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Dunican C, Andradi-Brown C, Ebmeier S, Georgiadou A, Cunnington AJ. The malarial blood transcriptome: translational applications. Biochem Soc Trans 2024; 52:651-660. [PMID: 38421063 PMCID: PMC11088907 DOI: 10.1042/bst20230497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 02/20/2024] [Accepted: 02/21/2024] [Indexed: 03/02/2024]
Abstract
The blood transcriptome of malaria patients has been used extensively to elucidate the pathophysiological mechanisms and host immune responses to disease, identify candidate diagnostic and prognostic biomarkers, and reveal new therapeutic targets for drug discovery. This review gives a high-level overview of the three main translational applications of these studies (diagnostics, prognostics, and therapeutics) by summarising recent literature and outlining the main limitations and future directions of each application. It highlights the need for consistent and accurate definitions of disease states and subject groups and discusses how prognostic studies must distinguish clearly between analyses that attempt to predict future disease states and those which attempt to discriminate between current disease states (classification). Lastly it examines how many promising therapeutics fail due to the choice of imperfect animal models for pre-clinical testing and lack of appropriate validation studies in humans, and how future transcriptional studies may be utilised to overcome some of these limitations.
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Affiliation(s)
- Claire Dunican
- Section of Paediatric Infectious Disease, Department of Infectious Disease, Imperial College London, London, U.K
- Centre for Paediatrics and Child Health, Imperial College London, London, U.K
| | - Clare Andradi-Brown
- Section of Paediatric Infectious Disease, Department of Infectious Disease, Imperial College London, London, U.K
- Centre for Paediatrics and Child Health, Imperial College London, London, U.K
| | - Stefan Ebmeier
- Section of Paediatric Infectious Disease, Department of Infectious Disease, Imperial College London, London, U.K
- Centre for Paediatrics and Child Health, Imperial College London, London, U.K
| | - Athina Georgiadou
- Section of Paediatric Infectious Disease, Department of Infectious Disease, Imperial College London, London, U.K
- Centre for Paediatrics and Child Health, Imperial College London, London, U.K
| | - Aubrey J. Cunnington
- Section of Paediatric Infectious Disease, Department of Infectious Disease, Imperial College London, London, U.K
- Centre for Paediatrics and Child Health, Imperial College London, London, U.K
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2
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Amwoma JG, Kituyi S, Wakoli DM, Ochora DO, Chemwor G, Maisiba R, Okore W, Opot B, Juma D, Muok EM, Garges EC, Egbo TE, Nyabuga FN, Andagalu B, Akala HM. Comparative analysis of peripheral whole blood transcriptome from asymptomatic carriers reveals upregulation of subsets of surface proteins implicated in Plasmodium falciparum phenotypic plasticity. Biochem Biophys Rep 2024; 37:101596. [PMID: 38146350 PMCID: PMC10749222 DOI: 10.1016/j.bbrep.2023.101596] [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: 07/13/2023] [Revised: 11/17/2023] [Accepted: 11/27/2023] [Indexed: 12/27/2023] Open
Abstract
The molecular mechanism underlying Plasmodium falciparum's persistence in the asymptomatic phase of infection remains largely unknown. However, large-scale shifts in the parasites' gene expression during asymptomatic infections may enhance phenotypic plasticity, maximizing their fitness and leading to the persistence of the asymptomatic infections. To uncover these mechanisms, we aimed to identify parasite genetic factors implicated in asymptomatic infections through whole transcriptome analysis. We analyzed publicly available transcriptome datasets containing asymptomatic malaria (ASM), uncomplicated malaria (SM), and malaria-naïve (NSM) samples from 35 subjects for differentially expressed genes (DEGs) and long noncoding RNAs. Our analysis identified 755 and 1773 DEGs in ASM vs SM and NSM, respectively. These DEGs revealed sets of genes coding for proteins of unknown functions (PUFs) upregulated in ASM vs SM and ASM, suggesting their role in underlying fundamental molecular mechanisms during asymptomatic infections. Upregulated genes in ASM vs SM revealed a subset of 24 clonal variant genes (CVGs) involved in host-parasite and symbiotic interactions and modulation of the symbiont of host erythrocyte aggregation pathways. Moreover, we identified 237 differentially expressed noncoding RNAs in ASM vs SM, of which 11 were found to interact with CVGs, suggesting their possible role in regulating the expression of CVGs. Our results suggest that P. falciparum utilizes phenotypic plasticity as an adaptive mechanism during asymptomatic infections by upregulating clonal variant genes, with long noncoding RNAs possibly playing a crucial role in their regulation. Thus, our study provides insights into the parasites' genetic factors that confer a fitness advantage during asymptomatic infections.
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Affiliation(s)
- Joseph G. Amwoma
- Department of Biological Sciences, University of Embu, Kenya
- United States Army Medical Research Directorate-Africa (USAMRD-A), Kenya Medical Research Institute (KEMRI), Kisumu, Kenya
| | - Sarah Kituyi
- Department of Biological Sciences, University of Embu, Kenya
- Forgarty International Center of the National Institutes of Health, Bethesda, MD, USA
| | - Dancan M. Wakoli
- Department of Biochemistry and Molecular Biology, Egerton University, Kenya
| | - Douglas O. Ochora
- Department of Biological Sciences, School of Pure and Applied Sciences, Kisii University, Kenya
- DSI/NWU, Preclinical Drug Development Platform, Faculty of Health Sciences, North-West University, Potchefstroom, South Africa
| | - Gladys Chemwor
- United States Army Medical Research Directorate-Africa (USAMRD-A), Kenya Medical Research Institute (KEMRI), Kisumu, Kenya
| | - Risper Maisiba
- United States Army Medical Research Directorate-Africa (USAMRD-A), Kenya Medical Research Institute (KEMRI), Kisumu, Kenya
| | - Winnie Okore
- Department of Biomedical Sciences and Technology, Maseno University, Kenya
| | - Benjamin Opot
- United States Army Medical Research Directorate-Africa (USAMRD-A), Kenya Medical Research Institute (KEMRI), Kisumu, Kenya
| | - Dennis Juma
- United States Army Medical Research Directorate-Africa (USAMRD-A), Kenya Medical Research Institute (KEMRI), Kisumu, Kenya
| | - Eric M.O. Muok
- Center for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Eric C. Garges
- United States Army Medical Research Directorate-Africa (USAMRD-A), Kenya
| | - Timothy E. Egbo
- United States Army Medical Research Directorate-Africa (USAMRD-A), Kenya
| | | | - Ben Andagalu
- United States Army Medical Research Directorate-Africa (USAMRD-A), Kenya Medical Research Institute (KEMRI), Kisumu, Kenya
| | - Hoseah M. Akala
- United States Army Medical Research Directorate-Africa (USAMRD-A), Kenya Medical Research Institute (KEMRI), Kisumu, Kenya
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3
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Kimenyi KM, Akinyi MY, Mwikali K, Gilmore T, Mwangi S, Omer E, Gichuki B, Wambua J, Njunge J, Obiero G, Bejon P, Langhorne J, Abdi A, Ochola-Oyier LI. Distinct transcriptomic signatures define febrile malaria depending on initial infective states, asymptomatic or uninfected. BMC Infect Dis 2024; 24:140. [PMID: 38287287 PMCID: PMC10823747 DOI: 10.1186/s12879-024-08973-2] [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: 09/21/2023] [Accepted: 01/01/2024] [Indexed: 01/31/2024] Open
Abstract
BACKGROUND Cumulative malaria parasite exposure in endemic regions often results in the acquisition of partial immunity and asymptomatic infections. There is limited information on how host-parasite interactions mediate the maintenance of chronic symptomless infections that sustain malaria transmission. METHODS Here, we determined the gene expression profiles of the parasite population and the corresponding host peripheral blood mononuclear cells (PBMCs) from 21 children (< 15 years). We compared children who were defined as uninfected, asymptomatic and those with febrile malaria. RESULTS Children with asymptomatic infections had a parasite transcriptional profile characterized by a bias toward trophozoite stage (~ 12 h-post invasion) parasites and low parasite levels, while early ring stage parasites were characteristic of febrile malaria. The host response of asymptomatic children was characterized by downregulated transcription of genes associated with inflammatory responses, compared with children with febrile malaria,. Interestingly, the host responses during febrile infections that followed an asymptomatic infection featured stronger inflammatory responses, whereas the febrile host responses from previously uninfected children featured increased humoral immune responses. CONCLUSIONS The priming effect of prior asymptomatic infection may explain the blunted acquisition of antibody responses seen to malaria antigens following natural exposure or vaccination in malaria endemic areas.
