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Ogwang R, Murugu L, Nkumama IN, Nyamako L, Kai O, Mwai K, Murungi L, Idro R, Bejon P, Tuju J, Kinyanjui SM, Osier FHA. Bi-isotype immunoglobulins enhance antibody-mediated neutrophil activity against Plasmodium falciparum parasites. Front Immunol 2024; 15:1360220. [PMID: 38650925 PMCID: PMC11033408 DOI: 10.3389/fimmu.2024.1360220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Accepted: 03/19/2024] [Indexed: 04/25/2024] Open
Abstract
Background Malaria remains a major global health priority, and monoclonal antibodies (mAbs) are emerging as potential new tools to support efforts to control the disease. Recent data suggest that Fc-dependent mechanisms of immunity are important mediators of protection against the blood stages of the infection, but few studies have investigated this in the context of mAbs. We aimed to isolate mAbs agnostic to cognate antigens that target whole merozoites and simultaneously induce potent neutrophil activity measured by the level of reactive oxygen species (ROS) production using an antibody-dependent respiratory burst (ADRB) assay. Methods We used samples from semi-immune adults living in coastal Kenya to isolate mAbs that induce merozoite-specific ADRB activity. We then tested whether modifying the expressed IgG1 isotype to an IgG-IgA Fc region chimera would enhance the level of ADRB activity. Results We isolated a panel of nine mAbs with specificity to whole merozoites. mAb J31 induced ADRB activity in a dose-dependent fashion. Compared to IgG1, our modified antibody IgG-IgA bi-isotype induced higher ADRB activity across all concentrations tested. Further, we observed a negative hook effect at high IgG1 mAb concentrations (i.e., >200 µg/mL), but this was reversed by Fc modification. We identified MSP3.5 as the potential cognate target of mAb J31. Conclusions We demonstrate an approach to engineer mAbs with enhanced ADRB potency against blood-stage parasites.
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Affiliation(s)
- Rodney Ogwang
- Centre for Geographic Medicine Research (Coast), Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
- College of Health Sciences, Makerere University, Kampala, Uganda
| | - Lewis Murugu
- Centre for Geographic Medicine Research (Coast), Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
- Department of Biological Sciences, Pwani University, Kilifi, Kenya
| | - Irene N. Nkumama
- Centre of Infectious Diseases, Heidelberg University Hospital, Heidelberg, Germany
| | - Lydia Nyamako
- Centre for Geographic Medicine Research (Coast), Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Oscar Kai
- Centre for Geographic Medicine Research (Coast), Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Kennedy Mwai
- Centre for Geographic Medicine Research (Coast), Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Linda Murungi
- Centre for Geographic Medicine Research (Coast), Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Richard Idro
- College of Health Sciences, Makerere University, Kampala, Uganda
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Philip Bejon
- Centre for Geographic Medicine Research (Coast), Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
| | - James Tuju
- Centre for Geographic Medicine Research (Coast), Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
- Department of Biological Sciences, Pwani University, Kilifi, Kenya
| | - Sam Muchina Kinyanjui
- Centre for Geographic Medicine Research (Coast), Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Faith H. A. Osier
- Department of Life Sciences, Imperial College London, London, United Kingdom
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2
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Faber BW, Yeoh LM, Kurtovic L, Mol WEM, Poelert M, Smits E, Rodriguez Garcia R, Mandalawi-Van der Eijk M, van der Werff N, Voorberg-van der Wel A, Remarque EJ, Beeson JG, Kocken CHM. A Diversity Covering (DiCo) Plasmodium vivax apical membrane antigen-1 vaccine adjuvanted with RFASE/RSL10 yields high levels of growth-inhibitory antibodies. Vaccine 2024; 42:1785-1792. [PMID: 38365484 DOI: 10.1016/j.vaccine.2024.02.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 01/10/2024] [Accepted: 02/07/2024] [Indexed: 02/18/2024]
Abstract
Plasmodium vivax malaria is increasingly recognized as a major global health problem and the socio-economic impact of P.vivax-induced burden is huge. Vaccine development against P. vivax malaria has been hampered by the lack of an in vitro culture system and poor access to P. vivax sporozoites. The recent generation of Plasmodium falciparum parasites that express a functional P. vivax AMA1 molecule has provided a platform for in vitro evaluation of PvAMA1 as a potential blood stage vaccine. Three so-called PvAMA1 Diversity Covering (DiCo) proteins were designed to assess their potential to induce a functional and broad humoral immune response to the polymorphic PvAMA1 molecule. Rabbits were immunized with the mixture of three, Pichia-produced, PvAMA1 DiCo proteins, as well as with 2 naturally occurring PvAMA1 alleles. For these three groups, the experimental adjuvant raffinose fatty acid sulfate ester (RFASE) was used, while in a fourth group the purified main mono-esterified constituent (RSL10) of this adjuvant was used. Animals immunized with the mixture of the three PvAMA1 DiCo proteins in RFASE showed high anti-PvAMA1 antibody titers against three naturally occurring PvAMA1variants while also high growth-inhibitory capacity was observed against P. falciparum parasites expressing PvAMA1. This supports further clinical development of the PvAMA1 DiCo mixture as a potential malaria vaccine. However, as the single allele PvAMA1 SalI-group showed similar characteristics in antibody titer and inhibition levels as the PvAMA1 DiCo mixture-group, this raises the question whether a mixture is really necessary to overcome the polymorphism in the vaccine candidate. RFASE induced strong humoral responses, as did the animals immunized with the purified component, RSL10. This suggests that RSL10 is the active ingredient. However, one of the RSL10-immunized animal showed a delayed response, necessitating further research into the clinical development of RSL10.
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Affiliation(s)
- Bart W Faber
- Department of Parasitology, Biomedical Primate Research Centre, Rijswijk, the Netherlands.
| | - Lee M Yeoh
- Burnet Institute, Melbourne, Victoria, Australia; Department of Medicine, The University of Melbourne, Victoria, Australia
| | - Liriye Kurtovic
- Burnet Institute, Melbourne, Victoria, Australia; Central Clinical School and Department of Microbiology, Monash University, Victoria, Australia
| | | | | | | | | | | | - Nicole van der Werff
- Department of Parasitology, Biomedical Primate Research Centre, Rijswijk, the Netherlands
| | | | - Edmond J Remarque
- Department of Virology, Biomedical Primate Research Centre, Rijswijk, the Netherlands
| | - James G Beeson
- Burnet Institute, Melbourne, Victoria, Australia; Central Clinical School and Department of Microbiology, Monash University, Victoria, Australia; Department of Infectious Diseases, University of Melbourne, Victoria, Australia
| | - Clemens H M Kocken
- Department of Parasitology, Biomedical Primate Research Centre, Rijswijk, the Netherlands
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3
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Lima C, Verdaguer IB, Wunderlich G, Katzin AM, Crabb BS, Gilson PR, Azevedo MF. Conditional expression of NanoLuc luciferase through a multimodular system offers rapid detection of antimalarial drug activity. Exp Parasitol 2023; 254:108620. [PMID: 37716462 DOI: 10.1016/j.exppara.2023.108620] [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: 04/28/2023] [Revised: 09/06/2023] [Accepted: 09/12/2023] [Indexed: 09/18/2023]
Abstract
Conditional gene expression is a powerful tool to investigate putative vaccine and drug targets, especially in a haploid organism such as Plasmodium falciparum. Inducible systems based on regulation of either transcription, translation, protein or mRNA stability, among others, allow switching on an off the expression of any desired gene causing specific gain or loss of function phenotypes. However, those systems can be cumbersome involving the construction of large plasmids and generation of multiple transgenic parasite lines. In addition, the dynamic range of regulation achieved is not predictable for each individual gene and can be insufficient to generate detectable phenotypes when the genes of interest are silenced. Here, we combined up to three distinct inducible systems to regulate the expression of a single gene. Expression of the reporter NanoLuc luciferase was regulated over 40-fold, which correlates to the regulation achieved by each individual system multiplied by each other. We applied the conditionally expressed NanoLuc to evaluate the effect of fast-acting antimalarials such as chloroquine and artesunate as well as of slower-acting ones such as atovaquone. The conditionally expressed reporter allowed faster and more reliable detection of toxicity to the parasite, which correlated to the expected action of each compound. Bioluminescence achieved by the expression of this inducible highly sensitive reporter is therefore a promising tool to investigate the temporal effect of potential new antimalarials. This single plasmid combination system might also prove useful to achieve sufficient regulation of genes of interest to produce loss-of-function phenotypes.
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Affiliation(s)
- Caroline Lima
- Federal University of Sao Paulo, Santos, Sao Paulo, Brazil
| | - Ignasi B Verdaguer
- Departamento de Parasitologia, Instituto de Ciência Biomédicas, Universidade de São Paulo, Avenida Prof. Lineu Prestes, 1374, São Paulo, SP, 05508-900, Brazil
| | - Gerhard Wunderlich
- Departamento de Parasitologia, Instituto de Ciência Biomédicas, Universidade de São Paulo, Avenida Prof. Lineu Prestes, 1374, São Paulo, SP, 05508-900, Brazil
| | - Alejandro M Katzin
- Departamento de Parasitologia, Instituto de Ciência Biomédicas, Universidade de São Paulo, Avenida Prof. Lineu Prestes, 1374, São Paulo, SP, 05508-900, Brazil
| | - Brendan S Crabb
- Burnet Institute, Melbourne, VIC, 3004, Australia; University of Melbourne, VIC, 3052, Australia; Monash University, Melbourne, VIC, 3004, Australia
| | - Paul R Gilson
- Burnet Institute, Melbourne, VIC, 3004, Australia; University of Melbourne, VIC, 3052, Australia
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4
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Feldman TP, Ryan Y, Egan ES. Plasmodium falciparum infection of human erythroblasts induces transcriptional changes associated with dyserythropoiesis. Blood Adv 2023; 7:5496-5509. [PMID: 37493969 PMCID: PMC10515311 DOI: 10.1182/bloodadvances.2023010844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 07/24/2023] [Accepted: 07/24/2023] [Indexed: 07/27/2023] Open
Abstract
During development down the erythroid lineage, hematopoietic stem cells undergo dramatic changes to cellular morphology and function in response to a complex and tightly regulated program of gene expression. In malaria infection, Plasmodium spp parasites accumulate in the bone marrow parenchyma, and emerging evidence suggests erythroblastic islands are a protective site for parasite development into gametocytes. Although it has been observed that Plasmodium falciparum infection in late-stage erythroblasts can delay terminal erythroid differentiation and enucleation, the mechanism(s) underlying this phenomenon are unknown. Here, we apply RNA sequencing after fluorescence-activated cell sorting of infected erythroblasts to identify transcriptional responses to direct and indirect interaction with P falciparum. Four developmental stages of erythroid cells were analyzed: proerythroblast, basophilic erythroblast, polychromatic erythroblast, and orthochromatic erythroblast. We found extensive transcriptional changes in infected erythroblasts compared with that in uninfected cells in the same culture, including dysregulation of genes involved in erythroid proliferation and developmental processes. Although some indicators of cellular oxidative and proteotoxic stress were common across all stages of erythropoiesis, many responses were specific to cellular processes associated with developmental stage. Together, our results evidence multiple possible avenues by which parasite infection can induce dyserythropoiesis at specific points along the erythroid continuum, advancing our understanding of the molecular determinants of malaria anemia.
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Affiliation(s)
- Tamar P. Feldman
- Department of Pediatrics, Stanford University School of Medicine, Stanford, CA
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA
| | - Yana Ryan
- Stanford Center for Genomics and Personalized Medicine, Stanford University School of Medicine, Stanford, CA
| | - Elizabeth S. Egan
- Department of Pediatrics, Stanford University School of Medicine, Stanford, CA
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA
- Chan Zuckerberg Biohub, San Francisco, CA
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5
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Weiss GE, Ragotte RJ, Quinkert D, Lias AM, Dans MG, Boulet C, Looker O, Ventura OD, Williams BG, Crabb BS, Draper SJ, Gilson PR. The dual action of human antibodies specific to Plasmodium falciparum PfRH5 and PfCyRPA: Blocking invasion and inactivating extracellular merozoites. PLoS Pathog 2023; 19:e1011182. [PMID: 37713419 PMCID: PMC10529537 DOI: 10.1371/journal.ppat.1011182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 09/27/2023] [Accepted: 08/29/2023] [Indexed: 09/17/2023] Open
Abstract
The Plasmodium falciparum reticulocyte-binding protein homolog 5 (PfRH5) is the current leading blood-stage malaria vaccine candidate. PfRH5 functions as part of the pentameric PCRCR complex containing PTRAMP, CSS, PfCyRPA and PfRIPR, all of which are essential for infection of human red blood cells (RBCs). To trigger RBC invasion, PfRH5 engages with RBC protein basigin in a step termed the RH5-basigin binding stage. Although we know increasingly more about how antibodies specific for PfRH5 can block invasion, much less is known about how antibodies recognizing other members of the PCRCR complex can inhibit invasion. To address this, we performed live cell imaging using monoclonal antibodies (mAbs) which bind PfRH5 and PfCyRPA. We measured the degree and timing of the invasion inhibition, the stage at which it occurred, as well as subsequent events. We show that parasite invasion is blocked by individual mAbs, and the degree of inhibition is enhanced when combining a mAb specific for PfRH5 with one binding PfCyRPA. In addition to directly establishing the invasion-blocking capacity of the mAbs, we identified a secondary action of certain mAbs on extracellular parasites that had not yet invaded where the mAbs appeared to inactivate the parasites by triggering a developmental pathway normally only seen after successful invasion. These findings suggest that epitopes within the PfCyRPA-PfRH5 sub-complex that elicit these dual responses may be more effective immunogens than neighboring epitopes by both blocking parasites from invading and rapidly inactivating extracellular parasites. These two protective mechanisms, prevention of invasion and inactivation of uninvaded parasites, resulting from antibody to a single epitope indicate a possible route to the development of more effective vaccines.
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Affiliation(s)
- Greta E. Weiss
- Burnet Institute, 85 Commercial Road, Melbourne, Victoria, Australia
| | - Robert J. Ragotte
- Department of Biochemistry, University of Oxford, Dorothy Crowfoot Hodgkin Building, Oxford, United Kingdom
| | - Doris Quinkert
- Department of Biochemistry, University of Oxford, Dorothy Crowfoot Hodgkin Building, Oxford, United Kingdom
- Kavli Institute for Nanoscience Discovery, University of Oxford, Dorothy Crowfoot Hodgkin Building, Oxford, United Kingdom
| | - Amelia M. Lias
- Department of Biochemistry, University of Oxford, Dorothy Crowfoot Hodgkin Building, Oxford, United Kingdom
- Kavli Institute for Nanoscience Discovery, University of Oxford, Dorothy Crowfoot Hodgkin Building, Oxford, United Kingdom
| | - Madeline G. Dans
- Burnet Institute, 85 Commercial Road, Melbourne, Victoria, Australia
| | - Coralie Boulet
- Burnet Institute, 85 Commercial Road, Melbourne, Victoria, Australia
| | - Oliver Looker
- Burnet Institute, 85 Commercial Road, Melbourne, Victoria, Australia
| | - Olivia D. Ventura
- Burnet Institute, 85 Commercial Road, Melbourne, Victoria, Australia
| | - Barnabas G. Williams
- Department of Biochemistry, University of Oxford, Dorothy Crowfoot Hodgkin Building, Oxford, United Kingdom
- Kavli Institute for Nanoscience Discovery, University of Oxford, Dorothy Crowfoot Hodgkin Building, Oxford, United Kingdom
| | - Brendan S. Crabb
- Burnet Institute, 85 Commercial Road, Melbourne, Victoria, Australia
- The University of Melbourne, Grattan Street, Parkville, Victoria, Australia
| | - Simon J. Draper
- Department of Biochemistry, University of Oxford, Dorothy Crowfoot Hodgkin Building, Oxford, United Kingdom
- Kavli Institute for Nanoscience Discovery, University of Oxford, Dorothy Crowfoot Hodgkin Building, Oxford, United Kingdom
| | - Paul R. Gilson
- Burnet Institute, 85 Commercial Road, Melbourne, Victoria, Australia
- The University of Melbourne, Grattan Street, Parkville, Victoria, Australia
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6
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Miyazaki Y, Vos MW, Geurten FJA, Bigeard P, Kroeze H, Yoshioka S, Arisawa M, Inaoka DK, Soulard V, Dechering KJ, Franke-Fayard B, Miyazaki S. A versatile Plasmodium falciparum reporter line expressing NanoLuc enables highly sensitive multi-stage drug assays. Commun Biol 2023; 6:713. [PMID: 37438491 DOI: 10.1038/s42003-023-05078-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Accepted: 06/27/2023] [Indexed: 07/14/2023] Open
Abstract
Transgenic luciferase-expressing Plasmodium falciparum parasites have been widely used for the evaluation of anti-malarial compounds. Here, to screen for anti-malarial drugs effective against multiple stages of the parasite, we generate a P. falciparum reporter parasite that constitutively expresses NanoLuciferase (NanoLuc) throughout its whole life cycle. The NanoLuc-expressing P. falciparum reporter parasite shows a quantitative NanoLuc signal in the asexual blood, gametocyte, mosquito, and liver stages. We also establish assay systems to evaluate the anti-malarial activity of compounds at the asexual blood, gametocyte, and liver stages, and then determine the 50% inhibitory concentration (IC50) value of several anti-malarial compounds. Through the development of this robust high-throughput screening system, we identify an anti-malarial compound that kills the asexual blood stage parasites. Our study highlights the utility of the NanoLuc reporter line, which may advance anti-malarial drug development through the improved screening of compounds targeting the human malarial parasite at multiple stages.
