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Greigert V, Bittich-Fahmi F, Pfaff AW. Pathophysiology of ocular toxoplasmosis: Facts and open questions. PLoS Negl Trop Dis 2020; 14:e0008905. [PMID: 33382688 PMCID: PMC7774838 DOI: 10.1371/journal.pntd.0008905] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Infections with the protozoan parasite Toxoplasma gondii are frequent, but one of its main consequences, ocular toxoplasmosis (OT), remains poorly understood. While its clinical description has recently attracted more attention and publications, the underlying pathophysiological mechanisms are only sparsely elucidated, which is partly due to the inherent difficulties to establish relevant animal models. Furthermore, the particularities of the ocular environment explain why the abundant knowledge on systemic toxoplasmosis cannot be just transferred to the ocular situation. However, studies undertaken in mouse models have revealed a central role of interferon gamma (IFNγ) and, more surprisingly, interleukin 17 (IL17), in ocular pathology and parasite control. These studies also show the importance of the genetic background of the infective Toxoplasma strain. Indeed, infections due to exotic strains show a completely different pathophysiology, which translates in a different clinical outcome. These elements should lead to more individualized therapy. Furthermore, the recent advance in understanding the immune response during OT paved the way to new research leads, involving immune pathways poorly studied in this particular setting, such as type I and type III interferons. In any case, deeper knowledge of the mechanisms of this pathology is needed to establish new, more targeted treatment schemes.
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Affiliation(s)
- Valentin Greigert
- Institut de Parasitologie et Pathologie Tropicale, UR 7292, Fédération de Médecine Translationnelle, Université de Strasbourg, Strasbourg, France
| | - Faiza Bittich-Fahmi
- Institut de Parasitologie et Pathologie Tropicale, UR 7292, Fédération de Médecine Translationnelle, Université de Strasbourg, Strasbourg, France
| | - Alexander W. Pfaff
- Institut de Parasitologie et Pathologie Tropicale, UR 7292, Fédération de Médecine Translationnelle, Université de Strasbourg, Strasbourg, France
- Service de Parasitologie et Mycologie Médicale, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
- * E-mail:
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2
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Poncet AF, Blanchard N, Marion S. Toxoplasma and Dendritic Cells: An Intimate Relationship That Deserves Further Scrutiny. Trends Parasitol 2019; 35:870-886. [PMID: 31492624 DOI: 10.1016/j.pt.2019.08.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 08/01/2019] [Accepted: 08/04/2019] [Indexed: 02/07/2023]
Abstract
Toxoplasma gondii (Tg), an obligate intracellular parasite of the phylum Apicomplexa, infects a wide range of animals, including humans. A hallmark of Tg infection is the subversion of host responses, which is thought to favor parasite persistence and propagation to new hosts. Recently, a variety of parasite-secreted modulatory effectors have been uncovered in fibroblasts and macrophages, but the specific interplay between Tg and dendritic cells (DCs) is just beginning to emerge. In this review, we summarize the current knowledge on Tg-DC interactions, including innate recognition, cytokine production, and antigen presentation, and discuss open questions regarding how Tg-secreted effectors may shape DC functions to perturb innate and adaptive immunity.
