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Anwar A, Fatima I, Khan KM, Daalah M, Alawfi BS, Khan NA, Anwar A. Anti-Acanthamoebic effects of silver-conjugated tetrazole nanoparticle. Exp Parasitol 2024; 265:108827. [PMID: 39147119 DOI: 10.1016/j.exppara.2024.108827] [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: 04/19/2024] [Revised: 08/08/2024] [Accepted: 08/12/2024] [Indexed: 08/17/2024]
Abstract
Tetrazoles are five-membered ring aromatic heterocyclic molecules that consist of one carbon and four nitrogen atoms. Several tetrazole-based drugs have shown promising activities against bacteria, fungi, asthma, cancer, hypertension etc. The overall aim of this study was to determine anti-Acanthamoebic properties of tetrazoles and tetrazole-conjugated silver nanoparticles. Tetrazole-conjugated silver nanoparticles were synthesized and confirmed using ultraviolet-visible spectrometry, Dynamic light scattering, and Fourier-transform infrared spectroscopy. Using amoebicidal, encystment, and excystment assays, the findings revealed that tetrazoles exhibited antiamoebic properties and these effects were enhanced when conjugated with silver nanoparticles. Importantly, conjugation with silver nanoparticles inhibited parasite-mediated human cell death in vitro, as measured by lactate dehydrogenase release, but it reduced toxic effects of drugs alone on human cells. Overall, these results showed clearly that tetrazoles exhibit potent antiamoebic properties which can be enhanced by conjugation with silver nanoparticles and these potential in the rational development of therapeutic interventions against parasitic infections such as keratitis and granulomatous amoebic encephalitis due to pathogenic Acanthamoeba.
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Affiliation(s)
- Areeba Anwar
- School of Medical and Life Sciences, Sunway University, Malaysia
| | - Itrat Fatima
- H. E. J. Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi, 75270, Pakistan
| | - Khalid Mohammed Khan
- H. E. J. Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi, 75270, Pakistan
| | - Meshal Daalah
- Department of Medical Laboratory Sciences, Faculty of Allied Health Sciences, Health Sciences Center, Kuwait University, Jabriya, Kuwait
| | - Bader S Alawfi
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Taibah University, Madinah, 42353, Saudi Arabia
| | | | - Ayaz Anwar
- School of Medical and Life Sciences, Sunway University, Malaysia
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2
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Phendinvay O, Thongseesuksai T, Boonmars T, Laummaunwai P. EVALUATION OF THE CYSTICIDAL ACTIVITY OF CHLOROCRESOL AGAINST ACANTHAMOEBA POLYPHAGA. J Parasitol 2024; 110:423-427. [PMID: 39245448 DOI: 10.1645/24-15] [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] [Indexed: 09/10/2024] Open
Abstract
Chlorocresol has antibacterial and antifungal properties, yet its effectiveness in eradicating Acanthamoeba spp. remains unexplored. Acanthamoeba species trophozoites are usually sensitive to biocides, whereas cysts tend to be more resistant. This study aimed to evaluate the cysticidal activity of chlorocresol against Acanthamoeba polyphaga. Chlorocresol concentrations of 0.02, 0.04, and 0.08% were prepared and A. polyphaga cysts were incubated at room temperature (28-37 C) for 1, 24, 48, and 72 hr at each concentration. Cyst viability was evaluated using trypan blue staining and the percentage of nonviable cysts was calculated. For qualification assays, treated cysts were cultured on nonnutrient agar medium coated with Escherichia coli, incubated at 30 C, observed under a stereomicroscope for 30 days, and inoculated into peptone-yeast extract-glucose medium at 30 C for 72 hr. The results revealed that the A. polyphaga cysts were susceptible to 0.02, 0.04, and 0.08% chlorocresol. Chlorocresol made a significant difference in viability (P < 0.001) compared with the nontreated control for the same incubation time. This is the first study to examine the efficacy of chlorocresol against A. polyphaga cysts and it was highly effective. Chlorocresol could thus serve as an alternative chemical disinfectant for the eradication of A. polyphaga cysts as well as a prophylactic against transmission of other pathogenic microorganisms for which Acanthamoeba species can act as a carrier.
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Affiliation(s)
- Orlanath Phendinvay
- Department of Parasitology, Faculty of Medicine, Khon Kaen University, Khon Kaen Province, Mitraparp Road, Thailand 40002
| | - Thaksaporn Thongseesuksai
- Department of Parasitology, Faculty of Medicine, Khon Kaen University, Khon Kaen Province, Mitraparp Road, Thailand 40002
| | - Thidarut Boonmars
- Department of Parasitology, Faculty of Medicine, Khon Kaen University, Khon Kaen Province, Mitraparp Road, Thailand 40002
- Neglected, Zoonosis and Vector-Borne Disease Research Group, Khon Kaen University, Mitraparp Road, Thailand 40002
| | - Porntip Laummaunwai
- Department of Parasitology, Faculty of Medicine, Khon Kaen University, Khon Kaen Province, Mitraparp Road, Thailand 40002
- Neglected, Zoonosis and Vector-Borne Disease Research Group, Khon Kaen University, Mitraparp Road, Thailand 40002
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3
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Ahmed U, Ong SK, Khan KM, Siddiqui R, Khan NA, Shaikh MF, Alawfi BS, Anwar A. Effect of embelin on inhibition of cell growth and induction of apoptosis in Acanthamoeba castellanii. Arch Microbiol 2023; 205:360. [PMID: 37898989 DOI: 10.1007/s00203-023-03698-3] [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: 08/23/2023] [Accepted: 10/02/2023] [Indexed: 10/31/2023]
Abstract
Acanthamoeba castellanii is the causative agent of fatal encephalitis and blinding keratitis. Current therapies remain a challenge, hence there is a need to search for new therapeutics. Here, we tested embelin (EMB) and silver nanoparticles doped with embelin (EMB-AgNPs) against A. castellanii. Using amoebicidal assays, the results revealed that both compounds inhibited the viability of Acanthamoeba, having an IC50 of 27.16 ± 0.63 and 13.63 ± 1.08 μM, respectively, while causing minimal cytotoxicity against HaCaT cells in vitro. The findings suggest that both samples induced apoptosis through the mitochondria-mediated pathway. Differentially expressed genes analysis showed that 652 genes were uniquely expressed in treated versus untreated cells, out of which 191 were significantly regulated in the negative control vs. conjugate. Combining the analysis, seven genes (ARIH1, RAP1, H3, SDR16C5, GST, SRX1, and PFN) were highlighted as the most significant (Log2 (FC) value ± 4) for the molecular mode of action in vitro. The KEGG analysis linked most of the genes to apoptosis, the oxidative stress signaling pathway, cytochrome P450, Rap1, and the oxytocin signaling pathways. In summary, this study provides a thorough framework for developing therapeutic agents against microbial infections using EMB and EMB-AgNPs.
