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Platon L, Leroy D, Fidock DA, Ménard D. Drug-induced stress mediates Plasmodium falciparum ring-stage growth arrest and reduces in vitro parasite susceptibility to artemisinin. Microbiol Spectr 2024; 12:e0350023. [PMID: 38363132 PMCID: PMC10986542 DOI: 10.1128/spectrum.03500-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Accepted: 01/15/2024] [Indexed: 02/17/2024] Open
Abstract
During blood-stage infection, Plasmodium falciparum parasites are constantly exposed to a range of extracellular stimuli, including host molecules and drugs such as artemisinin derivatives, the mainstay of artemisinin-based combination therapies currently used as first-line treatment worldwide. Partial resistance of P. falciparum to artemisinin has been associated with mutations in the propeller domain of the Pfkelch13 gene, resulting in a fraction of ring stages that are able to survive exposure to artemisinin through a temporary growth arrest. Here, we investigated whether the growth arrest in ring-stage parasites reflects a general response to stress. We mimicked a stressful environment in vitro by exposing parasites to chloroquine or dihydroartemisinin (DHA). We observed that early ring-stage parasites pre-exposed to a stressed culture supernatant exhibited a temporary growth arrest and a reduced susceptibility to DHA, as assessed by the ring-stage survival assay, irrespective of their Pfkelch13 genotype. These data suggest that temporary growth arrest of early ring stages may be a constitutive, Pfkelch13-independent survival mechanism in P. falciparum.IMPORTANCEPlasmodium falciparum ring stages have the ability to sense the extracellular environment, regulate their growth, and enter a temporary growth arrest state in response to adverse conditions such as drug exposure. This temporary growth arrest results in reduced susceptibility to artemisinin in vitro. The signal responsible for this process is thought to be small molecules (less than 3 kDa) released by stressed mature-stage parasites. These data suggest that Pfkelch13-dependent artemisinin resistance and the growth arrest phenotype are two complementary but unrelated mechanisms of ring-stage survival in P. falciparum. This finding provides new insights into the field of P. falciparum antimalarial drug resistance by highlighting the extracellular compartment and cellular communication as an understudied mechanism.
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Affiliation(s)
- Lucien Platon
- Malaria Genetics and Resistance Unit, INSERM U1201, Institut Pasteur, Université Paris Cité, Paris, France
- Sorbonne Université, Collège Doctoral ED 515 Complexité du Vivant, Paris, France
- Malaria Parasite Biology and Vaccines Unit, Institut Pasteur, Université Paris Cité, Paris, France
- Institute of Parasitology and Tropical Diseases, UR7292 Dynamics of Host–Pathogen Interactions, Université de Strasbourg, Strasbourg, France
| | - Didier Leroy
- Department of Drug Discovery, Medicines for Malaria Venture, Geneva, Switzerland
| | - David A. Fidock
- Department of Microbiology and Immunology, Columbia University Irving Medical Center, New York, New York, USA
- Center for Malaria Therapeutics and Antimicrobial Resistance, Division of Infectious Diseases, Department of Medicine, Columbia University Irving Medical Center, New York, New York, USA
| | - Didier Ménard
- Malaria Genetics and Resistance Unit, INSERM U1201, Institut Pasteur, Université Paris Cité, Paris, France
- Malaria Parasite Biology and Vaccines Unit, Institut Pasteur, Université Paris Cité, Paris, France
- Institute of Parasitology and Tropical Diseases, UR7292 Dynamics of Host–Pathogen Interactions, Université de Strasbourg, Strasbourg, France
- Laboratory of Parasitology and Medical Mycology, CHU Strasbourg, Strasbourg, France
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Scheiner M, Burda PC, Ingmundson A. Moving on: How malaria parasites exit the liver. Mol Microbiol 2024; 121:328-340. [PMID: 37602900 DOI: 10.1111/mmi.15141] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Revised: 08/03/2023] [Accepted: 08/04/2023] [Indexed: 08/22/2023]
Abstract
An essential step in the life cycle of malaria parasites is their egress from hepatocytes, which enables the transition from the asymptomatic liver stage to the pathogenic blood stage of infection. To exit the liver, Plasmodium parasites first disrupt the parasitophorous vacuole membrane that surrounds them during their intracellular replication. Subsequently, parasite-filled structures called merosomes emerge from the infected cell. Shrouded by host plasma membrane, like in a Trojan horse, parasites enter the vasculature undetected by the host immune system and travel to the lung where merosomes rupture, parasites are released, and the blood infection stage begins. This complex, multi-step process must be carefully orchestrated by the parasite and requires extensive manipulation of the infected host cell. This review aims to outline the known signaling pathways that trigger exit, highlight Plasmodium proteins that contribute to the release of liver-stage merozoites, and summarize the accompanying changes to the hepatic host cell.