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Affiliation(s)
- Yukiko Miyazaki
- Department of Molecular Infection Dynamics, Institute of Tropical Medicine (NEKKEN), Nagasaki University, 852-8523, Nagasaki, Japan.
- Department of Parasitology, Leiden University Medical Center, 2333 ZA, Leiden, The Netherlands.
- Department of Protozoology, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan.
| | - Martijn W Vos
- TropIQ Health Sciences, Transistorweg 5, 6534 AT, Nijmegen, The Netherlands
| | - Fiona J A Geurten
- Department of Parasitology, Leiden University Medical Center, 2333 ZA, Leiden, The Netherlands
| | - Pierre Bigeard
- Sorbonne Université, Inserm, CNRS, Centre d'Immunologie et des Maladies Infectieuses, CIMI-Paris, F-75013, Paris, France
| | - Hans Kroeze
- Department of Parasitology, Leiden University Medical Center, 2333 ZA, Leiden, The Netherlands
| | - Shohei Yoshioka
- Graduate School of Pharmaceutical Sciences, Osaka University, 565-0871, Osaka, Japan
| | - Mitsuhiro Arisawa
- Graduate School of Pharmaceutical Sciences, Osaka University, 565-0871, Osaka, Japan
| | - Daniel Ken Inaoka
- Department of Molecular Infection Dynamics, Institute of Tropical Medicine (NEKKEN), Nagasaki University, 852-8523, Nagasaki, Japan
- School of Tropical Medicine and Global Health, Nagasaki University, Nagasaki, 852-8523, Japan
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Tokyo, 113-0033, Japan
| | - Valerie Soulard
- Sorbonne Université, Inserm, CNRS, Centre d'Immunologie et des Maladies Infectieuses, CIMI-Paris, F-75013, Paris, France
| | - Koen J Dechering
- TropIQ Health Sciences, Transistorweg 5, 6534 AT, Nijmegen, The Netherlands
| | - Blandine Franke-Fayard
- Department of Parasitology, Leiden University Medical Center, 2333 ZA, Leiden, The Netherlands
| | - Shinya Miyazaki
- Department of Parasitology, Leiden University Medical Center, 2333 ZA, Leiden, The Netherlands.
- Department of Cellular Architecture Studies, Institute of Tropical Medicine (NEKKEN), Nagasaki University, 852-8523, Nagasaki, Japan.
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7
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Feldman TP, Ryan Y, Egan ES. Plasmodium falciparum infection of human erythroblasts induces transcriptional changes associated with dyserythropoiesis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.23.538003. [PMID: 37398027 PMCID: PMC10312461 DOI: 10.1101/2023.04.23.538003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
During development down the erythroid lineage, hematopoietic stem cells undergo dramatic changes to cellular morphology and function in response to a complex and tightly regulated program of gene expression. In malaria infection, Plasmodium spp . parasites accumulate in the bone marrow parenchyma, and emerging evidence suggests erythroblastic islands are a protective site for parasite development into gametocytes. While it has been observed that Plasmodium falciparum infection of late-stage erythroblasts can delay terminal erythroid differentiation and enucleation, the mechanism(s) underlying this phenomenon are unknown. Here, we apply RNA-seq after fluorescence-activated cell sorting (FACS) of infected erythroblasts to identify transcriptional responses to direct and indirect interaction with Plasmodium falciparum . Four developmental stages of erythroid cells were analyzed: proerythroblast, basophilic erythroblast, polychromatic erythroblast, and orthochromatic erythroblast. We found extensive transcriptional changes in infected erythroblasts compared to uninfected cells in the same culture, including dysregulation of genes involved in erythroid proliferation and developmental processes. Whereas some indicators of cellular oxidative and proteotoxic stress were common across all stages of erythropoiesis, many responses were specific to cellular processes associated with developmental stage. Together, our results evidence multiple possible avenues by which parasite infection can induce dyserythropoiesis at specific points along the erythroid continuum, advancing our understanding of the molecular determinants of malaria anemia. Key Points Erythroblasts at different stages of differentiation have distinct responses to infection by Plasmodium falciparum . P. falciparum infection of erythroblasts alters expression of genes related to oxidative and proteotoxic stress and erythroid development.
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8
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Fotoran WL, Silva JRD, Glitz C, Ferreira LCDS, Wunderlich G. Establishment of an Antiplasmodial Vaccine Based on PfRH5-Encoding RNA Replicons Stabilized by Cationic Liposomes. Pharmaceutics 2023; 15:pharmaceutics15041223. [PMID: 37111706 PMCID: PMC10145066 DOI: 10.3390/pharmaceutics15041223] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 04/03/2023] [Accepted: 04/06/2023] [Indexed: 04/29/2023] Open
Abstract
BACKGROUND Nucleic acid-based vaccines have been studied for the past four decades, but the approval of the first messenger RNA (mRNA) vaccines during the COVID-19 pandemic opened renewed perspectives for the development of similar vaccines against different infectious diseases. Presently available mRNA vaccines are based on non-replicative mRNA, which contains modified nucleosides encased in lipid vesicles, allowing for entry into the host cell cytoplasm, and reducing inflammatory reactions. An alternative immunization strategy employs self-amplifying mRNA (samRNA) derived from alphaviruses, but lacks viral structural genes. Once incorporated into ionizable lipid shells, these vaccines lead to enhanced gene expression, and lower mRNA doses are required to induce protective immune responses. In the present study, we tested a samRNA vaccine formulation based on the SP6 Venezuelan equine encephalitis (VEE) vector incorporated into cationic liposomes (dimethyldioctadecyl ammonium bromide and a cholesterol derivative). Three vaccines were generated that encoded two reporter genes (GFP and nanoLuc) and the Plasmodium falciparum reticulocyte binding protein homologue 5 (PfRH5). METHODS Transfection assays were performed using Vero and HEK293T cells, and the mice were immunized via the intradermal route using a tattooing device. RESULTS The liposome-replicon complexes showed high transfection efficiencies with in vitro cultured cells, whereas tattooing immunization with GFP-encoding replicons demonstrated gene expression in mouse skin up to 48 h after immunization. Mice immunized with liposomal PfRH5-encoding RNA replicons elicited antibodies that recognized the native protein expressed in P. falciparum schizont extracts, and inhibited the growth of the parasite in vitro. CONCLUSION Intradermal delivery of cationic lipid-encapsulated samRNA constructs is a feasible approach for developing future malaria vaccines.
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Affiliation(s)
- Wesley L Fotoran
- Department of Parasitology, Institute for Biomedical Sciences, University of São Paulo, Avenida Professor Lineu Prestes 1374, São Paulo 05508-000, SP, Brazil
| | - Jamile Ramos da Silva
- Department of Microbiology, Institute for Biomedical Sciences, University of São Paulo, Avenida Professor Lineu Prestes 1374, São Paulo 05508-000, SP, Brazil
| | - Christiane Glitz
- Department of Molecular Physiology, Institute of Animal Physiology, Westfälische Wilhelms University of Münster, 48149 Münster, Germany
| | - Luís Carlos de Souza Ferreira
- Department of Microbiology, Institute for Biomedical Sciences, University of São Paulo, Avenida Professor Lineu Prestes 1374, São Paulo 05508-000, SP, Brazil
- Scientific Platform Pasteur-USP, University of São Paulo, Avenida Lucio Martins Rodrigues 370, São Paulo 05508-020, SP, Brazil
| | - Gerhard Wunderlich
- Department of Parasitology, Institute for Biomedical Sciences, University of São Paulo, Avenida Professor Lineu Prestes 1374, São Paulo 05508-000, SP, Brazil
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9
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Defining species-specific and conserved interactions of apical membrane protein 1 during erythrocyte invasion in malaria to inform multi-species vaccines. Cell Mol Life Sci 2023; 80:74. [PMID: 36847896 PMCID: PMC9969379 DOI: 10.1007/s00018-023-04712-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 01/17/2023] [Accepted: 01/30/2023] [Indexed: 03/01/2023]
Abstract
Plasmodium falciparum and P. vivax are the major causes of human malaria, and P. knowlesi is an important additional cause in SE Asia. Binding of apical membrane antigen 1 (AMA1) to rhoptry neck protein 2 (RON2) was thought to be essential for merozoite invasion of erythrocytes by Plasmodium spp. Our findings reveal that P. falciparum and P. vivax have diverged and show species-specific binding of AMA1 to RON2, determined by a β-hairpin loop in RON2 and specific residues in AMA1 Loop1E. In contrast, cross-species binding of AMA1 to RON2 is retained between P. vivax and P. knowlesi. Mutation of specific amino acids in AMA1 Loop1E in P. falciparum or P. vivax ablated RON2 binding without impacting erythrocyte invasion. This indicates that the AMA1-RON2-loop interaction is not essential for invasion and additional AMA1 interactions are involved. Mutations in AMA1 that disrupt RON2 binding also enable escape of invasion inhibitory antibodies. Therefore, vaccines and therapeutics will need to be broader than targeting only the AMA1-RON2 interaction. Antibodies targeting AMA1 domain 3 had greater invasion-inhibitory activity when RON2-loop binding was ablated, suggesting this domain is a promising additional target for vaccine development. Targeting multiple AMA1 interactions involved in invasion may enable vaccines that generate more potent inhibitory antibodies and address the capacity for immune evasion. Findings on specific residues for invasion function and species divergence and conservation can inform novel vaccines and therapeutics against malaria caused by three species, including the potential for cross-species vaccines.
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10
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Burns AL, Sleebs BE, Gancheva M, McLean KT, Siddiqui G, Venter H, Beeson JG, O’Handley R, Creek DJ, Ma S, Frölich S, Goodman CD, McFadden GI, Wilson DW. Targeting malaria parasites with novel derivatives of azithromycin. Front Cell Infect Microbiol 2022; 12:1063407. [PMID: 36530422 PMCID: PMC9748569 DOI: 10.3389/fcimb.2022.1063407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Accepted: 11/09/2022] [Indexed: 12/02/2022] Open
Abstract
Introduction The spread of artemisinin resistant Plasmodium falciparum parasites is of global concern and highlights the need to identify new antimalarials for future treatments. Azithromycin, a macrolide antibiotic used clinically against malaria, kills parasites via two mechanisms: 'delayed death' by inhibiting the bacterium-like ribosomes of the apicoplast, and 'quick-killing' that kills rapidly across the entire blood stage development. Methods Here, 22 azithromycin analogues were explored for delayed death and quick-killing activities against P. falciparum (the most virulent human malaria) and P. knowlesi (a monkey parasite that frequently infects humans). Results Seventeen analogues showed improved quick-killing against both Plasmodium species, with up to 38 to 20-fold higher potency over azithromycin after less than 48 or 28 hours of treatment for P. falciparum and P. knowlesi, respectively. Quick-killing analogues maintained activity throughout the blood stage lifecycle, including ring stages of P. falciparum parasites (<12 hrs treatment) and were >5-fold more selective against P. falciparum than human cells. Isopentenyl pyrophosphate supplemented parasites that lacked an apicoplast were equally sensitive to quick-killing analogues, confirming that the quick killing activity of these drugs was not directed at the apicoplast. Further, activity against the related apicoplast containing parasite Toxoplasma gondii and the gram-positive bacterium Streptococcus pneumoniae did not show improvement over azithromycin, highlighting the specific improvement in antimalarial quick-killing activity. Metabolomic profiling of parasites subjected to the most potent compound showed a build-up of non-haemoglobin derived peptides that was similar to chloroquine, while also exhibiting accumulation of haemoglobin-derived peptides that was absent for chloroquine treatment. Discussion The azithromycin analogues characterised in this study expand the structural diversity over previously reported quick-killing compounds and provide new starting points to develop azithromycin analogues with quick-killing antimalarial activity.
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Affiliation(s)
- Amy L. Burns
- Research Centre for Infectious Diseases, School of Biological Sciences, the University of Adelaide, Adelaide, SA, Australia,School of Science and Technology, the University of New England, Armidale, NSW, Australia
| | - Brad E. Sleebs
- ACRF Chemical Biology Division, Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia,Department of Medical Biology, University of Melbourne, Parkville, VIC, Australia
| | - Maria Gancheva
- Research Centre for Infectious Diseases, School of Biological Sciences, the University of Adelaide, Adelaide, SA, Australia
| | - Kimberley T. McLean
- Research Centre for Infectious Diseases, School of Biological Sciences, the University of Adelaide, Adelaide, SA, Australia
| | - Ghizal Siddiqui
- Drug Delivery Disposition and Dynamics, Monash University, Parkville, VIC, Australia
| | - Henrietta Venter
- Health and Biomedical Innovation, Clinical and Health Sciences, University of South Australia, Adelaide, SA, Australia
| | - James G. Beeson
- Healthy Mothers, Healthy Babies Program, Burnet Institute, Melbourne, VIC, Australia,Department of Medicine, University of Melbourne, Parkville, VIC, Australia,Central Clinical School, Monash University, Melbourne, Vic, Australia,Department of Microbiology, Monash University, Melbourne, Vic, Australia
| | - Ryan O’Handley
- School of Animal and Veterinary Science, University of Adelaide, Adelaide, SA, Australia,Australian Centre for Antimicrobial Resistance Ecology, The University of Adelaide, Adelaide, SA, Australia
| | - Darren J. Creek
- Drug Delivery Disposition and Dynamics, Monash University, Parkville, VIC, Australia
| | - Shutao Ma
- Department of Medicinal Chemistry, Key Laboratory of Chemical Biology, Ministry of Education, School of Pharmaceutical Sciences, Shandong University, Jinan, China
| | - Sonja Frölich
- Research Centre for Infectious Diseases, School of Biological Sciences, the University of Adelaide, Adelaide, SA, Australia
| | | | | | - Danny W. Wilson
- Research Centre for Infectious Diseases, School of Biological Sciences, the University of Adelaide, Adelaide, SA, Australia,Healthy Mothers, Healthy Babies Program, Burnet Institute, Melbourne, VIC, Australia,Australian Centre for Antimicrobial Resistance Ecology, The University of Adelaide, Adelaide, SA, Australia,*Correspondence: Danny W. Wilson,
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11
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In vitro cultivation methods for coccidian parasite research. Int J Parasitol 2022:S0020-7519(22)00153-9. [DOI: 10.1016/j.ijpara.2022.10.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 09/29/2022] [Accepted: 10/09/2022] [Indexed: 11/17/2022]
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12
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Hoshizaki J, Jagoe H, Lee MCS. Efficient generation of mNeonGreen Plasmodium falciparum reporter lines enables quantitative fitness analysis. Front Cell Infect Microbiol 2022; 12:981432. [PMID: 36189342 PMCID: PMC9523114 DOI: 10.3389/fcimb.2022.981432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 08/30/2022] [Indexed: 11/13/2022] Open
Abstract
CRISPR editing has enabled the rapid creation of fluorescent Plasmodium transgenic lines, facilitating a deeper understanding of parasite biology. The impact of genetic perturbations such as gene disruption or the introduction of drug resistance alleles on parasite fitness is typically quantified in competitive growth assays between the query line and a wild type reference. Although fluorescent reporter lines offer a facile and frequently used method to measure relative growth, this approach is limited by the strain background of the existing reporter, which may not match the growth characteristics of the query strains, particularly if these are slower-growing field isolates. Here, we demonstrate an efficient CRISPR-based approach to generate fluorescently labelled parasite lines using mNeonGreen derived from the LanYFP protein in Branchiostoma lanceolatum, which is one of the brightest monomeric green fluorescent proteins identified. Using a positive-selection approach by insertion of an in-frame blasticidin S deaminase marker, we generated a Dd2 reporter line expressing mNeonGreen under the control of the pfpare (P. falciparum Prodrug Activation and Resistance Esterase) locus. We selected the pfpare locus as an integration site because it is highly conserved across P. falciparum strains, expressed throughout the intraerythrocytic cycle, not essential, and offers the potential for negative selection to further enrich for integrants. The mNeonGreen@pare line demonstrates strong fluorescence with a negligible fitness defect. In addition, the construct developed can serve as a tool to fluorescently tag other P. falciparum strains for in vitro experimentation.
