1
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Abhyankar MM, Xu F, Chavez D, Goodroe A, Mendoza E, Chen C, Singh DK, Varnador F, Sivananthan SJ, Kinsey R, Lykins WR, Murphy BM, Martin AR, Tomai MA, Ghosal S, Casper C, Pedersen K, Petri WA, Fox CB. Immunogenicity and safety of an Entamoeba histolytica adjuvanted protein vaccine candidate (LecA+GLA-3M-052 liposomes) in rhesus macaques. Hum Vaccin Immunother 2024; 20:2374147. [PMID: 39090779 PMCID: PMC11296537 DOI: 10.1080/21645515.2024.2374147] [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: 04/23/2024] [Revised: 06/20/2024] [Accepted: 06/26/2024] [Indexed: 08/04/2024] Open
Abstract
Entamoeba histolytica, the causative agent of amebiasis, is one of the top three parasitic causes of mortality worldwide. However, no vaccine exists against amebiasis. Using a lead candidate vaccine containing the LecA fragment of Gal-lectin and GLA-3M-052 liposome adjuvant, we immunized rhesus macaques via intranasal or intramuscular routes. The vaccine elicited high-avidity functional humoral responses as seen by the inhibition of amebic attachment to mammalian target cells by plasma and stool antibodies. Importantly, antigen-specific IFN-γ-secreting peripheral blood mononuclear cells (PBMCs) and IgG/IgA memory B cells (BMEM) were detected in immunized animals. Furthermore, antigen-specific antibody and cellular responses were maintained for at least 8 months after the final immunization as observed by robust LecA-specific BMEM as well as IFN-γ+ PBMC responses. Overall, both intranasal and intramuscular immunizations elicited a durable and functional response in systemic and mucosal compartments, which supports advancing the LecA+GLA-3M-052 liposome vaccine candidate to clinical testing.
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MESH Headings
- Animals
- Macaca mulatta
- Entamoeba histolytica/immunology
- Liposomes/immunology
- Liposomes/administration & dosage
- Protozoan Vaccines/immunology
- Protozoan Vaccines/administration & dosage
- Antibodies, Protozoan/blood
- Antibodies, Protozoan/immunology
- Leukocytes, Mononuclear/immunology
- Entamoebiasis/prevention & control
- Entamoebiasis/immunology
- Administration, Intranasal
- Interferon-gamma/immunology
- Interferon-gamma/metabolism
- Injections, Intramuscular
- Immunogenicity, Vaccine
- Adjuvants, Vaccine/administration & dosage
- Adjuvants, Immunologic/administration & dosage
- B-Lymphocytes/immunology
- Immunoglobulin G/blood
- Immunoglobulin G/immunology
- Immunoglobulin A/immunology
- Immunoglobulin A/blood
- Antigens, Protozoan/immunology
- Immunity, Humoral
- Immunologic Memory
- Protozoan Proteins/immunology
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Affiliation(s)
- Mayuresh M. Abhyankar
- Division of Infectious Diseases and International Health, School of Medicine, University of Virginia Health System, Charlottesville, VA, USA
| | - Feifan Xu
- Division of Infectious Diseases and International Health, School of Medicine, University of Virginia Health System, Charlottesville, VA, USA
| | - Deborah Chavez
- Southwest National Primate Research Center, Texas Biomedical Research Institute, San Antonio, TX, USA
| | - Anna Goodroe
- Southwest National Primate Research Center, Texas Biomedical Research Institute, San Antonio, TX, USA
| | - Elda Mendoza
- Southwest National Primate Research Center, Texas Biomedical Research Institute, San Antonio, TX, USA
| | - Christopher Chen
- Southwest National Primate Research Center, Texas Biomedical Research Institute, San Antonio, TX, USA
| | - Dhiraj K. Singh
- Southwest National Primate Research Center, Texas Biomedical Research Institute, San Antonio, TX, USA
| | - Fernando Varnador
- Southwest National Primate Research Center, Texas Biomedical Research Institute, San Antonio, TX, USA
| | | | - Robert Kinsey
- Formulations, Access to Advanced Health Institute (AAHI), Seattle, WA, USA
| | - William R. Lykins
- Formulations, Access to Advanced Health Institute (AAHI), Seattle, WA, USA
| | - Brynn M. Murphy
- Department of Mechanical Engineering, University of Alberta, Edmonton, AB, Canada
| | - Andrew R. Martin
- Department of Mechanical Engineering, University of Alberta, Edmonton, AB, Canada
| | - Mark A. Tomai
- Contract Employee for 3M Healthcare, Saint Paul, MN, USA
| | - Soutik Ghosal
- Division of Biostatistics, Department of Public Health Sciences, School of Medicine, University of Virginia, Charlottesville, VA, USA
| | - Corey Casper
- Formulations, Access to Advanced Health Institute (AAHI), Seattle, WA, USA
- Department of Medicine, University of Washington, Seattle, WA, USA
- Department of Global Health, University of Washington, Seattle, WA, USA
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Center, Seattle, WA, USA
| | - Karl Pedersen
- Process Development, TechLab Inc, Blacksburg, VA, USA
| | - William A. Petri
- Division of Infectious Diseases and International Health, School of Medicine, University of Virginia Health System, Charlottesville, VA, USA
| | - Christopher B. Fox
- Formulations, Access to Advanced Health Institute (AAHI), Seattle, WA, USA
- Department of Global Health, University of Washington, Seattle, WA, USA
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2
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Guillén N. Pathogenicity and virulence of Entamoeba histolytica, the agent of amoebiasis. Virulence 2023; 14:2158656. [PMID: 36519347 DOI: 10.1080/21505594.2022.2158656] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Accepted: 12/11/2022] [Indexed: 12/23/2022] Open
Abstract
The amoeba parasite Entamoeba histolytica is the causative agent of human amebiasis, an enteropathic disease affecting millions of people worldwide. This ancient protozoan is an elementary example of how parasites evolve with humans, e.g. taking advantage of multiple mechanisms to evade immune responses, interacting with microbiota for nutritional and protective needs, utilizing host resources for growth, division, and encystation. These skills of E. histolytica perpetuate the species and incidence of infection. However, in 10% of infected cases, the parasite turns into a pathogen; the host-parasite equilibrium is then disorganized, and the simple lifecycle based on two cell forms, trophozoites and cysts, becomes unbalanced. Trophozoites acquire a virulent phenotype which, when non-controlled, leads to intestinal invasion with the onset of amoebiasis symptoms. Virulent E. histolytica must cross mucus, epithelium, connective tissue and possibly blood. This highly mobile parasite faces various stresses and a powerful host immune response, with oxidative stress being a challenge for its survival. New emerging research avenues and omics technologies target gene regulation to determine human or parasitic factors activated upon infection, their role in virulence activation, and in pathogenesis; this research bears in mind that E. histolytica is a resident of the complex intestinal ecosystem. The goal is to eradicate amoebiasis from the planet, but the parasitic life of E. histolytica is ancient and complex and will likely continue to evolve with humans. Advances in these topics are summarized here.
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Affiliation(s)
- Nancy Guillén
- Cell Biology and Infection Department, Institut Pasteur and Centre National de la Recherche Scientifique CNRS-ERM9195, Paris, France
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3
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Zanditenas E, Trebicz-Geffen M, Kolli D, Domínguez-García L, Farhi E, Linde L, Romero D, Chapman M, Kolodkin-Gal I, Ankri S. Digestive exophagy of biofilms by intestinal amoeba and its impact on stress tolerance and cytotoxicity. NPJ Biofilms Microbiomes 2023; 9:77. [PMID: 37813896 PMCID: PMC10562373 DOI: 10.1038/s41522-023-00444-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Accepted: 09/26/2023] [Indexed: 10/11/2023] Open
Abstract
The human protozoan parasite Entamoeba histolytica is responsible for amebiasis, a disease endemic to developing countries. E. histolytica trophozoites colonize the large intestine, primarily feeding on bacteria. However, in the gastrointestinal tract, bacterial cells form aggregates or structured communities called biofilms too large for phagocytosis. Remarkably, trophozoites are still able to invade and degrade established biofilms, utilizing a mechanism that mimics digestive exophagy. Digestive exophagy refers to the secretion of digestive enzymes that promote the digestion of objects too large for direct phagocytosis by phagocytes. E. histolytica cysteine proteinases (CPs) play a crucial role in the degradation process of Bacillus subtilis biofilm. These proteinases target TasA, a major component of the B. subtilis biofilm matrix, also contributing to the adhesion of the parasite to the biofilm. In addition, they are also involved in the degradation of biofilms formed by Gram-negative and Gram-positive enteric pathogens. Furthermore, biofilms also play an important role in protecting trophozoites against oxidative stress. This specific mechanism suggests that the amoeba has adapted to prey on biofilms, potentially serving as an untapped reservoir for novel therapeutic approaches to treat biofilms. Consistently, products derived from the amoeba have been shown to restore antibiotic sensitivity to biofilm cells. In addition, our findings reveal that probiotic biofilms can act as a protective shield for mammalian cells, hindering the progression of the parasite towards them.
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Affiliation(s)
- Eva Zanditenas
- Department of Molecular Microbiology, Ruth and Bruce Rappaport Faculty of Medicine, Technion, Haifa, Israel
| | - Meirav Trebicz-Geffen
- Department of Molecular Microbiology, Ruth and Bruce Rappaport Faculty of Medicine, Technion, Haifa, Israel
| | - Divya Kolli
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, USA
| | - Laura Domínguez-García
- Departamento de Microbiología, Instituto de Hortofruticultura Subtropical y Mediterránea 'La Mayora', Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Universidad de Málaga, Málaga, Spain
| | - Einan Farhi
- Technion Genomics Center, Technion - Israel Institute of Technology, Haifa, Israel
| | - Liat Linde
- Technion Genomics Center, Technion - Israel Institute of Technology, Haifa, Israel
| | - Diego Romero
- Departamento de Microbiología, Instituto de Hortofruticultura Subtropical y Mediterránea 'La Mayora', Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Universidad de Málaga, Málaga, Spain
| | - Matthew Chapman
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, USA
| | - Ilana Kolodkin-Gal
- Department of Plant Pathology and Microbiology, the Robert H. Smith Faculty of Agriculture, Food & Environment, The Hebrew University of Jerusalem, Rehovot, Israel.
- Scojen Institute for Synthetic Biology, Reichman University, Herzliya, Israel.
| | - Serge Ankri
- Department of Molecular Microbiology, Ruth and Bruce Rappaport Faculty of Medicine, Technion, Haifa, Israel.
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Roy M, Chakraborty S, Kumar Srivastava S, Kaushik S, Jyoti A, Kumar Srivastava V. Entamoeba histolytica induced NETosis and the dual role of NETs in amoebiasis. Int Immunopharmacol 2023; 118:110100. [PMID: 37011501 DOI: 10.1016/j.intimp.2023.110100] [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: 11/28/2022] [Revised: 03/23/2023] [Accepted: 03/23/2023] [Indexed: 04/04/2023]
Abstract
Entamoeba histolytica (Eh), a microaerophilic parasite, causes deadly enteric infections that result in Amoebiasis. Every year, the count of invasive infections reaches 50 million approximately and 40,000 to 1,00,000 deaths occurring due to amoebiasis are reported globally. Profound inflammation is the hallmark of severe amoebiasis which is facilitated by immune first defenders, neutrophils. Due to size incompatibility, neutrophils are unable to phagocytose Eh and thus, came up with the miraculous antiparasitic mechanism of neutrophil extracellular traps (NETs). This review provides an in-depth analysis of NETosis induced by Eh including the antigens involved in the recognition of Eh and the biochemistry of NET formation. Additionally, it underscores its novelty by describing the dual role of NETs in amoebiasis where it acts as a double-edged sword in terms of both clearing and exacerbating amoebiasis. It also provides a comprehensive account of the virulence factors discovered to date that are implicated directly and indirectly in the pathophysiology of Eh infections through the lens of NETs and can be interesting drug targets.
