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Yanagawa Y, Singh U. Diversity and Plasticity of Virulent Characteristics of Entamoeba histolytica. Trop Med Infect Dis 2023; 8:tropicalmed8050255. [PMID: 37235303 DOI: 10.3390/tropicalmed8050255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 04/27/2023] [Accepted: 04/27/2023] [Indexed: 05/28/2023] Open
Abstract
The complexity of clinical syndromes of amebiasis, caused by the parasite Entamoeba histolytica, stems from the intricate interplay between the host immune system, the virulence of the invading parasite, and the surrounding environment. Although there is still a relative paucity of information about the precise relationship between virulence factors and the pathogenesis of Entamoeba histolytica, by accumulating data from clinical and basic research, researchers have identified essential pathogenic factors that play a critical role in the pathogenesis of amebiasis, providing important insights into disease development through animal models. Moreover, the parasite's genetic variability has been associated with differences in virulence and disease outcomes, making it important to fully understand the epidemiology and pathogenesis of amebiasis. Deciphering the true mechanism of disease progression in humans caused by this parasite is made more difficult through its ability to demonstrate both genomic and pathological plasticity. The objective of this article is to underscore the heterogeneous nature of disease states and the malleable virulence characteristics in experimental models, while also identifying persistent scientific issues that need to be addressed.
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Affiliation(s)
- Yasuaki Yanagawa
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Upinder Singh
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA
- Division of Infectious Diseases, Department of Internal Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
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Shrivastav MT, Malik Z, Somlata. Revisiting Drug Development Against the Neglected Tropical Disease, Amebiasis. Front Cell Infect Microbiol 2021; 10:628257. [PMID: 33718258 PMCID: PMC7943716 DOI: 10.3389/fcimb.2020.628257] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Accepted: 12/30/2020] [Indexed: 11/15/2022] Open
Abstract
Amebiasis is a neglected tropical disease which is caused by the protozoan parasite Entamoeba histolytica. This disease is one of the leading causes of diarrhea globally, affecting largely impoverished residents in developing countries. Amebiasis also remains one of the top causes of gastrointestinal diseases in returning international travellers. Despite having many side effects, metronidazole remains the drug of choice as an amebicidal tissue-active agent. However, emergence of metronidazole resistance in pathogens having similar anaerobic metabolism and also in laboratory strains of E. histolytica has necessitated the identification and development of new drug targets and therapeutic strategies against the parasite. Recent research in the field of amebiasis has led to a better understanding of the parasite’s metabolic and cellular pathways and hence has been useful in identifying new drug targets. On the other hand, new molecules effective against amebiasis have been mined by modifying available compounds, thereby increasing their potency and efficacy and also by repurposing existing approved drugs. This review aims at compiling and examining up to date information on promising drug targets and drug molecules for the treatment of amebiasis.
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Affiliation(s)
- Manish T Shrivastav
- Multidisciplinary Centre for Advanced Research and Studies, Jamia Millia Islamia, New Delhi, India
| | - Zainab Malik
- Multidisciplinary Centre for Advanced Research and Studies, Jamia Millia Islamia, New Delhi, India
| | - Somlata
- Multidisciplinary Centre for Advanced Research and Studies, Jamia Millia Islamia, New Delhi, India
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Martínez-Pérez Y, Nequiz-Avendaño M, García-Torres I, Gudiño-Zayas ME, López-Velázquez G, Enríquez-Flores S, Mendoza E, Saavedra E, Pérez-Tamayo R, León-Avila G, Olivos-García A. Rabeprazole inhibits several functions of Entamoeba histolytica related with its virulence. Parasitol Res 2020; 119:3491-3502. [PMID: 32886229 DOI: 10.1007/s00436-020-06868-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 08/26/2020] [Indexed: 11/24/2022]
Abstract
Amoebiasis is a human parasitic disease caused by Entamoeba histolytica. The parasite can invade the large intestine and other organs such as liver; resistance to the host tissue oxygen is a condition for parasite invasion and survival. Thioredoxin reductase of E. histolytica (EhTrxR) is a critical enzyme mainly involved in maintaining reduced the redox system and detoxifying the intracellular oxygen; therefore, it is necessary for E. histolytica survival under both aerobic in vitro and in vivo conditions. In the present work, it is reported that rabeprazole (Rb), a drug widely used to treat heartburn, was able to inhibit the EhTrxR recombinant enzyme. Moreover, Rb affected amoebic proliferation and several functions required for parasite virulence such as cytotoxicity, oxygen reduction to hydrogen peroxide, erythrophagocytosis, proteolysis, and oxygen and complement resistances. In addition, amoebic pre-incubation with sublethal Rb concentration (600 μM) promoted amoebic death during early liver infection in hamsters. Despite the high Rb concentration used to inhibit amoebic virulence, the wide E. histolytica pathogenic-related functions affected by Rb strongly suggest that its molecular structure can be used as scaffold to design new antiamoebic compounds with lower IC50 values.
