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Askonas C, Storm J, Camarda G, Craig A, Pain A. Transcriptional responses of brain endothelium to Plasmodium falciparum patient-derived isolates in vitro. Microbiol Spectr 2024:e0072724. [PMID: 38864616 DOI: 10.1128/spectrum.00727-24] [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: 04/01/2024] [Accepted: 04/29/2024] [Indexed: 06/13/2024] Open
Abstract
A hallmark of cerebral malaria (CM) is sequestration of Plasmodium falciparum-infected erythrocytes (IE) within the brain microvasculature. Binding of IE to endothelium reduces microvascular flow and, combined with an inflammatory response, perturbs endothelial barrier function, resulting in breakdown of the blood-brain barrier (BBB). Cytoadherence leads to activation of the endothelium and alters a range of cell processes affecting signaling pathways, receptor expression, coagulation, and disruption of BBB integrity. Here, we investigated whether CM-derived parasites elicit differential effects on human brain microvascular endothelial cells (HBMECs), as compared to uncomplicated malaria (UM)-derived parasites. Patient-derived IE from UM and CM clinical cases, as well as non-binding skeleton-binding protein 1 knockout parasites, were overlaid onto tumour necrosis factor (TNF)-activated HBMECs. Gene expression analysis of endothelial responses was performed using probe-based assays of a panel of genes involved in inflammation, apoptosis, endothelial barrier function, and prostacyclin synthesis pathway. We observed a significant effect on endothelial transcriptional responses in the presence of IE, yet there was no significant correlation between HBMEC responses and type of clinical syndrome (UM or CM). Furthermore, there was no correlation between HBMEC gene expression and both binding itself and level of IE binding to HBMECs, as we detected the same change in endothelial responses when employing both binding and non-binding parasites. Our results suggest that interaction of IE with endothelial cells in this co-culture model induces some endothelial responses that are independent of clinical origin and independent of the expression of the major variant antigen Plasmodium falciparum erythrocyte membrane protein 1 on the IE surface. IMPORTANCE Cerebral malaria (CM) is the most prevalent and deadly complication of severe Plasmodium falciparum infection. A hallmark of this disease is sequestration of P. falciparum-infected erythrocytes (IE) in brain microvasculature that ultimately results in breakdown of the blood-brain barrier. Here, we compared the effect of P. falciparum parasites derived from uncomplicated malaria (UM) and CM cases on the relative gene expression of human brain microvascular endothelial cells (HBMECs) for a panel of genes. We observed a significant effect on the endothelial transcriptional response in the presence of IE, yet there is no significant correlation between HBMEC responses and the type of clinical syndrome (UM or CM). Furthermore, there was no correlation between HBMEC gene expression and both binding itself and the level of IE binding to HBMECs. Our results suggest that interaction of IE with endothelial cells induces endothelial responses that are independent of clinical origin and not entirely driven by surface Plasmodium falciparum erythrocyte membrane protein 1 expression.
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Affiliation(s)
- Caroline Askonas
- Pathogen Genomics Laboratory, Bioscience Program, Biological and Environmental Sciences and Engineering (BESE) Division, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Janet Storm
- Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Grazia Camarda
- Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Alister Craig
- Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, 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, Saudi Arabia
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2
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Gopinadhan A, Hughes JM, Conroy AL, John CC, Canfield SG, Datta D. A human pluripotent stem cell-derived in vitro model of the blood-brain barrier in cerebral malaria. Fluids Barriers CNS 2024; 21:38. [PMID: 38693577 PMCID: PMC11064301 DOI: 10.1186/s12987-024-00541-9] [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: 11/09/2023] [Accepted: 04/18/2024] [Indexed: 05/03/2024] Open
Abstract
BACKGROUND Blood-brain barrier (BBB) disruption is a central feature of cerebral malaria (CM), a severe complication of Plasmodium falciparum (Pf) infections. In CM, sequestration of Pf-infected red blood cells (Pf-iRBCs) to brain endothelial cells combined with inflammation, hemolysis, microvasculature obstruction and endothelial dysfunction mediates BBB disruption, resulting in severe neurologic symptoms including coma and seizures, potentially leading to death or long-term sequelae. In vitro models have advanced our knowledge of CM-mediated BBB disruption, but their physiological relevance remains uncertain. Using human induced pluripotent stem cell-derived brain microvascular endothelial cells (hiPSC-BMECs), we aimed to develop a novel in vitro model of the BBB in CM, exhibiting enhanced barrier properties. METHODS hiPSC-BMECs were co-cultured with HB3var03 strain Pf-iRBCs up to 9 h. Barrier integrity was measured using transendothelial electrical resistance (TEER) and sodium fluorescein permeability assays. Localization and expression of tight junction (TJ) proteins (occludin, zonula occludens-1, claudin-5), cellular adhesion molecules (ICAM-1, VCAM-1), and endothelial surface markers (EPCR) were determined using immunofluorescence imaging (IF) and western blotting (WB). Expression of angiogenic and cell stress markers were measured using multiplex proteome profiler arrays. RESULTS After 6-h of co-culture with Pf-iRBCs, hiPSC-BMECs showed reduced TEER and increased sodium fluorescein permeability compared to co-culture with uninfected RBCs, indicative of a leaky barrier. We observed disruptions in localization of occludin, zonula occludens-1, and claudin-5 by IF, but no change in protein expression by WB in Pf-iRBC co-cultures. Expression of ICAM-1 and VCAM-1 but not EPCR was elevated in hiPSC-BMECs with Pf-iRBC co-culture compared to uninfected RBC co-culture. In addition, there was an increase in expression of angiogenin, platelet factor-4, and phospho-heat shock protein-27 in the Pf-iRBCs co-culture compared to uninfected RBC co-culture. CONCLUSION These findings demonstrate the validity of our hiPSC-BMECs based model of the BBB, that displays enhanced barrier integrity and appropriate TJ protein localization. In the hiPSC-BMEC co-culture with Pf-iRBCs, reduced TEER, increased paracellular permeability, changes in TJ protein localization, increase in expression of adhesion molecules, and markers of angiogenesis and cellular stress all point towards a novel model with enhanced barrier properties, suitable for investigating pathogenic mechanisms underlying BBB disruption in CM.
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Affiliation(s)
- Adnan Gopinadhan
- Ryan White Center for Pediatric Infectious Disease and Global Health, Indiana University School of Medicine, R4-402D 1044 W. Walnut St., Indianapolis, IN, 46202, USA
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Jason M Hughes
- Department of Anatomy, Cell Biology, and Physiology, Indiana University School of Medicine, 620 Chestnut Street, Terre Haute, IN, 47809, USA
| | - Andrea L Conroy
- Ryan White Center for Pediatric Infectious Disease and Global Health, Indiana University School of Medicine, R4-402D 1044 W. Walnut St., Indianapolis, IN, 46202, USA
| | - Chandy C John
- Ryan White Center for Pediatric Infectious Disease and Global Health, Indiana University School of Medicine, R4-402D 1044 W. Walnut St., Indianapolis, IN, 46202, USA
| | - Scott G Canfield
- Department of Anatomy, Cell Biology, and Physiology, Indiana University School of Medicine, 620 Chestnut Street, Terre Haute, IN, 47809, USA.
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, 46202, USA.
| | - Dibyadyuti Datta
- Ryan White Center for Pediatric Infectious Disease and Global Health, Indiana University School of Medicine, R4-402D 1044 W. Walnut St., Indianapolis, IN, 46202, USA.
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3
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Alonso-Roman R, Mosig AS, Figge MT, Papenfort K, Eggeling C, Schacher FH, Hube B, Gresnigt MS. Organ-on-chip models for infectious disease research. Nat Microbiol 2024; 9:891-904. [PMID: 38528150 DOI: 10.1038/s41564-024-01645-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Accepted: 02/20/2024] [Indexed: 03/27/2024]
Abstract
Research on microbial pathogens has traditionally relied on animal and cell culture models to mimic infection processes in the host. Over recent years, developments in microfluidics and bioengineering have led to organ-on-chip (OoC) technologies. These microfluidic systems create conditions that are more physiologically relevant and can be considered humanized in vitro models. Here we review various OoC models and how they have been applied for infectious disease research. We outline the properties that make them valuable tools in microbiology, such as dynamic microenvironments, vascularization, near-physiological tissue constitutions and partial integration of functional immune cells, as well as their limitations. Finally, we discuss the prospects for OoCs and their potential role in future infectious disease research.
