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Joof F, Hu R, Saidi A, Seydel KB, Cohee LM, Zheng Y, Smith JD. Plasma from older children in Malawi inhibits Plasmodium falciparum binding in 3D brain microvessels. J Infect Dis 2024:jiae315. [PMID: 38875153 DOI: 10.1093/infdis/jiae315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Revised: 05/02/2024] [Accepted: 06/12/2024] [Indexed: 06/16/2024] Open
Abstract
A hallmark of cerebral malaria is sequestration of Plasmodium falciparum-infected erythrocytes (IEs) in the brain microcirculation. Antibodies contribute to malaria immunity, but it remains unclear whether functional antibodies targeting parasite-expressed ligand can block cytoadhesion in the brain. Here, we screened the plasma of older children and young adults in Malawi to characterize the antibody response against the P. falciparum-IE surface and used a bioengineered 3D human brain microvessel model incorporating variable flow dynamics to measure adhesion blocking responses. We found a strong correlation between surface antibody reactivity by flow cytometry and reduced P. falciparum-IE binding in 3D microvessels. Moreover, there was a threshold of surface antibody reactivity necessary to achieve robust inhibitory activity. Our findings provide evidence of the acquisition of adhesion blocking antibodies against cerebral binding variants in people exposed to stable P. falciparum transmission and suggest the quality of the inhibitory response can be influenced by flow dynamics.
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Affiliation(s)
- Fatou Joof
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA USA
| | - Ruoqian Hu
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Alex Saidi
- Blantyre Malaria Project, Kamuzu University of Health Sciences, Blantyre, Malawi
| | - Karl B Seydel
- Blantyre Malaria Project, Kamuzu University of Health Sciences, Blantyre, Malawi
- Department of Osteopathic Medical Specialties, College of Osteopathic Medicine, Michigan State University, East Lansing, Michigan, USA
| | - Lauren M Cohee
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Ying Zheng
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Joseph D Smith
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA USA
- Department of Pediatrics, School of Medicine, University of Washington, Seattle, WA, USA
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2
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Sharma I, Kataria P, Das J. Cerebral malaria pathogenesis: Dissecting the role of CD4 + and CD8 + T-cells as major effectors in disease pathology. Int Rev Immunol 2024:1-18. [PMID: 38618863 DOI: 10.1080/08830185.2024.2336539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Accepted: 03/24/2024] [Indexed: 04/16/2024]
Abstract
Cerebral malaria (CM) is a severe complication of Plasmodium falciparum (P. falciparum) infection, with complex pathogenesis involving multiple factors, including the host's immunological response. T lymphocytes, specifically CD4+ T helper cells and CD8+ cytotoxic T cells, are crucial in controlling parasite growth and activating cells for parasite clearance via cytokine secretion. Contrary to this, reports also suggest the pathogenic nature of T lymphocytes as they are often involved in disease progression and severity. CD8+ cytotoxic T cells migrate to the host's brain vasculature, disrupting the blood-brain barrier and causing neurological manifestations. CD4+ T helper cells on the other hand play a variety of functions as they differentiate into different subtypes which may function as pro-inflammatory or anti-inflammatory. The excessive pro-inflammatory response in CM can lead to multi-organ failure, necessitating a check mechanism to maintain immune homeostasis. This is achieved by regulatory T cells and their characteristic cytokines, which counterbalance the pro-inflammatory immune response. Maintaining a critical balance between pro and anti-inflammatory responses is crucial for determining disease outcomes in CM. A slight change in this balance may contribute to a disease severity owing to an extreme inflammatory response or unrestricted parasite growth, a potential target for designing immunotherapeutic treatment approaches. The review briefly discusses the pathogenesis of CM and various mechanisms responsible for the disruption of the blood-brain barrier. It also highlights the role of different T cell subsets during infection and emphasizes the importance of balance between pro and anti-inflammatory T cells that ultimately decides the outcome of the disease.
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Affiliation(s)
- Indu Sharma
- Academy of Scientific and Innovative Research (AcSIR), Noida, India
- Division of Immunology, National Institute of Malaria Research, Dwarka, New Delhi, India
| | - Poonam Kataria
- Academy of Scientific and Innovative Research (AcSIR), Noida, India
- Division of Immunology, National Institute of Malaria Research, Dwarka, New Delhi, India
| | - Jyoti Das
- Academy of Scientific and Innovative Research (AcSIR), Noida, India
- Division of Immunology, National Institute of Malaria Research, Dwarka, New Delhi, India
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3
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Hviid L, Jensen AR, Deitsch KW. PfEMP1 and var genes - Still of key importance in Plasmodium falciparum malaria pathogenesis and immunity. ADVANCES IN PARASITOLOGY 2024; 125:53-103. [PMID: 39095112 DOI: 10.1016/bs.apar.2024.02.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/04/2024]
Abstract
The most severe form of malaria, caused by infection with Plasmodium falciparum parasites, continues to be an important cause of human suffering and poverty. The P. falciparum erythrocyte membrane protein 1 (PfEMP1) family of clonally variant antigens, which mediates the adhesion of infected erythrocytes to the vascular endothelium in various tissues and organs, is a central component of the pathogenesis of the disease and a key target of the acquired immune response to malaria. Much new knowledge has accumulated since we published a systematic overview of the PfEMP1 family almost ten years ago. In this chapter, we therefore aim to summarize research progress since 2015 on the structure, function, regulation etc. of this key protein family of arguably the most important human parasite. Recent insights regarding PfEMP1-specific immune responses and PfEMP1-specific vaccination against malaria, as well as an outlook for the coming years are also covered.
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Affiliation(s)
- Lars Hviid
- Centre for translational Medicine and Parasitology, Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark; Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), Copenhagen, Denmark.
| | - Anja R Jensen
- Centre for translational Medicine and Parasitology, Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Kirk W Deitsch
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, NY, United States
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4
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Faloye KO, Tripathi MK, Adesida SA, Oguntimehin SA, Oyetunde YM, Adewole AH, Ogunlowo II, Idowu EA, Olayemi UI, Dosumu OD. Antimalarial potential, LC-MS secondary metabolite profiling and computational studies of Zingiber officinale. J Biomol Struct Dyn 2024; 42:2570-2585. [PMID: 37116195 DOI: 10.1080/07391102.2023.2205949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Accepted: 04/17/2023] [Indexed: 04/30/2023]
Abstract
Malaria is among the top-ranked parasitic diseases that pose a threat to the existence of the human race. This study evaluated the antimalarial effect of the rhizome of Zingiber officinale in infected mice, performed secondary metabolite profiling and detailed computational antimalarial evaluation through molecular docking, molecular dynamics (MD) simulation and density functional theory methods. The antimalarial potential of Z. officinale was performed using the in vivo chemosuppressive model; secondary metabolite profiling was carried out using liquid chromatography-mass spectrometry (LC-MS). Molecular docking was performed with Autodock Vina while the MD simulation was performed with Schrodinger desmond suite for 100 ns and DFT calculations with B3LYP (6-31G) basis set. The extract showed 64% parasitaemia suppression, with a dose-dependent increase in activity up to 200 mg/kg. The chemical profiling of the extract tentatively identified eight phytochemicals. The molecular docking studies with plasmepsin II and Plasmodium falciparum dihydrofolate reductase-thymidylate synthase (PfDHFR-TS) identified gingerenone A as the hit molecule, and MMGBSA values corroborate the binding energies obtained. The electronic parameters of gingerenone A revealed its significant antimalarial potential. The antimalarial activity elicited by the extract of Z. officinale and the bioactive chemical constituent supports its usage in ethnomedicine.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Kolade O Faloye
- Department of Chemistry, Faculty of Science, Obafemi Awolowo University, Ile-Ife, Nigeria
| | - Manish K Tripathi
- Pharmaceutical Chemistry Research Laboratory, Department of Pharmaceutical Engineering & Technology, Indian Institute of Technology (Banaras Hindu University), Varanasi, India
| | - Stephen A Adesida
- Department of Pharmacognosy, Faculty of Pharmacy, Obafemi Awolowo University, Ile-Ife, Nigeria
| | - Samuel A Oguntimehin
- Department of Pharmacognosy, Faculty of Pharmacy, University of Ibadan, Ibadan, Nigeria
| | - Yemisi M Oyetunde
- Department of Pharmacognosy, Faculty of Pharmacy, University of Ibadan, Ibadan, Nigeria
| | - Adetola H Adewole
- Department of Chemistry, University of Pretoria, Pretoria, South Africa
| | - Ifeoluwa I Ogunlowo
- Department of Pharmacognosy, Faculty of Pharmacy, Obafemi Awolowo University, Ile-Ife, Nigeria
| | - Esther A Idowu
- Department of Pharmacognosy, Faculty of Pharmacy, Obafemi Awolowo University, Ile-Ife, Nigeria
| | - Uduak I Olayemi
- Department of Pharmacognosy, Faculty of Pharmacy, Obafemi Awolowo University, Ile-Ife, Nigeria
| | - Olamide D Dosumu
- Department of Botany, Faculty of Science, Obafemi Awolowo University, Ile-Ife, Nigeria
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5
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Govindaraju G, Rajavelu A. Reading the epitranscriptome of the human malaria parasite. Biomed J 2024:100703. [PMID: 38316392 DOI: 10.1016/j.bj.2024.100703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 01/30/2024] [Accepted: 02/01/2024] [Indexed: 02/07/2024] Open
Abstract
Epigenetic machinery has emerged as a central player in gene regulation and chromatin organization in Plasmodium spp. Epigenetic modifications on histones and their role in antigenic variation in P. falciparum are widely studied. Recent discoveries on nucleic acid methylome are exciting and provide a new dimension to the apicomplexan protozoan parasite's gene regulatory process. Reports have confirmed that N6-methyl adenosine (m6A) methylation plays a crucial role in the translational plasticity of the human malaria parasite during its development in RBC. The YTH domain (YT521-B Homology) protein in P. falciparum binds to m6A epitranscriptome modifications on the mRNA and regulates protein translation. The binding of the PfYTH domain protein to the m6A-modified mRNA is mediated through a binding pocket formed by aromatic amino acids. The P. falciparum genome encodes two members of YTH domain proteins, i.e., YTH1 and YTH2, and both have distinct roles in dictating the epitranscriptome in human malaria parasites. This review highlights recent advancements in the functions and mechanisms of YTH domain protein's role in translational plasticity in the various developmental stages of the parasite.
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Affiliation(s)
- Gayathri Govindaraju
- Department of Biotechnology, Bhupat & Jyoti Mehta School of Biosciences, Indian Institute of Technology, Chennai, India
| | - Arumugam Rajavelu
- Department of Biotechnology, Bhupat & Jyoti Mehta School of Biosciences, Indian Institute of Technology, Chennai, India.
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6
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Fraering J, Salnot V, Gautier EF, Ezinmegnon S, Argy N, Peoc'h K, Manceau H, Alao J, Guillonneau F, Migot-Nabias F, Bertin GI, Kamaliddin C. Infected erythrocytes and plasma proteomics reveal a specific protein signature of severe malaria. EMBO Mol Med 2024; 16:319-333. [PMID: 38297098 PMCID: PMC10897182 DOI: 10.1038/s44321-023-00010-0] [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: 06/27/2023] [Revised: 11/18/2023] [Accepted: 11/22/2023] [Indexed: 02/02/2024] Open
Abstract
Cerebral malaria (CM), the most lethal complication of Plasmodium falciparum severe malaria (SM), remains fatal for 15-25% of affected children despite the availability of treatment. P. falciparum infects and multiplies in erythrocytes, contributing to anemia, parasite sequestration, and inflammation. An unbiased proteomic assessment of infected erythrocytes and plasma samples from 24 Beninese children was performed to study the complex mechanisms underlying CM. A significant down-regulation of proteins from the ubiquitin-proteasome pathway and an up-regulation of the erythroid precursor marker transferrin receptor protein 1 (TFRC) were associated with infected erythrocytes from CM patients. At the plasma level, the samples clustered according to clinical presentation. Significantly, increased levels of the 20S proteasome components were associated with SM. Targeted quantification assays confirmed these findings on a larger cohort (n = 340). These findings suggest that parasites causing CM preferentially infect reticulocytes or erythroblasts and alter their maturation. Importantly, the host plasma proteome serves as a specific signature of SM and presents a remarkable opportunity for developing innovative diagnostic and prognostic biomarkers.
