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Dogga SK, Rop JC, Cudini J, Farr E, Dara A, Ouologuem D, Djimdé AA, Talman AM, Lawniczak MKN. A single cell atlas of sexual development in Plasmodium falciparum. Science 2024; 384:eadj4088. [PMID: 38696552 DOI: 10.1126/science.adj4088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Accepted: 03/14/2024] [Indexed: 05/04/2024]
Abstract
The developmental decision made by malaria parasites to become sexual underlies all malaria transmission. Here, we describe a rich atlas of short- and long-read single-cell transcriptomes of over 37,000 Plasmodium falciparum cells across intraerythrocytic asexual and sexual development. We used the atlas to explore transcriptional modules and exon usage along sexual development and expanded it to include malaria parasites collected from four Malian individuals naturally infected with multiple P. falciparum strains. We investigated genotypic and transcriptional heterogeneity within and among these wild strains at the single-cell level, finding differential expression between different strains even within the same host. These data are a key addition to the Malaria Cell Atlas interactive data resource, enabling a deeper understanding of the biology and diversity of transmission stages.
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Affiliation(s)
| | - Jesse C Rop
- Wellcome Sanger Institute, Hinxton CB10 1SA, UK
| | | | - Elias Farr
- Wellcome Sanger Institute, Hinxton CB10 1SA, UK
- Institute for Computational Biomedicine, University of Heidelberg, Im Neuenheimer Feld 130.3, 69120 Heidelberg, Germany
| | - Antoine Dara
- Malaria Research and Training Center (MRTC), Faculty of Pharmacy, Université des Sciences, des Techniques et des Technologies de Bamako (USTTB), Point G, P.O. Box, 1805 Bamako, Mali
| | - Dinkorma Ouologuem
- Malaria Research and Training Center (MRTC), Faculty of Pharmacy, Université des Sciences, des Techniques et des Technologies de Bamako (USTTB), Point G, P.O. Box, 1805 Bamako, Mali
| | - Abdoulaye A Djimdé
- Malaria Research and Training Center (MRTC), Faculty of Pharmacy, Université des Sciences, des Techniques et des Technologies de Bamako (USTTB), Point G, P.O. Box, 1805 Bamako, Mali
| | - Arthur M Talman
- MIVEGEC, University of Montpellier, IRD, CNRS, Montpellier, France
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2
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Hviid L, Jensen AR, Deitsch KW. PfEMP1 and var genes - Still of key importance in Plasmodium falciparum malaria pathogenesis and immunity. ADVANCES IN PARASITOLOGY 2024; 125:53-103. [PMID: 39095112 DOI: 10.1016/bs.apar.2024.02.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/04/2024]
Abstract
The most severe form of malaria, caused by infection with Plasmodium falciparum parasites, continues to be an important cause of human suffering and poverty. The P. falciparum erythrocyte membrane protein 1 (PfEMP1) family of clonally variant antigens, which mediates the adhesion of infected erythrocytes to the vascular endothelium in various tissues and organs, is a central component of the pathogenesis of the disease and a key target of the acquired immune response to malaria. Much new knowledge has accumulated since we published a systematic overview of the PfEMP1 family almost ten years ago. In this chapter, we therefore aim to summarize research progress since 2015 on the structure, function, regulation etc. of this key protein family of arguably the most important human parasite. Recent insights regarding PfEMP1-specific immune responses and PfEMP1-specific vaccination against malaria, as well as an outlook for the coming years are also covered.
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Affiliation(s)
- Lars Hviid
- Centre for translational Medicine and Parasitology, Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark; Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), Copenhagen, Denmark.
| | - Anja R Jensen
- Centre for translational Medicine and Parasitology, Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Kirk W Deitsch
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, NY, United States
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3
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Stofberg ML, Muzenda FL, Achilonu I, Strauss E, Zininga T. In silico screening of selective ATP mimicking inhibitors targeting the Plasmodium falciparum Grp94. J Biomol Struct Dyn 2024:1-12. [PMID: 38498364 DOI: 10.1080/07391102.2024.2329304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Accepted: 03/06/2024] [Indexed: 03/20/2024]
Abstract
Plasmodium falciparum parasites export more than 400 proteins to remodel the host cell environment and increase its chances of surviving and reproducing. The endoplasmic reticulum (ER) plays a central role in protein export by facilitating protein sorting and folding. The ER resident member of the Hsp90 family, glucose-regulated protein 94 (Grp94), is a molecular chaperone that facilitates the proper folding of client proteins in the ER lumen. In P. falciparum, Grp94 (PfGrp94) is essential for parasite survival, rendering it a promising anti-malarial drug target. Despite this, its druggability has not been fully explored. Consequently, this study sought to identify small molecule inhibitors targeting the PfGrp94. Potential small molecule inhibitors of PfGrp94 were designed and screened using in silico studies. Molecular docking studies indicate that two novel compounds, Compound S and Compound Z selectively bind to PfGrp94 over its human homologues. Comparatively, Compound Z had a higher affinity for PfGrp94 than Compound S. Further interrogation of the inhibitor binding using molecular dynamics (MD) analysis confirmed that Compound Z formed stable binding poses within the ATP-binding pocket of the PfGrp94 N-terminal domain (NTD) during the 250 ns simulation run. PfGrp94 interacted with Compound Z through hydrogen bonding and hydrophobic interactions with residues Asp 148, Asn 106, Gly 152, Ile 151 and Lys 113. Based on the findings of this study, Compound Z could serve as a competitive and selective inhibitor of PfGrp94 and may be useful as a starting point for the development of a potential drug for malaria.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
| | | | - Ikechukwu Achilonu
- School of Molecular and Cell Biology, University of Witwatersrand, Johannesburg, South Africa
| | - Erick Strauss
- Department of Biochemistry, University of Stellenbosch, Stellenbosch, South Africa
| | - Tawanda Zininga
- Department of Biochemistry, University of Stellenbosch, Stellenbosch, South Africa
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4
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Fierro MA, Muheljic A, Sha J, Wohlschlegel J, Beck JR. PEXEL is a proteolytic maturation site for both exported and non-exported Plasmodium proteins. mSphere 2024; 9:e0039323. [PMID: 38334391 PMCID: PMC10900883 DOI: 10.1128/msphere.00393-23] [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: 07/13/2023] [Accepted: 01/10/2024] [Indexed: 02/10/2024] Open
Abstract
Obligate intracellular malaria parasites dramatically remodel their erythrocyte host through effector protein export to create a niche for survival. Most exported proteins contain a pentameric Plasmodium export element (PEXEL)/host-targeting motif that is cleaved in the parasite ER by the aspartic protease Plasmepsin V (PMV). This processing event exposes a mature N terminus required for translocation into the host cell and is not known to occur in non-exported proteins. Here, we report that the non-exported parasitophorous vacuole protein UIS2 contains a bona fide PEXEL motif that is processed in the P. falciparum blood stage. While the N termini of exported proteins containing the PEXEL and immediately downstream ~10 residues are sufficient to mediate translocation into the RBC, the equivalent UIS2 N terminus does not promote the export of a reporter. Curiously, the UIS2 PEXEL contains an unusual aspartic acid at the fourth position, which constitutes the extreme N-terminal residue following PEXEL cleavage (P1', RIL↓DE). Using a series of chimeric reporter fusions, we show that Asp at P1' is permissive for PMV processing but abrogates export. Moreover, mutation of this single UIS2 residue to alanine enables export, reinforcing that the mature N terminus mediates export, not PEXEL processing per se. Prompted by this observation, we further show that PEXEL sequences in the N termini of other non-exported rhoptry proteins are also processed, suggesting that PMV may be a more general secretory maturase than previously appreciated, similar to orthologs in related apicomplexans. Our findings provide new insight into the unique N-terminal constraints that mark proteins for export.IMPORTANCEHost erythrocyte remodeling by malaria parasite-exported effector proteins is critical to parasite survival and disease pathogenesis. In the deadliest malaria parasite Plasmodium falciparum, most exported proteins undergo proteolytic maturation via recognition of the pentameric Plasmodium export element (PEXEL)/host-targeting motif by the aspartic protease Plasmepsin V, which exposes a mature N terminus that is conducive for export into the erythrocyte host cell. While PEXEL processing is considered a unique mark of exported proteins, we demonstrate that PEXEL motifs are present and processed in non-exported proteins. Importantly, we show that specific residues at the variable fourth position of the PEXEL motif inhibit export despite being permissive for processing, reinforcing that features of the mature N terminus, and not PEXEL cleavage, identify cargo for export. This opens the door to further inquiry into the nature and evolution of the PEXEL motif.
