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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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2
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Blankson SO, Dikroh L, Tettey P, Tornyigah B, Adamou R, Moussiliou A, Alao MJ, Amoussou A, Padounou C, Milet J, Mensah BA, Aniweh Y, Ndam NT, Roussilhon C, Tahar R. Association of Endothelial Protein C Receptor (EPCR) rs867186 Gene Polymorphism With Increased Levels of Soluble EPCR and High Risk of Severe Malaria and Fatality in Beninese Children. J Infect Dis 2023; 227:179-182. [PMID: 36416015 DOI: 10.1093/infdis/jiac461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 11/18/2022] [Accepted: 11/22/2022] [Indexed: 11/24/2022] Open
Abstract
The endothelial protein C receptor (EPCR)-rs867186 G allele has been linked to high plasma levels of soluble EPCR (sEPCR) and controversially associated with either susceptibility or resistance to severe and cerebral malaria. In this study, quantitative enzyme-linked immunosorbent assay and sequencing were used to assess sEPCR levels and EPCR-rs867186 polymorphism in blood samples from Beninese children with different clinical presentations of malaria. Our findings show that sEPCR levels were higher at hospital admission than during convalescence and that EPCR-rs867186 G allele was associated with increased sEPCR plasma levels, malaria severity, and mortality rate (P < .001, P = .03, and P = .04, respectively), suggesting a role of sEPCR in the pathogenesis of severe malaria.
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Affiliation(s)
- Samuel Odarkwei Blankson
- Université de Paris Cité, MERIT, IRD, Paris, France.,West African Centre for Cell Biology of Infectious Pathogens, Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, Accra, Ghana
| | - Liliane Dikroh
- Department of Immunology and Department of Parasitology, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Patrick Tettey
- Department of Immunology and Department of Parasitology, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Bernard Tornyigah
- Université de Paris Cité, MERIT, IRD, Paris, France.,Department of Immunology and Department of Parasitology, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Rafiou Adamou
- Université de Paris Cité, MERIT, IRD, Paris, France.,Institut de Recherche Clinique du Benin, Calavi, Benin
| | - Azizath Moussiliou
- Université de Paris Cité, MERIT, IRD, Paris, France.,Institut de Recherche Clinique du Benin, Calavi, Benin
| | - Maroufou J Alao
- Département de Pédiatrie, Centre Hospitalier Universitaire de La Mère et De L'Enfant Lagune, Cotonou, Benin
| | - Annick Amoussou
- Service de Pédiatrie, Centre Hospitalo-Universitaire, Suruléré, Cotonou, Benin
| | - Caroline Padounou
- Centre Hospitalier Universitaire de l'Oueme/Plateau, Porto-Novo, Benin
| | | | - Benedicta Ayiedu Mensah
- Department of Immunology and Department of Parasitology, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Yaw Aniweh
- West African Centre for Cell Biology of Infectious Pathogens, Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, Accra, Ghana
| | - Nicaise Tuikue Ndam
- Université de Paris Cité, MERIT, IRD, Paris, France.,West African Centre for Cell Biology of Infectious Pathogens, Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, Accra, Ghana
| | | | - Rachida Tahar
- Université de Paris Cité, MERIT, IRD, Paris, France.,West African Centre for Cell Biology of Infectious Pathogens, Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, Accra, Ghana
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3
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Cespedes JC, Hibbert J, Krishna S, Yan F, Bharti PK, Stiles JK, Liu M. Association of EPCR Polymorphism rs867186-GG With Severity of Human Malaria. Front Genet 2020; 11:56. [PMID: 32153634 PMCID: PMC7050639 DOI: 10.3389/fgene.2020.00056] [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: 05/30/2019] [Accepted: 01/17/2020] [Indexed: 11/14/2022] Open
Abstract
Background Cerebral malaria (CM) is characterized by the sequestration of Plasmodium-infected erythrocytes (pRBCs) to host brain microvasculature beds via P. falciparum erythrocyte membrane protein 1 (PfEMP1). Under normal conditions, activated protein C (APC) bound to endothelial protein C receptor (EPCR) has cytoprotective properties via the activation of protease-activated receptor 1 (PAR1). During malaria infection, pRBCs transports PfEMP1 to the membranes to bind EPCR in the same region as APC. As a result, APC is less capable of inducing cytoprotective effects via PAR1. Two studies involving adult malaria patients revealed that EPCR rs867186-GG allele is associated with protection against severe malaria, while three other studies involving child malaria patients could not show association between EPCR rs867186-GG genotype and severe malaria or increased mortality among children with CM. Methods We examined the association between the EPCR rs867186-GG genotype and the protection against cerebral malaria. Peripheral blood samples were collected from 47 malaria patients and 34 healthy individuals from a study conducted from 2004 to 2007 at the NSCB Medical College Hospital in India. CM and malaria-associated complications were defined based on WHO criteria. Genomic DNA was isolated from the peripheral blood mononuclear cells. Primer sequences were designed to contain rs867186 of the PROCR gene (NM 006404) and were used to amplify a 660 bp product as described before. PCR products were purified, and DNA sequences were determined by Sanger Sequencing (Genewiz, NJ). Nonparametric tests were used to compare the groups. To analyze differences in allele frequencies, we used chi-squared or Fisher's exact tests for categorical variables if the expected values were less than 5. P-value <0.05 was considered statistically significant. Results Our results showed significantly higher rates of AG and GG genotypes in CM patients compared to mild malaria (P = 0.0034). Conclusion Our results indicate that rs867186-GG or rs867186-AG genotypes are not associated with protection against HCM.