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Affiliation(s)
- Anaïs F Poncet
- Centre d'Infection et d'Immunité de Lille, Université de Lille, Inserm U1019, CNRS UMR 8204, CHU Lille, Institut Pasteur de Lille, Lille, France
| | - Nicolas Blanchard
- Centre de Physiopathologie Toulouse Purpan (CPTP), Université de Toulouse, INSERM, CNRS, UPS, Toulouse, France. @inserm.fr
| | - Sabrina Marion
- Centre d'Infection et d'Immunité de Lille, Université de Lille, Inserm U1019, CNRS UMR 8204, CHU Lille, Institut Pasteur de Lille, Lille, France. @pasteur-lille.fr
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3
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Bhandage AK, Barragan A. Calling in the Ca Valry- Toxoplasma gondii Hijacks GABAergic Signaling and Voltage-Dependent Calcium Channel Signaling for Trojan horse-Mediated Dissemination. Front Cell Infect Microbiol 2019; 9:61. [PMID: 30949456 PMCID: PMC6436472 DOI: 10.3389/fcimb.2019.00061] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2018] [Accepted: 02/27/2019] [Indexed: 12/11/2022] Open
Abstract
Dendritic cells (DCs) are regarded as the gatekeepers of the immune system but can also mediate systemic dissemination of the obligate intracellular parasite Toxoplasma gondii. Here, we review the current knowledge on how T. gondii hijacks the migratory machinery of DCs and microglia. Shortly after active invasion by the parasite, infected cells synthesize and secrete the neurotransmitter γ-aminobutyric acid (GABA) and activate GABA-A receptors, which sets on a hypermigratory phenotype in parasitized DCs in vitro and in vivo. The signaling molecule calcium plays a central role for this migratory activation as signal transduction following GABAergic activation is mediated via the L-type voltage-dependent calcium channel (L-VDCC) subtype Cav1.3. These studies have revealed that DCs possess a GABA/L-VDCC/Cav1.3 motogenic signaling axis that triggers migratory activation upon T. gondii infection. Moreover, GABAergic migration can cooperate with chemotactic responses. Additionally, the parasite-derived protein Tg14-3-3 has been associated with hypermigration of DCs and microglia. We discuss the interference of T. gondii infection with host cell signaling pathways that regulate migration. Altogether, T. gondii hijacks non-canonical signaling pathways in infected immune cells to modulate their migratory properties, and thereby promote its own dissemination.
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Affiliation(s)
| | - Antonio Barragan
- Department of Molecular Biosciences, The Wenner-Gren Institute (MBW), Stockholm University, Stockholm, Sweden
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4
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Cook JH, Ueno N, Lodoen MB. Toxoplasma gondii disrupts β1 integrin signaling and focal adhesion formation during monocyte hypermotility. J Biol Chem 2018; 293:3374-3385. [PMID: 29295815 PMCID: PMC5836128 DOI: 10.1074/jbc.m117.793281] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Revised: 12/14/2017] [Indexed: 01/13/2023] Open
Abstract
The motility of blood monocytes is orchestrated by the activity of cell-surface integrins, which translate extracellular signals into cytoskeletal changes to mediate adhesion and migration. Toxoplasma gondii is an intracellular parasite that infects migratory cells and enhances their motility, but the mechanisms underlying T. gondii-induced hypermotility are incompletely understood. We investigated the molecular basis for the hypermotility of primary human peripheral blood monocytes and THP-1 cells infected with T. gondii Compared with uninfected monocytes, T. gondii infection of monocytes reduced cell spreading and the number of activated β1 integrin clusters in contact with fibronectin during settling, an effect not observed in monocytes treated with lipopolysaccharide (LPS) or Escherichia coli Furthermore, T. gondii infection disrupted the phosphorylation of focal adhesion kinase (FAK) at tyrosine 397 (Tyr-397) and Tyr-925 and of the related protein proline-rich tyrosine kinase (Pyk2) at Tyr-402. The localization of paxillin, FAK, and vinculin to focal adhesions and the colocalization of these proteins with activated β1 integrins were also impaired in T. gondii-infected monocytes. Using time-lapse confocal microscopy of THP-1 cells expressing enhanced GFP (eGFP)-FAK during settling on fibronectin, we found that T. gondii-induced monocyte hypermotility was characterized by a reduced number of enhanced GFP-FAK-containing clusters over time compared with uninfected cells. This study demonstrates an integrin conformation-independent regulation of the β1 integrin adhesion pathway, providing further insight into the molecular mechanism of T. gondii-induced monocyte hypermotility.
