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Riedmiller I, Fougeroux C, Jensen RW, Kana IH, Sander AF, Theander TG, Lavstsen T, Turner L. Mosaic and cocktail capsid-virus-like particle vaccines for induction of antibodies against the EPCR-binding CIDRα1 domain of PfEMP1. PLoS One 2024; 19:e0302243. [PMID: 39046960 PMCID: PMC11268589 DOI: 10.1371/journal.pone.0302243] [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: 03/30/2024] [Accepted: 07/08/2024] [Indexed: 07/27/2024] Open
Abstract
The sequestration of Plasmodium falciparum-infected erythrocytes to the host endothelium is central to the pathogenesis of malaria. The sequestration is mediated by the parasite´s diverse Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) variants, which bind select human receptors on the endothelium. Severe malaria is associated with PfEMP1 binding human endothelial protein C receptor (EPCR) via their CIDRα1 domains. Antibodies binding and inhibiting across the sequence diverse CIDRα1 domains are likely important in acquired immunity against severe malaria. In this study, we explored if immunization with AP205 bacteriophage capsid-virus-like particles (cVLPs) presenting a mosaic of diverse CIDRα1 protein variants would stimulate broadly reactive and inhibitory antibody responses in mice. Three different mosaic cVLP vaccines each composed of five CIDRα1 protein variants with varying degrees of sequence conservation of residues at and near the EPCR binding site, were tested. All mosaic cVLP vaccines induced functional antibodies comparable to those induced by matched cocktails of cVLPs decorated with the single CIDRα1 variant. No broadly reactive responses were observed. However, the vaccines did induce some cross-reactivity and inhibition within the CIDRα1 subclasses included in the vaccines, demonstrating potential use of the cVLP vaccine platform for the design of multivalent vaccines.
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Affiliation(s)
- Ilary Riedmiller
- Department of Immunology and Microbiology, Centre for translational Medicine and Parasitology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | | | - Rasmus W. Jensen
- Department of Immunology and Microbiology, Centre for translational Medicine and Parasitology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Ikhlaq H. Kana
- Department of Immunology and Microbiology, Centre for translational Medicine and Parasitology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | | | - Thor G. Theander
- Department of Immunology and Microbiology, Centre for translational Medicine and Parasitology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Thomas Lavstsen
- Department of Immunology and Microbiology, Centre for translational Medicine and Parasitology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Louise Turner
- Department of Immunology and Microbiology, Centre for translational Medicine and Parasitology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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2
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McLean FE, Azasi Y, Sutherland C, Toboh E, Ansong D, Agbenyega T, Awandare G, Rowe JA. Detection of naturally acquired, strain-transcending antibodies against rosetting Plasmodium falciparum strains in humans. Infect Immun 2024; 92:e0001524. [PMID: 38842304 PMCID: PMC11238554 DOI: 10.1128/iai.00015-24] [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: 01/11/2024] [Accepted: 04/29/2024] [Indexed: 06/07/2024] Open
Abstract
Strain-transcending antibodies against virulence-associated subsets of P. falciparum-infected erythrocyte surface antigens could protect children from severe malaria. However, the evidence supporting the existence of such antibodies is incomplete and inconsistent. One subset of surface antigens associated with severe malaria, rosette-mediating Plasmodium falciparum Erythrocyte Membrane Protein one (PfEMP1) variants, cause infected erythrocytes to bind to uninfected erythrocytes to form clusters of cells (rosettes) that contribute to microvascular obstruction and pathology. Here, we tested plasma from 80 individuals living in malaria-endemic regions for IgG recognition of the surface of four P. falciparum rosetting strains using flow cytometry. Broadly reactive plasma samples were then used in antibody elution experiments in which intact IgG was eluted from the surface of infected erythrocytes and transferred to heterologous rosetting strains to look for strain-transcending antibodies. We found that seroprevalence (percentage of positive plasma samples) against allopatric rosetting strains was high in adults (63%-93%) but lower in children (13%-48%). Strain-transcending antibodies were present in nine out of eleven eluted antibody experiments, with six of these recognizing multiple heterologous rosetting parasite strains. One eluate had rosette-disrupting activity against heterologous strains, suggesting PfEMP1 as the likely target of the strain-transcending antibodies. Naturally acquired strain-transcending antibodies to rosetting P. falciparum strains in humans have not been directly demonstrated previously. Their existence suggests that such antibodies could play a role in clinical protection and raises the possibility that conserved epitopes recognized by strain-transcending antibodies could be targeted therapeutically by monoclonal antibodies or vaccines.
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Affiliation(s)
- Florence E. McLean
- Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Yvonne Azasi
- Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Cameron Sutherland
- Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | | | - Daniel Ansong
- Kwame Nkrumah University of Science and Technology, School of Medical Sciences, Kumasi, Ghana
- Departments of Child Health and Medicine, Komfo Anokye Teaching Hospital, Kumasi, Ghana
- Malaria Research Centre, Agogo, Ghana
| | - Tsiri Agbenyega
- Kwame Nkrumah University of Science and Technology, School of Medical Sciences, Kumasi, Ghana
- Departments of Child Health and Medicine, Komfo Anokye Teaching Hospital, Kumasi, Ghana
- Malaria Research Centre, Agogo, Ghana
| | - Gordon Awandare
- West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, Legon, Ghana
| | - J. Alexandra Rowe
- Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
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3
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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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4
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Reyes RA, Turner L, Ssewanyana I, Jagannathan P, Feeney ME, Lavstsen T, Greenhouse B, Bol S, Bunnik EM. Differences in phenotype between long-lived memory B cells against Plasmodium falciparum merozoite antigens and variant surface antigens. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.01.596978. [PMID: 38895251 PMCID: PMC11185507 DOI: 10.1101/2024.06.01.596978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/21/2024]
Abstract
Plasmodium falciparum infections elicit strong humoral immune responses to two main groups of antigens expressed by blood-stage parasites: merozoite antigens that are involved in the erythrocyte invasion process and variant surface antigens that mediate endothelial sequestration of infected erythrocytes. Long-lived B cells against both antigen classes can be detected in the circulation for years after exposure, but have not been directly compared. Here, we studied the phenotype of long-lived memory and atypical B cells to merozoite antigens (MSP1 and AMA1) and variant surface antigens (the CIDRα1 domain of PfEMP1) in Ugandan adults before and after local reduction of P. falciparum transmission. After a median of 1.7 years without P. falciparum infections, the percentage of antigen-specific activated B cells declined, but long-lived antigen-specific B cells were still detectable in all individuals. The majority of MSP1/AMA1-specific B cells were CD95+CD11c+ memory B cells, which are primed for rapid differentiation into antibody-secreting cells, and FcRL5-T-bet- atypical B cells. On the other hand, most CIDRα1-specific B cells were CD95-CD11c- memory B cells. CIDRα1-specific B cells were also enriched among a subset of atypical B cells that seem poised for antigen presentation. These results point to differences in how these antigens are recognized or processed by the immune system and how P. falciparum-specific B cells will respond upon re-infection.
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Affiliation(s)
- Raphael A Reyes
- Department of Microbiology, Immunology & Molecular Genetics, Long School of Medicine, The University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - Louise Turner
- Centre for translational Medicine & Parasitology, Department of Immunology and Microbiology, University of Copenhagen, and Department of Infectious Diseases, Righospitalet, Copenhagen, Denmark
| | | | - Prasanna Jagannathan
- Department of Medicine, Division of Infectious Diseases, Stanford University, Stanford, CA, USA
- Department of Microbiology & Immunology, Stanford University, Stanford, CA, USA
| | - Margaret E. Feeney
- Department of Pediatrics, University of California San Francisco, San Francisco, CA, USA
- Department of Medicine, University of California San Francisco, San Francisco, CA, USA
| | - Thomas Lavstsen
- Centre for translational Medicine & Parasitology, Department of Immunology and Microbiology, University of Copenhagen, and Department of Infectious Diseases, Righospitalet, Copenhagen, Denmark
| | - Bryan Greenhouse
- Department of Medicine, University of California San Francisco, San Francisco, CA, USA
| | - Sebastiaan Bol
- Department of Microbiology, Immunology & Molecular Genetics, Long School of Medicine, The University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - Evelien M Bunnik
- Department of Microbiology, Immunology & Molecular Genetics, Long School of Medicine, The University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
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5
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Reyes RA, Raghavan SSR, Hurlburt NK, Introini V, Kana IH, Jensen RW, Martinez-Scholze E, Gestal-Mato M, Bau CB, Fernández-Quintero ML, Loeffler JR, Ferguson JA, Lee WH, Martin GM, Theander TG, Ssewanyana I, Feeney ME, Greenhouse B, Bol S, Ward AB, Bernabeu M, Pancera M, Turner L, Bunnik EM, Lavstsen T. Broadly inhibitory antibodies against severe malaria virulence proteins. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.25.577124. [PMID: 38328068 PMCID: PMC10849712 DOI: 10.1101/2024.01.25.577124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
Plasmodium falciparum pathology is driven by the accumulation of parasite-infected erythrocytes in microvessels. This process is mediated by the parasite's polymorphic erythrocyte membrane protein 1 (PfEMP1) adhesion proteins. A subset of PfEMP1 variants that bind human endothelial protein C receptor (EPCR) through their CIDRα1 domains is responsible for severe malaria pathogenesis. A longstanding question is whether individual antibodies can recognize the large repertoire of circulating PfEMP1 variants. Here, we describe two broadly reactive and binding-inhibitory human monoclonal antibodies against CIDRα1. The antibodies isolated from two different individuals exhibited a similar and consistent EPCR-binding inhibition of 34 CIDRα1 domains, representing five of the six subclasses of CIDRα1. Both antibodies inhibited EPCR binding of both recombinant full-length and native PfEMP1 proteins as well as parasite sequestration in bioengineered 3D brain microvessels under physiologically relevant flow conditions. Structural analyses of the two antibodies in complex with two different CIDRα1 antigen variants reveal similar binding mechanisms that depend on interactions with three highly conserved amino acid residues of the EPCR-binding site in CIDRα1. These broadly reactive antibodies likely represent a common mechanism of acquired immunity to severe malaria and offer novel insights for the design of a vaccine or treatment targeting severe malaria.
