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Lee SK, Nguyen TK, Mohring F, Han JH, Firdaus ER, Na SH, Park WS, Moon RW, Han ET. Merozoite surface protein 1 paralog is involved in the human erythrocyte invasion of a zoonotic malaria, Plasmodium knowlesi. Front Cell Infect Microbiol 2023; 13:1314533. [PMID: 38111629 PMCID: PMC10726050 DOI: 10.3389/fcimb.2023.1314533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Accepted: 11/15/2023] [Indexed: 12/20/2023] Open
Abstract
The zoonotic malaria parasite Plasmodium knowlesi is an important public health concern in Southeast Asia. Invasion of host erythrocytes is essential for parasite growth, and thus, understanding the repertoire of parasite proteins that enable this process is vital for identifying vaccine candidates and how some species are able to cause zoonotic infection. Merozoite surface protein 1 (MSP1) is found in all malaria parasite species and is perhaps the most well-studied as a potential vaccine candidate. While MSP1 is encoded by a single gene in P. falciparum, all other human infective species (P. vivax, P. knowlesi, P. ovale, and P. malariae) additionally encode a divergent paralogue known as MSP1P, and little is known about its role or potential functional redundancy with MSP1. We, therefore, studied the function of P. knowlesi merozoite surface protein 1 paralog (PkMSP1P), using both recombinant protein and CRISPR-Cas9 genome editing. The recombinant 19-kDa C-terminus of PkMSP1P (PkMSP1P-19) was shown to bind specifically to human reticulocytes. However, immunoblotting data suggested that PkMSP1P-19-induced antibodies can recognize PkMSP1-19 and vice versa, confounding our ability to separate the properties of these two proteins. Targeted disruption of the pkmsp1p gene profoundly impacts parasite growth, demonstrating for the first time that PkMSP1P is important in in vitro growth of P. knowlesi and likely plays a distinct role from PkMSP1. Importantly, the MSP1P KO also enabled functional characterization of the PkMSP1P-19 antibodies, revealing clear immune cross-reactivity between the two paralogues, highlighting the vital importance of genetic studies in contextualizing recombinant protein studies.
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Affiliation(s)
- Seong-Kyun Lee
- Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon, Gangwon-do, Republic of Korea
| | - Tuyet Kha Nguyen
- Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon, Gangwon-do, Republic of Korea
| | - Franziska Mohring
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Jin-Hee Han
- Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon, Gangwon-do, Republic of Korea
| | - Egy Rahman Firdaus
- Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon, Gangwon-do, Republic of Korea
| | - Sung-Hun Na
- Department of Obstetrics and Gynecology, School of Medicine, Kangwon National University, Chuncheon, Gangwon-do, Republic of Korea
| | - Won-Sun Park
- Department of Physiology, School of Medicine, Kangwon National University, Chuncheon, Gangwon-do, Republic of Korea
| | - Robert W. Moon
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Eun-Taek Han
- Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon, Gangwon-do, Republic of Korea
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2
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Hart MN, Mohring F, DonVito SM, Thomas JA, Muller-Sienerth N, Wright GJ, Knuepfer E, Saibil HR, Moon RW. Sequential roles for red blood cell binding proteins enable phased commitment to invasion for malaria parasites. Nat Commun 2023; 14:4619. [PMID: 37528099 PMCID: PMC10393984 DOI: 10.1038/s41467-023-40357-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 07/20/2023] [Indexed: 08/03/2023] Open
Abstract
Invasion of red blood cells (RBCs) by Plasmodium merozoites is critical to their continued survival within the host. Two major protein families, the Duffy binding-like proteins (DBPs/EBAs) and the reticulocyte binding like proteins (RBLs/RHs) have been studied extensively in P. falciparum and are hypothesized to have overlapping, but critical roles just prior to host cell entry. The zoonotic malaria parasite, P. knowlesi, has larger invasive merozoites and contains a smaller, less redundant, DBP and RBL repertoire than P. falciparum. One DBP (DBPα) and one RBL, normocyte binding protein Xa (NBPXa) are essential for invasion of human RBCs. Taking advantage of the unique biological features of P. knowlesi and iterative CRISPR-Cas9 genome editing, we determine the precise order of key invasion milestones and demonstrate distinct roles for each family. These distinct roles support a mechanism for phased commitment to invasion and can be targeted synergistically with invasion inhibitory antibodies.
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Affiliation(s)
- Melissa N Hart
- Department of Infection Biology, Faculty of Infectious and Tropical Disease, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK
- Department of Pathobiology and Population Sciences, Royal Veterinary College, Hawkshead Lane, Hatfield, AL9 7TA, UK
| | - Franziska Mohring
- Department of Infection Biology, Faculty of Infectious and Tropical Disease, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK
| | - Sophia M DonVito
- Department of Infection Biology, Faculty of Infectious and Tropical Disease, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK
| | - James A Thomas
- Department of Infection Biology, Faculty of Infectious and Tropical Disease, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK
| | | | - Gavin J Wright
- Wellcome Sanger Institute, Hinxton, Cambridge, CB10 1SA, UK
- Department of Biology, Hull York Medical School, York Biomedical Research Institute, University of York, Wentworth Way, York, YO10 5DD, UK
| | - Ellen Knuepfer
- Department of Pathobiology and Population Sciences, Royal Veterinary College, Hawkshead Lane, Hatfield, AL9 7TA, UK
- Malaria Parasitology Laboratory, Francis Crick Institute, London, NW1 1AT, UK
| | - Helen R Saibil
- ISMB, Biological Sciences, Birkbeck, University of London, Malet St, London, WC1E 7HX, UK
| | - Robert W Moon
- Department of Infection Biology, Faculty of Infectious and Tropical Disease, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK.
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Hou MM, Barrett JR, Themistocleous Y, Rawlinson TA, Diouf A, Martinez FJ, Nielsen CM, Lias AM, King LDW, Edwards NJ, Greenwood NM, Kingham L, Poulton ID, Khozoee B, Goh C, Hodgson SH, Mac Lochlainn DJ, Salkeld J, Guillotte-Blisnick M, Huon C, Mohring F, Reimer JM, Chauhan VS, Mukherjee P, Biswas S, Taylor IJ, Lawrie AM, Cho JS, Nugent FL, Long CA, Moon RW, Miura K, Silk SE, Chitnis CE, Minassian AM, Draper SJ. Vaccination with Plasmodium vivax Duffy-binding protein inhibits parasite growth during controlled human malaria infection. Sci Transl Med 2023; 15:eadf1782. [PMID: 37437014 PMCID: PMC7615121 DOI: 10.1126/scitranslmed.adf1782] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Accepted: 06/05/2023] [Indexed: 07/14/2023]
Abstract
There are no licensed vaccines against Plasmodium vivax. We conducted two phase 1/2a clinical trials to assess two vaccines targeting P. vivax Duffy-binding protein region II (PvDBPII). Recombinant viral vaccines using chimpanzee adenovirus 63 (ChAd63) and modified vaccinia virus Ankara (MVA) vectors as well as a protein and adjuvant formulation (PvDBPII/Matrix-M) were tested in both a standard and a delayed dosing regimen. Volunteers underwent controlled human malaria infection (CHMI) after their last vaccination, alongside unvaccinated controls. Efficacy was assessed by comparisons of parasite multiplication rates in the blood. PvDBPII/Matrix-M, given in a delayed dosing regimen, elicited the highest antibody responses and reduced the mean parasite multiplication rate after CHMI by 51% (n = 6) compared with unvaccinated controls (n = 13), whereas no other vaccine or regimen affected parasite growth. Both viral-vectored and protein vaccines were well tolerated and elicited expected, short-lived adverse events. Together, these results support further clinical evaluation of the PvDBPII/Matrix-M P. vivax vaccine.
