101
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Galinski MR, Lapp SA, Peterson MS, Ay F, Joyner CJ, LE Roch KG, Fonseca LL, Voit EO. Plasmodium knowlesi: a superb in vivo nonhuman primate model of antigenic variation in malaria. Parasitology 2018; 145:85-100. [PMID: 28712361 PMCID: PMC5798396 DOI: 10.1017/s0031182017001135] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Revised: 06/03/2017] [Accepted: 06/06/2017] [Indexed: 02/08/2023]
Abstract
Antigenic variation in malaria was discovered in Plasmodium knowlesi studies involving longitudinal infections of rhesus macaques (M. mulatta). The variant proteins, known as the P. knowlesi Schizont Infected Cell Agglutination (SICA) antigens and the P. falciparum Erythrocyte Membrane Protein 1 (PfEMP1) antigens, expressed by the SICAvar and var multigene families, respectively, have been studied for over 30 years. Expression of the SICA antigens in P. knowlesi requires a splenic component, and specific antibodies are necessary for variant antigen switch events in vivo. Outstanding questions revolve around the role of the spleen and the mechanisms by which the expression of these variant antigen families are regulated. Importantly, the longitudinal dynamics and molecular mechanisms that govern variant antigen expression can be studied with P. knowlesi infection of its mammalian and vector hosts. Synchronous infections can be initiated with established clones and studied at multi-omic levels, with the benefit of computational tools from systems biology that permit the integration of datasets and the design of explanatory, predictive mathematical models. Here we provide an historical account of this topic, while highlighting the potential for maximizing the use of P. knowlesi - macaque model systems and summarizing exciting new progress in this area of research.
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Affiliation(s)
- M R Galinski
- Emory Vaccine Center,Yerkes National Primate Research Center,Emory University,Atlanta,GA,USA
| | - S A Lapp
- Emory Vaccine Center,Yerkes National Primate Research Center,Emory University,Atlanta,GA,USA
| | - M S Peterson
- Emory Vaccine Center,Yerkes National Primate Research Center,Emory University,Atlanta,GA,USA
| | - F Ay
- La Jolla Institute for Allergy and Immunology,La Jolla,CA 92037,USA
| | - C J Joyner
- Emory Vaccine Center,Yerkes National Primate Research Center,Emory University,Atlanta,GA,USA
| | - K G LE Roch
- Department of Cell Biology & Neuroscience,Center for Disease and Vector Research,Institute for Integrative Genome Biology,University of California Riverside,CA 92521,USA
| | - L L Fonseca
- The Wallace H. Coulter Department of Biomedical Engineering,Georgia Institute of Technology and Emory University,Atlanta,Georgia,30332-2000,USA
| | - E O Voit
- The Wallace H. Coulter Department of Biomedical Engineering,Georgia Institute of Technology and Emory University,Atlanta,Georgia,30332-2000,USA
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102
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Rono MK, Nyonda MA, Simam JJ, Ngoi JM, Mok S, Kortok MM, Abdullah AS, Elfaki MM, Waitumbi JN, El-Hassan IM, Marsh K, Bozdech Z, Mackinnon MJ. Adaptation of Plasmodium falciparum to its transmission environment. Nat Ecol Evol 2017; 2:377-387. [PMID: 29255304 DOI: 10.1038/s41559-017-0419-9] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Accepted: 11/20/2017] [Indexed: 12/19/2022]
Abstract
Success in eliminating malaria will depend on whether parasite evolution outpaces control efforts. Here, we show that Plasmodium falciparum parasites (the deadliest of the species causing human malaria) found in low-transmission-intensity areas have evolved to invest more in transmission to new hosts (reproduction) and less in within-host replication (growth) than parasites found in high-transmission areas. At the cellular level, this adaptation manifests as increased production of reproductive forms (gametocytes) early in the infection at the expense of processes associated with multiplication inside red blood cells, especially membrane transport and protein trafficking. At the molecular level, this manifests as changes in the expression levels of genes encoding epigenetic and translational machinery. Specifically, expression levels of the gene encoding AP2-G-the transcription factor that initiates reproduction-increase as transmission intensity decreases. This is accompanied by downregulation and upregulation of genes encoding HDAC1 and HDA1-two histone deacetylases that epigenetically regulate the parasite's replicative and reproductive life-stage programmes, respectively. Parasites in reproductive mode show increased reliance on the prokaryotic translation machinery found inside the plastid-derived organelles. Thus, our dissection of the parasite's adaptive regulatory architecture has identified new potential molecular targets for malaria control.
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Affiliation(s)
- Martin K Rono
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya.,Pwani University Bioscience Research Centre, Pwani University, Kilifi, Kenya.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Mary A Nyonda
- Department of Microbiology and Molecular Medicine, Medical Faculty, University of Geneva, Geneva, Switzerland
| | | | - Joyce M Ngoi
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Sachel Mok
- Columbia University Medical Center, New York, NY, USA
| | - Moses M Kortok
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
| | | | - Mohammed M Elfaki
- Department of Microbiology and Parasitology, Faculty of Medicine, Jazan University, Gizan, Jazan, Saudi Arabia
| | - John N Waitumbi
- Walter Reed Army Institute of Research/Kenya Medical Research Institute, Kisumu, Kenya
| | - Ibrahim M El-Hassan
- Faculty of Public Health and Tropical Medicine, Jazan University, Gizan, Jazan, Saudi Arabia
| | - Kevin Marsh
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Zbynek Bozdech
- School of Biological Sciences, Nanyang Technological University, Singapore
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103
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Sherling ES, van Ooij C. Host cell remodeling by pathogens: the exomembrane system in Plasmodium-infected erythrocytes. FEMS Microbiol Rev 2017; 40:701-21. [PMID: 27587718 PMCID: PMC5007283 DOI: 10.1093/femsre/fuw016] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/18/2016] [Indexed: 12/22/2022] Open
Abstract
Malaria is caused by infection of erythrocytes by parasites of the genus Plasmodium. To survive inside erythrocytes, these parasites induce sweeping changes within the host cell, one of the most dramatic of which is the formation of multiple membranous compartments, collectively referred to as the exomembrane system. As an uninfected mammalian erythrocyte is devoid of internal membranes, the parasite must be the force and the source behind the formation of these compartments. Even though the first evidence of the presence these of internal compartments was obtained over a century ago, their functions remain mostly unclear, and in some cases completely unknown, and the mechanisms underlying their formation are still mysterious. In this review, we provide an overview of the different parts of the exomembrane system, describing the parasitophorous vacuole, the tubovesicular network, Maurer's clefts, the caveola-vesicle complex, J dots and other mobile compartments, and the small vesicles that have been observed in Plasmodium-infected cells. Finally, we combine the data into a simplified view of the exomembrane system and its relation to the alterations of the host erythrocyte. Plasmodium parasites remodel the host erythrocyte in various ways, including the formation of several membranous compartments, together referred to as the exomembrane system, within the erythrocyte cytosol that together are key to the sweeping changes in the host cell.
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Affiliation(s)
- Emma S Sherling
- The Francis Crick Institute, Mill Hill Laboratory, Mill Hill, London NW7 1AA, UK Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20852, USA
| | - Christiaan van Ooij
- The Francis Crick Institute, Mill Hill Laboratory, Mill Hill, London NW7 1AA, UK
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104
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Riggle BA, Miller LH, Pierce SK. Do we know enough to find an adjunctive therapy for cerebral malaria in African children? F1000Res 2017; 6:2039. [PMID: 29250318 PMCID: PMC5701444 DOI: 10.12688/f1000research.12401.1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/23/2017] [Indexed: 01/27/2023] Open
Abstract
Cerebral malaria is the deadliest complication of malaria, a febrile infectious disease caused by Plasmodium parasite. Any of the five human Plasmodium species can cause disease, but, for unknown reasons, in approximately 2 million cases each year P. falciparum progresses to severe disease, ultimately resulting in half a million deaths. The majority of these deaths are in children under the age of five. Currently, there is no way to predict which child will progress to severe disease and there are no adjunctive therapies to halt the symptoms after onset. Herein, we discuss what is known about the disease mechanism of one form of severe malaria, cerebral malaria, and how we might exploit this understanding to rescue children in the throes of cerebral disease.
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Affiliation(s)
- Brittany A Riggle
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, USA
| | - Louis H Miller
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, USA
| | - Susan K Pierce
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, USA
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105
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Nilsson Bark SK, Ahmad R, Dantzler K, Lukens AK, De Niz M, Szucs MJ, Jin X, Cotton J, Hoffmann D, Bric-Furlong E, Oomen R, Parrington M, Milner D, Neafsey DE, Carr SA, Wirth DF, Marti M. Quantitative Proteomic Profiling Reveals Novel Plasmodium falciparum Surface Antigens and Possible Vaccine Candidates. Mol Cell Proteomics 2017; 17:43-60. [PMID: 29162636 DOI: 10.1074/mcp.ra117.000076] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Revised: 09/20/2017] [Indexed: 12/30/2022] Open
Abstract
Despite recent efforts toward control and elimination, malaria remains a major public health problem worldwide. Plasmodium falciparum resistance against artemisinin, used in front line combination drugs, is on the rise, and the only approved vaccine shows limited efficacy. Combinations of novel and tailored drug and vaccine interventions are required to maintain the momentum of the current malaria elimination program. Current evidence suggests that strain-transcendent protection against malaria infection can be achieved using whole organism vaccination or with a polyvalent vaccine covering multiple antigens or epitopes. These approaches have been successfully applied to the human-infective sporozoite stage. Both systemic and tissue-specific pathology during infection with the human malaria parasite P. falciparum is caused by asexual blood stages. Tissue tropism and vascular sequestration are the result of specific binding interactions between antigens on the parasite-infected red blood cell (pRBC) surface and endothelial receptors. The major surface antigen and parasite ligand binding to endothelial receptors, PfEMP1 is encoded by about 60 variants per genome and shows high sequence diversity across strains. Apart from PfEMP1 and three additional variant surface antigen families RIFIN, STEVOR, and SURFIN, systematic analysis of the infected red blood cell surface is lacking. Here we present the most comprehensive proteomic investigation of the parasitized red blood cell surface so far. Apart from the known variant surface antigens, we identified a set of putative single copy surface antigens with low sequence diversity, several of which are validated in a series of complementary experiments. Further functional and immunological investigation is underway to test these novel P. falciparum blood stage proteins as possible vaccine candidates.
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Affiliation(s)
- Sandra K Nilsson Bark
- From the ‡Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts 02115
| | - Rushdy Ahmad
- §The Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142
| | - Kathleen Dantzler
- From the ‡Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts 02115.,¶Wellcome Centre for Molecular Parasitology, University of Glasgow, Glasgow G12 8TA, UK
| | - Amanda K Lukens
- From the ‡Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts 02115.,§The Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142
| | - Mariana De Niz
- ¶Wellcome Centre for Molecular Parasitology, University of Glasgow, Glasgow G12 8TA, UK
| | - Matthew J Szucs
- §The Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142
| | - Xiaoying Jin
- ‖Sanofi Biopharmaceutics Development, Framingham, Massachusetts 02142
| | - Joanne Cotton
- ‖Sanofi Biopharmaceutics Development, Framingham, Massachusetts 02142
| | | | | | - Ray Oomen
- **Sanofi Pasteur Biologics, Cambridge, Massachusetts 02139
| | | | - Dan Milner
- From the ‡Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts 02115.,‡‡Department of Pathology, Brigham and Women's Hospital, Boston, Massachusetts 02115
| | - Daniel E Neafsey
- §The Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142
| | - Steven A Carr
- §The Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142
| | - Dyann F Wirth
- From the ‡Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts 02115.,§The Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142
| | - Matthias Marti
- From the ‡Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts 02115; .,¶Wellcome Centre for Molecular Parasitology, University of Glasgow, Glasgow G12 8TA, UK
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106
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107
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Shabani E, Hanisch B, Opoka RO, Lavstsen T, John CC. Plasmodium falciparum EPCR-binding PfEMP1 expression increases with malaria disease severity and is elevated in retinopathy negative cerebral malaria. BMC Med 2017; 15:183. [PMID: 29025399 PMCID: PMC5639490 DOI: 10.1186/s12916-017-0945-y] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2017] [Accepted: 09/15/2017] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Expression of group A and the A-like subset of group B Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) is associated with severe malaria (SM). The diversity of var sequences combined with the challenges of distinct classification of patient pathologies has made studying the role of distinct PfEMP1 variants on malaria disease severity challenging. The application of retinopathy in the recent years has provided a further method to clinically evaluate children with cerebral malaria (CM). The question of whether children with clinical CM but no retinopathy represent a completely different disease process or a subgroup within the spectrum of CM remains an important question in malaria. In the current study, we use newly designed primer sets with the best coverage to date in a large cohort of children with SM to determine the role of var genes in malaria disease severity and especially CM as discriminated by retinopathy. METHODS We performed qRT-PCR targeting the different subsets of these var genes on samples from Ugandan children with CM (n = 98, of whom 50 had malarial retinopathy [RP] and 47 did not [RN]), severe malarial anemia (SMA, n = 47), and asymptomatic parasitemia (AP, n = 14). The primers used in this study were designed based on var sequences from 226 Illumina whole genome sequenced P. falciparum field isolates. RESULTS Increasing severity of illness was associated with increasing levels of endothelial protein C receptor (EPCR)-binding PfEMP1. EPCR-binding PfEMP1 transcript levels were highest in children with combined CM and SMA and then decreased by level of disease severity: RP CM > RN CM > SMA > AP. CONCLUSIONS The study findings indicate that PfEMP1 binding to EPCR is important in the pathogenesis of SM, including RN CM, and suggest that increased expression of EPCR-binding PfEMP1 is associated with progressively more severe disease. Agents that block EPCR-binding of PfEMP1 could provide novel interventions to prevent or decrease disease severity in malaria.