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Affiliation(s)
- Jeremy Fraering
- UMR261 MERIT, Université Paris Cité, IRD, F-75006, Paris, France
- Plateforme Proteom'IC, Institut Cochin, Université Paris Cité, INSERM U-1016, CNRS UMR8104, Paris, France
| | - Virginie Salnot
- Plateforme Proteom'IC, Institut Cochin, Université Paris Cité, INSERM U-1016, CNRS UMR8104, Paris, France
| | - Emilie-Fleur Gautier
- Plateforme Proteom'IC, Institut Cochin, Université Paris Cité, INSERM U-1016, CNRS UMR8104, Paris, France
- Institut Imagine-INSERM U1163, Hôpital Necker, Université Paris Cité, F-75015, Paris, France
- Laboratoire d'Excellence GR-Ex, F-75015, Paris, France
| | - Sem Ezinmegnon
- Groupe de Recherche Action en Santé, Ouagadougou, Burkina Faso
| | - Nicolas Argy
- UMR261 MERIT, Université Paris Cité, IRD, F-75006, Paris, France
- Laboratoire de parasitologie, Hôpital Bichat-Claude Bernard, APHP, Paris, France
| | - Katell Peoc'h
- Laboratoire d'Excellence GR-Ex, F-75015, Paris, France
- Biochimie Métabolique et Cellulaire, Hôpital Bichat-Claude Bernard, APHP, Paris, France
- Centre de Recherche sur l'Inflammation, UFR de Médecine Xavier Bichat, Université Paris Cité, INSERM UMR1149, Paris, France
| | - Hana Manceau
- Laboratoire d'Excellence GR-Ex, F-75015, Paris, France
- Biochimie Métabolique et Cellulaire, Hôpital Bichat-Claude Bernard, APHP, Paris, France
- Département de Biochimie, Hôpital Universitaire Beaujon, APHP, Clichy, France
| | - Jules Alao
- Service de Pédiatrie, Centre Hospitalier Universitaire de la Mère et de l'Enfant-Lagune de Cotonou, Cotonou, Benin
| | - François Guillonneau
- Plateforme Proteom'IC, Institut Cochin, Université Paris Cité, INSERM U-1016, CNRS UMR8104, Paris, France
- Unité OncoProtéomique, Institut de Cancérologie de l'Ouest, F-49055, Angers, France
- Université d'Angers, Inserm UMR 1307, CNRS UMR 6075, Nantes Université, CRCI2NA, F-49000, Angers, France
| | | | - Gwladys I Bertin
- UMR261 MERIT, Université Paris Cité, IRD, F-75006, Paris, France.
| | - Claire Kamaliddin
- UMR261 MERIT, Université Paris Cité, IRD, F-75006, Paris, France.
- Cumming School of Medicine, The University of Calgary, Calgary, AB, Canada.
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7
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Evbuomwan IO, Alejolowo OO, Elebiyo TC, Nwonuma CO, Ojo OA, Edosomwan EU, Chikwendu JI, Elosiuba NV, Akulue JC, Dogunro FA, Rotimi DE, Osemwegie OO, Ojo AB, Ademowo OG, Adeyemi OS, Oluba OM. In silico modeling revealed phytomolecules derived from Cymbopogon citratus (DC.) leaf extract as promising candidates for malaria therapy. J Biomol Struct Dyn 2024; 42:101-118. [PMID: 36974933 DOI: 10.1080/07391102.2023.2192799] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Accepted: 03/10/2023] [Indexed: 03/29/2023]
Abstract
The emergence of varying levels of resistance to currently available antimalarial drugs significantly threatens global health. This factor heightens the urgency to explore bioactive compounds from natural products with a view to discovering and developing newer antimalarial drugs with novel mode of actions. Therefore, we evaluated the inhibitory effects of sixteen phytocompounds from Cymbopogon citratus leaf extract against Plasmodium falciparum drug targets such as P. falciparum circumsporozoite protein (PfCSP), P. falciparum merozoite surface protein 1 (PfMSP1) and P. falciparum erythrocyte membrane protein 1 (PfEMP1). In silico approaches including molecular docking, pharmacophore modeling and 3D-QSAR were adopted to analyze the inhibitory activity of the compounds under consideration. The molecular docking results indicated that a compound swertiajaponin from C. citratus exhibited a higher binding affinity (-7.8 kcal/mol) to PfMSP1 as against the standard artesunate-amodiaquine (-6.6 kcal/mol). Swertiajaponin also formed strong hydrogen bond interactions with LYS29, CYS30, TYR34, ASN52, GLY55 and CYS28 amino acid residues. In addition, quercetin another compound from C. citratus exhibited significant binding energies -6.8 and -8.3 kcal/mol with PfCSP and PfEMP1, respectively but slightly lower than the standard artemether-lumefantrine with binding energies of -7.4 kcal/mol against PfCSP and -8.7 kcal/mol against PfEMP1. Overall, the present study provides evidence that swertiajaponin and other phytomolecules from C. citratus have modulatory properties toward P. falciparum drug targets and thus may warrant further exploration in early drug discovery efforts against malaria. Furthermore, these findings lend credence to the folkloric use of C. citratus for malaria treatment.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Ikponmwosa Owen Evbuomwan
- SDG #03 Group - Good Health and Well-Being Research Cluster, Landmark University, Omu-Aran, Nigeria
- Department of Biochemistry, Landmark University, Omu-Aran, Nigeria
- Department of Food Science and Microbiology, Landmark University, Omu-Aran, Nigeria
| | - Omokolade Oluwaseyi Alejolowo
- SDG #03 Group - Good Health and Well-Being Research Cluster, Landmark University, Omu-Aran, Nigeria
- Department of Biochemistry, Landmark University, Omu-Aran, Nigeria
| | | | - Charles Obiora Nwonuma
- SDG #03 Group - Good Health and Well-Being Research Cluster, Landmark University, Omu-Aran, Nigeria
- Department of Biochemistry, Landmark University, Omu-Aran, Nigeria
| | - Oluwafemi Adeleke Ojo
- Phytomedicine, Molecular Toxicology and Computational Biochemistry Research Group, Department of Biochemistry, Bowen University, Iwo, Nigeria
| | - Evelyn Uwa Edosomwan
- Department of Animal and Environmental Biology, University of Benin, Benin City, Nigeria
| | | | | | | | | | - Damilare Emmanuel Rotimi
- SDG #03 Group - Good Health and Well-Being Research Cluster, Landmark University, Omu-Aran, Nigeria
- Department of Biochemistry, Landmark University, Omu-Aran, Nigeria
| | | | | | - Olusegun George Ademowo
- Department of Pharmacology and Therapeutics, Faculty of Basic Medical Sciences, University of Ibadan, Ibadan, Nigeria
- Drug Research Laboratory, Institute of Advanced Medical Research and Training (IMRAT), College of Medicine, University of Ibadan, Ibadan, Nigeria
| | - Oluyomi Stephen Adeyemi
- SDG #03 Group - Good Health and Well-Being Research Cluster, Landmark University, Omu-Aran, Nigeria
- Department of Biochemistry, Landmark University, Omu-Aran, Nigeria
- Laboratory of Sustainable Animal Environment, Graduate School of Agricultural Science, Tohoku University, Osaki, Miyagi, Japan
| | - Olarewaju Michael Oluba
- SDG #03 Group - Good Health and Well-Being Research Cluster, Landmark University, Omu-Aran, Nigeria
- Department of Biochemistry, Landmark University, Omu-Aran, Nigeria
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8
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Wassmer SC, de Koning-Ward TF, Grau GER, Pai S. Unravelling mysteries at the perivascular space: a new rationale for cerebral malaria pathogenesis. Trends Parasitol 2024; 40:28-44. [PMID: 38065791 PMCID: PMC11072469 DOI: 10.1016/j.pt.2023.11.005] [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: 10/05/2023] [Revised: 11/13/2023] [Accepted: 11/13/2023] [Indexed: 01/06/2024]
Abstract
Cerebral malaria (CM) is a severe neurological complication caused by Plasmodium falciparum parasites; it is characterized by the sequestration of infected red blood cells within the cerebral microvasculature. New findings, combined with a better understanding of the central nervous system (CNS) barriers, have provided greater insight into the players and events involved in CM, including site-specific T cell responses in the human brain. Here, we review the updated roles of innate and adaptive immune responses in CM, with a focus on the role of the perivascular macrophage-endothelium unit in antigen presentation, in the vascular and perivascular compartments. We suggest that these events may be pivotal in the development of CM.
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Affiliation(s)
- Samuel C Wassmer
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, UK.
| | - Tania F de Koning-Ward
- School of Medicine, Deakin University, Waurn Ponds, Victoria, Australia; Institute of Mental and Physical Health and Clinical Translation, Deakin University, Geelong, Victoria, Australia
| | - Georges E R Grau
- Vascular Immunology Unit, Discipline of Pathology, School of Medical Sciences, University of Sydney, Camperdown, New South Wales, Australia
| | - Saparna Pai
- Centre for Molecular Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, Queensland, Australia.
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9
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Walker IS, Rogerson SJ. Pathogenicity and virulence of malaria: Sticky problems and tricky solutions. Virulence 2023; 14:2150456. [PMID: 36419237 PMCID: PMC9815252 DOI: 10.1080/21505594.2022.2150456] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2022] [Revised: 10/18/2022] [Accepted: 10/19/2022] [Indexed: 11/25/2022] Open
Abstract
Infections with Plasmodium falciparum and Plasmodium vivax cause over 600,000 deaths each year, concentrated in Africa and in young children, but much of the world's population remain at risk of infection. In this article, we review the latest developments in the immunogenicity and pathogenesis of malaria, with a particular focus on P. falciparum, the leading malaria killer. Pathogenic factors include parasite-derived toxins and variant surface antigens on infected erythrocytes that mediate sequestration in the deep vasculature. Host response to parasite toxins and to variant antigens is an important determinant of disease severity. Understanding how parasites sequester, and how antibody to variant antigens could prevent sequestration, may lead to new approaches to treat and prevent disease. Difficulties in malaria diagnosis, drug resistance, and specific challenges of treating P. vivax pose challenges to malaria elimination, but vaccines and other preventive strategies may offer improved disease control.
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Affiliation(s)
- Isobel S Walker
- Department of Infectious Diseases, The University of Melbourne, The Doherty Institute, Melbourne, Australia
| | - Stephen J Rogerson
- Department of Infectious Diseases, The University of Melbourne, The Doherty Institute, Melbourne, Australia
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10
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Othman B, Zeef L, Szestak T, Rchiad Z, Storm J, Askonas C, Satyam R, Madkhali A, Haley M, Wagstaff S, Couper K, Pain A, Craig A. Different PfEMP1-expressing Plasmodium falciparum variants induce divergent endothelial transcriptional responses during co-culture. PLoS One 2023; 18:e0295053. [PMID: 38033133 PMCID: PMC10688957 DOI: 10.1371/journal.pone.0295053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Accepted: 11/14/2023] [Indexed: 12/02/2023] Open
Abstract
The human malaria parasite Plasmodium falciparum is responsible for the majority of mortality and morbidity caused by malaria infection and differs from other human malaria species in the degree of accumulation of parasite-infected red blood cells in the microvasculature, known as cytoadherence or sequestration. In P. falciparum, cytoadherence is mediated by a protein called PfEMP1 which, due to its exposure to the host immune system, undergoes antigenic variation resulting in the expression of different PfEMP1 variants on the infected erythrocyte membrane. These PfEMP1s contain various combinations of adhesive domains, which allow for the differential engagement of a repertoire of endothelial receptors on the host microvasculature, with specific receptor usage associated with severe disease. We used a co-culture model of cytoadherence incubating human brain microvascular endothelial cells with erythrocytes infected with two parasite lines expressing different PfEMP1s that demonstrate different binding profiles to vascular endothelium. We determined the transcriptional profile of human brain microvascular endothelial cells (HBMEC) following different incubation periods with infected erythrocytes, identifying different transcriptional profiles of pathways previously found to be involved in the pathology of severe malaria, such as inflammation, apoptosis and barrier integrity, induced by the two PfEMP1 variants.