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Affiliation(s)
- Yoalli Martínez-Pérez
- Departamento de Zoología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Carpio y Plan de Ayala S/N. Col. Casco de Santo Tomás, Ciudad de México, 11340, México. .,Unidad de Investigación en Medicina Experimental, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad de México, 04510, México.
| | - Mario Nequiz-Avendaño
- Unidad de Investigación en Medicina Experimental, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad de México, 04510, México
| | - Itzhel García-Torres
- Grupo de Investigación en Biomoléculas y Salud Infantil, Laboratorio de EIMyT, Instituto Nacional de Pediatría, Ciudad de México, 04530, México
| | - Marco E Gudiño-Zayas
- Unidad de Investigación en Medicina Experimental, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad de México, 04510, México
| | - Gabriel López-Velázquez
- Grupo de Investigación en Biomoléculas y Salud Infantil, Laboratorio de EIMyT, Instituto Nacional de Pediatría, Ciudad de México, 04530, México
| | - Sergio Enríquez-Flores
- Grupo de Investigación en Biomoléculas y Salud Infantil, Laboratorio de EIMyT, Instituto Nacional de Pediatría, Ciudad de México, 04530, México
| | - Edith Mendoza
- Unidad de Investigación en Medicina Experimental, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad de México, 04510, México
| | - Emma Saavedra
- Departamento de Bioquímica, Instituto Nacional de Cardiología Ignacio Chávez, Ciudad de México, 14080, México
| | - Ruy Pérez-Tamayo
- Unidad de Investigación en Medicina Experimental, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad de México, 04510, México
| | - Gloria León-Avila
- Departamento de Zoología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Carpio y Plan de Ayala S/N. Col. Casco de Santo Tomás, Ciudad de México, 11340, México
| | - Alfonso Olivos-García
- Unidad de Investigación en Medicina Experimental, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad de México, 04510, México
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Nagaraja S, Ankri S. Target identification and intervention strategies against amebiasis. Drug Resist Updat 2019; 44:1-14. [PMID: 31112766 DOI: 10.1016/j.drup.2019.04.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2018] [Revised: 04/27/2019] [Accepted: 04/30/2019] [Indexed: 12/22/2022]
Abstract
Entamoeba histolytica is the etiological agent of amebiasis, which is an endemic parasitic disease in developing countries and is the cause of approximately 70,000 deaths annually. E. histolytica trophozoites usually reside in the colon as a non-pathogenic commensal in most infected individuals (90% of infected individuals are asymptomatic). For unknown reasons, these trophozoites can become virulent and invasive, cause amebic dysentery, and migrate to the liver where they cause hepatocellular damage. Amebiasis is usually treated either by amebicides which are classified as (a) luminal and are active against the luminal forms of the parasite, (b) tissue and are effective against those parasites that have invaded tissues, and (c) mixed and are effective against the luminal forms of the parasite and those forms which invaded the host's tissues. Of the amebicides, the luminal amebicide, metronidazole (MTZ), is the most widely used drug to treat amebiasis. Although well tolerated, concerns about its adverse effects and the possible emergence of MTZ-resistant strains of E. histolytica have led to the development of new therapeutic strategies against amebiasis. These strategies include improving the potency of existing amebicides, discovering new uses for approved drugs (repurposing of existing drugs), drug rediscovery, vaccination, drug targeting of essential E. histolytica components, and the use of probiotics and bioactive natural products. This review examines each of these strategies in the light of the current knowledge on the gut microbiota of patients with amebiasis.