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Affiliation(s)
- Raquel Alonso-Roman
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology - Hans-Knöll-Institute (Leibniz-HKI), Jena, Germany
- Cluster of Excellence Balance of the Microverse, Friedrich Schiller University Jena, Jena, Germany
| | - Alexander S Mosig
- Cluster of Excellence Balance of the Microverse, Friedrich Schiller University Jena, Jena, Germany
- Institute of Biochemistry II, Jena University Hospital, Jena, Germany
- Center for Sepsis Control and Care, Jena University Hospital, Friedrich-Schiller University, Jena, Germany
| | - Marc Thilo Figge
- Cluster of Excellence Balance of the Microverse, Friedrich Schiller University Jena, Jena, Germany
- Applied Systems Biology Group, Leibniz-HKI, Jena, Germany
- Institute of Microbiology, Faculty of Biological Sciences, Friedrich Schiller University, Jena, Germany
| | - Kai Papenfort
- Cluster of Excellence Balance of the Microverse, Friedrich Schiller University Jena, Jena, Germany
- Institute of Microbiology, Faculty of Biological Sciences, Friedrich Schiller University, Jena, Germany
| | - Christian Eggeling
- Cluster of Excellence Balance of the Microverse, Friedrich Schiller University Jena, Jena, Germany
- Leibniz Institute of Photonic Technology, Leibniz Center for Photonics in Infection Research e.V., Jena, Germany
- Institute of Applied Optics and Biophysics, Friedrich Schiller University Jena, Jena, Germany
- Jena Center for Soft Matter, Jena, Germany
| | - Felix H Schacher
- Cluster of Excellence Balance of the Microverse, Friedrich Schiller University Jena, Jena, Germany
- Jena Center for Soft Matter, Jena, Germany
- Institute of Organic Chemistry and Macromolecular Chemistry, Friedrich Schiller University, Jena, Germany
| | - Bernhard Hube
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology - Hans-Knöll-Institute (Leibniz-HKI), Jena, Germany.
- Cluster of Excellence Balance of the Microverse, Friedrich Schiller University Jena, Jena, Germany.
- Institute of Microbiology, Faculty of Biological Sciences, Friedrich Schiller University, Jena, Germany.
| | - Mark S Gresnigt
- Cluster of Excellence Balance of the Microverse, Friedrich Schiller University Jena, Jena, Germany
- Junior Research Group Adaptive Pathogenicity Strategies, Leibniz-HKI, Jena, Germany
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Reyes RA, Raghavan SSR, Hurlburt NK, Introini V, Kana IH, Jensen RW, Martinez-Scholze E, Gestal-Mato M, Bau CB, Fernández-Quintero ML, Loeffler JR, Ferguson JA, Lee WH, Martin GM, Theander TG, Ssewanyana I, Feeney ME, Greenhouse B, Bol S, Ward AB, Bernabeu M, Pancera M, Turner L, Bunnik EM, Lavstsen T. Broadly inhibitory antibodies against severe malaria virulence proteins. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.25.577124. [PMID: 38328068 PMCID: PMC10849712 DOI: 10.1101/2024.01.25.577124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
Plasmodium falciparum pathology is driven by the accumulation of parasite-infected erythrocytes in microvessels. This process is mediated by the parasite's polymorphic erythrocyte membrane protein 1 (PfEMP1) adhesion proteins. A subset of PfEMP1 variants that bind human endothelial protein C receptor (EPCR) through their CIDRα1 domains is responsible for severe malaria pathogenesis. A longstanding question is whether individual antibodies can recognize the large repertoire of circulating PfEMP1 variants. Here, we describe two broadly reactive and binding-inhibitory human monoclonal antibodies against CIDRα1. The antibodies isolated from two different individuals exhibited a similar and consistent EPCR-binding inhibition of 34 CIDRα1 domains, representing five of the six subclasses of CIDRα1. Both antibodies inhibited EPCR binding of both recombinant full-length and native PfEMP1 proteins as well as parasite sequestration in bioengineered 3D brain microvessels under physiologically relevant flow conditions. Structural analyses of the two antibodies in complex with two different CIDRα1 antigen variants reveal similar binding mechanisms that depend on interactions with three highly conserved amino acid residues of the EPCR-binding site in CIDRα1. These broadly reactive antibodies likely represent a common mechanism of acquired immunity to severe malaria and offer novel insights for the design of a vaccine or treatment targeting severe malaria.
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Affiliation(s)
- Raphael A. Reyes
- Department of Microbiology, Immunology and Molecular Genetics, Long School of Medicine, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Sai Sundar Rajan Raghavan
- Centre for translational Medicine & Parasitology, Department of Immunology and Microbiology, University of Copenhagen and Department of Infectious Diseases, Righospitalet, Copenhagen, Denmark
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Nicholas K. Hurlburt
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Center, Seattle, WA 98109, USA
| | - Viola Introini
- European Molecular Biology Laboratory (EMBL) Barcelona, Barcelona 08003, Spain
| | - Ikhlaq Hussain Kana
- Centre for translational Medicine & Parasitology, Department of Immunology and Microbiology, University of Copenhagen and Department of Infectious Diseases, Righospitalet, Copenhagen, Denmark
| | - Rasmus W. Jensen
- Centre for translational Medicine & Parasitology, Department of Immunology and Microbiology, University of Copenhagen and Department of Infectious Diseases, Righospitalet, Copenhagen, Denmark
| | - Elizabeth Martinez-Scholze
- Department of Microbiology, Immunology and Molecular Genetics, Long School of Medicine, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Maria Gestal-Mato
- European Molecular Biology Laboratory (EMBL) Barcelona, Barcelona 08003, Spain
| | | | | | - Johannes R. Loeffler
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - James Alexander Ferguson
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Wen-Hsin Lee
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Greg Michael Martin
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Thor G. Theander
- Centre for translational Medicine & Parasitology, Department of Immunology and Microbiology, University of Copenhagen and Department of Infectious Diseases, Righospitalet, Copenhagen, Denmark
| | | | - Margaret E. Feeney
- Department of Medicine, University of California San Francisco, San Francisco, CA 94110, USA
- Department of Pediatrics, University of California San Francisco, San Francisco, CA 94110, USA
| | - Bryan Greenhouse
- Department of Medicine, University of California San Francisco, San Francisco, CA 94110, USA
| | - Sebastiaan Bol
- Department of Microbiology, Immunology and Molecular Genetics, Long School of Medicine, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Andrew B. Ward
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Maria Bernabeu
- European Molecular Biology Laboratory (EMBL) Barcelona, Barcelona 08003, Spain
| | - Marie Pancera
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Center, Seattle, WA 98109, USA
| | - Louise Turner
- Centre for translational Medicine & Parasitology, Department of Immunology and Microbiology, University of Copenhagen and Department of Infectious Diseases, Righospitalet, Copenhagen, Denmark
| | - Evelien M. Bunnik
- Department of Microbiology, Immunology and Molecular Genetics, Long School of Medicine, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Thomas Lavstsen
- Centre for translational Medicine & Parasitology, Department of Immunology and Microbiology, University of Copenhagen and Department of Infectious Diseases, Righospitalet, Copenhagen, Denmark
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5
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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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6
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Howard C, Joof F, Hu R, Smith JD, Zheng Y. Probing cerebral malaria inflammation in 3D human brain microvessels. Cell Rep 2023; 42:113253. [PMID: 37819760 DOI: 10.1016/j.celrep.2023.113253] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 09/08/2023] [Accepted: 09/08/2023] [Indexed: 10/13/2023] Open
Abstract
Sequestration of Plasmodium falciparum-infected erythrocytes (IEs) in the brain microcirculation is a hallmark of cerebral malaria (CM), which leads to endothelial activation, brain swelling, and death. Here, we probed CM inflammation in a perfusable 3D human brain microvessel model. 3D brain microvessels supported in vivo-like capacities for parasite binding and maturation in situ, leading to a distinct inflammatory response from the pro-inflammatory cytokine tumor necrosis factor α (TNF-α). By combining transcriptional analysis, imaging, and leukocyte perfusion, we showed that whereas TNF-α promotes a reversible inflammatory phenotype with widespread leukocyte recruitment, parasites induce unique stress response pathways and cause localized cell adhesivity changes, focal endothelial disruptions, and apoptosis. Furthermore, parasites modified the temporal kinetics of the TNF transcriptional response, suggesting augmented inflammatory damage with the two sequential stimuli. Our findings offer mechanistic insights into CM biology in a 3D brain microvessel mimetic platform and suggest that multiple events intersect to promote brain barrier inflammation in CM.
