1
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Hryckowian ND, Ramírez-Flores CJ, Zinda C, Park SC, Kelty MT, Knoll LJ. Host cell-specific metabolism of linoleic acid controls Toxoplasma gondii growth in cell culture. Infect Immun 2024:e0029924. [PMID: 39194219 DOI: 10.1128/iai.00299-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2024] [Accepted: 07/19/2024] [Indexed: 08/29/2024] Open
Abstract
The obligate intracellular parasite Toxoplasma gondii can infect and replicate in any warm-blooded cell tested to date, but much of our knowledge about T. gondii cell biology comes from just one host cell type: human foreskin fibroblasts (HFFs). To expand our knowledge of host-parasite lipid interactions, we studied T. gondii in intestinal epithelial cells, the first site of host-parasite contact following oral infection and the exclusive site of parasite sexual development in feline hosts. We found that highly metabolic Caco-2 cells are permissive to T. gondii growth even when treated with high levels of linoleic acid (LA), a polyunsaturated fatty acid (PUFA) that kills parasites in HFFs. Caco-2 cells appear to sequester LA away from the parasite, preventing membrane disruptions and lipotoxicity that characterize LA-induced parasite death in HFFs. Our work is an important step toward understanding host-parasite interactions in feline intestinal epithelial cells, an understudied but important cell type in the T. gondii life cycle.
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Affiliation(s)
- Nicole D Hryckowian
- Department of Medical Microbiology & Immunology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Carlos J Ramírez-Flores
- Department of Medical Microbiology & Immunology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Caitlin Zinda
- Department of Medical Microbiology & Immunology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Sung Chul Park
- Department of Medical Microbiology & Immunology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Martin T Kelty
- Department of Medical Microbiology & Immunology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Laura J Knoll
- Department of Medical Microbiology & Immunology, University of Wisconsin-Madison, Madison, Wisconsin, USA
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2
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Aguiar A, Menezes de Brito ASS, Santos AGAD, Watanabe PDS, Cuman RKN, Trevizan AR, de Lima LL, Bersani-Amado CA, Rinaldi JDC, Sant Ana DDMG, Nogueira-Melo GDA. Mastocytosis and intraepithelial lymphocytosis in the ileum and colon characterize chronic Toxoplasma gondii infection in mice. Tissue Cell 2024; 91:102533. [PMID: 39213782 DOI: 10.1016/j.tice.2024.102533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Revised: 08/13/2024] [Accepted: 08/22/2024] [Indexed: 09/04/2024]
Abstract
Toxoplasma gondii is the causative agent of toxoplasmosis, a common zoonotic disease affecting vertebrates with high global incidence. For the parasite to disseminate throughout the body, it crosses the intestinal barrier, triggering inflammatory reactions. This study aimed to assess the tissue response in the ileum and colon of mice following chronic infection with T. gondii. Fourteen mice were divided into two groups: the infected group received 1000 T. gondii oocysts via gavage, and after 60 days, the mice were euthanized. The ileum and colon were collected and processed for histological analysis, inflammatory marker measurement and myenteric neuron analysis. Chronic infection resulted in a significant increase in intraepithelial lymphocytes and mast cells, as well as morphometric changes such as increased total intestinal wall thickness of the ileum, crypt depth, collagen fiber area, and a decrease in myeloperoxidase activity, without altering nitric oxide levels. While the number of myenteric neurons remained unchanged, there was an increase in vasoactive intestinal peptide expression. These results suggest persistence intestinal inflammatory stimuli in chronic T. gondii infection.
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Affiliation(s)
- Aline Aguiar
- Graduate Program in Biosciences and Pathophysiology, State University of Maringá, Maringá, Paraná, Brazil
| | | | | | - Paulo da Silva Watanabe
- Graduate Program in Biosciences and Pathophysiology, State University of Maringá, Maringá, Paraná, Brazil
| | | | - Aline Rosa Trevizan
- Graduate Program in Biosciences and Pathophysiology, State University of Maringá, Maringá, Paraná, Brazil
| | - Lainy Leiny de Lima
- Graduate Program in Biosciences and Pathophysiology, State University of Maringá, Maringá, Paraná, Brazil
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3
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Szabo EK, Bowhay C, Forrester E, Liu H, Dong B, Coria AL, Perera S, Fung B, Badawadagi N, Gaio C, Bailey K, Ritz M, Bowron J, Ariyaratne A, Finney CAM. Heligmosomoides bakeri and Toxoplasma gondii co-infection leads to increased mortality associated with changes in immune resistance in the lymphoid compartment and disease pathology. PLoS One 2024; 19:e0292408. [PMID: 38950025 PMCID: PMC11216590 DOI: 10.1371/journal.pone.0292408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Accepted: 03/14/2024] [Indexed: 07/03/2024] Open
Abstract
Co-infections are a common reality but understanding how the immune system responds in this context is complex and can be unpredictable. Heligmosomoides bakeri (parasitic roundworm, previously Heligmosomoides polygyrus) and Toxoplasma gondii (protozoan parasite) are well studied organisms that stimulate a characteristic Th2 and Th1 response, respectively. Several studies have demonstrated reduced inflammatory cytokine responses in animals co-infected with such organisms. However, while general cytokine signatures have been examined, the impact of the different cytokine producing lymphocytes on parasite control/clearance is not fully understood. We investigated five different lymphocyte populations (NK, NKT, γδ T, CD4+ T and CD8+ T cells), five organs (small intestine, Peyer's patches, mesenteric lymph nodes, spleen and liver), and 4 cytokines (IFN©, IL-4, IL-10 and IL-13) at two different time points (days 5 and 10 post T. gondii infection). We found that co-infected animals had significantly higher mortality than either single infection. This was accompanied by transient and local changes in parasite loads and cytokine profiles. Despite the early changes in lymphocyte and cytokine profiles, severe intestinal pathology in co-infected mice likely contributed to early mortality due to significant damage by both parasites in the small intestine. Our work demonstrates the importance of taking a broad view during infection research, studying multiple cell types, organs/tissues and time points to link and/or uncouple immunological from pathological findings. Our results provide insights into how co-infection with parasites stimulating different arms of the immune system can lead to drastic changes in infection dynamics.
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Affiliation(s)
- Edina K. Szabo
- Department of Biological Sciences, Faculty of Science, University of Calgary, Calgary, Alberta, Canada
- Host-Parasite Interactions Research Training Network, University of Calgary, Calgary, Alberta, Canada
| | - Christina Bowhay
- Department of Biological Sciences, Faculty of Science, University of Calgary, Calgary, Alberta, Canada
- Host-Parasite Interactions Research Training Network, University of Calgary, Calgary, Alberta, Canada
| | - Emma Forrester
- Department of Biological Sciences, Faculty of Science, University of Calgary, Calgary, Alberta, Canada
- Host-Parasite Interactions Research Training Network, University of Calgary, Calgary, Alberta, Canada
| | - Holly Liu
- Department of Biological Sciences, Faculty of Science, University of Calgary, Calgary, Alberta, Canada
- Host-Parasite Interactions Research Training Network, University of Calgary, Calgary, Alberta, Canada
| | - Beverly Dong
- Department of Biological Sciences, Faculty of Science, University of Calgary, Calgary, Alberta, Canada
- Host-Parasite Interactions Research Training Network, University of Calgary, Calgary, Alberta, Canada
| | - Aralia Leon Coria
- Department of Biological Sciences, Faculty of Science, University of Calgary, Calgary, Alberta, Canada
- Host-Parasite Interactions Research Training Network, University of Calgary, Calgary, Alberta, Canada
| | - Shashini Perera
- Department of Biological Sciences, Faculty of Science, University of Calgary, Calgary, Alberta, Canada
- Host-Parasite Interactions Research Training Network, University of Calgary, Calgary, Alberta, Canada
| | - Beatrice Fung
- Department of Biological Sciences, Faculty of Science, University of Calgary, Calgary, Alberta, Canada
- Host-Parasite Interactions Research Training Network, University of Calgary, Calgary, Alberta, Canada
| | - Namratha Badawadagi
- Department of Biological Sciences, Faculty of Science, University of Calgary, Calgary, Alberta, Canada
- Host-Parasite Interactions Research Training Network, University of Calgary, Calgary, Alberta, Canada
| | - Camila Gaio
- Department of Biological Sciences, Faculty of Science, University of Calgary, Calgary, Alberta, Canada
- Host-Parasite Interactions Research Training Network, University of Calgary, Calgary, Alberta, Canada
| | - Kayla Bailey
- Department of Biological Sciences, Faculty of Science, University of Calgary, Calgary, Alberta, Canada
- Host-Parasite Interactions Research Training Network, University of Calgary, Calgary, Alberta, Canada
| | - Manfred Ritz
- Department of Biological Sciences, Faculty of Science, University of Calgary, Calgary, Alberta, Canada
- Host-Parasite Interactions Research Training Network, University of Calgary, Calgary, Alberta, Canada
| | - Joel Bowron
- Department of Biological Sciences, Faculty of Science, University of Calgary, Calgary, Alberta, Canada
- Host-Parasite Interactions Research Training Network, University of Calgary, Calgary, Alberta, Canada
| | - Anupama Ariyaratne
- Department of Biological Sciences, Faculty of Science, University of Calgary, Calgary, Alberta, Canada
- Host-Parasite Interactions Research Training Network, University of Calgary, Calgary, Alberta, Canada
| | - Constance A. M. Finney
- Department of Biological Sciences, Faculty of Science, University of Calgary, Calgary, Alberta, Canada
- Host-Parasite Interactions Research Training Network, University of Calgary, Calgary, Alberta, Canada
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4
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Hryckowian ND, Zinda C, Park SC, Kelty MT, Knoll LJ. Host cell-specific metabolism of linoleic acid controls Toxoplasma gondii growth in cell culture. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.22.586332. [PMID: 38562845 PMCID: PMC10983968 DOI: 10.1101/2024.03.22.586332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
The obligate intracellular parasite Toxoplasma gondii can infect and replicate in any warm-blooded cell tested to date, but much of our knowledge about T. gondii cell biology comes from just one host cell type: human foreskin fibroblasts (HFFs). To expand our knowledge of host-parasite lipid interactions, we studied T. gondii in intestinal epithelial cells, the first site of host-parasite contact following oral infection and the exclusive site of parasite sexual development in feline hosts. We found that highly metabolic Caco-2 cells are permissive to T. gondii growth even when treated with high levels of linoleic acid (LA), a polyunsaturated fatty acid (PUFA) that kills parasites in HFFs. Caco-2 cells appear to sequester LA away from the parasite, preventing membrane disruptions and lipotoxicity that characterize LA-induced parasite death in HFFs. Our work is an important step toward understanding host-parasite interactions in feline intestinal epithelial cells, an understudied but important cell type in the T. gondii life cycle.
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Affiliation(s)
- Nicole D. Hryckowian
- Department of Medical Microbiology & Immunology, University of Wisconsin-Madison, Madison, WI, USA
| | - Caitlin Zinda
- Department of Medical Microbiology & Immunology, University of Wisconsin-Madison, Madison, WI, USA
| | - Sung Chul Park
- Department of Medical Microbiology & Immunology, University of Wisconsin-Madison, Madison, WI, USA
| | - Martin T. Kelty
- Department of Medical Microbiology & Immunology, University of Wisconsin-Madison, Madison, WI, USA
| | - Laura J. Knoll
- Department of Medical Microbiology & Immunology, University of Wisconsin-Madison, Madison, WI, USA
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5
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Macedo IS, Lara FA, Barbosa HS, Saraiva EM, Menna-Barreto RFS, Mariante RM. Human neutrophil extracellular traps do not impair in vitro Toxoplasma gondii infection. Front Immunol 2023; 14:1282278. [PMID: 38115994 PMCID: PMC10728484 DOI: 10.3389/fimmu.2023.1282278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Accepted: 11/20/2023] [Indexed: 12/21/2023] Open
Abstract
Introduction Toxoplasma gondii, responsible for causing toxoplasmosis, is a prevalent food and waterborne pathogen worldwide. It commonly infects warm-blooded animals and affects more than a third of the global human population. Once ingested, the parasite enters the host's small intestine and rapidly disseminates throughout the body via the bloodstream, infiltrating various tissues. Leukocyte-driven responses are vital against T. gondii, with neutrophils playing a dual role: swiftly recruited to infection sites, releasing inflammatory mediators, and serving as a replication hub and Trojan horses, aiding parasite spread. Neutrophils from various hosts release extracellular traps (NETs) against the protozoan. However, gaps persist regarding the mechanisms of NETs production to parasite and their significance in infection control. This study investigates the interplay between human neutrophils and T. gondii, exploring dynamics, key molecules, and signaling pathways involved in NETs production upon protozoan challenge. Methods and Results Using confocal and electron microscopy, live cell imaging, pharmacological inhibitors, and DNA quantification assays, we find that human neutrophils promptly release both classical and rapid NETs upon pathogen stimulation. The NETs structure exhibits diverse phenotypes over time and is consistently associated with microorganisms. Mechanisms involve neutrophil elastase and peptidylarginine deiminase, along with intracellular calcium signaling and the PI3K pathway. Unexpectedly, human traps do not diminish viability or infectivity, but potentially aid in capturing parasites for subsequent neutrophil phagocytosis and elimination. Discussion By revealing NETs formation mechanisms and their nuanced impact on T. gondii infection dynamics, our findings contribute to broader insights into host-pathogen relationships.
