1
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Nasuhidehnavi A, Yap GS. To kill a tachyzoite: assault and battery. Trends Parasitol 2024; 40:449-451. [PMID: 38762372 PMCID: PMC11156527 DOI: 10.1016/j.pt.2024.05.002] [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: 05/02/2024] [Accepted: 05/03/2024] [Indexed: 05/20/2024]
Abstract
Polymeric guanylate-binding proteins (GBPs) physically dismember the vacuole membrane formed by Toxoplasma gondii while nitric oxide (NO) poisons and inhibits parasite replication within interferon (IFN)-γ activated macrophages. Zhao et al. report a novel mechanism for synergy between these classical microbicidal and microbistatic effectors in cell-autonomous immunity to the intracellular parasites.
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Affiliation(s)
- Azadeh Nasuhidehnavi
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - George S Yap
- Center for Immunity and Inflammation, Department of Medicine, New Jersey Medical School, Rutgers University, Newark, NJ, USA.
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2
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Zhao XY, Lempke SL, Urbán Arroyo JC, Brown IG, Yin B, Magaj MM, Holness NK, Smiley J, Redemann S, Ewald SE. iNOS is necessary for GBP-mediated T. gondii clearance in murine macrophages via vacuole nitration and intravacuolar network collapse. Nat Commun 2024; 15:2698. [PMID: 38538595 PMCID: PMC10973475 DOI: 10.1038/s41467-024-46790-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Accepted: 03/04/2024] [Indexed: 04/02/2024] Open
Abstract
Toxoplasma gondii is an obligate intracellular parasite of rodents and humans. Interferon-inducible guanylate binding proteins (GBPs) are mediators of T. gondii clearance, however, this mechanism is incomplete. Here, using automated spatially targeted optical micro proteomics we demonstrate that inducible nitric oxide synthetase (iNOS) is highly enriched at GBP2+ parasitophorous vacuoles (PV) in murine macrophages. iNOS expression in macrophages is necessary to limit T. gondii load in vivo and in vitro. Although iNOS activity is dispensable for GBP2 recruitment and PV membrane ruffling; parasites can replicate, egress and shed GBP2 when iNOS is inhibited. T. gondii clearance by iNOS requires nitric oxide, leading to nitration of the PV and collapse of the intravacuolar network of membranes in a chromosome 3 GBP-dependent manner. We conclude that reactive nitrogen species generated by iNOS cooperate with GBPs to target distinct structures in the PV that are necessary for optimal parasite clearance in macrophages.
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Affiliation(s)
- Xiao-Yu Zhao
- Department of Microbiology, Immunology, and Cancer Biology at the Carter Immunology Center, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Samantha L Lempke
- Department of Microbiology, Immunology, and Cancer Biology at the Carter Immunology Center, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Jan C Urbán Arroyo
- Department of Microbiology, Immunology, and Cancer Biology at the Carter Immunology Center, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Isabel G Brown
- Department of Microbiology, Immunology, and Cancer Biology at the Carter Immunology Center, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Bocheng Yin
- Department of Microbiology, Immunology, and Cancer Biology at the Carter Immunology Center, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Magdalena M Magaj
- Center for Membrane and Cell Physiology, Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Nadia K Holness
- Department of Microbiology, Immunology, and Cancer Biology at the Carter Immunology Center, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Jamison Smiley
- Department of Microbiology, Immunology, and Cancer Biology at the Carter Immunology Center, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Stefanie Redemann
- Center for Membrane and Cell Physiology, Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Sarah E Ewald
- Department of Microbiology, Immunology, and Cancer Biology at the Carter Immunology Center, University of Virginia School of Medicine, Charlottesville, VA, USA.
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3
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Zhao XY, Lempke SL, Urbán Arroyo JC, Yin B, Holness NK, Smiley J, Ewald SE. Inducible nitric oxide synthase (iNOS) is necessary for GBP-mediated T. gondii restriction in murine macrophages via vacuole nitration and intravacuolar network collapse. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.24.549965. [PMID: 37546987 PMCID: PMC10402109 DOI: 10.1101/2023.07.24.549965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/08/2023]
Abstract
Toxoplasma gondii is an obligate intracellular, protozoan pathogen of rodents and humans. T. gondii's ability to grow within cells and evade cell-autonomous immunity depends on the integrity of the parasitophorous vacuole (PV). Interferon-inducible guanylate binding proteins (GBPs) are central mediators of T. gondii clearance, however, the precise mechanism linking GBP recruitment to the PV and T. gondii restriction is not clear. This knowledge gap is linked to heterogenous GBP-targeting across a population of vacuoles and the lack of tools to selectively purify the intact PV. To identify mediators of parasite clearance associated with GBP2-positive vacuoles, we employed a novel protein discovery tool automated spatially targeted optical micro proteomics (autoSTOMP). This approach identified inducible nitric oxide synthetase (iNOS) enriched at levels similar to the GBPs in infected bone marrow-derived myeloid cells. iNOS expression on myeloid cells was necessary for mice to control T. gondii growth in vivo and survive acute infection. T. gondii infection of IFNγ-primed macrophage was sufficient to robustly induce iNOS expression. iNOS restricted T. gondii infection through nitric oxide synthesis rather than arginine depletion, leading to robust and selective nitration of the PV. Optimal parasite restriction by iNOS and vacuole nitration depended on the chromosome 3 GBPs. Notably, GBP2 recruitment and ruffling of the PV membrane occurred in iNOS knockouts, however, these vacuoles contained dividing parasites. iNOS activity was necessary for the collapse of the intravacuolar network of nanotubular membranes which connects parasites to each other and the host cytosol. Based on these data we conclude reactive nitrogen species generated by iNOS cooperate with the chromosome 3 GBPs to target distinct biology of the PV that are necessary for optimal parasite clearance in murine myeloid cells.
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Affiliation(s)
- Xiao-Yu Zhao
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, Charlottesville, Virginia, USA
- The Carter Immunology Center, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Samantha L. Lempke
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, Charlottesville, Virginia, USA
- The Carter Immunology Center, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Jan C. Urbán Arroyo
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, Charlottesville, Virginia, USA
- The Carter Immunology Center, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Bocheng Yin
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, Charlottesville, Virginia, USA
- The Carter Immunology Center, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Nadia K. Holness
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, Charlottesville, Virginia, USA
- The Carter Immunology Center, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Jamison Smiley
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, Charlottesville, Virginia, USA
- The Carter Immunology Center, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Sarah E. Ewald
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, Charlottesville, Virginia, USA
- The Carter Immunology Center, University of Virginia School of Medicine, Charlottesville, Virginia, USA
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4
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Romano JD, Mayoral J, Guevara RB, Rivera-Cuevas Y, Carruthers VB, Weiss LM, Coppens I. Toxoplasma gondii scavenges mammalian host organelles through the usurpation of host ESCRT-III and Vps4A. J Cell Sci 2023; 136:jcs260159. [PMID: 36718630 PMCID: PMC10022688 DOI: 10.1242/jcs.260159] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 01/19/2023] [Indexed: 02/01/2023] Open
Abstract
Intracellular pathogens exploit cellular resources through host cell manipulation. Within its nonfusogenic parasitophorous vacuole (PV), Toxoplasma gondii targets host nutrient-filled organelles and sequesters them into the PV through deep invaginations of the PV membrane (PVM) that ultimately detach from this membrane. Some of these invaginations are generated by an intravacuolar network (IVN) of parasite-derived tubules attached to the PVM. Here, we examined the usurpation of host ESCRT-III and Vps4A by the parasite to create PVM buds and vesicles. CHMP4B associated with the PVM/IVN, and dominant-negative (DN) CHMP4B formed many long PVM invaginations containing CHMP4B filaments. These invaginations were shorter in IVN-deficient parasites, suggesting cooperation between the IVN and ESCRT. In infected cells expressing Vps4A-DN, enlarged intra-PV structures containing host endolysosomes accumulated, reflecting defects in PVM scission. Parasite mutants lacking T. gondii (Tg)GRA14 or TgGRA64, which interact with ESCRT, reduced CHMP4B-DN-induced PVM invaginations and intra-PV host organelles, with greater defects in a double knockout, revealing the exploitation of ESCRT to scavenge host organelles by Toxoplasma.
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Affiliation(s)
- Julia D. Romano
- Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD 21205, USA
| | - Joshua Mayoral
- Department of Pathology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Rebekah B. Guevara
- Department of Pathology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Yolanda Rivera-Cuevas
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Vern B. Carruthers
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Louis M. Weiss
- Department of Pathology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Isabelle Coppens
- Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD 21205, USA
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5
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A. PORTES JULIANA, C. VOMMARO ROSSIANE, AYRES CALDAS LUCIO, S. MARTINS-DUARTE ERICA. Intracellular life of protozoan Toxoplasma gondii: Parasitophorous vacuole establishment and survival strategies. BIOCELL 2023. [DOI: 10.32604/biocell.2023.026629] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/11/2023]
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6
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Dong J, Zhang N, Zhao P, Li J, Cao L, Wang X, Li X, Yang J, Zhang X, Gong P. Disruption of Dense Granular Protein 2 (GRA2) Decreases the Virulence of Neospora caninum. Front Vet Sci 2021; 8:634612. [PMID: 33681332 PMCID: PMC7933011 DOI: 10.3389/fvets.2021.634612] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 01/11/2021] [Indexed: 01/18/2023] Open
Abstract
Neospora caninum causes abortions in cattle and nervous system dysfunction in dogs. Dense granular proteins (GRAs) play important roles in virulence; however, studies on NcGRA functions are limited. In the present study, multiple methods, including site-directed mutagenesis; CRISPR/Cas9 gene editing; Western blotting; quantitative polymerase chain reaction; confocal microscopy; plaque, invasion, egress, and replication assays; animal assays of survival rate and parasite burden; and hematoxylin-eosin staining, were used to characterize the NcGRA2 protein, construct an NcGRA2 gene disruption (ΔNcGRA2) strain, and explore its virulence in vivo and vitro. The results showed that NcGRA2 shared 31.31% homology with TgGRA2 and was colocalized with NcGRA6 at the posterior end of tachyzoites and the intravacuolar network of parasitophorous vacuoles (PVs). Cell fractionation analysis showed that NcGRA2 behaved as a transmembrane and membrane-coupled protein. The ΔNcGRA2 strain was constructed by coelectroporation of the NcGRA2-targeting CRISPR plasmid (pNc-SAG1-Cas9:U6-SgGRA2) and DHFR-TS DNA donor and verified at the protein, genome, and transcriptional levels and by immunofluorescence localization analysis. The in vitro virulence results showed that the ΔNcGRA2 strain displayed smaller plaques, similar invasion and egress abilities, and slower intracellular growth. The in vivo virulence results showed a prolonged survival time, lower parasite burden, and mild histopathological changes. Overall, the present study indicates that NcGRA2, as a dense granular protein, forms the intravacuolar network structure of PVs and weakens N. caninum virulence by slowing proliferation. These data highlight the roles of NcGRA2 and provide a foundation for research on other protein functions in N. caninum.