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Affiliation(s)
- Manuel A. Fierro
- Department of Biomedical Sciences, Iowa State University, Ames, lowa, USA
| | - Ajla Muheljic
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, Iowa, USA
| | - Jihui Sha
- Department of Biological Chemistry, University of California, Los Angeles, California, USA
| | - James Wohlschlegel
- Department of Biological Chemistry, University of California, Los Angeles, California, USA
| | - Josh R. Beck
- Department of Biomedical Sciences, Iowa State University, Ames, lowa, USA
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, Iowa, USA
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5
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Gabriela M, Barnes CBG, Leong D, Sleebs BE, Schneider MP, Littler DR, Crabb BS, de Koning‐Ward TF, Gilson PR. Sequence elements within the PEXEL motif and its downstream region modulate PTEX-dependent protein export in Plasmodium falciparum. Traffic 2024; 25:e12922. [PMID: 37926971 PMCID: PMC10952997 DOI: 10.1111/tra.12922] [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: 03/23/2023] [Revised: 08/23/2023] [Accepted: 10/15/2023] [Indexed: 11/07/2023]
Abstract
The parasite Plasmodium falciparum causes the most severe form of malaria and to invade and replicate in red blood cells (RBCs), it exports hundreds of proteins across the encasing parasitophorous vacuole membrane (PVM) into this host cell. The exported proteins help modify the RBC to support rapid parasite growth and avoidance of the human immune system. Most exported proteins possess a conserved Plasmodium export element (PEXEL) motif with the consensus RxLxE/D/Q amino acid sequence, which acts as a proteolytic cleavage recognition site within the parasite's endoplasmic reticulum (ER). Cleavage occurs after the P1 L residue and is thought to help release the protein from the ER so it can be putatively escorted by the HSP101 chaperone to the parasitophorous vacuole space surrounding the intraerythrocytic parasite. HSP101 and its cargo are then thought to assemble with the rest of a Plasmodium translocon for exported proteins (PTEX) complex, that then recognises the xE/D/Q capped N-terminus of the exported protein and translocates it across the vacuole membrane into the RBC compartment. Here, we present evidence that supports a dual role for the PEXEL's conserved P2 ' position E/Q/D residue, first, for plasmepsin V cleavage in the ER, and second, for efficient PTEX mediated export across the PVM into the RBC. We also present evidence that the downstream 'spacer' region separating the PEXEL motif from the folded functional region of the exported protein controls cargo interaction with PTEX as well. The spacer must be of a sufficient length and permissive amino acid composition to engage the HSP101 unfoldase component of PTEX to be efficiently translocated into the RBC compartment.
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Affiliation(s)
- Mikha Gabriela
- Malaria Virulence and Drug Discovery GroupBurnet InstituteMelbourneVictoriaAustralia
- School of MedicineDeakin UniversityGeelongVictoriaAustralia
| | - Claudia B. G. Barnes
- Malaria Virulence and Drug Discovery GroupBurnet InstituteMelbourneVictoriaAustralia
| | - Dickson Leong
- Malaria Virulence and Drug Discovery GroupBurnet InstituteMelbourneVictoriaAustralia
| | - Brad E. Sleebs
- The Walter and Eliza Hall Institute of Medical ResearchParkvilleVictoriaAustralia
- Department of Medical BiologyThe University of MelbourneParkvilleVictoriaAustralia
| | | | - Dene R. Littler
- Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery InstituteMonash UniversityClaytonVictoriaAustralia
| | - Brendan S. Crabb
- Malaria Virulence and Drug Discovery GroupBurnet InstituteMelbourneVictoriaAustralia
- Department of Medical BiologyThe University of MelbourneParkvilleVictoriaAustralia
- Department of Microbiology and ImmunologyUniversity of MelbourneParkvilleVictoriaAustralia
- Department of ImmunologyMonash UniversityMelbourneVictoriaAustralia
| | - Tania F. de Koning‐Ward
- School of MedicineDeakin UniversityGeelongVictoriaAustralia
- Institute for Mental and Physical Health and Clinical Translation (IMPACT)Deakin UniversityGeelongVictoriaAustralia
| | - Paul R. Gilson
- Malaria Virulence and Drug Discovery GroupBurnet InstituteMelbourneVictoriaAustralia
- Department of Microbiology and ImmunologyUniversity of MelbourneParkvilleVictoriaAustralia
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6
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Bailey BL, Nguyen W, Cowman AF, Sleebs BE. Chemo-proteomics in antimalarial target identification and engagement. Med Res Rev 2023; 43:2303-2351. [PMID: 37232495 PMCID: PMC10947479 DOI: 10.1002/med.21975] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 04/24/2023] [Accepted: 05/08/2023] [Indexed: 05/27/2023]
Abstract
Humans have lived in tenuous battle with malaria over millennia. Today, while much of the world is free of the disease, areas of South America, Asia, and Africa still wage this war with substantial impacts on their social and economic development. The threat of widespread resistance to all currently available antimalarial therapies continues to raise concern. Therefore, it is imperative that novel antimalarial chemotypes be developed to populate the pipeline going forward. Phenotypic screening has been responsible for the majority of the new chemotypes emerging in the past few decades. However, this can result in limited information on the molecular target of these compounds which may serve as an unknown variable complicating their progression into clinical development. Target identification and validation is a process that incorporates techniques from a range of different disciplines. Chemical biology and more specifically chemo-proteomics have been heavily utilized for this purpose. This review provides an in-depth summary of the application of chemo-proteomics in antimalarial development. Here we focus particularly on the methodology, practicalities, merits, and limitations of designing these experiments. Together this provides learnings on the future use of chemo-proteomics in antimalarial development.
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Affiliation(s)
- Brodie L. Bailey
- The Walter and Eliza Hall Institute of Medical ResearchMelbourneVictoriaAustralia
- Department of Medical BiologyThe University of MelbourneMelbourneVictoriaAustralia
| | - William Nguyen
- The Walter and Eliza Hall Institute of Medical ResearchMelbourneVictoriaAustralia
- Department of Medical BiologyThe University of MelbourneMelbourneVictoriaAustralia
| | - Alan F. Cowman
- The Walter and Eliza Hall Institute of Medical ResearchMelbourneVictoriaAustralia
- Department of Medical BiologyThe University of MelbourneMelbourneVictoriaAustralia
| | - Brad E. Sleebs
- The Walter and Eliza Hall Institute of Medical ResearchMelbourneVictoriaAustralia
- Department of Medical BiologyThe University of MelbourneMelbourneVictoriaAustralia
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7
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Hasan MM, Polino AJ, Mukherjee S, Vaupel B, Goldberg DE. The mature N-termini of Plasmodium effector proteins confer specificity of export. mBio 2023; 14:e0121523. [PMID: 37646514 PMCID: PMC10653839 DOI: 10.1128/mbio.01215-23] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Accepted: 07/10/2023] [Indexed: 09/01/2023] Open
Abstract
IMPORTANCE Malaria parasites export hundreds of proteins to the cytoplasm of the host red blood cells for their survival. A five amino acid sequence, called the PEXEL motif, is conserved among many exported proteins and is thought to be a signal for export. However, the motif is cleaved inside the endoplasmic reticulum of the parasite, and mature proteins starting from the fourth PEXEL residue travel to the parasite periphery for export. We showed that the PEXEL motif is dispensable for export as long as identical mature proteins can be efficiently produced via alternative means in the ER. We also showed that the exported and non-exported proteins are differentiated at the parasite periphery based on their mature N-termini; however, any discernible export signal within that region remained cryptic. Our study resolves a longstanding paradox in PEXEL protein trafficking.
