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CynthiaVanegas-Villa S, Milena Torres-Cifuentes D, Baylon-Pacheco L, Espíritu-Gordillo P, Durán-Díaz Á, Luis Rosales-Encina J, Omaña-Molina M. External pH Variations Modify Proliferation, Erythrophagocytosis, Cytoskeleton Remodeling, and Cell Morphology of Entamoeba histolytica Trophozoites. Protist 2022; 173:125857. [DOI: 10.1016/j.protis.2022.125857] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Revised: 01/14/2022] [Accepted: 01/17/2022] [Indexed: 10/19/2022]
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da Silva CAV, de Oliveira IMC, Cruz RE, Silva Prado GK, Santos FV, Neves NCV, Gomes MA, Silva Oliveira FM, Caliari MV. South American Entamoeba dispar strains produce amoebic liver abscesses with different pathogenicities and evolutionary kinetics. Acta Trop 2021; 224:106114. [PMID: 34450059 DOI: 10.1016/j.actatropica.2021.106114] [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: 06/22/2021] [Revised: 08/15/2021] [Accepted: 08/16/2021] [Indexed: 11/25/2022]
Abstract
Amoebiasis is a protozoan disease caused by Entamoeba histolytica, and presents a geographic distribution of worldwide amplitude, high incidence, sometimes accompanied by severe clinical manifestations such as amoebic colitis and Amoebic Liver Abscess (ALA), remaining as a public health problem in developing countries. Entamoeba dispar is another species of amoeba that infects approximately 12% of the world's population, and it has previously been classified as noninvasive. However, E. dispar has already been isolated from patients with symptomatic non-dysenteric colitis, as well as its DNA sequences were detected and genotyped in samples from patients with dysenteric colitis, and patients with ALA, suggesting that this species could also be involved in the development of lesions in the large intestine and liver of human beings. In this context, this study aims to evaluate the ability of isolated strains of Entamoeba dispar in South America to cause liver damage, and to better characterize histopathological findings in 3, 8, 12 and 16 days after infection (DAI). Firstly, we assessed whether trophozoites from MCR, ACFN, ICS, ADO and VEJ E. dispar strains, and EGG Entamoeba histolytica strain differed in their in vitro phagocytosis ability, being related to greater ability to phagocyte with greater virulence. Then, we investigate and characterize histopathological changes present in the liver of mice induced by different strains of E. dispar. Our results demonstrated that trophozoites from E. dispar strains are capable of phagocyting human erythrocytes, but in lower amounts than Entamoeba histolytica. In addition, we described and characterized the lesions in different periods after infection by different E. dispar strains, and identified ACFN as the most pathogenic strain, followed by MCR. The large areas of necrosis produced by the ACFN strain as the eighth DAI, which also show high parasitism, led to 100% mortality. On the other hand, the ICS, ADO and VEJ strains did not produce mortality, and this was correlated with the presence of well-developed chronic granulomatous inflammation, necrosis absorption throughout the infection, and regeneration of the liver parenchyma. The greater pathogenicity of the ACFN strain strongly suggests that this strain could be producing higher levels of virulence factors. As the experimental infection, the heterogeneity of biological behavior of different Entamoeba dispar strains could be involved in the development of undiagnosed human clinical conditions.
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Drug repositioning: antiprotozoal activity of terfenadine against Entamoeba histolytica trophozoites. Parasitol Res 2021; 121:303-309. [PMID: 34741218 DOI: 10.1007/s00436-021-07354-x] [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: 06/04/2021] [Accepted: 10/16/2021] [Indexed: 10/19/2022]
Abstract
The infection caused by Entamoeba histolytica is still a serious public health problem, especially in developing countries. The goal of this study was to evaluate the effect of terfenadine against Entamoeba histolytica. The trophozoites were exposed to 1, 2, 3, and 4 μM of terfenadine, for 24 and 48 h. Consequently, the viability of cells was determined by trypan blue exclusion test. The effect of terfenadine on adhesion of Entamoeba histolytica was evaluated in Caco-2 cells. In addition, the effect of terfenadine on the erythrophagocytic capacity of the parasite was investigated. The results show that terfenadine affects the growth and cell viability in a time- and dose-dependent manner. The higher inhibitory effects were observed with 4 µM at 48 h; 91.6% of growth inhibition and only 22.5% of trophozoites were viable. Additionally, we demonstrate that terfenadine is highly selective for the parasite and has low toxicity on Caco-2 cells. Furthermore, adhesion to Caco-2 cells and erythrophagocytic capacity were significantly inhibited. These findings demonstrate that terfenadine exerts significant effects on the virulence of Entamoeba histolytica. This is the first study demonstrating the amoebicidal activity of terfenadine and the results suggest it may be effective in the treatment of amoebiasis.
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Wanderley JLM, DaMatta RA, Barcinski MA. Apoptotic mimicry as a strategy for the establishment of parasitic infections: parasite- and host-derived phosphatidylserine as key molecule. Cell Commun Signal 2020; 18:10. [PMID: 31941500 PMCID: PMC6964003 DOI: 10.1186/s12964-019-0482-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 11/11/2019] [Indexed: 12/14/2022] Open
Abstract
The establishment of parasitic infection is dependent on the development of efficient strategies to evade the host defense mechanisms. Phosphatidylserine (PS) molecules are pivotal for apoptotic cell recognition and clearance by professional phagocytes. Moreover, PS receptors are able to trigger anti-inflammatory and immunosuppressive responses by phagocytes, either by coupled enzymes or through the induction of regulatory cytokine secretion. These PS-dependent events are exploited by parasites in a mechanism called apoptotic mimicry. Generally, apoptotic mimicry refers to the effects of PS recognition for the initiation and maintenance of pathogenic infections. However, in this context, PS molecules can be recognized on the surface of the infectious agent or in the surface of apoptotic host debris, leading to the respective denomination of classical and non-classical apoptotic mimicry. In this review, we discuss the role of PS in the pathogenesis of several human infections caused by protozoan parasites. Video Abstract
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Affiliation(s)
- João Luiz Mendes Wanderley
- Laboratório de Imunoparasitologia, Campus UFRJ Macaé, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
| | - Renato Augusto DaMatta
- Laboratório de Biologia Celular e Tecidual, Centro de Biociências e Biotecnologia, Universidade Estadual Norte-Fluminense, Campos dos Goytacazes, RJ, Brazil
| | - Marcello André Barcinski
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
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Constantino‐Jonapa LA, Hernández‐Ramírez VI, Osorio‐Trujillo C, Talamás‐Rohana P. Eh
Rab21 mobilization during erythrophagocytosis in
Entamoeba histolytica. Microsc Res Tech 2018; 81:1024-1035. [DOI: 10.1002/jemt.23069] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Revised: 05/03/2018] [Accepted: 05/25/2018] [Indexed: 01/22/2023]
Affiliation(s)
- Luis A. Constantino‐Jonapa
- Departamento de Infectómica y Patogénesis MolecularCentro de Investigación y de Estudios Avanzados del I.P.N., Avenida Instituto Politécnico Nacional No. 2508Col. San Pedro Zacatenco, Delegación Gustavo A. Madero, CDMXCP 07360, Mexico
| | - Verónica Ivonne Hernández‐Ramírez
- Departamento de Infectómica y Patogénesis MolecularCentro de Investigación y de Estudios Avanzados del I.P.N., Avenida Instituto Politécnico Nacional No. 2508Col. San Pedro Zacatenco, Delegación Gustavo A. Madero, CDMXCP 07360, Mexico
| | - Carlos Osorio‐Trujillo
- Departamento de Infectómica y Patogénesis MolecularCentro de Investigación y de Estudios Avanzados del I.P.N., Avenida Instituto Politécnico Nacional No. 2508Col. San Pedro Zacatenco, Delegación Gustavo A. Madero, CDMXCP 07360, Mexico
| | - Patricia Talamás‐Rohana
- Departamento de Infectómica y Patogénesis MolecularCentro de Investigación y de Estudios Avanzados del I.P.N., Avenida Instituto Politécnico Nacional No. 2508Col. San Pedro Zacatenco, Delegación Gustavo A. Madero, CDMXCP 07360, Mexico
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6
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Sierra-López F, Baylón-Pacheco L, Espíritu-Gordillo P, Lagunes-Guillén A, Chávez-Munguía B, Rosales-Encina JL. Influence of Micropatterned Grill Lines on Entamoeba histolytica Trophozoites Morphology and Migration. Front Cell Infect Microbiol 2018; 8:295. [PMID: 30197879 PMCID: PMC6117912 DOI: 10.3389/fcimb.2018.00295] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 08/02/2018] [Indexed: 12/28/2022] Open
Abstract
Entamoeba histolytica, the causal agent of human amoebiasis, has two morphologically different phases: a resistant cyst and a trophozoite responsible for the invasion of the host tissues such as the colonic mucosa and the intestinal epithelium. During in vitro migration, trophozoites usually produce protuberances such as pseudopods and rarely filopodia, structures that have been observed in the interaction of trophozoites with human colonic epithelial tissue. To study the different membrane projections produced by the trophozoites, including pseudopods, filopodia, uropods, blebs, and others, we designed an induction system using erythrocyte extract or fibronectin (FN) in micropatterned grill lines (each micro-line containing multiple micro-portions of FN or erythrocyte extract) on which the trophozoites were placed in culture for migration assays. Using light, confocal, and scanning electron microscopy, we established that E. histolytica trophozoites frequently produce short and long filopodia, large retractile uropods in the rear, pseudopods, blebs, and others structures, also showing continuous migration periods. The present study provides a simple migration method to induce trophozoites to generate abundant membrane protrusion structures that are rarely obtained in normal or induced cultures, such as long filopodia; this method will allow a–better understanding of the interactions of trophozoites with FN and cell debris. E. histolytica trophozoites motility plays an important role in invasive amoebiasis. It has been proposed that both physical forces and chemical signals are involved in the trophozoite motility and migration. However, the in vivo molecules that drive the chemotactic migration remain to be determined. We propose the present assay to study host molecules that guide chemotactic behavior because the method is highly reproducible, and a live image of cell movement and migration can be quantified.