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Affiliation(s)
- Mrinalini Roy
- Amity Institute of Biotechnology, Amity University Rajasthan, Kant Kalwar, NH-11C, Jaipur-Delhi Highway, Jaipur, India
| | - Shreya Chakraborty
- Amity Institute of Biotechnology, Amity University Rajasthan, Kant Kalwar, NH-11C, Jaipur-Delhi Highway, Jaipur, India
| | | | - Sanket Kaushik
- Amity Institute of Biotechnology, Amity University Rajasthan, Kant Kalwar, NH-11C, Jaipur-Delhi Highway, Jaipur, India
| | - Anupam Jyoti
- Department of Biotechnology, University Institute of Biotechnology, Chandigarh University, NH-95, Chandigarh-Ludhiana Highway, Mohali, India
| | - Vijay Kumar Srivastava
- Amity Institute of Biotechnology, Amity University Rajasthan, Kant Kalwar, NH-11C, Jaipur-Delhi Highway, Jaipur, India.
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5
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Yanagawa Y, Singh U. Diversity and Plasticity of Virulent Characteristics of Entamoeba histolytica. Trop Med Infect Dis 2023; 8:tropicalmed8050255. [PMID: 37235303 DOI: 10.3390/tropicalmed8050255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 04/27/2023] [Accepted: 04/27/2023] [Indexed: 05/28/2023] Open
Abstract
The complexity of clinical syndromes of amebiasis, caused by the parasite Entamoeba histolytica, stems from the intricate interplay between the host immune system, the virulence of the invading parasite, and the surrounding environment. Although there is still a relative paucity of information about the precise relationship between virulence factors and the pathogenesis of Entamoeba histolytica, by accumulating data from clinical and basic research, researchers have identified essential pathogenic factors that play a critical role in the pathogenesis of amebiasis, providing important insights into disease development through animal models. Moreover, the parasite's genetic variability has been associated with differences in virulence and disease outcomes, making it important to fully understand the epidemiology and pathogenesis of amebiasis. Deciphering the true mechanism of disease progression in humans caused by this parasite is made more difficult through its ability to demonstrate both genomic and pathological plasticity. The objective of this article is to underscore the heterogeneous nature of disease states and the malleable virulence characteristics in experimental models, while also identifying persistent scientific issues that need to be addressed.
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Affiliation(s)
- Yasuaki Yanagawa
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Upinder Singh
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA
- Division of Infectious Diseases, Department of Internal Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
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6
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Wang S, Moreau F, Chadee K. Gasdermins in Innate Host Defense Against Entamoeba histolytica and Other Protozoan Parasites. Front Immunol 2022; 13:900553. [PMID: 35795683 PMCID: PMC9251357 DOI: 10.3389/fimmu.2022.900553] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2022] [Accepted: 05/23/2022] [Indexed: 11/16/2022] Open
Abstract
Gasdermins (GSDMs) are a group of proteins that are cleaved by inflammatory caspases to induce pore formation in the plasma membrane to cause membrane permeabilization and lytic cell death or pyroptosis. All GSDMs share a conserved structure, containing a cytotoxic N-terminal (NT) pore-forming domain and a C-terminal (CT) repressor domain. Entamoeba histolytica (Eh) in contact with macrophages, triggers outside-in signaling to activate inflammatory caspase-4/1 via the noncanonical and canonical pathway to promote cleavage of gasdermin D (GSDMD). Cleavage of GSDMD removes the auto-inhibition that masks the active pore-forming NT domain in the full-length protein by interactions with GSDM-CT. The cleaved NT-GSDMD monomers then oligomerize to form pores in the plasma membrane to facilitate the release of IL-1β and IL-18 with a measured amount of pyroptosis. Pyroptosis is an effective way to counteract intracellular parasites, which exploit replicative niche to avoid killing. To date, most GSDMs have been verified to perform pore-forming activity and GSDMD-induced pyroptosis is rapidly emerging as a mechanism of anti-microbial host defence. Here, we review our comprehensive and current knowledge on the expression, activation, biological functions, and regulation of GSDMD cleavage with emphases on physiological scenario and related dysfunctions of each GSDM member as executioner of cell death, cytokine secretion and inflammation against Eh and other protozoan parasitic infections.
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Affiliation(s)
| | | | - Kris Chadee
- Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, AB, Canada
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7
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Ricin B lectin-like proteins of the microsporidian Encephalitozoon cuniculi and Anncaliia algerae are involved in host-cell invasion. Parasitol Int 2021; 87:102518. [PMID: 34808329 DOI: 10.1016/j.parint.2021.102518] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 10/18/2021] [Accepted: 11/14/2021] [Indexed: 01/03/2023]
Abstract
Microsporidia are obligate intracellular pathogens capable of infecting a wide variety of hosts ranging from invertebrates to vertebrates. The infection process requires a step of prior adherence of Microsporidia to the surface of host cells. A few studies demonstrated the involvement of proteins containing a ricin-B lectin (RBL) domain in parasite infection. In this study Anncalia algerae and Encephalitozoon cuniculi genomes were screened by bioinformatic analysis to identify proteins with an extracellular prediction and possessing RBL-type carbohydrate-binding domains, being both potentially relevant factors contributing to host cell adherence. Three proteins named AaRBLL-1 and AaRBLL-2 from A. algerae and EcRBLL-1 from E. cuniculi, were selected and comparative analysis of sequences suggested their belonging to a multigenic family, with a conserved structural RBL domain despite a significant amino acid sequence divergence. The production of recombinant proteins and antibodies against the three proteins allowed their subcellular localization on the spore wall and/or the polar tube. Adherence inhibition assays based on pre-treatments with recombinant proteins or antibodies highlighted the significant decrease of the proliferation of both E. cuniculi and A. algerae, strongly suggesting that these proteins are involved in the infection process.
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8
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Nakada-Tsukui K, Nozaki T. Trogocytosis in Unicellular Eukaryotes. Cells 2021; 10:cells10112975. [PMID: 34831198 PMCID: PMC8616307 DOI: 10.3390/cells10112975] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 09/25/2021] [Accepted: 10/17/2021] [Indexed: 12/12/2022] Open
Abstract
Trogocytosis is a mode of internalization of a part of a live cell by nibbling and is mechanistically distinct from phagocytosis, which implies internalization of a whole cell or a particle. Trogocytosis has been demonstrated in a broad range of cell types in multicellular organisms and is also known to be involved in a plethora of functions. In immune cells, trogocytosis is involved in the "cross-dressing" between antigen presenting cells and T cells, and is thus considered to mediate intercellular communication. On the other hand, trogocytosis has also been reported in a variety of unicellular organisms including the protistan (protozoan) parasite Entamoeba histolytica. E. histolytica ingests human T cell line by trogocytosis and acquires complement resistance and cross-dresses major histocompatibility complex (MHC) class I on the cell surface. Furthermore, trogocytosis and trogocytosis-like phenomena (nibbling of a live cell, not previously described as trogocytosis) have also been reported in other parasitic protists such as Trichomonas, Plasmodium, Toxoplasma, and free-living amoebae. Thus, trogocytosis is conserved in diverse eukaryotic supergroups as a means of intercellular communication. It is depicting the universality of trogocytosis among eukaryotes. In this review, we summarize our current understanding of trogocytosis in unicellular organisms, including the history of its discovery, taxonomical distribution, roles, and molecular mechanisms.
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Affiliation(s)
- Kumiko Nakada-Tsukui
- Department of Parasitology, National Institute of Infectious Diseases, Tokyo 162-8640, Japan
- Correspondence: (K.N.-T.); (T.N.); Tel.: +81-3-5285-1111 (K.N.-T.); +81-3-5841-3526 (T.N.)
| | - Tomoyoshi Nozaki
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Tokyo 113-8654, Japan
- Correspondence: (K.N.-T.); (T.N.); Tel.: +81-3-5285-1111 (K.N.-T.); +81-3-5841-3526 (T.N.)
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9
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Chadha A, Chadee K. The NF-κB Pathway: Modulation by Entamoeba histolytica and Other Protozoan Parasites. Front Cell Infect Microbiol 2021; 11:748404. [PMID: 34595137 PMCID: PMC8476871 DOI: 10.3389/fcimb.2021.748404] [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: 07/27/2021] [Accepted: 08/27/2021] [Indexed: 12/15/2022] Open
Abstract
Protozoan parasites have led to worldwide devastation because of their ability to cause infectious diseases. They have evolved as successful pathogens in part because of their remarkable and sophisticated ways to evade innate host defenses. This holds true for both intracellular and extracellular parasites that deploy multiple strategies to circumvent innate host defenses for their survival. The different strategies protozoan parasites use include hijacking the host cellular signaling pathways and transcription factors. In particular, the nuclear factor-κB (NF-κB) pathway seems to be an attractive target for different pathogens owing to their central role in regulating prompt innate immune responses in host defense. NF-κB is a ubiquitous transcription factor that plays an indispensable role not only in regulating immediate immune responses against invading pathogens but is also a critical regulator of cell proliferation and survival. The major immunomodulatory components include parasite surface and secreted proteins/enzymes and stimulation of host cells intracellular pathways and inflammatory caspases that directly or indirectly interfere with the NF-κB pathway to thwart immune responses that are directed for containment and/or elimination of the pathogen. To showcase how protozoan parasites exploits the NF-κB signaling pathway, this review highlights recent advances from Entamoeba histolytica and other protozoan parasites in contact with host cells that induce outside-in and inside-out signaling to modulate NF-κB in disease pathogenesis and survival in the host.
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Affiliation(s)
- Attinder Chadha
- Departments of Microbiology, Immunology, and Infectious Diseases, Cumming School of Medicine, Snyder Institute for Chronic Diseases, University of Calgary, Calgary, AB, Canada
| | - Kris Chadee
- Departments of Microbiology, Immunology, and Infectious Diseases, Cumming School of Medicine, Snyder Institute for Chronic Diseases, University of Calgary, Calgary, AB, Canada
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10
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Chadha A, Moreau F, Wang S, Dufour A, Chadee K. Entamoeba histolytica activation of caspase-1 degrades cullin that attenuates NF-κB dependent signaling from macrophages. PLoS Pathog 2021; 17:e1009936. [PMID: 34499701 PMCID: PMC8454965 DOI: 10.1371/journal.ppat.1009936] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 09/21/2021] [Accepted: 09/01/2021] [Indexed: 12/18/2022] Open
Abstract
While Entamoeba histolytica (Eh)-induced pro-inflammatory responses are critical in disease pathogenesis, the downstream signaling pathways that subsequently dampens inflammation and the immune response remains unclear. Eh in contact with macrophages suppresses NF-κB signaling while favoring NLRP3-dependent pro-inflammatory cytokine production by an unknown mechanism. Cullin-1 and cullin-5 (cullin-1/5) assembled into a multi-subunit RING E3 ubiquitin ligase complex are substrates for neddylation that regulates the ubiquitination pathway important in NF-κB activity and pro-inflammatory cytokine production. In this study, we showed that upon live Eh contact with human macrophages, cullin-1/4A/4B/5 but not cullin-2/3, were degraded within 10 minutes. Similar degradation of cullin-1/5 were observed from colonic epithelial cells and proximal colonic loops tissues of mice inoculated with live Eh. Degradation of cullin-1/5 was dependent on Eh-induced activation of caspase-1 via the NLRP3 inflammasome. Unlike cullin-4B, the degradation of cullin-4A was partially dependent on caspase-1 and was inhibited with a pan caspase inhibitor. Cullin-1/5 degradation was dependent on Eh cysteine proteinases EhCP-A1 and EhCP-A4, but not EhCP-A5, based on pharmacological inhibition of the cysteine proteinases and EhCP-A5 deficient parasites. siRNA silencing of cullin-1/5 decreased the phosphorylation of pIκ-Bα in response to Eh and LPS stimulation and downregulated NF-κB-dependent TNF-α mRNA expression and TNF-α and MCP-1 pro-inflammatory cytokine production. These results unravel a unique outside-in strategy employed by Eh to attenuate NF-κB-dependent pro-inflammatory responses via NLRP3 activation of caspase-1 that degraded cullin-1/5 from macrophages. The protozoan parasite Entamoeba histolytica (Eh) is the etiologic agent for the disease amebiasis. It is a potent pathogen that deploys an arsenal of virulence factors to trigger and subvert host immune defenses. One of the hallmark features of the disease is amebic colitis and in extreme cases, it can lead to abscesses of the liver and brain. For unknown reasons, the parasite breaches colonic mucosal barriers and invade underlying tissues. The host immune system plays a decisive role in determining the outcome of the disease. At the molecular level, the interaction of Eh with macrophage is a turning point in shaping pro-inflammatory responses. Understanding host-pathogen intricacies at the molecular level is key in determining the complexity of the disease. In the context of amebiasis, the underlying molecular events that occur at the Eh-macrophage intercellular junction are partly unravelled. Here we sought to interrogate the mechanisms by which NF-κB signaling is aborted following Eh-macrophage contact and found two regulatory scaffold proteins, cullin-1 and -5 (cullin-1/5) of the multiple E3 ligase complex, are degraded leading to dampening of NF-κB signaling. During Eh-macrophage contact, cullin-1/4A/4B/5 were rapidly degraded whereas cullin-2/3 were not. The degradation of cullin-1/5 was highly dependent on Eh-induced caspase-1 activation via the NLRP3 inflammasome. In contrast, the degradation of cullin-4A but not cullin-4B, was partially dependent on caspase-1 and was inhibited with a cell-permeable pan caspase inhibitor. Intriguingly, we found that Eh virulence factor EhCP-A1 and EhCP-A4, but not EhCP-A5, played an important role in mediating the degradation of these proteins. Silencing cullin-1/5 decreased the phosphorylation of Iκ-Bα in response to Eh and LPS stimulation that markedly downregulated NF-κB-dependent TNF-α mRNA expression and TNF-α and MCP-1 pro-inflammatory cytokine production. This study unravelled a novel role for Eh-induced NLRP3 inflammasome activation of caspase-1 that intersected with the NF-κB pathway leading to the degradation of the novel substrates cullin-1/5 that regulates NF-κB-dependent pro-inflammatory cytokine production.
