scholarly journals Dynamism of PI4-Phosphate during Interactions with Human Erythrocytes in Entamoeba histolytica

2020 ◽  
Vol 8 (7) ◽  
pp. 1050
Author(s):  
Natsuki Watanabe ◽  
Kumiko Nakada-Tsukui ◽  
Tomohiko Maehama ◽  
Tomoyoshi Nozaki
Keyword(s):  
Entamoeba Histolytica ◽  
Cho Cells ◽  
Chinese Hamster ◽  
Protozoan Parasite ◽  
Human Erythrocytes ◽  
Metabolic Labeling ◽  
Intestinal Protozoan ◽  
Vesicular Traffic ◽  
Cellular Events ◽  
Phosphatidylinositol Phosphates

Phosphatidylinositol phosphates (PIPs) are involved in many cellular events as important secondary messengers. In Entamoeba histolytica, a human intestinal protozoan parasite, virulence-associated mechanisms such as cell motility, vesicular traffic, trogo- and phagocytosis are regulated by PIPs. It has been well established that PI3P, PI4P, and PI(3,4,5)P3 play specific roles during amoebic trogo- and phagocytosis. In the present study, we demonstrated the nuclear localization of PI4P in E. histolytica trophozoites in steady state with immunofluorescence imaging and immunoelectron microscopy, using anti-PI4P antibodies and PI4P biosensors [substrate of the Icm/ Dot type IV secretion system (SidM)]. We further showed that the nuclear PI4P decreased after a co-culture with human erythrocytes or Chinese hamster ovary (CHO) cells. However, concomitant changes in the localization and the amount of PI(4,5)P2, which is the expected major metabolized (phosphorylated) product of PI4P, were not observed. This phenomenon was specifically caused by whole or ghost erythrocytes and CHO cells, but not artificial beads. The amount of PIP2 and PIP, biochemically estimated by [32P]-phosphate metabolic labeling and thin layer chromatography, was decreased upon erythrocyte adherence. Altogether, our data indicate for the first time in eukaryotes that erythrocyte attachment leads to the metabolism of nuclear PIPs, and metabolites other than PI(4,5)P2 may be involved in the regulation of downstream cellular events such as cytoskeleton rearrangement or transcriptional regulation.

scholarly journals Autophagy Activated by Peroxiredoxin of Entamoeba histolytica

Cells ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 2462
Author(s):  
Xia Li ◽  
Yuhan Zhang ◽  
Yanqing Zhao ◽  
Ke Qiao ◽  
Meng Feng ◽  
...  
Keyword(s):  
Entamoeba Histolytica ◽  
Protozoan Parasite ◽  
Host Cells ◽  
Functional Domain ◽  
Intestinal Protozoan ◽  
Raw264.7 Macrophages ◽  
Evolutionarily Conserved ◽  
Amoebic Colitis ◽  
Dependent Cell ◽  
Cellular Components

Autophagy, an evolutionarily conserved mechanism to remove redundant or dangerous cellular components, plays an important role in innate immunity and defense against pathogens, which, in turn, can regulate autophagy to establish infection within a host. However, for Entamoeba histolytica, an intestinal protozoan parasite causing human amoebic colitis, the interaction with the host cell autophagy mechanism has not been investigated. In this study, we found that E. histolytica peroxiredoxin (Prx), an antioxidant enzyme critical for parasite survival during the invasion of host tissues, could activate autophagy in macrophages. The formation of autophagosomes in macrophages treated with recombinant Prx of E. histolytica for 24 h was revealed by immunofluorescence and immunoblotting in RAW264.7 cells and in mice. Prx was cytotoxic for RAW264.7 macrophages after 48-h treatment, which was partly attributed to autophagy-dependent cell death. RNA interference experiments revealed that Prx induced autophagy mostly through the toll-like receptor 4 (TLR4)–TIR domain-containing adaptor-inducing interferon (TRIF) pathway. The C-terminal part of Prx comprising 100 amino acids was the key functional domain to activate autophagy. These results indicated that Prx of E. histolytica could induce autophagy and cytotoxic effects in macrophages, revealing a new pathogenic mechanism activated by E. histolytica in host cells.

scholarly journals Near-chromosome level genome assembly reveals ploidy diversity and plasticity in the intestinal protozoan parasite Entamoeba histolytica