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Affiliation(s)
- Raphael A. Reyes
- Department of Microbiology, Immunology and Molecular Genetics, Long School of Medicine, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Sai Sundar Rajan Raghavan
- Centre for translational Medicine & Parasitology, Department of Immunology and Microbiology, University of Copenhagen and Department of Infectious Diseases, Righospitalet, Copenhagen, Denmark
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Nicholas K. Hurlburt
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Center, Seattle, WA 98109, USA
| | - Viola Introini
- European Molecular Biology Laboratory (EMBL) Barcelona, Barcelona 08003, Spain
| | - Ikhlaq Hussain Kana
- Centre for translational Medicine & Parasitology, Department of Immunology and Microbiology, University of Copenhagen and Department of Infectious Diseases, Righospitalet, Copenhagen, Denmark
| | - Rasmus W. Jensen
- Centre for translational Medicine & Parasitology, Department of Immunology and Microbiology, University of Copenhagen and Department of Infectious Diseases, Righospitalet, Copenhagen, Denmark
| | - Elizabeth Martinez-Scholze
- Department of Microbiology, Immunology and Molecular Genetics, Long School of Medicine, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Maria Gestal-Mato
- European Molecular Biology Laboratory (EMBL) Barcelona, Barcelona 08003, Spain
| | | | | | - Johannes R. Loeffler
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - James Alexander Ferguson
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Wen-Hsin Lee
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Greg Michael Martin
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Thor G. Theander
- Centre for translational Medicine & Parasitology, Department of Immunology and Microbiology, University of Copenhagen and Department of Infectious Diseases, Righospitalet, Copenhagen, Denmark
| | | | - Margaret E. Feeney
- Department of Medicine, University of California San Francisco, San Francisco, CA 94110, USA
- Department of Pediatrics, University of California San Francisco, San Francisco, CA 94110, USA
| | - Bryan Greenhouse
- Department of Medicine, University of California San Francisco, San Francisco, CA 94110, USA
| | - Sebastiaan Bol
- Department of Microbiology, Immunology and Molecular Genetics, Long School of Medicine, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Andrew B. Ward
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Maria Bernabeu
- European Molecular Biology Laboratory (EMBL) Barcelona, Barcelona 08003, Spain
| | - Marie Pancera
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Center, Seattle, WA 98109, USA
| | - Louise Turner
- Centre for translational Medicine & Parasitology, Department of Immunology and Microbiology, University of Copenhagen and Department of Infectious Diseases, Righospitalet, Copenhagen, Denmark
| | - Evelien M. Bunnik
- Department of Microbiology, Immunology and Molecular Genetics, Long School of Medicine, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Thomas Lavstsen
- Centre for translational Medicine & Parasitology, Department of Immunology and Microbiology, University of Copenhagen and Department of Infectious Diseases, Righospitalet, Copenhagen, Denmark
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6
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Gill J, Singh H, Sharma A. Profiles of global mutations in the human intercellular adhesion molecule-1 (ICAM-1) shed light on population-specific malaria susceptibility. BMC Genomics 2023; 24:773. [PMID: 38093209 PMCID: PMC10720214 DOI: 10.1186/s12864-023-09846-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Accepted: 11/27/2023] [Indexed: 12/17/2023] Open
Abstract
Plasmodium falciparum is responsible for malaria-related morbidity and mortality. PfEMP1 (P. falciparum erythrocyte membrane protein 1) mediates infected erythrocytes adhesion to various surface vascular receptors, including intercellular adhesion molecule-1 (ICAM-1), associating this interaction with severe malaria in several studies. Genetic variation in host ICAM-1 plays a significant role in determining susceptibility to malaria infection via clinical phenotypes such as the ICAM-1Kilifi variant which has been reported to be associated with susceptibility in populations. Our genomic and structural analysis of single nucleotide polymorphisms (SNPs) in ICAM-1 revealed 9 unique mutations each in its distinct A-type and BC-type PfEMP1 DBLβ-interacting regions. These mutations are noted in only a few field isolates and mainly in the African/African American population. The ICAM-1Kilifi variant lies in a flexible loop proximal to the DBLβ-interacting region. This analysis will assist in establishing functional correlations of reported global mutations via experimental and clinical studies and in the tailored design of population-specific genetic surveillance studies. Understanding host polymorphism as an evolutionary force in diverse populations can help to predict predisposition to disease severity and will contribute towards laying the framework for designing population-specific personalized medicines for severe malaria.
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Affiliation(s)
- Jasmita Gill
- ICMR-National Institute of Malaria Research, Sector-8 Dwarka, New Delhi, India.
| | - Himmat Singh
- ICMR-National Institute of Malaria Research, Sector-8 Dwarka, New Delhi, India
| | - Amit Sharma
- International Centre for Genetic Engineering and Biotechnology, New Delhi, India
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7
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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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8
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Hadjilaou A, Brandi J, Riehn M, Friese MA, Jacobs T. Pathogenetic mechanisms and treatment targets in cerebral malaria. Nat Rev Neurol 2023; 19:688-709. [PMID: 37857843 DOI: 10.1038/s41582-023-00881-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/11/2023] [Indexed: 10/21/2023]
Abstract
Malaria, the most prevalent mosquito-borne infectious disease worldwide, has accompanied humanity for millennia and remains an important public health issue despite advances in its prevention and treatment. Most infections are asymptomatic, but a small percentage of individuals with a heavy parasite burden develop severe malaria, a group of clinical syndromes attributable to organ dysfunction. Cerebral malaria is an infrequent but life-threatening complication of severe malaria that presents as an acute cerebrovascular encephalopathy characterized by unarousable coma. Despite effective antiparasite drug treatment, 20% of patients with cerebral malaria die from this disease, and many survivors of cerebral malaria have neurocognitive impairment. Thus, an important unmet clinical need is to rapidly identify people with malaria who are at risk of developing cerebral malaria and to develop preventive, adjunctive and neuroprotective treatments for cerebral malaria. This Review describes important advances in the understanding of cerebral malaria over the past two decades and discusses how these mechanistic insights could be translated into new therapies.
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Affiliation(s)
- Alexandros Hadjilaou
- Protozoen Immunologie, Bernhard-Nocht-Institut für Tropenmedizin (BNITM), Hamburg, Germany.
- Institut für Neuroimmunologie und Multiple Sklerose, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany.
| | - Johannes Brandi
- Protozoen Immunologie, Bernhard-Nocht-Institut für Tropenmedizin (BNITM), Hamburg, Germany
| | - Mathias Riehn
- Protozoen Immunologie, Bernhard-Nocht-Institut für Tropenmedizin (BNITM), Hamburg, Germany
| | - Manuel A Friese
- Institut für Neuroimmunologie und Multiple Sklerose, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | - Thomas Jacobs
- Protozoen Immunologie, Bernhard-Nocht-Institut für Tropenmedizin (BNITM), Hamburg, Germany
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9
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Howard C, Joof F, Hu R, Smith JD, Zheng Y. Probing cerebral malaria inflammation in 3D human brain microvessels. Cell Rep 2023; 42:113253. [PMID: 37819760 DOI: 10.1016/j.celrep.2023.113253] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 09/08/2023] [Accepted: 09/08/2023] [Indexed: 10/13/2023] Open
Abstract
Sequestration of Plasmodium falciparum-infected erythrocytes (IEs) in the brain microcirculation is a hallmark of cerebral malaria (CM), which leads to endothelial activation, brain swelling, and death. Here, we probed CM inflammation in a perfusable 3D human brain microvessel model. 3D brain microvessels supported in vivo-like capacities for parasite binding and maturation in situ, leading to a distinct inflammatory response from the pro-inflammatory cytokine tumor necrosis factor α (TNF-α). By combining transcriptional analysis, imaging, and leukocyte perfusion, we showed that whereas TNF-α promotes a reversible inflammatory phenotype with widespread leukocyte recruitment, parasites induce unique stress response pathways and cause localized cell adhesivity changes, focal endothelial disruptions, and apoptosis. Furthermore, parasites modified the temporal kinetics of the TNF transcriptional response, suggesting augmented inflammatory damage with the two sequential stimuli. Our findings offer mechanistic insights into CM biology in a 3D brain microvessel mimetic platform and suggest that multiple events intersect to promote brain barrier inflammation in CM.
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Affiliation(s)
- Caitlin Howard
- Department of Bioengineering, University of Washington, Seattle, WA, USA; Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 98109, USA
| | - Fatou Joof
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA 98109, USA
| | - Ruoqian Hu
- Department of Bioengineering, University of Washington, Seattle, WA, USA; Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 98109, USA
| | - Joseph D Smith
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA 98109, USA; Department of Pediatrics, School of Medicine, University of Washington, Seattle, WA, USA.
| | - Ying Zheng
- Department of Bioengineering, University of Washington, Seattle, WA, USA; Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 98109, USA.
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10
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Tewey MA, Coulibaly D, Lawton JG, Stucke EM, Zhou AE, Berry AA, Bailey JA, Pike A, Dara A, Ouattara A, Lyke KE, Ifeonu O, Laurens MB, Adams M, Takala-Harrison S, Niangaly A, Kouriba B, Koné AK, Rowe JA, Doumbo OK, Patel JJ, Tan JC, Felgner PL, Plowe CV, Thera MA, Travassos MA. Natural immunity to malaria preferentially targets the endothelial protein C receptor-binding regions of PfEMP1s. mSphere 2023; 8:e0045123. [PMID: 37791774 PMCID: PMC10597466 DOI: 10.1128/msphere.00451-23] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Accepted: 08/21/2023] [Indexed: 10/05/2023] Open
Abstract
Antibody responses to variant surface antigens (VSAs) produced by the malaria parasite Plasmodium falciparum may contribute to age-related natural immunity to severe malaria. One VSA family, P. falciparum erythrocyte membrane protein-1 (PfEMP1), includes a subset of proteins that binds endothelial protein C receptor (EPCR) in human hosts and potentially disrupts the regulation of inflammatory responses, which may lead to the development of severe malaria. We probed peptide microarrays containing segments spanning five PfEMP1 EPCR-binding domain variants with sera from 10 Malian adults and 10 children to determine the differences between adult and pediatric immune responses. We defined serorecognized peptides and amino acid residues as those that elicited a significantly higher antibody response than malaria-naïve controls. We aimed to identify regions consistently serorecognized among adults but not among children across PfEMP1 variants, potentially indicating regions that drive the development of immunity to severe malaria. Adult sera consistently demonstrated broader and more intense serologic responses to constitutive PfEMP1 peptides than pediatric sera, including peptides in EPCR-binding domains. Both adults and children serorecognized a significantly higher proportion of EPCR-binding peptides than peptides that do not directly participate in receptor binding, indicating a preferential development of serologic responses at functional residues. Over the course of a single malaria transmission season, pediatric serological responses increased between the start and the peak of the season, but waned as the transmission season ended. IMPORTANCE Severe malaria and death related to malaria disproportionately affect sub-Saharan children under 5 years of age, commonly manifesting as cerebral malaria and/or severe malarial anemia. In contrast, adults in malaria-endemic regions tend to experience asymptomatic or mild disease. Our findings indicate that natural immunity to malaria targets specific regions within the EPCR-binding domain, particularly peptides containing EPCR-binding residues. Epitopes containing these residues may be promising targets for vaccines or therapeutics directed against severe malaria. Our approach provides insight into the development of natural immunity to a binding target linked to severe malaria by characterizing an "adult-like" response as recognizing a proportion of epitopes within the PfEMP1 protein, particularly regions that mediate EPCR binding. This "adult-like" response likely requires multiple years of malaria exposure, as increases in pediatric serologic response over a single malaria transmission season do not appear significant.