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13
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Cell biological analysis reveals an essential role for Pfcerli2 in erythrocyte invasion by malaria parasites. Commun Biol 2022; 5:121. [PMID: 35140336 PMCID: PMC8828742 DOI: 10.1038/s42003-022-03020-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Accepted: 12/23/2021] [Indexed: 01/01/2023] Open
Abstract
Merozoite invasion of host red blood cells (RBCs) is essential for survival of the human malaria parasite Plasmodium falciparum. Proteins involved with RBC binding and invasion are secreted from dual-club shaped organelles at the apical tip of the merozoite called the rhoptries. Here we characterise P. falciparum Cytosolically Exposed Rhoptry Leaflet Interacting protein 2 (PfCERLI2), as a rhoptry bulb protein that is essential for merozoite invasion. Phylogenetic analyses show that cerli2 arose through an ancestral gene duplication of cerli1. We show that PfCERLI2 is essential for blood-stage growth and localises to the cytosolic face of the rhoptry bulb. Inducible knockdown of PfCERLI2 led to a proportion of merozoites failing to invade and was associated with elongation of the rhoptry organelle during merozoite development and inhibition of rhoptry antigen processing. These findings identify PfCERLI2 as a protein that has key roles in rhoptry biology during merozoite invasion. Benjamin Liffner and Miguel Balbin et al. report that the Plasmodium falciparum protein, PfCERLI2, localises to the cytosolic face of the parasite’s rhoptry bulb and is essential for invasion and growth within human red blood cells.
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14
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Bioactive Constituents and Potency of Aqueous-Methanolic Extract of <i>Asclepias syriaca</i> on <i>Plasmodium falciparum </i>Infected Albino Rats. JOURNAL OF BIOMIMETICS BIOMATERIALS AND BIOMEDICAL ENGINEERING 2021. [DOI: 10.4028/www.scientific.net/jbbbe.51.15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
High mortality rate couple with the economic effect of deadly Plasmodium falciparum caused by malaria necessitated this study. Evaluation of bioactive constituents and antimalarial properties of the aqueous-methanolic extract of Asclepias syriaca (A. syriaca) was investigated. Bioactive constituents were determined by GC-MS analytical detector. Albino rats were five in each group of six groups (A-E) in which group A was non-infected with P. falciparum (negative control). Groups B, C, D, E were infected with 1×107/ml P. falciparum without treated, treated with standard drugs of 20mg of chloroquine/kg, 100, 200 and 400mg of extracted A. syriaca/kg, respectively. Hematological and biochemical parameters of Plasmodium falciparum infected albino rats were determined. Aqueous-methanolic extract of A. syriaca leaf made up of high content of pyrimidine, quinolone and silane derivatives with synergetic properties with potency for therapeutic of malarial and viral infectious diseases. MCV, PLA, RBC, total protein and albumin were significantly elevated upon infected P. falciparum and gradually increases with dosage and time when treated with chloroquine and A.syriaca leaf extract but vice visa for the case WBC and creatinine. Parasitemia level significantly declined when administered with chloroquine and A, syriaca leaf extract for 36 hours. Hence serves as an effective medication in place of chloroquine due to its availability, avoidable and as a source of relevant medications to Plasmodium spp and viral infectious diseases.
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15
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Nguyen W, Dans MG, Ngo A, Gancheva MR, Romeo O, Duffy S, de Koning-Ward TF, Lowes KN, Sabroux HJ, Avery VM, Wilson DW, Gilson PR, Sleebs BE. Structure activity refinement of phenylsulfonyl piperazines as antimalarials that block erythrocytic invasion. Eur J Med Chem 2021; 214:113253. [PMID: 33610028 DOI: 10.1016/j.ejmech.2021.113253] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 01/12/2021] [Accepted: 01/29/2021] [Indexed: 12/19/2022]
Abstract
The emerging resistance to combination therapies comprised of artemisinin derivatives has driven a need to identify new antimalarials with novel mechanisms of action. Central to the survival and proliferation of the malaria parasite is the invasion of red blood cells by Plasmodium merozoites, providing an attractive target for novel therapeutics. A screen of the Medicines for Malaria Venture Pathogen Box employing transgenic P. falciparum parasites expressing the nanoluciferase bioluminescent reporter identified the phenylsulfonyl piperazine class as a specific inhibitor of erythrocyte invasion. Here, we describe the optimization and further characterization of the phenylsulfonyl piperazine class. During the optimization process we defined the functionality required for P. falciparum asexual stage activity and determined the alpha-carbonyl S-methyl isomer was important for antimalarial potency. The optimized compounds also possessed comparable activity against multidrug resistant strains of P. falciparum and displayed weak activity against sexual stage gametocytes. We determined that the optimized compounds blocked erythrocyte invasion consistent with the asexual activity observed and therefore the phenylsulfonyl piperazine analogues described could serve as useful tools for studying Plasmodium erythrocyte invasion.
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Affiliation(s)
- William Nguyen
- The Walter and Eliza Hall Institute of Medical Research, Parkville, 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville, 3010, Australia
| | - Madeline G Dans
- Macfarlane Burnet Institute for Medical Research and Public Health, Melbourne, 3004, Australia; School of Medicine, Deakin University, Waurn Ponds, 3216, Australia
| | - Anna Ngo
- The Walter and Eliza Hall Institute of Medical Research, Parkville, 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville, 3010, Australia
| | - Maria R Gancheva
- Research Centre for Infectious Diseases, School of Biological Sciences, University of Adelaide, Adelaide, Australia
| | - Ornella Romeo
- Research Centre for Infectious Diseases, School of Biological Sciences, University of Adelaide, Adelaide, Australia
| | - Sandra Duffy
- Discovery Biology, Griffith University, Nathan, Queensland, 4111, Australia
| | | | - Kym N Lowes
- The Walter and Eliza Hall Institute of Medical Research, Parkville, 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville, 3010, Australia
| | - Helene Jousset Sabroux
- The Walter and Eliza Hall Institute of Medical Research, Parkville, 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville, 3010, Australia
| | - Vicky M Avery
- Discovery Biology, Griffith University, Nathan, Queensland, 4111, Australia
| | - Danny W Wilson
- Research Centre for Infectious Diseases, School of Biological Sciences, University of Adelaide, Adelaide, Australia; Macfarlane Burnet Institute for Medical Research and Public Health, Melbourne, 3004, Australia
| | - Paul R Gilson
- Macfarlane Burnet Institute for Medical Research and Public Health, Melbourne, 3004, Australia
| | - Brad E Sleebs
- The Walter and Eliza Hall Institute of Medical Research, Parkville, 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville, 3010, Australia.
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16
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Teixeira de Moraes Gomes PA, Veríssimo de Oliveira Cardoso M, Dos Santos IR, Amaro de Sousa F, da Conceição JM, Gouveia de Melo Silva V, Duarte D, Pereira R, Oliveira R, Nogueira F, Alves LC, Brayner FA, da Silva Santos AC, Rêgo Alves Pereira V, Lima Leite AC. Dual Parasiticidal Activities of Phthalimides: Synthesis and Biological Profile against Trypanosoma cruzi and Plasmodium falciparum. ChemMedChem 2020; 15:2164-2175. [PMID: 32813331 DOI: 10.1002/cmdc.202000331] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 08/10/2020] [Indexed: 12/31/2022]
Abstract
Chagas disease and malaria are two neglected tropical diseases (NTDs) that prevail in tropical and subtropical regions in 149 countries. Chagas is also present in Europe, the US and Australia due to immigration of asymptomatic infected individuals. In the absence of an effective vaccine, the control of both diseases relies on chemotherapy. However, the emergence of parasite drug resistance is rendering currently available drugs obsolete. Hence, it is crucial to develop new molecules. Phthalimides, thiosemicarbazones, and 1,3-thiazoles have been used as scaffolds to obtain antiplasmodial and anti-Trypanosoma cruzi agents. Herein we present the synthesis of 24 phthalimido-thiosemicarbazones (3 a-x) and 14 phthalimido-thiazoles (4 a-n) and the corresponding biological activity against T. cruzi, Plasmodium falciparum, and cytotoxicity against mammalian cell lines. Some of these compounds showed potent inhibition of T. cruzi at low cytotoxic concentrations in RAW 264.7 cells. The most active compounds, 3 t (IC50 =3.60 μM), 3 h (IC50 =3.75 μM), and 4 j (IC50 =4.48 μM), were more active than the control drug benznidazole (IC50 =14.6 μM). Overall, the phthalimido-thiosemicarbazone derivatives were more potent than phthalimido-thiazole derivatives against T. cruzi. Flow cytometry assay data showed that compound 4 j was able to induce necrosis and apoptosis in trypomastigotes. Analysis by scanning electron microscopy showed that T. cruzi trypomastigote cells treated with compounds 3 h, 3 t, and 4 j at IC50 concentrations promoted changes in the shape, flagella, and surface of the parasite body similar to those observed in benznidazole-treated cells. The compounds with the highest antimalarial activity were the phthalimido-thiazoles 4 l (IC50 =1.2 μM), 4 m (IC50 =1.7 μM), and 4 n (IC50 =2.4 μM). Together, these data revealed that phthalimido derivatives possess a dual antiparasitic profile with potential effects against T. cruzi and lead-like characteristics.
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Affiliation(s)
| | - Marcos Veríssimo de Oliveira Cardoso
- Laboratório de Prospecção de Moléculas Bioativas Programa de Pós-Graduação em Ciência e Tecnologia Ambiental para o Semiárido, Universidade de Pernambuco, 56328-903, Petrolina, PE, Brazil
| | - Ignes Regina Dos Santos
- Departamento de Ciências Farmacêuticas Centro de Ciências da Saúde, Universidade Federal de Pernambuco, 50740-535, Recife, PE, Brazil
| | - Fabiano Amaro de Sousa
- Departamento de Ciências Farmacêuticas Centro de Ciências da Saúde, Universidade Federal de Pernambuco, 50740-535, Recife, PE, Brazil
| | - Juliana Maria da Conceição
- Departamento de Ciências Farmacêuticas Centro de Ciências da Saúde, Universidade Federal de Pernambuco, 50740-535, Recife, PE, Brazil
| | - Vanessa Gouveia de Melo Silva
- Departamento de Ciências Farmacêuticas Centro de Ciências da Saúde, Universidade Federal de Pernambuco, 50740-535, Recife, PE, Brazil
| | - Denise Duarte
- Unidade de Ensino e Investigação de Parasitologia Médica, Global Health and Tropical Medicine, GHTM, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, UNL, Rua da Junqueira no 100, 1349-008, Lisboa, Portugal
| | - Raquel Pereira
- Unidade de Ensino e Investigação de Parasitologia Médica, Global Health and Tropical Medicine, GHTM, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, UNL, Rua da Junqueira no 100, 1349-008, Lisboa, Portugal
| | - Rafael Oliveira
- Unidade de Ensino e Investigação de Parasitologia Médica, Global Health and Tropical Medicine, GHTM, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, UNL, Rua da Junqueira no 100, 1349-008, Lisboa, Portugal
| | - Fátima Nogueira
- Unidade de Ensino e Investigação de Parasitologia Médica, Global Health and Tropical Medicine, GHTM, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, UNL, Rua da Junqueira no 100, 1349-008, Lisboa, Portugal
| | - Luiz Carlos Alves
- Laboratório de imunopatologia Keizo Asami (LIKA), Campus UFPE, 50670-901, Recife PE, Brazil.,Instituto Aggeu Magalhães, Fundação Oswaldo Cruz, 50670-420, Recife, PE, Brazil
| | - Fabio André Brayner
- Laboratório de imunopatologia Keizo Asami (LIKA), Campus UFPE, 50670-901, Recife PE, Brazil.,Instituto Aggeu Magalhães, Fundação Oswaldo Cruz, 50670-420, Recife, PE, Brazil
| | | | | | - Ana Cristina Lima Leite
- Departamento de Ciências Farmacêuticas Centro de Ciências da Saúde, Universidade Federal de Pernambuco, 50740-535, Recife, PE, Brazil
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17
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Sleebs BE, Jarman KE, Frolich S, Wong W, Healer J, Dai W, Lucet IS, Wilson DW, Cowman AF. Development and application of a high-throughput screening assay for identification of small molecule inhibitors of the P. falciparum reticulocyte binding-like homologue 5 protein. INTERNATIONAL JOURNAL FOR PARASITOLOGY-DRUGS AND DRUG RESISTANCE 2020; 14:188-200. [PMID: 33152623 PMCID: PMC7645381 DOI: 10.1016/j.ijpddr.2020.10.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Revised: 10/21/2020] [Accepted: 10/23/2020] [Indexed: 11/30/2022]
Abstract
The P. falciparum parasite, responsible for the disease in humans known as malaria, must invade erythrocytes to provide an environment for self-replication and survival. For invasion to occur, the parasite must engage several ligands on the host erythrocyte surface to enable adhesion, tight junction formation and entry. Critical interactions include binding of erythrocyte binding-like ligands and reticulocyte binding-like homologues (Rhs) to the surface of the host erythrocyte. The reticulocyte binding-like homologue 5 (Rh5) is the only member of this family that is essential for invasion and it binds to the basigin host receptor. The essential nature of Rh5 makes it an important vaccine target, however to date, Rh5 has not been targeted by small molecule intervention. Here, we describe the development of a high-throughput screening assay to identify small molecules which interfere with the Rh5-basigin interaction. To validate the utility of this assay we screened a known drug library and the Medicines for Malaria Box and demonstrated the reproducibility and robustness of the assay for high-throughput screening purposes. The screen of the known drug library identified the known leukotriene antagonist, pranlukast. We used pranlukast as a model inhibitor in a post screening evaluation cascade. We procured and synthesised analogues of pranlukast to assist in the hit confirmation process and show which structural moieties of pranlukast attenuate the Rh5 – basigin interaction. Evaluation of pranlukast analogues against P. falciparum in a viability assay and a schizont rupture assay show the parasite activity was not consistent with the biochemical inhibition of Rh5, questioning the developability of pranlukast as an antimalarial. The high-throughput assay developed from this work has the capacity to screen large collections of small molecules to discover inhibitors of P. falciparum Rh5 for future development of invasion inhibitory antimalarials. A high-throughput screening assay was developed to identify inhibitors of Rh5. The assay was applied in a screen of the MMV Malaria Box and a known drug library. Pranlukast was identified as a hit, but could not be conclusively validated. Assay enables future screens of large compound libraries to discover Rh5 inhibitors.
