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Elsworth B, Keroack C, Rezvani Y, Paul A, Barazorda K, Tennessen J, Sack S, Moreira C, Gubbels MJ, Meyers M, Zarringhalam K, Duraisingh M. Babesia divergens egress from host cells is orchestrated by essential and druggable kinases and proteases. RESEARCH SQUARE 2023:rs.3.rs-2553721. [PMID: 36909484 PMCID: PMC10002801 DOI: 10.21203/rs.3.rs-2553721/v1] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/04/2023]
Abstract
Apicomplexan egress from host cells is fundamental to the spread of infection and is poorly characterized in Babesia spp., parasites of veterinary importance and emerging zoonoses. Through the use of video microscopy, transcriptomics and chemical genetics, we have implicated signaling, proteases and gliding motility as key drivers of egress by Babesia divergens. We developed reverse genetics to perform a knockdown screen of putative mediators of egress, identifying kinases and proteases involved in distinct steps of egress (ASP3, PKG and CDPK4) and invasion (ASP2, ASP3 and PKG). Inhibition of egress leads to continued intracellular replication, indicating exit from the replication cycle is uncoupled from egress. Chemical genetics validated PKG, ASP2 and ASP3 as druggable targets in Babesia spp. All taken together, egress in B. divergens more closely resembles T. gondii than the more evolutionarily-related Plasmodium spp. We have established a molecular framework for biological and translational studies of B. divergens egress.
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2
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Molina-Franky J, Patarroyo ME, Kalkum M, Patarroyo MA. The Cellular and Molecular Interaction Between Erythrocytes and Plasmodium falciparum Merozoites. Front Cell Infect Microbiol 2022; 12:816574. [PMID: 35433504 PMCID: PMC9008539 DOI: 10.3389/fcimb.2022.816574] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 02/21/2022] [Indexed: 11/13/2022] Open
Abstract
Plasmodium falciparum is the most lethal human malaria parasite, partly due to its genetic variability and ability to use multiple invasion routes via its binding to host cell surface receptors. The parasite extensively modifies infected red blood cell architecture to promote its survival which leads to increased cell membrane rigidity, adhesiveness and permeability. Merozoites are initially released from infected hepatocytes and efficiently enter red blood cells in a well-orchestrated process that involves specific interactions between parasite ligands and erythrocyte receptors; symptoms of the disease occur during the life-cycle’s blood stage due to capillary blockage and massive erythrocyte lysis. Several studies have focused on elucidating molecular merozoite/erythrocyte interactions and host cell modifications; however, further in-depth analysis is required for understanding the parasite’s biology and thus provide the fundamental tools for developing prophylactic or therapeutic alternatives to mitigate or eliminate Plasmodium falciparum-related malaria. This review focuses on the cellular and molecular events during Plasmodium falciparum merozoite invasion of red blood cells and the alterations that occur in an erythrocyte once it has become infected.
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Affiliation(s)
- Jessica Molina-Franky
- Molecular Biology and Immunology Department, Fundación Instituto de Inmunología de Colombia (FIDIC), Bogotá, Colombia
- Department of Immunology and Theranostics, Arthur Riggs Diabetes and Metabolism Research Institute, Beckman Research Institute of the City of Hope, Duarte, CA, United States
- PhD Programme in Biotechnology, Universidad Nacional de Colombia, Bogotá, Colombia
| | - Manuel Elkin Patarroyo
- Molecular Biology and Immunology Department, Fundación Instituto de Inmunología de Colombia (FIDIC), Bogotá, Colombia
- Health Sciences Division, Universidad Santo Tomás, Bogotá, Colombia
- Faculty of Medicine, Universidad Nacional de Colombia, Bogotá, Colombia
| | - Markus Kalkum
- Department of Immunology and Theranostics, Arthur Riggs Diabetes and Metabolism Research Institute, Beckman Research Institute of the City of Hope, Duarte, CA, United States
- *Correspondence: Markus Kalkum, ; Manuel Alfonso Patarroyo,
| | - Manuel Alfonso Patarroyo
- Molecular Biology and Immunology Department, Fundación Instituto de Inmunología de Colombia (FIDIC), Bogotá, Colombia
- Health Sciences Division, Universidad Santo Tomás, Bogotá, Colombia
- Faculty of Medicine, Universidad Nacional de Colombia, Bogotá, Colombia
- *Correspondence: Markus Kalkum, ; Manuel Alfonso Patarroyo,
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3
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Kepple D, Pestana K, Tomida J, Abebe A, Golassa L, Lo E. Alternative Invasion Mechanisms and Host Immune Response to Plasmodium vivax Malaria: Trends and Future Directions. Microorganisms 2020; 9:E15. [PMID: 33374596 PMCID: PMC7822457 DOI: 10.3390/microorganisms9010015] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 12/19/2020] [Accepted: 12/21/2020] [Indexed: 11/21/2022] Open
Abstract
Plasmodium vivax malaria is a neglected tropical disease, despite being more geographically widespread than any other form of malaria. The documentation of P. vivax infections in different parts of Africa where Duffy-negative individuals are predominant suggested that there are alternative pathways for P. vivax to invade human erythrocytes. Duffy-negative individuals may be just as fit as Duffy-positive individuals and are no longer resistant to P.vivax malaria. In this review, we describe the complexity of P. vivax malaria, characterize pathogenesis and candidate invasion genes of P. vivax, and host immune responses to P. vivax infections. We provide a comprehensive review on parasite ligands in several Plasmodium species that further justify candidate genes in P. vivax. We also summarize previous genomic and transcriptomic studies related to the identification of ligand and receptor proteins in P. vivax erythrocyte invasion. Finally, we identify topics that remain unclear and propose future studies that will greatly contribute to our knowledge of P. vivax.
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Affiliation(s)
- Daniel Kepple
- Biological Sciences, University of North Carolina, Charlotte, NC 28223, USA; (K.P.); (J.T.)
| | - Kareen Pestana
- Biological Sciences, University of North Carolina, Charlotte, NC 28223, USA; (K.P.); (J.T.)
| | - Junya Tomida
- Biological Sciences, University of North Carolina, Charlotte, NC 28223, USA; (K.P.); (J.T.)
| | - Abnet Abebe
- Ethiopian Public Health Institute, Addis Ababa 1000, Ethiopia;
| | - Lemu Golassa
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa 1000, Ethiopia;
| | - Eugenia Lo
- Biological Sciences, University of North Carolina, Charlotte, NC 28223, USA; (K.P.); (J.T.)
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4
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Aniweh Y, Suurbaar J, Morang'a CM, Nyarko PB, Wright KE, Kusi KA, Ansah F, Kyei-Baafour E, Quansah E, Asante J, Thiam LG, Higgins MK, Awandare GA. Analysis of Plasmodium falciparum Rh2b deletion polymorphism across different transmission areas. Sci Rep 2020; 10:1498. [PMID: 32001728 PMCID: PMC6992740 DOI: 10.1038/s41598-020-58300-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Accepted: 01/14/2020] [Indexed: 11/12/2022] Open
Abstract
Despite significant progress in controlling malaria, the disease remains a global health burden. The intricate interactions the parasite Plasmodium falciparum has with its host allows it to grow and multiply in human erythrocytes. The mechanism by which P. falciparum merozoites invade human erythrocytes is complex, involving merozoite proteins as well as erythrocyte surface proteins. Members of the P. falciparum reticulocyte binding-like protein homolog (PfRh) family of proteins play a pivotal role in merozoite invasion and hence are important targets of immune responses. Domains within the PfRh2b protein have been implicated in its ability to stimulate natural protective antibodies in patients. More specifically, a 0.58 kbp deletion, at the C-terminus has been reported in high frequencies in Senegalese and Southeast Asian parasite populations, suggesting a possible role in immune evasion. We analysed 1218 P. falciparum clinical isolates, and the results show that this deletion is present in Ghanaian parasite populations (48.5% of all isolates), with Kintampo (hyper-endemic, 53.2%), followed by Accra (Hypo-endemic, 50.3%), Cape Coast (meso-endemic, 47.9%) and Sogakope (meso-endemic, 43.15%). Further analysis of parasite genomes stored in the MalariaGEN database revealed that the deletion variant was common across transmission areas globally, with an overall frequency of about 27.1%. Interestingly, some parasite isolates possessed mixed PfRh2b deletion and full-length alleles. We further showed that levels of antibodies to the domain of PfRh2 protein were similar to antibody levels of PfRh5, indicating it is less recognized by the immune system.