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Affiliation(s)
- Caitlin Howard
- Department of Bioengineering, University of Washington, Seattle, WA, USA; Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 98109, USA
| | - Fatou Joof
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA 98109, USA
| | - Ruoqian Hu
- Department of Bioengineering, University of Washington, Seattle, WA, USA; Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 98109, USA
| | - Joseph D Smith
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA 98109, USA; Department of Pediatrics, School of Medicine, University of Washington, Seattle, WA, USA.
| | - Ying Zheng
- Department of Bioengineering, University of Washington, Seattle, WA, USA; Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 98109, USA.
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7
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Juste-Lanas Y, Hervas-Raluy S, García-Aznar JM, González-Loyola A. Fluid flow to mimic organ function in 3D in vitro models. APL Bioeng 2023; 7:031501. [PMID: 37547671 PMCID: PMC10404142 DOI: 10.1063/5.0146000] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Accepted: 06/20/2023] [Indexed: 08/08/2023] Open
Abstract
Many different strategies can be found in the literature to model organ physiology, tissue functionality, and disease in vitro; however, most of these models lack the physiological fluid dynamics present in vivo. Here, we highlight the importance of fluid flow for tissue homeostasis, specifically in vessels, other lumen structures, and interstitium, to point out the need of perfusion in current 3D in vitro models. Importantly, the advantages and limitations of the different current experimental fluid-flow setups are discussed. Finally, we shed light on current challenges and future focus of fluid flow models applied to the newest bioengineering state-of-the-art platforms, such as organoids and organ-on-a-chip, as the most sophisticated and physiological preclinical platforms.
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Affiliation(s)
| | - Silvia Hervas-Raluy
- Department of Mechanical Engineering, Engineering Research Institute of Aragón (I3A), University of Zaragoza, Zaragoza, Spain
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8
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Akide Ndunge OB, Kilian N, Salman MM. Cerebral Malaria and Neuronal Implications of Plasmodium Falciparum Infection: From Mechanisms to Advanced Models. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2202944. [PMID: 36300890 PMCID: PMC9798991 DOI: 10.1002/advs.202202944] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 09/22/2022] [Indexed: 06/01/2023]
Abstract
Reorganization of host red blood cells by the malaria parasite Plasmodium falciparum enables their sequestration via attachment to the microvasculature. This artificially increases the dwelling time of the infected red blood cells within inner organs such as the brain, which can lead to cerebral malaria. Cerebral malaria is the deadliest complication patients infected with P. falciparum can experience and still remains a major public health concern despite effective antimalarial therapies. Here, the current understanding of the effect of P. falciparum cytoadherence and their secreted proteins on structural features of the human blood-brain barrier and their involvement in the pathogenesis of cerebral malaria are highlighted. Advanced 2D and 3D in vitro models are further assessed to study this devastating interaction between parasite and host. A better understanding of the molecular mechanisms leading to neuronal and cognitive deficits in cerebral malaria will be pivotal in devising new strategies to treat and prevent blood-brain barrier dysfunction and subsequent neurological damage in patients with cerebral malaria.
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Affiliation(s)
- Oscar Bate Akide Ndunge
- Department of Internal MedicineSection of Infectious DiseasesYale University School of Medicine300 Cedar StreetNew HavenCT06510USA
| | - Nicole Kilian
- Centre for Infectious Diseases, ParasitologyHeidelberg University HospitalIm Neuenheimer Feld 32469120HeidelbergGermany
| | - Mootaz M. Salman
- Department of PhysiologyAnatomy and GeneticsUniversity of OxfordOxfordOX1 3QUUK
- Kavli Institute for NanoScience DiscoveryUniversity of OxfordOxfordUK
- Oxford Parkinson's Disease CentreUniversity of OxfordOxfordUK
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9
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CD36-A Host Receptor Necessary for Malaria Parasites to Establish and Maintain Infection. Microorganisms 2022; 10:microorganisms10122356. [PMID: 36557610 PMCID: PMC9785914 DOI: 10.3390/microorganisms10122356] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 11/21/2022] [Accepted: 11/27/2022] [Indexed: 11/30/2022] Open
Abstract
Plasmodium falciparum-infected erythrocytes (PfIEs) present P. falciparum erythrocyte membrane protein 1 proteins (PfEMP1s) on the cell surface, via which they cytoadhere to various endothelial cell receptors (ECRs) on the walls of human blood vessels. This prevents the parasite from passing through the spleen, which would lead to its elimination. Each P. falciparum isolate has about 60 different PfEMP1s acting as ligands, and at least 24 ECRs have been identified as interaction partners. Interestingly, in every parasite genome sequenced to date, at least 75% of the encoded PfEMP1s have a binding domain for the scavenger receptor CD36 widely distributed on host endothelial cells and many other cell types. Here, we discuss why the interaction between PfIEs and CD36 is optimal to maintain a finely regulated equilibrium that allows the parasite to multiply and spread while causing minimal harm to the host in most infections.
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10
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Deletion of the Plasmodium falciparum exported protein PTP7 leads to Maurer’s clefts vesiculation, host cell remodeling defects, and loss of surface presentation of EMP1. PLoS Pathog 2022; 18:e1009882. [PMID: 35930605 PMCID: PMC9385048 DOI: 10.1371/journal.ppat.1009882] [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: 08/03/2021] [Revised: 08/17/2022] [Accepted: 06/19/2022] [Indexed: 11/19/2022] Open
Abstract
Presentation of the variant antigen, Plasmodium falciparum erythrocyte membrane protein 1 (EMP1), at knob-like protrusions on the surface of infected red blood cells, underpins the parasite’s pathogenicity. Here we describe a protein PF3D7_0301700 (PTP7), that functions at the nexus between the intermediate trafficking organelle, the Maurer’s cleft, and the infected red blood cell surface. Genetic disruption of PTP7 leads to accumulation of vesicles at the Maurer’s clefts, grossly aberrant knob morphology, and failure to deliver EMP1 to the red blood cell surface. We show that an expanded low complexity sequence in the C-terminal region of PTP7, identified only in the Laverania clade of Plasmodium, is critical for efficient virulence protein trafficking. We describe a malaria parasite protein, PTP7, involved in virulence factor trafficking that is associated with Maurer’s clefts and other trafficking compartments. Upon disruption of the PTP7 locus, the Maurer’s clefts become decorated with vesicles; the knobby protrusions on the host red blood cell surface are fewer and distorted; and trafficking of the virulence protein, EMP1, to the host red blood cell surface is ablated. We provide evidence that a region of PTP7 with low sequence complexity plays an important role in virulence protein trafficking from the Maurer’s clefts.
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11
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Adams Y, Jensen AR. Cerebral malaria - modelling interactions at the blood-brain barrier in vitro. Dis Model Mech 2022; 15:275963. [PMID: 35815443 PMCID: PMC9302004 DOI: 10.1242/dmm.049410] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The blood–brain barrier (BBB) is a continuous endothelial barrier that is supported by pericytes and astrocytes and regulates the passage of solutes between the bloodstream and the brain. This structure is called the neurovascular unit and serves to protect the brain from blood-borne disease-causing agents and other risk factors. In the past decade, great strides have been made to investigate the neurovascular unit for delivery of chemotherapeutics and for understanding how pathogens can circumvent the barrier, leading to severe and, at times, fatal complications. One such complication is cerebral malaria, in which Plasmodium falciparum-infected red blood cells disrupt the barrier function of the BBB, causing severe brain swelling. Multiple in vitro models of the BBB are available to investigate the mechanisms underlying the pathogenesis of cerebral malaria and other diseases. These range from single-cell monolayer cultures to multicellular BBB organoids and highly complex cerebral organoids. Here, we review the technologies available in malaria research to investigate the interaction between P. falciparum-infected red blood cells and the BBB, and discuss the advantages and disadvantages of each model. Summary: This Review discusses the available in vitro models to investigate the impact of adhesion of Plasmodium falciparum-infected red blood cells on the blood–brain barrier, a process associated with cerebral malaria.
