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Joof F, Hu R, Saidi A, Seydel KB, Cohee LM, Zheng Y, Smith JD. Plasma from older children in Malawi inhibits Plasmodium falciparum binding in 3D brain microvessels. J Infect Dis 2024:jiae315. [PMID: 38875153 DOI: 10.1093/infdis/jiae315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Revised: 05/02/2024] [Accepted: 06/12/2024] [Indexed: 06/16/2024] Open
Abstract
A hallmark of cerebral malaria is sequestration of Plasmodium falciparum-infected erythrocytes (IEs) in the brain microcirculation. Antibodies contribute to malaria immunity, but it remains unclear whether functional antibodies targeting parasite-expressed ligand can block cytoadhesion in the brain. Here, we screened the plasma of older children and young adults in Malawi to characterize the antibody response against the P. falciparum-IE surface and used a bioengineered 3D human brain microvessel model incorporating variable flow dynamics to measure adhesion blocking responses. We found a strong correlation between surface antibody reactivity by flow cytometry and reduced P. falciparum-IE binding in 3D microvessels. Moreover, there was a threshold of surface antibody reactivity necessary to achieve robust inhibitory activity. Our findings provide evidence of the acquisition of adhesion blocking antibodies against cerebral binding variants in people exposed to stable P. falciparum transmission and suggest the quality of the inhibitory response can be influenced by flow dynamics.
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Affiliation(s)
- Fatou Joof
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA USA
| | - Ruoqian Hu
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Alex Saidi
- Blantyre Malaria Project, Kamuzu University of Health Sciences, Blantyre, Malawi
| | - Karl B Seydel
- Blantyre Malaria Project, Kamuzu University of Health Sciences, Blantyre, Malawi
- Department of Osteopathic Medical Specialties, College of Osteopathic Medicine, Michigan State University, East Lansing, Michigan, USA
| | - Lauren M Cohee
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Ying Zheng
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Joseph D Smith
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA USA
- Department of Pediatrics, School of Medicine, University of Washington, Seattle, WA, USA
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2
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Chaudhry S, Kojom Foko LP, Narang G, Hawadak J, Arya A, Pande V, Singh V. Genotyping var Gene DBL1α Domain of Severe and Non-severe Plasmodium falciparum Patients. Indian J Microbiol 2024; 64:583-592. [PMID: 39011004 PMCID: PMC11246362 DOI: 10.1007/s12088-024-01200-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Accepted: 01/05/2024] [Indexed: 07/17/2024] Open
Abstract
This study analysed the genetic diversity of DBL1α domain of Plasmodium falciparum var gene in severe and non-severe malaria patients from Delhi and Mewat in Northern India. After confirming P. falciparum infection, samples were cloned and the var gene DBL1α domain was sequenced. Out of 377 cloned DBL sequences, 194 were from severe samples and 183 from non-severe samples. Proportion of DBL1α sequences belonging to groups 1, 4 and 5 were significantly higher in severe isolates as compared to non-severe isolates-group 1 (4.1% vs 1.09%, P = 0.0333), group 4 (69.58% vs 74.31%, P < 0.0001), and group 5 (19.58% vs 10.38%, P < 0.0001). Conversely, higher proportion of group 2 was observed in non-severe isolates (0% vs 3.82%, P = 0.0350). Highest diversity was seen in PoLV4 motif of severe and non-severe isolates and like other DBL1α sequences reported from several geographical areas (Africa, Americas, Asia, and Oceania). A total of 247 DBL1α domain haplotypes were found in this study where 139 (56.27%) haplotypes are novel and not reported from India till date. These findings could aid in developing effective malaria interventions, including vaccine and drug targets, by understanding the existing antigenic diversity and vulnerabilities in the parasite's genetic makeup. Supplementary Information The online version contains supplementary material available at 10.1007/s12088-024-01200-1.
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Affiliation(s)
- Shewta Chaudhry
- Cell Biology Laboratory and Malaria Parasite Bank, ICMR-National Institute of Malaria Research, New Delhi, India
- Department of Biotechnology, Kumaun University, Nainital, Uttarakhand 263001 India
| | - Loick Pradel Kojom Foko
- Cell Biology Laboratory and Malaria Parasite Bank, ICMR-National Institute of Malaria Research, New Delhi, India
- Department of Biotechnology, Kumaun University, Nainital, Uttarakhand 263001 India
| | - Geetika Narang
- Cell Biology Laboratory and Malaria Parasite Bank, ICMR-National Institute of Malaria Research, New Delhi, India
| | - Joseph Hawadak
- Cell Biology Laboratory and Malaria Parasite Bank, ICMR-National Institute of Malaria Research, New Delhi, India
- Department of Biotechnology, Kumaun University, Nainital, Uttarakhand 263001 India
| | - Aditi Arya
- Cell Biology Laboratory and Malaria Parasite Bank, ICMR-National Institute of Malaria Research, New Delhi, India
- Department of Biotechnology, Kumaun University, Nainital, Uttarakhand 263001 India
| | - Veena Pande
- Department of Biotechnology, Kumaun University, Nainital, Uttarakhand 263001 India
| | - Vineeta Singh
- Cell Biology Laboratory and Malaria Parasite Bank, ICMR-National Institute of Malaria Research, New Delhi, India
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3
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Zhan Q, Tiedje KE, Day KP, Pascual M. From multiplicity of infection to force of infection for sparsely sampled Plasmodium falciparum populations at high transmission. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.02.12.24302148. [PMID: 38853963 PMCID: PMC11160831 DOI: 10.1101/2024.02.12.24302148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2024]
Abstract
High multiplicity of infection or MOI, the number of genetically distinct parasite strains co-infecting a single human host, characterizes infectious diseases including falciparum malaria at high transmission. It accompanies high asymptomatic Plasmodium falciparum prevalence despite high exposure, creating a large transmission reservoir challenging intervention. High MOI and asymptomatic prevalence are enabled by immune evasion of the parasite achieved via vast antigenic diversity. Force of infection or FOI, the number of new infections acquired by an individual host over a given time interval, is the dynamic sister quantity of MOI, and a key epidemiological parameter for monitoring the impact of antimalarial interventions and assessing vaccine or drug efficacy in clinical trials. FOI remains difficult, expensive, and labor-intensive to accurately measure, especially in high-transmission regions, whether directly via cohort studies or indirectly via the fitting of epidemiological models to repeated cross-sectional surveys. We propose here the application of queuing theory to obtain FOI on the basis of MOI, in the form of either a two-moment approximation method or Little's law. We illustrate these methods with MOI estimates obtained under sparse sampling schemes with the recently proposed " v a r coding" method, based on sequences of the v a r multigene family encoding for the major variant surface antigen of the blood stage of malaria infection. The methods are evaluated with simulation output from a stochastic agent-based model, and are applied to an interrupted time-series study from Bongo District in northern Ghana before and immediately after a three-round transient indoor residual spraying (IRS) intervention. We incorporate into the sampling of the simulation output, limitations representative of those encountered in the collection of field data, including under-sampling of v a r genes, missing data, and usage of antimalarial drug treatment. We address these limitations in MOI estimates with a Bayesian framework and an imputation bootstrap approach. We demonstrate that both proposed methods give good and consistent FOI estimates across various simulated scenarios. Their application to the field surveys shows a pronounced reduction in annual FOI during intervention, of more than 70%. The proposed approach should be applicable to the many geographical locations where cohort or cross-sectional studies with regular and frequent sampling are lacking but single-time-point surveys under sparse sampling schemes are available, and for MOI estimates obtained in different ways. They should also be relevant to other pathogens of humans, wildlife and livestock whose immune evasion strategies are based on large antigenic variation resulting in high multiplicity of infection.
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Affiliation(s)
- Qi Zhan
- Committee on Genetics, Genomics and Systems Biology, The University of Chicago, Chicago, IL, USA
| | - Kathryn E. Tiedje
- Department of Microbiology and Immunology, Bio21 Institute and Peter Doherty Institute, The University of Melbourne, Melbourne, Australia
| | - Karen P. Day
- Department of Microbiology and Immunology, Bio21 Institute and Peter Doherty Institute, The University of Melbourne, Melbourne, Australia
| | - Mercedes Pascual
- Department of Biology, New York University, New York, NY, USA
- Department of Environmental Studies, New York University, New York, NY, USA
- Santa Fe Institute, Santa Fe, NM, USA
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4
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Zhan Q, He Q, Tiedje KE, Day KP, Pascual M. Hyper-diverse antigenic variation and resilience to transmission-reducing intervention in falciparum malaria. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.02.01.24301818. [PMID: 38370729 PMCID: PMC10871444 DOI: 10.1101/2024.02.01.24301818] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/20/2024]
Abstract
Intervention against falciparum malaria in high transmission regions remains challenging, with relaxation of control efforts typically followed by rapid resurgence. Resilience to intervention co-occurs with incomplete immunity, whereby children eventually become protected from severe disease but not infection and a large transmission reservoir results from high asymptomatic prevalence across all ages. Incomplete immunity relates to the vast antigenic variation of the parasite, with the major surface antigen of the blood stage of infection encoded by the multigene family known as var. Recent deep sampling of var sequences from individual isolates in northern Ghana showed that parasite population structure exhibited persistent features of high-transmission regions despite the considerable decrease in prevalence during transient intervention with indoor residual spraying (IRS). We ask whether despite such apparent limited impact, the transmission system had been brought close to a transition in both prevalence and resurgence ability. With a stochastic agent-based model, we investigate the existence of such a transition to pre-elimination with intervention intensity, and of molecular indicators informative of its approach. We show that resurgence ability decreases sharply and nonlinearly across a narrow region of intervention intensities in model simulations, and identify informative molecular indicators based on var gene sequences. Their application to the survey data indicates that the transmission system in northern Ghana was brought close to transition by IRS. These results suggest that sustaining and intensifying intervention would have pushed malaria dynamics to a slow-rebound regime with an increased probability of local parasite extinction.
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Affiliation(s)
- Qi Zhan
- Committee on Genetics, Genomics and Systems Biology, The University of Chicago; Chicago, IL, 60637, USA
| | - Qixin He
- Department of Biological Sciences, Purdue University; West Lafayette, IN, 47907, USA
| | - Kathryn E Tiedje
- Department of Microbiology and Immunology, Bio21 Institute and Peter Doherty Institute, The University of Melbourne; Melbourne, Australia
| | - Karen P Day
- Department of Microbiology and Immunology, Bio21 Institute and Peter Doherty Institute, The University of Melbourne; Melbourne, Australia
| | - Mercedes Pascual
- Department of Biology, New York University; New York, NY, 10012, USA
- Department of Environmental Studies, New York University; New York, NY, 10012, USA
- Santa Fe Institute; Santa Fe, NM, 87501, USA
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5
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Andradi-Brown C, Wichers-Misterek JS, von Thien H, Höppner YD, Scholz JAM, Hansson H, Filtenborg Hocke E, Gilberger TW, Duffy MF, Lavstsen T, Baum J, Otto TD, Cunnington AJ, Bachmann A. A novel computational pipeline for var gene expression augments the discovery of changes in the Plasmodium falciparum transcriptome during transition from in vivo to short-term in vitro culture. eLife 2024; 12:RP87726. [PMID: 38270586 PMCID: PMC10945709 DOI: 10.7554/elife.87726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2024] Open
Abstract
The pathogenesis of severe Plasmodium falciparum malaria involves cytoadhesive microvascular sequestration of infected erythrocytes, mediated by P. falciparum erythrocyte membrane protein 1 (PfEMP1). PfEMP1 variants are encoded by the highly polymorphic family of var genes, the sequences of which are largely unknown in clinical samples. Previously, we published new approaches for var gene profiling and classification of predicted binding phenotypes in clinical P. falciparum isolates (Wichers et al., 2021), which represented a major technical advance. Building on this, we report here a novel method for var gene assembly and multidimensional quantification from RNA-sequencing that outperforms the earlier approach of Wichers et al., 2021, on both laboratory and clinical isolates across a combination of metrics. Importantly, the tool can interrogate the var transcriptome in context with the rest of the transcriptome and can be applied to enhance our understanding of the role of var genes in malaria pathogenesis. We applied this new method to investigate changes in var gene expression through early transition of parasite isolates to in vitro culture, using paired sets of ex vivo samples from our previous study, cultured for up to three generations. In parallel, changes in non-polymorphic core gene expression were investigated. Modest but unpredictable var gene switching and convergence towards var2csa were observed in culture, along with differential expression of 19% of the core transcriptome between paired ex vivo and generation 1 samples. Our results cast doubt on the validity of the common practice of using short-term cultured parasites to make inferences about in vivo phenotype and behaviour.
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Affiliation(s)
- Clare Andradi-Brown
- Section of Paediatric Infectious Disease, Department of Infectious Disease, Imperial College LondonLondonUnited Kingdom
- Department of Life Sciences, Imperial College London, South KensingtonLondonUnited Kingdom
- Centre for Paediatrics and Child Health, Imperial College LondonLondonUnited Kingdom
| | - Jan Stephan Wichers-Misterek
- Bernhard Nocht Institute for Tropical Medicine, Bernhard-Nocht-StrasseHamburgGermany
- Centre for Structural Systems BiologyHamburgGermany
- Biology Department, University of HamburgHamburgGermany
| | - Heidrun von Thien
- Bernhard Nocht Institute for Tropical Medicine, Bernhard-Nocht-StrasseHamburgGermany
- Centre for Structural Systems BiologyHamburgGermany
- Biology Department, University of HamburgHamburgGermany
| | - Yannick D Höppner
- Bernhard Nocht Institute for Tropical Medicine, Bernhard-Nocht-StrasseHamburgGermany
- Centre for Structural Systems BiologyHamburgGermany
- Biology Department, University of HamburgHamburgGermany
| | - Judith AM Scholz
- Bernhard Nocht Institute for Tropical Medicine, Bernhard-Nocht-StrasseHamburgGermany
| | - Helle Hansson
- Center for Medical Parasitology, Department of Immunology and Microbiology, University of CopenhagenCopenhagenDenmark
- Department of Infectious Diseases, Copenhagen University HospitalCopenhagenDenmark
| | - Emma Filtenborg Hocke
- Center for Medical Parasitology, Department of Immunology and Microbiology, University of CopenhagenCopenhagenDenmark
- Department of Infectious Diseases, Copenhagen University HospitalCopenhagenDenmark
| | - Tim Wolf Gilberger
- Bernhard Nocht Institute for Tropical Medicine, Bernhard-Nocht-StrasseHamburgGermany
- Centre for Structural Systems BiologyHamburgGermany
- Biology Department, University of HamburgHamburgGermany
| | - Michael F Duffy
- Department of Microbiology and Immunology, University of MelbourneMelbourneAustralia
| | - Thomas Lavstsen
- Center for Medical Parasitology, Department of Immunology and Microbiology, University of CopenhagenCopenhagenDenmark
- Department of Infectious Diseases, Copenhagen University HospitalCopenhagenDenmark
| | - Jake Baum
- Department of Life Sciences, Imperial College London, South KensingtonLondonUnited Kingdom
- School of Biomedical Sciences, Faculty of Medicine & Health, UNSW, KensingtonSydneyUnited Kingdom
| | - Thomas D Otto
- School of Infection & Immunity, MVLS, University of GlasgowGlasgowUnited Kingdom
| | - Aubrey J Cunnington
- Section of Paediatric Infectious Disease, Department of Infectious Disease, Imperial College LondonLondonUnited Kingdom
- Centre for Paediatrics and Child Health, Imperial College LondonLondonUnited Kingdom
| | - Anna Bachmann
- Bernhard Nocht Institute for Tropical Medicine, Bernhard-Nocht-StrasseHamburgGermany
- Centre for Structural Systems BiologyHamburgGermany
- Biology Department, University of HamburgHamburgGermany
- German Center for Infection Research (DZIF), partner site Hamburg-Borstel-Lübeck-RiemsHamburgGermany
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6
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Palmateer NC, Munro JB, Nagaraj S, Crabtree J, Pelle R, Tallon L, Nene V, Bishop R, Silva JC. The Hypervariable Tpr Multigene Family of Theileria Parasites, Defined by a Conserved, Membrane-Associated, C-Terminal Domain, Includes Several Copies with Defined Orthology Between Species. J Mol Evol 2023; 91:897-911. [PMID: 38017120 PMCID: PMC10730637 DOI: 10.1007/s00239-023-10142-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Accepted: 11/07/2023] [Indexed: 11/30/2023]
Abstract
Multigene families often play an important role in host-parasite interactions. One of the largest multigene families in Theileria parva, the causative agent of East Coast fever, is the T. parva repeat (Tpr) gene family. The function of the putative Tpr proteins remains unknown. The initial publication of the T. parva reference genome identified 39 Tpr family open reading frames (ORFs) sharing a conserved C-terminal domain. Twenty-eight of these are clustered in a central region of chromosome 3, termed the "Tpr locus", while others are dispersed throughout all four nuclear chromosomes. The Tpr locus contains three of the four assembly gaps remaining in the genome, suggesting the presence of additional, as yet uncharacterized, Tpr gene copies. Here, we describe the use of long-read sequencing to attempt to close the gaps in the reference assembly of T. parva (located among multigene families clusters), characterize the full complement of Tpr family ORFs in the T. parva reference genome, and evaluate their evolutionary relationship with Tpr homologs in other Theileria species. We identify three new Tpr family genes in the T. parva reference genome and show that sequence similarity among paralogs in the Tpr locus is significantly higher than between genes outside the Tpr locus. We also identify sequences homologous to the conserved C-terminal domain in five additional Theileria species. Using these sequences, we show that the evolution of this gene family involves conservation of a few orthologs across species, combined with gene gains/losses, and species-specific expansions.
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Affiliation(s)
- Nicholas C Palmateer
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - James B Munro
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Sushma Nagaraj
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Jonathan Crabtree
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Roger Pelle
- International Livestock Research Institute, Nairobi, Kenya
| | - Luke Tallon
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Vish Nene
- International Livestock Research Institute, Nairobi, Kenya
| | - Richard Bishop
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA, USA
| | - Joana C Silva
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, USA.