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Affiliation(s)
- Usman Ahmed
- Department of Biological Sciences, School of Medical and Life Sciences, Sunway University, Subang Jaya, 47500, Selangor, Malaysia
| | - Seng-Kai Ong
- Department of Biological Sciences, School of Medical and Life Sciences, Sunway University, Subang Jaya, 47500, Selangor, Malaysia
| | - Khalid Mohammed Khan
- H. E. J. Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi, Pakistan
- Department of Clinical Pharmacy, Institute for Research and Medical Consultations (IRMC), Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia
| | | | - Naveed Ahmed Khan
- Microbiota Research Center, Istinye University, 34010, Istanbul, Turkey.
| | - Mohd Farooq Shaikh
- Neuropharmacology Research Laboratory, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, 47500, Bandar Sunway, Malaysia
- School of Dentistry and Medical Sciences, Charles Sturt University, Orange, New South Wales, Australia
| | - Bader Saleem Alawfi
- Department of Medical Laboratories Technology, College of Applied Medical Sciences, Taibah University, 42353, Madinah, Saudi Arabia
| | - Ayaz Anwar
- Department of Biological Sciences, School of Medical and Life Sciences, Sunway University, Subang Jaya, 47500, Selangor, Malaysia.
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4
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Wang Y, Jiang L, Zhao Y, Ju X, Wang L, Jin L, Fine RD, Li M. Biological characteristics and pathogenicity of Acanthamoeba. Front Microbiol 2023; 14:1147077. [PMID: 37089530 PMCID: PMC10113681 DOI: 10.3389/fmicb.2023.1147077] [Citation(s) in RCA: 19] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Accepted: 03/21/2023] [Indexed: 04/25/2023] Open
Abstract
Acanthamoeba is an opportunistic protozoa, which exists widely in nature and is mainly distributed in soil and water. Acanthamoeba usually exists in two forms, trophozoites and cysts. The trophozoite stage is one of growth and reproduction while the cyst stage is characterized by cellular quiescence, commonly resulting in human infection, and the lack of effective monotherapy after initial infection leads to chronic disease. Acanthamoeba can infect several human body tissues such as the skin, cornea, conjunctiva, respiratory tract, and reproductive tract, especially when the tissue barriers are damaged. Furthermore, serious infections can cause Acanthamoeba keratitis, granulomatous amoebic encephalitis, skin, and lung infections. With an increasing number of Acanthamoeba infections in recent years, the pathogenicity of Acanthamoeba is becoming more relevant to mainstream clinical care. This review article will describe the etiological characteristics of Acanthamoeba infection in detail from the aspects of biological characteristic, classification, disease, and pathogenic mechanism in order to provide scientific basis for the diagnosis, treatment, and prevention of Acanthamoeba infection.
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Affiliation(s)
- Yuehua Wang
- College of Laboratory Medicine, Jilin Medical University, Jilin City, China
| | - Linzhe Jiang
- General Surgery, Jilin People’s Hospital, Jilin City, China
| | - Yitong Zhao
- College of Laboratory Medicine, Jilin Medical University, Jilin City, China
| | - Xiaohong Ju
- College of Laboratory Medicine, Jilin Medical University, Jilin City, China
| | - Le Wang
- Department of Laboratory Medicine, Jilin Hospital of Integrated Chinese and Western Medicine, Jilin City, China
| | - Liang Jin
- Department of Laboratory Medicine, Jilin Hospital of Integrated Chinese and Western Medicine, Jilin City, China
| | - Ryan D. Fine
- Center for Human Genetics and Genomics, New York University Grossman School of Medicine, New York City, NY, United States
| | - Mingguang Li
- College of Laboratory Medicine, Jilin Medical University, Jilin City, China
- *Correspondence: Mingguang Li,
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5
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Novel Plant-Based Metabolites as Disinfectants against Acanthamoeba castellanii. Antibiotics (Basel) 2022; 11:antibiotics11020248. [PMID: 35203850 PMCID: PMC8868186 DOI: 10.3390/antibiotics11020248] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 02/04/2022] [Accepted: 02/10/2022] [Indexed: 01/27/2023] Open
Abstract
Due to global warming, coupled with global water shortages and the reliance of the public on household water tanks, especially in developing countries, it is anticipated that infections caused by free-living amoebae such as Acanthamoeba will rise. Thus, the development of novel disinfectant(s) which can target pathogenic free-living amoebae effectively is warranted. Herein, we extracted and isolated several plant-based secondary metabolites as novel disinfectants for use against pathogenic Acanthamoeba. The identity of the compounds was confirmed by nuclear magnetic resonance and tested for antiamoebic activities against clinical isolate of A. castellanii, belonging to the T4 genotype. Amoebicidal assays revealed that the compounds tested showed antiamoebic properties. Betulinic acid and betulin exhibited parasite killing of more than 65%. When tested against the cyst stage, betulinic acid, betulin, and vanillic acid inhibited both encystation and excystation processes. Furthermore, the plant-based metabolites significantly inhibited the binding capability of A. castellanii to host cells. Finally, most of the tested compounds displayed minimal cytotoxic activities against human cells and noticeably perturbed amoeba-mediated host cell cytotoxicity. Notably, both alkaloid and betulinic acid showed 20% cytotoxic effects, whereas betulin and lupeol had cytotoxic effects of 24% and 30%, respectively. Overall, our findings indicate that plant-based natural compounds demonstrate anti-Acanthamoebic properties, and they have potential candidates for water disinfectants or contact lens disinfecting solutions, as well as possible therapeutic drugs against Acanthamoeba infections.
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6
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Ziaei Hezarjaribi H, Toluee E, Saberi R, Dadi Moghadam Y, Fakhar M, Akhtari J. In vitro anti- Acanthamoeba activity of the commercial chitosan and nano-chitosan against pathogenic Acanthamoeba genotype T4. J Parasit Dis 2021; 45:921-929. [PMID: 34789973 DOI: 10.1007/s12639-021-01380-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 03/09/2021] [Indexed: 10/21/2022] Open
Abstract
Acanthamoeba keratitis (AK) is a rare but serious infection of the eye and can lead to blindness. The effective and safe medical therapy remains unclear for AK until present. Antimicrobial activity and biological characteristic of chitosan encourage screening of it against Acanthamoeba. Thus, in vitro anti-amoebic activities of commercial chitosan and nano-chitosan were tested on pathogenic Acanthamoeba genotype T4, a causative agent of human AK. The Acanthamoeba spp. was isolated from the keratitis patient. The Acanthamoeba genotype T4 was approved using PCR method followed by sequencing technique. Chitosan nanoparticles was prepared using ionic gelation method and characterized by their physicochemical properties. In the present study, the in vitro activity of serial dilutions (12.5, 25, 50, 100, and 200 µL/mL) of commercial chitosan and nano-chitosan were evaluated against Acanthamoeba trophozoites and cysts. The finding of nano-chitosan particle size by DLS was 118 nm with a PDI of about 0.134. Zeta potential value was found to be 42.7 mV. The obtained results showed that the tested chitosan and nano-chitosan presented anti-amoebic activities dependent to time and concentration. The inhibitory effect of the chitosan and nano-chitosan is enhanced by increasing the concentration and incubation time. The inhibitory effect of nano-chitosan on both trophozoites and cyst was more than chitosan. According to the results, nano-chitosan shows the potent activity against Acanthamoeba T4 and could be used for the development of novel and safe therapeutic approaches in the future.
