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Loufouma-Mbouaka A, Martín-Pérez T, Köhsler M, Danisman Z, Schwarz M, Mazumdar R, Samba-Louaka A, Walochnik J. Characterization of novel extracellular proteases produced by Acanthamoeba castellanii after contact with human corneal epithelial cells and their relevance to pathogenesis. Parasit Vectors 2024; 17:242. [PMID: 38812022 PMCID: PMC11137893 DOI: 10.1186/s13071-024-06304-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Accepted: 04/24/2024] [Indexed: 05/31/2024] Open
Abstract
BACKGROUND Proteases produced by Acanthamoeba spp. play an important role in their virulence and may be the key to understanding Acanthamoeba pathogenesis; thus, increasing attention has been directed towards these proteins. The present study aimed to investigate the lytic factors produced by Acanthamoeba castellanii during the first hours of in vitro co-culture with human corneal epithelial cells (HCECs). METHODS We used one old and one recent Acanthamoeba isolate, both from patients with severe keratitis, and subsets of these strains with enhanced pathogenic potential induced by sequential passaging over HCEC monolayers. The proteolytic profiles of all strains and substrains were examined using 1D in-gel zymography. RESULTS We observed the activity of additional proteases (ranging from 33 to 50 kDa) during the early interaction phase between amoebae and HCECs, which were only expressed for a short time. Based on their susceptibilities to protease inhibitors, these proteases were characterized as serine proteases. Protease activities showed a sharp decline after 4 h of co-incubation. Interestingly, the expression of Acanthamoeba mannose-binding protein did not differ between amoebae in monoculture and those in co-culture. Moreover, we observed the activation of matrix metalloproteinases in HCECs after contact with Acanthamoeba. CONCLUSIONS This study revealed the involvement of two novel serine proteases in Acanthamoeba pathogenesis and suggests a pivotal role of serine proteases during Acanthamoeba-host cell interaction, contributing to cell adhesion and lysis.
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Affiliation(s)
- Alvie Loufouma-Mbouaka
- Center for Pathophysiology, Infectiology and Immunology, Institute of Specific Prophylaxis and Tropical Medicine, Medical University of Vienna, Vienna, Austria
| | - Tania Martín-Pérez
- Center for Pathophysiology, Infectiology and Immunology, Institute of Specific Prophylaxis and Tropical Medicine, Medical University of Vienna, Vienna, Austria
| | - Martina Köhsler
- Center for Pathophysiology, Infectiology and Immunology, Institute of Specific Prophylaxis and Tropical Medicine, Medical University of Vienna, Vienna, Austria
| | - Zeynep Danisman
- Center for Pathophysiology, Infectiology and Immunology, Institute of Specific Prophylaxis and Tropical Medicine, Medical University of Vienna, Vienna, Austria
| | - Maya Schwarz
- Center for Pathophysiology, Infectiology and Immunology, Institute of Specific Prophylaxis and Tropical Medicine, Medical University of Vienna, Vienna, Austria
| | - Rounik Mazumdar
- Max Perutz Labs Vienna, Department of Medical Biochemistry, Medical University of Vienna, Vienna, Austria
- GenomeByte Ltd, London, UK
| | - Ascel Samba-Louaka
- Laboratoire Ecologie Et Biologie Des Interactions, Université de Poitiers, UMR CNRS, 7267, Poitiers, France
| | - Julia Walochnik
- Center for Pathophysiology, Infectiology and Immunology, Institute of Specific Prophylaxis and Tropical Medicine, Medical University of Vienna, Vienna, Austria.
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Salazar-Villatoro L, Chávez-Munguía B, Guevara-Estrada CE, Lagunes-Guillén A, Hernández-Martínez D, Castelan-Ramírez I, Omaña-Molina M. Taurine, a Component of the Tear Film, Exacerbates the Pathogenic Mechanisms of Acanthamoeba castellanii in the Ex Vivo Amoebic Keratitis Model. Pathogens 2023; 12:1049. [PMID: 37624009 PMCID: PMC10458499 DOI: 10.3390/pathogens12081049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2023] [Revised: 08/13/2023] [Accepted: 08/14/2023] [Indexed: 08/26/2023] Open
Abstract
Acanthamoeba spp. is the etiological agent of amoebic keratitis. In this study, the effect of taurine in physiological concentrations in tears (195 μM) on trophozoites of Acanthamoeba castellanii through the ex vivo amoebic keratitis model was evaluated. Trophozoites were coincubated with the Syrian golden hamster cornea (Mesocricetus auratus) for 3 and 6 h. Group 1: Control (-). Corneas coincubated with amoebic culture medium and taurine. Group 2: Control (+). Corneas coincubated with trophozoites without taurine. Group 3: Corneas coincubated with taurine 15 min before adding trophozoites. Group 4: Trophozoites coincubated 15 min with taurine before placing them on the cornea. Group 5: Corneas coincubated for 15 min with trophozoites; subsequently, taurine was added. Results are similar for both times, as evaluated by scanning electron microscopy. As expected, in the corneas of Group 1, no alterations were observed in the corneal epithelium. In the corneas of Group 2, few adhered trophozoites were observed on the corneal surface initiating migrations through cell junctions as previously described; however, in corneas of Groups 3, 4 and 5, abundant trophozoites were observed, penetrating through different corneal cell areas, emitting food cups and destabilizing corneal surface in areas far from cell junctions. Significant differences were confirmed in trophozoites adherence coincubated with taurine (p < 0.05). Taurine does not prevent the adhesion and invasion of the amoebae, nor does it favor its detachment once these have adhered to the cornea, suggesting that taurine in the physiological concentrations found in tears stimulates pathogenic mechanisms of A. castellanii.
