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Zhang Z, Gaetjens TK, Ou J, Zhou Q, Yu Y, Mallory DP, Abel SM, Yu Y. Propulsive cell entry diverts pathogens from immune degradation by remodeling the phagocytic synapse. Proc Natl Acad Sci U S A 2023; 120:e2306788120. [PMID: 38032935 PMCID: PMC10710034 DOI: 10.1073/pnas.2306788120] [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: 05/01/2023] [Accepted: 10/05/2023] [Indexed: 12/02/2023] Open
Abstract
Phagocytosis is a critical immune function for infection control and tissue homeostasis. During phagocytosis, pathogens are internalized and degraded in phagolysosomes. For pathogens that evade immune degradation, the prevailing view is that virulence factors are required to disrupt the biogenesis of phagolysosomes. In contrast, we present here that physical forces from motile pathogens during cell entry divert them away from the canonical degradative pathway. This altered fate begins with the force-induced remodeling of the phagocytic synapse formation. We used the parasite Toxoplasma gondii as a model because live Toxoplasma actively invades host cells using gliding motility. To differentiate the effects of physical forces from virulence factors in phagocytosis, we employed magnetic forces to induce propulsive entry of inactivated Toxoplasma into macrophages. Experiments and computer simulations show that large propulsive forces hinder productive activation of receptors by preventing their spatial segregation from phosphatases at the phagocytic synapse. Consequently, the inactivated parasites are engulfed into vacuoles that fail to mature into degradative units, similar to the live motile parasite's intracellular pathway. Using yeast cells and opsonized beads, we confirmed that this mechanism is general, not specific to the parasite used. These results reveal new aspects of immune evasion by demonstrating how physical forces during active cell entry, independent of virulence factors, enable pathogens to circumvent phagolysosomal degradation.
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Affiliation(s)
- Zihan Zhang
- Department of Chemistry, Indiana University, Bloomington, IN47405-7102
| | - Thomas K. Gaetjens
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, TN37996
| | - Jin Ou
- Department of Chemistry, Indiana University, Bloomington, IN47405-7102
| | - Qiong Zhou
- Department of Chemistry, Indiana University, Bloomington, IN47405-7102
| | - Yanqi Yu
- Department of Chemistry, Indiana University, Bloomington, IN47405-7102
| | - D. Paul Mallory
- Department of Chemistry, Indiana University, Bloomington, IN47405-7102
| | - Steven M. Abel
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, TN37996
| | - Yan Yu
- Department of Chemistry, Indiana University, Bloomington, IN47405-7102
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2
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Zhang Z, Gaetjens TK, Yu Y, Paul Mallory D, Abel SM, Yu Y. Propulsive cell entry diverts pathogens from immune degradation by remodeling the phagocytic synapse. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.25.538287. [PMID: 37162866 PMCID: PMC10168248 DOI: 10.1101/2023.04.25.538287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Phagocytosis is a critical immune function for infection control and tissue homeostasis. This process is typically described as non-moving pathogens being internalized and degraded in phagolysosomes. For pathogens that evade immune degradation, the prevailing view is that virulence factors that biochemically disrupt the biogenesis of phagoslysosomes are required. In contrast, here we report that physical forces exerted by pathogens during cell entry divert them away from the canonical phagolysosomal degradation pathway, and this altered intracellular fate is determined at the time of phagocytic synapse formation. We used the eukaryotic parasite Toxoplasma gondii as a model because live Toxoplasma uses gliding motility to actively invade into host cells. To differentiate the effect of physical forces from that of virulence factors in phagocytosis, we developed a strategy that used magnetic forces to induce propulsive entry of inactivated Toxoplasma into macrophage cells. Experiments and computer simulations collectively reveal that large propulsive forces suppress productive activation of receptors by hindering their spatial segregation from phosphatases at the phagocytic synapse. Consequently, the inactivated parasites, instead of being degraded in phagolysosomes, are engulfed into vacuoles that fail to mature into degradative units, following an intracellular pathway strikingly similar to that of the live motile parasite. Using opsonized beads, we further confirmed that this mechanism is general, not specific to the parasite used. These results reveal previously unknown aspects of immune evasion by demonstrating how physical forces exerted during active cell entry, independent of virulence factors, can help pathogens circumvent phagolysosomal degradation.
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Affiliation(s)
- Zihan Zhang
- Department of Chemistry, Indiana University, Bloomington, IN 47405-7102
| | - Thomas K. Gaetjens
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, TN 37996
| | - Yanqi Yu
- Department of Chemistry, Indiana University, Bloomington, IN 47405-7102
| | - D. Paul Mallory
- Department of Chemistry, Indiana University, Bloomington, IN 47405-7102
| | - Steven M. Abel
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, TN 37996
| | - Yan Yu
- Department of Chemistry, Indiana University, Bloomington, IN 47405-7102
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3
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Structure and function of an atypical homodimeric actin capping protein from the malaria parasite. Cell Mol Life Sci 2022; 79:125. [PMID: 35132495 PMCID: PMC8821504 DOI: 10.1007/s00018-021-04032-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 10/28/2021] [Accepted: 11/09/2021] [Indexed: 11/27/2022]
Abstract
Apicomplexan parasites, such as Plasmodium spp., rely on an unusual actomyosin motor, termed glideosome, for motility and host cell invasion. The actin filaments are maintained by a small set of essential regulators, which provide control over actin dynamics in the different stages of the parasite life cycle. Actin filament capping proteins (CPs) are indispensable heterodimeric regulators of actin dynamics. CPs have been extensively characterized in higher eukaryotes, but their role and functional mechanism in Apicomplexa remain enigmatic. Here, we present the first crystal structure of a homodimeric CP from the malaria parasite and compare the homo- and heterodimeric CP structures in detail. Despite retaining several characteristics of a canonical CP, the homodimeric Plasmodium berghei (Pb)CP exhibits crucial differences to the canonical heterodimers. Both homo- and heterodimeric PbCPs regulate actin dynamics in an atypical manner, facilitating rapid turnover of parasite actin, without affecting its critical concentration. Homo- and heterodimeric PbCPs show partially redundant activities, possibly to rescue actin filament capping in life cycle stages where the β-subunit is downregulated. Our data suggest that the homodimeric PbCP also influences actin kinetics by recruiting lateral actin dimers. This unusual function could arise from the absence of a β-subunit, as the asymmetric PbCP homodimer lacks structural elements essential for canonical barbed end interactions suggesting a novel CP binding mode. These findings will facilitate further studies aimed at elucidating the precise actin filament capping mechanism in Plasmodium.
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Frasse PM, Miller JJ, Polino AJ, Soleimani E, Zhu JS, Jakeman DL, Jez JM, Goldberg DE, Odom John AR. Enzymatic and structural characterization of HAD5, an essential phosphomannomutase of malaria-causing parasites. J Biol Chem 2022; 298:101550. [PMID: 34973333 PMCID: PMC8808168 DOI: 10.1016/j.jbc.2021.101550] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2021] [Revised: 12/22/2021] [Accepted: 12/23/2021] [Indexed: 11/05/2022] Open
Abstract
The malaria-causing parasite Plasmodium falciparum is responsible for over 200 million infections and 400,000 deaths per year. At multiple stages during its complex life cycle, P. falciparum expresses several essential proteins tethered to its surface by glycosylphosphatidylinositol (GPI) anchors, which are critical for biological processes such as parasite egress and reinvasion of host red blood cells. Targeting this pathway therapeutically has the potential to broadly impact parasite development across several life stages. Here, we characterize an upstream component of parasite GPI anchor biosynthesis, the putative phosphomannomutase (PMM) (EC 5.4.2.8), HAD5 (PF3D7_1017400). We confirmed the PMM and phosphoglucomutase activities of purified recombinant HAD5 by developing novel linked enzyme biochemical assays. By regulating the expression of HAD5 in transgenic parasites with a TetR-DOZI-inducible knockdown system, we demonstrated that HAD5 is required for malaria parasite egress and erythrocyte reinvasion, and we assessed the role of HAD5 in GPI anchor synthesis by autoradiography of radiolabeled glucosamine and thin layer chromatography. Finally, we determined the three-dimensional X-ray crystal structure of HAD5 and identified a substrate analog that specifically inhibits HAD5 compared to orthologous human PMMs in a time-dependent manner. These findings demonstrate that the GPI anchor biosynthesis pathway is exceptionally sensitive to inhibition in parasites and that HAD5 has potential as a specific, multistage antimalarial target.
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Affiliation(s)
- Philip M Frasse
- Division of Infectious Diseases, Departments of Medicine and Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Justin J Miller
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Alexander J Polino
- Division of Infectious Diseases, Departments of Medicine and Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Ebrahim Soleimani
- College of Pharmacy, Dalhousie University, Halifax, Nova Scotia, Canada; Department of Chemistry, Razi University, Kermanshah, Iran
| | - Jian-She Zhu
- College of Pharmacy, Dalhousie University, Halifax, Nova Scotia, Canada
| | - David L Jakeman
- College of Pharmacy, Dalhousie University, Halifax, Nova Scotia, Canada; Department of Chemistry, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Joseph M Jez
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Daniel E Goldberg
- Division of Infectious Diseases, Departments of Medicine and Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Audrey R Odom John
- Division of Infectious Diseases, Department of Pediatrics, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
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5
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Curcumin reduces enteric isoprostane 8-iso-PGF2α and prostaglandin GF2α in specific pathogen-free Leghorn chickens challenged with Eimeria maxima. Sci Rep 2021; 11:11609. [PMID: 34078952 PMCID: PMC8172875 DOI: 10.1038/s41598-021-90679-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Accepted: 05/10/2021] [Indexed: 12/12/2022] Open
Abstract
The purpose of this pilot study was to evaluate and determine the concentration of prostaglandin GF2α (PGF2α) and isoprostane 8‐iso‐PGF2α in plasma and intestine of specific pathogen-free (SPF) Leghorn chickens challenged with Eimeria maxima, with or without dietary supplementation of curcumin using solid‐phase microextraction and ultra‐performance liquid chromatography/tandem mass spectrometry. Eighty 1-day-old male SPF chickens were randomly allocated to one of four groups with four replicates (n = 5 chickens/replicate). Groups consisted of: (1) Control (no challenge), (2) Curcumin (no challenge), (3) Eimeria maxima (challenge), and (4) Eimeria maxima (challenge) + curcumin. At day 28 of age, all chickens in the challenge groups were orally gavaged with 40,000 sporulated E. maxima oocysts. No significant differences (P > 0.05) were observed in the groups regardless of the treatment or challenge with E. maxima. Enteric levels of both isoprostane 8‐iso‐PGF2α and PGF2α at 7 days and 9 days post-challenge were significantly increased (P < 0.01) compared to the non-challenge control chickens. Interestingly, the enteric levels of both isoprostane 8‐iso‐PGF2α and PGF2α at 7 days post-challenge were significantly reduced in chickens fed curcumin, compared to control chickens challenge with E. maxima. At 9 days post-challenge, only levels of isoprostane 8‐iso‐PGF2α in the enteric samples were significantly reduced in chickens challenged with E. maxima supplemented with curcumin, compared with E. maxima challenge chickens. No differences of isoprostane 8‐iso‐PGF2α or PGF2α were observed in plasma at both days of evaluation. Similarly, no significant differences were observed between the challenge control or chickens challenge with E. maxima and supplemented with curcumin at both times of evaluation. The results of this pilot study suggests that the antioxidant anti-inflammatory properties of curcumin reduced the oxidative damage and subsequent intestinal mucosal over-production of lipid oxidation products. Further studies to confirm and extend these results in broiler chickens are required.