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, USA.
- Global Health and Tropical Medicine, GHTM, Instituto de Higiene E Medicina Tropical, IHMT, Universidade NOVA de Lisboa, UNL, Lisbon, Portugal.
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7
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Othman B, Zeef L, Szestak T, Rchiad Z, Storm J, Askonas C, Satyam R, Madkhali A, Haley M, Wagstaff S, Couper K, Pain A, Craig A. Different PfEMP1-expressing Plasmodium falciparum variants induce divergent endothelial transcriptional responses during co-culture. PLoS One 2023; 18:e0295053. [PMID: 38033133 PMCID: PMC10688957 DOI: 10.1371/journal.pone.0295053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Accepted: 11/14/2023] [Indexed: 12/02/2023] Open
Abstract
The human malaria parasite Plasmodium falciparum is responsible for the majority of mortality and morbidity caused by malaria infection and differs from other human malaria species in the degree of accumulation of parasite-infected red blood cells in the microvasculature, known as cytoadherence or sequestration. In P. falciparum, cytoadherence is mediated by a protein called PfEMP1 which, due to its exposure to the host immune system, undergoes antigenic variation resulting in the expression of different PfEMP1 variants on the infected erythrocyte membrane. These PfEMP1s contain various combinations of adhesive domains, which allow for the differential engagement of a repertoire of endothelial receptors on the host microvasculature, with specific receptor usage associated with severe disease. We used a co-culture model of cytoadherence incubating human brain microvascular endothelial cells with erythrocytes infected with two parasite lines expressing different PfEMP1s that demonstrate different binding profiles to vascular endothelium. We determined the transcriptional profile of human brain microvascular endothelial cells (HBMEC) following different incubation periods with infected erythrocytes, identifying different transcriptional profiles of pathways previously found to be involved in the pathology of severe malaria, such as inflammation, apoptosis and barrier integrity, induced by the two PfEMP1 variants.
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Affiliation(s)
- Basim Othman
- Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, United Kingdom
| | - Leo Zeef
- Faculty of Biology, Medicine and Health, The Lydia Becker Institute of Immunology and Inflammation, University of Manchester, Manchester, United Kingdom
| | - Tadge Szestak
- Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, United Kingdom
| | - Zineb Rchiad
- Pathogen Genomics Laboratory, Bioscience Program, Biological and Environmental Sciences and Engineering (BESE) Division, King Abdullah University of Science and Technology, Thuwal, KSA
| | - Janet Storm
- Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, United Kingdom
| | - Caroline Askonas
- Pathogen Genomics Laboratory, Bioscience Program, Biological and Environmental Sciences and Engineering (BESE) Division, King Abdullah University of Science and Technology, Thuwal, KSA
| | - Rohit Satyam
- Pathogen Genomics Laboratory, Bioscience Program, Biological and Environmental Sciences and Engineering (BESE) Division, King Abdullah University of Science and Technology, Thuwal, KSA
| | - Aymen Madkhali
- Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, United Kingdom
| | - Michael Haley
- Faculty of Biology, Medicine and Health, The Lydia Becker Institute of Immunology and Inflammation, University of Manchester, Manchester, United Kingdom
| | - Simon Wagstaff
- Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, United Kingdom
| | - Kevin Couper
- Faculty of Biology, Medicine and Health, The Lydia Becker Institute of Immunology and Inflammation, University of Manchester, Manchester, United Kingdom
| | - Arnab Pain
- Pathogen Genomics Laboratory, Bioscience Program, Biological and Environmental Sciences and Engineering (BESE) Division, King Abdullah University of Science and Technology, Thuwal, KSA
| | - Alister Craig
- Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, United Kingdom
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8
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Tan MH, Tiedje KE, Feng Q, Zhan Q, Pascual M, Shim H, Chan YB, Day KP. A paradoxical population structure of var DBLα types in Africa. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.05.565723. [PMID: 37986738 PMCID: PMC10659346 DOI: 10.1101/2023.11.05.565723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
The var multigene family encodes the P. falciparum erythrocyte membrane protein 1 (PfEMP1), which is important in host-parasite interaction as a virulence factor and major surface antigen of the blood stages of the parasite, responsible for maintaining chronic infection. Whilst important in the biology of P. falciparum, these genes (50 to 60 genes per parasite genome) are routinely excluded from whole genome analyses due to their hyper-diversity, achieved primarily through recombination. The PfEMP1 head structure almost always consists of a DBLα-CIDR tandem. Categorised into different groups (upsA, upsB, upsC), different head structures have been associated with different ligand-binding affinities and disease severities. We study how conserved individual DBLα types are at the country, regional, and local scales in Sub-Saharan Africa. Using publicly-available sequence datasets and a novel ups classification algorithm, cUps, we performed an in silico exploration of DBLα conservation through time and space in Africa. In all three ups groups, the population structure of DBLα types in Africa consists of variants occurring at rare, low, moderate, and high frequencies. Non-rare variants were found to be temporally stable in a local area in endemic Ghana. When inspected across different geographical scales, we report different levels of conservation; while some DBLα types were consistently found in high frequencies in multiple African countries, others were conserved only locally, signifying local preservation of specific types. Underlying this population pattern is the composition of DBLα types within each isolate DBLα repertoire, revealed to also consist of a mix of types found at rare, low, moderate, and high frequencies in the population. We further discuss the adaptive forces and balancing selection, including host genetic factors, potentially shaping the evolution and diversity of DBLα types in Africa.
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Affiliation(s)
- Mun Hua Tan
- Department of Microbiology and Immunology, The University of Melbourne, Bio21 Institute and Peter Doherty Institute, Melbourne, AU
| | - Kathryn E Tiedje
- Department of Microbiology and Immunology, The University of Melbourne, Bio21 Institute and Peter Doherty Institute, Melbourne, AU
| | - Qian Feng
- School of Mathematics and Statistics / Melbourne Integrative Genomics, The University of Melbourne, Melbourne, Australia
| | - Qi Zhan
- Department of Ecology and Evolution, University of Chicago; Chicago, Illinois, USA
| | - Mercedes Pascual
- Department of Ecology and Evolution, University of Chicago; Chicago, Illinois, USA
| | - Heejung Shim
- School of Mathematics and Statistics / Melbourne Integrative Genomics, The University of Melbourne, Melbourne, Australia
| | - Yao-Ban Chan
- School of Mathematics and Statistics / Melbourne Integrative Genomics, The University of Melbourne, Melbourne, Australia
| | - Karen P Day
- Department of Microbiology and Immunology, The University of Melbourne, Bio21 Institute and Peter Doherty Institute, Melbourne, AU
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9
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Tiedje KE, Zhan Q, Ruybal-Pésantez S, Tonkin-Hill G, He Q, Tan MH, Argyropoulos DC, Deed SL, Ghansah A, Bangre O, Oduro AR, Koram KA, Pascual M, Day KP. Measuring changes in Plasmodium falciparum census population size in response to sequential malaria control interventions. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2023:2023.05.18.23290210. [PMID: 37292908 PMCID: PMC10246142 DOI: 10.1101/2023.05.18.23290210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Here we introduce a new endpoint "census population size" to evaluate the epidemiology and control of Plasmodium falciparum infections, where the parasite, rather than the infected human host, is the unit of measurement. To calculate census population size, we rely on a definition of parasite variation known as multiplicity of infection (M O I v a r ), based on the hyper-diversity of the v a r multigene family. We present a Bayesian approach to estimate M O I v a r from sequencing and counting the number of unique DBLα tags (or DBLα types) of v a r genes, and derive from it census population size by summation of M O I v a r in the human population. We track changes in this parasite population size and structure through sequential malaria interventions by indoor residual spraying (IRS) and seasonal malaria chemoprevention (SMC) from 2012 to 2017 in an area of high-seasonal malaria transmission in northern Ghana. Following IRS, which reduced transmission intensity by > 90% and decreased parasite prevalence by ~40-50%, significant reductions in v a r diversity, M O I v a r , and population size were observed in ~2,000 humans across all ages. These changes, consistent with the loss of diverse parasite genomes, were short lived and 32-months after IRS was discontinued and SMC was introduced, v a r diversity and population size rebounded in all age groups except for the younger children (1-5 years) targeted by SMC. Despite major perturbations from IRS and SMC interventions, the parasite population remained very large and retained the v a r population genetic characteristics of a high-transmission system (high v a r diversity; low v a r repertoire similarity) demonstrating the resilience of P. falciparum to short-term interventions in high-burden countries of sub-Saharan Africa.
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Affiliation(s)
- Kathryn E. Tiedje
- Department of Microbiology and Immunology, Bio21 Institute and Peter Doherty Institute, The University of Melbourne; Melbourne, Australia
- School of BioSciences, Bio21 Institute, The University of Melbourne; Melbourne, Australia
| | - Qi Zhan
- Committee on Genetics, Genomics and Systems Biology, The University of Chicago; Chicago, Illinois, USA
- Department of Ecology and Evolution, The University of Chicago; Chicago, Illinois, USA
| | - Shazia Ruybal-Pésantez
- School of BioSciences, Bio21 Institute, The University of Melbourne; Melbourne, Australia
| | - Gerry Tonkin-Hill
- School of BioSciences, Bio21 Institute, The University of Melbourne; Melbourne, Australia
- Bioinformatics Division, Walter and Eliza Hall Institute; Melbourne, Australia
| | - Qixin He
- Department of Ecology and Evolution, The University of Chicago; Chicago, Illinois, USA
| | - Mun Hua Tan
- Department of Microbiology and Immunology, Bio21 Institute and Peter Doherty Institute, The University of Melbourne; Melbourne, Australia
| | - Dionne C. Argyropoulos
- Department of Microbiology and Immunology, Bio21 Institute and Peter Doherty Institute, The University of Melbourne; Melbourne, Australia
| | - Samantha L. Deed
- Department of Microbiology and Immunology, Bio21 Institute and Peter Doherty Institute, The University of Melbourne; Melbourne, Australia
- School of BioSciences, Bio21 Institute, The University of Melbourne; Melbourne, Australia
| | - Anita Ghansah
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, University of Ghana; Legon, Ghana
| | - Oscar Bangre
- Navrongo Health Research Centre, Ghana Health Service; Navrongo, Ghana
| | - Abraham R. Oduro
- Navrongo Health Research Centre, Ghana Health Service; Navrongo, Ghana
| | - Kwadwo A. Koram
- Epidemiology Department, Noguchi Memorial Institute for Medical Research, University of Ghana; Legon, Ghana
| | - Mercedes Pascual
- Department of Ecology and Evolution, The University of Chicago; Chicago, Illinois, USA
- Santa Fe Institute, Santa Fe, New Mexico, USA
| | - Karen P. Day
- Department of Microbiology and Immunology, Bio21 Institute and Peter Doherty Institute, The University of Melbourne; Melbourne, Australia
- School of BioSciences, Bio21 Institute, The University of Melbourne; Melbourne, Australia
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10
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Wichers-Misterek JS, Krumkamp R, Held J, von Thien H, Wittmann I, Höppner YD, Ruge JM, Moser K, Dara A, Strauss J, Esen M, Fendel R, Sulyok Z, Jeninga MD, Kremsner PG, Sim BKL, Hoffman SL, Duffy MF, Otto TD, Gilberger TW, Silva JC, Mordmüller B, Petter M, Bachmann A. The exception that proves the rule: Virulence gene expression at the onset of Plasmodium falciparum blood stage infections. PLoS Pathog 2023; 19:e1011468. [PMID: 37384799 DOI: 10.1371/journal.ppat.1011468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Accepted: 06/07/2023] [Indexed: 07/01/2023] Open
Abstract
Controlled human malaria infections (CHMI) are a valuable tool to study parasite gene expression in vivo under defined conditions. In previous studies, virulence gene expression was analyzed in samples from volunteers infected with the Plasmodium falciparum (Pf) NF54 isolate, which is of African origin. Here, we provide an in-depth investigation of parasite virulence gene expression in malaria-naïve European volunteers undergoing CHMI with the genetically distinct Pf 7G8 clone, originating in Brazil. Differential expression of var genes, encoding major virulence factors of Pf, PfEMP1s, was assessed in ex vivo parasite samples as well as in parasites from the in vitro cell bank culture that was used to generate the sporozoites (SPZ) for CHMI (Sanaria PfSPZ Challenge (7G8)). We report broad activation of mainly B-type subtelomeric located var genes at the onset of a 7G8 blood stage infection in naïve volunteers, mirroring the NF54 expression study and suggesting that the expression of virulence-associated genes is generally reset during transmission from the mosquito to the human host. However, in 7G8 parasites, we additionally detected a continuously expressed single C-type variant, Pf7G8_040025600, that was most highly expressed in both pre-mosquito cell bank and volunteer samples, suggesting that 7G8, unlike NF54, maintains expression of some previously expressed var variants during transmission. This suggests that in a new host, the parasite may preferentially express the variants that previously allowed successful infection and transmission. Trial registration: ClinicalTrials.gov - NCT02704533; 2018-004523-36.
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Affiliation(s)
- Jan Stephan Wichers-Misterek
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
- Centre for Structural Systems Biology, Hamburg, Germany, Hamburg, Germany
- Biology Department, University of Hamburg, Hamburg, Germany
| | - Ralf Krumkamp
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
- German Center for Infection Research (DZIF), partner site Hamburg-Borstel-Lübeck-Riems, Hamburg/Borstel/Lübeck/Riems, Germany
| | - Jana Held
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
- German Center for Infection Research (DZIF), partner site Tübingen, Tübingen, Germany
| | - Heidrun von Thien
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
- Centre for Structural Systems Biology, Hamburg, Germany, Hamburg, Germany
- Biology Department, University of Hamburg, Hamburg, Germany
| | - Irene Wittmann
- Institute of Microbiology, University Hospital Erlangen, Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany
| | - Yannick Daniel Höppner
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
- Centre for Structural Systems Biology, Hamburg, Germany, Hamburg, Germany
- Biology Department, University of Hamburg, Hamburg, Germany
- German Center for Infection Research (DZIF), partner site Hamburg-Borstel-Lübeck-Riems, Hamburg/Borstel/Lübeck/Riems, Germany
| | - Julia M Ruge
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
- Centre for Structural Systems Biology, Hamburg, Germany, Hamburg, Germany
- Biology Department, University of Hamburg, Hamburg, Germany
- German Center for Infection Research (DZIF), partner site Hamburg-Borstel-Lübeck-Riems, Hamburg/Borstel/Lübeck/Riems, Germany
| | - Kara Moser
- Institute for Genome Sciences, University of Maryland, School of Medicine, Baltimore, Maryland, United States of America
| | - Antoine Dara
- Institute for Genome Sciences, University of Maryland, School of Medicine, Baltimore, Maryland, United States of America
| | - Jan Strauss
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
- Centre for Structural Systems Biology, Hamburg, Germany, Hamburg, Germany
- Biology Department, University of Hamburg, Hamburg, Germany
| | - Meral Esen
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
- German Center for Infection Research (DZIF), partner site Tübingen, Tübingen, Germany
- Cluster of Excellence: EXC 2124: Controlling Microbes to Fight Infection, Tübingen, Germany
| | - Rolf Fendel
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
- German Center for Infection Research (DZIF), partner site Tübingen, Tübingen, Germany
| | - Zita Sulyok
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
- German Center for Infection Research (DZIF), partner site Tübingen, Tübingen, Germany
| | - Myriam D Jeninga
- Institute of Microbiology, University Hospital Erlangen, Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany
| | - Peter G Kremsner
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
- German Center for Infection Research (DZIF), partner site Tübingen, Tübingen, Germany
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
| | - B Kim Lee Sim
- Sanaria Inc., Rockville, Maryland, United States of America
| | | | - Michael F Duffy
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, Victoria, Australia
| | - Thomas D Otto
- School of Infection & Immunity, University of Glasgow, Glasgow, United Kingdom
| | - Tim-Wolf Gilberger
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
- Centre for Structural Systems Biology, Hamburg, Germany, Hamburg, Germany
- Biology Department, University of Hamburg, Hamburg, Germany
| | - Joana C Silva
- Institute for Genome Sciences, University of Maryland, School of Medicine, Baltimore, Maryland, United States of America
- Department of Microbiology and Immunology, University of Maryland, School of Medicine, Baltimore, Maryland, United States of America
- Global Health and Tropical Medicine, GHTM, Instituto de Higiene e Medicina Tropical, IHMT, Universidade NOVA de Lisboa, UNL, Lisboa, Portugal
| | - Benjamin Mordmüller
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
- German Center for Infection Research (DZIF), partner site Tübingen, Tübingen, Germany
| | - Michaela Petter
- Institute of Microbiology, University Hospital Erlangen, Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, Victoria, Australia
| | - Anna Bachmann
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
- Centre for Structural Systems Biology, Hamburg, Germany, Hamburg, Germany
- Biology Department, University of Hamburg, Hamburg, Germany
- German Center for Infection Research (DZIF), partner site Hamburg-Borstel-Lübeck-Riems, Hamburg/Borstel/Lübeck/Riems, Germany
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11
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Tan MH, Shim H, Chan YB, Day KP. Unravelling var complexity: Relationship between DBLα types and var genes in Plasmodium falciparum. FRONTIERS IN PARASITOLOGY 2023; 1. [PMID: 36998722 PMCID: PMC10060044 DOI: 10.3389/fpara.2022.1006341] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The enormous diversity and complexity of var genes that diversify rapidly by recombination has led to the exclusion of assembly of these genes from major genome initiatives (e.g., Pf6). A scalable solution in epidemiological surveillance of var genes is to use a small ‘tag’ region encoding the immunogenic DBLα domain as a marker to estimate var diversity. As var genes diversify by recombination, it is not clear the extent to which the same tag can appear in multiple var genes. This relationship between marker and gene has not been investigated in natural populations. Analyses of in vitro recombination within and between var genes have suggested that this relationship would not be exclusive. Using a dataset of publicly-available assembled var sequences, we test this hypothesis by studying DBLα-var relationships for four study sites in four countries: Pursat (Cambodia) and Mae Sot (Thailand), representing low malaria transmission, and Navrongo (Ghana) and Chikwawa (Malawi), representing high malaria transmission. In all study sites, DBLα-var relationships were shown to be predominantly 1-to-1, followed by a second largest proportion of 1-to-2 DBLα-var relationships. This finding indicates that DBLα tags can be used to estimate not just DBLα diversity but var gene diversity when applied in a local endemic area. Epidemiological applications of this result are discussed.