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Affiliation(s)
- Shruti Nagaraja
- Department of Molecular Microbiology, Ruth and Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
| | - Serge Ankri
- Department of Molecular Microbiology, Ruth and Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel.
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Fernando DD, Reynolds SL, Zakrzewski M, Mofiz E, Papenfuss AT, Holt D, Fischer K. Phylogenetic relationships, stage-specific expression and localisation of a unique family of inactive cysteine proteases in Sarcoptes scabiei. Parasit Vectors 2018; 11:301. [PMID: 29769145 PMCID: PMC5956821 DOI: 10.1186/s13071-018-2862-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 04/23/2018] [Indexed: 11/17/2022] Open
Abstract
Background Scabies is worldwide one of the most common, yet neglected, parasitic skin infections, affecting a wide range of mammals including humans. Limited treatment options and evidence of emerging mite resistance against the currently used drugs drive our research to explore new therapeutic candidates. Previously, we discovered a multicopy family of genes encoding cysteine proteases with their catalytic sites inactivated by mutation (SMIPP-Cs). This protein family is unique in parasitic scabies mites and is absent in related non-burrowing mites. We postulated that the SMIPP-Cs have evolved as an adaptation to the parasitic lifestyle of the scabies mite. To formulate testable hypotheses for their functions and to propose possible strategies for translational research we investigated whether the SMIPP-Cs are common to all scabies mite varieties and where within the mite body as well as when throughout the parasitic life-cycle they are expressed. Results SMIPP-C sequences from human, pig and dog mites were analysed bioinformatically and the phylogenetic relationships between the SMIPP-C multi-copy gene families of human, pig and dog mites were established. Results suggest that amplification of the SMIPP-C genes occurred in a common ancestor and individual genes evolved independently in the different mite varieties. Recombinant human mite SMIPP-C proteins were produced and used for murine polyclonal antibody production. Immunohistology on skin sections from human patients localised the SMIPP-Cs in the mite gut and in mite faeces within in the epidermal skin burrows. SMIPP-C transcription into mRNA in different life stages was assessed in human and pig mites by reverse transcription followed by droplet digital PCR (ddPCR). High transcription levels of SMIPP-C genes were detected in the adult female life stage in comparison to all other life stages. Conclusions The fact that the SMIPP-Cs are unique to three Sarcoptes varieties, present in all burrowing life stages and highly expressed in the digestive system of the infective adult female life stage may highlight an essential role in parasitism. As they are excreted from the gut in scybala they presumably are able to interact or interfere with host proteins present in the epidermis. Electronic supplementary material The online version of this article (10.1186/s13071-018-2862-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Deepani D Fernando
- QIMR Berghofer Medical Research Institute, Infectious Diseases Program, 300 Herston Road, Herston, Brisbane, QLD, 4006, Australia.,School of Veterinary Sciences, University of Queensland, Gatton, QLD, 4343, Australia.,Department of Veterinary Pathobiology, Faculty of Veterinary Medicine and Animal Science, University of Peradeniya, Peradeniya, Sri Lanka
| | - Simone L Reynolds
- QIMR Berghofer Medical Research Institute, Infectious Diseases Program, 300 Herston Road, Herston, Brisbane, QLD, 4006, Australia
| | - Martha Zakrzewski
- QIMR Berghofer Medical Research Institute, Infectious Diseases Program, 300 Herston Road, Herston, Brisbane, QLD, 4006, Australia
| | - Ehtesham Mofiz
- Bioinformatics Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, 3052, Australia.,Department of Medical Biology, University of Melbourne, Parkville, Victoria, 3010, Australia
| | - Anthony T Papenfuss
- Bioinformatics Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, 3052, Australia.,Peter MacCallum Cancer Centre, Victorian Comprehensive Cancer Centre, Melbourne, 3000, Australia.,Department of Medical Biology, University of Melbourne, Parkville, Victoria, 3010, Australia
| | - Deborah Holt
- Menzies School of Health Research, Charles Darwin University, Casuarina, Northern Territory, Australia
| | - Katja Fischer
- QIMR Berghofer Medical Research Institute, Infectious Diseases Program, 300 Herston Road, Herston, Brisbane, QLD, 4006, Australia.