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Wichers JS, Wunderlich J, Heincke D, Pazicky S, Strauss J, Schmitt M, Kimmel J, Wilcke L, Scharf S, von Thien H, Burda PC, Spielmann T, Löw C, Filarsky M, Bachmann A, Gilberger TW. Identification of novel inner membrane complex and apical annuli proteins of the malaria parasite Plasmodium falciparum. Cell Microbiol 2021; 23:e13341. [PMID: 33830607 DOI: 10.1111/cmi.13341] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 03/29/2021] [Accepted: 04/05/2021] [Indexed: 02/06/2023]
Abstract
The inner membrane complex (IMC) is a defining feature of apicomplexan parasites, which confers stability and shape to the cell, functions as a scaffolding compartment during the formation of daughter cells and plays an important role in motility and invasion during different life cycle stages of these single-celled organisms. To explore the IMC proteome of the malaria parasite Plasmodium falciparum we applied a proximity-dependent biotin identification (BioID)-based proteomics approach, using the established IMC marker protein Photosensitized INA-Labelled protein 1 (PhIL1) as bait in asexual blood-stage parasites. Subsequent mass spectrometry-based peptide identification revealed enrichment of 12 known IMC proteins and several uncharacterized candidate proteins. We validated nine of these previously uncharacterized proteins by endogenous GFP-tagging. Six of these represent new IMC proteins, while three proteins have a distinct apical localization that most likely represents structures described as apical annuli in Toxoplasma gondii. Additionally, various Kelch13 interacting candidates were identified, suggesting an association of the Kelch13 compartment and the IMC in schizont and merozoite stages. This work extends the number of validated IMC proteins in the malaria parasite and reveals for the first time the existence of apical annuli proteins in P. falciparum. Additionally, it provides evidence for a spatial association between the Kelch13 compartment and the IMC in late blood-stage parasites.
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Affiliation(s)
- Jan Stephan Wichers
- Centre for Structural Systems Biology, Hamburg, Germany.,Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany.,University of Hamburg, Hamburg, Germany
| | - Juliane Wunderlich
- Centre for Structural Systems Biology, Hamburg, Germany.,European Molecular Biology Laboratory, Hamburg Unit, Hamburg, Germany
| | - Dorothee Heincke
- Centre for Structural Systems Biology, Hamburg, Germany.,Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany.,University of Hamburg, Hamburg, Germany
| | - Samuel Pazicky
- Centre for Structural Systems Biology, Hamburg, Germany.,European Molecular Biology Laboratory, Hamburg Unit, Hamburg, Germany
| | - Jan Strauss
- Centre for Structural Systems Biology, Hamburg, Germany.,Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany.,University of Hamburg, Hamburg, Germany
| | - Marius Schmitt
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Jessica Kimmel
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Louisa Wilcke
- Centre for Structural Systems Biology, Hamburg, Germany.,Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany.,University of Hamburg, Hamburg, Germany
| | - Sarah Scharf
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Heidrun von Thien
- 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
| | - Tobias Spielmann
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Christian Löw
- Centre for Structural Systems Biology, Hamburg, Germany.,European Molecular Biology Laboratory, Hamburg Unit, Hamburg, Germany
| | - Michael Filarsky
- Centre for Structural Systems Biology, Hamburg, Germany.,University of Hamburg, Hamburg, Germany
| | - Anna Bachmann
- Centre for Structural Systems Biology, Hamburg, Germany.,Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany.,University of Hamburg, Hamburg, Germany.,German Centre for Infection Research (DZIF), partner site Hamburg-Borstel-Lübeck-Riems, Braunschweig, Germany
| | - Tim W Gilberger
- Centre for Structural Systems Biology, Hamburg, Germany.,Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany.,University of Hamburg, Hamburg, Germany
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Das S, Stortz JF, Meissner M, Periz J. The multiple functions of actin in apicomplexan parasites. Cell Microbiol 2021; 23:e13345. [PMID: 33885206 DOI: 10.1111/cmi.13345] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 03/30/2021] [Accepted: 03/31/2021] [Indexed: 11/29/2022]
Abstract
The cytoskeletal protein actin is highly abundant and conserved in eukaryotic cells. It occurs in two different states- the globular (G-actin) form, which can polymerise into the filamentous (F-actin) form, fulfilling various critical functions including cytokinesis, cargo trafficking and cellular motility. In higher eukaryotes, there are several actin isoforms with nearly identical amino acid sequences. Despite the high level of amino acid identity, they display regulated expression patterns and unique non-redundant roles. The number of actin isoforms together with conserved sequences may reflect the selective pressure exerted by scores of actin binding proteins (ABPs) in higher eukaryotes. In contrast, in many protozoans such as apicomplexan parasites which possess only a few ABPs, the regulatory control of actin and its multiple functions are still obscure. Here, we provide a summary of the regulation and biological functions of actin in higher eukaryotes and compare it with the current knowledge in apicomplexans. We discuss future experiments that will help us understand the multiple, critical roles of this fascinating system in apicomplexans.
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Affiliation(s)
- Sujaan Das
- Faculty of Veterinary Medicine, Experimental Parasitology, Ludwig Maximilian University, Munich, Germany
| | - Johannes Felix Stortz
- Department Metabolism of Infection, Max Planck Institute for Biology of Ageing, Cologne, Germany
| | - Markus Meissner
- Faculty of Veterinary Medicine, Experimental Parasitology, Ludwig Maximilian University, Munich, Germany
| | - Javier Periz
- Faculty of Veterinary Medicine, Experimental Parasitology, Ludwig Maximilian University, Munich, Germany
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Phosphorylation of Rhoptry Protein RhopH3 Is Critical for Host Cell Invasion by the Malaria Parasite. mBio 2020; 11:mBio.00166-20. [PMID: 33024030 PMCID: PMC7542355 DOI: 10.1128/mbio.00166-20] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Host cell invasion by the malaria parasite is critical for establishing infection in human host and is dependent on discharge of key ligands from organelles like rhoptry and microneme, and these ligands interact with host RBC receptors. In the present study, we demonstrate that phosphorylation of a key rhoptry protein, RhopH3, is critical for host invasion. Phosphorylation regulates its localization to rhoptries and discharge from the parasite. Merozoites formed after asexual division of the malaria parasite invade the host red blood cells (RBCs), which is critical for initiating malaria infection. The process of invasion involves specialized organelles like micronemes and rhoptries that discharge key proteins involved in interaction with host RBC receptors. RhopH complex comprises at least three proteins, which include RhopH3. RhopH3 is critical for the process of red blood cell (RBC) invasion as well as intraerythrocytic development of human malaria parasite Plasmodium falciparum. It is phosphorylated at serine 804 (S804) in the parasite; however, it is unclear if phosphorylation regulates its function. To address this, a CRISPR-CAS9-based approach was used to mutate S804 to alanine (A) in P. falciparum. Using this phosphomutant (R3_S804A) of RhopH3, we demonstrate that the phosphorylation of S804 is critical for host RBC invasion by the parasite but not for its intraerythrocytic development. Importantly, the phosphorylation of RhopH3 regulates its localization to the rhoptries and discharge from the parasite, which is critical for RBC invasion. We also identified P. falciparum CDPK1 (PfCDPK1) as a possible candidate kinase for RhopH3-S804 phosphorylation and found that it regulates RhopH3 secretion from the parasite. These findings provide novel insights into the role of phosphorylation in rhoptry release and invasion, which is poorly understood.
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9
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Polyphyletic origin, intracellular invasion, and meiotic genes in the putatively asexual agamococcidians (Apicomplexa incertae sedis). Sci Rep 2020; 10:15847. [PMID: 32985520 PMCID: PMC7522995 DOI: 10.1038/s41598-020-72287-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 08/28/2020] [Indexed: 12/30/2022] Open
Abstract
Agamococcidians are enigmatic and poorly studied parasites of marine invertebrates with unexplored diversity and unclear relationships to other sporozoans such as the human pathogens Plasmodium and Toxoplasma. It is believed that agamococcidians are not capable of sexual reproduction, which is essential for life cycle completion in all well studied parasitic apicomplexans. Here, we describe three new species of agamococcidians belonging to the genus Rhytidocystis. We examined their cell morphology and ultrastructure, resolved their phylogenetic position by using near-complete rRNA operon sequences, and searched for genes associated with meiosis and oocyst wall formation in two rhytidocystid transcriptomes. Phylogenetic analyses consistently recovered rhytidocystids as basal coccidiomorphs and away from the corallicolids, demonstrating that the order Agamococcidiorida Levine, 1979 is polyphyletic. Light and transmission electron microscopy revealed that the development of rhytidocystids begins inside the gut epithelial cells, a characteristic which links them specifically with other coccidiomorphs to the exclusion of gregarines and suggests that intracellular invasion evolved early in the coccidiomorphs. We propose a new superorder Eococcidia for early coccidiomorphs. Transcriptomic analysis demonstrated that both the meiotic machinery and oocyst wall proteins are preserved in rhytidocystids. The conservation of meiotic genes and ultrastructural similarity of rhytidocystid trophozoites to macrogamonts of true coccidians point to an undescribed, cryptic sexual process in the group.
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Nadipuram SM, Thind AC, Rayatpisheh S, Wohlschlegel JA, Bradley PJ. Proximity biotinylation reveals novel secreted dense granule proteins of Toxoplasma gondii bradyzoites. PLoS One 2020; 15:e0232552. [PMID: 32374791 PMCID: PMC7202600 DOI: 10.1371/journal.pone.0232552] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Accepted: 04/16/2020] [Indexed: 02/06/2023] Open
Abstract
Toxoplasma gondii is an obligate intracellular parasite which is capable of establishing life-long chronic infection in any mammalian host. During the intracellular life cycle, the parasite secretes an array of proteins into the parasitophorous vacuole (PV) where it resides. Specialized organelles called the dense granules secrete GRA proteins that are known to participate in nutrient acquisition, immune evasion, and host cell-cycle manipulation. Although many GRAs have been discovered which are expressed during the acute infection mediated by tachyzoites, little is known about those that participate in the chronic infection mediated by the bradyzoite form of the parasite. In this study, we sought to uncover novel bradyzoite-upregulated GRA proteins using proximity biotinylation, which we previously used to examine the secreted proteome of the tachyzoites. Using a fusion of the bradyzoite upregulated protein MAG1 to BirA* as bait and a strain with improved switch efficiency, we identified a number of novel GRA proteins which are expressed in bradyzoites. After using the CRISPR/Cas9 system to characterize these proteins by gene knockout, we focused on one of these GRAs (GRA55) and found it was important for the establishment or maintenance of cysts in the mouse brain. These findings highlight new components of the GRA proteome of the tissue-cyst life stage of T. gondii and identify potential targets that are important for maintenance of parasite persistence in vivo.