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Affiliation(s)
- Muhammad M. Hasan
- Division of Infectious Diseases, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Alexander J. Polino
- Division of Infectious Diseases, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Sumit Mukherjee
- Division of Infectious Diseases, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Barbara Vaupel
- Division of Infectious Diseases, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Daniel E. Goldberg
- Division of Infectious Diseases, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
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8
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Feldman TP, Ryan Y, Egan ES. Plasmodium falciparum infection of human erythroblasts induces transcriptional changes associated with dyserythropoiesis. Blood Adv 2023; 7:5496-5509. [PMID: 37493969 PMCID: PMC10515311 DOI: 10.1182/bloodadvances.2023010844] [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: 05/30/2023] [Revised: 07/24/2023] [Accepted: 07/24/2023] [Indexed: 07/27/2023] Open
Abstract
During development down the erythroid lineage, hematopoietic stem cells undergo dramatic changes to cellular morphology and function in response to a complex and tightly regulated program of gene expression. In malaria infection, Plasmodium spp parasites accumulate in the bone marrow parenchyma, and emerging evidence suggests erythroblastic islands are a protective site for parasite development into gametocytes. Although it has been observed that Plasmodium falciparum infection in late-stage erythroblasts can delay terminal erythroid differentiation and enucleation, the mechanism(s) underlying this phenomenon are unknown. Here, we apply RNA sequencing after fluorescence-activated cell sorting of infected erythroblasts to identify transcriptional responses to direct and indirect interaction with P falciparum. Four developmental stages of erythroid cells were analyzed: proerythroblast, basophilic erythroblast, polychromatic erythroblast, and orthochromatic erythroblast. We found extensive transcriptional changes in infected erythroblasts compared with that in uninfected cells in the same culture, including dysregulation of genes involved in erythroid proliferation and developmental processes. Although some indicators of cellular oxidative and proteotoxic stress were common across all stages of erythropoiesis, many responses were specific to cellular processes associated with developmental stage. Together, our results evidence multiple possible avenues by which parasite infection can induce dyserythropoiesis at specific points along the erythroid continuum, advancing our understanding of the molecular determinants of malaria anemia.
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Affiliation(s)
- Tamar P. Feldman
- Department of Pediatrics, Stanford University School of Medicine, Stanford, CA
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA
| | - Yana Ryan
- Stanford Center for Genomics and Personalized Medicine, Stanford University School of Medicine, Stanford, CA
| | - Elizabeth S. Egan
- Department of Pediatrics, Stanford University School of Medicine, Stanford, CA
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA
- Chan Zuckerberg Biohub, San Francisco, CA
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9
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Ling DB, Nguyen W, Looker O, Razook Z, McCann K, Barry AE, Scheurer C, Wittlin S, Famodimu MT, Delves MJ, Bullen HE, Crabb BS, Sleebs BE, Gilson PR. A Pyridyl-Furan Series Developed from the Open Global Health Library Block Red Blood Cell Invasion and Protein Trafficking in Plasmodium falciparum through Potential Inhibition of the Parasite's PI4KIIIB Enzyme. ACS Infect Dis 2023; 9:1695-1710. [PMID: 37639221 PMCID: PMC10496428 DOI: 10.1021/acsinfecdis.3c00138] [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: 03/20/2023] [Indexed: 08/29/2023]
Abstract
With the resistance increasing to current antimalarial medicines, there is an urgent need to discover new drug targets and to develop new medicines against these targets. We therefore screened the Open Global Health Library of Merck KGaA, Darmstadt, Germany, of 250 compounds against the asexual blood stage of the deadliest malarial parasite Plasmodium falciparum, from which eight inhibitors with low micromolar potency were found. Due to its combined potencies against parasite growth and inhibition of red blood cell invasion, the pyridyl-furan compound OGHL250 was prioritized for further optimization. The potency of the series lead compound (WEHI-518) was improved 250-fold to low nanomolar levels against parasite blood-stage growth. Parasites selected for resistance to a related compound, MMV396797, were also resistant to WEHI-518 as well as KDU731, an inhibitor of the phosphatidylinositol kinase PfPI4KIIIB, suggesting that this kinase is the target of the pyridyl-furan series. Inhibition of PfPI4KIIIB blocks multiple stages of the parasite's life cycle and other potent inhibitors are currently under preclinical development. MMV396797-resistant parasites possess an E1316D mutation in PfPKI4IIIB that clusters with known resistance mutations of other inhibitors of the kinase. Building upon earlier studies that showed that PfPI4KIIIB inhibitors block the development of the invasive merozoite parasite stage, we show that members of the pyridyl-furan series also block invasion and/or the conversion of merozoites into ring-stage intracellular parasites through inhibition of protein secretion and export into red blood cells.
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Affiliation(s)
- Dawson B. Ling
- Burnet Institute,
Melbourne, Victoria3004, Australia
- Department of Microbiology and Immunology,
University of Melbourne, Melbourne, Victoria3010,
Australia
| | - William Nguyen
- The Walter and Eliza Hall Institute of
Medical Research, Melbourne, Victoria3052,
Australia
- Department of Medical Biology, The
University of Melbourne, Parkville, Victoria3010,
Australia
| | - Oliver Looker
- Burnet Institute,
Melbourne, Victoria3004, Australia
| | - Zahra Razook
- Burnet Institute,
Melbourne, Victoria3004, Australia
- School of Medicine and Institute for Mental and
Physical Health and Clinical Translation, Deakin University,
Waurn Ponds, Victoria3216, Australia
| | - Kirsty McCann
- Burnet Institute,
Melbourne, Victoria3004, Australia
- School of Medicine and Institute for Mental and
Physical Health and Clinical Translation, Deakin University,
Waurn Ponds, Victoria3216, Australia
| | - Alyssa E. Barry
- Burnet Institute,
Melbourne, Victoria3004, Australia
- School of Medicine and Institute for Mental and
Physical Health and Clinical Translation, Deakin University,
Waurn Ponds, Victoria3216, Australia
| | - Christian Scheurer
- Swiss Tropical and Public Health
Institute, Allschwil, 4123Switzerland
- University of Basel, Basel,
4001Switzerland
| | - Sergio Wittlin
- Swiss Tropical and Public Health
Institute, Allschwil, 4123Switzerland
- University of Basel, Basel,
4001Switzerland
| | - Mufuliat Toyin Famodimu
- Department of Infection Biology, Faculty of Infectious
Diseases, London School of Hygiene and Tropical Medicine, Kepel
Street, London, WC1E 7HT, U.K.
| | - Michael J Delves
- Department of Infection Biology, Faculty of Infectious
Diseases, London School of Hygiene and Tropical Medicine, Kepel
Street, London, WC1E 7HT, U.K.