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Affiliation(s)
- Estela Shabani
- Ryan White Center for Pediatric Infectious Diseases and Global Health, Indiana University, 1044 W Walnut St R4 402D, Indianapolis, Indiana, USA.,Department of Pediatrics, Division of Global Pediatrics, University of Minnesota, Minneapolis, Minnesota, USA
| | | | - Robert O Opoka
- Department of Pediatrics and Child Health, Makerere University School of Medicine, Kampala, Uganda
| | - Thomas Lavstsen
- Centre for Medical Parasitology, Department of International Health, Immunology and Microbiology, University of Copenhagen and Department of Infectious Diseases, Copenhagen, Denmark
| | - Chandy C John
- Ryan White Center for Pediatric Infectious Diseases and Global Health, Indiana University, 1044 W Walnut St R4 402D, Indianapolis, Indiana, USA. .,Department of Pediatrics, Division of Global Pediatrics, University of Minnesota, Minneapolis, Minnesota, USA.
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108
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Rougeron V, Tiedje KE, Chen DS, Rask TS, Gamboa D, Maestre A, Musset L, Legrand E, Noya O, Yalcindag E, Renaud F, Prugnolle F, Day KP. Evolutionary structure of Plasmodium falciparum major variant surface antigen genes in South America: Implications for epidemic transmission and surveillance. Ecol Evol 2017; 7:9376-9390. [PMID: 29187975 PMCID: PMC5696401 DOI: 10.1002/ece3.3425] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Revised: 07/07/2017] [Accepted: 08/19/2017] [Indexed: 11/11/2022] Open
Abstract
Strong founder effects resulting from human migration out of Africa have led to geographic variation in single nucleotide polymorphisms (SNPs) and microsatellites (MS) of the malaria parasite, Plasmodium falciparum. This is particularly striking in South America where two major founder populations of P. falciparum have been identified that are presumed to have arisen from the transatlantic slave trade. Given the importance of the major variant surface antigen of the blood stages of P. falciparum as both a virulence factor and target of immunity, we decided to investigate the population genetics of the genes encoding “Plasmodium falciparum Erythrocyte Membrane Protein 1” (PfEMP1) among several countries in South America, in order to evaluate the transmission patterns of malaria in this continent. Deep sequencing of the DBLα domain of var genes from 128 P. falciparum isolates from five locations in South America was completed using a 454 high throughput sequencing protocol. Striking geographic variation in var DBLα sequences, similar to that seen for SNPs and MS markers, was observed. Colombia and French Guiana had distinct var DBLα sequences, whereas Peru and Venezuela showed an admixture. The importance of such geographic variation to herd immunity and malaria vaccination is discussed.
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Affiliation(s)
- Virginie Rougeron
- Department of Microbiology Division of Parasitology New York University School of Medicine New York NY USA.,MIVEGEC (Laboratoire Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle), UMR CNRS 5290/IRD 224 Université Montpellier 1 Université Montpellier 2 Montpellier France
| | - Kathryn E Tiedje
- Department of Microbiology Division of Parasitology New York University School of Medicine New York NY USA.,School of BioSciences Bio21 Institute/University of Melbourne Parkville Vic. Australia
| | - Donald S Chen
- Department of Microbiology Division of Parasitology New York University School of Medicine New York NY USA
| | - Thomas S Rask
- Department of Microbiology Division of Parasitology New York University School of Medicine New York NY USA.,School of BioSciences Bio21 Institute/University of Melbourne Parkville Vic. Australia
| | - Dionicia Gamboa
- Instituto de Medicina Tropical Alexander Von Humboldt and Departamento de Ciencias Celulares y Moleculares Facultad de Ciencias y Filosofia Universidad Peruana Cayetano Heredia Lima Peru
| | - Amanda Maestre
- Grupo Salud y Comunidad Facultad de Medicina Universidad de Antioquía Medellín Colombia
| | - Lise Musset
- Parasitology UnitInstitut Pasteur de Guyane Cayenne Cedex French Guiana
| | - Eric Legrand
- Parasitology UnitInstitut Pasteur de Guyane Cayenne Cedex French Guiana.,Unit of Genetics and Genomics on Insect Vectors Institut Pasteur Paris France
| | - Oscar Noya
- Centro para Estudios Sobre Malaria Instituto de Altos Estudios en Salud "Dr. Arnoldo Gabaldón" Ministerio del Poder Popular para la Salud and Instituto de Medicina Tropical Universidad Central de Venezuela Caracas Venezuela
| | - Erhan Yalcindag
- MIVEGEC (Laboratoire Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle), UMR CNRS 5290/IRD 224 Université Montpellier 1 Université Montpellier 2 Montpellier France
| | - François Renaud
- MIVEGEC (Laboratoire Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle), UMR CNRS 5290/IRD 224 Université Montpellier 1 Université Montpellier 2 Montpellier France
| | - Franck Prugnolle
- MIVEGEC (Laboratoire Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle), UMR CNRS 5290/IRD 224 Université Montpellier 1 Université Montpellier 2 Montpellier France
| | - Karen P Day
- Department of Microbiology Division of Parasitology New York University School of Medicine New York NY USA.,School of BioSciences Bio21 Institute/University of Melbourne Parkville Vic. Australia
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109
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Ruybal-Pesántez S, Tiedje KE, Tonkin-Hill G, Rask TS, Kamya MR, Greenhouse B, Dorsey G, Duffy MF, Day KP. Population genomics of virulence genes of Plasmodium falciparum in clinical isolates from Uganda. Sci Rep 2017; 7:11810. [PMID: 28924231 PMCID: PMC5603532 DOI: 10.1038/s41598-017-11814-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Accepted: 08/30/2017] [Indexed: 12/18/2022] Open
Abstract
Plasmodium falciparum causes a spectrum of malarial disease from asymptomatic to uncomplicated through to severe. Investigations of parasite virulence have associated the expression of distinct variants of the major surface antigen of the blood stages known as Pf EMP1 encoded by up to 60 var genes per genome. Looking at the population genomics of var genes in cases of uncomplicated malaria, we set out to determine if there was any evidence of a selective sweep of specific var genes or clonal epidemic structure related to the incidence of uncomplicated disease in children. By sequencing the conserved DBLα domain of var genes from six sentinel sites in Uganda we found that the parasites causing uncomplicated P. falciparum disease in children were highly diverse and that every child had a unique var DBLα repertoire. Despite extensive var DBLα diversity and minimal overlap between repertoires, specific DBLα types and groups were conserved at the population level across Uganda. This pattern was the same regardless of the geographic distance or malaria transmission intensity. These data lead us to propose that any parasite can cause uncomplicated malarial disease and that these diverse parasite repertoires are composed of both upsA and non-upsA var gene groups.
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Affiliation(s)
- Shazia Ruybal-Pesántez
- School of BioSciences, Bio21 Institute/University of Melbourne, Melbourne, Australia.,Department of Microbiology, New York University, New York, USA
| | - Kathryn E Tiedje
- School of BioSciences, Bio21 Institute/University of Melbourne, Melbourne, Australia.,Department of Microbiology, New York University, New York, USA
| | | | - Thomas S Rask
- School of BioSciences, Bio21 Institute/University of Melbourne, Melbourne, Australia.,Department of Microbiology, New York University, New York, USA
| | - Moses R Kamya
- School of Medicine, Makerere University College of Health Sciences, Kampala, Uganda
| | - Bryan Greenhouse
- Department of Medicine, University of California, San Francisco, USA
| | - Grant Dorsey
- Department of Medicine, University of California, San Francisco, USA
| | - Michael F Duffy
- School of BioSciences, Bio21 Institute/University of Melbourne, Melbourne, Australia
| | - Karen P Day
- School of BioSciences, Bio21 Institute/University of Melbourne, Melbourne, Australia. .,Department of Microbiology, New York University, New York, USA.
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110
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Chan JA, Stanisic DI, Duffy MF, Robinson LJ, Lin E, Kazura JW, King CL, Siba PM, Fowkes FJ, Mueller I, Beeson JG. Patterns of protective associations differ for antibodies to P. falciparum-infected erythrocytes and merozoites in immunity against malaria in children. Eur J Immunol 2017; 47:2124-2136. [PMID: 28833064 DOI: 10.1002/eji.201747032] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Revised: 07/09/2017] [Accepted: 08/16/2017] [Indexed: 11/10/2022]
Abstract
Acquired antibodies play an important role in immunity to P. falciparum malaria and are typically directed towards surface antigens expressed by merozoites and infected erythrocytes (IEs). The importance of specific IE surface antigens as immune targets remains unclear. We evaluated antibodies and protective associations in two cohorts of children in Papua New Guinea. We used genetically-modified P. falciparum to evaluate the importance of PfEMP1 and a P. falciparum isolate with a virulent phenotype. Our findings suggested that PfEMP1 was the dominant target of antibodies to the IE surface, including functional antibodies that promoted opsonic phagocytosis by monocytes. Antibodies were associated with increasing age and concurrent parasitemia, and were higher among children exposed to a higher force-of-infection as determined using molecular detection. Antibodies to IE surface antigens were consistently associated with reduced risk of malaria in both younger and older children. However, protective associations for antibodies to merozoite surface antigens were only observed in older children. This suggests that antibodies to IE surface antigens, particularly PfEMP1, play an earlier role in acquired immunity to malaria, whereas greater exposure is required for protective antibodies to merozoite antigens. These findings have implications for vaccine design and serosurveillance of malaria transmission and immunity.
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Affiliation(s)
- Jo-Anne Chan
- Macfarlane Burnet Institute for Medical Research and Public Health, Melbourne, Victoria, Australia.,Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia.,Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
| | - Danielle I Stanisic
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia.,Institute for Glycomics, Griffith University, Southport, Queensland, Australia
| | - Michael F Duffy
- Department of Medicine and Melbourne School of Public Health, University of Melbourne, Parkville, Victoria, Australia
| | - Leanne J Robinson
- Macfarlane Burnet Institute for Medical Research and Public Health, Melbourne, Victoria, Australia.,Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia.,Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea
| | - Enmoore Lin
- Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea
| | - James W Kazura
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, OH, USA
| | - Christopher L King
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, OH, USA
| | - Peter M Siba
- Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea
| | - Freya Ji Fowkes
- Macfarlane Burnet Institute for Medical Research and Public Health, Melbourne, Victoria, Australia.,Melbourne School of Public Health, University of Melbourne, Parkville, Victoria, Australia.,Department of Epidemiology and Preventive Medicine and Department of Infectious Diseases, Monash University, Melbourne, Victoria, Australia
| | - Ivo Mueller
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia.,Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea
| | - James G Beeson
- Macfarlane Burnet Institute for Medical Research and Public Health, Melbourne, Victoria, Australia.,Department of Medicine and Melbourne School of Public Health, University of Melbourne, Parkville, Victoria, Australia.,Department of Microbiology, Monash University, Melbourne, Victoria, Australia
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111
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Anderson DC, Lapp SA, Barnwell JW, Galinski MR. A large scale Plasmodium vivax- Saimiri boliviensis trophozoite-schizont transition proteome. PLoS One 2017; 12:e0182561. [PMID: 28829774 PMCID: PMC5567661 DOI: 10.1371/journal.pone.0182561] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2016] [Accepted: 07/20/2017] [Indexed: 11/18/2022] Open
Abstract
Plasmodium vivax is a complex protozoan parasite with over 6,500 genes and stage-specific differential expression. Much of the unique biology of this pathogen remains unknown, including how it modifies and restructures the host reticulocyte. Using a recently published P. vivax reference genome, we report the proteome from two biological replicates of infected Saimiri boliviensis host reticulocytes undergoing transition from the late trophozoite to early schizont stages. Using five database search engines, we identified a total of 2000 P. vivax and 3487 S. boliviensis proteins, making this the most comprehensive P. vivax proteome to date. PlasmoDB GO-term enrichment analysis of proteins identified at least twice by a search engine highlighted core metabolic processes and molecular functions such as glycolysis, translation and protein folding, cell components such as ribosomes, proteasomes and the Golgi apparatus, and a number of vesicle and trafficking related clusters. Database for Annotation, Visualization and Integrated Discovery (DAVID) v6.8 enriched functional annotation clusters of S. boliviensis proteins highlighted vesicle and trafficking-related clusters, elements of the cytoskeleton, oxidative processes and response to oxidative stress, macromolecular complexes such as the proteasome and ribosome, metabolism, translation, and cell death. Host and parasite proteins potentially involved in cell adhesion were also identified. Over 25% of the P. vivax proteins have no functional annotation; this group includes 45 VIR members of the large PIR family. A number of host and pathogen proteins contained highly oxidized or nitrated residues, extending prior trophozoite-enriched stage observations from S. boliviensis infections, and supporting the possibility of oxidative stress in relation to the disease. This proteome significantly expands the size and complexity of the known P. vivax and Saimiri host iRBC proteomes, and provides in-depth data that will be valuable for ongoing research on this parasite’s biology and pathogenesis.