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Affiliation(s)
- Juan Carlos Cespedes
- Department of Microbiology, Biochemistry and Immunology, Morehouse School of Medicine, Atlanta, GA, United States
| | - Jacqueline Hibbert
- Department of Microbiology, Biochemistry and Immunology, Morehouse School of Medicine, Atlanta, GA, United States
| | - Sri Krishna
- National Institute for Research in Tribal Health (NIRTH), Jabalpur, India
| | - Fengxia Yan
- Department of Microbiology, Biochemistry and Immunology, Morehouse School of Medicine, Atlanta, GA, United States
| | - Praveen K Bharti
- National Institute for Research in Tribal Health (NIRTH), Jabalpur, India
| | - Jonathan K Stiles
- Department of Microbiology, Biochemistry and Immunology, Morehouse School of Medicine, Atlanta, GA, United States
| | - Mingli Liu
- Department of Microbiology, Biochemistry and Immunology, Morehouse School of Medicine, Atlanta, GA, United States
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4
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Jensen AR, Adams Y, Hviid L. Cerebral Plasmodium falciparum malaria: The role of PfEMP1 in its pathogenesis and immunity, and PfEMP1-based vaccines to prevent it. Immunol Rev 2020; 293:230-252. [PMID: 31562653 PMCID: PMC6972667 DOI: 10.1111/imr.12807] [Citation(s) in RCA: 81] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 09/04/2019] [Accepted: 09/09/2019] [Indexed: 12/13/2022]
Abstract
Malaria, a mosquito-borne infectious disease caused by parasites of the genus Plasmodium continues to be a major health problem worldwide. The unicellular Plasmodium-parasites have the unique capacity to infect and replicate within host erythrocytes. By expressing variant surface antigens Plasmodium falciparum has evolved to avoid protective immune responses; as a result in endemic areas anti-malaria immunity develops gradually over many years of multiple and repeated infections. We are studying the role of Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) expressed by asexual stages of P. falciparum responsible for the pathogenicity of severe malaria. The immunopathology of falciparum malaria has been linked to cyto-adhesion of infected erythrocytes to specific host receptors. A greater appreciation of the PfEMP1 molecules important for the development of protective immunity and immunopathology is a prerequisite for the rational discovery and development of a safe and protective anti-disease malaria vaccine. Here we review the role of ICAM-1 and EPCR receptor adhering falciparum-parasites in the development of severe malaria; we discuss our current research to understand the factors involved in the pathogenesis of cerebral malaria and the feasibility of developing a vaccine targeted specifically to prevent this disease.
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Affiliation(s)
- Anja Ramstedt Jensen
- Centre for Medical Parasitology at Department of Immunology and MicrobiologyFaculty of Health and Medical SciencesUniversity of CopenhagenCopenhagenDenmark
| | - Yvonne Adams
- Centre for Medical Parasitology at Department of Immunology and MicrobiologyFaculty of Health and Medical SciencesUniversity of CopenhagenCopenhagenDenmark
| | - Lars Hviid
- Centre for Medical Parasitology at Department of Immunology and MicrobiologyFaculty of Health and Medical SciencesUniversity of CopenhagenCopenhagenDenmark
- Department of Infectious DiseasesRigshospitaletCopenhagenDenmark
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5
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Chesnokov O, Merritt J, Tcherniuk SO, Milman N, Oleinikov AV. Plasmodium falciparum infected erythrocytes can bind to host receptors integrins αVβ3 and αVβ6 through DBLδ1_D4 domain of PFL2665c PfEMP1 protein. Sci Rep 2018; 8:17871. [PMID: 30552383 PMCID: PMC6294747 DOI: 10.1038/s41598-018-36071-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Accepted: 11/14/2018] [Indexed: 02/05/2023] Open
Abstract
Major complications and mortality from Plasmodium falciparum malaria are associated with cytoadhesion of parasite-infected erythrocytes (IE). The main parasite ligands for cytoadhesion are members of the P. falciparum erythrocyte membrane protein 1 (PfEMP1) family. Interactions of different host receptor-ligand pairs may lead to various pathological outcomes, like placental or cerebral malaria. It has been shown previously that IE can bind integrin αVβ3. Using bead-immobilized PfEMP1 constructs, we have identified that the PFL2665c DBLδ1_D4 domain binds to αVβ3 and αVβ6. A parasite line expressing PFL2665c binds to surface-immobilized αVβ3 and αVβ6; both are RGD motif-binding integrins. Interactions can be inhibited by cyloRGDFV peptide, an antagonist of RGD-binding integrins. This is a first, to the best of our knowledge, implication of a specific PfEMP1 domain for binding to integrins. These host receptors have important physiological functions in endothelial and immune cells; therefore, these results will contribute to future studies and a better understanding, at the molecular level, of the physiological outcome of interactions between IE and integrin receptors on the surface of host cells.
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Affiliation(s)
- Olga Chesnokov
- Charles E. Schmidt College of Medicine, Department of Biomedical Science, Florida Atlantic University, Boca Raton, FL, USA
| | - Jordan Merritt
- Charles E. Schmidt College of Medicine, Department of Biomedical Science, Florida Atlantic University, Boca Raton, FL, USA
| | - Sergey O Tcherniuk
- Charles E. Schmidt College of Medicine, Department of Biomedical Science, Florida Atlantic University, Boca Raton, FL, USA
| | - Neta Milman
- Seattle Biomedical Research Institute, Seattle, WA, USA
| | - Andrew V Oleinikov
- Charles E. Schmidt College of Medicine, Department of Biomedical Science, Florida Atlantic University, Boca Raton, FL, USA.
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6
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Olsen RW, Ecklu-Mensah G, Bengtsson A, Ofori MF, Lusingu JPA, Castberg FC, Hviid L, Adams Y, Jensen ATR. Natural and Vaccine-Induced Acquisition of Cross-Reactive IgG-Inhibiting ICAM-1-Specific Binding of a Plasmodium falciparum PfEMP1 Subtype Associated Specifically with Cerebral Malaria. Infect Immun 2018; 86:e00622-17. [PMID: 29426042 PMCID: PMC5865037 DOI: 10.1128/iai.00622-17] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Accepted: 01/25/2018] [Indexed: 12/17/2022] Open
Abstract
Cerebral malaria (CM) is a potentially deadly outcome of Plasmodium falciparum malaria that is precipitated by sequestration of infected erythrocytes (IEs) in the brain. The adhesion of IEs to brain endothelial cells is mediated by a subtype of parasite-encoded erythrocyte membrane protein 1 (PfEMP1) that facilitates dual binding to host intercellular adhesion molecule 1 (ICAM-1) and endothelial protein receptor C (EPCR). The PfEMP1 subtype is characterized by the presence of a particular motif (DBLβ_motif) in the constituent ICAM-1-binding DBLβ domain. The rate of natural acquisition of DBLβ_motif-specific IgG antibodies and the ability to induce such antibodies by vaccination are unknown, and the aim of this study was to provide such data. We used an enzyme-linked immunosorbent assay (ELISA) to measure DBLβ-specific IgG in plasma from Ghanaian children with malaria. The ability of human immune plasma and DBLβ-specific rat antisera to inhibit the interaction between ICAM-1 and DBLβ was assessed using ELISA and in vitro assays of IE adhesion under flow. The acquisition of DBLβ_motif-specific IgG coincided with age-specific susceptibility to CM. Broadly cross-reactive antibodies inhibiting the interaction between ICAM-1 and DBLβ_motif domains were detectable in immune plasma and in sera of rats immunized with specific DBLβ_motif antigens. Importantly, antibodies against the DBLβ_motif inhibited ICAM-1-specific in vitro adhesion of erythrocytes infected by four of five P. falciparum isolates from cerebral malaria patients. We conclude that natural exposure to P. falciparum as well as immunization with specific DBLβ_motif antigens can induce cross-reactive antibodies that inhibit the interaction between ICAM-1 and a broad range of DBLβ_motif domains. These findings raise hope that a vaccine designed specifically to prevent CM is feasible.