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Affiliation(s)
- Basim Othman
- Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, United Kingdom
| | - Leo Zeef
- Faculty of Biology, Medicine and Health, The Lydia Becker Institute of Immunology and Inflammation, University of Manchester, Manchester, United Kingdom
| | - Tadge Szestak
- Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, United Kingdom
| | - Zineb Rchiad
- Pathogen Genomics Laboratory, Bioscience Program, Biological and Environmental Sciences and Engineering (BESE) Division, King Abdullah University of Science and Technology, Thuwal, KSA
| | - Janet Storm
- Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, United Kingdom
| | - Caroline Askonas
- Pathogen Genomics Laboratory, Bioscience Program, Biological and Environmental Sciences and Engineering (BESE) Division, King Abdullah University of Science and Technology, Thuwal, KSA
| | - Rohit Satyam
- Pathogen Genomics Laboratory, Bioscience Program, Biological and Environmental Sciences and Engineering (BESE) Division, King Abdullah University of Science and Technology, Thuwal, KSA
| | - Aymen Madkhali
- Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, United Kingdom
| | - Michael Haley
- Faculty of Biology, Medicine and Health, The Lydia Becker Institute of Immunology and Inflammation, University of Manchester, Manchester, United Kingdom
| | - Simon Wagstaff
- Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, United Kingdom
| | - Kevin Couper
- Faculty of Biology, Medicine and Health, The Lydia Becker Institute of Immunology and Inflammation, University of Manchester, Manchester, United Kingdom
| | - Arnab Pain
- Pathogen Genomics Laboratory, Bioscience Program, Biological and Environmental Sciences and Engineering (BESE) Division, King Abdullah University of Science and Technology, Thuwal, KSA
| | - Alister Craig
- Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, United Kingdom
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11
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Faloye KO, Tripathi MK, Fakola EG, Adepiti AO, Adesida SA, Oyeleke IO, Adebayo PA, Aregbesola AE, Famuyiwa SO, Akinyele OF. Plasmepsin II inhibitory potential of phytochemicals isolated from African antimalarial plants: a computational approach. J Biomol Struct Dyn 2023:1-16. [PMID: 37968884 DOI: 10.1080/07391102.2023.2283146] [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: 04/02/2023] [Accepted: 11/08/2023] [Indexed: 11/17/2023]
Abstract
Plamepsin II has been identified as a therapeutic target in the Plasmodium falciparum's life cycle and may lead to a drastic reduction in deaths caused by malaria worldwide. Africa flora is rich in medicinal qualities and possesses both simple and complex bioactive phytochemicals. This study utilized computational approaches like molecular docking, molecular dynamics simulation, quantum chemical calculations and ADMET to evaluate the plasmepsin II inhibitory properties of phytochemicals isolated from African antimalarial plants. Molecular docking was carried out to estimate the binding affinity of 229 phytochemicals whereby ekeberin A, dichamanetin, 10-hydroxyusambaresine, chamuvaritin and diuvaretin were selected. Further, RMSD and RMSF plots from the 100 ns simulation results showed that the screened phytochemicals were stable in the enzyme's binding pocket. The quantum chemical calculation revealed that all the phytochemicals are strong electrophiles, while ekeberin A was identified as the most stable and dichamanetin as the most reactive. Also, ADMET studies established the drug candidacy of the phytochemicals. Thus, these phytochemicals could act as good antimalarial agents after extensive in vitro and in vivo studies.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Kolade O Faloye
- Department of Chemistry, Faculty of Science, Obafemi Awolowo University, Ile-Ife, Nigeria
| | - Manish Kumar Tripathi
- Pharmaceutical Chemistry Research Laboratory, Department of Pharmaceutical Engineering & Technology, Indian Institute of Technology (Banaras Hindu University), Varanasi, India
| | - Emmanuel G Fakola
- Department of Chemistry, Faculty of Science, Obafemi Awolowo University, Ile-Ife, Nigeria
| | - Awodayo O Adepiti
- Department of Pharmacognosy, Faculty of Pharmacy, Obafemi Awolowo University, Ile-Ife, Nigeria
| | - Stephen A Adesida
- Department of Pharmacognosy, Faculty of Pharmacy, Obafemi Awolowo University, Ile-Ife, Nigeria
| | - Ibukun O Oyeleke
- Department of Pharmacognosy, Faculty of Pharmacy, Obafemi Awolowo University, Ile-Ife, Nigeria
| | - Praise A Adebayo
- Department of Pharmacognosy, Faculty of Pharmacy, Obafemi Awolowo University, Ile-Ife, Nigeria
| | - Adeola E Aregbesola
- Department of Chemistry, Faculty of Science, Obafemi Awolowo University, Ile-Ife, Nigeria
| | - Samson O Famuyiwa
- Department of Chemistry, Faculty of Science, Obafemi Awolowo University, Ile-Ife, Nigeria
| | - Olawale F Akinyele
- Department of Chemistry, Faculty of Science, Obafemi Awolowo University, Ile-Ife, Nigeria
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12
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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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13
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Meredith S, Majam V, Zheng H, Verma N, Puri A, Akue A, KuKuruga M, Oakley M, Kumar S. Protective efficacy and correlates of immunity of immunodominant recombinant Babesia microti antigens. Infect Immun 2023; 91:e0016223. [PMID: 37728332 PMCID: PMC10580920 DOI: 10.1128/iai.00162-23] [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: 04/27/2023] [Accepted: 07/13/2023] [Indexed: 09/21/2023] Open
Abstract
Babesia microti, an intraerythrocytic apicomplexan parasite, is the primary causative agent of human babesiosis and an emerging threat to public health in the United States and elsewhere. An effective vaccine against B. microti would reduce disease severity in acute babesiosis patients and shorten the parasitemic period in asymptomatic individuals, thereby minimizing the risk of transfusion-transmitted babesiosis. Here we report on immunogenicity, protective efficacy, and correlates of immunity following immunization with four immunodominant recombinantly produced B. microti antigens-Serine Reactive Antigen 1 (SERA1), Maltese Cross Form Related Protein 1 (MCFRP1), Piroplasm β-Strand Domain 1 (PiβS1), and Babesia microti Alpha Helical Cell Surface Protein 1 (BAHCS1)-delivered subcutaneously in Montanide ISA 51/CpG adjuvant in three doses to BALB/c mice. Following B. microti parasite challenge, BAHCS1 led to the highest reduction in peak parasitemia (67.8%), followed by SERA1 (44.8%) and MCFRP1 (41.9%); PiβS1 (27.6%) had minimal protective effect. All four B. microti antigens induced high ELISA total IgG and each isotype; however, antibody levels did not directly correlate with anti-parasitic activity in mice. Increased prechallenge levels of some cell populations including follicular helper T cells (TFH) and memory B cells, along with a set of six cytokines [IL-1α, IL-2, IL-3, IL-6, IL-12(p40), and G-CSF] that belong to both innate and adaptive immune responses, were generally associated with protective immunity. Our results indicate that mechanisms driving recombinant B. microti antigen-induced immunity are complex and multifactorial. We think that BAHCS1 warrants further evaluation in preclinical studies.
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Affiliation(s)
- Scott Meredith
- Laboratory of Emerging Pathogens, Division of Emerging and Transfusion Transmitted Diseases, Office of Blood Research and Review, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland, USA
| | - Victoria Majam
- Laboratory of Emerging Pathogens, Division of Emerging and Transfusion Transmitted Diseases, Office of Blood Research and Review, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland, USA
| | - Hong Zheng
- Laboratory of Emerging Pathogens, Division of Emerging and Transfusion Transmitted Diseases, Office of Blood Research and Review, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland, USA
| | - Nitin Verma
- Laboratory of Emerging Pathogens, Division of Emerging and Transfusion Transmitted Diseases, Office of Blood Research and Review, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland, USA
| | - Ankit Puri
- Laboratory of Emerging Pathogens, Division of Emerging and Transfusion Transmitted Diseases, Office of Blood Research and Review, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland, USA
| | - Adovi Akue
- Division of Bacterial, Parasitic, and Allergenic Products, Office of Vaccines Research and Review, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland, USA
| | - Mark KuKuruga
- Division of Bacterial, Parasitic, and Allergenic Products, Office of Vaccines Research and Review, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland, USA
| | - Miranda Oakley
- Laboratory of Emerging Pathogens, Division of Emerging and Transfusion Transmitted Diseases, Office of Blood Research and Review, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland, USA
| | - Sanjai Kumar
- Laboratory of Emerging Pathogens, Division of Emerging and Transfusion Transmitted Diseases, Office of Blood Research and Review, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland, USA
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14
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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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15
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Vigetti L, Tardieux I. Fostering innovation to solve the biomechanics of microbe-host interactions: Focus on the adhesive forces underlying Apicomplexa parasite biology. Biol Cell 2023; 115:e202300016. [PMID: 37227253 DOI: 10.1111/boc.202300016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 05/19/2023] [Accepted: 05/22/2023] [Indexed: 05/26/2023]
Abstract
The protozoa, Toxoplasma gondii and Plasmodium spp., are preeminent members of the Apicomplexa parasitic phylum in large part due to their public health and economic impact. Hence, they serve as model unicellular eukaryotes with which to explore the repertoire of molecular and cellular strategies that specific developmental morphotypes deploy to timely adjust to their host(s) in order to perpetuate. In particular, host tissue- and cell-invasive morphotypes termed zoites alternate extracellular and intracellular lifestyles, thereby sensing and reacting to a wealth of host-derived biomechanical cues over their partnership. In the recent years, biophysical tools especially related to real time force measurement have been introduced, teaching us how creative are these microbes to shape a unique motility system that powers fast gliding through a variety of extracellular matrices, across cellular barriers, in vascular systems or into host cells. Equally performant was this toolkit to start illuminating how parasites manipulate their hosting cell adhesive and rheological properties to their advantage. In this review, besides highlighting major discoveries along the way, we discuss the most promising development, synergy, and multimodal integration in active noninvasive force microscopy methods. These should in the near future unlock current limitations and allow capturing, from molecules to tissues, the many biomechanical and biophysical interplays over the dynamic host and microbe partnership.
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Affiliation(s)
- Luis Vigetti
- Team Biomechanics of Host-Parasite Interactions, Institute for Advanced Biosciences, CNRS UMR5309, INSERM U1209, University of Grenoble Alpes, Grenoble, France
| | - Isabelle Tardieux
- Team Biomechanics of Host-Parasite Interactions, Institute for Advanced Biosciences, CNRS UMR5309, INSERM U1209, University of Grenoble Alpes, Grenoble, France
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16
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Santos-López J, de la Paz K, Fernández FJ, Vega MC. Structural biology of complement receptors. Front Immunol 2023; 14:1239146. [PMID: 37753090 PMCID: PMC10518620 DOI: 10.3389/fimmu.2023.1239146] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Accepted: 08/16/2023] [Indexed: 09/28/2023] Open
Abstract
The complement system plays crucial roles in a wide breadth of immune and inflammatory processes and is frequently cited as an etiological or aggravating factor in many human diseases, from asthma to cancer. Complement receptors encompass at least eight proteins from four structural classes, orchestrating complement-mediated humoral and cellular effector responses and coordinating the complex cross-talk between innate and adaptive immunity. The progressive increase in understanding of the structural features of the main complement factors, activated proteolytic fragments, and their assemblies have spurred a renewed interest in deciphering their receptor complexes. In this review, we describe what is currently known about the structural biology of the complement receptors and their complexes with natural agonists and pharmacological antagonists. We highlight the fundamental concepts and the gray areas where issues and problems have been identified, including current research gaps. We seek to offer guidance into the structural biology of the complement system as structural information underlies fundamental and therapeutic research endeavors. Finally, we also indicate what we believe are potential developments in the field.