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Affiliation(s)
- D. C. Anderson
- Bioscience Division, SRI International, Harrisonburg, VA, United States of America
- * E-mail:
| | - Stacey A. Lapp
- Emory Vaccine Center, Yerkes National Primate Research Center, Emory University, Atlanta, GA, United States of America
| | - John W. Barnwell
- Malaria Branch, Division of Parasitic Diseases, Centers for Disease Control and Prevention, Atlanta, GA, United States of America
| | - Mary R. Galinski
- Emory Vaccine Center, Yerkes National Primate Research Center, Emory University, Atlanta, GA, United States of America
- Department of Medicine, Division of Infectious Diseases, Emory University School of Medicine, Atlanta, GA, United States of America
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112
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Structural analysis of P. falciparum KAHRP and PfEMP1 complexes with host erythrocyte spectrin suggests a model for cytoadherent knob protrusions. PLoS Pathog 2017; 13:e1006552. [PMID: 28806784 PMCID: PMC5570508 DOI: 10.1371/journal.ppat.1006552] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Revised: 08/24/2017] [Accepted: 07/25/2017] [Indexed: 11/19/2022] Open
Abstract
Plasmodium falciparum Erythrocyte Membrane Protein 1 (PfEMP1) and Knob-associated Histidine-rich Protein (KAHRP) are directly linked to malaria pathology. PfEMP1 and KAHRP cluster on protrusions (knobs) on the P. falciparum-infected erythrocyte surface and enable pathogenic cytoadherence of infected erythrocytes to the host microvasculature, leading to restricted blood flow, oxygen deprivation and damage of tissues. Here we characterize the interactions of PfEMP1 and KAHRP with host erythrocyte spectrin using biophysical, structural and computational approaches. These interactions assist knob formation and, thus, promote cytoadherence. We show that the folded core of the PfEMP1 cytosolic domain interacts broadly with erythrocyte spectrin but shows weak, residue-specific preference for domain 17 of α spectrin, which is proximal to the erythrocyte cytoskeletal junction. In contrast, a protein sequence repeat region in KAHRP preferentially associates with domains 10–14 of β spectrin, proximal to the spectrin–ankyrin complex. Structural models of PfEMP1 and KAHRP with spectrin combined with previous microscopy and protein interaction data suggest a model for knob architecture. Formation of cytoadherent knobs on the surface of P. falciparum infected erythrocytes correlates with malaria pathology. Two parasite proteins central for knob formation and cytoadherence, KAHRP and PfEMP1, have previously been shown to bind the erythrocyte cytoskeleton. Both KAHRP and PfEMP1 include large segments of protein disorder, which have previously hampered their analysis. In this study we use biophysics and structural biology tools to analyze the interactions between these proteins and host spectrin. We devise a novel computational tool to help us towards this goal that may be broadly applicable to characterizing other complexes of widespread, disordered Plasmodial proteins and host components. We derive atomistic models of KAHRP–spectrin and PfEMP1 –spectrin complexes, and integrate these into an emerging model of knob architecture.
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113
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Knockdown of the Plasmodium falciparum SURFIN4.1 antigen leads to an increase of its cognate transcript. PLoS One 2017; 12:e0183129. [PMID: 28800640 PMCID: PMC5553854 DOI: 10.1371/journal.pone.0183129] [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: 03/23/2017] [Accepted: 07/31/2017] [Indexed: 11/24/2022] Open
Abstract
The genome of the malaria parasite Plasmodium falciparum contains the surf gene family which encodes large transmembrane proteins of unknown function. While some surf alleles appear to be expressed in sexual stages, others occur in asexual blood stage forms and may be associated to virulence-associated processes and undergo transcriptional switching. We accessed the transcription of surf genes along multiple invasions by real time PCR. Based on the observation of persistent expression of gene surf4.1, we created a parasite line which expresses a conditionally destabilized SURFIN4.1 protein. Upon destabilization of the protein, no interference of parasite growth or morphological changes were detected. However, we observed a strong increase in the transcript quantities of surf4.1 and sometimes of other surf genes in knocked-down parasites. While this effect was reversible when SURFIN4.1 was stabilized again after a few days of destabilization, longer destabilization periods resulted in a transcriptional switch away from surf4.1. When we tested if a longer transcript half-life was responsible for increased transcript detection in SURFIN4.1 knocked-down parasites, no alteration was found compared to control parasite lines. This suggests a specific feedback of the expressed SURFIN protein to its transcript pointing to a novel type of regulation, inedited in Plasmodium.
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114
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Kim SH, Bae YA, Seoh JY, Yang HJ. Isolation and Characterization of Vaccine Candidate Genes Including CSP and MSP1 in Plasmodium yoelii. THE KOREAN JOURNAL OF PARASITOLOGY 2017; 55:255-265. [PMID: 28719950 PMCID: PMC5546161 DOI: 10.3347/kjp.2017.55.3.255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Revised: 06/19/2017] [Accepted: 06/20/2017] [Indexed: 11/23/2022]
Abstract
Malaria is an infectious disease affecting humans, which is transmitted by the bite of Anopheles mosquitoes harboring sporozoites of parasitic protozoans belonging to the genus Plasmodium. Despite past achievements to control the protozoan disease, malaria still remains a significant health threat up to now. In this study, we cloned and characterized the full-unit Plasmodium yoelii genes encoding merozoite surface protein 1 (MSP1), circumsporozoite protein (CSP), and Duffy-binding protein (DBP), each of which can be applied for investigations to obtain potent protective vaccines in the rodent malaria model, due to their specific expression patterns during the parasite life cycle. Recombinant fragments corresponding to the middle and C-terminal regions of PyMSP1 and PyCSP, respectively, displayed strong reactivity against P. yoelii-infected mice sera. Specific native antigens invoking strong humoral immune response during the primary and secondary infections of P. yoelii were also abundantly detected in experimental ICR mice. The low or negligible parasitemia observed in the secondary infected mice was likely to result from the neutralizing action of the protective antibodies. Identification of these antigenic proteins might provide the necessary information and means to characterize additional vaccine candidate antigens, selected solely on their ability to produce the protective antibodies.
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Affiliation(s)
- Seon-Hee Kim
- Department of Parasitology, Ewha Womans University School of Medicine, Seoul 07985, Korea
| | - Young-An Bae
- Department of Microbiology, Gachon University College of Medicine, Incheon 21936, Korea
| | - Ju-Young Seoh
- Department of Microbiology, Ewha Womans University School of Medicine, Seoul 07985, Korea
| | - Hyun-Jong Yang
- Department of Parasitology, Ewha Womans University School of Medicine, Seoul 07985, Korea
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Abstract
Malaria is a significant threat throughout the developing world. Among the most fascinating aspects of the protozoan parasites responsible for this disease are the methods they employ to avoid the immune system and perpetuate chronic infections. Key among these is antigenic variation: By systematically altering antigens that are displayed to the host's immune system, the parasite renders the adaptive immune response ineffective. For Plasmodium falciparum, the species responsible for the most severe form of human malaria, this process involves a complicated molecular mechanism that results in continuously changing patterns of variant-antigen-encoding gene expression. Although many features of this process remain obscure, significant progress has been made in recent years to decipher various molecular aspects of the regulatory cascade that causes chronic infection.
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Affiliation(s)
- Kirk W Deitsch
- Department of Microbiology and Immunology, Weill Medical College of Cornell University, New York, NY 10065;
| | - Ron Dzikowski
- Department of Microbiology and Molecular Genetics, Institute for Medical Research Israel-Canada and Kuvin Center for the Study of Infectious and Tropical Diseases, Hebrew University Hadassah Medical School, Jerusalem 91120, Israel;
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116
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Abstract
Organisms with identical genome sequences can show substantial differences in their phenotypes owing to epigenetic changes that result in different use of their genes. Epigenetic regulation of gene expression plays a key role in the control of several fundamental processes in the biology of malaria parasites, including antigenic variation and sexual differentiation. Some of the histone modifications and chromatin-modifying enzymes that control the epigenetic states of malaria genes have been characterized, and their functions are beginning to be unraveled. The fundamental principles of epigenetic regulation of gene expression appear to be conserved between malaria parasites and model eukaryotes, but important peculiarities exist. Here, we review the current knowledge of malaria epigenetics and discuss how it can be exploited for the development of new molecular markers and new types of drugs that may contribute to malaria eradication efforts.
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Affiliation(s)
- Alfred Cortés
- ISGlobal, Barcelona Centre for International Health Research (CRESIB), Hospital Clínic - Universitat de Barcelona, Barcelona, Catalonia 08036, Spain.,ICREA, Barcelona, Catalonia 08010, Spain
| | - Kirk W Deitsch
- Department of Microbiology and Immunology, Weill Medical College of Cornell University, New York, New York 10065
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117
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Mackinnon MJ, Read AF. GENETIC RELATIONSHIPS BETWEEN PARASITE VIRULENCE AND TRANSMISSION IN THE RODENT MALARIA PLASMODIUM CHABAUDI. Evolution 2017; 53:689-703. [PMID: 28565637 DOI: 10.1111/j.1558-5646.1999.tb05364.x] [Citation(s) in RCA: 149] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/1998] [Accepted: 01/08/1999] [Indexed: 01/22/2023]
Abstract
Many parasites evolve to become virulent rather than benign mutualists. One of the major theoretical models of parasite virulence postulates that this is because rapid within-host replication rates are necessary for successful transmission (parasite fitness) and that virulence (damage to the host) is an unavoidable consequence of this rapid replication. Two fundamental assumptions underlying this so-called evolutionary trade-off model have rarely been tested empirically: (1) that higher replication rates lead to higher levels of virulence; and (2) that higher replication rates lead to higher transmission. Both of these relationships must have a genetic basis for this evolutionary hypothesis to be relevant. These assumptions were tested in the rodent malaria parasite, Plasmodium chabaudi, by examining genetic relationships between virulence and transmission traits across a population of eight parasite clones isolated from the wild. Each clone was injected into groups of inbred mice in a controlled laboratory environment, and replication rate (measured by maximum asexual parasitemia), virulence (measured by live-weight loss and degree of anemia in the mouse), and transmission (measured by density of sexual forms, gametocytes, in the blood and proportion of mosquitoes infected after taking a blood-meal from the mouse) were assessed. It was found that clones differed widely in these traits and these clone differences were repeatable over successive blood passages. Virulence traits were strongly phenotypically and genetically (i.e., across clones) correlated to maximum parasitemia thus supporting the first assumption that rapid replication causes higher virulence. Transmission traits were also positively phenotypically and genetically correlated to parasitemia, which supports the second assumption that rapid replication leads to higher transmission. Thus, two assumptions of the parasite-centered trade-off model of the evolution of virulence were shown to be justified in malaria parasites.