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Affiliation(s)
- Yaw Aniweh
- West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, P.O. Box LG54, Legon, Accra, Ghana. .,Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, P.O. Box LG54, Legon, Accra, Ghana.
| | - Jonathan Suurbaar
- West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, P.O. Box LG54, Legon, Accra, Ghana.,Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, P.O. Box LG54, Legon, Accra, Ghana
| | - Collins M Morang'a
- West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, P.O. Box LG54, Legon, Accra, Ghana.,Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, P.O. Box LG54, Legon, Accra, Ghana
| | - Prince B Nyarko
- West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, P.O. Box LG54, Legon, Accra, Ghana.,Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, P.O. Box LG54, Legon, Accra, Ghana
| | - Katherine E Wright
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK.,Department of Life Sciences, Imperial College London, London, UK
| | - Kwadwo A Kusi
- West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, P.O. Box LG54, Legon, Accra, Ghana.,Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, P.O. Box LG54, Legon, Accra, Ghana.,Immunology Department, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Felix Ansah
- West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, P.O. Box LG54, Legon, Accra, Ghana.,Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, P.O. Box LG54, Legon, Accra, Ghana
| | - Eric Kyei-Baafour
- Immunology Department, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Evelyn Quansah
- West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, P.O. Box LG54, Legon, Accra, Ghana.,Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, P.O. Box LG54, Legon, Accra, Ghana
| | - Jessica Asante
- Immunology Department, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Laty G Thiam
- West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, P.O. Box LG54, Legon, Accra, Ghana.,Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, P.O. Box LG54, Legon, Accra, Ghana
| | - Matthew K Higgins
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK
| | - Gordon A Awandare
- West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, P.O. Box LG54, Legon, Accra, Ghana. .,Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, P.O. Box LG54, Legon, Accra, Ghana.
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5
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Diédhiou CK, Moussa RA, Bei AK, Daniels R, Papa Mze N, Ndiaye D, Faye N, Wirth D, Amambua-Ngwa A, Mboup S, Ahouidi AD. Temporal changes in Plasmodium falciparum reticulocyte binding protein homolog 2b (PfRh2b) in Senegal and The Gambia. Malar J 2019; 18:239. [PMID: 31311552 PMCID: PMC6636118 DOI: 10.1186/s12936-019-2868-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Accepted: 07/05/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The Plasmodium falciparum reticulocyte binding protein homolog 2b (PfRh2b) is an important P. falciparum merozoite ligand that mediates invasion of erythrocytes by interacting with a chymotrypsin-sensitive "receptor Z". A large deletion polymorphism is found in the c-terminal ectodomain of this protein in many countries around the world, resulting in a truncated, but expressed protein. The varying frequencies by region suggest that there could be region specific immune selection at this locus. Therefore, this study was designed to determine temporal changes in the PfRh2b deletion polymorphism in infected individuals from Thiès (Senegal) and Western Gambia (The Gambia). It was also sought to determine the selective pressures acting at this locus and whether prevalence of the deletion in isolates genotyped by a 24-SNP molecular barcode is linked to background genotype or whether there might be independent selection acting at this locus. METHODS Infected blood samples were sourced from archives of previous studies conducted between 2007 and 2013 at SLAP clinic in Thiès and from 1984 to 2013 in Western Gambia by MRC Unit at LSHTM, The Gambia. A total of 1380 samples were screened for the dimorphic alleles of the PfRh2b using semi-nested Polymerase Chain Reaction PCR. Samples from Thiès were previously barcoded. RESULTS In Thiès, a consistent trend of decreasing prevalence of the PfRh2b deletion over time was observed: from 66.54% in 2007 and to 38.1% in 2013. In contrast, in Western Gambia, the frequency of the deletion fluctuated over time; it increased between 1984 and 2005 from (58.04%) to (69.33%) and decreased to 47.47% in 2007. Between 2007 and 2012, the prevalence of this deletion increased significantly from 47.47 to 83.02% and finally declined significantly to 57.94% in 2013. Association between the presence of this deletion and age was found in Thiès, however, not in Western Gambia. For the majority of isolates, the PfRh2b alleles could be tracked with specific 24-SNP barcoded genotype, indicating a lack of independent selection at this locus. CONCLUSION PfRh2b deletion was found in the two countries with varying prevalence during the study period. However, these temporal and spatial variations could be an obstacle to the implementation of this protein as a potential vaccine candidate.
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Affiliation(s)
- Cyrille K Diédhiou
- Institute for Health Research, Epidemiological Surveillance and Training (IRESSEF), Dakar, Senegal.,Laboratory of Bacteriology and Virology, Hospital Aristide Le Dantec, 7325, Dakar, Senegal
| | - Rahama A Moussa
- Laboratory of Bacteriology and Virology, Hospital Aristide Le Dantec, 7325, Dakar, Senegal
| | - Amy K Bei
- Laboratory of Bacteriology and Virology, Hospital Aristide Le Dantec, 7325, Dakar, Senegal.,Department of Immunology & Infectious Diseases, Harvard TH Chan School of Public Health, 665 Huntington Avenue, Boston, MA, USA.,Laboratory of Parasitology Mycology, Aristide Le Dantec Hospital, Faculty of Medicine and Pharmacy, Cheikh Anta Diop University, 5005, Dakar, Senegal
| | - Rachel Daniels
- Department of Immunology & Infectious Diseases, Harvard TH Chan School of Public Health, 665 Huntington Avenue, Boston, MA, USA
| | - Nasserdine Papa Mze
- Institute for Health Research, Epidemiological Surveillance and Training (IRESSEF), Dakar, Senegal.,Laboratory of Bacteriology and Virology, Hospital Aristide Le Dantec, 7325, Dakar, Senegal
| | - Daouda Ndiaye
- Laboratory of Parasitology Mycology, Aristide Le Dantec Hospital, Faculty of Medicine and Pharmacy, Cheikh Anta Diop University, 5005, Dakar, Senegal
| | - Ngor Faye
- Faculty of Sciences and Technologies, University Cheikh Anta Diop, Dakar, PO Box 5005, Dakar, Senegal
| | - Dyann Wirth
- Department of Immunology & Infectious Diseases, Harvard TH Chan School of Public Health, 665 Huntington Avenue, Boston, MA, USA
| | - Alfred Amambua-Ngwa
- Medical Research Council Unit, The Gambia at LSHTM, Fajara, Banjul, The Gambia
| | - Souleymane Mboup
- Institute for Health Research, Epidemiological Surveillance and Training (IRESSEF), Dakar, Senegal
| | - Ambroise D Ahouidi
- Institute for Health Research, Epidemiological Surveillance and Training (IRESSEF), Dakar, Senegal. .,Laboratory of Bacteriology and Virology, Hospital Aristide Le Dantec, 7325, Dakar, Senegal.
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6
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Ebrahimzadeh Z, Mukherjee A, Crochetière MÈ, Sergerie A, Amiar S, Thompson LA, Gagnon D, Gaumond D, Stahelin RV, Dacks JB, Richard D. A pan-apicomplexan phosphoinositide-binding protein acts in malarial microneme exocytosis. EMBO Rep 2019; 20:e47102. [PMID: 31097469 PMCID: PMC6549027 DOI: 10.15252/embr.201847102] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 03/28/2019] [Accepted: 04/12/2019] [Indexed: 11/09/2022] Open
Abstract
Invasion of human red blood cells by the malaria parasite Plasmodium falciparum is an essential step in the development of the disease. Consequently, the molecular players involved in host cell invasion represent important targets for inhibitor design and vaccine development. The process of merozoite invasion is a succession of steps underlined by the sequential secretion of the organelles of the apical complex. However, little is known with regard to how their contents are exocytosed. Here, we identify a phosphoinositide-binding protein conserved in apicomplexan parasites and show that it is important for the attachment and subsequent invasion of the erythrocyte by the merozoite. Critically, removing the protein from its site of action by knock sideways preferentially prevents the secretion of certain types of micronemes. Our results therefore provide evidence for a role of phosphoinositide lipids in the malaria invasion process and provide further insight into the secretion of microneme organelle populations, which is potentially applicable to diverse apicomplexan parasites.