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Affiliation(s)
- Hajar Ziaei Hezarjaribi
- Department of Parasitology, Molecular and Cell Biology Research Center, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran.,Department of Parasitology, Toxoplasmosis Research Center, Communicable Diseases Institute, School of Medicine, Mazandaran University of Medical Sciences, PO Box 48471-91971, Sari, Iran
| | - Elahe Toluee
- Department of Parasitology, Molecular and Cell Biology Research Center, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran.,Student Research Committee, Mazandaran University of Medical Sciences, Sari, Iran
| | - Reza Saberi
- Department of Parasitology, Toxoplasmosis Research Center, Communicable Diseases Institute, School of Medicine, Mazandaran University of Medical Sciences, PO Box 48471-91971, Sari, Iran.,Student Research Committee, Mazandaran University of Medical Sciences, Sari, Iran
| | - Yousef Dadi Moghadam
- Department of Parasitology, Toxoplasmosis Research Center, Communicable Diseases Institute, School of Medicine, Mazandaran University of Medical Sciences, PO Box 48471-91971, Sari, Iran.,Student Research Committee, Mazandaran University of Medical Sciences, Sari, Iran
| | - Mahdi Fakhar
- Department of Parasitology, Toxoplasmosis Research Center, Communicable Diseases Institute, School of Medicine, Mazandaran University of Medical Sciences, PO Box 48471-91971, Sari, Iran.,Iranian National Registry Center for Lophomoniasis and Toxoplasmosis, Imam Khomeini Hospital, Mazandaran University of Medical Sciences, Sari, Iran
| | - Javad Akhtari
- Department of Medical Nanotechnology, Faculty of Medicine, Toxoplasmosis Research Center, Communicable Diseases Institute, Mazandaran University of Medical Sciences, Sari, Iran
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7
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Jin C, Zhao L, Zhao W, Wang L, Zhu S, Xiao Z, Mo Y, Zhang M, Shu L, Qiu R. Transport and Retention of Free-Living Amoeba Spores in Porous Media: Effects of Operational Parameters and Extracellular Polymeric Substances. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:8709-8720. [PMID: 34138552 DOI: 10.1021/acs.est.1c00785] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Amoebas are protists that are widespread in water and soil environments. Some species are pathogenic, inducing potentially lethal effects on humans, making them a major threat to public health. Nonpathogenic amoebas are also of concern because they have the potential to carry a mini-microbiome of bacteria, either transiently or via more long-term stable transport. Due to their resistance to disinfection processes, the physical removal of amoeba by filtration is necessary to prevent their propagation throughout drinking water distribution networks and occurrence in tap water. In this study, a model amoeba species Dictyostelium discoideum was used to study the transport and retention behavior of amoeba spores in porous media. The key factors affecting the transport behavior of amoeba spores in fully saturated media were comprehensively evaluated, with experiments performed using a quartz crystal microbalance with dissipation monitoring (QCM-D) and parallel plate chamber system. The effects of ionic strength (IS) on the deposition of spores were found to be in contrast to the predicted Derjaguin-Landau-Verwey-Overbeek (DLVO) theory that more deposition is observed under lower-IS conditions. The presence of extracellular polymeric substances (EPS) was found to be the main contributor to deposition behavior. Overall, these results provide plausible evidence for the presence of amoeba in tap water. Furthermore, this is one of the first studies to examine the mechanisms affecting the fate of amoeba spores in porous media, providing a significant baseline for future research to minimize the safety risk presented by amoeba in drinking water systems.
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Affiliation(s)
- Chao Jin
- School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou 510275, China
- Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-Sen University, Guangzhou 510275, China
| | - Lingan Zhao
- School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou 510275, China
- Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-Sen University, Guangzhou 510275, China
| | - Weigao Zhao
- School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou 510275, China
- Department of Environmental Engineering, Tianjin University, Tianjin 300072, China
| | - Luting Wang
- School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou 510275, China
- Environmental Microbiomics Research Center, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-Sen University, Guangzhou 510006, China
| | - Shishu Zhu
- School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou 510275, China
- Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-Sen University, Guangzhou 510275, China
| | - Zihan Xiao
- School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou 510275, China
- Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-Sen University, Guangzhou 510275, China
| | - Yijun Mo
- School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou 510275, China
- Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-Sen University, Guangzhou 510275, China
| | - Miaoyue Zhang
- School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou 510275, China
- Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-Sen University, Guangzhou 510275, China
| | - Longfei Shu
- School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou 510275, China
- Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-Sen University, Guangzhou 510275, China
- Environmental Microbiomics Research Center, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-Sen University, Guangzhou 510006, China
| | - Rongliang Qiu
- School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou 510275, China
- Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-Sen University, Guangzhou 510275, China
- Guangdong Laboratory for Lingnan Modern Agriculture, College of Natural Resources and Environment, South China Agricultural University, Guangzhou 510642, China
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Wang N, Sun H, Liu D, Jiang X, Zheng M, Zhu W, Liu Q, Zheng W, Feng X. Ac-HSP20 Is Associated With the Infectivity and Encystation of Acanthamoeba castellanii. Front Microbiol 2021; 11:595080. [PMID: 33510719 PMCID: PMC7835678 DOI: 10.3389/fmicb.2020.595080] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2020] [Accepted: 12/01/2020] [Indexed: 11/15/2022] Open
Abstract
Acanthamoeba castellanii is a pathogenic and opportunistic free-living amoeba that causes Acanthamoeba keratitis (AK) and granulomatous amebic encephalitis (GAE) in immunocompromised individuals. The biological and pathogenic characterizations behind this opportunistic protozoan is not fully understood. This study aimed to determine the biological functions of heat shock protein (HSP)-20 of A. castellanii (Ac-HSP20) involved in the maintenance of life cycle and the infectivity of A. castellanii. Immunoscreening A. castellanii cDNA library with A. castellanii infected rabbit sera identified three positive clones, one of them was a putative heat shock protein (Ac-HSP20). The recombinant 23 kDa Ac-HSP20 protein (rAc-HSP20) was successfully expressed in Escherichia coli BL21 (DE3) and purified using metal affinity chromatography. The rabbits immunized with rAc-HSP20 produced high titer antibody (1:25,600). Immunolocalization with the antibody identified the expression of native Ac-HSP20 on the surface of both A. castellanii trophozoites and cysts. Further, Western blot with antibody identified that the expression of native Ac-HSP20 was 7.5 times higher in cysts than in trophozoites. Blocking Ac-HSP20 on the membrane of trophozoites with specific antibody or silencing Ac-hsp20 gene transcription by siRNA inhibited their transformation into cysts at the early stage but returned to normal at the late stage by stimulating the transcription of Ac-hsp20. Incubation of trophozoites with anti-Ac-HSP20 IgG increased macrophage-involved phagocytosis to the protozoa and inhibited trophozoite infectivity on the cornea of rabbits compared with that without antibody. Our study provides that Ac-HSP20 is a surface antigen involved in the encystation and infectivity of A. castellanii and thus an important target for vaccine and drug development.
