble GAGs and other highly sulfated compounds. Enzymatic removal of defined carbohydrate structures from the cell surface using heparinase III or the obstruction of GAG synthesis by sodium chlorate inhibited HDV infection of HepaRG cells. Highly sulfated P2XR antagonists blocked HBV/HDV infection of HepaRG cells and PHH. In contrast, no effect on HBV/HDV infection was found when uncharged P2XR antagonists or agonists were applied. In summary, HDV infection, comparable to HBV infection, requires binding to the carbohydrate side chains of hepatocyte-associated heparan sulfate proteoglycans as attachment receptors, while P2XR are not actively involved.
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Affiliation(s)
- Oscar Lamas Longarela
- Department of Infectious Diseases, Molecular Virology, University Hospital Heidelberg, Heidelberg, Baden-Württemberg, Germany
| | - Tobias T. Schmidt
- Department of Infectious Diseases, Molecular Virology, University Hospital Heidelberg, Heidelberg, Baden-Württemberg, Germany
| | - Katrin Schöneweis
- Department of Infectious Diseases, Molecular Virology, University Hospital Heidelberg, Heidelberg, Baden-Württemberg, Germany
| | - Raffaella Romeo
- First Division of Gastroenterology, Fondazione IRCCS Ca’Granda Ospedale Maggiore Policlinico, University of Milan, Milan, Italy
| | - Heiner Wedemeyer
- Department of Gastroenterology, Hepatology and Endocrinology, Hannover Medical School, Hannover, Germany
| | - Stephan Urban
- Department of Infectious Diseases, Molecular Virology, University Hospital Heidelberg, Heidelberg, Baden-Württemberg, Germany
| | - Andreas Schulze
- Department of Infectious Diseases, Molecular Virology, University Hospital Heidelberg, Heidelberg, Baden-Württemberg, Germany
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26
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Cruz LN, Wu Y, Craig AG, Garcia CRS. Signal transduction in Plasmodium-Red Blood Cells interactions and in cytoadherence. AN ACAD BRAS CIENC 2012; 84:555-72. [PMID: 22634746 DOI: 10.1590/s0001-37652012005000036] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2011] [Accepted: 03/09/2012] [Indexed: 12/19/2022] Open
Abstract
Malaria is responsible for more than 1.5 million deaths each year, especially among children (Snow et al. 2005). Despite of the severity of malaria situation and great effort to the development of new drug targets (Yuan et al. 2011) there is still a relative low investment toward antimalarial drugs. Briefly there are targets classes of antimalarial drugs currently being tested including: kinases, proteases, ion channel of GPCR, nuclear receptor, among others (Gamo et al. 2010). Here we review malaria signal transduction pathways in Red Blood Cells (RBC) as well as infected RBCs and endothelial cells interactions, namely cytoadherence. The last process is thought to play an important role in the pathogenesis of severe malaria. The molecules displayed on the surface of both infected erythrocytes (IE) and vascular endothelial cells (EC) exert themselves as important mediators in cytoadherence, in that they not only induce structural and metabolic changes on both sides, but also trigger multiple signal transduction processes, leading to alteration of gene expression, with the balance between positive and negative regulation determining endothelial pathology during a malaria infection.
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Affiliation(s)
- Laura N Cruz
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, Brasil
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27
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Allosteric activation of human α-thrombin through exosite 2 by suramin analogs. Arch Biochem Biophys 2012; 520:36-41. [DOI: 10.1016/j.abb.2012.02.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2011] [Revised: 02/01/2012] [Accepted: 02/01/2012] [Indexed: 11/22/2022]
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Cruz LN, Juliano MA, Budu A, Juliano L, Holder AA, Blackman MJ, Garcia CR. Extracellular ATP triggers proteolysis and cytosolic Ca²⁺ rise in Plasmodium berghei and Plasmodium yoelii malaria parasites. Malar J 2012; 11:69. [PMID: 22420332 PMCID: PMC3358241 DOI: 10.1186/1475-2875-11-69] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2011] [Accepted: 03/15/2012] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Plasmodium has a complex cell biology and it is essential to dissect the cell-signalling pathways underlying its survival within the host. METHODS Using the fluorescence resonance energy transfer (FRET) peptide substrate Abz-AIKFFARQ-EDDnp and Fluo4/AM, the effects of extracellular ATP on triggering proteolysis and Ca²⁺ signalling in Plasmodium berghei and Plasmodium yoelii malaria parasites were investigated. RESULTS The protease activity was blocked in the presence of the purinergic receptor blockers suramin (50 μM) and PPADS (50 μM) or the extracellular and intracellular calcium chelators EGTA (5 mM) and BAPTA/AM (25, 100, 200 and 500 μM), respectively for P. yoelii and P. berghei. Addition of ATP (50, 70, 200 and 250 μM) to isolated parasites previously loaded with Fluo4/AM in a Ca²⁺-containing medium led to an increase in cytosolic calcium. This rise was blocked by pre-incubating the parasites with either purinergic antagonists PPADS (50 μM), TNP-ATP (50 μM) or the purinergic blockers KN-62 (10 μM) and Ip5I (10 μM). Incubating P. berghei infected cells with KN-62 (200 μM) resulted in a changed profile of merozoite surface protein 1 (MSP1) processing as revealed by western blot assays. Moreover incubating P. berghei for 17 h with KN-62 (10 μM) led to an increase in rings forms (82% ± 4, n = 11) and a decrease in trophozoite forms (18% ± 4, n = 11). CONCLUSIONS The data clearly show that purinergic signalling modulates P. berghei protease(s) activity and that MSP1 is one target in this pathway.