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Affiliation(s)
- Jorge Santos-López
- Centro de Investigaciones Biológicas Margarita Salas, Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
| | - Karla de la Paz
- Centro de Investigaciones Biológicas Margarita Salas, Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
- Research & Development, Abvance Biotech SL, Madrid, Spain
| | | | - M. Cristina Vega
- Centro de Investigaciones Biológicas Margarita Salas, Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
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17
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Pinheiro ADS, Kazura JW, Pinheiro AA, Schmaier AH. Is there a role for bradykinin in cerebral malaria pathogenesis? Front Cell Infect Microbiol 2023; 13:1184896. [PMID: 37637466 PMCID: PMC10448822 DOI: 10.3389/fcimb.2023.1184896] [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: 03/13/2023] [Accepted: 07/24/2023] [Indexed: 08/29/2023] Open
Abstract
Malaria is a parasitic disease of global health significance and a leading cause of death in children living in endemic regions. Although various Plasmodium species are responsible for the disease, Plasmodium falciparum infection accounts for most severe cases of the disease in humans. The mechanisms of cerebral malaria pathogenesis have been studied extensively in humans and animal malaria models; however, it is far from being fully understood. Recent discoveries indicate a potential role of bradykinin and the kallikrein kinin system in the pathogenesis of cerebral malaria. The aim of this review is to highlight how bradykinin is formed in cerebral malaria and how it may impact cerebral blood-brain barrier function. Areas of interest in this context include Plasmodium parasite enzymes that directly generate bradykinin from plasma protein precursors, cytoadhesion of P. falciparum infected red blood cells to brain endothelial cells, and endothelial cell blood-brain barrier disruption.
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Affiliation(s)
- Alessandro de Sa Pinheiro
- Department of Medicine, Hematology and Oncology, University Hospitals Cleveland Medical Center, Case Western Reserve University, Cleveland, OH, United States
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - James W. Kazura
- Center for Global Health and Diseases, Department of Pathology, Case Western Reserve University, Cleveland, OH, United States
| | - Ana Acacia Pinheiro
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Alvin H. Schmaier
- Department of Medicine, Hematology and Oncology, University Hospitals Cleveland Medical Center, Case Western Reserve University, Cleveland, OH, United States
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18
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Carmo OM, Dixon MW. VAR2CSA Ectodomain Labeling in Plasmodium falciparum Infected Red Blood Cells and Analysis via Flow Cytometry. Bio Protoc 2023; 13:e4725. [PMID: 37575395 PMCID: PMC10415195 DOI: 10.21769/bioprotoc.4725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 02/10/2023] [Accepted: 05/05/2023] [Indexed: 08/15/2023] Open
Abstract
Presentation of the variant antigen Plasmodium falciparum erythrocyte membrane protein 1 (EMP1) at the surface of infected red blood cells (RBCs) underpins the malaria parasite's pathogenicity. The transport of EMP1 to the RBC surface is facilitated by a parasite-derived trafficking system, in which over 500 parasite proteins are exported into the host cell cytoplasm. To understand how genetic ablation of selected exported proteins affects EMP1 transport, several EMP1 surface presentation assays have been developed, including: 1) trypsinization of surface-exposed EMP1 and analysis by SDS-PAGE and immunoblotting; and 2) infected RBC binding assays, to determine binding efficiency to immobilized ligand under physiological flow conditions. Here, we describe a third EMP1 surface presentation assay, where antibodies to the ectodomain of EMP1 and flow cytometry are used to quantify surface-exposed EMP1 in live cells. The advantages of this assay include higher throughput capacity and data better suited for robust quantitative analysis. This protocol can also be applied to other cellular contexts where an antibody can be developed for the ectodomain of the protein of interest.
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Affiliation(s)
- Olivia M.S. Carmo
- Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Australia
| | - Matthew W.A. Dixon
- Department of Infectious Diseases, Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Australia
- Division of Infectious Diseases and Immune Defense, Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
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19
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Gupta S. Evolution of pathogen virulence: Studying the complex interplay of pathogen interactions, virulence and transmission helps us understand how they evolve and spread. EMBO Rep 2023:e57611. [PMID: 37465987 PMCID: PMC10398641 DOI: 10.15252/embr.202357611] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Accepted: 07/05/2023] [Indexed: 07/20/2023] Open
Abstract
Navigating the intricate interplay of competitive and co-operative interactions and the complex relationship between virulence and transmission pose challenges for our understanding of how pathogens evolve and spread.
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Affiliation(s)
- Sunetra Gupta
- Department of Biology, University of Oxford, Oxford, UK
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20
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Wiser MF. Knobs, Adhesion, and Severe Falciparum Malaria. Trop Med Infect Dis 2023; 8:353. [PMID: 37505649 PMCID: PMC10385726 DOI: 10.3390/tropicalmed8070353] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 06/30/2023] [Accepted: 07/02/2023] [Indexed: 07/29/2023] Open
Abstract
Plasmodium falciparum can cause a severe disease with high mortality. A major factor contributing to the increased virulence of P. falciparum, as compared to other human malarial parasites, is the sequestration of infected erythrocytes in the capillary beds of organs and tissues. This sequestration is due to the cytoadherence of infected erythrocytes to endothelial cells. Cytoadherence is primarily mediated by a parasite protein expressed on the surface of the infected erythrocyte called P. falciparum erythrocyte membrane protein-1 (PfEMP1). PfEMP1 is embedded in electron-dense protuberances on the surface of the infected erythrocytes called knobs. These knobs are assembled on the erythrocyte membrane via exported parasite proteins, and the knobs function as focal points for the cytoadherence of infected erythrocytes to endothelial cells. PfEMP1 is a member of the var gene family, and there are approximately 60 antigenically distinct PfEMP1 alleles per parasite genome. Var gene expression exhibits allelic exclusion, with only a single allele being expressed by an individual parasite. This results in sequential waves of antigenically distinct infected erythrocytes and this antigenic variation allows the parasite to establish long-term chronic infections. A wide range of endothelial cell receptors can bind to the various PfEMP1 alleles, and thus, antigenic variation also results in a change in the cytoadherence phenotype. The cytoadherence phenotype may result in infected erythrocytes sequestering in different tissues and this difference in sequestration may explain the wide range of possible clinical manifestations associated with severe falciparum malaria.
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Affiliation(s)
- Mark F Wiser
- Department of Tropical Medicine and Infectious Disease, Tulane University School of Public Health and Tropical Medicine, 1440 Canal Street, New Orleans, LA 70112, USA
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21
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Kekani LN, Witika BA. Current advances in nanodrug delivery systems for malaria prevention and treatment. DISCOVER NANO 2023; 18:66. [PMID: 37382765 PMCID: PMC10409709 DOI: 10.1186/s11671-023-03849-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 04/13/2023] [Indexed: 06/30/2023]
Abstract
Malaria is a life-threatening, blood-borne disease with over two hundred million cases throughout the world and is more prevalent in Sub-Saharan Africa than anywhere else in the world. Over the years, several treatment agents have been developed for malaria; however, most of these active pharmaceutical ingredients exhibit poor aqueous solubility and low bioavailability and may result in drug-resistant parasites, thus increasing malaria cases and eventually, deaths. Factors such as these in therapeutics have led to a better appreciation of nanomaterials. The ability of nanomaterials to function as drug carriers with a high loading capacity and targeted drug delivery, good biocompatibility, and low toxicity renders them an appealing alternative to conventional therapy. Nanomaterials such as dendrimers and liposomes have been demonstrated to be capable of enhancing the efficacy of antimalarial drugs. This review discusses the recent development of nanomaterials and their benefits in drug delivery for the potential treatment of malaria.
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Affiliation(s)
- Linda N Kekani
- Department of Pharmaceutical Sciences, School of Pharmacy, Sefako Makgatho Health Sciences University, Pretoria, 0208, South Africa
| | - Bwalya A Witika
- Department of Pharmaceutical Sciences, School of Pharmacy, Sefako Makgatho Health Sciences University, Pretoria, 0208, South Africa.
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22
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Cannabis sativa: A look at protozoa, helminths, insect vectors, and pests. Fitoterapia 2023; 166:105467. [PMID: 36893925 DOI: 10.1016/j.fitote.2023.105467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 02/28/2023] [Accepted: 03/03/2023] [Indexed: 03/09/2023]
Abstract
Active principles extracted from plants, such as essential oils, have been commonly described in the literature as therapeutic targets for numerous pathological conditions. Cannabis sativa, which has an ancient and peculiar history, has been used for various purposes, from recreational to compounds of pharmacotherapeutic and industrial importance, such as pesticides based on this plant. It is a plant that contains approximately 500 described cannabinoid compounds and is the target of in vitro and in vivo studies at different locations. This review clarifies the role of cannabinoid compounds in parasitic infections caused by helminths and protozoa. In addition, this study briefly presented the use of C. sativa constituents in the formulation of pesticides for vector control, as the latter topic is justified by the economic burden faced by several regions where vector-borne diseases are a troubling reality. Studies involving cannabis compounds with pesticidal potential should be encouraged, especially those that evaluate their effectiveness against the different life cycles of insects, seeking to interrupt vector proliferation after egg laying. Actions aimed at the management and cultivation of plant species with ecologically correct pharmacotherapeutic and pesticide potentials are becoming urgent.
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23
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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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24
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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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Kalita E, Panda M, Rao A, Prajapati VK. Exploring the role of secretory proteins in the human infectious diseases diagnosis and therapeutics. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2023; 133:231-269. [PMID: 36707203 DOI: 10.1016/bs.apcsb.2022.08.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Secretory proteins are playing important role during the host-pathogen interaction to develop the infection or protection into the cell. Pathogens developing infectious disease to human being are taken up by host macrophages or number of immune cells, play an important role in physiological, developmental and immunological function. At the same time, infectious agents are also secreting various proteins to neutralize the resistance caused by host cells and also helping the pathogens to develop the infection. Secretory proteins (secretome) are only developed at the time of host-pathogen interaction, therefore they become very important to develop the targeted and potential therapeutic strategies. Pathogen specific secretory proteins released during interaction with host cell provide opportunity to develop point of care and rapid diagnostic kits. Proteins secreted by pathogens at the time of interaction with host cell have also been found as immunogenic in nature and numbers of vaccines have been developed to control the spread of human infectious diseases. This chapter highlights the importance of secretory proteins in the development of diagnostic and therapeutic strategies to fight against human infectious diseases.
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Affiliation(s)
- Elora Kalita
- Department of Biochemistry, School of Life Sciences, Central University of Rajasthan, Ajmer, Rajasthan, India
| | - Mamta Panda
- Department of Biochemistry, School of Life Sciences, Central University of Rajasthan, Ajmer, Rajasthan, India
| | - Abhishek Rao
- Department of Biochemistry, School of Life Sciences, Central University of Rajasthan, Ajmer, Rajasthan, India
| | - Vijay Kumar Prajapati
- Department of Biochemistry, School of Life Sciences, Central University of Rajasthan, Ajmer, Rajasthan, India.