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Affiliation(s)
- Joshua H Cook
- From the Department of Molecular Biology and Biochemistry and the Institute for Immunology, University of California, Irvine, California, 92697
| | - Norikiyo Ueno
- From the Department of Molecular Biology and Biochemistry and the Institute for Immunology, University of California, Irvine, California, 92697
| | - Melissa B Lodoen
- From the Department of Molecular Biology and Biochemistry and the Institute for Immunology, University of California, Irvine, California, 92697
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5
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Insights into the molecular basis of host behaviour manipulation by Toxoplasma gondii infection. Emerg Top Life Sci 2017; 1:563-572. [PMID: 33525856 DOI: 10.1042/etls20170108] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Revised: 11/22/2017] [Accepted: 11/27/2017] [Indexed: 12/22/2022]
Abstract
Typically illustrating the 'manipulation hypothesis', Toxoplasma gondii is widely known to trigger sustainable behavioural changes during chronic infection of intermediate hosts to enhance transmission to its feline definitive hosts, ensuring survival and dissemination. During the chronic stage of infection in rodents, a variety of neurological dysfunctions have been unravelled and correlated with the loss of cat fear, among other phenotypic impacts. However, the underlying neurological alteration(s) driving these behavioural modifications is only partially understood, which makes it difficult to draw more than a correlation between T. gondii infection and changes in brain homeostasis. Moreover, it is barely known which among the brain regions governing fear and stress responses are preferentially affected during T. gondii infection. Studies aiming at an in-depth dissection of underlying molecular mechanisms occurring at the host and parasite levels will be discussed in this review. Addressing this reminiscent topic in the light of recent technical progress and new discoveries regarding fear response, olfaction and neuromodulator mechanisms could contribute to a better understanding of this complex host-parasite interaction.
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Buaillon C, Guerrero NA, Cebrian I, Blanié S, Lopez J, Bassot E, Vasseur V, Santi-Rocca J, Blanchard N. MHC I presentation of Toxoplasma gondii immunodominant antigen does not require Sec22b and is regulated by antigen orientation at the vacuole membrane. Eur J Immunol 2017; 47:1160-1170. [PMID: 28508576 DOI: 10.1002/eji.201646859] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 03/21/2017] [Accepted: 05/09/2017] [Indexed: 12/16/2022]
Abstract
The intracellular Toxoplasma gondii parasite replicates within a parasitophorous vacuole (PV). T. gondii secretes proteins that remain soluble in the PV space, are inserted into PV membranes or are exported beyond the PV boundary. In addition to supporting T. gondii growth, these proteins can be processed and presented by MHC I for CD8+ T-cell recognition. Yet it is unclear whether membrane binding influences the processing pathways employed and if topology of membrane antigens impacts their MHC I presentation. Here we report that the MHC I pathways of soluble and membrane-bound antigens differ in their requirement for host ER recruitment. In contrast to the soluble SAG1-OVA model antigen, we find that presentation of the membrane-bound GRA6 is independent from the SNARE Sec22b, a key molecule for transfer of host endoplasmic reticulum components onto the PV. Using parasites modified to secrete a transmembrane antigen with opposite orientations, we further show that MHC I presentation is highly favored when the C-terminal epitope is exposed to the host cell cytosol, which corresponds to GRA6 natural orientation. Our data suggest that the biochemical properties of antigens released by intracellular pathogens critically guide their processing pathway and are valuable parameters to consider for vaccination strategies.