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Entamoeba histolytica: Overexpression of the gal/galnac lectin, ehcp2 and ehcp5 genes in an in vivo model of amebiasis. Parasitol Int 2016; 65:665-667. [PMID: 27616150 DOI: 10.1016/j.parint.2016.08.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Revised: 07/18/2016] [Accepted: 08/28/2016] [Indexed: 11/21/2022]
Abstract
The parasite Entamoeba histolytica causes intestinal amebiasis and amebic liver abscess as its main extraintestinal manifestation. To study the in vivo events related to inflammation and the interactions between hosts and parasites during amebiasis, we designed a novel model of host-parasite interactions using cellulose membrane dialysis bags containing E. histolytica trophozoites. A bag is placed into the hamster peritoneal cavity, as has been reported in previous studies of programmed cell death (PCD) in E. histolytica trophozoites. To determine if virulence factors such as cysteine proteinases (EhCP2 and EhCP5) and Gal/GalNAc lectin could be involved in the host-parasite interaction using this model, we examined the relative expression of the ehcp2 and ehcp5 genes and the carbohydrate recognition domain (crd) of Gal/GalNAc lectin using real-time quantitative PCR (qRT-PCR). All analyzed genes were over-expressed 0.5h after the initiation of the host-parasite interaction and were then progressively down-regulated. However, Gal/GalNAc lectin had the greatest increase in gene expression 1.5h after host-parasite interaction; Gal/GalNAc lectin had a 250-fold increase with respect to the axenically grown trophozoites, which over-express Gal/GalNAc lectin in in vivo models. These results support the important role of these molecules in the initiation of cell damage by E. histolytica.
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Peroxynitrite and peroxiredoxin in the pathogenesis of experimental amebic liver abscess. BIOMED RESEARCH INTERNATIONAL 2014; 2014:324230. [PMID: 24822193 PMCID: PMC4009108 DOI: 10.1155/2014/324230] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Accepted: 03/12/2014] [Indexed: 12/21/2022]
Abstract
The molecular mechanisms by which Entamoeba histolytica causes amebic liver abscess (ALA) are still not fully understood. Amebic mechanisms of adherence and cytotoxic activity are pivotal for amebic survival but apparently do not directly cause liver abscess. Abundant evidence indicates that chronic inflammation (resulting from an inadequate immune response) is probably the main cause of ALA. Reports referring to inflammatory mechanisms of liver damage mention a repertoire of toxic molecules by the immune response (especially nitric oxide and reactive oxygen intermediates) and cytotoxic substances released by neutrophils and macrophages after being lysed by amoebas (e.g., defensins, complement, and proteases). Nevertheless, recent evidence downplays these mechanisms in abscess formation and emphasizes the importance of peroxynitrite (ONOO−). It seems that the defense mechanism of amoebas against ONOO−, namely, the amebic thioredoxin system (including peroxiredoxin), is superior to that of mammals. The aim of the present text is to define the importance of ONOO− as the main agent of liver abscess formation during amebic invasion, and to explain the superior capacity of amoebas to defend themselves against this toxic agent through the peroxiredoxin and thioredoxin system.