BMC Genomics ◽  
2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Tetsuro Kawano-Sugaya ◽  
Shinji Izumiyama ◽  
Yasuaki Yanagawa ◽  
Yumiko Saito-Nakano ◽  
Koji Watanabe ◽  
...  
Keyword(s):  
Entamoeba Histolytica ◽  
Evolutionary Biology ◽  
Regulation Of Gene Expression ◽  
Protozoan Parasite ◽  
Model Organisms ◽  
Intestinal Protozoan ◽  
Disease Symptoms ◽  
Veterinary Importance ◽  
Reference Genomes ◽  
Chromosome Level

Abstract Background Amoebozoa is a eukaryotic supergroup composed of unicellular and multicellular amoebic protozoa (e.g. Acanthamoeba, Dictyostelium, and Entamoeba). They are model organisms for studies in cellular and evolutionary biology and are of medical and veterinary importance. Despite their importance, Amoebozoan genome organization and genetic diversity remain poorly studied due to a lack of high-quality reference genomes. The slime mold Dictyostelium discoideum is the only Amoebozoan species whose genome is available at the chromosome-level. Results Here, we provide a near-chromosome-level assembly of the Entamoeba histolytica genome, the second semi-completed Amoebozoan genome. The availability of this improved genome allowed us to discover inter-strain heterogeneity in ploidy at the near-chromosome or sub-chromosome level among 11 clinical isolates and the reference strain. Furthermore, we observed ploidy-independent regulation of gene expression, contrary to what is observed in other organisms, where RNA levels are affected by ploidy. Conclusions Our findings offer new insights into Entamoeba chromosome organization, ploidy, transcriptional regulation, and inter-strain variation, which will help to further decipher observed spectrums of virulence, disease symptoms, and drug sensitivity of E. histolytica isolates.

scholarly journals Cytopathogenic mechanisms of Entamoeba histolytica.

1980 ◽  
Vol 152 (2) ◽  
pp. 377-390 ◽  
Author(s):  
J I Ravdin ◽  
B Y Croft ◽  
R L Guerrant
Keyword(s):  
Entamoeba Histolytica ◽  
Cho Cells ◽  
Cytochalasin B ◽  
Chinese Hamster ◽  
Cytochalasin D ◽  
Target Cells ◽  
Cho Cell ◽  
The One ◽  
Dose Dependent ◽  
Microtubule Function

Cinemicrography of Entamoeba histolytica destruction of Chinese hamster ovary (CHO) cells shows that ameba cytopathogenicity consists of separate components: a contact-dependent cytolethal effect, and phagocytosis. Cells not in contact with amebae remain intact. Quantitation of ameba destruction of CHO cells by applying the one-hit hypothesis confirms that the cytoethal effect of amebae is contact dependent. Studies with 111Indium oxine-labeled cells provide further evidence of extracellular killing by E. histolytica and indicate that > 94% of the target cells are killed before phagocytosis. When we examined for a cytotoxin release by E. histolytica, we found no effect on CHO cells with filtrates of amebae, and a nonspecific effect of cell rounding and release with sonicates of amebae. The ameba sonicate effect was time-dose dependent, was not cytolethal, was reversible, and was inhibited by alpha II macroglobulin. Cytochalasin B altered ameba motility and morphology, and monolayer experiments confirmed that cytochalasins A, B, or D inhibited CHO cell destruction by E. histolytica. Cytochalasin D also inhibited extracellular killing of CHO cells by amebae in pellets, apparently independent of effects on ameba motility or phagocytosis. Colchicine and vinblastine, alone or in combination with cytochalasin D, did not inhibit E. histolytica cytopathogenicity, which indicates that microtubule function is not required for target cell killing by amebae.

scholarly journals Genome-Wide Analysis of Known and Potential Tetraspanins in Entamoeba histolytica

Genes ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 885 ◽  
Author(s):  
Tomii ◽  
Santos ◽  
Nozaki
Keyword(s):  
Entamoeba Histolytica ◽  
Sequence Similarity ◽  
Protozoan Parasite ◽  
Intercellular Signaling ◽  
Intestinal Protozoan ◽  
Membrane Protein Complex ◽  
Genome Wide Analysis ◽  
Protein Complex Formation ◽  
Genome Wide ◽  
Similarity Searches

Tetraspanins are membrane proteins involved in intra- and/or intercellular signaling, and membrane protein complex formation. In some organisms, their role is associated with virulence and pathogenesis. Here, we investigate known and potential tetraspanins in the human intestinal protozoan parasite Entamoeba histolytica. We conducted sequence similarity searches against the proteome data of E. histolytica and newly identified nine uncharacterized proteins as potential tetraspanins in E. histolytica. We found three subgroups within known and potential tetraspanins, as well as subgroup-associated features in both their amino acid and nucleotide sequences. We also examined the subcellular localization of a few representative tetraspanins that might be potentially related to pathogenicity. The results in this study could be useful resources for further understanding and downstream analyses of tetraspanins in Entamoeba.