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Affiliation(s)
- Kelvin M Kimenyi
- KEMRI‑Wellcome Trust Research Programme, Kilifi, Kenya
- Department of Biochemistry, University of Nairobi, Nairobi, Kenya
| | | | - Kioko Mwikali
- KEMRI‑Wellcome Trust Research Programme, Kilifi, Kenya
| | | | - Shaban Mwangi
- KEMRI‑Wellcome Trust Research Programme, Kilifi, Kenya
| | - Elisha Omer
- KEMRI‑Wellcome Trust Research Programme, Kilifi, Kenya
| | | | | | - James Njunge
- KEMRI‑Wellcome Trust Research Programme, Kilifi, Kenya
| | - George Obiero
- Department of Biochemistry, University of Nairobi, Nairobi, Kenya
| | - Philip Bejon
- KEMRI‑Wellcome Trust Research Programme, Kilifi, Kenya
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
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4
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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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5
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Muppidi P, Wright E, Wassmer SC, Gupta H. Diagnosis of cerebral malaria: Tools to reduce Plasmodium falciparum associated mortality. Front Cell Infect Microbiol 2023; 13:1090013. [PMID: 36844403 PMCID: PMC9947298 DOI: 10.3389/fcimb.2023.1090013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Accepted: 01/24/2023] [Indexed: 02/11/2023] Open
Abstract
Cerebral malaria (CM) is a major cause of mortality in Plasmodium falciparum (Pf) infection and is associated with the sequestration of parasitised erythrocytes in the microvasculature of the host's vital organs. Prompt diagnosis and treatment are key to a positive outcome in CM. However, current diagnostic tools remain inadequate to assess the degree of brain dysfunction associated with CM before the window for effective treatment closes. Several host and parasite factor-based biomarkers have been suggested as rapid diagnostic tools with potential for early CM diagnosis, however, no specific biomarker signature has been validated. Here, we provide an updated review on promising CM biomarker candidates and evaluate their applicability as point-of-care tools in malaria-endemic areas.
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Affiliation(s)
- Pranavi Muppidi
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Emily Wright
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Samuel C. Wassmer
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Himanshu Gupta
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Department of Biotechnology, Institute of Applied Sciences & Humanities, GLA University, Mathura, UP, India
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6
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An update on cerebral malaria for therapeutic intervention. Mol Biol Rep 2022; 49:10579-10591. [PMID: 35670928 DOI: 10.1007/s11033-022-07625-5] [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: 12/01/2021] [Accepted: 05/20/2022] [Indexed: 10/18/2022]
Abstract
BACKGROUND Cerebral malaria is often pronounced as a major life-threatening neurological complication of Plasmodium falciparum infection. The complex pathogenic landscape of the parasite and the associated neurological complications are still not elucidated properly. The growing concerns of drugresistant parasite strains along with the failure of anti-malarial drugs to subdue post-recovery neuro-cognitive dysfunctions in cerebral malaria patients have called for a demand to explore novel biomarkers and therapeutic avenues. Due course of the brain infection journey of the parasite, events such as sequestration of infected RBCs, cytoadherence, inflammation, endothelial activation, and blood-brain barrier disruption are considered critical. METHODS In this review, we briefly summarize the diverse pathogenesis of the brain-invading parasite associated with loss of the blood-brain barrier integrity. In addition, we also discuss proteomics, transcriptomics, and bioinformatics strategies to identify an array of new biomarkers and drug candidates. CONCLUSION A proper understanding of the parasite biology and mechanism of barrier disruption coupled with emerging state-of-art therapeutic approaches could be helpful to tackle cerebral malaria.
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7
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Plasmodium falciparum transcription in different clinical presentations of malaria associates with circulation time of infected erythrocytes. Nat Commun 2021; 12:4711. [PMID: 34330920 PMCID: PMC8324851 DOI: 10.1038/s41467-021-25062-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Accepted: 07/06/2021] [Indexed: 02/07/2023] Open
Abstract
Following Plasmodium falciparum infection, individuals can remain asymptomatic, present with mild fever in uncomplicated malaria cases, or show one or more severe malaria symptoms. Several studies have investigated associations between parasite transcription and clinical severity, but no broad conclusions have yet been drawn. Here, we apply a series of bioinformatic approaches based on P. falciparum's tightly regulated transcriptional pattern during its ~48-hour intraerythrocytic developmental cycle (IDC) to publicly available transcriptomes of parasites obtained from malaria cases of differing clinical severity across multiple studies. Our analysis shows that within each IDC, the circulation time of infected erythrocytes without sequestering to endothelial cells decreases with increasing parasitaemia or disease severity. Accordingly, we find that the size of circulating infected erythrocytes is inversely related to parasite density and disease severity. We propose that enhanced adhesiveness of infected erythrocytes leads to a rapid increase in parasite burden, promoting higher parasitaemia and increased disease severity.