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Affiliation(s)
- Isabela S. Macedo
- Laboratório de Biologia Estrutural, Instituto Oswaldo Cruz, Fiocruz, Rio de Janeiro, Brazil
| | - Flávio A. Lara
- Laboratório de Microbiologia Celular, Instituto Oswaldo Cruz, Fiocruz, Rio de Janeiro, Brazil
| | - Helene S. Barbosa
- Laboratório de Biologia Estrutural, Instituto Oswaldo Cruz, Fiocruz, Rio de Janeiro, Brazil
| | - Elvira M. Saraiva
- Laboratório de Imunobiologia das Leishmanioses, Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | | | - Rafael M. Mariante
- Laboratório de Biologia Estrutural, Instituto Oswaldo Cruz, Fiocruz, Rio de Janeiro, Brazil
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May DA, Taha F, Child MA, Ewald SE. How colonization bottlenecks, tissue niches, and transmission strategies shape protozoan infections. Trends Parasitol 2023; 39:1074-1086. [PMID: 37839913 DOI: 10.1016/j.pt.2023.09.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 09/25/2023] [Accepted: 09/25/2023] [Indexed: 10/17/2023]
Abstract
Protozoan pathogens such as Plasmodium spp., Leishmania spp., Toxoplasma gondii, and Trypanosoma spp. are often associated with high-mortality, acute and chronic diseases of global health concern. For transmission and immune evasion, protozoans have evolved diverse strategies to interact with a range of host tissue environments. These interactions are linked to disease pathology, yet our understanding of the association between parasite colonization and host homeostatic disruption is limited. Recently developed techniques for cellular barcoding have the potential to uncover the biology regulating parasite transmission, dissemination, and the stability of infection. Understanding bottlenecks to infection and the in vivo tissue niches that facilitate chronic infection and spread has the potential to reveal new aspects of parasite biology.
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Affiliation(s)
- Dana A May
- Department of Microbiology, Immunology, and Cancer Biology at the Carter Immunology Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Fatima Taha
- Department of Life Sciences, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
| | - Matthew A Child
- Department of Life Sciences, Imperial College London, South Kensington Campus, London SW7 2AZ, UK.
| | - Sarah E Ewald
- Department of Microbiology, Immunology, and Cancer Biology at the Carter Immunology Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA.
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7
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Miranda Júnior NRD, Santos AGAD, Pereira AV, Mariano IA, Guilherme ALF, Santana PDL, Beletini LDF, Evangelista FF, Nogueira-Melo GDA, Sant'Ana DDMG. Rosuvastatin enhances alterations caused by Toxoplasma gondii in the duodenum of mice. Tissue Cell 2023; 84:102194. [PMID: 37597359 DOI: 10.1016/j.tice.2023.102194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 08/04/2023] [Accepted: 08/07/2023] [Indexed: 08/21/2023]
Abstract
Infection by Toxoplasma gondii may compromise the intestinal histoarchitecture through the tissue reaction triggered by the parasite. Thus, this study evaluated whether treatment with rosuvastatin modifies duodenal changes caused by the chronic infection induced by cysts of T. gondii. For this, female Swiss mice were distributed into infected and treated group (ITG), infected group (IG), group treated with 40 mg/kg rosuvastatin (TG) and control group (CG). After 72 days of infection, the animals were euthanized, the duodenum was collected and processed for histopathological analysis. We observed an increase in immune cell infiltration in the IG, TG and ITG groups, with injury to the Brunner glands. The infection led to a reduction in collagen fibers and mast cells. Infected and treated animals showed an increase in collagen fibers, acidic mucin-producing goblet cells, intraepithelial lymphocytes and mast cells, in addition to the reduction of muscle, neutral mucin-producing and Paneth cells. While treatment with rosuvastatin alone led to increased muscle layer, proportion of neutral mucin-producing goblet cells, Paneth cells, and reduction of collagen fibers. These findings indicate that the infection and treatment caused changes in the homeostasis of the intestinal wall and treatment with rosuvastatin potentiated most parameters indicative of inflammation.
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Affiliation(s)
- Nelson Raimundo de Miranda Júnior
- Biosciences and Physiopathology Program, State University of Maringá, Maringá, Brazil; Department of Basic Health Sciences, State University of Maringá, Maringá, Brazil
| | - Amanda Gubert Alves Dos Santos
- Biosciences and Physiopathology Program, State University of Maringá, Maringá, Brazil; Department of Basic Health Sciences, State University of Maringá, Maringá, Brazil
| | - Andréia Vieira Pereira
- Biosciences and Physiopathology Program, State University of Maringá, Maringá, Brazil; Department of Basic Health Sciences, State University of Maringá, Maringá, Brazil
| | - Isabela Alessandra Mariano
- Department of Clinical Analysis and Biomedicine, State University of Maringá, Maringá, Brazil; Department of Basic Health Sciences, State University of Maringá, Maringá, Brazil
| | - Ana Lucia Falavigna Guilherme
- Health Sciences Program, State University of Maringá, Maringá, Brazil; Department of Basic Health Sciences, State University of Maringá, Maringá, Brazil
| | - Priscilla de Laet Santana
- Health Sciences Program, State University of Maringá, Maringá, Brazil; Department of Basic Health Sciences, State University of Maringá, Maringá, Brazil
| | - Lucimara de Fátima Beletini
- Health Sciences Program, State University of Maringá, Maringá, Brazil; Department of Basic Health Sciences, State University of Maringá, Maringá, Brazil
| | - Fernanda Ferreira Evangelista
- Health Sciences Program, State University of Maringá, Maringá, Brazil; Department of Basic Health Sciences, State University of Maringá, Maringá, Brazil
| | - Gessilda de Alcantara Nogueira-Melo
- Biosciences and Physiopathology Program, State University of Maringá, Maringá, Brazil; Department of Basic Health Sciences, State University of Maringá, Maringá, Brazil
| | - Debora de Mello Gonçales Sant'Ana
- Biosciences and Physiopathology Program, State University of Maringá, Maringá, Brazil; Department of Basic Health Sciences, State University of Maringá, Maringá, Brazil.
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8
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Sena F, Cancela S, Bollati-Fogolín M, Pagotto R, Francia ME. Exploring Toxoplasma gondii´s Biology within the Intestinal Epithelium: intestinal-derived models to unravel sexual differentiation. Front Cell Infect Microbiol 2023; 13:1134471. [PMID: 37313339 PMCID: PMC10258352 DOI: 10.3389/fcimb.2023.1134471] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Accepted: 04/25/2023] [Indexed: 06/15/2023] Open
Abstract
A variety of intestinal-derived culture systems have been developed to mimic in vivo cell behavior and organization, incorporating different tissue and microenvironmental elements. Great insight into the biology of the causative agent of toxoplasmosis, Toxoplasma gondii, has been attained by using diverse in vitro cellular models. Nonetheless, there are still processes key to its transmission and persistence which remain to be elucidated, such as the mechanisms underlying its systemic dissemination and sexual differentiation both of which occur at the intestinal level. Because this event occurs in a complex and specific cellular environment (the intestine upon ingestion of infective forms, and the feline intestine, respectively), traditional reductionist in vitro cellular models fail to recreate conditions resembling in vivo physiology. The development of new biomaterials and the advances in cell culture knowledge have opened the door to a next generation of more physiologically relevant cellular models. Among them, organoids have become a valuable tool for unmasking the underlying mechanism involved in T. gondii sexual differentiation. Murine-derived intestinal organoids mimicking the biochemistry of the feline intestine have allowed the generation of pre-sexual and sexual stages of T. gondii for the first time in vitro, opening a window of opportunity to tackling these stages by "felinizing" a wide variety of animal cell cultures. Here, we reviewed intestinal in vitro and ex vivo models and discussed their strengths and limitations in the context of a quest for faithful models to in vitro emulate the biology of the enteric stages of T. gondii.
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Affiliation(s)
- Florencia Sena
- Laboratory of Apicomplexan Biology, Institut Pasteur Montevideo, Montevideo, Uruguay
- Laboratorio de Bioquímica, Departamento de Biología Vegetal, Universidad de la República, Montevideo, Uruguay
| | - Saira Cancela
- Cell Biology Unit, Institut Pasteur Montevideo, Montevideo, Uruguay
- Molecular, Cellular, and Animal Technology Program (ProTeMCA), Institut Pasteur Montevideo, Montevideo, Uruguay
| | - Mariela Bollati-Fogolín
- Cell Biology Unit, Institut Pasteur Montevideo, Montevideo, Uruguay
- Molecular, Cellular, and Animal Technology Program (ProTeMCA), Institut Pasteur Montevideo, Montevideo, Uruguay
| | - Romina Pagotto
- Cell Biology Unit, Institut Pasteur Montevideo, Montevideo, Uruguay
| | - María E. Francia
- Laboratory of Apicomplexan Biology, Institut Pasteur Montevideo, Montevideo, Uruguay
- Departamento de Parasitología y Micología, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
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9
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Effects of Ovine Monocyte-Derived Macrophage Infection by Recently Isolated Toxoplasma gondii Strains Showing Different Phenotypic Traits. Animals (Basel) 2022; 12:ani12243453. [PMID: 36552372 PMCID: PMC9774764 DOI: 10.3390/ani12243453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 11/28/2022] [Accepted: 12/02/2022] [Indexed: 12/14/2022] Open
Abstract
Ovine toxoplasmosis is one the most relevant reproductive diseases in sheep. The genetic variability among different Toxoplasma gondii isolates is known to be related to different degrees of virulence in mice and humans, but little is known regarding its potential effects in sheep. The aim of this study was to investigate the effect of genetic variability (types II (ToxoDB #1 and #3) and III (#2)) of six recently isolated strains that showed different phenotypic traits both in a normalized mouse model and in ovine trophoblasts, in ovine monocyte-derived macrophages and the subsequent transcript expression of cytokines and iNOS (inducible nitric oxide synthase). The type III isolate (TgShSp24) showed the highest rate of internalization, followed by the type II clonal isolate (TgShSp2), while the type II PRU isolates (TgShSp1, TgShSp3, TgShSp11 and TgShSp16) showed the lowest rates. The type II PRU strains, isolated from abortions, exhibited higher levels of anti-inflammatory cytokines and iNOS than those obtained from the myocardium of chronically infected sheep (type II PRU strains and type III), which had higher levels of pro-inflammatory cytokines. The present results show the existence of significant intra- and inter-genotypic differences in the parasite-macrophage relationship that need to be confirmed in in vivo experiments.
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10
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Ten Hoeve AL, Braun L, Rodriguez ME, Olivera GC, Bougdour A, Belmudes L, Couté Y, Saeij JPJ, Hakimi MA, Barragan A. The Toxoplasma effector GRA28 promotes parasite dissemination by inducing dendritic cell-like migratory properties in infected macrophages. Cell Host Microbe 2022; 30:1570-1588.e7. [PMID: 36309013 PMCID: PMC9710525 DOI: 10.1016/j.chom.2022.10.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 08/26/2022] [Accepted: 10/03/2022] [Indexed: 11/03/2022]
Abstract
Upon pathogen detection, macrophages normally stay sessile in tissues while dendritic cells (DCs) migrate to secondary lymphoid tissues. The obligate intracellular protozoan Toxoplasma gondii exploits the trafficking of mononuclear phagocytes for dissemination via unclear mechanisms. We report that, upon T. gondii infection, macrophages initiate the expression of transcription factors normally attributed to DCs, upregulate CCR7 expression with a chemotactic response, and perform systemic migration when adoptively transferred into mice. We show that parasite effector GRA28, released by the MYR1 secretory pathway, cooperates with host chromatin remodelers in the host cell nucleus to drive the chemotactic migration of parasitized macrophages. During in vivo challenge studies, bone marrow-derived macrophages infected with wild-type T. gondii outcompeted those challenged with MYR1- or GRA28-deficient strains in migrating and reaching secondary organs. This work reveals how an intracellular parasite hijacks chemotaxis in phagocytes and highlights a remarkable migratory plasticity in differentiated cells of the mononuclear phagocyte system.
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Affiliation(s)
- Arne L Ten Hoeve
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 106 91 Stockholm, Sweden
| | - Laurence Braun
- Institute for Advanced Biosciences, INSERM U1209, CNRS UMR5309, Université Grenoble Alpes, Grenoble, France
| | - Matias E Rodriguez
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 106 91 Stockholm, Sweden
| | - Gabriela C Olivera
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 106 91 Stockholm, Sweden
| | - Alexandre Bougdour
- Institute for Advanced Biosciences, INSERM U1209, CNRS UMR5309, Université Grenoble Alpes, Grenoble, France
| | - Lucid Belmudes
- Univ. Grenoble Alpes, INSERM, CEA, UMR BioSanté U1292, CNRS, CEA, FR2048, 38000 Grenoble, France
| | - Yohann Couté
- Univ. Grenoble Alpes, INSERM, CEA, UMR BioSanté U1292, CNRS, CEA, FR2048, 38000 Grenoble, France
| | - Jeroen P J Saeij
- Department of Pathology, Microbiology, and Immunology, University of California Davis, Davis, CA 95616, USA
| | - Mohamed-Ali Hakimi
- Institute for Advanced Biosciences, INSERM U1209, CNRS UMR5309, Université Grenoble Alpes, Grenoble, France.
| | - Antonio Barragan
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 106 91 Stockholm, Sweden.
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11
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Sardinha-Silva A, Alves-Ferreira EVC, Grigg ME. Intestinal immune responses to commensal and pathogenic protozoa. Front Immunol 2022; 13:963723. [PMID: 36211380 PMCID: PMC9533738 DOI: 10.3389/fimmu.2022.963723] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 08/15/2022] [Indexed: 11/17/2022] Open
Abstract
The physical barrier of the intestine and associated mucosal immunity maintains a delicate homeostatic balance between the host and the external environment by regulating immune responses to commensals, as well as functioning as the first line of defense against pathogenic microorganisms. Understanding the orchestration and characteristics of the intestinal mucosal immune response during commensal or pathological conditions may provide novel insights into the mechanisms underlying microbe-induced immunological tolerance, protection, and/or pathogenesis. Over the last decade, our knowledge about the interface between the host intestinal mucosa and the gut microbiome has been dominated by studies focused on bacterial communities, helminth parasites, and intestinal viruses. In contrast, specifically how commensal and pathogenic protozoa regulate intestinal immunity is less well studied. In this review, we provide an overview of mucosal immune responses induced by intestinal protozoa, with a major focus on the role of different cell types and immune mediators triggered by commensal (Blastocystis spp. and Tritrichomonas spp.) and pathogenic (Toxoplasma gondii, Giardia intestinalis, Cryptosporidium parvum) protozoa. We will discuss how these various protozoa modulate innate and adaptive immune responses induced in experimental models of infection that benefit or harm the host.