scholarly journals The Intestinal Protozoan Parasite Entamoeba histolytica Contains 20 Cysteine Protease Genes, of Which Only a Small Subset Is Expressed during In Vitro Cultivation

2003 ◽  
Vol 2 (3) ◽  
pp. 501-509 ◽  
Author(s):  
Iris Bruchhaus ◽  
Brendan J. Loftus ◽  
Neil Hall ◽  
Egbert Tannich
Keyword(s):  
Entamoeba Histolytica ◽  
Cysteine Protease ◽  
Cathepsin L ◽  
Protozoan Parasite ◽  
Cysteine Proteases ◽  
Small Subset ◽  
In Vitro Cultivation ◽  
Intestinal Protozoan ◽  
Parasite Life Cycle

ABSTRACT Cysteine proteases are known to be important pathogenicity factors of the protozoan parasite Entamoeba histolytica. So far, a total of eight genes coding for cysteine proteases have been identified in E. histolytica, two of which are absent in the closely related nonpathogenic species E. dispar. However, present knowledge is restricted to enzymes expressed during in vitro cultivation of the parasite, which might represent only a subset of the entire repertoire. Taking advantage of the current E. histolytica genome-sequencing efforts, we analyzed databases containing more than 99% of all ameba gene sequences for the presence of cysteine protease genes. A total of 20 full-length genes was identified (including all eight genes previously reported), which show 10 to 86% sequence identity. The various genes obviously originated from two separate ancestors since they form two distinct clades. Despite cathepsin B-like substrate specificities, all of the ameba polypeptides are structurally related to cathepsin L-like enzymes. None of the previously described enzymes but 7 of the 12 newly identified proteins are unique compared to cathepsins of higher eukaryotes in that they are predicted to have transmembrane or glycosylphosphatidylinositol anchor attachment domains. Southern blot analysis revealed that orthologous sequences for all of the newly identified proteases are present in E. dispar. Interestingly, the majority of the various cysteine protease genes are not expressed in E. histolytica or E. dispar trophozoites during in vitro cultivation. Therefore, it is likely that at least some of these enzymes are required for infection of the human host and/or for completion of the parasite life cycle.

scholarly journals Localization of Phosphatidylinositol 4,5-Bisphosphate to Lipid Rafts and Uroids in the Human Protozoan Parasite Entamoeba histolytica

2013 ◽  
Vol 81 (6) ◽  
pp. 2145-2155 ◽  
Author(s):  
Amrita B. Koushik ◽  
Rhonda R. Powell ◽  
Lesly A. Temesvari
Keyword(s):  
Lipid Rafts ◽  
Entamoeba Histolytica ◽  
Protozoan Parasite ◽  
Invasive Infection ◽  
Cellular Functions ◽  
Intestinal Protozoan ◽  
Content Type ◽  
Downstream Effector ◽  
Key Factor ◽  
Actomyosin Cytoskeleton

ABSTRACTEntamoeba histolyticais an intestinal protozoan parasite and is the causative agent of amoebiasis. During invasive infection, highly motile amoebae destroy the colonic epithelium, enter the blood circulation, and disseminate to other organs such as liver, causing liver abscess. Motility is a key factor inE. histolyticapathogenesis, and this process relies on a dynamic actomyosin cytoskeleton. In other systems, phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] is known to regulate a wide variety of cellular functions, including signal transduction, actin remodeling, and cell motility. Little is known about the role of PI(4,5)P2inE. histolyticapathogenicity. In this study, we demonstrate that PI(4,5)P2is localized to cholesterol-rich microdomains, lipid rafts, and the actin-rich fractions of theE. histolyticamembrane. Microscopy revealed that the trailing edge of polarized trophozoites, uroids, are highly enriched in lipid rafts and their constituent lipid, PI(4,5)P2. Polarization and enrichment of uroids and rafts with PI(4,5)P2were enhanced upon treatment ofE. histolyticacells with cholesterol. Exposure to cholesterol also increased intracellular calcium, which is a downstream effector of PI(4,5)P2, with a concomitant increase in motility. Together, our data suggest that inE. histolytica, PI(4,5)P2may signal from lipid rafts and cholesterol may play a role in triggering PI(4,5)P2-mediated signaling to enhance the motility of this pathogen.

scholarly journals Cysteine Protease-Binding Protein Family 6 Mediates the Trafficking of Amylases to Phagosomes in the Enteric Protozoan Entamoeba histolytica