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MESH Headings
- Adolescent
- Amino Acid Motifs
- Antibodies, Neutralizing/immunology
- Antibodies, Protozoan/immunology
- Antigens, Protozoan/immunology
- Binding Sites
- Child
- Child, Preschool
- Cross Reactions/immunology
- Ghana
- Humans
- Immunoglobulin G/immunology
- Immunoglobulin G/metabolism
- Infant
- Intercellular Adhesion Molecule-1/metabolism
- Malaria Vaccines/immunology
- Malaria, Cerebral/immunology
- Malaria, Cerebral/metabolism
- Malaria, Cerebral/parasitology
- Malaria, Falciparum/immunology
- Malaria, Falciparum/metabolism
- Malaria, Falciparum/parasitology
- Plasmodium falciparum/immunology
- Protein Binding/immunology
- Protein Interaction Domains and Motifs
- Protozoan Proteins/chemistry
- Protozoan Proteins/immunology
- Protozoan Proteins/metabolism
- Tanzania
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Affiliation(s)
- Rebecca W Olsen
- Centre for Medical Parasitology at Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Gertrude Ecklu-Mensah
- Centre for Medical Parasitology at 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
| | - Anja Bengtsson
- Centre for Medical Parasitology at Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Michael F Ofori
- Department of Immunology, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
| | - John P A Lusingu
- National Institute for Medical Research, Tanga Centre, Tanga City, Tanzania
| | - Filip C Castberg
- Centre for Medical Parasitology at Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Clinical Microbiology, Copenhagen University Hospital (Rigshospitalet), Copenhagen, Denmark
| | - Lars Hviid
- Centre for Medical Parasitology at Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), Copenhagen, Denmark
| | - Yvonne Adams
- Centre for Medical Parasitology at Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Anja T R Jensen
- Centre for Medical Parasitology at Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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Maknitikul S, Luplertlop N, Grau GER, Ampawong S. Dysregulation of pulmonary endothelial protein C receptor and thrombomodulin in severe falciparum malaria-associated ARDS relevant to hemozoin. PLoS One 2017; 12:e0181674. [PMID: 28732053 PMCID: PMC5521846 DOI: 10.1371/journal.pone.0181674] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Accepted: 07/04/2017] [Indexed: 12/20/2022] Open
Abstract
To investigate the role of the protein C system, endothelial protein C receptor (EPCR) and thrombomodulin (TM) in the pathogenesis of malaria-associated acute respiratory distress syndrome (ARDS) in relation to hemozoin and proinflammatory cytokines-induced type II pneumocyte injury and -aggravated pulmonary resolution. A total of 29 left-over lung specimens that were obtained from patients who died from severe falciparum malaria were examined. Histopathological, immunohistochemical and electron microscopic analyses revealed that ARDS coexisted with pulmonary edema and systemic bleeding; the severity was dependent on the level of hemozoin deposition in the lung and internal alveolar hemorrhaging. The loss of EPCR and TM was primarily identified in ARDS patients and was related to the level of hemozoin, parasitized red blood cell (PRBC) and white blood cell accumulation in the lung. Moreover, an in vitro analysis demonstrated that interleukin-13 and -31 and hemozoin induced pneumocytic cell injury and apoptosis, as assessed by EB/AO staining, electron microscopy and the up-regulation of CARD-9 mRNA (caspase recruitment domain-9 messenger-ribonucleic acid). The dysregulation of EPCR and TM in the lung, especially in those with increased levels of hemozoin, may play an important role in the pathogenesis of malaria-associated ARDS through an apoptotic pathway.
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Affiliation(s)
- Sitang Maknitikul
- Department of Tropical Pathology, Faculty of Tropical Medicine, Mahidol University, Ratchathewi, Bangkok, Thailand
| | - Natthanej Luplertlop
- Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Ratchathewi, Bangkok, Thailand
| | - Georges E. R. Grau
- Vascular Immunology, Department of Pathology, Sydney Medical School, The University of Sydney, Camperdown, NSW, Australia
| | - Sumate Ampawong
- Department of Tropical Pathology, Faculty of Tropical Medicine, Mahidol University, Ratchathewi, Bangkok, Thailand
- * E-mail:
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Marquet S. Overview of human genetic susceptibility to malaria: From parasitemia control to severe disease. INFECTION GENETICS AND EVOLUTION 2017; 66:399-409. [PMID: 28579526 DOI: 10.1016/j.meegid.2017.06.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 05/31/2017] [Accepted: 06/01/2017] [Indexed: 10/19/2022]
Abstract
Malaria is a life-threatening blood disease caused by the protozoan Plasmodium. Infection may lead to several different patterns of symptoms in the host: asymptomatic state, uncomplicated disease or severe disease. Severe malaria occurs mostly in young children and is a major cause of death. Disease is thought to result from the sequestration of parasites in the small blood vessels of the brain and the deregulation of key immune system elements. The cellular and molecular regulatory mechanisms underlying the pathogenesis of disease are however not fully understood. What is known it is that the genetic determinants of the host play an important role in the severity of the disease and the outcome of infection. Here we review the most convincing results obtained through genetic epidemiology studies concerning the genetic control of malaria in human caused by Plasmodium falciparum infection. The identification of genes conferring susceptibility or resistance to malaria might improve diagnosis and treatment.
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Affiliation(s)
- Sandrine Marquet
- Aix-Marseille University, INSERM, GIMP, Labex ParaFrap, Marseille, France.
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9
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Liang Y, Huang X, Jiang Y, Qin Y, Peng D, Huang Y, Li J, Sooranna SR, Pinhu L. Endothelial protein C receptor polymorphisms and risk of sepsis in a Chinese population. J Int Med Res 2017; 45:504-513. [PMID: 28415941 PMCID: PMC5536666 DOI: 10.1177/0300060516686496] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Objective To examine the potential relationship of EPCR polymorphisms and the risk of sepsis in a Chinese population. Methods Snapshot SNP genotyping assays and DNA sequencing methods were used to detect polymorphisms of the EPCR gene, rs2069948C/T (2532C/T) and rs867186A/G (6936A/G), in 64 patients with sepsis and in 113 controls. Soluble EPCR (sEPCR) was measured by ELISA. Results There were significant differences in the allele and genotype frequencies of EPCR gene rs2069948C/T and allele frequencies of rs867186A/G between male and female patients and controls. Females carrying rs2069948 C/T genotype or T allele and males carrying rs867186 A allele were associated with a significantly increased risk of sepsis. Plasma sEPCR levels of sepsis patients were higher than controls and showed no correlation with EPCR gene polymorphisms. Conclusions EPCR polymorphisms may be associated with increased risk of sepsis, but this has no effect on the release of sEPCR in patients with sepsis.