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Affiliation(s)
- Mattea Scheiner
- Molecular Parasitology, Humboldt University Berlin, Berlin, Germany
| | - Paul-Christian Burda
- Centre for Structural Systems Biology, Hamburg, Germany
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
- University of Hamburg, Hamburg, Germany
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Anaguano D, Adewale-Fasoro O, Vick GS, Yanik S, Blauwkamp J, Fierro MA, Absalon S, Srinivasan P, Muralidharan V. Plasmodium RON11 triggers biogenesis of the merozoite rhoptry pair and is essential for erythrocyte invasion. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.29.577654. [PMID: 38352500 PMCID: PMC10862748 DOI: 10.1101/2024.01.29.577654] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/22/2024]
Abstract
Malaria is a global and deadly human disease caused by the apicomplexan parasites of the genus Plasmodium. Parasite proliferation within human red blood cells (RBC) is associated with the clinical manifestations of the disease. This asexual expansion within human RBCs, begins with the invasion of RBCs by P. falciparum, which is mediated by the secretion of effectors from two specialized club-shaped secretory organelles in merozoite-stage parasites known as rhoptries. We investigated the function of the Rhoptry Neck Protein 11 (RON11), which contains seven transmembrane domains and calcium-binding EF-hand domains. We generated conditional mutants of the P. falciparum RON11. Knockdown of RON11 inhibits parasite growth by preventing merozoite invasion. The loss of RON11 did not lead to any defects in processing of rhoptry proteins but instead led to a decrease in the amount of rhoptry proteins. We utilized ultrastructure expansion microscopy (U-ExM) to determine the effect of RON11 knockdown on rhoptry biogenesis. Surprisingly, in the absence of RON11, fully developed merozoites had only one rhoptry each. The single rhoptry in RON11 deficient merozoites were morphologically typical with a bulb and a neck oriented into the apical polar ring. Moreover, rhoptry proteins are trafficked accurately to the single rhoptry in RON11 deficient parasites. These data show that in the absence of RON11, the first rhoptry is generated during schizogony but upon the start of cytokinesis, the second rhoptry never forms. Interestingly, these single-rhoptry merozoites were able to attach to host RBCs but are unable to invade RBCs. Instead, RON11 deficient merozoites continue to engage with RBC for prolonged periods eventually resulting in echinocytosis, a result of secreting the contents from the single rhoptry into the RBC. Together, our data show that RON11 triggers the de novo biogenesis of the second rhoptry and functions in RBC invasion.
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Affiliation(s)
- David Anaguano
- Department of Cellular Biology, University of Georgia, Athens, GA
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA
| | - Opeoluwa Adewale-Fasoro
- Department of Molecular Microbiology and Immunology, and Johns Hopkins Malaria Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD
- The Johns Hopkins Malaria Research Institute, Baltimore, MD, 21205, USA
| | - Grace S. Vick
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA
| | - Sean Yanik
- Department of Molecular Microbiology and Immunology, and Johns Hopkins Malaria Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD
- The Johns Hopkins Malaria Research Institute, Baltimore, MD, 21205, USA
| | - James Blauwkamp
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis IN
| | - Manuel A. Fierro
- Department of Cellular Biology, University of Georgia, Athens, GA
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA
| | - Sabrina Absalon
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis IN
| | - Prakash Srinivasan
- Department of Molecular Microbiology and Immunology, and Johns Hopkins Malaria Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD
- The Johns Hopkins Malaria Research Institute, Baltimore, MD, 21205, USA
| | - Vasant Muralidharan
- Department of Cellular Biology, University of Georgia, Athens, GA
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA
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Fréville A, Ressurreição M, van Ooij C. Identification of a non-exported Plasmepsin V substrate that functions in the parasitophorous vacuole of malaria parasites. mBio 2024; 15:e0122323. [PMID: 38078758 PMCID: PMC10790765 DOI: 10.1128/mbio.01223-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Accepted: 10/26/2023] [Indexed: 01/17/2024] Open
Abstract
IMPORTANCE In the manuscript, the authors investigate the role of the protease Plasmepsin V in the parasite-host interaction. Whereas processing by Plasmepsin V was previously thought to target a protein for export into the host cell, the authors now show that there are proteins cleaved by this protease that are not exported but instead function at the host-parasite interface. This changes the view of this protease, which turns out to have a much broader role than anticipated. The result shows that the protease may have a function much more similar to that of related organisms. The authors also investigate the requirements for protein export by analyzing exported and non-exported proteins and find commonalities between the proteins of each set that further our understanding of the requirements for protein export.
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Affiliation(s)
- Aline Fréville
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Margarida Ressurreição
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Christiaan van Ooij
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, United Kingdom
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Rawat RS, Gupta A, Antil N, Bhatnagar S, Singh M, Rawat A, Prasad TSK, Sharma P. Protein kinase PfPK2 mediated signalling is critical for host erythrocyte invasion by malaria parasite. PLoS Pathog 2023; 19:e1011770. [PMID: 37988347 PMCID: PMC10662742 DOI: 10.1371/journal.ppat.1011770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Accepted: 10/23/2023] [Indexed: 11/23/2023] Open
Abstract
Signalling pathways in malaria parasite remain poorly defined and major reason for this is the lack of understanding of the function of majority of parasite protein kinases and phosphatases in parasite signalling and its biology. In the present study, we have elucidated the function of Protein Kinase 2 (PfPK2), which is known to be indispensable for the survival of human malaria parasite Plasmodium falciparum. We demonstrate that it is involved in the invasion of host erythrocytes, which is critical for establishing infection. In addition, PfPK2 may also be involved in the maturation of the parasite post-invasion. PfPK2 regulates the release of microneme proteins like Apical Membrane Antigen 1 (AMA1), which facilitates the formation of Tight Junction between the merozoite and host erythrocyte- a key step in the process of invasion. Comparative phosphoproteomics studies revealed that PfPK2 may be involved in regulation of several key proteins involved in invasion and signalling. Furthermore, PfPK2 regulates the generation of cGMP and the release of calcium in the parasite, which are key second messengers for the process of invasion. These and other studies have shed light on a novel signalling pathway in which PfPK2 acts as an upstream regulator of important cGMP-calcium signalling, which plays an important role in parasite invasion.