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Affiliation(s)
- Mimi M Hou
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
- Jenner Institute, University of Oxford, Oxford OX3 7DQ, UK
- Kavli Institute for Nanoscience Discovery, University of Oxford, Oxford OX1 3QU, UK
| | - Jordan R Barrett
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
- Jenner Institute, University of Oxford, Oxford OX3 7DQ, UK
- Kavli Institute for Nanoscience Discovery, University of Oxford, Oxford OX1 3QU, UK
| | | | | | - Ababacar Diouf
- Laboratory of Malaria and Vector Research, NIAID/NIH, Rockville, MD 20852, USA
| | - Francisco J Martinez
- Unité de Biologie de Plasmodium et Vaccins, Institut Pasteur, Université Paris Cité, 25-28 Rue du Dr Roux, 75015 Paris, France
| | - Carolyn M Nielsen
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
- Jenner Institute, University of Oxford, Oxford OX3 7DQ, UK
- Kavli Institute for Nanoscience Discovery, University of Oxford, Oxford OX1 3QU, UK
| | - Amelia M Lias
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
- Jenner Institute, University of Oxford, Oxford OX3 7DQ, UK
- Kavli Institute for Nanoscience Discovery, University of Oxford, Oxford OX1 3QU, UK
| | - Lloyd D W King
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
- Jenner Institute, University of Oxford, Oxford OX3 7DQ, UK
- Kavli Institute for Nanoscience Discovery, University of Oxford, Oxford OX1 3QU, UK
| | - Nick J Edwards
- Jenner Institute, University of Oxford, Oxford OX3 7DQ, UK
| | | | - Lucy Kingham
- Jenner Institute, University of Oxford, Oxford OX3 7DQ, UK
| | - Ian D Poulton
- Jenner Institute, University of Oxford, Oxford OX3 7DQ, UK
| | | | - Cyndi Goh
- Jenner Institute, University of Oxford, Oxford OX3 7DQ, UK
| | - Susanne H Hodgson
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
- Jenner Institute, University of Oxford, Oxford OX3 7DQ, UK
- Kavli Institute for Nanoscience Discovery, University of Oxford, Oxford OX1 3QU, UK
| | - Dylan J Mac Lochlainn
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
- Jenner Institute, University of Oxford, Oxford OX3 7DQ, UK
- Kavli Institute for Nanoscience Discovery, University of Oxford, Oxford OX1 3QU, UK
| | - Jo Salkeld
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
- Jenner Institute, University of Oxford, Oxford OX3 7DQ, UK
- Kavli Institute for Nanoscience Discovery, University of Oxford, Oxford OX1 3QU, UK
| | - Micheline Guillotte-Blisnick
- Unité de Biologie de Plasmodium et Vaccins, Institut Pasteur, Université Paris Cité, 25-28 Rue du Dr Roux, 75015 Paris, France
| | - Christèle Huon
- Unité de Biologie de Plasmodium et Vaccins, Institut Pasteur, Université Paris Cité, 25-28 Rue du Dr Roux, 75015 Paris, France
| | - Franziska Mohring
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London WC1E 7HT, UK
| | | | - Virander S Chauhan
- International Centre for Genetic Engineering and Biotechnology (ICGEB), New Delhi, India
| | | | - Sumi Biswas
- Jenner Institute, University of Oxford, Oxford OX3 7DQ, UK
| | - Iona J Taylor
- Jenner Institute, University of Oxford, Oxford OX3 7DQ, UK
| | | | - Jee-Sun Cho
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
- Jenner Institute, University of Oxford, Oxford OX3 7DQ, UK
- Kavli Institute for Nanoscience Discovery, University of Oxford, Oxford OX1 3QU, UK
| | - Fay L Nugent
- Jenner Institute, University of Oxford, Oxford OX3 7DQ, UK
| | - Carole A Long
- Laboratory of Malaria and Vector Research, NIAID/NIH, Rockville, MD 20852, USA
| | - Robert W Moon
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London WC1E 7HT, UK
| | - Kazutoyo Miura
- Laboratory of Malaria and Vector Research, NIAID/NIH, Rockville, MD 20852, USA
| | - Sarah E Silk
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
- Jenner Institute, University of Oxford, Oxford OX3 7DQ, UK
- Kavli Institute for Nanoscience Discovery, University of Oxford, Oxford OX1 3QU, UK
| | - Chetan E Chitnis
- Unité de Biologie de Plasmodium et Vaccins, Institut Pasteur, Université Paris Cité, 25-28 Rue du Dr Roux, 75015 Paris, France
| | - Angela M Minassian
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
- Jenner Institute, University of Oxford, Oxford OX3 7DQ, UK
- Kavli Institute for Nanoscience Discovery, University of Oxford, Oxford OX1 3QU, UK
- NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Simon J Draper
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
- Jenner Institute, University of Oxford, Oxford OX3 7DQ, UK
- Kavli Institute for Nanoscience Discovery, University of Oxford, Oxford OX1 3QU, UK
- NIHR Oxford Biomedical Research Centre, Oxford, UK
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Moskovitz R, Pholcharee T, DonVito SM, Guloglu B, Lowe E, Mohring F, Moon RW, Higgins MK. Structural basis for DARC binding in reticulocyte invasion by Plasmodium vivax. Nat Commun 2023; 14:3637. [PMID: 37336887 DOI: 10.1038/s41467-023-39357-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Accepted: 06/06/2023] [Indexed: 06/21/2023] Open
Abstract
The symptoms of malaria occur during the blood stage of infection, when the parasite replicates within human red blood cells. The human malaria parasite, Plasmodium vivax, selectively invades reticulocytes in a process which requires an interaction between the ectodomain of the human DARC receptor and the Plasmodium vivax Duffy-binding protein, PvDBP. Previous studies have revealed that a small helical peptide from DARC binds to region II of PvDBP (PvDBP-RII). However, it is also known that sulphation of tyrosine residues on DARC affects its binding to PvDBP and these residues were not observed in previous structures. We therefore present the structure of PvDBP-RII bound to sulphated DARC peptide, showing that a sulphate on tyrosine 41 binds to a charged pocket on PvDBP-RII. We use molecular dynamics simulations, affinity measurements and growth-inhibition experiments in parasites to confirm the importance of this interaction. We also reveal the epitope for vaccine-elicited growth-inhibitory antibody DB1. This provides a complete understanding of the binding of PvDBP-RII to DARC and will guide the design of vaccines and therapeutics to target this essential interaction.
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Affiliation(s)
- Re'em Moskovitz
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK
| | - Tossapol Pholcharee
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK
| | - Sophia M DonVito
- London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Bora Guloglu
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK
| | - Edward Lowe
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK
| | - Franziska Mohring
- London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Robert W Moon
- London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Matthew K Higgins
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK.