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Affiliation(s)
- Francisco Sierra-López
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
| | - Lidia Baylón-Pacheco
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
| | - Patricia Espíritu-Gordillo
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
| | - Anel Lagunes-Guillén
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
| | - Bibiana Chávez-Munguía
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
| | - José L Rosales-Encina
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
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7
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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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8
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Martin WF, Tielens AGM, Mentel M, Garg SG, Gould SB. The Physiology of Phagocytosis in the Context of Mitochondrial Origin. Microbiol Mol Biol Rev 2017; 81:e00008-17. [PMID: 28615286 PMCID: PMC5584316 DOI: 10.1128/mmbr.00008-17] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
How mitochondria came to reside within the cytosol of their host has been debated for 50 years. Though current data indicate that the last eukaryote common ancestor possessed mitochondria and was a complex cell, whether mitochondria or complexity came first in eukaryotic evolution is still discussed. In autogenous models (complexity first), the origin of phagocytosis poses the limiting step at eukaryote origin, with mitochondria coming late as an undigested growth substrate. In symbiosis-based models (mitochondria first), the host was an archaeon, and the origin of mitochondria was the limiting step at eukaryote origin, with mitochondria providing bacterial genes, ATP synthesis on internalized bioenergetic membranes, and mitochondrion-derived vesicles as the seed of the eukaryote endomembrane system. Metagenomic studies are uncovering new host-related archaeal lineages that are reported as complex or phagocytosing, although images of such cells are lacking. Here we review the physiology and components of phagocytosis in eukaryotes, critically inspecting the concept of a phagotrophic host. From ATP supply and demand, a mitochondrion-lacking phagotrophic archaeal fermenter would have to ingest about 34 times its body weight in prokaryotic prey to obtain enough ATP to support one cell division. It would lack chemiosmotic ATP synthesis at the plasma membrane, because phagocytosis and chemiosmosis in the same membrane are incompatible. It would have lived from amino acid fermentations, because prokaryotes are mainly protein. Its ATP yield would have been impaired relative to typical archaeal amino acid fermentations, which involve chemiosmosis. In contrast, phagocytosis would have had great physiological benefit for a mitochondrion-bearing cell.
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Affiliation(s)
- William F Martin
- Institute for Molecular Evolution, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Aloysius G M Tielens
- Department of Biochemistry and Cell Biology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
- Department of Medical Microbiology and Infectious Diseases, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Marek Mentel
- Department of Biochemistry, Faculty of Natural Sciences, Comenius University in Bratislava, Bratislava, Slovakia
| | - Sriram G Garg
- Institute for Molecular Evolution, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Sven B Gould
- Institute for Molecular Evolution, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
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9
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Hanadate Y, Saito-Nakano Y, Nakada-Tsukui K, Nozaki T. Endoplasmic reticulum-resident Rab8A GTPase is involved in phagocytosis in the protozoan parasite Entamoeba histolytica. Cell Microbiol 2016; 18:1358-73. [PMID: 26807810 PMCID: PMC5071775 DOI: 10.1111/cmi.12570] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Revised: 12/31/2015] [Accepted: 01/19/2016] [Indexed: 12/20/2022]
Abstract
Phagocytosis is indispensable for the pathogenesis of the intestinal protozoan parasite Entamoeba histolytica. Here, we showed that in E. histolytica Rab8A, which is generally involved in trafficking from the trans‐Golgi network to the plasma membrane in other organisms but was previously identified in phagosomes of the amoeba in the proteomic analysis, primarily resides in the endoplasmic reticulum (ER) and participates in phagocytosis. We demonstrated that down‐regulation of EhRab8A by small antisense RNA‐mediated transcriptional gene silencing remarkably reduced adherence and phagocytosis of erythrocytes, bacteria and carboxylated latex beads. Surface biotinylation followed by SDS‐PAGE analysis revealed that the surface expression of several proteins presumably involved in target recognition was reduced in the EhRab8A gene‐silenced strain. Further, overexpression of wild‐type EhRab8A augmented phagocytosis, whereas expression of the dominant‐negative form of EhRab8A resulted in reduced phagocytosis. These results indicated that EhRab8A regulates transport of surface receptor(s) for the prey from the ER to the plasma membrane. To our knowledge, this is the first report that the ER‐resident Rab GTPase is involved in phagocytosis through the regulation of trafficking of a surface receptor, supporting a premise of direct involvement of the ER in phagocytosis.
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Affiliation(s)
- Yuki Hanadate
- Department of Parasitology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo, 162-8640, Japan.,Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8572, Japan
| | - Yumiko Saito-Nakano
- Department of Parasitology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo, 162-8640, Japan
| | - Kumiko Nakada-Tsukui
- Department of Parasitology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo, 162-8640, Japan
| | - Tomoyoshi Nozaki
- Department of Parasitology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo, 162-8640, Japan. .,Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8572, Japan.
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10
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Knockdown of Five Genes Encoding Uncharacterized Proteins Inhibits Entamoeba histolytica Phagocytosis of Dead Host Cells. Infect Immun 2016; 84:1045-1053. [PMID: 26810036 DOI: 10.1128/iai.01325-15] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Accepted: 01/15/2016] [Indexed: 12/17/2022] Open
Abstract
Entamoeba histolytica is the protozoan parasite that causes invasive amebiasis, which is endemic to many developing countries and characterized by dysentery and liver abscesses. The virulence of E. histolytica correlates with the degree of host cell engulfment, or phagocytosis, and E. histolytica phagocytosis alters amebic gene expression in a feed-forward manner that results in an increased phagocytic ability. Here, we used a streamlined RNA interference screen to silence the expression of 15 genes whose expression was upregulated in phagocytic E. histolytica trophozoites to determine whether these genes actually function in the phagocytic process. When five of these genes were silenced, amebic strains with significant decreases in the ability to phagocytose apoptotic host cells were produced. Phagocytosis of live host cells, however, was largely unchanged, and the defects were surprisingly specific for phagocytosis. Two of the five encoded proteins, which we named E. histolytica ILWEQ (EhILWEQ) and E. histolytica BAR (EhBAR), were chosen for localization via SNAP tag labeling and localized to the site of partially formed phagosomes. Therefore, both EhILWEQ and EhBAR appear to contribute to E. histolytica virulence through their function in phagocytosis, and the large proportion (5/15 [33%]) of gene-silenced strains with a reduced ability to phagocytose host cells validates the previously published microarray data set demonstrating feed-forward control of E. histolytica phagocytosis. Finally, although only limited conclusions can be drawn from studies using the virulence-deficient G3 Entamoeba strain, the relative specificity of the defects induced for phagocytosis of apoptotic cells but not healthy cells suggests that cell killing may play a rate-limiting role in the process of Entamoeba histolytica host cell engulfment.