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Affiliation(s)
- Laura Nogueira Cruz
- Department of Physiology, Instituto de Biociências, Universidade de São Paulo, Rua do Matão, Butantan, 05508-900 São Paulo, SP Brazil
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29
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Abstract
Malaria continues to have a significant impact on the health of the developing world. Efforts to combat this disease now focus on combination therapy in order to stem the emergence of resistant parasites. Continued efforts are needed to discover and develop new agents for use in combination antimalarial regimens. MK-4815 is a small molecule with antimalarial activity that was identified from a large pharmaceutical compound collection using a semiautomated version of a well-established in vitro assay for the erythrocytic stages of Plasmodium falciparum. In vitro studies indicate that the compound selectively accumulates in infected red blood cells and is most effective against the metabolically active late trophozoite/early schizont stages. A variety of drug-resistant field isolates of P. falciparum were found to be as sensitive to MK-4815 as the wild-type lines. MK-4815 is orally active in a P. berghei mouse model of acute malaria. In this model, where untreated animals succumb to infection 10 to 12 days postinfection, MK-4815 was completely curative when given as a single dose of 50 mg/kg, 2 doses of 25 mg/kg, or 4.5 doses of 12.5 mg/kg. In pharmacokinetic studies with mice and rhesus monkeys, MK-4815 demonstrated oral bioavailability and low clearance. In addition, MK-4815 is inexpensive to synthesize, an important characteristic for providing affordable antimalaria therapy to the developing world. The attractive biological and pharmaceutical profile of MK-4815 demonstrates its potential for use in combination with other agents in the fight against malaria.
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30
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Olivieri A, Collins CR, Hackett F, Withers-Martinez C, Marshall J, Flynn HR, Skehel JM, Blackman MJ. Juxtamembrane shedding of Plasmodium falciparum AMA1 is sequence independent and essential, and helps evade invasion-inhibitory antibodies. PLoS Pathog 2011; 7:e1002448. [PMID: 22194692 PMCID: PMC3240622 DOI: 10.1371/journal.ppat.1002448] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2010] [Accepted: 11/04/2011] [Indexed: 12/16/2022] Open
Abstract
The malarial life cycle involves repeated rounds of intraerythrocytic replication interspersed by host cell rupture which releases merozoites that rapidly invade fresh erythrocytes. Apical membrane antigen-1 (AMA1) is a merozoite protein that plays a critical role in invasion. Antibodies against AMA1 prevent invasion and can protect against malaria in vivo, so AMA1 is of interest as a malaria vaccine candidate. AMA1 is efficiently shed from the invading parasite surface, predominantly through juxtamembrane cleavage by a membrane-bound protease called SUB2, but also by limited intramembrane cleavage. We have investigated the structural requirements for shedding of Plasmodium falciparum AMA1 (PfAMA1), and the consequences of its inhibition. Mutagenesis of the intramembrane cleavage site by targeted homologous recombination abolished intramembrane cleavage with no effect on parasite viability in vitro. Examination of PfSUB2-mediated shedding of episomally-expressed PfAMA1 revealed that the position of cleavage is determined primarily by its distance from the parasite membrane. Certain mutations at the PfSUB2 cleavage site block shedding, and parasites expressing these non-cleavable forms of PfAMA1 on a background of expression of the wild type gene invade and replicate normally in vitro. The non-cleavable PfAMA1 is also functional in invasion. However – in contrast to the intramembrane cleavage site - mutations that block PfSUB2-mediated shedding could not be stably introduced into the genomic pfama1 locus, indicating that some shedding of PfAMA1 by PfSUB2 is essential. Remarkably, parasites expressing shedding-resistant forms of PfAMA1 exhibit enhanced sensitivity to antibody-mediated inhibition of invasion. Drugs that inhibit PfSUB2 activity should block parasite replication and may also enhance the efficacy of vaccines based on AMA1 and other merozoite surface proteins. The malaria parasite invades red blood cells. During invasion several parasite proteins, including a vaccine candidate called PfAMA1, are clipped from the parasite surface. Most of this clipping is performed by an enzyme called PfSUB2, but some also occurs through intramembrane cleavage. The function of this shedding is unknown. We have examined the requirements for shedding of PfAMA1, and the effects of mutations that block shedding. Mutations that block intramembrane cleavage have no effect on the parasite. We then show that PfSUB2 does not recognise a specific amino acid sequence in PfAMA1, but rather cleaves it at a position determined primarily by its distance from the parasite membrane. Certain mutations at the PfSUB2 cleavage site prevent shedding, and parasites expressing non-cleavable PfAMA1 along with unmodified PfAMA1 grow normally. However, these mutations cannot be introduced into the parasite's genome, showing that some shedding by PfSUB2 is essential for parasite survival. Parasites expressing shedding-resistant mutants of PfAMA1 show enhanced sensitivity to invasion-inhibitory antibodies, suggesting that shedding of surface proteins during invasion helps the parasite to evade potentially protective antibodies. Drugs that inhibit PfSUB2 may prevent disease and enhance the efficacy of vaccines based on PfAMA1.