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Affiliation(s)
- Santhosh Mukund Nadipuram
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, California, United States of America
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Cedar-Sinai Medical Center, Los Angeles, California, United States of America
| | - Amara Cervantes Thind
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, California, United States of America
- Molecular Biology Institute, University of California, Los Angeles, California, United States of America
| | - Shima Rayatpisheh
- Department of Biological Chemistry and Institute of Genomics and Proteomics, University of California, Los Angeles, California, United States of America
| | - James Akira Wohlschlegel
- Molecular Biology Institute, University of California, Los Angeles, California, United States of America
- Department of Biological Chemistry and Institute of Genomics and Proteomics, University of California, Los Angeles, California, United States of America
| | - Peter John Bradley
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, California, United States of America
- Molecular Biology Institute, University of California, Los Angeles, California, United States of America
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11
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Amlabu E, Ilani P, Opoku G, Nyarko PB, Quansah E, Thiam LG, Anim M, Ayivor-Djanie R, Akuh OA, Mensah-Brown H, Rayner JC, Awandare GA. Molecular Characterization and Immuno-Reactivity Patterns of a Novel Plasmodium falciparum Armadillo-Type Repeat Protein, PfATRP. Front Cell Infect Microbiol 2020; 10:114. [PMID: 32266165 PMCID: PMC7100384 DOI: 10.3389/fcimb.2020.00114] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Accepted: 03/02/2020] [Indexed: 01/30/2023] Open
Abstract
Nearly half of the genes in the Plasmodium falciparum genome have not yet been functionally investigated. We used homology-based structural modeling to identify multiple copies of Armadillo repeats within one uncharacterized gene expressed during the intraerythrocytic stages, PF3D7_0410600, subsequently referred to as P. falciparum Armadillo-Type Repeat Protein (PfATRP). Soluble recombinant PfATRP was expressed in a bacterial expression system, purified to apparent homogeneity and the identity of the recombinant PfATRP was confirmed by mass spectrometry. Affinity-purified α-PfATRP rabbit antibodies specifically recognized the recombinant protein. Immunofluorescence assays revealed that α-PfATRP rabbit antibodies reacted with P. falciparum schizonts. Anti-PfATRP antibody exhibited peripheral staining patterns around the merozoites. Given the localization of PfATRP in merozoites, we tested for an egress phenotype during schizont arrest assays and demonstrated that native PfATRP is inaccessible on the surface of merozoites in intact schizonts. Dual immunofluorescence assays with markers for the inner membrane complex (IMC) and microtubules suggest partial colocalization in both asexual and sexual stage parasites. Using the soluble recombinant PfATRP in a screen of plasma samples revealed that malaria-infected children have naturally acquired PfATRP-specific antibodies.
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Affiliation(s)
- Emmanuel Amlabu
- West African Center for Cell Biology of Infectious Pathogens, University of Ghana, Accra, Ghana
- Department of Biochemistry, Kogi State University, Anyigba, Nigeria
| | - Philip Ilani
- West African Center for Cell Biology of Infectious Pathogens, University of Ghana, Accra, Ghana
| | - Grace Opoku
- West African Center for Cell Biology of Infectious Pathogens, University of Ghana, Accra, Ghana
| | - Prince B. Nyarko
- West African Center for Cell Biology of Infectious Pathogens, University of Ghana, Accra, Ghana
| | - Evelyn Quansah
- West African Center for Cell Biology of Infectious Pathogens, University of Ghana, Accra, Ghana
| | - Laty G. Thiam
- West African Center for Cell Biology of Infectious Pathogens, University of Ghana, Accra, Ghana
| | - Manfred Anim
- West African Center for Cell Biology of Infectious Pathogens, University of Ghana, Accra, Ghana
| | - Reuben Ayivor-Djanie
- West African Center for Cell Biology of Infectious Pathogens, University of Ghana, Accra, Ghana
- Department of Biomedical Sciences, SBBS, University of Health and Allied Sciences, Ho, Ghana
| | - Ojo-ajogu Akuh
- West African Center for Cell Biology of Infectious Pathogens, University of Ghana, Accra, Ghana
| | - Henrietta Mensah-Brown
- West African Center for Cell Biology of Infectious Pathogens, University of Ghana, Accra, Ghana
| | - Julian C. Rayner
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
| | - Gordon A. Awandare
- West African Center for Cell Biology of Infectious Pathogens, University of Ghana, Accra, Ghana
- Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, Accra, Ghana
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12
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Burns AL, Dans MG, Balbin JM, de Koning-Ward TF, Gilson PR, Beeson JG, Boyle MJ, Wilson DW. Targeting malaria parasite invasion of red blood cells as an antimalarial strategy. FEMS Microbiol Rev 2019; 43:223-238. [PMID: 30753425 PMCID: PMC6524681 DOI: 10.1093/femsre/fuz005] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2018] [Accepted: 02/11/2019] [Indexed: 12/20/2022] Open
Abstract
Plasmodium spp. parasites that cause malaria disease remain a significant global-health burden. With the spread of parasites resistant to artemisinin combination therapies in Southeast Asia, there is a growing need to develop new antimalarials with novel targets. Invasion of the red blood cell by Plasmodium merozoites is essential for parasite survival and proliferation, thus representing an attractive target for therapeutic development. Red blood cell invasion requires a co-ordinated series of protein/protein interactions, protease cleavage events, intracellular signals, organelle release and engagement of an actin-myosin motor, which provide many potential targets for drug development. As these steps occur in the bloodstream, they are directly susceptible and exposed to drugs. A number of invasion inhibitors against a diverse range of parasite proteins involved in these different processes of invasion have been identified, with several showing potential to be optimised for improved drug-like properties. In this review, we discuss red blood cell invasion as a drug target and highlight a number of approaches for developing antimalarials with invasion inhibitory activity to use in future combination therapies.
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Affiliation(s)
- Amy L Burns
- Research Centre for Infectious Diseases, School of Biological Sciences, University of Adelaide, Adelaide, Australia 5005
| | - Madeline G Dans
- Burnet Institute, Melbourne, Victoria, Australia 3004.,Deakin University, School of Medicine, Waurn Ponds, Victoria, Australia 3216
| | - Juan M Balbin
- Research Centre for Infectious Diseases, School of Biological Sciences, University of Adelaide, Adelaide, Australia 5005
| | | | - Paul R Gilson
- Burnet Institute, Melbourne, Victoria, Australia 3004
| | - James G Beeson
- Burnet Institute, Melbourne, Victoria, Australia 3004.,Central Clinical School and Department of Microbiology, Monash University 3004.,Department of Medicine, University of Melbourne, Australia 3052
| | - Michelle J Boyle
- Burnet Institute, Melbourne, Victoria, Australia 3004.,QIMR Berghofer Medical Research Institute, Herston, Queensland, Australia 4006
| | - Danny W Wilson
- Research Centre for Infectious Diseases, School of Biological Sciences, University of Adelaide, Adelaide, Australia 5005.,Burnet Institute, Melbourne, Victoria, Australia 3004
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Stortz JF, Del Rosario M, Singer M, Wilkes JM, Meissner M, Das S. Formin-2 drives polymerisation of actin filaments enabling segregation of apicoplasts and cytokinesis in Plasmodium falciparum. eLife 2019; 8:e49030. [PMID: 31322501 PMCID: PMC6688858 DOI: 10.7554/elife.49030] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Accepted: 07/17/2019] [Indexed: 12/16/2022] Open
Abstract
In addition to its role in erythrocyte invasion, Plasmodium falciparum actin is implicated in endocytosis, cytokinesis and inheritance of the chloroplast-like organelle called the apicoplast. Previously, the inability to visualise filamentous actin (F-actin) dynamics had restricted the characterisation of both F-actin and actin regulatory proteins, a limitation we recently overcame for Toxoplasma (Periz et al, 2017). Here, we have expressed and validated actin-binding chromobodies as F-actin-sensors in Plasmodium falciparum and characterised in-vivo actin dynamics. F-actin could be chemically modulated, and genetically disrupted upon conditionally deleting actin-1. In a comparative approach, we demonstrate that Formin-2, a predicted nucleator of F-actin, is responsible for apicoplast inheritance in both Plasmodium and Toxoplasma, and additionally mediates efficient cytokinesis in Plasmodium. Finally, time-averaged local intensity measurements of F-actin in Toxoplasma conditional mutants revealed molecular determinants of spatiotemporally regulated F-actin flow. Together, our data indicate that Formin-2 is the primary F-actin nucleator during apicomplexan intracellular growth, mediating multiple essential functions.
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Affiliation(s)
- Johannes Felix Stortz
- Wellcome Centre for Integrative Parasitology, Institute of Infection, Immunity & InflammationUniversity of GlasgowGlasgowUnited Kingdom
| | - Mario Del Rosario
- Wellcome Centre for Integrative Parasitology, Institute of Infection, Immunity & InflammationUniversity of GlasgowGlasgowUnited Kingdom
| | - Mirko Singer
- Faculty of Veterinary Medicine, Experimental ParasitologyLudwig Maximilian UniversityMunichGermany
| | - Jonathan M Wilkes
- Wellcome Centre for Integrative Parasitology, Institute of Infection, Immunity & InflammationUniversity of GlasgowGlasgowUnited Kingdom
| | - Markus Meissner
- Wellcome Centre for Integrative Parasitology, Institute of Infection, Immunity & InflammationUniversity of GlasgowGlasgowUnited Kingdom
- Faculty of Veterinary Medicine, Experimental ParasitologyLudwig Maximilian UniversityMunichGermany
| | - Sujaan Das
- Wellcome Centre for Integrative Parasitology, Institute of Infection, Immunity & InflammationUniversity of GlasgowGlasgowUnited Kingdom
- Faculty of Veterinary Medicine, Experimental ParasitologyLudwig Maximilian UniversityMunichGermany
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Motility and cytoskeletal organisation in the archigregarine Selenidium pygospionis (Apicomplexa): observations on native and experimentally affected parasites. Parasitol Res 2019; 118:2651-2667. [PMID: 31270680 DOI: 10.1007/s00436-019-06381-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2019] [Accepted: 06/19/2019] [Indexed: 10/26/2022]
Abstract
Representatives of Apicomplexa perform various kinds of movements that are linked to the different stages of their life cycle. Ancestral apicomplexan lineages, including gregarines, represent organisms suitable for research into the evolution and diversification of motility within the group. The vermiform trophozoites and gamonts of the archigregarine Selenidium pygospionis perform a very active type of bending motility. Experimental assays and subsequent light, electron, and confocal microscopic analyses demonstrated the fundamental role of the cytoskeletal proteins actin and tubulin in S. pygospionis motility and allowed us to compare the mechanism of its movement to the gliding machinery (the so-called glideosome concept) described in apicomplexan zoites. Actin-modifying drugs caused a reduction in the movement speed (cytochalasin D) or stopped the motility of archigregarines completely (jasplakinolide). Microtubule-disrupting drugs (oryzalin and colchicine) had an even more noticeable effect on archigregarine motility. The fading and disappearance of microtubules were documented in ultrathin sections, along with the formation of α-tubulin clusters visible after the immunofluorescent labelling of drug-treated archigregarines. The obtained data indicate that subpellicular microtubules most likely constitute the main motor structure involved in S. pygospionis bending motility, while actin has rather a supportive function.
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Jalovecka M, Sojka D, Ascencio M, Schnittger L. Babesia Life Cycle - When Phylogeny Meets Biology. Trends Parasitol 2019; 35:356-368. [PMID: 30733093 DOI: 10.1016/j.pt.2019.01.007] [Citation(s) in RCA: 99] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Revised: 01/11/2019] [Accepted: 01/14/2019] [Indexed: 10/27/2022]
Abstract
Although Babesia represents an important worldwide veterinary threat and an emerging risk to humans, this parasite has been poorly studied as compared to Plasmodium, its malaria-causing relative. In fact, Babesia employs highly specific survival strategies during its intraerythrocytic development and its intricate journey through the tick vector. This review introduces a substantially extended molecular phylogeny of the order Piroplasmida, challenging previous taxonomic classifications. The intriguing developmental proficiencies of Babesia are highlighted and compared with those of other haemoparasitic Apicomplexa. Molecular mechanisms associated with distinctive events in the Babesia life cycle are emphasized as potential targets for the development of Babesia-specific treatments.