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Affiliation(s)
- Mun Hua Tan
- Department of Microbiology and Immunology, The University of Melbourne, Bio21 Institute, Melbourne, VIC, Australia
| | - Heejung Shim
- School of Mathematics and Statistics/Melbourne Integrative Genomics, The University of Melbourne, Melbourne, VIC, Australia
| | - Yao-ban Chan
- School of Mathematics and Statistics/Melbourne Integrative Genomics, The University of Melbourne, Melbourne, VIC, Australia
| | - Karen P. Day
- Department of Microbiology and Immunology, The University of Melbourne, Bio21 Institute, Melbourne, VIC, Australia
- CORRESPONDENCE Karen P. Day,
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12
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Zanghi G, Patel H, Camargo N, Smith JL, Bae Y, Flannery EL, Chuenchob V, Fishbaugher ME, Mikolajczak SA, Roobsoong W, Sattabongkot J, Hayes K, Vaughan AM, Kappe SHI. Global gene expression of human malaria parasite liver stages throughout intrahepatocytic development. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.05.522945. [PMID: 36711670 PMCID: PMC9881933 DOI: 10.1101/2023.01.05.522945] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Plasmodium falciparum (Pf) is causing the greatest malaria burden, yet the liver stages (LS) of this most important parasite species have remained poorly studied. Here, we used a human liver-chimeric mouse model in combination with a novel fluorescent PfNF54 parasite line (PfNF54cspGFP) to isolate PfLS-infected hepatocytes and generate transcriptomes that cover the major LS developmental phases in human hepatocytes. RNA-seq analysis of early Pf LS trophozoites two days after infection, revealed a central role of translational regulation in the transformation of the extracellular invasive sporozoite into intracellular LS. The developmental time course gene expression analysis indicated that fatty acid biosynthesis, isoprenoid biosynthesis and iron metabolism are sustaining LS development along with amino acid metabolism and biosynthesis. Countering oxidative stress appears to play an important role during intrahepatic LS development. Furthermore, we observed expression of the variant PfEMP1 antigen-encoding var genes, and we confirmed expression of PfEMP1 protein during LS development. Transcriptome comparison of the late Pf liver stage schizonts with P. vivax (Pv) late liver stages revealed highly conserved gene expression profiles among orthologous genes. A notable difference however was the expression of genes regulating sexual stage commitment. While Pv schizonts expressed markers of sexual commitment, the Pf LS parasites were not sexually committed and showed expression of gametocytogenesis repression factors. Our results provide the first comprehensive gene expression profile of the human malaria parasite Pf LS isolated during in vivo intrahepatocytic development. This data will inform biological studies and the search for effective intervention strategies that can prevent infection.
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Affiliation(s)
- Gigliola Zanghi
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, Washington, United States of America
| | - Hardik Patel
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, Washington, United States of America
| | - Nelly Camargo
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, Washington, United States of America
| | - Jenny L. Smith
- Research Scientific Computing, Seattle Children’s Research Institute, Seattle, Washington, United States of America
| | - Yeji Bae
- Research Scientific Computing, Seattle Children’s Research Institute, Seattle, Washington, United States of America
| | - Erika L. Flannery
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, Washington, United States of America
- Novartis Institute for Tropical Diseases, Emeryville, CA, United State
| | - Vorada Chuenchob
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, Washington, United States of America
- Novartis Institute for Tropical Diseases, Emeryville, CA, United State
| | - Matthew E. Fishbaugher
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, Washington, United States of America
- Novartis Institute for Tropical Diseases, Emeryville, CA, United State
| | - Sebastian A Mikolajczak
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, Washington, United States of America
- Novartis Institute for Tropical Diseases, Emeryville, CA, United State
| | - Wanlapa Roobsoong
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand
| | - Jetsumon Sattabongkot
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand
| | - Kiera Hayes
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, Washington, United States of America
| | - Ashley M. Vaughan
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, Washington, United States of America
- Department of Pediatrics, University of Washington
- Department of Global Health, University of Washington, Seattle, Washington, United States of America
| | - Stefan H. I. Kappe
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, Washington, United States of America
- Department of Pediatrics, University of Washington
- Department of Global Health, University of Washington, Seattle, Washington, United States of America
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13
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Labbé F, He Q, Zhan Q, Tiedje KE, Argyropoulos DC, Tan MH, Ghansah A, Day KP, Pascual M. Neutral vs. non-neutral genetic footprints of Plasmodium falciparum multiclonal infections. PLoS Comput Biol 2023; 19:e1010816. [PMID: 36595546 PMCID: PMC9838855 DOI: 10.1371/journal.pcbi.1010816] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Revised: 01/13/2023] [Accepted: 12/14/2022] [Indexed: 01/04/2023] Open
Abstract
At a time when effective tools for monitoring malaria control and eradication efforts are crucial, the increasing availability of molecular data motivates their application to epidemiology. The multiplicity of infection (MOI), defined as the number of genetically distinct parasite strains co-infecting a host, is one key epidemiological parameter for evaluating malaria interventions. Estimating MOI remains a challenge for high-transmission settings where individuals typically carry multiple co-occurring infections. Several quantitative approaches have been developed to estimate MOI, including two cost-effective ones relying on molecular data: i) THE REAL McCOIL method is based on putatively neutral single nucleotide polymorphism loci, and ii) the varcoding method is a fingerprinting approach that relies on the diversity and limited repertoire overlap of the var multigene family encoding the major Plasmodium falciparum blood-stage antigen PfEMP1 and is therefore under selection. In this study, we assess the robustness of the MOI estimates generated with these two approaches by simulating P. falciparum malaria dynamics under three transmission conditions using an extension of a previously developed stochastic agent-based model. We demonstrate that these approaches are complementary and best considered across distinct transmission intensities. While varcoding can underestimate MOI, it allows robust estimation, especially under high transmission where repertoire overlap is extremely limited from frequency-dependent selection. In contrast, THE REAL McCOIL often considerably overestimates MOI, but still provides reasonable estimates for low and moderate transmission. Regardless of transmission intensity, results for THE REAL McCOIL indicate that an inaccurate tail at high MOI values is generated, and that at high transmission, an apparently reasonable estimated MOI distribution can arise from some degree of compensation between overestimation and underestimation. As many countries pursue malaria elimination targets, defining the most suitable approach to estimate MOI based on sample size and local transmission intensity is highly recommended for monitoring the impact of intervention programs.
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Affiliation(s)
- Frédéric Labbé
- Department of Ecology and Evolution, The University of Chicago, Chicago, Illinois, United States of America
| | - Qixin He
- Department of Biological Sciences, Purdue University, West Lafayette, Indianapolis, United States of America
| | - Qi Zhan
- Department of Ecology and Evolution, The University of Chicago, Chicago, Illinois, United States of America
| | - Kathryn E. Tiedje
- School of BioSciences, Bio21 Institute, The University of Melbourne, Melbourne, Australia
- Department of Microbiology and Immunology, Bio21 Institute and Peter Doherty Institute, The University of Melbourne, Melbourne, Australia
| | - Dionne C. Argyropoulos
- School of BioSciences, Bio21 Institute, The University of Melbourne, Melbourne, Australia
- Department of Microbiology and Immunology, Bio21 Institute and Peter Doherty Institute, The University of Melbourne, Melbourne, Australia
| | - Mun Hua Tan
- School of BioSciences, Bio21 Institute, The University of Melbourne, Melbourne, Australia
- Department of Microbiology and Immunology, Bio21 Institute and Peter Doherty Institute, The University of Melbourne, Melbourne, Australia
| | - Anita Ghansah
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, College of Health Science, University of Ghana, Legon, Ghana
| | - Karen P. Day
- School of BioSciences, Bio21 Institute, The University of Melbourne, Melbourne, Australia
- Department of Microbiology and Immunology, Bio21 Institute and Peter Doherty Institute, The University of Melbourne, Melbourne, Australia
| | - Mercedes Pascual
- Department of Ecology and Evolution, The University of Chicago, Chicago, Illinois, United States of America
- Santa Fe Institute, Santa Fe, New Mexico, United States of America
- * E-mail:
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14
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Akide Ndunge OB, Kilian N, Salman MM. Cerebral Malaria and Neuronal Implications of Plasmodium Falciparum Infection: From Mechanisms to Advanced Models. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2202944. [PMID: 36300890 PMCID: PMC9798991 DOI: 10.1002/advs.202202944] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 09/22/2022] [Indexed: 06/01/2023]
Abstract
Reorganization of host red blood cells by the malaria parasite Plasmodium falciparum enables their sequestration via attachment to the microvasculature. This artificially increases the dwelling time of the infected red blood cells within inner organs such as the brain, which can lead to cerebral malaria. Cerebral malaria is the deadliest complication patients infected with P. falciparum can experience and still remains a major public health concern despite effective antimalarial therapies. Here, the current understanding of the effect of P. falciparum cytoadherence and their secreted proteins on structural features of the human blood-brain barrier and their involvement in the pathogenesis of cerebral malaria are highlighted. Advanced 2D and 3D in vitro models are further assessed to study this devastating interaction between parasite and host. A better understanding of the molecular mechanisms leading to neuronal and cognitive deficits in cerebral malaria will be pivotal in devising new strategies to treat and prevent blood-brain barrier dysfunction and subsequent neurological damage in patients with cerebral malaria.
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Affiliation(s)
- Oscar Bate Akide Ndunge
- Department of Internal MedicineSection of Infectious DiseasesYale University School of Medicine300 Cedar StreetNew HavenCT06510USA
| | - Nicole Kilian
- Centre for Infectious Diseases, ParasitologyHeidelberg University HospitalIm Neuenheimer Feld 32469120HeidelbergGermany
| | - Mootaz M. Salman
- Department of PhysiologyAnatomy and GeneticsUniversity of OxfordOxfordOX1 3QUUK
- Kavli Institute for NanoScience DiscoveryUniversity of OxfordOxfordUK
- Oxford Parkinson's Disease CentreUniversity of OxfordOxfordUK
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15
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CD36-A Host Receptor Necessary for Malaria Parasites to Establish and Maintain Infection. Microorganisms 2022; 10:microorganisms10122356. [PMID: 36557610 PMCID: PMC9785914 DOI: 10.3390/microorganisms10122356] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 11/21/2022] [Accepted: 11/27/2022] [Indexed: 11/30/2022] Open
Abstract
Plasmodium falciparum-infected erythrocytes (PfIEs) present P. falciparum erythrocyte membrane protein 1 proteins (PfEMP1s) on the cell surface, via which they cytoadhere to various endothelial cell receptors (ECRs) on the walls of human blood vessels. This prevents the parasite from passing through the spleen, which would lead to its elimination. Each P. falciparum isolate has about 60 different PfEMP1s acting as ligands, and at least 24 ECRs have been identified as interaction partners. Interestingly, in every parasite genome sequenced to date, at least 75% of the encoded PfEMP1s have a binding domain for the scavenger receptor CD36 widely distributed on host endothelial cells and many other cell types. Here, we discuss why the interaction between PfIEs and CD36 is optimal to maintain a finely regulated equilibrium that allows the parasite to multiply and spread while causing minimal harm to the host in most infections.
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16
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Suurbaar J, Moussiliou A, Tahar R, Olsen RW, Adams Y, Dalgaard N, Baafour EK, Adukpo S, Hviid L, Kusi KA, Alao J, Ofori MF, Ndam NT, Jensen AR. ICAM-1-binding Plasmodium falciparum erythrocyte membrane protein 1 variants elicits opsonic-phagocytosis IgG responses in Beninese children. Sci Rep 2022; 12:12994. [PMID: 35906450 PMCID: PMC9338288 DOI: 10.1038/s41598-022-16305-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Accepted: 07/07/2022] [Indexed: 11/09/2022] Open
Abstract
Members of the highly polymorphic Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) family expressed on the surface of infected erythrocytes (IEs) are important virulence factors, which mediate vascular adhesion of IEs via endothelial host receptors and are targets of naturally acquired immunity. The PfEMP1 family can be divided into clinically relevant subgroups, of which some bind intercellular adhesion molecule 1 (ICAM-1). While the acquisition of IgG specific for ICAM-1-binding DBLβ domains is known to differ between PfEMP1 groups, its ability to induce antibody-dependent cellular phagocytosis (ADCP) is unclear. We therefore measured plasma levels of DBLβ-specific IgG, the ability of such IgG to inhibit PfEMP1-binding to ICAM-1, and its ability to opsonize IEs for ADCP, using plasma from Beninese children with severe (SM) or uncomplicated malaria (UM). IgG specific for DBLβ from group A and B ICAM-1-binding PfEMP1 were dominated by IgG1 and IgG3, and were similar in SM and UM. However, levels of plasma IgG inhibiting ICAM-1-binding of group A DBLβ of PFD1235w was significantly higher in children with UM than SM, and acute UM plasma induced a higher ADCP response than acute SM plasma.
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Affiliation(s)
- Jennifer Suurbaar
- Department of Immunology, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana.,Department of Biochemistry, Cell and Molecular Biology, West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, Legon, Ghana.,Department of Biochemistry and Molecular Medicine, School of Medicine and Health Sciences, University for Development Studies, Tamale, Ghana.,Centre for Medical Parasitology at Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Université de Paris Cité, MERIT, IRD, 75006, Paris, France
| | | | - Rachida Tahar
- Université de Paris Cité, MERIT, IRD, 75006, Paris, France
| | - Rebecca W Olsen
- Centre for Medical Parasitology at Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Yvonne Adams
- Centre for Medical Parasitology at Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Nanna Dalgaard
- Centre for Medical Parasitology at Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Eric K Baafour
- Department of Immunology, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
| | - Selorme Adukpo
- Department of Pharmaceutics and Microbiology, School of Pharmacy, University of Ghana, Legon, Ghana
| | - Lars Hviid
- Centre for Medical Parasitology at Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), Copenhagen, Denmark
| | - Kwadwo A Kusi
- Department of Immunology, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana.,Department of Biochemistry, Cell and Molecular Biology, West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, Legon, Ghana
| | - Jules Alao
- Paediatric Department, Mother and Child University and Hospital Center (CHUMEL), Cotonou, Benin
| | - Michael F Ofori
- Department of Immunology, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana.,Department of Biochemistry, Cell and Molecular Biology, West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, Legon, Ghana
| | - Nicaise T Ndam
- Université de Paris Cité, MERIT, IRD, 75006, Paris, France
| | - Anja R Jensen
- Centre for Medical Parasitology at Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
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17
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Chew M, Ye W, Omelianczyk RI, Pasaje CF, Hoo R, Chen Q, Niles JC, Chen J, Preiser P. Selective expression of variant surface antigens enables Plasmodium falciparum to evade immune clearance in vivo. Nat Commun 2022; 13:4067. [PMID: 35831417 PMCID: PMC9279368 DOI: 10.1038/s41467-022-31741-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Accepted: 06/30/2022] [Indexed: 11/09/2022] Open
Abstract
Plasmodium falciparum has developed extensive mechanisms to evade host immune clearance. Currently, most of our understanding is based on in vitro studies of individual parasite variant surface antigens and how this relates to the processes in vivo is not well-understood. Here, we have used a humanized mouse model to identify parasite factors important for in vivo growth. We show that upregulation of the specific PfEMP1, VAR2CSA, provides the parasite with protection from macrophage phagocytosis and clearance in the humanized mice. Furthermore, parasites adapted to thrive in the humanized mice show reduced NK cell-mediated killing through interaction with the immune inhibitory receptor, LILRB1. Taken together, these findings reveal new insights into the molecular and cellular mechanisms that the parasite utilizes to coordinate immune escape in vivo. Identification and targeting of these specific parasite variant surface antigens crucial for immune evasion provides a unique approach for therapy.
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Affiliation(s)
- Marvin Chew
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore.,Singapore-MIT Alliance for Research and Technology, Antimicrobial Resistance Interdisciplinary Research Group, Singapore, Singapore
| | - Weijian Ye
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore.,Singapore-MIT Alliance for Research and Technology, Antimicrobial Resistance Interdisciplinary Research Group, Singapore, Singapore
| | | | - Charisse Flerida Pasaje
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Regina Hoo
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore.,Wellcome Sanger Institute, Hinxton, Cambridgeshire, CB101SA, UK
| | - Qingfeng Chen
- Humanized Mouse Unit, Institute of Molecular and Cell Biology, Agency of Science, Technology and Research, Singapore, Singapore
| | - Jacquin C Niles
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Jianzhu Chen
- Singapore-MIT Alliance for Research and Technology, Antimicrobial Resistance Interdisciplinary Research Group, Singapore, Singapore. .,Koch Institute for Integrative Cancer Research and Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA.
| | - Peter Preiser
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore. .,Singapore-MIT Alliance for Research and Technology, Antimicrobial Resistance Interdisciplinary Research Group, Singapore, Singapore.