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Affiliation(s)
- Anna Olivieri
- Division of Parasitology, MRC National Institute for Medical Research, Mill Hill, London, United Kingdom
| | - Christine R. Collins
- Division of Parasitology, MRC National Institute for Medical Research, Mill Hill, London, United Kingdom
| | - Fiona Hackett
- Division of Parasitology, MRC National Institute for Medical Research, Mill Hill, London, United Kingdom
| | | | - Joshua Marshall
- Division of Parasitology, MRC National Institute for Medical Research, Mill Hill, London, United Kingdom
| | - Helen R. Flynn
- Protein Analysis and Proteomics Laboratory, Clare Hall Laboratories, Cancer Research UK London Research Institute, South Mimms, Hertfordshire, United Kingdom
| | - J. Mark Skehel
- Protein Analysis and Proteomics Laboratory, Clare Hall Laboratories, Cancer Research UK London Research Institute, South Mimms, Hertfordshire, United Kingdom
| | - Michael J. Blackman
- Protein Analysis and Proteomics Laboratory, Clare Hall Laboratories, Cancer Research UK London Research Institute, South Mimms, Hertfordshire, United Kingdom
- * E-mail:
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31
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Taylor JM, Han Z. Purinergic receptor functionality is necessary for infection of human hepatocytes by hepatitis delta virus and hepatitis B virus. PLoS One 2010; 5:e15784. [PMID: 21187936 PMCID: PMC3004961 DOI: 10.1371/journal.pone.0015784] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2010] [Accepted: 11/22/2010] [Indexed: 12/18/2022] Open
Abstract
Hepatitis B virus (HBV) and hepatitis delta virus (HDV) are major sources of acute and chronic hepatitis. HDV requires the envelope proteins of HBV for the processes of assembly and infection of new cells. Both viruses are able to infect hepatocytes though previous studies have failed to determine the mechanism of entry into such cells. This study began with evidence that suramin, a symmetrical hexasulfated napthylurea, could block HDV entry into primary human hepatocytes (PHH) and was then extrapolated to incorporate findings of others that suramin is one of many compounds that can block activation of purinergic receptors. Thus other inhibitors, pyridoxal-phosphate-6-azophenyl-2′,4′-disulfonate (PPADS) and brilliant blue G (BBG), both structurally unrelated to suramin, were tested and found to inhibit HDV and HBV infections of PHH. BBG, unlike suramin and PPADS, is known to be more specific for just one purinergic receptor, P2X7. These studies provide the first evidence that purinergic receptor functionality is necessary for virus entry. Furthermore, since P2X7 activation is known to be a major component of inflammatory responses, it is proposed that HDV and HBV attachment to susceptible cells, might also contribute to inflammation in the liver, that is, hepatitis.
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Affiliation(s)
- John M Taylor
- Fox Chase Cancer Center, Philadelphia, Pennsylvania, United States of America.
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32
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Child MA, Epp C, Bujard H, Blackman MJ. Regulated maturation of malaria merozoite surface protein-1 is essential for parasite growth. Mol Microbiol 2010; 78:187-202. [PMID: 20735778 PMCID: PMC2995310 DOI: 10.1111/j.1365-2958.2010.07324.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The malaria parasite Plasmodium falciparum invades erythrocytes where it replicates to produce invasive merozoites, which eventually egress to repeat the cycle. Merozoite surface protein-1 (MSP1), a prime malaria vaccine candidate and one of the most abundant components of the merozoite surface, is implicated in the ligand-receptor interactions leading to invasion. MSP1 is extensively proteolytically modified, first just before egress and then during invasion. These primary and secondary processing events are mediated respectively, by two parasite subtilisin-like proteases, PfSUB1 and PfSUB2, but the function and biological importance of the processing is unknown. Here, we examine the regulation and significance of MSP1 processing. We show that primary processing is ordered, with the primary processing site closest to the C-terminal end of MSP1 being cleaved last, irrespective of polymorphisms throughout the rest of the molecule. Replacement of the secondary processing site, normally refractory to PfSUB1, with a PfSUB1-sensitive site, is deleterious to parasite growth. Our findings show that correct spatiotemporal regulation of MSP1 maturation is crucial for the function of the protein and for maintenance of the parasite asexual blood-stage life cycle.
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Affiliation(s)
- Matthew A Child
- Division of Parasitology, MRC National Institute for Medical Research, Mill Hill, London NW7 1AA, UK
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33
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Proteoglycans in host-pathogen interactions: molecular mechanisms and therapeutic implications. Expert Rev Mol Med 2010; 12:e5. [PMID: 20113533 DOI: 10.1017/s1462399409001367] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Many microbial pathogens subvert proteoglycans for their adhesion to host tissues, invasion of host cells, infection of neighbouring cells, dissemination into the systemic circulation, and evasion of host defence mechanisms. Where studied, specific virulence factors mediate these proteoglycan-pathogen interactions, which are thus thought to affect the onset, progression and outcome of infection. Proteoglycans are composites of glycosaminoglycan (GAG) chains attached covalently to specific core proteins. Proteoglycans are expressed ubiquitously on the cell surface, in intracellular compartments, and in the extracellular matrix. GAGs mediate the majority of ligand-binding activities of proteoglycans, and many microbial pathogens elaborate cell-surface and secreted factors that interact with GAGs. Some pathogens also modulate the expression and function of proteoglycans through known virulence factors. Several GAG-binding pathogens can no longer attach to and invade host cells whose GAG expression has been reduced by mutagenesis or enzymatic treatment. Furthermore, GAG antagonists have been shown to inhibit microbial attachment and host cell entry in vitro and reduce virulence in vivo. Together, these observations underscore the biological significance of proteoglycan-pathogen interactions in infectious diseases.