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Affiliation(s)
- Attinder Chadha
- Departments of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, Alberta, Canada
| | - France Moreau
- Departments of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, Alberta, Canada
| | - Shanshan Wang
- Departments of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, Alberta, Canada
| | - Antoine Dufour
- Physiology and Pharmacology, University of Calgary, Calgary, Alberta, Canada
- Biochemistry and Molecular Biology, Snyder Institute for Chronic Diseases, University of Calgary, Calgary, Alberta, Canada
| | - Kris Chadee
- Departments of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, Alberta, Canada
- * E-mail:
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Begum S, Moreau F, Dufour A, Chadee K. Entamoeba histolytica exploits the autophagy pathway in macrophages to trigger inflammation in disease pathogenesis. Mucosal Immunol 2021; 14:1038-1054. [PMID: 33963264 DOI: 10.1038/s41385-021-00408-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 03/25/2021] [Accepted: 04/16/2021] [Indexed: 02/04/2023]
Abstract
The mechanism whereby Entamoeba histolytica (Eh) binding with macrophages at the intercellular junction triggers aggressive pro-inflammatory responses in disease pathogenesis is not well understood. The host intracellular protein degradation process autophagy and its regulatory proteins are involved in maintenance of cellular homeostasis and excessive inflammatory responses. In this study we unraveled how Eh hijacks the autophagy process in macrophages to dysregulate pro-inflammatory responses. Direct contact of live Eh with macrophages activated caspase-6 that induced rapid proteolytic degradation of the autophagy ATG16L1 protein complex independent of NLRP3 inflammasome and caspase-3/8 activation. Crohn's disease susceptible ATG16L1 T300A variant was highly susceptible to Eh-mediated degradation that augmented pro-inflammatory cytokines in mice. Quantitative proteomics revealed downregulation of autophagy and vesicle-mediated transport and upregulation of cysteine-type endopeptidase pathways in response to Eh. We conclude during Eh-macrophage outside-in signaling, ATG16L1 protein complex plays an overlooked regulatory role in shaping the pro-inflammatory landscape in amebiasis.
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Affiliation(s)
- Sharmin Begum
- Departments of Microbiology, Immunology and Infectious Diseases, Calgary, AB, Canada
| | - France Moreau
- Departments of Microbiology, Immunology and Infectious Diseases, Calgary, AB, Canada
| | - Antoine Dufour
- Physiology and Pharmacology, Snyder Institute for Chronic Diseases, University of Calgary, Calgary, AB, Canada.,Biochemistry and Molecular Biology, Snyder Institute for Chronic Diseases, University of Calgary, Calgary, AB, Canada
| | - Kris Chadee
- Departments of Microbiology, Immunology and Infectious Diseases, Calgary, AB, Canada.
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12
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Silva Oliveira FM, Claúdia de Carvalho Fernandes A, Henrique de Cicco Sandes S, Prata LO, Junior MA, Vilela da Silva CA, Campolina-Silva GH, Lorenzo de Jesus Oliveira M, Oliveira CA, Neumann E, Nunes ÁC, Gomes MA, Caliari MV. Co-infection by Salmonella enterica subsp. Enterica serovar typhimurium and Entamoeba dispar pathogenic strains enhances colitis and the expression of amoebic virulence factors. Microb Pathog 2021; 158:105010. [PMID: 34126224 DOI: 10.1016/j.micpath.2021.105010] [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: 11/05/2020] [Revised: 03/15/2021] [Accepted: 05/20/2021] [Indexed: 11/29/2022]
Abstract
Amebiasis is the most severe protozoan infection affecting the human intestine, and the second leading cause of death among parasitic diseases. The mechanisms of amoebic virulence factors acquisition are poorly understood, and there are few studies showing the interaction between Entamoeba dispar and bacteria. Salmonella enterica subsp. enterica serovar typhimurium is also a common cause of gastroenteritis in humans. Considering the high rates of amebiasis and salmonellosis, it is possible that these diseases may co-exist in the human intestine, leading to co-infection. Due to the scarcity of studies showing the influence of enteropathogenic bacteria on amoebic virulence, our research group proposed to evaluate the impact of S. typhimurium on E. dispar trophozoites. We assessed whether co-infection of S. typhimurium and E. dispar can change the progression of amoebic colitis, and the inflammatory response profile in the caecum mucosa, using a co-infection experimental model in rats. In vitro assays was used to investigate whether S. typhimurium induces changes in amoebic virulence phenotype. In the present work, we found that S. typhimurium co-infection exacerbates amoebic colitis and intestinal inflammation. The in vitro association of S. typhimurium and E. dispar trophozoites contributed to increase the expression of amoebic virulence factors. Also, we demonstrated, for the first time, the cysteine proteinase 5 expression in E. dispar MCR, VEJ and ADO strains, isolated in Brazil. Together, our results show that S. typhimurium and E. dispar co-infection worsens amoebic colitis, possibly by increasing the expression of amoebic virulence factors.
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Affiliation(s)
- Fabrício Marcus Silva Oliveira
- Postgraduate Program in Pathology, Institute of Biological Sciences of the Federal University of Minas Gerais, Brazil; Department of General Pathology, Institute of Biological Sciences, Federal University of Minas Gerais, Brazil.
| | | | - Sávio Henrique de Cicco Sandes
- Department of Genetics, Ecology, and Evolution, Institute of Biological Sciences, Federal University of Minas Gerais, Brazil.
| | - Luana Oliveira Prata
- Department of General Pathology, Institute of Biological Sciences, Federal University of Minas Gerais, Brazil.
| | - Mario Abatemarco Junior
- Department of Microbiology, Institute of Biological Sciences, Federal University of Minas Gerais, Brazil.
| | | | | | | | | | - Elisabeth Neumann
- Department of Microbiology, Institute of Biological Sciences, Federal University of Minas Gerais, Brazil.
| | - Álvaro Cantini Nunes
- Department of Genetics, Ecology, and Evolution, Institute of Biological Sciences, Federal University of Minas Gerais, Brazil.
| | - Maria Aparecida Gomes
- Department of Parasitology, Institute of Biological Sciences, Federal University of Minas Gerais, Brazil.
| | - Marcelo Vidigal Caliari
- Department of General Pathology, Institute of Biological Sciences, Federal University of Minas Gerais, Brazil.
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13
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Guillen N. Signals and signal transduction pathways in Entamoeba histolytica during the life cycle and when interacting with bacteria or human cells. Mol Microbiol 2020; 115:901-915. [PMID: 33249684 DOI: 10.1111/mmi.14657] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 11/22/2020] [Accepted: 11/23/2020] [Indexed: 01/17/2023]
Abstract
Entamoeba histolytica is the etiological agent of amebiasis in humans. This ameba parasite resides as a commensal in the intestine where it shares intestinal resources with the bacterial microbiome. In the intestinal ecosystem, the ameba encysts and eventually develops disease by invading the tissues. E. histolytica possesses cell surface receptors for the proper sensing of signals involved in encystation or sustaining parasite interaction with bacteria and human cells. Among those receptors are the Gal/GalNAc lectin, G protein-coupled receptors, and transmembrane kinases. In addition there are recently discovered, promising proteins, including orthologs of Toll-type receptors and β trefoil lectins. These proteins trigger a wide variety of signal transduction pathways; however, most of the players involved in the signaling pathways evoked in this parasite are unknown. This review provides an overview of amoebic receptors and their role in encystation, adherence to bacteria or human cells, as well as the reported intracellular signal transduction processes that they can trigger. This knowledge is essential for understanding the lifestyle of E. histolytica and its cytopathic effect on bacteria and human cells that are responsible for infection.
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Affiliation(s)
- Nancy Guillen
- Institut Pasteur, Centre National de la Recherche Scientifique, CNRS-ERL9195, Paris, France
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14
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Uddin MJ, Leslie JL, Petri WA. Host Protective Mechanisms to Intestinal Amebiasis. Trends Parasitol 2020; 37:165-175. [PMID: 33502317 PMCID: PMC7840892 DOI: 10.1016/j.pt.2020.09.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 09/27/2020] [Accepted: 09/28/2020] [Indexed: 12/13/2022]
Abstract
The protozoan parasite Entamoeba histolytica is the causative agent of amebiasis, an infection that manifests as colitis and, in some cases, liver abscess. A better understanding of host protective factors is key to developing an effective remedy. Recently, significant advances have been made in understanding the mechanisms of MUC2 production by goblet cells upon amebic infection, regulation of antimicrobial peptide production by Paneth cells, the interaction of commensal microbiota with immune stimulation, and host genetics in conferring protection from amebiasis. In addition to host pathways that may serve as potential therapeutic targets, significant progress has also been made with respect to development of a vaccine against amebiasis. Here, we aim to highlight the current understanding and knowledge gaps critically.
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Affiliation(s)
- Md Jashim Uddin
- Division of Infectious Diseases and International Health, Department of Medicine, University of Virginia, Charlottesville, VA, USA
| | - Jhansi L Leslie
- Division of Infectious Diseases and International Health, Department of Medicine, University of Virginia, Charlottesville, VA, USA
| | - William A Petri
- Division of Infectious Diseases and International Health, Department of Medicine, University of Virginia, Charlottesville, VA, USA.
