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Shih KY, Chang YT, Wang YJ, Huang JM. Ouabain, ATPase inhibitor, potentially enhances the effect of polyhexamethylene biguanide on Acanthamoeba castellanii. Int J Parasitol Drugs Drug Resist 2024; 25:100550. [PMID: 38821038 DOI: 10.1016/j.ijpddr.2024.100550] [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: 04/05/2024] [Revised: 05/16/2024] [Accepted: 05/21/2024] [Indexed: 06/02/2024]
Abstract
Acanthamoeba, a free-living amoeba, is commonly found in various natural environments, such as rivers and soil, as well as in public baths, swimming pools, and sewers. Acanthamoeba can cause severe illness such as granulomatous amoebic encephalitis and Acanthamoeba keratitis (AK) in humans. AK, the most recognized disease, can cause permanent visual impairment or blindness by affecting the cornea. AK commonly affects contact lens wearers who neglect proper cleaning habits. The symptoms of AK include epithelial and stromal destruction, corneal infiltrate, and intense ocular pain, occasionally necessitating surgical removal of the entire eyeball. Current AK treatment involves the hourly application of eye drops containing polyhexamethylene biocide (PHMB). However, studies have revealed their ineffectiveness against drug-resistant strains. Acanthamoeba can form cysts as a survival mechanism in adverse environments, though the exact mechanism remains unknown. Our experiments revealed that sodium P-type ATPase (ACA1_065450) is closely linked to encystation. In addition, various encystation buffers, such as MgCl2 or NaCl, induced the expression of P-type ATPase. Furthermore, we used ouabain, an ATPase inhibitor, to inhibit the Na+/K+ ion pump, consequently decreasing the encystation rate of Acanthamoeba. Our primary objective is to develop an advanced treatment for AK. We anticipate that the combination of ouabain and PHMB may serve as an effective therapeutic approach against AK in the future.
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Affiliation(s)
- Kuang-Yi Shih
- Department of Life Science, College of Life Sciences and Medicine, National Tsing Hua University, Hsinchu, Taiwan.
| | - Yao-Tsung Chang
- Department of Biochemistry and Molecular Biology, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
| | - Yu-Jen Wang
- Department of Parasitology, School of Medicine, China Medical University, Taichung, Taiwan.
| | - Jian-Ming Huang
- School of Medicine, College of Life Sciences and Medicine, National Tsing Hua University, Hsinchu, Taiwan; Department of Medical Science, College of Life Sciences and Medicine, National Tsing Hua University, Hsinchu, Taiwan; Institute of Molecular and Cellular Biology, College of Life Sciences and Medicine, National Tsing Hua University, Hsinchu, Taiwan.
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Sarink MJ, Koelewijn R, Stelma F, Kortbeek T, van Lieshout L, Smit PW, Tielens AGM, van Hellemond JJ. An International External Quality Assessment Scheme to Assess the Diagnostic Performance of Polymerase Chain Reaction Detection of Acanthamoeba Keratitis. Cornea 2023; 42:1027-1033. [PMID: 37155347 PMCID: PMC10306335 DOI: 10.1097/ico.0000000000003275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2022] [Revised: 02/04/2023] [Accepted: 02/16/2023] [Indexed: 05/10/2023]
Abstract
PURPOSE The purpose of this study was to assess the variation in methods and to determine whether an External Quality Assessment Scheme (EQAS) for polymerase chain reaction (PCR) detection of Acanthamoeba keratitis is valuable for the diagnostic process. METHODS A multicenter EQAS was introduced, covering 16 diagnostic laboratories. Using Acanthamoeba castellanii ATCC strain 30010, 3 sets of samples were prepared, containing different amounts of DNA, cysts, or trophozoites. Samples were masked and sent to the participants with instructions for use and a questionnaire concerning the applied methodologies. Special attention in this questionnaire was given to the used pretreatment methods to assess existing variations in these procedures. RESULTS A large variation in the methodologies and substantial differences in the diagnostic performance were found between participants. In contrast to the DNA samples where all participants had a perfect score, several false negative results were reported for the samples containing cysts or trophozoites. Only 9 participants had an optimal score, whereas one participant reported all samples as negative, one participant reported failures due to inhibition, and the other 5 reported in total 7 false negative results. A clear correlation was noticed between the PCR detection rate and the number of cysts or trophozoites in the sample. CONCLUSIONS The results indicate that a pretreatment procedure can be a risky step in PCR-based detections of Acanthamoeba , but it improves the sensitivity and reliability, especially of samples containing cysts. Therefore, participation in an EQAS is informative for routine diagnostic laboratories and can assist in improving the laboratory procedures used for the diagnosis of Acanthamoeba keratitis.
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Affiliation(s)
- Maarten J. Sarink
- Department of Medical Microbiology and Infectious Diseases, Erasmus MC University Medical Center, Rotterdam, the Netherlands
| | - Rob Koelewijn
- Department of Medical Microbiology and Infectious Diseases, Erasmus MC University Medical Center, Rotterdam, the Netherlands
| | - Foekje Stelma
- Department of Medical Microbiology, Radboudumc Nijmegen, the Netherlands
| | - Titia Kortbeek
- National Institute of Public Health and the Environment, RIVM, Bilthoven, the Netherlands
| | - Lisette van Lieshout
- Department of Parasitology, Leiden University Medical Centre, Leiden, the Netherlands; and
| | - Pieter W. Smit
- Department of Medical Microbiology, Molecular Diagnostics Unit, Maasstad Hospital, Rotterdam, the Netherlands
| | - Aloysius G. M. Tielens
- Department of Medical Microbiology and Infectious Diseases, Erasmus MC University Medical Center, Rotterdam, the Netherlands
| | - Jaap J. van Hellemond
- Department of Medical Microbiology and Infectious Diseases, Erasmus MC University Medical Center, Rotterdam, the Netherlands
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Sohn HJ, Kim JH, Kim K, Park S, Shin HJ. De Novo Transcriptome Profiling of Naegleria fowleri Trophozoites and Cysts via RNA Sequencing. Pathogens 2023; 12:pathogens12020174. [PMID: 36839446 PMCID: PMC9959186 DOI: 10.3390/pathogens12020174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 01/18/2023] [Accepted: 01/20/2023] [Indexed: 01/24/2023] Open
Abstract
Naegleria fowleri is a pathogenic free-living amoeba, commonly found around the world in warm, fresh water and soil. N. fowleri trophozoites can infect humans by entering the brain through the nose and causing usually fatal primary amebic meningoencephalitis (PAM). Trophozoites can encyst to survive under unfavorable conditions such as cold temperature, starvation, and desiccation. Recent technological advances in genomics and bioinformatics have provided unique opportunities for the identification and pre-validation of pathogen-related and environmental resistance through improved understanding of the biology of pathogenic N. fowleri trophozoites and cysts at a molecular level. However, genomic and transcriptomic data on differential expression genes (DEGs) between trophozoites and cysts of N. fowleri are very limited. Here, we report transcriptome Illumina RNA sequencing (RNA-seq) for N. fowleri trophozoites and cysts and de novo transcriptome assembly. RNA-seq libraries were generated from RNA extracted from N. fowleri sampled from cysts, and a reference transcriptome was generated through the assembly of trophozoite data. In the database, the assembly procedure resulted in 42,220 contigs with a mean length of 11,254 nucleotides and a C+G content of 37.21%. RNA sequencing showed that 146 genes in cysts of N. fowleri indicated 2-fold upregulation in comparison with trophozoites of N. fowleri, and 163 genes were downregulated; these genes were found to participate in the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway. The KEGG pathway included metabolic (131 sequences) and genetic information processing (66 sequences), cellular processing (43 sequences), environmental information processing (22 sequences), and organismal system (20 sequences) pathways. On the other hand, an analysis of 11,254 sequences via the Gene Ontology database showed that their annotations contained 1069 biological processes including the cellular process (228 sequences) and metabolic process (214 sequences); 923 cellular components including cells (240 sequences) and cell parts (225 sequences); and 415 molecular functions including catalytic activities (195 sequences) and binding processes (186 sequences). Differential expression levels increased in cysts of N. fowleri compared to trophozoites of N. fowleri, which were mainly categorized as serine/threonine protease, kinase, and lipid metabolism-related proteins. These results may provide new insights into pathogen-related genes or environment-resistant genes in the pathogenesis of N. fowleri.