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Affiliation(s)
- Brad E Sleebs
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria, 3052, Australia.
| | - Kate E Jarman
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria, 3052, Australia
| | - Sonja Frolich
- Research Centre for Infectious Diseases, School of Biological Sciences, University of Adelaide, Adelaide, South Australia, 5005, Australia
| | - Wilson Wong
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria, 3052, Australia
| | - Julie Healer
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria, 3052, Australia
| | - Weiwen Dai
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, 3052, Australia
| | - Isabelle S Lucet
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria, 3052, Australia
| | - Danny W Wilson
- Research Centre for Infectious Diseases, School of Biological Sciences, University of Adelaide, Adelaide, South Australia, 5005, Australia
| | - Alan F Cowman
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria, 3052, Australia
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18
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Fotoran WL, Kleiber N, Glitz C, Wunderlich G. A DNA Vaccine Encoding Plasmodium falciparum PfRH5 in Cationic Liposomes for Dermal Tattooing Immunization. Vaccines (Basel) 2020; 8:vaccines8040619. [PMID: 33092277 PMCID: PMC7711581 DOI: 10.3390/vaccines8040619] [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: 08/24/2020] [Revised: 10/12/2020] [Accepted: 10/14/2020] [Indexed: 11/16/2022] Open
Abstract
Vaccines are the primary means of controlling and preventing pandemics and outbreaks of pathogens such as bacteria, viruses, and parasites. However, a major drawback of naked DNA-based vaccines is their low immunogenicity and the amount of plasmid DNA necessary to elicit a response. Nano-sized liposomes can overcome this limitation, enhancing both nucleic acid stability and targeting to cells after administration. We tested two different DNA vaccines in cationic liposomes to improve the immunogenic properties. For this, we cloned the coding sequences of the Plasmodium falciparum reticulocyte binding protein homologue 5 (PfRH5) either alone or fused with small the small hepatitis virus (HBV) envelope antigen (HBsAg) encoding sequences, potentially resulting in HBsAg particles displaying PfRH5 on their outside. Instead of invasive intraperitoneal or intramuscular immunization, we employed intradermal immunization by tattooing nano-encapsulated DNA. Mice were immunized with 10 μg encapsulated DNA encoding PfRH5 alone or in fusion with HBsAg and this elicited antibodies against schizont extracts (titer of 104). Importantly, only IgG from animals immunized with PfRH5-HBs demonstrated sustained IgG-mediated inhibition in in vitro growth assays showing 58% and 39% blocking activity after 24 and 48 h, respectively. Intradermal tattoo-vaccination of encapsulated PfRH5-HBsAg coding plasmid DNA is effective and superior compared with an unfused PfRH5-DNA vaccine, suggesting that the HBsAg fusion may be advantageous with other vaccine antigens.
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Affiliation(s)
- Wesley Luzetti Fotoran
- Departamento de Parasitologia, Instituto de Ciências Biomédicas II, Universidade de São Paulo, São Paulo 05508-000, Brazil; (W.L.F.); (N.K.)
| | - Nicole Kleiber
- Departamento de Parasitologia, Instituto de Ciências Biomédicas II, Universidade de São Paulo, São Paulo 05508-000, Brazil; (W.L.F.); (N.K.)
| | - Christiane Glitz
- Department of Molecular Physiology, Institute of Animal Physiology, Westfälische Wilhelms University of Münster, 48149 Münster, Germany;
| | - Gerhard Wunderlich
- Departamento de Parasitologia, Instituto de Ciências Biomédicas II, Universidade de São Paulo, São Paulo 05508-000, Brazil; (W.L.F.); (N.K.)
- Correspondence: ; Tel.: +55-11-3091-7265
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19
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Burns AL, Sleebs BE, Siddiqui G, De Paoli AE, Anderson D, Liffner B, Harvey R, Beeson JG, Creek DJ, Goodman CD, McFadden GI, Wilson DW. Retargeting azithromycin analogues to have dual-modality antimalarial activity. BMC Biol 2020; 18:133. [PMID: 32993629 PMCID: PMC7526119 DOI: 10.1186/s12915-020-00859-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Accepted: 08/28/2020] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND Resistance to front-line antimalarials (artemisinin combination therapies) is spreading, and development of new drug treatment strategies to rapidly kill Plasmodium spp. malaria parasites is urgently needed. Azithromycin is a clinically used macrolide antibiotic proposed as a partner drug for combination therapy in malaria, which has also been tested as monotherapy. However, its slow-killing 'delayed-death' activity against the parasite's apicoplast organelle and suboptimal activity as monotherapy limit its application as a potential malaria treatment. Here, we explore a panel of azithromycin analogues and demonstrate that chemical modifications can be used to greatly improve the speed and potency of antimalarial action. RESULTS Investigation of 84 azithromycin analogues revealed nanomolar quick-killing potency directed against the very earliest stage of parasite development within red blood cells. Indeed, the best analogue exhibited 1600-fold higher potency than azithromycin with less than 48 hrs treatment in vitro. Analogues were effective against zoonotic Plasmodium knowlesi malaria parasites and against both multi-drug and artemisinin-resistant Plasmodium falciparum lines. Metabolomic profiles of azithromycin analogue-treated parasites suggested activity in the parasite food vacuole and mitochondria were disrupted. Moreover, unlike the food vacuole-targeting drug chloroquine, azithromycin and analogues were active across blood-stage development, including merozoite invasion, suggesting that these macrolides have a multi-factorial mechanism of quick-killing activity. The positioning of functional groups added to azithromycin and its quick-killing analogues altered their activity against bacterial-like ribosomes but had minimal change on 'quick-killing' activity. Apicoplast minus parasites remained susceptible to both azithromycin and its analogues, further demonstrating that quick-killing is independent of apicoplast-targeting, delayed-death activity. CONCLUSION We show that azithromycin and analogues can rapidly kill malaria parasite asexual blood stages via a fast action mechanism. Development of azithromycin and analogues as antimalarials offers the possibility of targeting parasites through both a quick-killing and delayed-death mechanism of action in a single, multifactorial chemotype.
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Affiliation(s)
- Amy L Burns
- Research Centre for Infectious Diseases, School of Biological Sciences, The University of Adelaide, Adelaide, 5005, Australia
| | - Brad E Sleebs
- Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, 3050, Australia
- Department of Medical Biology, University of Melbourne, Melbourne, Victoria, 3050, Australia
| | - Ghizal Siddiqui
- Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria, 3052, Australia
| | - Amanda E De Paoli
- Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria, 3052, Australia
| | - Dovile Anderson
- Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria, 3052, Australia
| | - Benjamin Liffner
- Research Centre for Infectious Diseases, School of Biological Sciences, The University of Adelaide, Adelaide, 5005, Australia
| | - Richard Harvey
- Research Centre for Infectious Diseases, School of Biological Sciences, The University of Adelaide, Adelaide, 5005, Australia
| | - James G Beeson
- Burnet Institute, Melbourne, Victoria, 3004, Australia
- Department of Medicine, University of Melbourne, Melbourne, Australia
- Central Clinical School and Department of Microbiology, Monash University, Melbourne, Australia
| | - Darren J Creek
- Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria, 3052, Australia
| | - Christopher D Goodman
- School of Biosciences, University of Melbourne, Melbourne, Victoria, 3010, Australia
| | - Geoffrey I McFadden
- School of Biosciences, University of Melbourne, Melbourne, Victoria, 3010, Australia
| | - Danny W Wilson
- Research Centre for Infectious Diseases, School of Biological Sciences, The University of Adelaide, Adelaide, 5005, Australia.
- Burnet Institute, Melbourne, Victoria, 3004, Australia.
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20
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Milheiro SA, Gonçalves J, Lopes RMRM, Madureira M, Lobo L, Lopes A, Nogueira F, Fontinha D, Prudêncio M, M Piedade MF, Pinto SN, Florindo PR, Moreira R. Half-Sandwich Cyclopentadienylruthenium(II) Complexes: A New Antimalarial Chemotype. Inorg Chem 2020; 59:12722-12732. [PMID: 32838513 DOI: 10.1021/acs.inorgchem.0c01795] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
A small library of "half-sandwich" cyclopentadienylruthenium(II) compounds of the general formula [(η5-C5R5)Ru(PPh3)(N-N)][PF6], a scaffold hitherto absent from the toolbox of antiplasmodials, was screened for activity against the blood stage of CQ-sensitive 3D7-GFP, CQ-resistant Dd2, and artemisinin-resistant IPC5202 Plasmodium falciparum strains and the liver stage of Plasmodium berghei. The best-performing compounds displayed dual-stage activity, with single-digit nanomolar IC50 values against blood-stage malaria parasites, nanomolar activity against liver-stage parasites, and residual cytotoxicity against HepG2 and Huh7 mammalian cells. The parasitic absorption/distribution of 7-nitrobenzoxadiazole-appended fluorescent compounds Ru4 and Ru5 was investigated by confocal fluorescence microscopy, revealing parasite-selective absorption in infected erythrocytes and nuclear accumulation of both compounds. The lead compound Ru2 impaired asexual parasite differentiation, exhibiting fast parasiticidal activity against both ring and trophozoite stages of a synchronized culture of the P. falciparum 3D7 strain. These results point to cyclopentadienylruthenium(II) complexes as a highly promising chemotype for the development of dual-stage antiplasmodials.
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Affiliation(s)
- Sofia A Milheiro
- Instituto de Investigação do Medicamento (iMed.ULisboa), Faculdade de Farmácia, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal
| | - Joana Gonçalves
- Instituto de Investigação do Medicamento (iMed.ULisboa), Faculdade de Farmácia, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal
| | - Ricardo M R M Lopes
- Instituto de Investigação do Medicamento (iMed.ULisboa), Faculdade de Farmácia, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal
| | - Margarida Madureira
- Instituto de Investigação do Medicamento (iMed.ULisboa), Faculdade de Farmácia, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal
| | - Lis Lobo
- Department of Medical Parasitology, Global Health and Tropical Medicine, GHTM, Instituto de Higiene e Medicina Tropical, IHMT, Universidade Nova de Lisboa, UNL, Rua da Junqueira, 100, 1349-008 Lisboa, Portugal
| | - Andreia Lopes
- Department of Medical Parasitology, Global Health and Tropical Medicine, GHTM, Instituto de Higiene e Medicina Tropical, IHMT, Universidade Nova de Lisboa, UNL, Rua da Junqueira, 100, 1349-008 Lisboa, Portugal
| | - Fátima Nogueira
- Department of Medical Parasitology, Global Health and Tropical Medicine, GHTM, Instituto de Higiene e Medicina Tropical, IHMT, Universidade Nova de Lisboa, UNL, Rua da Junqueira, 100, 1349-008 Lisboa, Portugal
| | - Diana Fontinha
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal
| | - Miguel Prudêncio
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal
| | - M Fátima M Piedade
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal.,Departamento de Química e Bioquímica, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal
| | - Sandra N Pinto
- iBB-Institute for Bioengineering and Biosciences, Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal
| | - Pedro R Florindo
- Instituto de Investigação do Medicamento (iMed.ULisboa), Faculdade de Farmácia, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal
| | - Rui Moreira
- Instituto de Investigação do Medicamento (iMed.ULisboa), Faculdade de Farmácia, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal
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21
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Opuni KFM, Koy C, Russ M, Reepmeyer M, Danquah BD, Weresow M, Alef A, Lorenz P, Thiesen HJ, Glocker MO. ITEM-THREE analysis of a monoclonal anti-malaria antibody reveals its assembled epitope on the pfMSP1 19 antigen. J Biol Chem 2020; 295:14987-14997. [PMID: 32848020 DOI: 10.1074/jbc.ra120.014802] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 08/18/2020] [Indexed: 11/06/2022] Open
Abstract
Rapid diagnostic tests are first-line assays for diagnosing infectious diseases, such as malaria. To minimize false positive and false negative test results in population-screening assays, high-quality reagents and well-characterized antigens and antibodies are needed. An important property of antigen-antibody binding is recognition specificity, which best can be estimated by mapping an antibody's epitope on the respective antigen. We have cloned a malarial antigen-containing fusion protein, MBP-pfMSP119, in Escherichia coli, which then was structurally and functionally characterized before and after high pressure-assisted enzymatic digestion. We then used our previously developed method, intact transition epitope mapping-targeted high-energy rupture of extracted epitopes (ITEM-THREE), to map the area on the MBP-pfMSP119 antigen surface that is recognized by the anti-pfMSP119 antibody G17.12. We identified three epitope-carrying peptides, 386GRNISQHQCVKKQCPQNSGCFRHLDE411, 386GRNISQHQCVKKQCPQNSGCFRHLDEREE414, and 415CKCLLNYKQE424, from the GluC-derived peptide mixture. These peptides belong to an assembled (conformational) epitope on the MBP-pfMSP119 antigen whose identification was substantiated by positive and negative control experiments. In conclusion, our data help to establish a workflow to obtain high-quality control data for diagnostic assays, including the use of ITEM-THREE as a powerful analytical tool. Data are available via ProteomeXchange: PXD019717.
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Affiliation(s)
- Kwabena F M Opuni
- Proteome Center Rostock, University Medicine Rostock and University of Rostock, Rostock, Germany; Department of Pharmaceutical Chemistry, School of Pharmacy, College of Health, University of Ghana, Legon, Ghana
| | - Cornelia Koy
- Proteome Center Rostock, University Medicine Rostock and University of Rostock, Rostock, Germany
| | - Manuela Russ
- Proteome Center Rostock, University Medicine Rostock and University of Rostock, Rostock, Germany
| | - Maren Reepmeyer
- Proteome Center Rostock, University Medicine Rostock and University of Rostock, Rostock, Germany
| | - Bright D Danquah
- Proteome Center Rostock, University Medicine Rostock and University of Rostock, Rostock, Germany
| | | | | | - Peter Lorenz
- Institute for Immunology, University Medicine Rostock, Rostock, Germany
| | | | - Michael O Glocker
- Proteome Center Rostock, University Medicine Rostock and University of Rostock, Rostock, Germany.
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22
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PfCERLI1 is a conserved rhoptry associated protein essential for Plasmodium falciparum merozoite invasion of erythrocytes. Nat Commun 2020; 11:1411. [PMID: 32179747 PMCID: PMC7075938 DOI: 10.1038/s41467-020-15127-w] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 02/15/2020] [Indexed: 12/01/2022] Open
Abstract
The disease-causing blood-stage of the Plasmodium falciparum lifecycle begins with invasion of human erythrocytes by merozoites. Many vaccine candidates with key roles in binding to the erythrocyte surface and entry are secreted from the large bulb-like rhoptry organelles at the apical tip of the merozoite. Here we identify an essential role for the conserved protein P. falciparum Cytosolically Exposed Rhoptry Leaflet Interacting protein 1 (PfCERLI1) in rhoptry function. We show that PfCERLI1 localises to the cytosolic face of the rhoptry bulb membrane and knockdown of PfCERLI1 inhibits merozoite invasion. While schizogony and merozoite organelle biogenesis appear normal, biochemical techniques and semi-quantitative super-resolution microscopy show that PfCERLI1 knockdown prevents secretion of key rhoptry antigens that coordinate merozoite invasion. PfCERLI1 is a rhoptry associated protein identified to have a direct role in function of this essential merozoite invasion organelle, which has broader implications for understanding apicomplexan invasion biology. Rhoptries are essential organelles for invasion of erythrocytes by Plasmodium. Here, the authors characterize the rhoptry-associated protein CERLI1 using quantitative super-resolution microscopy, showing that it is important for parasite invasion and secretion of rhoptry proteins including vaccine antigens.
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23
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Warszawski S, Dekel E, Campeotto I, Marshall JM, Wright KE, Lyth O, Knop O, Regev-Rudzki N, Higgins MK, Draper SJ, Baum J, Fleishman SJ. Design of a basigin-mimicking inhibitor targeting the malaria invasion protein RH5. Proteins 2020; 88:187-195. [PMID: 31325330 PMCID: PMC6904230 DOI: 10.1002/prot.25786] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 07/02/2019] [Accepted: 07/12/2019] [Indexed: 11/07/2022]
Abstract
Many human pathogens use host cell-surface receptors to attach and invade cells. Often, the host-pathogen interaction affinity is low, presenting opportunities to block invasion using a soluble, high-affinity mimic of the host protein. The Plasmodium falciparum reticulocyte-binding protein homolog 5 (RH5) provides an exciting candidate for mimicry: it is highly conserved and its moderate affinity binding to the human receptor basigin (KD ≥1 μM) is an essential step in erythrocyte invasion by this malaria parasite. We used deep mutational scanning of a soluble fragment of human basigin to systematically characterize point mutations that enhance basigin affinity for RH5 and then used Rosetta to design a variant within the sequence space of affinity-enhancing mutations. The resulting seven-mutation design exhibited 1900-fold higher affinity (KD approximately 1 nM) for RH5 with a very slow binding off rate (0.23 h-1 ) and reduced the effective Plasmodium growth-inhibitory concentration by at least 10-fold compared to human basigin. The design provides a favorable starting point for engineering on-rate improvements that are likely to be essential to reach therapeutically effective growth inhibition.