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Carranza-Rosales P, Santiago-Mauricio MG, Guzmán-Delgado NE, Vargas-Villarreal J, Lozano-Garza G, Viveros-Valdez E, Ortiz-López R, Morán-Martínez J, Gandolfi AJ. Induction of virulence factors, apoptosis, and cytokines in precision-cut hamster liver slices infected with Entamoeba histolytica. Exp Parasitol 2012; 132:424-33. [DOI: 10.1016/j.exppara.2012.09.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2012] [Accepted: 09/20/2012] [Indexed: 11/28/2022]
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A genome-wide over-expression screen identifies genes involved in phagocytosis in the human protozoan parasite, Entamoeba histolytica. PLoS One 2012; 7:e43025. [PMID: 22905196 PMCID: PMC3419234 DOI: 10.1371/journal.pone.0043025] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2012] [Accepted: 07/16/2012] [Indexed: 11/23/2022] Open
Abstract
Functional genomics and forward genetics seek to assign function to all known genes in a genome. Entamoeba histolytica is a protozoan parasite for which forward genetics approaches have not been extensively applied. It is the causative agent of amoebic dysentery and liver abscess, and infection is prevalent in developing countries that cannot prevent its fecal-oral spread. It is responsible for considerable global morbidity and mortality. Given that the E. histolytica genome has been sequenced, it should be possible to apply genomic approaches to discover gene function. We used a genome-wide over-expression screen to uncover genes regulating an important virulence function of E. histolytica, namely phagocytosis. We developed an episomal E. histolytica cDNA over-expression library, transfected the collection of plasmids into trophozoites, and applied a high-throughput screen to identify phagocytosis mutants in the population of over-expressing cells. The screen was based on the phagocytic uptake of human red blood cells loaded with the metabolic toxin, tubercidin. Expression plasmids were isolated from trophozoites that survived exposure to tubercidin-charged erythrocytes (phagocytosis mutants), and the cDNAs were sequenced. We isolated the gene encoding profilin, a well-characterized cytoskeleton-regulating protein with a known role in phagocytosis. This supports the validity of our approach. Furthermore, we assigned a phagocytic role to several genes not previously known to function in this manner. To our knowledge, this is the first genome-wide forward genetics screen to be applied to this pathogen. The study demonstrates the power of forward genetics in revealing genes regulating virulence in E. histolytica. In addition, the study validates an E. histolytica cDNA over-expression library as a valuable tool for functional genomics.
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Jørgensen LVG, Buchmann K. Cysteine proteases as potential antigens in antiparasitic DNA vaccines. Vaccine 2011; 29:5575-83. [PMID: 21664399 DOI: 10.1016/j.vaccine.2011.05.091] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2011] [Revised: 05/12/2011] [Accepted: 05/25/2011] [Indexed: 12/17/2022]
Abstract
Cysteine proteases in parasites are potent inducers of vertebrate host immune responses and may under certain circumstances take part in the pathogen's immune evasion strategies. These capacities place these parasite molecules as interesting candidate antigens in antiparasitic vaccines for use in vertebrates. Parasite cysteine proteases are able to skew the Th1/Th2 profile in mammals towards a response which allows sustainable parasite burdens in the host. DNA vaccines are also able to skew the Th1/Th2 profile by different administration techniques and the use of cysteine proteases in these genetic immunizations open perspectives for manipulation of the host immune response towards higher protection.
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Affiliation(s)
- Louise von Gersdorff Jørgensen
- Laboratory of Aquatic Pathobiology, Department of Veterinary Disease Biology, Faculty of Life Sciences, University of Copenhagen, Denmark.
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Current and future perspectives on the chemotherapy of the parasitic protozoa Trichomonas vaginalis and Entamoeba histolytica. Future Med Chem 2009; 1:619-43. [DOI: 10.4155/fmc.09.59] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Trichomonas vaginalis and Entamoeba histolytica are clinically important protozoa that affect humans. T. vaginalis produces sexually transmitted infections and E. histolytica is the causative agent of amebic dysentery. Metronidazole, a compound first used to treat T. vaginalis in 1959, is still the main drug used worldwide to treat these pathogens. It is essential to find new biochemical differences in these organisms that could be exploited to develop new antiprotozoal chemotherapeutics. Recent findings associated with T. vaginalis and E. histolytica biochemistry and host–pathogen interactions are surveyed. Knowledge concerning the biochemistry of these parasites is serving to form the foundation for the development of new approaches to control these important human pathogens.
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Freitas MAR, Fernandes HC, Calixto VC, Martins AS, Silva EF, Pesquero JL, Gomes MA. Entamoeba histolytica: cysteine proteinase activity and virulence. Focus on cysteine proteinase 5 expression levels. Exp Parasitol 2009; 122:306-9. [PMID: 19389401 DOI: 10.1016/j.exppara.2009.04.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2008] [Revised: 03/27/2009] [Accepted: 04/13/2009] [Indexed: 11/25/2022]
Abstract
Cysteine proteinase (CP) activity and CP5 mRNA levels were analyzed in eleven samples of Entamoeba histolytica isolated from patients presenting different clinical profiles. The virulence degree of the isolates, determined in hamster liver, correlated well with the clinical form of the patient and culture conditions. CP5 mRNA levels were also determined in sample freshly picked up directly from liver amoebic abscess. Differences were not observed in the levels of CP5 mRNA and CP specific activity among the cultured samples. However, different levels of CP5 mRNA were observed in trophozoite freshly isolated from hepatic amoebic lesions. These results reinforce the importance of CP5 for the virulence of amoebae and the need for studies with the parasite present in lesions to validate mechanisms involved in pathogenesis of amoebiasis.