2013 ◽  
Vol 81 (5) ◽  
pp. 1820-1829 ◽  
Author(s):  
Atsushi Furukawa ◽  
Kumiko Nakada-Tsukui ◽  
Tomoyoshi Nozaki
Keyword(s):  
Entamoeba Histolytica ◽  
Cysteine Protease ◽  
Binding Protein ◽  
Proteome Analysis ◽  
Protozoan Parasite ◽  
Cysteine Proteases ◽  
Protein Family ◽  
Intestinal Protozoan ◽  
Α Subunit ◽  
Content Type

ABSTRACTPhagocytosis plays a pivotal role in nutrient acquisition and evasion from the host defense systems inEntamoeba histolytica, the intestinal protozoan parasite that causes amoebiasis. We previously reported thatE. histolyticapossesses a unique class of a hydrolase receptor family, designated the cysteine protease-binding protein family (CPBF), that is involved in trafficking of hydrolases to lysosomes and phagosomes, and we have also reported that CPBF1 and CPBF8 bind to cysteine proteases or β-hexosaminidase α-subunit and lysozymes, respectively. In this study, we showed by immunoprecipitation that CPBF6, one of the most highly expressed CPBF proteins, specifically binds to α-amylase and γ-amylase. We also found that CPBF6 is localized in lysosomes, based on immunofluorescence imaging. Immunoblot and proteome analyses of the isolated phagosomes showed that CPBF6 mediates transport of amylases to phagosomes. We also demonstrated that the carboxyl-terminal cytosolic region of CPBF6 is engaged in the regulation of the trafficking of CPBF6 to phagosomes. Our proteome analysis of phagosomes also revealed new potential phagosomal proteins.

scholarly journals tRNA Gene Sequences Are Required for Transcriptional Silencing in Entamoeba histolytica

2009 ◽  
Vol 9 (2) ◽  
pp. 306-314 ◽  
Author(s):  
Henriette Irmer ◽  
Ina Hennings ◽  
Iris Bruchhaus ◽  
Egbert Tannich
Keyword(s):  
Entamoeba Histolytica ◽  
Trna Gene ◽  
Regulation Of Gene Expression ◽  
Transcriptional Silencing ◽  
Protozoan Parasite ◽  
Upstream Region ◽  
Trna Genes ◽  
Intestinal Protozoan ◽  
Content Type ◽  
Systematic Assessment

ABSTRACT Transcriptional silencing by trans inactivation can contribute to the regulation of gene expression in eukaryotic cells. In the human intestinal protozoan parasite Entamoeba histolytica, trans inactivation of the amoebapore-A gene (AP-A) was recently achieved by episomal transfection of E. histolytica trophozoites with the plasmid psAP1. The mechanism of AP-A trans inactivation is largely unknown, though it was suggested that a partial short interspersed transposable element (SINE) is required. By systematic assessment of various E. histolytica isolates transfected with psAP1 derivates, trans inactivation of AP-A was restricted to the strain HM-1:IMSS (2411) but could not be achieved in other standard laboratory strains. Importantly, sequences of an E. histolytica tRNA array that were located on psAP1 in close proximity to the AP-A upstream region and comprising the glutamic acid (TTC) (E) and tyrosine (GTA) (Y) tRNA genes were indispensable for AP-A silencing. In contrast to the case described in previous reports, SINE was not required for AP-A trans inactivation. AP-A expression could be regained in silenced cells by episomal transfection under the control of a heterologous E. histolytica promoter, opening a way toward future silencing of individual genes of interest in E. histolytica. Our results indicate that tRNA gene-mediated silencing is not restricted to Saccharomyces cerevisiae.

Scanning electron microscopy of erythrophagocytosis by Entamoeba histolytica trophozoites

1992 ◽  
Vol 50 (1) ◽  
pp. 880-881
Author(s):  
Victor Tsutsumi ◽  
Adolfo Martinez-Palomo ◽  
Kyuichi Tanikawa
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Red Blood Cells ◽  
Entamoeba Histolytica ◽  
Causative Agent ◽  
Blood Cells ◽  
Protozoan Parasite ◽  
Complex Phenomenon ◽  
Great Capacity ◽  
Scanning Electron

The protozoan parasite Entamoeba histolytica is the causative agent of amebiasis in man. The trophozoite or motile form is a highly dynamic and pleomorphic cell with a great capacity to destroy tissues. Moreover, the parasite has the singular ability to phagocytize a variety of different live or death cells. Phagocytosis of red blood cells by E. histolytica trophozoites is a complex phenomenon related with amebic pathogenicity and nutrition.

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