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Affiliation(s)
- Margaret J Mackinnon
- Institute of Cell, Animal and Population Biology, University of Edinburgh, King's Buildings, West Mains Road, Edinburgh, EH9 3JT, United Kingdom
| | - Andrew F Read
- Institute of Cell, Animal and Population Biology, University of Edinburgh, King's Buildings, West Mains Road, Edinburgh, EH9 3JT, United Kingdom
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118
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Pehrson C, Salanti A, Theander TG, Nielsen MA. Pre-clinical and clinical development of the first placental malaria vaccine. Expert Rev Vaccines 2017; 16:613-624. [PMID: 28434376 DOI: 10.1080/14760584.2017.1322512] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
INTRODUCTION Malaria during pregnancy is a massive health problem in endemic areas. Placental malaria infections caused by Plasmodium falciparum are responsible for up to one million babies being born with a low birth weight every year. Significant efforts have been invested into preventing the condition. Areas covered: Pub Med was searched using the broad terms 'malaria parasite placenta' to identify studies of interactions between parasite and host, 'prevention of placental malaria' to identify current strategies to prevent placental malaria, and 'placental malaria vaccine' to identify pre-clinical vaccine development. However, all papers from these searches were not systematically included. Expert commentary: The first phase I clinical trials of vaccines are well underway. Trials testing efficacy are more complicated to carry out as only women that are exposed to parasites during pregnancy will contribute to endpoint measurements, further it may require extensive follow-up to establish protection. Future second generation vaccines may overcome the inherent challenges in making an effective placental malaria vaccine.
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Affiliation(s)
- Caroline Pehrson
- a Centre for Medical Parasitology at Department of Immunology and Microbiology, Faculty of Health and Medical Science , University of Copenhagen , Copenhagen , Denmark.,b Department of Infectious Diseases , Copenhagen University Hospital (Rigshospitalet) , Copenhagen , Denmark
| | - Ali Salanti
- a Centre for Medical Parasitology at Department of Immunology and Microbiology, Faculty of Health and Medical Science , University of Copenhagen , Copenhagen , Denmark.,b Department of Infectious Diseases , Copenhagen University Hospital (Rigshospitalet) , Copenhagen , Denmark
| | - Thor G Theander
- a Centre for Medical Parasitology at Department of Immunology and Microbiology, Faculty of Health and Medical Science , University of Copenhagen , Copenhagen , Denmark.,b Department of Infectious Diseases , Copenhagen University Hospital (Rigshospitalet) , Copenhagen , Denmark
| | - Morten A Nielsen
- a Centre for Medical Parasitology at Department of Immunology and Microbiology, Faculty of Health and Medical Science , University of Copenhagen , Copenhagen , Denmark.,b Department of Infectious Diseases , Copenhagen University Hospital (Rigshospitalet) , Copenhagen , Denmark
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119
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Babamale OA, Ugbomoiko US, Heukelbach J. High prevalence of Plasmodium falciparum and soil-transmitted helminth co-infections in a periurban community in Kwara State, Nigeria. J Infect Public Health 2017; 11:48-53. [PMID: 28442321 DOI: 10.1016/j.jiph.2017.03.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2016] [Revised: 02/10/2017] [Accepted: 03/25/2017] [Indexed: 10/19/2022] Open
Abstract
Prevalence of malaria and soil-transmitted helminth infections, and the burden of disease are enormous in sub-Saharan Africa. Co-infections aggravate the clinical outcome, but are common due to an overlap of endemic areas. A cross-sectional survey was conducted to assess prevalence, intensity of infection and association between malaria and soil-transmitted helminth infections in a typical periurban community in Kwara State. Fresh blood and faecal samples were examined using thick blood film and Kato-Katz smear techniques. A total of 383/471 study participants (81.3%) were infected with at least one parasite species, with the following prevalences and mean infection intensities: Plasmodium falciparum 63.7% (2313.6 parasites/μl); Ascaris lumbricoides 63.1% (3152.1 epg); Trichuris trichiura 53.3% (1043.5 epg); and hookworms 30.1% (981.7 epg). Sixty-three percent of the study population were co-infected with two or more parasite species. The prevalence of ascariasis was significantly higher in individuals infected with P. falciparum (adjusted OR: 5.87; 95% CI: 3.30-10.42). Heavy A. lumbricoides and T. trichiura infections were associated with high P. falciparum parasitaemia. Co-endemicity of malaria and soil transmitted helminth infections is an important public health problem in the study area. Multi-target integrated approaches focusing on disease intervention are essential to mitigate morbidity caused by multiple infections.
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Affiliation(s)
| | - Uade S Ugbomoiko
- Parasitology Unit, Department of Zoology, University of Ilorin, Ilorin, Nigeria.
| | - Jorg Heukelbach
- College of Public Health, Medical and Veterinary Sciences, Division of Tropical Health and Medicine, James Cook University, Townsville, Queensland, Australia; Department of Community Health, School of Medicine, Federal University of Ceará, Brazil
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Thylur RP, Wu X, Gowda NM, Punnath K, Neelgund SE, Febbraio M, Gowda DC. CD36 receptor regulates malaria-induced immune responses primarily at early blood stage infection contributing to parasitemia control and resistance to mortality. J Biol Chem 2017; 292:9394-9408. [PMID: 28416609 DOI: 10.1074/jbc.m117.781294] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Revised: 04/12/2017] [Indexed: 12/31/2022] Open
Abstract
In malaria, CD36 plays several roles, including mediating parasite sequestration to host organs, phagocytic clearance of parasites, and regulation of immunity. Although the functions of CD36 in parasite sequestration and phagocytosis have been clearly defined, less is known about its role in malaria immunity. Here, to understand the function of CD36 in malaria immunity, we studied parasite growth, innate and adaptive immune responses, and host survival in WT and Cd36-/- mice infected with a non-lethal strain of Plasmodium yoelii Compared with Cd36-/- mice, WT mice had lower parasitemias and were resistant to death. At early but not at later stages of infection, WT mice had higher circulatory proinflammatory cytokines and lower anti-inflammatory cytokines than Cd36-/- mice. WT mice showed higher frequencies of proinflammatory cytokine-producing and lower frequencies of anti-inflammatory cytokine-producing dendritic cells (DCs) and natural killer cells than Cd36-/- mice. Cytokines produced by co-cultures of DCs from infected mice and ovalbumin-specific, MHC class II-restricted α/β (OT-II) T cells reflected CD36-dependent DC function. WT mice also showed increased Th1 and reduced Th2 responses compared with Cd36-/- mice, mainly at early stages of infection. Furthermore, in infected WT mice, macrophages and neutrophils expressed higher levels of phagocytic receptors and showed enhanced phagocytosis of parasite-infected erythrocytes than those in Cd36-/- mice in an IFN-γ-dependent manner. However, there were no differences in malaria-induced humoral responses between WT and Cd36-/- mice. Overall, the results show that CD36 plays a significant role in controlling parasite burden by contributing to proinflammatory cytokine responses by DCs and natural killer cells, Th1 development, phagocytic receptor expression, and phagocytic activity.
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Affiliation(s)
- Ramesh P Thylur
- From the Department of Biochemistry and Molecular Biology, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033 and
| | - Xianzhu Wu
- From the Department of Biochemistry and Molecular Biology, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033 and
| | - Nagaraj M Gowda
- From the Department of Biochemistry and Molecular Biology, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033 and
| | - Kishore Punnath
- From the Department of Biochemistry and Molecular Biology, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033 and
| | - Shivayogeeshwara E Neelgund
- From the Department of Biochemistry and Molecular Biology, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033 and
| | - Maria Febbraio
- the Department of Dentistry, University of Alberta, Edmonton, Alberta T6G 2E1, Canada
| | - D Channe Gowda
- From the Department of Biochemistry and Molecular Biology, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033 and
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121
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Three Is a Crowd – New Insights into Rosetting in Plasmodium falciparum. Trends Parasitol 2017; 33:309-320. [DOI: 10.1016/j.pt.2016.12.012] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Revised: 12/17/2016] [Accepted: 12/19/2016] [Indexed: 12/29/2022]
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The Severity of Plasmodium falciparum Infection Is Associated with Transcript Levels of var Genes Encoding Endothelial Protein C Receptor-Binding P. falciparum Erythrocyte Membrane Protein 1. Infect Immun 2017; 85:IAI.00841-16. [PMID: 28138022 DOI: 10.1128/iai.00841-16] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Accepted: 01/23/2017] [Indexed: 11/20/2022] Open
Abstract
By attaching infected erythrocytes to the vascular lining, Plasmodium falciparum parasites leave blood circulation and avoid splenic clearance. This sequestration is central to pathogenesis. Severe malaria is associated with parasites expressing an antigenically distinct P. falciparum erythrocyte membrane protein 1 (PfEMP1) subset mediating binding to endothelial receptors. Previous studies indicate that PfEMP1 adhesins with so-called CIDRα1 domains capable of binding endothelial protein C receptor (EPCR) constitute the PfEMP1 subset associated with severe pediatric malaria. To analyze the relative importance of different subtypes of CIDRα1 domains, we compared Pfemp1 transcript levels in children with severe malaria (including 9 fatal and 114 surviving cases), children hospitalized with uncomplicated malaria (n = 42), children with mild malaria not requiring hospitalization (n = 10), and children with parasitemia and no ongoing fever (n = 12). High levels of transcripts encoding EPCR-binding PfEMP1 were found in patients with symptomatic infections, and the abundance of these transcripts increased with disease severity. The compositions of CIDRα1 subtype transcripts varied markedly between patients, and none of the subtypes were dominant. Transcript-level analyses targeting other domain types indicated that subtypes of DBLβ or DBLζ domains might mediate binding phenomena that, in conjunction with EPCR binding, could contribute to pathogenesis. These observations strengthen the rationale for targeting the PfEMP1-EPCR interaction by vaccines and adjunctive therapies. Interventions should target EPCR binding of all CIDRα1 subtypes.
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Argy N, Bertin G, Milet J, Hubert V, Clain J, Cojean S, Houzé P, Tuikue-Ndam N, Kendjo E, Deloron P, Houzé S, Matheron S, Casalino E, Wolff M, Delaval A, Agnamey P, Durand R, Pilo J, Rapp C, Faucher J, Cuisenier B, Poilane I, Bemba D, Roide A, Debourgogne A, Thibault M, Toubas D, Patoz P, De Gentile L, Pons D, Hurst J, Lohmann C, Bigel M, Godineau N, Thouvenin M, Dunand J, Ait-Ammar N, Angoulvant A, Dahane N, Lefevre M, Murat J, Garnaud C, Dannaoui E, Botterel F, Dutoit E, Dardé M, Ichou H, Branger C, Penn P, Angebault C, Morio F, Bret L, Thellier M, Mouri O, Cateau E, Siriez J, Fenneteau O, Revest M, Belaz S, Belkadi G, Hamane S, Bretagne S, Aboubacar A, Leloup G, Develoux M, Lapillonne H, Eloy O, Nevez G, Raffenot D, Buret B, Desoubeaux G, Goepp A. Preferential expression of domain cassettes 4, 8 and 13 of Plasmodium falciparum erythrocyte membrane protein 1 in severe malaria imported in France. Clin Microbiol Infect 2017; 23:211.e1-211.e4. [DOI: 10.1016/j.cmi.2016.10.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2016] [Revised: 10/06/2016] [Accepted: 10/12/2016] [Indexed: 11/25/2022]
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Pathogenicity Determinants of the Human Malaria Parasite Plasmodium falciparum Have Ancient Origins. mSphere 2017; 2:mSphere00348-16. [PMID: 28101534 PMCID: PMC5227068 DOI: 10.1128/msphere.00348-16] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Accepted: 12/21/2016] [Indexed: 11/20/2022] Open
Abstract
Cytoadhesion of P. falciparum-infected erythrocytes in the microcirculation is a major virulence determinant. P. falciparum is descended from a subgenus of parasites that also infect chimpanzees and gorillas and exhibits strict host species specificity. Despite their high genetic similarity to P. falciparum, it is unknown whether ape parasites encode adhesion properties similar to those of P. falciparum or are as virulent in their natural hosts. Consequently, it has been unclear when virulent adhesion traits arose in P. falciparum and how long they have been present in the parasite population. It is also unknown whether cytoadhesive interactions pose a barrier to cross-species transmission. We show that parasite domains from the chimpanzee malaria parasite P. reichenowi bind human receptors with specificity similar to that of P. falciparum. Our findings suggest that parasite adhesion traits associated with both mild and severe malaria have much earlier origins than previously appreciated and have important implications for virulence evolution in a major human pathogen. Plasmodium falciparum, the most deadly of the human malaria parasites, is a member of the Laverania subgenus that also infects African Great Apes. The virulence of P. falciparum is related to cytoadhesion of infected erythrocytes in microvasculature, but the origin of dangerous parasite adhesion traits is poorly understood. To investigate the evolutionary history of the P. falciparum cytoadhesion pathogenicity determinant, we studied adhesion domains from the chimpanzee malaria parasite P. reichenowi. We demonstrate that the P. reichenowi var gene repertoire encodes cysteine-rich interdomain region (CIDR) domains which bind human CD36 and endothelial protein C receptor (EPCR) with the same levels of affinity and at binding sites similar to those bound by P. falciparum. Moreover, P. reichenowi domains interfere with the protective function of the activated protein C-EPCR pathway on endothelial cells, a presumptive virulence trait in humans. These findings provide evidence for ancient evolutionary origins of two key cytoadhesion properties of P. falciparum that contribute to human infection and pathogenicity. IMPORTANCE Cytoadhesion of P. falciparum-infected erythrocytes in the microcirculation is a major virulence determinant. P. falciparum is descended from a subgenus of parasites that also infect chimpanzees and gorillas and exhibits strict host species specificity. Despite their high genetic similarity to P. falciparum, it is unknown whether ape parasites encode adhesion properties similar to those of P. falciparum or are as virulent in their natural hosts. Consequently, it has been unclear when virulent adhesion traits arose in P. falciparum and how long they have been present in the parasite population. It is also unknown whether cytoadhesive interactions pose a barrier to cross-species transmission. We show that parasite domains from the chimpanzee malaria parasite P. reichenowi bind human receptors with specificity similar to that of P. falciparum. Our findings suggest that parasite adhesion traits associated with both mild and severe malaria have much earlier origins than previously appreciated and have important implications for virulence evolution in a major human pathogen.