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11
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Talamás-Lara D, Talamás-Rohana P, Fragoso-Soriano RJ, Espinosa-Cantellano M, Chávez-Munguía B, González-Robles A, Martínez-Palomo A. Cell-matrix interactions of Entamoeba histolytica and E. dispar. A comparative study by electron-, atomic force- and confocal microscopy. Exp Cell Res 2015; 337:226-33. [DOI: 10.1016/j.yexcr.2015.07.030] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2015] [Revised: 07/26/2015] [Accepted: 07/28/2015] [Indexed: 12/15/2022]
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12
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Ralston KS. Chew on this: amoebic trogocytosis and host cell killing by Entamoeba histolytica. Trends Parasitol 2015; 31:442-52. [PMID: 26070402 DOI: 10.1016/j.pt.2015.05.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Revised: 05/04/2015] [Accepted: 05/05/2015] [Indexed: 01/23/2023]
Abstract
Entamoeba histolytica was named 'histolytica' (from histo-, 'tissue'; lytic-, 'dissolving') for its ability to destroy host tissues. Direct killing of host cells by the amoebae is likely to be the driving factor that underlies tissue destruction, but the mechanism was unclear. We recently showed that, after attaching to host cells, amoebae bite off and ingest distinct host cell fragments, and that this contributes to cell killing. We review this process, termed 'amoebic trogocytosis' (trogo-, 'nibble'), and how this process interplays with phagocytosis, or whole cell ingestion, in this organism. 'Nibbling' processes have been described in other microbes and in multicellular organisms. The discovery of amoebic trogocytosis in E. histolytica may also shed light on an evolutionarily conserved process for intercellular exchange.
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Affiliation(s)
- Katherine S Ralston
- Department of Microbiology and Molecular Genetics, University of California, Davis, CA 95616, USA.
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13
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Affiliation(s)
- Vern B. Carruthers
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
- * E-mail:
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14
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Talamás-Lara D, Chávez-Munguía B, González-Robles A, Talamás-Rohana P, Salazar-Villatoro L, Durán-Díaz Á, Martínez-Palomo A. Erythrophagocytosis in Entamoeba histolytica and Entamoeba dispar: a comparative study. BIOMED RESEARCH INTERNATIONAL 2014; 2014:626259. [PMID: 25003123 PMCID: PMC4066688 DOI: 10.1155/2014/626259] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Revised: 05/09/2014] [Accepted: 05/09/2014] [Indexed: 01/08/2023]
Abstract
Entamoeba histolytica is the causative agent of human intestinal and liver amebiasis. The extraordinary phagocytic activity of E. histolytica trophozoites has been accepted as one of the virulence mechanisms responsible for their invasive capacity. The recognition of the noninvasive Entamoeba dispar as a different species has raised the question as to whether the lack of pathogenic potential of this ameba correlates with a limited phagocytic capacity. We have therefore compared the process of erythrophagocytosis in both species by means of light and video microscopy, hemoglobin measurement, and the estimation of reactive oxygen species (ROS). In the present study, we confirmed that E. dispar has lower erythrophagocytic capacity. We also observed by video microscopy a new event of erythrocyte opsonization-like in both species, being more characteristic in E. histolytica. Moreover, E. dispar showed a lower capacity to produce ROS compared with the invasive species and also showed a large population of amoebae that did not engulf any erythrocyte over time. Our results demonstrate that E. histolytica has a higher phagocytic capacity than E. dispar, including a higher rate of production of ROS in the course of ingesting red blood cells.
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Affiliation(s)
- Daniel Talamás-Lara
- Department of Infectomics and Molecular Pathogenesis, Center for Research and Advanced Studies, IPN, Avenida Instituto Politécnico Nacional No. 2508, Colonia San Pedro Zacatenco, Delegación Gustavo A. Madero, 07360 Mexico City, DF, Mexico
| | - Bibiana Chávez-Munguía
- Department of Infectomics and Molecular Pathogenesis, Center for Research and Advanced Studies, IPN, Avenida Instituto Politécnico Nacional No. 2508, Colonia San Pedro Zacatenco, Delegación Gustavo A. Madero, 07360 Mexico City, DF, Mexico
| | - Arturo González-Robles
- Department of Infectomics and Molecular Pathogenesis, Center for Research and Advanced Studies, IPN, Avenida Instituto Politécnico Nacional No. 2508, Colonia San Pedro Zacatenco, Delegación Gustavo A. Madero, 07360 Mexico City, DF, Mexico
| | - Patricia Talamás-Rohana
- Department of Infectomics and Molecular Pathogenesis, Center for Research and Advanced Studies, IPN, Avenida Instituto Politécnico Nacional No. 2508, Colonia San Pedro Zacatenco, Delegación Gustavo A. Madero, 07360 Mexico City, DF, Mexico
| | - Lizbeth Salazar-Villatoro
- Department of Infectomics and Molecular Pathogenesis, Center for Research and Advanced Studies, IPN, Avenida Instituto Politécnico Nacional No. 2508, Colonia San Pedro Zacatenco, Delegación Gustavo A. Madero, 07360 Mexico City, DF, Mexico
| | - Ángel Durán-Díaz
- Faculty of Superior Studies Iztacala, Biology, UNAM, Los Reyes Iztacala, 54090 Tlalnepantla, MEX, Mexico
| | - Adolfo Martínez-Palomo
- Department of Infectomics and Molecular Pathogenesis, Center for Research and Advanced Studies, IPN, Avenida Instituto Politécnico Nacional No. 2508, Colonia San Pedro Zacatenco, Delegación Gustavo A. Madero, 07360 Mexico City, DF, Mexico
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15
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Nowak B, Valdenegro-Vega V, Crosbie P, Bridle A. Immunity to amoeba. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2014; 43:257-267. [PMID: 23921258 DOI: 10.1016/j.dci.2013.07.021] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2013] [Revised: 07/02/2013] [Accepted: 07/28/2013] [Indexed: 06/02/2023]
Abstract
Amoebic infections in fish are most likely underestimated and sometimes overlooked due to the challenges associated with their diagnosis. Amoebic diseases reported in fish affect either gills or internal organs or may be systemic. Host response ranges from hyperplastic response in gill infections to inflammation (including granuloma formation) in internal organs. This review focuses on the immune response of Atlantic salmon to Neoparamoeba perurans, the causative agent of Amoebic Gill Disease (AGD).