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Jajosky RP, Wu SC, Zheng L, Jajosky AN, Jajosky PG, Josephson CD, Hollenhorst MA, Sackstein R, Cummings RD, Arthur CM, Stowell SR. ABO blood group antigens and differential glycan expression: Perspective on the evolution of common human enzyme deficiencies. iScience 2023; 26:105798. [PMID: 36691627 PMCID: PMC9860303 DOI: 10.1016/j.isci.2022.105798] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Enzymes catalyze biochemical reactions and play critical roles in human health and disease. Enzyme variants and deficiencies can lead to variable expression of glycans, which can affect physiology, influence predilection for disease, and/or directly contribute to disease pathogenesis. Although certain well-characterized enzyme deficiencies result in overt disease, some of the most common enzyme deficiencies in humans form the basis of blood groups. These carbohydrate blood groups impact fundamental areas of clinical medicine, including the risk of infection and severity of infectious disease, bleeding risk, transfusion medicine, and tissue/organ transplantation. In this review, we examine the enzymes responsible for carbohydrate-based blood group antigen biosynthesis and their expression within the human population. We also consider the evolutionary selective pressures, e.g. malaria, that may account for the variation in carbohydrate structures and the implications of this biology for human disease.
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Affiliation(s)
- Ryan Philip Jajosky
- Joint Program in Transfusion Medicine, Brigham and Women’s Hospital, Harvard Medical School, 630E New Research Building, 77 Avenue Louis Pasteur, Boston, MA 02115, USA
- Biconcavity Inc, Lilburn, GA, USA
| | - Shang-Chuen Wu
- Joint Program in Transfusion Medicine, Brigham and Women’s Hospital, Harvard Medical School, 630E New Research Building, 77 Avenue Louis Pasteur, Boston, MA 02115, USA
| | - Leon Zheng
- Joint Program in Transfusion Medicine, Brigham and Women’s Hospital, Harvard Medical School, 630E New Research Building, 77 Avenue Louis Pasteur, Boston, MA 02115, USA
| | - Audrey N. Jajosky
- University of Rochester Medical Center, Department of Pathology and Laboratory Medicine, West Henrietta, NY, USA
| | | | - Cassandra D. Josephson
- Cancer and Blood Disorders Institute and Blood Bank/Transfusion Medicine Division, Johns Hopkins All Children’s Hospital, St. Petersburg, FL, USA
- Departments of Oncology and Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Marie A. Hollenhorst
- Department of Pathology and Department of Medicine, Stanford University, Stanford, CA, USA
| | - Robert Sackstein
- Translational Glycobiology Institute, Herbert Wertheim College of Medicine, Florida International University, Miami, FL, USA
| | - Richard D. Cummings
- Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Connie M. Arthur
- Joint Program in Transfusion Medicine, Brigham and Women’s Hospital, Harvard Medical School, 630E New Research Building, 77 Avenue Louis Pasteur, Boston, MA 02115, USA
| | - Sean R. Stowell
- Joint Program in Transfusion Medicine, Brigham and Women’s Hospital, Harvard Medical School, 630E New Research Building, 77 Avenue Louis Pasteur, Boston, MA 02115, USA
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Hospital-based surveillance of severe paediatric malaria in two malaria transmission ecological zones of Burkina Faso. Malar J 2023; 22:6. [PMID: 36609299 PMCID: PMC9817371 DOI: 10.1186/s12936-022-04433-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 12/24/2022] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND In the current context of tailoring interventions to maximize impact, it is important that current data of clinical epidemiology guide public health programmes and health workers in the management of severe disease. This study aimed at describing the burden of severe malaria at hospital level in two areas with distinct malaria transmission intensity. METHODS A hospital-based surveillance was established in two regional hospitals located in two areas exposed to different malaria transmission. Data on paediatric severe malaria admissions were recorded using standardized methods from August 2017 to August 2018 with an interruption during the dry season from April to June 2018. RESULTS In total, 921 children with severe malaria cases were enrolled in the study. The mean age was 33.9 (± 1.3) and 36.8 (± 1.6) months in lower malaria transmission (LMT) and higher malaria transmission (HMT) areas (p = 0.15), respectively. The geometric mean of asexual P. falciparum density was significantly higher in the LMT area compared to the HMT area: 22,861 trophozoites/µL (95% CI 17,009.2-30,726.8) vs 11,291.9 trophozoites/µL (95% CI 8577.9-14,864.5). Among enrolled cases, coma was present in 70 (9.2%) participants. 196 patients (21.8%) presented with two or more convulsions episodes prior to admission. Severe anaemia was present in 448 children (49.2%). Other clinical features recorded included 184 (19.9%) cases of lethargy, 99 (10.7%) children with incoercible vomiting, 80 (8.9%) patients with haemoglobinuria, 43 (4.8%) children with severe hypoglycaemia, 37 (4.0%) cases where child was unable to drink/suck, 11 (1.2%) cases of patients with circulatory collapse/shock, and 8 cases (0.9%) of abnormal bleeding (epistaxis). The adjusted odds of presenting with coma, respiratory distress, haemoglobinuria, circulatory collapse/shock and hypoglycaemia were significantly higher (respectively 6.5 (95%CI 3.4-12.1); 1.8 (95%CI 1.0-3.2); 2.7 (95%CI 1.6-4.3); 5.9 (95%CI 1.3-27.9); 1.9 (95%CI 1.0-3.6)) in children living in the HMT area compared to those residing in the LMT area. Overall, forty-four children died during hospitalization (case fatality rate 5.0%) with the highest fatalities in children admitted with respiratory distress (26.0%) and those with hypoglycaemia (25.0%). CONCLUSION The study showed that children in the HMT area have a higher risk of presenting with coma, shock/dehydration, haemoglobinuria, hypoglycaemia, and respiratory distress. Case-fatality rate is higher among patients with respiratory distress or hypoglycaemia. Hospital surveillance provides a reliable and sustainable means to monitor the clinical presentation of severe malaria and tailor the training needs and resources allocation for case management.
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Chandley P, Ranjan R, Kumar S, Rohatgi S. Host-parasite interactions during Plasmodium infection: Implications for immunotherapies. Front Immunol 2023; 13:1091961. [PMID: 36685595 PMCID: PMC9845897 DOI: 10.3389/fimmu.2022.1091961] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Accepted: 12/12/2022] [Indexed: 01/05/2023] Open
Abstract
Malaria is a global infectious disease that remains a leading cause of morbidity and mortality in the developing world. Multiple environmental and host and parasite factors govern the clinical outcomes of malaria. The host immune response against the Plasmodium parasite is heterogenous and stage-specific both in the human host and mosquito vector. The Plasmodium parasite virulence is predominantly associated with its ability to evade the host's immune response. Despite the availability of drug-based therapies, Plasmodium parasites can acquire drug resistance due to high antigenic variations and allelic polymorphisms. The lack of licensed vaccines against Plasmodium infection necessitates the development of effective, safe and successful therapeutics. To design an effective vaccine, it is important to study the immune evasion strategies and stage-specific Plasmodium proteins, which are targets of the host immune response. This review provides an overview of the host immune defense mechanisms and parasite immune evasion strategies during Plasmodium infection. Furthermore, we also summarize and discuss the current progress in various anti-malarial vaccine approaches, along with antibody-based therapy involving monoclonal antibodies, and research advancements in host-directed therapy, which can together open new avenues for developing novel immunotherapies against malaria infection and transmission.
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Affiliation(s)
- Pankaj Chandley
- Department of Biosciences and Bioengineering, Indian Institute of Technology, Roorkee, India
| | - Ravikant Ranjan
- Department of Biosciences and Bioengineering, Indian Institute of Technology, Roorkee, India
| | - Sudhir Kumar
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, WA, United States
| | - Soma Rohatgi
- Department of Biosciences and Bioengineering, Indian Institute of Technology, Roorkee, India,*Correspondence: Soma Rohatgi,
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Ngulube P. Humoral Immune Responses to P. falciparum Circumsporozoite Protein (Pfcsp) Induced by the RTS, S Vaccine - Current Update. Infect Drug Resist 2023; 16:2147-2157. [PMID: 37077252 PMCID: PMC10106824 DOI: 10.2147/idr.s401247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Accepted: 03/23/2023] [Indexed: 04/21/2023] Open
Abstract
Malaria vaccines targeting the circumsporozoite protein (CSP) of the P. falciparum parasite have been overall relatively promising. RTS, S is a pre-erythrocytic recombinant protein-based malaria vaccine that targets CSP. RTS, S effectiveness shows some limited success regardless of its 58% efficacy for severe disease. P. falciparum circumsporozoite protein (Pfcsp) has stood to be the main candidate protein for most pre-erythrocytic stage vaccines. Studies on the structural and biophysical characteristics of antibodies specific to CSP (anti-CSP) are underway to achieve fine specificity with the CSP polymorphic regions. More recent studies have proposed the use of different kinds of monoclonal antibodies, the use of appropriate adjuvants, ideal vaccination dose and frequency, and improved targeting of particular epitopes for the robust production of functional antibodies and high complement-fixing activity as other potential methods for achieving long-lasting RTS, S. This review highlights recent findings regarding humoral immune responses to CSP elicited by RTS, S vaccine.
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Affiliation(s)
- Peter Ngulube
- Department of Biological Sciences, Academy of Medical Sciences, Malawi University of Science and Technology, Thyolo, Malawi
- Correspondence: Peter Ngulube, Email
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30
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Nortey LN, Anning AS, Nakotey GK, Ussif AM, Opoku YK, Osei SA, Aboagye B, Ghartey-Kwansah G. Genetics of cerebral malaria: pathogenesis, biomarkers and emerging therapeutic interventions. Cell Biosci 2022; 12:91. [PMID: 35715862 PMCID: PMC9204375 DOI: 10.1186/s13578-022-00830-6] [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: 01/27/2022] [Accepted: 06/07/2022] [Indexed: 11/10/2022] Open
Abstract
Abstract
Background
Cerebral malaria (CM) is a preeminent cause of severe disease and premature deaths in Sub-Saharan Africa, where an estimated 90% of cases occur. The key features of CM are a deep, unarousable coma that persists for longer than 1 h in patients with peripheral Plasmodium falciparum and no other explanation for encephalopathy. Significant research efforts on CM in the last few decades have focused on unravelling the molecular underpinnings of the disease pathogenesis and the identification of potential targets for therapeutic or pharmacologic intervention. These efforts have been greatly aided by the generation and study of mouse models of CM, which have provided great insights into key events of CM pathogenesis, revealed an interesting interplay of host versus parasite factors that determine the progression of malaria to severe disease and exposed possible targets for therapeutic intervention in severe disease.
Main Body
This paper reviews our current understanding of the pathogenic and immunologic factors involved in CM. We present the current view of the roles of certain gene products e.g., the var gene, ABCA-1, ICAM-1, TNF-alpha, CD-36, PfEMP-1 and G6PD, in CM pathogenesis. We also present alterations in the blood–brain barrier as a consequence of disease proliferation as well as complicated host and parasite interactions, including the T-cell immune reaction, reduced deformation of erythrocytes and cytoadherence. We further looked at recent advances in cerebral malaria treatment interventions by emphasizing on biomarkers, new diagnostic tools and emerging therapeutic options.
Conclusion
Finally, we discuss how the current understanding of some of these pathogenic and immunologic factors could inform the development of novel therapeutic interventions to fight CM.
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Ramachandran A, Sharma A. Dissecting the mechanisms of pathogenesis in cerebral malaria. PLoS Pathog 2022; 18:e1010919. [PMCID: PMC9671333 DOI: 10.1371/journal.ppat.1010919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Cerebral malaria (CM) is one of the leading causes of death due to malaria. It is characterised by coma, presence of asexual parasites in blood smear, and absence of any other reason that can cause encephalopathy. The fatality rate for CM is high, and those who survive CM often experience long-term sequelae, including cognitive and motor dysfunctions. It is unclear how parasites sequestered in the lumen of endothelial cells of the blood–brain barrier (BBB), and localised breakdown of BBB can manifest gross physiological changes across the brain. The pathological changes associated with CM are mainly due to the dysregulation of inflammatory and coagulation pathways. Other factors like host and parasite genetics, transmission intensity, and the host’s immune status are likely to play a role in the development and progression of CM. This work focuses on the pathological mechanisms underlying CM. Insights from humans, mice, and in vitro studies have been summarised to present a cohesive understanding of molecular mechanisms involved in CM pathology.