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Duffy MF, Tang J, Sumardy F, Nguyen HHT, Selvarajah SA, Josling GA, Day KP, Petter M, Brown GV. Activation and clustering of a Plasmodium falciparum var gene are affected by subtelomeric sequences. FEBS J 2016; 284:237-257. [PMID: 27860263 DOI: 10.1111/febs.13967] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Revised: 10/12/2016] [Accepted: 11/15/2016] [Indexed: 11/30/2022]
Abstract
The Plasmodium falciparum var multigene family encodes the cytoadhesive, variant antigen PfEMP1. P. falciparum antigenic variation and cytoadhesion specificity are controlled by epigenetic switching between the single, or few, simultaneously expressed var genes. Most var genes are maintained in perinuclear clusters of heterochromatic telomeres. The active var gene(s) occupy a single, perinuclear var expression site. It is unresolved whether the var expression site forms in situ at a telomeric cluster or whether it is an extant compartment to which single chromosomes travel, thus controlling var switching. Here we show that transcription of a var gene did not require decreased colocalisation with clusters of telomeres, supporting var expression site formation in situ. However following recombination within adjacent subtelomeric sequences, the same var gene was persistently activated and did colocalise less with telomeric clusters. Thus, participation in stable, heterochromatic, telomere clusters and var switching are independent but are both affected by subtelomeric sequences. The var expression site colocalised with the euchromatic mark H3K27ac to a greater extent than it did with heterochromatic H3K9me3. H3K27ac was enriched within the active var gene promoter even when the var gene was transiently repressed in mature parasites and thus H3K27ac may contribute to var gene epigenetic memory.
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Affiliation(s)
- Michael F Duffy
- Department of Medicine, Royal Melbourne Hospital, The University of Melbourne at The Peter Doherty Institute for Infection and Immunity, Victoria, Australia.,The School of BioSciences, Bio21, The University of Melbourne, Victoria, Australia
| | - Jingyi Tang
- Department of Medicine, Royal Melbourne Hospital, The University of Melbourne at The Peter Doherty Institute for Infection and Immunity, Victoria, Australia.,The School of BioSciences, Bio21, The University of Melbourne, Victoria, Australia
| | - Fransisca Sumardy
- Department of Medicine, Royal Melbourne Hospital, The University of Melbourne at The Peter Doherty Institute for Infection and Immunity, Victoria, Australia.,The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
| | - Hanh H T Nguyen
- Department of Medicine, Royal Melbourne Hospital, The University of Melbourne at The Peter Doherty Institute for Infection and Immunity, Victoria, Australia.,The School of BioSciences, Bio21, The University of Melbourne, Victoria, Australia
| | - Shamista A Selvarajah
- Department of Medicine, Royal Melbourne Hospital, The University of Melbourne at The Peter Doherty Institute for Infection and Immunity, Victoria, Australia.,The School of BioSciences, Bio21, The University of Melbourne, Victoria, Australia
| | - Gabrielle A Josling
- Department of Medicine, Royal Melbourne Hospital, The University of Melbourne at The Peter Doherty Institute for Infection and Immunity, Victoria, Australia.,Department of Biochemistry and Molecular Biology, The Pennsylvania State University, State College, PA, USA
| | - Karen P Day
- The School of BioSciences, Bio21, The University of Melbourne, Victoria, Australia
| | - Michaela Petter
- Department of Medicine, Royal Melbourne Hospital, The University of Melbourne at The Peter Doherty Institute for Infection and Immunity, Victoria, Australia.,The School of BioSciences, Bio21, The University of Melbourne, Victoria, Australia
| | - Graham V Brown
- The Nossal Institute for Global Health, The University of Melbourne, Victoria, Australia
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127
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Newbold CI, Craig AG, Kyes S, Berendt AR, Snow RW, Peshu N, Marsh K. PfEMP1, polymorphism and pathogenesis. ANNALS OF TROPICAL MEDICINE AND PARASITOLOGY 2016. [DOI: 10.1080/00034983.1997.11813173] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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128
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Brown WC, McElwain TF, Hötzel I, Ruef BJ, Rice-Ficht AC, Stich RW, Suarez CE, Estes DM, Palmer GH. Immunodominant T-cell antigens and epitopes ofBabesia bovisandBabesia bigemina. ANNALS OF TROPICAL MEDICINE AND PARASITOLOGY 2016. [DOI: 10.1080/00034983.1998.11813305] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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129
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Abstract
Parasites of the genus Plasmodium have a complex life cycle. They alternate between their final mosquito host and their intermediate hosts. The parasite can be either extra- or intracellular, depending on the stage of development. By modifying their shape, motility, and metabolic requirements, the parasite adapts to the different environments in their different hosts. The parasite has evolved to escape the multiple immune mechanisms in the host that try to block parasite development at the different stages of their development. In this article, we describe the mechanisms reported thus far that allow the Plasmodium parasite to evade innate and adaptive immune responses.
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Affiliation(s)
- Laurent Rénia
- Singapore Immunology Network, Agency for Science, Technology and Research (A*STAR), Singapore
| | - Yun Shan Goh
- Singapore Immunology Network, Agency for Science, Technology and Research (A*STAR), Singapore
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130
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Stanton A, Harris LM, Graham G, Merrick CJ. Recombination events among virulence genes in malaria parasites are associated with G-quadruplex-forming DNA motifs. BMC Genomics 2016; 17:859. [PMID: 27809775 PMCID: PMC5093961 DOI: 10.1186/s12864-016-3183-3] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Accepted: 10/21/2016] [Indexed: 11/10/2022] Open
Abstract
Background Malaria parasites of the genus Plasmodium possess large hyper-variable families of antigen-encoding genes. These are often variantly-expressed and are major virulence factors for immune evasion and the maintenance of chronic infections. Recombination and diversification of these gene families occurs readily, and may be promoted by G-quadruplex (G4) DNA motifs within and close to the variant genes. G4s have been shown to cause replication fork stalling, DNA breakage and recombination in model systems, but these motifs remain largely unstudied in Plasmodium. Results We examined the nature and distribution of putative G4-forming sequences in multiple Plasmodium genomes, finding that their co-distribution with variant gene families is conserved across different Plasmodium species that have different types of variant gene families. In P. falciparum, where a large set of recombination events that occurred over time in cultured parasites has been mapped, we found a strong spatial association between these recombination events and putative G4-forming sequences. Finally, we searched Plasmodium genomes for the three classes of helicase that can unwind G4s: Plasmodium spp. have no identifiable homologue of the highly efficient G4 helicase PIF1, but they do encode two putative RecQ helicases and one homologue of the RAD3-family helicase FANCJ. Conclusions Our analyses, conducted at the whole-genome level in multiple species of Plasmodium, support the concept that G4s are likely to be involved in recombination and diversification of antigen-encoding gene families in this important protozoan pathogen. Electronic supplementary material The online version of this article (doi:10.1186/s12864-016-3183-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Adam Stanton
- School of Computing and Mathematics, Faculty of Natural Sciences, Keele University, Keele, Staffordshire, ST55BG, UK
| | - Lynne M Harris
- Centre for Applied Entomology and Parasitology, Faculty of Natural Sciences, Keele University, Keele, Staffordshire, ST55BG, UK
| | - Gemma Graham
- School of Medicine, Keele University, Keele, Staffordshire, ST55BG, UK
| | - Catherine J Merrick
- Centre for Applied Entomology and Parasitology, Faculty of Natural Sciences, Keele University, Keele, Staffordshire, ST55BG, UK.
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131
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Molina-Cruz A, Zilversmit MM, Neafsey DE, Hartl DL, Barillas-Mury C. Mosquito Vectors and the Globalization of Plasmodium falciparum Malaria. Annu Rev Genet 2016; 50:447-465. [PMID: 27732796 DOI: 10.1146/annurev-genet-120215-035211] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Plasmodium falciparum malaria remains a devastating public health problem. Recent discoveries have shed light on the origin and evolution of Plasmodium parasites and their interactions with their vertebrate and mosquito hosts. P. falciparum malaria originated in Africa from a single horizontal transfer between an infected gorilla and a human, and became global as the result of human migration. Today, P. falciparum malaria is transmitted worldwide by more than 70 different anopheline mosquito species. Recent studies indicate that the mosquito immune system can be a barrier to malaria transmission and that the P. falciparum Pfs47 gene allows the parasite to evade mosquito immune detection. Here, we review the origin and globalization of P. falciparum and integrate this history with analysis of the biology, evolution, and dispersal of the main mosquito vectors. This new perspective broadens our understanding of P. falciparum population structure and the dispersal of important parasite genetic traits.
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Affiliation(s)
- Alvaro Molina-Cruz
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland 20852;
| | - Martine M Zilversmit
- Richard Guilder Graduate School and Sackler Institute for Comparative Genomics, American Museum of Natural History, New York, NY 10024
| | - Daniel E Neafsey
- Genome Sequencing and Analysis Program, Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142
| | - Daniel L Hartl
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts 02138
| | - Carolina Barillas-Mury
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland 20852;
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132
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Holding T, Recker M. Maintenance of phenotypic diversity within a set of virulence encoding genes of the malaria parasite Plasmodium falciparum. J R Soc Interface 2016; 12:20150848. [PMID: 26674193 PMCID: PMC4707858 DOI: 10.1098/rsif.2015.0848] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Infection by the human malaria parasite Plasmodium falciparum results in a broad spectrum of clinical outcomes, ranging from severe and potentially life-threatening malaria to asymptomatic carriage. In a process of naturally acquired immunity, individuals living in malaria-endemic regions build up a level of clinical protection, which attenuates infection severity in an exposure-dependent manner. Underlying this shift in the immunoepidemiology as well as the observed range in malaria pathogenesis is the var multigene family and the phenotypic diversity embedded within. The var gene-encoded surface proteins Plasmodium falciparum erythrocyte membrane protein 1 mediate variant-specific binding of infected red blood cells to a diverse set of host receptors that has been linked to specific disease manifestations, including cerebral and pregnancy-associated malaria. Here, we show that cross-reactive immune responses, which minimize the within-host benefit of each additionally expressed gene during infection, can cause selection for maximum phenotypic diversity at the genome level. We further show that differential functional constraints on protein diversification stably maintain uneven ratios between phenotypic groups, in line with empirical observation. Our results thus suggest that the maintenance of phenotypic diversity within P. falciparum is driven by an evolutionary trade-off that optimizes between within-host parasite fitness and between-host selection pressure.
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Affiliation(s)
- Thomas Holding
- Centre for Mathematics and the Environment, University of Exeter, Penryn Campus, Penryn TR10 9EZ, UK
| | - Mario Recker
- Centre for Mathematics and the Environment, University of Exeter, Penryn Campus, Penryn TR10 9EZ, UK
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133
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Abstract
Malaria continues to impose a significant disease burden on low- and middle-income countries in the tropics. However, revolutionary progress over the last 3 years in nucleic acid sequencing, reverse genetics, and post-genome analyses has generated step changes in our understanding of malaria parasite (Plasmodium spp.) biology and its interactions with its host and vector. Driven by the availability of vast amounts of genome sequence data from Plasmodium species strains, relevant human populations of different ethnicities, and mosquito vectors, researchers can consider any biological component of the malarial process in isolation or in the interactive setting that is infection. In particular, considerable progress has been made in the area of population genomics, with Plasmodium falciparum serving as a highly relevant model. Such studies have demonstrated that genome evolution under strong selective pressure can be detected. These data, combined with reverse genetics, have enabled the identification of the region of the P. falciparum genome that is under selective pressure and the confirmation of the functionality of the mutations in the kelch13 gene that accompany resistance to the major frontline antimalarial, artemisinin. Furthermore, the central role of epigenetic regulation of gene expression and antigenic variation and developmental fate in P. falciparum is becoming ever clearer. This review summarizes recent exciting discoveries that genome technologies have enabled in malaria research and highlights some of their applications to healthcare. The knowledge gained will help to develop surveillance approaches for the emergence or spread of drug resistance and to identify new targets for the development of antimalarial drugs and perhaps vaccines.