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Affiliation(s)
- Yvonne Adams
- Centre for Medical Parasitology at the Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Anja Ramstedt Jensen
- Centre for Medical Parasitology at the Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen N, Denmark
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12
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Introini V, Govendir MA, Rayner JC, Cicuta P, Bernabeu M. Biophysical Tools and Concepts Enable Understanding of Asexual Blood Stage Malaria. Front Cell Infect Microbiol 2022; 12:908241. [PMID: 35711656 PMCID: PMC9192966 DOI: 10.3389/fcimb.2022.908241] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Accepted: 04/27/2022] [Indexed: 12/02/2022] Open
Abstract
Forces and mechanical properties of cells and tissues set constraints on biological functions, and are key determinants of human physiology. Changes in cell mechanics may arise from disease, or directly contribute to pathogenesis. Malaria gives many striking examples. Plasmodium parasites, the causative agents of malaria, are single-celled organisms that cannot survive outside their hosts; thus, thost-pathogen interactions are fundamental for parasite’s biological success and to the host response to infection. These interactions are often combinations of biochemical and mechanical factors, but most research focuses on the molecular side. However, Plasmodium infection of human red blood cells leads to changes in their mechanical properties, which has a crucial impact on disease pathogenesis because of the interaction of infected red blood cells with other human tissues through various adhesion mechanisms, which can be probed and modelled with biophysical techniques. Recently, natural polymorphisms affecting red blood cell biomechanics have also been shown to protect human populations, highlighting the potential of understanding biomechanical factors to inform future vaccines and drug development. Here we review biophysical techniques that have revealed new aspects of Plasmodium falciparum invasion of red blood cells and cytoadhesion of infected cells to the host vasculature. These mechanisms occur differently across Plasmodium species and are linked to malaria pathogenesis. We highlight promising techniques from the fields of bioengineering, immunomechanics, and soft matter physics that could be beneficial for studying malaria. Some approaches might also be applied to other phases of the malaria lifecycle and to apicomplexan infections with complex host-pathogen interactions.
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Affiliation(s)
- Viola Introini
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
- Cavendish Laboratory, University of Cambridge, Cambridge, United Kingdom
- *Correspondence: Viola Introini,
| | - Matt A. Govendir
- European Molecular Biology Laboratory (EMBL) Barcelona, Barcelona, Spain
| | - Julian C. Rayner
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
| | - Pietro Cicuta
- Cavendish Laboratory, University of Cambridge, Cambridge, United Kingdom
| | - Maria Bernabeu
- European Molecular Biology Laboratory (EMBL) Barcelona, Barcelona, Spain
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13
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Ortolan LS, Avril M, Xue J, Seydel KB, Zheng Y, Smith JD. Plasmodium falciparum Parasite Lines Expressing DC8 and Group A PfEMP1 Bind to Brain, Intestinal, and Kidney Endothelial Cells. Front Cell Infect Microbiol 2022; 12:813011. [PMID: 35155278 PMCID: PMC8831842 DOI: 10.3389/fcimb.2022.813011] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 01/10/2022] [Indexed: 11/13/2022] Open
Abstract
Cytoadhesion of Plasmodium falciparum-infected red blood cells is a virulence determinant associated with microvascular obstruction and organ complications. The gastrointestinal tract is a major site of sequestration in fatal cerebral malaria cases and kidney complications are common in severe malaria, but parasite interactions with these microvascular sites are poorly characterized. To study parasite tropism for different microvascular sites, we investigated binding of parasite lines to primary human microvascular endothelial cells from intestine (HIMEC) and peritubular kidney (HKMEC) sites. Of the three major host receptors for P. falciparum, CD36 had low or negligible expression; endothelial protein C receptor (EPCR) had the broadest constitutive expression; and intercellular adhesion molecule 1 (ICAM-1) was weakly expressed on resting cells and was strongly upregulated by TNF-α on primary endothelial cells from the brain, intestine, and peritubular kidney sites. By studying parasite lines expressing var genes linked to severe malaria, we provide evidence that both the DC8 and Group A EPCR-binding subsets of the P. falciparum erythrocyte membrane protein 1 (PfEMP1) family encodes binding affinity for brain, intestinal, and peritubular kidney endothelial cells, and that DC8 parasite adhesion was partially dependent on EPCR. Collectively, these findings raise the possibility of a brain-gut-kidney binding axis contributing to multi-organ complications in severe malaria.
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Affiliation(s)
- Luana S. Ortolan
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, WA, United States
| | - Marion Avril
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, WA, United States
| | - Jun Xue
- Department of Bioengineering, University of Washington, Seattle, WA, United States
| | - Karl B. Seydel
- Department of Osteopathic Medical Specialties, College of Osteopathic Medicine, Michigan State University, East Lansing, MI, United States
- Blantyre Malaria Project, Kamuzu University of Health Sciences, Blantyre, Malawi
| | - Ying Zheng
- Department of Bioengineering, University of Washington, Seattle, WA, United States
| | - Joseph D. Smith
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, WA, United States
- Department of Pediatrics, University of Washington, Seattle, WA, United States
- *Correspondence: Joseph D. Smith,
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14
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Storm J, Craig AG. Static Adhesion of Plasmodium falciparum-Infected Erythrocytes to Purified and Recombinant Receptors. Methods Mol Biol 2022; 2470:527-536. [PMID: 35881372 DOI: 10.1007/978-1-0716-2189-9_40] [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 pathology of Plasmodium falciparum malaria syndromes, such as cerebral malaria, severe anemia, respiratory distress, and malaria in pregnancy are associated with the cytoadherence of P. falciparum-infected erythrocytes (IEs) to host receptors. To investigate binding of laboratory strains or patient isolates to specific receptors, a relatively simple but informative method is a static binding assay. Purified protein receptors are absorbed onto polystyrene dishes, overlaid with a trophozoite IE suspension and incubated for a fixed time. After washing to remove unbound cells, the plates are fixed, stained, and adherent IEs counted by microscopy. Although simple, this assay requires careful implementation to provide reproducible results, but it is deliverable in relatively low-resource settings and so well matched to using fresh patient isolates for adhesion assays.
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Affiliation(s)
- Janet Storm
- Liverpool School of Tropical Medicine, Liverpool, UK
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15
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Oleinikov AV. Malaria Parasite Plasmodium falciparum Proteins on the Surface of Infected Erythrocytes as Targets for Novel Drug Discovery. BIOCHEMISTRY (MOSCOW) 2022; 87:S192-S177. [PMID: 35501996 PMCID: PMC8802247 DOI: 10.1134/s0006297922140152] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Specific adhesion (sequestration) of Plasmodium falciparum parasite-infected erythrocytes (IEs) in deep vascular beds can cause severe complications resulting in death. This review describes our work on the discovery, characterization, and optimization of novel inhibitors that specifically prevent adhesion of IEs to the host vasculature during severe malaria, especially its placental and cerebral forms. The main idea of using anti-adhesion drugs in severe malaria is to release sequestered parasites (or prevent additional sequestration) as quickly as possible. This may significantly improve the outcomes for patients with severe malaria by decreasing local and systemic inflammation associated with the disease and reestablishing the microvascular blood flow. To identify anti-malarial adhesion-inhibiting molecules, we have developed a high-throughput (HT) screening approach and found a number of promising leads that can be further developed into anti-adhesion drugs providing an efficient adjunct therapy against severe forms of malaria.
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Affiliation(s)
- Andrew V Oleinikov
- Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL 33428, USA.
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16
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Piatti L, Howard CC, Zheng Y, Bernabeu M. Binding of Plasmodium falciparum-Infected Red Blood Cells to Engineered 3D Microvessels. Methods Mol Biol 2022; 2470:557-585. [PMID: 35881375 DOI: 10.1007/978-1-0716-2189-9_43] [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-infected red blood cell (iRBC) sequestration in the microvasculature is a pivotal event in severe malaria pathogenesis. In vitro binding assays using endothelial cell monolayers under static and flow conditions have revealed key ligand-receptor interactions for iRBC sequestration. However, mechanisms remain elusive for iRBC sequestration in specific vascular locations, which prevents further development of effective therapies. New models are needed to better recapitulate the complex geometry of blood flow in human blood vessels and organ-specific vascular signatures. Recent advances in engineering 3D microvessels in vitro have emerged as promising technologies to not only model complex human vascular structures but also allow for precise and step-wise control of individual biological and biomechanical parameters. By designing networks with different branching structures and change of vessel diameter along the flow path, these models recapitulate pressure and flow changes occurring in vivo. Here, we describe the methodology employed to build 3D microvessels using soft lithography and injection molding techniques, as well as the protocol to fabricate capillary-size vessels through collagen photoablation. Furthermore, we describe the methodology of using these models to study malaria and narrate necessary steps for perfusion of P. falciparum through 3D microvessels and different options to quantify P. falciparum-iRBC binding.
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Affiliation(s)
- Livia Piatti
- European Molecular Biology Laboratory (EMBL) Barcelona, Barcelona, Spain
| | - Caitlin C Howard
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Ying Zheng
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Maria Bernabeu
- European Molecular Biology Laboratory (EMBL) Barcelona, Barcelona, Spain.