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Affiliation(s)
- Yanbing Liang
- 1 Affiliated Hospital of Youjiang Medical University, Baise, Guangxi, PR China
| | - Xia Huang
- 1 Affiliated Hospital of Youjiang Medical University, Baise, Guangxi, PR China
| | - Yujie Jiang
- 1 Affiliated Hospital of Youjiang Medical University, Baise, Guangxi, PR China
| | - Yueqiu Qin
- 1 Affiliated Hospital of Youjiang Medical University, Baise, Guangxi, PR China
| | - Dingwei Peng
- 1 Affiliated Hospital of Youjiang Medical University, Baise, Guangxi, PR China
| | - Yuqing Huang
- 1 Affiliated Hospital of Youjiang Medical University, Baise, Guangxi, PR China
| | - Jin Li
- 1 Affiliated Hospital of Youjiang Medical University, Baise, Guangxi, PR China
| | - Suren R Sooranna
- 2 Department of Surgery and Cancer, Imperial College London, Chelsea and Westminster Hospital, London, UK
| | - Liao Pinhu
- 1 Affiliated Hospital of Youjiang Medical University, Baise, Guangxi, PR China
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10
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Adukpo S, Gyan BA, Ofori MF, Dodoo D, Velavan TP, Meyer CG. Triggering receptor expressed on myeloid cells 1 (TREM-1) and cytokine gene variants in complicated and uncomplicated malaria. Trop Med Int Health 2016; 21:1592-1601. [PMID: 27671831 DOI: 10.1111/tmi.12787] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND Malaria elicits inflammatory responses, which, if not well regulated, may exert detrimental effects. When activated, triggering receptor expressed on myeloid cells 1 (TREM-1) enhances inflammatory responses by increasing secretion of IL-8 and other Th1 cytokines. In contrast, TREM-like transcript 1 (TREML-1) promotes anti-inflammatory responses by binding to TREM-1 ligands and competing with TREM-1, thus antagonizing TREM-1 activation to reduce inflammation. Endothelial protein C receptor (EPCR) also mediates anti-inflammatory responses by activating endothelial protein C (PC). Upon microbial stimulation, soluble forms of TREM-1 (sTREM-1) and soluble EPCR (sEPCR) are released. Their plasma levels reflect the degree of inflammation and the severity of infection. METHODS In a cross-sectional study comparing patients with severe with uncomplicated malaria, sTREM-1, soluble TREML-1 (sTREML-1) and sEPCR plasma levels as well as plasma levels of sEPCR derived from convalescent patients were quantified. Samples were collected on admittance of paediatric patients infected with Plasmodium falciparum to hospitals in Accra, Ghana. Distinct genetic regions of the genes encoding TREM-1, EPCR, interleukin (IL)-8 and IL-18 encompassing known genetic polymorphisms that influence plasma levels underwent DNA sequencing. RESULTS Higher sTREM-1 levels were observed among children suffering from severe malaria compared to those with uncomplicated malaria (P = 0.049). Low TREM-1 to TREML-1 ratios were associated with uncomplicated malaria (P = 0.033). The TREM1 rs2234237T variant causing the amino acid exchange Thr25Ser, which has been associated with higher TREM-1 plasma levels, was significantly more frequent among patients with severe malaria than in those with uncomplicated malaria (P = 0.036). Low levels of sEPCR were observed in severe and uncomplicated malaria, while variant genotypes of IL8, IL18 and EPCR did not show any association. CONCLUSION Higher plasma levels of sTREM-1 alone or relative to sTREML-1 during malaria predispose to the phenotype of severe malaria. Carriage of the TREM1 rs2234237T allele appears to be a risk factor for the development of severe malaria.
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Affiliation(s)
- Selorme Adukpo
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany.,Immunology Department, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Accra, Ghana
| | - Ben A Gyan
- Immunology Department, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Accra, Ghana
| | - Michael F Ofori
- Immunology Department, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Accra, Ghana
| | - Daniel Dodoo
- Immunology Department, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Accra, Ghana
| | - Thirumalaisamy P Velavan
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany.,Fondation Congolaise pour la Recherche Médicale, Brazzaville, Republic of Congo.,Duy Tan University, Da Nang, Vietnam
| | - Christian G Meyer
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany.,Duy Tan University, Da Nang, Vietnam
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The endothelial protein C receptor rs867186-GG genotype is associated with increased soluble EPCR and could mediate protection against severe malaria. Sci Rep 2016; 6:27084. [PMID: 27255786 PMCID: PMC4891778 DOI: 10.1038/srep27084] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Accepted: 04/29/2016] [Indexed: 11/23/2022] Open
Abstract
The endothelial protein C receptor (EPCR) appears to play an important role in Plasmodium falciparum endothelial cell binding in severe malaria (SM). Despite consistent findings of elevated soluble EPCR (sEPCR) in other infectious diseases, field studies to date have provided conflicting data about the role of EPCR in SM. To better define this role, we performed genotyping for the rs867186-G variant, associated with increased sEPCR levels, and measured sEPCR levels in two prospective studies of Ugandan children designed to understand immunologic and genetic factors associated with neurocognitive deficits in SM including 551 SM children, 71 uncomplicated malaria (UM) and 172 healthy community children (CC). The rs867186-GG genotype was more frequent in CC (4.1%) than SM (0.6%, P = 0.002). The rs867186-G variant was associated with increased sEPCR levels and sEPCR was lower in children with SM than CC (P < 0.001). Among SM children, those who had a second SM episode showed a trend toward lower plasma sEPCR both at initial admission and at 6-month follow-up compared to those without repeated SM (P = 0.06 for both). The study findings support a role for sEPCR in severe malaria pathogenesis and emphasize a distinct role of sEPCR in malaria as compared to other infectious diseases.