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Lima LMTR, Becker CF, Giesel GM, Marques AF, Cargnelutti MT, de Oliveira Neto M, Monteiro RQ, Verli H, Polikarpov I. Structural and thermodynamic analysis of thrombin:suramin interaction in solution and crystal phases. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2009; 1794:873-81. [PMID: 19332154 DOI: 10.1016/j.bbapap.2009.03.011] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2008] [Revised: 02/24/2009] [Accepted: 03/09/2009] [Indexed: 11/15/2022]
Abstract
Suramin is a hexasulfonated naphthylurea which has been recently characterized as a non-competitive inhibitor of human alpha-thrombin activity over fibrinogen, although its binding site and mode of interaction with the enzyme remain elusive. Here, we determined two X-ray structure of the thrombin:suramin complex, refined at 2.4 A resolution. While a single thrombin:suramin complex was found in the asymmetric unit cell of the crystal, some of the crystallographic contacts with symmetrically related molecules are mediated by both the enzyme and the ligand. Molecular dynamics simulations with the 1:1 complex demonstrate a large rearrangement of suramin in the complex, but with the protein scaffold and the more extensive protein-ligand regions keep unchanged. Small-angle X-ray scattering measurements at high micromolar concentration demonstrate a suramin-induced dimerization of the enzyme. These data indicating a dissimilar binding mode in the monomeric and oligomeric states, with a monomeric, 1:1 complex to be more likely to exist at the thrombin physiological, nanomolar concentration range. Collectively, close understanding on the structural basis for interaction is given which might establish a basis for design of suramin analogues targeting thrombin.
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Affiliation(s)
- Luis Maurício T R Lima
- Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, 21941-590, Rio de Janeiro, RJ, Brazil.
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35
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Polyanionic drugs and viral oncogenesis: a novel approach to control infection, tumor-associated inflammation and angiogenesis. Molecules 2008; 13:2758-85. [PMID: 19002078 PMCID: PMC6245429 DOI: 10.3390/molecules13112758] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2008] [Revised: 10/13/2008] [Accepted: 10/29/2008] [Indexed: 01/01/2023] Open
Abstract
Polyanionic macromolecules are extremely abundant both in the extracellular environment and inside the cell, where they are readily accessible to many proteins for interactions that play a variety of biological roles. Among polyanions, heparin, heparan sulfate proteoglycans (HSPGs) and glycosphingolipids (GSLs) are widely distributed in biological fluids, at the cell membrane and inside the cell, where they are implicated in several physiological and/or pathological processes such as infectious diseases, angiogenesis and tumor growth. At a molecular level, these processes are mainly mediated by microbial proteins, cytokines and receptors that exert their functions by binding to HSPGs and/or GSLs, suggesting the possibility to use polyanionic antagonists as efficient drugs for the treatment of infectious diseases and cancer. Polysulfated (PS) or polysulfonated (PSN) compounds are a heterogeneous group of natural, semi-synthetic or synthetic molecules whose prototypes are heparin and suramin. Different structural features confer to PS/PSN compounds the capacity to bind and inhibit the biological activities of those same heparin-binding proteins implicated in infectious diseases and cancer. In this review we will discuss the state of the art and the possible future development of polyanionic drugs in the treatment of infectious diseases and cancer.
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36
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Wigdal SS, Anderson JL, Vidugiris GJ, Shultz J, Wood KV, Fan F. A novel bioluminescent protease assay using engineered firefly luciferase. CURRENT CHEMICAL GENOMICS 2008; 2:16-28. [PMID: 20161840 PMCID: PMC2803436 DOI: 10.2174/1875397300802010016] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/20/2008] [Revised: 08/20/2008] [Accepted: 08/23/2008] [Indexed: 11/22/2022]
Abstract
Proteases play important roles in a variety of disease processes. Understanding their biological functions underpins the efforts of drug discovery. We have developed a bioluminescent protease assay using a circularly permuted form of firefly luciferase, wherein the native enzyme termini were joined by a peptide containing a protease site of interest. Protease cleavage of these mutant luciferases greatly activates the enzyme, typically over 100 fold. The mutant luciferase substrates are easily generated by molecular cloning and cell-free translation reactions and thus the protease substrates do not need to be chemically synthesized or purchased. The assay has broad applicability using a variety of proteases and their cognate sites and can sensitively detect protease activity. In this report we further demonstrate its utility for the evaluation of protease recognition sequence specificity and subsequent establishment of an optimized assay for the identification and characterization of protease inhibitors using high throughput screening.
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Affiliation(s)
- Susan S Wigdal
- Promega Corporation, 2800 Woods Hollow Road, Madison, WI 53711, USA
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37
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Dowse TJ, Koussis K, Blackman MJ, Soldati-Favre D. Roles of proteases during invasion and egress by Plasmodium and Toxoplasma. Subcell Biochem 2008; 47:121-139. [PMID: 18512347 DOI: 10.1007/978-0-387-78267-6_10] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Apicomplexan pathogens replicate exclusively within the confines of a host cell. Entry into (invasion) and exit from (egress) these cells requires an array of specialized parasite molecules, many of which have long been considered to have potential as targets of drug or vaccine-based therapies. In this chapter the authors discuss the current state of knowledge regarding the role of parasite proteolytic enzymes in these critical steps in the life cycle of two clinically important apicomplexan genera, Plasmodium and Toxoplasma. At least three distinct proteases of the cysteine mechanistic class have been implicated in egress of the malaria parasite from cells of its vertebrate and insect host. In contrast, the bulk of the evidence indicates a prime role for serine proteases of the subtilisin and rhomboid families in invasion by both parasites. Whereas proteases involved in egress may function predominantly to degrade host cell structures, proteases involved in invasion probably act primarily as maturases and 'sheddases', required to activate and ultimately remove ligands involved in interactions with the host cell.