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5
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Mohring F, van Schalkwyk DA, Henrici RC, Blasco B, Leroy D, Sutherland CJ, Moon RW. Cation ATPase (ATP4) Orthologue Replacement in the Malaria Parasite Plasmodium knowlesi Reveals Species-Specific Responses to ATP4-Targeting Drugs. mBio 2022; 13:e0117822. [PMID: 36190127 PMCID: PMC9600963 DOI: 10.1128/mbio.01178-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 08/31/2022] [Indexed: 11/30/2022] Open
Abstract
Several unrelated classes of antimalarial compounds developed against Plasmodium falciparum target a parasite-specific P-type ATP-dependent Na+ pump, PfATP4. We have previously shown that other malaria parasite species infecting humans are less susceptible to these compounds. Here, we generated a series of transgenic Plasmodium knowlesi orthologue replacement (OR) lines in which the endogenous pkatp4 locus was replaced by a recodonized P. knowlesi atp4 (pkatp4) coding region or the orthologous coding region from P. falciparum, Plasmodium malariae, Plasmodium ovale subsp. curtisi, or Plasmodium vivax. Each OR transgenic line displayed a similar growth pattern to the parental P. knowlesi line. We found significant orthologue-specific differences in parasite susceptibility to three chemically unrelated ATP4 inhibitors, but not to comparator drugs, among the P. knowlesi OR lines. The PfATP4OR transgenic line of P. knowlesi was significantly more susceptible than our control PkATP4OR line to three ATP4 inhibitors: cipargamin, PA21A092, and SJ733. The PvATP4OR and PmATP4OR lines were similarly susceptible to the control PkATP4OR line, but the PocATP4OR line was significantly less susceptible to all ATP4 inhibitors than the PkATP4OR line. Cipargamin-induced inhibition of Na+ efflux was also significantly greater with the P. falciparum orthologue of ATP4. This confirms that species-specific susceptibility differences previously observed in ex vivo studies of human isolates are partly or wholly enshrined in the primary amino acid sequences of the respective ATP4 orthologues and highlights the need to monitor efficacy of investigational malaria drugs against multiple species. P. knowlesi is now established as an important in vitro model for studying drug susceptibility in non-falciparum malaria parasites. IMPORTANCE Effective drugs are vital to minimize the illness and death caused by malaria. Development of new drugs becomes ever more urgent as drug resistance emerges. Among promising compounds now being developed to treat malaria are several unrelated molecules that each inhibit the same protein in the malaria parasite-ATP4. Here, we exploited the genetic tractability of P. knowlesi to replace its own ATP4 genes with orthologues from five human-infective species to understand the drug susceptibility differences among these parasites. We previously estimated the susceptibility to ATP4-targeting drugs of each species using clinical samples from malaria patients. These estimates closely matched those of the corresponding "hybrid" P. knowlesi parasites carrying introduced ATP4 genes. Thus, species-specific ATP4 inhibitor efficacy is directly determined by the sequence of the gene. Our novel approach to understanding cross-species susceptibility/resistance can strongly support the effort to develop antimalarials that effectively target all human malaria parasite species.
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Affiliation(s)
- Franziska Mohring
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Donelly A. van Schalkwyk
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Ryan C. Henrici
- Center for Global Health, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA
| | | | - Didier Leroy
- Medicines for Malaria Venture, Geneva, Switzerland
| | - Colin J. Sutherland
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
- UK Health Security Agency Malaria Reference Laboratory, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Robert W. Moon
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
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6
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Hou MM, Barrett JR, Themistocleous Y, Rawlinson TA, Diouf A, Martinez FJ, Nielsen CM, Lias AM, King LDW, Edwards NJ, Greenwood NM, Kingham L, Poulton ID, Khozoee B, Goh C, Mac Lochlainn DJ, Salkeld J, Guilotte-Blisnick M, Huon C, Mohring F, Reimer JM, Chauhan VS, Mukherjee P, Biswas S, Taylor IJ, Lawrie AM, Cho JS, Nugent FL, Long CA, Moon RW, Miura K, Silk SE, Chitnis CE, Minassian AM, Draper SJ. Impact of a blood-stage vaccine on Plasmodium vivax malaria. medRxiv 2022:2022.05.27.22275375. [PMID: 35664997 PMCID: PMC9164524 DOI: 10.1101/2022.05.27.22275375] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Background There are no licensed vaccines against Plasmodium vivax , the most common cause of malaria outside of Africa. Methods We conducted two Phase I/IIa clinical trials to assess the safety, immunogenicity and efficacy of two vaccines targeting region II of P. vivax Duffy-binding protein (PvDBPII). Recombinant viral vaccines (using ChAd63 and MVA vectors) were administered at 0, 2 months or in a delayed dosing regimen (0, 17, 19 months), whilst a protein/adjuvant formulation (PvDBPII/Matrix-M™) was administered monthly (0, 1, 2 months) or in a delayed dosing regimen (0, 1, 14 months). Delayed regimens were due to trial halts during the COVID-19 pandemic. Volunteers underwent heterologous controlled human malaria infection (CHMI) with blood-stage P. vivax parasites at 2-4 weeks following their last vaccination, alongside unvaccinated controls. Efficacy was assessed by comparison of parasite multiplication rate (PMR) in blood post-CHMI, modelled from parasitemia measured by quantitative polymerase-chain-reaction (qPCR). Results Thirty-two volunteers were enrolled and vaccinated (n=16 for each vaccine). No safety concerns were identified. PvDBPII/Matrix-M™, given in the delayed dosing regimen, elicited the highest antibody responses and reduced the mean PMR following CHMI by 51% (range 36-66%; n=6) compared to unvaccinated controls (n=13). No other vaccine or regimen impacted parasite growth. In vivo growth inhibition of blood-stage P. vivax correlated with functional antibody readouts of vaccine immunogenicity. Conclusions Vaccination of malaria-naïve adults with a delayed booster regimen of PvDBPII/ Matrix-M™ significantly reduces the growth of blood-stage P. vivax . Funded by the European Commission and Wellcome Trust; VAC069, VAC071 and VAC079 ClinicalTrials.gov numbers NCT03797989 , NCT04009096 and NCT04201431 .
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Affiliation(s)
- Mimi M Hou
- Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, UK
- The Jenner Institute, University of Oxford, Oxford, OX3 7DQ, UK
| | - Jordan R Barrett
- Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, UK
- The Jenner Institute, University of Oxford, Oxford, OX3 7DQ, UK
| | | | | | - Ababacar Diouf
- Laboratory of Malaria and Vector Research, NIAID/NIH, Rockville, MD 20852, USA
| | - Francisco J Martinez
- Unité de Biologie de Plasmodium et Vaccins, Institut Pasteur, Université Paris Cité, 25-28 Rue du Dr Roux, 75015 Paris, France
| | - Carolyn M Nielsen
- Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, UK
- The Jenner Institute, University of Oxford, Oxford, OX3 7DQ, UK
| | - Amelia M Lias
- Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, UK
- The Jenner Institute, University of Oxford, Oxford, OX3 7DQ, UK
| | - Lloyd D W King
- Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, UK
- The Jenner Institute, University of Oxford, Oxford, OX3 7DQ, UK
| | - Nick J Edwards
- The Jenner Institute, University of Oxford, Oxford, OX3 7DQ, UK
| | | | - Lucy Kingham
- The Jenner Institute, University of Oxford, Oxford, OX3 7DQ, UK
| | - Ian D Poulton
- The Jenner Institute, University of Oxford, Oxford, OX3 7DQ, UK
| | - Baktash Khozoee
- The Jenner Institute, University of Oxford, Oxford, OX3 7DQ, UK
| | - Cyndi Goh
- The Jenner Institute, University of Oxford, Oxford, OX3 7DQ, UK