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Affiliation(s)
- Zeinab Ebrahimzadeh
- Centre de Recherche en Infectiologie, CRCHU de Québec-Université Laval, Québec, QC, Canada
| | - Angana Mukherjee
- Centre de Recherche en Infectiologie, CRCHU de Québec-Université Laval, Québec, QC, Canada
| | - Marie-Ève Crochetière
- Centre de Recherche en Infectiologie, CRCHU de Québec-Université Laval, Québec, QC, Canada
| | - Audrey Sergerie
- Centre de Recherche en Infectiologie, CRCHU de Québec-Université Laval, Québec, QC, Canada
| | - Souad Amiar
- Department of Medicinal Chemistry and Molecular Pharmacology and the Purdue Institute of Inflammation, Immunology and Infectious Disease, Purdue University, West Lafayette, IN, USA
| | - L Alexa Thompson
- Division of Infectious Disease, Department of Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Dominic Gagnon
- Centre de Recherche en Infectiologie, CRCHU de Québec-Université Laval, Québec, QC, Canada
| | - David Gaumond
- Centre de Recherche en Infectiologie, CRCHU de Québec-Université Laval, Québec, QC, Canada
| | - Robert V Stahelin
- Department of Medicinal Chemistry and Molecular Pharmacology and the Purdue Institute of Inflammation, Immunology and Infectious Disease, Purdue University, West Lafayette, IN, USA
| | - Joel B Dacks
- Division of Infectious Disease, Department of Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Dave Richard
- Centre de Recherche en Infectiologie, CRCHU de Québec-Université Laval, Québec, QC, Canada
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Campino S, Marin-Menendez A, Kemp A, Cross N, Drought L, Otto TD, Benavente ED, Ravenhall M, Schwach F, Girling G, Manske M, Theron M, Gould K, Drury E, Clark TG, Kwiatkowski DP, Pance A, Rayner JC. A forward genetic screen reveals a primary role for Plasmodium falciparum Reticulocyte Binding Protein Homologue 2a and 2b in determining alternative erythrocyte invasion pathways. PLoS Pathog 2018; 14:e1007436. [PMID: 30496294 PMCID: PMC6289454 DOI: 10.1371/journal.ppat.1007436] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 12/11/2018] [Accepted: 10/24/2018] [Indexed: 12/14/2022] Open
Abstract
Invasion of human erythrocytes is essential for Plasmodium falciparum parasite survival and pathogenesis, and is also a complex phenotype. While some later steps in invasion appear to be invariant and essential, the earlier steps of recognition are controlled by a series of redundant, and only partially understood, receptor-ligand interactions. Reverse genetic analysis of laboratory adapted strains has identified multiple genes that when deleted can alter invasion, but how the relative contributions of each gene translate to the phenotypes of clinical isolates is far from clear. We used a forward genetic approach to identify genes responsible for variable erythrocyte invasion by phenotyping the parents and progeny of previously generated experimental genetic crosses. Linkage analysis using whole genome sequencing data revealed a single major locus was responsible for the majority of phenotypic variation in two invasion pathways. This locus contained the PfRh2a and PfRh2b genes, members of one of the major invasion ligand gene families, but not widely thought to play such a prominent role in specifying invasion phenotypes. Variation in invasion pathways was linked to significant differences in PfRh2a and PfRh2b expression between parasite lines, and their role in specifying alternative invasion was confirmed by CRISPR-Cas9-mediated genome editing. Expansion of the analysis to a large set of clinical P. falciparum isolates revealed common deletions, suggesting that variation at this locus is a major cause of invasion phenotypic variation in the endemic setting. This work has implications for blood-stage vaccine development and will help inform the design and location of future large-scale studies of invasion in clinical isolates. Plasmodium parasites cause more than 200 million cases of malaria each year. All the symptoms of malaria are caused after Plasmodium parasites invade human red blood cells. Once inside, they grow, multiply and break open the red blood cells to release new parasites. This cycle is repeated every 48 hours, rapidly amplifying the number of parasites and causing severe anemia and other complications. Plasmodium falciparum, the parasite species responsible for almost all malaria deaths, can use multiple different pathways to invade human red blood cells, but the relative importance of each is not well understood. We tested the invasion pathways used by a collection of closely related parasites and compared their genome sequences to identify the genes responsible. This analysis revealed that expression differences in two neighboring genes of the Reticulocyte Binding Homologue family are responsible for most of the variation in two invasion pathways. P. falciparum may use variation in these genes to avoid the immune system or adapt to specific blood groups, which has important implications for vaccine development against malaria.
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Affiliation(s)
- Susana Campino
- Malaria Programme, Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, United Kingdom
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
- * E-mail: (SC); (JCR)
| | - Alejandro Marin-Menendez
- Malaria Programme, Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Alison Kemp
- Malaria Programme, Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Nadia Cross
- Malaria Programme, Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Laura Drought
- Malaria Programme, Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Thomas D. Otto
- Malaria Programme, Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, United Kingdom
- Centre of Immunobiology, Institute of Infection, Immunity & Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Ernest Diez Benavente
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Matt Ravenhall
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Frank Schwach
- Malaria Programme, Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Gareth Girling
- Malaria Programme, Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Magnus Manske
- Malaria Programme, Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Michel Theron
- Malaria Programme, Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Kelda Gould
- Malaria Programme, Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Eleanor Drury
- Malaria Programme, Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Taane G. Clark
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Dominic P. Kwiatkowski
- Malaria Programme, Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, United Kingdom
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Alena Pance
- Malaria Programme, Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Julian C. Rayner
- Malaria Programme, Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, United Kingdom
- * E-mail: (SC); (JCR)
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8
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Pandey R, Kumar R, Gupta P, Mohmmed A, Tewari R, Malhotra P, Gupta D. High throughput in silico identification and characterization of Plasmodium falciparum PRL phosphatase inhibitors. J Biomol Struct Dyn 2017; 36:3531-3540. [PMID: 29039247 DOI: 10.1080/07391102.2017.1392365] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Kinases and phosphatases are involved in many essential processes in Plasmodium lifecycle. Among the identified 67 Plasmodium falciparum phosphatases, Phosphatase of Regenerating Liver (PRL) family protein homolog, PfPRL, is an essential parasite tyrosine phosphatase. PfPRL is shown to be prenylated, secreted, and involved in the host invasion process. In the present study, a structure-based high throughput in silico screening of PfPRL binders, using ChEMBL-NTD compounds lead to the identification of nine compounds based on binding energy, Lipinski rule of five, and QED score. The most of the shortlisted compounds are known to inhibit parasite growth at a concentration (EC50) ≤2 μm in in vitro P. falciparum culture assays. MD simulations were carried out on the shortlisted nine potential enzyme-inhibitor complexes to analyze specificity, stability, and to calculate the free binding energies of the complexes. The study identifies PfPRL as one of the potential drug targets for selected ChEMBL-NTD compounds that may be exploited as a scaffold to develop novel antimalarials.
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Affiliation(s)
- Rajan Pandey
- a Translational Bioinformatics Group , International Centre for Genetic Engineering and Biotechnology , Aruna Asaf Ali Marg, New Delhi - 110067 , India
| | - Rakesh Kumar
- a Translational Bioinformatics Group , International Centre for Genetic Engineering and Biotechnology , Aruna Asaf Ali Marg, New Delhi - 110067 , India
| | - Priya Gupta
- b Malaria Biology Group , International Centre for Genetic Engineering and Biotechnology , Aruna Asaf Ali Marg, New Delhi - 110067 , India
| | - Asif Mohmmed
- c Parasite Cell Biology Group , International Centre for Genetic Engineering and Biotechnology , Aruna Asaf Ali Marg, New Delhi - 110067 , India
| | - Rita Tewari
- d Centre for Genetics and Genomics, School of Life Sciences , Queens Medical Centre, University of Nottingham , Nottingham NG2 7UH , UK
| | - Pawan Malhotra
- b Malaria Biology Group , International Centre for Genetic Engineering and Biotechnology , Aruna Asaf Ali Marg, New Delhi - 110067 , India
| | - Dinesh Gupta
- a Translational Bioinformatics Group , International Centre for Genetic Engineering and Biotechnology , Aruna Asaf Ali Marg, New Delhi - 110067 , India
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9
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PfCDPK1 mediated signaling in erythrocytic stages of Plasmodium falciparum. Nat Commun 2017; 8:63. [PMID: 28680058 PMCID: PMC5498596 DOI: 10.1038/s41467-017-00053-1] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Accepted: 04/26/2017] [Indexed: 01/11/2023] Open
Abstract
Calcium Dependent Protein Kinases are key effectors of calcium signaling in malaria parasite. PfCDPK1 is critical for asexual development of Plasmodium falciparum, but its precise function and substrates remain largely unknown. Using a conditional knockdown strategy, we here establish that this kinase is critical for the invasion of host erythrocytes. Furthermore, using a multidisciplinary approach involving comparative phosphoproteomics we gain insights into the underlying molecular mechanisms. We identify substrates of PfCDPK1, which includes proteins of Inner Membrane Complex and glideosome-actomyosin motor assembly. Interestingly, PfCDPK1 phosphorylates PfPKA regulatory subunit (PfPKA-R) and regulates PfPKA activity in the parasite, which may be relevant for the process of invasion. This study delineates the signaling network of PfCDPK1 and sheds light on mechanisms via which it regulates invasion.Calcium dependent protein kinase 1 (CDPK1) plays an important role in asexual development of Plasmodium falciparum. Using phosphoproteomics and conditional knockdown of CDPK1, the authors here identify CDPK1 substrates and a cross-talk between CDPK1 and PKA, and show the role of CDPK1 in parasite invasion.