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Affiliation(s)
- Marie Jalovecka
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, CZ-370 05 Ceske Budejovice, Czech Republic; Faculty of Science, University of South Bohemia, CZ-370 05 Ceske Budejovice, Czech Republic.
| | - Daniel Sojka
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, CZ-370 05 Ceske Budejovice, Czech Republic
| | - Mariano Ascencio
- Instituto de Patobiología Veterinaria, Centro de Investigaciones en Ciencias Veterinarias y Agronómicas (CICVyA), INTA-Castelar, Los Reseros y Nicolas Repetto s/n, Hurlingham 1686, Argentina; National Council of Scientific and Technological Research (CONICET), Ciudad Autónoma de Buenos Aires C1033AAJ, Argentina
| | - Leonhard Schnittger
- Instituto de Patobiología Veterinaria, Centro de Investigaciones en Ciencias Veterinarias y Agronómicas (CICVyA), INTA-Castelar, Los Reseros y Nicolas Repetto s/n, Hurlingham 1686, Argentina; National Council of Scientific and Technological Research (CONICET), Ciudad Autónoma de Buenos Aires C1033AAJ, Argentina
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16
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Suarez CE, Alzan HF, Silva MG, Rathinasamy V, Poole WA, Cooke BM. Unravelling the cellular and molecular pathogenesis of bovine babesiosis: is the sky the limit? Int J Parasitol 2019; 49:183-197. [PMID: 30690089 PMCID: PMC6988112 DOI: 10.1016/j.ijpara.2018.11.002] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Revised: 11/21/2018] [Accepted: 11/21/2018] [Indexed: 11/21/2022]
Abstract
The global impact of bovine babesiosis caused by the tick-borne apicomplexan parasites Babesia bovis, Babesia bigemina and Babesia divergens is vastly underappreciated. These parasites invade and multiply asexually in bovine red blood cells (RBCs), undergo sexual reproduction in their tick vectors (Rhipicephalus spp. for B. bovis and B. bigemina, and Ixodes ricinus for B. divergens) and have a trans-ovarial mode of transmission. Babesia parasites can cause acute and persistent infections to adult naïve cattle that can occur without evident clinical signs, but infections caused by B. bovis are associated with more severe disease and increased mortality, and are considered to be the most virulent agent of bovine babesiosis. In addition, babesiosis caused by B. divergens has an important zoonotic potential. The disease caused by B. bovis and B. bigemina can be controlled, at least in part, using therapeutic agents or vaccines comprising live-attenuated parasites, but these methods are limited in terms of their safety, ease of deployability and long-term efficacy, and improved control measures are urgently needed. In addition, expansion of tick habitats due to climate change and other rapidly changing environmental factors complicate efficient control of these parasites. While the ability to cause persistent infections facilitates transmission and persistence of the parasite in endemic regions, it also highlights their capacity to evade the host immune responses. Currently, the mechanisms of immune responses used by infected bovines to survive acute and chronic infections remain poorly understood, warranting further research. Similarly, molecular details on the processes leading to sexual reproduction and the development of tick-stage parasites are lacking, and such tick-specific molecules can be targets for control using alternative transmission blocking vaccines. In this review, we identify and examine key phases in the life-cycle of Babesia parasites, including dependence on a tick vector for transmission, sexual reproduction of the parasite in the midgut of the tick, parasite-dependent invasion and egression of bovine RBCs, the role of the spleen in the clearance of infected RBCs (IRBCs), and age-related disease resistance in cattle, as opportunities for developing improved control measures. The availability of integrated novel research approaches including "omics" (such as genomics, transcriptomics, and proteomics), gene modification, cytoadhesion assays, RBC invasion assays and methods for in vitro induction of sexual-stage parasites will accelerate our understanding of parasite vulnerabilities. Further, producing new knowledge on these vulnerabilities, as well as taking full advantage of existing knowledge, by filling important research gaps should result in the development of next-generation vaccines to control acute disease and parasite transmission. Creative and effective use of current and future technical and computational resources are needed, in the face of the numerous challenges imposed by these highly evolved parasites, for improving the control of this disease. Overall, bovine babesiosis is recognised as a global disease that imposes a serious burden on livestock production and human livelihood, but it largely remains a poorly controlled disease in many areas of the world. Recently, important progress has been made in our understanding of the basic biology and host-parasite interactions of Babesia parasites, yet a good deal of basic and translational research is still needed to achieve effective control of this important disease and to improve animal and human health.
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Affiliation(s)
- Carlos E Suarez
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA, United States; Animal Disease Research Unit, Agricultural Research Service, USDA, WSU, Pullman, WA, United States.
| | - Heba F Alzan
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA, United States; Parasitology and Animal Diseases Department, National Research Center, Dokki, Giza, Egypt
| | - Marta G Silva
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA, United States; Animal Disease Research Unit, Agricultural Research Service, USDA, WSU, Pullman, WA, United States
| | - Vignesh Rathinasamy
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Victoria 3800, Australia
| | - William A Poole
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Victoria 3800, Australia
| | - Brian M Cooke
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Victoria 3800, Australia.
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17
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Kumar V, Behl A, Kapoor P, Nayak B, Singh G, Singh AP, Mishra S, Kang TS, Mishra PC, Hora R. Inner membrane complex 1l protein of Plasmodium falciparum links membrane lipids with cytoskeletal element 'actin' and its associated motor 'myosin'. Int J Biol Macromol 2018; 126:673-684. [PMID: 30599160 DOI: 10.1016/j.ijbiomac.2018.12.239] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 12/25/2018] [Accepted: 12/26/2018] [Indexed: 01/14/2023]
Abstract
The inner membrane complex (IMC) is a defining feature of apicomplexans comprising of lipid and protein components involved in gliding motility and host cell invasion. Motility of Plasmodium parasites is accomplished by an actin and myosin based glideosome machinery situated between the parasite plasma membrane (PPM) and IMC. Here, we have studied in vivo expression and localization of a Plasmodium falciparum (Pf) IMC protein 'PfIMC1l' and characterized it functionally by using biochemical assays. We have identified cytoskeletal protein 'actin' and motor protein 'myosin' as novel binding partners of PfIMC1l, alongside its interaction with the lipids 'cholesterol' and 'phosphatidyl-inositol 4, 5 bisphosphate' (PIP2). While actin and myosin compete for interaction with PfIMC1l, actin and either of the lipids (cholesterol or PIP2) simultaneously bind PfIMC1l. Interestingly, PfIMC1l showed enhanced binding with actin in the presence of calcium ions, and displayed direct binding with calcium. Based on our in silico analysis and experimental data showing PfIMC1l-actin/myosin and PfIMC1l-lipid interactions, we propose that this protein may anchor the IMC membrane with the parasite gliding apparatus. Considering its binding with key proteins involved in motility viz. myosin and actin (with calcium dependence), we suggest that PfIMC1l may have a role in the locomotion of Plasmodium.
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Affiliation(s)
- Vikash Kumar
- Department of Molecular Biology and Biochemistry, Guru Nanak Dev University, Amritsar, Punjab, India
| | - Ankita Behl
- Department of Biotechnology, Guru Nanak Dev University, Amritsar, Punjab, India
| | - Payal Kapoor
- Department of Molecular Biology and Biochemistry, Guru Nanak Dev University, Amritsar, Punjab, India
| | - Bandita Nayak
- CSIR-Central Drug Research Institute, Lucknow, Uttar Pradesh, India
| | - Gurbir Singh
- Department of Chemistry, Guru Nanak Dev University, Amritsar, Punjab, India
| | - Amrit Pal Singh
- Department of Pharmaceutical Science, Guru Nanak Dev University, Amritsar, Punjab, India
| | - Satish Mishra
- CSIR-Central Drug Research Institute, Lucknow, Uttar Pradesh, India
| | - Tejwant Singh Kang
- Department of Chemistry, Guru Nanak Dev University, Amritsar, Punjab, India
| | | | - Rachna Hora
- Department of Molecular Biology and Biochemistry, Guru Nanak Dev University, Amritsar, Punjab, India.
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Jalovecka M, Hajdusek O, Sojka D, Kopacek P, Malandrin L. The Complexity of Piroplasms Life Cycles. Front Cell Infect Microbiol 2018; 8:248. [PMID: 30083518 PMCID: PMC6065256 DOI: 10.3389/fcimb.2018.00248] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Accepted: 06/29/2018] [Indexed: 01/23/2023] Open
Abstract
Although apicomplexan parasites of the group Piroplasmida represent commonly identified global risks to both animals and humans, detailed knowledge of their life cycles is surprisingly limited. Such a discrepancy results from incomplete literature reports, nomenclature disunity and recently, from large numbers of newly described species. This review intends to collate and summarize current knowledge with respect to piroplasm phylogeny. Moreover, it provides a comprehensive view of developmental events of Babesia, Theileria, and Cytauxzoon representative species, focusing on uniform consensus of three consecutive phases: (i) schizogony and merogony, asexual multiplication in blood cells of the vertebrate host; (ii) gamogony, sexual reproduction inside the tick midgut, later followed by invasion of kinetes into the tick internal tissues; and (iii) sporogony, asexual proliferation in tick salivary glands resulting in the formation of sporozoites. However, many fundamental differences in this general consensus occur and this review identifies variables that should be analyzed prior to further development of specific anti-piroplasm strategies, including the attractive targeting of life cycle stages of Babesia or Theileria tick vectors.
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Affiliation(s)
- Marie Jalovecka
- BIOEPAR, INRA, Oniris, Université Bretagne Loire, Nantes, France.,Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, České Budějovice, Czechia.,Faculty of Science, University of South Bohemia, České Budějovice, Czechia
| | - Ondrej Hajdusek
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, České Budějovice, Czechia
| | - Daniel Sojka
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, České Budějovice, Czechia
| | - Petr Kopacek
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, České Budějovice, Czechia
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Immunomolecular Characterization of MIC-1, a Novel Antigen in Babesia bigemina, Which Contains Conserved and Immunodominant B-Cell Epitopes that Induce Neutralizing Antibodies. Vet Sci 2018; 5:vetsci5020032. [PMID: 29570654 PMCID: PMC6024600 DOI: 10.3390/vetsci5020032] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 03/19/2018] [Accepted: 03/21/2018] [Indexed: 11/20/2022] Open
Abstract
Babesia bigemina is one of the most prevalent species causing bovine babesiosis around the world. Antigens involved in host cell invasion are vaccine targets for this disease but are largely unknown in this species. The invasion process of Babesia spp. into erythrocytes involves membrane proteins from the apical complex. A protein stored in the micronemes, called Micronemal Protein 1 (MIC-1), contains a sialic acid binding domain that participates in the invasion process of host cells and is a vaccine candidate in other apicomplexan parasites. It is not known if there is a homologous gene for mic-1 in B. bigemina. Therefore, the aim of this study was to characterize the mic-1 gene homologue in Babesia bigemina. A gene was found with a microneme adhesive repeat (MAR) domain in the predicted amino acid sequence. Transcription was determined by reverse transcription polymerase chain reaction (RT-PCR). Subsequently, antibodies against peptides containing conserved B-cell epitopes were used to confirm the expression of MIC-1 in intraerythrocytic merozoites. The presence of anti MIC-1 antibodies in cattle naturally infected with B. bigemina was determined and up to 97.4% of the cattle sera (113 out of 116) identified MIC-1 using enzyme-linked immunosorbent assay (ELISA) methods. Finally, antibodies against MIC-1 were able to block 70% merozoite invasion in-vitro.