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Affiliation(s)
- Lizbeth Salazar-Villatoro
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del IPN, Ciudad de Mexico 07360, Mexico; (L.S.-V.); (B.C.-M.); (A.L.-G.)
| | - Bibiana Chávez-Munguía
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del IPN, Ciudad de Mexico 07360, Mexico; (L.S.-V.); (B.C.-M.); (A.L.-G.)
| | - Celia Esther Guevara-Estrada
- Laboratorio de Amibas Anfizóicas, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Tlalnepantla 54090, Mexico; (C.E.G.-E.); (D.H.-M.); (I.C.-R.)
| | - Anel Lagunes-Guillén
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del IPN, Ciudad de Mexico 07360, Mexico; (L.S.-V.); (B.C.-M.); (A.L.-G.)
| | - Dolores Hernández-Martínez
- Laboratorio de Amibas Anfizóicas, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Tlalnepantla 54090, Mexico; (C.E.G.-E.); (D.H.-M.); (I.C.-R.)
| | - Ismael Castelan-Ramírez
- Laboratorio de Amibas Anfizóicas, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Tlalnepantla 54090, Mexico; (C.E.G.-E.); (D.H.-M.); (I.C.-R.)
| | - Maritza Omaña-Molina
- Laboratorio de Amibas Anfizóicas, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Tlalnepantla 54090, Mexico; (C.E.G.-E.); (D.H.-M.); (I.C.-R.)
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3
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Loufouma Mbouaka A, Lesiak-Markowicz I, Heredero-Bermejo I, Mazumdar R, Walochnik J, Martín-Pérez T. Assessing Acanthamoeba cytotoxicity: comparison of common cell viability assays. Front Microbiol 2023; 14:1175469. [PMID: 37180263 PMCID: PMC10167018 DOI: 10.3389/fmicb.2023.1175469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Accepted: 04/03/2023] [Indexed: 05/16/2023] Open
Abstract
Background In vitro models for studying interactions between Acanthamoeba and host cells are crucial for understanding the pathomechanism of Acanthamoeba and assessing differences between strains and cell types. The virulence of Acanthamoeba strains is usually assessed and monitored by using cell cytotoxicity assays. The aim of the present study was to evaluate and compare the most widely used cytotoxicity assays for their suitability to assess Acanthamoeba cytopathogenicity. Methods The viability of human corneal epithelial cells (HCECs) after co-culture with Acanthamoeba was evaluated in phase contrast microscopy. Results It was shown that Acanthamoeba is unable to considerably reduce the tetrazolium salt and the NanoLuc® Luciferase prosubstrate to formazan and the luciferase substrate, respectively. This incapacity helped to generate a cell density-dependent signal allowing to accurately quantify Acanthamoeba cytotoxicity. The lactate dehydrogenase (LDH) assay led to an underestimation of the cytotoxic effect of Acanthamoeba on HCECs since their co-incubation negatively affected the lactate dehydrogenase activity. Discussion Our findings demonstrate that cell-based assays using the aqueous soluble tetrazolium-formazan, and the NanoLuc® Luciferase prosubstrate products, in contrast to LDH, are excellent markers to monitor the interaction of Acanthamoeba with human cell lines and to determine and quantify effectively the cytotoxic effect induced by the amoebae. Furthermore, our data indicate that protease activity may have an impact on the outcome and thus the reliability of these tests.
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Affiliation(s)
- Alvie Loufouma Mbouaka
- Center for Pathophysiology, Infectiology and Immunology, Institute of Specific Prophylaxis and Tropical Medicine, Medical University of Vienna, Vienna, Austria
| | - Iwona Lesiak-Markowicz
- Center for Pathophysiology, Infectiology and Immunology, Institute of Specific Prophylaxis and Tropical Medicine, Medical University of Vienna, Vienna, Austria
| | - Irene Heredero-Bermejo
- Department of Biomedicine and Biotechnology, Faculty of Pharmacy, University of Alcalá, Madrid, Spain
| | - Rounik Mazumdar
- Max Perutz Labs Vienna, Department of Medical Biochemistry, Medical University of Vienna, Vienna, Austria
| | - Julia Walochnik
- Center for Pathophysiology, Infectiology and Immunology, Institute of Specific Prophylaxis and Tropical Medicine, Medical University of Vienna, Vienna, Austria
| | - Tania Martín-Pérez
- Center for Pathophysiology, Infectiology and Immunology, Institute of Specific Prophylaxis and Tropical Medicine, Medical University of Vienna, Vienna, Austria
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de Souza Fernandes N, Caliari MV, Oliveira FMS, Neto ABC, Rodrigues IA, Furst C, Costa AO. Experimental keratitis induced in rat by Acanthamoeba from distinct morphological groups/genotypes: a histological and immunohistochemical evaluation. Parasitol Res 2023; 122:1167-1175. [PMID: 36922408 DOI: 10.1007/s00436-023-07817-3] [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: 12/17/2022] [Accepted: 03/02/2023] [Indexed: 03/18/2023]
Abstract
Species of the genus Acanthamoeba are free-living protozoans that occasionally act as parasites, causing a severe, progressive corneal infection termed Acanthamoeba keratitis (AK). The variable pathogenic potential among Acanthamoeba lineages has been shown by in vitro assays, but little is known about the behavior of different strains in animal models of AK. This work aimed to evaluate the infectivity of Acanthamoeba from distinct morphological groups and genotypes in a rat model of AK and apply an immunohistochemical technique for histological characterization of the lesions. Only a strain classified as group I/genotype T17, isolated from a soil source, caused ulcerated corneal lesions in two Wistar rats (n = 9) subjected to intrastromal inoculation. Two strains derived from AK human cases (group II/genotype T4 and group III/genotype T5) did not induce corneal lesions in the rats. A previous association of group II/genotype T4 trophozoites with lethally irradiated Escherichia coli did not influence the infectivity. A hyperimmune serum produced in Wistar rats was validated by an immunocytochemical technique using the three distinct strains and then applied for immunohistochemistry. The abundance of antigenic residues was observed in both corneas with keratitis, suggesting that the infectious process tended to resolve. Despite the low infection rate of the AK Wistar rat model, we produced an immunochemical tool with a potential diagnostic application. We also showed for the first time the ability of Acanthamoeba from T17 genotype to cause AK in experimental conditions.
