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Thomas L, Khan NA, Siddiqui R, Alawfi BS, Lloyd D. Cell death of Acanthamoeba castellanii following exposure to antimicrobial agents commonly included in contact lens disinfecting solutions. Parasitol Res 2023; 123:16. [PMID: 38060008 DOI: 10.1007/s00436-023-08061-5] [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: 09/11/2023] [Accepted: 10/27/2023] [Indexed: 12/08/2023]
Abstract
Several antimicrobial agents are commonly included in contact lens disinfectant solutions including chlorhexidine diacetate (CHX), polyhexamethylene biguanide (PHMB) or myristamidopropyl dimethylamine (MAPD); however, their mode of action, i.e. necrosis versus apoptosis is incompletely understood. Here, we determined whether a mechanism of cell death resembling that of apoptosis was present in Acanthamoeba castellanii of the T4 genotype (NEFF) following exposure to the aforementioned antimicrobials using the anticoagulant annexin V that undergoes rapid high affinity binding to phosphatidylserine in the presence of calcium, making it a sensitive probe for phosphatidylserine exposure. The results revealed that under the conditions employed in this study, an apoptotic pathway of cell death in this organism at the tested conditions does not occur. Our findings suggest that necrosis is the likely mode of action; however, future mechanistic studies should be accomplished in additional experimental conditions to further comprehend the molecular mechanisms of cell death in Acanthamoeba.
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Affiliation(s)
- Louise Thomas
- Microbiology Research, School of Biosciences, Cardiff University, P. O. Box 915, Cardiff, CF10 3AX, UK
| | - Naveed Ahmed Khan
- Microbiota Research Center, Istinye University, 34010, Istanbul, Turkey.
| | - Ruqaiyyah Siddiqui
- Microbiota Research Center, Istinye University, 34010, Istanbul, Turkey
- Institute of Biological Chemistry, Biophysics and Bioengineering, Heriot-Watt University Edinburgh, Edinburgh, EH14 4AS, UK
| | - Bader S Alawfi
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Taibah University, Madinah, 42353, Saudi Arabia
| | - David Lloyd
- Microbiology Research, School of Biosciences, Cardiff University, P. O. Box 915, Cardiff, CF10 3AX, UK.
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Rodríguez-Expósito RL, Sifaoui I, Reyes-Batlle M, Fuchs F, Scheid PL, Piñero JE, Sutak R, Lorenzo-Morales J. Induction of Programmed Cell Death in Acanthamoeba culbertsoni by the Repurposed Compound Nitroxoline. Antioxidants (Basel) 2023; 12:2081. [PMID: 38136200 PMCID: PMC10740438 DOI: 10.3390/antiox12122081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 11/22/2023] [Accepted: 12/04/2023] [Indexed: 12/24/2023] Open
Abstract
Acanthamoeba is a ubiquitous genus of amoebae that can act as opportunistic parasites in both humans and animals, causing a variety of ocular, nervous and dermal pathologies. Despite advances in Acanthamoeba therapy, the management of patients with Acanthamoeba infections remains a challenge for health services. Therefore, there is a need to search for new active substances against Acanthamoebae. In the present study, we evaluated the amoebicidal activity of nitroxoline against the trophozoite and cyst stages of six different strains of Acanthamoeba. The strain A. griffini showed the lowest IC50 value in the trophozoite stage (0.69 ± 0.01 µM), while the strain A. castellanii L-10 showed the lowest IC50 value in the cyst stage (0.11 ± 0.03 µM). In addition, nitroxoline induced in treated trophozoites of A. culbertsoni features compatibles with apoptosis and autophagy pathways, including chromatin condensation, mitochondrial malfunction, oxidative stress, changes in cell permeability and the formation of autophagic vacuoles. Furthermore, proteomic analysis of the effect of nitroxoline on trophozoites revealed that this antibiotic induced the overexpression and the downregulation of proteins involved in the apoptotic process and in metabolic and biosynthesis pathways.
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Affiliation(s)
- Rubén L. Rodríguez-Expósito
- Instituto Universitario de Enfermedades Tropicales y Salud Pública de Canarias (IUETSPC), Universidad de La Laguna (ULL), Avda. Astrofísico Fco. Sánchez, S/N, 38203 San Cristóbal de La Laguna, Spain; (R.L.R.-E.); (I.S.); (M.R.-B.)
- Departamento de Obstetricia y Ginecología, Pediatría, Medicina Preventiva y Salud Pública, Toxicología, Medicina Legal y Forense y Parasitología, Universidad de La Laguna, 38203 San Cristóbal de La Laguna, Spain
| | - Ines Sifaoui
- Instituto Universitario de Enfermedades Tropicales y Salud Pública de Canarias (IUETSPC), Universidad de La Laguna (ULL), Avda. Astrofísico Fco. Sánchez, S/N, 38203 San Cristóbal de La Laguna, Spain; (R.L.R.-E.); (I.S.); (M.R.-B.)