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Affiliation(s)
- Sebastian Kirchner
- Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, College of Medical Veterinary & Life Sciences, University of Glasgow, Glasgow, G12 8TA, UK
| | - B Joanne Power
- Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, College of Medical Veterinary & Life Sciences, University of Glasgow, Glasgow, G12 8TA, UK
| | - Andrew P Waters
- Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, College of Medical Veterinary & Life Sciences, University of Glasgow, Glasgow, G12 8TA, UK.
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134
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Fraschka SAK, Henderson RWM, Bártfai R. H3.3 demarcates GC-rich coding and subtelomeric regions and serves as potential memory mark for virulence gene expression in Plasmodium falciparum. Sci Rep 2016; 6:31965. [PMID: 27555062 PMCID: PMC4995406 DOI: 10.1038/srep31965] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 07/26/2016] [Indexed: 12/16/2022] Open
Abstract
Histones, by packaging and organizing the DNA into chromatin, serve as essential building blocks for eukaryotic life. The basic structure of the chromatin is established by four canonical histones (H2A, H2B, H3 and H4), while histone variants are more commonly utilized to alter the properties of specific chromatin domains. H3.3, a variant of histone H3, was found to have diverse localization patterns and functions across species but has been rather poorly studied in protists. Here we present the first genome-wide analysis of H3.3 in the malaria-causing, apicomplexan parasite, P. falciparum, which revealed a complex occupancy profile consisting of conserved and parasite-specific features. In contrast to other histone variants, PfH3.3 primarily demarcates euchromatic coding and subtelomeric repetitive sequences. Stable occupancy of PfH3.3 in these regions is largely uncoupled from the transcriptional activity and appears to be primarily dependent on the GC-content of the underlying DNA. Importantly, PfH3.3 specifically marks the promoter region of an active and poised, but not inactive antigenic variation (var) gene, thereby potentially contributing to immune evasion. Collectively, our data suggest that PfH3.3, together with other histone variants, indexes the P. falciparum genome to functionally distinct domains and contribute to a key survival strategy of this deadly pathogen.
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Affiliation(s)
| | | | - Richárd Bártfai
- Department of Molecular Biology, Radboud University, Nijmegen, the Netherlands
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135
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Ayres Pereira M, Mandel Clausen T, Pehrson C, Mao Y, Resende M, Daugaard M, Riis Kristensen A, Spliid C, Mathiesen L, E. Knudsen L, Damm P, G. Theander T, R. Hansson S, A. Nielsen M, Salanti A. Placental Sequestration of Plasmodium falciparum Malaria Parasites Is Mediated by the Interaction Between VAR2CSA and Chondroitin Sulfate A on Syndecan-1. PLoS Pathog 2016; 12:e1005831. [PMID: 27556547 PMCID: PMC4996535 DOI: 10.1371/journal.ppat.1005831] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Accepted: 07/28/2016] [Indexed: 02/07/2023] Open
Abstract
During placental malaria, Plasmodium falciparum infected erythrocytes sequester in the placenta, causing health problems for both the mother and fetus. The specific adherence is mediated by the VAR2CSA protein, which binds to placental chondroitin sulfate (CS) on chondroitin sulfate proteoglycans (CSPGs) in the placental syncytium. However, the identity of the CSPG core protein and the cellular impact of the interaction have remain elusive. In this study we identified the specific CSPG core protein to which the CS is attached, and characterized its exact placental location. VAR2CSA pull-down experiments using placental extracts from whole placenta or syncytiotrophoblast microvillous cell membranes showed three distinct CSPGs available for VAR2CSA adherence. Further examination of these three CSPGs by immunofluorescence and proximity ligation assays showed that syndecan-1 is the main receptor for VAR2CSA mediated placental adherence. We further show that the commonly used placental choriocarcinoma cell line, BeWo, express a different set of proteoglycans than those present on placental syncytiotrophoblast and may not be the most biologically relevant model to study placental malaria. Syncytial fusion of the BeWo cells, triggered by forskolin treatment, caused an increased expression of placental CS-modified syndecan-1. In line with this, we show that rVAR2 binding to placental CS impairs syndecan-1-related Src signaling in forskolin treated BeWo cells, but not in untreated cells. Plasmodium falciparum is the most deadly malaria parasite, causing more than 500,000 deaths each year. The parasite infects the host’s red blood cells. In placental malaria infected red blood cells accumulate in placenta. The parasite protein VAR2CSA mediates this adherence, which causes complications for both mother and child. VAR2CSA binds a carbohydrate chain termed chondroitin sulfate (CS). CS is not a well-defined biochemical entity but constitute a family of oligosaccharides which each have unique sulfation patterns. The CS binding VAR2CSA is attached to proteoglycans expressed on the surface of placental cells. While much work has gone into understanding the nature of VAR2CSA and its interaction with placental CS, the protein to which the placental CS is attached is not known. To further the understanding of the molecular pathology of PM we characterized the CSPG receptor that the parasites adhere to by defining the exact proteoglycan that carries the placental CS. We further investigated the molecular and cellular consequences of VAR2CSA binding to the receptor. This work provides novel insights into the pathology of placental malaria and the nature of the parasite receptor. This may aid development of strategies to treat or prevent placental malaria.
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Affiliation(s)
- Marina Ayres Pereira
- Centre for Medical Parasitology, Department of Immunology and Microbiology, University of Copenhagen and Copenhagen University Hospital, Denmark
| | - Thomas Mandel Clausen
- Centre for Medical Parasitology, Department of Immunology and Microbiology, University of Copenhagen and Copenhagen University Hospital, Denmark
- Vancouver Prostate Centre, Vancouver, BC, Canada
- * E-mail: (TMC); (AS)
| | - Caroline Pehrson
- Centre for Medical Parasitology, Department of Immunology and Microbiology, University of Copenhagen and Copenhagen University Hospital, Denmark
| | - Yang Mao
- Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts, United States of America
- Copenhagen Center for Glycomics and Department of Cellular and Molecular Medicine, University of Copenhagen, Denmark
| | - Mafalda Resende
- Centre for Medical Parasitology, Department of Immunology and Microbiology, University of Copenhagen and Copenhagen University Hospital, Denmark
| | | | | | - Charlotte Spliid
- Centre for Medical Parasitology, Department of Immunology and Microbiology, University of Copenhagen and Copenhagen University Hospital, Denmark
| | - Line Mathiesen
- Section of Environmental Health, Department of Public Health, University of Copenhagen, Copenhagen, Denmark
| | - Lisbeth E. Knudsen
- Section of Environmental Health, Department of Public Health, University of Copenhagen, Copenhagen, Denmark
| | - Peter Damm
- Department of Obstetrics, Rigshospitalet, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Thor G. Theander
- Centre for Medical Parasitology, Department of Immunology and Microbiology, University of Copenhagen and Copenhagen University Hospital, Denmark
| | - Stefan R. Hansson
- Division of Obstetrics and Gynecology, Department of Clinical Sciences, Lund University Hospital, Lund University, Lund, Sweden
| | - Morten A. Nielsen
- Centre for Medical Parasitology, Department of Immunology and Microbiology, University of Copenhagen and Copenhagen University Hospital, Denmark
| | - Ali Salanti
- Centre for Medical Parasitology, Department of Immunology and Microbiology, University of Copenhagen and Copenhagen University Hospital, Denmark
- * E-mail: (TMC); (AS)
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136
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Infectivity of Plasmodium falciparum in Malaria-Naive Individuals Is Related to Knob Expression and Cytoadherence of the Parasite. Infect Immun 2016; 84:2689-96. [PMID: 27382019 DOI: 10.1128/iai.00414-16] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Accepted: 06/27/2016] [Indexed: 11/20/2022] Open
Abstract
Plasmodium falciparum is the most virulent human malaria parasite because of its ability to cytoadhere in the microvasculature. Nonhuman primate studies demonstrated relationships among knob expression, cytoadherence, and infectivity. This has not been examined in humans. Cultured clinical-grade P. falciparum parasites (NF54, 7G8, and 3D7B) and ex vivo-derived cell banks were characterized. Knob and knob-associated histidine-rich protein expression, CD36 adhesion, and antibody recognition of parasitized erythrocytes (PEs) were evaluated. Parasites from the cell banks were administered to malaria-naive human volunteers to explore infectivity. For the NF54 and 3D7B cell banks, blood was collected from the study participants for in vitro characterization. All parasites were infective in vivo However, infectivity of NF54 was dramatically reduced. In vitro characterization revealed that unlike other cell bank parasites, NF54 PEs lacked knobs and did not cytoadhere. Recognition of NF54 PEs by immune sera was observed, suggesting P. falciparum erythrocyte membrane protein 1 expression. Subsequent recovery of knob expression and CD36-mediated adhesion were observed in PEs derived from participants infected with NF54. Knobless cell bank parasites have a dramatic reduction in infectivity and the ability to adhere to CD36. Subsequent infection of malaria-naive volunteers restored knob expression and CD36-mediated cytoadherence, thereby showing that the human environment can modulate virulence.
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137
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Wang C, Adapa SR, Gibbons J, Sutton S, Jiang RHY. Punctuated chromatin states regulate Plasmodium falciparum antigenic variation at the intron and 2 kb upstream regions. BMC Genomics 2016; 17:652. [PMID: 27538502 PMCID: PMC4990864 DOI: 10.1186/s12864-016-3005-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Accepted: 08/10/2016] [Indexed: 11/27/2022] Open
Abstract
Background Understanding the regulation mechanism of var gene expression is crucial for explaining antigenic variation in Plasmodium falciparum. Recent work observed that while all var genes produce transcripts, only a few var genes exhibit high expression levels. However, the global regulation of var expression and the relationship between epigenetic and genetic control remains to be established. Result We have systematically reanalyzed the existing genomic data including chromatin configurations and gene expressions; and for the first time used robust statistical methods to show that the intron and 2 kb upstream regions of each endogenous var gene always maintain high chromatin accessibility, with high potential to bind transcription factors (TFs). The levels of transcripts for different var gene family members are associated with this chromatin accessibility. Any given var gene thus shows punctuated chromatin states throughout the asexual life cycle. This is demonstrated by three independent transcript datasets. Chromatin accessibility in the var intron and 2 kb upstream regions are also positively correlated with their GC content, suggesting the level of var genes silencing might be encoded in their intron sequences. Interestingly, both var intron and 2 kb upstream regions exhibit higher chromatin accessibility when the genes have relatively lower transcription levels, suggesting a punctuated repressive function for these regulatory elements. Conclusion By integrating and analyzing epigenomic, genomic and transcriptomic data, our work reveals a novel distal element in var control. We found dynamic modulations of specific epigenetic marks around the var intron and distal upstream regions are involved in the general var gene expression patterns in malarial antigenic variation. Electronic supplementary material The online version of this article (doi:10.1186/s12864-016-3005-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Chengqi Wang
- Department of Global Health (GH) & Center for Drug Discovery and Innovation (CDDI), College of Public Health, University of South Florida, Tampa, FL, 33612, USA
| | - Swamy R Adapa
- Department of Global Health (GH) & Center for Drug Discovery and Innovation (CDDI), College of Public Health, University of South Florida, Tampa, FL, 33612, USA
| | - Justin Gibbons
- Department of Global Health (GH) & Center for Drug Discovery and Innovation (CDDI), College of Public Health, University of South Florida, Tampa, FL, 33612, USA.,Department of Molecular Medicine, University of South Florida, Tampa, FL, 33612, USA
| | - Stephen Sutton
- Department of Global Health (GH) & Center for Drug Discovery and Innovation (CDDI), College of Public Health, University of South Florida, Tampa, FL, 33612, USA
| | - Rays H Y Jiang
- Department of Global Health (GH) & Center for Drug Discovery and Innovation (CDDI), College of Public Health, University of South Florida, Tampa, FL, 33612, USA.