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18
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Rehn T, Lubiana P, Nguyen THT, Pansegrau E, Schmitt M, Roth LK, Brehmer J, Roeder T, Cadar D, Metwally NG, Bruchhaus I. Ectopic Expression of Plasmodium vivax vir Genes in P. falciparum Affects Cytoadhesion via Increased Expression of Specific var Genes. Microorganisms 2022; 10:microorganisms10061183. [PMID: 35744701 PMCID: PMC9230084 DOI: 10.3390/microorganisms10061183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 06/01/2022] [Accepted: 06/07/2022] [Indexed: 11/16/2022] Open
Abstract
Plasmodium falciparum-infected erythrocytes (PfIEs) adhere to endothelial cell receptors (ECRs) of blood vessels mainly via PfEMP1 proteins to escape elimination via the spleen. Evidence suggests that P. vivax-infected reticulocytes (PvIRs) also bind to ECRs, presumably enabled by VIR proteins, as shown by inhibition experiments and studies with transgenic P. falciparum expressing vir genes. To test this hypothesis, our study investigated the involvement of VIR proteins in cytoadhesion using vir gene-expressing P. falciparum transfectants. Those VIR proteins with a putative transmembrane domain were present in Maurer's clefts, and some were also present in the erythrocyte membrane. The VIR protein without a transmembrane domain (PVX_050690) was not exported. Five of the transgenic P. falciparum cell lines, including the one expressing PVX_050690, showed binding to CD36. We observed highly increased expression of specific var genes encoding PfEMP1s in all CD36-binding transfectants. These results suggest that ectopic vir expression regulates var expression through a yet unknown mechanism. In conclusion, the observed cytoadhesion of P. falciparum expressing vir genes depended on PfEMP1s, making this experimental unsuitable for characterizing VIR proteins.
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Affiliation(s)
- Torben Rehn
- Bernhard Nocht Institute for Tropical Medicine, 20359 Hamburg, Germany; (T.R.); (P.L.); (T.H.T.N.); (E.P.); (M.S.); (L.K.R.); (J.B.); (D.C.); (N.G.M.)
| | - Pedro Lubiana
- Bernhard Nocht Institute for Tropical Medicine, 20359 Hamburg, Germany; (T.R.); (P.L.); (T.H.T.N.); (E.P.); (M.S.); (L.K.R.); (J.B.); (D.C.); (N.G.M.)
| | - Thi Huyen Trang Nguyen
- Bernhard Nocht Institute for Tropical Medicine, 20359 Hamburg, Germany; (T.R.); (P.L.); (T.H.T.N.); (E.P.); (M.S.); (L.K.R.); (J.B.); (D.C.); (N.G.M.)
| | - Eva Pansegrau
- Bernhard Nocht Institute for Tropical Medicine, 20359 Hamburg, Germany; (T.R.); (P.L.); (T.H.T.N.); (E.P.); (M.S.); (L.K.R.); (J.B.); (D.C.); (N.G.M.)
| | - Marius Schmitt
- Bernhard Nocht Institute for Tropical Medicine, 20359 Hamburg, Germany; (T.R.); (P.L.); (T.H.T.N.); (E.P.); (M.S.); (L.K.R.); (J.B.); (D.C.); (N.G.M.)
| | - Lisa Katharina Roth
- Bernhard Nocht Institute for Tropical Medicine, 20359 Hamburg, Germany; (T.R.); (P.L.); (T.H.T.N.); (E.P.); (M.S.); (L.K.R.); (J.B.); (D.C.); (N.G.M.)
| | - Jana Brehmer
- Bernhard Nocht Institute for Tropical Medicine, 20359 Hamburg, Germany; (T.R.); (P.L.); (T.H.T.N.); (E.P.); (M.S.); (L.K.R.); (J.B.); (D.C.); (N.G.M.)
| | - Thomas Roeder
- Molecular Physiology Department, Zoological Institute, Christian-Albrechts University Kiel, 24118 Kiel, Germany;
- Airway Research Center North (ARCN), German Center for Lung Research (DZL), 24118 Kiel, Germany
| | - Dániel Cadar
- Bernhard Nocht Institute for Tropical Medicine, 20359 Hamburg, Germany; (T.R.); (P.L.); (T.H.T.N.); (E.P.); (M.S.); (L.K.R.); (J.B.); (D.C.); (N.G.M.)
| | - Nahla Galal Metwally
- Bernhard Nocht Institute for Tropical Medicine, 20359 Hamburg, Germany; (T.R.); (P.L.); (T.H.T.N.); (E.P.); (M.S.); (L.K.R.); (J.B.); (D.C.); (N.G.M.)
| | - Iris Bruchhaus
- Bernhard Nocht Institute for Tropical Medicine, 20359 Hamburg, Germany; (T.R.); (P.L.); (T.H.T.N.); (E.P.); (M.S.); (L.K.R.); (J.B.); (D.C.); (N.G.M.)
- Department of Biology, University of Hamburg, 22601 Hamburg, Germany
- Correspondence:
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Identifying Targets of Protective Antibodies against Severe Malaria in Papua, Indonesia, Using Locally Expressed Domains of Plasmodium falciparum Erythrocyte Membrane Protein 1. Infect Immun 2022; 90:e0043521. [PMID: 34871039 PMCID: PMC8853675 DOI: 10.1128/iai.00435-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1), a diverse family of multidomain proteins expressed on the surface of malaria-infected erythrocytes, is an important target of protective immunity against malaria. Our group recently studied transcription of the var genes encoding PfEMP1 in individuals from Papua, Indonesia, with severe or uncomplicated malaria. We cloned and expressed domains from 32 PfEMP1s, including 22 that were upregulated in severe malaria and 10 that were upregulated in uncomplicated malaria, using a wheat germ cell-free expression system. We used Luminex technology to measure IgG antibodies to these 32 domains and control proteins in 63 individuals (11 children). At presentation to hospital, levels of antibodies to PfEMP1 domains were either higher in uncomplicated malaria or were not significantly different between groups. Using principal component analysis, antibodies to 3 of 32 domains were highly discriminatory between groups. These included two domains upregulated in severe malaria, a DBLβ13 domain and a CIDRα1.6 domain (which has been previously implicated in severe malaria pathogenesis), and a DBLδ domain that was upregulated in uncomplicated malaria. Antibody to control non-PfEMP1 antigens did not differ with disease severity. Antibodies to PfEMP1 domains differ with malaria severity. Lack of antibodies to locally expressed PfEMP1 types, including both domains previously associated with severe malaria and newly identified targets, may in part explain malaria severity in Papuan adults.
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20
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Alteration of the expression of sirtuins and var genes by heat shock in the malaria parasite Plasmodium falciparum. Mol Biochem Parasitol 2022; 248:111458. [PMID: 35031386 DOI: 10.1016/j.molbiopara.2022.111458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 12/27/2021] [Accepted: 01/10/2022] [Indexed: 11/22/2022]
Abstract
BACKGROUND In Plasmodium falciparum the monoallelic expression of var virulence genes is regulated through epigenetic mechanisms. A study in the Gambia showed that an increase in var gene expression is associated with fever, high blood lactate with commonly-expressed var genes expressed in patients with severe malaria. A strong association was demonstrated between the upregulation of PfSir2A and group B var genes. A subsequent study in Kenya extended this association to show a link between elevated expression of PfSir2A and overall var transcript levels. We investigate here the link between heat shock and/or lactate levels on sirtuin and var gene expression levels in vitro. METHODS In vitro experiments were conducted using laboratory and recently-laboratory-adapted Kenyan isolates of P. falciparum. To investigate a potential cause-and-effect relationship between host stress factors and parasite gene expression, qPCR was used to measure the expression of sirtuins and var genes after highly synchronous cultured parasites had been exposed to 2 h or 6 h of heat shock at 40 °C or elevated lactate. RESULTS Heat shock was shown to increase the expression ofPfSir2B in the trophozoites, whereas exposure to lactate was not. After the ring stages were exposed to heat shock and lactate, there was no alteration in the expression of sirtuins and severe-disease-associated upsA and upsB var genes. The association between high blood lactate and sirtuin/var gene expression that was previously observed in vivo appears to be coincidental rather than causative. CONCLUSIONS This study demonstrates that heat stress in a laboratory and recently-laboratory-adapted isolates of P. falciparum results in a small increase in PfSir2B transcripts in the trophozoite stages only. This finding adds to our understanding of how patient factors can influence the outcome of Plasmodium falciparum infections.
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21
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Sahu PK, Duffy FJ, Dankwa S, Vishnyakova M, Majhi M, Pirpamer L, Vigdorovich V, Bage J, Maharana S, Mandala W, Rogerson SJ, Seydel KB, Taylor TE, Kim K, Sather DN, Mohanty A, Mohanty RR, Mohanty A, Pattnaik R, Aitchison JD, Hoffman A, Mohanty S, Smith JD, Bernabeu M, Wassmer SC. Determinants of brain swelling in pediatric and adult cerebral malaria. JCI Insight 2021; 6:145823. [PMID: 34549725 PMCID: PMC8492338 DOI: 10.1172/jci.insight.145823] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Accepted: 07/28/2021] [Indexed: 01/08/2023] Open
Abstract
Cerebral malaria (CM) affects children and adults, but brain swelling is more severe in children. To investigate features associated with brain swelling in malaria, we performed blood profiling and brain MRI in a cohort of pediatric and adult patients with CM in Rourkela, India, and compared them with an African pediatric CM cohort in Malawi. We determined that higher plasma Plasmodium falciparum histidine rich protein 2 (PfHRP2) levels and elevated var transcripts that encode for binding to endothelial protein C receptor (EPCR) were linked to CM at both sites. Machine learning models trained on the African pediatric cohort could classify brain swelling in Indian children CM cases but had weaker performance for adult classification, due to overall lower parasite var transcript levels in this age group and more severe thrombocytopenia in Rourkela adults. Subgrouping of patients with CM revealed higher parasite biomass linked to severe thrombocytopenia and higher Group A–EPCR var transcripts in mild thrombocytopenia. Overall, these findings provide evidence that higher parasite biomass and a subset of Group A–EPCR binding variants are common features in children and adult CM cases, despite age differences in brain swelling.
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Affiliation(s)
- Praveen K Sahu
- Center for the Study of Complex Malaria in India, Ispat General Hospital (IGH), Rourkela, Odisha, India
| | - Fergal J Duffy
- Seattle Children's Research Institute, Seattle, Washington, USA
| | - Selasi Dankwa
- Seattle Children's Research Institute, Seattle, Washington, USA
| | | | | | - Lukas Pirpamer
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | | | - Jabamani Bage
- Center for the Study of Complex Malaria in India, Ispat General Hospital (IGH), Rourkela, Odisha, India
| | - Sameer Maharana
- Center for the Study of Complex Malaria in India, Ispat General Hospital (IGH), Rourkela, Odisha, India
| | - Wilson Mandala
- Malawi University of Science and Technology, Limbe, Malawi
| | - Stephen J Rogerson
- Department of Medicine, The Doherty Institute, University of Melbourne, Melbourne, Australia
| | - Karl B Seydel
- Department of Osteopathic Medical Specialties, College of Osteopathic Medicine, Michigan State University, East Lansing, Michigan, USA.,Blantyre Malaria Project, Kamuzu University of Health Sciences, Blantyre, Malawi
| | - Terrie E Taylor
- Department of Osteopathic Medical Specialties, College of Osteopathic Medicine, Michigan State University, East Lansing, Michigan, USA.,Blantyre Malaria Project, Kamuzu University of Health Sciences, Blantyre, Malawi
| | - Kami Kim
- Division of Infectious Diseases and International Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
| | - D Noah Sather
- Seattle Children's Research Institute, Seattle, Washington, USA.,Department of Pediatrics, University of Washington, Seattle, Washington, USA
| | - Akshaya Mohanty
- Infectious Diseases Biology Unit, Institute of Life Sciences, Bhubaneswar, Odisha, India
| | | | - Anita Mohanty
- Department of Intensive Care, IGH, Rourkela, Odisha, India
| | | | - John D Aitchison
- Seattle Children's Research Institute, Seattle, Washington, USA.,Department of Pediatrics, University of Washington, Seattle, Washington, USA
| | - Angelika Hoffman
- Department of Neuroradiology, University Hospital Heidelberg, Heidelberg, Germany.,University Institute of Diagnostic and Interventional Neuroradiology, University Hospital Bern, Inselspital, University of Bern, Switzerland
| | - Sanjib Mohanty
- Center for the Study of Complex Malaria in India, Ispat General Hospital (IGH), Rourkela, Odisha, India
| | - Joseph D Smith
- Seattle Children's Research Institute, Seattle, Washington, USA.,Department of Pediatrics, University of Washington, Seattle, Washington, USA
| | - Maria Bernabeu
- Seattle Children's Research Institute, Seattle, Washington, USA.,European Molecular Biology Laboratory (EMBL), Barcelona, Spain
| | - Samuel C Wassmer
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, United Kingdom
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22
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Computational Insights into the Interaction between Cytoadherence Receptor gC1qR and the DBLβ12 Domain of a Plasmodium falciparum PfEMP1 Ligand. Life (Basel) 2021; 11:life11090993. [PMID: 34575142 PMCID: PMC8471399 DOI: 10.3390/life11090993] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 09/09/2021] [Accepted: 09/15/2021] [Indexed: 12/30/2022] Open
Abstract
Human receptor gC1qR is a 32 kD protein that mediates the cytoadherence of Plasmodium falciparum-infected erythrocytes (IEs) to human brain microvascular endothelial cells (HBMEC) and platelets. The cytoadherence of IEs to gC1qR has been associated with severe malaria symptoms. The cytoadherence to gC1qR is mediated by the Duffy binding-like β12 (DBLβ12) domain of Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1), PFD0020c. Here, we report the structural insights into the binding of the DBLβ12 domain of PfEMP1 with the human receptor gC1qR using computational methods. A molecular model of the DBLβ12 domain was generated and used for protein-protein docking with the host receptor gC1qR. The protein-protein docking revealed that the DBLβ12 asymmetrically interacts with two subunits of the gC1qR trimer at the solution face of gC1qR. A total of 21 amino acid residues of DBLβ12 interact with 26 amino acid residues in the gC1qR trimer through 99 nonbonding interactions and 4 hydrogen bonds. Comparative analysis of binding sites on the DBL domain fold for the two receptors gC1qR and ICAM1 showed that the two sites are distinct. This is the first study that provides structural insights into DBLβ12 binding with its receptor gC1qR and may help in designing novel antisevere malaria interventions.
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23
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Chaudhry S, Singh V. A systematic review on genetic diversity of var gene DBL1α domain from different geographical regions in Plasmodium falciparum isolates. INFECTION GENETICS AND EVOLUTION 2021; 95:105049. [PMID: 34450294 DOI: 10.1016/j.meegid.2021.105049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 08/16/2021] [Accepted: 08/20/2021] [Indexed: 11/26/2022]
Abstract
Background The major variant surface antigen (VSA) in Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) encoded by var gene family has an important role in cytoadhesion/sequestration and rosetting by adhesion of uninfected erythrocytes to infected erythrocytes leading to disease severity. DBL1α domain in the PfEMP-1, protein is crucial in the cytoadhesion phenomena in P. falciparum infections and this review aims to analyse the genetic diversity of DBL1α domain sequences in PfEMP-1 from different geographical regions globally. Methods All available DBL1α sequence data was reviewed by using the electronic database PubMed, ResearchGate, Google, Google scholar, MEDLINE with the following Keywords-Plasmodium falciparum", "var gene", "DBL1α", "field isolate", "diversity", "polymorphism", "Africa", "America", "Asia" and "Caribbean" from different geographical regions across the world. Results A total of 240 studies were identified initially but only 20 studies qualified for this systematic review. The overall ratio of distinct sequences DBL1α domain was 24.62/1167 the highest in African region (33.59/766 isolates) and lowest in South America (5.6/215 isolates). In the 18 included studies, the presence of distinct DBL1α sequences was the highest in Oceania 55.32% (1186/2144) followed by Africa (38.43%), Asia (22.45%) and South America (16.48%), though the sample size in Oceania was comparatively smaller to that of Africa and South America. Conclusion This review highlights the ratio and percentage of distinct sequences of DBL1α domain of var gene in different geographical regions giving an idea of the existing diversity prevalent in this potential vaccine target gene which may contribute to designing the preventive measures towards disease severity.
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Affiliation(s)
- Shewta Chaudhry
- Cell Biology Laboratory and Malaria Parasite Bank, ICMR-National Institute of Malaria Research, New Delhi, India
| | - Vineeta Singh
- Cell Biology Laboratory and Malaria Parasite Bank, ICMR-National Institute of Malaria Research, New Delhi, India.
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24
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Gross MR, Hsu R, Deitsch KW. Evolution of transcriptional control of antigenic variation and virulence in human and ape malaria parasites. BMC Ecol Evol 2021; 21:139. [PMID: 34238209 PMCID: PMC8265125 DOI: 10.1186/s12862-021-01872-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Accepted: 07/02/2021] [Indexed: 11/13/2022] Open
Abstract
Background The most severe form of human malaria is caused by the protozoan parasite Plasmodium falciparum. This unicellular organism is a member of a subgenus of Plasmodium called the Laverania that infects apes, with P. falciparum being the only member that infects humans. The exceptional virulence of this species to humans can be largely attributed to a family of variant surface antigens placed by the parasites onto the surface of infected red blood cells that mediate adherence to the vascular endothelium. These proteins are encoded by a large, multicopy gene family called var, with each var gene encoding a different form of the protein. By changing which var gene is expressed, parasites avoid immune recognition, a process called antigenic variation that underlies the chronic nature of malaria infections. Results Here we show that the common ancestor of the branch of the Laverania lineage that includes the human parasite underwent a remarkable change in the organization and structure of elements linked to the complex transcriptional regulation displayed by the var gene family. Unlike the other members of the Laverania, the clade that gave rise to P. falciparum evolved distinct subsets of var genes distinguishable by different upstream transcriptional regulatory regions that have been associated with different expression profiles and virulence properties. In addition, two uniquely conserved var genes that have been proposed to play a role in coordinating transcriptional switching similarly arose uniquely within this clade. We hypothesize that these changes originated at a time of dramatic climatic change on the African continent that is predicted to have led to significant changes in transmission dynamics, thus selecting for patterns of antigenic variation that enabled lengthier, more chronic infections. Conclusions These observations suggest that changes in transmission dynamics selected for significant alterations in the transcriptional regulatory mechanisms that mediate antigenic variation in the parasite lineage that includes P. falciparum. These changes likely underlie the chronic nature of these infections as well as their exceptional virulence. Supplementary Information The online version contains supplementary material available at 10.1186/s12862-021-01872-z.