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17
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Long RKM, Piatti L, Korbmacher F, Bernabeu M. Understanding parasite-brain microvascular interactions with engineered 3D blood-brain barrier models. Mol Microbiol 2021; 117:693-704. [PMID: 34837419 DOI: 10.1111/mmi.14852] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 11/23/2021] [Indexed: 01/25/2023]
Abstract
Microbial interactions with the blood-brain barrier (BBB) can be highly pathogenic and are still not well understood. Among these, parasites present complex interactions with the brain microvasculature that are difficult to decipher using experimental animal models or reductionist 2D in vitro cultures. Novel 3D engineered blood-brain barrier models hold great promise to overcome limitations in traditional research approaches. These models better mimic the intricate 3D architecture of the brain microvasculature and recapitulate several aspects of BBB properties, physiology, and function. Moreover, they provide improved control over biophysical and biochemical experimental parameters and are compatible with advanced imaging and molecular biology techniques. Here, we review design considerations and methodologies utilized to successfully engineer BBB microvessels. Finally, we highlight the advantages and limitations of existing engineered models and propose applications to study parasite interactions with the BBB, including mechanisms of barrier disruption.
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Affiliation(s)
- Rory K M Long
- European Molecular Biology Laboratory (EMBL) Barcelona, Barcelona, Spain
| | - Livia Piatti
- European Molecular Biology Laboratory (EMBL) Barcelona, Barcelona, Spain
| | | | - Maria Bernabeu
- European Molecular Biology Laboratory (EMBL) Barcelona, Barcelona, Spain
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18
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Developmental angiocrine diversification of endothelial cells for organotypic regeneration. Dev Cell 2021; 56:3042-3051. [PMID: 34813766 DOI: 10.1016/j.devcel.2021.10.020] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 10/17/2021] [Accepted: 10/26/2021] [Indexed: 02/08/2023]
Abstract
Adult organs are vascularized by specialized blood vessels. In addition to inter-organ vascular heterogeneity, each organ is arborized by structurally and functionally diversified populations of endothelial cells (ECs). The molecular pathways that are induced to orchestrate inter- and intra- organ vascular heterogeneity and zonation are shaped during development and fully specified postnatally. Notably, intra-organ specialization of ECs is associated with induction of angiocrine factors that guide cross-talk between ECs and parenchymal cells, establishing co-zonated vascular regions within each organ. In this review, we describe how microenvironmental tissue-specific biophysical, biochemical, immune, and inflammatory cues dictate the specialization of ECs with zonated functions. We delineate how physiological and biophysical stressors in the developing liver, lung, and kidney vasculature induce specialization of capillary beds. Deciphering mechanisms by which vascular microvasculature diversity is attained could set the stage for treating regenerative disorders and promote healing of organs without provoking fibrosis.
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19
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Mandrycky CJ, Howard CC, Rayner SG, Shin YJ, Zheng Y. Organ-on-a-chip systems for vascular biology. J Mol Cell Cardiol 2021; 159:1-13. [PMID: 34118217 DOI: 10.1016/j.yjmcc.2021.06.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 05/03/2021] [Accepted: 06/06/2021] [Indexed: 12/18/2022]
Abstract
Organ-on-a-chip (OOC) platforms involve the miniaturization of cell culture systems and enable a variety of novel experimental approaches. These range from modeling the independent effects of biophysical forces on cells to screening novel drugs in multi-organ microphysiological systems, all within microscale devices. As in living systems, the incorporation of vascular structure is a key feature common to almost all organ-on-a-chip systems. In this review we highlight recent advances in organ-on-a-chip technologies with a focus on the vasculature. We first present the developmental process of the blood vessels through which vascular cells assemble into networks and remodel to form complex vascular beds under flow. We then review self-assembled vascular models and flow systems for the study of vascular development and biology as well as pre-patterned vascular models for the generation of perfusable microvessels for modeling vascular and tissue function. We finally conclude with a perspective on developing future OOC approaches for studying different aspects of vascular biology. We highlight the fit for purpose selection of OOC models towards either simple but powerful testbeds for therapeutic development, or complex vasculature to accurately replicate human physiology for specific disease modeling and tissue regeneration.
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Affiliation(s)
- Christian J Mandrycky
- Department of Bioengineering, University of Washington, 3720 15th Ave NE, Seattle, WA 98105, USA.
| | - Caitlin C Howard
- Department of Bioengineering, University of Washington, 3720 15th Ave NE, Seattle, WA 98105, USA.
| | - Samuel G Rayner
- Department of Bioengineering, University of Washington, 3720 15th Ave NE, Seattle, WA 98105, USA; Department of Medicine; Division of Pulmonary, Critical Care and Sleep Medicine, University of Washington, Seattle, WA 98195, USA.
| | - Yu Jung Shin
- Department of Bioengineering, University of Washington, 3720 15th Ave NE, Seattle, WA 98105, USA.
| | - Ying Zheng
- Department of Bioengineering, University of Washington, 3720 15th Ave NE, Seattle, WA 98105, USA; Institute for Stem Cell and Regenerative Medicine, Seattle, WA 98195, USA.
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20
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Azasi Y, Low LM, Just AN, Raghavan SSR, Wang CW, Valenzuela-Leon P, Rowe JA, Smith JD, Lavstsen T, Turner L, Calvo E, Miller LH. Complement C1s cleaves PfEMP1 at interdomain conserved sites inhibiting Plasmodium falciparum cytoadherence. Proc Natl Acad Sci U S A 2021; 118:e2104166118. [PMID: 34035177 PMCID: PMC8179237 DOI: 10.1073/pnas.2104166118] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2023] Open
Abstract
Cytoadhesion of Plasmodium falciparum-infected erythrocytes (IEs) to the endothelial lining of blood vessels protects parasites from splenic destruction, but also leads to detrimental inflammation and vessel occlusion. Surface display of the P. falciparum erythrocyte membrane protein 1 (PfEMP1) adhesion ligands exposes them to host antibodies and serum proteins. PfEMP1 are important targets of acquired immunity to malaria, and through evolution, the protein family has expanded and diversified to bind a select set of host receptors through antigenically diversified receptor-binding domains. Here, we show that complement component 1s (C1s) in serum cleaves PfEMP1 at semiconserved arginine motifs located at interdomain regions between the receptor-binding domains, rendering the IE incapable of binding the two main PfEMP1 receptors, CD36 and endothelial protein C receptor (EPCR). Bioinformatic analyses of PfEMP1 protein sequences from 15 P. falciparum genomes found the C1s motif was present in most PfEMP1 variants. Prediction of C1s cleavage and loss of binding to endothelial receptors was further corroborated by testing of several different parasite lines. These observations suggest that the parasites have maintained susceptibility for cleavage by the serine protease, C1s, and provides evidence for a complex relationship between the complement system and the P. falciparum cytoadhesion virulence determinant.