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Diaz SA, Martin SR, Howell SA, Grainger M, Moon RW, Green JL, Holder AA. The Binding of Plasmodium falciparum Adhesins and Erythrocyte Invasion Proteins to Aldolase Is Enhanced by Phosphorylation. PLoS One 2016; 11:e0161850. [PMID: 27607074 PMCID: PMC5015959 DOI: 10.1371/journal.pone.0161850] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Accepted: 08/14/2016] [Indexed: 02/07/2023] Open
Abstract
Aldolase has been implicated as a protein coupling the actomyosin motor and cell surface adhesins involved in motility and host cell invasion in the human malaria parasite Plasmodium falciparum. It binds to the cytoplasmic domain (CTD) of type 1 membrane proteins of the thrombospondin-related anonymous protein (TRAP) family. Other type 1 membrane proteins located in the apical organelles of merozoites, the form of the parasite that invades red blood cells, including apical membrane antigen 1 (AMA1) and members of the erythrocyte binding ligand (EBL) and reticulocyte binding homologue (RH) protein families have been implicated in host cell binding and invasion. Using a direct binding method we confirm that TRAP and merozoite TRAP (MTRAP) bind aldolase and show that the interaction is mediated by more than just the C-terminal six amino acid residues identified previously. Single amino acid substitutions in the MTRAP CTD abolished binding to aldolase. The CTDs of AMA1 and members of the EBL and RH protein families also bound to aldolase. MTRAP competed with AMA1 and RH4 for binding to aldolase, indicating overlapping binding sites. MTRAP CTD was phosphorylated in vitro by both calcium dependent kinase 1 (CDPK1) and protein kinase A, and this modification increased the affinity of binding to aldolase by ten-fold. Phosphorylation of the CTD of members of the EBL and RH protein families also increased their affinity for aldolase in some cases. To examine whether or not MTRAP expressed in asexual blood stage parasites is phosphorylated, it was tagged with GFP, purified and analysed, however no phosphorylation was detected. We propose that CTD binding to aldolase may be dynamically modulated by phosphorylation, and there may be competition for aldolase binding between different CTDs. The use and efficiency of alternate invasion pathways may be determined by the affinity of adhesins and cell invasion proteins for aldolase, in addition to their host ligand specificity.
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Affiliation(s)
- Suraya A. Diaz
- Malaria Parasitology Laboratory, The Francis Crick Institute, Mill Hill Laboratory, The Ridgeway, Mill Hill, London, NW7 1AA, United Kingdom
| | - Stephen R. Martin
- Structural Biology Science Technology Platform The Francis Crick Institute, Mill Hill Laboratory, The Ridgeway, Mill Hill, London, NW7 1AA, United Kingdom
| | - Steven A. Howell
- Mass Spectrometry Science Technology Platform, The Francis Crick Institute, Mill Hill Laboratory, The Ridgeway, Mill Hill, London, NW7 1AA, United Kingdom
| | - Munira Grainger
- Malaria Parasitology Laboratory, The Francis Crick Institute, Mill Hill Laboratory, The Ridgeway, Mill Hill, London, NW7 1AA, United Kingdom
| | - Robert W. Moon
- Malaria Parasitology Laboratory, The Francis Crick Institute, Mill Hill Laboratory, The Ridgeway, Mill Hill, London, NW7 1AA, United Kingdom
| | - Judith L. Green
- Malaria Parasitology Laboratory, The Francis Crick Institute, Mill Hill Laboratory, The Ridgeway, Mill Hill, London, NW7 1AA, United Kingdom
| | - Anthony A. Holder
- Malaria Parasitology Laboratory, The Francis Crick Institute, Mill Hill Laboratory, The Ridgeway, Mill Hill, London, NW7 1AA, United Kingdom
- * E-mail:
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11
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Aniweh Y, Gao X, Gunalan K, Preiser PR. PfRH2b specific monoclonal antibodies inhibit merozoite invasion. Mol Microbiol 2016; 102:386-404. [DOI: 10.1111/mmi.13468] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/18/2016] [Indexed: 11/28/2022]
Affiliation(s)
- Yaw Aniweh
- Division of Molecular Genetics and Cell biology, School of Biological Sciences; Nanyang Technological University; 637551 Singapore
| | - Xiaohong Gao
- Division of Molecular Genetics and Cell biology, School of Biological Sciences; Nanyang Technological University; 637551 Singapore
| | - Karthigayan Gunalan
- Division of Molecular Genetics and Cell biology, School of Biological Sciences; Nanyang Technological University; 637551 Singapore
| | - Peter R. Preiser
- Division of Molecular Genetics and Cell biology, School of Biological Sciences; Nanyang Technological University; 637551 Singapore
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Ord RL, Rodriguez M, Lobo CA. Malaria invasion ligand RH5 and its prime candidacy in blood-stage malaria vaccine design. Hum Vaccin Immunother 2016; 11:1465-73. [PMID: 25844685 DOI: 10.1080/21645515.2015.1026496] [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] [Indexed: 12/26/2022] Open
Abstract
With drug resistance to available therapeutics continuing to develop against Plasmodium falciparum malaria, the development of an effective vaccine candidate remains a major research goal. Successful interruption of invasion of parasites into erythrocytes during the blood stage of infection will prevent the severe clinical symptoms and complications associated with malaria. Previously studied blood stage antigens have highlighted the hurdles that are inherent to this life-cycle stage, namely that highly immunogenic antigens are also globally diverse, resulting in protection only against the vaccine strain, or that naturally acquired immunity to blood stage antigens do not always correlate with actual protection. The blood stage antigen reticulocyte binding homolog RH5 is essential for parasite viability, has globally limited diversity, and is associated with protection from disease. Here we summarize available information on this invasion ligand and recent findings that highlight its candidacy for inclusion in a blood-stage malaria vaccine.
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Affiliation(s)
- Rosalynn L Ord
- a Blood-Borne Parasites; Lindsley Kimball Research Institute; New York Blood Center ; New York , NY , USA
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Beeson JG, Drew DR, Boyle MJ, Feng G, Fowkes FJI, Richards JS. Merozoite surface proteins in red blood cell invasion, immunity and vaccines against malaria. FEMS Microbiol Rev 2016; 40:343-72. [PMID: 26833236 PMCID: PMC4852283 DOI: 10.1093/femsre/fuw001] [Citation(s) in RCA: 228] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/03/2016] [Indexed: 01/11/2023] Open
Abstract
Malaria accounts for an enormous burden of disease globally, with Plasmodium falciparum accounting for the majority of malaria, and P. vivax being a second important cause, especially in Asia, the Americas and the Pacific. During infection with Plasmodium spp., the merozoite form of the parasite invades red blood cells and replicates inside them. It is during the blood-stage of infection that malaria disease occurs and, therefore, understanding merozoite invasion, host immune responses to merozoite surface antigens, and targeting merozoite surface proteins and invasion ligands by novel vaccines and therapeutics have been important areas of research. Merozoite invasion involves multiple interactions and events, and substantial processing of merozoite surface proteins occurs before, during and after invasion. The merozoite surface is highly complex, presenting a multitude of antigens to the immune system. This complexity has proved challenging to our efforts to understand merozoite invasion and malaria immunity, and to developing merozoite antigens as malaria vaccines. In recent years, there has been major progress in this field, and several merozoite surface proteins show strong potential as malaria vaccines. Our current knowledge on this topic is reviewed, highlighting recent advances and research priorities. The authors summarize current knowledge of merozoite surface proteins of malaria parasites; their function in invasion, processing of surface proteins before, during and after invasion, their importance as targets of immunity, and the current status of malaria vaccines that target merozoite surface proteins.