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20
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Targeted Phenotypic Screening in Plasmodium falciparum and Toxoplasma gondii Reveals Novel Modes of Action of Medicines for Malaria Venture Malaria Box Molecules. mSphere 2018; 3:mSphere00534-17. [PMID: 29359192 PMCID: PMC5770543 DOI: 10.1128/msphere.00534-17] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Accepted: 12/20/2017] [Indexed: 01/23/2023] Open
Abstract
The Malaria Box collection includes 400 chemically diverse small molecules with documented potency against malaria parasite growth, but the underlying modes of action are largely unknown. Using complementary phenotypic screens against Plasmodium falciparum and Toxoplasma gondii, we report phenotype-specific hits based on inhibition of overall parasite growth, apicoplast segregation, and egress or host invasion, providing hitherto unavailable insights into the possible mechanisms affected. First, the Malaria Box library was screened against tachyzoite stage T. gondii and the half-maximal effective concentrations (EC50s) of molecules showing ≥80% growth inhibition at 10 µM were determined. Comparison of the EC50s for T. gondii and P. falciparum identified a subset of 24 molecules with nanomolar potency against both parasites. Thirty molecules that failed to induce acute growth inhibition in T. gondii tachyzoites in a 2-day assay caused delayed parasite death upon extended exposure, with at least three molecules interfering with apicoplast segregation during daughter cell formation. Using flow cytometry and microscopy-based examinations, we prioritized 26 molecules with the potential to inhibit host cell egress/invasion during asexual developmental stages of P. falciparum. None of the inhibitors affected digestive vacuole integrity, ruling out a mechanism mediated by broadly specific protease inhibitor activity. Interestingly, five of the plasmodial egress inhibitors inhibited ionophore-induced egress of T. gondii tachyzoites. These findings highlight the advantage of comparative and targeted phenotypic screens in related species as a means to identify lead molecules with a conserved mode of action. Further work on target identification and mechanism analysis will facilitate the development of antiparasitic compounds with cross-species efficacy. IMPORTANCE The phylum Apicomplexa includes many human and animal pathogens, such as Plasmodium falciparum (human malaria) and Toxoplasma gondii (human and animal toxoplasmosis). Widespread resistance to current antimalarials and the lack of a commercial vaccine necessitate novel pharmacological interventions with distinct modes of action against malaria. For toxoplasmosis, new drugs to effectively eliminate tissue-dwelling latent cysts of the parasite are needed. The Malaria Box antimalarial collection, managed and distributed by the Medicines for Malaria Venture, includes molecules of novel chemical classes with proven antimalarial efficacy. Using targeted phenotypic assays of P. falciparum and T. gondii, we have identified a subset of the Malaria Box molecules as potent inhibitors of plastid segregation and parasite invasion and egress, thereby providing early insights into their probable mode of action. Five molecules that inhibit the egress of both parasites have been identified for further mechanistic studies. Thus, the approach we have used to identify novel molecules with defined modes of action in multiple parasites can expedite the development of pan-active antiparasitic agents.
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Tardieux I, Baum J. Reassessing the mechanics of parasite motility and host-cell invasion. J Cell Biol 2017; 214:507-15. [PMID: 27573462 PMCID: PMC5004448 DOI: 10.1083/jcb.201605100] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Accepted: 08/09/2016] [Indexed: 12/20/2022] Open
Abstract
The capacity to migrate is fundamental to multicellular and single-celled life. Apicomplexan parasites, an ancient protozoan clade that includes malaria parasites (Plasmodium) and Toxoplasma, achieve remarkable speeds of directional cell movement. This rapidity is achieved via a divergent actomyosin motor system, housed within a narrow compartment that lies underneath the length of the parasite plasma membrane. How this motor functions at a mechanistic level during motility and host cell invasion is a matter of debate. Here, we integrate old and new insights toward refining the current model for the function of this motor with the aim of revitalizing interest in the mechanics of how these deadly pathogens move.
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Affiliation(s)
- Isabelle Tardieux
- Institute of Advanced BioSciences, Institut National de la Santé et de la Recherche Médicale U1209, Centre National de la Recherche Scientifique UMR 5309, Université Grenoble Alpes, 38000, Grenoble, France
| | - Jake Baum
- Department of Life Sciences, Imperial College London, London SW7 2AZ, England, UK
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22
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Li P, Li J, Wang L, Di LJ. Proximity Labeling of Interacting Proteins: Application of BioID as a Discovery Tool. Proteomics 2017; 17. [DOI: 10.1002/pmic.201700002] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Revised: 02/24/2017] [Indexed: 12/31/2022]
Affiliation(s)
- Peipei Li
- Cancer Center; Faculty of Health Sciences; University of Macau; Macau SAR of China
| | - Jingjing Li
- Cancer Center; Faculty of Health Sciences; University of Macau; Macau SAR of China
| | - Li Wang
- Cancer Center; Faculty of Health Sciences; University of Macau; Macau SAR of China
- Metabolomics Core; Faculty of Health Sciences; University of Macau; Macau SAR of China
| | - Li-Jun Di
- Cancer Center; Faculty of Health Sciences; University of Macau; Macau SAR of China
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23
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Shrestha A, Palmieri N, Abd-Elfattah A, Ruttkowski B, Pagès M, Joachim A. Cloning, expression and molecular characterization of a Cystoisospora suis specific uncharacterized merozoite protein. Parasit Vectors 2017; 10:68. [PMID: 28173829 PMCID: PMC5297187 DOI: 10.1186/s13071-017-2003-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Accepted: 01/26/2017] [Indexed: 01/01/2023] Open
Abstract
Background The genome of the apicomplexan parasite Cystoisospora suis (syn. Isospora suis) has recently been sequenced and annotated, opening the possibility for the identification of novel therapeutic targets against cystoisosporosis. It was previously proposed that a 42 kDa uncharacterized merozoite protein, encoded by gene CSUI_005805, might be a relevant vaccine candidate due to its high immunogenic score, high expression level and species-specificity as determined in silico. Methods The 1170 bp coding sequence of the CSUI_005805 gene was PCR amplified and cloned into the bacterial expression vector pQE-31. The specificity of the expressed recombinant protein was evaluated in an immunoblot, and relative levels of expression in different developmental stages and subcellular localization were determined by quantitative real-time PCR and indirect immunofluorescence assay, respectively. Results The CSUI_005805 gene encoded for a 389 amino acid protein containing a histidine-rich region. Quantitative RT-PCR showed that CSUI_005805 was differentially expressed during the early development of C. suis in vitro, with higher transcript levels in merozoites compared to sporozoites. The recombinant protein was specifically recognized by sera from chicken immunized with recombinant CSUI_005805 protein and sera from piglets experimentally infected with C. suis, all of which suggested that despite prokaryotic expression, the recombinant CSUI_005805 protein maintained antigenic determinants and could elicit an immune response in the host. Immunofluorescence labelling and confocal microscopy revealed localization primarily at the surface of the parasite. Conclusions The results suggest that CSUI_005805 is highly expressed in merozoites and might thus be critical for their survival and establishment inside host cells. Owing to its specificity, localization and expression pattern, CSUI_005805 could be exploited as an attractive candidate for alternative control strategies against C. suis such as vaccines. Electronic supplementary material The online version of this article (doi:10.1186/s13071-017-2003-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Aruna Shrestha
- Institute of Parasitology, Department of Pathobiology, University of Veterinary Medicine Vienna, Veterinaerplatz 1, Vienna, A-1210, Austria
| | - Nicola Palmieri
- Institute of Parasitology, Department of Pathobiology, University of Veterinary Medicine Vienna, Veterinaerplatz 1, Vienna, A-1210, Austria
| | - Ahmed Abd-Elfattah
- Institute of Parasitology, Department of Pathobiology, University of Veterinary Medicine Vienna, Veterinaerplatz 1, Vienna, A-1210, Austria
| | - Bärbel Ruttkowski
- Institute of Parasitology, Department of Pathobiology, University of Veterinary Medicine Vienna, Veterinaerplatz 1, Vienna, A-1210, Austria
| | | | - Anja Joachim
- Institute of Parasitology, Department of Pathobiology, University of Veterinary Medicine Vienna, Veterinaerplatz 1, Vienna, A-1210, Austria.
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The p38 MAPK inhibitor, SB203580, inhibits cell invasion by Neospora caninum. Parasitol Res 2016; 116:813-819. [DOI: 10.1007/s00436-016-5346-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Accepted: 12/07/2016] [Indexed: 12/11/2022]
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Abstract
Over the past decade, major advances in imaging techniques have enhanced our understanding of Plasmodium spp. parasites and their interplay with mammalian hosts and mosquito vectors. Cryoelectron tomography, cryo-X-ray tomography and super-resolution microscopy have shifted paradigms of sporozoite and gametocyte structure, the process of erythrocyte invasion by merozoites, and the architecture of Maurer's clefts. Intravital time-lapse imaging has been revolutionary for our understanding of pre-erythrocytic stages of rodent Plasmodium parasites. Furthermore, high-speed imaging has revealed the link between sporozoite structure and motility, and improvements in time-lapse microscopy have enabled imaging of the entire Plasmodium falciparum erythrocytic cycle and the complete Plasmodium berghei pre-erythrocytic stages for the first time. In this Review, we discuss the contribution of key imaging tools to these and other discoveries in the malaria field over the past 10 years.
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Yan X, Tao G, Liu X, Ji Y, Suo X. Calcium-dependent microneme protein discharge and in vitro egress of Eimeria tenella sporozoites. Exp Parasitol 2016; 170:193-197. [PMID: 27680997 DOI: 10.1016/j.exppara.2016.09.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Revised: 09/02/2016] [Accepted: 09/15/2016] [Indexed: 11/17/2022]
Abstract
Egress is a vital step in the endogenous development of apicomplexan parasites, as it assures the parasites exit from consumed host cells and entry into fresh ones. However, little information has previously been reported on this step of Eimeria spp. In this study, we investigated in vitro egress of Eimeria tenella sporozoites triggered by acetaldehyde. We found that addition of exogenous acetaldehyde induces egress of sporozoites from primary chicken kidney cells (PCKs) and stimulate secretion of E. tenella microneme 2 protein (EtMic 2). Moreover, by using cellular calcium inhibitors, we further proved that these processes were dependent on the intracellular calcium of the parasites. Our findings provide clues to the study of interaction between eimerian parasites and their hosts.
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Affiliation(s)
- Xinlei Yan
- State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing, 100193, China; National Animal Protozoa Laboratory & College of Veterinary Medicine, China Agricultural University, Beijing, 100193, China
| | - Geru Tao
- State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing, 100193, China; National Animal Protozoa Laboratory & College of Veterinary Medicine, China Agricultural University, Beijing, 100193, China
| | - Xianyong Liu
- State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing, 100193, China; National Animal Protozoa Laboratory & College of Veterinary Medicine, China Agricultural University, Beijing, 100193, China; Key Laboratory of Zoonosis of Ministry of Agriculture & College of Veterinary Medicine, China Agricultural University, Beijing, 100193, China
| | - Yongsheng Ji
- State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing, 100193, China; National Animal Protozoa Laboratory & College of Veterinary Medicine, China Agricultural University, Beijing, 100193, China
| | - Xun Suo
- State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing, 100193, China; National Animal Protozoa Laboratory & College of Veterinary Medicine, China Agricultural University, Beijing, 100193, China; Key Laboratory of Zoonosis of Ministry of Agriculture & College of Veterinary Medicine, China Agricultural University, Beijing, 100193, China.