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Affiliation(s)
- Madison A. Tewey
- Malaria Research Program, Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Drissa Coulibaly
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies, Bamako, Mali
| | - Jonathan G. Lawton
- Malaria Research Program, Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Emily M. Stucke
- Malaria Research Program, Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Albert E. Zhou
- Malaria Research Program, Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Andrea A. Berry
- Malaria Research Program, Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Jason A. Bailey
- Malaria Research Program, Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Andrew Pike
- Malaria Research Program, Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Antoine Dara
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies, Bamako, Mali
| | - Amed Ouattara
- Malaria Research Program, Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Kirsten E. Lyke
- Malaria Research Program, Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Olukemi Ifeonu
- Malaria Research Program, Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Matthew B. Laurens
- Malaria Research Program, Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Matthew Adams
- Malaria Research Program, Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Shannon Takala-Harrison
- Malaria Research Program, Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Amadou Niangaly
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies, Bamako, Mali
| | - Bourema Kouriba
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies, Bamako, Mali
| | - Abdoulaye K. Koné
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies, Bamako, Mali
| | - J. Alexandra Rowe
- Centre for Immunity, Infection and Evolution, Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Ogobara K. Doumbo
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies, Bamako, Mali
| | | | - John C. Tan
- Roche NimbleGen, Inc., Madison, Wisconsin, USA
| | - Philip L. Felgner
- Division of Infectious Diseases, Department of Medicine, University of California, Irvine, California, USA
| | - Christopher V. Plowe
- Malaria Research Program, Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Mahamadou A. Thera
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies, Bamako, Mali
| | - Mark A. Travassos
- Malaria Research Program, Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
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11
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Ma R, Tolia NH. Host receptor binding induces conformational changes in a PfEMP1 protein. Structure 2023; 31:1143-1144. [PMID: 37802029 PMCID: PMC11099546 DOI: 10.1016/j.str.2023.08.021] [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: 08/25/2023] [Revised: 08/28/2023] [Accepted: 08/28/2023] [Indexed: 10/08/2023]
Abstract
In this issue of Structure, Raghavan et al. present the cryo-EM structures of the malaria-associated group A PfEMP1 HB3VAR03 head in both host receptor-free and receptor-bound states. The structures are complemented by biophysical analysis and introduce an innovative model in which host-receptor binding induces conformational changes in a PfEMP1 protein.
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Affiliation(s)
- Rui Ma
- Host-Pathogen Interactions and Structural Vaccinology Section, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Niraj H Tolia
- Host-Pathogen Interactions and Structural Vaccinology Section, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA.
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12
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Rajan Raghavan SS, Turner L, Jensen RW, Johansen NT, Jensen DS, Gourdon P, Zhang J, Wang Y, Theander TG, Wang K, Lavstsen T. Endothelial protein C receptor binding induces conformational changes to severe malaria-associated group A PfEMP1. Structure 2023; 31:1174-1183.e4. [PMID: 37582356 DOI: 10.1016/j.str.2023.07.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 06/16/2023] [Accepted: 07/20/2023] [Indexed: 08/17/2023]
Abstract
Severe Plasmodium falciparum malaria infections are caused by microvascular sequestration of parasites binding to the human endothelial protein C receptor (EPCR) via the multi-domain P. falciparum erythrocyte membrane protein 1 (PfEMP1) adhesion ligands. Using cryogenic electron microscopy (Cryo-EM) and PfEMP1 sequence diversity analysis, we found that group A PfEMP1 CIDRα1 domains interact with the adjacent DBLα1 domain through central, conserved residues of the EPCR-binding site to adopt a compact conformation. Upon EPCR binding, the DBLα1 domain is displaced, and the EPCR-binding helix of CIDRα1 is turned, kinked, and twisted to reach a rearranged, stable EPCR-bound conformation. The unbound conformation and the required transition to the EPCR-bound conformation may represent a conformational masking mechanism of immune evasion for the PfEMP1 family.
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Affiliation(s)
- Sai Sundar Rajan Raghavan
- Centre for Medical Parasitology, Department of Immunology and Microbiology, University of Copenhagen, and Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark
| | - Louise Turner
- Centre for Medical Parasitology, Department of Immunology and Microbiology, University of Copenhagen, and Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark
| | - Rasmus W Jensen
- Centre for Medical Parasitology, Department of Immunology and Microbiology, University of Copenhagen, and Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark
| | - Nicolai Tidemand Johansen
- Section for Transport Biology, Department of Plant and Environmental Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Daniel Skjold Jensen
- Centre for Medical Parasitology, Department of Immunology and Microbiology, University of Copenhagen, and Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark
| | - Pontus Gourdon
- Department of Experimental Medical Science, Lund University, Lund, Sweden; Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jinqiu Zhang
- The Provincial International Science and Technology Cooperation Base on Engineering Biology, International Campus of Zhejiang University, Haining, China
| | - Yong Wang
- The Provincial International Science and Technology Cooperation Base on Engineering Biology, International Campus of Zhejiang University, Haining, China
| | - Thor Grundtvig Theander
- Centre for Medical Parasitology, Department of Immunology and Microbiology, University of Copenhagen, and Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark
| | - Kaituo Wang
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark.
| | - Thomas Lavstsen
- Centre for Medical Parasitology, Department of Immunology and Microbiology, University of Copenhagen, and Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark.
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13
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Gill J, Sharma A. Structural and genomic analysis of single nucleotide polymorphisms in human host factor endothelial protein C receptor (EPCR) reveals complex interplay with malaria parasites. INFECTION, GENETICS AND EVOLUTION : JOURNAL OF MOLECULAR EPIDEMIOLOGY AND EVOLUTIONARY GENETICS IN INFECTIOUS DISEASES 2023; 110:105413. [PMID: 36775045 DOI: 10.1016/j.meegid.2023.105413] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 01/12/2023] [Accepted: 02/08/2023] [Indexed: 02/12/2023]
Abstract
Plasmodium parasites responsible for malaria follow a complex life cycle of which half takes place inside the human host. Parasites present diverse antigens at different stages of their life cycle and interact with many surface molecules to attach to and enter host cells. The CIDRα1 domain of Plasmodium falciparum Erythrocyte Membrane Protein 1 (PfEMP1) in infected erythrocytes adheres to one such vascular receptor endothelial protein C receptor (EPCR). EPCR is implicated in the pathogenesis of severe malaria as preferential binding of CIDRα1 to endothelium results in widespread sequestration of infected erythrocytes leading to endothelium inflammation and severe disease. A single EPCR variant S219G is clinically reported to provide protection from severe malaria. In this work, we have collated all single nucleotide polymorphisms (SNPs) in EPCR from dbSNP. We structurally mapped the SNPs on the three-dimensional complex of EPCR and PfEMP1 CIDRα1. Analysis shows that most EPCR mutations lie on the receptor surface and are non-conservative. Of the 11 mutations in the CIDRα1-interaction region of EPCR, S88P, L96V/I, and R98L/H/P/C are seen with comparably higher occurrences in diverse populations. Our structural analysis details a framework of the interactions between the parasite ligand and host factor EPCR. These structural glimpses provide a blueprint for designing both field-based variant sequencing studies and vaccine development.
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Affiliation(s)
- Jasmita Gill
- ICMR-National Institute of Malaria Research, New Delhi, India.
| | - Amit Sharma
- ICMR-National Institute of Malaria Research, New Delhi, India; International Centre for Genetic Engineering and Biotechnology, New Delhi, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India.
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14
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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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15
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Silva-Becerril A, Quintero-Martínez A, Hernández-Santoyo A. Structural and functional analysis of a tandem repeat galacturonic acid-binding lectin from the sea hare Aplysia californica. FISH & SHELLFISH IMMUNOLOGY 2023; 132:108513. [PMID: 36584757 DOI: 10.1016/j.fsi.2022.108513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 12/10/2022] [Accepted: 12/27/2022] [Indexed: 06/17/2023]
Abstract
A d-galacturonic acid-specific lectin, named AcL, was purified from the sea hare Aplysia californica by galactose-agarose affinity chromatography. AcL has a molecular mass of 27.5 kDa determined by MALDI-TOF mass spectrometry. This lectin shows a good affinity for d-galacturonic acid and a lower affinity for galactosides: raffinose, melibiose, α and β-lactose, and d-galactose. We determined the amino acid sequence of AcL by trypsin digestion and subsequent peptide analysis by mass spectrometry, resulting in a 238 amino acid protein with a theoretical molecular mass of 26.4 kDa. The difference between the theoretical and experimental values can be attributed to post-translational modifications. Thiol-disulfide quantification discerned five disulfide bonds and three free cysteines. The structure of Acl is mainly comprised of beta sheets, determined by circular dichroism, and predicted with AlphaFold. Theoretical models depict three nearly identical tandem domains consisting of two beta sheets each. From docking analysis, we identified AcL glycan-binding sites as multiple conserved motifs in each domain. Furthermore, phylogenetic analysis based on its structure and sequence showed that AcL and its closest homologues (GalULs) form a clear monophyletic group, distinct from other glycan-binding proteins with a jelly-roll fold: lectins of types F and H. GalULs possess four conserved sequence regions that distinguish them and are either ligand-binding motifs or stabilizing network hubs. We suggest that this new family should be referred to as GalUL or D-type, following the traditional naming of lectins; D standing for depilans, the epithet for the species (Aplysia depilans) from which a lectin of this family was first isolated and described.
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Affiliation(s)
- Areli Silva-Becerril
- Instituto de Química, Universidad Nacional Autónoma de México, Coyoacán, Ciudad de México, 04510, Mexico
| | - Adrián Quintero-Martínez
- Instituto de Química, Universidad Nacional Autónoma de México, Coyoacán, Ciudad de México, 04510, Mexico
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16
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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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17
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Ruybal-Pesántez S, Tiedje KE, Pilosof S, Tonkin-Hill G, He Q, Rask TS, Amenga-Etego L, Oduro AR, Koram KA, Pascual M, Day KP. Age-specific patterns of DBLα var diversity can explain why residents of high malaria transmission areas remain susceptible to Plasmodium falciparum blood stage infection throughout life. Int J Parasitol 2022; 52:721-731. [PMID: 35093396 PMCID: PMC9339046 DOI: 10.1016/j.ijpara.2021.12.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 11/29/2021] [Accepted: 12/01/2021] [Indexed: 12/26/2022]
Abstract
Immunity to Plasmodium falciparum is non-sterilising, thus individuals residing in malaria-endemic areas are at risk of infection throughout their lifetime. Here we seek to find a genomic epidemiological explanation for why residents of all ages harbour blood stage infections despite lifelong exposure to P. falciparum in areas of high transmission. We do this by exploring, for the first known time, the age-specific patterns of diversity of variant antigen encoding (var) genes in the reservoir of infection. Microscopic and submicroscopic P. falciparum infections were analysed at the end of the wet and dry seasons in 2012-2013 for a cohort of 1541 residents aged from 1 to 91 years in an area characterised by high seasonal malaria transmission in Ghana. By sequencing the near ubiquitous Duffy-binding-like alpha domain (DBLα) that encodes immunogenic domains, we defined var gene diversity in an estimated 1096 genomes detected in sequential wet and dry season sampling of this cohort. Unprecedented var (DBLα) diversity was observed in all ages with 42,399 unique var types detected. There was a high degree of maintenance of types between seasons (>40% seen more than once), with many of the same types, especially upsA, appearing multiple times in isolates from different individuals. Children and adolescents were found to be significant reservoirs of var DBLα diversity compared with adults. Var repertoires within individuals were highly variable, with children having more related var repertoires compared to adolescents and adults. Individuals of all ages harboured multiple genomes with var repertoires unrelated to those infecting other hosts. High turnover of parasites with diverse isolate var repertoires was also observed in all ages. These age-specific patterns are best explained by variant-specific immune selection. The observed level of var diversity for the population was then used to simulate the development of variant-specific immunity to the diverse var types under conservative assumptions. Simulations showed that the extent of observed var diversity with limited repertoire relatedness was sufficient to explain why adolescents and adults in this community remain susceptible to blood stage infection, even with multiple genomes.