| | - Dylan J Mac Lochlainn
- Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, UK
- The Jenner Institute, University of Oxford, Oxford, OX3 7DQ, UK
| | - Jo Salkeld
- Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, UK
- The Jenner Institute, University of Oxford, Oxford, OX3 7DQ, UK
| | - Micheline Guilotte-Blisnick
- Unité de Biologie de Plasmodium et Vaccins, Institut Pasteur, Université Paris Cité, 25-28 Rue du Dr Roux, 75015 Paris, France
| | - Christèle Huon
- Unité de Biologie de Plasmodium et Vaccins, Institut Pasteur, Université Paris Cité, 25-28 Rue du Dr Roux, 75015 Paris, France
| | - Franziska Mohring
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK
| | | | - Virander S Chauhan
- International Centre for Genetic Engineering and Biotechnology (ICGEB), New Delhi, India
| | | | - Sumi Biswas
- The Jenner Institute, University of Oxford, Oxford, OX3 7DQ, UK
| | - Iona J Taylor
- The Jenner Institute, University of Oxford, Oxford, OX3 7DQ, UK
| | - Alison M Lawrie
- The Jenner Institute, University of Oxford, Oxford, OX3 7DQ, UK
| | - Jee-Sun Cho
- Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, UK
- The Jenner Institute, University of Oxford, Oxford, OX3 7DQ, UK
| | - Fay L Nugent
- The Jenner Institute, University of Oxford, Oxford, OX3 7DQ, UK
| | - Carole A Long
- Laboratory of Malaria and Vector Research, NIAID/NIH, Rockville, MD 20852, USA
| | - Robert W Moon
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK
| | - Kazutoyo Miura
- Laboratory of Malaria and Vector Research, NIAID/NIH, Rockville, MD 20852, USA
| | - Sarah E Silk
- Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, UK
- The Jenner Institute, University of Oxford, Oxford, OX3 7DQ, UK
| | - Chetan E Chitnis
- Unité de Biologie de Plasmodium et Vaccins, Institut Pasteur, Université Paris Cité, 25-28 Rue du Dr Roux, 75015 Paris, France
| | - Angela M Minassian
- Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, UK
- The Jenner Institute, University of Oxford, Oxford, OX3 7DQ, UK
| | - Simon J Draper
- Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, UK
- The Jenner Institute, University of Oxford, Oxford, OX3 7DQ, UK
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7
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Mohring F, Rawlinson TA, Draper SJ, Moon RW. Multiplication and Growth Inhibition Activity Assays for the Zoonotic Malaria Parasite, Plasmodium knowlesi. Bio Protoc 2020; 10:e3743. [PMID: 33659403 DOI: 10.21769/bioprotoc.3743] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 06/15/2020] [Accepted: 07/15/2020] [Indexed: 01/19/2023] Open
Abstract
Malaria remains a major cause of morbidity and mortality globally. Clinical symptoms of the disease arise from the growth and multiplication of Plasmodium parasites within the blood of the host. Thus in vitro assays to determine how drug, antibody and genetic perturbations affect the growth rate of Plasmodium parasites are essential for the development of new therapeutics and improving our understanding of parasite biology. As both P. falciparum and P. knowlesi can be maintained in culture with human red blood cells, the effect of antimalarial drugs and inhibitory antibodies that target the invasion capacity of Plasmodium parasites are routinely investigated by using multiplication assays or growth inhibition assays against these two species. This protocol gives detailed step-by-step procedures to carry out flow cytometry-based multiplication assays and growth inhibition activity assays to test neutralizing antibodies based on the activity of the parasite enzyme lactate dehydrogenase of Plasmodium knowlesi adapted to human red blood cell culture. Whilst similar assays are well established for P. falciparum, P. knowlesi is more closely related to all other human infective species ( Pacheco et al., 2018 ) and so can be used as a surrogate for testing drugs and vaccines for other malaria species such as P. vivax, which is the most widespread cause of malaria outside of Africa, but cannot yet be cultured under laboratory conditions.
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Affiliation(s)
- Franziska Mohring
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London WC1E 7HT, United Kingdom
| | - Thomas A Rawlinson
- The Jenner Institute, University of Oxford, Oxford, OX3 7DQ, United Kingdom
| | - Simon J Draper
- The Jenner Institute, University of Oxford, Oxford, OX3 7DQ, United Kingdom
| | - Robert W Moon
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London WC1E 7HT, United Kingdom
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Mohring F, Hart MN, Patel A, Baker DA, Moon RW. CRISPR-Cas9 Genome Editing of Plasmodium knowlesi. Bio Protoc 2020; 10:e3522. [PMID: 33654746 PMCID: PMC7842605 DOI: 10.21769/bioprotoc.3522] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 12/15/2019] [Accepted: 12/23/2019] [Indexed: 12/28/2022] Open
Abstract
Plasmodium knowlesi is a zoonotic malaria parasite in Southeast Asia that can cause severe and fatal malaria in humans. The main hosts are Macaques, but modern diagnostic tools reveal increasing numbers of human infections. After P. falciparum, P. knowlesi is the only other malaria parasite capable of being maintained in long term in vitro culture with human red blood cells (RBCs). Its closer ancestry to other non-falciparum human malaria parasites, more balanced AT-content, larger merozoites and higher transfection efficiencies, gives P. knowlesi some key advantages over P. falciparum for the study of malaria parasite cell/molecular biology. Here, we describe the generation of marker-free CRISPR gene-edited P. knowlesi parasites, the fast and scalable production of transfection constructs and analysis of transfection efficiencies. Our protocol allows rapid, reliable and unlimited rounds of genome editing in P. knowlesi requiring only a single recyclable selection marker.
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Affiliation(s)
- Franziska Mohring
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London WC1E 7HT, United Kingdom
| | - Melissa N. Hart
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London WC1E 7HT, United Kingdom
| | - Avnish Patel
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London WC1E 7HT, United Kingdom
| | - David A. Baker
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London WC1E 7HT, United Kingdom
| | - Robert W. Moon
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London WC1E 7HT, United Kingdom
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9
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Mohring F, Hart MN, Rawlinson TA, Henrici R, Charleston JA, Diez Benavente E, Patel A, Hall J, Almond N, Campino S, Clark TG, Sutherland CJ, Baker DA, Draper SJ, Moon RW. Rapid and iterative genome editing in the malaria parasite Plasmodium knowlesi provides new tools for P. vivax research. eLife 2019; 8:45829. [PMID: 31205002 PMCID: PMC6579517 DOI: 10.7554/elife.45829] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Accepted: 05/28/2019] [Indexed: 12/14/2022] Open
Abstract
Tackling relapsing Plasmodium vivax and zoonotic Plasmodium knowlesi infections is critical to reducing malaria incidence and mortality worldwide. Understanding the biology of these important and related parasites was previously constrained by the lack of robust molecular and genetic approaches. Here, we establish CRISPR-Cas9 genome editing in a culture-adapted P. knowlesi strain and define parameters for optimal homology-driven repair. We establish a scalable protocol for the production of repair templates by PCR and demonstrate the flexibility of the system by tagging proteins with distinct cellular localisations. Using iterative rounds of genome-editing we generate a transgenic line expressing P. vivax Duffy binding protein (PvDBP), a lead vaccine candidate. We demonstrate that PvDBP plays no role in reticulocyte restriction but can alter the macaque/human host cell tropism of P. knowlesi. Critically, antibodies raised against the P. vivax antigen potently inhibit proliferation of this strain, providing an invaluable tool to support vaccine development.