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Affiliation(s)
- Yvonne Azasi
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, NIH, Rockville, MD 20852
| | - Leanne M Low
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, NIH, Rockville, MD 20852
| | - Ashley N Just
- Centre for Medical Parasitology, Department of International Health, Immunology and Microbiology, University of Copenhagen, 2200 Copenhagen, Denmark
- Department of Infectious Diseases, Rigshospitalet, 2100 Copenhagen, Denmark
| | - Sai S R Raghavan
- Centre for Medical Parasitology, Department of International Health, Immunology and Microbiology, University of Copenhagen, 2200 Copenhagen, Denmark
- Department of Infectious Diseases, Rigshospitalet, 2100 Copenhagen, Denmark
| | - Christian W Wang
- Centre for Medical Parasitology, Department of International Health, Immunology and Microbiology, University of Copenhagen, 2200 Copenhagen, Denmark
- Department of Infectious Diseases, Rigshospitalet, 2100 Copenhagen, Denmark
| | - Paola Valenzuela-Leon
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, NIH, Rockville, MD 20852
| | - J Alexandra Rowe
- Centre for Immunity, Infection and Evolution, University of Edinburgh, Edinburgh EH9 3FL, United Kingdom
- Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, United Kingdom
| | - Joseph D Smith
- Center for Global Infectious Disease Resesarch, Seattle Children's Research Institute, Seattle, WA 98109
- Department of Pediatrics, University of Washington, Seattle, WA 98195
- Department of Global Health, University of Washington, Seattle, WA 98195
| | - Thomas Lavstsen
- Centre for Medical Parasitology, Department of International Health, Immunology and Microbiology, University of Copenhagen, 2200 Copenhagen, Denmark
- Department of Infectious Diseases, Rigshospitalet, 2100 Copenhagen, Denmark
| | - Louise Turner
- Centre for Medical Parasitology, Department of International Health, Immunology and Microbiology, University of Copenhagen, 2200 Copenhagen, Denmark
- Department of Infectious Diseases, Rigshospitalet, 2100 Copenhagen, Denmark
| | - Eric Calvo
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, NIH, Rockville, MD 20852;
| | - Louis H Miller
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, NIH, Rockville, MD 20852;
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21
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Chesnokov O, Visitdesotrakul P, Kalani K, Nefzi A, Oleinikov AV. Small Molecule Compounds Identified from Mixture-Based Library Inhibit Binding between Plasmodium falciparum Infected Erythrocytes and Endothelial Receptor ICAM-1. Int J Mol Sci 2021; 22:ijms22115659. [PMID: 34073419 PMCID: PMC8198633 DOI: 10.3390/ijms22115659] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 05/19/2021] [Accepted: 05/22/2021] [Indexed: 12/17/2022] Open
Abstract
Specific adhesion of P. falciparum parasite-infected erythrocytes (IE) in deep vascular beds can result in severe complications, such as cerebral malaria, placental malaria, respiratory distress, and severe anemia. Cerebral malaria and severe malaria syndromes were associated previously with sequestration of IE to a microvasculature receptor ICAM-1. The screening of Torrey Pines Scaffold Ranking library, which consists of more than 30 million compounds designed around 75 molecular scaffolds, identified small molecules that inhibit cytoadhesion of ICAM-1-binding IE to surface-immobilized receptor at IC50 range down to ~350 nM. With their low cytotoxicity toward erythrocytes and human endothelial cells, these molecules might be suitable for development into potentially effective adjunct anti-adhesion drugs to treat cerebral and/or severe malaria syndromes. Our two-step high-throughput screening approach is specifically designed to work with compound mixtures to make screening and deconvolution to single active compounds fast and efficient.
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Affiliation(s)
- Olga Chesnokov
- Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL 33428, USA
| | | | - Komal Kalani
- Center for Translational Science, Florida International University (FIU), Port Saint Lucie, FL 34987, USA
| | - Adel Nefzi
- Center for Translational Science, Florida International University (FIU), Port Saint Lucie, FL 34987, USA
| | - Andrew V Oleinikov
- Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL 33428, USA
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22
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Milne K, Ivens A, Reid AJ, Lotkowska ME, O'Toole A, Sankaranarayanan G, Munoz Sandoval D, Nahrendorf W, Regnault C, Edwards NJ, Silk SE, Payne RO, Minassian AM, Venkatraman N, Sanders MJ, Hill AVS, Barrett M, Berriman M, Draper SJ, Rowe JA, Spence PJ. Mapping immune variation and var gene switching in naive hosts infected with Plasmodium falciparum. eLife 2021; 10:e62800. [PMID: 33648633 PMCID: PMC7924948 DOI: 10.7554/elife.62800] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Accepted: 02/09/2021] [Indexed: 02/06/2023] Open
Abstract
Falciparum malaria is clinically heterogeneous and the relative contribution of parasite and host in shaping disease severity remains unclear. We explored the interaction between inflammation and parasite variant surface antigen (VSA) expression, asking whether this relationship underpins the variation observed in controlled human malaria infection (CHMI). We uncovered marked heterogeneity in the host response to blood challenge; some volunteers remained quiescent, others triggered interferon-stimulated inflammation and some showed transcriptional evidence of myeloid cell suppression. Significantly, only inflammatory volunteers experienced hallmark symptoms of malaria. When we tracked temporal changes in parasite VSA expression to ask whether variants associated with severe disease rapidly expand in naive hosts, we found no transcriptional evidence to support this hypothesis. These data indicate that parasite variants that dominate severe malaria do not have an intrinsic growth or survival advantage; instead, they presumably rely upon infection-induced changes in their within-host environment for selection.
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Affiliation(s)
- Kathryn Milne
- Institute of Immunology and Infection Research, University of EdinburghEdinburghUnited Kingdom
| | - Alasdair Ivens
- Institute of Immunology and Infection Research, University of EdinburghEdinburghUnited Kingdom
- Centre for Immunity, Infection and Evolution, University of EdinburghEdinburghUnited Kingdom
| | - Adam J Reid
- Wellcome Sanger InstituteCambridgeUnited Kingdom
| | | | - Aine O'Toole
- Centre for Immunity, Infection and Evolution, University of EdinburghEdinburghUnited Kingdom
- Institute of Evolutionary Biology, University of EdinburghEdinburghUnited Kingdom
| | | | - Diana Munoz Sandoval
- Institute of Immunology and Infection Research, University of EdinburghEdinburghUnited Kingdom
- Instituto de Microbiologia, Universidad San Francisco de QuitoQuitoEcuador
| | - Wiebke Nahrendorf
- Institute of Immunology and Infection Research, University of EdinburghEdinburghUnited Kingdom
| | - Clement Regnault
- Wellcome Centre for Integrative Parasitology, University of GlasgowGlasgowUnited Kingdom
- Glasgow Polyomics, University of GlasgowGlasgowUnited Kingdom
| | - Nick J Edwards
- The Jenner Institute, University of OxfordOxfordUnited Kingdom
| | - Sarah E Silk
- The Jenner Institute, University of OxfordOxfordUnited Kingdom
| | - Ruth O Payne
- The Jenner Institute, University of OxfordOxfordUnited Kingdom
| | | | | | | | - Adrian VS Hill
- The Jenner Institute, University of OxfordOxfordUnited Kingdom
| | - Michael Barrett
- Wellcome Centre for Integrative Parasitology, University of GlasgowGlasgowUnited Kingdom
- Glasgow Polyomics, University of GlasgowGlasgowUnited Kingdom
| | | | - Simon J Draper
- The Jenner Institute, University of OxfordOxfordUnited Kingdom
| | - J Alexandra Rowe
- Institute of Immunology and Infection Research, University of EdinburghEdinburghUnited Kingdom
- Centre for Immunity, Infection and Evolution, University of EdinburghEdinburghUnited Kingdom
| | - Philip J Spence
- Institute of Immunology and Infection Research, University of EdinburghEdinburghUnited Kingdom
- Centre for Immunity, Infection and Evolution, University of EdinburghEdinburghUnited Kingdom
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23
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Bioengineered 3D Microvessels for Investigating Plasmodium falciparum Pathogenesis. Trends Parasitol 2021; 37:401-413. [PMID: 33485788 DOI: 10.1016/j.pt.2020.12.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 12/15/2020] [Accepted: 12/25/2020] [Indexed: 12/18/2022]
Abstract
Plasmodium falciparum pathogenesis is complex and intimately connected to vascular physiology. This is exemplified by cerebral malaria (CM), a neurovascular complication that accounts for most of the malaria deaths worldwide. P. falciparum sequestration in the brain microvasculature is a hallmark of CM and is not replicated in animal models. Numerous aspects of the disease are challenging to fully understand from clinical studies, such as parasite binding tropism or causal pathways in blood-brain barrier breakdown. Recent bioengineering approaches allow for the generation of 3D microvessels and organ-specific vasculature that provide precise control of vessel architecture and flow dynamics, and hold great promise for malaria research. Here, we discuss recent and future applications of bioengineered microvessels in malaria pathogenesis research.
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24
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de Koning-Ward TF, Boddey JA, Fowkes FJI. Molecular approaches to Malaria 2020. Cell Microbiol 2020; 23:e13289. [PMID: 33197142 DOI: 10.1111/cmi.13289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 11/08/2020] [Accepted: 11/10/2020] [Indexed: 11/30/2022]
Abstract
Twenty years ago the Molecular Approaches to Malaria conference was conceived as a forum to present the very latest advances in malaria research and to consolidate and forge new collaborative links between international researchers. The 6th MAM conference, held in February 2020 in Australia, provided 5 days of stimulating scientific exchange and highlighted the incredible malaria research conducted globally that is providing the critical knowledge and cutting-edge technological tools needed to control and ultimately eliminate malaria.