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Affiliation(s)
- Mackensie R Gross
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, NY, USA
| | - Rosie Hsu
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, NY, USA
| | - Kirk W Deitsch
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, NY, USA.
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Prusty D, Gupta N, Upadhyay A, Dar A, Naik B, Kumar N, Prajapati VK. Asymptomatic malaria infection prevailing risks for human health and malaria elimination. INFECTION GENETICS AND EVOLUTION 2021; 93:104987. [PMID: 34216796 DOI: 10.1016/j.meegid.2021.104987] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 06/23/2021] [Accepted: 06/27/2021] [Indexed: 01/09/2023]
Abstract
There has been a consistent rise in malaria cases in the last few years. The existing malaria control measures are challenged by insecticide resistance in the mosquito vector, drug résistance in parasite populations, and asymptomatic malaria (ASM) in healthy individuals. The absence of apparent malaria symptoms and the presence of low parasitemia makes ASM a hidden reservoir for malaria transmission and an impediment in malaria elimination efforts. This review focuses on ASM in malaria-endemic countries and the past and present research trends from those geographical locations. The harmful impacts of asymptomatic malaria on human health and its contribution to disease transmission are highlighted. We discuss certain crucial genetic changes in the parasite and host immune response necessary for maintaining low parasitemia leading to long-term parasite survival in the host. Since the chronic health effects and the potential roles for disease transmission of ASM remain mostly unknown to significant populations, we offer proposals for developing general awareness. We also suggest advanced technology-based diagnostic methods, and treatment strategies to eliminate ASM.
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Affiliation(s)
- Dhaneswar Prusty
- Department of Biochemistry, School of Life Sciences, Central University of Rajasthan, Bandarsindri, Kishangarh, Ajmer, 305817, Rajasthan, India.
| | - Nidhi Gupta
- Department of Biochemistry, School of Life Sciences, Central University of Rajasthan, Bandarsindri, Kishangarh, Ajmer, 305817, Rajasthan, India
| | - Arun Upadhyay
- Department of Biochemistry, School of Life Sciences, Central University of Rajasthan, Bandarsindri, Kishangarh, Ajmer, 305817, Rajasthan, India
| | - Ashraf Dar
- Department of Biochemistry, University of Kashmir, Hazaratbal, Srinagar 190006, Jammu and Kashmir, India
| | - Biswajit Naik
- Department of Biochemistry, School of Life Sciences, Central University of Rajasthan, Bandarsindri, Kishangarh, Ajmer, 305817, Rajasthan, India
| | - Navin Kumar
- School of Biotechnology, Gautam Buddha University, Greater Noida, 201308, UP, India
| | - Vijay Kumar Prajapati
- Department of Biochemistry, School of Life Sciences, Central University of Rajasthan, Bandarsindri, Kishangarh, Ajmer, 305817, Rajasthan, India
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Cubillos EFG, Prata IO, Fotoran WL, Ranford-Cartwright L, Wunderlich G. The Transcription Factor PfAP2-O Influences Virulence Gene Transcription and Sexual Development in Plasmodium falciparum. Front Cell Infect Microbiol 2021; 11:669088. [PMID: 34268135 PMCID: PMC8275450 DOI: 10.3389/fcimb.2021.669088] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Accepted: 04/23/2021] [Indexed: 12/02/2022] Open
Abstract
The human malaria parasite Plasmodium falciparum expresses variant PfEMP1 proteins on the infected erythrocyte, which function as ligands for endothelial receptors in capillary vessels, leading to erythrocyte sequestration and severe malaria. The factors that orchestrate the mono-allelic expression of the 45–90 PfEMP1-encoding var genes within each parasite genome are still not fully identified. Here, we show that the transcription factor PfAP2-O influences the transcription of var genes. The temporary knockdown of PfAP2-O leads to a complete loss of var transcriptional memory and a decrease in cytoadherence in CD36 adherent parasites. AP2-O-knocked-down parasites exhibited also significant reductions in transmission through Anopheles mosquitoes. We propose that PfAP2-O is, beside its role in transmission stages, also one of the virulence gene transcriptional regulators and may therefore be exploited as an important target to disrupt severe malaria and block parasite transmission.
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Affiliation(s)
- Eliana F G Cubillos
- Department of Parasitology, Institute for Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Isadora Oliveira Prata
- Department of Parasitology, Institute for Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Wesley Luzetti Fotoran
- Department of Parasitology, Institute for Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Lisa Ranford-Cartwright
- Institute of Biodiversity, Animal Health & Comparative Medicine, College of Medical, Veterinary and Life Science, University of Glasgow, Glasgow, United Kingdom
| | - Gerhard Wunderlich
- Department of Parasitology, Institute for Biomedical Sciences, University of São Paulo, São Paulo, Brazil
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27
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Antibody Levels to Plasmodium falciparum Erythrocyte Membrane Protein 1-DBLγ11 and DBLδ-1 Predict Reduction in Parasite Density. mSystems 2021; 6:e0034721. [PMID: 34128693 PMCID: PMC8269226 DOI: 10.1128/msystems.00347-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) is a variant surface antigen family expressed on infected red blood cells that plays a role in immune evasion and mediates adhesion to vascular endothelium. PfEMP1s are potential targets of protective antibodies as suggested by previous seroepidemiology studies. Here, we used previously reported proteomic analyses of PfEMP1s of clinical parasite isolates collected from Malian children to identify targets of immunity. We designed a peptide library representing 11 PfEMP1 domains commonly identified on clinical isolates by membrane proteomics and then examined peptide-specific antibody responses in Malian children. The number of previous malaria infections was associated with development of PfEMP1 antibodies to peptides from domains CIDRα1.4, DBLγ11, DBLβ3, and DBLδ1. A zero-inflated negative binomial model with random effects (ZINBRE) was used to identify peptide reactivities that were associated with malaria risk. This peptide selection and serosurvey strategy revealed that high antibody levels to peptides from DBLγ11 and DBLδ1 domains correlated with decreased parasite burden in future infections, supporting the notion that specific PfEMP1 domains play a role in protective immunity. IMPORTANCEPlasmodium infection causes devastating disease and high mortality in young children. Immunity develops progressively as children acquire protection against severe disease, although reinfections and recrudescences still occur throughout life in areas of endemicity, partly due to parasite immunoevasion via switching of variant proteins such as Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) expressed on the infected erythrocyte surface. Understanding the mechanisms behind antibody protection can advance development of new therapeutic interventions that address this challenge. PfEMP1 domain-specific antibodies have been linked to reduction in severe malaria; however, the large diversity of PfEMP1 domains in circulating parasites has not been fully investigated. We designed representative peptides based on B cell epitopes of PfEMP1 domains identified in membranes of clinical parasite isolates and surveyed peptide-specific antibody responses among young Malian children in a longitudinal birth cohort. We examined previous infections and age as factors contributing to antibody acquisition and identified antibody specificities that predict malaria risk.
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28
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Petersen JEV, Saelens JW, Freedman E, Turner L, Lavstsen T, Fairhurst RM, Diakité M, Taylor SM. Sickle-trait hemoglobin reduces adhesion to both CD36 and EPCR by Plasmodium falciparum-infected erythrocytes. PLoS Pathog 2021; 17:e1009659. [PMID: 34115805 PMCID: PMC8221791 DOI: 10.1371/journal.ppat.1009659] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 06/23/2021] [Accepted: 05/20/2021] [Indexed: 01/01/2023] Open
Abstract
Sickle-trait hemoglobin protects against severe Plasmodium falciparum malaria. Severe malaria is governed in part by the expression of the Plasmodium falciparum Erythrocyte Membrane Protein 1 (PfEMP1) that are encoded by var genes, specifically those variants that bind Endothelial Protein C Receptor (EPCR). In this study, we investigate the effect of sickle-trait on parasite var gene expression and function in vitro and in field-collected parasites. We mapped var gene reads generated from RNA sequencing in parasite cultures in normal and sickle-cell trait blood throughout the asexual lifecycle. We investigated sickle-trait effect on PfEMP1 interactions with host receptors CD36 and EPCR using static adhesion assays and flow cytometry. Var expression in vivo was compared by assembling var domains sequenced from total RNA in parasites infecting Malian children with HbAA and HbAS. Sickle-trait did not alter the abundance or type of var gene transcripts in vitro, nor the abundance of overall transcripts or of var functional domains in vivo. In adhesion assays using recombinant host receptors, sickle-trait reduced adhesion by 73-86% to CD36 and 83% to EPCR. Similarly, sickle-trait reduced the surface expression of EPCR-binding PfEMP1. In conclusion, Sickle-cell trait does not directly affect var gene transcription but does reduce the surface expression and function of PfEMP1. This provides a direct mechanism for protection against severe malaria conferred by sickle-trait hemoglobin. Trial Registration: ClinicalTrials.gov Identifier: NCT02645604.
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Affiliation(s)
- Jens E. V. Petersen
- Division of Infectious Diseases, Duke University School of Medicine, Durham, North Carolina, United States of America
- * E-mail:
| | - Joseph W. Saelens
- Division of Infectious Diseases, Duke University School of Medicine, Durham, North Carolina, United States of America
| | - Elizabeth Freedman
- Division of Infectious Diseases, Duke University School of Medicine, Durham, North Carolina, United States of America
| | - Louise Turner
- Centre for Medical Parasitology, University of Copenhagen, Copenhagen, Denmark
| | - Thomas Lavstsen
- Centre for Medical Parasitology, University of Copenhagen, Copenhagen, Denmark
| | - Rick M. Fairhurst
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Mahamadou Diakité
- Malaria Research and Training Center, University of Sciences, Techniques, and Technologies of Bamako, Bamako, Mali
| | - Steve M. Taylor
- Division of Infectious Diseases, Duke University School of Medicine, Durham, North Carolina, United States of America
- Duke Global Health Institute, Duke University, Durham, North Carolina, United States of America
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The role of upstream open reading frames in translation regulation in the apicomplexan parasites Plasmodium falciparum and Toxoplasma gondii. Parasitology 2021; 148:1277-1287. [PMID: 34099078 PMCID: PMC8383288 DOI: 10.1017/s0031182021000937] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
During their complex life cycles, the Apicomplexan parasites Plasmodium falciparum and Toxoplasma gondii employ several layers of regulation of their gene expression. One such layer is mediated at the level of translation through upstream open reading frames (uORFs). As uORFs are found in the upstream regions of a majority of transcripts in both the parasites, it is essential that their roles in translational regulation be appreciated to a greater extent. This review provides a comprehensive summary of studies that show uORF-mediated gene regulation in these parasites and highlights examples of clinically and physiologically relevant genes, including var2csa in P. falciparum, and ApiAT1 in T. gondii, that exhibit uORF-mediated regulation. In addition to these examples, several studies that use bioinformatics, transcriptomics, proteomics and ribosome profiling also indicate the possibility of widespread translational regulation by uORFs. Further analysis of these genome-wide datasets, taking into account uORFs associated with each gene, will reveal novel genes involved in key biological pathways such as cell-cycle progression, stress-response and pathogenicity. The cumulative evidence from studies presented in this review suggests that uORFs will play crucial roles in regulating gene expression during clinical disease caused by these important human pathogens.
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Rachmania S, Sulistyaningsih E, Ratna Dewi AAI. Recombinant DBL2β-PfEMP1 of the Indonesian Plasmodium falciparum induces immune responses in Wistar rats. J Taibah Univ Med Sci 2021; 16:422-430. [PMID: 34140870 PMCID: PMC8178645 DOI: 10.1016/j.jtumed.2020.12.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 12/12/2020] [Accepted: 12/17/2020] [Indexed: 11/21/2022] Open
Abstract
OBJECTIVES The Duffy binding-like (DBL) domain of the Plasmodium falciparum Erythrocyte Membrane Protein 1 (PfEMP1) is reportedly responsible for the pathophysiology of cerebral malaria. People living in endemic malaria areas possess specific antibodies against PfEMP1 and elicit immune responses to control the severity of malaria infection. Therefore, PfEMP1 may be a potential protein-based vaccine candidate. This study aimed to explore the humoral and cellular immune responses induced by the recombinant DBL2β-PfEMP1 obtained from the Indonesian P. falciparum isolate. METHODS The recombinant protein was expressed in Escherichia coli BL21(DE3) as soluble and insoluble fractions, and this protein was purified using affinity chromatography before administration as a subcutaneous injection in Wistar rats on days 1, 21, and 42. Sera were harvested 14 days after the second and third injections to determine the titre of IgG and the concentration of CD4+ cells using the enzyme linked immunosorbent assay (ELISA). RESULTS The IgG titre and the CD4+ cell concentration were found to be increased after the second and third injections. The Mann-Whitney test results showed a significant difference between the control and treatment groups for both the IgG and CD4+ cells (p = 0.001 and p = 0.000, respectively). Western blotting results indicated the presence of a specific antibody against the recombinant DBL2β-PfEMP1. CONCLUSIONS The recombinant DBL2β-PfEMP1 of the Indonesian P. falciparum isolate could induce humoral and cellular immune responses. Further studies on IgG exerting inhibitory effects and the role of CD4+ cells and their association with other effector cells are essential to determine the efficacy of DBL2β-PfEMP1 and its potential application as a peptide-based malaria vaccine candidate.
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Affiliation(s)
- Sheilla Rachmania
- Department of Histology, Faculty of Medicine, University of Jember, Indonesia
| | - Erma Sulistyaningsih
- Department of Parasitology, Faculty of Medicine, University of Jember, Indonesia
| | - Anak Agung I. Ratna Dewi
- Department of Chemistry, Faculty of Mathematics and Natural Sciences, University of Jember, Indonesia
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31
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Wichers JS, Tonkin-Hill G, Thye T, Krumkamp R, Kreuels B, Strauss J, von Thien H, Scholz JAM, Smedegaard Hansson H, Weisel Jensen R, Turner L, Lorenz FR, Schöllhorn A, Bruchhaus I, Tannich E, Fendel R, Otto TD, Lavstsen T, Gilberger TW, Duffy MF, Bachmann A. Common virulence gene expression in adult first-time infected malaria patients and severe cases. eLife 2021; 10:e69040. [PMID: 33908865 PMCID: PMC8102065 DOI: 10.7554/elife.69040] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 04/18/2021] [Indexed: 12/22/2022] Open
Abstract
Sequestration of Plasmodium falciparum(P. falciparum)-infected erythrocytes to host endothelium through the parasite-derived P. falciparum erythrocyte membrane protein 1 (PfEMP1) adhesion proteins is central to the development of malaria pathogenesis. PfEMP1 proteins have diversified and expanded to encompass many sequence variants, conferring each parasite a similar array of human endothelial receptor-binding phenotypes. Here, we analyzed RNA-seq profiles of parasites isolated from 32 P. falciparum-infected adult travellers returning to Germany. Patients were categorized into either malaria naive (n = 15) or pre-exposed (n = 17), and into severe (n = 8) or non-severe (n = 24) cases. For differential expression analysis, PfEMP1-encoding var gene transcripts were de novo assembled from RNA-seq data and, in parallel, var-expressed sequence tags were analyzed and used to predict the encoded domain composition of the transcripts. Both approaches showed in concordance that severe malaria was associated with PfEMP1 containing the endothelial protein C receptor (EPCR)-binding CIDRα1 domain, whereas CD36-binding PfEMP1 was linked to non-severe malaria outcomes. First-time infected adults were more likely to develop severe symptoms and tended to be infected for a longer period. Thus, parasites with more pathogenic PfEMP1 variants are more common in patients with a naive immune status, and/or adverse inflammatory host responses to first infections favor the growth of EPCR-binding parasites.