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Affiliation(s)
- Jingquan Dong
- Key Laboratory of Zoonosis, College of Veterinary Medicine, Jilin University, Changchun, China.,Jiangsu Key Laboratory of Marine Biological Resources and Environment, Jiangsu Key Laboratory of Marine Pharmaceutical Compound Screening, Co-Innovation Center of Jiangsu Marine Bio-industry Technology, Jiangsu Ocean University, Lianyungang, China
| | - Nan Zhang
- Key Laboratory of Zoonosis, College of Veterinary Medicine, Jilin University, Changchun, China
| | - Panpan Zhao
- Key Laboratory of Zoonosis, College of Veterinary Medicine, Jilin University, Changchun, China.,Jiangsu Key Laboratory of Marine Biological Resources and Environment, Jiangsu Key Laboratory of Marine Pharmaceutical Compound Screening, Co-Innovation Center of Jiangsu Marine Bio-industry Technology, Jiangsu Ocean University, Lianyungang, China
| | - Jianhua Li
- Key Laboratory of Zoonosis, College of Veterinary Medicine, Jilin University, Changchun, China
| | - Lili Cao
- Key Laboratory of Zoonosis, College of Veterinary Medicine, Jilin University, Changchun, China.,Department of Parasite, Jilin Academy of Animal Husbandry and Veterinary Medicine, Changchun, China
| | - Xiaocen Wang
- Key Laboratory of Zoonosis, College of Veterinary Medicine, Jilin University, Changchun, China
| | - Xin Li
- Key Laboratory of Zoonosis, College of Veterinary Medicine, Jilin University, Changchun, China
| | - Ju Yang
- Key Laboratory of Zoonosis, College of Veterinary Medicine, Jilin University, Changchun, China
| | - Xichen Zhang
- Key Laboratory of Zoonosis, College of Veterinary Medicine, Jilin University, Changchun, China
| | - Pengtao Gong
- Key Laboratory of Zoonosis, College of Veterinary Medicine, Jilin University, Changchun, China
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7
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Attias M, Teixeira DE, Benchimol M, Vommaro RC, Crepaldi PH, De Souza W. The life-cycle of Toxoplasma gondii reviewed using animations. Parasit Vectors 2020; 13:588. [PMID: 33228743 PMCID: PMC7686686 DOI: 10.1186/s13071-020-04445-z] [Citation(s) in RCA: 95] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Accepted: 10/30/2020] [Indexed: 11/21/2022] Open
Abstract
Toxoplasma gondii is a protozoan parasite that is the causative agent of toxoplasmosis, an infection with high prevalence worldwide. Most of the infected individuals are either asymptomatic or have mild symptoms, but T. gondii can cause severe neurologic damage and even death of the fetus when acquired during pregnancy. It is also a serious condition in immunodeficient patients. The life-cycle of T. gondii is complex, with more than one infective form and several transmission pathways. In two animated videos, we describe the main aspects of this cycle, raising questions about poorly or unknown issues of T. gondii biology. Original plates, based on electron microscope observations, are also available for teachers, students and researchers. The main goal of this review is to provide a source of learning on the fundamental aspects of T. gondii biology to students and teachers contributing for better knowledge and control on this important parasite, and unique cell model. In addition, drawings and videos point to still unclear aspects of T. gondii lytic cycle that may stimulate further studies.![]()
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Affiliation(s)
- Márcia Attias
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil. .,Centro Nacional de Biologia Estrutural e Bioimagem, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
| | | | | | - Rossiane C Vommaro
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Paulo Henrique Crepaldi
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Wanderley De Souza
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.,Centro Nacional de Biologia Estrutural e Bioimagem, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
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8
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Wang Y, Sangaré LO, Paredes-Santos TC, Saeij JPJ. Toxoplasma Mechanisms for Delivery of Proteins and Uptake of Nutrients Across the Host-Pathogen Interface. Annu Rev Microbiol 2020; 74:567-586. [PMID: 32680452 PMCID: PMC9934516 DOI: 10.1146/annurev-micro-011720-122318] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Many intracellular pathogens, including the protozoan parasite Toxoplasma gondii, live inside a vacuole that resides in the host cytosol. Vacuolar residence provides these pathogens with a defined niche for replication and protection from detection by host cytosolic pattern recognition receptors. However, the limiting membrane of the vacuole, which constitutes the host-pathogen interface, is also a barrier for pathogen effectors to reach the host cytosol and for the acquisition of host-derived nutrients. This review provides an update on the specialized secretion and trafficking systems used by Toxoplasma to overcome the barrier of the parasitophorous vacuole membrane and thereby allow the delivery of proteins into the host cell and the acquisition of host-derived nutrients.
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Affiliation(s)
- Yifan Wang
- Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, California 95616, USA; , , ,
| | - Lamba Omar Sangaré
- Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, California 95616, USA; , , ,
| | - Tatiana C. Paredes-Santos
- Department of Pathology, Microbiology & Immunology, School of Veterinary Medicine, University of California, Davis, Davis, California, USA
| | - Jeroen P. J. Saeij
- Department of Pathology, Microbiology & Immunology, School of Veterinary Medicine, University of California, Davis, Davis, California, USA
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9
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Wang JL, Bai MJ, Elsheikha HM, Liang QL, Li TT, Cao XZ, Zhu XQ. Novel roles of dense granule protein 12 (GRA12) in Toxoplasma gondii infection. FASEB J 2020; 34:3165-3178. [PMID: 31908049 DOI: 10.1096/fj.201901416rr] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2019] [Revised: 12/18/2019] [Accepted: 12/19/2019] [Indexed: 01/09/2023]
Abstract
Dense granule protein 12 (GRA12) is implicated in a range of processes related to the establishment of Toxoplasma gondii infection, such as the formation of the intravacuolar network (IVN) within the parasitophorous vacuole (PV). This protein is also thought to be important for T. gondii-host interaction, pathogenesis, and immune evasion, but their exact roles remain unknown. In this study, the contributions of GRA12 to the molecular pathogenesis of T. gondii infection were examined in vitro and in vivo. Deletion of GRA12 in type I RH and type II Pru T. gondii strains did not affect the parasite growth and replication in vitro, however, it caused a significant reduction in the parasite virulence and tissue cyst burden in vivo. T. gondii Δgra12 mutants were more vulnerable to be eliminated by host immunity, without the accumulation of immunity-related GTPase a6 (Irga6) onto the PV membrane. The ultrastructure of IVN in Δgra12 mutants appeared normal, suggesting that GRA12 is not required for biogenesis of the IVN. Combined deletion of GRA12 and ROP18 induced more severe attenuation of virulence compared to single Δgra12 or Δrop18 mutant strains. These data suggest a functional association between GRA12 and ROP18 that is revealed by the severe attenuation of virulence in a double mutant relative to the single individual mutations. Future studies are needed to define the molecular basis of this putative association. Collectively these findings indicate that although GRA12 is not essential for the parasite growth and replication in vitro, it contributes to the virulence and growth of T. gondii in mice.
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Affiliation(s)
- Jin-Lei Wang
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, P.R. China
| | - Meng-Jie Bai
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, P.R. China
| | - Hany M Elsheikha
- Faculty of Medicine and Health Sciences, School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington Campus, Loughborough, UK
| | - Qin-Li Liang
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, P.R. China
| | - Ting-Ting Li
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, P.R. China
| | - Xue-Zhen Cao
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, P.R. China
| | - Xing-Quan Zhu
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, P.R. China
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10
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Hunt A, Russell MRG, Wagener J, Kent R, Carmeille R, Peddie CJ, Collinson L, Heaslip A, Ward GE, Treeck M. Differential requirements for cyclase-associated protein (CAP) in actin-dependent processes of Toxoplasma gondii. eLife 2019; 8:e50598. [PMID: 31577230 PMCID: PMC6785269 DOI: 10.7554/elife.50598] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Accepted: 09/26/2019] [Indexed: 12/26/2022] Open
Abstract
Toxoplasma gondii contains a limited subset of actin binding proteins. Here we show that the putative actin regulator cyclase-associated protein (CAP) is present in two different isoforms and its deletion leads to significant defects in some but not all actin dependent processes. We observe defects in cell-cell communication, daughter cell orientation and the juxtanuclear accumulation of actin, but only modest defects in synchronicity of division and no defect in the replication of the apicoplast. 3D electron microscopy reveals that loss of CAP results in a defect in formation of a normal central residual body, but parasites remain connected within the vacuole. This dissociates synchronicity of division and parasite rosetting and reveals that establishment and maintenance of the residual body may be more complex than previously thought. These results highlight the different spatial requirements for F-actin regulation in Toxoplasma which appear to be achieved by partially overlapping functions of actin regulators.
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Affiliation(s)
- Alex Hunt
- Signalling in Apicomplexan Parasites Laboratory, The Francis Crick InstituteLondonUnited Kingdom
| | | | - Jeanette Wagener
- Signalling in Apicomplexan Parasites Laboratory, The Francis Crick InstituteLondonUnited Kingdom
| | - Robyn Kent
- Department of Microbiology and Molecular GeneticsUniversity of Vermont Larner College of MedicineBurlingtonUnited States
| | - Romain Carmeille
- Department of Molecular and Cell BiologyUniversity of ConnecticutStorrsUnited States
| | - Christopher J Peddie
- Electron Microscopy Science Technology Platform, The Francis Crick InstituteLondonUnited Kingdom
| | - Lucy Collinson
- Electron Microscopy Science Technology Platform, The Francis Crick InstituteLondonUnited Kingdom
| | - Aoife Heaslip
- Department of Molecular and Cell BiologyUniversity of ConnecticutStorrsUnited States
| | - Gary E Ward
- Department of Microbiology and Molecular GeneticsUniversity of Vermont Larner College of MedicineBurlingtonUnited States
| | - Moritz Treeck
- Signalling in Apicomplexan Parasites Laboratory, The Francis Crick InstituteLondonUnited Kingdom
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11
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Translocation of effector proteins into host cells by Toxoplasma gondii. Curr Opin Microbiol 2019; 52:130-138. [PMID: 31446366 DOI: 10.1016/j.mib.2019.07.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 07/19/2019] [Accepted: 07/22/2019] [Indexed: 12/12/2022]
Abstract
The Apicomplexan parasite, Toxoplasma gondii, is an obligate intracellular organism that must co-opt its host cell to survive. To this end, Toxoplasma parasites introduce a suite of effector proteins from two secretory compartments called rhoptries and dense granules into the host cells. Once inside, these effectors extensively modify the host cell to facilitate parasite penetration, replication and persistence. In this review, we summarize the most recent advances in current understanding of effector translocation from Toxoplasma's rhoptry and dense granule organelles into the host cell, with comparisons to Plasmodium spp. for broader context.
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12
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Beraki T, Hu X, Broncel M, Young JC, O'Shaughnessy WJ, Borek D, Treeck M, Reese ML. Divergent kinase regulates membrane ultrastructure of the Toxoplasma parasitophorous vacuole. Proc Natl Acad Sci U S A 2019; 116:6361-6370. [PMID: 30850550 PMCID: PMC6442604 DOI: 10.1073/pnas.1816161116] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Apicomplexan parasites replicate within a protective organelle, called the parasitophorous vacuole (PV). The Toxoplasma gondii PV is filled with a network of tubulated membranes, which are thought to facilitate trafficking of effectors and nutrients. Despite being critical to parasite virulence, there is scant mechanistic understanding of the network's functions. Here, we identify the parasite-secreted kinase WNG1 (With-No-Gly-loop) as a critical regulator of tubular membrane biogenesis. WNG1 family members adopt an atypical protein kinase fold lacking the glycine rich ATP-binding loop that is required for catalysis in canonical kinases. Unexpectedly, we find that WNG1 is an active protein kinase that localizes to the PV lumen and phosphorylates PV-resident proteins, several of which are essential for the formation of a functional intravacuolar network. Moreover, we show that WNG1-dependent phosphorylation of these proteins is required for their membrane association, and thus their ability to tubulate membranes. Consequently, WNG1 knockout parasites have an aberrant PV membrane ultrastructure. Collectively, our results describe a unique family of Toxoplasma kinases and implicate phosphorylation of secreted proteins as a mechanism of regulating PV development during parasite infection.