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Affiliation(s)
| | - Justin A Boddey
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia.,Department of Medical Biology, The University of Melbourne, Parkville, Australia
| | - Freya J I Fowkes
- The Burnet Institute, Melbourne, Australia.,Department of Public Health and Preventive Medicine, Monash University, Melbourne, Australia.,Melbourne School of Population and Global Health, The University of Melbourne, Carlton, Australia
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25
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Mita-Mendoza NK, Magallon-Tejada A, Parmar P, Furtado R, Aldrich M, Saidi A, Taylor T, Smith J, Seydel K, Daily JP. Dimethyl fumarate reduces TNF and Plasmodium falciparum induced brain endothelium activation in vitro. Malar J 2020; 19:376. [PMID: 33087130 PMCID: PMC7579885 DOI: 10.1186/s12936-020-03447-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2020] [Accepted: 10/16/2020] [Indexed: 11/10/2022] Open
Abstract
Background Cerebral malaria (CM) is associated with morbidity and mortality despite the use of potent anti-malarial agents. Brain endothelial cell activation and dysfunction from oxidative and inflammatory host responses and products released by Plasmodium falciparum-infected erythrocytes (IE), are likely the major contributors to the encephalopathy, seizures, and brain swelling that are associated with CM. The development of adjunctive therapy to reduce the pathological consequences of host response pathways could improve outcomes. A potentially protective role of the nuclear factor E2-related factor 2 (NRF2) pathway, which serves as a therapeutic target in brain microvascular diseases and central nervous system (CNS) inflammatory diseases such as multiple sclerosis was tested to protect endothelial cells in an in vitro culture system subjected to tumour necrosis factor (TNF) or infected red blood cell exposure. NRF2 is a transcription factor that mediates anti-oxidant and anti-inflammatory responses. Methods To accurately reflect clinically relevant parasite biology a unique panel of parasite isolates derived from patients with stringently defined CM was developed. The effect of TNF and these parasite lines on primary human brain microvascular endothelial cell (HBMVEC) activation in an in vitro co-culture model was tested. HBMVEC activation was measured by cellular release of IL6 and nuclear translocation of NFκB. The transcriptional and functional effects of dimethyl fumarate (DMF), an FDA approved drug which induces the NRF2 pathway, on host and parasite induced HBMVEC activation was characterized. In addition, the effect of DMF on parasite binding to TNF stimulated HBMVEC in a semi-static binding assay was examined. Results Transcriptional profiling demonstrates that DMF upregulates the NRF2-Mediated Oxidative Stress Response, ErbB4 Signaling Pathway, Peroxisome Proliferator-activated Receptor (PPAR) Signaling and downregulates iNOS Signaling and the Neuroinflammation Signaling Pathway on TNF activated HBMVEC. The parasite lines derived from eight paediatric CM patients demonstrated increased binding to TNF activated HBMVEC and varied in their binding and activation of HBMVEC. Overall DMF reduced both TNF and CM derived parasite activation of HBMVEC. Conclusions These findings provide evidence that targeting the NRF2 pathway in TNF and parasite activated HBMVEC mediates multiple protective pathways and may represent a novel adjunctive therapy to improve infection outcomes in CM.
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Affiliation(s)
- Neida K Mita-Mendoza
- Department of Microbiology & Immunology and Infectious Diseases, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Ariel Magallon-Tejada
- Seattle Biomedical Research Institute, Seattle, WA, USA.,Department of Research in Parasitology, Gorgas Memorial Research Institute for Health Studies, Panama City, Panama
| | - Priyanka Parmar
- Division of Infectious Diseases, Department of Medicine, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Raquel Furtado
- Department of Microbiology & Immunology and Infectious Diseases, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Margaret Aldrich
- Division of Infectious Diseases, Department of Medicine, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Alex Saidi
- Blantyre Malaria Project, University of Malawi College of Medicine, Blantyre 3, Malawi
| | - Terrie Taylor
- Blantyre Malaria Project, University of Malawi College of Medicine, Blantyre 3, Malawi.,Department of Osteopathic Medical Specialties, College of Osteopathic Medicine, Michigan State University, East Lansing, MI, USA
| | - Joe Smith
- Seattle Children's Research Institute, Seattle, WA, USA.,Department of Global Health, University of Washington, Seattle, WA, USA
| | - Karl Seydel
- Blantyre Malaria Project, University of Malawi College of Medicine, Blantyre 3, Malawi.,Department of Osteopathic Medical Specialties, College of Osteopathic Medicine, Michigan State University, East Lansing, MI, USA
| | - Johanna P Daily
- Department of Microbiology & Immunology and Infectious Diseases, Albert Einstein College of Medicine, Bronx, NY, USA. .,Division of Infectious Diseases, Department of Medicine, Albert Einstein College of Medicine, Bronx, NY, USA.
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26
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Pereira DMS, Carvalho Júnior AR, Lacerda EMDCB, da Silva LCN, Marinho CRF, André E, Fernandes ES. Oxidative and nitrosative stresses in cerebral malaria: can we target them to avoid a bad prognosis? J Antimicrob Chemother 2020; 75:1363-1373. [PMID: 32105324 DOI: 10.1093/jac/dkaa032] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
There is currently a global effort to reduce malaria morbidity and mortality. However, malaria still results in the deaths of thousands of people every year. Malaria is caused by Plasmodium spp., parasites transmitted through the bite of an infected female Anopheles mosquito. Treatment timing plays a decisive role in reducing mortality and sequelae associated with the severe forms of the disease such as cerebral malaria (CM). The available antimalarial therapy is considered effective but parasite resistance to these drugs has been observed in some countries. Antimalarial drugs act by increasing parasite lysis, especially through targeting oxidative stress pathways. Here we discuss the roles of reactive oxygen species and reactive nitrogen intermediates in CM as a result of host-parasite interactions. We also present evidence of the potential contribution of oxidative and nitrosative stress-based antimalarial drugs to disease treatment and control.
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Affiliation(s)
| | | | | | | | | | - Eunice André
- Departamento de Farmacologia, Universidade Federal do Paraná, Curitiba, PR, Brazil
| | - Elizabeth Soares Fernandes
- Programa de Pós-graduação, Universidade CEUMA, São Luís, MA, Brazil.,Instituto de Pesquisa Pelé Pequeno Príncipe, Curitiba, PR, Brazil.,Faculdades Pequeno Príncipe, Curitiba, PR, Brazil
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27
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Abstract
In February 2020, the European Molecular Biology Laboratory (EMBL) and the Institute for Bioengineering of Catalonia (IBEC) joined forces to unite researchers from all over the globe to discuss emerging topics in 'Engineering Multicellular Systems'. As we review here, key themes that arose throughout the meeting included the ethics of organoids in developmental biology, bottom-up versus top-down models, tissue organizing principles, and the future of improving these systems to better mimic the natural world.
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Affiliation(s)
- Kristina Haase
- EMBL Barcelona, Carrer/Dr. Aiguader 88, Barcelona 08003, Spain
| | - Benjamin S Freedman
- Division of Nephrology, Kidney Research Institute, and Institute for Stem Cell and Regenerative Medicine, Department of Pathology (Adjunct), and Department of Medicine, University of Washington School of Medicine, Seattle, WA 98109, USA
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28
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Jensen AR, Adams Y, Hviid L. Cerebral Plasmodium falciparum malaria: The role of PfEMP1 in its pathogenesis and immunity, and PfEMP1-based vaccines to prevent it. Immunol Rev 2020; 293:230-252. [PMID: 31562653 PMCID: PMC6972667 DOI: 10.1111/imr.12807] [Citation(s) in RCA: 81] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 09/04/2019] [Accepted: 09/09/2019] [Indexed: 12/13/2022]
Abstract
Malaria, a mosquito-borne infectious disease caused by parasites of the genus Plasmodium continues to be a major health problem worldwide. The unicellular Plasmodium-parasites have the unique capacity to infect and replicate within host erythrocytes. By expressing variant surface antigens Plasmodium falciparum has evolved to avoid protective immune responses; as a result in endemic areas anti-malaria immunity develops gradually over many years of multiple and repeated infections. We are studying the role of Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) expressed by asexual stages of P. falciparum responsible for the pathogenicity of severe malaria. The immunopathology of falciparum malaria has been linked to cyto-adhesion of infected erythrocytes to specific host receptors. A greater appreciation of the PfEMP1 molecules important for the development of protective immunity and immunopathology is a prerequisite for the rational discovery and development of a safe and protective anti-disease malaria vaccine. Here we review the role of ICAM-1 and EPCR receptor adhering falciparum-parasites in the development of severe malaria; we discuss our current research to understand the factors involved in the pathogenesis of cerebral malaria and the feasibility of developing a vaccine targeted specifically to prevent this disease.
