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Najer A, Kim J, Saunders C, Che J, Baum J, Stevens MM. Enhanced Antimalarial and Antisequestration Activity of Methoxybenzenesulfonate-Modified Biopolymers and Nanoparticles for Tackling Severe Malaria. ACS Infect Dis 2024; 10:732-745. [PMID: 38271991 PMCID: PMC10862538 DOI: 10.1021/acsinfecdis.3c00564] [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: 10/20/2023] [Revised: 01/07/2024] [Accepted: 01/08/2024] [Indexed: 01/27/2024]
Abstract
Severe malaria is a life-threatening condition that is associated with a high mortality. Severe Plasmodium falciparum infections are mediated primarily by high parasitemia and binding of infected red blood cells (iRBCs) to the blood vessel endothelial layer, a process known as sequestration. Here, we show that including the 5-amino-2-methoxybenzenesulfonate (AMBS) chemical modification in soluble biopolymers (polyglutamic acid and heparin) and poly(acrylic acid)-exposing nanoparticles serves as a universal tool to introduce a potent parasite invasion inhibitory function in these materials. Importantly, the modification did not add or eliminated (for heparin) undesired anticoagulation activity. The materials protected RBCs from invasion by various parasite strains, employing both major entry pathways. Two further P. falciparum strains, which either expose ligands for chondroitin sulfate A (CSA) or intercellular adhesion molecule 1 (ICAM-1) on iRBCs, were tested in antisequestration assays due to their relevance in placental and cerebral malaria, respectively. Antisequestration activity was found to be more efficacious with nanoparticles vs gold-standard soluble biopolymers (CSA and heparin) against both strains, when tested on receptor-coated dishes. The nanoparticles also efficiently inhibited and reversed the sequestration of iRBCs on endothelial cells. First, the materials described herein have the potential to reduce the parasite burden by acting at the key multiplication stage of reinvasion. Second, the antisequestration ability could help remove iRBCs from the blood vessel endothelium, which could otherwise cause vessel obstruction, which in turn can lead to multiple organ failure in severe malaria infections. This approach represents a further step toward creation of adjunctive therapies for this devastating condition to reduce morbidity and mortality.
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Affiliation(s)
- Adrian Najer
- Department
of Materials, Department of Bioengineering, and Institute of Biomedical
Engineering, Imperial College London, London SW7 2AZ, U.K.
- Department
of Life Sciences, Imperial College London, London SW7 2AZ, U.K.
| | - Junyoung Kim
- Department
of Materials, Department of Bioengineering, and Institute of Biomedical
Engineering, Imperial College London, London SW7 2AZ, U.K.
| | - Catherine Saunders
- Department
of Materials, Department of Bioengineering, and Institute of Biomedical
Engineering, Imperial College London, London SW7 2AZ, U.K.
| | - Junyi Che
- Department
of Materials, Department of Bioengineering, and Institute of Biomedical
Engineering, Imperial College London, London SW7 2AZ, U.K.
| | - Jake Baum
- Department
of Life Sciences, Imperial College London, London SW7 2AZ, U.K.
| | - Molly M. Stevens
- Department
of Materials, Department of Bioengineering, and Institute of Biomedical
Engineering, Imperial College London, London SW7 2AZ, U.K.
- Department
of Physiology, Anatomy and Genetics, Department of Engineering Science,
and Kavli Institute for Nanoscience Discovery, University of Oxford, Oxford OX1 3QU, U.K.