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12
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Emerging roles for hemostatic dysfunction in malaria pathogenesis. Blood 2016; 127:2281-8. [PMID: 26851291 DOI: 10.1182/blood-2015-11-636464] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Accepted: 01/27/2016] [Indexed: 11/20/2022] Open
Abstract
Severe Plasmodium falciparum malaria remains a leading cause of mortality, particularly in sub-Saharan Africa where it accounts for up to 1 million deaths per annum. In spite of the significant mortality and morbidity associated with cerebral malaria (CM), the molecular mechanisms involved in the pathophysiology of severe malaria remain surprisingly poorly understood. Previous studies have demonstrated that sequestration of P falciparum-infected erythrocytes within the microvasculature of the brain plays a key role in the development of CM. In addition, there is convincing evidence that both endothelial cell activation and platelets play critical roles in the modulating the pathogenesis of severe P falciparum malaria. In this review, we provide an overview of recent studies that have identified novel roles through which hemostatic dysfunction may directly influence malaria pathogenesis. In particular, we focus on emerging data suggesting that von Willebrand factor, coagulation cascade activation, and dysfunction of the protein C pathway may be of specific importance in this context. These collective insights underscore a growing appreciation of the important, but poorly understood, role of hemostatic dysfunction in malaria progression and, importantly, illuminate potential approaches for novel therapeutic strategies. Given that the mortality rate associated with CM remains on the order of 20% despite the availability of effective antimalarial therapy, development of adjunctive therapies that can attenuate CM progression clearly represents a major unmet need. These emerging data are thus not only of basic scientific interest, but also of direct clinical significance.
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13
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Nunes-Silva S, Dechavanne S, Moussiliou A, Pstrąg N, Semblat JP, Gangnard S, Tuikue-Ndam N, Deloron P, Chêne A, Gamain B. Beninese children with cerebral malaria do not develop humoral immunity against the IT4-VAR19-DC8 PfEMP1 variant linked to EPCR and brain endothelial binding. Malar J 2015; 14:493. [PMID: 26646943 PMCID: PMC4672576 DOI: 10.1186/s12936-015-1008-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Accepted: 11/21/2015] [Indexed: 11/16/2022] Open
Abstract
Background Malaria is still one of the most prevalent infectious diseases in the world. Sequestration of infected erythrocytes (IEs) is the prime mediator of disease. Cytoadhesion of IEs is mediated by members of the highly diverse Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1). A restricted sub-set of var genes encoding for PfEMP1s possessing the domain cassettes DC8 and DC13 were found to bind to the endothelial protein C receptor (EPCR). These var genes were shown to be highly expressed by parasites from patients with severe malaria clinical outcomes compared to those from patients with uncomplicated symptoms. Methods In order to further study the molecular mechanisms underlying DC8/DC13 expressing IEs adhesion to EPCR, a method was developed to produce highly pure recombinant EPCR. The IT4 parasite strain was selected on either anti-IT4-VAR19 purified IgG, EPCR or human brain endothelial cell line and their var gene expression profiles as well as their binding phenotypes were compared. The N-terminal region of IT4-VAR19 comprising a full-length DC8 cassette as well as the single EPCR binding CIDRα1.1 domain were also produced, and their immune recognition (IgG) was assessed using plasma samples from Beninese children presenting acute mild malaria, severe malaria or cerebral malaria at the time of their admission to the clinic, and from convalescent-phase plasma collected 30 days after anti-malarial treatment. Results The multi-domain VAR19-NTS-DBLγ6 binds to EPCR with a greater affinity than the CIDRα1.1 domain alone and this study also demonstrates that VAR19-NTS-DBLγ6 binding to the EPCR-expressing endothelial cell line (HBEC5i) is more pronounced than that of the CIDRα1.1 domain alone. IT4-VAR19 represents the preferentially expressed-PfEMP1 when FCR3-IEs are selected based on their capability to bind EPCR. Notably, no significant difference in the levels of antibodies towards IT4-VAR19 antigens was observed within all clinical groups between plasma samples collected during the acute malaria phase compared to samples collected 30 days after anti-malaria treatment. Conclusions These data indicate that even being the preferentially selected IT4-EPCR-binding variant, the IT4-VAR19-DC8 region does not appear to be associated with the acquisition of antibodies during a single severe paediatric malaria episode in Benin. Electronic supplementary material The online version of this article (doi:10.1186/s12936-015-1008-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Sofia Nunes-Silva
- Inserm UMR_1134, Paris, France. .,Université Paris Diderot, Sorbonne Paris Cité, UMR_S1134, Paris, France. .,Institut National de la Transfusion Sanguine, 6 rue Alexandre Cabanel, 75015, Paris, France. .,Laboratory of Excellence GR-Ex, Paris, France.
| | - Sébastien Dechavanne
- Inserm UMR_1134, Paris, France. .,Université Paris Diderot, Sorbonne Paris Cité, UMR_S1134, Paris, France. .,Institut National de la Transfusion Sanguine, 6 rue Alexandre Cabanel, 75015, Paris, France. .,Laboratory of Excellence GR-Ex, Paris, France.
| | - Azizath Moussiliou
- Laboratory of Excellence GR-Ex, Paris, France. .,Institut de Recherche pour le développement, UMR_216, Mère et enfant face aux infections tropicales, Paris, France. .,Faculté de pharmacie, PRES Sorbonne Paris Cité, Paris, France.
| | - Natalia Pstrąg
- Inserm UMR_1134, Paris, France. .,Université Paris Diderot, Sorbonne Paris Cité, UMR_S1134, Paris, France. .,Institut National de la Transfusion Sanguine, 6 rue Alexandre Cabanel, 75015, Paris, France. .,Laboratory of Excellence GR-Ex, Paris, France.
| | - Jean-Philippe Semblat
- Inserm UMR_1134, Paris, France. .,Université Paris Diderot, Sorbonne Paris Cité, UMR_S1134, Paris, France. .,Institut National de la Transfusion Sanguine, 6 rue Alexandre Cabanel, 75015, Paris, France. .,Laboratory of Excellence GR-Ex, Paris, France.
| | - Stéphane Gangnard
- Inserm UMR_1134, Paris, France. .,Université Paris Diderot, Sorbonne Paris Cité, UMR_S1134, Paris, France. .,Institut National de la Transfusion Sanguine, 6 rue Alexandre Cabanel, 75015, Paris, France. .,Laboratory of Excellence GR-Ex, Paris, France.
| | - Nicaise Tuikue-Ndam
- Laboratory of Excellence GR-Ex, Paris, France. .,Institut de Recherche pour le développement, UMR_216, Mère et enfant face aux infections tropicales, Paris, France. .,Faculté de pharmacie, PRES Sorbonne Paris Cité, Paris, France.
| | - Philippe Deloron
- Laboratory of Excellence GR-Ex, Paris, France. .,Institut de Recherche pour le développement, UMR_216, Mère et enfant face aux infections tropicales, Paris, France. .,Faculté de pharmacie, PRES Sorbonne Paris Cité, Paris, France.
| | - Arnaud Chêne
- Inserm UMR_1134, Paris, France. .,Université Paris Diderot, Sorbonne Paris Cité, UMR_S1134, Paris, France. .,Institut National de la Transfusion Sanguine, 6 rue Alexandre Cabanel, 75015, Paris, France. .,Laboratory of Excellence GR-Ex, Paris, France.
| | - Benoît Gamain
- Inserm UMR_1134, Paris, France. .,Université Paris Diderot, Sorbonne Paris Cité, UMR_S1134, Paris, France. .,Institut National de la Transfusion Sanguine, 6 rue Alexandre Cabanel, 75015, Paris, France. .,Laboratory of Excellence GR-Ex, Paris, France.