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Affiliation(s)
- Anja Ramstedt Jensen
- Centre for Medical Parasitology at Department of Immunology and MicrobiologyFaculty of Health and Medical SciencesUniversity of CopenhagenCopenhagenDenmark
| | - Yvonne Adams
- Centre for Medical Parasitology at Department of Immunology and MicrobiologyFaculty of Health and Medical SciencesUniversity of CopenhagenCopenhagenDenmark
| | - Lars Hviid
- Centre for Medical Parasitology at Department of Immunology and MicrobiologyFaculty of Health and Medical SciencesUniversity of CopenhagenCopenhagenDenmark
- Department of Infectious DiseasesRigshospitaletCopenhagenDenmark
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29
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Arakawa C, Gunnarsson C, Howard C, Bernabeu M, Phong K, Yang E, DeForest CA, Smith JD, Zheng Y. Biophysical and biomolecular interactions of malaria-infected erythrocytes in engineered human capillaries. SCIENCE ADVANCES 2020; 6:eaay7243. [PMID: 32010773 PMCID: PMC6968943 DOI: 10.1126/sciadv.aay7243] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2019] [Accepted: 11/20/2019] [Indexed: 05/14/2023]
Abstract
Microcirculatory obstruction is a hallmark of severe malaria, but mechanisms of parasite sequestration are only partially understood. Here, we developed a robust three-dimensional microvessel model that mimics the arteriole-capillary-venule (ACV) transition consisting of a narrow 5- to 10-μm-diameter capillary region flanked by arteriole- or venule-sized vessels. Using this platform, we investigated red blood cell (RBC) transit at the single cell and at physiological hematocrits. We showed normal RBCs deformed via in vivo-like stretching and tumbling with negligible interactions with the vessel wall. By comparison, Plasmodium falciparum-infected RBCs exhibited virtually no deformation and rapidly accumulated in the capillary-sized region. Comparison of wild-type parasites to those lacking either cytoadhesion ligands or membrane-stiffening knobs showed highly distinctive spatial and temporal kinetics of accumulation, linked to velocity transition in ACVs. Our findings shed light on mechanisms of microcirculatory obstruction in malaria and establish a new platform to study hematologic and microvascular diseases.
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Affiliation(s)
- Christopher Arakawa
- Department of Bioengineering, University of Washington, Seattle, WA 98105, USA
| | - Celina Gunnarsson
- Department of Bioengineering, University of Washington, Seattle, WA 98105, USA
| | - Caitlin Howard
- Department of Bioengineering, University of Washington, Seattle, WA 98105, USA
| | - Maria Bernabeu
- Seattle Children’s Research Institute, Seattle, WA 98101, USA
| | - Kiet Phong
- Department of Bioengineering, University of Washington, Seattle, WA 98105, USA
| | - Eric Yang
- Department of Bioengineering, University of Washington, Seattle, WA 98105, USA
| | - Cole A. DeForest
- Department of Bioengineering, University of Washington, Seattle, WA 98105, USA
- Department of Chemical Engineering, University of Washington, Seattle, WA 98195, USA
| | - Joseph D. Smith
- Seattle Children’s Research Institute, Seattle, WA 98101, USA
- Department of Global Health, University of Washington, Seattle, WA 98105, USA
| | - Ying Zheng
- Department of Bioengineering, University of Washington, Seattle, WA 98105, USA
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30
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Figarella K, Wolburg H, Garaschuk O, Duszenko M. Microglia in neuropathology caused by protozoan parasites. Biol Rev Camb Philos Soc 2019; 95:333-349. [PMID: 31682077 DOI: 10.1111/brv.12566] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 10/04/2019] [Accepted: 10/07/2019] [Indexed: 12/31/2022]
Abstract
Involvement of the central nervous system (CNS) is the most severe consequence of some parasitic infections. Protozoal infections comprise a group of diseases that together affect billions of people worldwide and, according to the World Health Organization, are responsible for more than 500000 deaths annually. They include African and American trypanosomiasis, leishmaniasis, malaria, toxoplasmosis, and amoebiasis. Mechanisms underlying invasion of the brain parenchyma by protozoa are not well understood and may depend on parasite nature: a vascular invasion route is most common. Immunosuppression favors parasite invasion into the CNS and therefore the host immune response plays a pivotal role in the development of a neuropathology in these infectious diseases. In the brain, microglia are the resident immune cells active in defense against pathogens that target the CNS. Beside their direct role in innate immunity, they also play a principal role in coordinating the trafficking and recruitment of other immune cells from the periphery to the CNS. Despite their evident involvement in the neuropathology of protozoan infections, little attention has given to microglia-parasite interactions. This review describes the most prominent features of microglial cells and protozoan parasites and summarizes the most recent information regarding the reaction of microglial cells to parasitic infections. We highlight the involvement of the periphery-brain axis and emphasize possible scenarios for microglia-parasite interactions.
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Affiliation(s)
- Katherine Figarella
- Institute of Physiology, Department of Neurophysiology, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Hartwig Wolburg
- Institute of Pathology and Neuropathology, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Olga Garaschuk
- Institute of Physiology, Department of Neurophysiology, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Michael Duszenko
- Institute of Physiology, Department of Neurophysiology, Eberhard Karls University of Tübingen, Tübingen, Germany
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31
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Lennartz F, Smith C, Craig AG, Higgins MK. Structural insights into diverse modes of ICAM-1 binding by Plasmodium falciparum-infected erythrocytes. Proc Natl Acad Sci U S A 2019; 116:20124-20134. [PMID: 31527263 PMCID: PMC6778195 DOI: 10.1073/pnas.1911900116] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
A major determinant of pathogenicity in malaria caused by Plasmodium falciparum is the adhesion of parasite-infected erythrocytes to the vasculature or tissues of infected individuals. This occludes blood flow, leads to inflammation, and increases parasitemia by reducing spleen-mediated clearance of the parasite. This adhesion is mediated by PfEMP1, a multivariant family of around 60 proteins per parasite genome which interact with specific host receptors. One of the most common of these receptors is intracellular adhesion molecule-1 (ICAM-1), which is bound by 2 distinct groups of PfEMP1, A-type and B or C (BC)-type. Here, we present the structure of a domain from a B-type PfEMP1 bound to ICAM-1, revealing a complex binding site. Comparison with the existing structure of an A-type PfEMP1 bound to ICAM-1 shows that the 2 complexes share a globally similar architecture. However, while the A-type PfEMP1 bind ICAM-1 through a highly conserved binding surface, the BC-type PfEMP1 use a binding site that is more diverse in sequence, similar to how PfEMP1 interact with other human receptors. We also show that A- and BC-type PfEMP1 present ICAM-1 at different angles, perhaps influencing the ability of neighboring PfEMP1 domains to bind additional receptors. This illustrates the deep diversity of the PfEMP1 and demonstrates how variations in a single domain architecture can modulate binding to a specific ligand to control function and facilitate immune evasion.
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Affiliation(s)
- Frank Lennartz
- Department of Biochemistry, University of Oxford, OX1 3QU Oxford, United Kingdom
| | - Cameron Smith
- Department of Biochemistry, University of Oxford, OX1 3QU Oxford, United Kingdom
| | - Alister G Craig
- Liverpool School of Tropical Medicine, L3 5QA Liverpool, United Kingdom
| | - Matthew K Higgins
- Department of Biochemistry, University of Oxford, OX1 3QU Oxford, United Kingdom;
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32
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Abstract
PURPOSE OF REVIEW Activated protein C (APC) is a homeostatic coagulation protease with anticoagulant and cytoprotective activities. Focusing on APC's effects in the brain, this review discusses three different scenarios that illustrate how APC functions are intimately affecting the physiology and pathophysiology of the brain. RECENT FINDINGS Cytoprotective APC therapy holds promise for the treatment of ischemic stroke, and a recently completed trial suggested that cytoprotective-selective 3K3A-APC reduced bleeding in ischemic stroke patients. In contrast, APC's anticoagulant activity contributes to brain bleeding as shown by the disproportional upregulation of APC generation in cerebral cavernous malformations lesions in mice. However, too little APC generation also contributes to maladies of the brain, such as in case of cerebral malaria where the binding of infected erythrocytes to the endothelial protein C receptor (EPCR) may interfere with the EPCR-dependent functions of the protein C pathway. Furthermore, discoveries of new activities of APC such as the inhibition of the NLRP3-mediated inflammasome and of new applications of APC therapy such as in Alzheimer's disease and graft-versus-host disease continue to advance our knowledge of this important proteolytic regulatory system. SUMMARY APC's many activities or lack thereof are intimately involved in multiple neuropathologies, providing abundant opportunities for translational research.
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