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Affiliation(s)
- Rahul Singh Rawat
- Eukaryotic Gene Expression Laboratory, National Institute of Immunology, New Delhi, India
| | - Ankit Gupta
- Eukaryotic Gene Expression Laboratory, National Institute of Immunology, New Delhi, India
| | - Neelam Antil
- Institute of Bioinformatics, International Tech Park, Bangalore, India
- Amrita School of Biotechnology, Amrita Vishwa Vidyapeetham, Kollam, India
- Center for Systems Biology and Molecular Medicine, Yenepoya Research Centre, Yenepoya (Deemed to be University), Mangalore, India
| | - Sonika Bhatnagar
- Eukaryotic Gene Expression Laboratory, National Institute of Immunology, New Delhi, India
| | - Monika Singh
- Eukaryotic Gene Expression Laboratory, National Institute of Immunology, New Delhi, India
| | - Akanksha Rawat
- Eukaryotic Gene Expression Laboratory, National Institute of Immunology, New Delhi, India
| | - T. S. Keshava Prasad
- Center for Systems Biology and Molecular Medicine, Yenepoya Research Centre, Yenepoya (Deemed to be University), Mangalore, India
| | - Pushkar Sharma
- Eukaryotic Gene Expression Laboratory, National Institute of Immunology, New Delhi, India
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Pietsch E, Ramaprasad A, Bielfeld S, Wohlfarter Y, Maco B, Niedermüller K, Wilcke L, Kloehn J, Keller MA, Soldati-Favre D, Blackman MJ, Gilberger TW, Burda PC. A patatin-like phospholipase is important for mitochondrial function in malaria parasites. mBio 2023; 14:e0171823. [PMID: 37882543 PMCID: PMC10746288 DOI: 10.1128/mbio.01718-23] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Accepted: 09/12/2023] [Indexed: 10/27/2023] Open
Abstract
Plasmodium parasites rely on a functional electron transport chain (ETC) within their mitochondrion for proliferation, and compounds targeting mitochondrial functions are validated antimalarials. Here, we localize Plasmodium falciparum patatin-like phospholipase 2 (PfPNPLA2, PF3D7_1358000) to the mitochondrion and reveal that disruption of the PfPNPLA2 gene impairs asexual replication. PfPNPLA2-null parasites are hypersensitive to proguanil and inhibitors of the mitochondrial ETC, including atovaquone. In addition, PfPNPLA2-deficient parasites show reduced mitochondrial respiration and reduced mitochondrial membrane potential, indicating that disruption of PfPNPLA2 leads to a defect in the parasite ETC. Lipidomic analysis of the mitochondrial phospholipid cardiolipin (CL) reveals that loss of PfPNPLA2 is associated with a moderate shift toward shorter-chained and more saturated CL species, implying a contribution of PfPNPLA2 to CL remodeling. PfPNPLA2-deficient parasites display profound defects in gametocytogenesis, underlining the importance of a functional mitochondrial ETC during both the asexual and sexual development of the parasite. IMPORTANCE For their proliferation within red blood cells, malaria parasites depend on a functional electron transport chain (ETC) within their mitochondrion, which is the target of several antimalarial drugs. Here, we have used gene disruption to identify a patatin-like phospholipase, PfPNPLA2, as important for parasite replication and mitochondrial function in Plasmodium falciparum. Parasites lacking PfPNPLA2 show defects in their ETC and become hypersensitive to mitochondrion-targeting drugs. Furthermore, PfPNPLA2-deficient parasites show differences in the composition of their cardiolipins, a unique class of phospholipids with key roles in mitochondrial functions. Finally, we demonstrate that parasites devoid of PfPNPLA2 have a defect in gametocyte maturation, underlining the importance of a functional ETC for parasite transmission to the mosquito vector.