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12
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Histopathological, Immunohistochemical and Biochemical Studies of Murine Hepatosplenic Tissues Affected by Chronic Toxoplasmosis. J Parasitol Res 2022; 2022:2165205. [PMID: 35755604 PMCID: PMC9225867 DOI: 10.1155/2022/2165205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 05/17/2022] [Accepted: 05/23/2022] [Indexed: 11/17/2022] Open
Abstract
Toxoplasmosis is a serious health problem in humans and animals resulting from obligatory intracellular invasion of reticuloendothelial tissue by Toxoplasma gondii. The profound pathologic effect of toxoplasmosis is confined to nervous tissue, but many other organs, including the liver and spleen, are insulted. Many molecules like caspase-3, CD3, and CD138 are implicated in the tissue immune response in a trial to alleviate hazardous toxoplasmosis impact. This study aimed to investigate the effect of chronic toxoplasmosis on the liver and spleen tissues of mice using biochemical and histopathological techniques and to detect the activity and level of expression of caspase-3, CD3, and CD138 in these tissues using immunohistochemical labeling. Compared with normal control, altered normal histological features accompanied by inflammatory reaction were recorded in hepatosplenic reticuloendothelial tissues in chronically infected mice. The biochemical profile of the liver has been changed in the form of increased liver enzymes, and oxidative stress has been evidenced by elevated nitric oxide (NO) concentration in liver homogenate. The levels of caspase3, CD3, and CD138 were markedly expressed in the liver and spleen of infected mice. Our findings revealed the persistent effect of latent toxoplasmosis on the host's histological architecture, metabolic, and immunological profile, creating a continued challenging host-parasite relationship.
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13
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Humayun M, Ayuso JM, Park KY, Martorelli Di Genova B, Skala MC, Kerr SC, Knoll LJ, Beebe DJ. Innate immune cell response to host-parasite interaction in a human intestinal tissue microphysiological system. SCIENCE ADVANCES 2022; 8:eabm8012. [PMID: 35544643 PMCID: PMC9075809 DOI: 10.1126/sciadv.abm8012] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 03/23/2022] [Indexed: 05/03/2023]
Abstract
Protozoan parasites that infect humans are widespread and lead to varied clinical manifestations, including life-threatening illnesses in immunocompromised individuals. Animal models have provided insight into innate immunity against parasitic infections; however, species-specific differences and complexity of innate immune responses make translation to humans challenging. Thus, there is a need for in vitro systems that can elucidate mechanisms of immune control and parasite dissemination. We have developed a human microphysiological system of intestinal tissue to evaluate parasite-immune-specific interactions during infection, which integrates primary intestinal epithelial cells and immune cells to investigate the role of innate immune cells during epithelial infection by the protozoan parasite, Toxoplasma gondii, which affects billions of people worldwide. Our data indicate that epithelial infection by parasites stimulates a broad range of effector functions in neutrophils and natural killer cell-mediated cytokine production that play immunomodulatory roles, demonstrating the potential of our system for advancing the study of human-parasite interactions.
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Affiliation(s)
- Mouhita Humayun
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, USA
| | - Jose M. Ayuso
- Department of Pathology and Laboratory Medicine, University of Wisconsin-Madison, Madison, WI, USA
- Morgridge Institute for Research, University of Wisconsin-Madison, Madison, WI, USA
- Department of Dermatology, University of Wisconsin-Madison, Madison, WI, USA
| | - Keon Young Park
- Department of Surgery, University of Wisconsin-Madison, Madison, WI, USA
- Carbone Cancer Center, University of Wisconsin-Madison, Madison, WI, USA
| | | | - Melissa C. Skala
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, USA
- Morgridge Institute for Research, University of Wisconsin-Madison, Madison, WI, USA
| | - Sheena C. Kerr
- Department of Pathology and Laboratory Medicine, University of Wisconsin-Madison, Madison, WI, USA
- Carbone Cancer Center, University of Wisconsin-Madison, Madison, WI, USA
| | - Laura J. Knoll
- Carbone Cancer Center, University of Wisconsin-Madison, Madison, WI, USA
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI, USA
| | - David J. Beebe
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, USA
- Department of Pathology and Laboratory Medicine, University of Wisconsin-Madison, Madison, WI, USA
- Carbone Cancer Center, University of Wisconsin-Madison, Madison, WI, USA
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14
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El-Sayad M, Abdel Rahman M, Hussein N, Abdel Aziz R, El-Taweel HA, Abd El-Latif N. microRNA-155 Expression and Butyrylcholinesterase Activity in the Liver Tissue of Mice Infected with Toxoplasma gondii (Avirulent and Virulent Strains). Acta Parasitol 2021; 66:1167-1176. [PMID: 33840057 DOI: 10.1007/s11686-021-00383-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Accepted: 03/23/2021] [Indexed: 02/07/2023]
Abstract
PURPOSE Toxoplasma gondii is an apicomplexan parasite that exhibits distinct strain-related virulence patterns in mice. It can induce hepatic inflammation. The present study investigated MicroRNA-155 (miRNA-155) expression and butyrylcholinesterase (BChE) activity in the liver tissue of mice infected with virulent and avirulent strains of T. gondii. METHODS Mice groups included: Group (A), uninfected controls; Group (B), infected with T. gondii avirulent strain (ME-49) and euthanized 7, 27, 47, or 67 days post-infection (pi); Group (C), infected by T. gondii virulent strain (RH) and euthanized 7 days pi; and Group (D), infected by T. gondii virulent strain (RH), treated 24 h pi with sulfamethoxazole-trimethoprim (150 mg/Kg/day and 30 mg/Kg/day, respectively) and euthanized 5, 10, or 20 days pi. miRNA-155 expression was estimated in the liver tissue using the reverse transcription real-time polymerase chain reaction and the ΔΔCt method. BChE activity was estimated in liver homogenates by Ellman's colorimetric method. Liver sections were examined histopathologically. RESULTS revealed a significant elevation in miRNA-155 expression and a significant reduction of BChE activity in all the infected untreated groups compared to the uninfected mice. In group B, the maximum upregulation of miRNA-155 expression and the least reduction in BChE activity were detected 7 days pi. In group D, complete restoration of normal levels occurred 20 days pi. Liver sections showed distinct histopathological patterns with detection of intracellular tachyzoites in group B. CONCLUSION miRNA-155 and BChE play a role in regulating host-parasite interaction in toxoplasmosis and may contribute to the pathogenesis of T. gondii induced hepatic damage.
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Affiliation(s)
- Mona El-Sayad
- Department of Parasitology, Medical Research Institute, Alexandria University, Alexandria, Egypt
| | | | - Neveen Hussein
- Department of Applied Medical Chemistry. Medical Research Institute, Alexandria University, Alexandria, Egypt
| | - Rawda Abdel Aziz
- Department of Applied Medical Chemistry. Medical Research Institute, Alexandria University, Alexandria, Egypt
| | - Hend A El-Taweel
- Department of Parasitology, Medical Research Institute, Alexandria University, Alexandria, Egypt.
| | - Naglaa Abd El-Latif
- Department of Parasitology, Medical Research Institute, Alexandria University, Alexandria, Egypt
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15
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Lin CH, Chen MC, Lin LL, Christian DA, Min B, Hunter CA, Lu LF. Gut epithelial IL-27 confers intestinal immunity through the induction of intraepithelial lymphocytes. J Exp Med 2021; 218:212659. [PMID: 34554189 PMCID: PMC8480671 DOI: 10.1084/jem.20210021] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 08/03/2021] [Accepted: 09/14/2021] [Indexed: 11/04/2022] Open
Abstract
IL-27 controls a diverse range of immune responses in many disease settings. Here, we identify intestinal epithelial cells (IECs) as one of the major IL-27 cellular sources in the gut-associated tissue. Unlike IL-27 secreted by innate immune cells, gut epithelial IL-27 is dispensable for T-bet+ regulatory T cell (T reg cell) differentiation or IL-10 induction. Rather, IEC-derived IL-27 specifically promotes a distinct CD8αα+CD4+ intraepithelial lymphocyte (IEL) population that acquires their functional differentiation at the intestinal epithelium. Loss of IL-27 in IECs leads to a selective defect in CD8αα+CD4+ IELs over time. Consequently, mice with IEC-specific IL-27 ablation exhibited elevated pathogen burden during parasitic infection, and this could be rescued by transfer of exogenous CD8αα+CD4+ IELs. Collectively, our data reveal that in addition to its known regulatory properties in preventing immune hyperactivity, gut epithelial IL-27 confers barrier immunity by inducing a specific IEL subset and further suggest that IL-27 produced by different cell types plays distinct roles in maintaining intestinal homeostasis.
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Affiliation(s)
- Chia-Hao Lin
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA
| | - Mei-Chi Chen
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA
| | - Ling-Li Lin
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA
| | - David A Christian
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA
| | - Booki Min
- Department of Microbiology-Immunology, Northwestern University Feinberg School of Medicine, Chicago, IL
| | - Christopher A Hunter
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA
| | - Li-Fan Lu
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA.,Moores Cancer Center, University of California, San Diego, La Jolla, CA.,Center for Microbiome Innovation, University of California, San Diego, La Jolla, CA
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16
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Releasing latent Toxoplasma gondii cysts from host cells to the extracellular environment induces excystation. Int J Parasitol 2021; 51:999-1006. [PMID: 34081969 DOI: 10.1016/j.ijpara.2021.04.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 04/13/2021] [Accepted: 04/16/2021] [Indexed: 11/21/2022]
Abstract
Toxoplasma gondii, an obligate intracellular protozoan parasite, infects a wide variety of mammals and birds. Although T. gondii infects the brain and muscles in its latent cyst form containing bradyzoite stage parasites during chronic infection, when a chronically infected host becomes immunodeficient or is preyed upon by a predator, the latent cyst undergoes excystation. However, it is not yet known how T. gondii recognises the triggers of excystation in the microenvironment surrounding the cyst. In this study, we incubated T. gondii cysts from host cells in several solutions containing a variety of ionic compositions. Excystation occurred in a solution with an ionic composition which mimicked that of the extracellular environment. However, excystation did not occur in a solution that mimicked the intracellular environment. We also found that the specific Na+/K+ ratio and the presence of Ca2+, mimicking the extracellular environment, are required to trigger excystation. To examine whether the stage conversion of bradyzoite to tachyzoite occurs prior to egress, we constructed a gene-modified T. gondii strain expressing a green fluorescent protein specifically in the tachyzoite stage. During the process of cyst reactivation of this strain, green fluorescence was detected prior to excystation. This suggests that stage conversion from bradyzoite to tachyzoite occurs prior to cyst disruption. These results indicate that T. gondii bradyzoites monitor the ionic composition of their surroundings to recognise their expulsion from host cells, to effectively time their excystation and stage conversion.
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17
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RIPK3 Facilitates Host Resistance to Oral Toxoplasma gondii Infection. Infect Immun 2021; 89:IAI.00021-21. [PMID: 33526566 PMCID: PMC8091083 DOI: 10.1128/iai.00021-21] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Accepted: 01/25/2021] [Indexed: 12/16/2022] Open
Abstract
Toxoplasma gondii infection activates pattern recognition receptor (PRR) pathways that drive innate inflammatory responses to control infection. Necroptosis is a proinflammatory cell death pathway apart from the innate immune response that has evolved to control pathogenic infection. In this study, we further defined the role of Z-DNA binding protein 1 (ZBP1) as a PRR and assessed its contribution to necroptosis as a host protection mechanism to T. gondii infection. We found that ZBP1 does not induce proinflammatory necroptosis cell death, and ZBP1 null mice have reduced survival after oral T. gondii infection. In contrast, mice deleted in receptor-interacting serine/threonine-protein kinase 3 (RIPK3-/-), a central mediator of necroptosis, have significantly improved survival after oral T. gondii infection without a reduction in parasite burden. The physiological consequences of RIPK3 activity did not show any differences in intestine villus immunopathology, but RIPK3-/- mice showed higher immune cell infiltration and edema in the lamina propria. The contribution of necroptosis to host survival was clarified with mixed-lineage kinase domain-like pseudokinase null (MLKL-/-) mice. We found MLKL-/- mice succumbed to oral T. gondii infection the same as wild-type mice, indicating necroptosis-independent RIPK3 activity impacts host survival. These results provide new insights on the impacts of proinflammatory cell death pathways as a mechanism of host defense to oral T. gondii infection.
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18
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Holthaus D, Delgado-Betancourt E, Aebischer T, Seeber F, Klotz C. Harmonization of Protocols for Multi-Species Organoid Platforms to Study the Intestinal Biology of Toxoplasma gondii and Other Protozoan Infections. Front Cell Infect Microbiol 2021; 10:610368. [PMID: 33692963 PMCID: PMC7937733 DOI: 10.3389/fcimb.2020.610368] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 12/30/2020] [Indexed: 12/20/2022] Open
Abstract
The small intestinal epithelium is the primary route of infection for many protozoan parasites. Understanding the mechanisms of infection, however, has been hindered due to the lack of appropriate models that recapitulate the complexity of the intestinal epithelium. Here, we describe an in vitro platform using stem cell-derived intestinal organoids established for four species that are important hosts of Apicomplexa and other protozoa in a zoonotic context: human, mouse, pig and chicken. The focus was set to create organoid-derived monolayers (ODMs) using the transwell system amenable for infection studies, and we provide straightforward guidelines for their generation and differentiation from organ-derived intestinal crypts. To this end, we reduced medium variations to an absolute minimum, allowing generation and differentiation of three-dimensional organoids for all four species and the subsequent generation of ODMs. Quantitative RT-PCR, immunolabeling with antibodies against marker proteins as well as transepithelial-electrical resistance (TEER) measurements were used to characterize ODM's integrity and functional state. These experiments show an overall uniform generation of monolayers suitable for Toxoplasma gondii infection, although robustness in terms of generation of stable TEER levels and cell differentiation status varies from species to species. Murine duodenal ODMs were then infected with T. gondii and/or Giardia duodenalis, two parasites that temporarily co-inhabit the intestinal niche but have not been studied previously in cellular co-infection models. T. gondii alone did not alter TEER values, integrity and transcriptional abundance of tight junction components. In contrast, in G. duodenalis-infected ODMs all these parameters were altered and T. gondii had no apparent influence on the G. duodenalis-triggered phenotype. In conclusion, we provide robust protocols for the generation, differentiation and characterization of intestinal organoids and ODMs from four species. We show their applications for comparative studies on parasite-host interactions during the early phase of a T. gondii infection but also its use for co-infections with other relevant intestinal protozoans.