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Affiliation(s)
| | - Kathryn E. Tiedje
- School of BioSciences, Bio21 Institute, The University of Melbourne, Australia,Department of Microbiology and Immunology, Bio21 Institute and Peter Doherty Institute, The University of Melbourne, Australia
| | - Shai Pilosof
- Department of Ecology and Evolution, University of Chicago, USA,Department of Life Sciences, Ben-Gurion University, Be’er-Sheva, Israel
| | - Gerry Tonkin-Hill
- School of BioSciences, Bio21 Institute, The University of Melbourne, Australia,Bioinformatics Division, Walter and Eliza Hall Institute of Medial Research, Australia
| | - Qixin He
- Department of Ecology and Evolution, University of Chicago, USA
| | - Thomas S. Rask
- School of BioSciences, Bio21 Institute, The University of Melbourne, Australia
| | - Lucas Amenga-Etego
- West African Centre for Cell Biology and Infectious Pathogens, Department of Biochemistry, Cell and Molecular Biology, University of Ghana, Ghana,Navrongo Health Research Centre, Ghana Health Service, Ghana
| | | | - Kwadwo A. Koram
- Epidemiology Department, Noguchi Memorial Institute for Medical Research, University of Ghana, Ghana
| | | | - Karen P. Day
- School of BioSciences, Bio21 Institute, The University of Melbourne, Australia,Department of Microbiology and Immunology, Bio21 Institute and Peter Doherty Institute, The University of Melbourne, Australia,Corresponding author. (K.P. Day)
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18
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Erausquin E, Morán-Garrido M, Sáiz J, Barbas C, Dichiara-Rodríguez G, Urdiciain A, López-Sagaseta J. Identification of a broad lipid repertoire associated to the endothelial cell protein C receptor (EPCR). Sci Rep 2022; 12:15127. [PMID: 36068249 PMCID: PMC9448719 DOI: 10.1038/s41598-022-18844-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Accepted: 08/22/2022] [Indexed: 11/09/2022] Open
Abstract
Evidence is mounting that the nature of the lipid bound to the endothelial cell protein C receptor (EPCR) has an impact on its biological roles, as observed in anticoagulation and more recently, in autoimmune disease. Phosphatidylethanolamine and phosphatidylcholine species dominate the EPCR lipid cargo, yet, the extent of diversity in the EPCR-associated lipid repertoire is still unknown and remains to be uncovered. We undertook mass spectrometry analyses to decipher the EPCR lipidome, and identified species not yet described as EPCR ligands, such as phosphatidylinositols and phosphatidylserines. Remarkably, we found further, more structurally divergent lipids classes, represented by ceramides and sphingomyelins, both in less abundant quantities. In support of our mass spectrometry results and previous studies, high-resolution crystal structures of EPCR in three different space groups point to a prevalent diacyl phospholipid moiety in EPCR’s pocket but a mobile and ambiguous lipid polar head group. In sum, these studies indicate that EPCR can associate with varied lipid classes, which might impact its properties in anticoagulation and the onset of autoimmune disease.
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Affiliation(s)
- Elena Erausquin
- Unit of Protein Crystallography and Structural Immunology, Navarrabiomed, 31008, Pamplona, Navarra, Spain.,Public University of Navarra (UPNA), 31008, Pamplona, Navarra, Spain.,Navarra University Hospital, 31008, Pamplona, Navarra, Spain
| | - María Morán-Garrido
- Centre of Metabolomics and Bioanalysis (CEMBIO), Department of Chemistry and Biochemistry, School of Pharmacy, Universidad San Pablo-CEU, CEU Universities, Urbanización Montepríncipe, 28660, Boadilla del Monte, Spain
| | - Jorge Sáiz
- Centre of Metabolomics and Bioanalysis (CEMBIO), Department of Chemistry and Biochemistry, School of Pharmacy, Universidad San Pablo-CEU, CEU Universities, Urbanización Montepríncipe, 28660, Boadilla del Monte, Spain
| | - Coral Barbas
- Centre of Metabolomics and Bioanalysis (CEMBIO), Department of Chemistry and Biochemistry, School of Pharmacy, Universidad San Pablo-CEU, CEU Universities, Urbanización Montepríncipe, 28660, Boadilla del Monte, Spain
| | - Gilda Dichiara-Rodríguez
- Unit of Protein Crystallography and Structural Immunology, Navarrabiomed, 31008, Pamplona, Navarra, Spain.,Public University of Navarra (UPNA), 31008, Pamplona, Navarra, Spain.,Navarra University Hospital, 31008, Pamplona, Navarra, Spain
| | - Alejandro Urdiciain
- Unit of Protein Crystallography and Structural Immunology, Navarrabiomed, 31008, Pamplona, Navarra, Spain.,Public University of Navarra (UPNA), 31008, Pamplona, Navarra, Spain.,Navarra University Hospital, 31008, Pamplona, Navarra, Spain
| | - Jacinto López-Sagaseta
- Unit of Protein Crystallography and Structural Immunology, Navarrabiomed, 31008, Pamplona, Navarra, Spain. .,Public University of Navarra (UPNA), 31008, Pamplona, Navarra, Spain. .,Navarra University Hospital, 31008, Pamplona, Navarra, Spain.
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19
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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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20
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Takashima E, Kanoi BN, Nagaoka H, Morita M, Hassan I, Palacpac NMQ, Egwang TG, Horii T, Gitaka J, Tsuboi T. Meta-Analysis of Human Antibodies Against Plasmodium falciparum Variable Surface and Merozoite Stage Antigens. Front Immunol 2022; 13:887219. [PMID: 35757771 PMCID: PMC9218060 DOI: 10.3389/fimmu.2022.887219] [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: 03/01/2022] [Accepted: 05/11/2022] [Indexed: 11/30/2022] Open
Abstract
Concerted efforts to fight malaria have caused significant reductions in global malaria cases and mortality. Sustaining this will be critical to avoid rebound and outbreaks of seasonal malaria. Identifying predictive attributes that define clinical malaria will be key to guide development of second-generation tools to fight malaria. Broadly reactive antibodies against variable surface antigens that are expressed on the surface of infected erythrocytes and merozoites stage antigens are targets of naturally acquired immunity and prime candidates for anti-malaria therapeutics and vaccines. However, predicting the relationship between the antigen-specific antibodies and protection from clinical malaria remains unresolved. Here, we used new datasets and multiple approaches combined with re-analysis of our previous data to assess the multi-dimensional and complex relationship between antibody responses and clinical malaria outcomes. We observed 22 antigens (17 PfEMP1 domains, 3 RIFIN family members, merozoite surface protein 3 (PF3D7_1035400), and merozoites-associated armadillo repeats protein (PF3D7_1035900) that were selected across three different clinical malaria definitions (1,000/2,500/5,000 parasites/µl plus fever). In addition, Principal Components Analysis (PCA) indicated that the first three components (Dim1, Dim2 and Dim3 with eigenvalues of 306, 48, and 29, respectively) accounted for 66.1% of the total variations seen. Specifically, the Dim1, Dim2 and Dim3 explained 52.8%, 8.2% and 5% of variability, respectively. We further observed a significant relationship between the first component scores and age with antibodies to PfEMP1 domains being the key contributing variables. This is consistent with a recent proposal suggesting that there is an ordered acquisition of antibodies targeting PfEMP1 proteins. Thus, although limited, and further work on the significance of the selected antigens will be required, these approaches may provide insights for identification of drivers of naturally acquired protective immunity as well as guide development of additional tools for malaria elimination and eradication.
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Affiliation(s)
- Eizo Takashima
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Japan
| | - Bernard N Kanoi
- Centre for Research in Infectious Diseases, Directorate of Research and Innovation, Mount Kenya University, Thika, Kenya
| | - Hikaru Nagaoka
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Japan
| | - Masayuki Morita
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Japan
| | - Ifra Hassan
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Japan
| | - Nirianne M Q Palacpac
- Department of Malaria Vaccine Development, Research Institute for Microbial Diseases, Osaka University, Suita, Japan
| | | | - Toshihiro Horii
- Department of Malaria Vaccine Development, Research Institute for Microbial Diseases, Osaka University, Suita, Japan
| | - Jesse Gitaka
- Centre for Research in Infectious Diseases, Directorate of Research and Innovation, Mount Kenya University, Thika, Kenya
| | - Takafumi Tsuboi
- Division of Cell-Free Sciences, Proteo-Science Center, Ehime University, Matsuyama, Japan
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21
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Albrecht-Schgoer K, Lackner P, Schmutzhard E, Baier G. Cerebral Malaria: Current Clinical and Immunological Aspects. Front Immunol 2022; 13:863568. [PMID: 35514965 PMCID: PMC9067128 DOI: 10.3389/fimmu.2022.863568] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 03/21/2022] [Indexed: 11/23/2022] Open
Abstract
This review focuses on current clinical and immunological aspects of cerebral malaria induced by Plasmodium falciparum infection. Albeit many issues concerning the inflammatory responses remain unresolved and need further investigations, current knowledge of the underlying molecular mechanisms is highlighted. Furthermore, and in the light of significant limitations in preventative diagnosis and treatment of cerebral malaria, this review mainly discusses our understanding of immune mechanisms in the light of the most recent research findings. Remarkably, the newly proposed CD8+ T cell-driven pathophysiological aspects within the central nervous system are summarized, giving first rational insights into encouraging studies with immune-modulating adjunctive therapies that protect from symptomatic cerebral participation of Plasmodium falciparum infection.
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Affiliation(s)
- Karin Albrecht-Schgoer
- Division of Translational Cell Genetics, Medical University of Innsbruck, Innsbruck, Austria
| | - Peter Lackner
- Department of Neurology, Klinik Floridsdorf, Wien, Austria
| | - Erich Schmutzhard
- Department of Neurology, Medical University of Innsbruck, Innsbruck, Austria
| | - Gottfried Baier
- Division of Translational Cell Genetics, Medical University of Innsbruck, Innsbruck, Austria
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22
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Coker JA, Katis VL, Fairhead M, Schwenzer A, Clemmensen SB, Frandsen BU, de Jongh WA, Gileadi O, Burgess-Brown NA, Marsden BD, Midwood KS, Yue WW. FAS2FURIOUS: Moderate-Throughput Secreted Expression of Difficult Recombinant Proteins in Drosophila S2 Cells. Front Bioeng Biotechnol 2022; 10:871933. [PMID: 35600892 PMCID: PMC9117644 DOI: 10.3389/fbioe.2022.871933] [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: 02/09/2022] [Accepted: 04/04/2022] [Indexed: 11/23/2022] Open
Abstract
Recombinant protein expression in eukaryotic insect cells is a powerful approach for producing challenging targets. However, due to incompatibility with standard baculoviral platforms and existing low-throughput methodology, the use of the Drosophila melanogaster “S2” cell line lags behind more common insect cell lines such as Sf9 or High-Five™. Due to the advantages of S2 cells, particularly for secreted and secretable proteins, the lack of a simple and parallelizable S2-based platform represents a bottleneck, particularly for biochemical and biophysical laboratories. Therefore, we developed FAS2FURIOUS, a simple and rapid S2 expression pipeline built upon an existing low-throughput commercial platform. FAS2FURIOUS is comparable in effort to simple E. coli systems and allows users to clone and test up to 46 constructs in just 2 weeks. Given the ability of S2 cells to express challenging targets, including receptor ectodomains, secreted glycoproteins, and viral antigens, FAS2FURIOUS represents an attractive orthogonal approach for protein expression in eukaryotic cells.