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Affiliation(s)
- Hae-Jin Sohn
- Department of Microbiology, Ajou University School of Medicine, Suwon 16499, Republic of Korea
- Department of Biomedical Science, Graduate School of Ajou University, Suwon 16499, Republic of Korea
| | - Jong-Hyun Kim
- Institute of Animal Medicine, College of Veterinary Medicine, Gyeongsang National University, Jinju 52828, Republic of Korea
| | - Kyongmin Kim
- Department of Microbiology, Ajou University School of Medicine, Suwon 16499, Republic of Korea
- Department of Biomedical Science, Graduate School of Ajou University, Suwon 16499, Republic of Korea
| | - Sun Park
- Department of Microbiology, Ajou University School of Medicine, Suwon 16499, Republic of Korea
- Department of Biomedical Science, Graduate School of Ajou University, Suwon 16499, Republic of Korea
| | - Ho-Joon Shin
- Department of Microbiology, Ajou University School of Medicine, Suwon 16499, Republic of Korea
- Department of Biomedical Science, Graduate School of Ajou University, Suwon 16499, Republic of Korea
- Correspondence:
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Rased NM, Johari SATT, Zakeri HA, Ma NL, Razali SA, Hashim F. Combinatorial treatment with β-glucanase enzyme and chlorhexidine induces cysticidal effects in Acanthamoeba cyst. Parasitol Res 2022; 121:3105-3119. [DOI: 10.1007/s00436-022-07650-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2021] [Accepted: 08/29/2022] [Indexed: 11/24/2022]
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Akbar N, Kaman WE, Sarink M, Nazmi K, Bikker FJ, Khan NA, Siddiqui R. Novel Antiamoebic Tyrocidine-Derived Peptide against Brain-Eating Amoebae. ACS OMEGA 2022; 7:28797-28805. [PMID: 36033708 PMCID: PMC9404165 DOI: 10.1021/acsomega.2c01614] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Accepted: 07/28/2022] [Indexed: 06/15/2023]
Abstract
Acanthamoeba castellanii (A. castellanii) can cause Acanthamoeba keratitis, a sight-threatening infection, as well as a fatal brain infection termed granulomatous amoebic encephalitis, mostly in immunocompromised individuals. In contrast, Naegleria fowleri (N. fowleri) causes a deadly infection involving the central nervous system, recognized as primary amoebic encephalitis, mainly in individuals partaking in recreational water activities or those with nasal exposure to contaminated water. Worryingly, mortality rates due to these infections are more than 90%, suggesting the need to find alternative therapies. In this study, antiamoebic activity of a peptide based on the structure of the antibiotic tyrocidine was evaluated against A. castellanii and N. fowleri. The tyrocidine-derived peptide displayed significant amoebicidal efficacy against A. castellanii and N. fowleri. At 250 μg/mL, the peptide drastically reduced amoebae viability up to 13% and 21% after 2 h of incubation against N. fowleri and A. castellanii., whereas, after 24 h of incubation, the peptide showed 86% and 94% amoebicidal activity against A. castellanii and N. fowleri. Furthermore, amoebae pretreated with 100 μg/mL peptide inhibited 35% and 53% A. castellanii and N. fowleri, while, at 250 μg/mL, 84% and 94% A. castellanii and N. fowleri failed to adhere to human cells. Amoeba-mediated cell cytopathogenicity assays revealed 31% and 42% inhibition at 100 μg/mL, while at 250 μg/mL 75% and 86% A. castellanii and N. fowleri were inhibited. Assays revealed inhibition of encystation in both A. castellanii (58% and 93%) and N. fowleri (73% and 97%) at concentrations of 100 and 250 μg/mL respectively. Importantly, tyrocidine-derived peptide depicted minimal cytotoxicity to human cells and, thus, may be a potential candidate in the rational development of a treatment regimen against free-living amoebae infections. Future studies are necessary to elucidate the in vivo effects of tyrocidine-derived peptide against these and other pathogenic amoebae of importance.