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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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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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4
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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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Oleinikov AV. High-Throughput BioPlex Assay for the Study of Functionally Active Plasmodium Falciparum Antigens That Are Expressed on the Surface of Infected Erythrocytes. Methods Mol Biol 2022; 2470:327-342. [PMID: 35881356 DOI: 10.1007/978-1-0716-2189-9_24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Identification of P. falciparum infected erythrocyte surface ligands (such as PfEMP1) matched with the host receptors they interact with, as well as identification of PfEMP1 domains that are targets of protective immunity, are important for understanding of the pathophysiology of severe malaria (SM) and for design of novel vaccine candidates. In addition, identification of small-molecule drugs that can prevent or reverse receptor-ligand domain interactions could provide new tools for adjunctive therapy in SM. This protocol describes how to prepare functionally intact PfEMP1 proteins in mammalian cells (COS-7) and immobilize them on the surface of BioPlex beads. Furthermore, the protocol described how to identify PfEMP1 constructs that bind to specific host receptors or to immunoglobulins (IgG, IgM, etc.), and how to measure inhibition of the receptor binding to PfEMP1 constructs by small-molecule compounds or serum/plasma.
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Affiliation(s)
- Andrew V Oleinikov
- Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, USA.
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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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Badaut C, Visitdesotrakul P, Chabry A, Bigey P, Tornyigah B, Roman J, Maroufou JA, Amoussou A, Ayivi BS, Sagbo G, Ndam NT, Oleinikov AV, Tahar R. IgG acquisition against PfEMP1 PF11_0521 domain cassette DC13, DBLβ3_D4 domain, and peptides located within these constructs in children with cerebral malaria. Sci Rep 2021; 11:3680. [PMID: 33574457 PMCID: PMC7878510 DOI: 10.1038/s41598-021-82444-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 12/30/2020] [Indexed: 11/09/2022] Open
Abstract
The Plasmodium falciparum erythrocyte-membrane-protein-1 (PF3D7_1150400/PF11_0521) contains both domain cassette DC13 and DBLβ3 domain binding to EPCR and ICAM-1 receptors, respectively. This type of PfEMP1 proteins with dual binding specificity mediate specific interactions with brain micro-vessels endothelium leading to the development of cerebral malaria (CM). Using plasma collected from children at time of hospital admission and after 30 days, we study an acquisition of IgG response to PF3D7_1150400/PF11_0521 DC13 and DBLβ3_D4 recombinant constructs, and five peptides located within these constructs, specifically in DBLα1.7_D2 and DBLβ3_D4 domains. We found significant IgG responses against the entire DC13, PF11_0521_DBLβ3_D4 domain, and peptides. The responses varied against different peptides and depended on the clinical status of children. The response was stronger at day 30, and mostly did not differ between CM and uncomplicated malaria (UM) groups. Specifically, the DBLβ3 B3-34 peptide that contains essential residues involved in the interaction between PF11_0521 DBLβ3_D4 domain and ICAM-1 receptor demonstrated significant increase in reactivity to IgG1 and IgG3 antibodies at convalescence. Further, IgG reactivity in CM group at time of admission against functionally active (ICAM-1-binding) PF11_0521 DBLβ3_D4 domain was associated with protection against severe anemia. These results support development of vaccine based on the PF3D7_1150400/PF11_0521 structures to prevent CM.
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Affiliation(s)
- Cyril Badaut
- Institut de Recherche Biomédicale des Armées, National Reference Laboratory for Arboviruses, Marseille, France
| | | | | | - Pascal Bigey
- Université de Paris, UMR 8151 CNRS - INSERM U1022 - ENSCP, 75006, Paris, France
| | | | | | - Jules Alao Maroufou
- Département de Pédiatrie, Hôpital Mère-Enfant La Lagune (CHUMEL) Cotonou, Cotonou, Benin
| | - Annick Amoussou
- Service de Pédiatrie, Centre Hospitalo-Universitaire, Suruléré (CHU-Suruléré, Cotonou, Benin
| | - Blaise Serge Ayivi
- Service de Pédiatrie, Centre National Hospitalo-Universitaire (CNHU), Cotonou, Benin
| | - Gratien Sagbo
- Service de Pédiatrie, Centre National Hospitalo-Universitaire (CNHU), Cotonou, Benin
| | | | - Andrew V Oleinikov
- Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, 33428, USA
| | - Rachida Tahar
- Université de Paris, MERIT, IRD, 75006, Paris, France. .,Institut de Recherche Pour le Développement (IRD), UMR 261 Mère et Enfant Face Aux Infections Tropicales, Université Paris-Descartes, 4, Avenue de l'observatoire, 75270, Paris, France.