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Affiliation(s)
- Ningning Wang
- Department of Pathogenic Biology, Jilin Medical University, Jilin City, China
| | - Hongyu Sun
- Department of Pathogenic Biology, Jilin Medical University, Jilin City, China
| | - Di Liu
- Department of Pathogenic Biology, Jilin Medical University, Jilin City, China
| | - Xiaoming Jiang
- Department of Pathogenic Biology, Jilin Medical University, Jilin City, China
| | - Meiyu Zheng
- Department of Pathogenic Biology, Jilin Medical University, Jilin City, China
| | - Wenhe Zhu
- Department of Pathogenic Biology, Jilin Medical University, Jilin City, China
| | - Quan Liu
- School of Life Sciences and Engineering, Foshan University, Foshan, China
| | - Wenyu Zheng
- Department of Microsurgery, Jilin City Central Hospital, Jilin City, China
| | - Xianmin Feng
- Department of Pathogenic Biology, Jilin Medical University, Jilin City, China
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Application of Histone Deacetylase Inhibitors MPK472 and KSK64 as a Potential Treatment Option for Acanthamoeba Keratitis. Antimicrob Agents Chemother 2020; 64:AAC.01506-20. [PMID: 32928736 DOI: 10.1128/aac.01506-20] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Accepted: 09/06/2020] [Indexed: 12/12/2022] Open
Abstract
Treatment of Acanthamoeba keratitis (AK) is difficult because Acanthamoeba cysts are resistant to drugs, and as such, successful treatment requires an effective approach that inhibits cyst formation. Histone deacetylase inhibitors (HDACis) are involved in cell proliferation, differentiation, and apoptotic cell death. In this study, the effects of HDACis such as MPK472 and KSK64 on Acanthamoeba castellanii trophozoites and cysts were observed. MPK472 and KSK64 showed at least 60% amoebicidal activity against Acanthamoeba trophozoites at a concentration of 10 μM upon 8 h of treatment. Neither of the two HDACis affected mature cysts, but significant amoebicidal activities (36.4 and 33.9%) were observed against encysting Acanthamoeba following treatment with 5 and 10 μM HDACis for 24 h. Light microscopy and transmission electron microscopy results confirmed that the encystation of Acanthamoeba was inhibited by the two HDACis. In addition to this, low cytopathic effects on human corneal epithelial (HCE) cells were observed following treatment with MPK472 and KSK64 for 24 h. Our results indicate that the HDACis MPK472 and KSK64 could be used as new candidates for the development of an optimal therapeutic option for AK.
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10
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Sharma G, Kalra SK, Tejan N, Ghoshal U. Nanoparticles based therapeutic efficacy against Acanthamoeba: Updates and future prospect. Exp Parasitol 2020; 218:108008. [PMID: 32979343 DOI: 10.1016/j.exppara.2020.108008] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 09/17/2020] [Accepted: 09/23/2020] [Indexed: 12/15/2022]
Abstract
Acanthamoeba sp. is a free living amoeba that causes severe, painful and fatal infections, viz. Acanthamoeba keratitis and granulomatous amoebic encephalitis among humans. Antimicrobial chemotherapy used against Acanthamoeba is toxic to human cells and show side effects as well. Infections due to Acanthamoeba also pose challenges towards currently used antimicrobial treatment including resistance and transformation of trophozoites to resistant cyst forms that can lead to recurrence of infection. Therapeutic agents targeting central nervous system infections caused by Acanthamoeba should be able to cross blood-brain barrier. Nanoparticles based drug delivery put forth an effective therapeutic method to overcome the limitations of currently used antimicrobial chemotherapy. In recent years, various researchers investigated the effectiveness of nanoparticles conjugated drug and/or naturally occurring plant compounds against both trophozoites and cyst form of Acanthamoeba. In the current review, a reasonable effort has been made to provide a comprehensive overview of various nanoparticles tested for their efficacy against Acanthamoeba. This review summarizes the noteworthy details of research performed to elucidate the effect of nanoparticles conjugated drugs against Acanthamoeba.
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Affiliation(s)
- Geetansh Sharma
- Faculty of Applied Sciences & Biotechnology, Shoolini University of Biotechnology & Management Sciences, Bajhol, District Solan, H.P, 173229, India
| | - Sonali K Kalra
- Faculty of Applied Sciences & Biotechnology, Shoolini University of Biotechnology & Management Sciences, Bajhol, District Solan, H.P, 173229, India.
| | - Nidhi Tejan
- Department of Microbiology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Raebareili Road, Lucknow, U.P, 226014, India
| | - Ujjala Ghoshal
- Department of Microbiology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Raebareili Road, Lucknow, U.P, 226014, India
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11
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Encystment Induces Down-Regulation of an Acetyltransferase-Like Gene in Acanthamoeba castellanii. Pathogens 2020; 9:pathogens9050321. [PMID: 32357498 PMCID: PMC7281194 DOI: 10.3390/pathogens9050321] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Revised: 04/19/2020] [Accepted: 04/23/2020] [Indexed: 11/17/2022] Open
Abstract
Acanthamoeba castellanii is a ubiquitous free-living amoeba. Pathogenic strains are causative agents of Acanthamoeba keratitis and granulomatous amoebic encephalitis. In response to adverse conditions, A. castellanii differentiate into cysts, which are metabolically inactive and resistant cells. This process, also named encystment, involves biochemical and genetic modifications that remain largely unknown. This study characterizes the role of the ACA1_384820 Acanthamoeba gene during encystment. This gene encodes a putative N-acetyltransferase, belonging to the Gcn5-related N-acetyltransferase (GNAT) family. We showed that expression of the ACA1_384820 gene was down-regulated as early as two hours after induction of encystment in A. castellanii. Interestingly, overexpression of the ACA1_384820 gene affects formation of cysts. Unexpectedly, the search of homologs of ACA1_384820 in the Eukaryota gene datasets failed, except for some species in the Acanthamoeba genus. Bioinformatics analysis suggested a possible lateral acquisition of this gene from prokaryotic cells. This study enabled us to describe a new Acanthamoeba gene that is down-regulated during encystment.
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Khan NA, Anwar A, Siddiqui R. Acanthamoeba Keratitis: Current Status and Urgent Research Priorities. Curr Med Chem 2019; 26:5711-5726. [DOI: 10.2174/0929867325666180510125633] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Revised: 01/10/2018] [Accepted: 05/01/2018] [Indexed: 12/13/2022]
Abstract
Background:First discovered in the early 1970s, Acanthamoeba keratitis has remained a major eye infection and presents a significant threat to the public health, especially in developing countries. The aim is to present a timely review of our current understanding of the advances made in this field in a comprehensible manner and includes novel concepts and provides clear directions for immediate research priorities.Methods:We undertook a search of bibliographic databases for peer-reviewed research literature and also summarized our published results in this field.Results:The present review focuses on novel diagnostic and therapeutic strategies in details which can provide access to management and treatment of Acanthamoeba keratitis. This coupled with the recently available genome sequence information together with high throughput genomics technology and innovative approaches should stimulate interest in the rational design of preventative and therapeutic measures. Current treatment of Acanthamoeba keratitis is problematic and often leads to infection recurrence. Better understanding of diagnosis, pathogenesis, pathophysiology and therapeutic regimens, would lead to novel strategies in treatment and prophylaxis.