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Affiliation(s)
| | | | | | | | - Christian Klotz
- FG 16: Mycotic and Parasitic Agents and Mycobacteria, Robert Koch-Institute, Berlin, Germany
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19
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Lima TS, Mallya S, Jankeel A, Messaoudi I, Lodoen MB. Toxoplasma gondii Extends the Life Span of Infected Human Neutrophils by Inducing Cytosolic PCNA and Blocking Activation of Apoptotic Caspases. mBio 2021; 12:e02031-20. [PMID: 33500339 PMCID: PMC7858050 DOI: 10.1128/mbio.02031-20] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Accepted: 12/01/2020] [Indexed: 11/20/2022] Open
Abstract
Toxoplasma gondii is an intracellular protozoan parasite that has the remarkable ability to infect and replicate in neutrophils, immune cells with an arsenal of antimicrobial effector mechanisms. We report that T. gondii infection extends the life span of primary human peripheral blood neutrophils by delaying spontaneous apoptosis, serum starvation-induced apoptosis, and tumor necrosis alpha (TNF-α)-mediated apoptosis. T. gondii blockade of apoptosis was associated with an inhibition of processing and activation of the apoptotic caspases caspase-8 and -3, decreased phosphatidylserine exposure on the plasma membrane, and reduced cell death. We performed a global transcriptome analysis of T. gondii-infected peripheral blood neutrophils using RNA sequencing (RNA-Seq) and identified gene expression changes associated with DNA replication and DNA repair pathways, which in mature neutrophils are indicative of changes in regulators of cell survival. Consistent with the RNA-Seq data, T. gondii infection upregulated transcript and protein expression of PCNA, which is found in the cytosol of human neutrophils, where it functions as a key inhibitor of apoptotic pro-caspases. Infection of neutrophils resulted in increased interaction of PCNA with pro-caspase-3. Inhibition of this interaction with an AlkB homologue 2 PCNA-interacting motif (APIM) peptide reversed the infection-induced delay in cell death. Taken together, these findings indicate a novel strategy by which T. gondii manipulates cell life span in primary human neutrophils, which may allow the parasite to maintain an intracellular replicative niche and avoid immune clearance.IMPORTANCEToxoplasma gondii is an obligate intracellular parasite that can cause life-threatening disease in immunocompromised individuals and in the developing fetus. Interestingly, T. gondii has evolved strategies to successfully manipulate the host immune system to establish a productive infection and evade host defense mechanisms. Although it is well documented that neutrophils are mobilized during acute T. gondii infection and infiltrate the site of infection, these cells can also be actively infected by T. gondii and serve as a replicative niche for the parasite. However, there is a limited understanding of the molecular processes occurring within T. gondii-infected neutrophils. This study reveals that T. gondii extends the life span of human neutrophils by inducing the expression of PCNA, which prevents activation of apoptotic caspases, thus delaying apoptosis. This strategy may allow the parasite to preserve its replicative intracellular niche.
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Affiliation(s)
- Tatiane S Lima
- Department of Molecular Biology and Biochemistry, University of California, Irvine, Irvine, California, USA
- Institute for Immunology, University of California, Irvine, Irvine, California, USA
| | - Sharmila Mallya
- Department of Molecular Biology and Biochemistry, University of California, Irvine, Irvine, California, USA
- Institute for Immunology, University of California, Irvine, Irvine, California, USA
| | - Allen Jankeel
- Department of Molecular Biology and Biochemistry, University of California, Irvine, Irvine, California, USA
- Institute for Immunology, University of California, Irvine, Irvine, California, USA
| | - Ilhem Messaoudi
- Department of Molecular Biology and Biochemistry, University of California, Irvine, Irvine, California, USA
- Institute for Immunology, University of California, Irvine, Irvine, California, USA
| | - Melissa B Lodoen
- Department of Molecular Biology and Biochemistry, University of California, Irvine, Irvine, California, USA
- Institute for Immunology, University of California, Irvine, Irvine, California, USA
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20
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Snyder LM, Denkers EY. From Initiators to Effectors: Roadmap Through the Intestine During Encounter of Toxoplasma gondii With the Mucosal Immune System. Front Cell Infect Microbiol 2021; 10:614701. [PMID: 33505924 PMCID: PMC7829212 DOI: 10.3389/fcimb.2020.614701] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Accepted: 11/24/2020] [Indexed: 12/26/2022] Open
Abstract
The gastrointestinal tract is a major portal of entry for many pathogens, including the protozoan parasite Toxoplasma gondii. Billions of people worldwide have acquired T. gondii at some point in their life, and for the vast majority this has led to latent infection in the central nervous system. The first line of host defense against Toxoplasma is located within the intestinal mucosa. Appropriate coordination of responses by the intestinal epithelium, intraepithelial lymphocytes, and lamina propria cells results in an inflammatory response that controls acute infection. Under some conditions, infection elicits bacterial dysbiosis and immune-mediated tissue damage in the intestine. Here, we discuss the complex interactions between the microbiota, the epithelium, as well as innate and adaptive immune cells in the intestinal mucosa that induce protective immunity, and that sometimes switch to inflammatory pathology as T. gondii encounters tissues of the gut.
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Affiliation(s)
- Lindsay M Snyder
- Center for Evolutionary and Theoretical Immunology and Department of Biology, University of New Mexico, Albuquerque, NM, United States
| | - Eric Y Denkers
- Center for Evolutionary and Theoretical Immunology and Department of Biology, University of New Mexico, Albuquerque, NM, United States
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21
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Afifi MA. The Parasites Caught In-Action: Imaging at the Host-Parasite Interface. J Microsc Ultrastruct 2021; 9:1-6. [PMID: 33850705 PMCID: PMC8030542 DOI: 10.4103/jmau.jmau_1_20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2020] [Revised: 01/02/2020] [Accepted: 01/21/2020] [Indexed: 11/24/2022] Open
Abstract
For many decades, scientists were unable to expose the invisible existence of the parasites in their living hosts, except by scarification and then dissection of the animal model. This process just demonstrates a dead parasite in a dead host. Using this approach, very limited information can be obtained concerning the dynamics of infection and the pathways utilized by the parasite to survive within a hostile host's environment. Introduction of ultra-high-speed imaging techniques, with a time domain of barely few microseconds or even less, has revolutionized the "in vivo dissection" of the parasites. Such methods provide platforms for imaging host-parasite interactions at diverse scales, down to the molecular level. These have complementary advantages and relative assets in investigating host-parasite interactions. Therefore, better elucidation of such interaction may require the usage of more than one approach. Precise in vivo quantification, of the parasite load within the host, and better insight into the kinetics of infection are the two main advantages of the novel imaging procedures. However, imaging parasite-host interplay is still a challenging approach due to many constraints related to the parasite biology, the tissue environment within which the parasites exist, and the logistic technical limitations. This review was planned to assist better understanding of how much the new imaging techniques impacted the recent advances in parasite biology, especially the immunobiology of protozoan parasites.
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Affiliation(s)
- Mohammed A. Afifi
- Department of Medical Microbiology and Parasitology, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
- Department of Medical Parasitology, Faculty of Medicine, Beni-Suef University, Beni-Suef, Egypt
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22
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Gossner A, Hassan MA. Transcriptional Analyses Identify Genes That Modulate Bovine Macrophage Response to Toxoplasma Infection and Immune Stimulation. Front Cell Infect Microbiol 2020; 10:437. [PMID: 33014886 PMCID: PMC7508302 DOI: 10.3389/fcimb.2020.00437] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Accepted: 07/16/2020] [Indexed: 11/26/2022] Open
Abstract
The obligate intracellular parasite, Toxoplasma gondii, is highly prevalent among livestock species. Although cattle are generally resistant to Toxoplasma strains circulating in Europe and North America, the underlying mechanisms are largely unknown. Here, we report that bovine bone marrow-derived macrophage (BMDM) pre-stimulated with interferon gamma (IFNγ) restricts intracellular Toxoplasma growth independently of nitric oxide. While Toxoplasma promoted the expression of genes associated with alternative macrophage activation and lipid metabolism, IFNγ abrogated parasite-induced transcriptional responses and promoted the expression of genes linked to the classical macrophage activation phenotype. Additionally, several chemokines, including CCL22, that are linked to parasite-induced activation of the Wnt/β-catenin signaling were highly expressed in Toxoplasma-exposed naïve BMDMs. A chemical Wnt/β-catenin signaling pathway antagonist (IWR-1-endo) significantly reduced intracellular parasite burden in naïve BMDMs, suggesting that Toxoplasma activates this pathway to evade bovine macrophage anti-parasitic responses. Congruently, intracellular burden of a mutant Toxoplasma strain (RHΔASP5) that does not secrete dense granule proteins into the host cell, which is an essential requirement for parasite-induced activation of the Wnt/β-catenin pathway, was significantly reduced in naïve BMDMs. However, both the Wnt/β-catenin antagonist and RHASPΔ5 did not abolish parasite burden differences in naïve and IFNγ-stimulated BMDMs. Finally, we observed that parasites infecting IFNγ-stimulated BMDMs largely express genes associated with the slow dividing bradyzoite stage. Overall, this study provides novel insights into bovine macrophage transcriptional response to Toxoplasma. It establishes a foundation for a mechanistic analysis IFNγ-induced bovine anti-Toxoplasma responses and the counteracting Toxoplasma survival strategies.
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Affiliation(s)
- Anton Gossner
- Division of Infection and Immunity, The Roslin Institute, The University of Edinburgh, Edinburgh, United Kingdom
| | - Musa A Hassan
- Division of Infection and Immunity, The Roslin Institute, The University of Edinburgh, Edinburgh, United Kingdom.,Centre for Tropical Livestock Genetics and Health, The University of Edinburgh, Edinburgh, United Kingdom
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23
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Hares MF, Tiffney EA, Johnston LJ, Luu L, Stewart CJ, Flynn RJ, Coombes JL. Stem cell-derived enteroid cultures as a tool for dissecting host-parasite interactions in the small intestinal epithelium. Parasite Immunol 2020; 43:e12765. [PMID: 32564379 DOI: 10.1111/pim.12765] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 06/15/2020] [Accepted: 06/16/2020] [Indexed: 12/12/2022]
Abstract
Toxoplasma gondii and Cryptosporidium spp. can cause devastating pathological effects in humans and livestock, and in particular to young or immunocompromised individuals. The current treatment plans for these enteric parasites are limited due to long drug courses, severe side effects or simply a lack of efficacy. The study of the early interactions between the parasites and the site of infection in the small intestinal epithelium has been thwarted by the lack of accessible, physiologically relevant and species-specific models. Increasingly, 3D stem cell-derived enteroid models are being refined and developed into sophisticated models of infectious disease. In this review, we shall illustrate the use of enteroids to spearhead research into enteric parasitic infections, bridging the gap between cell line cultures and in vivo experiments.
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Affiliation(s)
- Miriam F Hares
- Department of Infection Biology, Institute of Infection and Global Health, University of Liverpool, Liverpool, UK
| | - Ellen-Alana Tiffney
- Department of Infection Biology, Institute of Infection and Global Health, University of Liverpool, Liverpool, UK
| | - Luke J Johnston
- Department of Infection Biology, Institute of Infection and Global Health, University of Liverpool, Liverpool, UK
| | - Lisa Luu
- Department of Infection Biology, Institute of Infection and Global Health, University of Liverpool, Liverpool, UK
| | | | - Robin J Flynn
- Department of Infection Biology, Institute of Infection and Global Health, University of Liverpool, Liverpool, UK
| | - Janine L Coombes
- Department of Infection Biology, Institute of Infection and Global Health, University of Liverpool, Liverpool, UK
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24
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Yoshida N, Domart MC, Peddie CJ, Yakimovich A, Mazon-Moya MJ, Hawkins TA, Collinson L, Mercer J, Frickel EM, Mostowy S. The zebrafish as a novel model for the in vivo study of Toxoplasma gondii replication and interaction with macrophages. Dis Model Mech 2020; 13:dmm043091. [PMID: 32461265 PMCID: PMC7390642 DOI: 10.1242/dmm.043091] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Accepted: 05/12/2020] [Indexed: 12/21/2022] Open
Abstract
Toxoplasma gondii is an obligate intracellular parasite capable of invading any nucleated cell. Three main clonal lineages (type I, II, III) exist and murine models have driven the understanding of general and strain-specific immune mechanisms underlying Toxoplasma infection. However, murine models are limited for studying parasite-leukocyte interactions in vivo, and discrepancies exist between cellular immune responses observed in mouse versus human cells. Here, we developed a zebrafish infection model to study the innate immune response to Toxoplasma in vivo By infecting the zebrafish hindbrain ventricle, and using high-resolution microscopy techniques coupled with computer vision-driven automated image analysis, we reveal that Toxoplasma invades brain cells and replicates inside a parasitophorous vacuole to which type I and III parasites recruit host cell mitochondria. We also show that type II and III strains maintain a higher infectious burden than type I strains. To understand how parasites are cleared in vivo, we further analyzed Toxoplasma-macrophage interactions using time-lapse microscopy and three-dimensional correlative light and electron microscopy (3D CLEM). Time-lapse microscopy revealed that macrophages are recruited to the infection site and play a key role in Toxoplasma control. High-resolution 3D CLEM revealed parasitophorous vacuole breakage in brain cells and macrophages in vivo, suggesting that cell-intrinsic mechanisms may be used to destroy the intracellular niche of tachyzoites. Together, our results demonstrate in vivo control of Toxoplasma by macrophages, and highlight the possibility that zebrafish may be further exploited as a novel model system for discoveries within the field of parasite immunity.This article has an associated First Person interview with the first author of the paper.