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Affiliation(s)
- Shira Warszawski
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Elya Dekel
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Ivan Campeotto
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Jennifer M. Marshall
- Jenner Institute, University of Oxford, Old Road Campus Research Building, Oxford, OX3 7DQ, UK
| | - Katherine E. Wright
- Department of Life Sciences, Imperial College London, Sir Alexander Fleming Building, Exhibition Road, South Kensington, London, UK
| | - Oliver Lyth
- Department of Life Sciences, Imperial College London, Sir Alexander Fleming Building, Exhibition Road, South Kensington, London, UK
| | - Orli Knop
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Neta Regev-Rudzki
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Matthew K Higgins
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Simon J Draper
- Jenner Institute, University of Oxford, Old Road Campus Research Building, Oxford, OX3 7DQ, UK
| | - Jake Baum
- Department of Life Sciences, Imperial College London, Sir Alexander Fleming Building, Exhibition Road, South Kensington, London, UK
| | - Sarel J Fleishman
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel
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24
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The effects of dyslipidaemia and cholesterol modulation on erythrocyte susceptibility to malaria parasite infection. Malar J 2019; 18:381. [PMID: 31783858 PMCID: PMC6884832 DOI: 10.1186/s12936-019-3016-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2019] [Accepted: 11/20/2019] [Indexed: 11/12/2022] Open
Abstract
Background Malaria disease commences when blood-stage parasites, called merozoites, invade human erythrocytes. Whilst the process of invasion is traditionally seen as being entirely merozoite-driven, emerging data suggests erythrocyte biophysical properties markedly influence invasion. Cholesterol is a major determinant of cell membrane biophysical properties demanding its interrogation as a potential mediator of resistance to merozoite invasion of the erythrocyte. Methods Biophysical measurements of erythrocyte deformability by flicker spectroscopy were used to assess changes in erythrocyte bending modulus on forced integration of cholesterol and how these artificial changes affect invasion by human Plasmodium falciparum merozoites. To validate these observations in a natural context, either murine Plasmodium berghei or human Plasmodium falciparum merozoites were tested for their ability to invade erythrocytes from a hypercholesterolaemic mouse model or human clinical erythrocyte samples deriving from patients with a range of serum cholesterol concentrations, respectively. Results Erythrocyte bending modulus (a measure of deformability) was shown to be markedly affected by artificial modulation of cholesterol content and negatively correlated with merozoite invasion efficiency. In an in vitro infection context, however, erythrocytes taken from hypercholesterolaemic mice or from human clinical samples with varying serum cholesterol levels showed little difference in their susceptibility to merozoite invasion. Explaining this, membrane cholesterol levels in both mouse and human hypercholesterolaemia erythrocytes were subsequently found to be no different from matched normal serum controls. Conclusions Based on these observations, serum cholesterol does not appear to impact on erythrocyte susceptibility to merozoite entry. Indeed, no relationship between serum cholesterol and cholesterol content of the erythrocyte is apparent. This work, nonetheless, suggests that native polymorphisms which do affect membrane lipid composition would be expected to affect parasite entry. This supports investigation of erythrocyte biophysical properties in endemic settings, which may yet identify naturally protective lipid-related polymorphisms.
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25
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Boyle MJ, Chan JA, Handayuni I, Reiling L, Feng G, Hilton A, Kurtovic L, Oyong D, Piera KA, Barber BE, William T, Eisen DP, Minigo G, Langer C, Drew DR, de Labastida Rivera F, Amante FH, Williams TN, Kinyanjui S, Marsh K, Doolan DL, Engwerda C, Fowkes FJI, Grigg MJ, Mueller I, McCarthy JS, Anstey NM, Beeson JG. IgM in human immunity to Plasmodium falciparum malaria. SCIENCE ADVANCES 2019; 5:eaax4489. [PMID: 31579826 PMCID: PMC6760923 DOI: 10.1126/sciadv.aax4489] [Citation(s) in RCA: 70] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Accepted: 09/03/2019] [Indexed: 05/15/2023]
Abstract
Most studies on human immunity to malaria have focused on the roles of immunoglobulin G (IgG), whereas the roles of IgM remain undefined. Analyzing multiple human cohorts to assess the dynamics of malaria-specific IgM during experimentally induced and naturally acquired malaria, we identified IgM activity against blood-stage parasites. We found that merozoite-specific IgM appears rapidly in Plasmodium falciparum infection and is prominent during malaria in children and adults with lifetime exposure, together with IgG. Unexpectedly, IgM persisted for extended periods of time; we found no difference in decay of merozoite-specific IgM over time compared to that of IgG. IgM blocked merozoite invasion of red blood cells in a complement-dependent manner. IgM was also associated with significantly reduced risk of clinical malaria in a longitudinal cohort of children. These findings suggest that merozoite-specific IgM is an important functional and long-lived antibody response targeting blood-stage malaria parasites that contributes to malaria immunity.
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Affiliation(s)
- M. J. Boyle
- Burnet Institute for Medical Research and Public Health, Melbourne, Victoria, Australia
- Global and Tropical Health Division, Menzies School of Health Research, Darwin, Northern Territory, Australia
- QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
- Corresponding author. (M.J.B.); (J.G.B.)
| | - J. A. Chan
- Burnet Institute for Medical Research and Public Health, Melbourne, Victoria, Australia
| | - I. Handayuni
- Global and Tropical Health Division, Menzies School of Health Research, Darwin, Northern Territory, Australia
| | - L. Reiling
- Burnet Institute for Medical Research and Public Health, Melbourne, Victoria, Australia
| | - G. Feng
- Burnet Institute for Medical Research and Public Health, Melbourne, Victoria, Australia
- Department of Medicine, University of Melbourne, Melbourne, Victoria, Australia
| | - A. Hilton
- Burnet Institute for Medical Research and Public Health, Melbourne, Victoria, Australia
| | - L. Kurtovic
- Burnet Institute for Medical Research and Public Health, Melbourne, Victoria, Australia
- Department of Immunology and Pathology, Monash University, Melbourne, Victoria, Australia
| | - D. Oyong
- Global and Tropical Health Division, Menzies School of Health Research, Darwin, Northern Territory, Australia
- Charles Darwin University, Darwin, Northern Territory, Australia
| | - K. A. Piera
- Global and Tropical Health Division, Menzies School of Health Research, Darwin, Northern Territory, Australia
| | - B. E. Barber
- Global and Tropical Health Division, Menzies School of Health Research, Darwin, Northern Territory, Australia
- QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
- Infectious Diseases Society Sabah-Menzies School of Health Research Clinical Research Unit, Queen Elizabeth Hospital, Kota Kinabalu, Sabah, Malaysia
| | - T. William
- Infectious Diseases Society Sabah-Menzies School of Health Research Clinical Research Unit, Queen Elizabeth Hospital, Kota Kinabalu, Sabah, Malaysia
- Gleneagles Hospital Kota Kinabalu Sabah, Malaysia
| | - D. P. Eisen
- Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, Queensland, Australia
| | - G. Minigo
- Global and Tropical Health Division, Menzies School of Health Research, Darwin, Northern Territory, Australia
- Charles Darwin University, Darwin, Northern Territory, Australia
| | - C. Langer
- Burnet Institute for Medical Research and Public Health, Melbourne, Victoria, Australia
| | - D. R. Drew
- Burnet Institute for Medical Research and Public Health, Melbourne, Victoria, Australia
| | | | - F. H. Amante
- QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
| | - T. N. Williams
- Kenya Medical Research Institute (KEMRI), Centre for Geographic Medicine, Coast, KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
- Imperial College, London, UK
| | - S. Kinyanjui
- Kenya Medical Research Institute (KEMRI), Centre for Geographic Medicine, Coast, KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
- Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - K. Marsh
- Kenya Medical Research Institute (KEMRI), Centre for Geographic Medicine, Coast, KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
- Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - D. L. Doolan
- Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, Queensland, Australia
| | - C. Engwerda
- QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
| | - F. J. I. Fowkes
- Burnet Institute for Medical Research and Public Health, Melbourne, Victoria, Australia
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, Victoria, Australia
- Department of Epidemiology and Preventive Medicine, Department of Infectious Diseases, Monash University, Melbourne, Victoria, Australia
| | - M. J. Grigg
- Global and Tropical Health Division, Menzies School of Health Research, Darwin, Northern Territory, Australia
- Infectious Diseases Society Sabah-Menzies School of Health Research Clinical Research Unit, Queen Elizabeth Hospital, Kota Kinabalu, Sabah, Malaysia
| | - I. Mueller
- Walter and Eliza Hall Institute, Melbourne, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Melbourne, Victoria, Australia
- Department of Parasites and Insect Vectors, Institute Pasteur, Paris, France
| | - J. S. McCarthy
- QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
- The University of Queensland, Brisbane, Queensland, Australia
| | - N. M. Anstey
- Global and Tropical Health Division, Menzies School of Health Research, Darwin, Northern Territory, Australia
- Charles Darwin University, Darwin, Northern Territory, Australia
| | - J. G. Beeson
- Burnet Institute for Medical Research and Public Health, Melbourne, Victoria, Australia
- Department of Medicine, University of Melbourne, Melbourne, Victoria, Australia
- Department of Microbiology and Central Clinical School, Monash University, Melbourne, Victoria, Australia
- Corresponding author. (M.J.B.); (J.G.B.)
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26
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Satchwell TJ, Wright KE, Haydn-Smith KL, Sánchez-Román Terán F, Moura PL, Hawksworth J, Frayne J, Toye AM, Baum J. Genetic manipulation of cell line derived reticulocytes enables dissection of host malaria invasion requirements. Nat Commun 2019; 10:3806. [PMID: 31444345 PMCID: PMC6707200 DOI: 10.1038/s41467-019-11790-w] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Accepted: 08/05/2019] [Indexed: 12/12/2022] Open
Abstract
Investigating the role that host erythrocyte proteins play in malaria infection is hampered by the genetic intractability of this anucleate cell. Here we report that reticulocytes derived through in vitro differentiation of an enucleation-competent immortalized erythroblast cell line (BEL-A) support both successful invasion and intracellular development of the malaria parasite Plasmodium falciparum. Using CRISPR-mediated gene knockout and subsequent complementation, we validate an essential role for the erythrocyte receptor basigin in P. falciparum invasion and demonstrate rescue of invasive susceptibility by receptor re-expression. Successful invasion of reticulocytes complemented with a truncated mutant excludes a functional role for the basigin cytoplasmic domain during invasion. Contrastingly, knockout of cyclophilin B, reported to participate in invasion and interact with basigin, did not impact invasive susceptibility of reticulocytes. These data establish the use of reticulocytes derived from immortalized erythroblasts as a powerful model system to explore hypotheses regarding host receptor requirements for P. falciparum invasion.
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Affiliation(s)
- Timothy J Satchwell
- School of Biochemistry, University of Bristol, Bristol, UK.
- NIHR Blood and Transplant Research Unit, University of Bristol, Bristol, UK.
- Bristol Institute for Transfusion Sciences, National Health Service Blood and Transplant (NHSBT), Bristol, UK.
| | - Katherine E Wright
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, United Kingdom.
| | - Katy L Haydn-Smith
- School of Biochemistry, University of Bristol, Bristol, UK
- NIHR Blood and Transplant Research Unit, University of Bristol, Bristol, UK
- Bristol Institute for Transfusion Sciences, National Health Service Blood and Transplant (NHSBT), Bristol, UK
| | | | - Pedro L Moura
- School of Biochemistry, University of Bristol, Bristol, UK
| | | | - Jan Frayne
- School of Biochemistry, University of Bristol, Bristol, UK
- NIHR Blood and Transplant Research Unit, University of Bristol, Bristol, UK
| | - Ashley M Toye
- School of Biochemistry, University of Bristol, Bristol, UK
- NIHR Blood and Transplant Research Unit, University of Bristol, Bristol, UK
- Bristol Institute for Transfusion Sciences, National Health Service Blood and Transplant (NHSBT), Bristol, UK
| | - Jake Baum
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, United Kingdom.
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27
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Marin-Mogollon C, Salman AM, Koolen KMJ, Bolscher JM, van Pul FJA, Miyazaki S, Imai T, Othman AS, Ramesar J, van Gemert GJ, Kroeze H, Chevalley-Maurel S, Franke-Fayard B, Sauerwein RW, Hill AVS, Dechering KJ, Janse CJ, Khan SM. A P. falciparum NF54 Reporter Line Expressing mCherry-Luciferase in Gametocytes, Sporozoites, and Liver-Stages. Front Cell Infect Microbiol 2019; 9:96. [PMID: 31058097 PMCID: PMC6477837 DOI: 10.3389/fcimb.2019.00096] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Accepted: 03/22/2019] [Indexed: 12/16/2022] Open
Abstract
Transgenic malaria parasites expressing fluorescent and bioluminescent proteins are valuable tools to interrogate malaria-parasite biology and to evaluate drugs and vaccines. Using CRISPR/Cas9 methodology a transgenic Plasmodium falciparum (Pf) NF54 line was generated that expresses a fusion of mCherry and luciferase genes under the control of the Pf etramp10.3 gene promoter (line mCherry-luc@etramp10.3). Pf etramp10.3 is related to rodent Plasmodium uis4 and the uis4 promoter has been used to drive high transgene expression in rodent parasite sporozoites and liver-stages. We examined transgene expression throughout the complete life cycle and compared this expression to transgenic lines expressing mCherry-luciferase and GFP-luciferase under control of the constitutive gapdh and eef1a promoters. The mCherry-luc@etramp10.3 parasites express mCherry in gametocytes, sporozoites, and liver-stages. While no mCherry signal was detected in asexual blood-stage parasites above background levels, luciferase expression was detected in asexual blood-stages, as well as in gametocytes, sporozoites and liver-stages, with the highest levels of reporter expression detected in stage III-V gametocytes and in sporozoites. The expression of mCherry and luciferase in gametocytes and sporozoites makes this transgenic parasite line suitable to use in in vitro assays that examine the effect of transmission blocking inhibitors and to analyse gametocyte and sporozoite biology.
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Affiliation(s)
| | - Ahmed M Salman
- Nuffield Department of Medicine, The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | | | | | - Fiona J A van Pul
- Department of Parasitology, Leiden University Medical Center, Leiden, Netherlands
| | - Shinya Miyazaki
- Department of Parasitology, Leiden University Medical Center, Leiden, Netherlands
| | - Takashi Imai
- Department of Parasitology, Leiden University Medical Center, Leiden, Netherlands.,Department of Infectious Diseases and Host Defense, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - Ahmad Syibli Othman
- Department of Parasitology, Leiden University Medical Center, Leiden, Netherlands.,Faculty of Health Sciences, Universiti Sultan Zainal Abidin, Terengganu, Malaysia
| | - Jai Ramesar
- Department of Parasitology, Leiden University Medical Center, Leiden, Netherlands
| | - Geert-Jan van Gemert
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, Netherlands
| | - Hans Kroeze
- Department of Parasitology, Leiden University Medical Center, Leiden, Netherlands
| | | | | | - Robert W Sauerwein
- TropIQ Health Sciences, Nijmegen, Netherlands.,Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, Netherlands
| | - Adrian V S Hill
- Nuffield Department of Medicine, The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | | | - Chris J Janse
- Department of Parasitology, Leiden University Medical Center, Leiden, Netherlands
| | - Shahid M Khan
- Department of Parasitology, Leiden University Medical Center, Leiden, Netherlands
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Drew DR, Sanders PR, Weiss G, Gilson PR, Crabb BS, Beeson JG. Functional Conservation of the AMA1 Host-Cell Invasion Ligand Between P. falciparum and P. vivax: A Novel Platform to Accelerate Vaccine and Drug Development. J Infect Dis 2019; 217:498-507. [PMID: 29165651 DOI: 10.1093/infdis/jix583] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Accepted: 11/17/2017] [Indexed: 01/20/2023] Open
Abstract
Plasmodium vivax and P. falciparum malaria species have diverged significantly in receptor-ligand interactions and host-cell invasion. One protein common to both is the merozoite invasion ligand AMA1. While the general structure of AMA1 is similar between species, their sequences are divergent. Surprisingly, it was possible to genetically replace PfAMA1 with PvAMA1 in P. falciparum parasites. PvAMA1 complemented PfAMA1 function and supported invasion of erythrocytes by P. falciparum. Genetically modified P. falciparum expressing PvAMA1 evaded the invasion inhibitory effects of antibodies to PfAMA1, demonstrating species specificity of functional antibodies. We generated antibodies to recombinant PvAMA1 that effectively inhibited invasion, confirming the function of PvAMA1 in genetically modified parasites. Results indicate significant molecular flexibility in AMA1 enabling conserved function despite substantial sequence divergence across species. This provides powerful new tools to quantify the inhibitory activities of antibodies or drugs targeting PvAMA1, opening new opportunities for vaccine and therapeutic development against P. vivax.