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Affiliation(s)
- J Stephan Wichers
- Molecular Biology and Immunology, Bernhard Nocht Institute for Tropical MedicineHamburgGermany
- Centre for Structural Systems BiologyHamburgGermany
- Biology Department, University of HamburgHamburgGermany
| | | | - Thorsten Thye
- Epidemiology and Diagnostics, Bernhard Nocht Institute for Tropical MedicineHamburgGermany
| | - Ralf Krumkamp
- Epidemiology and Diagnostics, Bernhard Nocht Institute for Tropical MedicineHamburgGermany
- German Center for Infection Research (DZIF), Partner Site Hamburg-Lübeck-Borstel-RiemsHamburgGermany
| | - Benno Kreuels
- Department of Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine, GermanyHamburgGermany
- Department of Medicine, College of MedicineBlantyreMalawi
- Department of Medicine, University Medical Center Hamburg-EppendorfHamburgGermany
| | - Jan Strauss
- Molecular Biology and Immunology, Bernhard Nocht Institute for Tropical MedicineHamburgGermany
- Centre for Structural Systems BiologyHamburgGermany
- Biology Department, University of HamburgHamburgGermany
| | - Heidrun von Thien
- Molecular Biology and Immunology, Bernhard Nocht Institute for Tropical MedicineHamburgGermany
- Centre for Structural Systems BiologyHamburgGermany
- Biology Department, University of HamburgHamburgGermany
| | - Judith AM Scholz
- Molecular Biology and Immunology, Bernhard Nocht Institute for Tropical MedicineHamburgGermany
| | | | | | | | | | - Anna Schöllhorn
- Institute of Tropical Medicine, University of TübingenTübingenGermany
| | - Iris Bruchhaus
- Molecular Biology and Immunology, Bernhard Nocht Institute for Tropical MedicineHamburgGermany
- Biology Department, University of HamburgHamburgGermany
| | - Egbert Tannich
- Epidemiology and Diagnostics, Bernhard Nocht Institute for Tropical MedicineHamburgGermany
- German Center for Infection Research (DZIF), Partner Site Hamburg-Lübeck-Borstel-RiemsHamburgGermany
| | - Rolf Fendel
- Institute of Tropical Medicine, University of TübingenTübingenGermany
- German Center for Infection Research (DZIF), Partner Site TübingenTübingenGermany
| | - Thomas D Otto
- Institute of Infection, Immunity and Inflammation, University of GlasgowGlasgowUnited Kingdom
| | | | - Tim W Gilberger
- Molecular Biology and Immunology, Bernhard Nocht Institute for Tropical MedicineHamburgGermany
- Centre for Structural Systems BiologyHamburgGermany
- Biology Department, University of HamburgHamburgGermany
| | - Michael F Duffy
- Department of Microbiology and Immunology, University of MelbourneMelbourneAustralia
| | - Anna Bachmann
- Molecular Biology and Immunology, Bernhard Nocht Institute for Tropical MedicineHamburgGermany
- Centre for Structural Systems BiologyHamburgGermany
- Biology Department, University of HamburgHamburgGermany
- German Center for Infection Research (DZIF), Partner Site Hamburg-Lübeck-Borstel-RiemsHamburgGermany
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32
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Childs LM, Larremore DB. Network Models for Malaria: Antigens, Dynamics, and Evolution Over Space and Time. SYSTEMS MEDICINE 2021. [DOI: 10.1016/b978-0-12-801238-3.11512-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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33
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Zhang X, Deitsch KW, Kirkman LA. The contribution of extrachromosomal DNA to genome plasticity in malaria parasites. Mol Microbiol 2020; 115:503-507. [PMID: 33103309 DOI: 10.1111/mmi.14632] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 10/19/2020] [Accepted: 10/19/2020] [Indexed: 01/20/2023]
Abstract
Malaria caused by the protozoan parasite Plasmodium falciparum continues to impose significant morbidity and mortality, despite substantial investment into drug and vaccine development and deployment. Underlying the resilience of this parasite is its remarkable ability to undergo genome modifications, thus, providing parasite populations with extensive genetic variability that accelerates selection of drug resistance and limits the efficacy of most vaccines. This genome plasticity is rooted in the mechanisms of DNA repair that parasites employ to maintain genome integrity, a process skewed toward homologous recombination through the evolutionary loss of classical nonhomologous end joining. Repair of DNA double-strand breaks have been shown to enable "shuffling" of antigen-encoding gene sequences to vastly increase antigen diversity and to enable copy number expansion of genes that contribute to drug resistance. The latter phenomenon has been proposed to be a major contributor to the rise of resistance to several classes of antimalarial drugs. In this issue of Molecular Microbiology, McDaniels and colleagues add yet another mechanism that malaria parasites use to reduce drug susceptibility by demonstrating that P. falciparum can maintain expanded arrays of drug resistance cassettes as stably replicating, circular, extrachromosomal DNAs, thus, expanding genome plasticity beyond the parasite's 14 nuclear chromosomes.
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Affiliation(s)
- Xu Zhang
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, NY, USA
| | - Kirk W Deitsch
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, NY, USA
| | - Laura A Kirkman
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, NY, USA.,Department of Internal Medicine, Division of Infectious Diseases, Weill Cornell Medical College, New York, NY, USA
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34
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Abstract
PfEMP1 is the major antigen involved in Plasmodium falciparum-infected erythrocyte sequestration in cerebrovascular endothelium. While some PfEMP1 domains have been associated with clinical phenotypes of malaria, formal associations between the expression of a specific domain and the adhesion properties of clinical isolates are limited. In this context, 73 cerebral malaria (CM) and 98 uncomplicated malaria (UM) Beninese children were recruited. We attempted to correlate the cytoadherence phenotype of Plasmodium falciparum isolates with the clinical presentation and the expression of specific PfEMP1 domains. Cytoadherence level on Hbec-5i and CHO-ICAM-1 cell lines and var genes expression were measured. We also investigated the prevalence of the ICAM-1-binding amino acid motif and dual receptor-binding domains, described as a potential determinant of cerebral malaria pathophysiology. We finally evaluated IgG levels against PfEMP1 recombinant domains (CIDRα1.4, DBLβ3, and CIDRα1.4-DBLβ3). CM isolates displayed higher cytoadherence levels on both cell lines, and we found a correlation between CIDRα1.4-DBLβ1/3 domain expression and CHO-ICAM-1 cytoadherence level. Endothelial protein C receptor (EPCR)-binding domains were overexpressed in CM isolates compared to UM whereas no difference was found in ICAM-1-binding DBLβ1/3 domain expression. Surprisingly, both CM and UM isolates expressed ICAM-1-binding motif and dual receptor-binding domains. There was no difference in IgG response against DBLβ3 between CM and UM isolates expressing ICAM-1-binding DBLβ1/3 domain. It raises questions about the role of this motif in CM pathophysiology, and further studies are needed, especially on the role of DBLβ1/3 without the ICAM-1-binding motif.IMPORTANCE Cerebral malaria pathophysiology remains unknown despite extensive research. PfEMP1 proteins have been identified as the main Plasmodium antigen involved in cerebrovascular endothelium sequestration, but it is unclear which var gene domain is involved in Plasmodium cytoadhesion. EPCR binding is a major determinant of cerebral malaria whereas the ICAM-1-binding role is still questioned. Our study confirmed the EPCR-binding role in CM pathophysiology with a major overexpression of EPCR-binding domains in CM isolates. In contrast, ICAM-1-binding involvement appears less obvious with A-type ICAM-1-binding and dual receptor-binding domain expression in both CM and UM isolates. We did not find any variations in ICAM-1-binding motif sequences in CM compared to UM isolates. UM and CM patients infected with isolates expressing the ICAM-1-binding motif displayed similar IgG levels against DBLβ3 recombinant protein. Our study raises interrogations about the role of these domains in CM physiopathology and questions their use in vaccine strategies against cerebral malaria.
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35
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Andrade CM, Fleckenstein H, Thomson-Luque R, Doumbo S, Lima NF, Anderson C, Hibbert J, Hopp CS, Tran TM, Li S, Niangaly M, Cisse H, Doumtabe D, Skinner J, Sturdevant D, Ricklefs S, Virtaneva K, Asghar M, Homann MV, Turner L, Martins J, Allman EL, N'Dri ME, Winkler V, Llinás M, Lavazec C, Martens C, Färnert A, Kayentao K, Ongoiba A, Lavstsen T, Osório NS, Otto TD, Recker M, Traore B, Crompton PD, Portugal S. Increased circulation time of Plasmodium falciparum underlies persistent asymptomatic infection in the dry season. Nat Med 2020; 26:1929-1940. [PMID: 33106664 DOI: 10.1038/s41591-020-1084-0] [Citation(s) in RCA: 67] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 08/27/2020] [Indexed: 12/25/2022]
Abstract
The dry season is a major challenge for Plasmodium falciparum parasites in many malaria endemic regions, where water availability limits mosquito vectors to only part of the year. How P. falciparum bridges two transmission seasons months apart, without being cleared by the human host or compromising host survival, is poorly understood. Here we show that low levels of P. falciparum parasites persist in the blood of asymptomatic Malian individuals during the 5- to 6-month dry season, rarely causing symptoms and minimally affecting the host immune response. Parasites isolated during the dry season are transcriptionally distinct from those of individuals with febrile malaria in the transmission season, coinciding with longer circulation within each replicative cycle of parasitized erythrocytes without adhering to the vascular endothelium. Low parasite levels during the dry season are not due to impaired replication but rather to increased splenic clearance of longer-circulating infected erythrocytes, which likely maintain parasitemias below clinical and immunological radar. We propose that P. falciparum virulence in areas of seasonal malaria transmission is regulated so that the parasite decreases its endothelial binding capacity, allowing increased splenic clearance and enabling several months of subclinical parasite persistence.
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Affiliation(s)
- Carolina M Andrade
- Center for Infectious Diseases, Parasitology, Heidelberg University Hospital, Heidelberg, Germany
| | - Hannah Fleckenstein
- Center for Infectious Diseases, Parasitology, Heidelberg University Hospital, Heidelberg, Germany
| | - Richard Thomson-Luque
- Center for Infectious Diseases, Parasitology, Heidelberg University Hospital, Heidelberg, Germany
| | - Safiatou Doumbo
- Mali International Center of Excellence in Research, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Nathalia F Lima
- Center for Infectious Diseases, Parasitology, Heidelberg University Hospital, Heidelberg, Germany
| | - Carrie Anderson
- Center for Infectious Diseases, Parasitology, Heidelberg University Hospital, Heidelberg, Germany
| | - Julia Hibbert
- Center for Infectious Diseases, Parasitology, Heidelberg University Hospital, Heidelberg, Germany
| | - Christine S Hopp
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | - Tuan M Tran
- Division of Infectious Diseases, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Shanping Li
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | - Moussa Niangaly
- Mali International Center of Excellence in Research, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Hamidou Cisse
- Mali International Center of Excellence in Research, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Didier Doumtabe
- Mali International Center of Excellence in Research, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Jeff Skinner
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | - Dan Sturdevant
- Rocky Mountain Laboratory Research Technologies Section, Genomics Unit, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
| | - Stacy Ricklefs
- Rocky Mountain Laboratory Research Technologies Section, Genomics Unit, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
| | - Kimmo Virtaneva
- Rocky Mountain Laboratory Research Technologies Section, Genomics Unit, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
| | - Muhammad Asghar
- Department of Medicine Solna, Division of Infectious Diseases, Karolinska Institutet, Stockholm, Sweden.,Department of Infectious Diseases, Karolinska University Hospital, Stockholm, Sweden
| | - Manijeh Vafa Homann
- Department of Medicine Solna, Division of Infectious Diseases, Karolinska Institutet, Stockholm, Sweden.,Department of Infectious Diseases, Karolinska University Hospital, Stockholm, Sweden
| | - Louise Turner
- Department of Immunology and Microbiology, Centre for Medical Parasitology, Faculty of Health and Medical Sciences, University of Copenhagen, København N, Denmark.,Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), Copenhagen, Denmark
| | - Joana Martins
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Portugal and ICVS/3B's -PT Government Associate Laboratory, Braga, Portugal
| | - Erik L Allman
- Department of Biochemistry and Molecular Biology, Huck Center for Malaria Research, The Pennsylvania State University, State College, PA, USA
| | | | - Volker Winkler
- Institute of Global Health, Heidelberg University Hospital, Heidelberg, Germany
| | - Manuel Llinás
- Department of Biochemistry and Molecular Biology, Huck Center for Malaria Research, The Pennsylvania State University, State College, PA, USA.,Department of Chemistry, The Pennsylvania State University, State College, PA, USA
| | | | - Craig Martens
- Rocky Mountain Laboratory Research Technologies Section, Genomics Unit, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
| | - Anna Färnert
- Department of Medicine Solna, Division of Infectious Diseases, Karolinska Institutet, Stockholm, Sweden.,Department of Infectious Diseases, Karolinska University Hospital, Stockholm, Sweden
| | - Kassoum Kayentao
- Mali International Center of Excellence in Research, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Aissata Ongoiba
- Mali International Center of Excellence in Research, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Thomas Lavstsen
- Department of Immunology and Microbiology, Centre for Medical Parasitology, Faculty of Health and Medical Sciences, University of Copenhagen, København N, Denmark.,Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), Copenhagen, Denmark
| | - Nuno S Osório
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Portugal and ICVS/3B's -PT Government Associate Laboratory, Braga, Portugal
| | - Thomas D Otto
- Institute of Infection, Immunity & Inflammation, MVLS, University of Glasgow, Glasgow, UK
| | - Mario Recker
- Centre for Mathematics & the Environment, University of Exeter, Penryn Campus, Penryn, UK
| | - Boubacar Traore
- Mali International Center of Excellence in Research, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Peter D Crompton
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | - Silvia Portugal
- Center for Infectious Diseases, Parasitology, Heidelberg University Hospital, Heidelberg, Germany. .,German Center for Infection Research (DZIF), Heidelberg, Heidelberg, Germany. .,Max Planck Institute for Infection Biology, Berlin, Germany.
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36
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Gnidehou S, Yanow SK. VAR2CSA Antibodies in Non-Pregnant Populations. Trends Parasitol 2020; 37:65-76. [PMID: 33067131 DOI: 10.1016/j.pt.2020.09.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 09/16/2020] [Accepted: 09/18/2020] [Indexed: 11/18/2022]
Abstract
The Plasmodium falciparum protein VAR2CSA is a critical mediator of placental malaria, and VAR2CSA antibodies (IgGs) are important to protect pregnant women. Although infrequently detected outside pregnancy, VAR2CSA IgGs were reported in men and children from Colombia and Brazil and in select African populations. These findings raise questions about the specificity of VAR2CSA IgGs and the mechanisms by which they are acquired outside pregnancy. Here we review the data on VAR2CSA IgGs in men and children from different malaria-endemic regions. We discuss experimental factors that may affect interpretation of the serological data and consider the biological relevance of VAR2CSA IgGs in non-pregnant populations. We propose potential mechanisms for the acquisition of VARCSA IgGs outside of pregnancy. We identify knowledge gaps and research priorities.
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Affiliation(s)
- Sedami Gnidehou
- Campus Saint-Jean, University of Alberta, Edmonton, AB, Canada; Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, AB, Canada.
| | - Stephanie K Yanow
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, AB, Canada; School of Public Health, University of Alberta, Edmonton, AB, Canada
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Bryant JM, Baumgarten S, Dingli F, Loew D, Sinha A, Claës A, Preiser PR, Dedon PC, Scherf A. Exploring the virulence gene interactome with CRISPR/dCas9 in the human malaria parasite. Mol Syst Biol 2020; 16:e9569. [PMID: 32816370 PMCID: PMC7440042 DOI: 10.15252/msb.20209569] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 07/17/2020] [Accepted: 07/22/2020] [Indexed: 12/13/2022] Open
Abstract
Mutually exclusive expression of the var multigene family is key to immune evasion and pathogenesis in Plasmodium falciparum, but few factors have been shown to play a direct role. We adapted a CRISPR-based proteomics approach to identify novel factors associated with var genes in their natural chromatin context. Catalytically inactive Cas9 ("dCas9") was targeted to var gene regulatory elements, immunoprecipitated, and analyzed with mass spectrometry. Known and novel factors were enriched including structural proteins, DNA helicases, and chromatin remodelers. Functional characterization of PfISWI, an evolutionarily divergent putative chromatin remodeler enriched at the var gene promoter, revealed a role in transcriptional activation. Proteomics of PfISWI identified several proteins enriched at the var gene promoter such as acetyl-CoA synthetase, a putative MORC protein, and an ApiAP2 transcription factor. These findings validate the CRISPR/dCas9 proteomics method and define a new var gene-associated chromatin complex. This study establishes a tool for targeted chromatin purification of unaltered genomic loci and identifies novel chromatin-associated factors potentially involved in transcriptional control and/or chromatin organization of virulence genes in the human malaria parasite.
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Affiliation(s)
- Jessica M Bryant
- Biology of Host‐Parasite Interactions UnitInstitut PasteurParisFrance
- INSERM U1201ParisFrance
- CNRS ERL9195ParisFrance
| | - Sebastian Baumgarten
- Biology of Host‐Parasite Interactions UnitInstitut PasteurParisFrance
- INSERM U1201ParisFrance
- CNRS ERL9195ParisFrance
| | - Florent Dingli
- Institut CuriePSL Research UniversityCentre de RechercheMass Spectrometry and Proteomics FacilityParisFrance
| | - Damarys Loew
- Institut CuriePSL Research UniversityCentre de RechercheMass Spectrometry and Proteomics FacilityParisFrance
| | - Ameya Sinha
- School of Biological SciencesNanyang Technological UniversitySingaporeSingapore
- Antimicrobial Resistance Interdisciplinary Research GroupSingapore‐MIT Alliance for Research and TechnologySingaporeSingapore
| | - Aurélie Claës
- Biology of Host‐Parasite Interactions UnitInstitut PasteurParisFrance
- INSERM U1201ParisFrance
- CNRS ERL9195ParisFrance
| | - Peter R Preiser
- School of Biological SciencesNanyang Technological UniversitySingaporeSingapore
- Antimicrobial Resistance Interdisciplinary Research GroupSingapore‐MIT Alliance for Research and TechnologySingaporeSingapore
| | - Peter C Dedon
- Antimicrobial Resistance Interdisciplinary Research GroupSingapore‐MIT Alliance for Research and TechnologySingaporeSingapore
- Department of Biological EngineeringMassachusetts Institute of TechnologyCambridgeMAUSA
| | - Artur Scherf
- Biology of Host‐Parasite Interactions UnitInstitut PasteurParisFrance
- INSERM U1201ParisFrance
- CNRS ERL9195ParisFrance
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Obeng-Adjei N, Larremore DB, Turner L, Ongoiba A, Li S, Doumbo S, Yazew TB, Kayentao K, Miller LH, Traore B, Pierce SK, Buckee CO, Lavstsen T, Crompton PD, Tran TM. Longitudinal analysis of naturally acquired PfEMP1 CIDR domain variant antibodies identifies associations with malaria protection. JCI Insight 2020; 5:137262. [PMID: 32427581 DOI: 10.1172/jci.insight.137262] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Accepted: 05/06/2020] [Indexed: 01/03/2023] Open
Abstract
BACKGROUNDMalaria pathogenicity is determined, in part, by the adherence of Plasmodium falciparum-infected erythrocytes to the microvasculature mediated via specific interactions between P. falciparum erythrocyte membrane protein (PfEMP1) variant domains and host endothelial receptors. Naturally acquired antibodies against specific PfEMP1 variants can play an important role in clinical protection against malaria.METHODSWe evaluated IgG responses against a repertoire of PfEMP1 CIDR domain variants to determine the rate and order of variant-specific antibody acquisition and their association with protection against febrile malaria in a prospective cohort study conducted in an area of intense, seasonal malaria transmission.RESULTSUsing longitudinal data, we found that IgG antibodies against the pathogenic domain variants CIDRα1.7 and CIDRα1.8 were acquired the earliest. Furthermore, IgG antibodies against CIDRγ3 were associated with reduced prospective risk of febrile malaria and recurrent malaria episodes.CONCLUSIONThis study provides evidence that acquisition of IgG antibodies against PfEMP1 variants is ordered and demonstrates that antibodies against CIDRα1 domains are acquired the earliest in children residing in an area of intense, seasonal malaria transmission. Future studies will need to validate these findings in other transmission settings and determine the functional activity of these naturally acquired CIDR variant-specific antibodies.TRIAL REGISTRATIONClinicalTrials.gov NCT01322581.FUNDINGDivision of Intramural Research, National Institute of Allergy and Infectious Diseases, NIH.