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In Vivo Biotinylation of the Toxoplasma Parasitophorous Vacuole Reveals Novel Dense Granule Proteins Important for Parasite Growth and Pathogenesis. mBio 2016; 7:mBio.00808-16. [PMID: 27486190 PMCID: PMC4981711 DOI: 10.1128/mbio.00808-16] [Citation(s) in RCA: 98] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Toxoplasma gondii is an obligate intracellular parasite that invades host cells and replicates within a unique parasitophorous vacuole. To maintain this intracellular niche, the parasite secretes an array of dense granule proteins (GRAs) into the nascent parasitophorous vacuole. These GRAs are believed to play key roles in vacuolar remodeling, nutrient uptake, and immune evasion while the parasite is replicating within the host cell. Despite the central role of GRAs in the Toxoplasma life cycle, only a subset of these proteins have been identified, and many of their roles have not been fully elucidated. In this report, we utilize the promiscuous biotin ligase BirA* to biotinylate GRA proteins secreted into the vacuole and then identify those proteins by affinity purification and mass spectrometry. Using GRA-BirA* fusion proteins as bait, we have identified a large number of known and candidate GRAs and verified localization of 13 novel GRA proteins by endogenous gene tagging. We proceeded to functionally characterize three related GRAs from this group (GRA38, GRA39, and GRA40) by gene knockout. While Δgra38 and Δgra40 parasites showed no altered phenotype, disruption of GRA39 results in slow-growing parasites that contain striking lipid deposits in the parasitophorous vacuole, suggesting a role in lipid regulation that is important for parasite growth. In addition, parasites lacking GRA39 showed dramatically reduced virulence and a lower tissue cyst burden in vivo. Together, the findings from this work reveal a partial vacuolar proteome of T. gondii and identify a novel GRA that plays a key role in parasite replication and pathogenesis. Most intracellular pathogens reside inside a membrane-bound vacuole within their host cell that is extensively modified by the pathogen to optimize intracellular growth and avoid host defenses. In Toxoplasma, this vacuole is modified by a host of secretory GRA proteins, many of which remain unidentified. Here we demonstrate that in vivo biotinylation of proximal and interacting proteins using the promiscuous biotin ligase BirA* is a powerful approach to rapidly identify vacuolar GRA proteins. We further demonstrate that one factor identified by this approach, GRA39, plays an important role in the ability of the parasite to replicate within its host cell and cause disease.
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Hopp CS, Balaban AE, Bushell ESC, Billker O, Rayner JC, Sinnis P. Palmitoyl transferases have critical roles in the development of mosquito and liver stages of Plasmodium. Cell Microbiol 2016; 18:1625-1641. [PMID: 27084458 DOI: 10.1111/cmi.12601] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Revised: 03/24/2016] [Accepted: 04/01/2016] [Indexed: 12/24/2022]
Abstract
As the Plasmodium parasite transitions between mammalian and mosquito host, it has to adjust quickly to new environments. Palmitoylation, a reversible and dynamic lipid post-translational modification, plays a central role in regulating this process and has been implicated with functions for parasite morphology, motility and host cell invasion. While proteins associated with the gliding motility machinery have been described to be palmitoylated, no palmitoyl transferase responsible for regulating gliding motility has previously been identified. Here, we characterize two palmityol transferases with gene tagging and gene deletion approaches. We identify DHHC3, a palmitoyl transferase, as a mediator of ookinete development, with a crucial role for gliding motility in ookinetes and sporozoites, and we co-localize the protein with a marker for the inner membrane complex in the ookinete stage. Ookinetes and sporozoites lacking DHHC3 are impaired in gliding motility and exhibit a strong phenotype in vivo; with ookinetes being significantly less infectious to their mosquito host and sporozoites being non-infectious to mice. Importantly, genetic complementation of the DHHC3-ko parasite completely restored virulence. We generated parasites lacking both DHHC3, as well as the palmitoyl transferase DHHC9, and found an enhanced phenotype for these double knockout parasites, allowing insights into the functional overlap and compensational nature of the large family of PbDHHCs. These findings contribute to our understanding of the organization and mechanism of the gliding motility machinery, which as is becoming increasingly clear, is mediated by palmitoylation.
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Affiliation(s)
- Christine S Hopp
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21205, USA. .,Wellcome Trust Sanger Institute, Hinxton, CB10 1SA, UK.
| | - Amanda E Balaban
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21205, USA
| | | | | | | | - Photini Sinnis
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21205, USA.
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Tyagi K, Hossain ME, Thakur V, Aggarwal P, Malhotra P, Mohmmed A, Sharma YD. Plasmodium vivax Tryptophan Rich Antigen PvTRAg36.6 Interacts with PvETRAMP and PvTRAg56.6 Interacts with PvMSP7 during Erythrocytic Stages of the Parasite. PLoS One 2016; 11:e0151065. [PMID: 26954579 PMCID: PMC4783080 DOI: 10.1371/journal.pone.0151065] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Accepted: 02/09/2016] [Indexed: 01/09/2023] Open
Abstract
Plasmodium vivax is most wide spread and a neglected malaria parasite. There is a lack of information on parasite biology of this species. Genome of this parasite encodes for the largest number of tryptophan-rich proteins belonging to ‘Pv-fam-a’ family and some of them are potential drug/vaccine targets but their functional role(s) largely remains unexplored. Using bacterial and yeast two hybrid systems, we have identified the interacting partners for two of the P. vivax tryptophan-rich antigens called PvTRAg36.6 and PvTRAg56.2. The PvTRAg36.6 interacts with early transcribed membrane protein (ETRAMP) of P.vivax. It is apically localized in merozoites but in early stages it is seen in parasite periphery suggesting its likely involvement in parasitophorous vacuole membrane (PVM) development or maintenance. On the other hand, PvTRAg56.2 interacts with P.vivax merozoite surface protein7 (PvMSP7) and is localized on merozoite surface. Co-localization of PvTRAg56.2 with PvMSP1 and its molecular interaction with PvMSP7 probably suggest that, PvTRAg56.2 is part of MSP-complex, and might assist or stabilize the protein complex at the merozoite surface. In conclusion, the PvTRAg proteins have different sub cellular localizations and specific associated functions during intra-erythrocytic developmental cycle.
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Affiliation(s)
- Kriti Tyagi
- Department of Biotechnology, All India Institute of Medical Sciences, New Delhi, India
| | - Mohammad Enayet Hossain
- Malaria group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
| | - Vandana Thakur
- Malaria group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
| | - Praveen Aggarwal
- Department of Emergency Medicine, All India Institute of Medical Sciences, New Delhi, India
| | - Pawan Malhotra
- Malaria group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
| | - Asif Mohmmed
- Malaria group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
- * E-mail: (YDS); (AM)
| | - Yagya Dutta Sharma
- Department of Biotechnology, All India Institute of Medical Sciences, New Delhi, India
- * E-mail: (YDS); (AM)
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Quadt KA, Streichfuss M, Moreau CA, Spatz JP, Frischknecht F. Coupling of Retrograde Flow to Force Production During Malaria Parasite Migration. ACS NANO 2016; 10:2091-2102. [PMID: 26792112 DOI: 10.1021/acsnano.5b06417] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Migration of malaria parasites is powered by a myosin motor that moves actin filaments, which in turn link to adhesive proteins spanning the plasma membrane. The retrograde flow of these adhesins appears to be coupled to forward locomotion. However, the contact dynamics between the parasite and the substrate as well as the generation of forces are complex and their relation to retrograde flow is unclear. Using optical tweezers we found retrograde flow rates up to 15 μm/s contrasting with parasite average speeds of 1-2 μm/s. We found that a surface protein, TLP, functions in reducing retrograde flow for the buildup of adhesive force and that actin dynamics appear optimized for the generation of force but not for maximizing the speed of retrograde flow. These data uncover that TLP acts by modulating actin dynamics or actin filament organization and couples retrograde flow to force production in malaria parasites.
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Affiliation(s)
- Katharina A Quadt
- Integrative Parasitology, Center for Infectious Diseases, University of Heidelberg Medical School , Im Neuenheimer Feld 324, 69120 Heidelberg, Germany
| | - Martin Streichfuss
- Integrative Parasitology, Center for Infectious Diseases, University of Heidelberg Medical School , Im Neuenheimer Feld 324, 69120 Heidelberg, Germany
- University of Heidelberg , Department of Biophysical Chemistry and Max Planck Institute for Intelligent Systems, Department of New Materials and Biosystems, Heisenbergstr. 3, 70569 Stuttgart, Germany
| | - Catherine A Moreau
- Integrative Parasitology, Center for Infectious Diseases, University of Heidelberg Medical School , Im Neuenheimer Feld 324, 69120 Heidelberg, Germany
| | - Joachim P Spatz
- University of Heidelberg , Department of Biophysical Chemistry and Max Planck Institute for Intelligent Systems, Department of New Materials and Biosystems, Heisenbergstr. 3, 70569 Stuttgart, Germany
| | - Friedrich Frischknecht
- Integrative Parasitology, Center for Infectious Diseases, University of Heidelberg Medical School , Im Neuenheimer Feld 324, 69120 Heidelberg, Germany
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Baumeister S, Gangopadhyay P, Repnik U, Lingelbach K. Novel insights into red blood cell physiology using parasites as tools. Eur J Cell Biol 2015; 94:332-9. [DOI: 10.1016/j.ejcb.2015.05.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
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32
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Zhang Y, Jiang N, Jia B, Chang Z, Zhang Y, Wei X, Zhou J, Wang H, Zhao X, Yu S, Song M, Tu Z, Lu H, Yin J, Wahlgren M, Chen Q. A comparative study on the heparin-binding proteomes of Toxoplasma gondii and Plasmodium falciparum. Proteomics 2014; 14:1737-45. [PMID: 24888565 DOI: 10.1002/pmic.201400003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2014] [Revised: 05/06/2014] [Accepted: 05/22/2014] [Indexed: 11/09/2022]
Abstract
Toxoplasma gondii is an obligatory intracellular apicomplexan parasite which exploits host cell surface components in cell invasion and intracellular parasitization. Sulfated glycans such as heparin and heparan sulfate have been reported to inhibit cell invasion by T. gondii and other apicomplexan parasites such as Plasmodium falciparum. The aim of this study was to investigate the heparin-binding proteome of T. gondii. The parasite-derived components were affinity-purified on the heparin moiety followed by MS fingerprinting of the proteins. The heparin-binding proteins of T. gondii and P. falciparum were compared based on functionality and affinity to heparin. Among the proteins identified, the invasion-related parasite ligands derived from tachyzoite/merozoite surface and the secretory organelles were prominent. However, the profiles of the proteins were different in terms of affinity to heparin. In T. gondii, the proteins with highest affinity to heparin were the intracellular components with functions of parasite development contrasted to that of P. falciparum, of which the rhoptry-derived proteins were prominently identified. The profiling of the heparin-binding proteins of the two apicomplexan parasites not only explained the mechanism of heparin-mediated host cell invasion inhibition, but also, to a certain extent, revealed that the action of heparin on the parasite extended after endocytosis.
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Affiliation(s)
- Yan Zhang
- Key Laboratory of Zoonosis, Jilin University, Changchun, P. R. China; Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Institute of Military Veterinary, Academy of Military Medical Sciences, Changchun, P. R. China
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Kan A, Tan YH, Angrisano F, Hanssen E, Rogers KL, Whitehead L, Mollard VP, Cozijnsen A, Delves MJ, Crawford S, Sinden RE, McFadden GI, Leckie C, Bailey J, Baum J. Quantitative analysis of Plasmodium ookinete motion in three dimensions suggests a critical role for cell shape in the biomechanics of malaria parasite gliding motility. Cell Microbiol 2014; 16:734-50. [PMID: 24612056 PMCID: PMC4286792 DOI: 10.1111/cmi.12283] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Revised: 01/22/2014] [Accepted: 02/13/2014] [Indexed: 11/28/2022]
Abstract
Motility is a fundamental part of cellular life and survival, including for Plasmodium parasites--single-celled protozoan pathogens responsible for human malaria. The motile life cycle forms achieve motility, called gliding, via the activity of an internal actomyosin motor. Although gliding is based on the well-studied system of actin and myosin, its core biomechanics are not completely understood. Currently accepted models suggest it results from a specifically organized cellular motor that produces a rearward directional force. When linked to surface-bound adhesins, this force is passaged to the cell posterior, propelling the parasite forwards. Gliding motility is observed in all three life cycle stages of Plasmodium: sporozoites, merozoites and ookinetes. However, it is only the ookinetes--formed inside the midgut of infected mosquitoes--that display continuous gliding without the necessity of host cell entry. This makes them ideal candidates for invasion-free biomechanical analysis. Here we apply a plate-based imaging approach to study ookinete motion in three-dimensional (3D) space to understand Plasmodium cell motility and how movement facilitates midgut colonization. Using single-cell tracking and numerical analysis of parasite motion in 3D, our analysis demonstrates that ookinetes move with a conserved left-handed helical trajectory. Investigation of cell morphology suggests this trajectory may be based on the ookinete subpellicular cytoskeleton, with complementary whole and subcellular electron microscopy showing that, like their motion paths, ookinetes share a conserved left-handed corkscrew shape and underlying twisted microtubular architecture. Through comparisons of 3D movement between wild-type ookinetes and a cytoskeleton-knockout mutant we demonstrate that perturbation of cell shape changes motion from helical to broadly linear. Therefore, while the precise linkages between cellular architecture and actomyosin motor organization remain unknown, our analysis suggests that the molecular basis of cell shape may, in addition to motor force, be a key adaptive strategy for malaria parasite dissemination and, as such, transmission.