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8
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Padilla A, Dovell S, Chesnokov O, Hoggard M, Oleinikov AV, Marí F. Conus venom fractions inhibit the adhesion of Plasmodium falciparum erythrocyte membrane protein 1 domains to the host vascular receptors. J Proteomics 2020; 234:104083. [PMID: 33373718 DOI: 10.1016/j.jprot.2020.104083] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 11/28/2020] [Accepted: 12/20/2020] [Indexed: 11/16/2022]
Abstract
Using high-throughput BioPlex assays, we determined that six fractions from the venom of Conus nux inhibit the adhesion of various recombinant PfEMP-1 protein domains (PF08_0106 CIDR1α3.1, PF11_0521 DBL2β3, and PFL0030c DBL3X and DBL5e) to their corresponding receptors (CD36, ICAM-1, and CSA, respectively). The protein domain-receptor interactions permit P. falciparum-infected erythrocytes (IE) to evade elimination in the spleen by adhering to the microvasculature in various organs including the placenta. The sequences for the main components of the fractions, determined by tandem mass spectrometry, yielded four T-superfamily conotoxins, one (CC-Loop-CC) with I-IV, II-III connectivity and three (CC-Loop-CXaaC) with a I-III, II-IV connectivity. The 3D structure for one of the latter, NuxVA = GCCPAPLTCHCVIY, revealed a novel scaffold defined by double turns forming a hairpin-like structure stabilized by the two disulfide bonds. Two other main fraction components were a miniM conotoxin, and a O2-superfamily conotoxin with cysteine framework VI/VII. This study is the first one of its kind suggesting the use of conotoxins for developing pharmacological tools for anti-adhesion adjunct therapy against malaria. Similarly, mitigation of emerging diseases like AIDS and COVID-19, can also benefit from conotoxins as inhibitors of protein-protein interactions as treatment. BIOLOGICAL SIGNIFICANCE: Among the 850+ species of cone snail species there are hundreds of thousands of diverse venom exopeptides that have been selected throughout several million years of evolution to capture prey and deter predators. They do so by targeting several surface proteins present in target excitable cells. This immense biomolecular library of conopeptides can be explored for potential use as therapeutic leads against persistent and emerging diseases affecting non-excitable systems. We aim to expand the pharmacological reach of conotoxins/conopeptides by revealing their in vitro capacity to disrupt protein-protein and protein-polysaccharide interactions that directly contribute to pathology of Plasmodium falciparum malaria. This is significant for severe forms of malaria, which might be deadly even after treated with current parasite-killing drugs because of persistent cytoadhesion of P. falciparum infected erythrocytes even when parasites within red blood cells are dead. Anti-adhesion adjunct drugs would de-sequester or prevent additional sequestration of infected erythrocytes and may significantly improve survival of malaria patients. These results provide a lead for further investigations into conotoxins and other venom peptides as potential candidates for anti-adhesion or blockade-therapies. This study is the first of its kind and it suggests that conotoxins can be developed as pharmacological tools for anti-adhesion adjunct therapy against malaria. Similarly, mitigation of emerging diseases like AIDS and COVID-19, can also benefit from conotoxins as potential inhibitors of protein-protein interactions as treatment.