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Affiliation(s)
- Nyamekye Obeng-Adjei
- Malaria Infection Biology and Immunity Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases (NIAID), NIH, Rockville, Maryland, USA.,Innate Immunity Research Unit, GlaxoSmithKline, Collegeville, Pennsylvania, USA
| | - Daniel B Larremore
- Department of Computer Science and.,BioFrontiers Institute, University of Colorado Boulder, Boulder, Colorado, USA
| | - Louise Turner
- Centre for Medical Parasitology, Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark. Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark
| | - Aissata Ongoiba
- Mali International Center of Excellence in Research, University of Sciences, Technique and Technology of Bamako, Bamako, Mali
| | - Shanping Li
- Malaria Infection Biology and Immunity Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases (NIAID), NIH, Rockville, Maryland, USA
| | - Safiatou Doumbo
- Mali International Center of Excellence in Research, University of Sciences, Technique and Technology of Bamako, Bamako, Mali
| | | | - Kassoum Kayentao
- Mali International Center of Excellence in Research, University of Sciences, Technique and Technology of Bamako, Bamako, Mali
| | - Louis H Miller
- Laboratory of Malaria and Vector Research, NIAID, NIH, Rockville, Maryland, USA
| | - Boubacar Traore
- Mali International Center of Excellence in Research, University of Sciences, Technique and Technology of Bamako, Bamako, Mali
| | | | - Caroline O Buckee
- Center for Communicable Disease Dynamics, Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, USA
| | - Thomas Lavstsen
- Centre for Medical Parasitology, Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark. Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark
| | - Peter D Crompton
- Malaria Infection Biology and Immunity Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases (NIAID), NIH, Rockville, Maryland, USA
| | - Tuan M Tran
- Malaria Infection Biology and Immunity Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases (NIAID), NIH, Rockville, Maryland, USA.,Division of Infectious Diseases, Department of Medicine, and.,Ryan White Center for Pediatric Infectious Disease and Global Health, Department of Pediatrics, Indiana University School of Medicine, Indianapolis, Indiana, USA
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Dimonte S, Bruske EI, Enderes C, Otto TD, Turner L, Kremsner P, Frank M. Identification of a conserved var gene in different Plasmodium falciparum strains. Malar J 2020; 19:194. [PMID: 32471507 PMCID: PMC7260770 DOI: 10.1186/s12936-020-03257-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Accepted: 05/15/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The multicopy var gene family of Plasmodium falciparum is of crucial importance for pathogenesis and antigenic variation. So far only var2csa, the var gene responsible for placental malaria, was found to be highly conserved among all P. falciparum strains. Here, a new conserved 3D7 var gene (PF3D7_0617400) is identified in several field isolates. METHODS DNA sequencing, transcriptional analysis, Cluster of Differentiation (CD) 36-receptor binding, indirect immunofluorescence with PF3D7_0617400-antibodies and quantification of surface reactivity against semi-immune sera were used to characterize an NF54 clone and a Gabonese field isolate clone (MOA C3) transcribing the gene. A population of 714 whole genome sequenced parasites was analysed to characterize the conservation of the locus in African and Asian isolates. The genetic diversity of two var2csa fragments was compared with the genetic diversity of 57 microsatellites fragments in field isolates. RESULTS PFGA01_060022400 was identified in a Gabonese parasite isolate (MOA) from a chronic infection and found to be 99% identical with PF3D7_0617400 of the 3D7 genome strain. Transcriptional analysis and immunofluorescence showed expression of the gene in an NF54 and a MOA clone but CD36 binding assays and surface reactivity to semi-immune sera differed markedly in the two clones. Long-read Pacific bioscience whole genome sequencing showed that PFGA01_060022400 is located in the internal cluster of chromosome 6. The full length PFGA01_060022400 was detected in 36 of 714 P. falciparum isolates and 500 bp fragments were identified in more than 100 isolates. var2csa was in parts highly conserved (He = 0) but in other parts as variable (He = 0.86) as the 57 microsatellites markers (He = 0.8). CONCLUSIONS Individual var gene sequences exhibit conservation in the global parasite population suggesting that purifying selection may limit overall genetic diversity of some var genes. Notably, field and laboratory isolates expressing the same var gene exhibit markedly different phenotypes.
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Affiliation(s)
- Sandra Dimonte
- Institute of Tropical Medicine, University of Tuebingen, Wilhelmstr. 27, 72074, Tuebingen, Germany
| | - Ellen I Bruske
- Institute of Tropical Medicine, University of Tuebingen, Wilhelmstr. 27, 72074, Tuebingen, Germany
| | - Corinna Enderes
- Institute of Tropical Medicine, University of Tuebingen, Wilhelmstr. 27, 72074, Tuebingen, Germany
| | - Thomas D Otto
- Malaria Programme, Wellcome Trust Sanger Institute, Hinxton, CB10 1SA, UK.,Centre of Immunobiology, Institute of Infection, Immunity & Inflammation, College of MVLS, University of Glasgow, Glasgow, UK
| | - Louise Turner
- Centre for Medical Parasitology, Department of Immunology and Microbiology (ISIM), Faculty of Health and Medical Sciences, University of Copenhagen, 1165, Copenhagen, Denmark.,Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), 2100, Copenhagen, Denmark
| | - Peter Kremsner
- Institute of Tropical Medicine, University of Tuebingen, Wilhelmstr. 27, 72074, Tuebingen, Germany
| | - Matthias Frank
- Institute of Tropical Medicine, University of Tuebingen, Wilhelmstr. 27, 72074, Tuebingen, Germany.
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Messenger RNAs with large numbers of upstream open reading frames are translated via leaky scanning and reinitiation in the asexual stages of Plasmodium falciparum. Parasitology 2020; 147:1100-1113. [DOI: 10.1017/s0031182020000840] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
AbstractThe genome of Plasmodium falciparum has one of the most skewed base-pair compositions of any eukaryote, with an AT content of 80–90%. As start and stop codons are AT-rich, the probability of finding upstream open reading frames (uORFs) in messenger RNAs (mRNAs) is high and parasite mRNAs have an average of 11 uORFs in their leader sequences. Similar to other eukaryotes, uORFs repress the translation of the downstream open reading frame (dORF) in P. falciparum, yet the parasite translation machinery is able to bypass these uORFs and reach the dORF to initiate translation. This can happen by leaky scanning and/or reinitiation.In this report, we assessed leaky scanning and reinitiation by studying the effect of uORFs on the translation of a dORF, in this case, the luciferase reporter gene, and showed that both mechanisms are employed in the asexual blood stages of P. falciparum. Furthermore, in addition to the codon usage of the uORF, translation of the dORF is governed by the Kozak sequence and length of the uORF, and inter-cistronic distance between the uORF and dORF. Based on these features whole-genome data was analysed to uncover classes of genes that might be regulated by uORFs. This study indicates that leaky scanning and reinitiation appear to be widespread in asexual stages of P. falciparum, which may require modifications of existing factors that are involved in translation initiation in addition to novel, parasite-specific proteins.
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41
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Fleckenstein H, Portugal S. Binding brain better-matching var genes and endothelial receptors. EMBO Mol Med 2020; 11:emmm.201810137. [PMID: 30804082 PMCID: PMC6404108 DOI: 10.15252/emmm.201810137] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Cerebral malaria remains a major cause of death for African children, and mechanistic insights regarding the establishment of brain pathology are greatly needed. Expression of specific domains of parasite's var genes promoting brain adhesion of infected erythrocytes had been previously identified, but binding specificities and the receptor preference in the brain endothelial cells had not been fully described. The study by Storm et al (2019) in this issue of EMBO Molecular Medicine demonstrates that binding to brain endothelial cells via EPCR and ICAM‐1 is increased in parasites causing cerebral malaria compared to parasites causing uncomplicated malaria. Furthermore, expression levels of var genes encoding the CIDRα1 domain with EPCR affinity correlate with the receptor‐dependent binding to brain, but not dermal endothelial cells, highlighting the important role of EPCR in cerebral malaria pathology.
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Affiliation(s)
- Hannah Fleckenstein
- Center for Infectious Diseases, Parasitology, Heidelberg University Hospital, Heidelberg, Germany
| | - Silvia Portugal
- Center for Infectious Diseases, Parasitology, Heidelberg University Hospital, Heidelberg, Germany
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Harmsen C, Turner L, Thrane S, Sander AF, Theander TG, Lavstsen T. Immunization with virus-like particles conjugated to CIDRα1 domain of Plasmodium falciparum erythrocyte membrane protein 1 induces inhibitory antibodies. Malar J 2020; 19:132. [PMID: 32228596 PMCID: PMC7106694 DOI: 10.1186/s12936-020-03201-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Accepted: 03/23/2020] [Indexed: 01/23/2023] Open
Abstract
BACKGROUND During the erythrocytic cycle, Plasmodium falciparum malaria parasites express P. falciparum Erythrocyte Membrane Protein 1 (PfEMP1) that anchor the infected erythrocytes (IE) to the vascular lining of the host. The CIDRα1 domain of PfEMP1 is responsible for binding host endothelial protein C receptor (EPCR), and increasing evidence support that this interaction triggers severe malaria, accounting for the majority of malaria-related deaths. In high transmission regions, children develop immunity to severe malaria after the first few infections. This immunity is believed to be mediated by antibodies targeting and inhibiting PfEMP1, causing infected erythrocytes to circulate and be cleared in the spleen. The development of immunity to malaria coincides with acquisition of broad antibody reactivity across the CIDRα1 protein family. Altogether, this identifies CIDRα1 as an important vaccine target. However, the antigenic diversity of the CIDRα1 domain family is a challenge for vaccine development. METHODS Immune responses in mice vaccinated with Virus-Like Particles (VLP) presenting CIDRα1 antigens were investigated. Antibody reactivity was tested to a panel of recombinant CIDRα1 domains, and the antibodies ability to inhibit EPCR binding by the recombinant CIDRα1 domains was tested in Luminex-based multiplex assays. RESULTS VLP-presented CIDRα1.4 antigens induced a rapid and strong IgG response capable of inhibiting EPCR-binding of multiple CIDRα1 domains mainly within the group A CIDRα1.4-7 subgroups. CONCLUSIONS The study observations mirror those from previous CIDRα1 vaccine studies using other vaccine constructs and platforms. This suggests that broad CIDRα1 antibody reactivity may be achieved through vaccination with a limited number of CIDRα1 variants. In addition, this study suggest that this may be achieved through vaccination with a human compatible VLP vaccine platform.
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Affiliation(s)
- Charlotte Harmsen
- Centre for Medical Parasitology, Department of Immunology and Microbiology (ISIM), Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), Copenhagen, Denmark
| | - Louise Turner
- Centre for Medical Parasitology, Department of Immunology and Microbiology (ISIM), Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), Copenhagen, Denmark
| | - Susan Thrane
- Centre for Medical Parasitology, Department of Immunology and Microbiology (ISIM), Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), Copenhagen, Denmark
| | - Adam F Sander
- Centre for Medical Parasitology, Department of Immunology and Microbiology (ISIM), Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), Copenhagen, Denmark
| | - Thor G Theander
- Centre for Medical Parasitology, Department of Immunology and Microbiology (ISIM), Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), Copenhagen, Denmark
| | - Thomas Lavstsen
- Centre for Medical Parasitology, Department of Immunology and Microbiology (ISIM), Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark. .,Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), Copenhagen, Denmark.
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Evolution of Host Specificity by Malaria Parasites through Altered Mechanisms Controlling Genome Maintenance. mBio 2020; 11:mBio.03272-19. [PMID: 32184256 PMCID: PMC7078485 DOI: 10.1128/mbio.03272-19] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Malaria remains one of the most prevalent and deadly infectious diseases of the developing world, causing approximately 228 million clinical cases and nearly half a million deaths annually. The disease is caused by protozoan parasites of the genus Plasmodium, and of the five species capable of infecting humans, infections with P. falciparum are the most severe. In addition to the parasites that infect people, there are hundreds of additional species that infect birds, reptiles, and other mammals, each exquisitely evolved to meet the specific challenges inherent to survival within their respective hosts. By comparing the unique strategies that each species has evolved, key insights into host-parasite interactions can be gained, including discoveries regarding the pathogenesis of human disease. Here, we describe the surprising observation that closely related parasites with different hosts have evolved remarkably different methods for repairing their genomes. This observation has important implications for the ability of parasites to maintain chronic infections and for the development of host immunity. The protozoan parasites that cause malaria infect a wide variety of vertebrate hosts, including birds, reptiles, and mammals, and the evolutionary pressures inherent to the host-parasite relationship have profoundly shaped the genomes of both host and parasite. Here, we report that these selective pressures have resulted in unexpected alterations to one of the most basic aspects of eukaryotic biology, the maintenance of genome integrity through DNA repair. Malaria parasites that infect humans continuously generate genetic diversity within their antigen-encoding gene families through frequent ectopic recombination between gene family members, a process that is a crucial feature of the persistence of malaria globally. The continuous generation of antigen diversity ensures that different parasite isolates are antigenically distinct, thus preventing extensive cross-reactive immunity and enabling parasites to maintain stable transmission within human populations. However, the molecular basis of the recombination between gene family members is not well understood. Through computational analyses of the antigen-encoding, multicopy gene families of different Plasmodium species, we report the unexpected observation that malaria parasites that infect rodents do not display the same degree of antigen diversity as observed in Plasmodium falciparum and appear to undergo significantly less ectopic recombination. Using comparative genomics, we also identify key molecular components of the diversification process, thus shedding new light on how malaria parasites balance the maintenance of genome integrity with the requirement for continuous genetic diversification.
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44
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Wang WF, Zhang YL. PfSWIB, a potential chromatin regulator for var gene regulation and parasite development in Plasmodium falciparum. Parasit Vectors 2020; 13:48. [PMID: 32019597 PMCID: PMC7001229 DOI: 10.1186/s13071-020-3918-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Accepted: 01/29/2020] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Various transcription factors are involved in the process of mutually exclusive expression and clonal variation of the Plasmodium multigene (var) family. Recent studies revealed that a P. falciparum SWI/SNF-related matrix-associated actin-dependent regulator of chromatin (PfSWIB) might trigger stage-specific programmed cell death (PCD), and was not only crucial for the survival and development of parasite, but also had profound effects on the parasite by interacting with other unknown proteins. However, it remains unclear whether PfSIWB is involved in transcriptional regulation of this virulence gene and its functional properties. METHODS A conditional knockdown system "PfSWIB-FKBP-LID" was introduced to the parasite clone 3D7, and an integrated parasite line "PfSWIB-HA-FKBP-LID" was obtained by drug cycling and clone screening. Growth curve analysis (GCA) was performed to investigate the growth and development of different parasite lines during 96 h in vitro culturing, by assessing parasitemia. Finally, we performed qPCR assays to detect var gene expression profiling in various comparison groups, as well as the mutually exclusive expression pattern of the var genes within a single 48 h life-cycle of P. falciparum in different parasite lines. In addition, RNA-seq was applied to analyze the var gene expression in different lines. RESULTS GCA revealed that conditional knockdown of PfSWIB could interfere with the growth and development of P. falciparum. The parasitemia of PfSWIB∆ showed a significant decline at 96 h during in vitro culture compared with the PfSWIB and 3D7 lines (P < 0.0001). qPCR and RNA-seq analysis confirmed that depletion of PfSWIB not only silences upsA, upsC and partial upsB var genes, as well as removes the silencing of partial upsB var genes at the ring stage in PfSWIB∆ line, but also leads to aberrant expression of upsA and partial upsB/upsC var genes at the mature stage of P. falciparum, during a single 48-h life-cycle. CONCLUSIONS We demonstrated that PfSWIB was involved in the process of clonal variation in var gene expression, and crucial for the survival and development of Plasmodium parasite. These findings could provide better understanding of the mechanism and function of PfSWIB contributing to the pathogenesis in malaria parasites.
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Affiliation(s)
- Wei-Feng Wang
- Central Laboratory, Shanghai Tenth People's Hospital, Tongji University, Shanghai, 200072, China.,Institute for Infectious Diseases and Vaccine Development, Tongji University School of Medicine, 1239 Siping Road, Shanghai, 200092, China
| | - Yi-Long Zhang
- Department of Tropical Diseases, Faculty of Naval Medicine, Second Military Medical University, Shanghai, 200433, China. .,Institute for Infectious Diseases and Vaccine Development, Tongji University School of Medicine, 1239 Siping Road, Shanghai, 200092, China.