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Affiliation(s)
- Tsebaot Beraki
- Department of Pharmacology, University of Texas, Southwestern Medical Center, Dallas, TX 75390
| | - Xiaoyu Hu
- Department of Pharmacology, University of Texas, Southwestern Medical Center, Dallas, TX 75390
| | - Malgorzata Broncel
- Signalling in Apicomplexan Parasites Laboratory, The Francis Crick Institute, NW1 1AT London United Kingdom
| | - Joanna C Young
- Signalling in Apicomplexan Parasites Laboratory, The Francis Crick Institute, NW1 1AT London United Kingdom
| | - William J O'Shaughnessy
- Department of Pharmacology, University of Texas, Southwestern Medical Center, Dallas, TX 75390
| | - Dominika Borek
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX 75390
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Moritz Treeck
- Signalling in Apicomplexan Parasites Laboratory, The Francis Crick Institute, NW1 1AT London United Kingdom
| | - Michael L Reese
- Department of Pharmacology, University of Texas, Southwestern Medical Center, Dallas, TX 75390;
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75390
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13
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New advances in scanning microscopy and its application to study parasitic protozoa. Exp Parasitol 2018; 190:10-33. [PMID: 29702111 DOI: 10.1016/j.exppara.2018.04.018] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2017] [Revised: 04/10/2018] [Accepted: 04/23/2018] [Indexed: 12/31/2022]
Abstract
Scanning electron microscopy has been used to observe and study parasitic protozoa for at least 40 years. However, field emission electron sources, as well as improvements in lenses and detectors, brought the resolution power of scanning electron microscopes (SEM) to a new level. Parallel to the refinement of instruments, protocols for preservation of the ultrastructure, immunolabeling, exposure of cytoskeleton and inner structures of parasites and host cells were developed. This review is focused on protozoan parasites of medical and veterinary relevance, e.g., Toxoplasma gondii, Tritrichomonas foetus, Giardia intestinalis, and Trypanosoma cruzi, compilating the main achievements in describing the fine ultrastructure of their surface, cytoskeleton and interaction with host cells. Two new resources, namely, Helium Ion Microscopy (HIM) and Slice and View, using either Focused Ion Beam (FIB) abrasion or Microtome Serial Sectioning (MSS) within the microscope chamber, combined to backscattered electron imaging of fixed (chemically or by quick freezing followed by freeze substitution and resin embedded samples is bringing an exponential amount of valuable information. In HIM there is no need of conductive coating and the depth of field is much higher than in any field emission SEM. As for FIB- and MSS-SEM, high resolution 3-D models of areas and volumes larger than any other technique allows can be obtained. The main results achieved with all these technological tools and some protocols for sample preparation are included in this review. In addition, we included some results obtained with environmental/low vacuum scanning microscopy and cryo-scanning electron microscopy, both promising, but not yet largely employed SEM modalities.
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14
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Affiliation(s)
- Isabelle Coppens
- Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, United States of America
- * E-mail: (IC); (JDR)
| | - Julia D. Romano
- Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, United States of America
- * E-mail: (IC); (JDR)
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15
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Santi-Rocca J, Blanchard N. Membrane trafficking and remodeling at the host-parasite interface. Curr Opin Microbiol 2017; 40:145-151. [PMID: 29175340 DOI: 10.1016/j.mib.2017.11.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Revised: 10/14/2017] [Accepted: 11/13/2017] [Indexed: 11/16/2022]
Abstract
Membrane shape is functionally linked with many cellular processes. The limiting membrane of vacuoles containing Toxoplasma gondii and Plasmodium apicomplexan parasites lies at the host-parasite interface. This membrane comprises intra-vacuolar and extra-vacuolar tubulo-vesicular deformations, which influence host-parasite cross-talk. Here, underscoring specificities and similarities between the T. gondii and Plasmodium contexts, we present recent findings about vacuolar membrane remodeling and its potential roles in parasite fitness and immune recognition. We review in particular the implication of tubulo-vesicular structures in trapping and/or transporting host and parasite components. Understanding how membrane remodeling influences host-pathogen interactions is expected to be critical in the battle against many intracellular pathogens beyond parasites.
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Affiliation(s)
- Julien Santi-Rocca
- Centre de Physiopathologie de Toulouse Purpan (CPTP), INSERM, CNRS, Université de Toulouse, UPS, Toulouse, France
| | - Nicolas Blanchard
- Centre de Physiopathologie de Toulouse Purpan (CPTP), INSERM, CNRS, Université de Toulouse, UPS, Toulouse, France.
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16
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Portes J, Motta C, Azeredo N, Fernandes C, Horn A, De Souza W, DaMatta R, Seabra S. In vitro treatment of Toxoplasma gondii with copper(II) complexes induces apoptosis-like and cellular division alterations. Vet Parasitol 2017; 245:141-152. [DOI: 10.1016/j.vetpar.2017.04.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 03/21/2017] [Accepted: 04/02/2017] [Indexed: 11/17/2022]
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17
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Caldas LA, Attias M, de Souza W. A structural analysis of the natural egress of Toxoplasma gondii. Microbes Infect 2017; 20:57-62. [PMID: 28951315 DOI: 10.1016/j.micinf.2017.09.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Revised: 08/29/2017] [Accepted: 09/11/2017] [Indexed: 01/18/2023]
Abstract
Previous studies have analysed the process of Toxoplasma gondii egress with the aid of inducers, such as calcium ionophores. Although calcium transients have been successful in triggering T. gondii egress, the structural panorama of "natural" and artificial events should match. The present study approaches the natural egress of this parasite using super-resolution and electron microscopy and reveals lytic and non-lytic events of individual egress; this corroborates the use of calcium ionophore as a reliable tool to trigger parasite egress. Altogether, our data suggest that different signalling routes can converge to similar structural aspects in natural and induced egress.
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Affiliation(s)
- Lúcio Ayres Caldas
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Brazil.
| | - Marcia Attias
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Brazil
| | - Wanderley de Souza
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Brazil; Instituto Nacional de Ciência e Tecnologia de Biologia Estrutural e Bioimagem, Rio de Janeiro, Brazil
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18
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Caldas LA, Soares LL, Henrique Seabra S, Attias M, de Souza W. Monitoring of dynamin during the Toxoplasma gondii cell cycle. Pathog Dis 2016; 74:ftw108. [PMID: 27811048 DOI: 10.1093/femspd/ftw108] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 05/29/2016] [Accepted: 10/29/2016] [Indexed: 11/13/2022] Open
Abstract
The obligate intracellular protozoan parasite Toxoplasma gondii actively invades virtually all warm-blooded nucleated cells. This process results in a non-fusogenic vacuole, inside which the parasites replicate continuously until egress signaling is triggered. In this work, we investigated the role of the large GTPase dynamin in the interaction of T. gondii with the host cell by using laser and electron microscopy during three key stages: invasion, development and egress. The detection of dynamin during invasion indicates the occurrence of endocytosis, while T. gondii egress appeared to be independent of dynamin participation. However, the presence of dynamin during T. gondii development suggests that this molecule plays undescribed roles in the tachyzoite's cell cycle.
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Affiliation(s)
- Lucio Ayres Caldas
- Instituto de Biofí-sica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21941-902, Brazil
| | - Leandro Lemgruber Soares
- Instituto Nacional de Metrologia Normalizacao e Qualidade Industrial, Duque de Caxias, RJ 25250-020, Brazil.,Wellcome Trust Centre for Molecular Parasitology, University of Glasgow, 120 University Place Glasgow, Glasgow G12 8QQ, UK
| | - Sergio Henrique Seabra
- Microbiologia, UEZO, Av. Manuel Caldeira de Alvarenga, Rio de Janeiro, RJ 23070-200, Brazil
| | - Marcia Attias
- Instituto de Biofí-sica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21941-902, Brazil
| | - Wanderley de Souza
- Instituto de Biofí-sica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21941-902, Brazil
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19
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Phenotypes Associated with Knockouts of Eight Dense Granule Gene Loci (GRA2-9) in Virulent Toxoplasma gondii. PLoS One 2016; 11:e0159306. [PMID: 27458822 PMCID: PMC4961421 DOI: 10.1371/journal.pone.0159306] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2016] [Accepted: 06/30/2016] [Indexed: 11/19/2022] Open
Abstract
Toxoplasma gondii actively invades host cells and establishes a parasitophorous vacuole (PV) that accumulates many proteins secreted by the dense granules (GRA proteins). To date, at least 23 GRA proteins have been reported, though the function(s) of most of these proteins still remains unknown. We targeted gene knockouts at ten GRA gene loci (GRA1-10) to investigate the cellular roles and essentiality of these classical GRA proteins during acute infection in the virulent type I RH strain. While eight of these genes (GRA2-9) were successfully knocked out, targeted knockouts at the GRA1 and GRA10 loci were not obtained, suggesting these GRA proteins may be essential. As expected, the Δgra2 and Δgra6 knockouts failed to form an intravacuolar network (IVN). Surprisingly, Δgra7 exhibited hyper-formation of the IVN in both normal and lipid-free growth conditions. No morphological alterations were identified in parasite or PV structures in the Δgra3, Δgra4, Δgra5, Δgra8, or Δgra9 knockouts. With the exception of the Δgra3 and Δgra8 knockouts, all of the GRA knockouts exhibited defects in their infection rate in vitro. While the single GRA knockouts did not exhibit reduced replication rates in vitro, replication rate defects were observed in three double GRA knockout strains (Δgra4Δgra6, Δgra3Δgra5 and Δgra3Δgra7). However, the virulence of single or double GRA knockout strains in CD1 mice was not affected. Collectively, our results suggest that while the eight individual GRA proteins investigated in this study (GRA2-9) are not essential, several GRA proteins may provide redundant and potentially important functions during acute infection.
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20
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Abstract
Invasive stages of apicomplexan parasites require a host cell to survive, proliferate and advance to the next life cycle stage. Once invasion is achieved, apicomplexans interact closely with the host cell cytoskeleton, but in many cases the different species have evolved distinct mechanisms and pathways to modulate the structural organization of cytoskeletal filaments. The host cell cytoskeleton is a complex network, largely, but not exclusively, composed of microtubules, actin microfilaments and intermediate filaments, all of which are modulated by associated proteins, and it is involved in diverse functions including maintenance of cell morphology and mechanical support, migration, signal transduction, nutrient uptake, membrane and organelle trafficking and cell division. The ability of apicomplexans to modulate the cytoskeleton to their own advantage is clearly beneficial. We here review different aspects of the interactions of apicomplexans with the three main cytoskeletal filament types, provide information on the currently known parasite effector proteins and respective host cell targets involved, and how these interactions modulate the host cell physiology. Some of these findings could provide novel targets that could be exploited for the development of preventive and/or therapeutic strategies.