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Affiliation(s)
- Naveed Ahmed Khan
- Department of Biology, Chemistry and Environmental Sciences, College of Arts and Sciences, American University of Sharjah, University City, Sharjah, United Arab Emirates
| | - Ayaz Anwar
- Department of Biology, Chemistry and Environmental Sciences, College of Arts and Sciences, American University of Sharjah, University City, Sharjah, United Arab Emirates
| | - Ruqaiyyah Siddiqui
- Department of Biology, Chemistry and Environmental Sciences, College of Arts and Sciences, American University of Sharjah, University City, Sharjah, United Arab Emirates
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Yim B, Park JH, Jeong H, Hong J, Kim M, Chang M, Chuck RS, Park CY. Effect of Nitric Oxide on Acanthamoeba castellanii. Invest Ophthalmol Vis Sci 2019; 59:3239-3248. [PMID: 29971441 DOI: 10.1167/iovs.18-23786] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Acanthamoeba keratitis is a well-known intractable corneal infectious disease. We investigated the anti-Acanthamoeba effect of exogenous nitric oxide (NO). Methods Acanthamoeba castellanii was axenically cultured and exposed to various concentrations of NO donors, such as sodium nitrite, sodium nitroprusside (SNP), and NO-releasing silica nanoparticles (coated in branched polyethylene imine, size:100 nm), for 1 to 7 days (sodium nitrite and SNP: 0, 0.1, 1, 10, 100, and 1000 μM; silica nanoparticles: 0, 6.25, 12.5, 25, 50, and 100 μg/mL). Human corneal epithelial cells (HCECs) were cultured and exposed to sodium nitrite, SNP (0, 0.1, 1, 10, 100, and 1000 μM), and silica nanoparticles for 1, 2, and 3 days. Results Sodium nitrite and SNP showed a dose-dependent inhibitory effect on A. castellanii viability. A more prominent inhibitory effect was observed with SNP (less than 10% of organisms survived at 7-day culture with 1000 μM) compared with sodium nitrite. However, more cytotoxicity on HCEC was observed with SNP. NO-releasing silica nanoparticles were successfully internalized into the amoebic cytoplasm and accumulated in large vacuoles. Although blank silica nanoparticles had no inhibitory effect on A. castellanii viability, NO-releasing silica nanoparticles showed a dose-dependent amoebicidal effect. Furthermore, no cystic transformation of A. castellanii was observed under a phase contrast microscope or transmission electron microscope after exogenous NO treatment. Conclusions Our results demonstrated the anti-Acanthamoeba effect of exogenous NO. This finding suggests that NO-releasing drug platforms, including nano-carriers, can be a promising therapeutic strategy for Acanthamoeba keratitis.
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Affiliation(s)
- Bora Yim
- Department of Ophthalmology, Dongguk University, Ilsan Hospital, Goyang, South Korea
| | - Joo-Hee Park
- Department of Ophthalmology, Dongguk University, Ilsan Hospital, Goyang, South Korea
| | - Hyejoong Jeong
- Department of Chemical and Biomolecular Engineering, Yonsei University, Seoul, South Korea
| | - Jinkee Hong
- Department of Chemical and Biomolecular Engineering, Yonsei University, Seoul, South Korea
| | - Martha Kim
- Department of Ophthalmology, Dongguk University, Ilsan Hospital, Goyang, South Korea
| | - Minwook Chang
- Department of Ophthalmology, Dongguk University, Ilsan Hospital, Goyang, South Korea
| | - Roy S Chuck
- Department of Ophthalmology and Visual Sciences, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York, United States
| | - Choul Yong Park
- Department of Ophthalmology, Dongguk University, Ilsan Hospital, Goyang, South Korea
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Abstract
In recent years, Acanthamoeba keratitis (AK) has became a clinically significant problem because of the broad use of contact lenses that are the major risk factor of the disease. The treatment presents considerable difficulties due to similarity of clinical manifestations of AK to other keratites (bacterial, herpetic, and fungal). This often leads to late diagnosis and formation of drug-resistant cysts. There is currently no specific drug universally suitable for monotherapy of AK. Instead, 2 agents (usually chlorhexidine and poligexametilen biguanide) are used that, if combined, are effective against both trophozoites and cysts. If necessary (severe keratitis, insufficient treatment effect), diamidines (propamidine and its analogs), antifungals (fluconazole, itrakonazol), certain antibiotics (Neomycinum), and iodine-containing medications (povidone-iodine) can be prescribed. The use of corticosteroids is considered unjustified because of the risk of rapid progression (due to disturbance of local immunity and also provocation of excystation of the amoebas). The penetrative keratoplasty may be required, especially if a descemetocele or corneal perforation occurs, however, its results are generally worse than those in other keratites because of a higher risk of complications (iridocyclitis, secondary glaucoma, AK recurrence in the graft). In some cases, good results are achieved with minimally invasive surgeries, such as mechanical epithelial debridement, conjunctivoplasty and cryopreserved amniotic membrane transplantation, excimer laser phototherapeutic keratectomy, and cross-linking. In the future, gene therapy and specific chemotherapy of AK may well be developed.
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Affiliation(s)
- N R Marchenko
- Research Institute of Eye Diseases, 11A, B Rossolimo St., Moscow, Russian Federation, 119021
| | - Evg A Kasparova
- Research Institute of Eye Diseases, 11A, B Rossolimo St., Moscow, Russian Federation, 119021
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Anti- Acanthamoeba activity of Tunisian Thymus capitatus essential oil and organic extracts. Exp Parasitol 2017; 183:231-235. [DOI: 10.1016/j.exppara.2017.09.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Revised: 08/10/2017] [Accepted: 09/11/2017] [Indexed: 01/25/2023]
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Abjani F, Khan NA, Jung SY, Siddiqui R. Status of the effectiveness of contact lens disinfectants in Malaysia against keratitis-causing pathogens. Exp Parasitol 2017; 183:187-193. [PMID: 28919333 DOI: 10.1016/j.exppara.2017.09.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Revised: 08/15/2017] [Accepted: 09/11/2017] [Indexed: 11/28/2022]
Abstract
The aim of this study was (i) to assess the antimicrobial effects of contact lens disinfecting solutions marketed in Malaysia against common bacterial eye pathogens and as well as eye parasite, Acanthamoeba castellanii, and (ii) to determine whether targeting cyst wall would improve the efficacy of contact lens disinfectants. Using ISO 14729 Stand-Alone Test for disinfecting solutions, bactericidal and amoebicidal assays of six different contact lens solutions including Oxysept®, AO SEPT PLUS, OPTI-FREE® pure moist®, Renu® fresh™, FreshKon® CLEAR and COMPLETE RevitaLens™ were performed using Manufacturers Minimum recommended disinfection time (MRDT). The efficacy of contact lens solutions was determined against keratitis-causing microbes, namely: Pseudomonas aeruginosa, Methicillin-resistant Staphylococcus aureus, Streptococcus pyogenes, Streptococcus pneumoniae, and Acanthamoeba castellanii. In addition, using chlorhexidine as an antiamoebic compound and cellulase enzyme to disrupt cyst wall structure, we determined whether combination of both agents can enhance efficacy of marketed contact lens disinfectants against A. castellanii trophozoites and cysts, in vitro. The results revealed that all contact lens disinfectants tested showed potent bactericidal effects exhibiting 100% kill against all bacterial species tested. In contrast, none of the contact lens disinfectants had potent effects against Acanthamoeba cysts viability. When tested against trophozoites, two disinfectants, Oxysept Multipurpose and AO-sept Multipurpose showed partial amoebicidal effects. Using chlorhexidine as an antiamoebic compound and cellulase enzyme to disrupt cyst wall structure, the findings revealed that combination of both agents in contact lens disinfectants abolished viability of A. castellanii cysts and trophozoites. Given the inefficacy of contact lens disinfectants tested in this study, these findings present a significant concern to public health. These findings revealed that targeting cyst wall by using cyst wall degrading molecules in contact lens disinfecting solutions will enhance their efficacy against this devastating eye infection.