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Affiliation(s)
- Jesse A. Coker
- Centre for Medicines Discovery, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Kennedy Institute of Rheumatology, University of Oxford, Oxford, United Kingdom
| | - Vittorio L. Katis
- Centre for Medicines Discovery, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Michael Fairhead
- Centre for Medicines Discovery, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Anja Schwenzer
- Kennedy Institute of Rheumatology, University of Oxford, Oxford, United Kingdom
| | | | - Bent U. Frandsen
- ExpreSion Biotechnologies, SCION-DTU Science Park, Hørsholm, Denmark
| | | | - Opher Gileadi
- Centre for Medicines Discovery, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Nicola A. Burgess-Brown
- Centre for Medicines Discovery, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Brian D. Marsden
- Centre for Medicines Discovery, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Kennedy Institute of Rheumatology, University of Oxford, Oxford, United Kingdom
| | - Kim S. Midwood
- Kennedy Institute of Rheumatology, University of Oxford, Oxford, United Kingdom
| | - Wyatt W. Yue
- Centre for Medicines Discovery, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- *Correspondence: Wyatt W. Yue,
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23
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Rosa-Gonçalves P, Ribeiro-Gomes FL, Daniel-Ribeiro CT. Malaria Related Neurocognitive Deficits and Behavioral Alterations. Front Cell Infect Microbiol 2022; 12:829413. [PMID: 35281436 PMCID: PMC8904205 DOI: 10.3389/fcimb.2022.829413] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2021] [Accepted: 01/31/2022] [Indexed: 01/29/2023] Open
Abstract
Typical of tropical and subtropical regions, malaria is caused by protozoa of the genus Plasmodium and is, still today, despite all efforts and advances in controlling the disease, a major issue of public health. Its clinical course can present either as the classic episodes of fever, sweating, chills and headache or as nonspecific symptoms of acute febrile syndromes and may evolve to severe forms. Survivors of cerebral malaria, the most severe and lethal complication of the disease, might develop neurological, cognitive and behavioral sequelae. This overview discusses the neurocognitive deficits and behavioral alterations resulting from human naturally acquired infections and murine experimental models of malaria. We highlighted recent reports of cognitive and behavioral sequelae of non-severe malaria, the most prevalent clinical form of the disease worldwide. These sequelae have gained more attention in recent years and therapies for them are required and demand advances in the understanding of neuropathogenesis. Recent studies using experimental murine models point to immunomodulation as a potential approach to prevent or revert neurocognitive sequelae of malaria.
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Affiliation(s)
- Pamela Rosa-Gonçalves
- Laboratório de Pesquisa em Malária, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz (Fiocruz), Rio de Janeiro, Brazil
- Centro de Pesquisa, Diagnóstico e Treinamento em Malária, Fiocruz and Secretaria de Vigilância em Saúde, Ministério da Saúde, Rio de Janeiro, Brazil
- Laboratório de Biologia, campus Duque de Caxias, Colégio Pedro II, Duque de Caxias, Brazil
- *Correspondence: Pamela Rosa-Gonçalves,
| | - Flávia Lima Ribeiro-Gomes
- Laboratório de Pesquisa em Malária, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz (Fiocruz), Rio de Janeiro, Brazil
- Centro de Pesquisa, Diagnóstico e Treinamento em Malária, Fiocruz and Secretaria de Vigilância em Saúde, Ministério da Saúde, Rio de Janeiro, Brazil
| | - Cláudio Tadeu Daniel-Ribeiro
- Laboratório de Pesquisa em Malária, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz (Fiocruz), Rio de Janeiro, Brazil
- Centro de Pesquisa, Diagnóstico e Treinamento em Malária, Fiocruz and Secretaria de Vigilância em Saúde, Ministério da Saúde, Rio de Janeiro, Brazil
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24
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Ortolan LS, Avril M, Xue J, Seydel KB, Zheng Y, Smith JD. Plasmodium falciparum Parasite Lines Expressing DC8 and Group A PfEMP1 Bind to Brain, Intestinal, and Kidney Endothelial Cells. Front Cell Infect Microbiol 2022; 12:813011. [PMID: 35155278 PMCID: PMC8831842 DOI: 10.3389/fcimb.2022.813011] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 01/10/2022] [Indexed: 11/13/2022] Open
Abstract
Cytoadhesion of Plasmodium falciparum-infected red blood cells is a virulence determinant associated with microvascular obstruction and organ complications. The gastrointestinal tract is a major site of sequestration in fatal cerebral malaria cases and kidney complications are common in severe malaria, but parasite interactions with these microvascular sites are poorly characterized. To study parasite tropism for different microvascular sites, we investigated binding of parasite lines to primary human microvascular endothelial cells from intestine (HIMEC) and peritubular kidney (HKMEC) sites. Of the three major host receptors for P. falciparum, CD36 had low or negligible expression; endothelial protein C receptor (EPCR) had the broadest constitutive expression; and intercellular adhesion molecule 1 (ICAM-1) was weakly expressed on resting cells and was strongly upregulated by TNF-α on primary endothelial cells from the brain, intestine, and peritubular kidney sites. By studying parasite lines expressing var genes linked to severe malaria, we provide evidence that both the DC8 and Group A EPCR-binding subsets of the P. falciparum erythrocyte membrane protein 1 (PfEMP1) family encodes binding affinity for brain, intestinal, and peritubular kidney endothelial cells, and that DC8 parasite adhesion was partially dependent on EPCR. Collectively, these findings raise the possibility of a brain-gut-kidney binding axis contributing to multi-organ complications in severe malaria.
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Affiliation(s)
- Luana S. Ortolan
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, WA, United States
| | - Marion Avril
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, WA, United States
| | - Jun Xue
- Department of Bioengineering, University of Washington, Seattle, WA, United States
| | - Karl B. Seydel
- Department of Osteopathic Medical Specialties, College of Osteopathic Medicine, Michigan State University, East Lansing, MI, United States
- Blantyre Malaria Project, Kamuzu University of Health Sciences, Blantyre, Malawi
| | - Ying Zheng
- Department of Bioengineering, University of Washington, Seattle, WA, United States
| | - Joseph D. Smith
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, WA, United States
- Department of Pediatrics, University of Washington, Seattle, WA, United States
- *Correspondence: Joseph D. Smith,
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25
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Indari O, Sk MF, Jakhmola S, Jonniya NA, Jha HC, Kar P. Decoding the Host-Parasite Protein Interactions Involved in Cerebral Malaria Through Glares of Molecular Dynamics Simulations. J Phys Chem B 2022; 126:387-402. [PMID: 34989590 DOI: 10.1021/acs.jpcb.1c07850] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Malaria causes millions of deaths every year. The malaria parasite spends a substantial part of its life cycle inside human erythrocytes. Inside erythrocytes, it synthesizes and displays various proteins onto the erythrocyte surface, such as Plasmodium falciparum erythrocytic membrane protein-1 (PfEMP1). This protein contains cysteine-rich interdomain region (CIDR) domains which have many subtypes based on sequence diversity and can cross-talk with host molecules. The CIDRα1.4 subtype can attach host endothelial protein C receptor (EPCR). This interaction facilitates infected erythrocyte adherence to brain endothelium and subsequent development of cerebral malaria. Through molecular dynamics simulations in conjunction with the molecular mechanics Poisson-Boltzmann surface area (MM/PBSA) method, we explored the mechanism of interaction in the CIDRα1-EPCR complex. We examined the structural behavior of two CIDRα1 molecules (encoded by HB3-isolate var03-gene and IT4-isolate var07-gene) with EPCR unbound and bound (complex) forms. HB3var03CIDRα1 in apo and complexed with EPCR was comparatively more stable than IT4var07CIDRα1. Both of the complexes adopted two distinct conformational energy states. The hydrophobic residues played a crucial role in the binding of both complexes. For HB3var03CIDRα1-EPCR, the dominant energetic components were total polar interactions, while in IT4var07CIDRα1-EPCR, the primary interaction was van der Waals and nonpolar solvation energy. The study also revealed details such as correlated conformational motions and secondary structure evolution. Further, it elucidated various hotspot residues involved in protein-protein recognition. Overall, our study provides additional information on the structural behavior of CIDR molecules in unbound and receptor-bound states, which will help to design potent inhibitors.
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Affiliation(s)
- Omkar Indari
- Department of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, Khandwa Road, Indore, MP 453552, India
| | - Md Fulbabu Sk
- Department of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, Khandwa Road, Indore, MP 453552, India
| | - Shweta Jakhmola
- Department of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, Khandwa Road, Indore, MP 453552, India
| | - Nisha Amarnath Jonniya
- Department of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, Khandwa Road, Indore, MP 453552, India
| | - Hem Chandra Jha
- Department of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, Khandwa Road, Indore, MP 453552, India
| | - Parimal Kar
- Department of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, Khandwa Road, Indore, MP 453552, India
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26
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Andisi KC, Abdi AI. Analysis of var Gene Transcription Pattern Using DBLα Tags. Methods Mol Biol 2022; 2470:173-184. [PMID: 35881346 PMCID: PMC7613572 DOI: 10.1007/978-1-0716-2189-9_14] [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] [Indexed: 10/26/2022]
Abstract
AbstractThe Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) antigens, which are encoded by a multigene family called var genes, are exported and inserted onto the surface of the infected erythrocytes. PfEMP1 plays a key role in the pathogenesis of severe malaria and are major targets of naturally acquired immunity. Studying the expression pattern of var genes in P. falciparum clinical isolates is crucial for understanding disease mechanism and immunity to malaria. However, var genes are highly variable, which makes it difficult to study their expression in clinical isolates obtained directly from malaria patients. In this chapter, we describe an approach for analysis of var gene expression that targets a region referred to as DBLα tag, which is relatively conserved in all var genes.