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21
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Rivera Fernández N, Mondragón Castelán M, González Pozos S, Ramírez Flores CJ, Mondragón González R, Gómez de León CT, Castro Elizalde KN, Marrero Ponce Y, Arán VJ, Martins Alho MA, Mondragón Flores R. A new type of quinoxalinone derivatives affects viability, invasion, and intracellular growth of Toxoplasma gondii tachyzoites in vitro. Parasitol Res 2016; 115:2081-96. [PMID: 26888289 DOI: 10.1007/s00436-016-4953-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Accepted: 02/04/2016] [Indexed: 12/11/2022]
Abstract
Quinoxalinone derivatives, identified as VAM2 compounds (7-nitroquinoxalin-2-ones), were evaluated against Toxoplasma gondii tachyzoites of the RH strain. The VAM2 compounds were previously synthesized based on the design obtained from an in silico prediction with the software TOMOCOMD-CARDD. From the ten VAM2 drugs tested, several showed a deleterious effect on tachyzoites. However, VAM2-2 showed the highest toxoplasmicidal activity generating a remarkable decrease in tachyzoite viability (in about 91 %) and a minimal alteration in the host cell. An evident inhibition of host cell invasion by tachyzoites previously treated with VAM2-2 was observed in a dose-dependent manner. In addition, remarkable alterations were observed in the pellicle parasite, such as swelling, roughness, and blebbing. Toxoplasma motility was inhibited, and subpellicular cytoskeleton integrity was altered, inducing a release of its components to the soluble fraction. VAM2-2 showed a clear and specific deleterious effect on tachyzoites viability, structural integrity, and invasive capabilities with limited effects in host cells morphology and viability. VAM2-2 minimum inhibitory concentration (MIC50) was determined as 3.3 μM ± 1.8. Effects of quinoxalinone derivatives on T. gondii provide the basis for a future therapeutical alternative in the treatment of toxoplasmosis.
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Affiliation(s)
- Norma Rivera Fernández
- Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México, Coyoacán 04510, DF, México
- Departamento de Bioquímica, Centro de Investigación y de Estudios Avanzados del IPN (CINVESTAV), Avenida IPN No 2508 Delegación Gustavo A Madero, 07360, DF, México
| | - Mónica Mondragón Castelán
- Departamento de Bioquímica, Centro de Investigación y de Estudios Avanzados del IPN (CINVESTAV), Avenida IPN No 2508 Delegación Gustavo A Madero, 07360, DF, México
| | | | - Carlos J Ramírez Flores
- Departamento de Bioquímica, Centro de Investigación y de Estudios Avanzados del IPN (CINVESTAV), Avenida IPN No 2508 Delegación Gustavo A Madero, 07360, DF, México
| | | | - Carmen T Gómez de León
- Departamento de Bioquímica, Centro de Investigación y de Estudios Avanzados del IPN (CINVESTAV), Avenida IPN No 2508 Delegación Gustavo A Madero, 07360, DF, México
| | - Kitzia N Castro Elizalde
- Departamento de Bioquímica, Centro de Investigación y de Estudios Avanzados del IPN (CINVESTAV), Avenida IPN No 2508 Delegación Gustavo A Madero, 07360, DF, México
| | - Yovani Marrero Ponce
- Edificio de Especialidades Médicas, Hospital de los Valles, Colegio de Ciencias de la Salud, Universidad de San Francisco de Quito, Av. Interoceánica Km 12 1/2 Cumbayá, Quito, Ecuador
| | - Vicente J Arán
- Instituto de Química Médica, CSIC, c/ Juan de la Cierva 3, 28006, Madrid, España
| | - Miriam A Martins Alho
- Instituto de Química Médica, CSIC, c/ Juan de la Cierva 3, 28006, Madrid, España
- Centro de Investigaciones en Hidratos de Carbono (CIHIDECAR-CONICET), Departamento de Química Orgánica, FCEN y LabMOr - INTECIN, FI, UBA, Paseo Colón 850, 5to. Piso, CP C1063ACV, Buenos Aires, Argentina
| | - Ricardo Mondragón Flores
- Departamento de Bioquímica, Centro de Investigación y de Estudios Avanzados del IPN (CINVESTAV), Avenida IPN No 2508 Delegación Gustavo A Madero, 07360, DF, México.
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22
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Portes JA, Souza TG, dos Santos TAT, da Silva LLR, Ribeiro TP, Pereira MD, Horn A, Fernandes C, DaMatta RA, de Souza W, Seabra SH. Reduction of Toxoplasma gondii Development Due to Inhibition of Parasite Antioxidant Enzymes by a Dinuclear Iron(III) Compound. Antimicrob Agents Chemother 2015; 59:7374-86. [PMID: 26392498 PMCID: PMC4649245 DOI: 10.1128/aac.00057-15] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Accepted: 07/22/2015] [Indexed: 11/20/2022] Open
Abstract
Toxoplasma gondii, the causative agent of toxoplasmosis, is an obligate intracellular protozoan that can infect a wide range of vertebrate cells. Here, we describe the cytotoxic effects of the dinuclear iron compound [Fe(HPCINOL)(SO4)]2-μ-oxo, in which HPCINOL is the ligand 1-(bis-pyridin-2-ylmethyl-amino)-3-chloropropan-2-ol, on T. gondii infecting LLC-MK2 host cells. This compound was not toxic to LLC-MK2 cells at concentrations of up to 200 μM but was very active against the parasite, with a 50% inhibitory concentration (IC50) of 3.6 μM after 48 h of treatment. Cyst formation was observed after treatment, as indicated by the appearance of a cyst wall, Dolichos biflorus lectin staining, and scanning and transmission electron microscopy characteristics. Ultrastructural changes were also seen in T. gondii, including membrane blebs and clefts in the cytoplasm, with inclusions similar to amylopectin granules, which are typically found in bradyzoites. An analysis of the cell death pathways in the parasite revealed that the compound caused a combination of apoptosis and autophagy. Fluorescence assays demonstrated that the redox environment in the LLC-MK2 cells becomes oxidant in the presence of the iron compound. Furthermore, a reduction in superoxide dismutase and catalase activities in the treated parasites and the presence of reactive oxygen species within the parasitophorous vacuoles were observed, indicating an impaired protozoan response against these radicals. These findings suggest that this compound disturbs the redox equilibrium of T. gondii, inducing cystogenesis and parasite death.
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Affiliation(s)
- J A Portes
- Laboratório de Tecnologia em Cultura de Células, Centro Universitário Estadual da Zona Oeste (UEZO), Rio de Janeiro, RJ, Brazil Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ, Brazil
| | - T G Souza
- Laboratório de Tecnologia em Cultura de Células, Centro Universitário Estadual da Zona Oeste (UEZO), Rio de Janeiro, RJ, Brazil
| | - T A T dos Santos
- Laboratório de Tecnologia em Cultura de Células, Centro Universitário Estadual da Zona Oeste (UEZO), Rio de Janeiro, RJ, Brazil Laboratório de Biologia Celular e Tecidual, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense Darcy Ribeiro (UENF), Campos dos Goytacazes, Rio de Janeiro, RJ, Brazil
| | - L L R da Silva
- Laboratório de Biologia Celular e Tecidual, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense Darcy Ribeiro (UENF), Campos dos Goytacazes, Rio de Janeiro, RJ, Brazil
| | - T P Ribeiro
- Laboratório de Citotoxicidade e Genotoxicidade, Departamento de Bioquímica, Instituto de Química, UFRJ, Rio de Janeiro, RJ, Brazil
| | - M D Pereira
- Laboratório de Citotoxicidade e Genotoxicidade, Departamento de Bioquímica, Instituto de Química, UFRJ, Rio de Janeiro, RJ, Brazil
| | - A Horn
- Laboratório de Ciências Químicas, Centro de Ciência e Tecnologia, UENF, Campos dos Goytacazes, Rio de Janeiro, RJ, Brazil
| | - C Fernandes
- Laboratório de Ciências Químicas, Centro de Ciência e Tecnologia, UENF, Campos dos Goytacazes, Rio de Janeiro, RJ, Brazil
| | - R A DaMatta
- Laboratório de Biologia Celular e Tecidual, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense Darcy Ribeiro (UENF), Campos dos Goytacazes, Rio de Janeiro, RJ, Brazil
| | - W de Souza
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ, Brazil Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagem (INBEB) and Centro Nacional de Biologia Estrutural e Bioimagem (CENABIO), UFRJ, Rio de Janeiro, RJ, Brazil Instituto Nacional de Metrologia, Qualidade e Tecnologia (Inmetro), Duque de Caxias, RJ, Brazil
| | - S H Seabra
- Laboratório de Tecnologia em Cultura de Células, Centro Universitário Estadual da Zona Oeste (UEZO), Rio de Janeiro, RJ, Brazil
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23
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Lopez J, Bittame A, Massera C, Vasseur V, Effantin G, Valat A, Buaillon C, Allart S, Fox BA, Rommereim LM, Bzik DJ, Schoehn G, Weissenhorn W, Dubremetz JF, Gagnon J, Mercier C, Cesbron-Delauw MF, Blanchard N. Intravacuolar Membranes Regulate CD8 T Cell Recognition of Membrane-Bound Toxoplasma gondii Protective Antigen. Cell Rep 2015; 13:2273-86. [PMID: 26628378 DOI: 10.1016/j.celrep.2015.11.001] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Revised: 08/11/2015] [Accepted: 10/30/2015] [Indexed: 11/20/2022] Open
Abstract
Apicomplexa parasites such as Toxoplasma gondii target effectors to and across the boundary of their parasitophorous vacuole (PV), resulting in host cell subversion and potential presentation by MHC class I molecules for CD8 T cell recognition. The host-parasite interface comprises the PV limiting membrane and a highly curved, membranous intravacuolar network (IVN) of uncertain function. Here, using a cell-free minimal system, we dissect how membrane tubules are shaped by the parasite effectors GRA2 and GRA6. We show that membrane association regulates access of the GRA6 protective antigen to the MHC I pathway in infected cells. Although insertion of GRA6 in the PV membrane is key for immunogenicity, association of GRA6 with the IVN limits presentation and curtails GRA6-specific CD8 responses in mice. Thus, membrane deformations of the PV regulate access of antigens to the MHC class I pathway, and the IVN may play a role in immune modulation.