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Affiliation(s)
- Emma Pietsch
- Centre for Structural Systems Biology, Hamburg, Germany
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
- University of Hamburg, Hamburg, Germany
| | - Abhinay Ramaprasad
- Malaria Biochemistry Laboratory, The Francis Crick Institute, London, United Kingdom
| | - Sabrina Bielfeld
- Centre for Structural Systems Biology, Hamburg, Germany
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
- University of Hamburg, Hamburg, Germany
| | - Yvonne Wohlfarter
- Institute of Human Genetics, Medical University of Innsbruck, Innsbruck, Austria
| | - Bohumil Maco
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Korbinian Niedermüller
- Centre for Structural Systems Biology, Hamburg, Germany
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
- University of Hamburg, Hamburg, Germany
| | - Louisa Wilcke
- Centre for Structural Systems Biology, Hamburg, Germany
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
- University of Hamburg, Hamburg, Germany
| | - Joachim Kloehn
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Markus A. Keller
- Institute of Human Genetics, Medical University of Innsbruck, Innsbruck, Austria
| | - Dominique Soldati-Favre
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Michael J. Blackman
- Malaria Biochemistry Laboratory, The Francis Crick Institute, London, United Kingdom
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Tim-Wolf Gilberger
- Centre for Structural Systems Biology, Hamburg, Germany
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
- University of Hamburg, Hamburg, Germany
| | - Paul-Christian Burda
- Centre for Structural Systems Biology, Hamburg, Germany
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
- University of Hamburg, Hamburg, Germany
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7
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Vallintine T, van Ooij C. Distribution of malaria parasite-derived phosphatidylcholine in the infected erythrocyte. mSphere 2023; 8:e0013123. [PMID: 37606582 PMCID: PMC10597409 DOI: 10.1128/msphere.00131-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Accepted: 07/05/2023] [Indexed: 08/23/2023] Open
Abstract
Malaria parasites modify their host erythrocyte in multiple ways, leading to changes in the deformability, adhesiveness, and permeability of the host erythrocyte. Most of these changes are mediated by proteins exported from the parasite to the host erythrocyte, where these proteins interact with the host cell cytoskeleton or form complexes in the plasma membrane of the infected erythrocyte. In addition, malaria parasites induce the formation of membranous compartments-the parasitophorous vacuole, the tubovesicular network (TVN), the Maurer's clefts and small vesicles-within the infected erythrocyte, a cell that is normally devoid of internal membranes. After infection, changes also occur in the composition and asymmetry of the erythrocyte plasma membrane. Although many aspects of the mechanism of export of parasite proteins have become clear, the mechanism by which these membranous compartments are formed and expanded is almost entirely unknown. To determine whether parasite-derived phospholipids play a part in these processes, we applied a metabolic labeling technique that allows phosphatidylcholine to be labeled with a fluorophore. As the host erythrocyte cannot synthesize phospholipids, within infected erythrocytes, only parasite-derived phosphatidylcholine will be labeled with this technique. The results revealed that phosphatidylcholine produced by the parasite is distributed throughout the infected erythrocyte, including the TVN and the erythrocyte plasma membrane, but not Maurer's clefts. Interestingly, labeled phospholipids were also detected in the erythrocyte plasma membrane very soon after invasion of the parasites, indicating that the parasite may add phospholipids to the host erythrocyte during invasion. IMPORTANCE Here, we describe a previously unappreciated way in which the malaria parasite interacts with the host erythrocyte, namely, by the transfer of parasite phospholipids to the erythrocyte plasma membrane. This likely has important consequences for the survival of the parasite in the host cell and the host organism. We show that parasite-derived phospholipids are transferred from the parasite to the host erythrocyte plasma membrane and that other internal membranes that are produced after the parasite has invaded the cell are produced, at least in part, using parasite-derived phospholipids. The one exception to this is the Maurer's cleft, a membranous organelle that is involved in the transport of parasite proteins to the surface of the erythrocyte. This reveals that the Maurer's cleft is produced in a different manner than the other parasite-induced membranes. Overall, these findings provide a platform for the study of a new aspect of the host-parasite interaction.
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Affiliation(s)
- Tansy Vallintine
- Department of Infection Biology, Faculty of Infectious Disease, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Christiaan van Ooij
- Department of Infection Biology, Faculty of Infectious Disease, London School of Hygiene & Tropical Medicine, London, United Kingdom
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8
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Anaguano D, Dedkhad W, Brooks CF, Cobb DW, Muralidharan V. Time-resolved proximity biotinylation implicates a porin protein in export of transmembrane malaria parasite effectors. J Cell Sci 2023; 136:jcs260506. [PMID: 37772444 PMCID: PMC10651097 DOI: 10.1242/jcs.260506] [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: 08/18/2022] [Accepted: 09/21/2023] [Indexed: 09/30/2023] Open
Abstract
The malaria-causing parasite, Plasmodium falciparum completely remodels its host red blood cell (RBC) through the export of several hundred parasite proteins, including transmembrane proteins, across multiple membranes to the RBC. However, the process by which these exported membrane proteins are extracted from the parasite plasma membrane for export remains unknown. To address this question, we fused the exported membrane protein, skeleton binding protein 1 (SBP1), with TurboID, a rapid, efficient and promiscuous biotin ligase (SBP1TbID). Using time-resolved proximity biotinylation and label-free quantitative proteomics, we identified two groups of SBP1TbID interactors - early interactors (pre-export) and late interactors (post-export). Notably, two promising membrane-associated proteins were identified as pre-export interactors, one of which possesses a predicted translocon domain, that could facilitate the export of membrane proteins. Further investigation using conditional mutants of these candidate proteins showed that these proteins were essential for asexual growth and localize to the host-parasite interface during early stages of the intraerythrocytic cycle. These data suggest that they might play a role in ushering membrane proteins from the parasite plasma membrane for export to the host RBC.