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27
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Olsen RW, Suurbaar J, Jensen AR. Receptor Affinity-Based Purification of PfEMP1 Proteins. Methods Mol Biol 2022; 2470:299-308. [PMID: 35881354 DOI: 10.1007/978-1-0716-2189-9_22] [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] [Indexed: 06/15/2023]
Abstract
The virulence of Plasmodium falciparum is linked to the ability of infected erythrocytes (IEs) to bind a range of human receptors. This binding is mediated by a family of highly polymorphic proteins known as P. falciparum erythrocyte membrane protein 1 (PfEMP1). PfEMP1 proteins are expressed on the surface of IEs and are composed of extracellular domains (NTS, CIDR, DBL), a transmembrane region and an acidic C-terminal segment. Subdomains of the extracellular N-terminal part of PfEMP1 molecules have been shown to bind specific receptors.In this chapter, we describe how to purify PfEMP1 proteins by a receptor affinity-based method. This includes how to prepare affinity columns and how to subsequently test the functionality of the purified PfEMP1 protein in an ELISA-based assay.
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Affiliation(s)
- Rebecca W Olsen
- Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, Centre for Medical Parasitology, University of Copenhagen, Copenhagen, Denmark.
| | - Jennifer Suurbaar
- Department of Immunology, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
- Department of Biochemistry, Cell and Molecular Biology, West Africa Centre for Cell Biology of Infectious Pathogens, University of Ghana, Accra, Ghana
| | - Anja Ramstedt Jensen
- Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, Centre for Medical Parasitology, University of Copenhagen, Copenhagen, Denmark
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28
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Olsen RW, Suurbaar J, Jensen AR. Affinity Purification of PfEMP1-Specific Antibodies from Human Blood. Methods Mol Biol 2022; 2470:369-379. [PMID: 35881359 DOI: 10.1007/978-1-0716-2189-9_27] [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] [Indexed: 06/15/2023]
Abstract
Acquired immunity against Plasmodium falciparum infections relies heavily on IgG antibodies specific for PfEMP1 proteins expressed on the surface of infected erythrocytes. Purified human antibodies can be used, for example, to study the interactions between specific PfEMP1 proteins and receptors expressed by human endothelial cells, and to identify which IgG antibodies play a functional role in natural acquired immunity.This chapter describe how to affinity purify PfEMP1-specific human antibodies on an affinity column coupled with PfEMP1 protein. We include ELISA-based methods for identification of human plasma samples reactive against PfEMP1, and for testing of affinity purified IgG antibodies prior to their use in more advanced procedures.
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Affiliation(s)
- Rebecca W Olsen
- Centre for Medical Parasitology, Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
| | - Jennifer Suurbaar
- Centre for Medical Parasitology, Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Immunology, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
- West Africa Centre for Cell Biology of Infectious Pathogens, Department of Biochemistry, Cell and Molecular Biology, University of Ghana, Accra, Ghana
| | - Anja Ramstedt Jensen
- Centre for Medical Parasitology, Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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29
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Olsen RW, Suurbaar J, Jensen AR. Analysis of Antibody Inhibition of PfEMP1 Binding by Competition ELISA. Methods Mol Biol 2022; 2470:485-491. [PMID: 35881368 DOI: 10.1007/978-1-0716-2189-9_36] [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] [Indexed: 06/15/2023]
Abstract
Plasmodium falciparum express variant antigens on the surface of infected erythrocytes (IEs). These include proteins of the P. falciparum erythrocyte membrane protein 1 (PfEMP1) family. PfEMP1 proteins mediate binding of IEs to various human endothelial receptors and induce antibodies response during natural infections. In this chapter, we describe a competition ELISA that is an assay for antibodies neutralizing binding of PfEMP1 proteins to their cognate receptor.
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Affiliation(s)
- Rebecca W Olsen
- Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, Centre for Medical Parasitology, University of Copenhagen, Copenhagen, Denmark.
| | - Jennifer Suurbaar
- Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, Centre for Medical Parasitology, University of Copenhagen, Copenhagen, Denmark
- Department of Immunology, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
- Department of Biochemistry, Cell and Molecular Biology, West Africa Centre for Cell Biology of Infectious Pathogens, University of Ghana, Accra, Ghana
| | - Anja Ramstedt Jensen
- Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, Centre for Medical Parasitology, University of Copenhagen, Copenhagen, Denmark
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30
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Lennartz F, Higgins MK. Surface Plasmon Resonance Analysis of PfEMP1 Interaction with Receptors. Methods Mol Biol 2022; 2470:467-482. [PMID: 35881367 DOI: 10.1007/978-1-0716-2189-9_35] [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] [Indexed: 06/15/2023]
Abstract
A detailed understanding of the interaction between the highly variant Plasmodium falciparum erythrocyte membrane proteins 1 (PfEMP1) and their human binding partners is essential to explain their roles in disease development in malaria, as well as to understand how antibodies can inhibit these interactions and how the parasite manages to evade such an immune response. This chapter focuses on using surface plasmon resonance (SPR) as a reproducible, high-throughput method to quantitatively characterize these interactions. We describe how to utilize protein A or A/G and streptavidin for protein immobilization on SPR sensor chips and provide instructions on how to biotinylate proteins for this purpose and how to use SPR for binding competition assays. Since these experiments rely on recombinant proteins, we also present a method to verify their structural integrity using circular dichroism spectroscopy.
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Affiliation(s)
- Frank Lennartz
- Department of Biochemistry, University of Oxford, Oxford, UK.
- Helmholtz-Zentrum Berlin für Materialien und Energie, Macromolecular Crystallography, Berlin, Germany.
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31
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Andoh NE, Gyan BA. The Potential Roles of Glial Cells in the Neuropathogenesis of Cerebral Malaria. Front Cell Infect Microbiol 2021; 11:741370. [PMID: 34692564 PMCID: PMC8529055 DOI: 10.3389/fcimb.2021.741370] [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] [Received: 07/14/2021] [Accepted: 09/17/2021] [Indexed: 01/02/2023] Open
Abstract
Cerebral malaria (CM) is a severe neurological complication of malaria caused by the Plasmodium falciparum parasite. It is one of the leading causes of death in children under 5 years of age in Sub-Saharan Africa. CM is associated with blood-brain barrier disruption and long-term neurological sequelae in survivors of CM. Despite the vast amount of research on cerebral malaria, the cause of neurological sequelae observed in CM patients is poorly understood. In this article, the potential roles of glial cells, astrocytes, and microglia, in cerebral malaria pathogenesis are reviewed. The possible mechanisms by which glial cells contribute to neurological damage in CM patients are also examined.
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Affiliation(s)
- Nana Efua Andoh
- Noguchi Memorial Institute for Medical Research, Department of Parasitology, University of Ghana, Accra, Ghana
| | - Ben Adu Gyan
- Noguchi Memorial Institute for Medical Research, Department of Immunology, University of Ghana, Accra, Ghana
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32
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Targeting the CD146/Galectin-9 axis protects the integrity of the blood-brain barrier in experimental cerebral malaria. Cell Mol Immunol 2021; 18:2443-2454. [PMID: 33203936 PMCID: PMC8484550 DOI: 10.1038/s41423-020-00582-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 10/21/2020] [Indexed: 02/07/2023] Open
Abstract
Cerebral malaria (CM) is a life-threatening diffuse encephalopathy caused by Plasmodium falciparum, in which the destruction of the blood-brain barrier (BBB) is the main cause of death. However, increasing evidence has shown that antimalarial drugs, the current treatment for CM, do little to protect against CM-induced BBB damage. Therefore, a means to alleviate BBB dysfunction would be a promising adjuvant therapy for CM. The adhesion molecule CD146 has been reported to be expressed in both endothelial cells and proinflammatory immune cells and mediates neuroinflammation. Here, we demonstrate that CD146 expressed on BBB endothelial cells but not immune cells is a novel therapeutic target in a mouse model of experimental cerebral malaria (eCM). Endothelial CD146 is upregulated during eCM development and facilitates the sequestration of infected red blood cells (RBCs) and/or proinflammatory lymphocytes in CNS blood vessels, thereby promoting the disruption of BBB integrity. Mechanistic studies showed that the interaction of CD146 and Galectin-9 contributes to the aggregation of infected RBCs and lymphocytes. Deletion of endothelial CD146 or treatment with the anti-CD146 antibody AA98 prevents severe signs of eCM, such as limb paralysis, brain vascular leakage, and death. In addition, AA98 combined with the antiparasitic drug artemether improved the cognition and memory of mice with eCM. Taken together, our findings suggest that endothelial CD146 is a novel and promising target in combination with antiparasitic drugs for future CM therapies.
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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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Higgins MK. Why it might be bad for brain cells to eat malaria parasites. J Exp Med 2021; 218:211746. [PMID: 33528504 PMCID: PMC7856916 DOI: 10.1084/jem.20202664] [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] [Indexed: 11/05/2022] Open
Abstract
In this issue, Adams et al. (2021. J. Exp. Med. https://doi.org/10.1084/jem.20201266) show that red blood cells infected with strains of Plasmodium falciparum, which are commonly found in cerebral malaria patients, are specifically internalized by brain endothelial cells, perhaps contributing to the symptoms of the disease.
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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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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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Azasi Y, Low LM, Just AN, Raghavan SSR, Wang CW, Valenzuela-Leon P, Rowe JA, Smith JD, Lavstsen T, Turner L, Calvo E, Miller LH. Complement C1s cleaves PfEMP1 at interdomain conserved sites inhibiting Plasmodium falciparum cytoadherence. Proc Natl Acad Sci U S A 2021; 118:e2104166118. [PMID: 34035177 PMCID: PMC8179237 DOI: 10.1073/pnas.2104166118] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2023] Open
Abstract
Cytoadhesion of Plasmodium falciparum-infected erythrocytes (IEs) to the endothelial lining of blood vessels protects parasites from splenic destruction, but also leads to detrimental inflammation and vessel occlusion. Surface display of the P. falciparum erythrocyte membrane protein 1 (PfEMP1) adhesion ligands exposes them to host antibodies and serum proteins. PfEMP1 are important targets of acquired immunity to malaria, and through evolution, the protein family has expanded and diversified to bind a select set of host receptors through antigenically diversified receptor-binding domains. Here, we show that complement component 1s (C1s) in serum cleaves PfEMP1 at semiconserved arginine motifs located at interdomain regions between the receptor-binding domains, rendering the IE incapable of binding the two main PfEMP1 receptors, CD36 and endothelial protein C receptor (EPCR). Bioinformatic analyses of PfEMP1 protein sequences from 15 P. falciparum genomes found the C1s motif was present in most PfEMP1 variants. Prediction of C1s cleavage and loss of binding to endothelial receptors was further corroborated by testing of several different parasite lines. These observations suggest that the parasites have maintained susceptibility for cleavage by the serine protease, C1s, and provides evidence for a complex relationship between the complement system and the P. falciparum cytoadhesion virulence determinant.