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Affiliation(s)
- Alberto Padilla
- Department of Biological Sciences, Florida Atlantic University, 777 Glades Rd, Boca Raton, FL 33431, USA
| | - Sanaz Dovell
- Department of Chemistry & Biochemistry, Florida Atlantic University, 777 Glades Rd, Boca Raton, FL 33431, USA
| | - Olga Chesnokov
- Department of Biomedical Science, Florida Atlantic University, 777 Glades Rd, Boca Raton, FL 33431, USA
| | - Mickelene Hoggard
- Chemical Sciences Division, Hollings Marine Laboratory, National Institute of Standards and Technology, 331 Fort Johnson Road, Charleston, SC 29412, USA
| | - Andrew V Oleinikov
- Department of Biomedical Science, Florida Atlantic University, 777 Glades Rd, Boca Raton, FL 33431, USA.
| | - Frank Marí
- Chemical Sciences Division, Hollings Marine Laboratory, National Institute of Standards and Technology, 331 Fort Johnson Road, Charleston, SC 29412, USA.
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9
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Liu J, Mosavati B, Oleinikov AV, Du E. Biosensors for Detection of Human Placental Pathologies: A Review of Emerging Technologies and Current Trends. Transl Res 2019; 213:23-49. [PMID: 31170377 PMCID: PMC6783355 DOI: 10.1016/j.trsl.2019.05.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 05/13/2019] [Accepted: 05/14/2019] [Indexed: 02/06/2023]
Abstract
Substantial growth in the biosensor research has enabled novel, sensitive and point-of-care diagnosis of human diseases in the last decade. This paper presents an overview of the research in the field of biosensors that can potentially predict and diagnosis of common placental pathologies. A survey of biomarkers in maternal circulation and their characterization methods is presented, including markers of oxidative stress, angiogenic factors, placental debris, and inflammatory biomarkers that are associated with various pathophysiological processes in the context of pregnancy complications. Novel biosensors enabled by microfluidics technology and nanomaterials is then reviewed. Representative designs of plasmonic and electrochemical biosensors for highly sensitive and multiplexed detection of biomarkers, as well as on-chip sample preparation and sensing for automatic biomarker detection are illustrated. New trends in organ-on-a-chip based placental disease models are highlighted to illustrate the capability of these in vitro disease models in better understanding the complex pathophysiological processes, including mass transfer across the placental barrier, oxidative stress, inflammation, and malaria infection. Biosensor technologies that can be potentially embedded in the placental models for real time, label-free monitoring of these processes and events are suggested. Merger of cell culture in microfluidics and biosensing can provide significant potential for new developments in advanced placental models, and tools for diagnosis, drug screening and efficacy testing.
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Affiliation(s)
- Jia Liu
- College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering, Florida Atlantic University, Boca Raton, Florida
| | - Babak Mosavati
- College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering, Florida Atlantic University, Boca Raton, Florida
| | - Andrew V Oleinikov
- Charles E. Schmidt College of Medicine, Department of Biomedical Science, Florida Atlantic University, Boca Raton, Florida
| | - E Du
- College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering, Florida Atlantic University, Boca Raton, Florida; Charles E. Schmidt College of Science, Department of Biological Sciences, Florida Atlantic University, Boca Raton, Florida.
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10
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Chesnokov O, Merritt J, Tcherniuk SO, Milman N, Oleinikov AV. Plasmodium falciparum infected erythrocytes can bind to host receptors integrins αVβ3 and αVβ6 through DBLδ1_D4 domain of PFL2665c PfEMP1 protein. Sci Rep 2018; 8:17871. [PMID: 30552383 PMCID: PMC6294747 DOI: 10.1038/s41598-018-36071-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Accepted: 11/14/2018] [Indexed: 02/05/2023] Open
Abstract
Major complications and mortality from Plasmodium falciparum malaria are associated with cytoadhesion of parasite-infected erythrocytes (IE). The main parasite ligands for cytoadhesion are members of the P. falciparum erythrocyte membrane protein 1 (PfEMP1) family. Interactions of different host receptor-ligand pairs may lead to various pathological outcomes, like placental or cerebral malaria. It has been shown previously that IE can bind integrin αVβ3. Using bead-immobilized PfEMP1 constructs, we have identified that the PFL2665c DBLδ1_D4 domain binds to αVβ3 and αVβ6. A parasite line expressing PFL2665c binds to surface-immobilized αVβ3 and αVβ6; both are RGD motif-binding integrins. Interactions can be inhibited by cyloRGDFV peptide, an antagonist of RGD-binding integrins. This is a first, to the best of our knowledge, implication of a specific PfEMP1 domain for binding to integrins. These host receptors have important physiological functions in endothelial and immune cells; therefore, these results will contribute to future studies and a better understanding, at the molecular level, of the physiological outcome of interactions between IE and integrin receptors on the surface of host cells.