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8
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Badaut C, Visitdesotrakul P, Chabry A, Bigey P, Tornyigah B, Roman J, Maroufou JA, Amoussou A, Ayivi BS, Sagbo G, Ndam NT, Oleinikov AV, Tahar R. IgG acquisition against PfEMP1 PF11_0521 domain cassette DC13, DBLβ3_D4 domain, and peptides located within these constructs in children with cerebral malaria. Sci Rep 2021; 11:3680. [PMID: 33574457 PMCID: PMC7878510 DOI: 10.1038/s41598-021-82444-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 12/30/2020] [Indexed: 11/09/2022] Open
Abstract
The Plasmodium falciparum erythrocyte-membrane-protein-1 (PF3D7_1150400/PF11_0521) contains both domain cassette DC13 and DBLβ3 domain binding to EPCR and ICAM-1 receptors, respectively. This type of PfEMP1 proteins with dual binding specificity mediate specific interactions with brain micro-vessels endothelium leading to the development of cerebral malaria (CM). Using plasma collected from children at time of hospital admission and after 30 days, we study an acquisition of IgG response to PF3D7_1150400/PF11_0521 DC13 and DBLβ3_D4 recombinant constructs, and five peptides located within these constructs, specifically in DBLα1.7_D2 and DBLβ3_D4 domains. We found significant IgG responses against the entire DC13, PF11_0521_DBLβ3_D4 domain, and peptides. The responses varied against different peptides and depended on the clinical status of children. The response was stronger at day 30, and mostly did not differ between CM and uncomplicated malaria (UM) groups. Specifically, the DBLβ3 B3-34 peptide that contains essential residues involved in the interaction between PF11_0521 DBLβ3_D4 domain and ICAM-1 receptor demonstrated significant increase in reactivity to IgG1 and IgG3 antibodies at convalescence. Further, IgG reactivity in CM group at time of admission against functionally active (ICAM-1-binding) PF11_0521 DBLβ3_D4 domain was associated with protection against severe anemia. These results support development of vaccine based on the PF3D7_1150400/PF11_0521 structures to prevent CM.
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Affiliation(s)
- Cyril Badaut
- Institut de Recherche Biomédicale des Armées, National Reference Laboratory for Arboviruses, Marseille, France
| | | | | | - Pascal Bigey
- Université de Paris, UMR 8151 CNRS - INSERM U1022 - ENSCP, 75006, Paris, France
| | | | | | - Jules Alao Maroufou
- Département de Pédiatrie, Hôpital Mère-Enfant La Lagune (CHUMEL) Cotonou, Cotonou, Benin
| | - Annick Amoussou
- Service de Pédiatrie, Centre Hospitalo-Universitaire, Suruléré (CHU-Suruléré, Cotonou, Benin
| | - Blaise Serge Ayivi
- Service de Pédiatrie, Centre National Hospitalo-Universitaire (CNHU), Cotonou, Benin
| | - Gratien Sagbo
- Service de Pédiatrie, Centre National Hospitalo-Universitaire (CNHU), Cotonou, Benin
| | | | - Andrew V Oleinikov
- Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, 33428, USA
| | - Rachida Tahar
- Université de Paris, MERIT, IRD, 75006, Paris, France. .,Institut de Recherche Pour le Développement (IRD), UMR 261 Mère et Enfant Face Aux Infections Tropicales, Université Paris-Descartes, 4, Avenue de l'observatoire, 75270, Paris, France.
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9
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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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10
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Chappell L, Ross P, Orchard L, Russell TJ, Otto TD, Berriman M, Rayner JC, Llinás M. Refining the transcriptome of the human malaria parasite Plasmodium falciparum using amplification-free RNA-seq. BMC Genomics 2020; 21:395. [PMID: 32513207 PMCID: PMC7278070 DOI: 10.1186/s12864-020-06787-5] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Accepted: 05/19/2020] [Indexed: 12/24/2022] Open
Abstract
Background Plasmodium parasites undergo several major developmental transitions during their complex lifecycle, which are enabled by precisely ordered gene expression programs. Transcriptomes from the 48-h blood stages of the major human malaria parasite Plasmodium falciparum have been described using cDNA microarrays and RNA-seq, but these assays have not always performed well within non-coding regions, where the AT-content is often 90–95%. Results We developed a directional, amplification-free RNA-seq protocol (DAFT-seq) to reduce bias against AT-rich cDNA, which we have applied to three strains of P. falciparum (3D7, HB3 and IT). While strain-specific differences were detected, overall there is strong conservation between the transcriptional profiles. For the 3D7 reference strain, transcription was detected from 89% of the genome, with over 78% of the genome transcribed into mRNAs. We also find that transcription from bidirectional promoters frequently results in non-coding, antisense transcripts. These datasets allowed us to refine the 5′ and 3′ untranslated regions (UTRs), which can be variable, long (> 1000 nt), and often overlap those of adjacent transcripts. Conclusions The approaches applied in this study allow a refined description of the transcriptional landscape of P. falciparum and demonstrate that very little of the densely packed P. falciparum genome is inactive or redundant. By capturing the 5′ and 3′ ends of mRNAs, we reveal both constant and dynamic use of transcriptional start sites across the intraerythrocytic developmental cycle that will be useful in guiding the definition of regulatory regions for use in future experimental gene expression studies.
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Affiliation(s)
- Lia Chappell
- Wellcome Sanger Institute, Wellcome Genome Campus, Cambridge, CB10 1SA, UK
| | - Philipp Ross
- Department of Biochemistry & Molecular Biology and Huck Center for Malaria Research, Pennsylvania State University, University Park, PA, 16802, USA.,Present Address: Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, 60637, USA
| | - Lindsey Orchard
- Department of Biochemistry & Molecular Biology and Huck Center for Malaria Research, Pennsylvania State University, University Park, PA, 16802, USA
| | - Timothy J Russell
- Department of Biochemistry & Molecular Biology and Huck Center for Malaria Research, Pennsylvania State University, University Park, PA, 16802, USA
| | - Thomas D Otto
- Wellcome Sanger Institute, Wellcome Genome Campus, Cambridge, CB10 1SA, UK.,Present Address: Institute of Infection, Immunity and Inflammation, MVLS, University of Glasgow, Glasgow, G12 8TA, UK
| | - Matthew Berriman
- Wellcome Sanger Institute, Wellcome Genome Campus, Cambridge, CB10 1SA, UK
| | - Julian C Rayner
- Wellcome Sanger Institute, Wellcome Genome Campus, Cambridge, CB10 1SA, UK.,Present Address: Cambridge Institute for Medical Research, University of Cambridge, Cambridge, CB2 0XY, UK
| | - Manuel Llinás
- Department of Biochemistry & Molecular Biology and Huck Center for Malaria Research, Pennsylvania State University, University Park, PA, 16802, USA. .,Department of Chemistry, Pennsylvania State University, University Park, PA, 16802, USA.