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Affiliation(s)
| | | | | | | | - Brendan S Crabb
- Burnet Institute, Melbourne, Australia.,Department of Medicine, University of Melbourne, Victoria, Australia.,Department of Microbiology and Immunology, University of Melbourne, Victoria, Australia
| | - James G Beeson
- Burnet Institute, Melbourne, Australia.,Department of Medicine, University of Melbourne, Victoria, Australia.,Department of Microbiology and Immunology, University of Melbourne, Victoria, Australia.,Central Clinical School and Department of Microbiology, Monash University, Victoria, Australia
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29
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Targets of complement-fixing antibodies in protective immunity against malaria in children. Nat Commun 2019; 10:610. [PMID: 30723225 PMCID: PMC6363798 DOI: 10.1038/s41467-019-08528-z] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 01/07/2019] [Indexed: 12/31/2022] Open
Abstract
Antibodies against P. falciparum merozoites fix complement to inhibit blood-stage replication in naturally-acquired and vaccine-induced immunity; however, specific targets of these functional antibodies and their importance in protective immunity are unknown. Among malaria-exposed individuals, we show that complement-fixing antibodies to merozoites are more strongly correlated with protective immunity than antibodies that inhibit growth quantified using the current reference assay for merozoite vaccine evaluation. We identify merozoite targets of complement-fixing antibodies and identify antigen-specific complement-fixing antibodies that are strongly associated with protection from malaria in a longitudinal study of children. Using statistical modelling, combining three different antigens targeted by complement-fixing antibodies could increase the potential protective effect to over 95%, and we identify antigens that were common in the most protective combinations. Our findings support antibody-complement interactions against merozoite antigens as important anti-malaria immune mechanisms, and identify specific merozoite antigens for further evaluation as vaccine candidates. Antibodies against Plasmodium falciparum merozoites that fix complement can inhibit blood-stage replication. Here, Reiling et al. show that complement-fixing antibodies strongly correlate with protective immunity in children, identify the merozoite targets, and predict antigen combinations that should result in strong protection.
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30
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Tripeptide analogues of MG132 as protease inhibitors. Bioorg Med Chem 2018; 27:436-441. [PMID: 30581047 DOI: 10.1016/j.bmc.2018.12.022] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 12/12/2018] [Accepted: 12/13/2018] [Indexed: 12/17/2022]
Abstract
The 26S proteasome and calpain are linked to a number of important human diseases. Here, we report a series of analogues of the prototypical tripeptide aldehyde inhibitor MG132 that show a unique combination of high activity and selectivity for calpains over proteasome. Tripeptide aldehydes (1-3) with an aromatic P3 substituent show enhanced activity and selectivity against ovine calpain 2 relative to chymotrypsin-like activity of proteasome. Docking studies reveal the key contacts between inhibitors and calpain to confirm the importance of the S3 pocket with respect to selectivity between calpains 1 and 2 and the proteasome.
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31
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Oyong DA, Kenangalem E, Poespoprodjo JR, Beeson JG, Anstey NM, Price RN, Boyle MJ. Loss of complement regulatory proteins on uninfected erythrocytes in vivax and falciparum malaria anemia. JCI Insight 2018; 3:124854. [PMID: 30429373 PMCID: PMC6303009 DOI: 10.1172/jci.insight.124854] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Accepted: 10/16/2018] [Indexed: 01/12/2023] Open
Abstract
Anemia is a major complication of malaria, driven largely by loss of uninfected RBCs during infection. RBC clearance through loss of complement regulatory proteins (CRPs) is a significant contributor to anemia in Plasmodium falciparum infection, but its role in Plasmodium vivax infection is unknown. CRP loss increases RBC susceptibility to macrophage clearance, a process that is also regulated by CD47. We compared CRPs and CD47 expression on infected and uninfected RBCs in adult patients with vivax and falciparum malaria and different anemia severities from Papua, Indonesia. Complement activation and parasite-specific complement-fixing antibodies were measured by ELISA. Levels of CR1 and CD55 were reduced in severe anemia in both falciparum and vivax malaria. Loss of CRPs and CD47 was restricted to uninfected RBCs, with infected RBCs having higher expression. There was no association among complement-fixing antibodies, complement activation, and CRP loss. Our findings demonstrate that CRP loss is a pan-species, age-independent mechanism of malarial anemia. Higher levels of CRP and CD47 expression on infected RBCs suggest that parasites are protected from complement-mediated destruction and macrophage clearance. Lack of associations between protective antibodies and CRP loss highlight that complement pathogenic and protective pathways are distinct mechanisms during infection.
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Affiliation(s)
- Damian A. Oyong
- Menzies School of Health Research and,Charles Darwin University, Darwin, North Territory, Australia
| | - Enny Kenangalem
- Mimika District Health Authority and,Papuan Health and Community Development Foundation, Timika, Papua, Indonesia
| | - Jeanne R. Poespoprodjo
- Mimika District Health Authority and,Papuan Health and Community Development Foundation, Timika, Papua, Indonesia.,Department of Paediatrics, Faculty of Medicine, Gadjah Mada University, Yogyakarta, Central Java, Indonesia
| | - James G. Beeson
- Burnet Institute, Melbourne, Victoria, Australia.,Department of Medicine, University of Melbourne, Melbourne, Victoria, Australia.,Department of Microbiology and Central Clinical School, Monash University, Melbourne, Victoria, Australia
| | | | - Ric N. Price
- Menzies School of Health Research and,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom
| | - Michelle J. Boyle
- Menzies School of Health Research and,Burnet Institute, Melbourne, Victoria, Australia
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32
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33
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Sarkar P, Chattopadhyay A. GFP fluorescence: A few lesser-known nuggets that make it work. J Biosci 2018; 43:421-430. [PMID: 30002261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Use of Green Fluorescent Protein (GFP) as a marker has revolutionized biological research in the last few decades. In this brief commentary, we reflect upon the success story of GFP and highlight a few lesser-known facets about GFP that add up to its usefulness.
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Affiliation(s)
- Parijat Sarkar
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500 007, India,
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34
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Chisholm SA, Kalanon M, Nebl T, Sanders PR, Matthews KM, Dickerman BK, Gilson PR, de Koning-Ward TF. The malaria PTEX component PTEX88 interacts most closely with HSP101 at the host-parasite interface. FEBS J 2018; 285:2037-2055. [PMID: 29637707 DOI: 10.1111/febs.14463] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Revised: 03/08/2018] [Accepted: 04/03/2018] [Indexed: 12/28/2022]
Abstract
The pathogenic nature of malaria infections is due in part to the export of hundreds of effector proteins that actively remodel the host erythrocyte. The Plasmodium translocon of exported proteins (PTEX) has been shown to facilitate the trafficking of proteins into the host cell, a process that is essential for the survival of the parasite. The role of the auxiliary PTEX component PTEX88 remains unclear, as previous attempts to elucidate its function through reverse genetic approaches showed that in contrast to the core components PTEX150 and HSP101, knockdown of PTEX88 did not give rise to an export phenotype. Here, we have used biochemical approaches to understand how PTEX88 assembles within the translocation machinery. Proteomic analysis of the PTEX88 interactome showed that PTEX88 interacts closely with HSP101 but has a weaker affinity with the other core constituents of PTEX. PTEX88 was also found to associate with other PV-resident proteins, including chaperones and members of the exported protein-interacting complex that interacts with the major virulence factor PfEMP1, the latter contributing to cytoadherence and parasite virulence. Despite being expressed for the duration of the blood-stage life cycle, PTEX88 was only discretely observed at the parasitophorous vacuole membrane during ring stages and could not always be detected in the major high molecular weight complex that contains the other core components of PTEX, suggesting that its interaction with the PTEX complex may be dynamic. Together, these data have enabled the generation of an updated model of PTEX that now includes how PTEX88 assembles within the complex.
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Affiliation(s)
| | - Ming Kalanon
- School of Medicine, Deakin University, Waurn Ponds, Australia
| | - Thomas Nebl
- The Walter and Eliza Hall Institute, Parkville, Australia
| | - Paul R Sanders
- Burnet Institute, Prahran, Australia.,Monash University, Melbourne, Australia
| | | | | | - Paul R Gilson
- Burnet Institute, Prahran, Australia.,Monash University, Melbourne, Australia
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35
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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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36
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Nguyen N, Wilson DW, Nagalingam G, Triccas JA, Schneider EK, Li J, Velkov T, Baell J. Broad activity of diphenyleneiodonium analogues against Mycobacterium tuberculosis, malaria parasites and bacterial pathogens. Eur J Med Chem 2017; 148:507-518. [PMID: 29269132 DOI: 10.1016/j.ejmech.2017.10.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Revised: 09/07/2017] [Accepted: 10/04/2017] [Indexed: 01/06/2023]
Abstract
In this study, a structure-activity relationship (SAR) compound series based on the NDH-2 inhibitor diphenyleneiodonium (DPI) was synthesised. Compounds were evaluated primarily for in vitro efficacy against Gram-positive and Gram-negative bacteria, commonly responsible for nosocomial and community acquired infections. In addition, we also assessed the activity of these compounds against Mycobacterium tuberculosis (Tuberculosis) and Plasmodium spp. (Malaria). This led to the discovery of highly potent compounds active against bacterial pathogens and malaria parasites in the low nanomolar range, several of which were significantly less toxic to mammalian cells.
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Affiliation(s)
- Nghi Nguyen
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences Monash University, VIC, 3052, Australia
| | - Danny W Wilson
- Research Centre for Infectious Diseases, School of Biological Sciences, University of Adelaide, Adelaide 5005, Australia; Macfarlane Burnet Institute for Medical Research and Public Health, Melbourne, Victoria 3004, Australia
| | - Gayathri Nagalingam
- Microbial Pathogenesis and Immunity Group, Discipline of Infectious Diseases and Immunology, Sydney Medical School, University of Sydney, Sydney, NSW, Australia
| | - James A Triccas
- Microbial Pathogenesis and Immunity Group, Discipline of Infectious Diseases and Immunology, Sydney Medical School, University of Sydney, Sydney, NSW, Australia
| | - Elena K Schneider
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences Monash University, VIC, 3052, Australia
| | - Jian Li
- Monash Biomedicine Discovery Institute, Department of Microbiology, Monash University, VIC, 3800, Australia
| | - Tony Velkov
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences Monash University, VIC, 3052, Australia.
| | - Jonathan Baell
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences Monash University, VIC, 3052, Australia; School of Pharmaceutical Sciences, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing 211816, People's Republic of China.
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37
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Fotoran WL, Santangelo R, de Miranda BNM, Irvine DJ, Wunderlich G. DNA-Loaded Cationic Liposomes Efficiently Function as a Vaccine against Malarial Proteins. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2017; 7:1-10. [PMID: 28879213 PMCID: PMC5581859 DOI: 10.1016/j.omtm.2017.08.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Accepted: 08/18/2017] [Indexed: 12/14/2022]
Abstract
The delivery of antigens as DNA vaccines is an efficient alternative to induce immune responses against antigens, which are difficult to produce in recombinant form. However, the delivery of naked DNA is ineffective or relies on sophisticated ballistic devices. Here, we show a combination of liposome application and naked DNA vaccine that successfully overcomes these problems. Upon entrapment of plasmids encoding different antigens in cationic particles, transfection efficiencies similar to commercial kits were achieved in in vitro cell cultures. The liposome-based approach provided strong humoral responses against three malarial antigens, namely the Circumsporozoite protein and the C terminus of merozoite surface protein 1 from Plasmodium vivax (titers 104 or 103–104, respectively) and P. falciparum Rhoptry antigen 5 from Plasmodium falciparum (titers 103–104). When employed in P. falciparum growth-inhibition assays, antibodies demonstrated consistent reinvasion-blocking activities that were dose dependent. Liposome-formulated DNA vaccines may prove useful when targets cannot be produced as recombinant proteins and when conformation-dependent and highly specific antibodies are mandatory.
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Affiliation(s)
- Wesley L Fotoran
- Department of Parasitology, Institute for Biomedical Sciences, University of São Paulo, Av. Prof. Lineu Prestes 1374, São Paulo, 05508000, Brazil
| | - Rachele Santangelo
- Department of Parasitology, Institute for Biomedical Sciences, University of São Paulo, Av. Prof. Lineu Prestes 1374, São Paulo, 05508000, Brazil
| | - Beatriz N M de Miranda
- Institute of Chemistry of São Carlos, University of São Paulo, Av. Trabalhador São-Carlense 400, São Carlos, 13566-590, Brazil
| | - Darrell J Irvine
- Koch Institute for Integrative Cancer Research and Department of Biomedical Engineering and Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA.,Ragon Institute of MGH, MIT and Harvard University, Boston, MA, USA.,Howard Hughes Medical Institute, Chevy Chase, MD, USA
| | - Gerhard Wunderlich
- Department of Parasitology, Institute for Biomedical Sciences, University of São Paulo, Av. Prof. Lineu Prestes 1374, São Paulo, 05508000, Brazil
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38
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Othman AS, Marin-Mogollon C, Salman AM, Franke-Fayard BM, Janse CJ, Khan SM. The use of transgenic parasites in malaria vaccine research. Expert Rev Vaccines 2017; 16:1-13. [DOI: 10.1080/14760584.2017.1333426] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Ahmad Syibli Othman
- Leiden Malaria Research Group, Parasitology, Leiden University Medical Center (LUMC), Leiden, the Netherlands
- Faculty of Health Sciences, Universiti Sultan Zainal Abidin, Terengganu, Malaysia
| | - Catherin Marin-Mogollon
- Leiden Malaria Research Group, Parasitology, Leiden University Medical Center (LUMC), Leiden, the Netherlands
| | | | - Blandine M. Franke-Fayard
- Leiden Malaria Research Group, Parasitology, Leiden University Medical Center (LUMC), Leiden, the Netherlands
| | - Chris J. Janse
- Leiden Malaria Research Group, Parasitology, Leiden University Medical Center (LUMC), Leiden, the Netherlands
| | - Shahid M. Khan
- Leiden Malaria Research Group, Parasitology, Leiden University Medical Center (LUMC), Leiden, the Netherlands
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39
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Kennedy AT, Wijeyewickrema LC, Huglo A, Lin C, Pike R, Cowman AF, Tham WH. Recruitment of Human C1 Esterase Inhibitor Controls Complement Activation on Blood StagePlasmodium falciparumMerozoites. THE JOURNAL OF IMMUNOLOGY 2017; 198:4728-4737. [DOI: 10.4049/jimmunol.1700067] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 04/10/2017] [Indexed: 11/19/2022]
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40
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Counihan NA, Chisholm SA, Bullen HE, Srivastava A, Sanders PR, Jonsdottir TK, Weiss GE, Ghosh S, Crabb BS, Creek DJ, Gilson PR, de Koning-Ward TF. Plasmodium falciparum parasites deploy RhopH2 into the host erythrocyte to obtain nutrients, grow and replicate. eLife 2017; 6. [PMID: 28252383 PMCID: PMC5365316 DOI: 10.7554/elife.23217] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2016] [Accepted: 02/26/2017] [Indexed: 11/13/2022] Open
Abstract
Plasmodium falciparum parasites, the causative agents of malaria, modify their host erythrocyte to render them permeable to supplementary nutrient uptake from the plasma and for removal of toxic waste. Here we investigate the contribution of the rhoptry protein RhopH2, in the formation of new permeability pathways (NPPs) in Plasmodium-infected erythrocytes. We show RhopH2 interacts with RhopH1, RhopH3, the erythrocyte cytoskeleton and exported proteins involved in host cell remodeling. Knockdown of RhopH2 expression in cycle one leads to a depletion of essential vitamins and cofactors and decreased de novo synthesis of pyrimidines in cycle two. There is also a significant impact on parasite growth, replication and transition into cycle three. The uptake of solutes that use NPPs to enter erythrocytes is also reduced upon RhopH2 knockdown. These findings provide direct genetic support for the contribution of the RhopH complex in NPP activity and highlight the importance of NPPs to parasite survival.