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15
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Anti-Pathogenic Functions of Non-Digestible Oligosaccharides In Vitro. Nutrients 2020; 12:nu12061789. [PMID: 32560186 PMCID: PMC7353314 DOI: 10.3390/nu12061789] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 06/10/2020] [Accepted: 06/12/2020] [Indexed: 12/11/2022] Open
Abstract
Non-digestible oligosaccharides (NDOs), complex carbohydrates that resist hydrolysis by salivary and intestinal digestive enzymes, fulfill a diversity of important biological roles. A lot of NDOs are known for their prebiotic properties by stimulating beneficial bacteria in the intestinal microbiota. Human milk oligosaccharides (HMOs) represent the first prebiotics that humans encounter in life. Inspired by these HMO structures, chemically-produced NDO structures (e.g., galacto-oligosaccharides and chito-oligosaccharides) have been recognized as valuable food additives and exert promising health effects. Besides their apparent ability to stimulate beneficial microbial species, oligosaccharides have shown to be important inhibitors of the development of pathogenic infections. Depending on the type and structural characteristics, oligosaccharides can exert a number of anti-pathogenic effects. The most described effect is their ability to act as a decoy receptor, thereby inhibiting adhesion of pathogens. Other ways of pathogenic inhibition, such as interference with pathogenic cell membrane and biofilm integrity and DNA transcription, are less investigated, but could be equally impactful. In this review, a comprehensive overview of In vitro anti-pathogenic properties of different NDOs and associated pathways are discussed. A framework is created categorizing all anti-pathogenic effects and providing insight into structural necessities for an oligosaccharide to exert one of these effects.
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16
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Castellanos-Castro S, Bolaños J, Orozco E. Lipids in Entamoeba histolytica: Host-Dependence and Virulence Factors. Front Cell Infect Microbiol 2020; 10:75. [PMID: 32211340 PMCID: PMC7075943 DOI: 10.3389/fcimb.2020.00075] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 02/14/2020] [Indexed: 11/19/2022] Open
Abstract
Lipids are essential players in parasites pathogenesis. In particular, the highly phagocytic trophozoites of Entamoeba histolytica, the causative agent of amoebiasis, exhibit a dynamic membrane fusion and fission, in which lipids strongly participate; particularly during the overstated motility of the parasite to reach and attack the epithelia and ingest target cells. Synthesis and metabolism of lipids in this protozoan present remarkable difference with those performed by other eukaryotes. Here, we reviewed the current knowledge on lipids in E. histolytica. Trophozoites synthesize phosphatidylcholine and phosphatidylethanolamine by the Kennedy pathway; and sphingolipids, phosphatidylserine, and phosphatidylinositol, by processes similar to those used by other eukaryotes. However, trophozoites lack enzymes for cholesterol and fatty acids synthesis, which are scavenged from the host or culture medium by specific mechanisms. Cholesterol, a fundamental molecule for the expression of virulence, is transported from the medium into the trophozoites by EhNPC1 and EhNPC2 proteins. Inside cells, lipids are distributed by different pathways, including by the participation of the endosomal sorting complex required for transport (ESCRT), involved in vesicle fusion and fission. Cholesterol interacts with the phospholipid lysobisphosphatidic acid (LBPA) and EhADH, an ALIX family protein, also involved in phagocytosis. In this review, we summarize the known information on phospholipids synthesis and cholesterol transport as well as their metabolic pathways in E. histolytica; highlighting the mechanisms used by trophozoites to dispose lipids involved in the virulence processes.
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Affiliation(s)
- Silvia Castellanos-Castro
- College of Sciences and Humanities, Autonomous University of Mexico City, Mexico City, Mexico.,BioImage Analysis Unit, Pasteur Institute, Paris, France
| | - Jeni Bolaños
- Department of Infectomics and Molecular Pathogenesis, Center for Research and Advanced Studies of the National Polytechnic Institute, Mexico City, Mexico.,Centro Multidisciplinario de Estudios en Biotecnología, FMVZ, Universidad Michoacana de San Nnicolás Hidalgo, Morelia, Mexico
| | - Esther Orozco
- Department of Infectomics and Molecular Pathogenesis, Center for Research and Advanced Studies of the National Polytechnic Institute, Mexico City, Mexico
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Sharma S, Agarwal S, Bharadwaj R, Somlata, Bhattacharya S, Bhattacharya A. Novel regulatory roles of PtdIns(4,5)P2generating enzyme EhPIPKI in actin dynamics and phagocytosis ofEntamoeba histolytica. Cell Microbiol 2019; 21:e13087. [DOI: 10.1111/cmi.13087] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Accepted: 07/03/2019] [Indexed: 02/06/2023]
Affiliation(s)
- Shalini Sharma
- School of Life SciencesJawaharlal Nehru University New Delhi India
| | - Shalini Agarwal
- School of Life SciencesJawaharlal Nehru University New Delhi India
| | - Ravi Bharadwaj
- School of MedicineUMASS Medical School Worcester Massachusetts USA
| | - Somlata
- Multidisciplinary Centre for Advance Research and StudiesJamia Milia Islamia New Delhi India
| | - Sudha Bhattacharya
- School of Environmental SciencesJawaharlal Nehru University New Delhi India
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18
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Quach J, Moreau F, Sandall C, Chadee K. Entamoeba histolytica-induced IL-1β secretion is dependent on caspase-4 and gasdermin D. Mucosal Immunol 2019; 12:323-339. [PMID: 30361535 DOI: 10.1038/s41385-018-0101-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 09/21/2018] [Accepted: 10/01/2018] [Indexed: 02/04/2023]
Abstract
During invasion, Entamoeba histolytica (Eh) encounter macrophages and activate them to elicit tissue damaging pro-inflammatory responses. When Eh binds macrophages via the Gal-lectin, surface EhCP-A5 RGD sequence ligates α5β1 integrin to activate caspase-1 in a complex known as the NLRP3 inflammasome. In this study, we investigated Eh requirements underlying macrophage caspase-4 and -1 activation and the role caspase-4 and gasdermin D (GSDMD) play in augmenting pro-inflammatory cytokine responses. Caspase-4 activation was similar to caspase-1 requiring live Eh attachment via the Gal-lectin and EhCP-A5. However, unlike caspase-1, caspase-4 activation was independent of ASC and NLRP3. Using CRISPR/Cas9 gene editing of caspase-4 and -1 and GSDMD, we determined that caspase-1 and bioactive IL-1β release was highly dependent on caspase-4 activation and cleavage of GSDMD in response to Eh. Formaldehyde cross-linking to stabilize protein-protein interactions in transfected COS-7 cells stimulated with Eh revealed that caspase-4 specifically interacted with caspase-1 in a protein complex that enhanced the cleavage of caspase-1 CARD domains to augment IL-1β release. Activated caspase-4 and -1 cleaved GSDMD liberating the N-terminal p30 pore-forming fragment that caused the secretion of IL-1β. These findings reveal a novel role for caspase-4 as a sensor molecule to amplify pro-inflammatory responses when macrophage encounters Eh.
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Affiliation(s)
- Jeanie Quach
- Department of Microbiology, Immunology and Infectious Diseases, Snyder Institute for Chronic Diseases, University of Calgary, Calgary, Alberta, Canada
| | - France Moreau
- Department of Microbiology, Immunology and Infectious Diseases, Snyder Institute for Chronic Diseases, University of Calgary, Calgary, Alberta, Canada
| | - Christina Sandall
- Department of Microbiology, Immunology and Infectious Diseases, Snyder Institute for Chronic Diseases, University of Calgary, Calgary, Alberta, Canada
| | - Kris Chadee
- Department of Microbiology, Immunology and Infectious Diseases, Snyder Institute for Chronic Diseases, University of Calgary, Calgary, Alberta, Canada.
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19
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Entamoeba histolytica Alters Ileal Paneth Cell Functions in Intact and Muc2 Mucin Deficiency. Infect Immun 2018; 86:IAI.00208-18. [PMID: 29685982 DOI: 10.1128/iai.00208-18] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Accepted: 04/14/2018] [Indexed: 12/19/2022] Open
Abstract
Enteric α-defensins, termed cryptdins (Crps) in mice, and lysozymes secreted by Paneth cells contribute to innate host defense in the ileum. Antimicrobial factors, including lysozymes and β-defensins, are often embedded in luminal glycosylated colonic Muc2 mucin secreted by goblet cells that form the protective mucus layer critical for gut homeostasis and pathogen invasion. In this study, we investigated ileal innate immunity against Entamoeba histolytica, the causative agent of intestinal amebiasis, by inoculating parasites in closed ileal loops in Muc2+/+ and Muc2-/- littermates and quantifying Paneth cell localization (lysozyme expression) and function (Crp secretion). Relative to Muc2+/+ littermates, Muc2-/- littermates showed a disorganized mislocalization of Paneth cells that was diffusely distributed, with elevated lysozyme secretion in the crypts and on villi in response to E. histolytica Inhibition of E. histolytica Gal/GalNAc lectin (Gal-lectin) binding with exogenous galactose and Entamoeba histolytica cysteine proteinase 5 (EhCP5)-negative E. histolytica had no effect on parasite-induced erratic Paneth cell lysozyme synthesis. Although the basal ileal expression of Crp genes was unaffected in Muc2-/- mice in response to E. histolytica, there was a robust release of proinflammatory cytokines and Crp peptide secretions in luminal exudates that was also present in the colon. Interestingly, E. histolytica-secreted cysteine proteinases cleaved the proregion of Crp4 but not the active form. These findings define Muc2 mucin as an essential component of ileal barrier function that regulates the localization and function of Paneth cells critical for host defense against microbes.
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20
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Cornick S, Chadee K. Entamoeba histolytica: Host parasite interactions at the colonic epithelium. Tissue Barriers 2018; 5:e1283386. [PMID: 28452682 DOI: 10.1080/21688370.2017.1283386] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Entamoeba histolytica (Eh) is the protozoan parasite responsible for intestinal amebiasis and interacts dynamically with the host intestinal epithelium during disease pathogenesis. A multifaceted pathogenesis profile accounts for why 90% of individuals infected with Eh are largely asymptomatic. For 100 millions individuals that are infected each year, key interactions within the intestinal mucosa dictate disease susceptibility. The ability for Eh to induce amebic colitis and disseminate into extraintestinal organs depends on the parasite competing with indigenous bacteria and overcoming the mucus barrier, binding to host cells inducing their cell death, invasion through the mucosa and outsmarting the immune system. In this review we summarize how Eh interacts with the intestinal epithelium and subverts host defense mechanisms in disease pathogenesis.
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Affiliation(s)
- Steve Cornick
- a Department of Microbiology, Immunology and Infectious Diseases , Snyder Institute for Chronic Diseases, University of Calgary , Calgary , Alberta , Canada
| | - Kris Chadee
- a Department of Microbiology, Immunology and Infectious Diseases , Snyder Institute for Chronic Diseases, University of Calgary , Calgary , Alberta , Canada
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21
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Pineda E, Perdomo D. Entamoeba histolytica under Oxidative Stress: What Countermeasure Mechanisms Are in Place? Cells 2017; 6:cells6040044. [PMID: 29160807 PMCID: PMC5755502 DOI: 10.3390/cells6040044] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Revised: 11/17/2017] [Accepted: 11/17/2017] [Indexed: 02/06/2023] Open
Abstract
Entamoeba histolytica is the causative agent of human amoebiasis; it affects 50 million people worldwide and causes approximately 100,000 deaths per year. Entamoeba histolytica is an anaerobic parasite that is primarily found in the colon; however, for unknown reasons, it can become invasive, breaching the gut barrier and migrating toward the liver causing amoebic liver abscesses. During the invasive process, it must maintain intracellular hypoxia within the oxygenated human tissues and cellular homeostasis during the host immune defense attack when it is confronted with nitric oxide and reactive oxygen species. But how? This review will address the described and potential mechanisms available to counter the oxidative stress generated during invasion and the possible role that E. histolytica’s continuous endoplasmic reticulum (Eh-ER) plays during these events.
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Affiliation(s)
- Erika Pineda
- Laboratory of Fundamental Microbiology and Pathogenicity (MFP), University of Bordeaux, CNRS UMR-5234, 33000 Bordeaux, France.
| | - Doranda Perdomo
- Laboratory of Fundamental Microbiology and Pathogenicity (MFP), University of Bordeaux, CNRS UMR-5234, 33000 Bordeaux, France.