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Affiliation(s)
- Franziska Mohring
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Melissa Natalie Hart
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | | | - Ryan Henrici
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - James A Charleston
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Ernest Diez Benavente
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Avnish Patel
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Joanna Hall
- Division of Infectious Disease Diagnostics, National Institute for Biological Standards and Control, Health Protection Agency, Hertfordshire, United Kingdom
| | - Neil Almond
- Division of Infectious Disease Diagnostics, National Institute for Biological Standards and Control, Health Protection Agency, Hertfordshire, United Kingdom
| | - Susana Campino
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Taane G Clark
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Colin J Sutherland
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - David A Baker
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Simon J Draper
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Robert William Moon
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
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10
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Knuepfer E, Wright KE, Kumar Prajapati S, Rawlinson TA, Mohring F, Koch M, Lyth OR, Howell SA, Villasis E, Snijders AP, Moon RW, Draper SJ, Rosanas-Urgell A, Higgins MK, Baum J, Holder AA. Divergent roles for the RH5 complex components, CyRPA and RIPR in human-infective malaria parasites. PLoS Pathog 2019; 15:e1007809. [PMID: 31185066 PMCID: PMC6588255 DOI: 10.1371/journal.ppat.1007809] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2018] [Revised: 06/21/2019] [Accepted: 05/01/2019] [Indexed: 12/26/2022] Open
Abstract
Malaria is caused by Plasmodium parasites, which invade and replicate in erythrocytes. For Plasmodium falciparum, the major cause of severe malaria in humans, a heterotrimeric complex comprised of the secreted parasite proteins, PfCyRPA, PfRIPR and PfRH5 is essential for erythrocyte invasion, mediated by the interaction between PfRH5 and erythrocyte receptor basigin (BSG). However, whilst CyRPA and RIPR are present in most Plasmodium species, RH5 is found only in the small Laverania subgenus. Existence of a complex analogous to PfRH5-PfCyRPA-PfRIPR targeting BSG, and involvement of CyRPA and RIPR in invasion, however, has not been addressed in non-Laverania parasites. Here, we establish that unlike P. falciparum, P. knowlesi and P. vivax do not universally require BSG as a host cell invasion receptor. Although we show that both PkCyRPA and PkRIPR are essential for successful invasion of erythrocytes by P. knowlesi parasites in vitro, neither protein forms a complex with each other or with an RH5-like molecule. Instead, PkRIPR is part of a different trimeric protein complex whereas PkCyRPA appears to function without other parasite binding partners. It therefore appears that in the absence of RH5, outside of the Laverania subgenus, RIPR and CyRPA have different, independent functions crucial for parasite survival. Malaria is one of the most devastating infectious diseases, causing significant human suffering and death. It is caused by parasites of the genus Plasmodium proliferating in the bloodstream. Understanding the mechanism of erythrocyte invasion is key for developing novel intervention strategies. P. falciparum, the cause of the most severe form of malaria, requires the interaction of a trimeric protein complex RH5-CyRPA-RIPR with the host receptor BSG for successful invasion. We show here that the BSG receptor is not essential for invasion by two other major causes of human malaria, P. vivax and P. knowlesi. Furthermore, we analyzed the role of CyRPA and RIPR in the absence of an RH5-like molecule in P. knowlesi and show that these molecules do not associate to form a protein complex unlike in the presence of RH5 in P. falciparum. PkRIPR is part of a different protein complex. Despite this difference CyRPA and RIPR still have essential functions during host cell invasion in other important human malaria-causing parasites.
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Affiliation(s)
- Ellen Knuepfer
- Malaria Parasitology Laboratory, The Francis Crick Institute, London, United Kingdom
- * E-mail: (EK); (KEW); (JB); (AAH)
| | - Katherine E. Wright
- Department of Life Sciences, Imperial College London, London, United Kingdom
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
- * E-mail: (EK); (KEW); (JB); (AAH)
| | | | | | - Franziska Mohring
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Marion Koch
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Oliver R. Lyth
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Steven A. Howell
- Proteomics Science and Technology Platform, The Francis Crick Institute, London, United Kingdom
| | - Elizabeth Villasis
- Departamento de Ciencias Celulares y Moleculares, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Ambrosius P. Snijders
- Proteomics Science and Technology Platform, The Francis Crick Institute, London, United Kingdom
| | - Robert W. Moon
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Simon J. Draper
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Anna Rosanas-Urgell
- Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
| | - Matthew K. Higgins
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Jake Baum
- Department of Life Sciences, Imperial College London, London, United Kingdom
- * E-mail: (EK); (KEW); (JB); (AAH)
| | - Anthony A. Holder
- Malaria Parasitology Laboratory, The Francis Crick Institute, London, United Kingdom
- * E-mail: (EK); (KEW); (JB); (AAH)
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11
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Schuh AK, Rahbari M, Heimsch KC, Mohring F, Gabryszewski SJ, Weder S, Buchholz K, Rahlfs S, Fidock DA, Becker K. Stable Integration and Comparison of hGrx1-roGFP2 and sfroGFP2 Redox Probes in the Malaria Parasite Plasmodium falciparum. ACS Infect Dis 2018; 4:1601-1612. [PMID: 30129748 DOI: 10.1021/acsinfecdis.8b00140] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Studying redox metabolism in malaria parasites is of great interest for understanding parasite biology, parasite-host interactions, and mechanisms of drug action. Genetically encoded fluorescent redox sensors have recently been described as powerful tools for determining the glutathione-dependent redox potential in living parasites. In the present study, we genomically integrated and expressed the ratiometric redox sensors hGrx1-roGFP2 (human glutaredoxin 1 fused to reduction-oxidation sensitive green fluorescent protein) and sfroGFP2 (superfolder roGFP2) in the cytosol of NF54- attB blood-stage Plasmodium falciparum parasites. Both sensors were evaluated in vitro and in cell culture with regard to their fluorescence properties and reactivity. As genomic integration allows for the stable expression of redox sensors in parasites, we systematically compared single live-cell imaging with plate reader detection. For these comparisons, short-term effects of redox-active compounds were analyzed along with mid- and long-term effects of selected antimalarial agents. Of note, the single components of the redox probes themselves did not influence the redox balance of the parasites. Our analyses revealed comparable results for both the hGrx1-roGFP2 and sfroGFP2 probes, with sfroGFP2 exhibiting a more pronounced fluorescence intensity in cellulo. Accordingly, the sfroGFP2 probe was employed to monitor the fluorescence signals throughout the parasites' asexual life cycle. Through the use of stable genomic integration, we demonstrate a means of overcoming the limitations of transient transfection, allowing more detailed in-cell studies as well as high-throughput analyses using plate reader-based approaches.
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Affiliation(s)
- Anna Katharina Schuh
- Biochemistry and Molecular Biology, Interdisciplinary Research Center, Justus Liebig University Giessen, 35392 Giessen, Germany
| | - Mahsa Rahbari
- Biochemistry and Molecular Biology, Interdisciplinary Research Center, Justus Liebig University Giessen, 35392 Giessen, Germany
| | - Kim C. Heimsch
- Biochemistry and Molecular Biology, Interdisciplinary Research Center, Justus Liebig University Giessen, 35392 Giessen, Germany
| | - Franziska Mohring
- Biochemistry and Molecular Biology, Interdisciplinary Research Center, Justus Liebig University Giessen, 35392 Giessen, Germany
| | | | - Stine Weder
- Biochemistry and Molecular Biology, Interdisciplinary Research Center, Justus Liebig University Giessen, 35392 Giessen, Germany
| | - Kathrin Buchholz
- Biochemistry and Molecular Biology, Interdisciplinary Research Center, Justus Liebig University Giessen, 35392 Giessen, Germany
| | - Stefan Rahlfs
- Biochemistry and Molecular Biology, Interdisciplinary Research Center, Justus Liebig University Giessen, 35392 Giessen, Germany
| | | | - Katja Becker
- Biochemistry and Molecular Biology, Interdisciplinary Research Center, Justus Liebig University Giessen, 35392 Giessen, Germany
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12
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Lyth O, Vizcay-Barrena G, Wright KE, Haase S, Mohring F, Najer A, Henshall IG, Ashdown GW, Bannister LH, Drew DR, Beeson JG, Fleck RA, Moon RW, Wilson DW, Baum J. Cellular dissection of malaria parasite invasion of human erythrocytes using viable Plasmodium knowlesi merozoites. Sci Rep 2018; 8:10165. [PMID: 29976932 PMCID: PMC6033891 DOI: 10.1038/s41598-018-28457-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Accepted: 06/22/2018] [Indexed: 12/21/2022] Open
Abstract
Plasmodium knowlesi, a zoonotic parasite causing severe-to-lethal malaria disease in humans, has only recently been adapted to continuous culture with human red blood cells (RBCs). In comparison with the most virulent human malaria, Plasmodium falciparum, there are, however, few cellular tools available to study its biology, in particular direct investigation of RBC invasion by blood-stage P. knowlesi merozoites. This leaves our current understanding of biological differences across pathogenic Plasmodium spp. incomplete. Here, we report a robust method for isolating viable and invasive P. knowlesi merozoites to high purity and yield. Using this approach, we present detailed comparative dissection of merozoite invasion (using a variety of microscopy platforms) and direct assessment of kinetic differences between knowlesi and falciparum merozoites. We go on to assess the inhibitory potential of molecules targeting discrete steps of invasion in either species via a quantitative invasion inhibition assay, identifying a class of polysulfonate polymer able to efficiently inhibit invasion in both, providing a foundation for pan-Plasmodium merozoite inhibitor development. Given the close evolutionary relationship between P. knowlesi and P. vivax, the second leading cause of malaria-related morbidity, this study paves the way for inter-specific dissection of invasion by all three major pathogenic malaria species.