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Affiliation(s)
| | | | | | - Anubhav Srivastava
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Australia
| | | | - Thorey K Jonsdottir
- Burnet Institute, Melbourne, Australia.,Department of Medicine, University of Melbourne, Parkville, Australia
| | | | - Sreejoyee Ghosh
- School of Medicine, Deakin University, Waurn Ponds, Australia
| | - Brendan S Crabb
- Burnet Institute, Melbourne, Australia.,Department of Medicine, University of Melbourne, Parkville, Australia.,Monash University, Melbourne, Australia
| | - Darren J Creek
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Australia
| | - Paul R Gilson
- Burnet Institute, Melbourne, Australia.,Monash University, Melbourne, Australia
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41
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Johnson S, Rahmani R, Drew DR, Williams MJ, Wilkinson M, Tan YH, Huang JX, Tonkin CJ, Beeson JG, Baum J, Smith BJ, Baell JB. Truncated Latrunculins as Actin Inhibitors Targeting Plasmodium falciparum Motility and Host Cell Invasion. J Med Chem 2016; 59:10994-11005. [PMID: 28002959 DOI: 10.1021/acs.jmedchem.6b01109] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Polymerization of the cytosolic protein actin is critical to cell movement and host cell invasion by the malaria parasite, Plasmodium falciparum. Any disruption to actin polymerization dynamics will render the parasite incapable of invading a host cell and thereby unable to cause infection. Here, we explore the potential of using truncated latrunculins as potential chemotherapeutics for the treatment of malaria. Exploration of the binding interactions of the natural actin inhibitor latrunculins with actin revealed how a truncated core of the inhibitor could retain its key interaction features with actin. This truncated core was synthesized and subjected to preliminary structure-activity relationship studies to generate a focused set of analogues. Biochemical analyses of these analogues demonstrate their 6-fold increased activity compared with that of latrunculin B against P. falciparum and a 16-fold improved selectivity ex vivo. These data establish the latrunculin core as a potential focus for future structure-based drug design of chemotherapeutics against malaria.
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Affiliation(s)
- Swapna Johnson
- La Trobe Institute for Molecular Science, La Trobe University , Melbourne, Victoria 3086, Australia.,Monash Institute of Pharmaceutical Sciences, Monash University , Parkville, Victoria 3052, Australia
| | - Raphaël Rahmani
- Monash Institute of Pharmaceutical Sciences, Monash University , Parkville, Victoria 3052, Australia
| | - Damien R Drew
- Burnet Institute , 85 Commercial Rd, Melbourne Victoria 3004, Australia.,Central Clinical School and Department of Microbiology, Monash University , Melbourne, Victoria 3004, Australia
| | - Melanie J Williams
- Walter and Eliza Hall Institute , 1G Royal Parade, Parkville, Victoria 3052, Australia.,The Department of Medical Biology, The University of Melbourne , Melbourne, Victoria 3010, Australia
| | - Mark Wilkinson
- Department of Life Sciences, Imperial College London , South Kensington SW7 2AZ, United Kingdom
| | - Yan Hong Tan
- Walter and Eliza Hall Institute , 1G Royal Parade, Parkville, Victoria 3052, Australia.,Department of Life Sciences, Imperial College London , South Kensington SW7 2AZ, United Kingdom
| | - Johnny X Huang
- Institute for Molecular Bioscience, The University of Queensland , St Lucia, Queensland 4072, Australia
| | - Christopher J Tonkin
- Walter and Eliza Hall Institute , 1G Royal Parade, Parkville, Victoria 3052, Australia.,The Department of Medical Biology, The University of Melbourne , Melbourne, Victoria 3010, Australia
| | - James G Beeson
- Burnet Institute , 85 Commercial Rd, Melbourne Victoria 3004, Australia.,Central Clinical School and Department of Microbiology, Monash University , Melbourne, Victoria 3004, Australia
| | - Jake Baum
- Walter and Eliza Hall Institute , 1G Royal Parade, Parkville, Victoria 3052, Australia.,Department of Life Sciences, Imperial College London , South Kensington SW7 2AZ, United Kingdom
| | - Brian J Smith
- La Trobe Institute for Molecular Science, La Trobe University , Melbourne, Victoria 3086, Australia
| | - Jonathan B Baell
- Monash Institute of Pharmaceutical Sciences, Monash University , Parkville, Victoria 3052, Australia
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42
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Drew DR, Wilson DW, Elliott SR, Cross N, Terheggen U, Hodder AN, Siba PM, Chelimo K, Dent AE, Kazura JW, Mueller I, Beeson JG. A novel approach to identifying patterns of human invasion-inhibitory antibodies guides the design of malaria vaccines incorporating polymorphic antigens. BMC Med 2016; 14:144. [PMID: 27658419 PMCID: PMC5034621 DOI: 10.1186/s12916-016-0691-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Accepted: 09/08/2016] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND The polymorphic nature of many malaria vaccine candidates presents major challenges to achieving highly efficacious vaccines. Presently, there is very little knowledge on the prevalence and patterns of functional immune responses to polymorphic vaccine candidates in populations to guide vaccine design. A leading polymorphic vaccine candidate against blood-stage Plasmodium falciparum is apical membrane antigen 1 (AMA1), which is essential for erythrocyte invasion. The importance of AMA1 as a target of acquired human inhibitory antibodies, their allele specificity and prevalence in populations is unknown, but crucial for vaccine design. METHODS P. falciparum lines expressing different AMA1 alleles were genetically engineered and used to quantify functional antibodies from two malaria-exposed populations of adults and children. The acquisition of AMA1 antibodies was also detected using enzyme-linked immunosorbent assay (ELISA) and competition ELISA (using different AMA1 alleles) from the same populations. RESULTS We found that AMA1 was a major target of naturally acquired invasion-inhibitory antibodies that were highly prevalent in malaria-endemic populations and showed a high degree of allele specificity. Significantly, the prevalence of inhibitory antibodies to different alleles varied substantially within populations and between geographic locations. Inhibitory antibodies to three specific alleles were highly prevalent (FVO and W2mef in Papua New Guinea; FVO and XIE in Kenya), identifying them for potential vaccine inclusion. Measurement of antibodies by standard or competition ELISA was not strongly predictive of allele-specific inhibitory antibodies. The patterns of allele-specific functional antibody responses detected with our novel assays may indicate that acquired immunity is elicited towards serotypes that are prevalent in each geographic location. CONCLUSIONS These findings provide new insights into the nature and acquisition of functional immunity to a polymorphic vaccine candidate and strategies to quantify functional immunity in populations to guide rational vaccine design.
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Affiliation(s)
- Damien R Drew
- The Burnet Institute of Medical Research and Public Health, 85 Commercial Road, Melbourne, Victoria, 3004, Australia
| | - Danny W Wilson
- The Burnet Institute of Medical Research and Public Health, 85 Commercial Road, Melbourne, Victoria, 3004, Australia.,Research Centre for Infectious Diseases, School of Molecular and Biomedical Science, University of Adelaide, Adelaide, South Australia, Australia
| | - Salenna R Elliott
- The Burnet Institute of Medical Research and Public Health, 85 Commercial Road, Melbourne, Victoria, 3004, Australia
| | - Nadia Cross
- The Burnet Institute of Medical Research and Public Health, 85 Commercial Road, Melbourne, Victoria, 3004, Australia
| | - Ulrich Terheggen
- The Burnet Institute of Medical Research and Public Health, 85 Commercial Road, Melbourne, Victoria, 3004, Australia.,Department of Medicine, Royal Melbourne Hospital, University of Melbourne, Parkville, Victoria, Australia
| | - Anthony N Hodder
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
| | - Peter M Siba
- Papua New Guinea Institute of Medical Research, Goroka, Papua New Guinea
| | | | - Arlene E Dent
- Case Western Reserve University, Cleveland, Ohio, USA
| | | | - Ivo Mueller
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
| | - James G Beeson
- The Burnet Institute of Medical Research and Public Health, 85 Commercial Road, Melbourne, Victoria, 3004, Australia. .,Department of Medicine, Royal Melbourne Hospital, University of Melbourne, Parkville, Victoria, Australia. .,Department of Microbiology, Monash University, Clayton, Victoria, Australia.
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43
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Boyle MJ, Reiling L, Osier FH, Fowkes FJI. Recent insights into humoral immunity targeting Plasmodium falciparum and Plasmodium vivax malaria. Int J Parasitol 2016; 47:99-104. [PMID: 27451359 DOI: 10.1016/j.ijpara.2016.06.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Revised: 06/08/2016] [Accepted: 06/09/2016] [Indexed: 01/02/2023]
Abstract
Recent efforts in malaria control have led to marked reductions in malaria incidence. However, new strategies are needed to sustain malaria elimination and eradication and achieve the World Health Organization goal of a malaria-free world. The development of highly effective vaccines would contribute to this goal and would be facilitated by a comprehensive understanding of humoral immune responses targeting Plasmodium falciparum and Plasmodium vivax malaria. New tools are required to facilitate the identification of vaccine candidates and the development of vaccines that induce functional and protective immunity. Here we discuss recent published findings, and unpublished work presented at the 2016 Molecular Approaches to Malaria conference, that highlight advancements in understanding humoral immune responses in the context of vaccine development. Highlights include the increased application of 'omics' and 'Big data' platforms to identify vaccine candidates, and the identification of novel functions of antibody responses that mediate protection. The application of these strategies and a global approach will increase the likelihood of rapid development of highly efficacious vaccines.
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Affiliation(s)
- Michelle J Boyle
- Burnet Institute for Medical Research and Public Health, Melbourne, Victoria 3004, Australia; Menzies School of Medical Research, Darwin, Northern Territory 0810, Australia.
| | - Linda Reiling
- Burnet Institute for Medical Research and Public Health, Melbourne, Victoria 3004, Australia
| | - Faith H Osier
- KEMRI Centre for Geographic Medicine Research-Coast, Kilifi, Kenya
| | - Freya J I Fowkes
- Burnet Institute for Medical Research and Public Health, Melbourne, Victoria 3004, Australia; Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, Victoria 3010, Australia; Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Victoria 3004, Australia; Department of Infectious Diseases, Monash University, Melbourne, Victoria 3004, Australia
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44
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Quantitative phospho-proteomics reveals the Plasmodium merozoite triggers pre-invasion host kinase modification of the red cell cytoskeleton. Sci Rep 2016; 6:19766. [PMID: 26830761 PMCID: PMC4735681 DOI: 10.1038/srep19766] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Accepted: 12/17/2015] [Indexed: 01/27/2023] Open
Abstract
The invasive blood-stage malaria parasite - the merozoite - induces rapid morphological changes to the target erythrocyte during entry. However, evidence for active molecular changes in the host cell that accompany merozoite invasion is lacking. Here, we use invasion inhibition assays, erythrocyte resealing and high-definition imaging to explore red cell responses during invasion. We show that although merozoite entry does not involve erythrocyte actin reorganisation, it does require ATP to complete the process. Towards dissecting the ATP requirement, we present an in depth quantitative phospho-proteomic analysis of the erythrocyte during each stage of invasion. Specifically, we demonstrate extensive increased phosphorylation of erythrocyte proteins on merozoite attachment, including modification of the cytoskeletal proteins beta-spectrin and PIEZO1. The association with merozoite contact but not active entry demonstrates that parasite-dependent phosphorylation is mediated by host-cell kinase activity. This provides the first evidence that the erythrocyte is stimulated to respond to early invasion events through molecular changes in its membrane architecture.
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45
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Pérez-Moreno G, Cantizani J, Sánchez-Carrasco P, Ruiz-Pérez LM, Martín J, el Aouad N, Pérez-Victoria I, Tormo JR, González-Menendez V, González I, de Pedro N, Reyes F, Genilloud O, Vicente F, González-Pacanowska D. Discovery of New Compounds Active against Plasmodium falciparum by High Throughput Screening of Microbial Natural Products. PLoS One 2016; 11:e0145812. [PMID: 26735308 PMCID: PMC4703298 DOI: 10.1371/journal.pone.0145812] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Accepted: 12/09/2015] [Indexed: 12/03/2022] Open
Abstract
Due to the low structural diversity within the set of antimalarial drugs currently available in the clinic and the increasing number of cases of resistance, there is an urgent need to find new compounds with novel modes of action to treat the disease. Microbial natural products are characterized by their large diversity provided in terms of the chemical complexity of the compounds and the novelty of structures. Microbial natural products extracts have been underexplored in the search for new antiparasitic drugs and even more so in the discovery of new antimalarials. Our objective was to find new druggable natural products with antimalarial properties from the MEDINA natural products collection, one of the largest natural product libraries harboring more than 130,000 microbial extracts. In this work, we describe the optimization process and the results of a phenotypic high throughput screen (HTS) based on measurements of Plasmodium lactate dehydrogenase. A subset of more than 20,000 extracts from the MEDINA microbial products collection has been explored, leading to the discovery of 3 new compounds with antimalarial activity. In addition, we report on the novel antiplasmodial activity of 4 previously described natural products.
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Affiliation(s)
- Guiomar Pérez-Moreno
- Instituto de Parasitología y Biomedicina “López-Neyra”, Consejo Superior de Investigaciones Científicas, Parque Tecnológico de Ciencias de la Salud, Avenida del Conocimiento, s/n, 18016-Armilla (Granada), Spain
| | - Juan Cantizani
- Fundación MEDINA, Parque Tecnológico de Ciencias de la Salud, Avenida del Conocimiento, 34.18016-Armilla (Granada), Spain
| | - Paula Sánchez-Carrasco
- Instituto de Parasitología y Biomedicina “López-Neyra”, Consejo Superior de Investigaciones Científicas, Parque Tecnológico de Ciencias de la Salud, Avenida del Conocimiento, s/n, 18016-Armilla (Granada), Spain
| | - Luis Miguel Ruiz-Pérez
- Instituto de Parasitología y Biomedicina “López-Neyra”, Consejo Superior de Investigaciones Científicas, Parque Tecnológico de Ciencias de la Salud, Avenida del Conocimiento, s/n, 18016-Armilla (Granada), Spain
| | - Jesús Martín
- Fundación MEDINA, Parque Tecnológico de Ciencias de la Salud, Avenida del Conocimiento, 34.18016-Armilla (Granada), Spain
| | - Noureddine el Aouad
- Fundación MEDINA, Parque Tecnológico de Ciencias de la Salud, Avenida del Conocimiento, 34.18016-Armilla (Granada), Spain
| | - Ignacio Pérez-Victoria
- Fundación MEDINA, Parque Tecnológico de Ciencias de la Salud, Avenida del Conocimiento, 34.18016-Armilla (Granada), Spain
| | - José Rubén Tormo
- Fundación MEDINA, Parque Tecnológico de Ciencias de la Salud, Avenida del Conocimiento, 34.18016-Armilla (Granada), Spain
| | - Víctor González-Menendez
- Fundación MEDINA, Parque Tecnológico de Ciencias de la Salud, Avenida del Conocimiento, 34.18016-Armilla (Granada), Spain
| | - Ignacio González
- Fundación MEDINA, Parque Tecnológico de Ciencias de la Salud, Avenida del Conocimiento, 34.18016-Armilla (Granada), Spain
| | - Nuria de Pedro
- Fundación MEDINA, Parque Tecnológico de Ciencias de la Salud, Avenida del Conocimiento, 34.18016-Armilla (Granada), Spain
| | - Fernando Reyes
- Fundación MEDINA, Parque Tecnológico de Ciencias de la Salud, Avenida del Conocimiento, 34.18016-Armilla (Granada), Spain
| | - Olga Genilloud
- Fundación MEDINA, Parque Tecnológico de Ciencias de la Salud, Avenida del Conocimiento, 34.18016-Armilla (Granada), Spain
| | - Francisca Vicente
- Fundación MEDINA, Parque Tecnológico de Ciencias de la Salud, Avenida del Conocimiento, 34.18016-Armilla (Granada), Spain
| | - Dolores González-Pacanowska
- Instituto de Parasitología y Biomedicina “López-Neyra”, Consejo Superior de Investigaciones Científicas, Parque Tecnológico de Ciencias de la Salud, Avenida del Conocimiento, s/n, 18016-Armilla (Granada), Spain
- * E-mail:
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Kennedy AT, Schmidt CQ, Thompson JK, Weiss GE, Taechalertpaisarn T, Gilson PR, Barlow PN, Crabb BS, Cowman AF, Tham WH. Recruitment of Factor H as a Novel Complement Evasion Strategy for Blood-Stage Plasmodium falciparum Infection. THE JOURNAL OF IMMUNOLOGY 2015; 196:1239-48. [PMID: 26700768 DOI: 10.4049/jimmunol.1501581] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Accepted: 11/23/2015] [Indexed: 01/29/2023]
Abstract
The human complement system is the frontline defense mechanism against invading pathogens. The coexistence of humans and microbes throughout evolution has produced ingenious molecular mechanisms by which microorganisms escape complement attack. A common evasion strategy used by diverse pathogens is the hijacking of soluble human complement regulators to their surfaces to afford protection from complement activation. One such host regulator is factor H (FH), which acts as a negative regulator of complement to protect host tissues from aberrant complement activation. In this report, we show that Plasmodium falciparum merozoites, the invasive form of the malaria parasites, actively recruit FH and its alternative spliced form FH-like protein 1 when exposed to human serum. We have mapped the binding site in FH that recognizes merozoites and identified Pf92, a member of the six-cysteine family of Plasmodium surface proteins, as its direct interaction partner. When bound to merozoites, FH retains cofactor activity, a key function that allows it to downregulate the alternative pathway of complement. In P. falciparum parasites that lack Pf92, we observed changes in the pattern of C3b cleavage that are consistent with decreased regulation of complement activation. These results also show that recruitment of FH affords P. falciparum merozoites protection from complement-mediated lysis. Our study provides new insights on mechanisms of immune evasion of malaria parasites and highlights the important function of surface coat proteins in the interplay between complement regulation and successful infection of the host.