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22
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St-Pierre J, Moreau F, Cornick S, Quach J, Begum S, Aracely Fernandez L, Gorman H, Chadee K. The macrophage cytoskeleton acts as a contact sensor upon interaction with Entamoeba histolytica to trigger IL-1β secretion. PLoS Pathog 2017; 13:e1006592. [PMID: 28837696 PMCID: PMC5587335 DOI: 10.1371/journal.ppat.1006592] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Revised: 09/06/2017] [Accepted: 08/18/2017] [Indexed: 01/09/2023] Open
Abstract
Entamoeba histolytica (Eh) is the causative agent of amebiasis, one of the major causes of dysentery-related morbidity worldwide. Recent studies have underlined the importance of the intercellular junction between Eh and host cells as a determinant in the pathogenesis of amebiasis. Despite the fact that direct contact and ligation between Eh surface Gal-lectin and EhCP-A5 with macrophage α5β1 integrin are absolute requirements for NLRP3 inflammasome activation and IL-1β release, many other undefined molecular events and downstream signaling occur at the interface of Eh and macrophage. In this study, we investigated the molecular events at the intercellular junction that lead to recognition of Eh through modulation of the macrophage cytoskeleton. Upon Eh contact with macrophages key cytoskeletal-associated proteins were rapidly post-translationally modified only with live Eh but not with soluble Eh proteins or fragments. Eh ligation with macrophages rapidly activated caspase-6 dependent cleavage of the cytoskeletal proteins talin, Pyk2 and paxillin and caused robust release of the pro-inflammatory cytokine, IL-1β. Macrophage cytoskeletal cleavages were dependent on Eh cysteine proteinases EhCP-A1 and EhCP-A4 but not EhCP-A5 based on pharmacological blockade of Eh enzyme inhibitors and EhCP-A5 deficient parasites. These results unravel a model where the intercellular junction between macrophages and Eh form an area of highly interacting proteins that implicate the macrophage cytoskeleton as a sensor for Eh contact that leads downstream to subsequent inflammatory immune responses. The protozoan parasite Entamoeba histolytica can establish an enteric infection in human hosts that leads to symptoms ranging from diarrhea to abscesses in the liver and the brain. Host susceptibility to amebic infection is in part determined by the quality and potency of the host immune response that occurs once the parasite overcomes the mucus bilayers and colonic epithelial barriers, and invades underlying tissues. At the cellular level, one of the key events that shape the inflammatory response occurs during direct parasite interaction with host macrophages via surface proteins. The ensuing cascades of intracellular signaling events have only partly been uncovered. Interestingly, only direct interaction between live parasites and macrophages, as opposed to soluble factors or dead parasites, is a prerequisite to the generation of a prompt raging pro-inflammatory response. We have sought to further elucidate the mechanisms by which macrophages distinguish live parasites and found that the macrophage cell skeleton undergoes rapid significant alteration upon Eh contact. Furthermore, we uncovered a previously unknown role for two Eh enzymes in triggering macrophage pro-inflammatory responses. Through this work, we gain a better understanding of the molecular interactions that occur at the macrophage-ameba interface that regulate host inflammatory responses.
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Affiliation(s)
- Joëlle St-Pierre
- Department of Microbiology, Immunology and Infectious Diseases, Snyder Institute for Chronic Diseases, University of Calgary, Calgary, Alberta, Canada
| | - France Moreau
- Department of Microbiology, Immunology and Infectious Diseases, Snyder Institute for Chronic Diseases, University of Calgary, Calgary, Alberta, Canada
| | - Steve Cornick
- Department of Microbiology, Immunology and Infectious Diseases, Snyder Institute for Chronic Diseases, University of Calgary, Calgary, Alberta, Canada
| | - Jeanie Quach
- Department of Microbiology, Immunology and Infectious Diseases, Snyder Institute for Chronic Diseases, University of Calgary, Calgary, Alberta, Canada
| | - Sharmin Begum
- Department of Microbiology, Immunology and Infectious Diseases, Snyder Institute for Chronic Diseases, University of Calgary, Calgary, Alberta, Canada
| | - Luz Aracely Fernandez
- Department of Microbiology, Immunology and Infectious Diseases, Snyder Institute for Chronic Diseases, University of Calgary, Calgary, Alberta, Canada
| | - Hayley Gorman
- Department of Microbiology, Immunology and Infectious Diseases, Snyder Institute for Chronic Diseases, University of Calgary, Calgary, Alberta, Canada
| | - Kris Chadee
- Department of Microbiology, Immunology and Infectious Diseases, Snyder Institute for Chronic Diseases, University of Calgary, Calgary, Alberta, Canada
- * E-mail:
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23
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Role of Eosinophils and Tumor Necrosis Factor Alpha in Interleukin-25-Mediated Protection from Amebic Colitis. mBio 2017; 8:mBio.02329-16. [PMID: 28246365 PMCID: PMC5347349 DOI: 10.1128/mbio.02329-16] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The parasite Entamoeba histolytica is a cause of diarrhea in infants in low-income countries. Previously, it was shown that tumor necrosis factor alpha (TNF-α) production was associated with increased risk of E. histolytica diarrhea in children. Interleukin-25 (IL-25) is a cytokine that is produced by intestinal epithelial cells that has a role in maintenance of gut barrier function and inhibition of TNF-α production. IL-25 expression was decreased in humans and in the mouse model of amebic colitis. Repletion of IL-25 blocked E. histolytica infection and barrier disruption in mice, increased gut eosinophils, and suppressed colonic TNF-α. Depletion of eosinophils with anti-Siglec-F antibody prevented IL-25-mediated protection. In contrast, depletion of TNF-α resulted in resistance to amebic infection. We concluded that IL-25 provides protection from amebiasis, which is dependent upon intestinal eosinophils and suppression of TNF-α. The intestinal epithelial barrier is important for protection from intestinal amebiasis. We discovered that the intestinal epithelial cytokine IL-25 was suppressed during amebic colitis in humans and that protection could be restored in the mouse model by IL-25 administration. IL-25 acted via eosinophils and suppressed TNF-α. This work illustrates a previously unrecognized pathway of innate mucosal immune response.
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Singh RS, Walia AK, Kanwar JR, Kennedy JF. Amoebiasis vaccine development: A snapshot on E. histolytica with emphasis on perspectives of Gal/GalNAc lectin. Int J Biol Macromol 2016; 91:258-68. [DOI: 10.1016/j.ijbiomac.2016.05.043] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Revised: 05/10/2016] [Accepted: 05/11/2016] [Indexed: 01/10/2023]
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25
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Singh RS, Walia AK, Kanwar JR. Protozoa lectins and their role in host–pathogen interactions. Biotechnol Adv 2016; 34:1018-1029. [DOI: 10.1016/j.biotechadv.2016.06.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Revised: 06/02/2016] [Accepted: 06/02/2016] [Indexed: 11/29/2022]
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26
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Yadav R, Verma K, Chandra M, Mukherjee M, Datta S. Biophysical studies on calcium and carbohydrate binding to carbohydrate recognition domain of Gal/GalNAc lectin fromEntamoeba histolytica: insights into host cell adhesion. J Biochem 2016; 160:177-86. [DOI: 10.1093/jb/mvw024] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Accepted: 03/08/2016] [Indexed: 11/14/2022] Open
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Perdomo D, Manich M, Syan S, Olivo-Marin JC, Dufour AC, Guillén N. Intracellular traffic of the lysine and glutamic acid rich protein KERP1 reveals features of endomembrane organization in Entamoeba histolytica. Cell Microbiol 2016; 18:1134-52. [PMID: 26857352 DOI: 10.1111/cmi.12576] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2015] [Revised: 01/06/2016] [Accepted: 02/01/2016] [Indexed: 12/12/2022]
Abstract
The development of amoebiasis is influenced by the expression of the lysine and glutamic acid rich protein 1 (KERP1), a virulence factor involved in Entamoeba histolytica adherence to human cells. Up to date, it is unknown how the protein transits the parasite cytoplasm towards the plasma membrane, specially because this organism lacks a well-defined endoplasmic reticulum (ER) and Golgi apparatus. In this work we demonstrate that KERP1 is present at the cell surface and in intracellular vesicles which traffic in a pathway that is independent of the ER-Golgi anterograde transport. The intracellular displacement of vesicles enriched in KERP1 relies on the actin-rich cytoskeleton activities. KERP1 is also present in externalized vesicles deposited on the surface of human cells. We further report the interactome of KERP1 with its association to endomembrane components and lipids. The model for KERP1 traffic here proposed hints for the first time elements of the endocytic and exocytic paths of E. histolytica.
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Affiliation(s)
- Doranda Perdomo
- Cell Biology of Parasitism Unit, Institut Pasteur, Paris, France.,INSERM U786, Paris, France.,Sorbonne Paris Cité, Cellule Pasteur, Université Paris Diderot, Paris, France
| | - Maria Manich
- Cell Biology of Parasitism Unit, Institut Pasteur, Paris, France.,INSERM U786, Paris, France
| | - Sylvie Syan
- Cell Biology of Parasitism Unit, Institut Pasteur, Paris, France.,INSERM U786, Paris, France
| | | | - Alexandre C Dufour
- Bioimage Analysis Unit, Institut Pasteur, Paris, France.,CNRS UMR 3691, Paris, France
| | - Nancy Guillén
- Cell Biology of Parasitism Unit, Institut Pasteur, Paris, France.,INSERM U786, Paris, France
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Rastew E, Morf L, Singh U. Entamoeba histolytica rhomboid protease 1 has a role in migration and motility as validated by two independent genetic approaches. Exp Parasitol 2015; 154:33-42. [PMID: 25889553 DOI: 10.1016/j.exppara.2015.04.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Revised: 02/24/2015] [Accepted: 04/08/2015] [Indexed: 11/25/2022]
Abstract
Rhomboid proteins represent a recently discovered family of intramembrane proteases present in a broad range of organisms and with increasing links to human diseases. The enteric parasite Entamoeba histolytica has evolved multiple mechanisms to adapt to the human host environment and establish infection. Our recent studies identified EhROM1 as a functional E. histolytica rhomboid protease with roles in adhesion to and phagocytosis of host cells. Since those studies were performed in a non-virulent strain, roles in parasite virulence could not be assessed. We focused this study on the comparison and validation of two genetic manipulation techniques: overexpression of a dominant-negative catalytic mutant of EhROM1 and knock down of EhROM1 using a RNAi-based silencing approach followed by functional studies of phenotypic analyses in virulent parasites. Both the EhROM1 catalytic mutant and parasites with EhROM1 downregulation were reduced in cytotoxicity, hemolytic activity, and directional and non-directional transwell migration. Importantly, the role for EhROM1 in cell migration mimics similar roles for rhomboid proteases from mammalian and apicomplexan systems. However, the EhROM1 catalytic mutant and EhROM1 downregulation parasites had different phenotypes for erythrophagocytosis, while complement resistance was not affected in either strain. In summary, in this study we genetically manipulated E. histolytica rhomboid protease EhROM1 by two different approaches and identified similarly attenuated phenotypes by both approaches, suggesting a novel role for EhROM1 in amebic motility.
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Affiliation(s)
- Elena Rastew
- Department of Internal Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Laura Morf
- Department of Internal Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Upinder Singh
- Department of Internal Medicine, Stanford University School of Medicine, Stanford, CA, USA; Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, USA.
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Aguirre García M, Gutiérrez-Kobeh L, López Vancell R. Entamoeba histolytica: adhesins and lectins in the trophozoite surface. Molecules 2015; 20:2802-15. [PMID: 25671365 PMCID: PMC6272351 DOI: 10.3390/molecules20022802] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2014] [Accepted: 01/13/2015] [Indexed: 01/06/2023] Open
Abstract
Entamoeba histolytica is the causative agent of amebiasis in humans and is responsible for 100,000 deaths annually, making it the third leading cause of death due to a protozoan parasite. Pathogenesis appears to result from the potent cytotoxic activity of the parasite, which kills host cells within minutes. Although the mechanism is unknown, it is well established to be contact-dependent. The life cycle of the parasite alternates with two forms: the resistant cyst and the invasive trophozoite. The adhesive interactions between the parasite and surface glycoconjugates of host cells, as well as those lining the epithelia, are determinants for invasion of human tissues, for its cytotoxic activity, and finally for the outcome of the disease. In this review we present an overview of the information available on the amebic lectins and adhesins that are responsible of those adhesive interactions and we also refer to their effect on the host immune response. Finally, we present some concluding remarks and perspectives in the field.