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MESH Headings
- Animals
- Disease Models, Animal
- Host-Parasite Interactions
- Macrophages/immunology
- Macrophages/parasitology
- Macrophages/ultrastructure
- Microscopy, Confocal
- Microscopy, Electron, Scanning
- Microscopy, Fluorescence
- Microscopy, Video
- Parasite Load
- Rhombencephalon/immunology
- Rhombencephalon/microbiology
- Rhombencephalon/ultrastructure
- Time Factors
- Toxoplasma/growth & development
- Toxoplasma/immunology
- Toxoplasma/ultrastructure
- Toxoplasmosis, Animal/immunology
- Toxoplasmosis, Animal/parasitology
- Toxoplasmosis, Animal/pathology
- Toxoplasmosis, Cerebral/immunology
- Toxoplasmosis, Cerebral/parasitology
- Toxoplasmosis, Cerebral/pathology
- Zebrafish/parasitology
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Affiliation(s)
- Nagisa Yoshida
- Host-Toxoplasma Interaction Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1BF, UK
- Section of Microbiology, MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, UK
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | - Marie-Charlotte Domart
- Electron Microscopy Science Technology Platform, The Francis Crick Institute, 1 Midland Road, London NW1 1BF, UK
| | - Christopher J Peddie
- Electron Microscopy Science Technology Platform, The Francis Crick Institute, 1 Midland Road, London NW1 1BF, UK
| | - Artur Yakimovich
- MRC-Laboratory for Molecular Cell Biology, University College London, Gower Street, London, WC1E 6BT, UK
- Artificial Intelligence for Life Sciences CIC, 40 Gowers Walk, London, E1 8BH, UK
| | - Maria J Mazon-Moya
- Section of Microbiology, MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, UK
| | - Thomas A Hawkins
- Department of Cell and Developmental Biology, University College London, Gower Street, London, WC1E 6BT, UK
| | - Lucy Collinson
- Electron Microscopy Science Technology Platform, The Francis Crick Institute, 1 Midland Road, London NW1 1BF, UK
| | - Jason Mercer
- MRC-Laboratory for Molecular Cell Biology, University College London, Gower Street, London, WC1E 6BT, UK
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, B15 2TT, UK
| | - Eva-Maria Frickel
- Host-Toxoplasma Interaction Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1BF, UK
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, B15 2TT, UK
| | - Serge Mostowy
- Section of Microbiology, MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, UK
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
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25
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Zhao XY, Ewald SE. The molecular biology and immune control of chronic Toxoplasma gondii infection. J Clin Invest 2020; 130:3370-3380. [PMID: 32609097 PMCID: PMC7324197 DOI: 10.1172/jci136226] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Toxoplasma gondii is an incredibly successful parasite owing in part to its ability to persist within cells for the life of the host. Remarkably, at least 350 host species of T. gondii have been described to date, and it is estimated that 30% of the global human population is chronically infected. The importance of T. gondii in human health was made clear with the first reports of congenital toxoplasmosis in the 1940s. However, the AIDS crisis in the 1980s revealed the prevalence of chronic infection, as patients presented with reactivated chronic toxoplasmosis, underscoring the importance of an intact immune system for parasite control. In the last 40 years, there has been tremendous progress toward understanding the biology of T. gondii infection using rodent models, human cell experimental systems, and clinical data. However, there are still major holes in our understanding of T. gondii biology, including the genes controlling parasite development, the mechanisms of cell-intrinsic immunity to T. gondii in the brain and muscle, and the long-term effects of infection on host homeostasis. The need to better understand the biology of chronic infection is underscored by the recent rise in ocular disease associated with emerging haplotypes of T. gondii and our lack of effective treatments to sterilize chronic infection. This Review discusses the cell types and molecular mediators, both host and parasite, that facilitate persistent T. gondii infection. We highlight the consequences of chronic infection for tissue-specific pathology and identify open questions in this area of host-Toxoplasma interactions.
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26
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Rahman M, Devriendt B, Jennes M, Gisbert Algaba I, Dorny P, Dierick K, De Craeye S, Cox E. Early Kinetics of Intestinal Infection and Immune Responses to Two Toxoplasma gondii Strains in Pigs. Front Cell Infect Microbiol 2020; 10:161. [PMID: 32373554 PMCID: PMC7176905 DOI: 10.3389/fcimb.2020.00161] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Accepted: 03/26/2020] [Indexed: 11/28/2022] Open
Abstract
Toxoplasma gondii is an obligate intracellular parasite, able to infect all homeothermic animals mostly through ingestion of (oo)cysts contaminated food or water. Recently, we observed a T. gondii strain-specific clearance from tissues upon infection in pigs: while the swine-adapted LR strain persisted in porcine tissues, a subsequent infection with the human-isolated Gangji strain cleared parasites from several tissues. We hypothesized that intestinal immune responses shortly after infection might play a role in this strain-specific clearance. To assess this possibility, the parasite load in small intestinal lymph node cells and blood immune cells as well as the IFNγ secretion by these cells were evaluated at 2, 4, 8, 14, and 28 days post oral inoculation of pigs with tissue cysts of both strains. Interestingly, at day 4 post inoculation with the LR strain the parasite was detected by qPCR only in the duodenal lymph node cells, while in the jejunal and ileal lymph node cells and PBMCs the parasite was detected from day 8 post inoculation onwards. Although we observed a similar profile upon inoculation with the Gangji strain, the parasite load in the examined cells was much lower. This was reflected in a significantly higher T. gondii-specific serum IgG response in LR compared to Gangji infected pigs at day 28 post inoculation. Unexpectedly, this was not reflected in the IFNγ secretion upon re-stimulation of the cells where almost equal IFNγ secretion was observed in both groups. In conclusion, our results show that T. gondii first enters the host at the duodenum and then probably disseminates from this site to the other tissues. How the early immune response influences the clearance of parasite from tissues needs further study.
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Affiliation(s)
- Mizanur Rahman
- Laboratory of Immunology, Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Bert Devriendt
- Laboratory of Immunology, Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Malgorzata Jennes
- Laboratory of Immunology, Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Ignacio Gisbert Algaba
- Sciensano, National Reference Center for Toxoplasmosis, Infectious Diseases in Humans, Brussels, Belgium
| | - Pierre Dorny
- Department of Biomedical Sciences, Institute for Tropical Medicine, Antwerp, Belgium.,Laboratory of Parasitology, Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Katelijne Dierick
- Sciensano, National Reference Center for Toxoplasmosis, Infectious Diseases in Humans, Brussels, Belgium
| | - Stéphane De Craeye
- Sciensano, National Reference Center for Toxoplasmosis, Infectious Diseases in Humans, Brussels, Belgium
| | - Eric Cox
- Laboratory of Immunology, Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
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27
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Park J, Hunter CA. The role of macrophages in protective and pathological responses to Toxoplasma gondii. Parasite Immunol 2020; 42:e12712. [PMID: 32187690 DOI: 10.1111/pim.12712] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 02/12/2020] [Accepted: 02/24/2020] [Indexed: 02/06/2023]
Abstract
The ability of Toxoplasma gondii to cause clinical disease in immune-competent and immune-deficient hosts coupled with its ease of use in vitro and availability of murine models has led to its use as a model organism to study how the immune system controls an intracellular infection. This article reviews the studies that established the role of the cytokine IFN-γ in the activation of macrophages to control T gondii and the events that lead to the mobilization and expansion of macrophage populations and their ability to limit parasite replication. Macrophages also have pro-inflammatory functions that promote protective NK and T-cell activities as well as regulatory properties that facilitate the resolution of inflammation. Nevertheless, while macrophages are important in determining the outcome of infection, T gondii has evolved mechanisms to subvert macrophage activation and can utilize their migratory activities to promote dissemination and these two properties underlie the ability of this parasite to persist and cause disease.
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Affiliation(s)
- Jeongho Park
- University of Pennsylvania School of Veterinary Medicine, Philadelphia, PA, USA.,Kangwon National University College of Veterinary Medicine and Institute of Veterinary Science, Chuncheon, Korea
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28
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Drewry LL, Jones NG, Wang Q, Onken MD, Miller MJ, Sibley LD. The secreted kinase ROP17 promotes Toxoplasma gondii dissemination by hijacking monocyte tissue migration. Nat Microbiol 2019; 4:1951-1963. [PMID: 31332383 PMCID: PMC6814536 DOI: 10.1038/s41564-019-0504-8] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Accepted: 06/05/2019] [Indexed: 01/02/2023]
Abstract
The protozoan parasite Toxoplasma gondii is thought to exploit monocyte trafficking to facilitate dissemination across endothelial barriers such as the blood-brain barrier. Here we analyzed the migration of parasitized monocytes in model endothelial and interstitial environments. We report that infection enhanced monocyte locomotion on the surface of endothelial cells, but profoundly inhibited monocyte transmigration across endothelial barriers. In contrast, infection robustly increased monocyte and macrophage migration through collagen-rich tissues in a Rho/ROCK-dependent manner consistent with integrin-independent interstitial migration. We further demonstrated that the secreted T. gondii protein kinase ROP17 was required for enhanced tissue migration. In vivo, ROP17-deficient parasites failed to upregulate monocyte tissue migration and exhibited an early dissemination delay, leading to prolonged mouse survival. Our findings indicate that the parasite-induced changes in monocyte motility likely facilitate the transport of T. gondii through tissues and promote systemic dissemination, rather than shuttle parasites across the blood-brain barrier via extravasation.
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Affiliation(s)
- Lisa L Drewry
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Nathaniel G Jones
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, USA.,York Biomedical Research Institute, Department of Biology, University of York, York, UK
| | - Quiling Wang
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Michael D Onken
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO, USA
| | - Mark J Miller
- Department of Medicine, Division of Infectious Diseases, Washington University School of Medicine, St. Louis, MO, USA
| | - L David Sibley
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, USA.
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29
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Drewry LL, Sibley LD. The hitchhiker's guide to parasite dissemination. Cell Microbiol 2019; 21:e13070. [PMID: 31219666 DOI: 10.1111/cmi.13070] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Revised: 05/21/2019] [Accepted: 06/13/2019] [Indexed: 12/29/2022]
Abstract
Toxoplasma gondii (T. gondii) is a parasitic protist that can infect nearly all nucleated cell types and tissues of warm-blooded vertebrate hosts. T. gondii utilises a unique form of gliding motility to cross cellular barriers, enter tissues, and penetrate host cells, thus enhancing spread within an infected host. However, T. gondii also disseminates by hijacking the migratory abilities of infected leukocytes. Traditionally, this process has been viewed as a route to cross biological barriers such as the blood-brain barrier. Here, we review recent findings that challenge this view by showing that infection of monocytes downregulates the program of transendothelial migration. Instead, infection by T. gondii enhances Rho-dependent interstitial migration of monocytes and macrophages, which enhances dissemination within tissues. Collectively, the available evidence indicates that T. gondii parasites use multiple means to disseminate within the host, including enhanced motility in tissues and translocation across biological barriers.
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Affiliation(s)
- Lisa L Drewry
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri
| | - L David Sibley
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri
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30
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Melchor SJ, Ewald SE. Disease Tolerance in Toxoplasma Infection. Front Cell Infect Microbiol 2019; 9:185. [PMID: 31245299 PMCID: PMC6563770 DOI: 10.3389/fcimb.2019.00185] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2019] [Accepted: 05/14/2019] [Indexed: 01/12/2023] Open
Abstract
Toxoplasma gondii is a successful protozoan parasite that cycles between definitive felid hosts and a broad range of intermediate hosts, including rodents and humans. Within intermediate hosts, this obligate intracellular parasite invades the small intestine, inducing an inflammatory response. Toxoplasma infects infiltrating immune cells, using them to spread systemically and reach tissues amenable to chronic infection. An intact immune system is necessary to control life-long chronic infection. Chronic infection is characterized by formation of parasite cysts, which are necessary for survival through the gastrointestinal tract of the next host. Thus, Toxoplasma must evade sterilizing immunity, but still rely on the host's immune response for survival and transmission. To do this, Toxoplasma exploits a central cost-benefit tradeoff in immunity: the need to escalate inflammation for pathogen clearance vs. the need to limit inflammation-induced bystander damage. What are the consequences of sustained inflammation on host biology? Many studies have focused on aspects of the immune response that directly target Toxoplasma growth and survival, commonly referred to as "resistance mechanisms." However, it is becoming clear that a parallel arm of the immune response has evolved to mitigate damage caused by the parasite directly (for example, egress-induced cell death) or bystander damage due to the inflammatory response (for example, reactive nitrogen species, degranulation). These so-called "disease tolerance" mechanisms promote tissue function and host survival without directly targeting the pathogen. Here we review changes to host metabolism, tissue structure, and immune function that point to disease tolerance mechanisms during Toxoplasma infection. We explore the impact tolerance programs have on the health of the host and parasite biology.