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14
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Hansson HH, Turner L, Møller L, Wang CW, Minja DTR, Gesase S, Mmbando B, Bygbjerg IC, Theander TG, Lusingu JPA, Alifrangis M, Lavstsen T. Haplotypes of the endothelial protein C receptor (EPCR) gene are not associated with severe malaria in Tanzania. Malar J 2015; 14:474. [PMID: 26620701 PMCID: PMC4666078 DOI: 10.1186/s12936-015-1007-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 11/20/2015] [Indexed: 12/20/2022] Open
Abstract
Background Endothelial protein C receptor (EPCR) was recently identified as a key receptor for Plasmodium falciparum erythrocyte membrane protein 1 mediating sequestration of P. falciparum-infected erythrocytes in patients suffering from severe malaria. Soluble EPCR (sEPCR) inhibits binding of P. falciparum to EPCR in vitro and increased levels of sEPCR have been associated with the H3 haplotype of the EPCR encoding PROCR gene. It has been hypothesized that elevated sEPCR levels, possibly linked to the PROCR H3 genetic variant, may confer protection against severe forms of malaria. This study determined the frequencies of PROCR haplotypes H1–4 and plasma levels of sEPCR in a Tanzanian study population to investigate a possible association with severe malaria.
Methods Study participants were children under 5 years of age admitted at the Korogwe District Hospital (N = 143), and diagnosed as having severe malaria (N = 52; including cerebral malaria N = 17), uncomplicated malaria (N = 24), or an infection other than malaria (N = 67). In addition, blood samples from 71 children living in nearby villages were included. The SNPs defining the haplotypes of PROCR gene were determined by post-PCR ligation detection reaction-fluorescent microsphere assay. Results Individuals carrying at least one H3 allele had significantly higher levels of sEPCR than individuals with no H3 alleles (P < 0.001). No difference in the frequency of H3 was found between the non-malaria patients, malaria patients or the village population (P > 0.1). Plasma levels of sEPCR differed between these three groups, with higher sEPCR levels in the village population compared to the hospitalized patients (P < 0.001) and higher levels in malaria patients compared to non-malaria patients (P = 0.001). However, no differences were found in the distribution of H3 (P = 0.2) or levels of sEPCR (P = 0.8) between patients diagnosed with severe and uncomplicated malaria. Conclusion Frequencies of SNPs determining PROCR haplotypes were in concordance with other African studies. The PROCR H3 allele was associated with higher levels of sEPCR, confirming earlier findings, however, in this Tanzanian population; neither PROCR haplotype nor level of sEPCR was associated with severe malaria, however, larger studies are needed to confirm these findings.
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Affiliation(s)
- Helle Holm Hansson
- Centre for Medical Parasitology, Department of Immunology and Microbiology, Faculty of Health and Medical Science, University of Copenhagen, Østerfarimagsgade 5, Building 22-23, 1356, Copenhagen K, Denmark. .,Department of Clinical Microbiology and Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), Blegdamsvej 9, 2100, Copenhagen Ø, Denmark.
| | - Louise Turner
- Centre for Medical Parasitology, Department of Immunology and Microbiology, Faculty of Health and Medical Science, University of Copenhagen, Østerfarimagsgade 5, Building 22-23, 1356, Copenhagen K, Denmark. .,Department of Clinical Microbiology and Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), Blegdamsvej 9, 2100, Copenhagen Ø, Denmark.
| | - Line Møller
- Centre for Medical Parasitology, Department of Immunology and Microbiology, Faculty of Health and Medical Science, University of Copenhagen, Østerfarimagsgade 5, Building 22-23, 1356, Copenhagen K, Denmark. .,Department of Clinical Microbiology and Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), Blegdamsvej 9, 2100, Copenhagen Ø, Denmark.
| | - Christian William Wang
- Centre for Medical Parasitology, Department of Immunology and Microbiology, Faculty of Health and Medical Science, University of Copenhagen, Østerfarimagsgade 5, Building 22-23, 1356, Copenhagen K, Denmark. .,Department of Clinical Microbiology and Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), Blegdamsvej 9, 2100, Copenhagen Ø, Denmark.
| | - Daniel T R Minja
- Tanga Research Centre, National Institute for Medical Research, Bombo Area, PO Box 5004, Tanga, United Republic of Tanzania.
| | - Samwel Gesase
- Tanga Research Centre, National Institute for Medical Research, Bombo Area, PO Box 5004, Tanga, United Republic of Tanzania.
| | - Bruno Mmbando
- Tanga Research Centre, National Institute for Medical Research, Bombo Area, PO Box 5004, Tanga, United Republic of Tanzania.
| | - Ib Christian Bygbjerg
- Centre for Medical Parasitology, Department of Immunology and Microbiology, Faculty of Health and Medical Science, University of Copenhagen, Østerfarimagsgade 5, Building 22-23, 1356, Copenhagen K, Denmark. .,Department of Clinical Microbiology and Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), Blegdamsvej 9, 2100, Copenhagen Ø, Denmark.
| | - Thor G Theander
- Centre for Medical Parasitology, Department of Immunology and Microbiology, Faculty of Health and Medical Science, University of Copenhagen, Østerfarimagsgade 5, Building 22-23, 1356, Copenhagen K, Denmark. .,Department of Clinical Microbiology and Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), Blegdamsvej 9, 2100, Copenhagen Ø, Denmark.
| | - John P A Lusingu
- Centre for Medical Parasitology, Department of Immunology and Microbiology, Faculty of Health and Medical Science, University of Copenhagen, Østerfarimagsgade 5, Building 22-23, 1356, Copenhagen K, Denmark. .,Tanga Research Centre, National Institute for Medical Research, Bombo Area, PO Box 5004, Tanga, United Republic of Tanzania.
| | - Michael Alifrangis
- Centre for Medical Parasitology, Department of Immunology and Microbiology, Faculty of Health and Medical Science, University of Copenhagen, Østerfarimagsgade 5, Building 22-23, 1356, Copenhagen K, Denmark. .,Department of Clinical Microbiology and Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), Blegdamsvej 9, 2100, Copenhagen Ø, Denmark.
| | - Thomas Lavstsen
- Centre for Medical Parasitology, Department of Immunology and Microbiology, Faculty of Health and Medical Science, University of Copenhagen, Østerfarimagsgade 5, Building 22-23, 1356, Copenhagen K, Denmark. .,Department of Clinical Microbiology and Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), Blegdamsvej 9, 2100, Copenhagen Ø, Denmark.