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Affiliation(s)
- Timothy J Dowse
- Department of Biological Sciences, Imperial College, London, UK
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38
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Montero E, Rafiq S, Heck S, Lobo CA. Inhibition of human erythrocyte invasion by Babesia divergens using serine protease inhibitors. Mol Biochem Parasitol 2007; 153:80-4. [PMID: 17320984 DOI: 10.1016/j.molbiopara.2007.01.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2006] [Revised: 01/12/2007] [Accepted: 01/17/2007] [Indexed: 11/21/2022]
Affiliation(s)
- Estrella Montero
- Department of Blood-Borne Parasites, Lindsley Kimball Research Institute, New York Blood Center, 310 E. 67 Street, New York, NY 10021, United States
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Babon JJ, Morgan WD, Kelly G, Eccleston JF, Feeney J, Holder AA. Structural studies on Plasmodium vivax merozoite surface protein-1. Mol Biochem Parasitol 2007; 153:31-40. [PMID: 17343930 DOI: 10.1016/j.molbiopara.2007.01.015] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2006] [Revised: 01/17/2007] [Accepted: 01/17/2007] [Indexed: 11/28/2022]
Abstract
Plasmodium vivax infection is the second most common cause of malaria throughout the world. Like other Plasmodium species, P. vivax has a large protein complex, MSP-1, located on the merozoite surface. The C-terminal MSP-1 sub-unit, MSP-1(42), is cleaved during red blood cell invasion, causing the majority of the complex to be shed and leaving only a small 15kDa sub-unit, MSP-1(19), on the merozite surface. MSP-1(19) is considered a strong vaccine candidate. We have determined the solution structure of MSP-1(19) from P. vivax using nuclear magnetic resonance (NMR) and show that, like in other Plasmodium species, it consists of two EGF-like domains that are oriented head-to-tail. The protein has a flat, disk-like shape with a highly charged surface. When MSP-1(19) is part of the larger MSP-1(42) precursor it exists as an independent domain with no stable contacts to the rest of the sub-unit. Gel filtration and analytical ultracentrifugation experiments indicate that P. vivax MSP-1(42) exists as a dimer in solution. MSP-1(19) itself is a monomer, however, 35 amino-acids immediately upstream of its N-terminus are sufficient to cause dimerization. Our data suggest that if MSP-1(42) exists as a dimer in vivo, secondary processing would cause the dissociation of two tightly linked MSP-1(19) proteins on the merozoite surface just prior to invasion.
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Affiliation(s)
- Jeffrey J Babon
- Division of Parasitology, National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, United Kingdom.
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40
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Pachebat JA, Kadekoppala M, Grainger M, Dluzewski AR, Gunaratne RS, Scott-Finnigan TJ, Ogun SA, Ling IT, Bannister LH, Taylor HM, Mitchell GH, Holder AA. Extensive proteolytic processing of the malaria parasite merozoite surface protein 7 during biosynthesis and parasite release from erythrocytes. Mol Biochem Parasitol 2006; 151:59-69. [PMID: 17097159 DOI: 10.1016/j.molbiopara.2006.10.006] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2006] [Revised: 09/15/2006] [Accepted: 10/11/2006] [Indexed: 11/21/2022]
Abstract
In Plasmodium falciparum, merozoite surface protein 7 (MSP7) was originally identified as a 22kDa protein on the merozoite surface and associated with the MSP1 complex shed during erythrocyte invasion. MSP7 is synthesised in schizonts as a 351-amino acid precursor that undergoes proteolytic processing. During biosynthesis the MSP1 and MSP7 precursors form a complex that is targeted to the surface of developing merozoites. In the sequential proteolytic processing of MSP7, N- and C-terminal 20 and 33kDa products of primary processing, MSP7(20) and MSP7(33) are formed and MSP7(33) remains bound to full length MSP1. Later in the mature schizont, MSP7(20) disappears from the merozoite surface and on merozoite release MSP7(33) undergoes a secondary cleavage yielding the 22kDa MSP7(22) associated with MSP1. In free merozoites, both MSP7(22) and a further cleaved product, MSP7(19) present only in some parasite lines, were detected; these two derivatives are shed as part of the protein complex with MSP1 fragments during erythrocyte invasion. Primary processing of MSP7 is brefeldin A-sensitive while secondary processing is resistant to both calcium chelators and serine protease inhibitors. Primary processing of MSP7 occurs prior to that of MSP1 in a post-Golgi compartment, whereas the secondary cleavage occurs on the surface of the developing merozoite, possibly at the time of MSP1 primary processing and well before the secondary processing of MSP1.
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Affiliation(s)
- Justin A Pachebat
- Division of Parasitology, MRC National Institute for Medical Research, Mill Hill, London NW1 1AA, UK
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41
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Green JL, Hinds L, Grainger M, Knuepfer E, Holder AA. Plasmodium thrombospondin related apical merozoite protein (PTRAMP) is shed from the surface of merozoites by PfSUB2 upon invasion of erythrocytes. Mol Biochem Parasitol 2006; 150:114-7. [PMID: 16879884 DOI: 10.1016/j.molbiopara.2006.06.010] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2006] [Revised: 06/26/2006] [Accepted: 06/26/2006] [Indexed: 10/24/2022]
Affiliation(s)
- Judith L Green
- Division of Parasitology, MRC National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, UK.