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Affiliation(s)
- Noor Akbar
- College
of Arts and Sciences, American University
of Sharjah, University
City, Sharjah 26666, United Arab Emirates
| | - Wendy E. Kaman
- Department
of Oral Biochemistry, Academic Centre for Dentistry Amsterdam, University of Amsterdam and VU University Amsterdam, 1081 LA Amsterdam, The Netherlands
| | - Maarten Sarink
- Erasmus MC, University Medical Center
Rotterdam, Department
of Medical Microbiology and Infectious Diseases, Wytemaweg 80, 3015
CE Rotterdam, The Netherlands
| | - Kamran Nazmi
- Department
of Oral Biochemistry, Academic Centre for Dentistry Amsterdam, University of Amsterdam and VU University Amsterdam, 1081 LA Amsterdam, The Netherlands
| | - Floris J. Bikker
- Department
of Oral Biochemistry, Academic Centre for Dentistry Amsterdam, University of Amsterdam and VU University Amsterdam, 1081 LA Amsterdam, The Netherlands
| | - Naveed Ahmed Khan
- Department
of Clinical Sciences, College of Medicine, University of Sharjah, University
City, Sharjah 27272, Unites Arab Emirates
| | - Ruqaiyyah Siddiqui
- College
of Arts and Sciences, American University
of Sharjah, University
City, Sharjah 26666, United Arab Emirates
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Boonhok R, Sangkanu S, Phumjan S, Jongboonjua R, Sangnopparat N, Kwankaew P, Tedasen A, Lim CL, Pereira MDL, Rahmatullah M, Wilairatana P, Wiart C, Dolma KG, Paul AK, Gupta M, Nissapatorn V. Curcumin effect on Acanthamoeba triangularis encystation under nutrient starvation. PeerJ 2022; 10:e13657. [PMID: 35811814 PMCID: PMC9261923 DOI: 10.7717/peerj.13657] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Accepted: 06/09/2022] [Indexed: 01/17/2023] Open
Abstract
Background Curcumin is an active compound derived from turmeric, Curcuma longa, and is known for its benefits to human health. The amoebicidal activity of curcumin against Acanthamoeba triangularis was recently discovered. However, a physiological change of intracellular pathways related to A. triangularis encystation mechanism, including autophagy in the surviving amoeba after curcumin treatment, has never been reported. This study aims to investigate the effect of curcumin on the survival of A. triangularis under nutrient starvation and nutrient-rich condition, as well as to evaluate the A. triangularis encystation and a physiological change of Acanthamoeba autophagy at the mRNA level. Methods In this study, A. triangularis amoebas were treated with a sublethal dose of curcumin under nutrient starvation and nutrient-rich condition and the surviving amoebas was investigated. Cysts formation and vacuolization were examined by microscopy and transcriptional expression of autophagy-related genes and other encystation-related genes were evaluated by real-time PCR. Results A. triangularis cysts were formed under nutrient starvation. However, in the presence of the autophagy inhibitor, 3-methyladenine (3-MA), the percentage of cysts was significantly reduced. Interestingly, in the presence of curcumin, most of the parasites remained in the trophozoite stage in both the starvation and nutrient-rich condition. In vacuolization analysis, the percentage of amoebas with enlarged vacuole was increased upon starvation. However, the percentage was significantly declined in the presence of curcumin and 3-MA. Molecular analysis of A. triangularis autophagy-related (ATG) genes showed that the mRNA expression of the ATG genes, ATG3, ATG8b, ATG12, ATG16, under the starvation with curcumin was at a basal level along the treatment. The results were similar to those of the curcumin-treated amoebas under a nutrient-rich condition, except AcATG16 which increased later. On the other hand, mRNA expression of encystation-related genes, cellulose synthase and serine proteinase, remained unchanged during the first 18 h, but significantly increased at 24 h post treatment. Conclusion Curcumin inhibits cyst formation in surviving trophozoites, which may result from its effect on mRNA expression of key Acanthamoeba ATG-related genes. However, further investigation into the mechanism of curcumin in A. triangularis trophozoites arrest and its association with autophagy or other encystation-related pathways is needed to support the future use of curcumin.
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Affiliation(s)
- Rachasak Boonhok
- Department of Medical Technology, School of Allied Health Sciences, and Research Excellence Center for Innovation and Health Products (RECIHP), Walailak University, Thai Buri, Nakhon Si Thammarat, Thailand
| | - Suthinee Sangkanu
- School of Allied Health Sciences, Southeast Asia Water Team (SEA Water Team) and World Union for Herbal Drug Discovery (WUHeDD), and Research Excellence Center for Innovation and Health Products (RECIHP), Walailak University, Thai Buri, Nakhon Si Thammarat, Thailand
| | - Suganya Phumjan
- Department of Medical Technology, School of Allied Health Sciences, and Research Excellence Center for Innovation and Health Products (RECIHP), Walailak University, Thai Buri, Nakhon Si Thammarat, Thailand
| | - Ramita Jongboonjua
- Department of Medical Technology, School of Allied Health Sciences, and Research Excellence Center for Innovation and Health Products (RECIHP), Walailak University, Thai Buri, Nakhon Si Thammarat, Thailand
| | - Nawarat Sangnopparat
- Department of Medical Technology, School of Allied Health Sciences, and Research Excellence Center for Innovation and Health Products (RECIHP), Walailak University, Thai Buri, Nakhon Si Thammarat, Thailand
| | - Pattamaporn Kwankaew
- Department of Medical Technology, School of Allied Health Sciences, and Research Excellence Center for Innovation and Health Products (RECIHP), Walailak University, Thai Buri, Nakhon Si Thammarat, Thailand
| | - Aman Tedasen
- Department of Medical Technology, School of Allied Health Sciences, and Research Excellence Center for Innovation and Health Products (RECIHP), Walailak University, Thai Buri, Nakhon Si Thammarat, Thailand
| | - Chooi Ling Lim
- Division of Applied Biomedical Science and Biotechnology, School of Health Sciences, International Medical University, Kuala Lumpur, Malaysia
| | - Maria de Lourdes Pereira
- CICECO-Aveiro Institute of Materials and Department of Medical Sciences, University of Aveiro, Aveiro, Portugal
| | - Mohammed Rahmatullah
- Department of Biotechnology and Genetic Engineering, University of Development Alternative, Dhaka, Bangladesh
| | - Polrat Wilairatana
- Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Rachathewee, Bangkok, Thailand
| | - Christophe Wiart
- The Institute for Tropical Biology and Conservation, Universiti Malaysia Sabah, Kota Kinabalu, Sabah, Malaysia
| | - Karma G. Dolma
- Department of Microbiology, Sikkim Manipal Institute of Medical Sciences, Sikkim, India
| | - Alok K. Paul
- School of Pharmacy and Pharmacology, University of Tasmania, Hobart, Tasmania, Australia
| | - Madhu Gupta
- Department of Pharmaceutics, Delhi Pharmaceutical Sciences and Research University, New Delhi, India
| | - Veeranoot Nissapatorn
- School of Allied Health Sciences, Southeast Asia Water Team (SEA Water Team) and World Union for Herbal Drug Discovery (WUHeDD), and Research Excellence Center for Innovation and Health Products (RECIHP), Walailak University, Thai Buri, Nakhon Si Thammarat, Thailand
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Shing B, Balen M, Fenical W, Debnath A. Development of a Machine Learning-Based Cysticidal Assay and Identification of an Amebicidal and Cysticidal Marine Microbial Metabolite against Acanthamoeba. Microbiol Spectr 2022; 10:e0007722. [PMID: 35467370 PMCID: PMC9241814 DOI: 10.1128/spectrum.00077-22] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Accepted: 04/10/2022] [Indexed: 11/20/2022] Open
Abstract
Traditional cysticidal assays for Acanthamoeba species revolve around treating cysts with compounds and manually observing the culture for evidence of excystation. This method is time-consuming, labor-intensive, and low throughput. We adapted and trained a YOLOv3 machine learning, object detection neural network to recognize Acanthamoeba castellanii trophozoites and cysts in microscopy images to develop an automated cysticidal assay. This trained neural network was used to count trophozoites in wells treated with compounds of interest to determine if a compound treatment was cysticidal. We validated this new assay with known cysticidal and noncysticidal compounds. In addition, we undertook a large-scale bioluminescence-based screen of 9,286 structurally unique marine microbial metabolite fractions against the trophozoites of A. castellanii and identified 29 trophocidal hits. These hits were then subjected to this machine learning-based automated cysticidal assay. One marine microbial metabolite fraction was identified as both trophocidal and cysticidal. IMPORTANCE The free-living Acanthamoeba can exist as a trophozoite or cyst and both stages can cause painful blinding keratitis. Infection recurrence occurs in approximately 10% of cases due to the lack of efficient drugs that can kill both trophozoites and cysts. Therefore, the discovery of therapeutics that are effective against both stages is a critical unmet need to avert blindness. Current efforts to identify new anti-Acanthamoeba compounds rely primarily upon assays that target the trophozoite stage of the parasite. We adapted and trained a machine learning, object detection neural network to recognize Acanthamoeba trophozoites and cysts in microscopy images. Our machine learning-based cysticidal assay improved throughput, demonstrated high specificity, and had an exquisite ability to identify noncysticidal compounds. We combined this cysticidal assay with our bioluminescence-based trophocidal assay to screen about 9,000 structurally unique marine microbial metabolites against A. castellanii. Our screen identified a marine metabolite that was both trophocidal and cysticidal.