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Affiliation(s)
- Jodie Lopez
- INSERM, U1043, Toulouse 31300, France; CNRS, UMR 5282, Toulouse 31300, France; Centre de Physiopathologie de Toulouse Purpan (CPTP), Université de Toulouse, UPS, Toulouse 31300, France
| | - Amina Bittame
- CNRS, UMR 5163, Grenoble 38000, France; Laboratoire Adaptation et Pathogénie des Microorganismes (LAPM), Université Grenoble Alpes, Grenoble 38000, France
| | - Céline Massera
- CNRS, UMR 5163, Grenoble 38000, France; Laboratoire Adaptation et Pathogénie des Microorganismes (LAPM), Université Grenoble Alpes, Grenoble 38000, France
| | - Virginie Vasseur
- INSERM, U1043, Toulouse 31300, France; CNRS, UMR 5282, Toulouse 31300, France; Centre de Physiopathologie de Toulouse Purpan (CPTP), Université de Toulouse, UPS, Toulouse 31300, France
| | - Grégory Effantin
- Institut de Biologie Structurale (IBS), Université Grenoble Alpes, Grenoble 38044, France; CNRS, IBS, Grenoble 38044, France; CEA, IBS, Grenoble 38044, France; CNRS, Unit for Virus Host-Cell Interactions (UVHCI), Grenoble 38042, France
| | - Anne Valat
- CNRS, UMR 5163, Grenoble 38000, France; Laboratoire Adaptation et Pathogénie des Microorganismes (LAPM), Université Grenoble Alpes, Grenoble 38000, France
| | - Célia Buaillon
- INSERM, U1043, Toulouse 31300, France; CNRS, UMR 5282, Toulouse 31300, France; Centre de Physiopathologie de Toulouse Purpan (CPTP), Université de Toulouse, UPS, Toulouse 31300, France
| | - Sophie Allart
- INSERM, U1043, Toulouse 31300, France; CNRS, UMR 5282, Toulouse 31300, France; Centre de Physiopathologie de Toulouse Purpan (CPTP), Université de Toulouse, UPS, Toulouse 31300, France
| | - Barbara A Fox
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Lebanon, NH 03756, USA
| | - Leah M Rommereim
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Lebanon, NH 03756, USA
| | - David J Bzik
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Lebanon, NH 03756, USA
| | - Guy Schoehn
- Institut de Biologie Structurale (IBS), Université Grenoble Alpes, Grenoble 38044, France; CNRS, IBS, Grenoble 38044, France; CEA, IBS, Grenoble 38044, France; CNRS, Unit for Virus Host-Cell Interactions (UVHCI), Grenoble 38042, France
| | - Winfried Weissenhorn
- Institut de Biologie Structurale (IBS), Université Grenoble Alpes, Grenoble 38044, France; CNRS, IBS, Grenoble 38044, France; CEA, IBS, Grenoble 38044, France; CNRS, Unit for Virus Host-Cell Interactions (UVHCI), Grenoble 38042, France
| | | | - Jean Gagnon
- CNRS, UMR 5163, Grenoble 38000, France; Laboratoire Adaptation et Pathogénie des Microorganismes (LAPM), Université Grenoble Alpes, Grenoble 38000, France
| | - Corinne Mercier
- CNRS, UMR 5163, Grenoble 38000, France; Laboratoire Adaptation et Pathogénie des Microorganismes (LAPM), Université Grenoble Alpes, Grenoble 38000, France
| | - Marie-France Cesbron-Delauw
- CNRS, UMR 5163, Grenoble 38000, France; Laboratoire Adaptation et Pathogénie des Microorganismes (LAPM), Université Grenoble Alpes, Grenoble 38000, France
| | - Nicolas Blanchard
- INSERM, U1043, Toulouse 31300, France; CNRS, UMR 5282, Toulouse 31300, France; Centre de Physiopathologie de Toulouse Purpan (CPTP), Université de Toulouse, UPS, Toulouse 31300, France.
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24
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da Silva LLR, Portes JDA, de Araújo MH, Silva JLS, Rennó MN, Netto CD, da Silva AJM, Costa PRR, De Souza W, Seabra SH, DaMatta RA. Further evidence that naphthoquinone inhibits Toxoplasma gondii growth in vitro. Parasitol Int 2015; 64:622-31. [PMID: 26335616 DOI: 10.1016/j.parint.2015.08.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2014] [Revised: 08/25/2015] [Accepted: 08/28/2015] [Indexed: 11/30/2022]
Abstract
Toxoplasmosis is a widely disseminated disease caused by Toxoplasma gondii, an intracellular protozoan parasite. Standard treatment causes many side effects, such as depletion of bone marrow cells, skin rashes and gastrointestinal implications. Therefore, it is necessary to find chemotherapeutic alternatives for the treatment of this disease. It was shown that a naphthoquinone derivative compound is active against T. gondii, RH strain, with an IC50 around 2.5 μM. Here, three different naphthoquinone derivative compounds with activity against leukemia cells and breast carcinoma cell were tested against T. gondii (RH strain) infected LLC-MK2 cell line. All the compounds were able to inhibit parasite growth in vitro, but one of them showed an IC50 activity below 1 μM after 48 h of treatment. The compounds showed low toxicity to the host cell. In addition, these compounds were able to induce tachyzoite-bradyzoite conversion confirmed by morphological changes, Dolichus biflorus lectin cyst wall labeling and characterization of amylopectin granules in the parasites by electron microscopy analysis using the Thierry technique. Furthermore, the compounds induced alterations on the ultrastructure of the parasite. Taken together, our results point to the naphthoquinone derivative (LQB 151) as a potential compound for the development of new drugs for the treatment of toxoplasmosis.
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Affiliation(s)
- Luciana Lemos Rangel da Silva
- Laboratório de Biologia Celular e Tecidual, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense Darcy Ribeiro, Campos dos Goytacazes, RJ, 28013-602, Brazil
| | - Juliana de Araujo Portes
- Laboratório de Tecnologia em Cultura de Células, Centro Universitário Estadual da Zona Oeste, Campo Grande, Rio de Janeiro, RJ, 23070-200, Brazil
| | - Marlon Heggdorne de Araújo
- Laboratório de Produtos Bioativos, Universidade Federal do Rio de Janeiro, Campus Macaé Professor Aloísio Teixeira, Macaé, RJ, 27930-560, Brazil
| | - Jéssica Lays Sant'ana Silva
- Laboratório de Química, Universidade Federal do Rio de Janeiro, Campus Macaé Professor Aloísio Teixeira, Macaé, RJ, 27930-560, Brazil
| | - Magdalena Nascimento Rennó
- Laboratório de Modelagem Molecular e Pesquisa em Ciências Farmacêuticas, Universidade Federal do Rio de Janeiro, Campus Macaé Professor Aloísio Teixeira, Macaé, RJ, 27910-970, Brazil
| | - Chaquip Daher Netto
- Laboratório de Química, Universidade Federal do Rio de Janeiro, Campus Macaé Professor Aloísio Teixeira, Macaé, RJ, 27930-560, Brazil
| | - Alcides José Monteiro da Silva
- Laboratório de Química Bioorgânica, Instituto de Pesquisas de Produtos Naturais, Centro de Ciências da Saúde, Bloco H, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, 21941-590, Brazil
| | - Paulo Roberto Ribeiro Costa
- Laboratório de Química Bioorgânica, Instituto de Pesquisas de Produtos Naturais, Centro de Ciências da Saúde, Bloco H, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, 21941-590, Brazil
| | - Wanderley De Souza
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, 21491-590, Brazil; Instituto Nacional de Metrologia, Qualidade Industrial e Tecnologia-Inmetro, Duque de Caxias, RJ, 20261-232, Brazil
| | - Sergio Henrique Seabra
- Laboratório de Tecnologia em Cultura de Células, Centro Universitário Estadual da Zona Oeste, Campo Grande, Rio de Janeiro, RJ, 23070-200, Brazil
| | - Renato Augusto DaMatta
- Laboratório de Biologia Celular e Tecidual, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense Darcy Ribeiro, Campos dos Goytacazes, RJ, 28013-602, Brazil.
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Moreira-Souza ACA, Marinho Y, Correa G, Santoro GF, Coutinho CMLM, Vommaro RC, Coutinho-Silva R. Pyrimidinergic Receptor Activation Controls Toxoplasma gondii Infection in Macrophages. PLoS One 2015; 10:e0133502. [PMID: 26192447 PMCID: PMC4507979 DOI: 10.1371/journal.pone.0133502] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Accepted: 06/29/2015] [Indexed: 12/20/2022] Open
Abstract
Infection by the protozoan parasite Toxoplasma gondii is highly prevalent worldwide and may have serious clinical manifestations in immunocompromised patients. T. gondii is an obligate intracellular parasite that infects almost any cell type in mammalian hosts, including immune cells. The immune cells express purinergic P2 receptors in their membrane--subdivided into P2Y and P2X subfamilies--whose activation is important for infection control. Here, we examined the effect of treatment with UTP and UDP in mouse peritoneal macrophages infected with T. gondii tachyzoites. Treatment with these nucleotides reduced parasitic load by 90%, but did not increase the levels of the inflammatory mediators NO and ROS, nor did it modulate host cell death by apoptosis or necrosis. On the other hand, UTP and UDP treatments induced early egress of tachyzoites from infected macrophages, in a Ca2+-dependent manner, as shown by scanning electron microscopy analysis, and videomicroscopy. In subsequent infections, prematurely egressed parasites had reduced infectivity, and could neither replicate nor inhibit the fusion of lysosomes to the parasitophorous vacuole. The use of selective agonists and antagonists of the receptor subtypes P2Y2 and P2Y4 and P2Y6 showed that premature parasite egress may be mediated by the activation of these receptor subtypes. Our results suggest that the activity of P2Y host cell receptors controls T. gondii infection in macrophages, highlighting the importance of pyrimidinergic signaling for innate immune system response against infection. Finally the P2Y receptors should be considered as new target for the development of drugs against T. gondii infection.