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Affiliation(s)
- Oliver Lyth
- Department of Life Sciences, Imperial College London, Sir Alexander Fleming Building, Exhibition Road, South Kensington, London, UK
| | - Gema Vizcay-Barrena
- Centre for Ultrastructural Imaging, Guy's Campus, King's College London, London, UK
| | - Katherine E Wright
- Department of Life Sciences, Imperial College London, Sir Alexander Fleming Building, Exhibition Road, South Kensington, London, UK
| | - Silvia Haase
- Department of Life Sciences, Imperial College London, Sir Alexander Fleming Building, Exhibition Road, South Kensington, London, UK
| | - Franziska Mohring
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London, UK
| | - Adrian Najer
- Department of Life Sciences, Imperial College London, Sir Alexander Fleming Building, Exhibition Road, South Kensington, London, UK
| | - Isabelle G Henshall
- Research Centre for Infectious Diseases, School of Biological Sciences, The University of Adelaide, Adelaide, Australia
| | - George W Ashdown
- Department of Life Sciences, Imperial College London, Sir Alexander Fleming Building, Exhibition Road, South Kensington, London, UK
| | - Lawrence H Bannister
- Centre for Ultrastructural Imaging, Guy's Campus, King's College London, London, UK
| | - Damien R Drew
- Burnet Institute, 85 Commercial Road, Melbourne, Victoria, Australia.,Central Clinical School, Monash University, Victoria, Australia
| | - James G Beeson
- Burnet Institute, 85 Commercial Road, Melbourne, Victoria, Australia.,Central Clinical School, Monash University, Victoria, Australia
| | - Roland A Fleck
- Centre for Ultrastructural Imaging, Guy's Campus, King's College London, London, UK
| | - Robert W Moon
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London, UK
| | - Danny W Wilson
- Research Centre for Infectious Diseases, School of Biological Sciences, The University of Adelaide, Adelaide, Australia. .,Burnet Institute, 85 Commercial Road, Melbourne, Victoria, Australia.
| | - Jake Baum
- Department of Life Sciences, Imperial College London, Sir Alexander Fleming Building, Exhibition Road, South Kensington, London, UK.
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13
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Fraschka SA, Filarsky M, Hoo R, Niederwieser I, Yam XY, Brancucci NMB, Mohring F, Mushunje AT, Huang X, Christensen PR, Nosten F, Bozdech Z, Russell B, Moon RW, Marti M, Preiser PR, Bártfai R, Voss TS. Comparative Heterochromatin Profiling Reveals Conserved and Unique Epigenome Signatures Linked to Adaptation and Development of Malaria Parasites. Cell Host Microbe 2018; 23:407-420.e8. [PMID: 29503181 PMCID: PMC5853956 DOI: 10.1016/j.chom.2018.01.008] [Citation(s) in RCA: 80] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Revised: 11/22/2017] [Accepted: 01/16/2018] [Indexed: 01/23/2023]
Abstract
Heterochromatin-dependent gene silencing is central to the adaptation and survival of Plasmodium falciparum malaria parasites, allowing clonally variant gene expression during blood infection in humans. By assessing genome-wide heterochromatin protein 1 (HP1) occupancy, we present a comprehensive analysis of heterochromatin landscapes across different Plasmodium species, strains, and life cycle stages. Common targets of epigenetic silencing include fast-evolving multi-gene families encoding surface antigens and a small set of conserved HP1-associated genes with regulatory potential. Many P. falciparum heterochromatic genes are marked in a strain-specific manner, increasing the parasite's adaptive capacity. Whereas heterochromatin is strictly maintained during mitotic proliferation of asexual blood stage parasites, substantial heterochromatin reorganization occurs in differentiating gametocytes and appears crucial for the activation of key gametocyte-specific genes and adaptation of erythrocyte remodeling machinery. Collectively, these findings provide a catalog of heterochromatic genes and reveal conserved and specialized features of epigenetic control across the genus Plasmodium.
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Affiliation(s)
- Sabine A Fraschka
- Department of Molecular Biology, Faculty of Science, Radboud University, 6525 GA Nijmegen, the Netherlands
| | - Michael Filarsky
- Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, 4051 Basel, Switzerland; University of Basel, 4001 Basel, Switzerland
| | - Regina Hoo
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Igor Niederwieser
- Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, 4051 Basel, Switzerland; University of Basel, 4001 Basel, Switzerland
| | - Xue Yan Yam
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Nicolas M B Brancucci
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow G12 8QQ, UK; Department of Immunology and Infectious Diseases, Harvard TH Chan School of Public Health, Boston, MA 02155, USA
| | - Franziska Mohring
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK
| | - Annals T Mushunje
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Ximei Huang
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Peter R Christensen
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot 63110, Thailand
| | - Francois Nosten
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot 63110, Thailand; Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine Research Building, University of Oxford Old Road Campus, Oxford OX3 7FZ, UK
| | - Zbynek Bozdech
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Bruce Russell
- Department of Microbiology and Immunology, University of Otago, Dunedin 9054, New Zealand
| | - Robert W Moon
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK
| | - Matthias Marti
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow G12 8QQ, UK; Department of Immunology and Infectious Diseases, Harvard TH Chan School of Public Health, Boston, MA 02155, USA
| | - Peter R Preiser
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Richárd Bártfai
- Department of Molecular Biology, Faculty of Science, Radboud University, 6525 GA Nijmegen, the Netherlands.
| | - Till S Voss
- Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, 4051 Basel, Switzerland; University of Basel, 4001 Basel, Switzerland.
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14
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Shah J, Poruri A, Mark O, Khadilka U, Mohring F, Moon RW, Ramasamy R. A dual colour fluorescence in situ hybridization (FISH) assay for identifying the zoonotic malaria parasite Plasmodium knowlesi with a potential application for the specific diagnosis of knowlesi malaria in peripheral-level laboratories of Southeast Asia. Parasit Vectors 2017; 10:342. [PMID: 28724402 PMCID: PMC5517825 DOI: 10.1186/s13071-017-2273-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Accepted: 07/05/2017] [Indexed: 01/28/2023] Open
Abstract
Background Plasmodium knowlesi is primarily responsible for zoonotic malaria in several Southeast Asian countries. Precise identification of the parasite in the blood of patients presently relies on an expensive and elaborate PCR procedure because microscopic examination of blood and other available field identification techniques lack adequate specificity. Therefore, the use of a simple and inexpensive dual-colour fluorescence in situ hybridization (FISH) assay, analogous to FISH assays recently described for Plasmodium falciparum and Plasmodium vivax, was investigated as a potential tool for identifying P. knowlesi. Results A P. knowlesi 18S rDNA sequence-based DNA probe was used to test thin blood smears of P. knowlesi by FISH, and fluorescence viewed in a light microscope fitted with a light emitting diode light source and appropriate emission and barrier filters. The limit of detection in the P. knowlesi FISH assay was 84 parasites per μl in infected monkey blood and 61 parasites per μl for P. knowlesi cultured in human blood. The P. knowlesi-specific FISH probe detected only P. knowlesi and not P. falciparum, Plasmodium malariae, Plasmodium ovale, P. vivax or a panel of other human blood-borne pathogens. A previously described Plasmodium genus-specific probe used simultaneously in the P. knowlesi FISH assay reacted with all tested Plasmodium species. Conclusions To our knowledge, this is the first description of a FISH assay for P. knowlesi that is potentially useful for diagnosing infections in remote laboratories in endemic countries. Electronic supplementary material The online version of this article (doi:10.1186/s13071-017-2273-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jyotsna Shah
- ID-FISH Technology, Palo Alto, CA, USA. .,IGeneX, Palo Alto, CA, USA.