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Affiliation(s)
- Brian Shing
- Center for Discovery and Innovation in Parasitic Diseases, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, California, USA
| | - Mina Balen
- Center for Discovery and Innovation in Parasitic Diseases, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, California, USA
| | - William Fenical
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San Diego, La Jolla, California, USA
| | - Anjan Debnath
- Center for Discovery and Innovation in Parasitic Diseases, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, California, USA
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Evaluation of Amebicidal and Cysticidal Activities of Antifungal Drug Isavuconazonium Sulfate against Acanthamoeba T4 Strains. Pharmaceuticals (Basel) 2021; 14:ph14121294. [PMID: 34959694 PMCID: PMC8707217 DOI: 10.3390/ph14121294] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 12/08/2021] [Accepted: 12/08/2021] [Indexed: 11/30/2022] Open
Abstract
Acanthamoeba species of amebae are often associated with Acanthamoeba keratitis, a severe corneal infection. Isavuconazonium sulfate is an FDA-approved drug for the treatment of invasive aspergillosis and mucormycosis. This prodrug is metabolized into the active isavuconazole moiety. Isavuconazole was previously identified to have amebicidal and cysticidal activity against Acanthamoeba T4 strains, but the activity of its prodrug, isavuconazonium sulfate, against trophozoites and cysts remains unknown. Since it is not known if isavuconazonium can be metabolized into isavuconazole in the human eye, we evaluated the activities of isavuconazonium sulfate against trophozoites and cysts of three T4 genotype strains of Acanthamoeba. Isavuconazonium displayed amebicidal activity at nanomolar concentrations as low as 1.4 nM and prevented excystation of cysts at concentrations as low as 136 μM. We also investigated the cysticidal activity of isavuconazonium sulfate in combination with a currently used amebicidal drug polyhexamethylene biguanide (PHMB). Although combination of isavuconazonium with PHMB did not elicit an obvious synergistic cysticidal activity, the combination did not cause an antagonistic effect on the cysts of Acanthamoeba T4 strains. Collectively, these findings suggest isavuconazonium retains potency against Acanthamoeba T4 strains and could be adapted for Acanthamoeba keratitis treatment.
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Güémez A, García E. Primary Amoebic Meningoencephalitis by Naegleria fowleri: Pathogenesis and Treatments. Biomolecules 2021; 11:biom11091320. [PMID: 34572533 PMCID: PMC8469197 DOI: 10.3390/biom11091320] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2021] [Revised: 08/20/2021] [Accepted: 08/25/2021] [Indexed: 12/29/2022] Open
Abstract
Naegleria fowleri is a free-living amoeba (FLA) that is commonly known as the "brain-eating amoeba." This parasite can invade the central nervous system (CNS), causing an acute and fulminating infection known as primary amoebic meningoencephalitis (PAM). Even though PAM is characterized by low morbidity, it has shown a mortality rate of 98%, usually causing death in less than two weeks after the initial exposure. This review summarizes the most recent information about N. fowleri, its pathogenic molecular mechanisms, and the neuropathological processes implicated. Additionally, this review includes the main therapeutic strategies described in case reports and preclinical studies, including the possible use of immunomodulatory agents to decrease neurological damage.
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Inhibitory effect of host ocular microenvironmental factors on chlorhexidine digluconate activity. Antimicrob Agents Chemother 2021; 65:AAC.02066-20. [PMID: 33685899 PMCID: PMC8092908 DOI: 10.1128/aac.02066-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Acanthamoeba spp. are free-living protozoan that cause a serious human eye disease called Acanthamoeba keratitis (AK). Several new and effective medical therapy for AK patients remains highly debated and therefore, CHG is still considered one of the first lines of treatment for AK patients. We hypothesized that ocular microenvironmental factors are responsible for Acanthamoeba drug resistance and clinical AK treatment failure. To investigate the influence of the ocular surface on CHG treatment, we tested the effect of several ocular elements on the anti-amoeba activity of CHG. The suspected inhibitory elements, including mucin, albumin, human and amoeba cell lysates, live and heat-killed bacteria, and cornea, were added to the amoebicidal activity platform, where amoeba was incubated with CHG at varying concentrations. Mucin showed a significant inhibitory effect on CHG activity against Acanthamoeba castellanii In contrast, albumin did not affect CHG treatment. Furthermore, human and amoeba cell lysates as well as live and heat-killed bacterial suspensions also significantly inhibited CHG activity. Additionally, we found that pig corneas also reduced CHG activity. In contrast, dry eye drops and their major component, propylene glycol, which is commonly used as eyewash material, did not have an impact on CHG activity. Our results demonstrate the effect of ocular microenvironmental factors on CHG activity and suggest that these factors may play a role in the development of amoeba resistance to CHG and treatment failure.
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A Novel Cysteine Protease Inhibitor of Naegleria fowleri That Is Specifically Expressed during Encystation and at Mature Cysts. Pathogens 2021; 10:pathogens10040388. [PMID: 33804993 PMCID: PMC8063937 DOI: 10.3390/pathogens10040388] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 03/21/2021] [Accepted: 03/22/2021] [Indexed: 11/26/2022] Open
Abstract
Naegleria fowleri is a free-living amoeba that is ubiquitous in diverse natural environments. It causes a fatal brain infection in humans known as primary amoebic meningoencephalitis. Despite the medical importance of the parasitic disease, there is a great lack of knowledge about the biology and pathogenicity of N. fowleri. In this study, we identified and characterized a novel cysteine protease inhibitor of N. fowleri (NfCPI). NfCPI is a typical cysteine protease inhibitor belonging to the cystatin family with a Gln-Val-Val-Ala-Gly (QVVAG) motif, a characteristic motif conserved in the cystatin family of proteins. Bacterially expressed recombinant NfCPI has a dimeric structure and exhibits inhibitory activity against several cysteine proteases including cathespin Bs of N. fowleri at a broad range of pH values. Expression profiles of nfcpi revealed that the gene was highly expressed during encystation and cyst of the amoeba. Western blot and immunofluorescence assays also support its high level of expression in cysts. These findings collectively suggest that NfCPI may play a critical role in encystation or cyst formation of N. fowleri by regulating cysteine proteases that may mediate encystation or mature cyst formation of the amoeba. More comprehensive studies to investigate the roles of NfCPI in encystation and its target proteases are necessary to elucidate the regulatory mechanism and the biological significance of NfCPI.