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Affiliation(s)
| | - Sarah E. Ewald
- Department of Microbiology, Immunology and Cancer Biology and the Carter Immunology Center, University of Virginia School of Medicine, Charlottesville, VA, United States
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31
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Florimond C, Cordonnier C, Taujale R, van der Wel H, Kannan N, West CM, Blader IJ. A Toxoplasma Prolyl Hydroxylase Mediates Oxygen Stress Responses by Regulating Translation Elongation. mBio 2019; 10:e00234-19. [PMID: 30914506 PMCID: PMC6437050 DOI: 10.1128/mbio.00234-19] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2019] [Accepted: 02/08/2019] [Indexed: 02/08/2023] Open
Abstract
As the protozoan parasite Toxoplasma gondii disseminates through its host, it responds to environmental changes by altering its gene expression, metabolism, and other processes. Oxygen is one variable environmental factor, and properly adapting to changes in oxygen levels is critical to prevent the accumulation of reactive oxygen species and other cytotoxic factors. Thus, oxygen-sensing proteins are important, and among these, 2-oxoglutarate-dependent prolyl hydroxylases are highly conserved throughout evolution. Toxoplasma expresses two such enzymes, TgPHYa, which regulates the SCF-ubiquitin ligase complex, and TgPHYb. To characterize TgPHYb, we created a Toxoplasma strain that conditionally expresses TgPHYb and report that TgPHYb is required for optimal parasite growth under normal growth conditions. However, exposing TgPHYb-depleted parasites to extracellular stress leads to severe decreases in parasite invasion, which is likely due to decreased abundance of parasite adhesins. Adhesin protein abundance is reduced in TgPHYb-depleted parasites as a result of inactivation of the protein synthesis elongation factor eEF2 that is accompanied by decreased rates of translational elongation. In contrast to most other oxygen-sensing proteins that mediate cellular responses to low O2, TgPHYb is specifically required for parasite growth and protein synthesis at high, but not low, O2 tensions as well as resistance to reactive oxygen species. In vivo, reduced TgPHYb expression leads to lower parasite burdens in oxygen-rich tissues. Taken together, these data identify TgPHYb as a sensor of high O2 levels, in contrast to TgPHYa, which supports the parasite at low O2IMPORTANCE Because oxygen plays a key role in the growth of many organisms, cells must know how much oxygen is available. O2-sensing proteins are therefore critical cellular factors, and prolyl hydroxylases are the best-studied type of O2-sensing proteins. In general, prolyl hydroxylases trigger cellular responses to decreased oxygen availability. But, how does a cell react to high levels of oxygen? Using the protozoan parasite Toxoplasma gondii, we discovered a prolyl hydroxylase that allows the parasite to grow at elevated oxygen levels and does so by regulating protein synthesis. Loss of this enzyme also reduces parasite burden in oxygen-rich tissues, indicating that sensing both high and low levels of oxygen impacts the growth and physiology of Toxoplasma.
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Affiliation(s)
- Celia Florimond
- Department of Microbiology and Immunology, University at Buffalo School of Medicine, Buffalo, New York, USA
| | - Charlotte Cordonnier
- Department of Microbiology and Immunology, University at Buffalo School of Medicine, Buffalo, New York, USA
| | - Rahil Taujale
- Institute of Bioinformatics, University of Georgia, Athens, Georgia, USA
| | - Hanke van der Wel
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA
| | - Natarajan Kannan
- Institute of Bioinformatics, University of Georgia, Athens, Georgia, USA
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA
| | - Christopher M West
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, USA
| | - Ira J Blader
- Department of Microbiology and Immunology, University at Buffalo School of Medicine, Buffalo, New York, USA
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32
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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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33
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Delgado Betancourt E, Hamid B, Fabian BT, Klotz C, Hartmann S, Seeber F. From Entry to Early Dissemination- Toxoplasma gondii's Initial Encounter With Its Host. Front Cell Infect Microbiol 2019; 9:46. [PMID: 30891433 PMCID: PMC6411707 DOI: 10.3389/fcimb.2019.00046] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2018] [Accepted: 02/13/2019] [Indexed: 12/27/2022] Open
Abstract
Toxoplasma gondii is a zoonotic intracellular parasite, able to infect any warm-blooded animal via ingestion of infective stages, either contained in tissue cysts or oocysts released into the environment. While immune responses during infection are well-studied, there is still limited knowledge about the very early infection events in the gut tissue after infection via the oral route. Here we briefly discuss differences in host-specific responses following infection with oocyst-derived sporozoites vs. tissue cyst-derived bradyzoites. A focus is given to innate intestinal defense mechanisms and early immune cell events that precede T. gondii's dissemination in the host. We propose stem cell-derived intestinal organoids as a model to study early events of natural host-pathogen interaction. These offer several advantages such as live cell imaging and transcriptomic profiling of the earliest invasion processes. We additionally highlight the necessity of an appropriate large animal model reflecting human infection more closely than conventional infection models, to study the roles of dendritic cells and macrophages during early infection.
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Affiliation(s)
| | - Benjamin Hamid
- Department of Veterinary Medicine, Institute of Immunology, Freie Universität Berlin, Berlin, Germany
| | - Benedikt T Fabian
- FG 16: Mycotic and Parasitic Agents and Mycobacteria, Robert Koch-Institute, Berlin, Germany
| | - Christian Klotz
- FG 16: Mycotic and Parasitic Agents and Mycobacteria, Robert Koch-Institute, Berlin, Germany
| | - Susanne Hartmann
- Department of Veterinary Medicine, Institute of Immunology, Freie Universität Berlin, Berlin, Germany
| | - Frank Seeber
- FG 16: Mycotic and Parasitic Agents and Mycobacteria, Robert Koch-Institute, Berlin, Germany
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34
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Majumdar T, Sharma S, Kumar M, Hussain MA, Chauhan N, Kalia I, Sahu AK, Rana VS, Bharti R, Haldar AK, Singh AP, Mazumder S. Tryptophan-kynurenine pathway attenuates β-catenin-dependent pro-parasitic role of STING-TICAM2-IRF3-IDO1 signalosome in Toxoplasma gondii infection. Cell Death Dis 2019; 10:161. [PMID: 30770800 PMCID: PMC6377608 DOI: 10.1038/s41419-019-1420-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 01/25/2019] [Accepted: 01/28/2019] [Indexed: 12/11/2022]
Abstract
Recent studies have documented the diverse role of host immunity in infection by the protozoan parasite, Toxoplasma gondii. However, the contribution of the β-catenin pathway in this process has not been explored. Here, we show that AKT-mediated phosphorylated β-catenin supports T. gondii multiplication which is arrested in the deficiency of its phosphorylation domain at S552 position. The β-catenin-TCF4 protein complex binds to the promoter region of IRF3 gene and initiates its transcription, which was also abrogated in β-catenin knockout cells. TBK-independent phosphorylation of STING(S366) and its adaptor molecule TICAM2 by phospho-AKT(T308S473) augmented downstream IRF3-dependent IDO1 transcription, which was also dependent on β-catenin. But, proteasomal degradation of IDO1 by its tyrosine phosphorylation (at Y115 and Y253) favoured parasite replication. In absence of IDO1, tryptophan was catabolized into melatonin, which supressed cellular reactive oxygen species (ROS) and boosted parasite growth. Conversely, when tyrosine phosphorylation was abolished by phosphosite mutations, IDO1 escaped its ubiquitin-mediated proteasomal degradation system (UPS) and the stable IDO1 prevented parasite replication by kynurenine synthesis. We propose that T. gondii selectively utilizes tryptophan to produce the antioxidant, melatonin, thus prolonging the survival of infected cells through functional AKT and β-catenin activity for better parasite replication. Stable IDO1 in the presence of IFN-γ catabolized tryptophan into kynurenine, promoting cell death by suppressing phospho-AKT and phospho-β-catenin levels, and circumvented parasite replication. Treatment of infected cells with kynurenine or its analogue, teriflunomide suppressed kinase activity of AKT, and phosphorylation of β-catenin triggering caspase-3 dependent apoptosis of infected cells to inhibit parasite growth. Our results demonstrate that β-catenin regulate phosphorylated STING-TICAM2-IRF3-IDO1 signalosome for a cell-intrinsic pro-parasitic role. We propose that the downstream IRF3-IDO1-reliant tryptophan catabolites and their analogues can act as effective immunotherapeutic molecules to control T. gondii replication by impairing the AKT and β-catenin axis.
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Affiliation(s)
- Tanmay Majumdar
- Immunobiology Laboratory, Department of Zoology, University of Delhi, Delhi, 110007, India.
| | - Shagun Sharma
- Immunobiology Laboratory, Department of Zoology, University of Delhi, Delhi, 110007, India
| | - Manmohan Kumar
- Immunobiology Laboratory, Department of Zoology, University of Delhi, Delhi, 110007, India
| | - Md Arafat Hussain
- Immunobiology Laboratory, Department of Zoology, University of Delhi, Delhi, 110007, India
| | - Namita Chauhan
- Department of Zoology, University of Delhi, Delhi, 110007, India
| | - Inderjeet Kalia
- Infectious Diseases Laboratory, National Institute of Immunology, Aruna Asaf Ali Marg, Delhi, 110067, India
| | - Amit Kumar Sahu
- Infectious Diseases Laboratory, National Institute of Immunology, Aruna Asaf Ali Marg, Delhi, 110067, India
| | - Vipin Singh Rana
- Department of Zoology, University of Delhi, Delhi, 110007, India
| | - Ruchi Bharti
- Immunobiology Laboratory, Department of Zoology, University of Delhi, Delhi, 110007, India
| | - Arun Kumar Haldar
- Division of Biochemistry, CSIR-Central Drug Research Institute, Sector-10, Jankipuram Ext., Lucknow, 226031, India
| | - Agam P Singh
- Infectious Diseases Laboratory, National Institute of Immunology, Aruna Asaf Ali Marg, Delhi, 110067, India
| | - Shibnath Mazumder
- Immunobiology Laboratory, Department of Zoology, University of Delhi, Delhi, 110007, India
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Schlüter D, Barragan A. Advances and Challenges in Understanding Cerebral Toxoplasmosis. Front Immunol 2019; 10:242. [PMID: 30873157 PMCID: PMC6401564 DOI: 10.3389/fimmu.2019.00242] [Citation(s) in RCA: 78] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Accepted: 01/28/2019] [Indexed: 11/22/2022] Open
Abstract
Toxoplasma gondii is a widespread parasitic pathogen that infects over one third of the global human population. The parasite invades and chronically persists in the central nervous system (CNS) of the infected host. Parasite spread and persistence is intimately linked to an ensuing immune response, which does not only limit parasite-induced damage but also may facilitate dissemination and induce parasite-associated immunopathology. Here, we discuss various aspects of toxoplasmosis where knowledge is scarce or controversial and, the recent advances in the understanding of the delicate interplay of T. gondii with the immune system in experimental and clinical settings. This includes mechanisms for parasite passage from the circulation into the brain parenchyma across the blood-brain barrier during primary acute infection. Later, as chronic latent infection sets in with control of the parasite in the brain parenchyma, the roles of the inflammatory response and of immune cell responses in this phase of the disease are discussed. Additionally, the function of brain resident cell populations is delineated, i.e., how neurons, astrocytes and microglia serve both as target cells for the parasite but also actively contribute to the immune response. As the infection can reactivate in the CNS of immune-compromised individuals, we bring up the immunopathogenesis of reactivated toxoplasmosis, including the special case of congenital CNS manifestations. The relevance, advantages and limitations of rodent infection models for the understanding of human cerebral toxoplasmosis are discussed. Finally, this review pinpoints questions that may represent challenges to experimental and clinical science with respect to improved diagnostics, pharmacological treatments and immunotherapies.
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Affiliation(s)
- Dirk Schlüter
- Hannover Medical School, Institute of Medical Microbiology and Hospital Epidemiology, Hannover, Germany
| | - Antonio Barragan
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
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Hatter JA, Kouche YM, Melchor SJ, Ng K, Bouley DM, Boothroyd JC, Ewald SE. Toxoplasma gondii infection triggers chronic cachexia and sustained commensal dysbiosis in mice. PLoS One 2018; 13:e0204895. [PMID: 30379866 PMCID: PMC6209157 DOI: 10.1371/journal.pone.0204895] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Accepted: 09/13/2018] [Indexed: 01/14/2023] Open
Abstract
Toxoplasma gondii is a protozoan parasite with a predation-mediated transmission cycle between rodents and felines. Intermediate hosts acquire Toxoplasma by eating parasite cysts which invade the small intestine, disseminate systemically and finally establish host life-long chronic infection in brain and muscles. Here we show that Toxoplasma infection can trigger a severe form of sustained cachexia: a disease of progressive lean weight loss that is a causal predictor of mortality in cancer, chronic disease and many infections. Toxoplasma cachexia is characterized by acute anorexia, systemic inflammation and loss of 20% body mass. Although mice recover from symptoms of peak sickness, they fail to regain muscle mass or visceral adipose depots. We asked whether the damage to the intestinal microenvironment observed at acute time points was sustained in chronic infection and could thereby play a role in sustaining cachexia. We found that parasites replicate in the same region of the distal jejunum/proximal ileum throughout acute infection, inducing the development of secondary lymphoid structures and severe, regional inflammation. Small intestine pathology was resolved by 5 weeks post-infection. However, changes in the commensal populations, notably an outgrowth of Clostridia spp., were sustained in chronic infection. Importantly, uninfected animals co-housed with infected mice display similar changes in commensal microflora but never display symptoms of cachexia, indicating that altered commensals are not sufficient to explain the cachexia phenotype alone. These studies indicate that Toxoplasma infection is a novel and robust model to study the immune-metabolic interactions that contribute to chronic cachexia development, pathology and potential reversal.