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42
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Harris PK, Yeoh S, Dluzewski AR, O'Donnell RA, Withers-Martinez C, Hackett F, Bannister LH, Mitchell GH, Blackman MJ. Molecular identification of a malaria merozoite surface sheddase. PLoS Pathog 2005; 1:241-51. [PMID: 16322767 PMCID: PMC1291349 DOI: 10.1371/journal.ppat.0010029] [Citation(s) in RCA: 152] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2005] [Accepted: 10/12/2005] [Indexed: 11/19/2022] Open
Abstract
Proteolytic shedding of surface proteins during invasion by apicomplexan parasites is a widespread phenomenon, thought to represent a mechanism by which the parasites disengage adhesin-receptor complexes in order to gain entry into their host cell. Erythrocyte invasion by merozoites of the malaria parasite Plasmodium falciparum requires the shedding of ectodomain components of two essential surface proteins, called MSP1 and AMA1. Both are released by the same merozoite surface "sheddase," but the molecular identity and mode of action of this protease is unknown. Here we identify it as PfSUB2, an integral membrane subtilisin-like protease (subtilase). We show that PfSUB2 is stored in apical secretory organelles called micronemes. Upon merozoite release it is secreted onto the parasite surface and translocates to its posterior pole in an actin-dependent manner, a trafficking pattern predicted of the sheddase. Subtilase propeptides are usually selective inhibitors of their cognate protease, and the PfSUB2 propeptide is no exception; we show that recombinant PfSUB2 propeptide binds specifically to mature parasite-derived PfSUB2 and is a potent, selective inhibitor of MSP1 and AMA1 shedding, directly establishing PfSUB2 as the sheddase. PfSUB2 is a new potential target for drugs designed to prevent erythrocyte invasion by the malaria parasite.
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Affiliation(s)
- Philippa K Harris
- Division of Parasitology, National Institute for Medical Research, London, United Kingdom
| | - Sharon Yeoh
- Division of Parasitology, National Institute for Medical Research, London, United Kingdom
| | - Anton R Dluzewski
- Department of Immunobiology, Guy's, King's and St. Thomas' Hospitals School of Medicine, London, United Kingdom
- Wolfson Centre, Guy's, King's and St. Thomas' Hospitals School of Biomedical and Life Sciences, London, United Kingdom
| | - Rebecca A O'Donnell
- Division of Parasitology, National Institute for Medical Research, London, United Kingdom
| | | | - Fiona Hackett
- Division of Parasitology, National Institute for Medical Research, London, United Kingdom
| | - Lawrence H Bannister
- Wolfson Centre, Guy's, King's and St. Thomas' Hospitals School of Biomedical and Life Sciences, London, United Kingdom
| | - Graham H Mitchell
- Department of Immunobiology, Guy's, King's and St. Thomas' Hospitals School of Medicine, London, United Kingdom
| | - Michael J Blackman
- Division of Parasitology, National Institute for Medical Research, London, United Kingdom
- * To whom correspondence should be addressed. E-mail:
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43
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Vivas L, Easton A, Kendrick H, Cameron A, Lavandera JL, Barros D, de las Heras FG, Brady RL, Croft SL. Plasmodium falciparum: stage specific effects of a selective inhibitor of lactate dehydrogenase. Exp Parasitol 2005; 111:105-14. [PMID: 16098967 DOI: 10.1016/j.exppara.2005.06.007] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2005] [Revised: 06/09/2005] [Accepted: 06/29/2005] [Indexed: 11/26/2022]
Abstract
Plasmodium falciparum lactate dehydrogenase (PfLDH) is essential for ATP generation. Based on structural differences within the active site between P. falciparum and human LDH, we have identified a series of heterocyclic azole-based inhibitors that selectively bind within the PfLDH but not the human LDH (hLDH) active site and showed anti-malarial activity in vitro and in vivo. Here we expand on an azole, OXD1, from this series and found that the anti-P. falciparum activity was retained against a panel of strains independently of their anti-malarial drug sensitivity profile. Trophozoites had relatively higher PfLDH enzyme activity and PfLDH-RNA expression levels than rings and were the most susceptible stages to OXD1 exposure. This is probably linked to their increased energy requirements and consistent with glycolysis being an essential metabolic pathway for parasite survival within the erythrocyte. Further structural elaboration of these azoles could lead to the identification of compounds that target P. falciparum through such a novel mechanism and with more potent anti-malarial activity.
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Affiliation(s)
- Livia Vivas
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK.
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44
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O'Donnell RA, Blackman MJ. The role of malaria merozoite proteases in red blood cell invasion. Curr Opin Microbiol 2005; 8:422-7. [PMID: 16019257 DOI: 10.1016/j.mib.2005.06.018] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2005] [Accepted: 06/22/2005] [Indexed: 11/19/2022]
Abstract
Invasion of red blood cells by the malaria merozoite is an essential step in the life cycle of this obligate intracellular pathogen. The molecular details of invasion are only recently becoming understood, largely through studies in related apicomplexan parasites such as Toxoplasma. Protease activity is required for successful invasion to disengage interactions between parasite adhesins and host cell receptors. Shedding of at least two essential surface proteins from the merozoite is thought to occur continuously during invasion as the parasite moves into the nascent parasitophorous vacuole. This shedding is performed by way of juxtamembrane cleavage and is mediated by a sheddase, which probably belongs to the subtilisin-like superfamily. Recent revelations have shown that transmembrane adhesins that are secreted onto the Toxoplasma tachyzoite surface and capped to its posterior pole are shed by way of cleavage within their transmembrane domains. A family of intramembrane serine proteases called rhomboids have now been identified within Apicomplexa, and one Toxoplasma rhomboid has been localized to the posterior end of the parasite. This supports their role in capping proteolysis. Proteases involved in invasion constitute potential targets for the development of new protease inhibitor-based drugs.