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Affiliation(s)
- James G Beeson
- Burnet Institute for Medical Research and Public Health, 85 Commercial Road, Melbourne, Victoria, Australia Department of Microbiology, Monash University, Clayton, Victoria, Australia Department of Medicine, University of Melbourne, Parkville, Victoria, Australia
| | - Damien R Drew
- Burnet Institute for Medical Research and Public Health, 85 Commercial Road, Melbourne, Victoria, Australia
| | - Michelle J Boyle
- Burnet Institute for Medical Research and Public Health, 85 Commercial Road, Melbourne, Victoria, Australia
| | - Gaoqian Feng
- Burnet Institute for Medical Research and Public Health, 85 Commercial Road, Melbourne, Victoria, Australia
| | - Freya J I Fowkes
- Burnet Institute for Medical Research and Public Health, 85 Commercial Road, Melbourne, Victoria, Australia Department of Epidemiology and Preventive Medicine, Monash University, Clayton, Victoria, Australia School of Population Health, University of Melbourne, Parkville, Victoria, Australia
| | - Jack S Richards
- Burnet Institute for Medical Research and Public Health, 85 Commercial Road, Melbourne, Victoria, Australia Department of Microbiology, Monash University, Clayton, Victoria, Australia Department of Medicine, University of Melbourne, Parkville, Victoria, Australia
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Tham WH, Lim NTY, Weiss GE, Lopaticki S, Ansell BRE, Bird M, Lucet I, Dorin-Semblat D, Doerig C, Gilson PR, Crabb BS, Cowman AF. Plasmodium falciparum Adhesins Play an Essential Role in Signalling and Activation of Invasion into Human Erythrocytes. PLoS Pathog 2015; 11:e1005343. [PMID: 26694741 PMCID: PMC4687929 DOI: 10.1371/journal.ppat.1005343] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Accepted: 11/24/2015] [Indexed: 11/19/2022] Open
Abstract
The most severe form of malaria in humans is caused by the protozoan parasite Plasmodium falciparum. The invasive form of malaria parasites is termed a merozoite and it employs an array of parasite proteins that bind to the host cell to mediate invasion. In Plasmodium falciparum, the erythrocyte binding-like (EBL) and reticulocyte binding-like (Rh) protein families are responsible for binding to specific erythrocyte receptors for invasion and mediating signalling events that initiate active entry of the malaria parasite. Here we have addressed the role of the cytoplasmic tails of these proteins in activating merozoite invasion after receptor engagement. We show that the cytoplasmic domains of these type 1 membrane proteins are phosphorylated in vitro. Depletion of PfCK2, a kinase implicated to phosphorylate these cytoplasmic tails, blocks P. falciparum invasion of red blood cells. We identify the crucial residues within the PfRh4 cytoplasmic domain that are required for successful parasite invasion. Live cell imaging of merozoites from these transgenic mutants show they attach but do not penetrate erythrocytes implying the PfRh4 cytoplasmic tail conveys signals important for the successful completion of the invasion process.
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Affiliation(s)
- Wai-Hong Tham
- The Walter & Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia
| | - Nicholas T. Y. Lim
- The Walter & Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia
| | | | - Sash Lopaticki
- The Walter & Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia
| | - Brendan R. E. Ansell
- The Walter & Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia
| | - Megan Bird
- Department of Microbiology, Monash University, Melbourne, Victoria, Australia
| | - Isabelle Lucet
- The Walter & Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia
- Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Monash University, Clayton, Victoria, Australia
| | | | - Christian Doerig
- Department of Microbiology, Monash University, Melbourne, Victoria, Australia
| | - Paul R. Gilson
- Burnet Institute, Melbourne, Victoria, Australia
- Department of Immunology, Monash University, Melbourne, Victoria, Australia
| | - Brendan S. Crabb
- Burnet Institute, Melbourne, Victoria, Australia
- Department of Immunology, Monash University, Melbourne, Victoria, Australia
- Department of Microbiology & Immunology, The University of Melbourne, Parkville, Victoria, Australia
| | - Alan F. Cowman
- The Walter & Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia
- * E-mail:
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Paul AS, Saha S, Engelberg K, Jiang RHY, Coleman BI, Kosber AL, Chen CT, Ganter M, Espy N, Gilberger TW, Gubbels MJ, Duraisingh MT. Parasite Calcineurin Regulates Host Cell Recognition and Attachment by Apicomplexans. Cell Host Microbe 2015; 18:49-60. [PMID: 26118996 DOI: 10.1016/j.chom.2015.06.003] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Revised: 04/30/2015] [Accepted: 05/28/2015] [Indexed: 12/12/2022]
Abstract
Apicomplexans invade a variety of metazoan host cells through mechanisms involving host cell receptor engagement and secretion of parasite factors to facilitate cellular attachment. We find that the parasite homolog of calcineurin, a calcium-regulated phosphatase complex central to signal transduction in eukaryotes, also contributes to host cell invasion by the malaria parasite Plasmodium falciparum and related Toxoplasma gondii. Using reverse-genetic and chemical-genetic approaches, we determine that calcineurin critically regulates and stabilizes attachment of extracellular P. falciparum to host erythrocytes before intracellular entry and has similar functions in host cell engagement by T. gondii. Calcineurin-mediated Plasmodium invasion is strongly associated with host receptors required for host cell recognition, and calcineurin function distinguishes this form of receptor-mediated attachment from a second mode of host-parasite adhesion independent of host receptors. This specific role of calcineurin in coordinating physical interactions with host cells highlights an ancestral mechanism for parasitism used by apicomplexans.
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Affiliation(s)
- Aditya S Paul
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
| | - Sudeshna Saha
- Department of Biology, Boston College, Chestnut Hill, MA 02467, USA
| | | | - Rays H Y Jiang
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
| | | | - Aziz L Kosber
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
| | - Chun-Ti Chen
- Department of Biology, Boston College, Chestnut Hill, MA 02467, USA
| | - Markus Ganter
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
| | - Nicole Espy
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
| | - Tim W Gilberger
- Bernhard Nocht Institute for Tropical Medicine, 20359 Hamburg, Germany; Centre for Structural Systems Biology, 22607 Hamburg, Germany
| | - Marc-Jan Gubbels
- Department of Biology, Boston College, Chestnut Hill, MA 02467, USA
| | - Manoj T Duraisingh
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA.
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Sennang N, Rogerson S, Wahyuni S, Yusuf I, Syafruddin D. Antibody response against three Plasmodium falciparum merozoite antigens in Mamuju District, West Sulawesi Province, Indonesia. Malar J 2014; 13:381. [PMID: 25255775 PMCID: PMC4193137 DOI: 10.1186/1475-2875-13-381] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Accepted: 09/18/2014] [Indexed: 11/18/2022] Open
Abstract
Background Malaria endemicity in the archipelago of Indonesia varies substantially across regions. Following the government’s plan for a malaria elimination programme in Indonesia, baseline malaria surveys were conducted in Mamuju District, West Sulawesi Province, Indonesia to re-assess the malaria situation prior to the establishment of an evidence-based malaria elimination programme in the area. The present study aims to determine the antibody response to three merozoite antigens among the inhabitants of the district. Methods Antibodies were measured following elution from filter-paper blood spots collected during cross-sectional surveys in the dry and wet season in 2010. Enzyme-linked immunosorbent assays using three merozoite antigens, MSP2, EBA175 and PfRh2a were conducted. A positivity threshold was determined by samples from unexposed individuals and the difference in antibody level against each antigen and correlation of antibody level in different age groups and seasons were statistically analysed. Results A total of 497 subjects, 248 in dry and 249 in wet season, aged between 0.6 and 78 years were included. The prevalence of positive antibody responses to MSP2, EBA175 and PfRh2a antigens in dry season were 27.82, 27.42 and 25.81%, respectively. In wet season, the antibody prevalences were 64.26, 64.66 and 61.45%. The antibody levels to the three antigens were all higher in older age groups and also significantly higher in the wet season. The antibody levels also correlated positively with the Plasmodium falciparum infection status of the subjects. Conclusion MSP2, EBA175 and PfRh2a induce antibody responses among the subjects in Mamuju District, and the prevalence is significantly higher in wet season. The level of antibody also correlates significantly with age and malaria positivity. The overall results indicate the antigens might be used as a target for vaccines against P. falciparum infection and as markers for malaria exposure.