| | - Akhila Poruri
- ID-FISH Technology, Palo Alto, CA, USA.,IGeneX, Palo Alto, CA, USA
| | - Olivia Mark
- ID-FISH Technology, Palo Alto, CA, USA.,IGeneX, Palo Alto, CA, USA
| | | | - Franziska Mohring
- London School of Hygiene and Tropical Medicine, Keppel Street, London, UK
| | - Robert W Moon
- London School of Hygiene and Tropical Medicine, Keppel Street, London, UK
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15
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Mohring F, Rahbari M, Zechmann B, Rahlfs S, Przyborski JM, Meyer AJ, Becker K. Determination of glutathione redox potential and pH value in subcellular compartments of malaria parasites. Free Radic Biol Med 2017; 104:104-117. [PMID: 28062360 DOI: 10.1016/j.freeradbiomed.2017.01.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Revised: 12/16/2016] [Accepted: 01/02/2017] [Indexed: 12/26/2022]
Abstract
The malaria parasite Plasmodium falciparum is exposed to multiple sources of oxidative challenge during its complex life cycle in the Anopheles vector and its human host. In order to further elucidate redox-based parasite host cell interactions and mechanisms of drug action, we targeted the genetically encoded glutathione redox sensor roGFP2 coupled to human glutaredoxin 1 (roGFP2-hGrx1) as well as the ratiometric pH sensor pHluorin to the apicoplast and the mitochondrion of P. falciparum. Using live cell imaging, this allowed for the first time the determination of the pH values of the apicoplast (7.12±0.40) and mitochondrion (7.37±0.09) in the intraerythrocytic asexual stages of the parasite. Based on the roGFP2-hGrx1 signals, glutathione-dependent redox potentials of -267mV and -328mV, respectively, were obtained. Employing these novel tools, initial studies on the effects of redox-active agents and clinically employed antimalarial drugs were carried out on both organelles.
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Affiliation(s)
- Franziska Mohring
- Biochemistry and Molecular Biology, Interdisciplinary Research Center, Justus Liebig University Giessen, Heinrich-Buff-Ring 26-32, 35392 Giessen, Germany
| | - Mahsa Rahbari
- Biochemistry and Molecular Biology, Interdisciplinary Research Center, Justus Liebig University Giessen, Heinrich-Buff-Ring 26-32, 35392 Giessen, Germany
| | - Bernd Zechmann
- Center for Microscopy and Imaging, Baylor University, 101 Bagby Ave., Waco, TX 76706, USA
| | - Stefan Rahlfs
- Biochemistry and Molecular Biology, Interdisciplinary Research Center, Justus Liebig University Giessen, Heinrich-Buff-Ring 26-32, 35392 Giessen, Germany
| | - Jude M Przyborski
- Parasitology, Philipps University Marburg, Karl-von-Frisch Strasse 8, 35043 Marburg, Germany
| | - Andreas J Meyer
- INRES-Chemical Signalling, University of Bonn, Friedrich-Ebert-Allee 144, 53113 Bonn, Germany
| | - Katja Becker
- Biochemistry and Molecular Biology, Interdisciplinary Research Center, Justus Liebig University Giessen, Heinrich-Buff-Ring 26-32, 35392 Giessen, Germany.
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Abstract
: The most important parasitic diseases, malaria, leishmaniasis, trypanosomiasis, and schistosomiasis, are a great burden to mankind, threatening the life of millions of people worldwide and mostly affecting the poorest. Because drug resistance is increasing and vaccines are rarely available, novel chemotherapeutic compounds are necessary in order to treat these devastating diseases. Insects serve as vectors of many human parasitic diseases and have been shown to express a huge variety of antimicrobial peptides (AMPs). Therefore, research activity on insect-derived AMPs has been increasing in the last 40 years. This chapter summarizes the current state of research on the possible role of AMPs as potential chemotherapeutic compounds against human parasitic diseases. As a representative antimicrobial peptide with antiparasitic activity, the structure of insect defensin A is shown [PDB accession code: 1ICA]. The molecule is surrounded by schematic representations of the human pathogenic parasites Plasmodium, Leishmania and Trypanosoma.
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Affiliation(s)
- Jette Pretzel
- Biochemistry and Molecular Biology, Interdisciplinary Research Center, Heinrich-Buff-Ring 26-32, 35392, Giessen, Germany
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Mohring F, Jortzik E, Becker K. Comparison of methods probing the intracellular redox milieu in Plasmodium falciparum. Mol Biochem Parasitol 2015; 206:75-83. [PMID: 26593282 DOI: 10.1016/j.molbiopara.2015.11.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Revised: 10/28/2015] [Accepted: 11/10/2015] [Indexed: 02/06/2023]
Abstract
Glutathione plays a crucial role in the redox regulation of the malaria parasite Plasmodium falciparum and is linked to drug resistance mechanisms, especially in resistance against the antimalarial drug chloroquine (CQ). The determination of the glutathione-dependent redox potential was recently established in living parasites using a cytosolically expressed biosensor comprising redox-sensitive green fluorescent protein coupled to human glutaredoxin 1 (hGrx1-roGFP2). In order to further elucidate redox changes induced by antimalarial drugs and to consolidate the application spectrum of the ratiometric biosensor we systematically compared it to other methods probing thiol and redox metabolism. Among these methods were cell disruptive and non-disruptive approaches including spectrophotometric assays with Ellman's reagent and naphthalene dicarboxyaldehyde as well as molecular probes such as ThiolTracker™ Violet and the dichlorofluorescein-based probe CM-H2DCFDA. To directly compare the methods, blood stages of the CQ-sensitive P. falciparum 3D7 strain were challenged with the oxidative agent diamide and the antimalarial drugs artemisinin and CQ for 1h, 4h, and 24h. For all conditions, dose-dependent changes in the different redox parameters could be monitored which are compared and discussed. We furthermore detected slight differences in thiol status of parasites transiently transfected with hGrx1-roGFP2 in comparison with control 3D7 cells. In conclusion, ThiolTracker™ Violet and, even more so, the hGrx1-roGFP2 probe reacted reliably and sensitively to drug induced changes in intracellular redox metabolism. These results were substantiated by classical cell disruptive methods.
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Affiliation(s)
- Franziska Mohring
- Biochemistry and Molecular Biology, Interdisciplinary Research Center, Justus Liebig University Giessen, 35392 Giessen, Germany
| | - Esther Jortzik
- Biochemistry and Molecular Biology, Interdisciplinary Research Center, Justus Liebig University Giessen, 35392 Giessen, Germany
| | - Katja Becker
- Biochemistry and Molecular Biology, Interdisciplinary Research Center, Justus Liebig University Giessen, 35392 Giessen, Germany.