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Affiliation(s)
- Magdalena Aguirre García
- Departmento de Medicina Experimental, Facultad de Medicina, Universidad Nacional Autónoma de México, Dr. Balmis #148, Col. Doctores, C.P. 06726 Mexico, D.F., Mexico.
| | - Laila Gutiérrez-Kobeh
- Departmento de Medicina Experimental, Facultad de Medicina, Universidad Nacional Autónoma de México, Dr. Balmis #148, Col. Doctores, C.P. 06726 Mexico, D.F., Mexico.
| | - Rosario López Vancell
- Departmento de Medicina Experimental, Facultad de Medicina, Universidad Nacional Autónoma de México, Dr. Balmis #148, Col. Doctores, C.P. 06726 Mexico, D.F., Mexico.
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[Colonic perforation due to invasive amebic colitis during anti-TNF therapy for spondyloarthritis]. REVISTA BRASILEIRA DE REUMATOLOGIA 2014; 54:483-5. [PMID: 25458030 DOI: 10.1016/j.rbr.2013.09.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2013] [Revised: 09/05/2013] [Accepted: 09/27/2013] [Indexed: 11/20/2022] Open
Abstract
TNF blockade has been successful in the treatment of some rheumatic diseases such as spondyloarthritis. Many infectious complications have been reported with anti-TNF therapy, mainly bacterial, mycobacterial, viral and fungal infections. Entamoeba histolytica is an extracellular protozoan parasite that mainly causes colitis and hepatic abscess; bowel perforation is an uncommon complication with high mortality. TNF is considered the principal mediator of cell immunity against amebiasis. Initially, it is chemotactic to E. histolytica, enhancing its adherence to enterocyte via galactose inhibitable lectin, and then activating macrophages to kill ameba though the release of NO, so that TNF blocking could be harmful, increasing amebic virulence. We describe the case of a 46-year-old woman with spondyloarthritis who presented a colonic perforation due to invasive amebic colitis during anti-TNF use.
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Mortimer L, Moreau F, Cornick S, Chadee K. Gal-lectin-dependent contact activates the inflammasome by invasive Entamoeba histolytica. Mucosal Immunol 2014; 7:829-41. [PMID: 24253103 DOI: 10.1038/mi.2013.100] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Revised: 10/16/2013] [Accepted: 10/21/2013] [Indexed: 02/04/2023]
Abstract
Entamoeba histolytica (Eh) is an extracellular protozoan parasite of the human colon, which occasionally breaches the intestinal barrier. Eradicating ameba that invades is essential for host survival. A defining but uncharacterized feature of amebic invasion is direct contact between ameba and host cells. This event corresponds with a massive pro-inflammatory response. To date, pathogen recognition receptors (PRRs) that are activated by contact with viable Eh are unknown. Here we show that the innate immune system responds in a qualitatively different way to contact with viable Eh vs. soluble ligands produced by viable or dead ameba. This unique Eh Gal-lectin contact-dependent response in macrophages was mediated by activation of the inflammasome. Soluble native Gal-lectin did not induce inflammasome activation, but was sufficient for transcriptional priming of the inflammasome and non-inflammasome-dependent pro-inflammatory cytokine release. We conclude the inflammasome is a pathogenicity sensor for invasive Eh and identify for the first time a PRR that specifically responds to contact with intact parasites in a manner that accords with scale immune response to parasite invasion.
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Affiliation(s)
- L Mortimer
- Faculty of Medicine, Department of Microbiology, Immunology and Infectious Diseases, Snyder Institute for Chronic Diseases, Gastrointestinal Research Group, University of Calgary, Calgary, Alberta, Canada
| | - F Moreau
- Faculty of Medicine, Department of Microbiology, Immunology and Infectious Diseases, Snyder Institute for Chronic Diseases, Gastrointestinal Research Group, University of Calgary, Calgary, Alberta, Canada
| | - S Cornick
- Faculty of Medicine, Department of Microbiology, Immunology and Infectious Diseases, Snyder Institute for Chronic Diseases, Gastrointestinal Research Group, University of Calgary, Calgary, Alberta, Canada
| | - K Chadee
- Faculty of Medicine, Department of Microbiology, Immunology and Infectious Diseases, Snyder Institute for Chronic Diseases, Gastrointestinal Research Group, University of Calgary, Calgary, Alberta, Canada
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Entamoeba histolytica contains an occludin-like protein that can alter colonic epithelial barrier function. PLoS One 2013; 8:e73339. [PMID: 24058468 PMCID: PMC3772840 DOI: 10.1371/journal.pone.0073339] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Accepted: 07/29/2013] [Indexed: 01/09/2023] Open
Abstract
The exact mechanism by which Entamoeba histolytica disrupts the human colonic epithelium and invades the mucosa has yet to be clearly elucidated. E. histolytica produces a diverse array of putative virulent factors such as glycosidase, cysteine proteinases and amebapore that can modulate and/or disrupt epithelial barrier functions. However, it is currently thought that E. histolytica produces numerous other molecules and strategies to disrupt colonic mucosal defenses. In this study, we document a putative mechanism whereby the parasite alters the integrity of human epithelium by expressing a cognate tight junction protein of the host. We detected this protein as “occludin-like” as revealed by immunoblotting and immunoprecipitation studies and visualization by confocal microscopy using antibodies highly specific for human occludin. We propose that E. histolytica occludin-like protein might displace mucosal epithelial occludin-occludin tight junction interactions resulting in epithelial disruption analogous to sub mucosal human dendritic cells sampling luminal contents. These results indicate that E. histolytica occludin is a putative virulent component that can play a role in the pathogenesis of intestinal amebiasis.
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Barroso L, Abhyankar M, Noor Z, Read K, Pedersen K, White R, Fox C, Petri WA, Lyerly D. Expression, purification, and evaluation of recombinant LecA as a candidate for an amebic colitis vaccine. Vaccine 2013; 32:1218-24. [PMID: 23827311 DOI: 10.1016/j.vaccine.2013.06.056] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2013] [Revised: 06/06/2013] [Accepted: 06/19/2013] [Indexed: 11/25/2022]
Abstract
Entamoeba histolytica, which causes amebic colitis and liver abscess, is considered a major enteric pathogen in residents and travelers to developing countries where the disease is endemic. Interaction of this protozoan parasite with the intestine is mediated through the binding of the trophozoite stage to intestinal mucin and epithelium via a galactose and N-acetyl-d-galactosamine (Gal/GalNAc) lectin comprised of a disulfide linked heavy (ca. 180 kDa) and light chain (ca. 35 kDa) and a noncovalently bound intermediate subunit (ca. 150 kDa). Our efforts to develop a vaccine against this pathogen have focused on an internal 578 amino acid fragment, designated LecA, located within the cysteine-rich region of the heavy chain subunit because: (i) it is a major target of adherence-blocking antibodies of seropositive individuals and (ii) vaccination with his-tagged LecA provides protection in animal models. We developed a purification process for preparing highly purified non-tagged LecA using a codon-optimized gene expressed in Escherichia coli. The process consisted of: (i) cell lysis, collection and washing of inclusion bodies; (ii) solubilization and refolding of denatured LecA; and (iii) a polishing gel filtration step. The purified fragment existed primarily as a random coil with β-sheet structure, contained low endotoxin and nucleic acid, was highly immunoreactive, and elicited antibodies that recognized native lectin and that inhibited in vitro adherence of trophozoites to CHO cells. Immunization of CBA mice with LecA resulted in significant protection against cecal colitis. Our procedure yields sufficient amounts of highly purified LecA for future studies on stability, immunogenicity, and protection with protein-adjuvant formulations.
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Affiliation(s)
- L Barroso
- TECHLAB, Inc., 2001 Kraft Drive, Blacksburg, VA 24060-6158, USA
| | - M Abhyankar
- Division of Infectious Diseases and International Health University of Virginia Health System, Carter Harrison Building, Room 1709A, 345 Crispell Drive, P.O. Box 801340, Charlottesville, VA 22908-1340, USA
| | - Z Noor
- Division of Infectious Diseases and International Health University of Virginia Health System, Carter Harrison Building, Room 1709A, 345 Crispell Drive, P.O. Box 801340, Charlottesville, VA 22908-1340, USA
| | - K Read
- TECHLAB, Inc., 2001 Kraft Drive, Blacksburg, VA 24060-6158, USA
| | - K Pedersen
- TECHLAB, Inc., 2001 Kraft Drive, Blacksburg, VA 24060-6158, USA
| | - R White
- TECHLAB, Inc., 2001 Kraft Drive, Blacksburg, VA 24060-6158, USA
| | - C Fox
- Infectious Disease Research Institute, Seattle, WA, USA
| | - W A Petri
- Division of Infectious Diseases and International Health University of Virginia Health System, Carter Harrison Building, Room 1709A, 345 Crispell Drive, P.O. Box 801340, Charlottesville, VA 22908-1340, USA
| | - D Lyerly
- TECHLAB, Inc., 2001 Kraft Drive, Blacksburg, VA 24060-6158, USA.
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Kato K, Takegawa Y, Ralston KS, Gilchrist CA, Hamano S, Petri WA, Shinohara Y. Sialic acid-dependent attachment of mucins from three mouse strains to Entamoeba histolytica. Biochem Biophys Res Commun 2013; 436:252-8. [PMID: 23726913 DOI: 10.1016/j.bbrc.2013.05.085] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Accepted: 05/21/2013] [Indexed: 01/12/2023]
Abstract
Mouse strain-specific differences in the carbohydrate composition of intestinal mucins were hypothesized to account for strain-dependent susceptibility to Entamoeba histolytica. To test this hypothesis, intestinal mucins from susceptible and resistant inbred strains of mice were analyzed for their O-glycan content and for their ability to inhibit amoebic adherence to (GalNAc)12-27-HSA neo-glycoproteins. The results showed that the colorectal mucin O-glycan of susceptible CBA mice was lower in sialic acid content than that of resistant C57BL/6 and BALB/c mice. Mucins from CBA mice were more potent inhibitors of E. histolytica adherence to neo-glycoproteins than were mucins from C57BL/6 or BALB/c mice. Consistent with the role of terminal Gal/GalNAc as a receptor for amoebic adherence, sialidase treatment of C57BL/6 and BALB/c colorectal mucins increased their ability to inhibit E. histolytica adherence to the neo-glycoproteins. These results provide evidence of mouse strain-specific differences in the sialic acids content of mucin O-glycans. These dissimilarities likely contribute to the differential susceptibility of the three mouse strains to E. histolytica infection.
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Affiliation(s)
- Kentaro Kato
- Department of Parasitology, Institute of Tropical Medicine (NEKKEN), Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan.