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Affiliation(s)
- Olga Chesnokov
- Charles E. Schmidt College of Medicine, Department of Biomedical Science, Florida Atlantic University, Boca Raton, FL, USA
| | - Jordan Merritt
- Charles E. Schmidt College of Medicine, Department of Biomedical Science, Florida Atlantic University, Boca Raton, FL, USA
| | - Sergey O Tcherniuk
- Charles E. Schmidt College of Medicine, Department of Biomedical Science, Florida Atlantic University, Boca Raton, FL, USA
| | - Neta Milman
- Seattle Biomedical Research Institute, Seattle, WA, USA
| | - Andrew V Oleinikov
- Charles E. Schmidt College of Medicine, Department of Biomedical Science, Florida Atlantic University, Boca Raton, FL, USA.
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Rosette-Disrupting Effect of an Anti-Plasmodial Compound for the Potential Treatment of Plasmodium falciparum Malaria Complications. Sci Rep 2016; 6:29317. [PMID: 27403804 PMCID: PMC4941523 DOI: 10.1038/srep29317] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Accepted: 06/14/2016] [Indexed: 11/16/2022] Open
Abstract
The spread of artemisinin-resistant parasites could lead to higher incidence of patients with malaria complications. However, there are no current treatments that directly dislodge sequestered parasites from the microvasculature. We show that four common antiplasmodial drugs do not disperse rosettes (erythrocyte clusters formed by malaria parasites) and therefore develop a cell-based high-throughput assay to identify potential rosette-disrupting compounds. A pilot screen of 2693 compounds identified Malaria Box compound MMV006764 as a potential candidate. Although it reduced rosetting by a modest 20%, MMV006764 was validated to be similarly effective against both blood group O and A rosettes of three laboratory parasite lines. Coupled with its antiplasmodial activity and drug-likeness, MMV006764 represents the first small-molecule compound that disrupts rosetting and could potentially be used in a resource-limited setting to treat patients deteriorating rapidly from malaria complications. Such dual-action drugs that simultaneously restore microcirculation and reduce parasite load could significantly reduce malaria morbidity and mortality.
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Malaria Parasite Proteins and Their Role in Alteration of the Structure and Function of Red Blood Cells. ADVANCES IN PARASITOLOGY 2015; 91:1-86. [PMID: 27015947 DOI: 10.1016/bs.apar.2015.09.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Malaria, caused by Plasmodium spp., continues to be a major threat to human health and a significant cause of socioeconomic hardship in many countries. Almost half of the world's population live in malaria-endemic regions and many of them suffer one or more, often life-threatening episodes of malaria every year, the symptoms of which are attributable to replication of the parasite within red blood cells (RBCs). In the case of Plasmodium falciparum, the species responsible for most malaria-related deaths, parasite replication within RBCs is accompanied by striking alterations to the morphological, biochemical and biophysical properties of the host cell that are essential for the parasites' survival. To achieve this, the parasite establishes a unique and extensive protein export network in the infected RBC, dedicating at least 6% of its genome to the process. Understanding the full gamut of proteins involved in this process and the mechanisms by which P. falciparum alters the structure and function of RBCs is important both for a more complete understanding of the pathogenesis of malaria and for development of new therapeutic strategies to prevent or treat this devastating disease. This review focuses on what is currently known about exported parasite proteins, their interactions with the RBC and their likely pathophysiological consequences.
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