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Affiliation(s)
- Barbara Nowak
- NCMCRS, AMC, University of Tasmania, Launceston, Tasmania, Australia.
| | | | - Philip Crosbie
- NCMCRS, AMC, University of Tasmania, Launceston, Tasmania, Australia
| | - Andrew Bridle
- NCMCRS, AMC, University of Tasmania, Launceston, Tasmania, Australia
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Mancilla-Herrera I, Méndez-Tenorio A, Wong-Baeza I, Jiménez-Uribe AP, Alcántara-Hernández M, Ocadiz-Ruiz R, Moreno-Eutimio MA, Arriaga-Pizano LA, López-Macías C, González-y-Merchand J, Isibasi A. A Toll/IL-1R/resistance domain-containing thioredoxin regulates phagocytosis in Entamoeba histolytica. Parasit Vectors 2012; 5:224. [PMID: 23043976 PMCID: PMC3481431 DOI: 10.1186/1756-3305-5-224] [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] [Received: 02/22/2012] [Accepted: 09/22/2012] [Indexed: 11/22/2022] Open
Abstract
Background Entamoeba histolytica is a protozoan parasite that infects humans and causes amebiasis affecting developing countries. Phagocytosis of epithelial cells, erythrocytes, leucocytes, and commensal microbiota bacteria is a major pathogenic mechanism used by this parasite. A Toll/IL-1R/Resistance (TIR) domain-containing protein is required in phagocytosis in the social ameba Dictyostelium discoideum, an ameba closely related to Entamoeba histolytica in phylogeny. In insects and vertebrates, TIR domain-containing proteins regulate phagocytic and cell activation. Therefore, we investigated whether E. histolytica expresses TIR domain-containing molecules that may be involved in the phagocytosis of erythrocytes and bacteria. Methods Using in silico analysis we explored in Entamoeba histolytica databases for TIR domain containing sequences. After silencing TIR domain containing sequences in trophozoites by siRNA we evaluated phagocytosis of erythrocytes and bacteria. Results We identified an E. histolytica thioredoxin containing a TIR-like domain. The secondary and tertiary structure of this sequence exhibited structural similarity to TIR domain family. Thioredoxin transcripts silenced in E. histolytica trophozoites decreased erythrocytes and E. coli phagocytosis. Conclusion TIR domain-containing thioredoxin of E. histolytica could be an important element in erythrocytes and bacteria phagocytosis.
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Affiliation(s)
- Ismael Mancilla-Herrera
- Medical Research Unit on Immunochemistry, Specialties Hospital, National Medical Centre Siglo XXI, Mexican Social Security Institute, Mexico City, Mexico
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17
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Abstract
The parasitic protozoan Entamoeba histolytica is aptly named for its capacity to destroy host tissue. When E. histolytica trophozoites invade the lamina propria of a host colon, extracellular matrices are degraded while host cells are killed and phagocytosed. The ability of E. histolytica to phagocytose host cells correlates with virulence in vivo. In order to better understand the mechanism of phagocytosis, we used an E. histolytica Affymetrix microarray chip to measure the total gene expression of phagocytic and nonphagocytic subpopulations. Using paramagnetic beads coated with a known host ligand that stimulates phagocytosis, phagocytic and nonphagocytic amoebae from a single culture were purified. Microarray analysis of the subpopulations identified 121 genes with >2-fold higher expression in phagocytic than in nonphagocytic amoebae. Functional annotation identified genes encoding proteins involved in actin binding and cytoskeletal organization as highly enriched gene clusters. Post hoc analyses of selected genes showed that the gene expression profile identified in the microarray experiment did not exist prior to cell sorting but rather was stimulated through phagocytosis. Further, these expression profiles correlated with an increase in phagocytic ability, as E. histolytica cultures exposed to an initial stimulus of phagocytosis showed increased phagocytic ability upon a second stimulus. To our knowledge, this is the first description of such feed-forward regulation of gene expression and phagocytic ability in a phagocyte.
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18
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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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19
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Marie CS, Verkerke HP, Paul SN, Mackey AJ, Petri WA. Leptin protects host cells from Entamoeba histolytica cytotoxicity by a STAT3-dependent mechanism. Infect Immun 2012; 80:1934-43. [PMID: 22331430 PMCID: PMC3347425 DOI: 10.1128/iai.06140-11] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2011] [Accepted: 01/29/2012] [Indexed: 11/20/2022] Open
Abstract
The adipocytokine leptin links nutritional status to immune function. Leptin signaling protects from amebiasis, but the molecular mechanism is not understood. We developed an in vitro model of ameba-host cell interaction to test the hypothesis that leptin prevents ameba-induced apoptosis in host epithelial cells. We demonstrated that activation of mammalian leptin signaling increased cellular resistance to amebic cytotoxicity, including caspase-3 activation. Exogenous expression of the leptin receptor conferred resistance in susceptible cells, and leptin stimulation enhanced protection. A series of leptin receptor signaling mutants showed that resistance to amebic cytotoxicity was dependent on activation of STAT3 but not the Src homology-2 domain-containing tyrosine phosphatase (SHP-2) or STAT5. A common polymorphism in the leptin receptor (Q223R) that increases susceptibility to amebiasis in humans and mice was found to increase susceptibility to amebic cytotoxicity in single cells. The Q223R polymorphism also decreased leptin-dependent STAT3 activation by 21% relative to that of the wild-type (WT) receptor (P = 0.035), consistent with a central role of STAT3 signaling in protection. A subset of genes uniquely regulated by STAT3 in response to leptin was identified. Most notable were the TRIB1 and suppressor of cytokine signaling 3 (SOCS3) genes, which have opposing roles in the regulation of apoptosis. Overall apoptotic genes were highly enriched in this gene set (P < 1E-05), supporting the hypothesis that leptin regulation of host apoptotic genes via STAT3 is responsible for protection. This is the first demonstration of a mammalian signaling pathway that restricts amebic pathogenesis and represents an important advance in our mechanistic understanding of how leptin links nutrition and susceptibility to infection.
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Affiliation(s)
- Chelsea S Marie
- Biology Department, Drew University, Madison, New Jersey, USA.
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20
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Exposure to host ligands correlates with colocalization of Gal/GalNAc lectin subunits in lipid rafts and phosphatidylinositol (4,5)-bisphosphate signaling in Entamoeba histolytica. EUKARYOTIC CELL 2012; 11:743-51. [PMID: 22505337 DOI: 10.1128/ec.00054-12] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Entamoeba histolytica is an intestinal parasite that causes dysentery and liver abscess. Parasite cell surface receptors, such as the Gal/GalNAc lectin, facilitate attachment to host cells and extracellular matrix. The Gal/GalNAc lectin binds to galactose or N-acetylgalactosamine residues on host components and is composed of heavy (Hgl), intermediate (Igl), and light (Lgl) subunits. Although Igl is constitutively localized to lipid rafts (cholesterol-rich membrane domains), Hgl and Lgl transiently associate with this compartment in a cholesterol-dependent fashion. In this study, trophozoites were exposed to biologically relevant ligands to determine if ligand binding influences the submembrane distribution of the subunits. Exposure to human red blood cells (hRBCs) or collagen, which are bona fide Gal/GalNAc lectin ligands, was correlated with enrichment of Hgl and Lgl in rafts. This enrichment was abrogated in the presence of galactose, suggesting that direct lectin-ligand interactions are necessary to influence subunit location. Using a cell line that is able to attach to, but not phagocytose, hRBCs, it was shown that physical attachment to ligands was not sufficient to induce the enrichment of lectin subunits in rafts. Additionally, the mutant had lower levels of phosphatidylinositol (4,5)-bisphosphate (PIP(2)); PIP(2) loading restored the ability of this mutant to respond to ligands with enrichment of subunits in rafts. Finally, intracellular calcium levels increased upon attachment to collagen; this increase was essential for the enrichment of lectin subunits in rafts. Together, these data provide evidence that ligand-induced enrichment of lectin subunits in rafts may be the first step in a signaling pathway that involves both PIP(2) and calcium signaling.