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Affiliation(s)
- Arathy Ramachandran
- Molecular Medicine Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
| | - Amit Sharma
- Molecular Medicine Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
- * E-mail:
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32
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Rational designing of peptide-ligand conjugates-based immunotherapy for the treatment of complicated malaria. Life Sci 2022; 311:121121. [DOI: 10.1016/j.lfs.2022.121121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2022] [Revised: 10/19/2022] [Accepted: 10/20/2022] [Indexed: 11/05/2022]
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Leukocyte and IgM Responses to Immunization with the CIDR1α-PfEMP1 Recombinant Protein in the Wistar Rat. Trop Med Infect Dis 2022; 7:tropicalmed7090222. [PMID: 36136633 PMCID: PMC9504645 DOI: 10.3390/tropicalmed7090222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Revised: 08/29/2022] [Accepted: 08/29/2022] [Indexed: 11/25/2022] Open
Abstract
The malaria vaccine is an important strategy for the global malaria elimination program, but the complexity of the Plasmodium antigen is a major hurdle in malaria vaccine development. The cysteine-rich interdomain region 1α (CIDR1α) of Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) is crucial in malaria pathogenesis, making it a vaccine candidate. This study investigated the leukocyte and IgM response generated after administering a CIDR1α-PfEMP1 recombinant protein injection in Wistar rats. The rats were divided into a control group, who received a physiological saline solution (PSS), and a treatment group, who were subcutaneously injected with 150 µg of purified CIDR1α-PfEMP1 protein three times at the 3-week interval. Blood samples were collected every week after each injection. The number of leukocytes were counted using a Neubauer chamber, and the IgM concentration was determined using an enzyme-linked immunosorbent assay (ELISA). Data were analyzed using an independent, paired-T test, a Mann−Whitney test, and a Wilcoxon test, based on the distribution of the data. The total number of leukocytes notably increased on day 29 (p < 0.05). The percentage of neutrophils decreased, especially on day 8 (p < 0.05), whereas the percentages of monocytes and lymphocytes increased, primarily on day 14 (p < 0.05). The IgM concentration increased on day 14 (p < 0.05). In conclusion, the CIDR1α-PfEMP1 recombinant protein may induce leukocyte and IgM responses, making it a potential malaria vaccine candidate.
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Oosterhoff JJ, Larsen MD, van der Schoot CE, Vidarsson G. Afucosylated IgG responses in humans - structural clues to the regulation of humoral immunity. Trends Immunol 2022; 43:800-814. [PMID: 36008258 PMCID: PMC9395167 DOI: 10.1016/j.it.2022.08.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 08/02/2022] [Accepted: 08/05/2022] [Indexed: 11/30/2022]
Abstract
Healthy immune responses require efficient protection without excessive inflammation. Recent discoveries on the degree of fucosylation of a human N-linked glycan at a conserved site in the immunoglobulin IgG-Fc domain might add an additional regulatory layer to adaptive humoral immunity. Specifically, afucosylation of IgG-Fc enhances the interaction of IgG with FcγRIII and thereby its activity. Although plasma IgG is generally fucosylated, afucosylated IgG is raised in responses to enveloped viruses and Plasmodium falciparum proteins expressed on infected erythrocytes, as well as during alloimmune responses. Moreover, while afucosylation can exacerbate some infectious diseases (e.g., COVID-19), it also correlates with traits of protective immunity against malaria and HIV-1. Herein we discuss the implications of IgG afucosylation for health and disease, as well as for vaccination.
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Affiliation(s)
- Janita J Oosterhoff
- Immunoglobulin Research Laboratory, Department of Experimental Immunohematology, Sanquin Research, Amsterdam, The Netherlands; Department of Biomolecular Mass Spectrometry and Proteomics, Utrecht Institute for Pharmaceutical Sciences and Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht, The Netherlands
| | - Mads Delbo Larsen
- Immunoglobulin Research Laboratory, Department of Experimental Immunohematology, Sanquin Research, Amsterdam, The Netherlands; Department of Biomolecular Mass Spectrometry and Proteomics, Utrecht Institute for Pharmaceutical Sciences and Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht, The Netherlands
| | - C Ellen van der Schoot
- Immunoglobulin Research Laboratory, Department of Experimental Immunohematology, Sanquin Research, Amsterdam, The Netherlands; Landsteiner Laboratory, Amsterdam University Medical Center (UMC), University of Amsterdam, Amsterdam, The Netherlands
| | - Gestur Vidarsson
- Immunoglobulin Research Laboratory, Department of Experimental Immunohematology, Sanquin Research, Amsterdam, The Netherlands; Department of Biomolecular Mass Spectrometry and Proteomics, Utrecht Institute for Pharmaceutical Sciences and Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht, The Netherlands.
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Wang X, Chen J, Zheng J. The state of the art of extracellular vesicle research in protozoan infection. Front Genet 2022; 13:941561. [PMID: 36035188 PMCID: PMC9417467 DOI: 10.3389/fgene.2022.941561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Accepted: 07/25/2022] [Indexed: 11/25/2022] Open
Abstract
Protozoan diseases seriously affect the health of human beings, livestock and poultry and lead to high economic and medical costs. Extracellular vesicles (EVs) are membranous structures formed through biological processes that play important roles in immune regulation. Studies have shown that parasites transmit information to hosts through EVs to modulate host immune responses. The major roles played by EVs released from parasites involve facilitating parasitization of the host. In this review, we discuss relevant recently obtained data on EVs secreted by different kinds of protozoa, including their molecular mechanisms, and discuss the roles played by EVs in the occurrence and development of parasitic diseases.
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Affiliation(s)
- Xinlei Wang
- Department of Clinical Laboratory, The Second Hospital of Jilin University, Jilin University, Changchun, China
| | - Jie Chen
- Institute of Theoretical Chemistry, Jilin University, Changchun, China
| | - Jingtong Zheng
- Department of Pathogenobiology, College of Basic Medical Sciences, Jilin University, Changchun, China
- *Correspondence: Jingtong Zheng,
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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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Song X, Wei W, Cheng W, Zhu H, Wang W, Dong H, Li J. Cerebral malaria induced by plasmodium falciparum: clinical features, pathogenesis, diagnosis, and treatment. Front Cell Infect Microbiol 2022; 12:939532. [PMID: 35959375 PMCID: PMC9359465 DOI: 10.3389/fcimb.2022.939532] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Accepted: 06/28/2022] [Indexed: 11/13/2022] Open
Abstract
Cerebral malaria (CM) caused by Plasmodium falciparum is a fatal neurological complication of malaria, resulting in coma and death, and even survivors may suffer long-term neurological sequelae. In sub-Saharan Africa, CM occurs mainly in children under five years of age. Although intravenous artesunate is considered the preferred treatment for CM, the clinical efficacy is still far from satisfactory. The neurological damage induced by CM is irreversible and lethal, and it is therefore of great significance to unravel the exact etiology of CM, which may be beneficial for the effective management of this severe disease. Here, we review the clinical characteristics, pathogenesis, diagnosis, and clinical therapy of CM, with the aim of providing insights into the development of novel tools for improved CM treatments.
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Affiliation(s)
- Xiaonan Song
- School of Basic Medical Sciences, Hubei University of Medicine, Shiyan, China
| | - Wei Wei
- Beijing School of Chemistry and Bioengineering, University of Science and Technology Beijing, Beijing, China
| | - Weijia Cheng
- School of Basic Medical Sciences, Hubei University of Medicine, Shiyan, China
| | - Huiyin Zhu
- School of Basic Medical Sciences, Hubei University of Medicine, Shiyan, China
| | - Wei Wang
- Key Laboratory of National Health Commission on Technology for Parasitic Diseases Prevention and Control, Jiangsu Provincial Key Laboratory on Parasites and Vector Control Technology, Jiangsu Institute of Parasitic Diseases, Wuxi, China
- *Correspondence: Wei Wang, ; Haifeng Dong, ; Jian Li,
| | - Haifeng Dong
- Guangdong Key Laboratory for Genome Stability and Human Disease Prevention, Department of Biochemistry and Molecular Biology, School of Medicine, Shenzhen University, Shenzhen, China
- *Correspondence: Wei Wang, ; Haifeng Dong, ; Jian Li,
| | - Jian Li
- School of Basic Medical Sciences, Hubei University of Medicine, Shiyan, China
- *Correspondence: Wei Wang, ; Haifeng Dong, ; Jian Li,
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Sakoguchi A, Arase H. Mechanisms for Host Immune Evasion Mediated by Plasmodium falciparum-Infected Erythrocyte Surface Antigens. Front Immunol 2022; 13:901864. [PMID: 35784341 PMCID: PMC9240312 DOI: 10.3389/fimmu.2022.901864] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 05/10/2022] [Indexed: 12/20/2022] Open
Abstract
Plasmodium falciparum infection causes the most severe form of malaria. It has been hypothesized that P. falciparum directly suppresses host immune responses because sufficient acquired immunity is often not induced even by repeated P. falciparum infections in malaria-endemic areas. It is known that many kinds of P. falciparum-derived proteins are expressed on the surface of P. falciparum-infected erythrocytes (IEs), and these proteins have long been thought to be a key to the elucidation of the host immune evasion mechanisms. Our recent studies have revealed that the P. falciparum-derived erythrocyte surface antigen, RIFIN, the largest multiple gene family protein in the P. falciparum genome, suppresses host immune cell activation through direct interaction with human inhibitory immune receptors. In this review, we will discuss the molecular mechanisms for host immune evasion by P. falciparum-infected erythrocyte surface antigens. In addition, we will discuss the recently identified host immune response to P. falciparum using specialized antibodies that target host-P. falciparum-derived molecule interactions.
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Affiliation(s)
- Akihito Sakoguchi
- Department of Molecular Protozoology, Research Institute for Microbial Diseases, Osaka University, Suita, Japan
| | - Hisashi Arase
- Department of Immunochemistry, Research Institute for Microbial Diseases, Osaka University, Suita, Japan
- Laboratory of Immunochemistry, WPI Immunology Frontier Research Center, Osaka University, Suita, Japan
- Center for Infectious Disease Education and Research, Osaka University, Suita, Japan
- *Correspondence: Hisashi Arase,
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Rehn T, Lubiana P, Nguyen THT, Pansegrau E, Schmitt M, Roth LK, Brehmer J, Roeder T, Cadar D, Metwally NG, Bruchhaus I. Ectopic Expression of Plasmodium vivax vir Genes in P. falciparum Affects Cytoadhesion via Increased Expression of Specific var Genes. Microorganisms 2022; 10:microorganisms10061183. [PMID: 35744701 PMCID: PMC9230084 DOI: 10.3390/microorganisms10061183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 06/01/2022] [Accepted: 06/07/2022] [Indexed: 11/16/2022] Open
Abstract
Plasmodium falciparum-infected erythrocytes (PfIEs) adhere to endothelial cell receptors (ECRs) of blood vessels mainly via PfEMP1 proteins to escape elimination via the spleen. Evidence suggests that P. vivax-infected reticulocytes (PvIRs) also bind to ECRs, presumably enabled by VIR proteins, as shown by inhibition experiments and studies with transgenic P. falciparum expressing vir genes. To test this hypothesis, our study investigated the involvement of VIR proteins in cytoadhesion using vir gene-expressing P. falciparum transfectants. Those VIR proteins with a putative transmembrane domain were present in Maurer's clefts, and some were also present in the erythrocyte membrane. The VIR protein without a transmembrane domain (PVX_050690) was not exported. Five of the transgenic P. falciparum cell lines, including the one expressing PVX_050690, showed binding to CD36. We observed highly increased expression of specific var genes encoding PfEMP1s in all CD36-binding transfectants. These results suggest that ectopic vir expression regulates var expression through a yet unknown mechanism. In conclusion, the observed cytoadhesion of P. falciparum expressing vir genes depended on PfEMP1s, making this experimental unsuitable for characterizing VIR proteins.