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Affiliation(s)
- Célia Buaillon
- Centre de Physiopathologie Toulouse Purpan (CPTP), INSERM, CNRS, Université de Toulouse, UPS, Toulouse, France
| | - Nestor A Guerrero
- Centre de Physiopathologie Toulouse Purpan (CPTP), INSERM, CNRS, Université de Toulouse, UPS, Toulouse, France
| | - Ignacio Cebrian
- Instituto de Histología y Embriología de Mendoza (IHEM)-CONICET/UNCuyo, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Mendoza, Argentina
| | - Sophie Blanié
- Centre de Physiopathologie Toulouse Purpan (CPTP), INSERM, CNRS, Université de Toulouse, UPS, Toulouse, France
| | - Jodie Lopez
- Centre de Physiopathologie Toulouse Purpan (CPTP), INSERM, CNRS, Université de Toulouse, UPS, Toulouse, France
| | - Emilie Bassot
- Centre de Physiopathologie Toulouse Purpan (CPTP), INSERM, CNRS, Université de Toulouse, UPS, Toulouse, France
| | - Virginie Vasseur
- Centre de Physiopathologie Toulouse Purpan (CPTP), INSERM, CNRS, Université de Toulouse, UPS, Toulouse, France
| | - Julien Santi-Rocca
- Centre de Physiopathologie Toulouse Purpan (CPTP), INSERM, CNRS, Université de Toulouse, UPS, Toulouse, France
| | - Nicolas Blanchard
- Centre de Physiopathologie Toulouse Purpan (CPTP), INSERM, CNRS, Université de Toulouse, UPS, Toulouse, France
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7
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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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8
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Hammoudi PM, Jacot D, Mueller C, Di Cristina M, Dogga SK, Marq JB, Romano J, Tosetti N, Dubrot J, Emre Y, Lunghi M, Coppens I, Yamamoto M, Sojka D, Pino P, Soldati-Favre D. Fundamental Roles of the Golgi-Associated Toxoplasma Aspartyl Protease, ASP5, at the Host-Parasite Interface. PLoS Pathog 2015; 11:e1005211. [PMID: 26473595 PMCID: PMC4608785 DOI: 10.1371/journal.ppat.1005211] [Citation(s) in RCA: 86] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2015] [Accepted: 09/16/2015] [Indexed: 11/18/2022] Open
Abstract
Toxoplasma gondii possesses sets of dense granule proteins (GRAs) that either assemble at, or cross the parasitophorous vacuole membrane (PVM) and exhibit motifs resembling the HT/PEXEL previously identified in a repertoire of exported Plasmodium proteins. Within Plasmodium spp., cleavage of the HT/PEXEL motif by the endoplasmic reticulum-resident protease Plasmepsin V precedes trafficking to and export across the PVM of proteins involved in pathogenicity and host cell remodelling. Here, we have functionally characterized the T. gondii aspartyl protease 5 (ASP5), a Golgi-resident protease that is phylogenetically related to Plasmepsin V. We show that deletion of ASP5 causes a significant loss in parasite fitness in vitro and an altered virulence in vivo. Furthermore, we reveal that ASP5 is necessary for the cleavage of GRA16, GRA19 and GRA20 at the PEXEL-like motif. In the absence of ASP5, the intravacuolar nanotubular network disappears and several GRAs fail to localize to the PVM, while GRA16 and GRA24, both known to be targeted to the host cell nucleus, are retained within the vacuolar space. Additionally, hypermigration of dendritic cells and bradyzoite cyst wall formation are impaired, critically impacting on parasite dissemination and persistence. Overall, the absence of ASP5 dramatically compromises the parasite’s ability to modulate host signalling pathways and immune responses. The opportunistic pathogen Toxoplasma gondii infects a large range of nucleated cells where it replicates intracellularly within a parasitophorous vacuole (PV) surrounded by a membrane (PVM). Parasites constitutively secrete dense-granule proteins (GRAs) both into and beyond the PV which participate in remodelling of the PVM, recruitment of host organelles, neutralization of the host cellular defences, and subversion of host cell functioning. In addition, the GRAs critically contribute to cyst wall formation, a process that critically ensures parasite persistence and transmission. To act as effector molecules, some of the GRAs must be translocated across the PVM. Within the related apicomplexan parasite P. falciparum, a repertoire of proteins exported beyond the PVM contain a motif cleaved by a specific protease, Plasmepsin V. Examination of the repertoire of GRAs in T. gondii revealed that some proteins exhibit such export-like motifs suggestive of protease involvement. In this study, we have functionally characterized the related aspartyl protease 5 (TgASP5) in both virulent and persistent T. gondii strains, and have investigated the phenotypic consequences of its deletion in the context of overall parasite biology, its intracellular niche, the infected host cells and the murine model. Our findings revealed fundamental roles of TgASP5 at the host-parasite interface.