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138
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Quintana MDP, Angeletti D, Moll K, Chen Q, Wahlgren M. Phagocytosis-inducing antibodies to Plasmodium falciparum upon immunization with a recombinant PfEMP1 NTS-DBL1α domain. Malar J 2016; 15:416. [PMID: 27531359 PMCID: PMC4987995 DOI: 10.1186/s12936-016-1459-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Accepted: 07/29/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Individuals living in endemic areas gradually acquire natural immunity to clinical malaria, largely dependent on antibodies against parasite antigens. There are many studies indicating that the variant antigen PfEMP1 at the surface of the parasitized red blood cell (pRBC) is one of the major targets of the immune response. It is believed that antibodies against PfEMP1 confer protection by blocking sequestration (rosetting and cytoadherence), inducing antibody-dependent cellular-inhibitory effect and opsonizing pRBCs for phagocytosis. METHODS A recombinant NTS-DBL1α domain from a rosette-mediating PfEMP1 was expressed in Escherichia coli. The resulting protein was purified and used for immunization to generate polyclonal (goat) and monoclonal (mouse) antibodies. The antibodies' ability to opsonize and induce phagocytosis in vitro was tested and contrasted with the presence of opsonizing antibodies naturally acquired during Plasmodium falciparum infection. RESULTS All antibodies recognized the recombinant antigen and the surface of live pRBCs, however, their capacity to opsonize the pRBCs for phagocytosis varied. The monoclonal antibodies isotyped as IgG2b did not induce phagocytosis, while those isotyped as IgG2a were in general very effective, inducing phagocytosis with similar levels as those naturally acquired during P. falciparum infection. These monoclonal antibodies displayed different patterns, some of them showing a concentration-dependent activity while others showed a prozone-like effect. The goat polyclonal antibodies were not able to induce phagocytosis. CONCLUSION Immunization with an NTS-DBL1-α domain of PfEMP1 generates antibodies that not only have a biological role in rosette disruption but also effectively induce opsonization for phagocytosis of pRBCs with similar activity to naturally acquired antibodies from immune individuals living in a malaria endemic area. Some of the antibodies with high opsonizing activity were not able to disrupt rosettes, indicating that epitopes of the NTS-DBL1-α other than those involved in rosetting are exposed on the pRBC surface and are able to induce functional antibodies. The ability to induce phagocytosis largely depended on the antibody isotype and on the ability to recognize the surface of the pRBC regardless of the rosette-disrupting capacity.
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Affiliation(s)
- Maria Del Pilar Quintana
- Department of Microbiology, Tumor and Cell Biology (MTC), Karolinska Institutet, Stockholm, Sweden.,Escuela de Medicina y Ciencias de la Salud, Facultad de Ciencias Naturales y Matemáticas, Universidad del Rosario, Bogotá, Colombia
| | - Davide Angeletti
- Department of Microbiology, Tumor and Cell Biology (MTC), Karolinska Institutet, Stockholm, Sweden
| | - Kirsten Moll
- Department of Microbiology, Tumor and Cell Biology (MTC), Karolinska Institutet, Stockholm, Sweden
| | - Qijun Chen
- Department of Microbiology, Tumor and Cell Biology (MTC), Karolinska Institutet, Stockholm, Sweden.,Key Laboratory of Zoonosis, Jilin University, Changchun, People's Republic of China.,Institute of Pathogen Biology, Chinese Academy of Medical Sciences, Beijing, People's Republic of China
| | - Mats Wahlgren
- Department of Microbiology, Tumor and Cell Biology (MTC), Karolinska Institutet, Stockholm, Sweden.
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139
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Sharma D, Soni R, Patel S, Joshi D, Bhatt TK. In-silico studies on DegP protein of Plasmodium falciparum in search of anti-malarials. J Mol Model 2016; 22:201. [PMID: 27491850 DOI: 10.1007/s00894-016-3064-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Accepted: 07/03/2016] [Indexed: 10/21/2022]
Abstract
Despite encouraging progress over the past decade, malaria caused by the Plasmodium parasite continues to pose an enormous disease burden and is one of the major global health problems. The extreme challenge in malaria management is the resistance of parasites to traditional monochemotherapies like chloroquine and sulfadoxine-pyrimethamine. No vaccine is yet in sight, and the foregoing effective drugs are also losing ground against the disease due to the resistivity of parasites. New antimalarials with novel mechanisms of action are needed to circumvent existing or emerging drug resistance. DegP protein, secretory in nature has been shown to be involved in regulation of thermo-oxidative stress generated during asexual life cycle of Plasmodium, probably required for survival of parasite in host. Considering the significance of protein, in this study, we have generated a three-dimensional structure of PfDegP followed by validation of the modeled structure using several tools like RAMPAGE, ERRAT, and others. We also performed an in-silico screening of small molecule database against PfDegP using Glide. Furthermore, molecular dynamics simulation of protein and protein-ligand complex was carried out using GROMACS. This study substantiated potential drug-like molecules and provides the scope for development of novel antimalarial drugs.
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Affiliation(s)
- Drista Sharma
- Department of Biotechnology, Central University of Rajasthan, NH-8, Bandarsindri, Rajasthan, India, 305801
| | - Rani Soni
- Department of Biotechnology, Central University of Rajasthan, NH-8, Bandarsindri, Rajasthan, India, 305801
| | - Sachin Patel
- Department of Biotechnology, Central University of Rajasthan, NH-8, Bandarsindri, Rajasthan, India, 305801
| | - Deepti Joshi
- Department of Biotechnology, Central University of Rajasthan, NH-8, Bandarsindri, Rajasthan, India, 305801
| | - Tarun Kumar Bhatt
- Department of Biotechnology, Central University of Rajasthan, NH-8, Bandarsindri, Rajasthan, India, 305801.
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140
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Jespersen JS, Wang CW, Mkumbaye SI, Minja DT, Petersen B, Turner L, Petersen JE, Lusingu JP, Theander TG, Lavstsen T. Plasmodium falciparum var genes expressed in children with severe malaria encode CIDRα1 domains. EMBO Mol Med 2016; 8:839-50. [PMID: 27354391 PMCID: PMC4967939 DOI: 10.15252/emmm.201606188] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Most severe Plasmodium falciparum infections are experienced by young children. Severe symptoms are precipitated by vascular sequestration of parasites expressing a particular subset of the polymorphic P. falciparum erythrocyte membrane protein 1 (PfEMP1) adhesion molecules. Parasites binding human endothelial protein C receptor (EPCR) through the CIDRα1 domain of certain PfEMP1 were recently associated with severe malaria in children. However, it has remained unclear to which extend the EPCR‐binding CIDRα1 domains epitomize PfEMP1 expressed in severe malaria. Here, we characterized the near full‐length transcripts dominating the var transcriptome in children with severe malaria and found that the only common feature of the encoded PfEMP1 was CIDRα1 domains. Such genes were highly and dominantly expressed in both children with severe malarial anaemia and cerebral malaria. These observations support the hypothesis that the CIDRα1‐EPCR interaction is key to the pathogenesis of severe malaria and strengthen the rationale for pursuing a vaccine or adjunctive treatment aiming at inhibiting or reducing the damaging effects of this interaction.
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Affiliation(s)
- Jakob S Jespersen
- Centre for Medical Parasitology, Department of Immunology & Microbiology, University of Copenhagen, Copenhagen, Denmark Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark
| | - Christian W Wang
- Centre for Medical Parasitology, Department of Immunology & Microbiology, University of Copenhagen, Copenhagen, Denmark Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark
| | - Sixbert I Mkumbaye
- Kilimanjaro Christian Medical University College, Kilimanjaro Clinical Research Institute, Moshi, Tanzania
| | - Daniel Tr Minja
- National Institute for Medical Research, Tanga Research Centre, Tanga, Tanzania
| | - Bent Petersen
- Centre for Biological Sequence Analysis, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Louise Turner
- Centre for Medical Parasitology, Department of Immunology & Microbiology, University of Copenhagen, Copenhagen, Denmark Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark
| | - Jens Ev Petersen
- Centre for Medical Parasitology, Department of Immunology & Microbiology, University of Copenhagen, Copenhagen, Denmark Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark
| | - John Pa Lusingu
- Centre for Medical Parasitology, Department of Immunology & Microbiology, University of Copenhagen, Copenhagen, Denmark Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark National Institute for Medical Research, Tanga Research Centre, Tanga, Tanzania
| | - Thor G Theander
- Centre for Medical Parasitology, Department of Immunology & Microbiology, University of Copenhagen, Copenhagen, Denmark Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark
| | - Thomas Lavstsen
- Centre for Medical Parasitology, Department of Immunology & Microbiology, University of Copenhagen, Copenhagen, Denmark Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark
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141
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Molecular dissection of placental malaria protein VAR2CSA interaction with a chemo-enzymatically synthesized chondroitin sulfate library. Glycoconj J 2016; 33:985-994. [DOI: 10.1007/s10719-016-9685-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Revised: 05/20/2016] [Accepted: 05/24/2016] [Indexed: 12/27/2022]
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142
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Dimonte S, Bruske EI, Hass J, Supan C, Salazar CL, Held J, Tschan S, Esen M, Flötenmeyer M, Koch I, Berger J, Bachmann A, Sim BKL, Hoffman SL, Kremsner PG, Mordmüller B, Frank M. Sporozoite Route of Infection Influences In Vitro var Gene Transcription of Plasmodium falciparum Parasites From Controlled Human Infections. J Infect Dis 2016; 214:884-94. [PMID: 27279526 DOI: 10.1093/infdis/jiw225] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Accepted: 05/19/2016] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Antigenic variation in Plasmodium falciparum is mediated by the multicopy var gene family. Each parasite possesses about 60 var genes, and switching between active var loci results in antigenic variation. In the current study, the effect of mosquito and host passage on in vitro var gene transcription was investigated. METHODS Thirty malaria-naive individuals were inoculated by intradermal or intravenous injection with cryopreserved, isogenic NF54 P. falciparum sporozoites (PfSPZ) generated from 1 premosquito culture. Microscopic parasitemia developed in 22 individuals, and 21 in vitro cultures were established. The var gene transcript levels were determined in early and late postpatient cultures and in the premosquito culture. RESULTS At the early time point, all cultures preferentially transcribed 8 subtelomeric var genes. Intradermal infections had higher var gene transcript levels than intravenous infections and a significantly longer intrahost replication time (P = .03). At the late time point, 9 subtelomeric and 8 central var genes were transcribed at the same levels in almost all cultures. Premosquito and late postpatient cultures transcribed the same subtelomeric and central var genes, except for var2csa CONCLUSIONS The duration of intrahost replication influences in vitro var gene transcript patterns. Differences between premosquito and postpatient cultures decrease with prolonged in vitro growth.
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Affiliation(s)
- Sandra Dimonte
- Institute of Tropical Medicine University of Tübingen and German Center for Infection Research, Partner Site Tübingen
| | - Ellen I Bruske
- Institute of Tropical Medicine University of Tübingen and German Center for Infection Research, Partner Site Tübingen
| | - Johanna Hass
- Institute of Tropical Medicine University of Tübingen and German Center for Infection Research, Partner Site Tübingen
| | - Christian Supan
- Institute of Tropical Medicine University of Tübingen and German Center for Infection Research, Partner Site Tübingen
| | - Carmen L Salazar
- Institute of Tropical Medicine University of Tübingen and German Center for Infection Research, Partner Site Tübingen
| | - Jana Held
- Institute of Tropical Medicine University of Tübingen and German Center for Infection Research, Partner Site Tübingen
| | - Serena Tschan
- Institute of Tropical Medicine University of Tübingen and German Center for Infection Research, Partner Site Tübingen
| | - Meral Esen
- Institute of Tropical Medicine University of Tübingen and German Center for Infection Research, Partner Site Tübingen
| | | | - Iris Koch
- Max Planck Institute for Developmental Biology, Tübingen
| | - Jürgen Berger
- Max Planck Institute for Developmental Biology, Tübingen
| | - Anna Bachmann
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | | | | | - Peter G Kremsner
- Institute of Tropical Medicine University of Tübingen and German Center for Infection Research, Partner Site Tübingen Centre de Recherches Médicales de Lambaréné (CERMEL), Fondation Internationale de l'Hôpital Albert Schweitzer, Lambaréné, Gabon
| | - Benjamin Mordmüller
- Institute of Tropical Medicine University of Tübingen and German Center for Infection Research, Partner Site Tübingen
| | - Matthias Frank
- Institute of Tropical Medicine University of Tübingen and German Center for Infection Research, Partner Site Tübingen
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143
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Przyborski JM, Nyboer B, Lanzer M. Ticket to ride: export of proteins to the Plasmodium falciparum-infected erythrocyte. Mol Microbiol 2016; 101:1-11. [PMID: 26996123 DOI: 10.1111/mmi.13380] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/17/2016] [Indexed: 12/28/2022]
Abstract
The malaria parasite Plasmodium falciparum exports numerous proteins to its chosen host cell, the mature human erythrocyte. Many of these proteins are important for parasite survival. To reach the host cell, parasites must cross multiple membrane barriers and then furthermore be targeted to their correct sub-cellular localisation. This novel transport pathway has received much research attention in the past decades, especially as many of the mechanisms are expected to be parasite-specific and thus potential targets for drug development. In this article we summarize some of the most recent advances in this field, and highlight areas in which further research is needed.