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Affiliation(s)
- Norberto de Souza Fernandes
- Departamento de Análises Clínicas e Toxicológicas, Faculdade de Farmácia, Universidade Federal de Minas Gerais (UFMG), Minas Gerais, Belo Horizonte, Brazil
| | - Marcelo Vidigal Caliari
- Departamento de Patologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, Minas Gerais, Brazil
| | - Fabricio Marcos Silva Oliveira
- Departamento de Patologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, Minas Gerais, Brazil
| | | | - Isabela Aurora Rodrigues
- Departamento de Análises Clínicas e Toxicológicas, Faculdade de Farmácia, Universidade Federal de Minas Gerais (UFMG), Minas Gerais, Belo Horizonte, Brazil
| | - Cinthia Furst
- Santa Casa de Misericórdia, Belo Horizonte, Minas Gerais, Brazil
| | - Adriana Oliveira Costa
- Departamento de Análises Clínicas e Toxicológicas, Faculdade de Farmácia, Universidade Federal de Minas Gerais (UFMG), Minas Gerais, Belo Horizonte, Brazil.
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5
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Wang YJ, Chen CH, Chen JW, Lin WC. Commensals Serve as Natural Barriers to Mammalian Cells during Acanthamoeba castellanii Invasion. Microbiol Spectr 2021; 9:e0051221. [PMID: 34935418 PMCID: PMC8693914 DOI: 10.1128/spectrum.00512-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2021] [Accepted: 11/02/2021] [Indexed: 12/23/2022] Open
Abstract
Acanthamoeba castellanii is a free-living, pathogenic ameba found in the soil and water. It invades the body through ulcerated skin, the nasal passages, and eyes and can cause blinding keratitis and granulomatous encephalitis. However, the mechanisms underlying the opportunistic pathogenesis of A. castellanii remain unclear. In this study, we observed that commensal bacteria significantly reduced the cytotoxicity of the ameba on mammalian cells. This effect occurred in the presence of both Gram-positive and Gram-negative commensals. Additionally, commensals mitigated the disruption of cell junctions. Ex vivo experiments on mouse eyeballs further showed that the commensals protected the corneal epithelial layer. Together, these findings indicate that A. castellanii is pathogenic to individuals with a dysbiosis of the microbiota at infection sites, further highlighting the role of commensals as a natural barrier during parasite invasion. IMPORTANCE Acanthamoeba castellanii, an opportunistic protozoan widely present in the environment, can cause Acanthamoeba keratitis and encephalitis in humans. However, only a few reports describe how the ameba acts as an opportunistic pathogen. Our study showed that the normal microbiota interfered with the cytotoxicity of Acanthamoeba, persevered during Acanthamoeba invasion, and reduced corneal epithelium peeling in the mouse eyeball model. This suggests that commensals may act as a natural barrier against Acanthamoeba invasion. In future, individuals who suffer from Acanthamoeba keratitis should be examined for microbiota absence or dysbiosis to reduce the incidence of Acanthamoeba infection in clinical settings.
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Affiliation(s)
- Yu-Jen Wang
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan
- Department of Clinical Laboratory, Chest Hospital, Ministry of Health and Welfare, Tainan, Taiwan
| | - Chun-Hsien Chen
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Jenn-Wei Chen
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan
- Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Wei-Chen Lin
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan
- Department of Parasitology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
- Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
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Crary MJ, Walters R, Shannon P, Gabriel MM. Variables Affecting the Recovery of Acanthamoeba Trophozoites. Pathogens 2021; 10:221. [PMID: 33670669 PMCID: PMC7922685 DOI: 10.3390/pathogens10020221] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 02/15/2021] [Accepted: 02/16/2021] [Indexed: 11/28/2022] Open
Abstract
While the results of Acanthamoeba testing have been extensively published, laboratories conducting such testing are left to develop their own methods in the absence of a standardized methodology. The wide disparity of methods has resulted in equally inconsistent reported results for contact lens care (CLC) products. This study's objective was to determine the source of these discrepancies by evaluating basic Acanthamoeba biology and their impact on antimicrobial efficacy testing, including the ability of a recovery method to stimulate a single trophozoite to proliferate. Antimicrobial efficacy testing was conducted using well-published Acanthamoeba strains, storage conditions, and growth-based recovery methods. To identify variables that influence results, test solutions with low Acanthamoeba disinfection rates were utilized to prevent differences from being masked by high log reductions. In addition, single-cell proliferation assays were executed to understand the growth requirements to stimulate trophozoite propagation in two recovery methods. These studies indicated that both nutrient density (>106 CFU) and the length of plate incubation (at least 14 days) could significantly influence the accurate recovery of trophozoites. Together, this study emphasizes the need to understand how Acanthamoeba trophozoites biology can impact test methods to create divergent results.
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Affiliation(s)
- Monica J. Crary
- R&D Microbiology, Alcon Research, LLC, Fort Worth, TX 76134, USA; (R.W.); (P.S.); (M.M.G.)