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Affiliation(s)
- Jessica A. Hatter
- Department of Microbiology, Immunology and Cancer Biology and the Carter Immunology Center, University of Virginia School of Medicine, Charlottesville, VA, United States of America
| | - Yue Moi Kouche
- Department of Comparative Medicine, Stanford University, Stanford CA, United States of America
| | - Stephanie J. Melchor
- Department of Microbiology, Immunology and Cancer Biology and the Carter Immunology Center, University of Virginia School of Medicine, Charlottesville, VA, United States of America
| | - Katherine Ng
- Department of Microbiology and Immunology, Stanford University, Stanford CA, United States of America
| | - Donna M. Bouley
- Department of Comparative Medicine, Stanford University, Stanford CA, United States of America
| | - John C. Boothroyd
- Department of Microbiology and Immunology, Stanford University, Stanford CA, United States of America
| | - Sarah E. Ewald
- Department of Microbiology, Immunology and Cancer Biology and the Carter Immunology Center, University of Virginia School of Medicine, Charlottesville, VA, United States of America
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Couturier-Maillard A, Froux N, Piotet-Morin J, Michaudel C, Brault L, Le Bérichel J, Sénéchal A, Robinet P, Chenuet P, Jejou S, Dumoutier L, Renauld JC, Iovanna J, Huber S, Chamaillard M, Quesniaux V, Sokol H, Chamaillard M, Ryffel B. Interleukin-22-deficiency and microbiota contribute to the exacerbation of Toxoplasma gondii-induced intestinal inflammation. Mucosal Immunol 2018; 11:1181-1190. [PMID: 29728643 DOI: 10.1038/s41385-018-0005-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2017] [Revised: 01/04/2018] [Accepted: 01/09/2018] [Indexed: 02/04/2023]
Abstract
Upon oral infection with Toxoplasma gondii cysts (76 K strain) tachyzoites are released into the intestinal lumen and cross the epithelial barrier causing damage and acute intestinal inflammation in C57BL/6 (B6) mice. Here we investigated the role of microbiota and IL-22 in T.gondii-induced small intestinal inflammation. Oral T.gondii infection in B6 mice causes inflammation with IFNγ and IL-22 production. In IL-22-deficient mice, T.gondii infection augments the Th1 driven inflammation. Deficiency in either IL-22bp, the soluble IL-22 receptor or Reg3γ, an IL-22-dependent antimicrobial lectin/peptide, did not reduce inflammation. Under germ-free conditions, T.gondii-induced inflammation was reduced in correlation with parasite load. But intestinal inflammation is still present in germ-free mice, at low level, in the lamina propria, independently of IL-22 expression. Exacerbated intestinal inflammation driven by absence of IL-22 appears to be independent of IL-22 deficiency associated-dysbiosis as similar inflammation was observed after fecal transplantation of IL-22-/- or WT microbiota to germ-free-WT mice. Our results suggest cooperation between parasite and intestinal microbiota in small intestine inflammation development and endogenous IL-22 seems to exert a protective role independently of its effect on the microbiota. In conclusion, IL-22 participates in T.gondii induced acute small intestinal inflammation independently of microbiota and Reg3γ.
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Affiliation(s)
- A Couturier-Maillard
- Laboratory of Experimental and Molecular Immunology and Neurogenetics (INEM), CNRS and University of Orleans (UMR7355), Orléans, France
| | - N Froux
- CNRS UPS44 -TAAM, Orléans, France
| | - J Piotet-Morin
- Laboratory of Experimental and Molecular Immunology and Neurogenetics (INEM), CNRS and University of Orleans (UMR7355), Orléans, France
| | - C Michaudel
- Laboratory of Experimental and Molecular Immunology and Neurogenetics (INEM), CNRS and University of Orleans (UMR7355), Orléans, France
| | - L Brault
- Laboratory of Experimental and Molecular Immunology and Neurogenetics (INEM), CNRS and University of Orleans (UMR7355), Orléans, France
| | - J Le Bérichel
- Laboratory of Experimental and Molecular Immunology and Neurogenetics (INEM), CNRS and University of Orleans (UMR7355), Orléans, France
| | | | - P Robinet
- Laboratory of Experimental and Molecular Immunology and Neurogenetics (INEM), CNRS and University of Orleans (UMR7355), Orléans, France
| | - P Chenuet
- Laboratory of Experimental and Molecular Immunology and Neurogenetics (INEM), CNRS and University of Orleans (UMR7355), Orléans, France
| | - S Jejou
- Sorbonne Universités, UPMC Univ. Paris 06, École Normale Supérieure, PSL Research University, CNRS, INSERM, APHP, Laboratoire des Biomolécules (LBM), 27 rue de Chaligny, 75005, Paris, France
| | - L Dumoutier
- Ludwig Institute for Cancer Research, Université Catholique de Louvain, Brussels, Belgium
| | - J C Renauld
- Ludwig Institute for Cancer Research, Université Catholique de Louvain, Brussels, Belgium
| | - J Iovanna
- INSERM U1068, Centre de Recherche en Cancérologie de Marseille (CRCM), Aix-Marseille Université and Institut Paoli-Calmette, Parc Scientifique et Technologique de Luminy, CNRS UMR 7258, Marseille, France
| | - S Huber
- Medizinische Klinik und Poliklinik, Universitätsklinikum Hamburg-Eppendorf, Hamburg, 20246, Germany
| | | | - Vfj Quesniaux
- Laboratory of Experimental and Molecular Immunology and Neurogenetics (INEM), CNRS and University of Orleans (UMR7355), Orléans, France
| | - H Sokol
- Sorbonne Universités, UPMC Univ. Paris 06, École Normale Supérieure, PSL Research University, CNRS, INSERM, APHP, Laboratoire des Biomolécules (LBM), 27 rue de Chaligny, 75005, Paris, France
- Micalis Institute, Institut National de la Recherche Agronomique (INRA), AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, 78352, France
- Department of Gastroenterology, Saint Antoine Hospital, Assistance Publique-Hopitaux de Paris, UPMC, Paris, France
| | - M Chamaillard
- Department of Gastroenterology, Saint Antoine Hospital, Assistance Publique-Hopitaux de Paris, UPMC, Paris, France
| | - B Ryffel
- Laboratory of Experimental and Molecular Immunology and Neurogenetics (INEM), CNRS and University of Orleans (UMR7355), Orléans, France.
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Watanabe PDS, Trevizan AR, Silva-Filho SE, Góis MB, Garcia JL, Cuman RKN, Breithaupt-Faloppa AC, Sant`Ana DDMG, Nogueira de Melo GDA. Immunocompetent host develops mild intestinal inflammation in acute infection with Toxoplasma gondii. PLoS One 2018; 13:e0190155. [PMID: 29324806 PMCID: PMC5764246 DOI: 10.1371/journal.pone.0190155] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Accepted: 12/08/2017] [Indexed: 12/22/2022] Open
Abstract
Toxoplasma gondii (T. gondii) is the causative agent of toxoplasmosis, common zoonosis among vertebrates and high incidence worldwide. During the infection, the parasite needs to transpose the intestinal barrier to spread throughout the body, which may be a trigger for an inflammatory reaction. This work evaluated the inflammatory alterations of early T. gondii infection in peripheral blood cells, in the mesenteric microcirculation, and small intestinal tissue by measurement of MPO (myeloperoxidase) activity and NO (nitric oxide) level in rats. Animals were randomly assigned into control group (CG) that received saline orally and groups infected with 5,000 oocysts for 6 (G6), 12 (G12), 24 (G24), 48 (G48) and 72 hours (G72). Blood samples were collected for total and differential leukocyte count. Intravital microscopy was performed in the mesentery to evaluate rolling and adhesion of leukocytes. After euthanasia, 0.5cm of the duodenum, jejunum and ileum were collected for the determination of MPO activity, NO level and PCR to identify the parasite DNA and also the mesentery were collected to perform immunohistochemistry on frozen sections to quantify adhesion molecules ICAM-1, PECAM-1 and P-Selectin. The parasite DNA was identified in all infected groups and there was an increase in leukocytes in the peripheral blood and in expression of ICAM-1 and PECAM-1 in G6 and G12, however, the expression of P-selectin was reduced in G12. Leukocytes are in rolling process during the first 12 hours and they are adhered at 24 hours post-infection. The activity of MPO increased in the duodenum at 12 hours, and NO increased in the jejunum in G72 and ileum in G24, G48 and G72. Our study demonstrated that T. gondii initiates the infection precociously (at 6 hours) leading to a systemic activation of innate immune response resulting in mild inflammation in a less susceptible experimental model.
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Affiliation(s)
- Paulo da Silva Watanabe
- Biosciences and Physiopathology Program, Universidade Estadual de Maringá, Maringá, Paraná, Brazil
| | - Aline Rosa Trevizan
- Biosciences and Physiopathology Program, Universidade Estadual de Maringá, Maringá, Paraná, Brazil
| | | | - Marcelo Biondaro Góis
- Biosciences and Physiopathology Program, Universidade Estadual de Maringá, Maringá, Paraná, Brazil
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Understanding host-parasite relationship: the immune central nervous system microenvironment and its effect on brain infections. Parasitology 2017; 145:988-999. [PMID: 29231805 DOI: 10.1017/s0031182017002189] [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] [Indexed: 12/11/2022]
Abstract
The central nervous system (CNS) has been recognized as an immunologically specialized microenvironment, where immune surveillance takes a distinctive character, and where delicate neuronal networks are sustained by anti-inflammatory factors that maintain local homeostasis. However, when a foreign agent such as a parasite establishes in the CNS, a set of immune defences is mounted and several immune molecules are released to promote an array of responses, which ultimately would control the infection and associated damage. Instead, a host-parasite relationship is established, in the context of which a close biochemical coevolution and communication at all organization levels between two complex organisms have developed. The ability of the parasite to establish in its host is associated with several evasion mechanisms to the immune response and its capacity for exploiting host-derived molecules. In this context, the CNS is deeply involved in modulating immune functions, either protective or pathogenic, and possibly in parasitic activity as well, via interactions with evolutionarily conserved molecules such as growth factors, neuropeptides and hormones. This review presents available evidence on some examples of CNS parasitic infections inducing different morbi-mortality grades in low- or middle-income countries, to illustrate how the CNS microenvironment affect pathogen establishment, growth, survival and reproduction in immunocompetent hosts. A better understanding of the influence of the CNS microenvironment on neuroinfections may provide relevant insights into the mechanisms underlying these pathologies.
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Kinetics of parasite distribution after reinfection with genetically distinct strains of Toxoplasma gondii. Exp Parasitol 2017; 184:22-30. [PMID: 29146488 DOI: 10.1016/j.exppara.2017.11.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2017] [Revised: 10/09/2017] [Accepted: 11/12/2017] [Indexed: 02/04/2023]
Abstract
Recent data shows that prior infection by Toxoplasma gondii does not protect the host from subsequent reinfection even after the development of immunological memory. Although animal models for T. gondii reinfection were proposed after cases of natural human reinfection were described, little is known about the events that occur immediately after challenge. To further understand these events, BALB/c mice were chronically infected with D8 non-virulent strain (genotype ToxoDB#8 BrIII) and challenged with two different virulent strains: EGS (genotype ToxoDB #229) or CH3 strain (genotype ToxoDB #19). Primary infection protected animals from lethal challenge and morbidity was reduced. Reinfection was confirmed by PCR-RFLP, showing differences in the way the parasites spread in challenged animals. Parasites reached the lungs during early infection and a parasitism delay in the intestine was observed in D8+CH3 group. Parasites from challenge strains were not detected in the brain of D8+CH3 and in the intestine and brain of D8+EGS group. Previous infection with D8 strain of T. gondii protected against lethal challenges, but it did not prevent parasite spread to some organs.
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Abstract
Toxoplasma gondii is one of the world’s most successful parasites, in part because of its ability to infect and persist in most warm-blooded animals. A unique characteristic of T. gondii is its ability to persist in the central nervous system (CNS) of a variety of hosts, including humans and rodents. How, what, and why T. gondii encysts in the CNS has been the topic of study for decades. In this review, we will discuss recent work on how T. gondii is able to traverse the unique barrier surrounding the CNS, what cells of the CNS play host to T. gondii, and finally, how T. gondii infection may influence global and cellular physiology of the CNS.
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Duodenal toxoplasmosis in a bone marrow transplant patient: A rare case report. HUMAN PATHOLOGY: CASE REPORTS 2017. [DOI: 10.1016/j.ehpc.2016.03.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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Jones EJ, Korcsmaros T, Carding SR. Mechanisms and pathways of Toxoplasma gondii transepithelial migration. Tissue Barriers 2016; 5:e1273865. [PMID: 28452683 PMCID: PMC5362999 DOI: 10.1080/21688370.2016.1273865] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Toxoplasma gondii is a ubiquitous parasite and a prevalent food-borne parasitic pathogen. Infection of the host occurs principally through oral consumption of contaminated food and water with the gastrointestinal tract being the primary route for entry into the host. To promote infection, T. gondii has evolved highly specialized strategies for rapid traversal of the single cell thick intestinal epithelial barrier. Parasite transmigration via the paracellular pathway between adjacent cells enables parasite dissemination to secondary sites of infection where chronic infection of muscle and brain tissue is established. It has recently been proposed that parasite interactions with the integral tight junction (TJ) protein occludin influences parasite transmigration of the intestinal epithelium. We review here the emerging mechanisms of T. gondii transmigration of the small intestinal epithelium alongside the developing role played in modulating the wider TJ-associated proteome to rewire host cell regulatory systems for the benefit of the parasite.
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Affiliation(s)
- Emily J Jones
- a Gut Health and Food Safety Institute Strategic Programme , Institute of Food Research, Norwich Research Park , Norwich , UK.,b Earlham Institute, Norwich Research Park , Norwich , UK
| | - Tamas Korcsmaros
- a Gut Health and Food Safety Institute Strategic Programme , Institute of Food Research, Norwich Research Park , Norwich , UK.,b Earlham Institute, Norwich Research Park , Norwich , UK
| | - Simon R Carding
- a Gut Health and Food Safety Institute Strategic Programme , Institute of Food Research, Norwich Research Park , Norwich , UK.,c Norwich Medical School, University of East Anglia, Norwich Research Park , Norwich , UK
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44
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Toxoplasma gondii: One Organism, Multiple Models. Trends Parasitol 2016; 33:113-127. [PMID: 27988095 DOI: 10.1016/j.pt.2016.11.007] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Revised: 11/15/2016] [Accepted: 11/18/2016] [Indexed: 12/13/2022]
Abstract
Toxoplasma gondii is an intensely studied protozoan parasite. It is also used as a model organism to research additional clinically relevant human and veterinary parasites due to ease of in vitro culture and genetic manipulation. Recently, it has been developed as a model of inflammatory bowel disease, due to their similar pathologies. However, researchers vary widely in how they use T. gondii, which makes study comparisons and interpretation difficult. The aim of this review is to provide researchers with a tool to: (i) determine the appropriateness of the different T. gondii models to their research, (ii) interpret results from the wide range of study conditions, and (iii) consider new advances in technology which could improve or refine their experimental setup.