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11
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Llorà-Batlle O, Tintó-Font E, Cortés A. Transcriptional variation in malaria parasites: why and how. Brief Funct Genomics 2020; 18:329-341. [PMID: 31114839 DOI: 10.1093/bfgp/elz009] [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: 10/23/2018] [Revised: 02/04/2019] [Accepted: 04/10/2019] [Indexed: 12/24/2022] Open
Abstract
Transcriptional differences enable the generation of alternative phenotypes from the same genome. In malaria parasites, transcriptional plasticity plays a major role in the process of adaptation to fluctuations in the environment. Multiple studies with culture-adapted parasites and field isolates are starting to unravel the different transcriptional alternatives available to Plasmodium falciparum and the underlying molecular mechanisms. Here we discuss how epigenetic variation, directed transcriptional responses and also genetic changes that affect transcript levels can all contribute to transcriptional variation and, ultimately, parasite survival. Some transcriptional changes are driven by stochastic events. These changes can occur spontaneously, resulting in heterogeneity within parasite populations that provides the grounds for adaptation by dynamic natural selection. However, transcriptional changes can also occur in response to external cues. A better understanding of the mechanisms that the parasite has evolved to alter its transcriptome may ultimately contribute to the design of strategies to combat malaria to which the parasite cannot adapt.
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Affiliation(s)
- Oriol Llorà-Batlle
- ISGlobal, Hospital Clínic - Universitat de Barcelona, 08036 Barcelona, Catalonia, Spain
| | - Elisabet Tintó-Font
- ISGlobal, Hospital Clínic - Universitat de Barcelona, 08036 Barcelona, Catalonia, Spain
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12
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Thiam A, Sanka M, Ndiaye Diallo R, Torres M, Mbengue B, Nunez NF, Thiam F, Diop G, Victorero G, Nguyen C, Dieye A, Rihet P. Gene expression profiling in blood from cerebral malaria patients and mild malaria patients living in Senegal. BMC Med Genomics 2019; 12:148. [PMID: 31666081 PMCID: PMC6821028 DOI: 10.1186/s12920-019-0599-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Accepted: 10/09/2019] [Indexed: 01/06/2023] Open
Abstract
Background Plasmodium falciparum malaria remains a major health problem in Africa. The mechanisms of pathogenesis are not fully understood. Transcriptomic studies may provide new insights into molecular pathways involved in the severe form of the disease. Methods Blood transcriptional levels were assessed in patients with cerebral malaria, non-cerebral malaria, or mild malaria by using microarray technology to look for gene expression profiles associated with clinical status. Multi-way ANOVA was used to extract differentially expressed genes. Network and pathways analyses were used to detect enrichment for biological pathways. Results We identified a set of 443 genes that were differentially expressed in the three patient groups after applying a false discovery rate of 10%. Since the cerebral patients displayed a particular transcriptional pattern, we focused our analysis on the differences between cerebral malaria patients and mild malaria patients. We further found 842 differentially expressed genes after applying a false discovery rate of 10%. Unsupervised hierarchical clustering of cerebral malaria-informative genes led to clustering of the cerebral malaria patients. The support vector machine method allowed us to correctly classify five out of six cerebral malaria patients and six of six mild malaria patients. Furthermore, the products of the differentially expressed genes were mapped onto a human protein-protein network. This led to the identification of the proteins with the highest number of interactions, including GSK3B, RELA, and APP. The enrichment analysis of the gene functional annotation indicates that genes involved in immune signalling pathways play a role in the occurrence of cerebral malaria. These include BCR-, TCR-, TLR-, cytokine-, FcεRI-, and FCGR- signalling pathways and natural killer cell cytotoxicity pathways, which are involved in the activation of immune cells. In addition, our results revealed an enrichment of genes involved in Alzheimer’s disease. Conclusions In the present study, we examine a set of genes whose expression differed in cerebral malaria patients and mild malaria patients. Moreover, our results provide new insights into the potential effect of the dysregulation of gene expression in immune pathways. Host genetic variation may partly explain such alteration of gene expression. Further studies are required to investigate this in African populations.
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Affiliation(s)
- Alassane Thiam
- Unité d'Immunogénétique, Institut Pasteur de Dakar, Dakar, Sénégal
| | - Michel Sanka
- Aix Marseille Univ, INSERM, TAGC UMR U1090, 163 Av de Luminy, 13288, Marseille, cedex 9, France
| | - Rokhaya Ndiaye Diallo
- Service de Génétique Humaine, Faculté de Médecine, de Pharmacie et d'Odontostomatologie, UCAD, Dakar, Sénégal
| | - Magali Torres
- Aix Marseille Univ, INSERM, TAGC UMR U1090, 163 Av de Luminy, 13288, Marseille, cedex 9, France
| | - Babacar Mbengue
- Service Immunologie, Faculte de Medecine, Université Cheikh Anta Diop de Dakar, Dakar, Sénégal
| | - Nicolas Fernandez Nunez
- Aix Marseille Univ, INSERM, TAGC UMR U1090, 163 Av de Luminy, 13288, Marseille, cedex 9, France
| | - Fatou Thiam
- Département de Génie chimique et biologie, Ecole Supérieure Polytechnique, Université Cheikh Anta Diop de Dakar, Dakar, Sénégal
| | - Gora Diop
- Unité d'Immunogénétique, Institut Pasteur de Dakar, Dakar, Sénégal.,Département de Biologie animale, Faculté des Sciences et Techniques, Université Cheikh Anta Diop de Dakar, Dakar, Sénégal
| | - Geneviève Victorero
- Aix Marseille Univ, INSERM, TAGC UMR U1090, 163 Av de Luminy, 13288, Marseille, cedex 9, France
| | - Catherine Nguyen
- Aix Marseille Univ, INSERM, TAGC UMR U1090, 163 Av de Luminy, 13288, Marseille, cedex 9, France
| | - Alioune Dieye
- Unité d'Immunogénétique, Institut Pasteur de Dakar, Dakar, Sénégal.,Service Immunologie, Faculte de Medecine, Université Cheikh Anta Diop de Dakar, Dakar, Sénégal
| | - Pascal Rihet
- Aix Marseille Univ, INSERM, TAGC UMR U1090, 163 Av de Luminy, 13288, Marseille, cedex 9, France.