| | - Hayley E. Bullen
- Burnet Institute,
Melbourne, Victoria3004, Australia
- Department of Microbiology and Immunology,
University of Melbourne, Melbourne, Victoria3010,
Australia
| | - Brendan S. Crabb
- Burnet Institute,
Melbourne, Victoria3004, Australia
- Department of Microbiology and Immunology,
University of Melbourne, Melbourne, Victoria3010,
Australia
- Department of Immunology and Pathology,
Monash University, Melbourne, Victoria3800,
Australia
| | - Brad E. Sleebs
- The Walter and Eliza Hall Institute of
Medical Research, Melbourne, Victoria3052,
Australia
- Department of Medical Biology, The
University of Melbourne, Parkville, Victoria3010,
Australia
| | - Paul R. Gilson
- Burnet Institute,
Melbourne, Victoria3004, Australia
- Department of Microbiology and Immunology,
University of Melbourne, Melbourne, Victoria3010,
Australia
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10
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Fierro MA, Muheljic A, Sha J, Wohlschlegel JA, Beck JR. PEXEL is a proteolytic maturation site for both exported and non-exported Plasmodium proteins. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.12.548774. [PMID: 37503245 PMCID: PMC10369990 DOI: 10.1101/2023.07.12.548774] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
Obligate intracellular malaria parasites dramatically remodel their erythrocyte host through effector protein export to create a niche for survival. Most exported proteins contain a pentameric P lasmodium ex port el ement (PEXEL)/Host Targeting Motif that is cleaved in the parasite ER by the aspartic protease Plasmepsin V (PMV). This processing event exposes a mature N-terminus required for translocation into the host cell and is not known to occur in non-exported proteins. Here we report that the non-exported parasitophorous vacuole protein UIS2 contains a bona fide PEXEL motif that is processed in the P. falciparum blood-stage. While the N-termini of exported proteins containing the PEXEL and immediately downstream ∼10 residues is sufficient to mediate translocation into the RBC, the equivalent UIS2 N-terminus does not promote export of a reporter. Curiously, the UIS2 PEXEL contains an unusual aspartic acid at the fourth position which constitutes the extreme N-terminal residue following PEXEL cleavage (P1', RILτDE). Using a series of chimeric reporter fusions, we show that Asp at P1' is permissive for PMV processing but abrogates export. Moreover, mutation of this single UIS2 residue to alanine enables export, reinforcing that the mature N-terminus mediates export, not PEXEL processing per se . Prompted by this observation, we further show that PEXEL sequences in the N-termini of other non-exported rhoptry proteins are also processed, suggesting that PMV may be a more general secretory maturase than previously appreciated, similar to orthologs in related apicomplexans. Our findings provide new insight into the unique N-terminal constraints that mark proteins for export. Importance Host erythrocyte remodeling by malaria parasite exported effector proteins is critical to parasite survival and disease pathogenesis. In the deadliest malaria parasite Plasmodium falciparum , most exported proteins undergo proteolytic maturation via recognition of the pentameric P lasmodium ex port el ement (PEXEL)/Host Targeting motif by the aspartic protease Plasmepsin V (PMV) which exposes a mature N-terminus that is conducive for export into the erythrocyte host cell. While PEXEL processing is considered a unique mark of exported proteins, we demonstrate PEXEL motifs are present and processed in non-exported proteins. Importantly, we show that specific residues at the variable fourth position of the PEXEL motif inhibit export despite being permissive for processing by PMV, reinforcing that features of the mature N-terminus, and not PEXEL cleavage, identify cargo for export cargo. This opens the door to further inquiry into the nature and evolution of the PEXEL motif.
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11
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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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12
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Parkyn Schneider M, Looker O, Rebelo M, Khoury DS, Dixon MWA, Oeuvray C, Crabb BS, McCarthy J, Gilson PR. The delayed bloodstream clearance of Plasmodium falciparum parasites after M5717 treatment is attributable to the inability to modify their red blood cell hosts. Front Cell Infect Microbiol 2023; 13:1211613. [PMID: 37457953 PMCID: PMC10340534 DOI: 10.3389/fcimb.2023.1211613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Accepted: 06/14/2023] [Indexed: 07/18/2023] Open
Abstract
M5717 is a promising antimalarial drug under development that acts against multiple stages of the life cycle of Plasmodium parasites by inhibiting the translation elongation factor 2 (PfeEF2), thereby preventing protein synthesis. The parasite clearance profile after drug treatment in preclinical studies in mice, and clinical trials in humans showed a notable delayed clearance phenotype whereby parasite infected red blood cells (iRBCs) persisted in the bloodstream for a significant period before eventual clearance. In a normal P. falciparum infection iRBCs sequester in the deep circulation by cytoadherence, allowing them to avoid surveillance and clearance in the spleen. We found that M5717 blocks parasite modification of their host red blood cells (RBCs) by preventing synthesis of new exported proteins, rather than by directly blocking the export of these proteins into the RBC compartment. Using in vitro models, we demonstrated that M5717 treated ring/trophozoite stage iRBCs became less rigid, and cytoadhered less well compared to untreated iRBCs. This indicates that in vivo persistence of M5717 treated iRBCs in the bloodstream is likely due to reduced cytoadherence and splenic clearance.
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Affiliation(s)
| | | | - Maria Rebelo
- QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia
| | - David S. Khoury
- Kirby Institute, University of New South Wales, Sydney, NSW, Australia
| | | | | | - Brendan S. Crabb
- Burnet Institute, Melbourne, VIC, Australia
- University of Melbourne, Melbourne, VIC, Australia
- Monash University, Melbourne, VIC, Australia
| | | | - Paul R. Gilson
- Burnet Institute, Melbourne, VIC, Australia
- University of Melbourne, Melbourne, VIC, Australia
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13
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Pires CV, Oberstaller J, Wang C, Casandra D, Zhang M, Chawla J, Adapa SR, Otto TD, Ferdig MT, Rayner JC, Jiang RHY, Adams JH. Chemogenomic Profiling of a Plasmodium falciparum Transposon Mutant Library Reveals Shared Effects of Dihydroartemisinin and Bortezomib on Lipid Metabolism and Exported Proteins. Microbiol Spectr 2023; 11:e0501422. [PMID: 37067430 PMCID: PMC10269874 DOI: 10.1128/spectrum.05014-22] [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: 12/06/2022] [Accepted: 03/21/2023] [Indexed: 04/18/2023] Open
Abstract
The antimalarial activity of the frontline drug artemisinin involves generation of reactive oxygen species (ROS) leading to oxidative damage of parasite proteins. To achieve homeostasis and maintain protein quality control in the overwhelmed parasite, the ubiquitin-proteasome system kicks in. Even though molecular markers for artemisinin resistance like pfkelch13 have been identified, the intricate network of mechanisms driving resistance remains to be elucidated. Here, we report a forward genetic screening strategy that enables a broader identification of genetic factors responsible for altering sensitivity to dihydroartemisinin (DHA) and a proteasome inhibitor, bortezomib (BTZ). Using a library of isogenic piggyBac mutants in P. falciparum, we defined phenotype-genotype associations influencing drug responses and highlighted shared mechanisms between the two processes, which mainly included proteasome-mediated degradation and the lipid metabolism genes. Additional transcriptomic analysis of a DHA/BTZ-sensitive piggyBac mutant showed it is possible to find differences between the two response mechanisms on the specific components for regulation of the exportome. Our results provide further insight into the molecular mechanisms of antimalarial drug resistance. IMPORTANCE Malaria control is seriously threatened by the emergence and spread of Plasmodium falciparum resistance to the leading antimalarial, artemisinin. The potent killing activity of artemisinin results from oxidative damage unleashed by free heme activation released by hemoglobin digestion. Although the ubiquitin-proteasome system is considered critical for parasite survival of this toxicity, the diverse genetic changes linked to artemisinin resistance are complex and, so far, have not included the ubiquitin-proteasome system. In this study, we use a systematic forward genetic approach by screening a library of P. falciparum random piggyBac mutants to decipher the genetic factors driving malaria parasite responses to the oxidative stress caused by antimalarial drugs. This study compares phenotype-genotype associations influencing dihydroartemisinin responses with the proteasome inhibitor bortezomib to delineate the role of ubiquitin-proteasome system. Our study highlights shared and unique pathways from the complex array of molecular processes critical for P. falciparum survival resulting from the oxidative damage of artemisinin.