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45
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Jensen AR, Adams Y, Hviid L. Cerebral Plasmodium falciparum malaria: The role of PfEMP1 in its pathogenesis and immunity, and PfEMP1-based vaccines to prevent it. Immunol Rev 2020; 293:230-252. [PMID: 31562653 PMCID: PMC6972667 DOI: 10.1111/imr.12807] [Citation(s) in RCA: 81] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 09/04/2019] [Accepted: 09/09/2019] [Indexed: 12/13/2022]
Abstract
Malaria, a mosquito-borne infectious disease caused by parasites of the genus Plasmodium continues to be a major health problem worldwide. The unicellular Plasmodium-parasites have the unique capacity to infect and replicate within host erythrocytes. By expressing variant surface antigens Plasmodium falciparum has evolved to avoid protective immune responses; as a result in endemic areas anti-malaria immunity develops gradually over many years of multiple and repeated infections. We are studying the role of Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) expressed by asexual stages of P. falciparum responsible for the pathogenicity of severe malaria. The immunopathology of falciparum malaria has been linked to cyto-adhesion of infected erythrocytes to specific host receptors. A greater appreciation of the PfEMP1 molecules important for the development of protective immunity and immunopathology is a prerequisite for the rational discovery and development of a safe and protective anti-disease malaria vaccine. Here we review the role of ICAM-1 and EPCR receptor adhering falciparum-parasites in the development of severe malaria; we discuss our current research to understand the factors involved in the pathogenesis of cerebral malaria and the feasibility of developing a vaccine targeted specifically to prevent this disease.
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Affiliation(s)
- Anja Ramstedt Jensen
- Centre for Medical Parasitology at Department of Immunology and MicrobiologyFaculty of Health and Medical SciencesUniversity of CopenhagenCopenhagenDenmark
| | - Yvonne Adams
- Centre for Medical Parasitology at Department of Immunology and MicrobiologyFaculty of Health and Medical SciencesUniversity of CopenhagenCopenhagenDenmark
| | - Lars Hviid
- Centre for Medical Parasitology at Department of Immunology and MicrobiologyFaculty of Health and Medical SciencesUniversity of CopenhagenCopenhagenDenmark
- Department of Infectious DiseasesRigshospitaletCopenhagenDenmark
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Rambhatla JS, Turner L, Manning L, Laman M, Davis TME, Beeson JG, Mueller I, Warrel J, Theander TG, Lavstsen T, Rogerson SJ. Acquisition of Antibodies Against Endothelial Protein C Receptor-Binding Domains of Plasmodium falciparum Erythrocyte Membrane Protein 1 in Children with Severe Malaria. J Infect Dis 2019; 219:808-818. [PMID: 30365003 DOI: 10.1093/infdis/jiy564] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2018] [Accepted: 09/18/2018] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) mediates parasite sequestration in postcapillary venules in P. falciparum malaria. PfEMP1 types can be classified based on their cysteine-rich interdomain region (CIDR) domains. Antibodies to different PfEMP1 types develop gradually after repeated infections as children age, and antibodies to specific CIDR types may confer protection. METHODS Levels of immunoglobulin G to 35 recombinant CIDR domains were measured by means of Luminex assay in acute-stage (baseline) and convalescent-stage plasma samples from Papua New Guinean children with severe or uncomplicated malaria and in healthy age-matched community controls. RESULTS At baseline, antibody levels were similar across the 3 groups. After infection, children with severe malaria had higher antibody levels than those with uncomplicated malaria against the endothelial protein C receptor (EPCR) binding CIDRα1 domains, and this difference was largely confined to older children. Antibodies to EPCR-binding domains increased from presentation to follow-up in severe malaria, but not in uncomplicated malaria. CONCLUSIONS The acquisition of antibodies against EPCR-binding CIDRα1 domains of PfEMP1 after a severe malaria episode suggest that EPCR-binding PfEMP1 may have a role in the pathogenesis of severe malaria in Papua New Guinea.
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Affiliation(s)
- Janavi S Rambhatla
- Department of Medicine, The Peter Doherty Institute for Infection and Immunity, Parkville
| | - Louise Turner
- Centre for Medical Parasitology, Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen and Department of Infectious Diseases, Copenhagen University Hospital, Denmark
| | - Laurens Manning
- School of Medicine and Pharmacology, University of Western Australia, Harry Perkins Research Institute, Fiona Stanley Hospital, Murdoch
| | - Moses Laman
- Papua New Guinea Institute of Medical Research, Madang
| | - Timothy M E Davis
- School of Medicine and Pharmacology, University of Western Australia, Harry Perkins Research Institute, Fiona Stanley Hospital, Murdoch
| | - James G Beeson
- Macfarlane Burnet Institute for Medical Research and Public Health, Melbourne, Australia
| | - Ivo Mueller
- Department of Medical Biology, University of Melbourne, Parkville.,Walter and Eliza Hall Institute of Medical Research, Parkville.,Parasite and Insect Vectors Department, Institut Pasteur, Paris, France
| | | | - Thor G Theander
- Centre for Medical Parasitology, Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen and Department of Infectious Diseases, Copenhagen University Hospital, Denmark
| | - Thomas Lavstsen
- Centre for Medical Parasitology, Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen and Department of Infectious Diseases, Copenhagen University Hospital, Denmark
| | - Stephen J Rogerson
- Department of Medicine, The Peter Doherty Institute for Infection and Immunity, Parkville
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Kivisi CA, Muthui M, Hunt M, Fegan G, Otto TD, Githinji G, Warimwe GM, Rance R, Marsh K, Bull PC, Abdi AI. Exploring Plasmodium falciparum Var Gene Expression to Assess Host Selection Pressure on Parasites During Infancy. Front Immunol 2019; 10:2328. [PMID: 31681266 PMCID: PMC6798654 DOI: 10.3389/fimmu.2019.02328] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 09/16/2019] [Indexed: 11/13/2022] Open
Abstract
In sub-Saharan Africa, children below 5 years bear the greatest burden of severe malaria because they lack naturally acquired immunity that develops following repeated exposure to infections by Plasmodium falciparum. Antibodies to the surface of P. falciparum infected erythrocytes (IE) play an important role in this immunity. In children under the age of 6 months, relative protection from severe malaria is observed and this is thought to be partly due to trans-placental acquired protective maternal antibodies. However, the protective effect of maternal antibodies has not been fully established, especially the role of antibodies to variant surface antigens (VSA) expressed on IE. Here, we assessed the immune pressure on parasites infecting infants using markers associated with the acquisition of naturally acquired immunity to surface antigens. We hypothesized that, if maternal antibodies to VSA imposed a selection pressure on parasites, then the expression of a relatively conserved subset of var genes called group A var genes in infants should change with waning maternal antibodies. To test this, we compared their expression in parasites from children between 0 and 12 months and above 12 months of age. The transcript quantity and the proportional expression of group A var subgroup, including those containing domain cassette 13, were positively associated with age during the first year of life, which contrasts with above 12 months. This was accompanied by a decline in infected erythrocyte surface antibodies and an increase in parasitemia during this period. The observed increase in group A var gene expression with age in the first year of life, when the maternal antibodies are waning and before acquisition of naturally acquired antibodies with repeated exposure, is consistent with the idea that maternally acquired antibodies impose a selection pressure on parasites that infect infants and may play a role in protecting these infants against severe malaria.
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Affiliation(s)
- Cheryl A Kivisi
- KEMRI Wellcome Trust Research Programme, Kilifi, Kenya.,Pwani University Biosciences Research Centre, Pwani University, Kilifi, Kenya.,Department of Biological Sciences, Pwani University, Kilifi, Kenya
| | | | - Martin Hunt
- Wellcome Sanger Institute, Cambridge, United Kingdom
| | - Greg Fegan
- KEMRI Wellcome Trust Research Programme, Kilifi, Kenya
| | | | | | - George M Warimwe
- KEMRI Wellcome Trust Research Programme, Kilifi, Kenya.,Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, United Kingdom
| | - Richard Rance
- Pwani University Biosciences Research Centre, Pwani University, Kilifi, Kenya
| | - Kevin Marsh
- KEMRI Wellcome Trust Research Programme, Kilifi, Kenya.,Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, United Kingdom
| | - Peter C Bull
- KEMRI Wellcome Trust Research Programme, Kilifi, Kenya
| | - Abdirahman I Abdi
- KEMRI Wellcome Trust Research Programme, Kilifi, Kenya.,Pwani University Biosciences Research Centre, Pwani University, Kilifi, Kenya
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Lennartz F, Smith C, Craig AG, Higgins MK. Structural insights into diverse modes of ICAM-1 binding by Plasmodium falciparum-infected erythrocytes. Proc Natl Acad Sci U S A 2019; 116:20124-20134. [PMID: 31527263 PMCID: PMC6778195 DOI: 10.1073/pnas.1911900116] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
A major determinant of pathogenicity in malaria caused by Plasmodium falciparum is the adhesion of parasite-infected erythrocytes to the vasculature or tissues of infected individuals. This occludes blood flow, leads to inflammation, and increases parasitemia by reducing spleen-mediated clearance of the parasite. This adhesion is mediated by PfEMP1, a multivariant family of around 60 proteins per parasite genome which interact with specific host receptors. One of the most common of these receptors is intracellular adhesion molecule-1 (ICAM-1), which is bound by 2 distinct groups of PfEMP1, A-type and B or C (BC)-type. Here, we present the structure of a domain from a B-type PfEMP1 bound to ICAM-1, revealing a complex binding site. Comparison with the existing structure of an A-type PfEMP1 bound to ICAM-1 shows that the 2 complexes share a globally similar architecture. However, while the A-type PfEMP1 bind ICAM-1 through a highly conserved binding surface, the BC-type PfEMP1 use a binding site that is more diverse in sequence, similar to how PfEMP1 interact with other human receptors. We also show that A- and BC-type PfEMP1 present ICAM-1 at different angles, perhaps influencing the ability of neighboring PfEMP1 domains to bind additional receptors. This illustrates the deep diversity of the PfEMP1 and demonstrates how variations in a single domain architecture can modulate binding to a specific ligand to control function and facilitate immune evasion.
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Affiliation(s)
- Frank Lennartz
- Department of Biochemistry, University of Oxford, OX1 3QU Oxford, United Kingdom
| | - Cameron Smith
- Department of Biochemistry, University of Oxford, OX1 3QU Oxford, United Kingdom
| | - Alister G Craig
- Liverpool School of Tropical Medicine, L3 5QA Liverpool, United Kingdom
| | - Matthew K Higgins
- Department of Biochemistry, University of Oxford, OX1 3QU Oxford, United Kingdom;
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Olsen RW, Ecklu-Mensah G, Bengtsson A, Ofori MF, Kusi KA, Koram KA, Hviid L, Adams Y, Jensen ATR. Acquisition of IgG to ICAM-1-Binding DBLβ Domains in the Plasmodium falciparum Erythrocyte Membrane Protein 1 Antigen Family Varies between Groups A, B, and C. Infect Immun 2019; 87:e00224-19. [PMID: 31308082 PMCID: PMC6759304 DOI: 10.1128/iai.00224-19] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Accepted: 07/03/2019] [Indexed: 12/31/2022] Open
Abstract
Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) is an important malaria virulence factor. The protein family can be divided into clinically relevant subfamilies. ICAM-1-binding group A PfEMP1 proteins also bind endothelial protein C receptor and have been associated with cerebral malaria in children. IgG to these PfEMP1 proteins is acquired later in life than that to group A PfEMP1 not binding ICAM-1. The kinetics of acquisition of IgG to group B and C PfEMP1 proteins binding ICAM-1 is unclear and was studied here. Gene sequences encoding group B and C PfEMP1 with DBLβ domains known to bind ICAM-1 were used to identify additional binders. Levels of IgG specific for DBLβ domains from group A, B, and C PfEMP1 binding or not binding ICAM-1 were measured in plasma from Ghanaian children with or without malaria. Seven new ICAM-1-binding DBLβ domains from group B and C PfEMP1 were identified. Healthy children had higher levels of IgG specific for ICAM-1-binding DBLβ domains from group A than from groups B and C. However, the opposite pattern was found in children with malaria, particularly among young patients. Acquisition of IgG specific for DBLβ domains binding ICAM-1 differs between PfEMP1 groups.
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MESH Headings
- Antibodies, Protozoan/biosynthesis
- Child
- Child, Preschool
- Erythrocytes/immunology
- Erythrocytes/parasitology
- Female
- Gene Expression
- Ghana
- Humans
- Immunoglobulin G/biosynthesis
- Infant
- Intercellular Adhesion Molecule-1/genetics
- Intercellular Adhesion Molecule-1/immunology
- Malaria, Cerebral/genetics
- Malaria, Cerebral/immunology
- Malaria, Cerebral/parasitology
- Malaria, Cerebral/pathology
- Malaria, Falciparum/genetics
- Malaria, Falciparum/immunology
- Malaria, Falciparum/parasitology
- Malaria, Falciparum/pathology
- Male
- Plasmodium falciparum/immunology
- Plasmodium falciparum/pathogenicity
- Polymorphism, Genetic
- Protein Binding
- Protein Domains
- Protozoan Proteins/classification
- Protozoan Proteins/genetics
- Protozoan Proteins/immunology
- Seasons
- Severity of Illness Index
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Affiliation(s)
- Rebecca W Olsen
- Centre for Medical Parasitology at Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Gertrude Ecklu-Mensah
- Department of Immunology, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
| | - Anja Bengtsson
- Centre for Medical Parasitology at Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Michael F Ofori
- Department of Immunology, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
| | - Kwadwo A Kusi
- Department of Immunology, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
| | - Kwadwo A Koram
- Department of Epidemiology, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
| | - Lars Hviid
- Centre for Medical Parasitology at Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), Copenhagen, Denmark
| | - Yvonne Adams
- Centre for Medical Parasitology at Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Anja T R Jensen
- Centre for Medical Parasitology at Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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50
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Bachmann A, Bruske E, Krumkamp R, Turner L, Wichers JS, Petter M, Held J, Duffy MF, Sim BKL, Hoffman SL, Kremsner PG, Lell B, Lavstsen T, Frank M, Mordmüller B, Tannich E. Controlled human malaria infection with Plasmodium falciparum demonstrates impact of naturally acquired immunity on virulence gene expression. PLoS Pathog 2019; 15:e1007906. [PMID: 31295334 PMCID: PMC6650087 DOI: 10.1371/journal.ppat.1007906] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Revised: 07/23/2019] [Accepted: 06/10/2019] [Indexed: 12/14/2022] Open
Abstract
The pathogenesis of Plasmodium falciparum malaria is linked to the variant surface antigen PfEMP1, which mediates tethering of infected erythrocytes to the host endothelium and is encoded by approximately 60 var genes per parasite genome. Repeated episodes of malaria infection result in the gradual acquisition of protective antibodies against PfEMP1 variants. The antibody repertoire is believed to provide a selective pressure driving the clonal expansion of parasites expressing unrecognized PfEMP1 variants, however, due to the lack of experimental in vivo models there is only limited experimental evidence in support of this concept. To get insight into the impact of naturally acquired immunity on the expressed var gene repertoire early during infection we performed controlled human malaria infections of 20 adult African volunteers with life-long malaria exposure using aseptic, purified, cryopreserved P. falciparum sporozoites (Sanaria PfSPZ Challenge) and correlated serological data with var gene expression patterns from ex vivo parasites. Among the 10 African volunteers who developed patent infections, individuals with low antibody levels showed a steep rise in parasitemia accompanied by broad activation of multiple, predominantly subtelomeric var genes, similar to what we previously observed in naïve volunteers. In contrast, individuals with intermediate antibody levels developed asymptomatic infections and the ex vivo parasite populations expressed only few var gene variants, indicative of clonal selection. Importantly, in contrast to parasites from naïve volunteers, expression of var genes coding for endothelial protein C receptor (EPCR)-binding PfEMP1 that are associated with severe childhood malaria was rarely detected in semi-immune adult African volunteers. Moreover, we followed var gene expression for up to six parasite replication cycles and demonstrated for the first time in vivo a shift in the dominant var gene variant. In conclusion, our data suggest that P. falciparum activates multiple subtelomeric var genes at the onset of blood stage infection facilitating rapid expansion of parasite clones which express PfEMP1 variants unrecognized by the host's immune system, thus promoting overall parasite survival in the face of host immunity.
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Affiliation(s)
- Anna Bachmann
- Department of Molecular Parasitology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
- German Center for Infection Research (DZIF), partner site Hamburg-Borstel-Lübeck-Riems, Germany
| | - Ellen Bruske
- Institute of Tropical Medicine, University Hospital Tübingen, Tübingen, Germany
| | - Ralf Krumkamp
- German Center for Infection Research (DZIF), partner site Hamburg-Borstel-Lübeck-Riems, Germany
- Infectious Disease Epidemiology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Louise Turner
- Centre for Medical Parasitology, University of Copenhagen, Copenhagen K, Denmark
| | - J. Stephan Wichers
- Department of Molecular Parasitology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Michaela Petter
- Mikrobiologisches Institut–Klinische Mikrobiologie, Immunologie und Hygiene, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, Erlangen, Germany
- School of BioSciences, Bio21 Institute, University of Melbourne, Parkville, Victoria, Australia
| | - Jana Held
- Institute of Tropical Medicine, University Hospital Tübingen, Tübingen, Germany
| | - Michael F. Duffy
- School of BioSciences, Bio21 Institute, University of Melbourne, Parkville, Victoria, Australia
| | | | | | - Peter G. Kremsner
- Institute of Tropical Medicine, University Hospital Tübingen, Tübingen, Germany
- German Center for Infection Research (DZIF), partner site Tübingen, Germany
| | - Bertrand Lell
- Institute of Tropical Medicine, University Hospital Tübingen, Tübingen, Germany
- Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon
- German Center for Infection Research (DZIF), African partner institution, CERMEL, Gabon
| | - Thomas Lavstsen
- Centre for Medical Parasitology, University of Copenhagen, Copenhagen K, Denmark
| | - Matthias Frank
- Institute of Tropical Medicine, University Hospital Tübingen, Tübingen, Germany
| | - Benjamin Mordmüller
- Institute of Tropical Medicine, University Hospital Tübingen, Tübingen, Germany
- German Center for Infection Research (DZIF), partner site Tübingen, Germany
| | - Egbert Tannich
- Department of Molecular Parasitology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
- German Center for Infection Research (DZIF), partner site Hamburg-Borstel-Lübeck-Riems, Germany
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