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13
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Kimenyi KM, Wamae K, Ochola-Oyier LI. Understanding P. falciparum Asymptomatic Infections: A Proposition for a Transcriptomic Approach. Front Immunol 2019; 10:2398. [PMID: 31681289 PMCID: PMC6803459 DOI: 10.3389/fimmu.2019.02398] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 09/25/2019] [Indexed: 12/11/2022] Open
Abstract
Malaria is still a significant public health burden in the tropics. Infection with malaria causing parasites results in a wide range of clinical disease presentations, from severe to uncomplicated or mild, and in the poorly understood asymptomatic infections. The complexity of asymptomatic infections is due to the intricate interplay between factors derived from the human host, parasite, and environment. Asymptomatic infections often go undetected and provide a silent natural reservoir that sustains malaria transmission. This creates a major obstacle for malaria control and elimination efforts. Numerous studies have tried to characterize asymptomatic infections, unanimously revealing that host immunity is the underlying factor in the maintenance of these infections and in the risk of developing febrile malaria infections. An in-depth understanding of how host immunity and parasite factors interact to cause malaria disease tolerance is thus required. This review primarily focuses on understanding anti-inflammatory and pro-inflammatory responses to asymptomatic infections in malaria endemic areas, to present the view that it is potentially the shift in host immunity toward an anti-inflammatory profile that maintains asymptomatic infections after multiple exposures to malaria. Conversely, symptomatic infections are skewed toward a pro-inflammatory immune profile. Moreover, we propose that these infections can be better interrogated using next generation sequencing technologies, in particular RNA sequencing (RNA-seq), to investigate the immune system using the transcriptome sampled during a clearly defined asymptomatic infection.
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Affiliation(s)
- Kelvin M Kimenyi
- KEMRI-Wellcome Trust Research Programme, CGMRC, Kilifi, Kenya.,Centre for Biotechnology and Bioinformatics, University of Nairobi, Nairobi, Kenya
| | - Kevin Wamae
- KEMRI-Wellcome Trust Research Programme, CGMRC, Kilifi, Kenya
| | - Lynette Isabella Ochola-Oyier
- KEMRI-Wellcome Trust Research Programme, CGMRC, Kilifi, Kenya.,Pwani University Bioscience Research Centre, Pwani University, Kilifi, Kenya
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14
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Hoo R, Bruske E, Dimonte S, Zhu L, Mordmüller B, Sim BKL, Kremsner PG, Hoffman SL, Bozdech Z, Frank M, Preiser PR. Transcriptome profiling reveals functional variation in Plasmodium falciparum parasites from controlled human malaria infection studies. EBioMedicine 2019; 48:442-452. [PMID: 31521613 PMCID: PMC6838377 DOI: 10.1016/j.ebiom.2019.09.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 08/29/2019] [Accepted: 09/01/2019] [Indexed: 11/03/2022] Open
Abstract
BACKGROUND The transcriptome of Plasmodium falciparum clinical isolates varies according to strain, mosquito bites, disease severity and clinical history. Therefore, it remains a challenge to directly interpret the parasite's transcriptomic information into a more general biological signature in a natural human malaria infection. These confounding variations can be potentially overcome with parasites derived from controlled-human malaria infection (CHMI) studies. METHODS We performed CHMI studies in healthy and immunologically naïve volunteers receiving the same P. falciparum strain ((Sanaria® PfSPZ Challenge (NF54)), but with different sporozoite dosage and route of infection. Parasites isolated from these volunteers at the day of patency were subjected to in vitro culture for several generations and synchronized ring-stage parasites were subjected to transcriptome profiling. FINDINGS We observed clear deviations between CHMI-derived parasites from volunteer groups receiving different PfSPZ dose and route. CHMI-derived parasites and the pre-mosquito strain used for PfSPZ generation showed significant transcriptional variability for gene clusters associated with malaria pathogenesis, immune evasion and transmission. These transcriptional variation signature clusters were also observed in the transcriptome of P. falciparum isolates from acute clinical infections. INTERPRETATION Our work identifies a previously unrecognized transcriptional pattern in malaria infections in a non-immune background. Significant transcriptome heterogeneity exits between parasites derived from human infections and the pre-mosquito strain, implying that the malaria parasites undergo a change in functional state to adapt to its host environment. Our work also highlights the potential use of transcriptomics data from CHMI study advance our understanding of malaria parasite adaptation and transmission in humans. FUND: This work is supported by German Israeli Foundation, German ministry for education and research, MOE Tier 1 from the Singapore Ministry of Education Academic Research Fund, Singapore Ministry of Health's National Medical Research Council, National Institute of Allergy and Infectious Diseases, National Institutes of Health, USA and the German Centre for Infection Research (Deutsches Zentrum für Infektionsforschung-DZIF).
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Affiliation(s)
- Regina Hoo
- School of Biological Sciences, Nanyang Technological University, Singapore
| | - Ellen Bruske
- Institute of Tropical Medicine, Wilhelmstr. 27, University of Tübingen, 72074 Tübingen, Germany
| | - Sandra Dimonte
- Institute of Tropical Medicine, Wilhelmstr. 27, University of Tübingen, 72074 Tübingen, Germany
| | - Lei Zhu
- School of Biological Sciences, Nanyang Technological University, Singapore
| | - Benjamin Mordmüller
- Institute of Tropical Medicine, Wilhelmstr. 27, University of Tübingen, 72074 Tübingen, Germany; German Center for Infection Research, partner site Tübingen, Germany
| | - B Kim Lee Sim
- Sanaria Inc, 9800 Medical Center Dr A209, Rockville, MD 20850, USA
| | - Peter G Kremsner
- Institute of Tropical Medicine, Wilhelmstr. 27, University of Tübingen, 72074 Tübingen, Germany; Centre de Recherches Médicales de Lambaréné, BP 242 Lambaréné, Gabon
| | | | - Zbynek Bozdech
- School of Biological Sciences, Nanyang Technological University, Singapore
| | - Matthias Frank
- Institute of Tropical Medicine, Wilhelmstr. 27, University of Tübingen, 72074 Tübingen, Germany.
| | - Peter R Preiser
- School of Biological Sciences, Nanyang Technological University, Singapore.
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15
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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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16
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Bah SY, Morang'a CM, Kengne-Ouafo JA, Amenga-Etego L, Awandare GA. Highlights on the Application of Genomics and Bioinformatics in the Fight Against Infectious Diseases: Challenges and Opportunities in Africa. Front Genet 2018; 9:575. [PMID: 30538723 PMCID: PMC6277583 DOI: 10.3389/fgene.2018.00575] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 11/08/2018] [Indexed: 01/18/2023] Open
Abstract
Genomics and bioinformatics are increasingly contributing to our understanding of infectious diseases caused by bacterial pathogens such as Mycobacterium tuberculosis and parasites such as Plasmodium falciparum. This ranges from investigations of disease outbreaks and pathogenesis, host and pathogen genomic variation, and host immune evasion mechanisms to identification of potential diagnostic markers and vaccine targets. High throughput genomics data generated from pathogens and animal models can be combined with host genomics and patients’ health records to give advice on treatment options as well as potential drug and vaccine interactions. However, despite accounting for the highest burden of infectious diseases, Africa has the lowest research output on infectious disease genomics. Here we review the contributions of genomics and bioinformatics to the management of infectious diseases of serious public health concern in Africa including tuberculosis (TB), dengue fever, malaria and filariasis. Furthermore, we discuss how genomics and bioinformatics can be applied to identify drug and vaccine targets. We conclude by identifying challenges to genomics research in Africa and highlighting how these can be overcome where possible.