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Affiliation(s)
- David Anaguano
- Department of Cellular Biology, University of Georgia, Athens, GA, USA
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA 30602, USA
| | - Watcharatip Dedkhad
- Department of Cellular Biology, University of Georgia, Athens, GA, USA
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA 30602, USA
| | - Carrie F Brooks
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA 30602, USA
| | - David W Cobb
- Department of Cellular Biology, University of Georgia, Athens, GA, USA
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA 30602, USA
| | - Vasant Muralidharan
- Department of Cellular Biology, University of Georgia, Athens, GA, USA
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA 30602, USA
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9
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Dash R, Skillman KM, Pereira L, Mascarenhas A, Dass S, Walke J, Almeida A, Fernandes M, Gomes E, White J, Chery-Karschney L, Khandeparkar A, Rathod PK, Duraisingh MT, Kanjee U. Development of a Plasmodium vivax biobank for functional ex vivo assays. Malar J 2023; 22:250. [PMID: 37653486 PMCID: PMC10470152 DOI: 10.1186/s12936-023-04668-2] [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: 03/17/2023] [Accepted: 08/07/2023] [Indexed: 09/02/2023] Open
Abstract
BACKGROUND Plasmodium vivax is the second most prevalent cause of malaria yet remains challenging to study due to the lack of a continuous in vitro culture system, highlighting the need to establish a biobank of clinical isolates with multiple freezes per sample for use in functional assays. Different methods for cryopreserving parasite isolates were compared and subsequently the most promising one was validated. Enrichment of early- and late-stage parasites and parasite maturation were quantified to facilitate assay planning. METHODS In order to compare cryopreservation protocols, nine clinical P. vivax isolates were frozen with four glycerolyte-based mixtures. Parasite recovery post thaw, post KCl-Percoll enrichment and in short-term in vitro culture was measured via slide microscopy. Enrichment of late-stage parasites by magnetic activated cell sorting (MACS) was measured. Short and long-term storage of parasites at either - 80 °C or liquid nitrogen were also compared. RESULTS Of the four cryopreservation mixtures, one mixture (glycerolyte:serum:RBC at a 2.5:1.5:1 ratio) resulted in improved parasite recovery and statistically significant (P < 0.05) enhancement in parasite survival in short-term in vitro culture. A parasite biobank was subsequently generated using this protocol resulting in a collection of 106 clinical isolates, each with 8 vials. The quality of the biobank was validated by measuring several factors from 47 thaws: the average reduction in parasitaemia post-thaw (25.3%); the average fold enrichment post KCl-Percoll (6.65-fold); and the average percent recovery of parasites (22.0%, measured from 30 isolates). During short-term in vitro culture, robust maturation of ring stage parasites to later stages (> 20% trophozoites, schizonts and gametocytes) was observed in 60.0% of isolates by 48 h. Enrichment of mature parasite stages via MACS showed good reproducibility, with an average of 30.0% post-MACS parasitaemia and an average of 5.30 × 105 parasites/vial. Finally, the effect of storage temperature was tested, and no large impacts from short-term (7 days) or long-term (7-10 years) storage at - 80 °C on parasite recovery, enrichment or viability was observed. CONCLUSIONS Here, an optimized freezing method for P. vivax clinical isolates is demonstrated as a template for the generation and validation of a parasite biobank for use in functional assays.
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Affiliation(s)
- Rashmi Dash
- Goa Medical College and Hospital, Bambolim, Goa, 403202, India
- Departments of Chemistry and Global Health, University of Washington, Seattle, WA, 98195, USA
| | - Kristen M Skillman
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, MA, 02115, USA
| | - Ligia Pereira
- Goa Medical College and Hospital, Bambolim, Goa, 403202, India
- Departments of Chemistry and Global Health, University of Washington, Seattle, WA, 98195, USA
| | - Anjali Mascarenhas
- Goa Medical College and Hospital, Bambolim, Goa, 403202, India
- Departments of Chemistry and Global Health, University of Washington, Seattle, WA, 98195, USA
| | - Sheena Dass
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, MA, 02115, USA
| | - Jayashri Walke
- Goa Medical College and Hospital, Bambolim, Goa, 403202, India
- Departments of Chemistry and Global Health, University of Washington, Seattle, WA, 98195, USA
| | - Anvily Almeida
- Goa Medical College and Hospital, Bambolim, Goa, 403202, India
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, MA, 02115, USA
| | - Mezia Fernandes
- Goa Medical College and Hospital, Bambolim, Goa, 403202, India
- Departments of Chemistry and Global Health, University of Washington, Seattle, WA, 98195, USA
| | - Edwin Gomes
- Goa Medical College and Hospital, Bambolim, Goa, 403202, India
| | - John White
- Departments of Chemistry and Global Health, University of Washington, Seattle, WA, 98195, USA
| | - Laura Chery-Karschney
- Departments of Chemistry and Global Health, University of Washington, Seattle, WA, 98195, USA
| | | | - Pradipsinh K Rathod
- Departments of Chemistry and Global Health, University of Washington, Seattle, WA, 98195, USA
| | - Manoj T Duraisingh
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, MA, 02115, USA
| | - Usheer Kanjee
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, MA, 02115, USA.
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10
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Vallintine T, van Ooij C. Timing of dense granule biogenesis in asexual malaria parasites. MICROBIOLOGY (READING, ENGLAND) 2023; 169:001389. [PMID: 37647112 PMCID: PMC10482371 DOI: 10.1099/mic.0.001389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 08/15/2023] [Indexed: 09/01/2023]
Abstract
Malaria is an important infectious disease that continues to claim hundreds of thousands of lives annually. The disease is caused by infection of host erythrocytes by apicomplexan parasites of the genus Plasmodium. The parasite contains three different apical organelles - micronemes, rhoptries and dense granules (DGs) - whose contents are secreted to mediate binding to and invasion of the host cell and the extensive remodelling of the host cell that occurs following invasion. Whereas the roles of micronemes and rhoptries in binding and invasion of the host erythrocyte have been studied in detail, the roles of DGs in Plasmodium parasites are poorly understood. They have been proposed to control host cell remodelling through regulated protein secretion after invasion, but many basic aspects of the biology of DGs remain unknown. Here we describe DG biogenesis timing for the first time, using RESA localization as a proxy for the timing of DG formation. We show that DG formation commences approximately 37 min prior to schizont egress, as measured by the recruitment of the DG marker RESA. Furthermore, using a bioinformatics approach, we aimed to predict additional cargo of the DGs and identified the J-dot protein HSP40 as a DG protein, further supporting the very early role of these organelles in the interaction of the parasite with the host cell.