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21
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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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22
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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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23
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Localisation to lipid rafts correlates with increased function of the Gal/GalNAc lectin in the human protozoan parasite, Entamoeba histolytica. Int J Parasitol 2011; 41:1409-19. [PMID: 22085647 DOI: 10.1016/j.ijpara.2011.10.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2011] [Revised: 09/23/2011] [Accepted: 10/06/2011] [Indexed: 11/24/2022]
Abstract
Entamoeba histolytica is the causative agent of dysentery and liver abscess and is prevalent in developing countries. Adhesion to the host is critical to infection and is mediated by amoebic surface receptors. One such receptor, the Gal/GalNAc lectin, binds to galactose or N-acetylgalactosamine residues on host components and consists of heavy (Hgl), light (Lgl) and intermediate (Igl) subunits. The mechanism by which the lectin assembles into a functional complex is not known. The parasite also relies on cholesterol-rich domains (lipid rafts) for adhesion. Therefore, it is conceivable that rafts regulate the assembly or function of the lectin. To test this, amoebae were loaded with cholesterol and lipid rafts were purified and characterised. Western blotting showed that cholesterol loading resulted in co-compartmentalisation of all three subunits in rafts. This co-compartmentalisation was accompanied by an increase in the ability of the amoebae to bind to host cells in a galactose-specific manner, suggesting that there is a correlation between location and function of the Gal/GalNAc lectin. Cholesterol loading did not increase the surface levels of the lectin subunits. Therefore, the cholesterol-induced increase in adhesion was not the result of externalisation of an internal pool of subunits. A mutant cell line that modestly responded to cholesterol with a slight increase in adhesion exhibited only a slight enrichment of Hgl and Lgl in rafts. This supports the connection between location and function of the Gal/GalNAc lectin. Actin can also influence the interaction of proteins with rafts. Therefore, the sub-membrane distribution of the lectin subunits was also assessed after treatment with an actin depolymerising agent, cytochalasin D. Cytochalasin D-treatment had no effect on the submembrane distribution of the subunits, suggesting that actin does not prevent the association of lectin subunits with rafts in this system. Together, these data provide insight into the molecular mechanisms regulating the location and function of this adhesin.
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24
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Jang YS, Song KJ, Kim JY, Lee YA, Kim KA, Lee SK, Shin MH. Calpains are involved in Entamoeba histolytica-induced death of HT-29 colonic epithelial cells. THE KOREAN JOURNAL OF PARASITOLOGY 2011; 49:177-80. [PMID: 21738275 PMCID: PMC3121076 DOI: 10.3347/kjp.2011.49.2.177] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/02/2011] [Revised: 04/05/2011] [Accepted: 04/10/2011] [Indexed: 12/16/2022]
Abstract
Entamoeba histolytica is an enteric tissue-invading protozoan parasite that can cause amebic colitis and liver abscess in humans. E. histolytica has the capability to kill colon epithelial cells in vitro; however, information regarding the role of calpain in colon cell death induced by ameba is limited. In this study, we investigated whether calpains are involved in the E. histolytica-induced cell death of HT-29 colonic epithelial cells. When HT-29 cells were co-incubated with E. histolytica, the propidium iodide stained dead cells markedly increased compared to that in HT-29 cells incubated with medium alone. This pro-death effect induced by ameba was effectively blocked by pretreatment of HT-29 cells with the calpain inhibitor, calpeptin. Moreover, knockdown of m- and µ-calpain by siRNA significantly reduced E. histolytica-induced HT-29 cell death. These results suggest that m- and µ-calpain may be involved in colon epithelial cell death induced by E. histolytica.
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Affiliation(s)
- Yun Soo Jang
- Department of Environmental Medical Biology, Yonsei University College of Medicine, Seoul 120-752, Korea
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25
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A Sequential Model of Host Cell Killing and Phagocytosis by Entamoeba histolytica. J Parasitol Res 2011; 2011:926706. [PMID: 21331284 PMCID: PMC3038552 DOI: 10.1155/2011/926706] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2010] [Accepted: 12/19/2010] [Indexed: 11/17/2022] Open
Abstract
The protozoan parasite Entamoeba histolytica is responsible for invasive intestinal and extraintestinal amebiasis. The virulence of Entamoeba histolytica is strongly correlated with the parasite's capacity to effectively kill and phagocytose host cells. The process by which host cells are killed and phagocytosed follows a sequential model of adherence, cell killing, initiation of phagocytosis, and engulfment. This paper presents recent advances in the cytolytic and phagocytic processes of Entamoeba histolytica in context of the sequential model.
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26
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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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27
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Franca-Bot A, Franca J, Franca E, Honorio-Fr A, O. Busatti H, Gomes M. Relationship Between Oxidative Stress Production and Virulence Capacity of Entamoeba Strains. ACTA ACUST UNITED AC 2010. [DOI: 10.3923/jp.2010.139.147] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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28
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Becker SM, Cho KN, Guo X, Fendig K, Oosman MN, Whitehead R, Cohn SM, Houpt ER. Epithelial cell apoptosis facilitates Entamoeba histolytica infection in the gut. THE AMERICAN JOURNAL OF PATHOLOGY 2010; 176:1316-22. [PMID: 20093500 DOI: 10.2353/ajpath.2010.090740] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Entamoeba histolytica is the protozoan parasite that causes amebic colitis. The parasite triggers apoptosis on contact with host cells; however, the biological significance of this event during intestinal infection is unclear. We examined the role of apoptosis in a mouse model of intestinal amebiasis. Histopathology revealed that abundant epithelial cell apoptosis occurred in the vicinity of amoeba in histological specimens. Epithelial cell apoptosis occurred rapidly on co-culture with amoeba in vitro as measured by annexin positivity, DNA degradation, and mitochondrial dysfunction. Administration of the pan caspase inhibitor ZVAD decreased the rate and severity of amebic infection in CBA mice by all measures (cecal culture positivity, parasite enzyme-linked immunosorbent assay, and histological scores). Similarly, caspase 3 knockout mice on the resistant C57BL/6 background exhibited even lower cecal parasite antigen burden and culture positive rates than wild type mice. The permissive effect of apoptosis on infection could be tracked to the epithelium, in that transgenic mice that overexpressed Bcl-2 in epithelial cells were more resistant to infection as measured by cecal parasite enzyme-linked immunosorbent assay and histological scores. We concluded that epithelial cell apoptosis in the intestine facilitates amebic infection in this mouse model. The parasite's strategy for inducing apoptosis may point to key virulence factors, and therapeutic maneuvers to diminish epithelial apoptosis may be useful in amebic colitis.
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Affiliation(s)
- Stephen M Becker
- Division of Infectious Diseases and International Health, Department of Medicine, University of Virginia, Charlottesville, VA 22908, USA
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29
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The role of lipopeptidophosphoglycan in the immune response to Entamoeba histolytica. J Biomed Biotechnol 2010; 2010:254521. [PMID: 20145703 PMCID: PMC2817369 DOI: 10.1155/2010/254521] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2009] [Accepted: 10/12/2009] [Indexed: 12/14/2022] Open
Abstract
The sensing of Pathogen Associated Molecular Patterns (PAMPs) by innate immune receptors, such as Toll-like receptors (TLRs), is the first step in the inflammatory response to pathogens. Entamoeba histolytica, the etiological agent of amebiasis, has a surface molecule with the characteristics of a PAMP. This molecule, which was termed lipopeptidophosphoglycan (LPPG), is recognized through TLR2 and TLR4 and leads to the release of cytokines from human monocytes, macrophages, and dendritic cells; LPPG-activated dendritic cells have increased expression of costimulatory molecules. LPPG activates NKT cells in a CD1d-dependent manner, and this interaction limits amebic liver abscess development. LPPG also induces antibody production, and anti-LPPG antibodies prevent disease development in animal models of amebiasis. Because LPPG is recognized by both the innate and the adaptive immune system (it is a “Pamptigen”), it may be a good candidate to develop a vaccine against E. histolytica infection and an effective adjuvant.
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30
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Buss SN, Hamano S, Vidrich A, Evans C, Zhang Y, Crasta OR, Sobral BW, Gilchrist CA, Petri WA. Members of the Entamoeba histolytica transmembrane kinase family play non-redundant roles in growth and phagocytosis. Int J Parasitol 2010; 40:833-43. [PMID: 20083116 DOI: 10.1016/j.ijpara.2009.12.007] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2009] [Revised: 12/15/2009] [Accepted: 12/17/2009] [Indexed: 10/20/2022]
Abstract
Entamoeba histolytica contains a large and novel family of transmembrane kinases (TMKs). The expression patterns of the E. histolytica TMKs in individual trophozoites and the roles of the TMKs for sensing and responding to extracellular cues were incompletely characterised. Here we provide evidence that single cells express multiple TMKs and that TMK39 and TMK54 likely serve non-redundant cellular functions. Laser-capture microdissection was used in conjunction with microarray analysis to demonstrate that single trophozoites express more than one TMK gene. Anti-peptide antibodies were raised against unique regions in the extracellular domains of TMK39, TMK54 and PaTMK, and TMK expression was analysed at the protein level. Flow cytometric assays revealed that populations of trophozoites homogeneously expressed TMK39, TMK54 and PaTMK, while confocal microscopy identified different patterns of cell surface expression for TMK39 and TMK54. The functions of TMK39 and TMK54 were probed by the inducible expression of dominant-negative mutants. While TMK39 co-localised with ingested beads and expression of truncated TMK39 interfered with trophozoite phagocytosis of apoptotic lymphocytes, expression of a truncated TMK54 inhibited growth of amoebae and altered the surface expression of the heavy subunit of the E. histolytica Gal/GalNAc lectin. Overall, our data indicates that multiple members of the novel E. histolytica TMK family are utilised for non-redundant functions by the parasite.