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MESH Headings
- Animals
- Apoptosis/drug effects
- Cells, Cultured
- Female
- Host-Parasite Interactions/drug effects
- Macrophages/metabolism
- Macrophages/parasitology
- Macrophages/ultrastructure
- Macrophages, Peritoneal/metabolism
- Macrophages, Peritoneal/parasitology
- Macrophages, Peritoneal/ultrastructure
- Male
- Mice, Inbred BALB C
- Mice, Inbred C57BL
- Microscopy, Electron, Scanning
- Microscopy, Electron, Transmission
- Microscopy, Fluorescence
- Nitric Oxide/metabolism
- Purinergic P2Y Receptor Agonists/pharmacology
- Purinergic P2Y Receptor Antagonists/pharmacology
- Reactive Oxygen Species/metabolism
- Receptors, Purinergic P2Y/metabolism
- Suramin/pharmacology
- Toxoplasma/physiology
- Uridine Diphosphate/pharmacology
- Uridine Triphosphate/pharmacology
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Affiliation(s)
- Aline Cristina Abreu Moreira-Souza
- Laboratório de Imunofisiologia, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, 21941–902, Brazil
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, 21941–902, Brazil
- Instituto Nacional de Ciência e Tecnologia para Pesquisa Translacional em Saúde e Ambiente na Região Amazônica (INPeTAm/UFRJ), Rio de Janeiro, RJ, 21941–902, Brazil
| | - Ygor Marinho
- Laboratório de Imunofisiologia, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, 21941–902, Brazil
- Instituto Nacional de Ciência e Tecnologia para Pesquisa Translacional em Saúde e Ambiente na Região Amazônica (INPeTAm/UFRJ), Rio de Janeiro, RJ, 21941–902, Brazil
| | - Gladys Correa
- Laboratório de Imunofisiologia, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, 21941–902, Brazil
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, 21941–902, Brazil
- Instituto Nacional de Ciência e Tecnologia para Pesquisa Translacional em Saúde e Ambiente na Região Amazônica (INPeTAm/UFRJ), Rio de Janeiro, RJ, 21941–902, Brazil
| | - Giani França Santoro
- Laboratório de Imunofisiologia, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, 21941–902, Brazil
- Laboratório de Inovações, Terapias, Ensino e Bioprodutos (LITEB), Instituto Oswaldo Cruz, FIOCRUZ, Rio de Janeiro, RJ, 21.040–900, Brazil
- Instituto Nacional de Ciência e Tecnologia para Pesquisa Translacional em Saúde e Ambiente na Região Amazônica (INPeTAm/UFRJ), Rio de Janeiro, RJ, 21941–902, Brazil
| | - Claudia Mara Lara Melo Coutinho
- Laboratório de Inovações, Terapias, Ensino e Bioprodutos (LITEB), Instituto Oswaldo Cruz, FIOCRUZ, Rio de Janeiro, RJ, 21.040–900, Brazil
- Instituto de Biologia, Universidade Federal Fluminense, Niterói, RJ, 24020–140, Brazil
| | - Rossiane Claudia Vommaro
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, 21941–902, Brazil
| | - Robson Coutinho-Silva
- Laboratório de Imunofisiologia, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, 21941–902, Brazil
- Instituto Nacional de Ciência e Tecnologia para Pesquisa Translacional em Saúde e Ambiente na Região Amazônica (INPeTAm/UFRJ), Rio de Janeiro, RJ, 21941–902, Brazil
- * E-mail:
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de Souza W, Attias M. New views of the Toxoplasma gondii parasitophorous vacuole as revealed by Helium Ion Microscopy (HIM). J Struct Biol 2015; 191:76-85. [PMID: 26004092 DOI: 10.1016/j.jsb.2015.05.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Revised: 05/13/2015] [Accepted: 05/14/2015] [Indexed: 11/27/2022]
Abstract
The Helium Ion Microscope (HIM) is a new technology that uses a highly focused helium ion beam to scan and interact with the sample, which is not coated. The images have resolution and depth of field superior to field emission scanning electron microscopes. In this paper, we used HIM to study LLC-MK2 cells infected with Toxoplasma gondii. These samples were chemically fixed and, after critical point drying, were scraped with adhesive tape to expose the inner structure of the cell and parasitophorous vacuoles. We confirmed some of the previous findings made by field emission-scanning electron microscopy and showed that the surface of the parasite is rich in structures suggestive of secretion, that the nanotubules of the intravacuolar network (IVN) are not always straight, and that bifurcations are less frequent than previously thought. Fusion of the tubules with the parasite membrane or the parasitophorous vacuole membrane (PVM) was also infrequent. Tiny adhesive links were observed for the first time connecting the IVN tubules. The PVM showed openings of various sizes that even allowed the observation of endoplasmic reticulum membranes in the cytoplasm of the host cell. These findings are discussed in relation to current knowledge on the cell biology of T. gondii.
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Affiliation(s)
- Wanderley de Souza
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Centro de Ciências da Saúde, Bloco G, Ilha do Fundão, 21941-902 Rio de Janeiro, RJ, Brazil; Instituto Nacional de Biologia Estrutural e Biomagem-INBEB, and Centro Nacional de Biologia Estrutural e Biomagem-CENABIO, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil; Instituto Nacional de Metrologia, Qualidade e Tecnologia-INMETRO, Duque de Caxias, RJ, Brazil
| | - Marcia Attias
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Centro de Ciências da Saúde, Bloco G, Ilha do Fundão, 21941-902 Rio de Janeiro, RJ, Brazil; Instituto Nacional de Biologia Estrutural e Biomagem-INBEB, and Centro Nacional de Biologia Estrutural e Biomagem-CENABIO, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
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Toxoplasma gondii: biochemical and biophysical characterization of recombinant soluble dense granule proteins GRA2 and GRA6. Biochem Biophys Res Commun 2015; 459:107-12. [PMID: 25712518 DOI: 10.1016/j.bbrc.2015.02.078] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Accepted: 02/15/2015] [Indexed: 11/23/2022]
Abstract
The most prominent structural feature of the parasitophorous vacuole (PV) in which the intracellular parasite Toxoplasma gondii proliferates is a membranous nanotubular network (MNN), which interconnects the parasites and the PV membrane. The MNN function remains unclear. The GRA2 and GRA6 proteins secreted from the parasite dense granules into the PV have been implicated in the MNN biogenesis. Amphipathic alpha-helices (AAHs) predicted in GRA2 and an alpha-helical hydrophobic domain predicted in GRA6 have been proposed to be responsible for their membrane association, thereby potentially molding the MMN in its structure. Here we report an analysis of the recombinant proteins (expressed in detergent-free conditions) by circular dichroism, which showed that full length GRA2 displays an alpha-helical secondary structure while recombinant GRA6 and GRA2 truncated of its AAHs are mainly random coiled. Dynamic light scattering and transmission electron microscopy showed that recombinant GRA6 and truncated GRA2 constitute a homogenous population of small particles (6-8 nm in diameter) while recombinant GRA2 corresponds to 2 populations of particles (∼8-15 nm and up to 40 nm in diameter, respectively). The unusual properties of GRA2 due to its AAHs are discussed.
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28
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Hehl AB, Basso WU, Lippuner C, Ramakrishnan C, Okoniewski M, Walker RA, Grigg ME, Smith NC, Deplazes P. Asexual expansion of Toxoplasma gondii merozoites is distinct from tachyzoites and entails expression of non-overlapping gene families to attach, invade, and replicate within feline enterocytes. BMC Genomics 2015; 16:66. [PMID: 25757795 PMCID: PMC4340605 DOI: 10.1186/s12864-015-1225-x] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Accepted: 01/07/2015] [Indexed: 12/21/2022] Open
Abstract
Background The apicomplexan parasite Toxoplasma gondii is cosmopolitan in nature, largely as a result of its highly flexible life cycle. Felids are its only definitive hosts and a wide range of mammals and birds serve as intermediate hosts. The latent bradyzoite stage is orally infectious in all warm-blooded vertebrates and establishes chronic, transmissible infections. When bradyzoites are ingested by felids, they transform into merozoites in enterocytes and expand asexually as part of their coccidian life cycle. In all other intermediate hosts, however, bradyzoites differentiate exclusively to tachyzoites, and disseminate extraintestinally to many cell types. Both merozoites and tachyzoites undergo rapid asexual population expansion, yet possess different effector fates with respect to the cells and tissues they develop in and the subsequent stages they differentiate into. Results To determine whether merozoites utilize distinct suites of genes to attach, invade, and replicate within feline enterocytes, we performed comparative transcriptional profiling on purified tachyzoites and merozoites. We used high-throughput RNA-Seq to compare the merozoite and tachyzoite transcriptomes. 8323 genes were annotated with sequence reads across the two asexually replicating stages of the parasite life cycle. Metabolism was similar between the two replicating stages. However, significant stage-specific expression differences were measured, with 312 transcripts exclusive to merozoites versus 453 exclusive to tachyzoites. Genes coding for 177 predicted secreted proteins and 64 membrane- associated proteins were annotated as merozoite-specific. The vast majority of known dense-granule (GRA), microneme (MIC), and rhoptry (ROP) genes were not expressed in merozoites. In contrast, a large set of surface proteins (SRS) was expressed exclusively in merozoites. Conclusions The distinct expression profiles of merozoites and tachyzoites reveal significant additional complexity within the T. gondii life cycle, demonstrating that merozoites are distinct asexual dividing stages which are uniquely adapted to their niche and biological purpose. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-1225-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Adrian B Hehl
- Institute of Parasitology-University of Zurich, Winterthurerstrasse 266a, Zürich, 8057, Switzerland.
| | - Walter U Basso
- Institute of Parasitology-University of Zurich, Winterthurerstrasse 266a, Zürich, 8057, Switzerland.
| | - Christoph Lippuner
- Institute of Parasitology-University of Zurich, Winterthurerstrasse 266a, Zürich, 8057, Switzerland. .,Current address: Department of Anaesthesiology and Pain Medicine, Inselspital, University of Bern, Freiburgstrasse, Bern, 3010, Switzerland.
| | - Chandra Ramakrishnan
- Institute of Parasitology-University of Zurich, Winterthurerstrasse 266a, Zürich, 8057, Switzerland.
| | - Michal Okoniewski
- Functional Genomics Center Zurich, Winterthurerstrasse 190, Zürich, 8057, Switzerland.
| | - Robert A Walker
- Institute of Parasitology-University of Zurich, Winterthurerstrasse 266a, Zürich, 8057, Switzerland. .,Queensland Tropical Health Alliance Research Laboratory, Faculty of Medicine, Health and Molecular Sciences, James Cook University, Cairns Campus, McGregor Road, Smithfield, QLD, 4878, Australia.
| | - Michael E Grigg
- Molecular Parasitology Section, Laboratory of Parasitic Diseases, NIAID, NIH, Bethesda, Maryland, USA.
| | - Nicholas C Smith
- Queensland Tropical Health Alliance Research Laboratory, Faculty of Medicine, Health and Molecular Sciences, James Cook University, Cairns Campus, McGregor Road, Smithfield, QLD, 4878, Australia.
| | - Peter Deplazes
- Institute of Parasitology-University of Zurich, Winterthurerstrasse 266a, Zürich, 8057, Switzerland.
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Abstract
The protozoan parasite Toxoplasma gondii resides within a nonfusogenic vacuole during intracellular replication. Although the limiting membrane of this vacuole provides a protective barrier to acidification and degradation by lysosomal hydrolases, it also physically segregates the parasite from the host cytosol. Accordingly, it has been suggested that T. gondii acquires material from the host via membrane channels or transporters. The ability of the parasite to internalize macromolecules via endocytosis during intracellular replication has not been tested. Here, we show that Toxoplasma ingests host cytosolic proteins and digests them using cathepsin L and other proteases within its endolysosomal system. Ingestion was reduced in mutant parasites lacking an intravacuolar network of tubular membranes, implicating this apparatus as a possible conduit for trafficking to the parasite. Genetic ablation of proteins involved in the pathway is associated with diminished parasite replication and virulence attenuation. We show that both virulent type I and avirulent type II strain parasites ingest and digest host-derived protein, indicating that the pathway is not restricted to highly virulent strains. The findings provide the first definitive evidence that T. gondii internalizes proteins from the host during intracellular residence and suggest that protein digestion within the endolysosomal system of the parasite contributes to toxoplasmosis. Toxoplasma gondii causes significant disease in individuals with weak immune systems. Treatment options for this infection have drawbacks, creating a need to understand how this parasite survives within the cells it infects as a prelude to interrupting its survival strategies. This study reveals that T. gondii internalizes proteins from the cytoplasm of the cells it infects and degrades such proteins within a digestive compartment within the parasite. Disruption of proteins involved in the pathway reduced parasite replication and lessened disease severity. The identification of a novel parasite ingestion pathway opens opportunities to interfere with this process and improve the outcome of infection.
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30
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An historical perspective on how advances in microscopic imaging contributed to understanding the Leishmania Spp. and Trypanosoma cruzi host-parasite relationship. BIOMED RESEARCH INTERNATIONAL 2014; 2014:565291. [PMID: 24877115 PMCID: PMC4022312 DOI: 10.1155/2014/565291] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Accepted: 01/10/2014] [Indexed: 12/15/2022]
Abstract
The literature has identified complex aspects of intracellular host-parasite relationships, which require systematic, nonreductionist approaches and spatial/temporal information. Increasing and integrating temporal and spatial dimensions in host cell imaging have contributed to elucidating several conceptual gaps in the biology of intracellular parasites. To access and investigate complex and emergent dynamic events, it is mandatory to follow them in the context of living cells and organs, constructing scientific images with integrated high quality spatiotemporal data. This review discusses examples of how advances in microscopy have challenged established conceptual models of the intracellular life cycles of Leishmania spp. and Trypanosoma cruzi protozoan parasites.