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Establishment of an Acanthamoeba keratitis mouse model confirmed by amoebic DNA amplification. Sci Rep 2021; 11:4183. [PMID: 33603075 PMCID: PMC7892866 DOI: 10.1038/s41598-021-83738-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Accepted: 02/04/2021] [Indexed: 11/08/2022] Open
Abstract
Acanthamoeba castellanii, the causative agent of Acanthamoeba keratitis (AK), occurs mainly in contact lens users with poor eye hygiene. The findings of many in vitro studies of AK, as well as the testing of therapeutic drugs, need validation in in vivo experiments. BALB/c mice were used in this study to establish in vivo AK model. A. castellanii cell suspensions (equal mixtures of trophozoites and cysts) were loaded onto 2-mm contact lens pieces and inserted into mouse eyes that were scratched using an ophthalmic surgical blade under anesthesia and the eyelids of the mice were sutured. The AK signs were grossly observed and PCR was performed using P-FLA primers to amplify the Acanthamoeba 18S-rRNA gene from mouse ocular tissue. The experimental AK mouse model was characterized by typical hazy blurring and melting of the mouse cornea established on day 1 post-inoculation. AK was induced with at least 0.3 × 105 A. castellanii cells (optimal number, 5 × 104), and the infection persisted for two months. The PCR products amplified from the extracted mouse eye DNA confirmed the development of Acanthamoeba-induced keratitis during the infection periods. In conclusion, the present AK mouse model may serve as an important in vivo model for the development of various therapeutic drugs against AK.
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13
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Tsai CM, Chen JW, Lin WC. Effects of Acanthamoeba castellanii on the dissolved oxygen and the microbial community under the experimental aquatic model. Exp Parasitol 2020; 218:107985. [PMID: 32918877 DOI: 10.1016/j.exppara.2020.107985] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 08/10/2020] [Accepted: 08/30/2020] [Indexed: 01/16/2023]
Abstract
Acanthamoeba castellanii is a protist that has a high predation efficiency for bacteria in a number of monoxenic culture experiments. However, the role of A. castellanii in the microbial community is still unknown because of the lack of studies on multiple-species interactions. The aim of this study was to investigate the change of bacterial composition after A. castellanii emerges in a water environment. We added A. castellanii to an environmental water sample and incubated it for two days. Then, we performed 16S ribosomal RNA sequencing techniques to analyze the changes in bacterial composition. In this study, A. castellanii slightly increased the relative abundance of a few opportunistic pathogens, such as Legionella, Roseomonas, and Haemophilus. This result may be related to the training ground hypothesis. On the other hand, the growth of some bacteria was inhibited, such as Cyanobacteria and Firmicutes. Although A. castellanii did not drastically change the whole bacterial community, we surprisingly found the dissolved oxygen concentration was increased after incubation with A. castellanii. We applied environmental water at the laboratory scale to investigate the interactions among A. castellanii, complex microbial communities and the environment. We identified the bacteria that are sensitive to A. castellanii and further found the novel relationship between dissolved oxygen and microbial interaction. Our results helped to clarify the role of A. castellanii in microbial communities.
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Affiliation(s)
- Chih-Ming Tsai
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
| | - Jenn-Wei Chen
- 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 Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan, Taiwan; Department of Parasitology, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
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14
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The Antifungal Drug Isavuconazole Is both Amebicidal and Cysticidal against Acanthamoeba castellanii. Antimicrob Agents Chemother 2020; 64:AAC.02223-19. [PMID: 32094126 DOI: 10.1128/aac.02223-19] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Accepted: 02/17/2020] [Indexed: 11/20/2022] Open
Abstract
Current treatments for Acanthamoeba keratitis rely on a combination of chlorhexidine gluconate, propamidine isethionate, and polyhexamethylene biguanide. These disinfectants are nonspecific and inherently toxic, which limits their effectiveness. Furthermore, in 10% of cases, recurrent infection ensues due to the difficulty in killing both trophozoites and double-walled cysts. Therefore, development of efficient, safe, and target-specific drugs which are capable of preventing recurrent Acanthamoeba infection is a critical unmet need for averting blindness. Since both trophozoites and cysts contain specific sets of membrane sterols, we hypothesized that antifungal drugs targeting sterol 14-demethylase (CYP51), known as conazoles, would have deleterious effects on A. castellanii trophozoites and cysts. To test this hypothesis, we first performed a systematic screen of the FDA-approved conazoles against A. castellanii trophozoites using a bioluminescence-based viability assay adapted and optimized for Acanthamoeba The most potent drugs were then evaluated against cysts. Isavuconazole and posaconazole demonstrated low nanomolar potency against trophozoites of three clinical strains of A. castellanii Furthermore, isavuconazole killed trophozoites within 24 h and suppressed excystment of preformed Acanthamoeba cysts into trophozoites. The rapid action of isavuconazole was also evident from the morphological changes at nanomolar drug concentrations causing rounding of trophozoites within 24 h of exposure. Given that isavuconazole has an excellent safety profile, is well tolerated in humans, and blocks A. castellanii excystation, this opens an opportunity for the cost-effective repurposing of isavuconazole for the treatment of primary and recurring Acanthamoeba keratitis.
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15
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Thái TL, Kang JM, Lê HG, Lee J, Yoo WG, Shin HJ, Sohn WM, Na BK. Fowlerstefin, a cysteine protease inhibitor of Naegleria fowleri, induces inflammatory responses in BV-2 microglial cells in vitro. Parasit Vectors 2020; 13:41. [PMID: 31996242 PMCID: PMC6988287 DOI: 10.1186/s13071-020-3909-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 01/15/2020] [Indexed: 01/30/2023] Open
Abstract
Background Naegleria fowleri is a free-living amoeba that causes an opportunistic fatal infection known as primary amoebic meningoencephalitis (PAM) in humans. Cysteine proteases produced by the amoeba may play critical roles in the pathogenesis of infection. In this study, a novel cysteine protease inhibitor of N. fowleri (fowlerstefin) was characterized to elucidate its biological function as an endogenous cysteine protease inhibitor of the parasite as well as a pathogenic molecule that induces immune responses in microglial cells. Methods Recombinant fowlerstefin was expressed in Escherichia coli. The inhibitory activity of fowlerstefin against several cysteine proteases, including human cathepsins B and L, papain and NfCPB-L, was analyzed. Fowlerstefin-induced pro-inflammatory response in BV-2 microglial cells was anayzed by cytokine array assay, reverse transcription polymerase chain reaction, and enzyme-linked immunosorbent assay. Results Fowlerstefin is a cysteine protease inhibitor with a monomeric structure, and belongs to the stefin family. Recombinant fowlerstefin effectively inhibited diverse cysteine proteases including cathepsin B-like cysteine proteases of N. fowleri (NfCPB-L), human cathepsins B and L, and papain. Expression of fowlerstefin in the amoeba was optimal during the trophozoite stage and gradually decreased in cysts. Fowlerstefin induced an inflammatory response in BV-2 microglial cells. Fowlerstefin induced the expression of several pro-inflammatory cytokines and chemokines including IL-6 and TNF in BV-2 microglial cells. Fowlerstefin-induced expression of IL-6 and TNF in BV-2 microglial cells was regulated by mitogen-activated protein kinase (MAPKs). The inflammatory response induced by fowlerstefin in BV-2 microglial cells was downregulated via inhibition of NF-κB and AP-1. Conclusions Fowlerstefin is a pathogenic molecule that stimulates BV-2 microglial cells to produce pro-inflammatory cytokines through NF-κB- and AP-1-dependent MAPK signaling pathways. Fowlerstefin-induced inflammatory cytokines exacerbate the inflammatory response in N. fowleri-infected areas and contribute to the pathogenesis of PAM.