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Carvalho-Silva AC, Coelho CH, Cirelli C, Crepaldi F, Rodrigues-Chagas IA, Furst C, Pimenta DC, Toledo JSD, Fernandes AP, Costa AO. Differential expression of Acanthamoeba castellanii proteins during amoebic keratitis in rats. Exp Parasitol 2020; 221:108060. [PMID: 33338467 DOI: 10.1016/j.exppara.2020.108060] [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: 04/01/2020] [Revised: 11/04/2020] [Accepted: 12/13/2020] [Indexed: 11/25/2022]
Abstract
Amoebic keratitis (AK) is a sight-threatening infection characterized by a severe inflammation of the cornea, caused by the free-living protozoan of the genus Acanthamoeba. Identification of amoebic proteins involved in AK pathogenesis may help to elucidate molecular mechanisms of infection and contribute to indicate diagnostic and therapeutic targets. In this study, we evaluated changes in the expression profile of Acanthamoeba proteins triggered by the invasive process, using an approach involving two-dimensional polyacrylamide gel electrophoresis (2DE PAGE), followed by mass spectrometry identification (ESI-IT-TOF LC-MSn). AK was induced by intrastromal inoculation in Wistar rats, using trophozoites from a T4 genotype, human case-derived A. castellanii strain under prolonged axenic culture. Cultures re-isolated from the lesions after two successive passages in the animals were used as biological triplicate for proteomic experiments. Analysis of the protein profile comparing long-term and re-isolated cultures indicated 62 significant spots, from which 27 proteins could be identified in the Acanthamoeba proteome database. Five of them (Serpin, Carboxypeptidase A1, Hypothetical protein, Calponin domain-containing protein, aldo/keto reductase) were exclusively found in the re-isolated trophozoites. Our analysis also revealed that a concerted modulation of several biochemical pathways is triggered when A. castellanii switches from a free-living style to a parasitic mode, including energetic metabolism, proteolytic activity, control of gene expression, protein degradation and methylation of DNA, which may be also involved in gain of virulence in an animal model of AK.
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Affiliation(s)
- Ana Carolina Carvalho-Silva
- Department of Clinical and Toxicological Analysis, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Camila H Coelho
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Cecília Cirelli
- Department of Clinical and Toxicological Analysis, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Frederico Crepaldi
- Department of Clinical and Toxicological Analysis, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | | | - Cinthia Furst
- Department of Pathology, Health Sciences Center, Federal University of Espírito Santo, Vitória, ES, Brazil
| | | | - Juliano Simões de Toledo
- Department of Clinical and Toxicological Analysis, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Ana Paula Fernandes
- Department of Clinical and Toxicological Analysis, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Adriana Oliveira Costa
- Department of Clinical and Toxicological Analysis, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil.
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Wang Z, Wu D, Tachibana H, Feng M, Cheng XJ. Identification and biochemical characterisation of Acanthamoeba castellanii cysteine protease 3. Parasit Vectors 2020; 13:592. [PMID: 33228764 PMCID: PMC7685649 DOI: 10.1186/s13071-020-04474-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 11/05/2020] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Acanthamoeba spp. are free-living amoeba that are ubiquitously distributed in the environment. This study examines pathogenic Acanthamoeba cysteine proteases (AcCPs) belonging to the cathepsin L-family and explores the mechanism of AcCP3 interaction with host cells. METHODS Six AcCP genes were amplified by polymerase chain reaction (PCR). Quantitative real-time PCR was used to analyse the relative mRNA expression of AcCPs during the encystation process and between pre- and post-reactivated trophozoites. To further verify the role of AcCP3 in these processes, AcCP3 recombinant proteins were expressed in Escherichia coli, and the hydrolytic activity of AcCP3 was determined. The influence of the AcCP3 on the hydrolytic activity of trophozoites and the toxicity of trophozoites to human corneal epithelial cells (HCECs) was examined by inhibiting AcCP3 expression using siRNA. Furthermore, the levels of p-Raf and p-Erk were examined in HCECs following coculture with AcCP3 gene knockdown trophozoites by Western blotting. RESULTS During encystation, five out of six AcCPs exhibited decreased expression, and only AcCP6 was substantially up-regulated at the mRNA level, indicating that most AcCPs were not directly correlated to encystation. Furthermore, six AcCPs exhibited increased expression level following trophozoite reactivation with HEp-2 cells, particularly AcCP3, indicating that these AcCPs might be virulent factors. After refolding of recombinant AcCP3 protein, the 27 kDa mature protein from the 34 kDa pro-protein hydrolysed host haemoglobin, collagen and albumin and showed high activity in an acidic environment. After AcCP3 knockdown, the hydrolytic activity of trophozoite crude protein against gelatin was decreased, suggesting that these trophozoites had decreased toxicity. Compared with untreated trophozoites or negative control siRNA-treated trophozoites, AcCP3-knockdown trophozoites were less able to penetrate and damage monolayers of HCECs. Western blot analysis showed that the activation levels of the Ras/Raf/Erk/p53 signalling pathways in HCECs decreased after inhibiting the expression of trophozoite AcCP3. CONCLUSIONS AcCP6 was correlated to encystation. Furthermore, AcCP3 was a virulent factor in trophozoites and participated in the activation of the Ras/Raf/Erk/p53 signalling pathways of host cells.
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Affiliation(s)
- Zhixin Wang
- Department of Medical Microbiology and Parasitology, School of Basic Medical Sciences, Fudan University, Shanghai, 200032, China
| | - Duo Wu
- Department of Medical Microbiology and Parasitology, School of Basic Medical Sciences, Fudan University, Shanghai, 200032, China
| | - Hiroshi Tachibana
- Department of Infectious Diseases, Tokai University School of Medicine, Isehara, Kanagawa, 259-1193, Japan
| | - Meng Feng
- Department of Medical Microbiology and Parasitology, School of Basic Medical Sciences, Fudan University, Shanghai, 200032, China.
| | - Xun-Jia Cheng
- Department of Medical Microbiology and Parasitology, School of Basic Medical Sciences, Fudan University, Shanghai, 200032, China.