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31
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Caldas LA, Seabra SH, Attias M, de Souza W. The effect of kinase, actin, myosin and dynamin inhibitors on host cell egress by Toxoplasma gondii. Parasitol Int 2013; 62:475-82. [DOI: 10.1016/j.parint.2013.04.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2012] [Revised: 03/26/2013] [Accepted: 04/18/2013] [Indexed: 12/21/2022]
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32
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Dynamics and 3D organization of secretory organelles of Toxoplasma gondii. J Struct Biol 2012; 177:420-30. [DOI: 10.1016/j.jsb.2011.11.028] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2011] [Revised: 11/21/2011] [Accepted: 11/28/2011] [Indexed: 11/23/2022]
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Contribution of the residual body in the spatial organization of Toxoplasma gondii tachyzoites within the parasitophorous vacuole. J Biomed Biotechnol 2011; 2011:473983. [PMID: 22190852 PMCID: PMC3228691 DOI: 10.1155/2011/473983] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2011] [Revised: 08/29/2011] [Accepted: 08/31/2011] [Indexed: 11/24/2022] Open
Abstract
Toxoplasma gondii proliferates and organizes within a parasitophorous vacuole in rosettes around a residual body and is surrounded by a membranous nanotubular network whose function remains unclear. Here, we characterized structure and function of the residual body in intracellular tachyzoites of the RH strain. Our data showed the residual body as a body limited by a membrane formed during proliferation of tachyzoites probably through the secretion of components and a pinching event of the membrane at the posterior end. It contributes in the intravacuolar parasite organization by the membrane connection between the tachyzoites posterior end and the residual body membrane to give place to the rosette conformation. Radial distribution of parasites in rosettes favors an efficient exteriorization. Absence of the network and presence of atypical residual bodies in a ΔGRA2-HXGPRT knock-out mutant affected the intravacuolar organization of tachyzoites and their exteriorization.
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34
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Portes JDA, Netto CD, da Silva AJM, Costa PRR, DaMatta RA, dos Santos TAT, De Souza W, Seabra SH. A new type of pterocarpanquinone that affects Toxoplasma gondii tachyzoites in vitro. Vet Parasitol 2011; 186:261-9. [PMID: 22177332 DOI: 10.1016/j.vetpar.2011.11.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2011] [Revised: 09/05/2011] [Accepted: 11/01/2011] [Indexed: 10/15/2022]
Abstract
Toxoplasma gondii, the agent of Toxoplasmosis, is an obligate intracellular protozoan able to infect a wide range of vertebrate cells, including nonprofessional and professional phagocytes. Therefore, drugs must have intracellular activities in order to control this parasite. The most common therapy for Toxoplasmosis is the combination of sulfadiazine and pyrimethamine. This treatment is associated with adverse reactions, thus, the development of new drugs is necessary. In previous studies, naphthoquinone derivatives showed anti-cancer activity functioning as agents capable of acting on groups of DNA, preventing cancer cells duplication. These derivatives also display anti-parasitic activity against Plasmodium falciparum and Leishmania amazonensis. The derivative pterocarpanquinone tested in this work resulted from the molecular hybridization between pterocarpans and naphtoquinone that presents anti-tumoral and anti-parasitic activities of lapachol. The aim of this work was to determine if this derivative is able to change T. gondii growth within LLC-MK2 cells. The drug did not arrest host cell growth, but was able to decrease the infection index of T. gondii with an IC(50) of 2.5 μM. Scanning and transmission electron microscopy analysis showed morphological changes of parasites including membrane damage. The parasite that survived tended to encyst as seen by Dolichos biflorus lectin staining and Bag-1 expression. These results suggest that pterocarpanquinones are drugs potentially important for the killing and encystment of T. gondii.
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Affiliation(s)
- Juliana de Araujo Portes
- Laboratório de Tecnologia em Cultura de Células, Centro Universitário Estadual da Zona Oeste (UEZO) - Av. Manuel Caldeira de Alvarenga, 1203, Campo Grande, Rio de Janeiro, RJ, CEP: 23070-200, Brazil.
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Lemgruber L, Lupetti P, Martins-Duarte ES, De Souza W, Vommaro RC. The organization of the wall filaments and characterization of the matrix structures of Toxoplasma gondii cyst form. Cell Microbiol 2011; 13:1920-32. [PMID: 21899696 DOI: 10.1111/j.1462-5822.2011.01681.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The encystation process is a key step in Toxoplasma gondii life cycle, allowing the parasite to escape from the host immune system and the transmission among the hosts. A detailed characterization of the formation and structure of the cyst stage is essential for a better knowledge of toxoplasmosis. Here we isolated cysts from mice brains and analysed the cyst wall structure and cyst matrix organization using different electron microscopy techniques. Images obtained showed that the cyst wall presented a filamentous aspect, with circular openings on its surface. The filaments were organized in two layers: a compact one, facing the exterior of the whole cyst and a more loosen one, facing the matrix. Within the cyst wall, we observed tubules and a large number of vesicles. The cyst matrix presented vesicles of different sizes and tubules, which were organized in a network connecting the bradyzoites to each other and to the cyst wall. Large vesicles, with a granular material in their lumen of glycidic nature were observed. Similar vesicles were also found associated with the posterior pole of the bradyzoites and in proximity to the cyst wall.
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Affiliation(s)
- Leandro Lemgruber
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
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Evidence for host cells as the major contributor of lipids in the intravacuolar network of Toxoplasma-infected cells. EUKARYOTIC CELL 2011; 10:1095-9. [PMID: 21685319 DOI: 10.1128/ec.00002-11] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The intracellular parasite Toxoplasma gondii develops inside a parasitophorous vacuole (PV) that derives from the host cell plasma membrane during invasion. Previous electron micrograph images have shown that the membrane of this vacuole undergoes an extraordinary remodeling with an extensive network of thin tubules and vesicles, the intravacuolar network (IVN), which fills the lumen of the PV. While dense granule proteins, secreted during and after invasion, are the main factors for the organization and tubulation of the network, little is known about the source of lipids used for this remodeling. By selectively labeling host cell or parasite membranes, we uncovered evidence that strongly supports the host cell as the primary, if not exclusive, source of lipids for parasite IVN remodeling. Fluorescence recovery after photobleaching (FRAP) microscopy experiments revealed that lipids are surprisingly dynamic within the parasitophorous vacuole and are continuously exchanged or replenished by the host cell. The results presented here suggest a new model for development of the parasitophorous vacuole whereby the host provides a continuous stream of lipids to support the growth and maturation of the PVM and IVN.
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Abstract
Toxoplasma gondii is an important human pathogen with a worldwide distribution. It is primarily of medical importance for pregnant women and immunocompromised patients. Primary infection of the former is often associated with fetal infection, which can lead to abortion or severe neonatal malformation. Immunocompromised patients are at risk of contracting the severe form of the disease that may be fatal. Thus, detection of T. gondii infection with high sensitivity and specificity is crucial in the management of the disease. Toxoplasmosis is generally diagnosed by demonstrating specific immunoglobulin M (IgM) and IgG antibodies to toxoplasma antigens in the patient's serum sample. Most of the commercially available tests use T. gondii native antigens and display wide variations in test accuracy. Recombinant antigens have great potential as diagnostic reagents for use in assays to detect toxoplasmosis. Thus in this review, we address recent advances in the use of Toxoplasma recombinant proteins for serodiagnosis of toxoplasmosis.
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Affiliation(s)
- Dupadahalli Kotresha
- Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia, Penang, Malaysia
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Abstract
Apicomplexan parasites like Toxoplasma gondii are distinctive in their utilization of para site encoded motor systems to invade cells. Invasion results in the establishment of the parasitophorous vacuole (PV) within the infected cell. Most apicomplexans complete their intracellular tenure within the infected cell in the PV that is demarcated from the host cytoplasm by the parasitophorous vacuole membrane (PVM). In this chapter I focus on the events surrounding the formation of the PVM and selected activities attributed to it. Its central role as the interface between the parasite and its immediate environment, the host cytoplasm, is validated by the diversity of functions attributed to it. While functions in structural organization, nutrient acquisitions and signaling have been defined their molecular bases remain largely unknown. Several recent studies and the decoding of the Toxoplasma genome have set the stage for a rapid expansion in our understanding of the role of the PVM in parasite biology. Toxoplasma gondii, like all apicomplexan parasites are obligate intracellular pathogens. This family of parasites utilize their own actin-myosin based motor systems to gain entry into susceptible cells establishing themselves, in some cases transiently (e.g., Theileria spp) in specialized vacuolar compartment, the parasitophorous vacuole (PV). The T. gondii PV is highly dynamic compartment defining the replication permissive niche for the parasite. The delimiting membrane defining the parasitophorous vacuole, the parasitophorous vacuole membrane or PVM is increasingly being recognized as a specialized "organelle" that in the context of the infected cell is extracorporeal to the parent organism, the parasite. A systematic study of this enigmatic organelle has been severely limited by several issues. Primary among these is the fact that it is formed only in the context of the infected cell thereby limiting the amount of material. Secondly, unlike other cellular organelles that can often be purified by conventional approaches, the PVM, cannot be purified away from host cell organelles (see below). In spite of these significant obstacles considerable progress has been made in recent years toward understanding the biogenesis of the PVM, identification of its protein complement and the characterization of activities within it. These studies demonstrate that the PVM, on its own and by virtue of its interactions with cellular components, plays critical functions in the structural integrity of the vacuole, nutrient acquisition and the manipulation of cellular functions. In addition it appears that the repertoire of activities at the PVM is likely to be plastic reflecting temporal changes associated with the replicative phase of parasite growth. Finally, the PVM likely forms the foundation for the cyst wall as the parasite differentiates in the establishment of latent infection. As the critical border crossing between the parasite and invaded cell the study of the PVM provides a fertile area for new investigation aided by the recent decoding of the Toxoplasma genome (available at wwww.ToxoDB.org) and the application of proteomic analyses to basic questions in parasite biology.
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Intervacuolar transport and unique topology of GRA14, a novel dense granule protein in Toxoplasma gondii. Infect Immun 2008; 76:4865-75. [PMID: 18765740 DOI: 10.1128/iai.00782-08] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Toxoplasma gondii is an obligate intracellular parasite that resides in the cytoplasm of its host in a unique membrane-bound vacuole known as the parasitophorous vacuole (PV). The membrane surrounding the parasite is remodeled by the dense granules, secretory organelles that release an array of proteins into the vacuole and to the PV membrane (PVM). Only a small portion of the protein constituents of the dense granules have been identified, and little is known regarding their roles in infection or how they are trafficked within the infected host cell. In this report, we identify a novel secreted dense granule protein, GRA14, and show that it is targeted to membranous structures within the vacuole known as the intravacuolar network and to the vacuolar membrane surrounding the parasite. We disrupted GRA14 and exploited the knockout strain to show that GRA14 can be transferred between vacuoles in a coinfection experiment with wild-type parasites. We also show that GRA14 has an unexpected topology in the PVM with its C terminus facing the host cytoplasm and its N terminus facing the vacuolar lumen. These findings have important implications both for the trafficking of GRA proteins to their ultimate destinations and for expectations of functional domains of GRA proteins at the host-parasite interface.