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Affiliation(s)
- Camilla Valente Pires
- Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, Tampa, Florida, USA
- USF Genomics Program, College of Public Health, University of South Florida, Tampa, Florida, USA
| | - Jenna Oberstaller
- Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, Tampa, Florida, USA
- USF Genomics Program, College of Public Health, University of South Florida, Tampa, Florida, USA
| | - Chengqi Wang
- Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, Tampa, Florida, USA
- USF Genomics Program, College of Public Health, University of South Florida, Tampa, Florida, USA
| | - Debora Casandra
- Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, Tampa, Florida, USA
- USF Genomics Program, College of Public Health, University of South Florida, Tampa, Florida, USA
| | - Min Zhang
- Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, Tampa, Florida, USA
- USF Genomics Program, College of Public Health, University of South Florida, Tampa, Florida, USA
| | - Jyotsna Chawla
- Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, Tampa, Florida, USA
- USF Genomics Program, College of Public Health, University of South Florida, Tampa, Florida, USA
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida, United States
| | - Swamy Rakesh Adapa
- Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, Tampa, Florida, USA
- USF Genomics Program, College of Public Health, University of South Florida, Tampa, Florida, USA
| | - Thomas D. Otto
- Institute of Infection, Immunity and Inflammation, MVLS, University of Glasgow, Glasgow, United Kingdom
| | - Michael T. Ferdig
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, USA
| | - Julian C. Rayner
- Cambridge Institute for Medical Research, Cambridge Biomedical Campus, University of Cambridge, Cambridge, United Kingdom
| | - Rays H. Y. Jiang
- Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, Tampa, Florida, USA
- USF Genomics Program, College of Public Health, University of South Florida, Tampa, Florida, USA
| | - John H. Adams
- Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, Tampa, Florida, USA
- USF Genomics Program, College of Public Health, University of South Florida, Tampa, Florida, USA
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14
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Feldman TP, Ryan Y, Egan ES. Plasmodium falciparum infection of human erythroblasts induces transcriptional changes associated with dyserythropoiesis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.23.538003. [PMID: 37398027 PMCID: PMC10312461 DOI: 10.1101/2023.04.23.538003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
During development down the erythroid lineage, hematopoietic stem cells undergo dramatic changes to cellular morphology and function in response to a complex and tightly regulated program of gene expression. In malaria infection, Plasmodium spp . parasites accumulate in the bone marrow parenchyma, and emerging evidence suggests erythroblastic islands are a protective site for parasite development into gametocytes. While it has been observed that Plasmodium falciparum infection of late-stage erythroblasts can delay terminal erythroid differentiation and enucleation, the mechanism(s) underlying this phenomenon are unknown. Here, we apply RNA-seq after fluorescence-activated cell sorting (FACS) of infected erythroblasts to identify transcriptional responses to direct and indirect interaction with Plasmodium falciparum . Four developmental stages of erythroid cells were analyzed: proerythroblast, basophilic erythroblast, polychromatic erythroblast, and orthochromatic erythroblast. We found extensive transcriptional changes in infected erythroblasts compared to uninfected cells in the same culture, including dysregulation of genes involved in erythroid proliferation and developmental processes. Whereas some indicators of cellular oxidative and proteotoxic stress were common across all stages of erythropoiesis, many responses were specific to cellular processes associated with developmental stage. Together, our results evidence multiple possible avenues by which parasite infection can induce dyserythropoiesis at specific points along the erythroid continuum, advancing our understanding of the molecular determinants of malaria anemia. Key Points Erythroblasts at different stages of differentiation have distinct responses to infection by Plasmodium falciparum . P. falciparum infection of erythroblasts alters expression of genes related to oxidative and proteotoxic stress and erythroid development.
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15
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Down the membrane hole: Ion channels in protozoan parasites. PLoS Pathog 2022; 18:e1011004. [PMID: 36580479 PMCID: PMC9799330 DOI: 10.1371/journal.ppat.1011004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Parasitic diseases caused by protozoans are highly prevalent around the world, disproportionally affecting developing countries, where coinfection with other microorganisms is common. Control and treatment of parasitic infections are constrained by the lack of specific and effective drugs, plus the rapid emergence of resistance. Ion channels are main drug targets for numerous diseases, but their potential against protozoan parasites is still untapped. Ion channels are membrane proteins expressed in all types of cells, allowing for the flow of ions between compartments, and regulating cellular functions such as membrane potential, excitability, volume, signaling, and death. Channels and transporters reside at the interface between parasites and their hosts, controlling nutrient uptake, viability, replication, and infectivity. To understand how ion channels control protozoan parasites fate and to evaluate their suitability for therapeutics, we must deepen our knowledge of their structure, function, and modulation. However, methodological approaches commonly used in mammalian cells have proven difficult to apply in protozoans. This review focuses on ion channels described in protozoan parasites of clinical relevance, mainly apicomplexans and trypanosomatids, highlighting proteins for which molecular and functional evidence has been correlated with their physiological functions.
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16
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Hakimi H, Yamagishi J, Kawazu SI, Asada M. Advances in understanding red blood cell modifications by Babesia. PLoS Pathog 2022; 18:e1010770. [PMID: 36107982 PMCID: PMC9477259 DOI: 10.1371/journal.ppat.1010770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Babesia are tick-borne protozoan parasites that can infect livestock, pets, wildlife animals, and humans. In the mammalian host, they invade and multiply within red blood cells (RBCs). To support their development as obligate intracellular parasites, Babesia export numerous proteins to modify the RBC during invasion and development. Such exported proteins are likely important for parasite survival and pathogenicity and thus represent candidate drug or vaccine targets. The availability of complete genome sequences and the establishment of transfection systems for several Babesia species have aided the identification and functional characterization of exported proteins. Here, we review exported Babesia proteins; discuss their functions in the context of immune evasion, cytoadhesion, and nutrient uptake; and highlight possible future topics for research and application in this field.
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Affiliation(s)
- Hassan Hakimi
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido, Japan
- Department of Veterinary Pathobiology, College of Veterinary Medicine, Texas A&M University, College Station, Texas, United States of America
- * E-mail: (HH); (MA)
| | - Junya Yamagishi
- Division of Collaboration and Education, International Institute for Zoonosis Control, Hokkaido University, Sapporo, Japan
| | - Shin-ichiro Kawazu
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido, Japan
| | - Masahito Asada
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido, Japan
- * E-mail: (HH); (MA)
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17
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Looker O, Dans MG, Bullen HE, Sleebs BE, Crabb BS, Gilson PR. The Medicines for Malaria Venture Malaria Box contains inhibitors of protein secretion in
Plasmodium falciparum
blood stage parasites. Traffic 2022; 23:442-461. [PMID: 36040075 PMCID: PMC9543830 DOI: 10.1111/tra.12862] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 07/17/2022] [Accepted: 07/26/2022] [Indexed: 11/27/2022]
Abstract
Plasmodium falciparum parasites which cause malaria, traffic hundreds of proteins into the red blood cells (RBCs) they infect. These exported proteins remodel their RBCs enabling host immune evasion through processes such as cytoadherence that greatly assist parasite survival. As resistance to all current antimalarial compounds is rising new compounds need to be identified and those that could inhibit parasite protein secretion and export would both rapidly reduce parasite virulence and ultimately lead to parasite death. To identify compounds that inhibit protein export we used transgenic parasites expressing an exported nanoluciferase reporter to screen the Medicines for Malaria Venture Malaria Box of 400 antimalarial compounds with mostly unknown targets. The most potent inhibitor identified in this screen was MMV396797 whose application led to export inhibition of both the reporter and endogenous exported proteins. MMV396797 mediated blockage of protein export and slowed the rigidification and cytoadherence of infected RBCs—modifications which are both mediated by parasite‐derived exported proteins. Overall, we have identified a new protein export inhibitor in P. falciparum whose target though unknown, could be developed into a future antimalarial that rapidly inhibits parasite virulence before eliminating parasites from the host.