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Affiliation(s)
- Jude M Przyborski
- Parasitology, Faculty of Biology, Philipps University Marburg, Karl von Frisch Strasse 8, 35043, Marburg, Germany
| | - Britta Nyboer
- Center of Infectious Diseases, Parasitology, Heidelberg University, Im Neuenheimer Feld 324, 69120, Heidelberg, Germany
| | - Michael Lanzer
- Center of Infectious Diseases, Parasitology, Heidelberg University, Im Neuenheimer Feld 324, 69120, Heidelberg, Germany
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144
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Severe adult malaria is associated with specific PfEMP1 adhesion types and high parasite biomass. Proc Natl Acad Sci U S A 2016; 113:E3270-9. [PMID: 27185931 DOI: 10.1073/pnas.1524294113] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The interplay between cellular and molecular determinants that lead to severe malaria in adults is unexplored. Here, we analyzed parasite virulence factors in an infected adult population in India and investigated whether severe malaria isolates impair endothelial protein C receptor (EPCR), a protein involved in coagulation and endothelial barrier permeability. Severe malaria isolates overexpressed specific members of the Plasmodium falciparum var gene/PfEMP1 (P. falciparum erythrocyte membrane protein 1) family that bind EPCR, including DC8 var genes that have previously been linked to severe pediatric malaria. Machine learning analysis revealed that DC6- and DC8-encoding var transcripts in combination with high parasite biomass were the strongest indicators of patient hospitalization and disease severity. We found that DC8 CIDRα1 domains from severe malaria isolates had substantial differences in EPCR binding affinity and blockade activity for its ligand activated protein C. Additionally, even a low level of inhibition exhibited by domains from two cerebral malaria isolates was sufficient to interfere with activated protein C-barrier protective activities in human brain endothelial cells. Our findings demonstrate an interplay between parasite biomass and specific PfEMP1 adhesion types in the development of adult severe malaria, and indicate that low impairment of EPCR function may contribute to parasite virulence.
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145
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Duffy MF, Noviyanti R, Tsuboi T, Feng ZP, Trianty L, Sebayang BF, Takashima E, Sumardy F, Lampah DA, Turner L, Lavstsen T, Fowkes FJI, Siba P, Rogerson SJ, Theander TG, Marfurt J, Price RN, Anstey NM, Brown GV, Papenfuss AT. Differences in PfEMP1s recognized by antibodies from patients with uncomplicated or severe malaria. Malar J 2016; 15:258. [PMID: 27149991 PMCID: PMC4858840 DOI: 10.1186/s12936-016-1296-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Accepted: 04/15/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) variants are encoded by var genes and mediate pathogenic cytoadhesion and antigenic variation in malaria. PfEMP1s can be broadly divided into three principal groups (A, B and C) and they contain conserved arrangements of functional domains called domain cassettes. Despite their tremendous diversity there is compelling evidence that a restricted subset of PfEMP1s is expressed in severe disease. In this study antibodies from patients with severe and uncomplicated malaria were compared for differences in reactivity with a range of PfEMP1s to determine whether antibodies to particular PfEMP1 domains were associated with severe or uncomplicated malaria. METHODS Parts of expressed var genes in a severe malaria patient were identified by RNAseq and several of these partial PfEMP1 domains were expressed together with others from laboratory isolates. Antibodies from Papuan patients to these parts of multiple PfEMP1 proteins were measured. RESULTS Patients with uncomplicated malaria were more likely to have antibodies that recognized PfEMP1 of Group C type and recognized a broader repertoire of group A and B PfEMP1s than patients with severe malaria. CONCLUSION These data suggest that exposure to a broad range of group A and B PfEMP1s is associated with protection from severe disease in Papua, Indonesia.
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Affiliation(s)
- Michael F. Duffy
- />Department of Medicine, Royal Melbourne Hospital, The University of Melbourne, The Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria Australia
| | - Rintis Noviyanti
- />The Eijkman Institute for Molecular Biology, Jakarta, Indonesia
| | - Takafumi Tsuboi
- />Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Ehime Japan
| | - Zhi-Ping Feng
- />Bioinformatics Division, The Walter & Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- />Department of Medical Biology, University of Melbourne, Parkville, Victoria Australia
| | - Leily Trianty
- />The Eijkman Institute for Molecular Biology, Jakarta, Indonesia
| | - Boni F. Sebayang
- />The Eijkman Institute for Molecular Biology, Jakarta, Indonesia
| | - Eizo Takashima
- />Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Ehime Japan
| | - Fransisca Sumardy
- />Department of Medicine, Royal Melbourne Hospital, The University of Melbourne, The Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria Australia
| | - Daniel A. Lampah
- />Timika Malaria Research Program, Papuan Health and Community Development Foundation, Timika, Papua Indonesia
| | - Louise Turner
- />Centre for Medical Parasitology, University of Copenhagen, Copenhagen, Denmark
| | - Thomas Lavstsen
- />Centre for Medical Parasitology, University of Copenhagen, Copenhagen, Denmark
| | | | - Peter Siba
- />The Papua New Guinea Institute for Medical Research, Madang, Papua New Guinea
| | - Stephen J. Rogerson
- />Department of Medicine, Royal Melbourne Hospital, The University of Melbourne, The Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria Australia
| | - Thor G. Theander
- />Centre for Medical Parasitology, University of Copenhagen, Copenhagen, Denmark
| | - Jutta Marfurt
- />Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, NT Australia
| | - Ric N. Price
- />Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, NT Australia
- />Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Nicholas M. Anstey
- />Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, NT Australia
| | - Graham V. Brown
- />The Nossal Institute for Global Health, The University of Melbourne, Parkville, Victoria Australia
| | - Anthony T. Papenfuss
- />Bioinformatics Division, The Walter & Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- />Department of Medical Biology, University of Melbourne, Parkville, Victoria Australia
- />Peter MacCallum Cancer Centre, East Melbourne, Victoria, Australia
- />Sir Peter MacCallum Department of Oncology, University of Melbourne, Melbourne, Victoria Australia
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146
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Arnot DE, Jensen ATR. Antigenic Variation and the Genetics and Epigenetics of the PfEMP1 Erythrocyte Surface Antigens in Plasmodium falciparum Malaria. ADVANCES IN APPLIED MICROBIOLOGY 2016; 74:77-96. [PMID: 21459194 DOI: 10.1016/b978-0-12-387022-3.00007-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
How immunity to malaria develops remains one of the great unresolved issues in bio-medicine and resolution of its various paradoxes is likely to be the key to developing effective malaria vaccines. The basic epidemiological observations are; under conditions of intense natural transmission, humans do become immune to P. falciparum malaria, but this is a slow process requiring multiple disease episodes which many, particularly young children, do not survive. Adult survivors are immune to the symptoms of malaria, and unless pregnant, can control the growth of most or all new inoculations. Sterile immunity is not achieved and chronic parasitization of apparently healthy adults is the norm. In this article, we analyse the best understood malaria "antigenic variation" system, that based on Plasmodium falciparum's PfEMP1-type cytoadhesion antigens, and critically review recent literature on the function and control of this multi-gene family of parasite variable surface antigens.
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Affiliation(s)
- David E Arnot
- Centre for Medical Parasitology, Department of International Health, Immunology and Microbiology, Faculty of Health Sciences, University of Copenhagen, CSS Oester Farimagsgade 5, Copenhagen K, Denmark; Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), CSS Oester Farimagsgade 5, Copenhagen K, Denmark; Institute of Immunology and Infection Research, School of Biology, University of Edinburgh, Edinburgh, Scotland, United Kingdom
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147
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Mosquito Passage Dramatically Changes var Gene Expression in Controlled Human Plasmodium falciparum Infections. PLoS Pathog 2016; 12:e1005538. [PMID: 27070311 PMCID: PMC4829248 DOI: 10.1371/journal.ppat.1005538] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 03/10/2016] [Indexed: 11/19/2022] Open
Abstract
Virulence of the most deadly malaria parasite Plasmodium falciparum is linked to the variant surface antigen PfEMP1, which is encoded by about 60 var genes per parasite genome. Although the expression of particular variants has been associated with different clinical outcomes, little is known about var gene expression at the onset of infection. By analyzing controlled human malaria infections via quantitative real-time PCR, we show that parasite populations from 18 volunteers expressed virtually identical transcript patterns that were dominated by the subtelomeric var gene group B and, to a lesser extent, group A. Furthermore, major changes in composition and frequency of var gene transcripts were detected between the parental parasite culture that was used to infect mosquitoes and Plasmodia recovered from infected volunteers, suggesting that P. falciparum resets its var gene expression during mosquito passage and starts with the broad expression of a specific subset of var genes when entering the human blood phase.
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148
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Hora R, Kapoor P, Thind KK, Mishra PC. Cerebral malaria--clinical manifestations and pathogenesis. Metab Brain Dis 2016; 31:225-37. [PMID: 26746434 DOI: 10.1007/s11011-015-9787-5] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 12/22/2015] [Indexed: 01/28/2023]
Abstract
One of the most common central nervous system diseases in tropical countries is cerebral malaria (CM). Malaria is a common protozoan infection that is responsible for enormous worldwide mortality and economic burden on the society. Episodes of Plasmodium falciparum (Pf) caused CM may be lethal, while survivors are likely to suffer from persistent debilitating neurological deficits, especially common in children. In this review article, we have summarized the various symptoms and manifestations of CM in children and adults, and entailed the molecular basis of the disease. We have also emphasized how pathogenesis of the disease is effected by the parasite and host responses including blood brain barrier (BBB) disruption, endothelial cell activation and apoptosis, nitric oxide bioavailability, platelet activation and apoptosis, and neuroinflammation. Based on a few recent studies carried out in experimental mouse malaria models, we propose a basis for the neurological deficits and sequelae observed in human cerebral malaria, and summarize how existing drugs may improve prognosis in affected individuals.
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Affiliation(s)
- Rachna Hora
- Department of Molecular Biology and Biochemistry, Guru Nanak Dev University, Amritsar, 143005, India.
| | - Payal Kapoor
- Department of Molecular Biology and Biochemistry, Guru Nanak Dev University, Amritsar, 143005, India
| | - Kirandeep Kaur Thind
- Department of Molecular Biology and Biochemistry, Guru Nanak Dev University, Amritsar, 143005, India
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149
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Role of the ER and Golgi in protein export by Apicomplexa. Curr Opin Cell Biol 2016; 41:18-24. [PMID: 27019341 DOI: 10.1016/j.ceb.2016.03.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Revised: 03/06/2016] [Accepted: 03/07/2016] [Indexed: 12/31/2022]
Abstract
Apicomplexan parasites cause diseases of medical and agricultural importance linked to dramatic changes they impart upon infected host cells. Following invasion, the malaria parasite Plasmodium falciparum renovates the host erythrocyte using mechanisms previously believed to be malaria-specific. This involves proteolytic cleavage of effectors in the endoplasmic reticulum that licences proteins for translocation into the host cell. Recently, it was demonstrated that the related parasite Toxoplasma gondii, responsible for disease in immunocompromised individuals and congenital birth defects, has an analogous pathway with some differences, including proteolytic processing in the Golgi. Here we review the similarities and distinctions in export mechanisms between these and other Apicomplexan parasites to reconcile how this group of pathogens modify their host cells to survive and proliferate.
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150
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Recombination and Diversification of the Variant Antigen Encoding Genes in the Malaria Parasite Plasmodium falciparum. Microbiol Spectr 2016; 2. [PMID: 26104446 DOI: 10.1128/microbiolspec.mdna3-0022-2014] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The most severe form of human malaria is caused by the protozoan parasite Plasmodium falciparum. These parasites invade and replicate within the circulating red blood cells of infected individuals leading to numerous disease manifestations, including severe anemia, altered circulation, and tissue inflammation. Malaria parasites are also known for their ability to maintain a chronic infection through antigenic variation, the ability to systematically alter the antigens displayed on the surface of infected cells and thereby avoid clearance by the host's antibody response. The genome of P. falciparum includes several large, multicopy gene families that encode highly variable forms of the surface proteins that are the targets of host immunity. Alterations in expression of genes within these families are responsible for antigenic variation. This process requires the continuous generation of new antigenic variants within these gene families, and studies have shown that new variants arise through extensive recombination and gene conversion events between family members. Malaria parasites possess an unusual complement of DNA repair pathways, thus the study of recombination between variant antigen encoding genes provides a unique view into the evolution of mobile DNA in an organism distantly related to the more closely studied model eukaryotes.
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