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Faber K, Zorzi GK, Brazil NT, Rott MB, Teixeira HF. siRNA-loaded liposomes: Inhibition of encystment of Acanthamoeba
and toxicity on the eye surface. Chem Biol Drug Des 2017; 90:406-416. [DOI: 10.1111/cbdd.12958] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 12/23/2016] [Accepted: 01/03/2017] [Indexed: 01/20/2023]
Affiliation(s)
- Kathrin Faber
- Graduate Program in Pharmaceutical Sciences; School of Pharmacy; Federal University of Rio Grande do Sul; Porto Alegre Brazil
- Institute of Pharmacology and Toxicology; Universitätsmedizin Berlin; Berlin Germany
| | - Giovanni K. Zorzi
- Graduate Program in Pharmaceutical Sciences; School of Pharmacy; Federal University of Rio Grande do Sul; Porto Alegre Brazil
| | - Nathalya T. Brazil
- Graduate Program in Pharmaceutical Sciences; School of Pharmacy; Federal University of Rio Grande do Sul; Porto Alegre Brazil
| | - Marilise B. Rott
- Graduate Program of Agricultural and Environmental Microbiology; Institute of Basic Health Sciences; Porto Alegre Brazil
| | - Helder F. Teixeira
- Graduate Program in Pharmaceutical Sciences; School of Pharmacy; Federal University of Rio Grande do Sul; Porto Alegre Brazil
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Bridle AR, Davenport DL, Crosbie PBB, Polinski M, Nowak BF. Neoparamoeba perurans loses virulence during clonal culture. Int J Parasitol 2015; 45:575-8. [PMID: 26008963 DOI: 10.1016/j.ijpara.2015.04.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Revised: 04/20/2015] [Accepted: 04/23/2015] [Indexed: 10/23/2022]
Abstract
Amoebic Gill Disease affects farmed salmonids and is caused by Neoparamoeba perurans. Clonal cultures of this amoeba have been used for challenge experiments, however the effect of long-term culture on virulence has not been investigated. Here we show, using in vitro and in vivo methods, that a clone of N. perurans which was virulent 70 days after clonal culture lost virulence after 3 years in clonal culture. We propose that this is related either to the lack of attachment to the gills or the absence of an extracellular product, as shown by the lack of cytopathic effect on Chinook salmon embryo cells. The avirulent clonal culture of N. perurans allowed us to propose two potential virulence mechanisms/factors involved in Amoebic Gill Disease and is an invaluable tool for host-pathogen studies of Amoebic Gill Disease.
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Affiliation(s)
- Andrew R Bridle
- Institute of Marine and Antarctic Studies, University of Tasmania, Launceston, Tasmania, Australia
| | - Danielle L Davenport
- Institute of Marine and Antarctic Studies, University of Tasmania, Launceston, Tasmania, Australia
| | - Philip B B Crosbie
- Institute of Marine and Antarctic Studies, University of Tasmania, Launceston, Tasmania, Australia
| | - Mark Polinski
- Institute of Marine and Antarctic Studies, University of Tasmania, Launceston, Tasmania, Australia
| | - Barbara F Nowak
- Institute of Marine and Antarctic Studies, University of Tasmania, Launceston, Tasmania, Australia.
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Veríssimo CDM, Maschio VJ, Correa APF, Brandelli A, Rott MB. Infection in a rat model reactivates attenuated virulence after long-term axenic culture of Acanthamoeba spp. Mem Inst Oswaldo Cruz 2015; 108:832-5. [PMID: 24271042 PMCID: PMC3970641 DOI: 10.1590/0074-0276130099] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2012] [Accepted: 03/26/2013] [Indexed: 11/22/2022] Open
Abstract
Prolonged culturing of many microorganisms leads to the loss of virulence and a reduction of their infective capacity. However, little is known about the changes in the pathogenic strains of Acanthamoeba after long culture periods. Our study evaluated the effect of prolonged culturing on the invasiveness of different isolates of Acanthamoeba in an in vivo rat model. ATCC strains of Acanthamoeba, isolates from the environment and clinical cases were evaluated. The in vivo model was effective in establishing the infection and differentiating the pathogenicity of the isolates and re-isolates. The amoebae cultured in the laboratory for long periods were less virulent than those that were recently isolated, confirming the importance of passing Acanthamoeba strains in animal models.
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12
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Mycobacterium avium infections of Acanthamoeba strains: host strain variability, grazing-acquired infections, and altered dynamics of inactivation with monochloramine. Appl Environ Microbiol 2010; 76:6685-8. [PMID: 20709834 DOI: 10.1128/aem.00644-10] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Stable Mycobacterium avium infections of several Acanthamoeba strains were characterized by increased infection resistance of recent environmental isolates and reduced infectivity in the presence of other bacteria. Exposure of M. avium in coculture with Acanthamoeba castellanii to monochloramine yielded inactivation kinetics markedly similar to those observed for A. castellanii alone.
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13
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Nagyová V, Nagy A, Timko J. Morphological, physiological and molecular biological characterisation of isolates from first cases of Acanthamoeba keratitis in Slovakia. Parasitol Res 2010; 106:861-72. [PMID: 20127114 DOI: 10.1007/s00436-010-1731-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2009] [Accepted: 01/04/2010] [Indexed: 11/29/2022]
Abstract
Acanthamoeba keratitis (AK) is a relatively rare disease worldwide. Over the past 10 years, five cases of AK were reported in Slovakia. Four preserved Slovak strains and one strain from the Czech Republic isolated from corneal scrapes of patients with AK are characterised in this study. Genotype identification of isolates is based on sequences of the PCR amplimer GTSA.B1 amplified from 18S ribosomal DNA. A strain isolated from the first patient in 1999 was classified as a rare sequence type T15. This is just the second report in which genotype T15 has been associated with AK. The other three Slovak strains were identified as belonging to the most common genotype T4. The only strain originating from the Czech Republic was classified as sporadically appearing sequence type T3. All isolates were also studied for their temperature tolerance and growth characteristics. The cythopatic effect was tested in vitro on Vero cell cultures.
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Affiliation(s)
- Viera Nagyová
- Public Health Authority of the Slovak Republic, Bratislava, Slovakia.