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Affiliation(s)
- Saikou Y Bah
- West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, Accra, Ghana.,Vaccine and Immunity Theme, MRC Unit The Gambia at London School of Hygiene & Tropical Medicine, Banjul, Gambia
| | - Collins Misita Morang'a
- West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, Accra, Ghana
| | - Jonas A Kengne-Ouafo
- West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, Accra, Ghana
| | - Lucas Amenga-Etego
- West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, Accra, Ghana
| | - Gordon A Awandare
- West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, Accra, Ghana
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17
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Lee HJ, Georgiadou A, Otto TD, Levin M, Coin LJ, Conway DJ, Cunnington AJ. Transcriptomic Studies of Malaria: a Paradigm for Investigation of Systemic Host-Pathogen Interactions. Microbiol Mol Biol Rev 2018; 82:e00071-17. [PMID: 29695497 PMCID: PMC5968457 DOI: 10.1128/mmbr.00071-17] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Transcriptomics, the analysis of genome-wide RNA expression, is a common approach to investigate host and pathogen processes in infectious diseases. Technical and bioinformatic advances have permitted increasingly thorough analyses of the association of RNA expression with fundamental biology, immunity, pathogenesis, diagnosis, and prognosis. Transcriptomic approaches can now be used to realize a previously unattainable goal, the simultaneous study of RNA expression in host and pathogen, in order to better understand their interactions. This exciting prospect is not without challenges, especially as focus moves from interactions in vitro under tightly controlled conditions to tissue- and systems-level interactions in animal models and natural and experimental infections in humans. Here we review the contribution of transcriptomic studies to the understanding of malaria, a parasitic disease which has exerted a major influence on human evolution and continues to cause a huge global burden of disease. We consider malaria a paradigm for the transcriptomic assessment of systemic host-pathogen interactions in humans, because much of the direct host-pathogen interaction occurs within the blood, a readily sampled compartment of the body. We illustrate lessons learned from transcriptomic studies of malaria and how these lessons may guide studies of host-pathogen interactions in other infectious diseases. We propose that the potential of transcriptomic studies to improve the understanding of malaria as a disease remains partly untapped because of limitations in study design rather than as a consequence of technological constraints. Further advances will require the integration of transcriptomic data with analytical approaches from other scientific disciplines, including epidemiology and mathematical modeling.
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Affiliation(s)
- Hyun Jae Lee
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Australia
| | | | - Thomas D Otto
- Centre of Immunobiology, University of Glasgow, Glasgow, United Kingdom
| | - Michael Levin
- Section of Paediatrics, Imperial College, London, United Kingdom
| | - Lachlan J Coin
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Australia
| | - David J Conway
- Department of Pathogen Molecular Biology, London School of Hygiene and Tropical Medicine, London, United Kingdom
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18
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Smith ML, Styczynski MP. Systems Biology-Based Investigation of Host-Plasmodium Interactions. Trends Parasitol 2018; 34:617-632. [PMID: 29779985 DOI: 10.1016/j.pt.2018.04.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Revised: 04/10/2018] [Accepted: 04/16/2018] [Indexed: 12/20/2022]
Abstract
Malaria is a serious, complex disease caused by parasites of the genus Plasmodium. Plasmodium parasites affect multiple tissues as they evade immune responses, replicate, sexually reproduce, and transmit between vertebrate and invertebrate hosts. The explosion of omics technologies has enabled large-scale collection of Plasmodium infection data, revealing systems-scale patterns, mechanisms of pathogenesis, and the ways that host and pathogen affect each other. Here, we provide an overview of recent efforts using systems biology approaches to study host-Plasmodium interactions and the biological themes that have emerged from these efforts. We discuss some of the challenges in using systems biology for this goal, key research efforts needed to address those issues, and promising future malaria applications of systems biology.
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Affiliation(s)
- Maren L Smith
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA; Malaria Host-Pathogen Interaction Center, Emory University, Atlanta, GA 30322, USA
| | - Mark P Styczynski
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA; Malaria Host-Pathogen Interaction Center, Emory University, Atlanta, GA 30322, USA.
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19
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The Plasmodium falciparum transcriptome in severe malaria reveals altered expression of genes involved in important processes including surface antigen-encoding var genes. PLoS Biol 2018; 16:e2004328. [PMID: 29529020 PMCID: PMC5864071 DOI: 10.1371/journal.pbio.2004328] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Revised: 03/22/2018] [Accepted: 02/16/2018] [Indexed: 01/13/2023] Open
Abstract
Within the human host, the malaria parasite Plasmodium falciparum is exposed to multiple selection pressures. The host environment changes dramatically in severe malaria, but the extent to which the parasite responds to-or is selected by-this environment remains unclear. From previous studies, the parasites that cause severe malaria appear to increase expression of a restricted but poorly defined subset of the PfEMP1 variant, surface antigens. PfEMP1s are major targets of protective immunity. Here, we used RNA sequencing (RNAseq) to analyse gene expression in 44 parasite isolates that caused severe and uncomplicated malaria in Papuan patients. The transcriptomes of 19 parasite isolates associated with severe malaria indicated that these parasites had decreased glycolysis without activation of compensatory pathways; altered chromatin structure and probably transcriptional regulation through decreased histone methylation; reduced surface expression of PfEMP1; and down-regulated expression of multiple chaperone proteins. Our RNAseq also identified novel associations between disease severity and PfEMP1 transcripts, domains, and smaller sequence segments and also confirmed all previously reported associations between expressed PfEMP1 sequences and severe disease. These findings will inform efforts to identify vaccine targets for severe malaria and also indicate how parasites adapt to-or are selected by-the host environment in severe malaria.