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Affiliation(s)
- Sarah N Buss
- Department of Microbiology, University of Virginia, Charlottesville, VA 22908-1340, USA.
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31
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Olivos-García A, Saavedra E, Ramos-Martínez E, Nequiz M, Pérez-Tamayo R. Molecular nature of virulence in Entamoeba histolytica. INFECTION GENETICS AND EVOLUTION 2009; 9:1033-7. [PMID: 19376272 DOI: 10.1016/j.meegid.2009.04.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2008] [Revised: 03/30/2009] [Accepted: 04/03/2009] [Indexed: 01/07/2023]
Abstract
For many years virulence of pathogenic Entamoeba histolytica has been attributed to the capacity of the parasite to destroy tissues through the expression and/or secretion of various molecules. Such view is supported mainly by in vitro experimentation, whereas data obtained by using animal models of the disease have clearly demonstrated that the host's inflammatory response is primarily responsible for tissue damage. This review analyzes the content and/or activity of some of the presumed toxic amebic molecules present in amebic strains with different degrees of virulence compared to various parasite in vitro functions that are supposed to correlate with in vivo virulence. The analysis suggests that amebic virulence is primarily determined by the parasite's capacity to adapt and survive the aerobic conditions present in animal tissues. This initial episode in the host-parasite relationship is an absolute requirement for the further development of tissue lesions, which result from the concerted action of many molecules derived from both, the host and the parasite.
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Affiliation(s)
- Alfonso Olivos-García
- Departamento de Medicina Experimental Facultad de Medicina, Universidad Nacional Autónoma de México, México DF, Mexico.
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32
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Overexpression of a mutant form of EhRabA, a unique Rab GTPase of Entamoeba histolytica, alters endoplasmic reticulum morphology and localization of the Gal/GalNAc adherence lectin. EUKARYOTIC CELL 2009; 8:1014-26. [PMID: 19377040 DOI: 10.1128/ec.00030-09] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Entamoeba histolytica is a protozoan parasite that causes amoebic dysentery and liver abscess. Vesicle trafficking events, such as phagocytosis and delivery of plasma membrane proteins, have been implicated in pathogenicity. Rab GTPases are proteins whose primary function is to regulate vesicle trafficking; therefore, understanding the function of Rabs in this organism may provide insight into virulence. E. histolytica possesses a number of unique Rabs that exhibit limited homology to host Rabs. In this study we examined the function of one such Rab, EhRabA, by characterizing a mutant overexpressing a constitutively GTP-bound version of the protein. Overexpression of mutant EhRabA resulted in decreased adhesion to and phagocytosis of human red blood cells and in the appearance of large tubular organelles that could be stained with endoplasmic reticulum (ER)-specific but not Golgi complex-specific antibodies. Consistent with the adhesion defect, two subunits of a cell surface adhesin, the galactose/N-acetylgalactosamine lectin, were mislocalized to the novel organelle. A cysteine protease, EhCP2, was also localized to the ER-like compartment in the mutant; however, the localization of two additional cell surface proteins, Igl and SREHP, remained unchanged in the mutant. The phenotype of the mutant could be recapitulated by treatment with brefeldin A, a cellular toxin that disrupts ER-to-Golgi apparatus vesicle traffic. This suggests that EhRabA influences vesicle trafficking pathways that are also sensitive to brefeldin A. Together, the data indicate that EhRabA directly or indirectly influences the morphology of secretory organelles and regulates trafficking of a subset of secretory proteins in E. histolytica.
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33
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Teixeira JE, Heron BT, Huston CD. C1q- and collectin-dependent phagocytosis of apoptotic host cells by the intestinal protozoan Entamoeba histolytica. J Infect Dis 2008; 198:1062-70. [PMID: 18702607 DOI: 10.1086/591628] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
BACKGROUND Entamoeba histolytica, the cause of invasive amebiasis, phagocytoses apoptotic host cells during tissue invasion. In mammals, collectin family members (e.g., mannose-binding lectin [MBL]) and the structurally related protein C1q bind to apoptotic cells and stimulate macrophage phagocytosis via a conserved collagenous tail domain. The collectins also bind to bacteria, the usual source of nutrients for E. histolytica. METHODS To test the possibility that the collectins are ligands that stimulate E. histolytica phagocytosis, we used a flow cytometry-based assay for amebic phagocytosis, a method for making single-ligand particles to delineate a given ligand's ability to initiate phagocytosis, and purified human C1q, MBL, and collagenous collectin tails. RESULTS Apoptotic lymphocytes opsonized with serum or human C1q were phagocytosed more efficiently than control cells, an effect that was dependent on ligand density. C1q and the collectins alone were adequate to trigger amebic phagocytosis, because single-ligand particles coated with C1q, MBL, or purified collectin tails were phagocytosed more efficiently than control particles. Furthermore, C1q, MBL, and the tail domain of C1q were all chemoattractants for E. histolytica. CONCLUSIONS C1q and MBL can serve as opsonins on apoptotic cells that stimulate E. histolytica phagocytosis, an effect mediated at least in part by the collagenous collectin tail domain.
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Affiliation(s)
- Jose Eduardo Teixeira
- Department of Medicine, University of Vermont College of Medicine, Burlington, VT 05405, USA
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Vicente JB, Ehrenkaufer GM, Saraiva LM, Teixeira M, Singh U. Entamoeba histolytica modulates a complex repertoire of novel genes in response to oxidative and nitrosative stresses: implications for amebic pathogenesis. Cell Microbiol 2008; 11:51-69. [PMID: 18778413 DOI: 10.1111/j.1462-5822.2008.01236.x] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Upon host infection, the protozoan parasite Entamoeba histolytica is confronted with reactive oxygen and nitrogen species and must survive these stresses in order to cause invasive disease. We analysed the parasite's response to oxidative and nitrosative stresses, probing the transcriptional changes of trophozoites of a pathogenic strain after a 60 min exposure to H2O2 (1 mM) or a NO donor (dipropylenetriamine-NONOate, 200 microM), using whole-genome DNA microarrays. Genes encoding reactive oxygen and nitrogen species detoxification enzymes had high transcriptional levels under basal conditions and upon exposure to both stresses. On a whole-genome level, there was significant modulation of gene expression by H2O2 (286 genes regulated) and dipropylenetriamine-NONOate (1036 genes regulated) with a significant overlap of genes modulated under both conditions (164 genes). A number of transcriptionally regulated genes were in signalling/regulatory and repair/metabolic pathways. However, the majority of genes with altered transcription encode unknown proteins, suggesting as yet unraveled response pathways in E. histolytica. Trophozoites of a non-pathogenic E. histolytica strain had a significantly muted transcriptional response to H2O2 compared with the pathogenic strain, hinting that differential response to oxidative stress may be one factor that contributes to the pathogenic potential of E. histolytica.