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14
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Pumidonming W, Koehsler M, Walochnik J. Acanthamoeba strains show reduced temperature tolerance after long-term axenic culture. Parasitol Res 2009; 106:553-9. [PMID: 20012991 DOI: 10.1007/s00436-009-1694-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2009] [Accepted: 11/20/2009] [Indexed: 11/24/2022]
Abstract
Acanthamoeba is a genus of free-living organisms that can be found in various habitats. We investigated the physiological characteristics of 15 Acanthamoeba isolates, representing five genotypes (T4, T5, T6, T7, and T11) of both clinical and nonclinical origins. Moreover, in order to evaluate possible alterations from long-term culture, old and fresh isolates were included, and results were compared to a previous study. We found that there is no significant difference in physiological characteristics between genotypes. However, Acanthamoeba strains that had been grown in axenic culture over long periods of time adapted to axenic growth. Overall growth rates under-agarose migration and particularly, temperature tolerance decrease after long-term axenic culture at room temperature. The only trait that remained rather constant was the cytopathic effect.
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Affiliation(s)
- Wilawan Pumidonming
- Department of Medical Parasitology, Institute of Specific Prophylaxis and Tropical Medicine, Medical University of Vienna, Kinderspitalgasse 15, Vienna, 1090, Austria
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15
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Xuan YH, Hong YC, Lee YS, Kang SW, Yu HS, Ahn TI, Chung DI, Kong HH. Acanthamoeba healyi: expressed gene profiles with enhanced virulence after mouse-brain passage. Exp Parasitol 2009; 123:226-30. [PMID: 19651124 DOI: 10.1016/j.exppara.2009.07.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2008] [Revised: 12/26/2008] [Accepted: 07/21/2009] [Indexed: 10/20/2022]
Abstract
The virulence of Acanthamoeba can be attenuated by long-term in vitro cultivation, and can be recovered by serial mouse-brain passage via intranasal inoculation. Recovery is concomitant with changes in expression of virulence-related genes. To investigate the virulence factors of Acanthamoeba, expressed sequence tags (ESTs) from two kinds of cDNA libraries-long-term in vitro cultivated A. healyi (OLD) and three times mouse-brain passaged A. healyi (MBP)-were compared using reciprocal BLAST analysis, eukaryotic orthologous groups (KOG) assignment, and gene annotation. A total of 938 (OLD) and 1033 (MBP) ESTs were sequenced and resulted in the assembling of 718 OLD and 833 MBP unique sequences. Comparison of the KOG analysis revealed a relatively higher percentage of MBP ESTs in genes related to transcription (K group), amino acid transport and metabolism (E group), coenzyme transport and metabolism (H group), and secondary metabolites biosynthesis, transport and metabolism (Q group). However, a higher percentage of unidentified MBP ESTs (57.9%) than OLD ESTs (28.9%) was evidence of the limited understanding of virulence-related factors of Acanthamoeba. Characterization of the genes expressed during brain passage in mice will be useful in clarifying the pathogenesis of granulomatous amoebic encephalitis by Acanthamoeba.
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Affiliation(s)
- Ying-Hua Xuan
- Department of Parasitology, Kyungpook National University, School of Medicine, Taegu 700-422, Republic of Korea
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16
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Koehsler M, Leitsch D, Duchêne M, Nagl M, Walochnik J. Acanthamoeba castellanii : growth on human cell layers reactivates attenuated properties after prolonged axenic culture. FEMS Microbiol Lett 2009; 299:121-7. [PMID: 19732153 PMCID: PMC2810444 DOI: 10.1111/j.1574-6968.2009.01680.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
The free-living, but potentially pathogenic, bacteriovorous amoebae of the genus Acanthamoeba can be easily grown axenically in a laboratory culture. This, however, often leads to considerable losses in virulence, and encystment capacity, and to changes in drug susceptibility. We evaluated potential options for a reactivation of a number of physiological properties, attenuated by prolonged axenic laboratory culture, including encystment potential, protease activity, heat resistance, growth rates and drug susceptibility against N-chlorotaurine (NCT). Toward this end, a strain that had been grown axenically for 10 years was repeatedly passaged on human HEp-2 cell monolayers or treated with 5′-azacytidine (AzaC), a methyltransferase inhibitor, and trichostatin A (TSA), a histone deacetylase inhibitor, in order to uplift epigenetic gene regulation. Culture on human cell monolayers resulted in significantly enhanced encystment potentials and protease activities, and higher susceptibility against NCT, whereas the resistance against heat shock was not altered. Treatment with AzaC/TSA resulted in increased encystment rates and protease activities, indicating the participation of epigenetic mechanisms. However, lowered resistances against heat shock indicate that possible stress responses to AzaC/TSA have to be taken into account. Repeated growth on human cell monolayers appears to be a potential method to reactivate attenuated characteristics in Acanthamoeba.
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Affiliation(s)
- Martina Koehsler
- Department of Medical Parasitology, Clinical Institute of Hygiene and Medical Microbiology, Medical University of Vienna, Kinderspitalgasse 15, Vienna, Austria
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17
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Acanthamoeba strains lose their abilities to encyst synchronously upon prolonged axenic culture. Parasitol Res 2008; 102:1069-72. [PMID: 18247052 DOI: 10.1007/s00436-008-0885-8] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2007] [Accepted: 01/11/2008] [Indexed: 10/22/2022]
Abstract
To evaluate the influence of prolonged axenic culture on the encystment capacity of Acanthamoeba spp., the encystment potential of four closely related Acanthamoeba strains, subcultured axenically for different periods of time, was evaluated comparing five encystment media. Media with more alkaline pH values were slightly more effective; however, the composition of the respective encystment medium had only limited influence on the encystment potential, while a strong correlation of losses in encystment potential and times strains had been cultured axenically was demonstrated. Furthermore, our results indicate that losses in encystment potential occur shortly after transfer into axenic culture to remain constant over many years.
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18
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Abstract
Acanthamoeba is an opportunistic protozoan that is widely distributed in the environment and is well recognized to produce serious human infections, including a blinding keratitis and a fatal encephalitis. This review presents our current understanding of the burden of Acanthamoeba infections on human health, their pathogenesis and pathophysiology, and molecular mechanisms associated with the disease, as well as virulence traits of Acanthamoeba that may be targets for therapeutic interventions and/or the development of preventative measures.