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Affiliation(s)
| | - Madeline G. Dans
- Burnet Institute Melbourne Australia
- School of Medicine Deakin University Geelong Australia
| | - Hayley E. Bullen
- Burnet Institute Melbourne Australia
- Department of Immunology and Microbiology University of Melbourne Melbourne Australia
| | - Brad E. Sleebs
- The Walter and Eliza Hall Institute of Medical Research Parkville Victoria Australia
- Department of Medical Biology The University of Melbourne Parkville Victoria Australia
| | - Brendan S. Crabb
- 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
- Burnet Institute Melbourne Australia
- Department of Immunology and Microbiology University of Melbourne Melbourne Australia
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18
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Shakya B, Kilili GK, Wang L, Nakayasu ES, LaCount DJ. Identification of Exported Plasmodium falciparum Proteins That Bind to the Erythrocyte Cytoskeleton. Microorganisms 2022; 10:1438. [PMID: 35889157 PMCID: PMC9320996 DOI: 10.3390/microorganisms10071438] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 07/11/2022] [Accepted: 07/13/2022] [Indexed: 11/28/2022] Open
Abstract
Plasmodium proteins are exported to the erythrocyte cytoplasm to create an environment that supports parasite replication. Although hundreds of proteins are predicted to be exported through Plasmodium export element (PEXEL)-dependent and -independent mechanisms, the functions of exported proteins are largely uncharacterized. In this study, we used a biochemical screening approach to identify putative exported P. falciparum proteins that bound to inside-out vesicles prepared from erythrocytes. Out of 69 P. falciparum PEXEL-motif proteins tested, 18 bound to inside-out vesicles (IOVs) in two or more independent assays. Using co-affinity purifications followed by mass spectrometry, pairwise co-purification experiments, and the split-luciferase assay, we identified 31 putative protein-protein interactions between erythrocyte cytoskeletal proteins and predicted exported P. falciparum proteins. We further showed that PF3D7_1401600 binds to the spectrin-binding domain of erythrocyte ankyrin via its MESA erythrocyte cytoskeleton binding (MEC) motif and to the N-terminal domains of ankyrin and 4.1R through a fragment that required an intact Plasmodium helical interspersed sub-telomeric (PHIST) domain. Introduction of PF3D7_1401600 into erythrocyte ghosts increased retention in the microsphiltration assay, consistent with previous data that reported a reduction of rigidity in red blood cells infected with PF3D7_1401600-deficient parasites.
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Affiliation(s)
- Bikash Shakya
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN 47907, USA; (B.S.); (G.K.K.); (L.W.)
| | - Geoffrey Kimiti Kilili
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN 47907, USA; (B.S.); (G.K.K.); (L.W.)
| | - Ling Wang
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN 47907, USA; (B.S.); (G.K.K.); (L.W.)
| | - Ernesto S. Nakayasu
- Bindley Bioscience Center, Purdue University, West Lafayette, IN 47907, USA;
- Pacific Northwest National Laboratory, Biological Sciences Division, Richland, WA 99352, USA
| | - Douglas J. LaCount
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN 47907, USA; (B.S.); (G.K.K.); (L.W.)
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19
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Epigenetics of malaria parasite nutrient uptake, but why? Trends Parasitol 2022; 38:618-628. [PMID: 35641406 PMCID: PMC9283302 DOI: 10.1016/j.pt.2022.05.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Revised: 05/01/2022] [Accepted: 05/10/2022] [Indexed: 11/23/2022]
Abstract
The conserved plasmodial surface anion channel (PSAC) mediates nutrient uptake by bloodstream malaria parasites and is an antimalarial target. This pathogen-associated channel is linked to the clag multigene family, which is variably expanded in Plasmodium spp. Member genes are under complex epigenetic regulation, with the clag3 genes of the human P. falciparum pathogen exhibiting monoallelic transcription and mutually exclusive surface exposure on infected erythrocytes. While other multigene families use monoallelic expression to evade host immunity, the reasons of epigenetic control of clag genes are unclear. I consider existing models and their implications for nutrient acquisition and immune evasion. Understanding the reasons for epigenetic regulation of PSAC-mediated nutrient uptake will help clarify host-pathogen interactions and guide development of therapies resistant to allele switching.
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20
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Bullen HE, Sanders PR, Dans MG, Jonsdottir TK, Riglar DT, Looker O, Palmer CS, Kouskousis B, Charnaud SC, Triglia T, Gabriela M, Schneider MP, Chan J, de Koning‐Ward TF, Baum J, Kazura JW, Beeson JG, Cowman AF, Gilson PR, Crabb BS. The
Plasmodium falciparum
parasitophorous vacuole protein
P113
interacts with the parasite protein export machinery and maintains normal vacuole architecture. Mol Microbiol 2022; 117:1245-1262. [PMID: 35403274 PMCID: PMC9544671 DOI: 10.1111/mmi.14904] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 03/31/2022] [Accepted: 04/05/2022] [Indexed: 11/29/2022]
Affiliation(s)
- Hayley E. Bullen
- Burnet Institute 85 Commercial Road Prahran Australia
- Department of Microbiology and Immunology University of Melbourne Parkville Australia
| | | | - Madeline G. Dans
- Burnet Institute 85 Commercial Road Prahran Australia
- School of Medicine Deakin University Waurn Ponds Victoria Australia
- Walter and Eliza Hall Institute 1G Royal Parade Parkville Australia
| | - Thorey K. Jonsdottir
- Burnet Institute 85 Commercial Road Prahran Australia
- Department of Microbiology and Immunology University of Melbourne Parkville Australia
| | - David T. Riglar
- Walter and Eliza Hall Institute 1G Royal Parade Parkville Australia
- Department of Medical Biology University of Melbourne Parkville Australia
- Imperial College London Department of Infectious Diseases, South Kensington Campus, SW72AZ UK
| | - Oliver Looker
- Burnet Institute 85 Commercial Road Prahran Australia
| | - Catherine S. Palmer
- Burnet Institute 85 Commercial Road Prahran Australia
- Bio21, 30 Road Parkville Flemington Australia
| | | | - Sarah C. Charnaud
- Burnet Institute 85 Commercial Road Prahran Australia
- WHO Geneva Switzerland
| | - Tony Triglia
- Walter and Eliza Hall Institute 1G Royal Parade Parkville Australia
- Department of Medical Biology University of Melbourne Parkville Australia
| | - Mikha Gabriela
- Burnet Institute 85 Commercial Road Prahran Australia
- School of Medicine Deakin University Waurn Ponds Victoria Australia
- Walter and Eliza Hall Institute 1G Royal Parade Parkville Australia
| | | | - Jo‐Anne Chan
- Burnet Institute 85 Commercial Road Prahran Australia
- Department of Medicine University of Melbourne Parkville Victoria Australia
| | | | - Jake Baum
- Walter and Eliza Hall Institute 1G Royal Parade Parkville Australia
- Department of Medical Biology University of Melbourne Parkville Australia
- Imperial College London Department of Infectious Diseases, South Kensington Campus, SW72AZ UK
| | - James W. Kazura
- Centre for Global Health and Diseases Case Western Reserve University Cleveland Ohio USA
| | - James G. Beeson
- Burnet Institute 85 Commercial Road Prahran Australia
- Department of Medicine University of Melbourne Parkville Victoria Australia
- Department of Immunology, Central clinical school Monash University Melbourne Victoria Australia
| | - Alan F. Cowman
- Walter and Eliza Hall Institute 1G Royal Parade Parkville Australia
- Department of Medical Biology University of Melbourne Parkville Australia
| | - Paul R. Gilson
- Burnet Institute 85 Commercial Road Prahran Australia
- Department of Microbiology and Immunology University of Melbourne Parkville Australia
| | - Brendan S. Crabb
- Burnet Institute 85 Commercial Road Prahran Australia
- Department of Microbiology and Immunology University of Melbourne Parkville Australia
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21
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Molina-Franky J, Patarroyo ME, Kalkum M, Patarroyo MA. The Cellular and Molecular Interaction Between Erythrocytes and Plasmodium falciparum Merozoites. Front Cell Infect Microbiol 2022; 12:816574. [PMID: 35433504 PMCID: PMC9008539 DOI: 10.3389/fcimb.2022.816574] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 02/21/2022] [Indexed: 11/13/2022] Open
Abstract
Plasmodium falciparum is the most lethal human malaria parasite, partly due to its genetic variability and ability to use multiple invasion routes via its binding to host cell surface receptors. The parasite extensively modifies infected red blood cell architecture to promote its survival which leads to increased cell membrane rigidity, adhesiveness and permeability. Merozoites are initially released from infected hepatocytes and efficiently enter red blood cells in a well-orchestrated process that involves specific interactions between parasite ligands and erythrocyte receptors; symptoms of the disease occur during the life-cycle’s blood stage due to capillary blockage and massive erythrocyte lysis. Several studies have focused on elucidating molecular merozoite/erythrocyte interactions and host cell modifications; however, further in-depth analysis is required for understanding the parasite’s biology and thus provide the fundamental tools for developing prophylactic or therapeutic alternatives to mitigate or eliminate Plasmodium falciparum-related malaria. This review focuses on the cellular and molecular events during Plasmodium falciparum merozoite invasion of red blood cells and the alterations that occur in an erythrocyte once it has become infected.