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Affiliation(s)
| | | | | | | | - Din Syafruddin
- Department of Parasitology, Faculty of Medicine, Hasanuddin University, Makassar 90245, South Sulawesi, Indonesia.
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Otto TD, Rayner JC, Böhme U, Pain A, Spottiswoode N, Sanders M, Quail M, Ollomo B, Renaud F, Thomas AW, Prugnolle F, Conway DJ, Newbold C, Berriman M. Genome sequencing of chimpanzee malaria parasites reveals possible pathways of adaptation to human hosts. Nat Commun 2014; 5:4754. [PMID: 25203297 PMCID: PMC4166903 DOI: 10.1038/ncomms5754] [Citation(s) in RCA: 114] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Accepted: 07/18/2014] [Indexed: 01/19/2023] Open
Abstract
Plasmodium falciparum causes most human malaria deaths, having prehistorically evolved from parasites of African Great Apes. Here we explore the genomic basis of P. falciparum adaptation to human hosts by fully sequencing the genome of the closely related chimpanzee parasite species P. reichenowi, and obtaining partial sequence data from a more distantly related chimpanzee parasite (P. gaboni). The close relationship between P. reichenowi and P. falciparum is emphasized by almost complete conservation of genomic synteny, but against this strikingly conserved background we observe major differences at loci involved in erythrocyte invasion. The organization of most virulence-associated multigene families, including the hypervariable var genes, is broadly conserved, but P. falciparum has a smaller subset of rif and stevor genes whose products are expressed on the infected erythrocyte surface. Genome-wide analysis identifies other loci under recent positive selection, but a limited number of changes at the host-parasite interface may have mediated host switching.
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Affiliation(s)
- Thomas D. Otto
- Parasite Genomics, Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Cambridge CB10 1SA, UK
| | - Julian C. Rayner
- Parasite Genomics, Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Cambridge CB10 1SA, UK
| | - Ulrike Böhme
- Parasite Genomics, Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Cambridge CB10 1SA, UK
| | - Arnab Pain
- Parasite Genomics, Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Cambridge CB10 1SA, UK
- Biological and Environmental Sciences and Engineering (BESE) Division, Computational Bioscience Research Center, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia
| | - Natasha Spottiswoode
- National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland 20852, USA
- Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, UK
| | - Mandy Sanders
- Parasite Genomics, Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Cambridge CB10 1SA, UK
| | - Michael Quail
- Parasite Genomics, Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Cambridge CB10 1SA, UK
| | - Benjamin Ollomo
- Centre International de Recherches Médicales de Franceville, CIRMF, BP 769 Franceville, Gabon
| | - François Renaud
- Laboratoire MIVEGEC, UMR 5290 CNRS-IRD-UMI-UMII, IRD, BP 64501, 34394 Montpellier, France
| | - Alan W. Thomas
- Biomedical Primate Research Centre, Department of Parasitology, 2280 GH Rijswijk, The Netherlands
| | - Franck Prugnolle
- Centre International de Recherches Médicales de Franceville, CIRMF, BP 769 Franceville, Gabon
- Laboratoire MIVEGEC, UMR 5290 CNRS-IRD-UMI-UMII, IRD, BP 64501, 34394 Montpellier, France
| | - David J. Conway
- Department of Pathogen Molecular Biology, London School of Hygiene & Tropical Medicine, London WC1E 7HT, UK
| | - Chris Newbold
- Parasite Genomics, Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Cambridge CB10 1SA, UK
- Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, UK
- These authors contributed equally to this work
| | - Matthew Berriman
- Parasite Genomics, Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Cambridge CB10 1SA, UK
- These authors contributed equally to this work
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Advantages and disadvantages of conditional systems for characterization of essential genes in Toxoplasma gondii. Parasitology 2014; 141:1390-8. [PMID: 24926834 DOI: 10.1017/s0031182014000559] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The dissection of apicomplexan biology has been highly influenced by the genetic tools available for manipulation of parasite DNA. Here, we describe different techniques available for the generation of conditional mutants. Comparison of the advantages and disadvantages of the three most commonly used regulation systems: the tetracycline inducible system, the regulation of protein stability and site-specific recombination are discussed. Using some previously described examples we explore some of the pitfalls involved in gene-function analysis using these systems that can lead to wrong or over-interpretation of phenotypes. We will also mention different options to standardize the application of these techniques for the characterization of gene function in high-throughput.
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Abstract
Invasion into red blood cells is an essential step in the life cycle of parasites that cause human malaria. Antibodies targeting the key parasite proteins in this process are important for developing a protective immune response. In the current issue, Boyle and colleagues provide a detailed examination of Plasmodium falciparum invasion and specifically illuminate the fate of surface-exposed parasite proteins during and immediately after invasion.
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Abstract
Red blood cell invasion by the malaria parasite Plasmodium falciparum relies on a complex protein network that uses low and high affinity receptor–ligand interactions. Signal transduction through the action of specific kinases is a control mechanism for the orchestration of this process. In the present study we report on the phosphorylation of the CPD (cytoplasmic domain) of P. falciparum Rh2b (reticulocyte homologue protein 2b). First, we identified Ser3233 as the sole phospho-acceptor site in the CPD for in vitro phosphorylation by parasite extract. We provide several lines of evidence that this phosphorylation is mediated by PfCK2 (P. falciparum casein kinase 2): phosphorylation is cAMP independent, utilizes ATP as well as GTP as phosphate donors, is inhibited by heparin and tetrabromocinnamic acid, and is mediated by purified PfCK2. We raised a phospho-specific antibody and showed that Ser3233 phosphorylation occurs in the parasite prior to host cell egress. We analysed the spatiotemporal aspects of this phosphorylation using immunoprecipitated endogenous Rh2b and minigenes expressing the CPD either at the plasma or rhoptry membrane. Phosphorylation of Rh2b is not spatially restricted to either the plasma or rhoptry membrane and most probably occurs before Rh2b is translocated from the rhoptry neck to the plasma membrane.
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Patel SD, Ahouidi AD, Bei AK, Dieye TN, Mboup S, Harrison SC, Duraisingh MT. Plasmodium falciparum merozoite surface antigen, PfRH5, elicits detectable levels of invasion-inhibiting antibodies in humans. J Infect Dis 2013; 208:1679-87. [PMID: 23904294 DOI: 10.1093/infdis/jit385] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Plasmodium falciparum is an intracellular protozoan parasite that infects erythrocytes and hepatocytes. The blood stage of its life cycle causes substantial morbidity and mortality associated with millions of infections each year, motivating an intensive search for potential components of a multi-subunit vaccine. In this study, we present data showing that antibodies from natural infections can recognize a recombinant form of the relatively conserved merozoite surface antigen, PfRH5. Furthermore, we performed invasion inhibition assays on clinical isolates and laboratory strains of P. falciparum in the presence of affinity purified antibodies to RH5 and show that these antibodies can inhibit invasion in vitro.
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Jain S, Rathore S, Asad M, Hossain ME, Sinha D, Datta G, Mohmmed A. The prokaryotic ClpQ protease plays a key role in growth and development of mitochondria in Plasmodium falciparum. Cell Microbiol 2013; 15:1660-73. [PMID: 23521916 DOI: 10.1111/cmi.12142] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2012] [Revised: 02/18/2013] [Accepted: 03/14/2013] [Indexed: 01/17/2023]
Abstract
The ATP-dependent ClpQY system is a prokaryotic proteasome-like multi-subunit machinery localized in the mitochondrion of malaria parasite. The ClpQY machinery consists of ClpQ threonine protease and ClpY ATPase. In the present study, we have assessed cellular effects of transient interference of PfClpQ protease activity in Plasmodium falciparum using a trans-dominant negative approach combined with FKBP degradation domain system. A proteolytically inactive mutant PfClpQ protein [PfClpQ(mut)] fused with FKBP degradation domain was expressed in parasites, which gets stabilized by Shield1 drug treatment. We show that the inactive PfClpQ(mut) interacts with wild-type PfClpQ and associates within multi-subunit complex in the parasite. Stabilization of the PfClpQ(mut) and its association in the protease machinery caused dominant negative effect in the transgenic parasites, which disrupted the growth cycle of asexual blood stage parasites. The mitochondria in these parasites showed abnormal morphology, these mitochondria were not able to grow and divide in the parasite. We further show that the dominant negative effect of PfClpQ(mut) disrupted transcription of mitochondrial genome encoded genes, which in turn blocked normal development and functioning of the mitochondria.