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40
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Abstract
Toxoplasma gondii is an obligate intracellular parasite that can infect virtually any nucleated cell. During invasion Toxoplasma creates the parasitophorous vacuole, a subcellular compartment that acts as an interface between the parasite and host, and serves as a platform for modulation of host cell functions that support parasite replication and infection. Spatial reorganization of host organelles and cytoskeleton around the parasitophorous vacuole are observed following entry, and recent evidence suggests this interior redecorating promotes parasite nutrient acquisition. New findings also reveal that Toxoplasma manipulates host signaling pathways by deploying parasite kinases and a phosphatase, including at least two that infiltrate the host nucleus. Toxoplasma infection additionally controls several cellular pathways to establish an anti-apoptotic environment, and subverts immune cells as a conduit for dissemination. In this review we discuss these recent developments in understanding how Toxoplasma achieves widespread success as a human and animal parasite by manipulating its host.
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Affiliation(s)
- J Laliberté
- Department of Microbiology and Immunology, University of Michigan Medical School, 1150 West Medical Center Drive, 5751 Medical Science Building II, Ann Arbor, Michigan 48109-0620, USA.
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Cesbron-Delauw MF, Gendrin C, Travier L, Ruffiot P, Mercier C. Apicomplexa in mammalian cells: trafficking to the parasitophorous vacuole. Traffic 2008; 9:657-64. [PMID: 18315533 DOI: 10.1111/j.1600-0854.2008.00728.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Most Apicomplexa reside and multiply in the cytoplasm of their host cell, within a parasitophorous vacuole (PV) originating from both parasite and host cell components. Trafficking of parasite-encoded proteins destined to membrane compartments beyond the confine of the parasite plasma membrane is a process that offers a rich territory to explore novel mechanisms of protein-membrane interactions. Here, we focus on the PVs formed by the asexual stages of two pathogens of medical importance, Plasmodium and Toxoplasma. We compare the PVs of both parasites, with a particular emphasis on their evolutionary divergent compartmentalization within the host cell. We also discuss the existence of peculiar export mechanisms and/or sorting determinants that are potentially involved in the post-secretory targeting of parasite proteins to the PV subcompartments.
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Affiliation(s)
- Marie-France Cesbron-Delauw
- Laboratoire Adaptation et Pathogénie des Microorganismes, CNRS UMR 5163, Université Joseph Fourier - Grenoble 1, BP 170, 38042 Grenoble Cedex 9, France.
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Lemgruber L, De Souza W, Vommaro RC. Freeze-fracture study of the dynamics of Toxoplasma gondii parasitophorous vacuole development. Micron 2008; 39:177-83. [PMID: 17317194 DOI: 10.1016/j.micron.2007.01.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2006] [Revised: 01/04/2007] [Accepted: 01/05/2007] [Indexed: 11/21/2022]
Abstract
Toxoplasma gondii resides in a nonfusogenic parasitophorous vacuole (PV), which provides a safe environment for parasite survival and replication. In this work, we used the freeze-fracture technique to analyze the PV during different times of T. gondii infection in an epithelial cell line. After a short time of interaction with host cell, T. gondii PV membrane already showed a significant quantity of intramembranous particles (IMPs)-293IMPs/microm(2). The IMP density evaluated did not vary until 6h of interaction. As the PV area enlarged with the progression of infection, the density of these particles increased, reaching a stable quantity in the order of 1100particles/microm(2). The IMPs were heterogeneous in size and were found distributed without any special pattern throughout the time of infection studied. The membrane lining the PV presented circular figures, which resembled vesicle fusion areas or attachments of the membranous tubular network, regions free from particles and small depressions, demonstrating to be a dynamic structure. IMPs were found in tubulo-vesicular structures present in the intravacuolar matrix, although rarely observed in elements of the intravacuolar network.
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Affiliation(s)
- Leandro Lemgruber
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
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Travier L, Mondragon R, Dubremetz JF, Musset K, Mondragon M, Gonzalez S, Cesbron-Delauw MF, Mercier C. Functional domains of the Toxoplasma GRA2 protein in the formation of the membranous nanotubular network of the parasitophorous vacuole. Int J Parasitol 2007; 38:757-73. [PMID: 18061598 DOI: 10.1016/j.ijpara.2007.10.010] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2007] [Revised: 10/14/2007] [Accepted: 10/19/2007] [Indexed: 02/07/2023]
Abstract
Amphipathic alpha-helices have been proposed as the general means used by soluble proteins to induce membrane tubulation. Previous studies had shown that the GRA2 dense granule protein of Toxoplasma gondii would be a crucial protein for the formation of the intravacuolar membranous nanotubular network (MNN) and that one of the functions of the MNN is to organise the parasites within the parasitophorous vacuole. GRA2 is a small protein (185 amino acids), predicted to contain three amphipathic alpha-helices (alpha1: 70-92; alpha2: 95-110 and alpha3: 119-139) when using the standard programs of secondary structure prediction. To investigate the respective contribution of each alpha-helix in the GRA2 functions, we used DeltaGRA2-HXGPRT knock-out complementation: eight truncated forms of GRA2 were expressed in the deleted recipient and the phenotypes of these mutants were analysed. This study showed that: (i) alpha3, when associated with the N-terminal region (NT) and the C-terminal region (CT), is sufficient to target the protein to the parasite posterior end and to induce formation of membranous vesicles within the vacuole. However, when associated only with CT, alpha3 is not sufficient to provide the hydrophobicity required for membrane association; (ii) the alpha1alpha2 region is alone not sufficient to induce membrane tubulation within the PV; and (iii) only one mutant, NT-alpha1alpha2alpha3, restores most of the biochemical and functional properties of GRA2, including traffic to the dense granules, secretion into the vacuole, association with vacuolar membranes, induction of the MNN formation and organisation of the parasites within the vacuole.
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Affiliation(s)
- Laetitia Travier
- Laboratoire Adaptation et Pathogénie des Micro-organismes, Université Joseph Fourier GRENOBLE 1, Centre National de la Recherche Scientifique UMR 5163, BP 170, Campus Santé, Domaine de la Merci, Grenoble cedex 9, France
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Braun L, Travier L, Kieffer S, Musset K, Garin J, Mercier C, Cesbron-Delauw MF. Purification of Toxoplasma dense granule proteins reveals that they are in complexes throughout the secretory pathway. Mol Biochem Parasitol 2007; 157:13-21. [PMID: 17959262 DOI: 10.1016/j.molbiopara.2007.09.002] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2007] [Revised: 09/07/2007] [Accepted: 09/12/2007] [Indexed: 11/18/2022]
Abstract
Dense granules are Apicomplexa specific secretory organelles. In Toxoplasma gondii, the dense granules proteins, named GRA proteins, are massively secreted into the parasitophorous vacuole (PV) shortly after invasion. Despite the presence of hydrophobic membrane segments, they are stored as both soluble and aggregated forms within the dense granules and are secreted as soluble forms into the vacuolar space where they further stably associate with PV membranes. In this study, we explored the unusual biochemical behavior of GRA proteins during their trafficking. Conventional chromatography indicated that the GRA proteins form high globular weight complexes within the parasite. To confirm these results, DeltaGRA knocked-out parasites were stably complemented with their respective HA-FLAG tagged GRA2 or GRA5. Purification of the tagged proteins by affinity chromatography showed that within the parasite and the PV soluble fraction, both the soluble GRA2-HA-FLAG and GRA5-HA-FLAG associate with several GRA proteins, the major ones being GRA3, GRA6 and GRA7. Following their insertion into the PV membranes, GRA2-HA-FLAG associated with GRA5 and GRA7 while GRA5-HA-FLAG associated with GRA7 only. Taken together, these data suggest that the GRA proteins form oligomeric complexes that may explain their solubility within the dense granules and the vacuolar matrix by sequestering their hydrophobic domains within the interior of the complex. Insertion into the PV membranes correlates with the decrease of the GRA partners number.
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Affiliation(s)
- Laurence Braun
- UMR 5163/CNRS-Université Joseph Fourier, Domaine de la Merci, 38700 Grenoble, France
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de Souza W, Campanati L, Attias M. Strategies and results of field emission scanning electron microscopy (FE-SEM) in the study of parasitic protozoa. Micron 2006; 39:77-87. [PMID: 17174097 DOI: 10.1016/j.micron.2006.11.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2006] [Accepted: 11/07/2006] [Indexed: 10/23/2022]
Abstract
Field emission scanning electron microscopy (FE-SEM) provides a range of strategies for investigating the structural organization of biological systems, varying from isolated macromolecules to tissue organization and whole organisms. This review covers some of the results so far obtained using FE-SEM observation and various protocols of sample fixation to analyze the structural organization of parasitic protozoa and their interaction with host cells. The employment of FE-SEM can be broadened through the use of gold-labeled molecules or tracers, gradual extraction by detergents, and cleavage techniques. These analyses provide significant contributions to the characterization of these organisms concerning ultrastructure, cytoskeleton, motility and intracellular behavior.
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Affiliation(s)
- Wanderley de Souza
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Ilha do Fundão, 21949-900 Rio de Janeiro, RJ, Brazil.
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Cunha MML, Franzen AJ, Alviano DS, Zanardi E, Alviano CS, De Souza W, Rozental S. Inhibition of melanin synthesis pathway by tricyclazole increases susceptibility ofFonsecaea pedrosoi against mouse macrophages. Microsc Res Tech 2005; 68:377-84. [PMID: 16358282 DOI: 10.1002/jemt.20260] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Fonsecaea pedrosoi produces melanin, a pigment related to virulence in pathogenic fungi. To understand the involvement of melanin in the protection of fungi, the authors used tricyclazole to inhibit the melanin pathway in F. pedrosoi. Experiments of pigmentation suggested that F. pedrosoi uniquely produces dihydroxynaphthalene-melanin. Pigments produced on cultures modified or not with tricyclazole were extracted by an alkali-acid method and submitted to infrared and ion exchange chromatography analysis; also cytochemistry analysis for cationized ferritin of whole cells was carried out. This group of experiments showed that the tricyclazole treatment on F. pedrosoi produced a melanin-like pigment, but less negatively charged and with less affinity for iron ions than that without the tricyclazole treatment, and this in turn lead to a less negatively charge cell wall surface. Scanning electron microscopy of such pigments showed that the melanin from control cultures maintained their hyphae-like structures, which have been described as "melanin-ghosts," whereas the tricyclazole pigment showed an amorphous surface. Interaction of conidia from cultures of F. pedrosoi, modified by tricyclazole or not, with peritoneal activated macrophages suggested that tricyclazole causes higher association of fungus with macrophages, weakens the fungus capacity to destroy the macrophages, and diminishes the resistance to dry fracture procedures on samples prepared for high resolution scanning electron microscopy.
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Affiliation(s)
- Marcel M L Cunha
- Laboratório de Biologia Celular de Fungos, Instituto de Biofísica Carlos Chagas Filho (IBCCF), Centro de Ciências da Saúde (CCS), Universidade Federal do Rio de Janeiro (UFRJ), Bloco G, Ilha do Fundão, Rio de Janeiro 21949-900, Brazil
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