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Affiliation(s)
- Thị Lam Thái
- Department of Parasitology and Tropical Medicine and Institute of Health Sciences, Gyeongsang National University College of Medicine, Jinju, 52727, Republic of Korea.,BK21Plus Team for Anti-aging Biotechnology and Industry, Department of Convergence Medical Science, Gyeongsang National University, Jinju, 52727, Republic of Korea
| | - Jung-Mi Kang
- Department of Parasitology and Tropical Medicine and Institute of Health Sciences, Gyeongsang National University College of Medicine, Jinju, 52727, Republic of Korea.,BK21Plus Team for Anti-aging Biotechnology and Industry, Department of Convergence Medical Science, Gyeongsang National University, Jinju, 52727, Republic of Korea
| | - Hương Giang Lê
- Department of Parasitology and Tropical Medicine and Institute of Health Sciences, Gyeongsang National University College of Medicine, Jinju, 52727, Republic of Korea.,BK21Plus Team for Anti-aging Biotechnology and Industry, Department of Convergence Medical Science, Gyeongsang National University, Jinju, 52727, Republic of Korea
| | - Jinyoung Lee
- Department of Tropical Medicine and Inha Research Institute for Medical Sciences, Inha University School of Medicine, Incheon, 22212, Republic of Korea
| | - Won Gi Yoo
- Department of Medical Environmental Biology, Chung-Ang University College of Medicine, Seoul, 06974, Republic of Korea
| | - Ho-Joon Shin
- Department of Microbiology, Ajou University School of Medicine, Suwon, 16499, Republic of Korea.,Department of Biomedical Science, Ajou University School of Medicine, Suwon, 16499, Republic of Korea
| | - Woon-Mok Sohn
- Department of Parasitology and Tropical Medicine and Institute of Health Sciences, Gyeongsang National University College of Medicine, Jinju, 52727, Republic of Korea
| | - Byoung-Kuk Na
- Department of Parasitology and Tropical Medicine and Institute of Health Sciences, Gyeongsang National University College of Medicine, Jinju, 52727, Republic of Korea. .,BK21Plus Team for Anti-aging Biotechnology and Industry, Department of Convergence Medical Science, Gyeongsang National University, Jinju, 52727, Republic of Korea.
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16
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Kang H, Sohn HJ, Seo GE, Seong GS, Ham AJ, Park AY, Jung SY, Lee SE, Cho SH, Shin HJ. Molecular detection of free-living amoebae from Namhangang (southern Han River) in Korea. Sci Rep 2020; 10:335. [PMID: 31942007 PMCID: PMC6962209 DOI: 10.1038/s41598-019-57347-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 12/20/2019] [Indexed: 11/19/2022] Open
Abstract
The free-living amoebae Naegleria spp. and Acanthamoeba spp. exist in the natural environment and are sometimes causal agents of lethal primary amoebic meningoencephalitis (PAM), amoebic keratitis (AK) and granulomatous amebic encephalitis (GAE) in humans, respectively. To ascertain the existence of free-living amoebae in Korea, water samples were collected from the Korean hydrosphere, Namhangang (southern Han River), an active location for water skiing and recreation. Samples underwent two-step filtration and were cultured on non-nutrient agar medium with inactivated E. coli. The remaining samples were subjected to PCR for primarily the 18S small ribosomal RNA gene and gene sequencing. Similarities in 18S rDNA sequences, in comparison with various reference amoebae in GenBank, showed 86~99% homology with N. gruberi, N. philippinensis, N. clarki, A. polyphaga, A. castellannii, and Hartmannella (Vermamoeba) vermiformis. Therefore, this study will be useful for seasonal detection of free-living amoebae from various Korean hydrospheres in future studies.
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Affiliation(s)
- Heekyoung Kang
- Department of Microbiology, Ajou University School of Medicine, Suwon, 16499, Republic of Korea.,Department of Biomedical Science, Graduate School of Ajou University, Suwon, 16499, Republic of Korea
| | - Hae-Jin Sohn
- Department of Microbiology, Ajou University School of Medicine, Suwon, 16499, Republic of Korea.,Department of Biomedical Science, Graduate School of Ajou University, Suwon, 16499, Republic of Korea
| | - Ga-Eun Seo
- Department of Microbiology, Ajou University School of Medicine, Suwon, 16499, Republic of Korea.,Department of Biomedical Science, Graduate School of Ajou University, Suwon, 16499, Republic of Korea
| | - Gi-Sang Seong
- Department of Microbiology, Ajou University School of Medicine, Suwon, 16499, Republic of Korea.,Department of Biomedical Science, Graduate School of Ajou University, Suwon, 16499, Republic of Korea
| | - A-Jeong Ham
- Department of Microbiology, Ajou University School of Medicine, Suwon, 16499, Republic of Korea.,Department of Biomedical Science, Graduate School of Ajou University, Suwon, 16499, Republic of Korea
| | - A-Young Park
- Department of Microbiology, Ajou University School of Medicine, Suwon, 16499, Republic of Korea
| | - Suk-Yul Jung
- Department of Biomedical Laboratory Science, Molecular Diagnostics Research Institute, School of Health and Medicine, Namseoul University, Cheonan, 31020, Republic of Korea
| | - Sang-Eun Lee
- Division of Vectors and Parasitic Diseases, Korea Centers for Diseases Control and Prevention, Osong, 363-951, Republic of Korea
| | - Shin-Hyeong Cho
- Division of Vectors and Parasitic Diseases, Korea Centers for Diseases Control and Prevention, Osong, 363-951, Republic of Korea
| | - Ho-Joon Shin
- Department of Microbiology, Ajou University School of Medicine, Suwon, 16499, Republic of Korea. .,Department of Biomedical Science, Graduate School of Ajou University, Suwon, 16499, Republic of Korea.