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Affiliation(s)
- Torben Rehn
- Bernhard Nocht Institute for Tropical Medicine, 20359 Hamburg, Germany; (T.R.); (P.L.); (T.H.T.N.); (E.P.); (M.S.); (L.K.R.); (J.B.); (D.C.); (N.G.M.)
| | - Pedro Lubiana
- Bernhard Nocht Institute for Tropical Medicine, 20359 Hamburg, Germany; (T.R.); (P.L.); (T.H.T.N.); (E.P.); (M.S.); (L.K.R.); (J.B.); (D.C.); (N.G.M.)
| | - Thi Huyen Trang Nguyen
- Bernhard Nocht Institute for Tropical Medicine, 20359 Hamburg, Germany; (T.R.); (P.L.); (T.H.T.N.); (E.P.); (M.S.); (L.K.R.); (J.B.); (D.C.); (N.G.M.)
| | - Eva Pansegrau
- Bernhard Nocht Institute for Tropical Medicine, 20359 Hamburg, Germany; (T.R.); (P.L.); (T.H.T.N.); (E.P.); (M.S.); (L.K.R.); (J.B.); (D.C.); (N.G.M.)
| | - Marius Schmitt
- Bernhard Nocht Institute for Tropical Medicine, 20359 Hamburg, Germany; (T.R.); (P.L.); (T.H.T.N.); (E.P.); (M.S.); (L.K.R.); (J.B.); (D.C.); (N.G.M.)
| | - Lisa Katharina Roth
- Bernhard Nocht Institute for Tropical Medicine, 20359 Hamburg, Germany; (T.R.); (P.L.); (T.H.T.N.); (E.P.); (M.S.); (L.K.R.); (J.B.); (D.C.); (N.G.M.)
| | - Jana Brehmer
- Bernhard Nocht Institute for Tropical Medicine, 20359 Hamburg, Germany; (T.R.); (P.L.); (T.H.T.N.); (E.P.); (M.S.); (L.K.R.); (J.B.); (D.C.); (N.G.M.)
| | - Thomas Roeder
- Molecular Physiology Department, Zoological Institute, Christian-Albrechts University Kiel, 24118 Kiel, Germany;
- Airway Research Center North (ARCN), German Center for Lung Research (DZL), 24118 Kiel, Germany
| | - Dániel Cadar
- Bernhard Nocht Institute for Tropical Medicine, 20359 Hamburg, Germany; (T.R.); (P.L.); (T.H.T.N.); (E.P.); (M.S.); (L.K.R.); (J.B.); (D.C.); (N.G.M.)
| | - Nahla Galal Metwally
- Bernhard Nocht Institute for Tropical Medicine, 20359 Hamburg, Germany; (T.R.); (P.L.); (T.H.T.N.); (E.P.); (M.S.); (L.K.R.); (J.B.); (D.C.); (N.G.M.)
| | - Iris Bruchhaus
- Bernhard Nocht Institute for Tropical Medicine, 20359 Hamburg, Germany; (T.R.); (P.L.); (T.H.T.N.); (E.P.); (M.S.); (L.K.R.); (J.B.); (D.C.); (N.G.M.)
- Department of Biology, University of Hamburg, 22601 Hamburg, Germany
- Correspondence:
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Oresegun DR, Thorpe P, Benavente ED, Campino S, Muh F, Moon RW, Clark TG, Cox-Singh J. De Novo Assembly of Plasmodium knowlesi Genomes From Clinical Samples Explains the Counterintuitive Intrachromosomal Organization of Variant SICAvar and kir Multiple Gene Family Members. Front Genet 2022; 13:855052. [PMID: 35677565 PMCID: PMC9169567 DOI: 10.3389/fgene.2022.855052] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 04/15/2022] [Indexed: 12/31/2022] Open
Abstract
Plasmodium knowlesi, a malaria parasite of Old World macaque monkeys, is used extensively to model Plasmodium biology. Recently, P. knowlesi was found in the human population of Southeast Asia, particularly Malaysia. P. knowlesi causes uncomplicated to severe and fatal malaria in the human host with features in common with the more prevalent and virulent malaria caused by Plasmodium falciparum. As such, P. knowlesi presents a unique opportunity to develop experimental translational model systems for malaria pathophysiology informed by clinical data from same-species human infections. Experimental lines of P. knowlesi represent well-characterized genetically stable parasites, and to maximize their utility as a backdrop for understanding malaria pathophysiology, genetically diverse contemporary clinical isolates, essentially wild-type, require comparable characterization. The Oxford Nanopore PCR-free long-read sequencing platform was used to sequence and de novo assemble P. knowlesi genomes from frozen clinical samples. The sequencing platform and assembly pipelines were designed to facilitate capturing data and describing, for the first time, P. knowlesi schizont-infected cell agglutination (SICA) var and Knowlesi-Interspersed Repeats (kir) multiple gene families in parasites acquired from nature. The SICAvar gene family members code for antigenically variant proteins analogous to the virulence-associated P. falciparum erythrocyte membrane protein (PfEMP1) multiple var gene family. Evidence presented here suggests that the SICAvar family members have arisen through a process of gene duplication, selection pressure, and variation. Highly evolving genes including PfEMP1family members tend to be restricted to relatively unstable sub-telomeric regions that drive change with core genes protected in genetically stable intrachromosomal locations. The comparable SICAvar and kir gene family members are counter-intuitively located across chromosomes. Here, we demonstrate that, in contrast to conserved core genes, SICAvar and kir genes occupy otherwise gene-sparse chromosomal locations that accommodate rapid evolution and change. The novel methods presented here offer the malaria research community not only new tools to generate comprehensive genome sequence data from small clinical samples but also new insight into the complexity of clinically important real-world parasites.
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Affiliation(s)
- Damilola R. Oresegun
- Division of Infection and Global Health, School of Medicine, University of St Andrews, Scotland, United Kingdom
| | - Peter Thorpe
- Division of Infection and Global Health, School of Medicine, University of St Andrews, Scotland, United Kingdom
| | - Ernest Diez Benavente
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Susana Campino
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Fauzi Muh
- Division of Infection and Global Health, School of Medicine, University of St Andrews, Scotland, United Kingdom
| | - Robert William Moon
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Taane Gregory Clark
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
- Faculty of Epidemiology and Population Health, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Janet Cox-Singh
- Division of Infection and Global Health, School of Medicine, University of St Andrews, Scotland, United Kingdom
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IL-6 dependent expansion of inflammatory MDSCs (CD11b+ Gr-1+) promote Th-17 mediated immune response during experimental cerebral malaria. Cytokine 2022; 155:155910. [PMID: 35594680 DOI: 10.1016/j.cyto.2022.155910] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 05/03/2022] [Accepted: 05/05/2022] [Indexed: 12/18/2022]
Abstract
Myeloid derived suppressor cells (MDSCs) are a group of heterogeneous cell populations that can suppress T cell responses. Various aspects of MDSCs in regulating immune responses in several cancer and infectious diseases have been reported till date. But the role and regulation of MDSCs have not been systematically studied in the context of malaria. This study depicts the phenotypic and functional characteristics of splenic MDSCs and how they regulate Th-17 mediated immune response during Experimental Cerebral Malaria (ECM). Flow cytometric analysis reveals that MDSCs in the spleen and bone marrow expand at 8 dpi during ECM. Among subtypes of MDSCs, PMN-MDSCs show significant expansion in the spleen but M-MDSCs remain unaltered. Functional analysis of sorted MDSCs from spleens of Plasmodium berghei ANKA (PbA) infected mice shows suppressive nature of these cells and high production of Nitric oxide (NO). Besides, MDSCs were also found to express various inflammatory markers during ECM suggesting the M1 type phenotype of these cells. In-vivo depletion of MDSCs by the use of Anti Gr-1 increases mice survival but doesn't significantly alter the parasitemia. Previously, it has been reported that Treg/Th-17 balance in the spleen is skewed towards Th-17 during ECM. Depletion of MDSCs was found to regulate Th-17 percentages to homeostatic levels and subvert various inflammatory changes in the spleen. Among different factors, IL-6 was found to play an important role in the expansion of MDSCs and expression of inflammatory markers on MDSCs in a STAT3-dependent manner. These findings provide a unique insight into the role of IL-6 in the expansion of the MDSC population which causes inflammatory changes and increased Th-17 responses during ECM.
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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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43
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Simwela NV, Waters AP. Current status of experimental models for the study of malaria. Parasitology 2022; 149:1-22. [PMID: 35357277 PMCID: PMC9378029 DOI: 10.1017/s0031182021002134] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 12/07/2021] [Accepted: 12/08/2021] [Indexed: 01/09/2023]
Abstract
Infection by malaria parasites (Plasmodium spp.) remains one of the leading causes of morbidity and mortality, especially in tropical regions of the world. Despite the availability of malaria control tools such as integrated vector management and effective therapeutics, these measures have been continuously undermined by the emergence of vector resistance to insecticides or parasite resistance to frontline antimalarial drugs. Whilst the recent pilot implementation of the RTS,S malaria vaccine is indeed a remarkable feat, highly effective vaccines against malaria remain elusive. The barriers to effective vaccines result from the complexity of both the malaria parasite lifecycle and the parasite as an organism itself with consequent major gaps in our understanding of their biology. Historically and due to the practical and ethical difficulties of working with human malaria infections, research into malaria parasite biology has been extensively facilitated by animal models. Animals have been used to study disease pathogenesis, host immune responses and their (dys)regulation and further disease processes such as transmission. Moreover, animal models remain at the forefront of pre-clinical evaluations of antimalarial drugs (drug efficacy, mode of action, mode of resistance) and vaccines. In this review, we discuss commonly used animal models of malaria, the parasite species used and their advantages and limitations which hinder their extrapolation to actual human disease. We also place into this context the most recent developments such as organoid technologies and humanized mice.
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Affiliation(s)
- Nelson V. Simwela
- Institute of Infection, Immunity & Inflammation, Wellcome Centre for Integrative Parasitology, University of Glasgow, Glasgow, UK
| | - Andrew P. Waters
- Institute of Infection, Immunity & Inflammation, Wellcome Centre for Integrative Parasitology, University of Glasgow, Glasgow, UK
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Identifying Targets of Protective Antibodies against Severe Malaria in Papua, Indonesia, Using Locally Expressed Domains of Plasmodium falciparum Erythrocyte Membrane Protein 1. Infect Immun 2022; 90:e0043521. [PMID: 34871039 PMCID: PMC8853675 DOI: 10.1128/iai.00435-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1), a diverse family of multidomain proteins expressed on the surface of malaria-infected erythrocytes, is an important target of protective immunity against malaria. Our group recently studied transcription of the var genes encoding PfEMP1 in individuals from Papua, Indonesia, with severe or uncomplicated malaria. We cloned and expressed domains from 32 PfEMP1s, including 22 that were upregulated in severe malaria and 10 that were upregulated in uncomplicated malaria, using a wheat germ cell-free expression system. We used Luminex technology to measure IgG antibodies to these 32 domains and control proteins in 63 individuals (11 children). At presentation to hospital, levels of antibodies to PfEMP1 domains were either higher in uncomplicated malaria or were not significantly different between groups. Using principal component analysis, antibodies to 3 of 32 domains were highly discriminatory between groups. These included two domains upregulated in severe malaria, a DBLβ13 domain and a CIDRα1.6 domain (which has been previously implicated in severe malaria pathogenesis), and a DBLδ domain that was upregulated in uncomplicated malaria. Antibody to control non-PfEMP1 antigens did not differ with disease severity. Antibodies to PfEMP1 domains differ with malaria severity. Lack of antibodies to locally expressed PfEMP1 types, including both domains previously associated with severe malaria and newly identified targets, may in part explain malaria severity in Papuan adults.