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Affiliation(s)
- Jessica Molina-Franky
- Molecular Biology and Immunology Department, Fundación Instituto de Inmunología de Colombia (FIDIC), Bogotá, Colombia
- Department of Immunology and Theranostics, Arthur Riggs Diabetes and Metabolism Research Institute, Beckman Research Institute of the City of Hope, Duarte, CA, United States
- PhD Programme in Biotechnology, Universidad Nacional de Colombia, Bogotá, Colombia
| | - Manuel Elkin Patarroyo
- Molecular Biology and Immunology Department, Fundación Instituto de Inmunología de Colombia (FIDIC), Bogotá, Colombia
- Health Sciences Division, Universidad Santo Tomás, Bogotá, Colombia
- Faculty of Medicine, Universidad Nacional de Colombia, Bogotá, Colombia
| | - Markus Kalkum
- Department of Immunology and Theranostics, Arthur Riggs Diabetes and Metabolism Research Institute, Beckman Research Institute of the City of Hope, Duarte, CA, United States
- *Correspondence: Markus Kalkum, ; Manuel Alfonso Patarroyo,
| | - Manuel Alfonso Patarroyo
- Molecular Biology and Immunology Department, Fundación Instituto de Inmunología de Colombia (FIDIC), Bogotá, Colombia
- Health Sciences Division, Universidad Santo Tomás, Bogotá, Colombia
- Faculty of Medicine, Universidad Nacional de Colombia, Bogotá, Colombia
- *Correspondence: Markus Kalkum, ; Manuel Alfonso Patarroyo,
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22
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Shang X, Wang C, Shen L, Sheng F, He X, Wang F, Fan Y, He X, Jiang M. PfAP2-EXP2, an Essential Transcription Factor for the Intraerythrocytic Development of Plasmodium falciparum. Front Cell Dev Biol 2022; 9:782293. [PMID: 35083215 PMCID: PMC8785209 DOI: 10.3389/fcell.2021.782293] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Accepted: 12/09/2021] [Indexed: 12/13/2022] Open
Abstract
Plasmodium falciparum undergoes a series of asexual replications in human erythrocytes after infection, which are effective targets for combatting malaria. Here, we report roles of an ApiAP2 transcription factor PfAP2-EXP2 (PF3D7_0611200) in the intraerythrocytic developmental cycle of P. falciparum. PfAP2-EXP2 conditional knockdown resulted in an asexual growth defect but without an appreciable effect on parasite morphology. Further ChIP-seq analysis revealed that PfAP2-EXP2 targeted genes related to virulence and interaction between erythrocytes and parasites. Especially, PfAP2-EXP2 regulation of euchromatic genes does not depend on recognizing specific DNA sequences, while a CCCTAAACCC motif is found in its heterochromatic binding sites. Combined with transcriptome profiling, we suggest that PfAP2-EXP2 is participated in the intraerythrocytic development by affecting the expression of genes related to cell remodeling at the schizont stage. In summary, this study explores an ApiAP2 member plays an important role for the P. falciparum blood-stage replication, which suggests a new perspective for malaria elimination.
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Affiliation(s)
- Xiaomin Shang
- Department of Medical Genetics, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, China.,Department of Parasitology, Xiangya School of Medicine, Central South University, Changsha, China
| | - Changhong Wang
- Department of Medical Genetics, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Li Shen
- Department of Medical Genetics, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Fei Sheng
- Department of Medical Genetics, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Xiaohui He
- Department of Medical Genetics, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, China.,National Health Commission Key Laboratory of Parasitic Disease Control and Prevention, Jiangsu Provincial Key Laboratory on Parasite and Vector Control Technology, Jiangsu Institute of Parasitic Diseases, Wuxi, China
| | - Fei Wang
- Department of Medical Genetics, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Yanting Fan
- Department of Medical Genetics, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Xiaoqin He
- National Health Commission Key Laboratory of Parasitic Disease Control and Prevention, Jiangsu Provincial Key Laboratory on Parasite and Vector Control Technology, Jiangsu Institute of Parasitic Diseases, Wuxi, China
| | - Mei Jiang
- Department of Medical Genetics, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, China
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23
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Kreutzfeld O, Grützke J, Ingmundson A, Müller K, Matuschewski K. Absence of PEXEL-Dependent Protein Export in Plasmodium Liver Stages Cannot Be Restored by Gain of the HSP101 Protein Translocon ATPase. Front Genet 2021; 12:742153. [PMID: 34956312 PMCID: PMC8693896 DOI: 10.3389/fgene.2021.742153] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Accepted: 10/18/2021] [Indexed: 11/13/2022] Open
Abstract
Host cell remodeling is critical for successful Plasmodium replication inside erythrocytes and achieved by targeted export of parasite-encoded proteins. In contrast, during liver infection the malarial parasite appears to avoid protein export, perhaps to limit exposure of parasite antigens by infected liver cells. HSP101, the force-generating ATPase of the protein translocon of exported proteins (PTEX) is the only component that is switched off during early liver infection. Here, we generated transgenic Plasmodium berghei parasite lines that restore liver stage expression of HSP101. HSP101 expression in infected hepatocytes was achieved by swapping the endogenous promoter with the ptex150 promoter and by inserting an additional copy under the control of the elongation one alpha (ef1α) promoter. Both promoters drive constitutive and, hence, also pre-erythrocytic expression. Transgenic parasites were able to complete the life cycle, but failed to export PEXEL-proteins in early liver stages. Our results suggest that PTEX-dependent early liver stage export cannot be restored by addition of HSP101, indicative of alternative export complexes or other functions of the PTEX core complex during liver infection.