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Severance EG, Xiao J, Jones-Brando L, Sabunciyan S, Li Y, Pletnikov M, Prandovszky E, Yolken R. Toxoplasma gondii-A Gastrointestinal Pathogen Associated with Human Brain Diseases. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2016; 131:143-163. [PMID: 27793216 DOI: 10.1016/bs.irn.2016.08.008] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Serious psychiatric disorders such as schizophrenia, bipolar disorder, and major depression are important causes of mortality and morbidity worldwide. While these are primarily diseases involving altered brain functioning, numerous studies have documented increased rates of gastrointestinal inflammation and dysfunction in many individuals with these disorders. Toxoplasma gondii is an apicomplexan protozoan intracellular parasite with a widespread distribution in both developed and developing countries. Toxoplasma organisms enter the ecosystem through the shedding of oocysts by Toxoplasma-infected felines. In almost all cases of postnatal human infection, Toxoplasma enters its hosts through the intestinal tract either by the ingestion of oocysts or by the consumption of meat from food animals which themselves were infected by Toxoplasma oocysts. It had previously been thought that most cases of Toxoplasma infection in immune competent children and adults were inapparent and asymptomatic. However, recent studies cast doubt on this concept as exposure to Toxoplasma has been associated with a range of acute and chronic symptoms. Of particular note has been the finding of an increased rate of a range of neurological and psychiatric disorders associated with serological evidence of Toxoplasma exposure. A role of Toxoplasma infection in brain diseases is also supported by the consistent finding of altered cognition and behavior in animal models of infections. Much of the attention relating to the role of Toxoplasma infection in neuropsychiatric disorders has focused on the brain, where Toxoplasma tissue cysts can persist for extended periods of time. However, recent discoveries relating to the role of the gastrointestinal tract in cognition and behavior suggest that Toxoplasma may also increase susceptibility to human brain diseases through immune activation, particularly involving the gastrointestinal mucosa. The study of the pathways relating to the pathobiology and immunology of Toxoplasma infection may provide insights into the pathogenesis of a range of human neuropsychiatric disorders as well as into cognitive functioning in otherwise healthy individuals.
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Affiliation(s)
- E G Severance
- Johns Hopkins School of Medicine, Baltimore, MD, United States
| | - J Xiao
- Johns Hopkins School of Medicine, Baltimore, MD, United States
| | - L Jones-Brando
- Johns Hopkins School of Medicine, Baltimore, MD, United States
| | - S Sabunciyan
- Johns Hopkins School of Medicine, Baltimore, MD, United States
| | - Y Li
- Johns Hopkins School of Medicine, Baltimore, MD, United States
| | - M Pletnikov
- Johns Hopkins School of Medicine, Baltimore, MD, United States
| | - E Prandovszky
- Johns Hopkins School of Medicine, Baltimore, MD, United States
| | - R Yolken
- Johns Hopkins School of Medicine, Baltimore, MD, United States.
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Briceño MP, Nascimento LAC, Nogueira NP, Barenco PVC, Ferro EAV, Rezende-Oliveira K, Goulart LR, Alves PT, Barbosa BDF, Lima WR, Silva NM. Toxoplasma gondii Infection Promotes Epithelial Barrier Dysfunction of Caco-2 Cells. J Histochem Cytochem 2016; 64:459-69. [PMID: 27370796 DOI: 10.1369/0022155416656349] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Accepted: 06/01/2016] [Indexed: 12/12/2022] Open
Abstract
After oral infection, Toxoplasma gondii invades intestinal cells, induces breakdown of intestinal physiology and barrier functions, and causes intestinal pathology in some animal species. Although parasites' invasion into host cells is a known phenomenon, the effects of T. gondii infection in the intestinal barrier are still not well established. To evaluate morphological and physiological modifications on the colorectal adenocarcinoma-derived Caco-2 cell line during T. gondii infection, microvilli, tight junction integrity, and transepithelial electrical resistance (TEER) were investigated under infection. It was observed that the dextran uptake (endocytosis) and distribution were smaller in infected than in noninfected Caco-2 cells. The infection leads to the partial loss of microvilli at the cell surface. Claudin-1, zonula occludens-1 (ZO-1), and occludin expressions were colocalized by immunofluorescence and presented discontinuous net patterns in infected cells. Immunoblotting analysis at 24 hr postinfection revealed decreasing expression of occludin and ZO-1 proteins, whereas claudin-1 presented similar expression level compared with noninfected cells. T. gondii decreased TEER in Caco-2 cells 24 hr after infection. Our results suggest that T. gondii infection may lead to the loss of integrity of intestinal mucosa, resulting in impaired barrier function.
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Affiliation(s)
- Marisol Pallete Briceño
- Laboratory of Immunopathology, Institute of Biomedical Sciences (MPB, LACN, NPN, PVCB, WRL, NMS)
| | | | - Nathalia Pires Nogueira
- Laboratory of Immunopathology, Institute of Biomedical Sciences (MPB, LACN, NPN, PVCB, WRL, NMS)
| | | | - Eloisa Amália Vieira Ferro
- Laboratory of Immunopathology, Institute of Biomedical Sciences (MPB, LACN, NPN, PVCB, WRL, NMS),Laboratory of Immunophysiology of Reproduction, Institute of Biomedical Sciences, Federal University of Uberlândia, Uberlândia, Minas Gerais, Brazil (BFB, EAVF)
| | - Karine Rezende-Oliveira
- Laboratory of Biomedical Sciences, Federal University of Uberlândia, Ituiutaba, Minas Gerais, Brazil (KR-O)
| | - Luiz Ricardo Goulart
- Laboratory of Nanobiotechnology, Institute of Genetics and Biochemistry, Federal University of Uberlândia, Uberlândia, Minas Gerais, Brazil (LRG, PTA)
| | - Patrícia Terra Alves
- Laboratory of Immunopathology, Institute of Biomedical Sciences (MPB, LACN, NPN, PVCB, WRL, NMS),Laboratory of Nanobiotechnology, Institute of Genetics and Biochemistry, Federal University of Uberlândia, Uberlândia, Minas Gerais, Brazil (LRG, PTA)
| | - Bellisa de Freitas Barbosa
- Laboratory of Immunophysiology of Reproduction, Institute of Biomedical Sciences, Federal University of Uberlândia, Uberlândia, Minas Gerais, Brazil (BFB, EAVF)
| | - Wânia Rezende Lima
- Laboratory of Immunopathology, Institute of Biomedical Sciences (MPB, LACN, NPN, PVCB, WRL, NMS),Institute of Exact and Natural Sciences, Federal University of Mato Grosso, Rondonópolis, Mato Grosso, Brazil (WRL)
| | - Neide Maria Silva
- Laboratory of Immunopathology, Institute of Biomedical Sciences (MPB, LACN, NPN, PVCB, WRL, NMS)
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Long-Term Relationships: the Complicated Interplay between the Host and the Developmental Stages of Toxoplasma gondii during Acute and Chronic Infections. Microbiol Mol Biol Rev 2016; 79:387-401. [PMID: 26335719 DOI: 10.1128/mmbr.00027-15] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Toxoplasma gondii represents one of the most common parasitic infections in the world. The asexual cycle can occur within any warm-blooded animal, but the sexual cycle is restricted to the feline intestinal epithelium. T. gondii is acquired through consumption of tissue cysts in undercooked meat as well as food and water contaminated with oocysts. Once ingested, it differentiates into a rapidly replicating asexual form and disseminates throughout the body during acute infection. After stimulation of the host immune response, T. gondii differentiates into a slow-growing, asexual cyst form that is the hallmark of chronic infection. One-third of the human population is chronically infected with T. gondii cysts, which can reactivate and are especially dangerous to individuals with reduced immune surveillance. Serious complications can also occur in healthy individuals if infected with certain T. gondii strains or if infection is acquired congenitally. No drugs are available to clear the cyst form during the chronic stages of infection. This therapeutic gap is due in part to an incomplete understanding of both host and pathogen responses during the progression of T. gondii infection. While many individual aspects of T. gondii infection are well understood, viewing the interconnections between host and parasite during acute and chronic infection may lead to better approaches for future treatment. The aim of this review is to provide an overview of what is known and unknown about the complex relationship between the host and parasite during the progression of T. gondii infection, with the ultimate goal of bridging these events.
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48
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Ueno N, Lodoen MB. From the blood to the brain: avenues of eukaryotic pathogen dissemination to the central nervous system. Curr Opin Microbiol 2015; 26:53-9. [PMID: 26048316 PMCID: PMC10538213 DOI: 10.1016/j.mib.2015.05.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Revised: 05/07/2015] [Accepted: 05/08/2015] [Indexed: 12/25/2022]
Abstract
Infection of the central nervous system (CNS) is a significant cause of morbidity and mortality, and treatments available to combat the highly debilitating symptoms of CNS infection are limited. The mechanisms by which pathogens in the circulation overcome host immunity and breach the blood-brain barrier are active areas of investigation. In this review, we discuss recent work that has significantly advanced our understanding of the avenues of pathogen dissemination to the CNS for four eukaryotic pathogens of global health importance: Toxoplasma gondii, Plasmodium falciparum, Trypanosoma brucei, and Cryptococcus neoformans. These studies highlight the remarkable diversity of pathogen strategies for trafficking to the brain and will ultimately contribute to an improved ability to combat life-threatening CNS disease.
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Affiliation(s)
- Norikiyo Ueno
- Department of Molecular Biology and Biochemistry and the Institute for Immunology, University of California, Irvine, CA, USA
| | - Melissa B Lodoen
- Department of Molecular Biology and Biochemistry and the Institute for Immunology, University of California, Irvine, CA, USA.
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Weight CM, Jones EJ, Horn N, Wellner N, Carding SR. Elucidating pathways of Toxoplasma gondii invasion in the gastrointestinal tract: involvement of the tight junction protein occludin. Microbes Infect 2015; 17:698-709. [PMID: 26183539 DOI: 10.1016/j.micinf.2015.07.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Revised: 06/17/2015] [Accepted: 07/02/2015] [Indexed: 01/28/2023]
Abstract
Toxoplasma gondii is an obligate intracellular parasite infecting one third of the world's population. The small intestine is the parasite's primary route of infection, although the pathway of epithelium transmigration remains unclear. Using an in vitro invasion assay and live imaging we showed that T. gondii (RH) tachyzoites infect and transmigrate between adjacent intestinal epithelial cells in polarized monolayers without altering barrier integrity, despite eliciting the production of specific inflammatory mediators and chemokines. During invasion, T. gondii co-localized with occludin. Reducing the levels of endogenous cellular occludin with specific small interfering RNAs significantly reduced the ability of T. gondii to penetrate between and infect epithelial cells. Furthermore, an in vitro invasion and binding assays using recombinant occludin fragments established the capacity of the parasite to bind occludin and in particular to the extracellular loops of the protein. These findings provide evidence for occludin playing a role in the invasion of T. gondii in small intestinal epithelial cells.
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Affiliation(s)
- Caroline M Weight
- Gut Health and Food Safety Institute Strategic Programme, Norwich Research Park, Norwich, NR4 7UA, UK; Norwich Medical School, University of East Anglia, Norwich Research Park, Norwich, NR4 7UA, UK
| | - Emily J Jones
- Gut Health and Food Safety Institute Strategic Programme, Norwich Research Park, Norwich, NR4 7UA, UK; Norwich Medical School, University of East Anglia, Norwich Research Park, Norwich, NR4 7UA, UK
| | - Nikki Horn
- Gut Health and Food Safety Institute Strategic Programme, Norwich Research Park, Norwich, NR4 7UA, UK
| | - Nikolaus Wellner
- Analytical Sciences Unit, Institute of Food Research, Norwich Research Park, Norwich, NR4 7UA, UK
| | - Simon R Carding
- Gut Health and Food Safety Institute Strategic Programme, Norwich Research Park, Norwich, NR4 7UA, UK; Norwich Medical School, University of East Anglia, Norwich Research Park, Norwich, NR4 7UA, UK.
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Lack of a Functioning P2X7 Receptor Leads to Increased Susceptibility to Toxoplasmic Ileitis. PLoS One 2015; 10:e0129048. [PMID: 26053862 PMCID: PMC4460092 DOI: 10.1371/journal.pone.0129048] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Accepted: 05/04/2015] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Oral infection of C57BL/6J mice with the protozoan parasite Toxoplasma gondii leads to a lethal inflammatory ileitis. PRINCIPAL FINDINGS Mice lacking the purinergic receptor P2X7R are acutely susceptible to toxoplasmic ileitis, losing significantly more weight than C57BL/6J mice and exhibiting much greater intestinal inflammatory pathology in response to infection with only 10 cysts of T. gondii. This susceptibility is not dependent on the ability of P2X7R-deficient mice to control the parasite, which they accomplish just as efficiently as C57BL/6J mice. Rather, susceptibility is associated with elevated ileal concentrations of pro-inflammatory cytokines, reactive nitrogen intermediates and altered regulation of elements of NFκB activation in P2X7R-deficient mice. CONCLUSIONS Our data support the thesis that P2X7R, a well-documented activator of pro-inflammatory cytokine production, also plays an important role in the regulation of intestinal inflammation.
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