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Affiliation(s)
- Farhat Abjani
- Department of Biological Sciences, School of Science and Technology, Sunway University, Malaysia
| | - Naveed Ahmed Khan
- Department of Biological Sciences, School of Science and Technology, Sunway University, Malaysia
| | - Suk Yul Jung
- Department of Biomedical Laboratory Science, Namseoul University, South Korea
| | - Ruqaiyyah Siddiqui
- Department of Biological Sciences, School of Science and Technology, Sunway University, Malaysia.
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Amoebicidal Activity of Caffeine and Maslinic Acid by the Induction of Programmed Cell Death in Acanthamoeba. Antimicrob Agents Chemother 2017; 61:AAC.02660-16. [PMID: 28320723 DOI: 10.1128/aac.02660-16] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Accepted: 03/12/2017] [Indexed: 01/07/2023] Open
Abstract
Free-living amoebae of the genus Acanthamoeba are the causal agents of a sight-threatening ulceration of the cornea called Acanthamoeba keratitis, as well as the rare but usually fatal disease granulomatous amoebic encephalitis. Although there are many therapeutic options for the treatment of Acanthamoeba infections, they are generally lengthy and/or have limited efficacy. For the best clinical outcome, treatments should target both the trophozoite and the cyst stages, as cysts are known to confer resistance to treatment. In this study, we document the activities of caffeine and maslinic acid against both the trophozoite and the cyst stages of three clinical strains of Acanthamoeba These drugs were chosen because they are reported to inhibit glycogen phosphorylase, which is required for encystation. Maslinic acid is also reported to be an inhibitor of extracellular proteases, which may be relevant since the protease activities of Acanthamoeba species are correlated with their pathogenicity. We also provide evidence for the first time that both drugs exert their anti-amoebal effects through programmed cell death.
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Carrijo-Carvalho LC, Sant'ana VP, Foronda AS, de Freitas D, de Souza Carvalho FR. Therapeutic agents and biocides for ocular infections by free-living amoebae of Acanthamoeba genus. Surv Ophthalmol 2016; 62:203-218. [PMID: 27836717 DOI: 10.1016/j.survophthal.2016.10.009] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Revised: 10/26/2016] [Accepted: 10/28/2016] [Indexed: 10/20/2022]
Abstract
Acanthamoeba keratitis is a sight-threatening infectious disease. Resistance of the cystic form of the protozoan to biocides and the potential toxicity of chemical compounds to corneal cells are the main concerns related to long-term treatment with the clinically available ophthalmic drugs. Currently, a limited number of recognized antimicrobial agents are available to treat ocular amoebic infections. Topical application of biguanide and diamidine antiseptic solutions is the first-line therapy. We consider the current challenges when treating Acanthamoeba keratitis and review the chemical properties, toxicities, and mechanisms of action of the available biocides. Antimicrobial therapy using anti-inflammatory drugs is controversial, and aspects related to this topic are discussed. Finally, we offer our perspective on potential improvement of the effectiveness and safety of therapeutic profiles, with the focus on the quality of life and the advancement of individualized medicine.
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Affiliation(s)
- Linda Christian Carrijo-Carvalho
- Department of Ophthalmology and Visual Sciences, Paulista School of Medicine, Federal University of São Paulo, São Paulo, Brazil
| | - Viviane Peracini Sant'ana
- Department of Ophthalmology and Visual Sciences, Paulista School of Medicine, Federal University of São Paulo, São Paulo, Brazil
| | - Annette Silva Foronda
- Department of Ophthalmology and Visual Sciences, Paulista School of Medicine, Federal University of São Paulo, São Paulo, Brazil
| | - Denise de Freitas
- Department of Ophthalmology and Visual Sciences, Paulista School of Medicine, Federal University of São Paulo, São Paulo, Brazil
| | - Fabio Ramos de Souza Carvalho
- Department of Ophthalmology and Visual Sciences, Paulista School of Medicine, Federal University of São Paulo, São Paulo, Brazil.
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Lorenzo-Morales J, Reyes-Batlle M, Sifaoui I, Arnalich-Montiel F, López-Arencibia A, Wagner C, Rocha-Cabrera P, del Castillo-Remiro A, Martínez-Carretero E, Piñero JE, Valladares B. Therapeutic targets and investigated treatment strategies inAcanthamoebakeratitis. Expert Opin Orphan Drugs 2016. [DOI: 10.1080/21678707.2016.1230060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Siddiqui R, Lakhundi S, Iqbal J, Khan NA. Effect of non-steroidal anti-inflammatory drugs on biological properties of Acanthamoeba castellanii belonging to the T4 genotype. Exp Parasitol 2016; 168:45-50. [PMID: 27381503 DOI: 10.1016/j.exppara.2016.06.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Accepted: 06/29/2016] [Indexed: 10/21/2022]
Abstract
Non-steroidal anti-inflammatory drug, Diclofenac, targeting COX have shown promise in the treatment of Acanthamoeba keratitis, but the underlying mechanisms remain unknown. Using various NSAIDs, Diclofenac sodium, Indomethacin, and Acetaminophen, here we determined the effects of NSAIDs on the biological properties of Acanthamoeba castellanii belonging to the T4 genotype. Using amoebicidal assays, the results revealed that Diclofenac sodium, and Indomethacin affected growth of A. castellanii. In contrast, none of the compounds tested had any effect on the viability of A. castellanii. Importantly, all NSAIDs tested abolished A. castellanii encystation. This is a significant finding as the ability of amoebae to transform into the dormant cyst form presents a significant challenge in the successful treatment of infection. The NSAIDs inhibit production of cyclo-oxegenase, which regulates the synthesis of prostaglandins suggesting that cyclooxygenases (COX-1 and COX-2) and prostaglandins play significant role(s) in Acanthamoeba biology. As NSAIDs are routinely used in the clinical practice, these findings may help design improved preventative strategies and/or of therapeutic value to improve prognosis, when used in combination with other anti-amoebic drugs.
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Affiliation(s)
- Ruqaiyyah Siddiqui
- Department of Biological Sciences, Faculty of Science and Technology, Sunway University, Selangor, Malaysia
| | - Sahreena Lakhundi
- Department of Biological and Biomedical Sciences, Aga Khan University, Karachi, Pakistan
| | - Junaid Iqbal
- Division of Pediatric Infectious Diseases, Vanderbilt University School of Medicine, Nashville, USA
| | - Naveed Ahmed Khan
- Department of Biological Sciences, Faculty of Science and Technology, Sunway University, Selangor, Malaysia.