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Manna D, Grewal JS, Sarkar B, Maiti S, Lohia A. Polyunsaturated fatty acids induce polarized submembranous F-actin aggregates and killEntamoeba histolytica. Cytoskeleton (Hoboken) 2013; 70:260-8. [PMID: 23568815 DOI: 10.1002/cm.21105] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2012] [Accepted: 02/26/2013] [Indexed: 12/28/2022]
Affiliation(s)
- Dipak Manna
- Department of Biochemistry; Bose Institute; Kolkata; West Bengal; India
| | | | - Bidyut Sarkar
- Department of Chemical Sciences; Tata Institute of Fundamental Research; Mumbai; Maharashtra; India
| | - Sudipta Maiti
- Department of Chemical Sciences; Tata Institute of Fundamental Research; Mumbai; Maharashtra; India
| | - Anuradha Lohia
- Department of Biochemistry; Bose Institute; Kolkata; West Bengal; India
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Proteases from Entamoeba spp. and Pathogenic Free-Living Amoebae as Virulence Factors. J Trop Med 2013; 2013:890603. [PMID: 23476670 PMCID: PMC3582061 DOI: 10.1155/2013/890603] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2012] [Accepted: 11/28/2012] [Indexed: 02/01/2023] Open
Abstract
The standard reference for pathogenic and nonpathogenic amoebae is the human parasite Entamoeba histolytica; a direct correlation between virulence and protease expression has been demonstrated for this amoeba. Traditionally, proteases are considered virulence factors, including those that produce cytopathic effects in the host or that have been implicated in manipulating the immune response. Here, we expand the scope to other amoebae, including less-pathogenic Entamoeba species and highly pathogenic free-living amoebae. In this paper, proteases that affect mucin, extracellular matrix, immune system components, and diverse tissues and cells are included, based on studies in amoebic cultures and animal models. We also include proteases used by amoebae to degrade iron-containing proteins because iron scavenger capacity is currently considered a virulence factor for pathogens. In addition, proteases that have a role in adhesion and encystation, which are essential for establishing and transmitting infection, are discussed. The study of proteases and their specific inhibitors is relevant to the search for new therapeutic targets and to increase the power of drugs used to treat the diseases caused by these complex microorganisms.
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Juárez-Hernández LJ, García-Pérez RM, Salas-Casas A, García-Rivera G, Orozco E, Rodríguez MA. Entamoeba histolytica: the over expression of a mutated EhRabB protein produces a decrease of in vitro and in vivo virulence. Exp Parasitol 2012; 133:339-45. [PMID: 23268174 DOI: 10.1016/j.exppara.2012.12.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2010] [Revised: 12/11/2012] [Accepted: 12/13/2012] [Indexed: 12/25/2022]
Abstract
Vesicular trafficking, which is implicated in secretion of cytolytic molecules as well as in phagocytosis, plays an important role in the pathogenic mechanism of Entamoeba histolytica, the protozoan parasite causative of human amoebiasis. Thus, Rab GTPases, that are key regulators of vesicle trafficking, should be considered as molecules involved in the parasite virulence. EhRabB is a Rab protein located in cytoplasmic vesicles that are translocated to phagocytic mouths during ingestion of target cells, suggesting that this Rab protein is involved in phagocytosis. To prove this hypothesis, we over expressed the wild type EhrabB gene and a mutant gene encoding for a protein (RabBN118I) unable to bind guanine nucleotides and therefore constitutively inactive. The over expression of the mutated protein in E. histolytica trophozoites provoked a dominant negative effect, reflected in a significant decrease of both phagocytosis and cytopathic effect as well as in a failure to produce hepatic abscesses in hamsters. These results confirm that EhRabB is involved in phagocytosis and virulence of E. histolytica.
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Affiliation(s)
- L J Juárez-Hernández
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del IPN, A.P. 14-740, México D.F. 07000, Mexico
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Abhyankar MM, Shrimal S, Gilchrist CA, Bhattacharya A, Petri WA. The Entamoeba histolytica serum-inducible transmembrane kinase EhTMKB1-9 is involved in intestinal amebiasis. INTERNATIONAL JOURNAL FOR PARASITOLOGY-DRUGS AND DRUG RESISTANCE 2012; 2:243-248. [PMID: 23267432 DOI: 10.1016/j.ijpddr.2012.01.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
Abstract
Entamoeba histolytica possesses a family of approximately 100 putative transmembrane kinases (TMKs), indicating that the parasite has an extensive means of environmental sensing. The TMKs have been divided into nine sub-groups based on the sequence composition of their intracellular kinase as well as extracellular cysteine-rich domains. EhTMKB1-9 has been recently shown to be expressed in proliferating trophozoites and induced by serum. Interference with EhTMKB1-9 by antisense RNA knockdown or expression of a truncated protein diminished proliferation, adhesion and cytotoxicity. Here we report the involvement of EhTMKB1-9 in phagocytosis and its virulence function in the formation of amebic colitis. Trophozoites induced to express higher levels of wild type EhTMKB1-9 showed increased capacity for endocytosis. In contrast, cells compromised for the EhTMKB1-9 expression through antisense inhibition showed significantly lower levels of phagocytosis and endocytosis under the experimental conditions. The role of EhTMKB1-9 as a virulence factor was studied using animal models of amebiasis. Trophozoites expressing high levels of mutant protein lacking the kinase domain showed a competitive disadvantage with regard to survival as well as invasive phenotype in the murine model of amebic colitis. The same parasites however, were not compromised in their ability to generate abscess in the gerbil model of invasive liver amebiasis. EhTMKB1-9 is the second member from the "B" group of EhTMKs which seems to be deployed by the parasite during intestinal infection. TMKs are attractive targets for drug development because of their requirement in virulence and proliferation.
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Affiliation(s)
- Mayuresh M Abhyankar
- Division of Infectious Diseases and International Health, School of Medicine, University of Virginia Health System, Charlottesville, VA 22908, USA
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40
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Rastew E, Vicente JB, Singh U. Oxidative stress resistance genes contribute to the pathogenic potential of the anaerobic protozoan parasite, Entamoeba histolytica. Int J Parasitol 2012; 42:1007-15. [PMID: 23009748 DOI: 10.1016/j.ijpara.2012.08.006] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Revised: 08/21/2012] [Accepted: 08/27/2012] [Indexed: 01/06/2023]
Abstract
The protozoan parasite, Entamoeba histolytica, invades the host colon causing significant tissue destruction and inflammation. Upon host infection, the parasite is confronted with reactive oxygen and nitrogen species (ROS/RNS) that cause large-scale changes in gene expression profiles, which likely support the parasite's adaptation to the host environment. We have previously identified oxidative and nitrosative stress responsive genes using whole-genome expression profiling. Functional studies on two such genes are now reported and demonstrate that they have roles in parasite virulence. EHI_056680 encodes a small hypothetical protein named E. histolytica stress-induced adhesion factor (EhSIAF); EHI_188210 encodes a putative phospholipid transporting P-type ATPase/flippase (EhPTPA). Over-expression of each protein in E. histolytica trophozoites enhanced parasite survival in response to oxidative stress. Exposure to oxidative and nitrosative stress did not affect the localization of EhSIAF or EhPTPA but markedly increased EhPTPA protein levels. Interestingly, over-expression of each gene resulted in parasites with increased adherence to healthy mammalian cells, but increased adherence to apoptotic cells was noted only in EhSIAF over-expressing parasites. However, despite having increased adherence to both healthy and apoptotic host cells, EhSIAF-over-expressing parasites were reduced in their ability to destroy mammalian cell monolayers, raising the intriguing possibility that EhSIAF over-expression caused signaling defects or resulted in a dominant negative phenotype. Over-expression of EhSIAF and EhPTPA also resulted in decreased motility in a transwell motility assay. Thus, we have confirmed that two genes that are upregulated by ROS confer increased resistance to oxidative stress and have identified an unexpected role of EhSIAF and EhPTPA in host cell adherence and a role of EhSIAF in parasite virulence. Our data imply that stress response genes may play multi-factorial roles in amoebic pathogenesis.
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Affiliation(s)
- Elena Rastew
- Department of Internal Medicine, Stanford University School of Medicine, Stanford, CA, USA
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41
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Christy NCV, Buss SN, Petri WA. Common pathways for receptor-mediated ingestion of Escherichia coli and LDL cholesterol by Entamoeba histolytica regulated in part by transmembrane kinase 39. Int J Parasitol 2012; 42:393-400. [PMID: 22619755 DOI: 10.1016/j.ijpara.2012.02.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The single-celled parasite, Entamoeba histolytica, is an enteric pathogen that ingests bacteria and host cells. Inhibition of phagocytosis renders the parasite avirulent. The ligand/receptor interactions that allow E. histolytica to phagocytose are not well understood. We hypothesised that E. histolytica trophozoites might accomplish ingestion through the utilisation of a scavenger receptor for cholesterol. Here we show that acetylated low density lipoprotein cholesterol was phagocytosed by amoebae via receptor mediated mechanisms. Acetylated low density lipoprotein cholesterol competitively inhibited by 31 ± 1.3% (P < 0.005) the ingestion of Escherichia coli, but not erythrocytes and Jurkat T lymphocytes, suggesting a partially redundant phagocytic pathway for E. coli and cholesterol. Inducible expression ofa signalling-dead dominant-negative version of E. histolytica transmembrane kinase 39 inhibited ingestion of E. coli by 55 ± 3% (P < 0.005) but not LDL particles. We concluded that ingestion of E. coli was regulated by TMK39 and partially shared the acetylated low density lipoprotein cholesterol uptake pathway.
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Affiliation(s)
- Nathaniel C V Christy
- Department of Microbiology, Immunology and Cancer Biology, Division of Infectious Diseases and International Health, University of Virginia, Charlottesville, VA 22908, USA
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42
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Suzuki J, Kobayashi S, Imada M, Tolba ME, Takeuchi T. Characterization of a novel Entamoeba histolytica strain from Burkina Faso, Africa, possessing a unique hexokinase-2 gene. Parasite 2012; 18:287-94. [PMID: 22091458 PMCID: PMC3677594 DOI: 10.1051/parasite/2011184287] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
An Entamoeba histolytica strain (BF-841 cl1) that originated from Burkina Faso, Africa presented with novel, polymorphic genotypes of the serine-rich E. histolytica protein and the anodic hexokinase-2 (HXK-2) isoenzyme band, which showed less electrophoretic mobility than that of an E. histolytica reference strain [HM-1:IMSS cl6 (zymodeme (Z)-II)] by starch gel electrophoresis and isoelectric focusing (IEF). The HXK-2 gene of BF-841 cl1 had amino acid variations at four positions compared to the sequence of HM-1: IMSS cl6. These variations were absent from the sequences of four other E. histolytica strains with different zymodemes [KU27 (Z-II), SAW1627 (Z-IIα-), SAW755CR clB (Z-XIV), and KU2 (Z-XIX)]. The results of IEF showed no difference in the substrate specificity of HXK (HXK-1 and HXK-2) between BF-841 cl1 and the three reference E. histolytica strains (HM-1:IMSS cl6, SAW755 clB, and KU27). It was also confirmed that BF-841 cl1 was able to form liver abscesses in Syrian hamsters.
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Affiliation(s)
- J Suzuki
- Division of Clinical Microbiology, Department of Microbiology, Tokyo Metropolitan Institute of Public Health, Tokyo, Japan
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Entamoeba histolytica cell surface calreticulin binds human c1q and functions in amebic phagocytosis of host cells. Infect Immun 2012; 80:2008-18. [PMID: 22473608 DOI: 10.1128/iai.06287-11] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Phagocytosis of host cells is characteristic of tissue invasion by the intestinal ameba Entamoeba histolytica, which causes amebic dysentery and liver abscesses. Entamoeba histolytica induces host cell apoptosis and uses ligands, including C1q, on apoptotic cells to engulf them. Two mass spectrometry analyses identified calreticulin in amebic phagosome preparations, and, in addition to its function as an endoplasmic reticulum chaperone, calreticulin is believed to be the macrophage receptor for C1q. The purpose of this study was to determine if calreticulin functions as an E. histolytica C1q receptor during phagocytosis of host cells. Calreticulin was localized to the surface of E. histolytica during interaction with both Jurkat lymphocytes and erythrocytes and was present in over 75% of phagocytic cups during amebic erythrophagocytosis. Presence of calreticulin on the cell surface was further demonstrated using a method that selectively biotinylated cell surface proteins and by flow cytometry using trophozoites overexpressing epitope-tagged calreticulin. Regulated overexpression of calreticulin increased E. histolytica's ability to phagocytose apoptotic lymphocytes and calcium ionophore-treated erythrocytes but had no effect on amebic adherence to or destruction of cell monolayers or surface expression of the GalNAc lectin and serine-rich E. histolytica protein (SREHP) receptors. Finally, E. histolytica calreticulin bound specifically to apoptotic lymphocytes and to human C1q. Collectively, these data implicate cell surface calreticulin as a receptor for C1q during E. histolytica phagocytosis of host cells.