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17
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The Acanthamoeba SBDS, a cytoskeleton-associated gene, is highly expressed during phagocytosis and encystation. JOURNAL OF MICROBIOLOGY, IMMUNOLOGY, AND INFECTION = WEI MIAN YU GAN RAN ZA ZHI 2019; 54:482-489. [PMID: 31882330 DOI: 10.1016/j.jmii.2019.11.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 10/09/2019] [Accepted: 11/18/2019] [Indexed: 01/18/2023]
Abstract
BACKGROUND/PURPOSE Shwachman-Bodian-Diamond syndrome (SBDS) protein is widely present in eukaryotes from vertebrates to protozoa. However, there are several variants within species, and previous studies have shown evidence that they may have additional functions. There are two SBDS-related proteins in Acanthamoeba. One is an rRNA metabolism protein of the SBDS family (ACA1_142090), and the other is SBDS (ACA1_204560). Although there is a conserved SBDS domain in the Acanthamoeba SBDS (ACA1_204560; AcSBDS), its function has not been reported. The aims of this study were to characterize the expression of AcSBDS during phagocytosis and encystation. METHODS AcSBDS-specific primer was designed to amplify the genomic AcSBDS of Acanthamoeba ATCC-30010. The AcSBDS expression was examined using reverse transcription polymerase chain reaction (RT-PCR) and immunostaining after phagocytosis and encystation treatment. RESULTS In this study, we found that the mRNA expression level of AcSBDS increased rapidly and that alternative splice variants were detected during phagocytosis and encystation processes. The results of immunofluorescence staining showed that the AcSBDS proteins accumulated surrounding phagocytosed bacteria. CONCLUSION Our results suggest that AcSBDS may not only have ribosomal maturation features but also have cytoskeleton-associated functions related to phagocytosis and encystation.
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18
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Chen CH, Huang CL, He MS, Huang FC, Lin WC. Characterisation of the β-lactam resistance enzyme in Acanthamoeba castellanii. Int J Antimicrob Agents 2019; 55:105823. [PMID: 31622653 DOI: 10.1016/j.ijantimicag.2019.10.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 09/27/2019] [Accepted: 10/05/2019] [Indexed: 12/11/2022]
Abstract
β-Lactams are well known as the best antibiotics for inhibiting the cross-linking between adjacent polysaccharide chains and peptides in the peptidoglycan layer of bacterial cell walls, causing bacterial cell lysis. There are no reports on the action of and resistance mechanisms to β-lactams in protozoa. Acanthamoeba castellanii is a free-living protozoan pathogen capable of causing blinding keratitis and fatal granulomatous encephalitis. When Acanthamoeba is exposed to harsh conditions, it differentiates into the cyst stage to avoid environmental stresses, such as drug treatment. In this study, it was shown that the mature encystation rate of A. castellanii is decreased by treatment with cefotaxime (CTX) and clavulanic acid (CLA); however, the drugs do not kill the amoeba. We hypothesise that β-lactam antibiotics may disturb synthesis of the double cell wall during the encystation process of Acanthamoeba. Interestingly, CTX is considered a powerful β-lactam, whereas CLA is considered a weak β-lactam but an efficient β-lactamase inhibitor. It was demonstrated that Acanthamoeba expresses β-lactamases to prevent inhibition of the encystation process by β-lactams. To reveal the functions of Acanthamoeba β-lactamases, a recombinant Acanthamoeba β-lactamase was produced in Escherichia coli that conferred resistance to β-lactams such as CTX, cefuroxime, penicillin and meropenem. Consequently, we suggest that Acanthamoeba produces enzymes similar to β-lactamases to avoid interference from the environment. Here we provide a new point of view on an important gene responsible for drug resistance and advocate for the development of more efficient treatment against Acanthamoeba infection.
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Affiliation(s)
- Chun-Hsien Chen
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Chao-Li Huang
- Institute of Tropical Plant Sciences and Microbiology, National Cheng Kung University, Tainan, Taiwan
| | - Ming-Shan He
- Department of Ophthalmology, Buddhist Tzu Chi General Hospital, Hualien, Taiwan; Department of Ophthalmology and Visual Science, Tzu Chi University, Hualien, Taiwan
| | - Fu-Chin Huang
- Department of Ophthalmology, National Cheng Kung University Hospital, 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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19
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Sohn HJ, Seo GE, Lee JH, Ham AJ, Oh YH, Kang H, Shin HJ. Cytopathic Change and Inflammatory Response of Human Corneal Epithelial Cells Induced by Acanthamoeba castellanii Trophozoites and Cysts. THE KOREAN JOURNAL OF PARASITOLOGY 2019; 57:217-223. [PMID: 31284343 PMCID: PMC6616168 DOI: 10.3347/kjp.2019.57.3.217] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Accepted: 04/18/2019] [Indexed: 12/03/2022]
Abstract
Acanthamoeba castellanii has ubiquitous distribution and causes primary acanthamoebic keratitis (AK). AK is a common disease in contact lens wearers and results in permanent visual impairment or blindness. In this study, we observed the cytopathic effect, in vitro cytotoxicity, and secretion pattern of cytokines in human corneal epithelial cells (HCECs) induced by A. castellanii trophozoites and/or cysts. Morphological observation revealed that panked dendritic HCECs co-cultured with amoeba cysts had changed into round shape and gradually died. Such changes were more severe in co-culture with cyst than those of co-cultivation with trophozoites. In vitro cytotoxicity assay revealed the highest cytotoxicity to HCECs in the co-culture system with amoeba cysts. A. castellanii induced the expression of IL-1α, IL-6, IL-8, and CXCL1 in HCECs. Secreted levels of IL-1α, IL-6, and IL-8 in HCECs co-cultured with both trophozoites and cysts were increased at an early incubation time (3 and 6 hr). These results suggested that cytopathic changes and pro-inflammatory cytokines release of HCECs in response to A. castellanii, especially amoebic cysts, are an important mechanism for AK development.