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Affiliation(s)
- Alexander T Kennedy
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria 3052, Australia
| | - Christoph Q Schmidt
- Institute of Pharmacology of Natural Products and Clinical Pharmacology, Ulm University, 89081 Ulm, Germany
| | - Jennifer K Thompson
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia
| | - Greta E Weiss
- Burnet Institute, Melbourne, Victoria 3004, Australia
| | | | - Paul R Gilson
- Burnet Institute, Melbourne, Victoria 3004, Australia; Department of Immunology, Monash University, Victoria 3004, Australia
| | - Paul N Barlow
- School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FF, United Kingdom; School of Chemistry, University of Edinburgh, Edinburgh EH9 3FJ, United Kingdom; and
| | - Brendan S Crabb
- Burnet Institute, Melbourne, Victoria 3004, Australia; Department of Immunology, Monash University, Victoria 3004, Australia; Department of Microbiology and Immunology, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Alan F Cowman
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria 3052, Australia
| | - Wai-Hong Tham
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria 3052, Australia;
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47
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Lim NTY, Harder MJ, Kennedy AT, Lin CS, Weir C, Cowman AF, Call MJ, Schmidt CQ, Tham WH. Characterization of Inhibitors and Monoclonal Antibodies That Modulate the Interaction between Plasmodium falciparum Adhesin PfRh4 with Its Erythrocyte Receptor Complement Receptor 1. J Biol Chem 2015; 290:25307-21. [PMID: 26324715 DOI: 10.1074/jbc.m115.657171] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Indexed: 11/06/2022] Open
Abstract
Plasmodium falciparum parasites must invade red blood cells to survive within humans. Entry into red blood cells is governed by interactions between parasite adhesins and red blood cell receptors. Previously we identified that P. falciparum reticulocyte binding protein-like homologue 4 (PfRh4) binds to complement receptor 1 (CR1) to mediate entry of malaria parasites into human red blood cells. In this report we characterize a collection of anti-PfRh4 monoclonal antibodies and CR1 protein fragments that modulate the interaction between PfRh4 and CR1. We identify an anti-PfRh4 monoclonal that blocks PfRh4-CR1 interaction in vitro, inhibits PfRh4 binding to red blood cells, and as a result abolishes the PfRh4-CR1 invasion pathway in P. falciparum. Epitope mapping of anti-PfRh4 monoclonal antibodies identified distinct functional regions within PfRh4 involved in modulating its interaction with CR1. Furthermore, we designed a set of protein fragments based on extensive mutagenesis analyses of the PfRh4 binding site on CR1 and determined their interaction affinities using surface plasmon resonance. These CR1 protein fragments bind tightly to PfRh4 and also function as soluble inhibitors to block PfRh4 binding to red blood cells and to inhibit the PfRh4-CR1 invasion pathway. Our findings can aid future efforts in designing specific single epitope antibodies to block P. falciparum invasion via complement receptor 1.
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Affiliation(s)
- Nicholas T Y Lim
- From the Walter and Eliza Hall Institute, Parkville, Victoria 3052, Australia
| | - Markus J Harder
- the Institute of Pharmacology of Natural Products and Clinical Pharmacology, Ulm University, Helmholtzstrasse 20, D-89081 Ulm, Germany
| | - Alexander T Kennedy
- From the Walter and Eliza Hall Institute, Parkville, Victoria 3052, Australia, the Department of Medical Biology, University of Melbourne, Parkville, Victoria 3052, Australia, and
| | - Clara S Lin
- From the Walter and Eliza Hall Institute, Parkville, Victoria 3052, Australia, the Department of Medical Biology, University of Melbourne, Parkville, Victoria 3052, Australia, and
| | - Christopher Weir
- From the Walter and Eliza Hall Institute, Parkville, Victoria 3052, Australia, the Department of Medical Biology, University of Melbourne, Parkville, Victoria 3052, Australia, and the School of Chemistry, University of Edinburgh, Edinburgh EH93JJ, Scotland, United Kingdom
| | - Alan F Cowman
- From the Walter and Eliza Hall Institute, Parkville, Victoria 3052, Australia, the Department of Medical Biology, University of Melbourne, Parkville, Victoria 3052, Australia, and
| | - Melissa J Call
- From the Walter and Eliza Hall Institute, Parkville, Victoria 3052, Australia, the Department of Medical Biology, University of Melbourne, Parkville, Victoria 3052, Australia, and
| | - Christoph Q Schmidt
- the Institute of Pharmacology of Natural Products and Clinical Pharmacology, Ulm University, Helmholtzstrasse 20, D-89081 Ulm, Germany
| | - Wai-Hong Tham
- From the Walter and Eliza Hall Institute, Parkville, Victoria 3052, Australia, the Department of Medical Biology, University of Melbourne, Parkville, Victoria 3052, Australia, and
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48
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Wilson DW, Goodman CD, Sleebs BE, Weiss GE, de Jong NW, Angrisano F, Langer C, Baum J, Crabb BS, Gilson PR, McFadden GI, Beeson JG. Macrolides rapidly inhibit red blood cell invasion by the human malaria parasite, Plasmodium falciparum. BMC Biol 2015; 13:52. [PMID: 26187647 PMCID: PMC4506589 DOI: 10.1186/s12915-015-0162-0] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Accepted: 06/30/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Malaria invasion of red blood cells involves multiple parasite-specific targets that are easily accessible to inhibitory compounds, making it an attractive target for antimalarial development. However, no current antimalarial agents act against host cell invasion. RESULTS Here, we demonstrate that the clinically used macrolide antibiotic azithromycin, which is known to kill human malaria asexual blood-stage parasites by blocking protein synthesis in their apicoplast, is also a rapid inhibitor of red blood cell invasion in human (Plasmodium falciparum) and rodent (P. berghei) malarias. Multiple lines of evidence demonstrate that the action of azithromycin in inhibiting parasite invasion of red blood cells is independent of its inhibition of protein synthesis in the parasite apicoplast, opening up a new strategy to develop a single drug with multiple parasite targets. We identified derivatives of azithromycin and erythromycin that are better invasion inhibitors than parent compounds, offering promise for development of this novel antimalarial strategy. CONCLUSIONS Safe and effective macrolide antibiotics with dual modalities could be developed to combat malaria and reduce the parasite's options for resistance.
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Affiliation(s)
- Danny W Wilson
- Research Centre for Infectious Diseases, School of Biological Sciences, The University of Adelaide, Adelaide, South Australia. .,Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, 3050, Australia. .,Department of Medical Biology, University of Melbourne, Parkville, Victoria, 3050, Australia. .,Macfarlane Burnet Institute for Medical Research and Public Health, Melbourne, Victoria, 3004, Australia.
| | - Christopher D Goodman
- Plant Cell Biology Research Centre, School of Biosciences, University of Melbourne, Parkville, Victoria, 3010, Australia.
| | - Brad E Sleebs
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, 3050, Australia. .,Department of Medical Biology, University of Melbourne, Parkville, Victoria, 3050, Australia.
| | - Greta E Weiss
- Macfarlane Burnet Institute for Medical Research and Public Health, Melbourne, Victoria, 3004, Australia.
| | - Nienke Wm de Jong
- Macfarlane Burnet Institute for Medical Research and Public Health, Melbourne, Victoria, 3004, Australia.
| | - Fiona Angrisano
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, 3050, Australia. .,Department of Medical Biology, University of Melbourne, Parkville, Victoria, 3050, Australia. .,Department of Life Sciences, Imperial College London, South Kensington, London, SW7 2AZ, UK.
| | - Christine Langer
- Macfarlane Burnet Institute for Medical Research and Public Health, Melbourne, Victoria, 3004, Australia.
| | - Jake Baum
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, 3050, Australia. .,Department of Medical Biology, University of Melbourne, Parkville, Victoria, 3050, Australia. .,Department of Life Sciences, Imperial College London, South Kensington, London, SW7 2AZ, UK.
| | - Brendan S Crabb
- Department of Medical Biology, University of Melbourne, Parkville, Victoria, 3050, Australia. .,Macfarlane Burnet Institute for Medical Research and Public Health, Melbourne, Victoria, 3004, Australia. .,Department of Immunology, Monash University, Clayton, Victoria, 3800, Australia.
| | - Paul R Gilson
- Macfarlane Burnet Institute for Medical Research and Public Health, Melbourne, Victoria, 3004, Australia. .,Department of Immunology, Monash University, Clayton, Victoria, 3800, Australia.
| | - Geoffrey I McFadden
- Plant Cell Biology Research Centre, School of Biosciences, University of Melbourne, Parkville, Victoria, 3010, Australia.
| | - James G Beeson
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, 3050, Australia. .,Macfarlane Burnet Institute for Medical Research and Public Health, Melbourne, Victoria, 3004, Australia. .,Department of Microbiology, Monash University, Clayton, Victoria, 3168, Australia.
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49
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Boyle MJ, Reiling L, Feng G, Langer C, Osier FH, Aspeling-Jones H, Cheng YS, Stubbs J, Tetteh KKA, Conway DJ, McCarthy JS, Muller I, Marsh K, Anders RF, Beeson JG. Human antibodies fix complement to inhibit Plasmodium falciparum invasion of erythrocytes and are associated with protection against malaria. Immunity 2015; 42:580-90. [PMID: 25786180 PMCID: PMC4372259 DOI: 10.1016/j.immuni.2015.02.012] [Citation(s) in RCA: 217] [Impact Index Per Article: 24.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2014] [Revised: 12/01/2014] [Accepted: 02/23/2015] [Indexed: 11/26/2022]
Abstract
Antibodies play major roles in immunity to malaria; however, a limited understanding of mechanisms mediating protection is a major barrier to vaccine development. We have demonstrated that acquired human anti-malarial antibodies promote complement deposition on the merozoite to mediate inhibition of erythrocyte invasion through C1q fixation and activation of the classical complement pathway. Antibody-mediated complement-dependent (Ab-C′) inhibition was the predominant invasion-inhibitory activity of human antibodies; most antibodies were non-inhibitory without complement. Inhibitory activity was mediated predominately via C1q fixation, and merozoite surface proteins 1 and 2 were identified as major targets. Complement fixation by antibodies was very strongly associated with protection from both clinical malaria and high-density parasitemia in a prospective longitudinal study of children. Ab-C′ inhibitory activity could be induced by human immunization with a candidate merozoite surface-protein vaccine. Our findings demonstrate that human anti-malarial antibodies have evolved to function by fixing complement for potent invasion-inhibitory activity and protective immunity. Antibodies function with complement to inhibit P. falciparum replication Antibodies fix C1q to block invasion and lyse merozoites Complement-fixing antibodies are strongly associated with immunity in children Antibody-complement inhibition can be induced by human vaccination
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Affiliation(s)
- Michelle J Boyle
- The Burnet Institute for Medical Research and Public Health, 85 Commercial Road, Melbourne, VIC 3004, Australia; Department of Medical Biology, University of Melbourne, Royal Parade, Melbourne, VIC 3010, Australia
| | - Linda Reiling
- The Burnet Institute for Medical Research and Public Health, 85 Commercial Road, Melbourne, VIC 3004, Australia
| | - Gaoqian Feng
- The Burnet Institute for Medical Research and Public Health, 85 Commercial Road, Melbourne, VIC 3004, Australia
| | - Christine Langer
- The Burnet Institute for Medical Research and Public Health, 85 Commercial Road, Melbourne, VIC 3004, Australia
| | - Faith H Osier
- Centre for Geographic Medicine Research, Kenya Medical Research Institute, Coast, PO Box 230, 80108 Kilifi, Kenya
| | | | - Yik Sheng Cheng
- The Burnet Institute for Medical Research and Public Health, 85 Commercial Road, Melbourne, VIC 3004, Australia; Department of Medical Biology, University of Melbourne, Royal Parade, Melbourne, VIC 3010, Australia
| | - Janine Stubbs
- The Burnet Institute for Medical Research and Public Health, 85 Commercial Road, Melbourne, VIC 3004, Australia
| | - Kevin K A Tetteh
- London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E7HT, UK
| | - David J Conway
- London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E7HT, UK
| | - James S McCarthy
- QIMR Berghofer Medical Research Institute, University of Queensland, 300 Herston Road, Herston, QLD 4006, Australia
| | - Ivo Muller
- Walter and Eliza Hall Institute, Royal Parade, Melbourne, VIC 3050, Australia
| | - Kevin Marsh
- Centre for Geographic Medicine Research, Kenya Medical Research Institute, Coast, PO Box 230, 80108 Kilifi, Kenya
| | - Robin F Anders
- Department of Biochemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC 3086, Australia
| | - James G Beeson
- The Burnet Institute for Medical Research and Public Health, 85 Commercial Road, Melbourne, VIC 3004, Australia; Department of Microbiology, Monash University, Clayton, VIC 3800, Australia.
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50
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Webster WAJ, McFadden GI. From the genome to the phenome: tools to understand the basic biology of Plasmodium falciparum. J Eukaryot Microbiol 2014; 61:655-71. [PMID: 25227912 DOI: 10.1111/jeu.12176] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Revised: 09/01/2014] [Accepted: 09/02/2014] [Indexed: 11/30/2022]
Abstract
Malaria plagues one out of every 30 humans and contributes to almost a million deaths, and the problem could worsen. Our current therapeutic options are compromised by emerging resistance by the parasite to our front line drugs. It is thus imperative to better understand the basic biology of the parasite and develop novel drugs to stem this disease. The most facile approach to analyse a gene's function is to remove it from the genome or inhibit its activity. Although genetic manipulation of the human malaria parasite Plasmodium falciparum is a relatively standard procedure, there is no optimal method to perturb genes essential to the intraerythrocytic development cycle--the part of the life cycle that produces the clinical manifestation of malaria. This is a severe impediment to progress because the phenotype we wish to study is exactly the one that is so elusive. In the absence of any utilitarian way to conditionally delete essential genes, we are prevented from investigating the parasite's most vulnerable points. This review aims to focus on the development of tools identifying essential genes of P. falciparum and our ability to elicit phenotypic mutation.
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Affiliation(s)
- Wesley A J Webster
- Centre for Regional and Rural Futures, School of Life and Environmental Sciences, Deakin University, Burwood, 3125, Victoria, Australia; Plant Cell Biology Research Centre, School of Botany, University of Melbourne, Melbourne, 3010, Victoria, Australia
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