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Control of Entamoeba histolytica adherence involves metallosurface protease 1, an M8 family surface metalloprotease with homology to leishmanolysin. Infect Immun 2012; 80:2165-76. [PMID: 22451519 DOI: 10.1128/iai.06389-11] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Invasive amebiasis due to Entamoeba histolytica infection is an important cause of morbidity in developing countries. The E. histolytica genome contains two homologues to the metalloprotease leishmanolysin gene, Entamoeba histolytica MSP-1 (EhMSP-1) and EhMSP-2, while the commensal ameba Entamoeba dispar has lost EhMSP-1. In this study, we sought to characterize E. histolytica metallosurface protease 1 (EhMSP-1). Using immunoprecipitation and a model substrate, we found that EhMSP-1 was a functional metalloprotease. Confocal microscopy and flow cytometry revealed that EhMSP-1 localized to the cell surface and revealed the existence of distinct, nonclonal trophozoite populations with high and low EhMSP-1 surface abundance that became synchronized following serum starvation. Phenotypic assays were performed after silencing EhMSP-1. Adherence of EhMSP-1-deficient trophozoites to tissue culture cell monolayers was more than five times greater than that of control amebas, but surface staining of several antigens, including the galactose adherence lectin, was unchanged. EhMSP-1 silencing similarly increased adherence to both viable and apoptotic Jurkat lymphocytes. Tissue culture cell monolayer destruction was reduced by EhMSP-1 silencing, although it was blocked almost completely by inhibiting cysteine proteases. Consistent with a primary defect in regulation of amebic adherence, EhMSP-1 silencing also resulted in reduced mobility on tissue culture cell monolayers and in increased phagocytosis. In conclusion, EhMSP-1 was shown to be a surface metalloprotease involved in regulation of amebic adherence, with additional effects on cell motility, cell monolayer destruction, and phagocytosis.
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Abd Alla MD, Wolf R, White GL, Kosanke SD, Cary D, Verweij JJ, Zhang MJ, Ravdin JI. Efficacy of a Gal-lectin subunit vaccine against experimental Entamoeba histolytica infection and colitis in baboons (Papio sp.). Vaccine 2012; 30:3068-75. [PMID: 22406457 DOI: 10.1016/j.vaccine.2012.02.066] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2011] [Revised: 02/03/2012] [Accepted: 02/25/2012] [Indexed: 11/30/2022]
Abstract
To determine the efficacy of a Gal-lectin based intranasal synthetic peptide vaccine, we developed a new experimental primate model of Entamoeba histolytica intestinal infection. Release of xenic E. histolytica trophozoites (5×10(6)) into the small bowel of baboons (Papio sp.) resulted in a rapid intestinal anti-amebic antibody response and a brief infection; however, release of trophozoites directly into the cecum (5 baboons) elicited a sustained E. histolytica infection, as determined by quantitative fecal PCR, and an ulcerative, inflammatory colitis observed on colonoscopy and histopathology. In three controlled experiments, baboons received four immunizations at seven day intervals of 1600 μg of the vaccine/nostril, with Cholera toxin, 20 μg/nostril as adjuvant; vaccinated (n=6) and control baboons (n=6) baboons were then challenged via colonoscopy with xenic trophozoites (5×10(6)). During 90 days of follow up, 250 of 415 (60.24%) fecal samples in control baboons had a (+) PCR for E. histolytica, compared to only 36 of 423 (8.51%) samples from vaccinated baboons (P<0.001). All 6 vaccinated baboons were free of infection by the 51st day after challenge, 5 of 6 controls positive had (+) fecal PCRs for up to 126 days post-challenge (P=0.019). Inflammatory colitis developed in 4 of 6 control baboons post-challenge, with invasive E. histolytica trophozoites present in 2 of the 4 on histopathology. There was no evidence of inflammatory colitis or parasite invasion in any of the vaccinated baboons; there was a strong inverse correlation between positive ELISA OD value indicating the presence of intestinal anti-peptide IgA antibodies and baboons having a positive fecal PCR CT value, P<0.001. In conclusion, we developed a novel primate model of E. histolytica intestinal infection and demonstrated that a Gal-lectin-based intranasal synthetic peptide vaccine was highly efficacious in preventing experimental E. histolytica infection and colitis in baboons.
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Christy NCV, Petri WA. Mechanisms of adherence, cytotoxicity and phagocytosis modulate the pathogenesis of Entamoeba histolytica. Future Microbiol 2011; 6:1501-19. [DOI: 10.2217/fmb.11.120] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The unicellular parasite Entamoeba histolytica, the causative agent of the human disease amebiasis, has traditionally been distinguished from its nonpathogenic cousin Entamoeba dispar by its propensity for the ingestion of erythrocytes. This classic feature, along with the parasite’s ability to cause extensive host cell death, are critical mechanisms of pathogenesis during human infection. Recent advances have led to a greater understanding of the molecular components that allow E. histolytica to kill and phagocytose extracellular targets during human infection and include detailed studies of the role of the parasite’s cysteine proteinases and other effectors of cytotoxicity, as well as the mechanisms of ligand recognition, signaling and intracellular trafficking during phagocytosis.
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Affiliation(s)
- Nathaniel CV Christy
- Department of Microbiology, University of Virginia, Charlottesville, Virginia, 22908, USA
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Villalba-Magdaleno JD, Pérez-Ishiwara G, Serrano-Luna J, Tsutsumi V, Shibayama M. In vivo programmed cell death of Entamoeba histolytica trophozoites in a hamster model of amoebic liver abscess. MICROBIOLOGY-SGM 2011; 157:1489-1499. [PMID: 21349978 DOI: 10.1099/mic.0.047183-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Entamoeba histolytica trophozoites can induce host cell apoptosis, which correlates with the virulence of the parasite. This phenomenon has been seen during the resolution of an inflammatory response and the survival of the parasites. Other studies have shown that E. histolytica trophozoites undergo programmed cell death (PCD) in vitro, but how this process occurs within the mammalian host cell remains unclear. Here, we studied the PCD of E. histolytica trophozoites as part of an in vivo event related to the inflammatory reaction and the host-parasite interaction. Morphological study of amoebic liver abscesses showed only a few E. histolytica trophozoites with peroxidase-positive nuclei identified by terminal deoxynucleotidyltransferase enzyme-mediated dUTP nick end labelling (TUNEL). To better understand PCD following the interaction between amoebae and inflammatory cells, we designed a novel in vivo model using a dialysis bag containing E. histolytica trophozoites, which was surgically placed inside the peritoneal cavity of a hamster and left to interact with the host's exudate components. Amoebae collected from bags were then examined by TUNEL assay, fluorescence-activated cell sorting (FACS) and transmission electron microscopy. Nuclear condensation and DNA fragmentation of E. histolytica trophozoites were observed after exposure to peritoneal exudates, which were mainly composed of neutrophils and macrophages. Our results suggest that production of nitric oxide by inflammatory cells could be involved in PCD of trophozoites. In this modified in vivo system, PCD appears to play a prominent role in the host-parasite interaction and parasite cell death.
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Affiliation(s)
- José D'Artagnan Villalba-Magdaleno
- Escuela de Ciencias de la Salud, Universidad del Valle de México, Campus Chapultepec, CP 11850, Mexico.,Departamento de Infectómica y Patogénesis Molecular, CINVESTAV-IPN, CP 07300, Mexico
| | | | | | - Víctor Tsutsumi
- Departamento de Infectómica y Patogénesis Molecular, CINVESTAV-IPN, CP 07300, Mexico
| | - Mineko Shibayama
- Departamento de Infectómica y Patogénesis Molecular, CINVESTAV-IPN, CP 07300, Mexico
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Kissoon-Singh V, Mortimer L, Chadee K. Entamoeba histolytica Cathepsin-Like Enzymes. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2011; 712:62-83. [DOI: 10.1007/978-1-4419-8414-2_5] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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Heron BT, Sateriale A, Teixeira JE, Huston CD. Evidence for a novel Entamoeba histolytica lectin activity that recognises carbohydrates present on ovalbumin. Int J Parasitol 2010; 41:137-44. [PMID: 20807536 DOI: 10.1016/j.ijpara.2010.07.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2010] [Accepted: 07/19/2010] [Indexed: 11/29/2022]
Abstract
Entamoeba histolytica, an intestinal amoeba that causes dysentery and liver abscesses, acquires nutrients by engulfing bacteria in the colonic lumen and phagocytoses apoptotic cells during tissue invasion. In preliminary studies to identify ligands that stimulate amoebic phagocytosis, we used ovalbumin immobilized on latex particles as a potential negative control protein. Surprisingly, ovalbumin strongly stimulated E. histolytica particle uptake. Experiments using highly purified ovalbumin confirmed the specificity of this finding. The mechanism of particle uptake was actin-dependent, and the Entamoeba phagosome marker amoebapore A localised to ovalbumin-bead containing vacuoles. The most well described amoebic receptor is a Gal/GalNAc-specific lectin, but d-galactose had no effect on ovalbumin-stimulated phagocytosis. Ovalbumin has a single N-glycosylation site (Asn(292)) and is modified with oligomannose and hybrid-type oligosaccharides. We used both trifluoromethanesulfonic acid and N-glycanase to deglycosylate ovalbumin and tested the effect. Both methods substantially reduced the stimulatory effect of ovalbumin. Biotinylated ovalbumin bound the surface of fixed E. histolytica trophozoites saturably; furthermore, denatured ovalbumin and native ovalbumin both specifically inhibited ovalbumin-biotin binding, but deglycosylated ovalbumin had no effect. Collectively, these data suggest that E. histolytica has a previously unrecognised surface lectin activity that binds to carbohydrates on ovalbumin and stimulates phagocytosis.
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Affiliation(s)
- Bradley T Heron
- Cell and Molecular Biology Program, University of Vermont College of Medicine, Burlington, VT 05405, USA
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Downregulation of an Entamoeba histolytica rhomboid protease reveals roles in regulating parasite adhesion and phagocytosis. EUKARYOTIC CELL 2010; 9:1283-93. [PMID: 20581296 DOI: 10.1128/ec.00015-10] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Entamoeba histolytica is a deep-branching eukaryotic pathogen. Rhomboid proteases are intramembrane serine proteases, which cleave transmembrane proteins in, or in close proximity to, their transmembrane domain. We have previously shown that E. histolytica contains a single functional rhomboid protease (EhROM1) and has unique substrate specificity. EhROM1 is present on the trophozoite surface and relocalizes to internal vesicles during erythrophagocytosis and to the base of the cap during surface receptor capping. In order to further examine the biological function of EhROM1 we downregulated EhROM1 expression by >95% by utilizing the epigenetic silencing mechanism of the G3 parasite strain. Despite the observation that EhROM1 relocalized to the cap during surface receptor capping, EhROM1 knockdown [ROM(KD)] parasites had no gross changes in cap formation or complement resistance. However, ROM(KD) parasites demonstrated decreased host cell adhesion, a result recapitulated by treatment of wild-type parasites with DCI, a serine protease inhibitor with activity against rhomboid proteases. The reduced adhesion phenotype of ROM(KD) parasites was noted exclusively with healthy cells, and not with apoptotic cells. Additionally, ROM(KD) parasites had decreased phagocytic ability with reduced ingestion of healthy cells, apoptotic cells, and rice starch. Decreased phagocytic ability is thus independent of the reduced adhesion phenotype, since phagocytosis of apoptotic cells was reduced despite normal adhesion levels. The defect in host cell adhesion was not explained by altered expression or localization of the heavy subunit of the Gal/GalNAc surface lectin. These results suggest no significant role of EhROM1 in complement resistance but unexpected roles in parasite adhesion and phagocytosis.
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