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Affiliation(s)
- João B Vicente
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305-5107, USA
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Boettner DR, Huston CD, Linford AS, Buss SN, Houpt E, Sherman NE, Petri WA. Entamoeba histolytica phagocytosis of human erythrocytes involves PATMK, a member of the transmembrane kinase family. PLoS Pathog 2008; 4:e8. [PMID: 18208324 PMCID: PMC2211552 DOI: 10.1371/journal.ppat.0040008] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2007] [Accepted: 12/10/2007] [Indexed: 11/19/2022] Open
Abstract
Entamoeba histolytica is the cause of amebic colitis and liver abscess. This parasite induces apoptosis in host cells and utilizes exposed ligands such as phosphatidylserine to ingest the apoptotic corpses and invade deeper into host tissue. The purpose of this work was to identify amebic proteins involved in the recognition and ingestion of dead cells. A member of the transmembrane kinase family, phagosome-associated TMK96 (PATMK), was identified in a proteomic screen for early phagosomal proteins. Anti-peptide affinity-purified antibody produced against PATMK demonstrated that it was a type I integral membrane protein that was expressed on the trophozoite surface, and that co-localized with human erythrocytes at the site of contact. The role of PATMK in erythrophagocytosis in vitro was demonstrated by: (i) incubation of ameba with anti-PATMK antibodies; (ii) PATMK mRNA knock-down using a novel shRNA expression system; and (iii) expression of a carboxy-truncation of PATMK (PATMKΔ932). Expression of the carboxy-truncation of PATMKΔ932 also caused a specific reduction in the ability of E. histolytica to establish infection in the intestinal model of amebiasis, however these amebae retained the ability to cause hepatic abscesses when directly injected in the liver. In conclusion, PATMK was identified as a member of the TMK family that participates in erythrophagocytosis and is uniquely required for intestinal infection. There is a highly ordered process by which the parasite Entamoeba histolytica interacts with human cells. Adherence via a parasite lectin is followed in seconds by killing, with only the corpse and not a living cell ingested by the ameba. This process is so central to pathogenesis that clinicians use the presence of ingested erythrocytes to identify E. histolytica and distinguish it from harmless commensal amebae of the gut. We hypothesized that identification of molecules involved in the ingestion of the corpse might provide insight into how amebae cause colitis. We identified a member of the transmembrane kinase family as an early component of the phagosome. Inhibition of this kinase blocked red cell ingestion and prevented amebae from colonizing and invading the gut. There was no impact on dominant-negative parasites to cause liver abscess, suggesting the pathogenesis program differs between anatomic sites. Future studies of the transmembrane kinanse in erythrophagocytosis may provide insight into how amebae colonize and invade the gut, with the ultimate goal of preventing disease.
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Affiliation(s)
- Douglas R Boettner
- Department of Microbiology, University of Virginia, Charlottesville, Virginia, United States of America
| | - Christopher D Huston
- Department of Medicine, University of Vermont, Burlington, Vermont, United States of America
- Department of Microbiology, University of Vermont, Burlington, Vermont, United States of America
| | - Alicia S Linford
- Department of Microbiology, University of Virginia, Charlottesville, Virginia, United States of America
| | - Sarah N Buss
- Department of Microbiology, University of Virginia, Charlottesville, Virginia, United States of America
| | - Eric Houpt
- Department of Medicine, University of Virginia, Charlottesville, Virginia, United States of America
| | - Nicholas E Sherman
- Department of Microbiology, University of Virginia, Charlottesville, Virginia, United States of America
| | - William A Petri
- Department of Microbiology, University of Virginia, Charlottesville, Virginia, United States of America
- Department of Medicine, University of Virginia, Charlottesville, Virginia, United States of America
- Department of Pathology, University of Virginia, Charlottesville, Virginia, United States of America
- * To whom correspondence should be addressed. E-mail:
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Teixeira JE, Huston CD. Participation of the serine-rich Entamoeba histolytica protein in amebic phagocytosis of apoptotic host cells. Infect Immun 2008; 76:959-66. [PMID: 18086807 PMCID: PMC2258814 DOI: 10.1128/iai.01455-07] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2007] [Revised: 11/28/2007] [Accepted: 12/07/2007] [Indexed: 11/20/2022] Open
Abstract
Entamoeba histolytica is an intestinal ameba that causes dysentery and liver abscesses. Cytotoxicity and phagocytosis of host cells characterize invasive E. histolytica infection. Prior to phagocytosis of host cells, E. histolytica induces apoptotic host cell death, using a mechanism that requires contact via an amebic galactose-specific lectin. However, lectin inhibition only partially blocks phagocytosis of already dead cells, implicating at least one additional receptor in phagocytosis. To identify receptors for engulfment of apoptotic cells, monoclonal antibodies against E. histolytica membrane antigens were screened for inhibition of phagocytosis. Of 43 antibodies screened, one blocked lectin-independent uptake of apoptotic cells, with >90% inhibition at a dose of 20 microg/ml (P < 0.0003 versus control). The same antibody also inhibited adherence to apoptotic lymphocytes and, to a lesser extent, adherence to and killing of viable lymphocytes. The antigen recognized by the inhibitory antibody was purified by affinity chromatography and identified by liquid chromatography-mass spectrometry as the serine-rich E. histolytica protein (SREHP). Consistent with this, the inhibitory antibody bound to recombinant SREHP present in bacterial lysates on immunoblots. The SREHP is an abundant immunogenic surface protein of unclear function. The results of this unbiased antibody screen strongly implicate the SREHP as a participant in E. histolytica phagocytosis and suggest that it may play an important role in adherence to apoptotic cells.
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Affiliation(s)
- Jose E Teixeira
- Department of Medicine, University of Vermont College of Medicine, Burlington, VT 05405, USA
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Bercu TE, Petri WA, Behm JW. Amebic colitis: new insights into pathogenesis and treatment. Curr Gastroenterol Rep 2008; 9:429-33. [PMID: 17991346 DOI: 10.1007/s11894-007-0054-8] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Amebiasis, caused by the protozoan parasite Entamoeba histolytica, affects more than 50 million people worldwide, with over 100,000 deaths annually. The majority of cases are asymptomatic; however, significant morbidity and mortality are associated with illness in the remaining 10% of cases. Recent advances in the understanding of the mechanism of infection by E. histolytica, the role of the innate immune system, and the role of genetic disposition to infection will allow the development of novel detection and treatment methods. The disease mechanisms, clinical findings, therapeutic strategies, and important developments regarding amebiasis are discussed here.
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Affiliation(s)
- Tracy E Bercu
- Division of Infectious Diseases and International Health, University of Virginia Health System, P.O. Box 801340, Charlottesville, VA 22908, USA.
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Hemozoin: oil versus water. Parasitol Int 2007; 57:89-96. [PMID: 18373972 DOI: 10.1016/j.parint.2007.09.009] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2007] [Revised: 09/26/2007] [Accepted: 09/28/2007] [Indexed: 11/23/2022]
Abstract
Because the quinolines inhibit heme crystallization within the malaria parasite much work has focused on mechanism of formation and inhibition of hemozoin. Here we review the recent evidence for heme crystallization within lipids in diverse parasites and the new implications of a lipid site of crystallization for drug targeting. Within leukocytes hemozoin can generate toxic radical lipid metabolites, which may alter immune function or reduce deformability of uninfected erythrocytes.
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Sim S, Park SJ, Yong TS, Im KI, Shin MH. Involvement of β2-integrin in ROS-mediated neutrophil apoptosis induced by Entamoeba histolytica. Microbes Infect 2007; 9:1368-75. [PMID: 17900957 DOI: 10.1016/j.micinf.2007.06.013] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2007] [Revised: 06/22/2007] [Accepted: 06/25/2007] [Indexed: 12/13/2022]
Abstract
Cellular adhesion through beta 2-integrin (CD18) is an important step in signal transduction leading to apoptosis of human neutrophils, and NADPH oxidase-derived reactive oxygen species (ROS) are essential for neutrophil apoptosis induced by Entamoeba histolytica. Therefore, we investigated the role of beta 2-integrin-mediated signals in ROS-dependent neutrophil apoptosis induced by E. histolytica. Entamoeba-induced apoptosis was inhibited by pre-incubation of cells with mAb to CD18, but not CD29, suggesting that beta )-integrin plays an important role in this response. Moreover, Entamoeba-induced ROS generation in neutrophils was inhibited by mAbs against CD18 or CD11b, but not by mAbs against CD11a, CD11c, or CD29. A combination of d-galactose plus anti-CD18 mAb had a larger inhibitory effect than d-galactose alone on Entamoeba-induced apoptosis and ROS generation. Furthermore, Entamoeba-induced apoptosis and ROS generation were inhibited by pre-treatment of cells with an inhibitor of phosphatidylinositol-3-kinase (PI-3-kinase). These results indicate that beta 2-integrin and PI-3-kinase are crucial signaling molecules in ROS-dependent apoptosis of neutrophils induced by E. histolytica.