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Aqeel Y, Siddiqui R, Manan Z, Khan NA. The role of G protein coupled receptor-mediated signaling in the biological properties of Acanthamoeba castellanii of the T4 genotype. Microb Pathog 2015; 81:22-7. [DOI: 10.1016/j.micpath.2015.03.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Revised: 03/07/2015] [Accepted: 03/09/2015] [Indexed: 12/21/2022]
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Photochemotherapeutic strategy against Acanthamoeba infections. Antimicrob Agents Chemother 2015; 59:3031-41. [PMID: 25753633 DOI: 10.1128/aac.05126-14] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Accepted: 03/02/2015] [Indexed: 12/16/2022] Open
Abstract
Acanthamoeba is a protist pathogen that can cause serious human infections, including blinding keratitis and a granulomatous amoebic encephalitis that almost always results in death. The current treatment for these infections includes a mixture of drugs, and even then, a recurrence can occur. Photochemotherapy has shown promise in the treatment of Acanthamoeba infections; however, the selective targeting of pathogenic Acanthamoeba has remained a major concern. The mannose-binding protein is an important adhesin expressed on the surface membranes of pathogenic Acanthamoeba organisms. To specifically target Acanthamoeba, the overall aim of this study was to synthesize a photosensitizing compound (porphyrin) conjugated with mannose and test its efficacy in vitro. The synthesis of mannose-conjugated porphyrin was achieved by mixing benzaldehyde and pyrrole, yielding tetraphenylporphyrin. Tetraphenylporphyrin was then converted into mono-nitrophenylporphyrin by selectively nitrating the para position of the phenyl rings, as confirmed by nuclear magnetic resonance (NMR) spectroscopy. The mono-nitrophenylporphyrin was reduced to mono-aminophenylporphyrin in the presence of tin dichloride and confirmed by a peak at m/z 629. Finally, mono-aminoporphyrin was conjugated with mannose, resulting in the formation of an imine bond. Mannose-conjugated porphyrin was confirmed through spectroscopic analysis and showed that it absorbed light of wavelengths ranging from 425 to 475 nm. To determine the antiacanthamoebic effects of the derived product, amoebae were incubated with mannose-conjugated porphyrin for 1 h and washed 3 times to remove extracellular compound. Next, the amoebae were exposed to light of the appropriate wavelength for 1 h. The results revealed that mannose-conjugated porphyrin produced potent trophicidal effects and blocked excystation. In contrast, Acanthamoeba castellanii incubated with mannose alone and porphyrin alone did not exhibit an antiamoebic effect. Consistently, pretreatment with mannose-conjugated porphyrin reduced the A. castellanii-mediated host cell cytotoxicity from 97% to 4.9%. In contrast, treatment with porphyrin, mannose, or solvent alone had no protective effects on the host cells. These data suggest that mannose-conjugated porphyrin has application for the targeted photodynamic therapy of Acanthamoeba infections and may serve as a model in the development of therapeutic interventions against other eukaryotic infections.
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Statins and voriconazole induce programmed cell death in Acanthamoeba castellanii. Antimicrob Agents Chemother 2015; 59:2817-24. [PMID: 25733513 DOI: 10.1128/aac.00066-15] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Accepted: 02/25/2015] [Indexed: 12/11/2022] Open
Abstract
Members of the genus Acanthamoeba are facultative pathogens of humans, causing a sight-threatening keratitis and a life-threatening encephalitis. In order to treat those infections properly, it is necessary to target the treatment not only to the trophozoite but also to the cyst. Furthermore, it may be advantageous to avoid parasite killing by necrosis, which may induce local inflammation. We must also avoid toxicity of host tissue. Many drugs which target eukaryotes are known to induce programmed cell death (PCD), but this process is poorly characterized in Acanthamoeba. Here, we study the processes of programmed cell death in Acanthamoeba, induced by several drugs, such as statins and voriconazole. We tested atorvastatin, fluvastatin, simvastatin, and voriconazole at the 50% inhibitory concentrations (IC50s) and IC90s that we have previously established. In order to evaluate this phenomenon, we investigated the DNA fragmentation, one of the main characteristics of PCD, with quantitative and qualitative techniques. Also, the changes related to phosphatidylserine exposure on the external cell membrane and cell permeability were studied. Finally, because caspases are key to PCD pathways, caspase activity was evaluated in Acanthamoeba. All the drugs assayed in this study induced PCD in Acanthamoeba. To the best of our knowledge, this is the first study where PCD induced by drugs is described quantitatively and qualitatively in Acanthamoeba.
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Lorenzo-Morales J, Khan NA, Walochnik J. An update on Acanthamoeba keratitis: diagnosis, pathogenesis and treatment. ACTA ACUST UNITED AC 2015; 22:10. [PMID: 25687209 PMCID: PMC4330640 DOI: 10.1051/parasite/2015010] [Citation(s) in RCA: 438] [Impact Index Per Article: 48.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Accepted: 02/06/2015] [Indexed: 12/21/2022]
Abstract
Free-living amoebae of the genus Acanthamoeba are causal agents of a severe sight-threatening infection of the cornea known as Acanthamoeba keratitis. Moreover, the number of reported cases worldwide is increasing year after year, mostly in contact lens wearers, although cases have also been reported in non-contact lens wearers. Interestingly, Acanthamoeba keratitis has remained significant, despite our advances in antimicrobial chemotherapy and supportive care. In part, this is due to an incomplete understanding of the pathogenesis and pathophysiology of the disease, diagnostic delays and problems associated with chemotherapeutic interventions. In view of the devastating nature of this disease, here we present our current understanding of Acanthamoeba keratitis and molecular mechanisms associated with the disease, as well as virulence traits of Acanthamoeba that may be potential targets for improved diagnosis, therapeutic interventions and/or for the development of preventative measures. Novel molecular approaches such as proteomics, RNAi and a consensus in the diagnostic approaches for a suspected case of Acanthamoeba keratitis are proposed and reviewed based on data which have been compiled after years of working on this amoebic organism using many different techniques and listening to many experts in this field at conferences, workshops and international meetings. Altogether, this review may serve as the milestone for developing an effective solution for the prevention, control and treatment of Acanthamoeba infections.
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Affiliation(s)
- Jacob Lorenzo-Morales
- University Institute of Tropical Diseases and Public Health of the Canary Islands, University of La Laguna, Avda. Astrofísico Fco. Sánchez, S/N, 38203 La Laguna, Tenerife, Canary Islands, Spain
| | - Naveed A Khan
- Department of Biological and Biomedical Sciences, Aga Khan University, Karachi, Pakistan
| | - Julia Walochnik
- Institute of Specific Prophylaxis and Tropical Medicine, Medical University of Vienna, Vienna, Austria
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Antibacterial activity of THAM Trisphenylguanide against methicillin-resistant Staphylococcus aureus. PLoS One 2014; 9:e97742. [PMID: 24840307 PMCID: PMC4026384 DOI: 10.1371/journal.pone.0097742] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2013] [Accepted: 04/24/2014] [Indexed: 11/19/2022] Open
Abstract
This study investigated the potential antibacterial activity of three series of compounds synthesized from 12 linear and branched polyamines with 2–8 amino groups, which were substituted to produce the corresponding guanides, biguanides, or phenylguanides, against Acinetobacter baumannii, Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus. Antibacterial activity was measured for each compound by determining the minimum inhibitory concentration against the bacteria, and the toxicity towards mammalian cells was determined. The most effective compound, THAM trisphenylguanide, was studied in time-to-kill and cytoplasmic leakage assays against methicillin-resistant Staphylococcus aureus (MRSA, USA300) in comparison to chlorhexidine. Preliminary toxicity and MRSA challenge studies in mice were also conducted on this compound. THAM trisphenylguanide showed significant antibacterial activity (MIC ∼1 mg/L) and selectivity against MRSA relative to all the other bacteria examined. In time-to-kill assays it showed increased antimicrobial activity against MRSA versus chlorhexidine. It induced leakage of cytoplasmic content at concentrations that did not reduce cell viability, suggesting the mechanism of action may involve membrane disruption. Using an intraperitoneal mouse model of invasive MRSA disease, THAM trisphenylguanide reduced bacterial burden locally and in deeper tissues. This study has identified a novel guanide compound with selective microbicidal activity against Staphylococcus aureus, including a methicillin-resistant (MRSA) strain.