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Affiliation(s)
- Michelle A R Freitas
- Departamento de Parasitologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Av. Antonio Carlos, 6627, 31270-901 Belo Horizonte, MG, Brazil
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13
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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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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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15
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Ramos E, Olivos-García A, Nequiz M, Saavedra E, Tello E, Saralegui A, Montfort I, Pérez Tamayo R. Entamoeba histolytica: apoptosis induced in vitro by nitric oxide species. Exp Parasitol 2007; 116:257-65. [PMID: 17336295 DOI: 10.1016/j.exppara.2007.01.011] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2006] [Revised: 01/08/2007] [Accepted: 01/11/2007] [Indexed: 11/30/2022]
Abstract
Apoptosis has been described in some parasites like Leishmania, Trypanosoma, and Trichomonas. This phenomenon has not been observed yet in Entamoeba histolytica. This work analyzed the in vitro effect of sodium nitroprusside, sodium nitrite and sodium nitrate (NOs) on E. histolytica apoptosis. Parasites incubated for 1h with NOs revealed apoptosis 6h later (95% viability), demonstrated by YOPRO-1, TUNEL, DNA fragmentation and low ATP levels. The caspase inhibitor Z-VAD-FMK inhibited total intracellular cysteine protease activity (CPA) but had no effect on apoptosis. When treated with NOs some amebic functions like complement resistance and hemolytic activity decreased but CPA and erythrophagocytosis remained unchanged. After treatment in vitro with NOs, parasite death was almost complete at 24h; but when injected into hamster livers they disappeared in less than 6h. These results show that apoptosis is induced in vitro by NOs in E. histolytica and renders them incapable of surviving in hamster's livers.
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Affiliation(s)
- Espiridión Ramos
- Departamento de Medicina, Experimental, Facultad de Medicina;Universidad Nacional Autónoma de México, México DF, Mexico
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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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17
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Tsutsumi V, Shibayama M. Experimental amebiasis: a selected review of some in vivo models. Arch Med Res 2006; 37:210-20. [PMID: 16380321 DOI: 10.1016/j.arcmed.2005.09.011] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2005] [Accepted: 09/23/2005] [Indexed: 10/25/2022]
Abstract
The use of in vivo animal models in amebiasis has contributed significantly to the knowledge of this common human parasitic disease. Although there is no animal model that mimics the whole cycle of the human disease, the use of different susceptible and resistant laboratory animals and the availability for many years of techniques for the axenic culture of trophozoites of Entamoeba histolytica have allowed a better understanding of the parasite and the host-parasite relationship. The recent introduction of frontier methodologies in biology has increased our comprehension of this parasite. New information on the cellular and molecular biology and genetics of this organism has been extensively reported, and much of this has clearly required the more frequent use of animal models to verify specific facts. Based on experimental animals characterized previously, the introduction of new animal models with genetic or surgical modifications, especially in mice, has allowed a more adequate analysis of the mechanisms of pathogenesis. Multiple factors have been considered in the promotion of the invasiveness and virulence of E. histolytica. Additionally, the immunological and physiological responses of the host, depending on the environmental conditions, lead to the establishment or the rejection of the parasite. The role of inflammatory reaction to amebic infection constitutes one of the controversies that has been studied by several authors. In susceptible animals (hamsters and gerbils), inflammatory cell damage seems to be related to target cell lysis, while in resistant animals (mice), inflammatory cells appear to protect the host by lysing the parasite. Presently, the involvement of various substances in the development of lesions including lectins, proteases, amebapores, promoters of apoptosis, cytokines, nitric oxide, etc., is being examined using different in vivo models.