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Wahl I, Wardemann H. How to induce protective humoral immunity against Plasmodium falciparum circumsporozoite protein. J Exp Med 2022; 219:212951. [PMID: 35006242 PMCID: PMC8754000 DOI: 10.1084/jem.20201313] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 12/03/2021] [Accepted: 12/17/2021] [Indexed: 12/23/2022] Open
Abstract
The induction of protective humoral immune responses against sporozoite surface proteins of the human parasite Plasmodium falciparum (Pf) is a prime goal in the development of a preerythrocytic malaria vaccine. The most promising antibody target is circumsporozoite protein (CSP). Although PfCSP induces strong humoral immune responses upon vaccination, vaccine efficacy is overall limited and not durable. Here, we review recent efforts to gain a better molecular and cellular understanding of anti-PfCSP B cell responses in humans and discuss ways to overcome limitations in the induction of stable titers of high-affinity antibodies that might help to increase vaccine efficacy and promote long-lived protection.
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Affiliation(s)
- Ilka Wahl
- B Cell Immunology, German Cancer Research Center, Heidelberg, Germany
| | - Hedda Wardemann
- B Cell Immunology, German Cancer Research Center, Heidelberg, Germany
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Voinson M, Nunn CL, Goldberg A. Primate malarias as a model for cross-species parasite transmission. eLife 2022; 11:e69628. [PMID: 35086643 PMCID: PMC8798051 DOI: 10.7554/elife.69628] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 01/14/2022] [Indexed: 12/16/2022] Open
Abstract
Parasites regularly switch into new host species, representing a disease burden and conservation risk to the hosts. The distribution of these parasites also gives insight into characteristics of ecological networks and genetic mechanisms of host-parasite interactions. Some parasites are shared across many species, whereas others tend to be restricted to hosts from a single species. Understanding the mechanisms producing this distribution of host specificity can enable more effective interventions and potentially identify genetic targets for vaccines or therapies. As ecological connections between human and local animal populations increase, the risk to human and wildlife health from novel parasites also increases. Which of these parasites will fizzle out and which have the potential to become widespread in humans? We consider the case of primate malarias, caused by Plasmodium parasites, to investigate the interacting ecological and evolutionary mechanisms that put human and nonhuman primates at risk for infection. Plasmodium host switching from nonhuman primates to humans led to ancient introductions of the most common malaria-causing agents in humans today, and new parasite switching is a growing threat, especially in Asia and South America. Based on a wild host-Plasmodium occurrence database, we highlight geographic areas of concern and potential areas to target further sampling. We also discuss methodological developments that will facilitate clinical and field-based interventions to improve human and wildlife health based on this eco-evolutionary perspective.
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Affiliation(s)
- Marina Voinson
- Department of Evolutionary Anthropology, Duke UniversityDurhamUnited States
| | - Charles L Nunn
- Department of Evolutionary Anthropology, Duke UniversityDurhamUnited States
- Duke Global Health, Duke UniversityDurhamUnited States
| | - Amy Goldberg
- Department of Evolutionary Anthropology, Duke UniversityDurhamUnited States
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Mackenzie G, Jensen RW, Lavstsen T, Otto TD. Varia: a tool for prediction, analysis and visualisation of variable genes. BMC Bioinformatics 2022; 23:52. [PMID: 35073845 PMCID: PMC8785495 DOI: 10.1186/s12859-022-04573-6] [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: 03/12/2021] [Accepted: 01/10/2022] [Indexed: 11/10/2022] Open
Abstract
Background Parasites use polymorphic gene families to evade the immune system or interact with the host. Assessing the diversity and expression of such gene families in pathogens can inform on the repertoire or host interaction phenotypes of clinical relevance. However, obtaining the sequences and quantifying their expression is a challenge. In Plasmodium falciparum, the highly polymorphic var genes encode the major virulence protein, PfEMP1, which bind a range of human receptors through varying combinations of DBL and CIDR domains. Here we present a tool, Varia, to predict near full-length gene sequences and domain compositions of query genes from database genes sharing short sequence tags. Varia generates output through two complementary pipelines. Varia_VIP returns all putative gene sequences and domain compositions of the query gene from any partial sequence provided, thereby enabling experimental validation of specific genes of interest and detailed assessment of their putative domain structure. Varia_GEM accommodates rapid profiling of var gene expression in complex patient samples from DBLα expression sequence tags (EST), by computing a sample overall transcript profile stratified by PfEMP1 domain types. Results Varia_VIP was tested querying sequence tags from all DBL domain types using different search criteria. On average 92% of query tags had one or more 99% identical database hits, resulting in the full-length query gene sequence being identified (> 99% identical DNA > 80% of query gene) among the five most prominent database hits, for ~ 33% of the query genes. Optimized Varia_GEM settings allowed correct prediction of > 90% of domains placed among the four most N-terminal domains, including the DBLα domain, and > 70% of C-terminal domains. With this accuracy, N-terminal domains could be predicted for > 80% of queries, whereas prediction rates of C-terminal domains dropped with the distance from the DBLα from 70 to 40%. Conclusion Prediction of var sequence and domain composition is possible from short sequence tags. Varia can be used to guide experimental validation of PfEMP1 sequences of interest and conduct high-throughput analysis of var type expression in patient samples. Supplementary Information The online version contains supplementary material available at 10.1186/s12859-022-04573-6.
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Kimingi HW, Kinyua AW, Achieng NA, Wambui KM, Mwangi S, Nguti R, Kivisi CA, Jensen ATR, Bejon P, Kapulu MC, Abdi AI, Kinyanjui SM. Breadth of Antibodies to Plasmodium falciparum Variant Surface Antigens Is Associated With Immunity in a Controlled Human Malaria Infection Study. Front Immunol 2022; 13:894770. [PMID: 35711446 PMCID: PMC9195513 DOI: 10.3389/fimmu.2022.894770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2022] [Accepted: 04/27/2022] [Indexed: 11/05/2022] Open
Abstract
Background Plasmodium falciparum variant surface antigens (VSAs) contribute to malaria pathogenesis by mediating cytoadhesion of infected red blood cells to the microvasculature endothelium. In this study, we investigated the association between anti-VSA antibodies and clinical outcome in a controlled human malaria infection (CHMI) study. Method We used flow cytometry and ELISA to measure levels of IgG antibodies to VSAs of five heterologous and one homologous P. falciparum parasite isolates, and to two PfEMP1 DBLβ domains in blood samples collected a day before the challenge and 14 days after infection. We also measured the ability of an individual's plasma to inhibit the interaction between PfEMP1 and ICAM1 using competition ELISA. We then assessed the association between the antibody levels, function, and CHMI defined clinical outcome during a 21-day follow-up period post infection using Cox proportional hazards regression. Results Antibody levels to the individual isolate VSAs, or to two ICAM1-binding DBLβ domains of PfEMP1, were not associated with a significantly reduced risk of developing parasitemia or of meeting treatment criteria after the challenge after adjusting for exposure. However, anti-VSA antibody breadth (i.e., cumulative response to all the isolates) was a significant predictor of reduced risk of requiring treatment [HR 0.23 (0.10-0.50) p= 0.0002]. Conclusion The breadth of IgG antibodies to VSAs, but not to individual isolate VSAs, is associated with protection in CHMI.
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Affiliation(s)
- Hannah W. Kimingi
- Kenya Medical Research Institute (KEMRI) Wellcome Trust Research Programme, Kilifi, Kenya
- Department of Biological Sciences, Pwani University, Kilifi, Kenya
| | - Ann W. Kinyua
- Kenya Medical Research Institute (KEMRI) Wellcome Trust Research Programme, Kilifi, Kenya
| | - Nicole A. Achieng
- Kenya Medical Research Institute (KEMRI) Wellcome Trust Research Programme, Kilifi, Kenya
| | - Kennedy M. Wambui
- Kenya Medical Research Institute (KEMRI) Wellcome Trust Research Programme, Kilifi, Kenya
- School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Shaban Mwangi
- Kenya Medical Research Institute (KEMRI) Wellcome Trust Research Programme, Kilifi, Kenya
| | - Roselyne Nguti
- Kenya Medical Research Institute (KEMRI) Wellcome Trust Research Programme, Kilifi, Kenya
- Department of Biological Sciences, Pwani University, Kilifi, Kenya
| | - Cheryl A. Kivisi
- Department of Biological Sciences, Pwani University, Kilifi, Kenya
- Pwani University Bioscience Research Centre, Pwani University, Kilifi, Kenya
| | - Anja T. R. Jensen
- Centre for Medical Parasitology, Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Philip Bejon
- Kenya Medical Research Institute (KEMRI) Wellcome Trust Research Programme, Kilifi, Kenya
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University Oxford, Oxford, United Kingdom
| | - Melisa C. Kapulu
- Kenya Medical Research Institute (KEMRI) Wellcome Trust Research Programme, Kilifi, Kenya
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University Oxford, Oxford, United Kingdom
| | - Abdirahman I. Abdi
- Kenya Medical Research Institute (KEMRI) Wellcome Trust Research Programme, Kilifi, Kenya
- Pwani University Bioscience Research Centre, Pwani University, Kilifi, Kenya
| | - Samson M. Kinyanjui
- Kenya Medical Research Institute (KEMRI) Wellcome Trust Research Programme, Kilifi, Kenya
- Pwani University Bioscience Research Centre, Pwani University, Kilifi, Kenya
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University Oxford, Oxford, United Kingdom
- School of Business Studies, Strathmore University, Nairobi, Kenya
- *Correspondence: Samson M. Kinyanjui,
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Gamain B, Dorin-Semblat D. Extraction and Immunoprecipitation of VAR2CSA, the PfEMP1 Associated with Placental Malaria. Methods Mol Biol 2022; 2470:257-271. [PMID: 35881351 DOI: 10.1007/978-1-0716-2189-9_19] [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 Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) is a key virulence factor for this human malaria parasite. During pregnancy, VAR2CSA is the only PfEMP1 variant expressed on the surface of infected erythrocytes that mediates adhesion to placenta cells and causes severe pregnancy outcomes.In this chapter, we present an optimized protocol to extract and immunoprecipitate endogenous VAR2CSA from the infected erythrocyte membrane phospholipid bilayer environment for subsequent characterization of the central role of VAR2CSA in placental malaria.
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Partey FD, Frimpong A, Ofori MF. Collection and Cryopreservation of Plasmodium falciparum Clinical Isolates in the Field. Methods Mol Biol 2022; 2470:11-17. [PMID: 35881334 DOI: 10.1007/978-1-0716-2189-9_2] [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
P. falciparum causes the most severe form of malaria in younger children and pregnant women. In vitro culture systems allow researchers to understand parasite biology, elucidate mechanism of host immunity and test efficacy of antimalarial agents or vaccines in preclinical studies. Most laboratory-adapted parasite strains predate the emergence of artemisinin-based drug combinations and mainly originate from Asia or Europe. To fully understand the biochemical and phenotypic characteristics of parasites, it is imperative that researchers are able to culture parasites circulating in an area to unravel any geographical differences at the population level. Ex vivo culturing of clinical isolates can be challenging when collecting samples in the field and requires technical expertise and equipment. To overcome this challenge, clinical isolates are cryopreserved in the field and transported to a laboratory for in vitro studies. In this protocol, we describe different methods of cryopreserving P. falciparum isolates in the field and thawing them for subsequent in vitro culture.
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Affiliation(s)
| | - Augustina Frimpong
- Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
| | - Michael Fokuo Ofori
- Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana.
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