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Lloyd D. Encystment in Acanthamoeba castellanii: a review. Exp Parasitol 2014; 145 Suppl:S20-7. [PMID: 24726698 DOI: 10.1016/j.exppara.2014.03.026] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Revised: 03/02/2014] [Accepted: 03/04/2014] [Indexed: 10/25/2022]
Abstract
Differentiation of Acanthamoeba castellanii trophozoites involves massive turnover of cellular components and remodelling of organelle structure and function so as to produce a cryptobiotic cell, resistant to desiccation, heat, freezing, and chemical treatments. This review presents a summary of a decade of research on the most studied aspects of the biochemistry of this process, with emphasis on problems of biocide and drug resistances, putative new targets, molecular and cell biology of the process of encystment, and the characteristics of the encysted state. As well as the intrinsic pathogenicity of the organism towards the cornea, and the ability of related species to invade the human brain, its propensity for harbouring and transmitting pathogenic bacteria and viruses is considerable and leads to increasing concerns. The long-term survival and resistance of cysts to drugs and biocides adds another layer of complexity to the problem of their elimination.
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Affiliation(s)
- David Lloyd
- School of Biosciences, Cardiff University, Cardiff, Wales CF10 3AT, UK.
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Khan NA, Siddiqui R. War on terror cells: killing the host that harbours 'superbugs' is an infection control strategy in our fight against infectious diseases. Pathog Glob Health 2014; 108:4-10. [PMID: 24548155 DOI: 10.1179/2047773213y.0000000125] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
It is proposed that targeting the environmental host that harbour 'superbugs' is an effective strategy in our fight against infectious diseases.
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Evaluation of the in vitro activity of commercially available moxifloxacin and voriconazole eye-drops against clinical strains of Acanthamoeba. Graefes Arch Clin Exp Ophthalmol 2013; 251:2111-7. [DOI: 10.1007/s00417-013-2371-y] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2013] [Revised: 04/08/2013] [Accepted: 04/25/2013] [Indexed: 10/26/2022] Open
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29
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SHIRAI AKIHIRO, ENDO TOSHIYUKI, MASEDA HIDEAKI, OMASA TAKESHI. Synthesis of Thiazole Derivatives and Evaluation of Their Antiamoebic Activity and Cytotoxicity. Biocontrol Sci 2013; 18:183-91. [DOI: 10.4265/bio.18.183] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
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30
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Jiang Z, Wang B, Che H, Liu B. Structural Characterization and Bacteriostatic and Cytotoxicity to 3T3 Cells Study of Oligobiguanidine (Polyhexamethylene Biguanidine Hydrochloride) and its 3-Glycidoxypropyltrimethoxysilane Derivatives. JOURNAL OF MACROMOLECULAR SCIENCE PART A-PURE AND APPLIED CHEMISTRY 2012. [DOI: 10.1080/10601325.2012.722856] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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31
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Thomas V, McDonnell G, Denyer SP, Maillard JY. Free-living amoebae and their intracellular pathogenic microorganisms: risks for water quality. FEMS Microbiol Rev 2010; 34:231-59. [DOI: 10.1111/j.1574-6976.2009.00190.x] [Citation(s) in RCA: 208] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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32
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Acanthamoeba castellanii: proteins involved in actin dynamics, glycolysis, and proteolysis are regulated during encystation. Exp Parasitol 2009; 123:90-4. [PMID: 19523468 DOI: 10.1016/j.exppara.2009.06.006] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2009] [Revised: 05/13/2009] [Accepted: 06/04/2009] [Indexed: 11/21/2022]
Abstract
Acanthamoeba castellanii is a pathogenic free-living amoeba. Cyst forms are particularly important in their pathogenicity, as they are more resistant to treatments and might protect pathogenic intracellular bacteria. However, encystation is poorly understood at the molecular level and global changes at the protein level have not been completely described. In this study, we performed two-dimensional gel electrophoresis to compare protein expression in trophozoite and cyst forms. Four proteins, specifically expressed in trophozoites, and four proteins, specifically expressed in cysts, were identified. Two proteins, enolase and fructose bisphosphate aldolase, are involved in the glycolytic pathway. Three proteins are likely actin-binding proteins, which is consistent with the dramatic morphological modifications of the cells during encystation. One protein belongs to the serine protease family and has been already linked to encystation in A. castellanii. In conclusion, this study found that the proteins whose expression was modified during encystation were likely involved in actin dynamics, glycolysis, and proteolysis.
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Kilvington S, Lonnen J. A comparison of regimen methods for the removal and inactivation of bacteria, fungi and Acanthamoeba from two types of silicone hydrogel lenses. Cont Lens Anterior Eye 2009; 32:73-7. [DOI: 10.1016/j.clae.2008.12.008] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2008] [Revised: 10/30/2008] [Accepted: 12/06/2008] [Indexed: 11/28/2022]
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34
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Glycogen phosphorylase in Acanthamoeba spp.: determining the role of the enzyme during the encystment process using RNA interference. EUKARYOTIC CELL 2008; 7:509-17. [PMID: 18223117 DOI: 10.1128/ec.00316-07] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Acanthamoeba infections are difficult to treat due to often late diagnosis and the lack of effective and specific therapeutic agents. The most important reason for unsuccessful therapy seems to be the existence of a double-wall cyst stage that is highly resistant to the available treatments, causing reinfections. The major components of the Acanthamoeba cyst wall are acid-resistant proteins and cellulose. The latter has been reported to be the major component of the inner cyst wall. It has been demonstrated previously that glycogen is the main source of free glucose for the synthesis of cellulose in Acanthamoeba, partly as glycogen levels fall during the encystment process. In other lower eukaryotes (e.g., Dictyostelium discoideum), glycogen phosphorylase has been reported to be the main tool used for glycogen breakdown in order to maintain the free glucose levels during the encystment process. Therefore, it was hypothesized that the regulation of the key processes involved in the Acanthamoeba encystment may be similar to the previously reported regulation mechanisms in other lower eukaryotes. The catalytic domain of the glycogen phosphorylase was silenced using RNA interference methods, and the effect of this phenomenon was assessed by light and electron microscopy analyses, calcofluor staining, expression zymogram assays, and Northern and Western blot analyses of both small interfering RNA-treated and control cells. The present report establishes the role of glycogen phosphorylase during the encystment process of Acanthamoeba. Moreover, the obtained results demonstrate that the enzyme is required for cyst wall assembly, mainly for the formation of the cell wall inner layer.
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