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Affiliation(s)
- Yvonne Azasi
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, NIH, Rockville, MD 20852
| | - Leanne M Low
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, NIH, Rockville, MD 20852
| | - Ashley N Just
- Centre for Medical Parasitology, Department of International Health, Immunology and Microbiology, University of Copenhagen, 2200 Copenhagen, Denmark
- Department of Infectious Diseases, Rigshospitalet, 2100 Copenhagen, Denmark
| | - Sai S R Raghavan
- Centre for Medical Parasitology, Department of International Health, Immunology and Microbiology, University of Copenhagen, 2200 Copenhagen, Denmark
- Department of Infectious Diseases, Rigshospitalet, 2100 Copenhagen, Denmark
| | - Christian W Wang
- Centre for Medical Parasitology, Department of International Health, Immunology and Microbiology, University of Copenhagen, 2200 Copenhagen, Denmark
- Department of Infectious Diseases, Rigshospitalet, 2100 Copenhagen, Denmark
| | - Paola Valenzuela-Leon
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, NIH, Rockville, MD 20852
| | - J Alexandra Rowe
- Centre for Immunity, Infection and Evolution, University of Edinburgh, Edinburgh EH9 3FL, United Kingdom
- Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, United Kingdom
| | - Joseph D Smith
- Center for Global Infectious Disease Resesarch, Seattle Children's Research Institute, Seattle, WA 98109
- Department of Pediatrics, University of Washington, Seattle, WA 98195
- Department of Global Health, University of Washington, Seattle, WA 98195
| | - Thomas Lavstsen
- Centre for Medical Parasitology, Department of International Health, Immunology and Microbiology, University of Copenhagen, 2200 Copenhagen, Denmark
- Department of Infectious Diseases, Rigshospitalet, 2100 Copenhagen, Denmark
| | - Louise Turner
- Centre for Medical Parasitology, Department of International Health, Immunology and Microbiology, University of Copenhagen, 2200 Copenhagen, Denmark
- Department of Infectious Diseases, Rigshospitalet, 2100 Copenhagen, Denmark
| | - Eric Calvo
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, NIH, Rockville, MD 20852;
| | - Louis H Miller
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, NIH, Rockville, MD 20852;
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38
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Cryo-EM reveals the architecture of placental malaria VAR2CSA and provides molecular insight into chondroitin sulfate binding. Nat Commun 2021; 12:2956. [PMID: 34011972 PMCID: PMC8134449 DOI: 10.1038/s41467-021-23254-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 04/16/2021] [Indexed: 12/13/2022] Open
Abstract
Placental malaria can have severe consequences for both mother and child and effective vaccines are lacking. Parasite-infected red blood cells sequester in the placenta through interaction between parasite-expressed protein VAR2CSA and the glycosaminoglycan chondroitin sulfate A (CS) abundantly present in the intervillous space. Here, we report cryo-EM structures of the VAR2CSA ectodomain at up to 3.1 Å resolution revealing an overall V-shaped architecture and a complex domain organization. Notably, the surface displays a single significantly electropositive patch, compatible with binding of negatively charged CS. Using molecular docking and molecular dynamics simulations as well as comparative hydroxyl radical protein foot-printing of VAR2CSA in complex with placental CS, we identify the CS-binding groove, intersecting with the positively charged patch of the central VAR2CSA structure. We identify distinctive conserved structural features upholding the macro-molecular domain complex and CS binding capacity of VAR2CSA as well as divergent elements possibly allowing immune escape at or near the CS binding site. These observations will support rational design of second-generation placental malaria vaccines. In placental malaria, interactions between parasite protein VAR2CSA and human glycosaminoglycan chondroitin sulfate A (CS) sequesters infected red blood cells in the placenta. Here, the authors provide cryo-EM structures of VAR2CSA and placental CS, identifying molecular interactions that could guide design of placental malaria vaccines.
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39
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Moussiliou A, Turner L, Cottrell G, Doritchamou J, Gbédandé K, Fievet N, Luty AJF, Massougbodji A, Theander TG, Deloron P, Lavstsen T, Tuikue Ndam N. Dynamics of PfEMP1 Antibody Profile From Birth to 12 Months of Age in Beninese Infants. J Infect Dis 2021; 221:2010-2017. [PMID: 32002541 DOI: 10.1093/infdis/jiaa043] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Accepted: 01/24/2020] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Plasmodium falciparum-infected erythrocytes bind to specific endothelial cell receptors via members of the PfEMP1 family exported onto the erythrocyte surface. These interactions are mediated by different types of cysteine-rich interdomain region (CIDR) domains found in the N-terminal region of all PfEMP1. CIDRα1 domains bind endothelial protein C receptor (EPCR), CIDRα2-6 domains bind CD36, whereas the receptor specificity of CIDRβ/γ/δ domains is unknown. METHODS In this study, we investigated the level of immunoglobulin (Ig)G targeting the different types of PfEMP1 CIDR during the first year of life. We used plasma collected longitudinally from children of pregnant women who had been followed closely through pregnancy. RESULTS Antibodies to CIDRα1 domains were more frequent in cord blood compared with antibodies to CIDRα2-6 domains. Higher IgG levels to EPCR-binding CIDRα1 variants positively correlated with the timing of first infections. Antibodies to all PfEMP1 types declined at similar rates to the point of disappearance over the first 6 months of life. At 12 months, children had acquired antibody to all types of CIDR domains, mostly in children with documented P falciparum infections. CONCLUSIONS These observations agree with the notion that the timing and phenotype of first P falciparum infections in life are influenced by the immune status of the mother.
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Affiliation(s)
| | - L Turner
- Centre for Medical Parasitology at 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
| | - G Cottrell
- Université de Paris, MERIT, IRD, Paris, France
| | - J Doritchamou
- Institut de Recherche Clinique du Bénin, Université d'Abomey-Calavi, Cotonou, Bénin
| | - K Gbédandé
- Institut de Recherche Clinique du Bénin, Université d'Abomey-Calavi, Cotonou, Bénin
| | - N Fievet
- Université de Paris, MERIT, IRD, Paris, France
| | - A J F Luty
- Université de Paris, MERIT, IRD, Paris, France
| | - A Massougbodji
- Institut de Recherche Clinique du Bénin, Université d'Abomey-Calavi, Cotonou, Bénin
| | - T G Theander
- Centre for Medical Parasitology at 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
| | - P Deloron
- Université de Paris, MERIT, IRD, Paris, France
| | - T Lavstsen
- Centre for Medical Parasitology at 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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Bioengineered 3D Microvessels for Investigating Plasmodium falciparum Pathogenesis. Trends Parasitol 2021; 37:401-413. [PMID: 33485788 DOI: 10.1016/j.pt.2020.12.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 12/15/2020] [Accepted: 12/25/2020] [Indexed: 12/18/2022]
Abstract
Plasmodium falciparum pathogenesis is complex and intimately connected to vascular physiology. This is exemplified by cerebral malaria (CM), a neurovascular complication that accounts for most of the malaria deaths worldwide. P. falciparum sequestration in the brain microvasculature is a hallmark of CM and is not replicated in animal models. Numerous aspects of the disease are challenging to fully understand from clinical studies, such as parasite binding tropism or causal pathways in blood-brain barrier breakdown. Recent bioengineering approaches allow for the generation of 3D microvessels and organ-specific vasculature that provide precise control of vessel architecture and flow dynamics, and hold great promise for malaria research. Here, we discuss recent and future applications of bioengineered microvessels in malaria pathogenesis research.
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41
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Structure-Guided Design of a Synthetic Mimic of an Endothelial Protein C Receptor-Binding PfEMP1 Protein. mSphere 2021; 6:6/1/e01081-20. [PMID: 33408232 PMCID: PMC7845591 DOI: 10.1128/msphere.01081-20] [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: 11/20/2022] Open
Abstract
Vaccines train our immune systems to generate antibodies which recognize pathogens. Some of these antibodies are highly protective, preventing infection, while others are ineffective. Structure-guided vaccine design provides a route to elicit a focused immune response against the most functionally important regions of a pathogen surface. This can be achieved by identifying epitopes for neutralizing antibodies through structural methods and recapitulating these epitopes by grafting their core structural features onto smaller scaffolds. In this study, we conducted a modified version of this protocol. We focused on the PfEMP1 protein family found on the surfaces of erythrocytes infected with Plasmodium falciparum. A subset of PfEMP1 proteins bind to endothelial protein C receptor (EPCR), and their expression correlates with development of the symptoms of severe malaria. Structural studies revealed that PfEMP1 molecules present a helix-kinked-helix motif that forms the core of the EPCR-binding site. Using Rosetta-based design, we successfully grafted this motif onto a three-helical bundle scaffold. We show that this synthetic binder interacts with EPCR with nanomolar affinity and adopts the expected structure. We also assessed its ability to bind to antibodies found in immunized animals and in humans from malaria-endemic regions. Finally, we tested the capacity of the synthetic binder to effectively elicit antibodies that prevent EPCR binding and analyzed the degree of cross-reactivity of these antibodies across a diverse repertoire of EPCR-binding PfEMP1 proteins. Despite our synthetic binder adopting the correct structure, we find that it is not as effective as the CIDRα domain on which it is based for inducing adhesion-inhibitory antibodies. This cautions against the rational design of focused immunogens that contain the core features of a ligand-binding site of a protein family, rather than those of a neutralizing antibody epitope. IMPORTANCE Vaccines train our immune systems to generate antibodies which recognize pathogens. Some of these antibodies are highly protective, preventing infection, while others are ineffective. Structure-guided rational approaches allow design of synthetic molecules which contain only the regions of a pathogen required to induce production of protective antibodies. On the surfaces of red blood cells infected by the malaria parasite Plasmodium falciparum are parasite molecules called PfEMP1 proteins. PfEMP1 proteins, which bind to human receptor EPCR, are linked to development of severe malaria. We have designed a synthetic protein on which we grafted the EPCR-binding surface of a PfEMP1 protein. We use this molecule to show which fraction of protective antibodies recognize the EPCR-binding surface and test its effectiveness as a vaccine immunogen.
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42
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Bewley MC, Gautam L, Jagadeeshaprasad MG, Gowda DC, Flanagan JM. Molecular architecture and domain arrangement of the placental malaria protein VAR2CSA suggests a model for carbohydrate binding. J Biol Chem 2020; 295:18589-18603. [PMID: 33122198 PMCID: PMC7939466 DOI: 10.1074/jbc.ra120.014676] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 10/13/2020] [Indexed: 11/29/2022] Open
Abstract
VAR2CSA is the placental-malaria-specific member of the antigenically variant Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) family. It is expressed on the surface of Plasmodium falciparum-infected host red blood cells and binds to specific chondroitin-4-sulfate chains of the placental proteoglycan receptor. The functional ∼310 kDa ectodomain of VAR2CSA is a multidomain protein that requires a minimum 12-mer chondroitin-4-sulfate molecule for specific, high affinity receptor binding. However, it is not known how the individual domains are organized and interact to create the receptor-binding surface, limiting efforts to exploit its potential as an effective vaccine or drug target. Using small angle X-ray scattering and single particle reconstruction from negative-stained electron micrographs of the ectodomain and multidomain constructs, we have determined the structural architecture of VAR2CSA. The relative locations of the domains creates two distinct pores that can each accommodate the 12-mer of chondroitin-4-sulfate, suggesting a model for receptor binding. This model has important implications for understanding cytoadherence of infected red blood cells and potentially provides a starting point for developing novel strategies to prevent and/or treat placental malaria.