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Affiliation(s)
- Pierre-Mehdi Hammoudi
- Department of Microbiology and Molecular Medicine, Centre Médical Universitaire, University of Geneva, Geneva, Switzerland
| | - Damien Jacot
- Department of Microbiology and Molecular Medicine, Centre Médical Universitaire, University of Geneva, Geneva, Switzerland
| | - Christina Mueller
- Department of Microbiology and Molecular Medicine, Centre Médical Universitaire, University of Geneva, Geneva, Switzerland
- Department of Immunoparasitology, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
| | - Manlio Di Cristina
- Department of Chemistry, Biology and Biotechnology, University of Perugia, Perugia, Italy
| | - Sunil Kumar Dogga
- Department of Microbiology and Molecular Medicine, Centre Médical Universitaire, University of Geneva, Geneva, Switzerland
| | - Jean-Baptiste Marq
- Department of Microbiology and Molecular Medicine, Centre Médical Universitaire, University of Geneva, Geneva, Switzerland
| | - Julia Romano
- Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - Nicolò Tosetti
- Department of Microbiology and Molecular Medicine, Centre Médical Universitaire, University of Geneva, Geneva, Switzerland
| | - Juan Dubrot
- Department of Pathology and Immunology, Centre Médical Universitaire, University of Geneva, Geneva, Switzerland
| | - Yalin Emre
- Department of Pathology and Immunology, Centre Médical Universitaire, University of Geneva, Geneva, Switzerland
| | - Matteo Lunghi
- Department of Chemistry, Biology and Biotechnology, University of Perugia, Perugia, Italy
| | - Isabelle Coppens
- Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - Masahiro Yamamoto
- Department of Immunoparasitology, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
| | - Daniel Sojka
- Department of Microbiology and Molecular Medicine, Centre Médical Universitaire, University of Geneva, Geneva, Switzerland
- Institute of Parasitology, Biology Centre of the Academy of Sciences of the Czech Republic, České Budějovice, Czech Republic
| | - Paco Pino
- Department of Microbiology and Molecular Medicine, Centre Médical Universitaire, University of Geneva, Geneva, Switzerland
| | - Dominique Soldati-Favre
- Department of Microbiology and Molecular Medicine, Centre Médical Universitaire, University of Geneva, Geneva, Switzerland
- * E-mail:
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9
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Leroux LP, Dasanayake D, Rommereim LM, Fox BA, Bzik DJ, Jardim A, Dzierszinski FS. Secreted Toxoplasma gondii molecules interfere with expression of MHC-II in interferon gamma-activated macrophages. Int J Parasitol 2015; 45:319-32. [PMID: 25720921 DOI: 10.1016/j.ijpara.2015.01.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Revised: 01/16/2015] [Accepted: 01/18/2015] [Indexed: 11/15/2022]
Abstract
The obligate intracellular protozoan parasite Toxoplasma gondii interferes with major histocompatibility complex class II antigen presentation to dampen host CD4(+) T cell responses. While it is known that T. gondii inhibits major histocompatibility complex class II gene transcription and expression in infected host cells, the mechanism of this host manipulation is unknown. Here, we show that soluble parasite proteins inhibit IFNγ-induced expression of major histocompatibility complex class II on the surface of the infected cell in a dose-dependent response that was abolished by protease treatment. Subcellular fractionation of T. gondii tachyzoites revealed that the major histocompatibility complex class II inhibitory activity co-partitioned with rhoptries and/or dense granules. However, parasite mutants deleted for single rhoptries or dense granules genes (ROP1, 4/7, 14, 16 and 18 or GRA 2-9 and 12 knock-out strains) retained the ability to inhibit expression of major histocompatibility complex class II. In addition, excreted/secreted antigens released by extracellular tachyzoites displayed immunomodulatory activity characterized by an inhibition of major histocompatibility complex class II expression, and reduced expression and release of TNFα by macrophages. Tandem MS analysis of parasite excreted/secreted antigens generated a list of T. gondii secreted proteins that may participate in major histocompatibility complex class II inhibition and the modulation of host immune functions.