- Departamento de Obstetricia y Ginecología, Pediatría, Medicina Preventiva y Salud Pública, Toxicología, Medicina Legal y Forense y Parasitología, Universidad de La Laguna, 38203 San Cristóbal de La Laguna, Spain
| | - María Reyes-Batlle
- Instituto Universitario de Enfermedades Tropicales y Salud Pública de Canarias (IUETSPC), Universidad de La Laguna (ULL), Avda. Astrofísico Fco. Sánchez, S/N, 38203 San Cristóbal de La Laguna, Spain; (R.L.R.-E.); (I.S.); (M.R.-B.)
- Departamento de Obstetricia y Ginecología, Pediatría, Medicina Preventiva y Salud Pública, Toxicología, Medicina Legal y Forense y Parasitología, Universidad de La Laguna, 38203 San Cristóbal de La Laguna, Spain
| | - Frieder Fuchs
- Institute for Medical Microbiology, Immunology and Hygiene, University Hospital Cologne, Faculty of Medicine, University of Cologne, 50935 Cologne, Germany;
- Department of Microbiology and Hospital Hygiene, Bundeswehr Central Hospital Koblenz, 56072 Koblenz, Germany
| | - Patrick L. Scheid
- Parasitology Lab., Central Military Hospital Koblenz, 56072 Koblenz, Germany
- Department of Biology, Working Group Parasitology and Infection Biology, University Koblenz, 56070 Koblenz, Germany
| | - José E. Piñero
- Instituto Universitario de Enfermedades Tropicales y Salud Pública de Canarias (IUETSPC), Universidad de La Laguna (ULL), Avda. Astrofísico Fco. Sánchez, S/N, 38203 San Cristóbal de La Laguna, Spain; (R.L.R.-E.); (I.S.); (M.R.-B.)
- Departamento de Obstetricia y Ginecología, Pediatría, Medicina Preventiva y Salud Pública, Toxicología, Medicina Legal y Forense y Parasitología, Universidad de La Laguna, 38203 San Cristóbal de La Laguna, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III, 28220 Madrid, Spain
| | - Robert Sutak
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, 252 50 Vestec, Czech Republic
| | - Jacob Lorenzo-Morales
- Instituto Universitario de Enfermedades Tropicales y Salud Pública de Canarias (IUETSPC), Universidad de La Laguna (ULL), Avda. Astrofísico Fco. Sánchez, S/N, 38203 San Cristóbal de La Laguna, Spain; (R.L.R.-E.); (I.S.); (M.R.-B.)
- Departamento de Obstetricia y Ginecología, Pediatría, Medicina Preventiva y Salud Pública, Toxicología, Medicina Legal y Forense y Parasitología, Universidad de La Laguna, 38203 San Cristóbal de La Laguna, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III, 28220 Madrid, Spain
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3
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Goyal N, Barai A, Sen S, Kondabagil K. Amoebal Tubulin Cleavage Late during Infection Is a Characteristic Feature of Mimivirus but Not of Marseillevirus. Microbiol Spectr 2022; 10:e0275322. [PMID: 36453900 PMCID: PMC9769910 DOI: 10.1128/spectrum.02753-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 11/04/2022] [Indexed: 12/03/2022] Open
Abstract
Mimivirus and Marseillevirus infections of Acanthamoeba castellanii, like most other viral infections, induce cytopathic effects (CPE). The details of how they bring about CPE and to what extent and how they modify the host cytoskeletal network are unclear. In this study, we compared the rearrangement of the host cytoskeletal network induced by Mimivirus and Marseillevirus upon infection. We show that while both Mimivirus and Marseillevirus infections of A. castellanii cells cause retraction of acanthopodia and depolymerization of the host actin filament network, the Mimivirus infection also results in characteristic cleavage of the host tubulin, a phenomenon not previously reported with any intracellular pathogens. Furthermore, we show that the amoebal tubulin cleavage during Mimivirus infection is a post-replicative event. Because time-lapse microscopy showed that Mimivirus infection leads to the bursting of cells, releasing the virus, we hypothesize that tubulin cleavage together with actin depolymerization during the later stages of Mimivirus assembly is essential for cell lysis due to apoptotic/necrotic cell death. We also characterize the Mimivirus-encoded gp560, a Zn metalloprotease, however, the purified gp560 protein was unable to cleave the commercially available porcine brain tubulin. While protein synthesis is essential for causing the morphological changes in the case of Mimivirus, the proteins which are packaged in the viral capsid along with the genome are sufficient to induce CPE in the case of Marseillevirus. IMPORTANCE In general, intracellular pathogens target the cytoskeletal network to enable their life cycle inside the host. Pathogen-induced changes in the host cell morphology usually accompany global changes in the cytoskeleton resulting in cytopathic effects. While viruses have been shown to use the host actin cytoskeleton for entry and transport during early infection, the role of microtubules in the viral life cycle is only beginning to emerge. Here, we show that the giant viruses Mimivirus and Marseillevirus both induce depolymerization of the actin filament, Mimivirus also causes a characteristic cleavage of tubulin not previously reported for any intracellular pathogen. Because tubulin cleavage occurs late during infection, we hypothesize that tubulin cleavage aids in cell death and lysis rather than establishing infection. The different strategies used by viruses with similar host niches may help them survive in competition.