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Affiliation(s)
- Maria C Bewley
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University College of Medicine, Milton S. Hershey Medical Center, Hershey, Pennsylvania, USA
| | - Lovely Gautam
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University College of Medicine, Milton S. Hershey Medical Center, Hershey, Pennsylvania, USA
| | - Mashanipalya G Jagadeeshaprasad
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University College of Medicine, Milton S. Hershey Medical Center, Hershey, Pennsylvania, USA
| | - D Channe Gowda
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University College of Medicine, Milton S. Hershey Medical Center, Hershey, Pennsylvania, USA.
| | - John M Flanagan
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University College of Medicine, Milton S. Hershey Medical Center, Hershey, Pennsylvania, USA.
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Structure of the Plasmodium-interspersed repeat proteins of the malaria parasite. Proc Natl Acad Sci U S A 2020; 117:32098-32104. [PMID: 33257570 PMCID: PMC7749308 DOI: 10.1073/pnas.2016775117] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The Plasmodium parasites that cause malaria replicate within blood cells of an infected host. These parasites send a small number of proteins to infected blood cell surfaces, allowing them to bind host molecules but also risking their detection by the host immune system. These proteins have diversified into large families, allowing the parasite to avoid detection by using antigenic variation. The most ubiquitous of these families is the Plasmodium-interspersed repeat (PIR) protein family. Here we present the structure of a PIR protein, revealing the architecture of its ectodomain and showing how it has diversified. Finally, we use structure-guided methods to understand which small variant surface antigen families are PIRs and to understand their evolution across malaria parasites. The deadly symptoms of malaria occur as Plasmodium parasites replicate within blood cells. Members of several variant surface protein families are expressed on infected blood cell surfaces. Of these, the largest and most ubiquitous are the Plasmodium-interspersed repeat (PIR) proteins, with more than 1,000 variants in some genomes. Their functions are mysterious, but differential pir gene expression associates with acute or chronic infection in a mouse malaria model. The membership of the PIR superfamily, and whether the family includes Plasmodium falciparum variant surface proteins, such as RIFINs and STEVORs, is controversial. Here we reveal the structure of the extracellular domain of a PIR from Plasmodium chabaudi. We use structure-guided sequence analysis and molecular modeling to show that this fold is found across PIR proteins from mouse- and human-infective malaria parasites. Moreover, we show that RIFINs and STEVORs are not PIRs. This study provides a structure-guided definition of the PIRs and a molecular framework to understand their evolution.
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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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45
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Gonzales SJ, Reyes RA, Braddom AE, Batugedara G, Bol S, Bunnik EM. Naturally Acquired Humoral Immunity Against Plasmodium falciparum Malaria. Front Immunol 2020; 11:594653. [PMID: 33193447 PMCID: PMC7658415 DOI: 10.3389/fimmu.2020.594653] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 10/07/2020] [Indexed: 12/18/2022] Open
Abstract
Malaria remains a significant contributor to the global burden of disease, with around 40% of the world's population at risk of Plasmodium infections. The development of an effective vaccine against the malaria parasite would mark a breakthrough in the fight to eradicate the disease. Over time, natural infection elicits a robust immune response against the blood stage of the parasite, providing protection against malaria. In recent years, we have gained valuable insight into the mechanisms by which IgG acts to prevent pathology and inhibit parasite replication, as well as the potential role of immunoglobulin M (IgM) in these processes. Here, we discuss recent advances in our understanding of the mechanisms, acquisition, and maintenance of naturally acquired immunity, and the relevance of these discoveries for the development of a potential vaccine against the blood stage of Plasmodium falciparum.
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Affiliation(s)
| | | | | | | | | | - Evelien M. Bunnik
- Department of Microbiology, Immunology and Molecular Genetics, Long School of Medicine, The University of Texas Health Science Center at San Antonio, San Antonio, TX, United States
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46
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Schiess N, Villabona-Rueda A, Cottier KE, Huether K, Chipeta J, Stins MF. Pathophysiology and neurologic sequelae of cerebral malaria. Malar J 2020; 19:266. [PMID: 32703204 PMCID: PMC7376930 DOI: 10.1186/s12936-020-03336-z] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Accepted: 07/13/2020] [Indexed: 12/14/2022] Open
Abstract
Cerebral malaria (CM), results from Plasmodium falciparum infection, and has a high mortality rate. CM survivors can retain life-long post CM sequelae, including seizures and neurocognitive deficits profoundly affecting their quality of life. As the Plasmodium parasite does not enter the brain, but resides inside erythrocytes and are confined to the lumen of the brain's vasculature, the neuropathogenesis leading to these neurologic sequelae is unclear and under-investigated. Interestingly, postmortem CM pathology differs in brain regions, such as the appearance of haemorragic punctae in white versus gray matter. Various host and parasite factors contribute to the risk of CM, including exposure at a young age, parasite- and host-related genetics, parasite sequestration and the extent of host inflammatory responses. Thus far, several proposed adjunctive treatments have not been successful in the treatment of CM but are highly needed. The region-specific CM neuro-pathogenesis leading to neurologic sequelae is intriguing, but not sufficiently addressed in research. More attention to this may lead to the development of effective adjunctive treatments to address CM neurologic sequelae.
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Affiliation(s)
- Nicoline Schiess
- Department of Neurology, Johns Hopkins School of Medicine, 600 N. Wolfe St., Meyer 6-113, Baltimore, MD, 21287, USA
| | - Andres Villabona-Rueda
- Malaria Research Institute, Dept Molecular Microbiology Immunology, Johns Hopkins School of Public Health, 615 N Wolfe Street, Baltimore, MD, 21205, USA
| | - Karissa E Cottier
- Malaria Research Institute, Dept Molecular Microbiology Immunology, Johns Hopkins School of Public Health, 615 N Wolfe Street, Baltimore, MD, 21205, USA.,BioIVT, 1450 South Rolling Road, Baltimore, MD, USA
| | | | - James Chipeta
- Department of Paediatrics, University Teaching Hospital, Nationalist Road, Lusaka, Zambia
| | - Monique F Stins
- Malaria Research Institute, Dept Molecular Microbiology Immunology, Johns Hopkins School of Public Health, 615 N Wolfe Street, Baltimore, MD, 21205, USA.
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47
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Structural basis for RIFIN-mediated activation of LILRB1 in malaria. Nature 2020; 587:309-312. [PMID: 32650338 PMCID: PMC7116854 DOI: 10.1038/s41586-020-2530-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 07/06/2020] [Indexed: 01/09/2023]
Abstract
The Plasmodium species that cause malaria are obligate intracellular parasites, and disease symptoms occur as they replicate within human blood. Despite risking immune detection, the parasite delivers proteins that bind host receptors to infected erythrocyte surfaces. In the causative agent of the most deadly human malaria, Plasmodium falciparum, RIFINs form the largest erythrocyte surface protein family1. Some RIFINs can bind inhibitory immune receptors, acting as targets for unusual antibodies containing a LAIR1 ectodomain2-4, or as ligands for LILRB15. RIFINs stimulate LILRB1 activation and signalling5, thereby potentially dampening human immune responses. To understand this process, we determined a structure of a RIFIN bound to LILRB1. We show that the RIFIN mimics the natural activating ligand of LILRB1, MHC class I, in its LILRB1-binding mode. A single RIFIN mutation disrupts the complex, blocks LILRB1 binding by all tested RIFINs and abolishes signalling in a reporter assay. In a supported lipid bilayer system, which mimics NK cell activation by antibody- dependent cell-mediated cytotoxicity, both RIFIN and MHC are recruited to the NK cell immunological synapse and reduce cell activation, as measured by perforin mobilisation. Therefore, LILRB1-binding RIFINs mimic the binding mode of the natural ligand of LILRB1 and suppress NK cell function.
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48
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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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49
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Oteng EK, Gu W, McKeague M. High-efficiency enrichment enables identification of aptamers to circulating Plasmodium falciparum-infected erythrocytes. Sci Rep 2020; 10:9706. [PMID: 32546848 PMCID: PMC7298056 DOI: 10.1038/s41598-020-66537-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2020] [Accepted: 05/04/2020] [Indexed: 01/08/2023] Open
Abstract
Plasmodium falciparum is the causative agent of the deadliest human malaria. New molecules are needed that can specifically bind to erythrocytes that are infected with P. falciparum for diagnostic purposes, to disrupt host-parasite interactions, or to deliver chemotherapeutics. Aptamer technology has the potential to revolutionize biological diagnostics and therapeutics; however, broad adoption is hindered by the high failure rate of the systematic evolution of ligands by exponential enrichment (SELEX). Here we performed parallel SELEX experiments to compare the impact of two different methods for single-strand recovery on the efficiency of aptamer enrichment. Our experimental results and analysis of SELEX publications spanning 13 years implicate the alkaline denaturation step as a significant cause for inefficient aptamer selection. Thus, we applied an exonuclease single-strand recovery step in our SELEX to direct aptamers to the surface of erythrocytes infected with P. falciparum. The selected aptamers bind with high affinity (low nanomolar Kd values) and selectivity to exposed surface proteins of both laboratory parasite strains as well isolates from patients in Asia and Africa with clinical malaria. The results obtained in this study potentially open new approaches to malaria diagnosis and surveillance.
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Affiliation(s)
- Eugene K Oteng
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, 20852, USA.
| | - Wenjuan Gu
- Clinical Research Directorate/Clinical Monitoring Research Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, Maryland, 21702, USA
| | - Maureen McKeague
- Department of Pharmacology and Therapeutics, McGill University, 3655 Prom. Sir-William-Osler, Montreal, Quebec, H3G 1Y6, Canada.,Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec, H3A 0B8, Canada
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50
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Pereira DMS, Carvalho Júnior AR, Lacerda EMDCB, da Silva LCN, Marinho CRF, André E, Fernandes ES. Oxidative and nitrosative stresses in cerebral malaria: can we target them to avoid a bad prognosis? J Antimicrob Chemother 2020; 75:1363-1373. [PMID: 32105324 DOI: 10.1093/jac/dkaa032] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
There is currently a global effort to reduce malaria morbidity and mortality. However, malaria still results in the deaths of thousands of people every year. Malaria is caused by Plasmodium spp., parasites transmitted through the bite of an infected female Anopheles mosquito. Treatment timing plays a decisive role in reducing mortality and sequelae associated with the severe forms of the disease such as cerebral malaria (CM). The available antimalarial therapy is considered effective but parasite resistance to these drugs has been observed in some countries. Antimalarial drugs act by increasing parasite lysis, especially through targeting oxidative stress pathways. Here we discuss the roles of reactive oxygen species and reactive nitrogen intermediates in CM as a result of host-parasite interactions. We also present evidence of the potential contribution of oxidative and nitrosative stress-based antimalarial drugs to disease treatment and control.
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Affiliation(s)
| | | | | | | | | | - Eunice André
- Departamento de Farmacologia, Universidade Federal do Paraná, Curitiba, PR, Brazil
| | - Elizabeth Soares Fernandes
- Programa de Pós-graduação, Universidade CEUMA, São Luís, MA, Brazil.,Instituto de Pesquisa Pelé Pequeno Príncipe, Curitiba, PR, Brazil.,Faculdades Pequeno Príncipe, Curitiba, PR, Brazil
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