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Affiliation(s)
- Seobo Sim
- Department of Environmental and Tropical Medicine, Konkuk University School of Medicine, Chungju 380-701, Republic of Korea
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Schaumburg F, Hippe D, Vutova P, Lüder CGK. Pro- and anti-apoptotic activities of protozoan parasites. Parasitology 2006; 132 Suppl:S69-85. [PMID: 17018167 DOI: 10.1017/s0031182006000874] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
During infection, programmed cell death, i.e. apoptosis, is an important effector mechanism of innate and adaptive host responses to parasites. In addition, it fulfils essential functions in regulating host immunity and tissue homeostasis. Not surprisingly, however, adaptation of parasitic protozoa to their hosts also involves modulation or even exploitation of cell death in order to facilitate parasite survival in a hostile environment. During recent years, considerable progress has been made in our understanding of apoptosis during parasitic infections and there is now convincing evidence that apoptosis and its modulation by protozoan parasites has a major impact on the parasite-host interaction and on the pathogenesis of disease. This review updates our current knowledge on the diverse functions apoptosis may fulfil during infections with diverse protozoan parasites including apicomplexans, kinetoplastids and amoebae. Furthermore, we also summarize common mechanistic themes of the pro- and anti-apoptotic activities of protozoan parasites. The diverse and complex effects which parasitic protozoa exert on apoptotic cell death within the host highlight fascinating interactions of parasites and their hosts. Importantly, they also stress the importance of further investigations before the modulation of host cell apoptosis can be exploited to combat parasitic infections.
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Affiliation(s)
- F Schaumburg
- Institute for Medical Microbiology, Georg-August-University, Kreuzbergring 57, 37075 Göttingen, Germany
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Kammanadiminti SJ, Chadee K. Suppression of NF-κB Activation by Entamoeba histolytica in Intestinal Epithelial Cells Is Mediated by Heat Shock Protein 27. J Biol Chem 2006; 281:26112-20. [PMID: 16840786 DOI: 10.1074/jbc.m601988200] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Little is known about the pathogenesis of Entamoeba histolytica and how epithelial cells respond to the parasite. Herein, we characterized the interactions between E. histolytica and colonic epithelial cells and the role macrophages play in modulating epithelial cell responses. The human colonic epithelial cell lines Caco-2 and T84 were grown either as monoculture or co-cultured in transwell plates with differentiated human THP-1 macrophages for 24 h before stimulation with soluble amebic proteins (SAP). In naive epithelial cells, prolonged stimulation with SAP reduced the levels of heat shock protein (Hsp) 27 and 72. However in THP-1 conditioned intestinal epithelial cells SAP enhanced Hsp27 and Hsp72, which was dependent on the activation of ERK MAP kinase. Hsp synthesis induced by SAP conferred protection against oxidative and apoptotic injuries. Treatment with SAP inhibited NF-kappaB activation induced by interleukin-1beta; specifically, the NF-kappaB-DNA binding, nuclear translocation of p65 subunit, and phosphorylation of IkappaB-alpha were reduced. Gene silencing by small interfering RNA confirmed the role of Hsp27 in suppressing NF-kappaB activation at IkappaB kinase (IKK) level. By co-immunoprecipitation studies, we found that Hsp27 interacts with IKK-alpha and IKK-beta, and this association was increased in SAP-treated conditioned epithelial cells. Overexpression of wild type Hsp27 amplified the effects of SAP, whereas a phosphorylation-deficient mutant of Hsp27 abrogated SAP-induced NF-kappaB inhibition. In conditioned epithelial cells, Hsp27 was phosphorylated at serine 15 after prolonged exposure to SAP. This mechanism may explain the absence of colonic inflammation seen in the majority of individuals infected with E. histolytica.
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Affiliation(s)
- Srinivas J Kammanadiminti
- Department of Microbiology and Infectious Diseases, University of Calgary, Calgary, Alberta T2N 4N1, Canada
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Welter BH, Powell RR, Laughlin RC, McGugan GC, Bonner M, King A, Temesvari LA. Entamoeba histolytica: Comparison of the role of receptors and filamentous actin among various endocytic processes. Exp Parasitol 2006; 113:91-9. [PMID: 16458294 DOI: 10.1016/j.exppara.2005.12.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2005] [Revised: 12/14/2005] [Accepted: 12/20/2005] [Indexed: 11/21/2022]
Abstract
Entamoeba histolytica is the causative agent of amoebic dysentery. Uptake of iron is critical for E. histolytica growth and iron-bound human transferrin (holo-transferrin) has been shown to serve as an iron source in vitro. Although a transferrin-binding protein has been identified in E. histolytica, the mechanism by which this iron source is taken up by this pathogen is not well understood. To gain insight into this process, the uptake of fluorescent-dextran, -holo-transferrin, and human red blood cells (hRBCs) was compared. Both dextran and transferrin were taken up in an apparent receptor-independent fashion as compared to hRBCs, which were taken up in a receptor-mediated fashion. Interestingly, the uptake of FITC-dextran and FITC-holo-transferrin differentially relied on an intact actin cytoskeleton suggesting that their internalization routes may be regulated independently.
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Affiliation(s)
- B H Welter
- Department of Biological Sciences, Clemson University, SC 29634, USA
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Huston CD, Miller-Sims VC, Teixeira JE. Identification and characterization of EhABC A1, an Entamoeba histolytica Group A ABC transporter with similarity to Ced-7. Mol Biochem Parasitol 2006; 146:272-6. [PMID: 16442643 DOI: 10.1016/j.molbiopara.2005.12.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2005] [Revised: 12/21/2005] [Accepted: 12/24/2005] [Indexed: 11/24/2022]
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Marion S, Guillén N. Genomic and proteomic approaches highlight phagocytosis of living and apoptotic human cells by the parasite Entamoeba histolytica. Int J Parasitol 2005; 36:131-9. [PMID: 16386742 DOI: 10.1016/j.ijpara.2005.10.007] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2005] [Revised: 10/17/2005] [Accepted: 10/24/2005] [Indexed: 11/15/2022]
Abstract
Phagocytosis plays a major role during the invasive process of the human intestine by the pathogenic amoeba E. histolytica. This parasite is the etiologic agent causing amoebic dysentery, a worldwide disease causing 50 million of clinical cases leading to about 100,000 deaths annually. The invasive process is characterized by a local acute inflammation and the destruction of the intestinal tissue at the invasion site. The recent sequencing of the E. histolytica genome has opened the way to large-scale approaches to study parasite virulence such as processes involved in human cell phagocytosis. In particular, two different studies have recently described the phagosome proteome, providing new insights into the process of phagocytosis by this pathogenic protozoan. It has been previously described that E. histolytica induces apoptosis and phagocytosis of the human target cells. Induction of apoptosis by the trophozoites is thought to be involved in the close regulation of the inflammatory response occurring during infection. Little is known about the molecular mechanisms responsible for induction of apoptosis or in the recognition of apoptotic cells by E. histolytica. In this review, we comment on the recent data we obtained after isolation of the early phagosomes and the identification of its associated proteins. We focus on the surface molecules potentially involved in human cell recognition. In particular, we propose several parasite molecules, potentially involved in the induction of apoptosis and/or the phagocytosis of human apoptotic cells.
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Affiliation(s)
- Sabrina Marion
- Unité de Biologie Cellulaire du Parasitisme, INSERM U389, Institut Pasteur: 28 rue du Dr Roux 75724 Paris Cedex 15, France
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