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Affiliation(s)
- Tansy Vallintine
- Faculty of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | - Christiaan van Ooij
- Faculty of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, UK
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Jonsdottir TK, Elsworth B, Cobbold S, Gabriela M, Ploeger E, Parkyn Schneider M, Charnaud SC, Dans MG, McConville M, Bullen HE, Crabb BS, Gilson PR. PTEX helps efficiently traffic haemoglobinases to the food vacuole in Plasmodium falciparum. PLoS Pathog 2023; 19:e1011006. [PMID: 37523385 PMCID: PMC10414648 DOI: 10.1371/journal.ppat.1011006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 08/10/2023] [Accepted: 07/16/2023] [Indexed: 08/02/2023] Open
Abstract
A key element of Plasmodium biology and pathogenesis is the trafficking of ~10% of the parasite proteome into the host red blood cell (RBC) it infects. To cross the parasite-encasing parasitophorous vacuole membrane, exported proteins utilise a channel-forming protein complex termed the Plasmodium translocon of exported proteins (PTEX). PTEX is obligatory for parasite survival, both in vitro and in vivo, suggesting that at least some exported proteins have essential metabolic functions. However, to date only one essential PTEX-dependent process, the new permeability pathways, has been described. To identify other essential PTEX-dependant proteins/processes, we conditionally knocked down the expression of one of its core components, PTEX150, and examined which pathways were affected. Surprisingly, the food vacuole mediated process of haemoglobin (Hb) digestion was substantially perturbed by PTEX150 knockdown. Using a range of transgenic parasite lines and approaches, we show that two major Hb proteases; falcipain 2a and plasmepsin II, interact with PTEX core components, implicating the translocon in the trafficking of Hb proteases. We propose a model where these proteases are translocated into the PV via PTEX in order to reach the cytostome, located at the parasite periphery, prior to food vacuole entry. This work offers a second mechanistic explanation for why PTEX function is essential for growth of the parasite within its host RBC.
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Affiliation(s)
- Thorey K. Jonsdottir
- Malaria Virulence and Drug Discovery Group, Burnet Institute, Melbourne, Australia
- Department of Immunology and Microbiology, University of Melbourne, Melbourne, Australia
| | - Brendan Elsworth
- Malaria Virulence and Drug Discovery Group, Burnet Institute, Melbourne, Australia
| | - Simon Cobbold
- Department of Biochemistry and Molecular Biology, Bio21 Institute of Molecular Science and Biotechnology, University of Melbourne, Melbourne, Australia
| | - Mikha Gabriela
- Malaria Virulence and Drug Discovery Group, Burnet Institute, Melbourne, Australia
- School of Medicine, Deakin University, Geelong, Australia
| | - Ellen Ploeger
- Malaria Virulence and Drug Discovery Group, Burnet Institute, Melbourne, Australia
| | | | - Sarah C. Charnaud
- Malaria Virulence and Drug Discovery Group, Burnet Institute, Melbourne, Australia
| | - Madeline G. Dans
- Malaria Virulence and Drug Discovery Group, Burnet Institute, Melbourne, Australia
| | - Malcolm McConville
- Department of Biochemistry and Molecular Biology, Bio21 Institute of Molecular Science and Biotechnology, University of Melbourne, Melbourne, Australia
| | - Hayley E. Bullen
- Malaria Virulence and Drug Discovery Group, Burnet Institute, Melbourne, Australia
- Department of Immunology and Microbiology, University of Melbourne, Melbourne, Australia
| | - Brendan S. Crabb
- Malaria Virulence and Drug Discovery Group, Burnet Institute, Melbourne, Australia
- Department of Immunology and Microbiology, University of Melbourne, Melbourne, Australia
- Department of Immunology and Pathology, Monash University, Melbourne, Australia
| | - Paul R. Gilson
- Malaria Virulence and Drug Discovery Group, Burnet Institute, Melbourne, Australia
- Department of Immunology and Microbiology, University of Melbourne, Melbourne, Australia
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Platon L, Baker DA, Ménard D. Modified Plasmodium falciparum Ring-Stage Survival Assay with ML10 Kinase Inhibitor. Antimicrob Agents Chemother 2023; 67:e0001723. [PMID: 37098950 PMCID: PMC10190288 DOI: 10.1128/aac.00017-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Accepted: 04/10/2023] [Indexed: 04/27/2023] Open
Abstract
The ring-stage survival assay is the reference assay to measure in vitro Plasmodium falciparum artemisinin partial resistance. The main challenge of the standard protocol is to generate 0-to-3-h postinvasion ring stages (the stage least susceptible to artemisinin) from schizonts obtained by sorbitol treatment and Percoll gradient. We report here a modified protocol facilitating the production of synchronized schizonts when multiple strains are tested simultaneously, by using ML10, a protein kinase inhibitor, that reversibly blocks merozoite egress.