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Affiliation(s)
- Oriana Kreutzfeld
- Molecular Parasitology, Institute of Biology/Faculty for Life Sciences, Humboldt Universität zu Berlin, Berlin, Germany.,Parasitology Unit, Max Planck Institute for Infection Biology, Berlin, Germany.,Department of Medicine, University of California, San Francisco, San Francisco, CA, United States
| | - Josephine Grützke
- Molecular Parasitology, Institute of Biology/Faculty for Life Sciences, Humboldt Universität zu Berlin, Berlin, Germany.,Parasitology Unit, Max Planck Institute for Infection Biology, Berlin, Germany.,Department of Biological Safety, Federal Institute for Risk Assessment, Berlin, Germany
| | - Alyssa Ingmundson
- Molecular Parasitology, Institute of Biology/Faculty for Life Sciences, Humboldt Universität zu Berlin, Berlin, Germany.,Parasitology Unit, Max Planck Institute for Infection Biology, Berlin, Germany
| | - Katja Müller
- Molecular Parasitology, Institute of Biology/Faculty for Life Sciences, Humboldt Universität zu Berlin, Berlin, Germany.,Parasitology Unit, Max Planck Institute for Infection Biology, Berlin, Germany
| | - Kai Matuschewski
- Molecular Parasitology, Institute of Biology/Faculty for Life Sciences, Humboldt Universität zu Berlin, Berlin, Germany.,Parasitology Unit, Max Planck Institute for Infection Biology, Berlin, Germany
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24
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Band G, Leffler EM, Jallow M, Sisay-Joof F, Ndila CM, Macharia AW, Hubbart C, Jeffreys AE, Rowlands K, Nguyen T, Gonçalves S, Ariani CV, Stalker J, Pearson RD, Amato R, Drury E, Sirugo G, d'Alessandro U, Bojang KA, Marsh K, Peshu N, Saelens JW, Diakité M, Taylor SM, Conway DJ, Williams TN, Rockett KA, Kwiatkowski DP. Malaria protection due to sickle haemoglobin depends on parasite genotype. Nature 2021; 602:106-111. [PMID: 34883497 PMCID: PMC8810385 DOI: 10.1038/s41586-021-04288-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 11/29/2021] [Indexed: 11/30/2022]
Abstract
Host genetic factors can confer resistance against malaria1, raising the question of whether this has led to evolutionary adaptation of parasite populations. Here we searched for association between candidate host and parasite genetic variants in 3,346 Gambian and Kenyan children with severe malaria caused by Plasmodium falciparum. We identified a strong association between sickle haemoglobin (HbS) in the host and three regions of the parasite genome, which is not explained by population structure or other covariates, and which is replicated in additional samples. The HbS-associated alleles include nonsynonymous variants in the gene for the acyl-CoA synthetase family member2–4PfACS8 on chromosome 2, in a second region of chromosome 2, and in a region containing structural variation on chromosome 11. The alleles are in strong linkage disequilibrium and have frequencies that covary with the frequency of HbS across populations, in particular being much more common in Africa than other parts of the world. The estimated protective effect of HbS against severe malaria, as determined by comparison of cases with population controls, varies greatly according to the parasite genotype at these three loci. These findings open up a new avenue of enquiry into the biological and epidemiological significance of the HbS-associated polymorphisms in the parasite genome and the evolutionary forces that have led to their high frequency and strong linkage disequilibrium in African P. falciparum populations. A strong association has been found between three regions of the Plasmodium falciparum genome and sickle haemoglobin in children with severe malaria, suggesting parasites have adapted to overcome natural host immunity.
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Affiliation(s)
- Gavin Band
- Wellcome Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, UK. .,Wellcome Sanger Institute, Hinxton, Cambridge, UK. .,Big Data Institute, Li Ka Shing Centre for Health and Information Discovery, Old Road Campus, Oxford, USA.
| | - Ellen M Leffler
- Wellcome Sanger Institute, Hinxton, Cambridge, UK.,Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Muminatou Jallow
- Medical Research Council Unit The Gambia at the London School of Hygiene and Tropical Medicine, Atlantic Boulevard, Fajara, The Gambia.,Edward Francis Small Teaching Hospital (formerly Royal Victoria Teaching Hospital), Independence Drive, Banjul, The Gambia
| | - Fatoumatta Sisay-Joof
- Medical Research Council Unit The Gambia at the London School of Hygiene and Tropical Medicine, Atlantic Boulevard, Fajara, The Gambia
| | - Carolyne M Ndila
- KEMRI-Wellcome Trust Research Programme, PO Box 230, Kilifi, Kenya
| | | | - Christina Hubbart
- Wellcome Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, UK
| | - Anna E Jeffreys
- Wellcome Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, UK
| | - Kate Rowlands
- Wellcome Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, UK
| | - Thuy Nguyen
- Wellcome Sanger Institute, Hinxton, Cambridge, UK
| | | | | | - Jim Stalker
- Wellcome Sanger Institute, Hinxton, Cambridge, UK
| | - Richard D Pearson
- Wellcome Sanger Institute, Hinxton, Cambridge, UK.,Big Data Institute, Li Ka Shing Centre for Health and Information Discovery, Old Road Campus, Oxford, USA
| | | | | | - Giorgio Sirugo
- Medical Research Council Unit The Gambia at the London School of Hygiene and Tropical Medicine, Atlantic Boulevard, Fajara, The Gambia.,Division of Translational Medicine and Human Genetics, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
| | - Umberto d'Alessandro
- Medical Research Council Unit The Gambia at the London School of Hygiene and Tropical Medicine, Atlantic Boulevard, Fajara, The Gambia
| | - Kalifa A Bojang
- Medical Research Council Unit The Gambia at the London School of Hygiene and Tropical Medicine, Atlantic Boulevard, Fajara, The Gambia
| | - Kevin Marsh
- KEMRI-Wellcome Trust Research Programme, PO Box 230, Kilifi, Kenya.,Nuffield Department of Medicine, NDM Research Building, Roosevelt Drive, Headington, Oxford, UK
| | - Norbert Peshu
- KEMRI-Wellcome Trust Research Programme, PO Box 230, Kilifi, Kenya
| | - Joseph W Saelens
- Division of Infectious Diseases, Duke University School of Medicine, Durham, NC, USA
| | - Mahamadou Diakité
- Malaria Research and Training Center, University of Sciences, Techniques, and Technologies of Bamako, Bamako, Mali
| | - Steve M Taylor
- Division of Infectious Diseases, Duke University School of Medicine, Durham, NC, USA.,Duke Global Health Institute, Duke University, Durham, NC, USA
| | - David J Conway
- Medical Research Council Unit The Gambia at the London School of Hygiene and Tropical Medicine, Atlantic Boulevard, Fajara, The Gambia.,Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London, UK
| | - Thomas N Williams
- KEMRI-Wellcome Trust Research Programme, PO Box 230, Kilifi, Kenya.,Institute for Global Health Innovation, Department of Surgery and Cancer, Imperial College, London, London, UK
| | - Kirk A Rockett
- Wellcome Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, UK. .,Wellcome Sanger Institute, Hinxton, Cambridge, UK.
| | - Dominic P Kwiatkowski
- Wellcome Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, UK. .,Wellcome Sanger Institute, Hinxton, Cambridge, UK. .,Big Data Institute, Li Ka Shing Centre for Health and Information Discovery, Old Road Campus, Oxford, USA.
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25
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Goodswen SJ, Kennedy PJ, Ellis JT. Applying Machine Learning to Predict the Exportome of Bovine and Canine Babesia Species That Cause Babesiosis. Pathogens 2021; 10:660. [PMID: 34071992 PMCID: PMC8226867 DOI: 10.3390/pathogens10060660] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 05/24/2021] [Accepted: 05/25/2021] [Indexed: 01/08/2023] Open
Abstract
Babesia infection of red blood cells can cause a severe disease called babesiosis in susceptible hosts. Bovine babesiosis causes global economic loss to the beef and dairy cattle industries, and canine babesiosis is considered a clinically significant disease. Potential therapeutic targets against bovine and canine babesiosis include members of the exportome, i.e., those proteins exported from the parasite into the host red blood cell. We developed three machine learning-derived methods (two novel and one adapted) to predict for every known Babesia bovis, Babesia bigemina, and Babesia canis protein the probability of being an exportome member. Two well-studied apicomplexan-related species, Plasmodium falciparum and Toxoplasma gondii, with extensive experimental evidence on their exportome or excreted/secreted proteins were used as important benchmarks for the three methods. Based on 10-fold cross validation and multiple train-validation-test splits of training data, we expect that over 90% of the predicted probabilities accurately provide a secretory or non-secretory indicator. Only laboratory testing can verify that predicted high exportome membership probabilities are creditable exportome indicators. However, the presented methods at least provide those proteins most worthy of laboratory validation and will ultimately save time and money.
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Affiliation(s)
- Stephen J. Goodswen
- School of Life Sciences, University of Technology Sydney, 15 Broadway, Ultimo, NSW 2007, Australia;
| | - Paul J. Kennedy
- School of Computer Science, Faculty of Engineering and Information Technology, Australian Artificial Intelligence Institute, University of Technology Sydney, 15 Broadway, Ultimo, NSW 2007, Australia;
| | - John T. Ellis
- School of Life Sciences, University of Technology Sydney, 15 Broadway, Ultimo, NSW 2007, Australia;
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