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Affiliation(s)
- Louis-Philippe Leroux
- Institute of Parasitology, McGill University, Parasitology Building, 21,111 Lakeshore Road, Sainte-Anne-de-Bellevue, QC H9X 3V9, Canada; Centre for Host-Parasite Interaction, McGill University, Parasitology Building, 21,111 Lakeshore Road, Sainte-Anne-de-Bellevue, QC H9X 3V9, Canada
| | - Dayal Dasanayake
- Institute of Parasitology, McGill University, Parasitology Building, 21,111 Lakeshore Road, Sainte-Anne-de-Bellevue, QC H9X 3V9, Canada; Centre for Host-Parasite Interaction, McGill University, Parasitology Building, 21,111 Lakeshore Road, Sainte-Anne-de-Bellevue, QC H9X 3V9, Canada
| | - Leah M Rommereim
- Geisel School of Medicine at Dartmouth, Borwell Research Building, 1 Medical Center Drive, Lebanon, NH 03756, USA
| | - Barbara A Fox
- Geisel School of Medicine at Dartmouth, Borwell Research Building, 1 Medical Center Drive, Lebanon, NH 03756, USA
| | - David J Bzik
- Geisel School of Medicine at Dartmouth, Borwell Research Building, 1 Medical Center Drive, Lebanon, NH 03756, USA
| | - Armando Jardim
- Institute of Parasitology, McGill University, Parasitology Building, 21,111 Lakeshore Road, Sainte-Anne-de-Bellevue, QC H9X 3V9, Canada; Centre for Host-Parasite Interaction, McGill University, Parasitology Building, 21,111 Lakeshore Road, Sainte-Anne-de-Bellevue, QC H9X 3V9, Canada.
| | - Florence S Dzierszinski
- Institute of Parasitology, McGill University, Parasitology Building, 21,111 Lakeshore Road, Sainte-Anne-de-Bellevue, QC H9X 3V9, Canada; Carleton University Research Office, Dunton Tower, 1125 Colonel By Drive, Ottawa, ON K1S 5B6, Canada
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10
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Harker KS, Ueno N, Lodoen MB. Toxoplasma gondiidissemination: a parasite's journey through the infected host. Parasite Immunol 2015; 37:141-9. [DOI: 10.1111/pim.12163] [Citation(s) in RCA: 107] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2014] [Accepted: 11/11/2014] [Indexed: 12/30/2022]
Affiliation(s)
- K. S. Harker
- Department of Molecular Biology and Biochemistry and the Institute for Immunology; University of California; Irvine CA USA
| | - N. Ueno
- Department of Molecular Biology and Biochemistry and the Institute for Immunology; University of California; Irvine CA USA
| | - M. B. Lodoen
- Department of Molecular Biology and Biochemistry and the Institute for Immunology; University of California; Irvine CA USA
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11
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Mercier C, Cesbron-Delauw MF. Toxoplasma secretory granules: one population or more? Trends Parasitol 2015; 31:60-71. [PMID: 25599584 DOI: 10.1016/j.pt.2014.12.002] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Revised: 12/10/2014] [Accepted: 12/10/2014] [Indexed: 01/20/2023]
Abstract
In Toxoplasma gondii, dense granules are known as the storage secretory organelles of the so-called GRA proteins (for dense granule proteins), which are destined to the parasitophorous vacuole (PV) and the PV-derived cyst wall. Recently, newly annotated GRA proteins targeted to the host cell nucleus have enlarged this view. Here we provide an update on the latest developments on the Toxoplasma secreted proteins, which to date have been mainly studied at both the tachyzoite and bradyzoite stages, and we point out that recent discoveries could open the issue of a possible, yet uncharacterized, distinct secretory pathway in Toxoplasma.
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Affiliation(s)
- Corinne Mercier
- Laboratoire Adaptation et Pathogénie des Microorganismes (LAPM), CNRS UMR 5163 - Université Joseph Fourier, Grenoble, France.
| | - Marie-France Cesbron-Delauw
- Laboratoire Adaptation et Pathogénie des Microorganismes (LAPM), CNRS UMR 5163 - Université Joseph Fourier, Grenoble, France.