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15
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Petersen JEV, Bouwens EAM, Tamayo I, Turner L, Wang CW, Stins M, Theander TG, Hermida J, Mosnier LO, Lavstsen T. Protein C system defects inflicted by the malaria parasite protein PfEMP1 can be overcome by a soluble EPCR variant. Thromb Haemost 2015; 114:1038-48. [PMID: 26155776 DOI: 10.1160/th15-01-0018] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Accepted: 05/23/2015] [Indexed: 12/23/2022]
Abstract
The Endothelial Protein C receptor (EPCR) is essential for the anticoagulant and cytoprotective functions of the Protein C (PC) system. Selected variants of the malaria parasite protein, Plasmodium falciparum Erythrocyte Membrane Protein 1 (PfEMP1) associated with severe malaria, including cerebral malaria, specifically target EPCR on vascular endothelial cells. Here, we examine the cellular response to PfEMP1 engagement to elucidate its role in malaria pathogenesis. Binding of the CIDRα1.1 domain of PfEMP1 to EPCR obstructed activated PC (APC) binding to EPCR and induced a loss of cellular EPCR functions. CIDRα1.1 severely impaired endothelial PC activation and effectively blocked APC-mediated activation of protease-activated receptor-1 (PAR1) and associated barrier protective effects of APC on endothelial cells. A soluble EPCR variant (E86A-sEPCR) bound CIDRα1.1 with high affinity and did not interfere with (A)PC binding to cellular EPCR. E86A-sEPCR used as a decoy to capture PfEMP1, permitted normal PC activation on endothelial cells, normal barrier protective effects of APC, and greatly reduced cytoadhesion of infected erythrocytes to brain endothelial cells. These data imply important contributions of PfEMP1-induced protein C pathway defects in the pathogenesis of severe malaria. Furthermore, the E86A-sEPCR decoy provides a proof-of-principle strategy for the development of novel adjunct therapies for severe malaria.
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Affiliation(s)
- Jens E V Petersen
- Jens E. V. Petersen, Centre for Medical Parasitology, Dept. of International Health, Immunology & Microbiology, University of Copenhagen and Dept. of Infectious Diseases, Rigshospitalet, 1014 Copenhagen, Denmark, Tel.: +45 35327549, Fax: +45 35327851, E-mail:
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16
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Hviid L, Jensen ATR. PfEMP1 - A Parasite Protein Family of Key Importance in Plasmodium falciparum Malaria Immunity and Pathogenesis. ADVANCES IN PARASITOLOGY 2015; 88:51-84. [PMID: 25911365 DOI: 10.1016/bs.apar.2015.02.004] [Citation(s) in RCA: 107] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Plasmodium falciparum causes the most severe form of malaria and is responsible for essentially all malaria-related deaths. The accumulation in various tissues of erythrocytes infected by mature P. falciparum parasites can lead to circulatory disturbances and inflammation, and is thought to be a central element in the pathogenesis of the disease. It is mediated by the interaction of parasite ligands on the erythrocyte surface and a range of host receptor molecules in many organs and tissues. Among several proteins and protein families implicated in this process, the P. falciparum erythrocyte membrane protein 1 (PfEMP1) family of high-molecular weight and highly variable antigens appears to be the most prominent. In this chapter, we aim to provide a systematic overview of the current knowledge about these proteins, their structure, their function, how they are presented on the erythrocyte surface, and how the var genes encoding them are regulated. The role of PfEMP1 in the pathogenesis of malaria, PfEMP1-specific immune responses, and the prospect of PfEMP1-specific vaccination against malaria are also covered briefly.
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Affiliation(s)
- Lars Hviid
- Centre for Medical Parasitology, University of Copenhagen and Copenhagen University Hospital (Rigshospitalet), Copenhagen, Denmark
| | - Anja T R Jensen
- Centre for Medical Parasitology, University of Copenhagen and Copenhagen University Hospital (Rigshospitalet), Copenhagen, Denmark
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17
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Schuldt K, Ehmen C, Evans J, May J, Ansong D, Sievertsen J, Muntau B, Ruge G, Agbenyega T, Horstmann RD. Endothelial protein C receptor gene variants not associated with severe malaria in ghanaian children. PLoS One 2014; 9:e115770. [PMID: 25541704 PMCID: PMC4277309 DOI: 10.1371/journal.pone.0115770] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Accepted: 11/27/2014] [Indexed: 12/03/2022] Open
Abstract
Background Two recent reports have identified the Endothelial Protein C Receptor (EPCR) as a key molecule implicated in severe malaria pathology. First, it was shown that EPCR in the human microvasculature mediates sequestration of Plasmodium falciparum-infected erythrocytes. Second, microvascular thrombosis, one of the major processes causing cerebral malaria, was linked to a reduction in EPCR expression in cerebral endothelial layers. It was speculated that genetic variation affecting EPCR functionality could influence susceptibility to severe malaria phenotypes, rendering PROCR, the gene encoding EPCR, a promising candidate for an association study. Methods Here, we performed an association study including high-resolution variant discovery of rare and frequent genetic variants in the PROCR gene. The study group, which previously has proven to be a valuable tool for studying the genetics of malaria, comprised 1,905 severe malaria cases aged 1–156 months and 1,866 apparently healthy children aged 2–161 months from the Ashanti Region in Ghana, West Africa, where malaria is highly endemic. Association of genetic variation with severe malaria phenotypes was examined on the basis of single variants, reconstructed haplotypes, and rare variant analyses. Results A total of 41 genetic variants were detected in regulatory and coding regions of PROCR, 17 of which were previously unknown genetic variants. In association tests, none of the single variants, haplotypes or rare variants showed evidence for an association with severe malaria, cerebral malaria, or severe malaria anemia. Conclusion Here we present the first analysis of genetic variation in the PROCR gene in the context of severe malaria in African subjects and show that genetic variation in the PROCR gene in our study population does not influence susceptibility to major severe malaria phenotypes.