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Affiliation(s)
- Andrey Kan
- Victoria Research Laboratory, National ICT Australia (NICTA), Department of Computing and Information Systems, University of Melbourne, Melbourne, Vic., 3010, Australia
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Offeddu V, Rauch M, Silvie O, Matuschewski K. The Plasmodium protein P113 supports efficient sporozoite to liver stage conversion in vivo. Mol Biochem Parasitol 2014; 193:101-9. [DOI: 10.1016/j.molbiopara.2014.03.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Revised: 03/01/2014] [Accepted: 03/03/2014] [Indexed: 10/25/2022]
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Role of gap junctions and hemichannels in parasitic infections. BIOMED RESEARCH INTERNATIONAL 2013; 2013:589130. [PMID: 24236292 PMCID: PMC3819887 DOI: 10.1155/2013/589130] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Revised: 08/07/2013] [Accepted: 08/26/2013] [Indexed: 02/06/2023]
Abstract
In vertebrates, connexins (Cxs) and pannexins (Panxs) are proteins that form gap junction channels and/or hemichannels located at cell-cell interfaces and cell surface, respectively. Similar channel types are formed by innexins in invertebrate cells. These channels serve as pathways for cellular communication that coordinate diverse physiologic processes. However, it is known that many acquired and inherited diseases deregulate Cx and/or Panx channels, condition that frequently worsens the pathological state of vertebrates. Recent evidences suggest that Cx and/or Panx hemichannels play a relevant role in bacterial and viral infections. Nonetheless, little is known about the role of Cx- and Panx-based channels in parasitic infections of vertebrates. In this review, available data on changes in Cx and gap junction channel changes induced by parasitic infections are summarized. Additionally, we describe recent findings that suggest possible roles of hemichannels in parasitic infections. Finally, the possibility of new therapeutic designs based on hemichannel blokers is presented.
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Mendes T, Lobo F, Rodrigues T, Rodrigues-Luiz G, daRocha W, Fujiwara R, Teixeira S, Bartholomeu D. Repeat-Enriched Proteins Are Related to Host Cell Invasion and Immune Evasion in Parasitic Protozoa. Mol Biol Evol 2013; 30:951-63. [DOI: 10.1093/molbev/mst001] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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37
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Abstract
Invasion of the central nervous system (CNS) is a most devastating complication of a parasitic infection. Several physical and immunological barriers provide obstacles to such an invasion. In this broad overview focus is given to the physical barriers to neuroinvasion of parasites provided at the portal of entry of the parasites, i.e., the skin and epithelial cells of the gastrointestinal tract, and between the blood and the brain parenchyma, i.e., the blood-brain barrier (BBB). A description is given on how human pathogenic parasites can reach the CNS via the bloodstream either as free-living or extracellular parasites, by embolization of eggs, or within red or white blood cells when adapted to intracellular life. Molecular mechanisms are discussed by which parasites can interact with or pass across the BBB. The possible targeting of the circumventricular organs by parasites, as well as the parasites' direct entry to the brain from the nasal cavity through the olfactory nerve pathway, is also highlighted. Finally, examples are given which illustrate different mechanisms by which parasites can cause dysfunction or damage in the CNS related to toxic effects of parasite-derived molecules or to immune responses to the infection.
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Evolution of apicomplexan secretory organelles. Int J Parasitol 2012; 42:1071-81. [PMID: 23068912 DOI: 10.1016/j.ijpara.2012.09.009] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2012] [Revised: 09/16/2012] [Accepted: 09/17/2012] [Indexed: 12/26/2022]
Abstract
The alveolate superphylum includes many free-living and parasitic organisms, which are united by the presence of alveolar sacs lying proximal to the plasma membrane, providing cell structure. All species comprising the apicomplexan group of alveolates are parasites and have adapted to the unique requirements of the parasitic lifestyle. Here the evolution of apicomplexan secretory organelles that are involved in the critical process of egress from one cell and invasion of another is explored. The variations within the Apicomplexa and how these relate to species-specific biology will be discussed. In addition, recent studies have identified specific calcium-sensitive molecules that coordinate the various events and regulate the release of these secretory organelles within apicomplexan parasites. Some aspects of this machinery are conserved outside the Apicomplexa, and are beginning to elucidate the conserved nature of the machinery. Briefly, the relationship of this secretion machinery within the Apicomplexa will be discussed, compared with free-living and predatory alveolates, and how these might have evolved from a common ancestor.
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Azzouz N, Kamena F, Laurino P, Kikkeri R, Mercier C, Cesbron-Delauw MF, Dubremetz JF, De Cola L, Seeberger PH. Toxoplasma gondii secretory proteins bind to sulfated heparin structures. Glycobiology 2012; 23:106-20. [DOI: 10.1093/glycob/cws134] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
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40
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Cabrera A, Herrmann S, Warszta D, Santos JM, John Peter AT, Kono M, Debrouver S, Jacobs T, Spielmann T, Ungermann C, Soldati-Favre D, Gilberger TW. Dissection of minimal sequence requirements for rhoptry membrane targeting in the malaria parasite. Traffic 2012; 13:1335-50. [PMID: 22759070 DOI: 10.1111/j.1600-0854.2012.01394.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2012] [Revised: 06/28/2012] [Accepted: 07/03/2012] [Indexed: 12/20/2022]
Abstract
Rhoptries are specialized secretory organelles characteristic of single cell organisms belonging to the clade Apicomplexa. These organelles play a key role in the invasion process of host cells by accumulating and subsequently secreting an unknown number of proteins mediating host cell entry. Despite their essential role, little is known about their biogenesis, components and targeting determinants. Here, we report on a conserved apicomplexan protein termed Armadillo Repeats-Only (ARO) protein that we localized to the cytosolic face of Plasmodium falciparum and Toxoplasma gondii rhoptries. We show that the first 20 N-terminal amino acids are sufficient for rhoptry membrane targeting. This protein relies on both - myristoylation and palmitoylation motifs - for membrane attachment. Although these lipid modifications are essential, they are not sufficient to direct ARO to the rhoptry membranes. Mutational analysis revealed additional residues within the first 20 amino acids of ARO that play an important role for rhoptry membrane attachment: the positively charged residues R9 and K14. Interestingly, the exchange of R9 with a negative charge entirely abolishes membrane attachment, whereas the exchange of K14 (and to a lesser extent K16) alters only its membrane specificity. Additionally, 17 proteins predicted to be myristoylated and palmitoylated in the first 20 N-terminal amino acids were identified in the genome of the malaria parasite. While most of the corresponding GFP fusion proteins were trafficked to the parasite plasma membrane, two were sorted to the apical organelles. Interestingly, these proteins have a similar motif identified for ARO.
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Affiliation(s)
- Ana Cabrera
- M.G. DeGroote Institute for Infectious Disease Research, Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada
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Kono M, Herrmann S, Loughran NB, Cabrera A, Engelberg K, Lehmann C, Sinha D, Prinz B, Ruch U, Heussler V, Spielmann T, Parkinson J, Gilberger TW. Evolution and architecture of the inner membrane complex in asexual and sexual stages of the malaria parasite. Mol Biol Evol 2012; 29:2113-32. [PMID: 22389454 DOI: 10.1093/molbev/mss081] [Citation(s) in RCA: 90] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The inner membrane complex (IMC) is a unifying morphological feature of all alveolate organisms. It consists of flattened vesicles underlying the plasma membrane and is interconnected with the cytoskeleton. Depending on the ecological niche of the organisms, the function of the IMC ranges from a fundamental role as reinforcement system to more specialized roles in motility and cytokinesis. In this article, we present a comprehensive evolutionary analysis of IMC components, which exemplifies the adaptive nature of the IMCs' protein composition. Focusing on eight structurally distinct proteins in the most prominent "genus" of the Alveolata-the malaria parasite Plasmodium-we demonstrate that the level of conservation is reflected in phenotypic characteristics, accentuated in differential spatial-temporal patterns of these proteins in the motile stages of the parasite's life cycle. Colocalization studies with the centromere and the spindle apparatus reveal their discriminative biogenesis. We also reveal that the IMC is an essential structural compartment for the development of the sexual stages of Plasmodium, as it seems to drive the morphological changes of the parasite during the long and multistaged process of sexual differentiation. We further found a Plasmodium-specific IMC membrane matrix protein that highlights transversal structures in gametocytes, which could represent a genus-specific structural innovation required by Plasmodium. We conclude that the IMC has an additional role during sexual development supporting morphogenesis of the cell, which in addition to its functions in the asexual stages highlights the multifunctional nature of the IMC in the Plasmodium life cycle.
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Affiliation(s)
- Maya Kono
- Department of Molecular Parasitology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
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Plattner H, Sehring IM, Mohamed IK, Miranda K, De Souza W, Billington R, Genazzani A, Ladenburger EM. Calcium signaling in closely related protozoan groups (Alveolata): non-parasitic ciliates (Paramecium, Tetrahymena) vs. parasitic Apicomplexa (Plasmodium, Toxoplasma). Cell Calcium 2012; 51:351-82. [PMID: 22387010 DOI: 10.1016/j.ceca.2012.01.006] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2011] [Revised: 01/10/2012] [Accepted: 01/12/2012] [Indexed: 12/20/2022]
Abstract
The importance of Ca2+-signaling for many subcellular processes is well established in higher eukaryotes, whereas information about protozoa is restricted. Recent genome analyses have stimulated such work also with Alveolates, such as ciliates (Paramecium, Tetrahymena) and their pathogenic close relatives, the Apicomplexa (Plasmodium, Toxoplasma). Here we compare Ca2+ signaling in the two closely related groups. Acidic Ca2+ stores have been characterized in detail in Apicomplexa, but hardly in ciliates. Two-pore channels engaged in Ca2+-release from acidic stores in higher eukaryotes have not been stingently characterized in either group. Both groups are endowed with plasma membrane- and endoplasmic reticulum-type Ca2+-ATPases (PMCA, SERCA), respectively. Only recently was it possible to identify in Paramecium a number of homologs of ryanodine and inositol 1,3,4-trisphosphate receptors (RyR, IP3R) and to localize them to widely different organelles participating in vesicle trafficking. For Apicomplexa, physiological experiments suggest the presence of related channels although their identity remains elusive. In Paramecium, IP3Rs are constitutively active in the contractile vacuole complex; RyR-related channels in alveolar sacs are activated during exocytosis stimulation, whereas in the parasites the homologous structure (inner membrane complex) may no longer function as a Ca2+ store. Scrutinized comparison of the two closely related protozoan phyla may stimulate further work and elucidate adaptation to parasitic life. See also "Conclusions" section.