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Affiliation(s)
- Naveed Ahmed Khan
- School of Biological and Chemical Sciences, Birkbeck College, University of London, London, UK.
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19
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Han KL, Lee J, Kim DS, Park SJ, Im KI, Yong TS. Identification of differentially expressed cDNAs in Acanthamoeba culbertsoni after mouse brain passage. THE KOREAN JOURNAL OF PARASITOLOGY 2006; 44:15-20. [PMID: 16514277 PMCID: PMC2532643 DOI: 10.3347/kjp.2006.44.1.15] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2005] [Accepted: 01/20/2006] [Indexed: 11/23/2022]
Abstract
Free-living amoebae of the genus Acanthamoeba are causative agents of granulomatous amebic encephalitis and amebic keratitis. Because the virulence of Acanthamoeba culbertsoni cultured in the laboratory is restored by consecutive brain passages, we examined the genes induced in mouse brain-passaged A. culbertsoni by differential display reverse transcriptase polymerase chain reaction (DDRT-PCR). Enhanced A. culbertsoni virulence was observed during the second mouse brain passage, i.e., infected mouse mortality increased from 5% to 70%. Ten cDNAs induced during mouse brain passage were identified by DDRT-PCR and this was confirmed by northern blot analysis. BlastX searches of these cDNAs indicated the upregulations of genes encoding predictive NADH-dehydrogenase, proteasomal ATPase, and GDP-mannose pyrophosphorylase B, which have previously been reported to be associated with A. culbertsoni virulence factors.
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Affiliation(s)
- Kyu-Lee Han
- Department of Parasitology and Institute of Tropical Medicine, Yonsei University College of Medicine, Seoul, Korea
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20
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Hughes R, Heaselgrave W, Kilvington S. Acanthamoeba polyphaga strain age and method of cyst production influence the observed efficacy of therapeutic agents and contact lens disinfectants. Antimicrob Agents Chemother 2004; 47:3080-4. [PMID: 14506012 PMCID: PMC201123 DOI: 10.1128/aac.47.10.3080-3084.2003] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The effects of age in culture and the type of medium used for induction of Acanthamoeba polyphaga (Ros) cysts on susceptibilities to polyhexamethylene biguanide (PHMB; 3 micro g/ml), chlorhexidine digluconate (30 micro g/ml), myristamidopropyl dimethylamine (20 micro g/ml), H(2)O(2) (3%), and two multipurpose contact lens solutions (MPS-1 and MPS-2, based on 1 micro g of PHMB per ml) were examined. Strain Ros-02 was cryopreserved on isolation in 1991, while strain Ros-91 had been in continuous axenic culture. Significant differences in susceptibilities to the disinfectants were found depending on the medium used for cyst preparation and the age of the test strain, with Ros-02 generally being more resistant. For example, the killing of Ros-91 cysts produced from an axenic culture of trophozoites in the presence of 50 mM MgCl(2) by MPS-2 was 4 logs, but the killing of Ros-02 by MPS-2 was only 2 logs (P < 0.05) and killing of both strains with cysts obtained from monoxenic cultures with Escherichia coli was only 1 log (P < 0.001). Assays repeated with different batches of the various cyst types gave consistent results. A batch of Ros-91 cysts stored at 4 degrees C and tested over an 8-week period with MPS-1 showed progressively increasing susceptibility to disinfection, although there was no loss of viability during storage (P < 0.01). These observations have important implications for the standardization and interpretation of Acanthamoeba disinfectant and therapeutic agent testing.
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Affiliation(s)
- Reanne Hughes
- Department of Microbiology and Immunology, University of Leicester, Leicester LE1 9HN, United Kingdom.
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21
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Marciano-Cabral F, Han K, Powell E, Ferguson T, Cabral G. Interaction of an Acanthamoeba Human Isolate Harboring Bacteria with Murine Peritoneal Macrophages1. J Eukaryot Microbiol 2003; 50 Suppl:516-9. [PMID: 14736148 DOI: 10.1111/j.1550-7408.2003.tb00615.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- Francine Marciano-Cabral
- Department of Microbiology and Immunology, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA, USA.
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22
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Kinnear FB. Cytopathogenicity of acanthamoeba, vahlkampfia and hartmannella: quantative & qualitative in vitro studies on keratocytes. J Infect 2003; 46:228-37. [PMID: 12799148 DOI: 10.1053/jinf.2002.1116] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVES To compare the cytopathogenicity of Vahlkampfia and Hartmannella clinical isolates with a type culture of Acanthamoeba castellanii. METHODS The cytopathic effect produced during 24 h co-incubation with cultured keratocytes was assessed at set time intervals. Formal quantative studies involved image analysis of the area of cells remaining after 6 h. The mechanism of cytopathogenicity was elucidated using time-lapse video, light and scanning electron microscopy. The ability to produce cell damage in the absence of physical contact was studied using the transwell apparatus. The role of apotosis was also investigated. RESULTS All three isolates produced near destruction of the keratocyte monolayer within 24 h, although initial cell destruction was more rapid with Acanthamoeba. For all three genera, the mechanism of cell damage involved physical attack and trogocytosis: cytopathic products were also implicated as cell damage was produced in the absence of physical contact, but apoptosis was not demonstrated. CONCLUSIONS While the results do not prove that Vahlkampfia and Hartmannella are pathogens, they provide important evidence supporting the thesis that they cause keratitis by demonstrating that their ability to produce a cytopathic effect on keratocytes in vitro is similar in magnitude and mechanism to that of the known pathogen Acanthamoeba castellanii. The mechanisms by which small free-living amoebae produce cell damage is poorly understood. The ability of genera of amoebae other than Acanthamoeba to produce corneal infection remains controversial. In this study, the cytopathogenicity of Vahlkampfia and Hartmannella isolated from a case human keratitis are compared both quantitatively and qualitatively with that to the known pathogen Acanthamoeba castellanii. The results suggest that representatives of each of the 3 genera produce a similar degree of cytopathic effect on keratocytes after 24h of co-incubation and that a combination of physical and chemical factors are responsible.