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Affiliation(s)
- Kathrin Schuldt
- Department of Molecular Medicine, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
- * E-mail:
| | - Christa Ehmen
- Department of Molecular Medicine, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Jennifer Evans
- Department of Molecular Medicine, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Juergen May
- Infectious Disease Epidemiology Group, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Daniel Ansong
- School of Medical Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Juergen Sievertsen
- Department of Molecular Medicine, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Birgit Muntau
- Department of Molecular Medicine, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Gerd Ruge
- Department of Molecular Medicine, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Tsiri Agbenyega
- School of Medical Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Rolf D. Horstmann
- Department of Molecular Medicine, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
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18
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Structural conservation despite huge sequence diversity allows EPCR binding by the PfEMP1 family implicated in severe childhood malaria. Cell Host Microbe 2014; 17:118-29. [PMID: 25482433 PMCID: PMC4297295 DOI: 10.1016/j.chom.2014.11.007] [Citation(s) in RCA: 129] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Revised: 09/27/2014] [Accepted: 10/30/2014] [Indexed: 11/20/2022]
Abstract
The PfEMP1 family of surface proteins is central for Plasmodium falciparum virulence and must retain the ability to bind to host receptors while also diversifying to aid immune evasion. The interaction between CIDRα1 domains of PfEMP1 and endothelial protein C receptor (EPCR) is associated with severe childhood malaria. We combine crystal structures of CIDRα1:EPCR complexes with analysis of 885 CIDRα1 sequences, showing that the EPCR-binding surfaces of CIDRα1 domains are conserved in shape and bonding potential, despite dramatic sequence diversity. Additionally, these domains mimic features of the natural EPCR ligand and can block this ligand interaction. Using peptides corresponding to the EPCR-binding region, antibodies can be purified from individuals in malaria-endemic regions that block EPCR binding of diverse CIDRα1 variants. This highlights the extent to which such a surface protein family can diversify while maintaining ligand-binding capacity and identifies features that should be mimicked in immunogens to prevent EPCR binding. EPCR binding is retained by PfEMP1 CIDRα1 domains despite huge sequence variation Diverse CIDRα1 domains retain structural and chemical features to bind to EPCR CIDRα1 domains mimic features of a natural ligand of EPCR and block its binding Patient sera contain neutralizing antibodies that prevent parasite binding to EPCR
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19
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Moussiliou A, Alao MJ, Denoeud-Ndam L, Tahar R, Ezimegnon S, Sagbo G, Amoussou A, Luty AJF, Deloron P, Tuikue Ndam N. High plasma levels of soluble endothelial protein C receptor are associated with increased mortality among children with cerebral malaria in Benin. J Infect Dis 2014; 211:1484-8. [PMID: 25425698 DOI: 10.1093/infdis/jiu661] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Accepted: 11/20/2014] [Indexed: 11/14/2022] Open
Abstract
Loss of endothelial protein C receptor (EPCR) occurs at the sites of Plasmodium falciparum-infected erythrocyte sequestration in patients with or who died from cerebral malaria. In children presenting with different clinical syndromes of malaria, we assessed the relationships between endogenous plasma soluble EPCR (sEPCR) levels and clinical presentation or mortality. After adjustment for age, for treatment before admission, and for a known genetic factor, sEPCR level at admission was positively associated with cerebral malaria (P = .011) and with malaria-related mortality (P = .0003). Measuring sEPCR levels at admission could provide an early biological marker of the outcome of cerebral malaria.
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Affiliation(s)
- Azizath Moussiliou
- PRES Sorbonne Paris Cité, Faculté de Pharmacie, Université Paris Descartes Institut de Recherche pour le Développement, UMR216-MERIT Université Pierre et Marie Curie, Paris, France
| | | | - Lise Denoeud-Ndam
- PRES Sorbonne Paris Cité, Faculté de Pharmacie, Université Paris Descartes Institut de Recherche pour le Développement, UMR216-MERIT
| | - Rachida Tahar
- PRES Sorbonne Paris Cité, Faculté de Pharmacie, Université Paris Descartes Institut de Recherche pour le Développement, UMR216-MERIT
| | - Sem Ezimegnon
- Centre d'Etude et de Recherche sur le paludisme associé à la Grossesse et à l'Enfance, Université d'Abomey-Calavi
| | - Gratien Sagbo
- Service de pédiatrie, Centre National Hospitalo-Universitaire
| | - Annick Amoussou
- Service de pédiatrie, Hôpital de zone de Suru-Léré, Cotonou, Bénin
| | - Adrian J F Luty
- PRES Sorbonne Paris Cité, Faculté de Pharmacie, Université Paris Descartes Institut de Recherche pour le Développement, UMR216-MERIT
| | - Philippe Deloron
- PRES Sorbonne Paris Cité, Faculté de Pharmacie, Université Paris Descartes Institut de Recherche pour le Développement, UMR216-MERIT
| | - Nicaise Tuikue Ndam
- PRES Sorbonne Paris Cité, Faculté de Pharmacie, Université Paris Descartes Institut de Recherche pour le Développement, UMR216-MERIT
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20
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Mohan Rao LV, Esmon CT, Pendurthi UR. Endothelial cell protein C receptor: a multiliganded and multifunctional receptor. Blood 2014; 124:1553-62. [PMID: 25049281 PMCID: PMC4155268 DOI: 10.1182/blood-2014-05-578328] [Citation(s) in RCA: 143] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Accepted: 07/08/2014] [Indexed: 01/10/2023] Open
Abstract
Endothelial cell protein C receptor (EPCR) was first identified and isolated as a cellular receptor for protein C on endothelial cells. EPCR plays a crucial role in the protein C anticoagulant pathway by promoting protein C activation. In the last decade, EPCR has received wide attention after it was discovered to play a key role in mediating activated protein C (APC)-induced cytoprotective effects, including antiapoptotic, anti-inflammatory, and barrier stabilization. APC elicits cytoprotective signaling through activation of protease activated receptor-1 (PAR1). Understanding how EPCR-APC induces cytoprotective effects through activation of PAR1, whose activation by thrombin is known to induce a proinflammatory response, has become a major research focus in the field. Recent studies also discovered additional ligands for EPCR, which include factor VIIa, Plasmodium falciparum erythrocyte membrane protein, and a specific variant of the T-cell receptor. These observations open unsuspected new roles for EPCR in hemostasis, malaria pathogenesis, innate immunity, and cancer. Future research on these new discoveries will undoubtedly expand our understanding of the role of EPCR in normal physiology and disease, as well as provide novel insights into mechanisms for EPCR multifunctionality. Comprehensive understanding of EPCR may lead to development of novel therapeutic modalities in treating hemophilia, inflammation, cerebral malaria, and cancer.
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Affiliation(s)
- L Vijaya Mohan Rao
- Department of Cellular and Molecular Biology, The University of Texas Health Science Center, Tyler, TX; and
| | - Charles T Esmon
- Coagulation Biology Laboratory, Oklahoma Medical Research Foundation, Oklahoma City, OK
| | - Usha R Pendurthi
- Department of Cellular and Molecular Biology, The University of Texas Health Science Center, Tyler, TX; and
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