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Affiliation(s)
- Lucien Platon
- Institut Pasteur, Université Paris Cité, Malaria Genetics and Resistance Unit, INSERM U1201, Paris, France
- Sorbonne Université, Paris, France
- Institut Pasteur, Université Paris Cité, Malaria Parasite Biology and Vaccines Unit, Paris, France
| | - David A. Baker
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Didier Ménard
- Institut Pasteur, Université Paris Cité, Malaria Genetics and Resistance Unit, INSERM U1201, Paris, France
- Institut Pasteur, Université Paris Cité, Malaria Parasite Biology and Vaccines Unit, Paris, France
- Université de Strasbourg, Institute of Parasitology and Tropical Diseases, UR7292 Dynamics of Host-Pathogen Interactions, Strasbourg, France
- CHU Strasbourg, Laboratory of Parasitology and Medical Mycology, Strasbourg, France
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13
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Dash R, Skillman KM, Pereira L, Mascarenhas A, Dass S, Walke J, Almeida A, Fernandes M, Gomes E, White J, Chery-Karschney L, Khandeparkar A, Rathod PK, Duraisingh MT, Kanjee U. Development of a Plasmodium vivax biobank for functional ex vivo assays. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.17.533128. [PMID: 36993272 PMCID: PMC10055260 DOI: 10.1101/2023.03.17.533128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Background Plasmodium vivax is the second most prevalent cause of malaria yet remains challenging to study due to the lack of a continuous in vitro culture system, highlighting the need to establish a biobank of clinical isolates with multiple freezes per sample for use in functional assays. Different methods for cryopreserving parasite isolates were compared and subsequently the most promising one was validated. Enrichment of early- and late-stage parasites and parasite maturation were quantified to facilitate assay planning. Methods In order to compare cryopreservation protocols, nine clinical P. vivax isolates were frozen with four glycerolyte-based mixtures. Parasite recovery post thaw, post KCl-Percoll enrichment and in short-term in vitro culture was measured via slide microscopy. Enrichment of late-stage parasites by magnetic activated cell sorting (MACS) was measured. Short and long-term storage of parasites at either -80°C or liquid nitrogen were also compared. Results Of the four cryopreservation mixtures, one mixture (glycerolyte:serum:RBC at a 2.5:1.5:1 ratio) resulted in improved parasite recovery and statistically significant (P<0.05) enhancement in parasite survival in short-term in vitro culture. A parasite biobank was subsequently generated using this protocol resulting in a collection with 106 clinical isolates, each with 8 vials. The quality of the biobank was validated by measuring several factors from 47 thaws: the average reduction in parasitemia post-thaw (25.3%); the average fold enrichment post KCl-Percoll (6.65-fold); and the average percent recovery of parasites (22.0%, measured from 30 isolates). During short-term in vitro culture, robust maturation of ring stage parasites to later stages (>20% trophozoites, schizonts and gametocytes) was observed in 60.0% of isolates by 48 hours. Enrichment of mature parasite stages via MACS showed good reproducibility, with an average 30.0% post-MACS parasitemia and an average 5.30 × 10 5 parasites/vial. Finally, the effect of storage temperature was tested, and no large impacts from short-term (7 day) or long term (7 - 10 year) storage at -80°C on parasite recovery, enrichment or viability was observed. Conclusions Here, an optimized freezing method for P. vivax clinical isolates is demonstrated as a template for the generation and validation of a parasite biobank for use in functional assays.
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Barnes CBG, Dans MG, Jonsdottir TK, Crabb BS, Gilson PR. PfATP4 inhibitors in the Medicines for Malaria Venture Malaria Box and Pathogen Box block the schizont-to-ring transition by inhibiting egress rather than invasion. Front Cell Infect Microbiol 2022; 12:1060202. [PMID: 36530423 PMCID: PMC9747762 DOI: 10.3389/fcimb.2022.1060202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Accepted: 11/15/2022] [Indexed: 12/05/2022] Open
Abstract
The cation efflux pump Plasmodium falciparum ATPase 4 (PfATP4) maintains Na+ homeostasis in malaria parasites and has been implicated in the mechanism of action of many structurally diverse antimalarial agents, including >7% of the antimalarial compounds in the Medicines for Malaria Venture's 'Malaria Box' and 'Pathogen Box'. Recent screens of the 'Malaria Box' and 'Pathogen Box' revealed that many PfATP4 inhibitors prevent parasites from exiting their host red blood cell (egress) or entering new host cells (invasion), suggesting that these compounds may have additional molecular targets involved in egress or invasion. Here, we demonstrate that five PfATP4 inhibitors reduce egress but not invasion. These compounds appear to inhibit egress by blocking the activation of protein kinase G, an enzyme that, once stimulated, rapidly activates parasite egress. We establish a direct link between egress and PfATP4 function by showing that the inhibition of egress is attenuated in a Na+-depleted environment and in parasites with a mutation in pfatp4. Finally, we show that PfATP4 inhibitors induce host cell lysis when administered prior to the completion of parasite replication. Since host cell lysis mimics egress but is not followed by invasion, this phenomenon likely explains why several PfATP4 inhibitors were previously classified as invasion inhibitors. Collectively, our results confirm that PfATP4-mediated Na+ efflux is critical to the regulation of parasite egress.