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Affiliation(s)
- F B Kinnear
- Department of Ophthalmic Pathology, University of Glasgow, Glasgow, G12 6NT, Scotland.
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23
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Abstract
Acanthamoeba spp. are free-living amebae that inhabit a variety of air, soil, and water environments. However, these amebae can also act as opportunistic as well as nonopportunistic pathogens. They are the causative agents of granulomatous amebic encephalitis and amebic keratitis and have been associated with cutaneous lesions and sinusitis. Immuno compromised individuals, including AIDS patients, are particularly susceptible to infections with Acanthamoeba. The immune defense mechanisms that operate against Acanthamoeba have not been well characterized, but it has been proposed that both innate and acquired immunity play a role. The ameba's life cycle includes an active feeding trophozoite stage and a dormant cyst stage. Trophozoites feed on bacteria, yeast, and algae. However, both trophozoites and cysts can retain viable bacteria and may serve as reservoirs for bacteria with human pathogenic potential. Diagnosis of infection includes direct microscopy of wet mounts of cerebrospinal fluid or stained smears of cerebrospinal fluid sediment, light or electron microscopy of tissues, in vitro cultivation of Acanthamoeba, and histological assessment of frozen or paraffin-embedded sections of brain or cutaneous lesion biopsy material. Immunocytochemistry, chemifluorescent dye staining, PCR, and analysis of DNA sequence variation also have been employed for laboratory diagnosis. Treatment of Acanthamoeba infections has met with mixed results. However, chlorhexidine gluconate, alone or in combination with propamidene isethionate, is effective in some patients. Furthermore, effective treatment is complicated since patients may present with underlying disease and Acanthamoeba infection may not be recognized. Since an increase in the number of cases of Acanthamoeba infections has occurred worldwide, these protozoa have become increasingly important as agents of human disease.
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Affiliation(s)
- Francine Marciano-Cabral
- Department of Microbiology and Immunology, Virginia Commonwealth University, Richmond, Virginia 23298-0678, USA.
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25
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Im KI, Park KM, Yong TS, Hong YP, Kim TE. Upregulated expression of the cDNA fragment possibly related to the virulence of Acanthamoeba culbertsoni. THE KOREAN JOURNAL OF PARASITOLOGY 1999; 37:257-63. [PMID: 10634042 PMCID: PMC2733203 DOI: 10.3347/kjp.1999.37.4.257] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Identification of the genes responsible for the recovery of virulence in brain-passaged Acanthamoeba culbertsoni was attempted via mRNA differential display-polymerase chain reaction (mRNA DD-PCR) analysis. In order to identify the regulatory changes in transcription of the virulence related genes by the brain passages, mRNA DD-PCR was performed which enabled the display of differentially transcribed mRNAs after the brain passages. Through mRNA DD-PCR analysis. 96 brain-passaged amoeba specific amplicons were observed and were screened to identify the amplicons that failed to amplify in the non-brain-passaged amoeba mRNAs. Out of the 96 brain-passaged amoeba specific amplicons, 12 turned out to be amplified only from the brain-passaged amoeba mRNAs by DNA slot blot hybridization. The clone, A289C, amplified with an arbitrary primer of UBC #289 and the oligo dT11-C primer, revealed the highest homology (49.8%) to the amino acid sequences of UPD-galactose lipid transferase of Erwinia amylovora, which is known to act as an important virulence factor. The deduced amino acid sequences of an insert DNA in clone A289C were also revealed to be similar to cpsD, which is the essential gene for the expression of type III capsule in group B streptococcus. Upregulated expression of clone A289C was verified by RNA slot blot hybridization. Similar hydrophobicity values were also observed between A289C (at residues 47-66) and the AmsG gene of E. amylovora (at residues 286-305: transmembrane domains). This result suggested that the insert of clone A289C might play the same function as galactosyl transferase controlled by the AmsG gene in E. amylovora.
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Affiliation(s)
- K I Im
- Department of Parasitology, Yonsei University College of Medicine, Seoul, Korea
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26
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Im KI, Shin HJ, Seo DW, Jeon SH, Kim TE. Pathogenicity of Korean isolates of Acanthamoeba by observing the experimental infection and zymodemes of five isoenzymes. THE KOREAN JOURNAL OF PARASITOLOGY 1999; 37:85-92. [PMID: 10388266 PMCID: PMC2733061 DOI: 10.3347/kjp.1999.37.2.85] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
To determine the pathogenicity of Acanthamoeba spp. isolated in Korea and to develop a isoenzymatic maker, the mortality rate of infected mice, in vitro cytotoxicity against target cells and isoenzyme band patterns were observed. Five isolates of Acanthamoeba spp. (YM-2, YM-3, YM-4, YM-5, and YM-7) were used in this study as well as three reference Acanthamoeba spp. (A. culbertsoni, A. hatchetti, and A. royreba). According to the mortality rate of infected mice, Korean isolates could be categorized into three groups high virulent (YM-4), low virulent (YM-2, YM-5, YM-7) and the nonpathogenic group (YM-3). In addition, the virulence of Acanthamoeba spp. was enhanced by brain passage in mice. In the cytotoxicity assay against chinese hamster ovary cells, especially, the cytotoxicity of brain-passaged amoebae was relatively higher than the long-term cultivated ones. The zymodeme patterns of glucose-6-phosphate dehydrogenase (G6PD), malate dehydrogenase (MDH), hexokinase (HK), glutamate oxaloacetate transaminase (GOT) and malic enzyme (ME) of Acanthamoeba spp. were different among each isolate, and also between long-term cultured amoebae and brain passaged ones. In spite of the polymorphic zymodemes, a slow band of G6PD and HK, and an intermediate band of MDH were only observed in pathogenic Acanthamoeba spp., which should be used as isoenzymatic makers.
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Affiliation(s)
- K I Im
- Department of Parasitology, Yonsei University College of Medicine, Seoul, Korea
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