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Affiliation(s)
- Víctor Tsutsumi
- Departamento de Patología Experimental, CINVESTAV-IPN, México, D.F., México.
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18
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Powell RR, Welter BH, Hwu R, Bowersox B, Attaway C, Temesvari LA. Entamoeba histolytica: FYVE-finger domains, phosphatidylinositol 3-phosphate biosensors, associate with phagosomes but not fluid filled endosomes. Exp Parasitol 2006; 112:221-31. [PMID: 16387299 DOI: 10.1016/j.exppara.2005.11.013] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2005] [Revised: 11/09/2005] [Accepted: 11/10/2005] [Indexed: 11/24/2022]
Abstract
Endocytosis is an important virulence function for Entamoeba histolytica, the causative agent of amoebic dysentery. Although a number of E. histolytica proteins that regulate this process have been identified, less is known about the role of lipids. In other systems, phosphatidylinositol 3-phosphate (PI3P), a product of phosphatidylinositol 3-kinase (PI 3-kinase), has been shown to be required for endocytosis. FYVE-finger domains are protein motifs that bind specifically to PI3P. Using a PI3P biosensor consisting of glutathione-S-transferase (GST) fused to two tandem FYVE-finger domains, we have localized PI3P to phagosomes but not fluid-phase pinosomes in E. histolytica, suggesting a role for PI3P in phagocytosis. Treatment of cells with PI 3-kinase inhibitors impaired GST-2 x FYVE-phagosome association supporting the authenticity of the biosensor staining. However, treatment with PI 3-kinase inhibitors did not inhibit E. histolytica-particle interaction, indicating that PI3P is not required for the initial step, but is required for subsequent steps of phagocytosis.
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Affiliation(s)
- R R Powell
- Department of Biological Sciences, Clemson University, Clemson, SC 29634, USA
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McKerrow JH, Caffrey C, Kelly B, Loke P, Sajid M. PROTEASES IN PARASITIC DISEASES. ANNUAL REVIEW OF PATHOLOGY-MECHANISMS OF DISEASE 2006; 1:497-536. [PMID: 18039124 DOI: 10.1146/annurev.pathol.1.110304.100151] [Citation(s) in RCA: 283] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- James H. McKerrow
- Department of Pathology and the Sandler Center, University of California, San Francisco, San Francisco, California 94143; , , ,
| | - Conor Caffrey
- Department of Pathology and the Sandler Center, University of California, San Francisco, San Francisco, California 94143; , , ,
| | - Ben Kelly
- Department of Pathology and the Sandler Center, University of California, San Francisco, San Francisco, California 94143; , , ,
| | - P'ng Loke
- Department of Pathology and the Sandler Center, University of California, San Francisco, San Francisco, California 94143; , , ,
| | - Mohammed Sajid
- Department of Pathology and the Sandler Center, University of California, San Francisco, San Francisco, California 94143; , , ,
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Pérez-Tamayo R, Montfort I, García AO, Ramos E, Ostria CB. Pathogenesis of Acute Experimental Liver Amebiasis. Arch Med Res 2006; 37:203-9. [PMID: 16380320 DOI: 10.1016/j.arcmed.2005.10.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2005] [Accepted: 10/21/2005] [Indexed: 10/25/2022]
Abstract
Classical descriptions of the pathology of amebiasis portray the parasite as the cause of tissue damage and destruction, and in recent years a number of amebic molecules have been identified as virulence factors. In this review we describe a series of experiments that suggest a more complex host-parasite relation, at least during the early stages of acute experimental amebic liver abscess in hamsters. The problems of extrapolating experiments in vitro to explain observations in vivo are discussed. The role of amebic cysteine proteases is examined and evidence presented to suggest that they are primarily related not to tissue damage but to amebic survival, which is required for the progression of the lesion. Inflammation is shown to be not only the major cause of tissue damage but also an absolute requirement for amebic survival in the liver, whereas complement and ischemia are not involved in the disappearance of the parasite in the absence of inflammation.
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Affiliation(s)
- Ruy Pérez-Tamayo
- Department of Experimental Medicine, National Autonomous University Medical School, Mexico City, Mexico.
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