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Affiliation(s)
- Claudia B. G. Barnes
- Life Sciences, Burnet Institute, Melbourne, VIC, Australia,Department of Medicine, The University of Melbourne, Melbourne, VIC, Australia
| | - Madeline G. Dans
- Life Sciences, Burnet Institute, Melbourne, VIC, Australia,School of Medicine, Deakin University, Geelong, VIC, Australia
| | - Thorey K. Jonsdottir
- Life Sciences, Burnet Institute, Melbourne, VIC, Australia,Department of Immunology and Pathology, Monash University, Melbourne, VIC, Australia
| | - Brendan S. Crabb
- Life Sciences, Burnet Institute, Melbourne, VIC, Australia,Department of Microbiology and Immunology, The University of Melbourne, Parkville, VIC, Australia,Department of Immunology and Pathology, Monash University, Melbourne, VIC, Australia
| | - Paul R. Gilson
- Life Sciences, Burnet Institute, Melbourne, VIC, Australia,Department of Microbiology and Immunology, The University of Melbourne, Parkville, VIC, Australia,*Correspondence: Paul R. Gilson,
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Ressurreição M, Moon RW, Baker DA, van Ooij C. Synchronisation of Plasmodium falciparum and P. knowlesi In Vitro Cultures Using a Highly Specific Protein Kinase Inhibitor. Methods Mol Biol 2022; 2470:101-120. [PMID: 35881342 DOI: 10.1007/978-1-0716-2189-9_10] [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: 10/16/2022]
Abstract
Synchronisation of Plasmodium cultures is essential to investigate the complexities of time-dependent events associated with the asexual blood stage of the malaria parasite life cycle. Here we describe a procedure using ML10, a highly specific inhibitor of the parasite cyclic GMP-dependent protein kinase (PKG), to attain high synchronicity of Plasmodium falciparum and P. knowlesi asexual blood-stage cultures and to obtain high levels of arrested mature schizonts as well as viable released merozoites. Additionally, we describe how to use ML10 to improve the transfection efficiency of P. falciparum parasites and also how to derive the half maximal effective concentration (EC50) of ML10 in other P. falciparum laboratory lines and clinical isolates.
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Affiliation(s)
- Margarida Ressurreição
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | - Robert William Moon
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | - David Andrew Baker
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | - Christiaan van Ooij
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK.
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Hakimi H, Asada M, Ishizaki T, Kawazu S. Isolation of viable Babesia bovis merozoites to study parasite invasion. Sci Rep 2021; 11:16959. [PMID: 34417510 PMCID: PMC8379152 DOI: 10.1038/s41598-021-96365-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2021] [Accepted: 07/31/2021] [Indexed: 12/22/2022] Open
Abstract
Babesia parasite invades exclusively red blood cell (RBC) in mammalian host and induces alterations to host cell for survival. Despite the importance of Babesia in livestock industry and emerging cases in humans, their basic biology is hampered by lack of suitable biological tools. In this study, we aimed to develop a synchronization method for Babesia bovis which causes the most pathogenic form of bovine babesiosis. Initially, we used compound 2 (C2), a specific inhibitor of cyclic GMP-dependent protein kinase (PKG), and a derivative of C2, ML10. While both inhibitors were able to prevent B. bovis egress from RBC and increased percentage of binary forms, removal of inhibitors from culture did not result in a synchronized egress of parasites. Because using PKG inhibitors alone was not efficient to induce a synchronized culture, we isolated viable and invasive B. bovis merozoites and showed dynamics of merozoite invasion and development in RBCs. Using isolated merozoites we showed that BbVEAP, VESA1-export associated protein, is essential for parasite development in the RBC while has no significant role in invasion. Given the importance of invasion for the establishment of infection, this study paves the way for finding novel antigens to be used in control strategies against bovine babesiosis.
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Affiliation(s)
- Hassan Hakimi
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido, 080-8555, Japan. .,Department of Veterinary Pathobiology, College of Veterinary Medicine, Texas A&M University, College Station, TX, USA.
| | - Masahito Asada
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido, 080-8555, Japan
| | - Takahiro Ishizaki
- Department of Protozoology, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, 852-8523, Japan
| | - Shinichiro Kawazu
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido, 080-8555, Japan.
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Abstract
All intracellular pathogens must escape (egress) from the confines of their host cell to disseminate and proliferate. The malaria parasite only replicates in an intracellular vacuole or in a cyst, and must undergo egress at four distinct phases during its complex life cycle, each time disrupting, in a highly regulated manner, the membranes or cyst wall that entrap the parasites. This Cell Science at a Glance article and accompanying poster summarises our current knowledge of the morphological features of egress across the Plasmodium life cycle, the molecular mechanisms that govern the process, and how researchers are working to exploit this knowledge to develop much-needed new approaches to malaria control. ![]()
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Affiliation(s)
- Michele S Y Tan
- Malaria Biochemistry Laboratory, The Francis Crick Institute, London NW1 1AT, UK
| | - Michael J Blackman
- Malaria Biochemistry Laboratory, The Francis Crick Institute, London NW1 1AT, UK .,Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London WC1E 7HT, UK
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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] [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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