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Affiliation(s)
- Shaifali Jain
- International Centre for Genetic Engineering and Biotechnology, New Delhi, 110 067, India
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Yu FD, Yang SY, Li YY, Hu W. Co-expression network with protein–protein interaction and transcription regulation in malaria parasite Plasmodium falciparum. Gene 2013; 518:7-16. [DOI: 10.1016/j.gene.2012.11.092] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Accepted: 11/27/2012] [Indexed: 12/16/2022]
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Gunalan K, Gao X, Yap SSL, Huang X, Preiser PR. The role of the reticulocyte-binding-like protein homologues of Plasmodium in erythrocyte sensing and invasion. Cell Microbiol 2012; 15:35-44. [PMID: 23046317 DOI: 10.1111/cmi.12038] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2012] [Revised: 09/17/2012] [Accepted: 10/01/2012] [Indexed: 11/27/2022]
Abstract
Malaria remains a serious public health problem with significant morbidity and mortality accounting for nearly 20% of all childhood deaths in Africa. The cyclical invasion, cytoadherence and destruction of the host's erythrocyte by the parasite are responsible for the observed disease pathology. The invasive form of the parasite, the merozoite, uses a complex set of interactions between parasite ligands and erythrocyte receptors that leads to the formation of a tight junction and ultimately successful erythrocyte invasion. Understanding the molecular mechanism underlying host cell recognition and invasion is crucial for the development of a targeted intervention strategy. Two parasite protein families termed reticulocyte-binding-like protein homologues (RBL) and the erythrocyte-binding-like (EBL) protein family are conserved in all Plasmodium species and have been shown to play an important role in host cell recognition and invasion. Over the last few years significant new insights have been gained in understanding the function of the RBL family and this review attempts to provide an update with a specific focus on the role of RBL in signal transduction pathways during invasion.
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Affiliation(s)
- Karthigayan Gunalan
- Division of Molecular Genetics & Cell Biology, School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
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25
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Binding of aldolase and glyceraldehyde-3-phosphate dehydrogenase to the cytoplasmic tails of Plasmodium falciparum merozoite duffy binding-like and reticulocyte homology ligands. mBio 2012; 3:mBio.00292-12. [PMID: 22991428 PMCID: PMC3448169 DOI: 10.1128/mbio.00292-12] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Invasion of erythrocytes by Plasmodium falciparum requires a connection between the cytoplasmic tail of the parasite’s ligands for its erythrocyte receptors and the actin-myosin motor of the parasite. For the thromobospondin-related anonymous protein (TRAP) ligand on Plasmodium sporozoites, aldolase forms this connection and requires tryptophan and negatively charged amino acids in the ligand’s cytoplasmic tail. Because of the importance of the Duffy binding-like (DBL) and the reticulocyte homology (RH) ligand families in erythrocyte binding and merozoite invasion, we characterized the ability of their cytoplasmic tails to bind aldolase and glyceraldehyde-3-phosphate dehydrogenase (GAPDH), both of which bind actin. We tested the binding of the cytoplasmic peptides of the two ligand families to aldolase and GAPDH. Only the cytoplasmic peptides of some RH ligands showed strong binding to aldolase, and the binding depended on the presence of an aromatic amino acid (phenylalanine or tyrosine), rather than tryptophan, in the context of negatively charged amino acids. The binding was confirmed by surface plasmon resonance analysis and was found to represent affinity similar to that seen with TRAP. An X-ray crystal structure of aldolase at 2.5 Å in the presence of RH2b peptide suggested that the binding site location was near the TRAP-binding site. GAPDH bound to some of the cytoplasmic tails of certain RH and DBL ligands in an aromatic amino acid-dependent manner. Thus, the connection between Plasmodium merozoite ligands and erythrocyte receptors and the actin motor can be achieved through the activity of either aldolase or GAPDH by mechanisms that do not require tryptophan but, rather, other aromatic amino acids. The invasion of the Plasmodium merozoite into erythrocytes is a critical element in malaria pathogenesis. It is important to understand the molecular details of this process, as this machinery can be a target for both vaccine and drug development. In Plasmodium sporozoites and Toxoplasma tachyzoites, invasion involves a glycolytic enzyme aldolase, linking the cytoplasmic tail domains of the parasite ligands to the actin-myosin motor that drives invasion. This binding requires a tryptophan that cannot be replaced by other aromatic residues. Here we show that aldolase binds the cytoplasmic tails of some P. falciparum merozoite erythrocyte-binding ligands but that the binding involves aromatic residues other than tryptophan. The biological relevance of aldolase binding to cytoplasmic tails of parasite ligands in invasion is demonstrated by our observation that RH2b but not RH2a binds to aldolase and, as previously shown, that RH2b but not RH2a is required for P. falciparum invasion of erythrocytes.
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Li J, Han ET. Dissection of the Plasmodium vivax reticulocyte binding-like proteins (PvRBPs). Biochem Biophys Res Commun 2012; 426:1-6. [DOI: 10.1016/j.bbrc.2012.08.055] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Accepted: 08/11/2012] [Indexed: 01/08/2023]
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Harvey KL, Gilson PR, Crabb BS. A model for the progression of receptor-ligand interactions during erythrocyte invasion by Plasmodium falciparum. Int J Parasitol 2012; 42:567-73. [PMID: 22710063 DOI: 10.1016/j.ijpara.2012.02.011] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2011] [Revised: 02/18/2012] [Accepted: 02/23/2012] [Indexed: 11/17/2022]
Abstract
Multiple and seemingly sequential interactions between parasite ligands and their receptors on host erythrocytes are an essential precursor to invasion by the obligate intracellular pathogen, Plasmodium falciparum. Consequently, identification and characterisation of the specific effectors that facilitate these recognition events are of special interest for the development of novel therapeutic and prophylactic solutions to malaria. There have been many recent advances regarding the identification of host-parasite receptor-ligand pairs, however the precise function and temporal aspects of these interactions are far from resolved. This review provides an update on the current details of these interactions to place them in sequence and super impose them upon the known kinetic events of invasion.
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28
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Farrell A, Thirugnanam S, Lorestani A, Dvorin JD, Eidell KP, Ferguson DJ, Anderson-White BR, Duraisingh MT, Marth GT, Gubbels MJ. A DOC2 protein identified by mutational profiling is essential for apicomplexan parasite exocytosis. Science 2012; 335:218-21. [PMID: 22246776 PMCID: PMC3354045 DOI: 10.1126/science.1210829] [Citation(s) in RCA: 100] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Exocytosis is essential to the lytic cycle of apicomplexan parasites and required for the pathogenesis of toxoplasmosis and malaria. DOC2 proteins recruit the membrane fusion machinery required for exocytosis in a Ca(2+)-dependent fashion. Here, the phenotype of a Toxoplasma gondii conditional mutant impaired in host cell invasion and egress was pinpointed to a defect in secretion of the micronemes, an apicomplexan-specific organelle that contains adhesion proteins. Whole-genome sequencing identified the etiological point mutation in TgDOC2.1. A conditional allele of the orthologous gene engineered into Plasmodium falciparum was also defective in microneme secretion. However, the major effect was on invasion, suggesting that microneme secretion is dispensable for Plasmodium egress.