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Bielitza M, Belorgey D, Ehrhardt K, Johann L, Lanfranchi DA, Gallo V, Schwarzer E, Mohring F, Jortzik E, Williams DL, Becker K, Arese P, Elhabiri M, Davioud-Charvet E. Antimalarial NADPH-Consuming Redox-Cyclers As Superior Glucose-6-Phosphate Dehydrogenase Deficiency Copycats. Antioxid Redox Signal 2015; 22:1337-51. [PMID: 25714942 PMCID: PMC4410756 DOI: 10.1089/ars.2014.6047] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Revised: 01/28/2015] [Accepted: 02/24/2015] [Indexed: 12/21/2022]
Abstract
AIMS Early phagocytosis of glucose-6-phosphate dehydrogenase (G6PD)-deficient erythrocytes parasitized by Plasmodium falciparum were shown to protect G6PD-deficient populations from severe malaria. Here, we investigated the mechanism of a novel antimalarial series, namely 3-[substituted-benzyl]-menadiones, to understand whether these NADPH-consuming redox-cyclers, which induce oxidative stress, mimic the natural protection of G6PD deficiency. RESULTS We demonstrated that the key benzoylmenadione metabolite of the lead compound acts as an efficient redox-cycler in NADPH-dependent methaemoglobin reduction, leading to the continuous formation of reactive oxygen species, ferrylhaemoglobin, and subsequent haemichrome precipitation. Structure-activity relationships evidenced that both drug metabolites and haemoglobin catabolites contribute to potentiate drug effects and inhibit parasite development. Disruption of redox homeostasis by the lead benzylmenadione was specifically induced in Plasmodium falciparum parasitized erythrocytes and not in non-infected cells, and was visualized via changes in the glutathione redox potential of living parasite cytosols. Furthermore, the redox-cycler shows additive and synergistic effects in combination with compounds affecting the NADPH flux in vivo. INNOVATION The lead benzylmenadione 1c is the first example of a novel redox-active agent that mimics the behavior of a falciparum parasite developing inside a G6PD-deficient red blood cell (RBC) giving rise to malaria protection, and it exerts specific additive effects that are inhibitory to parasite development, without harm for non-infected G6PD-sufficient or -deficient RBCs. CONCLUSION This strategy offers an innovative perspective for the development of future antimalarial drugs for G6PD-sufficient and -deficient populations.
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Affiliation(s)
- Max Bielitza
- UMR 7509 Centre National de la Recherche Scientifique and University of Strasbourg, European School of Chemistry, Polymers and Materials (ECPM), Strasbourg, France
| | - Didier Belorgey
- UMR 7509 Centre National de la Recherche Scientifique and University of Strasbourg, European School of Chemistry, Polymers and Materials (ECPM), Strasbourg, France
| | - Katharina Ehrhardt
- UMR 7509 Centre National de la Recherche Scientifique and University of Strasbourg, European School of Chemistry, Polymers and Materials (ECPM), Strasbourg, France
- Department of Infectiology, University of Heidelberg, Heidelberg, Germany
| | - Laure Johann
- UMR 7509 Centre National de la Recherche Scientifique and University of Strasbourg, European School of Chemistry, Polymers and Materials (ECPM), Strasbourg, France
| | - Don Antoine Lanfranchi
- UMR 7509 Centre National de la Recherche Scientifique and University of Strasbourg, European School of Chemistry, Polymers and Materials (ECPM), Strasbourg, France
| | - Valentina Gallo
- Department of Oncology, University of Torino Medical School, Torino, Italy
| | - Evelin Schwarzer
- Department of Oncology, University of Torino Medical School, Torino, Italy
| | - Franziska Mohring
- Biochemistry and Molecular Biology, Interdisciplinary Research Center (IFZ), Justus Liebig University of Giessen, Giessen, Germany
| | - Esther Jortzik
- Biochemistry and Molecular Biology, Interdisciplinary Research Center (IFZ), Justus Liebig University of Giessen, Giessen, Germany
| | - David L. Williams
- Department of Immunology/Microbiology, Rush University Medical Center, Chicago, Illinois
| | - Katja Becker
- Biochemistry and Molecular Biology, Interdisciplinary Research Center (IFZ), Justus Liebig University of Giessen, Giessen, Germany
| | - Paolo Arese
- Department of Oncology, University of Torino Medical School, Torino, Italy
| | - Mourad Elhabiri
- UMR 7509 Centre National de la Recherche Scientifique and University of Strasbourg, European School of Chemistry, Polymers and Materials (ECPM), Strasbourg, France
| | - Elisabeth Davioud-Charvet
- UMR 7509 Centre National de la Recherche Scientifique and University of Strasbourg, European School of Chemistry, Polymers and Materials (ECPM), Strasbourg, France
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Mohring F, Pretzel J, Jortzik E, Becker K. The Redox Systems of Plasmodium falciparum and Plasmodium vivax: Comparison, In silico Analyses and Inhibitor Studies. Curr Med Chem 2014; 21:1728-56. [DOI: 10.2174/0929867321666131201144612] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Revised: 06/17/2013] [Accepted: 10/17/2013] [Indexed: 11/22/2022]
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Kasozi D, Mohring F, Rahlfs S, Meyer AJ, Becker K. Real-time imaging of the intracellular glutathione redox potential in the malaria parasite Plasmodium falciparum. PLoS Pathog 2013; 9:e1003782. [PMID: 24348249 PMCID: PMC3857819 DOI: 10.1371/journal.ppat.1003782] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2013] [Accepted: 10/08/2013] [Indexed: 01/04/2023] Open
Abstract
In the malaria parasite Plasmodium falciparum, the cellular redox potential influences signaling events, antioxidant defense, and mechanisms of drug action and resistance. Until now, the real-time determination of the redox potential in malaria parasites has been limited because conventional approaches disrupt sub-cellular integrity. Using a glutathione biosensor comprising human glutaredoxin-1 linked to a redox-sensitive green fluorescent protein (hGrx1-roGFP2), we systematically characterized basal values and drug-induced changes in the cytosolic glutathione-dependent redox potential (EGSH) of drug-sensitive (3D7) and resistant (Dd2) P. falciparum parasites. Via confocal microscopy, we demonstrated that hGrx1-roGFP2 rapidly detects EGSH changes induced by oxidative and nitrosative stress. The cytosolic basal EGSH of 3D7 and Dd2 were estimated to be -314.2±3.1 mV and -313.9±3.4 mV, respectively, which is indicative of a highly reducing compartment. We furthermore monitored short-, medium-, and long-term changes in EGSH after incubation with various redox-active compounds and antimalarial drugs. Interestingly, the redox cyclers methylene blue and pyocyanin rapidly changed the fluorescence ratio of hGrx1-roGFP2 in the cytosol of P. falciparum, which can, however, partially be explained by a direct interaction with the probe. In contrast, quinoline and artemisinin-based antimalarial drugs showed strong effects on the parasites' EGSH after longer incubation times (24 h). As tested for various conditions, these effects were accompanied by a drop in total glutathione concentrations determined in parallel with alternative methods. Notably, the effects were generally more pronounced in the chloroquine-sensitive 3D7 strain than in the resistant Dd2 strain. Based on these results hGrx1-roGFP2 can be recommended as a reliable and specific biosensor for real-time spatiotemporal monitoring of the intracellular EGSH in P. falciparum. Applying this technique in further studies will enhance our understanding of redox regulation and mechanisms of drug action and resistance in Plasmodium and might also stimulate redox research in other pathogens.
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Affiliation(s)
- Denis Kasozi
- Biochemistry and Molecular Biology, Interdisciplinary Research Center, Justus Liebig University Giessen, Giessen, Germany
| | - Franziska Mohring
- Biochemistry and Molecular Biology, Interdisciplinary Research Center, Justus Liebig University Giessen, Giessen, Germany
| | - Stefan Rahlfs
- Biochemistry and Molecular Biology, Interdisciplinary Research Center, Justus Liebig University Giessen, Giessen, Germany
| | | | - Katja Becker
- Biochemistry and Molecular Biology, Interdisciplinary Research Center, Justus Liebig University Giessen, Giessen, Germany
- * E-mail:
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