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Affiliation(s)
- Rebecca A O'Donnell
- Division of Parasitology, National Institute for Medical Research, Mill Hill, London, NW7 1AA, UK
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45
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Carruthers VB, Blackman MJ. A new release on life: emerging concepts in proteolysis and parasite invasion. Mol Microbiol 2005; 55:1617-30. [PMID: 15752188 DOI: 10.1111/j.1365-2958.2005.04483.x] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cell invasion by apicomplexan pathogens such as the malaria parasite and Toxoplasma is accompanied by extensive proteolysis of zoite surface proteins (ZSPs) required for attachment and penetration. Although there is still little known about the proteases involved, a conceptual framework is emerging for the roles of proteolysis in cell invasion. Primary processing of ZSPs, which includes the trimming of terminal peptides or segmentation into multiple fragments, is proposed to activate these adhesive ligands for tight binding to host receptors. Secondary processing, which occurs during penetration, results in the shedding of ZSPs by one of two mechanistically distinct ways, shaving or capping. Resident surface proteins are typically shaved from the surface whereas adhesive ligands mobilized from intracellular secretory vesicles are capped to the posterior end of the parasite before being shed during the final steps of penetration. Intriguingly, recent studies have revealed that ZSPs can be released either by being cleaved adjacent to the membrane anchor or actually within the membrane itself. Mounting evidence suggests that intramembrane cleavage is catalysed by one or more integral membrane serine proteases of the Rhomboid family and we propose that several malaria adhesive ligands may be potential substrates for these enzymes. We also discuss the evidence that the key reason for ZSP shedding during invasion is to break the connection between parasite surface ligands and host receptors. The sequential proteolytic events associated with invasion by pathogenic protozoa may represent vulnerable pathways for the future development of synergistic anti-protozoal therapies.
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Affiliation(s)
- Vern B Carruthers
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA.
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46
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Murakami MT, Arruda EZ, Melo PA, Martinez AB, Calil-Eliás S, Tomaz MA, Lomonte B, Gutiérrez JM, Arni RK. Inhibition of Myotoxic Activity of Bothrops asper Myotoxin II by the Anti-trypanosomal Drug Suramin. J Mol Biol 2005; 350:416-26. [PMID: 15961104 DOI: 10.1016/j.jmb.2005.04.072] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2005] [Revised: 04/23/2005] [Accepted: 04/27/2005] [Indexed: 11/30/2022]
Abstract
Suramin, a synthetic polysulfonated compound, developed initially for the treatment of African trypanosomiasis and onchocerciasis, is currently used for the treatment of several medically relevant disorders. Suramin, heparin, and other polyanions inhibit the myotoxic activity of Lys49 phospholipase A2 analogues both in vitro and in vivo, and are thus of potential importance as therapeutic agents in the treatment of viperid snake bites. Due to its conformational flexibility around the single bonds that link the central phenyl rings to the secondary amide backbone, the symmetrical suramin molecule binds by an induced-fit mechanism complementing the hydrophobic surfaces of the dimer and adopts a novel conformation that lacks C2 symmetry in the dimeric crystal structure of the suramin-Bothrops asper myotoxin II complex. The simultaneous binding of suramin at the surfaces of the two monomers partially restricts access to the nominal active sites and significantly changes the overall charge of the interfacial recognition face of the protein, resulting in the inhibition of myotoxicity.
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Affiliation(s)
- Mário T Murakami
- Departament of Physics, IBILCE/UNESP, São José do Rio Preto, SP, Brazil
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47
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Morgan WD, Lock MJ, Frenkiel TA, Grainger M, Holder AA. Malaria parasite-inhibitory antibody epitopes on Plasmodium falciparum merozoite surface protein-1(19) mapped by TROSY NMR. Mol Biochem Parasitol 2005; 138:29-36. [PMID: 15500913 DOI: 10.1016/j.molbiopara.2004.06.014] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2004] [Revised: 06/23/2004] [Accepted: 06/30/2004] [Indexed: 10/26/2022]
Abstract
Plasmodium falciparum merozoite surface protein 1 (MSP1)(19), the C-terminal fragment of merozoite surface protein 1, is a leading candidate antigen for development of a vaccine against the blood stages of the malaria parasite. Many human and animal studies have indicated the importance of MSP1(19)-specific immune responses. Anti-MSP1(19) antibodies can prevent invasion of red blood cells by P. falciparum parasites in vitro. However, the fine specificity of anti-MSP1(19) antibodies is also important, as only a fraction of monoclonal antibodies (mAbs) have parasite-inhibitory activity in vitro. Human sera from malaria-endemic locations show strong MSP1(19) reactivity, but individual serum samples vary greatly in inhibitory activity. NMR is an excellent method for studying protein-protein interactions, and has been used widely to study binding of peptides representing known epitopes (as well as non-protein antigens) to antibodies and antibody fragments. The recent development of transverse relaxation optimized spectroscopy (TROSY) and related methods has significantly extended the maximum size limit of molecules that can be studied by NMR. TROSY NMR experiments produce high quality spectra of Fab complexes that allow the mapping of epitopes by the chemical shift perturbation technique on a complete, folded protein antigen such as MSP1(19). We studied the complexes of P. falciparum MSP1(19) with Fab fragments from three monoclonal antibodies. Two of these antibodies have parasite-inhibitory activity in vitro, while the third is non-inhibitory. NMR epitope mapping showed a close relationship between binding sites for the two inhibitory antibodies, distinct from the location of the non-inhibitory antibody. Together with a previously published crystal structure of the P. falciparum MSP1(19) complex with the Fab fragment of another non-inhibitory antibody, these results revealed a surface on MSP1(19) where inhibitory antibodies bind. This information will be useful in evaluating the anti-MSP1(19) immune response in natural populations from endemic areas, as well as in vaccine trials. It will also be valuable for optimizing the MSP1(19) antigen by rational vaccine design. This work also shows that TROSY NMR techniques are very effective for mapping conformational epitopes at the level of individual residues on small- to medium-sized proteins, provided that the antigen can be expressed in a system amenable to stable isotope labelling, such as bacteria or yeast.