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Affiliation(s)
- Andrew Farrell
- Department of Biology, Boston College, Chestnut Hill, MA 02467, USA
| | | | | | - Jeffrey D. Dvorin
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, MA 02115, USA
- Division of Infectious Diseases, Children’s Hospital Boston, Boston, MA 02115, USA
| | - Keith P. Eidell
- Department of Biology, Boston College, Chestnut Hill, MA 02467, USA
| | - David J.P. Ferguson
- Nuffield Department of Clinical Laboratory Science, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, UK
| | | | - Manoj T. Duraisingh
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, MA 02115, USA
| | - Gabor T. Marth
- Department of Biology, Boston College, Chestnut Hill, MA 02467, USA
| | - Marc-Jan Gubbels
- Department of Biology, Boston College, Chestnut Hill, MA 02467, USA
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Tham WH, Healer J, Cowman AF. Erythrocyte and reticulocyte binding-like proteins of Plasmodium falciparum. Trends Parasitol 2011; 28:23-30. [PMID: 22178537 DOI: 10.1016/j.pt.2011.10.002] [Citation(s) in RCA: 129] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2011] [Revised: 10/11/2011] [Accepted: 10/11/2011] [Indexed: 11/30/2022]
Abstract
The global agenda for malaria eradication would benefit from development of a highly efficacious vaccine that protects against disease and interrupts transmission of Plasmodium falciparum. It is likely that such a vaccine will be multi-component, with antigens from different stages of the parasite life cycle. In this review, inclusion of blood stage antigens in such a vaccine is discussed. Erythrocyte binding-like (EBL) and P. falciparum reticulocyte binding-like (PfRh) proteins are reviewed with respect to their function in erythrocyte invasion, their role in eliciting antibodies contributing to protective immunity and reduction of invasion, leading subsequently to inhibition of parasite multiplication.
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Affiliation(s)
- Wai-Hong Tham
- Walter and Eliza Hall Institute of Medical Research, University of Melbourne, Parkville, VIC, Australia
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Four promising antigens, BgP32, BgP45, BgP47, and BgP50, for serodiagnosis of Babesia gibsoni infection were classified as B. gibsoni merozoite surface protein family. Parasitol Int 2011; 61:364-8. [PMID: 22172478 DOI: 10.1016/j.parint.2011.11.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Revised: 11/28/2011] [Accepted: 11/29/2011] [Indexed: 11/21/2022]
Abstract
We determined the molecular characteristics of four proteins, BgP32, BgP45, BgP47, and BgP50, of Babesia gibsoni. Localization by subcellular fractionations followed by Western blotting revealed that the corresponding native proteins belong to merozoite surface protein family of B. gibsoni (BgMSP). Moreover, antisera against either rBgP45 or rBgP47 cross-reacted with all the proteins of the BgMSP family on ELISA and IFAT analyses. Of the four candidate antigens, ELISA with rBgP45 yielded high sensitivity, and ELISA with rBgP32 resulted in high specificity and in concordance with IFAT results.
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Plasmodium falciparum merozoite invasion is inhibited by antibodies that target the PfRh2a and b binding domains. PLoS Pathog 2011; 7:e1002075. [PMID: 21698217 PMCID: PMC3116812 DOI: 10.1371/journal.ppat.1002075] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2010] [Accepted: 04/09/2011] [Indexed: 02/05/2023] Open
Abstract
Plasmodium falciparum, the causative agent of the most severe form of malaria in humans invades erythrocytes using multiple ligand-receptor interactions. The P. falciparum reticulocyte binding-like homologue proteins (PfRh or PfRBL) are important for entry of the invasive merozoite form of the parasite into red blood cells. We have analysed two members of this protein family, PfRh2a and PfRh2b, and show they undergo a complex series of proteolytic cleavage events before and during merozoite invasion. We show that PfRh2a undergoes a cleavage event in the transmembrane region during invasion consistent with activity of the membrane associated PfROM4 protease that would result in release of the ectodomain into the supernatant. We also show that PfRh2a and PfRh2b bind to red blood cells and have defined the erythrocyte-binding domain to a 15 kDa region at the N-terminus of each protein. Antibodies to this receptor-binding region block merozoite invasion demonstrating the important function of this domain. This region of PfRh2a and PfRh2b has potential in a combination vaccine with other erythrocyte binding ligands for induction of antibodies that would block a broad range of invasion pathways for P. falciparum into human erythrocytes. The causative agent of the most severe form of malaria in humans is the protozoan parasite Plasmodium falciparum. These parasites are carried by a mosquito that infects humans during feeding resulting in injection of sporozoite forms that infect and develop in the liver into the merozoite stage. The merozoites are released into the blood stream where they invade erythrocytes in which they can grow and divide. Invasion of the red blood cell by P. falciparum merozoites involves a cascade of protein-protein interactions. The P. falciparum reticulocyte binding-like homologue proteins (PfRh or PfRBL) are an important protein family involved in binding to specific receptors on the red blood cell. We have analysed two members of this protein family, PfRh2a and PfRh2b, and show that they undergo a complex series of cleavage events before and during merozoite invasion. We have defined the region of these ligands that bind red blood cells and show that antibodies to this receptor-binding region block merozoite invasion demonstrating the important function of this domain.
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Super-resolution dissection of coordinated events during malaria parasite invasion of the human erythrocyte. Cell Host Microbe 2011; 9:9-20. [PMID: 21238943 DOI: 10.1016/j.chom.2010.12.003] [Citation(s) in RCA: 258] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2010] [Revised: 10/01/2010] [Accepted: 12/10/2010] [Indexed: 11/21/2022]
Abstract
Erythrocyte invasion by the merozoite is an obligatory stage in Plasmodium parasite infection and essential to malaria disease progression. Attempts to study this process have been hindered by the poor invasion synchrony of merozoites from the only in vitro culture-adapted human malaria parasite, Plasmodium falciparum. Using fluorescence, three-dimensional structured illumination, and immunoelectron microscopy of filtered merozoites, we analyze cellular and molecular events underlying each discrete step of invasion. Monitoring the dynamics of these events revealed that commitment to the process is mediated through merozoite attachment to the erythrocyte, triggering all subsequent invasion events, which then proceed without obvious checkpoints. Instead, coordination of the invasion process involves formation of the merozoite-erythrocyte tight junction, which acts as a nexus for rhoptry secretion, surface-protein shedding, and actomyosin motor activation. The ability to break down each molecular step allows us to propose a comprehensive model for the molecular basis of parasite invasion.
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Plasmodium falciparum reticulocyte binding-like homologue protein 2 (PfRH2) is a key adhesive molecule involved in erythrocyte invasion. PLoS One 2011; 6:e17102. [PMID: 21386888 PMCID: PMC3046117 DOI: 10.1371/journal.pone.0017102] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2010] [Accepted: 01/20/2011] [Indexed: 11/19/2022] Open
Abstract
Erythrocyte invasion by Plasmodium merozoites is a complex, multistep process that is mediated by a number of parasite ligand-erythrocyte receptor interactions. One such family of parasite ligands includes the P. falciparum reticulocyte binding homologue (PfRH) proteins that are homologous with the P. vivax reticulocyte binding proteins and have been shown to play a role in erythrocyte invasion. There are five functional PfRH proteins of which only PfRH2a/2b have not yet been demonstrated to bind erythrocytes. In this study, we demonstrated that native PfRH2a/2b is processed near the N-terminus yielding fragments of 220 kDa and 80 kDa that exhibit differential erythrocyte binding specificities. The erythrocyte binding specificity of the 220 kDa processed fragment of native PfRH2a/2b was sialic acid-independent, trypsin resistant and chymotrypsin sensitive. This specific binding phenotype is consistent with previous studies that disrupted the PfRH2a/2b genes and demonstrated that PfRH2b is involved in a sialic acid independent, trypsin resistant, chymotrypsin sensitive invasion pathway. Interestingly, we found that the smaller 80 kDa PfRH2a/2b fragment is processed from the larger 220 kDa fragment and binds erythrocytes in a sialic acid dependent, trypsin resistant and chymotrypsin sensitive manner. Thus, the two processed fragments of PfRH2a/2b differed with respect to their dependence on sialic acids for erythrocyte binding. Further, we mapped the erythrocyte binding domain of PfRH2a/2b to a conserved 40 kDa N-terminal region (rPfRH240) in the ectodomain that is common to both PfRH2a and PfRH2b. We demonstrated that recombinant rPfRH240 bound human erythrocytes with the same specificity as the native 220 kDa processed protein. Moreover, antibodies generated against rPfRH240 blocked erythrocyte invasion by P. falciparum through a sialic acid independent pathway. PfRH2a/2b thus plays a key role in erythrocyte invasion and its conserved receptor-binding domain deserves attention as a promising candidate for inclusion in a blood-stage malaria vaccine.
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Santos JM, Soldati-Favre D. Invasion factors are coupled to key signalling events leading to the establishment of infection in apicomplexan parasites. Cell Microbiol 2011; 13:787-96. [DOI: 10.1111/j.1462-5822.2011.01585.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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