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Affiliation(s)
- Hae-Jin Sohn
- Department of Microbiology, Ajou University School of medicine, and Department of Biomedical Science, Graduate School of Ajou University, Suwon 16499, Korea
| | - Ga-Eun Seo
- Department of Microbiology, Ajou University School of medicine, and Department of Biomedical Science, Graduate School of Ajou University, Suwon 16499, Korea
| | - Jae-Ho Lee
- Department of Microbiology, Ajou University School of medicine, and Department of Biomedical Science, Graduate School of Ajou University, Suwon 16499, Korea
| | - A-Jeong Ham
- Department of Microbiology, Ajou University School of medicine, and Department of Biomedical Science, Graduate School of Ajou University, Suwon 16499, Korea
| | - Young-Hwan Oh
- Department of Microbiology, Ajou University School of medicine, and Department of Biomedical Science, Graduate School of Ajou University, Suwon 16499, Korea
| | - Heekyoung Kang
- Department of Microbiology, Ajou University School of medicine, and Department of Biomedical Science, Graduate School of Ajou University, Suwon 16499, Korea
| | - Ho-Joon Shin
- Department of Microbiology, Ajou University School of medicine, and Department of Biomedical Science, Graduate School of Ajou University, Suwon 16499, Korea
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20
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Sohn HJ, Song KJ, Kang H, Ham AJ, Lee JH, Chwae YJ, Kim K, Park S, Kim JH, Shin HJ. Cellular characterization of actin gene concerned with contact-dependent mechanisms in Naegleria fowleri. Parasite Immunol 2019; 41:e12631. [PMID: 31077592 DOI: 10.1111/pim.12631] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 05/07/2019] [Accepted: 05/08/2019] [Indexed: 12/20/2022]
Abstract
Free-living amoeba, Naegleria fowleri, destroys target cells through contact-dependent mechanisms, such as phagocytosis and/or trogocytosis. A previous experiment showed that the nf-actin gene consisted of 1.2 kbp, produced a 50.1 kDa recombinant protein (Nf-actin), and was localized on the cytoskeleton, pseudopodia and amoebastome. In this study, cellular characterization of the nf-actin gene concerned with contact-dependent mechanisms in N fowleri was performed. The nf-actin gene was amplified from a gene-cloned vector, pEXQP5-T7/NT TOPO. The nf-actin gene was introduced into the Ubi-pEGFP-C2 vector, and Ubi-pEGFP-C2/nf-actin was transfected into N fowleri trophozoites. Strong GFP fluorescence was detected in N fowleri trophozoites transfected with Ubi-pEGFP-C2/nf-actin. Expression of EGFP-Nf-actin protein was detected by Western blot analysis. The nf-actin-overexpressing N fowleri showed significantly increased adhesion activity against extracellular matrix components, fibronectin, collagen I and fibrinogen, compared with wild-type N fowleri. Moreover, nf-actin-overexpressing N fowleri showed increased phagocytic activity and cytotoxicity in comparison with wild-type N fowleri. In summary, the overexpressed nf-actin gene has an important function in ability to increase cell adhesion, cytotoxicity and phagocytosis by N fowleri.
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Affiliation(s)
- Hae-Jin Sohn
- Department of Microbiology, Ajou University School of Medicine, Suwon, Korea.,Department of Biomedical Science, Graduate School of Ajou University, Suwon, Korea
| | | | - Heekyoung Kang
- Department of Microbiology, Ajou University School of Medicine, Suwon, Korea.,Department of Biomedical Science, Graduate School of Ajou University, Suwon, Korea
| | - A-Jeong Ham
- Department of Microbiology, Ajou University School of Medicine, Suwon, Korea.,Department of Biomedical Science, Graduate School of Ajou University, Suwon, Korea
| | - Jae-Ho Lee
- Department of Microbiology, Ajou University School of Medicine, Suwon, Korea.,Department of Biomedical Science, Graduate School of Ajou University, Suwon, Korea
| | - Yong-Joon Chwae
- Department of Microbiology, Ajou University School of Medicine, Suwon, Korea.,Department of Biomedical Science, Graduate School of Ajou University, Suwon, Korea
| | - Kyongmin Kim
- Department of Microbiology, Ajou University School of Medicine, Suwon, Korea.,Department of Biomedical Science, Graduate School of Ajou University, Suwon, Korea
| | - Sun Park
- Department of Microbiology, Ajou University School of Medicine, Suwon, Korea.,Department of Biomedical Science, Graduate School of Ajou University, Suwon, Korea
| | - Jong-Hyun Kim
- Institute of Animal Medicine, College of Veterinary Medicine, Gyeongsang National University, Jinju, Korea
| | - Ho-Joon Shin
- Department of Microbiology, Ajou University School of Medicine, Suwon, Korea.,Department of Biomedical Science, Graduate School of Ajou University, Suwon, Korea
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21
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Maal-Bared R, Dixon B, Axelsson-Olsson D. Fate of internalized Campylobacter jejuni and Mycobacterium avium from encysted and excysted Acanthamoeba polyphaga. Exp Parasitol 2019; 199:104-110. [PMID: 30902623 DOI: 10.1016/j.exppara.2019.03.011] [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: 02/01/2019] [Revised: 03/16/2019] [Accepted: 03/18/2019] [Indexed: 10/27/2022]
Abstract
Association of the water- and foodborne pathogen Campylobacter jejuni with free-living Acanthamoeba spp. trophozoites enhances C. jejuni survival and resistance to biocides and starvation. When facing less than optimal environmental conditions, however, the Acanthamoeba spp. host can temporarily transform from trophozoite to cyst and back to trophozoite, calling the survival of the internalized symbiont and resulting public health risk into question. Studies investigating internalized C. jejuni survival after A. castellanii trophozoite transformation have neither been able to detect its presence inside the Acanthamoeba cyst after encystation nor to confirm its presence upon excystation of trophozoites through culture-based techniques. The purpose of this study was to detect C. jejuni and Mycobacterium avium recovered from A. polyphaga trophozoites after co-culture and induction of trophozoite encystation using three different encystation methods (Neff's medium, McMillen's medium and refrigeration), as well as after cyst excystation. Internalized M. avium was used as a positive control, since studies have consistently detected the organism after co-culture and after host excystation. Concentrations of C. jejuni in A. polyphaga trophozoites were 4.5 × 105 CFU/ml, but it was not detected by PCR or culture post-encystation. This supports the hypothesis that C. jejuni may be digested during encystation of the amoebae. M. avium was recovered at a mean concentration of 1.9 × 104 from co-cultured trophozoites and 4.4 × 101 CFU/ml after excystation. The results also suggest that M. avium recovery post-excystation was statistically significantly different based on which encystation method was used, ranging from 1.3 × 101 for Neff's medium to 5.4 × 101 CFU/ml for refrigeration. No M. avium was recovered from A. polyphaga cysts when trophozoites were encysted by McMillen's medium. Since C. jejuni internalized in cysts would be more likely to survive harsh environmental conditions and disinfection, a better understanding of potential symbioses between free-living amoebae and campylobacters in drinking water distribution systems and food processing environments is needed to protect public health. Future co-culture experiments examining survival of internalized C. jejuni should carefully consider the encystation media used, and include molecular detection tools to falsify the hypothesis that C. jejuni may be present in a viable but not culturable state.
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Affiliation(s)
- Rasha Maal-Bared
- Centre for Research on Environmental Microbiology, University of Ottawa, Faculty of Medicine, 451 Smyth Road, Ottawa, ON, K1H 8M5, Canada.
| | - Brent Dixon
- Bureau of Microbial Hazards, Food Directorate, Health Canada, Ottawa, ON, K1A 0K9, Canada.
| | - Diana Axelsson-Olsson
- Centre for Ecology and Evolution in Microbial Model Systems, Linnaeus University, Kalmar, Sweden.
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22
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Seong GS, Sohn HJ, Kang H, Seo GE, Kim JH, Shin HJ. Production and characterization of monoclonal antibodies against cathepsin B and cathepsin B-Like proteins of Naegleria fowleri. Exp Parasitol 2017; 183:171-177. [DOI: 10.1016/j.exppara.2017.09.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Revised: 08/18/2017] [Accepted: 09/11/2017] [Indexed: 11/15/2022]
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