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12
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Lee IP, Evans AK, Yang C, Works MG, Kumar V, De Miguel Z, Manley NC, Sapolsky RM. Toxoplasma gondii is dependent on glutamine and alters migratory profile of infected host bone marrow derived immune cells through SNAT2 and CXCR4 pathways. PLoS One 2014; 9:e109803. [PMID: 25299045 PMCID: PMC4192591 DOI: 10.1371/journal.pone.0109803] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Accepted: 09/12/2014] [Indexed: 01/16/2023] Open
Abstract
The obligate intracellular parasite, Toxoplasma gondii, disseminates through its host inside infected immune cells. We hypothesize that parasite nutrient requirements lead to manipulation of migratory properties of the immune cell. We demonstrate that 1) T. gondii relies on glutamine for optimal infection, replication and viability, and 2) T. gondii-infected bone marrow-derived dendritic cells (DCs) display both “hypermotility” and “enhanced migration” to an elevated glutamine gradient in vitro. We show that glutamine uptake by the sodium-dependent neutral amino acid transporter 2 (SNAT2) is required for this enhanced migration. SNAT2 transport of glutamine is also a significant factor in the induction of migration by the small cytokine stromal cell-derived factor-1 (SDF-1) in uninfected DCs. Blocking both SNAT2 and C-X-C chemokine receptor 4 (CXCR4; the unique receptor for SDF-1) blocks hypermotility and the enhanced migration in T. gondii-infected DCs. Changes in host cell protein expression following T. gondii infection may explain the altered migratory phenotype; we observed an increase of CD80 and unchanged protein level of CXCR4 in both T. gondii-infected and lipopolysaccharide (LPS)-stimulated DCs. However, unlike activated DCs, SNAT2 expression in the cytosol of infected cells was also unchanged. Thus, our results suggest an important role of glutamine transport via SNAT2 in immune cell migration and a possible interaction between SNAT2 and CXCR4, by which T. gondii manipulates host cell motility.
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Affiliation(s)
- I-Ping Lee
- Department of Biology, Stanford University, Stanford, California, United States of America
- * E-mail:
| | - Andrew K. Evans
- Department of Biology, Stanford University, Stanford, California, United States of America
| | - Cissy Yang
- Department of Biology, Stanford University, Stanford, California, United States of America
| | - Melissa G. Works
- Department of Biology, Stanford University, Stanford, California, United States of America
| | - Vineet Kumar
- School of Biological Sciences, Nanyang Technological University, Singapore, Republic of Singapore
| | - Zurine De Miguel
- Department of Biology, Stanford University, Stanford, California, United States of America
| | - Nathan C. Manley
- Department of Biology, Stanford University, Stanford, California, United States of America
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, California, United States of America
- Stanford Stroke Center and Stanford Institute for Neuro-Innovation and Translational Neurosciences, Stanford University School of Medicine, Stanford, California, United States of America
| | - Robert M. Sapolsky
- Department of Biology, Stanford University, Stanford, California, United States of America
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, California, United States of America
- Stanford Stroke Center and Stanford Institute for Neuro-Innovation and Translational Neurosciences, Stanford University School of Medicine, Stanford, California, United States of America
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, California, United States of America
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13
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Ueno N, Harker KS, Clarke EV, McWhorter FY, Liu WF, Tenner AJ, Lodoen MB. Real-time imaging of Toxoplasma-infected human monocytes under fluidic shear stress reveals rapid translocation of intracellular parasites across endothelial barriers. Cell Microbiol 2013; 16:580-95. [PMID: 24245749 DOI: 10.1111/cmi.12239] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2013] [Revised: 10/15/2013] [Accepted: 11/11/2013] [Indexed: 12/24/2022]
Abstract
Peripheral blood monocytes are actively infected by Toxoplasma gondii and can function as 'Trojan horses' for parasite spread in the bloodstream. Using dynamic live-cell imaging, we visualized the transendothelial migration (TEM) of T. gondii-infected primary human monocytes during the initial minutes following contact with human endothelium. On average, infected and uninfected monocytes required only 9.8 and 4.1 min, respectively, to complete TEM. Infection increased monocyte crawling distances and velocities on endothelium, but overall TEM frequencies were comparable between infected and uninfected cells. In the vasculature, monocytes adhere to endothelium under the conditions of shear stress found in rapidly flowing blood. Remarkably, the addition of fluidic shear stress increased the TEM frequency of infected monocytes 4.5-fold compared to static conditions (to 45.2% from 10.3%). Infection led to a modest increase in expression of the high-affinityconformation of the monocyte integrin Mac-1 (CD11b/CD18), and Mac-1 accumulated near endothelial junctions during TEM. Blocking Mac-1 inhibited the crawling and TEM of infected monocytes to a greater degree than uninfected monocytes, and blocking the Mac-1 ligand, ICAM-1, dramatically reduced crawling and TEM for both populations. These findings contribute to a greater understanding of parasite dissemination from the vasculature into tissues.