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Affiliation(s)
- H Plattner
- Department of Biology, University of Konstanz, P.O. Box 5560, 78457 Konstanz, Germany.
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Li H, Child MA, Bogyo M. Proteases as regulators of pathogenesis: examples from the Apicomplexa. BIOCHIMICA ET BIOPHYSICA ACTA 2012; 1824:177-85. [PMID: 21683169 PMCID: PMC3232290 DOI: 10.1016/j.bbapap.2011.06.002] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2011] [Revised: 06/01/2011] [Accepted: 06/02/2011] [Indexed: 11/20/2022]
Abstract
The diverse functional roles that proteases play in basic biological processes make them essential for virtually all organisms. Not surprisingly, proteolysis is also a critical process required for many aspects of pathogenesis. In particular, obligate intracellular parasites must precisely coordinate proteolytic events during their highly regulated life cycle inside multiple host cell environments. Advances in chemical, proteomic and genetic tools that can be applied to parasite biology have led to an increased understanding of the complex events centrally regulated by proteases. In this review, we outline recent advances in our knowledge of specific proteolytic enzymes in two medically relevant apicomplexan parasites: Plasmodium falciparum and Toxoplasma gondii. Efforts over the last decade have begun to provide a map of key proteotolyic events that are essential for both parasite survival and propagation inside host cells. These advances in our molecular understanding of proteolytic events involved in parasite pathogenesis provide a foundation for the validation of new networks and enzyme targets that could be exploited for therapeutic purposes. This article is part of a Special Issue entitled: Proteolysis 50 years after the discovery of lysosome.
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Affiliation(s)
- Hao Li
- Departments of Pathology and Microbiology and Immunology and Graduate program in Chemical and Systems Biology, Stanford University, 300 Pasteur Dr. Stanford, CA. 94305
| | - Matthew A. Child
- Departments of Pathology and Microbiology and Immunology and Graduate program in Chemical and Systems Biology, Stanford University, 300 Pasteur Dr. Stanford, CA. 94305
| | - Matthew Bogyo
- Departments of Pathology and Microbiology and Immunology and Graduate program in Chemical and Systems Biology, Stanford University, 300 Pasteur Dr. Stanford, CA. 94305
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Labeling surface epitopes to identify Cryptosporidium life stages using a scanning electron microscopy-based immunogold approach. Mol Cell Probes 2011; 26:21-8. [PMID: 22100878 DOI: 10.1016/j.mcp.2011.11.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2011] [Revised: 11/02/2011] [Accepted: 11/02/2011] [Indexed: 11/22/2022]
Abstract
The Apicomplexan parasite Cryptosporidium parvum is responsible for the widespread disease cryptosporidiosis, in both humans and livestock. The nature of C. parvum infection is far from understood and many questions remain in regard to host-parasite interactions, limiting successful treatment of the disease. To definitively identify a range of C. parvum stages in cell culture and to begin to investigate host cell interactions in some of the lesser known life stages, we have utilized a combined scanning electron microscopy and immunolabeling approach, correlating high resolution microstructural information with definitive immunogold labeling of Cryptosporidium stages. Several life cycle stages, including oocysts, merozoites I, trophozoites, gamonts and microgametocytes, were successfully immunolabeled in an in vitro model system. Developing oocysts were clearly immunolabeled, but this did not persist once excystation had occurred. Immunolabeling visualized on the host cell surface adjacent to invasive merozoites is likely to be indicative of receptor shedding, with merozoites also initiating host responses that manifested as abnormal microvilli on the host cell surface. Small sub-micron stages such as microgametocytes, which were impossible to identify as single entities without immunolabeling, were readily visualized and observed to attach to host cells via novel membranous projections. Epicellular parasites also expressed Cryptosporidium-derived epitopes within their encapsulating membrane. These data have allowed us to confidently identify a variety of C. parvum stages in cell culture at high resolution. With this, we provide new insight into C. parvum - host cell interactions and highlight future opportunities for investigating and targeting receptor-mediated interactions between Cryptosporidium life cycle stages and host cells.
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Comparison of protective immune responses to apicomplexan parasites. J Parasitol Res 2011; 2012:852591. [PMID: 21876783 PMCID: PMC3159010 DOI: 10.1155/2012/852591] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2011] [Accepted: 06/27/2011] [Indexed: 12/02/2022] Open
Abstract
Members of the phylum Apicomplexa, which includes the species Plasmodium, Eimeria, Toxoplasma, and Babesia amongst others, are the most successful intracellular pathogens known to humankind. The widespread acquisition of antimicrobial resistance to most drugs used to date has sparked a great deal of research and commercial interest in the development of vaccines as alternative control strategies. A few antigens from the asexual and sexual stages of apicomplexan development have been identified and their genes characterised; however, the fine cellular and molecular details of the effector mechanisms crucial for parasite inhibition and stimulation of protective immunity are still not entirely understood. This paper provides an overview of what is currently known about the protective immune response against the various types of apicomplexan parasites and focuses mainly on the similarities of these pathogens and their host interaction. Finally, the evolutionary relationships of these parasites and their hosts, as well as the modulation of immune functions that are critical in determining the outcome of the infection by these pathogenic organisms, are discussed.
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Ramakrishnan C, Dessens JT, Armson R, Pinto SB, Talman AM, Blagborough AM, Sinden RE. Vital functions of the malarial ookinete protein, CTRP, reside in the A domains. Int J Parasitol 2011; 41:1029-39. [PMID: 21729699 DOI: 10.1016/j.ijpara.2011.05.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2011] [Revised: 05/04/2011] [Accepted: 05/06/2011] [Indexed: 10/18/2022]
Abstract
The transformation of malaria ookinetes into oocysts occurs in the mosquito midgut and is a major bottleneck for parasite transmission. The secreted ookinete surface protein, circumsporozoite- and thrombospondin-related adhesive protein (TRAP)-related protein (CTRP), is essential for this transition and hence constitutes a potential target for malaria transmission blockade. CTRP is a modular multidomain protein containing six tandem von Willebrand factor A-like (A) domains and seven tandem thrombospondin type I repeat-like (TS) domains. Here we present, to our knowledge, the first structure-function analysis of CTRP using genetically modified Plasmodium berghei parasites expressing mutant versions of the ctrp gene. Our data show that the A domains of CTRP are critical for ookinete gliding motility and oocyst formation whilst, unexpectedly, its TS domains are fully redundant. These results may have important implications for the design of CTRP-based transmission blocking strategies.
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Affiliation(s)
- Chandra Ramakrishnan
- Division of Cell and Molecular Biology, Sir Alexander Fleming Building, Imperial College London, South Kensington Campus, London SW72AZ, UK.
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Computational identification of signalling pathways in Plasmodium falciparum. INFECTION GENETICS AND EVOLUTION 2011; 11:755-64. [DOI: 10.1016/j.meegid.2010.11.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2010] [Revised: 11/17/2010] [Accepted: 11/18/2010] [Indexed: 11/20/2022]
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Goh MY, Pan MZ, Blake DP, Wan KL, Song BK. Eimeria maxima phosphatidylinositol 4-phosphate 5-kinase: locus sequencing, characterization, and cross-phylum comparison. Parasitol Res 2011; 108:611-20. [PMID: 20938684 DOI: 10.1007/s00436-010-2104-7] [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: 09/05/2010] [Accepted: 09/23/2010] [Indexed: 10/19/2022]
Abstract
Phosphatidylinositol 4-phosphate 5-kinase (PIP5K) may play an important role in host-cell invasion by the Eimeria species, protozoan parasites which can cause severe intestinal disease in livestock. Here, we report the structural organization of the PIP5K gene in Eimeria maxima (Weybridge strain). Two E. maxima BAC clones carrying the E. maxima PIP5K (EmPIP5K) coding sequences were selected for shotgun sequencing, yielding a 9.1-kb genomic segment. The EmPIP5K coding region was initially identified using in silico gene-prediction approaches and subsequently confirmed by mapping rapid amplification of cDNA ends and RT-PCR-generated cDNA sequence to its genomic segment. The putative EmPIP5K gene was located at position 710-8036 nt on the complimentary strand and comprised of 23 exons. Alignment of the 1147 amino acid sequence with previously annotated PIP5K proteins from other Apicomplexa species detected three conserved motifs encompassing the kinase core domain, which has been shown by previous protein deletion studies to be necessary for PIP5K protein function. Phylogenetic analysis provided further evidence that the putative EmPIP5K protein is orthologous to that of other Apicomplexa. Subsequent comparative gene structure characterization revealed events of intron loss/gain throughout the evolution of the apicomplexan PIP5K gene. Further scrutiny of the genomic structure revealed a possible trend towards "intron gain" between two of the motif regions. Our findings offer preliminary insights into the structural variations that have occurred during the evolution of the PIP5K locus and may aid in understanding the functional role of this gene in the cellular biology of apicomplexan parasites.
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Affiliation(s)
- Mei-Yen Goh
- School of Science, Monash University Sunway Campus, Jalan Lagoon Selatan, 46150 Bandar Sunway, Selangor, DE, Malaysia
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Dvorin JD, Bei AK, Coleman BI, Duraisingh MT. Functional diversification between two related Plasmodium falciparum merozoite invasion ligands is determined by changes in the cytoplasmic domain. Mol Microbiol 2010; 75:990-1006. [PMID: 20487292 DOI: 10.1111/j.1365-2958.2009.07040.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The pathogenesis of Plasmodium falciparum depends on efficient invasion into host erythrocytes. Parasite ligands encoded by multi-gene families interact with erythrocyte receptors. P. falciparum reticulocyte binding protein homologues (PfRhs) are expressed at the apical surface of invasive merozoites and have divergent ectodomains that are postulated to bind different erythrocyte receptors. Variant expression of these paralogues results in the use of alternative invasion pathways. Two PfRh proteins, PfRh2a and PfRh2b, are identical for 2700 N-terminal amino acids and differ only in a C-terminal 500 amino acid region, which includes a unique ectodomain, transmembrane domain and cytoplasmic domain. Despite their similarity, PfRh2b is required for a well-defined invasion pathway while PfRh2a is not required or sufficient for this pathway. Mapping the genomic region encoding these proteins revealed a recombinogenic locus with PfRh2a and PfRh2b in a head-to-head orientation. We have generated viable PfRh2a/2b chimeric parasites to identify the regions required for alternative invasion pathway utilization. We find that the differential ability to use these pathways is conferred by the cytoplasmic domains of PfRh2a and PfRh2b, not the ectodomain or transmembrane regions. Our results highlight the importance of the cytoplasmic domain for functional diversification of a major adhesive ligand family in malaria parasites.
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Affiliation(s)
- Jeffrey D Dvorin
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, MA 02115, USA
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50
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Proellocks NI, Coppel RL, Waller KL. Dissecting the apicomplexan rhoptry neck proteins. Trends Parasitol 2010; 26:297-304. [PMID: 20347614 DOI: 10.1016/j.pt.2010.02.012] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2009] [Revised: 11/13/2009] [Accepted: 02/26/2010] [Indexed: 10/19/2022]
Abstract
Apicomplexan parasites possess specialized secretory organelles (rhoptries and micronemes) that release their contents during host cell invasion. Although the rhoptries were once thought to be merely a bulbous 'protein reservoir' connected to an anterior neck region, the localization of a protein specifically to the neck suggested that this region was more than just a duct. Recent studies have shown that the rhoptry neck sub-compartment possesses a distinct protein repertoire. Some of these proteins share common features, including conservation across the phylum and involvement in tight-junction formation. A sub-group of rhoptry neck proteins, the RONs, their association with the microneme protein apical membrane antigen AMA1, and their involvement in invasion are discussed.
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