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20
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Golenser J, Buchholz V, Bagheri A, Nasereddin A, Dzikowski R, Guo J, Hunt NH, Eyal S, Vakruk N, Greiner A. Controlled release of artemisone for the treatment of experimental cerebral malaria. Parasit Vectors 2017; 10:117. [PMID: 28249591 PMCID: PMC5333427 DOI: 10.1186/s13071-017-2018-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Accepted: 02/07/2017] [Indexed: 11/24/2022] Open
Abstract
Background Cerebral malaria (CM) is a leading cause of malarial mortality resulting from infection by Plasmodium falciparum. Treatment commonly involves adjunctive care and injections or transfusion of artemisinins. All artemisinins that are in current use are metabolized to dihydroxyartemisinin (DHA), to which there is already some parasite resistance. We used artemisone, a derivative that does not convert to DHA, has improved pharmacokinetics and anti-plasmodial activity and is also anti-inflammatory (an advantage given the immunopathological nature of CM). Methods We examined controlled artemisone release from biodegradable polymers in a mouse CM model. This would improve treatment by exposing the parasites for a longer period to a non-toxic drug concentration, high enough to eliminate the pathogen and prevent CM. The preparations were inserted into mice as prophylaxis, early or late treatment in the disease course. Results The most efficient formulation was a rigid polymer, containing 80 mg/kg artemisone, which cured all of the mice when used as early treatment and 60% of the mice when used as a very late treatment (at which stage all control mice would die of CM within 24 h). In those mice that were not completely cured, relapse followed a latent period of more than seven days. Prophylactic treatment four days prior to the infection prevented CM. We also measured the amount of artemisone released from the rigid polymers using a bioassay with cultured P. falciparum. Significant amounts of artemisone were released throughout at least ten days, in line with the in vivo prophylactic results. Conclusions Overall, we demonstrate, as a proof-of-concept, a controlled-sustained release system of artemisone for treatment of CM. Mice were cured or if treated at a very late stage of the disease, depicted a delay of a week before death. This delay would enable a considerable time window for exact diagnosis and appropriate additional treatment. Identical methods could be used for other parasites that are sensitive to artemisinins (e.g. Toxoplasma gondii and Neospora caninum).
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Affiliation(s)
- Jacob Golenser
- Department of Microbiology and Molecular Genetics, The Kuvin Center for the Study of Infectious and Tropical Diseases, The Hebrew University of Jerusalem (HU)-Hadassah Medical School (HMS), Jerusalem, Israel.
| | - Viola Buchholz
- Macromolecular Chemistry II, University of Bayreuth, Universitätsstrasse 30, Bayreuth, Germany
| | - Amir Bagheri
- Macromolecular Chemistry II, University of Bayreuth, Universitätsstrasse 30, Bayreuth, Germany
| | - Abed Nasereddin
- Department of Microbiology and Molecular Genetics, The Kuvin Center for the Study of Infectious and Tropical Diseases, The Hebrew University of Jerusalem (HU)-Hadassah Medical School (HMS), Jerusalem, Israel.,Al-Quds University, Abu Dis, The Palestinian Authority
| | - Ron Dzikowski
- Department of Microbiology and Molecular Genetics, The Kuvin Center for the Study of Infectious and Tropical Diseases, The Hebrew University of Jerusalem (HU)-Hadassah Medical School (HMS), Jerusalem, Israel
| | - Jintao Guo
- Department of Pathology and Bosch Institute, The University of Sydney, Sydney, Australia.,State Key Laboratory of Respiratory Diseases, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China
| | - Nicholas H Hunt
- Department of Pathology and Bosch Institute, The University of Sydney, Sydney, Australia
| | - Sara Eyal
- Institute of Drug Research, School of Pharmacy, HU-HMS, Jerusalem, Israel
| | - Natalia Vakruk
- Department of Microbiology and Molecular Genetics, The Kuvin Center for the Study of Infectious and Tropical Diseases, The Hebrew University of Jerusalem (HU)-Hadassah Medical School (HMS), Jerusalem, Israel.,Institute of Drug Research, School of Pharmacy, HU-HMS, Jerusalem, Israel
| | - Andreas Greiner
- Macromolecular Chemistry II, University of Bayreuth, Universitätsstrasse 30, Bayreuth, Germany
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Cytoadhesion to gC1qR through Plasmodium falciparum Erythrocyte Membrane Protein 1 in Severe Malaria. PLoS Pathog 2016; 12:e1006011. [PMID: 27835682 PMCID: PMC5106025 DOI: 10.1371/journal.ppat.1006011] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2016] [Accepted: 10/19/2016] [Indexed: 11/19/2022] Open
Abstract
Cytoadhesion of Plasmodium falciparum infected erythrocytes to gC1qR has been associated with severe malaria, but the parasite ligand involved is currently unknown. To assess if binding to gC1qR is mediated through the P. falciparum erythrocyte membrane protein 1 (PfEMP1) family, we analyzed by static binding assays and qPCR the cytoadhesion and var gene transcriptional profile of 86 P. falciparum isolates from Mozambican children with severe and uncomplicated malaria, as well as of a P. falciparum 3D7 line selected for binding to gC1qR (Pf3D7gC1qR). Transcript levels of DC8 correlated positively with cytoadhesion to gC1qR (rho = 0.287, P = 0.007), were higher in isolates from children with severe anemia than with uncomplicated malaria, as well as in isolates from Europeans presenting a first episode of malaria (n = 21) than Mozambican adults (n = 25), and were associated with an increased IgG recognition of infected erythrocytes by flow cytometry. Pf3D7gC1qR overexpressed the DC8 type PFD0020c (5.3-fold transcript levels relative to Seryl-tRNA-synthetase gene) compared to the unselected line (0.001-fold). DBLβ12 from PFD0020c bound to gC1qR in ELISA-based binding assays and polyclonal antibodies against this domain were able to inhibit binding to gC1qR of Pf3D7gC1qR and four Mozambican P. falciparum isolates by 50%. Our results show that DC8-type PfEMP1s mediate binding to gC1qR through conserved surface epitopes in DBLβ12 domain which can be inhibited by strain-transcending functional antibodies. This study supports a key role for gC1qR in malaria-associated endovascular pathogenesis and suggests the feasibility of designing interventions against severe malaria targeting this specific interaction. Plasmodium falciparum sequesters in vital organs. This phenomenon mediated by cytoadhesion of infected-erythrocytes to host receptors in the microvasculature, contributes to the development of severe malaria. Although cytoadhesion to Endothelial Protein-C Receptor has a central role in severe malaria, other host receptors are also likely to be involved. Our results generated by the analysis of P. falciparum isolates from Mozambican patients and laboratory parasite lines indicate that a specific domain (DBLβ12) from DC8-type PfEMP1s can bind to the human receptor gC1qR, previously associated with severe malaria. Our findings revealed that antibodies against PfEMP1 could provide strain-transcending inhibition of gC1qR-binding. Overall, these results support a key role for the adhesion to gC1qR in malaria-associated endovascular pathogenesis and the feasibility of new interventions targeting this specific interaction.
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22
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Plasmodium Helical Interspersed Subtelomeric (PHIST) Proteins, at the Center of Host Cell Remodeling. Microbiol Mol Biol Rev 2016; 80:905-27. [PMID: 27582258 DOI: 10.1128/mmbr.00014-16] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
During the asexual cycle, Plasmodium falciparum extensively remodels the human erythrocyte to make it a suitable host cell. A large number of exported proteins facilitate this remodeling process, which causes erythrocytes to become more rigid, cytoadherent, and permeable for nutrients and metabolic products. Among the exported proteins, a family of 89 proteins, called the Plasmodium helical interspersed subtelomeric (PHIST) protein family, has been identified. While also found in other Plasmodium species, the PHIST family is greatly expanded in P. falciparum. Although a decade has passed since their first description, to date, most PHIST proteins remain uncharacterized and are of unknown function and localization within the host cell, and there are few data on their interactions with other host or parasite proteins. However, over the past few years, PHIST proteins have been mentioned in the literature at an increasing rate owing to their presence at various localizations within the infected erythrocyte. Expression of PHIST proteins has been implicated in molecular and cellular processes such as the surface display of PfEMP1, gametocytogenesis, changes in cell rigidity, and also cerebral and pregnancy-associated malaria. Thus, we conclude that PHIST proteins are central to host cell remodeling, but despite their obvious importance in pathology, PHIST proteins seem to be understudied. Here we review current knowledge, shed light on the definition of PHIST proteins, and discuss these proteins with respect to their localization and probable function. We take into consideration interaction studies, microarray analyses, or data from blood samples from naturally infected patients to combine all available information on this protein family.