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Affiliation(s)
- William D Morgan
- Division of Parasitology and MRC Biomedical NMR Centre, National Institute for Medical Research, The Ridgeway, Mill Hill, London NW71AA, UK.
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48
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Abstract
The life cycle of the malaria parasite contains three distinct invasive forms, or zoites. For at least two of these--the sporozoite and the blood-stage merozoite--invasion into their respective host cell requires the activity of parasite proteases. This review summarizes the evidence for this, discusses selected well-described proteolytic modifications linked to invasion, and describes recent progress towards identifying the proteases involved.
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Affiliation(s)
- Michael J Blackman
- Division of Parasitology, National Institute for Medical Research, Mill Hill, London NW7 1AA, UK.
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49
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Dowse T, Soldati D. Host cell invasion by the apicomplexans: the significance of microneme protein proteolysis. Curr Opin Microbiol 2004; 7:388-96. [PMID: 15358257 DOI: 10.1016/j.mib.2004.06.013] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Intracellular life-style has been adopted by many pathogens as a successful immune evasion mechanism. To gain entry to a large variety of host cells and to establish an intracellular niche, Toxoplasma gondii and other apicomplexans rely on an active process distinct from phagocytosis. Calcium-regulated secretion of microneme proteins and parasite actin polymerization together with the action of at least one myosin motor act in concert to generate the gliding motility necessary to propel the parasite into host cells. During this active penetration, host cell transmembrane proteins are excluded from the forming parasitophorous vacuole hence conferring the resistance to acidification and degradative fusion. Apicomplexans possess a large repertoire of microneme proteins that contribute to invasion, but their precise role and the level of functional redundancy remain to be evaluated. Remarkably, most microneme proteins are proteolytically cleaved during biogenesis and post-exocytosis. The significance of the processing events and the identification of the proteases implicated are the object of intensive investigations. These proteases may constitute potential drug targets for intervention against malaria and other diseases caused by these parasites.
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Affiliation(s)
- Timothy Dowse
- Department of Biological Sciences, Imperial College London, Sir Alexander Fleming Building, South Kensington Campus, London SW7 2AZ, UK
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50
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Dekker C, Uthaipibull C, Calder LJ, Lock M, Grainger M, Morgan WD, Dodson GG, Holder AA. Inhibitory and neutral antibodies to Plasmodium falciparum MSP119 form ring structures with their antigen. Mol Biochem Parasitol 2004; 137:143-9. [PMID: 15279960 DOI: 10.1016/j.molbiopara.2004.05.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2004] [Revised: 05/15/2004] [Accepted: 05/17/2004] [Indexed: 10/26/2022]
Abstract
Blood-stage malaria vaccine candidates include surface proteins of the merozoite. Antibodies to these proteins may either block essential steps during invasion or render the merozoite susceptible to phagocytosis or complement-mediated degradation. Structural information on merozoite surface proteins complexed to antibodies provides crucial information for knowledge-based vaccine design. The major merozoite surface protein MSP1 is an abundant surface molecule in Plasmodium falciparum. Only a subset of antibodies against MSP119 inhibits invasion (inhibitory antibodies), whereas other antibodies binding to MSP119 have no effect on invasion (neutral antibodies). Here we report on the complex of MSP119 with both inhibitory monoclonal antibody 12.10 and neutral monoclonal antibody 2F10. The complexes were established using both whole IgG's and Fab fragments, and analysed by dynamic light scattering, electron microscopy and analytical ultra centrifugation. Specific ring structures were formed in the ternary complex with the two antibodies, providing direct evidence of non-overlapping epitopes on MSP119. Mutational studies also indicated that the epitopes of the inhibitory and neutral antibodies are spatially remote.
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MESH Headings
- Animals
- Antibodies, Monoclonal/chemistry
- Antibodies, Monoclonal/immunology
- Antibodies, Monoclonal/metabolism
- Antibodies, Protozoan/chemistry
- Antibodies, Protozoan/immunology
- Antibodies, Protozoan/metabolism
- Antigen-Antibody Complex/chemistry
- Antigens, Protozoan/chemistry
- Antigens, Protozoan/immunology
- Antigens, Protozoan/metabolism
- DNA Mutational Analysis
- Epitope Mapping
- Epitopes/genetics
- Epitopes/immunology
- Merozoite Surface Protein 1/chemistry
- Merozoite Surface Protein 1/immunology
- Merozoite Surface Protein 1/metabolism
- Microscopy, Electron
- Models, Molecular
- Plasmodium falciparum/immunology
- Protein Binding
- Protein Conformation
- Protein Structure, Quaternary
- Ultracentrifugation
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Affiliation(s)
- Carien Dekker
- Division of Parasitology, National Institute for Medical Research, The Ridgeway, London NW7 1AA, UK.
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