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Affiliation(s)
- Norikiyo Ueno
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA, USA; Institute for Immunology, University of California, Irvine, CA, USA
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14
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Weidner JM, Barragan A. Tightly regulated migratory subversion of immune cells promotes the dissemination of Toxoplasma gondii. Int J Parasitol 2013; 44:85-90. [PMID: 24184911 DOI: 10.1016/j.ijpara.2013.09.006] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Revised: 08/26/2013] [Accepted: 09/17/2013] [Indexed: 01/13/2023]
Abstract
While the spread of Toxoplasma gondii within the infected human or animal host is associated with pathology, the pathways of dissemination have remained enigmatic. From the time point of entry into the gut, to the quiescent chronic infection in the central nervous system, Toxoplasma is detected and surveyed by immune cells that populate the tissues, for example dendritic cells. Paradoxically, this protective migratory function of leukocytes appears to be targeted by Toxoplasma to mediate its dissemination in the organism. Recent findings show that tightly regulated events take place shortly after host cell invasion that promote the migratory activation of infected dendritic cells. Here, we review the emerging knowledge on how this obligate intracellular protozoan orchestrates the subversion of leukocytes to achieve systemic dissemination and reach peripheral organs where pathology manifests.
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Affiliation(s)
- Jessica M Weidner
- Center for Infectious Medicine, Department of Medicine, Karolinska Institutet, Stockholm, Sweden; Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Antonio Barragan
- Center for Infectious Medicine, Department of Medicine, Karolinska Institutet, Stockholm, Sweden; Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden.
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15
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Harker KS, Ueno N, Wang T, Bonhomme C, Liu W, Lodoen MB. Toxoplasma gondii modulates the dynamics of human monocyte adhesion to vascular endothelium under fluidic shear stress. J Leukoc Biol 2013; 93:789-800. [PMID: 23485448 DOI: 10.1189/jlb.1012517] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Toxoplasma gondii actively infects circulating immune cells, including monocytes and DCs, and is thought to use these cells as Trojan horses for parasite dissemination. To investigate the interactions of T. gondii-infected human monocytes with vascular endothelium under conditions of shear stress, we developed a fluidic and time-lapse fluorescence microscopy system. Both uninfected and infected monocytes rolled, decelerated, and firmly adhered on TNF-α-activated endothelium. Interestingly, T. gondii-infected primary human monocytes and THP-1 cells exhibited altered adhesion dynamics compared with uninfected monocytes: infected cells rolled at significantly higher velocities (2.5- to 4.6-fold) and over greater distances (2.6- to 4.8-fold) than uninfected monocytes, before firmly adhering. During monocyte searching, 29-36% of infected monocytes compared with 0-11% of uninfected monocytes migrated >10 μm from the point where they initiated searching, and these "wandering" searches were predominantly in the direction of flow. As infected monocytes appeared delayed in their transition to firm adhesion, we examined the effects of infection on integrin expression and function. T. gondii did not affect the expression of LFA-1, VLA-4, or MAC-1 or the ability of Mn(2+) to activate these integrins. However, T. gondii infection impaired LFA-1 and VLA-4 clustering and pseudopod extension in response to integrin ligands. Surprisingly, a single intracellular parasite was sufficient to mediate these effects. This research has established a system for studying pathogen modulation of human leukocyte adhesion under conditions of physiological shear stress and has revealed a previously unappreciated effect of T. gondii infection on ligand-dependent integrin clustering.
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Affiliation(s)
- Katherine S Harker
- Department of Molecular Biology and Biochemistry and Institute for Immunology, University of California, Irvine, California 92697, USA
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