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23
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Bertin GI, Sabbagh A, Argy N, Salnot V, Ezinmegnon S, Agbota G, Ladipo Y, Alao JM, Sagbo G, Guillonneau F, Deloron P. Proteomic analysis of Plasmodium falciparum parasites from patients with cerebral and uncomplicated malaria. Sci Rep 2016; 6:26773. [PMID: 27245217 PMCID: PMC4887788 DOI: 10.1038/srep26773] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Accepted: 05/05/2016] [Indexed: 01/31/2023] Open
Abstract
Plasmodium falciparum is responsible of severe malaria, including cerebral malaria (CM). During its intra-erythrocytic maturation, parasite-derived proteins are expressed, exported and presented at the infected erythrocyte membrane. To identify new CM-specific parasite membrane proteins, we conducted a mass spectrometry-based proteomic study and compared the protein expression profiles between 9 CM and 10 uncomplicated malaria (UM) samples. Among the 1097 Plasmodium proteins identified, we focused on the 499 membrane-associated and hypothetical proteins for comparative analysis. Filter-based feature selection methods combined with supervised data analysis identified a subset of 29 proteins distinguishing CM and UM samples with high classification accuracy. A hierarchical clustering analysis of these 29 proteins based on the similarity of their expression profiles revealed two clusters of 15 and 14 proteins, respectively under- and over-expressed in CM. Among the over-expressed proteins, the MESA protein is expressed at the erythrocyte membrane, involved in proteins trafficking and in the export of variant surface antigens (VSAs), but without antigenic function. Antigen 332 protein is exported at the erythrocyte, also involved in protein trafficking and in VSAs export, and exposed to the immune system. Our proteomics data demonstrate an association of selected proteins in the pathophysiology of CM.
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Affiliation(s)
- Gwladys I Bertin
- Institut de Recherche pour le Développement (IRD), UMR216 - MERIT, Paris, France.,COMUE Sorbonne Paris Cité, Faculté de Pharmacie de Paris, Paris Descartes University, Paris 75006, France
| | - Audrey Sabbagh
- Institut de Recherche pour le Développement (IRD), UMR216 - MERIT, Paris, France.,COMUE Sorbonne Paris Cité, Faculté de Pharmacie de Paris, Paris Descartes University, Paris 75006, France
| | - Nicolas Argy
- Institut de Recherche pour le Développement (IRD), UMR216 - MERIT, Paris, France.,COMUE Sorbonne Paris Cité, Faculté de Pharmacie de Paris, Paris Descartes University, Paris 75006, France.,Parasitology laboratory, Bichat-Claude Bernard hospital, Paris 75018, France.,French national reference center of malaria laboratory, Bichat-Claude Bernard hospital, Paris 75018, France
| | - Virginie Salnot
- COMUE Sorbonne Paris Cité, Faculté de Pharmacie de Paris, Paris Descartes University, Paris 75006, France.,3P5 Proteomics facility, Université Paris Descartes, Paris, France
| | - Sem Ezinmegnon
- Centre d'Étude et de Recherche sur le Paludisme Associé à la Grossesse et l'Enfance (CERPAGE), Cotonou, Benin
| | - Gino Agbota
- Institut de Recherche pour le Développement (IRD), UMR216 - MERIT, Paris, France.,COMUE Sorbonne Paris Cité, Faculté de Pharmacie de Paris, Paris Descartes University, Paris 75006, France.,Centre d'Étude et de Recherche sur le Paludisme Associé à la Grossesse et l'Enfance (CERPAGE), Cotonou, Benin
| | - Yélé Ladipo
- Paediatric Department, Mother and child hospital (HOMEL), Cotonou, Benin
| | - Jules M Alao
- Paediatric Department, Mother and child hospital (HOMEL), Cotonou, Benin
| | - Gratien Sagbo
- Paediatric Department, Centre National Hospitalo-Universitaire (CNHU), Cotonou, Benin
| | - François Guillonneau
- COMUE Sorbonne Paris Cité, Faculté de Pharmacie de Paris, Paris Descartes University, Paris 75006, France.,3P5 Proteomics facility, Université Paris Descartes, Paris, France
| | - Philippe Deloron
- Institut de Recherche pour le Développement (IRD), UMR216 - MERIT, Paris, France.,COMUE Sorbonne Paris Cité, Faculté de Pharmacie de Paris, Paris Descartes University, Paris 75006, France
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Mosquito Passage Dramatically Changes var Gene Expression in Controlled Human Plasmodium falciparum Infections. PLoS Pathog 2016; 12:e1005538. [PMID: 27070311 PMCID: PMC4829248 DOI: 10.1371/journal.ppat.1005538] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 03/10/2016] [Indexed: 11/19/2022] Open
Abstract
Virulence of the most deadly malaria parasite Plasmodium falciparum is linked to the variant surface antigen PfEMP1, which is encoded by about 60 var genes per parasite genome. Although the expression of particular variants has been associated with different clinical outcomes, little is known about var gene expression at the onset of infection. By analyzing controlled human malaria infections via quantitative real-time PCR, we show that parasite populations from 18 volunteers expressed virtually identical transcript patterns that were dominated by the subtelomeric var gene group B and, to a lesser extent, group A. Furthermore, major changes in composition and frequency of var gene transcripts were detected between the parental parasite culture that was used to infect mosquitoes and Plasmodia recovered from infected volunteers, suggesting that P. falciparum resets its var gene expression during mosquito passage and starts with the broad expression of a specific subset of var genes when entering the human blood phase.
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Abstract
The Plasmodium falciparum erythrocyte membrane protein 1 antigens that are inserted onto the surface of P. falciparum infected erythrocytes play a key role both in the pathology of severe malaria and as targets of naturally acquired immunity. They might be considered unlikely vaccine targets because they are extremely diverse. However, several lines of evidence suggest that underneath this molecular diversity there are a restricted set of epitopes which may act as effective targets for a vaccine against severe malaria. Here we review some of the recent developments in this area of research, focusing on work that has assessed the potential of these molecules as possible vaccine targets.
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