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Affiliation(s)
- Nisha Goyal
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, India
| | - Amlan Barai
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, India
| | - Shamik Sen
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, India
| | - Kiran Kondabagil
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, India
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4
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Rodríguez-Expósito RL, Sosa-Rueda J, Reyes-Batlle M, Sifaoui I, Cen-Pacheco F, Daranas AH, Díaz-Marrero AR, Piñero JE, Fernández JJ, Lorenzo-Morales J. Antiamoeboid activity of squamins C-F, cyclooctapeptides from Annona globifora. INTERNATIONAL JOURNAL FOR PARASITOLOGY-DRUGS AND DRUG RESISTANCE 2021; 17:67-79. [PMID: 34411895 PMCID: PMC8377437 DOI: 10.1016/j.ijpddr.2021.08.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 08/03/2021] [Accepted: 08/09/2021] [Indexed: 11/17/2022]
Abstract
Free-living amoebae of Acanthamoeba spp. are causative agents of human infections such as granulomatous amoebic encephalitis (GAE) and Acanthamoeba keratitis (AK). The exploration of innovative chemical entities from natural sources that induce intrinsic apoptotic pathway or a Programmed Cell Death (PCD) in Acanthamoeba protozoa is essential to develop new therapeutic strategies. In this work, the antiamoeboid activity of squamins C-F (1-4), four cyclooctapeptides isolated from Annona globiflora was tested in vitro against Acanthamoeba castellanii Neff, A. polyphaga, A. quina, and A. griffini, and a structure-activity relationship was also established. The most sensitive strain against all tested cyclooctapeptides was A. castellanii Neff being the R conformers of the S-oxo-methionine residue, squamins D (2) and F (4), the most active against the trophozoite stage. It is remarkable that all four peptides showed no cytotoxic effects against murine macrophages cell line J774A.1. The analysis of the mode of action of squamins C-F against A. castellanii indicate that these cyclopeptides induced the mechanisms of programmed cell death (PCD). All peptides trigger mitochondrial damages, significant inhibition of ATP production compared to the negative control, chromatin condensation and slight damages in membrane that affects its permeability despite it conserves integrity at the IC90 for 24 h. An increase in reactive oxygen species (ROS) was observed in all cases.
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Affiliation(s)
- Rubén L Rodríguez-Expósito
- Instituto Universitario de Enfermedades Tropicales y Salud Pública de Canarias (IUETSPC), Universidad de La Laguna (ULL), Avda. Astrofísico Francisco Sánchez s/n, 38203, La Laguna, Tenerife, Spain; Departamento de Obstetricia, Ginecología, Pediatría, Medicina Preventiva y Salud Pública, Toxicología, Medicina Legal y Forense y Parasitología, Universidad de La Laguna, 38203, La Laguna, Tenerife, Spain; Red de Investigación Cooperativa en Enfermedades Tropicales (RICET), Madrid, Spain
| | - Javier Sosa-Rueda
- Facultad de Bioanálisis, Universidad Veracruzana (UV), Agustín de Iturbide s/n, Centro, 91700Veracruz, Veracruz, Mexico
| | - María Reyes-Batlle
- Instituto Universitario de Enfermedades Tropicales y Salud Pública de Canarias (IUETSPC), Universidad de La Laguna (ULL), Avda. Astrofísico Francisco Sánchez s/n, 38203, La Laguna, Tenerife, Spain; Departamento de Obstetricia, Ginecología, Pediatría, Medicina Preventiva y Salud Pública, Toxicología, Medicina Legal y Forense y Parasitología, Universidad de La Laguna, 38203, La Laguna, Tenerife, Spain; Red de Investigación Cooperativa en Enfermedades Tropicales (RICET), Madrid, Spain
| | - Ines Sifaoui
- Instituto Universitario de Enfermedades Tropicales y Salud Pública de Canarias (IUETSPC), Universidad de La Laguna (ULL), Avda. Astrofísico Francisco Sánchez s/n, 38203, La Laguna, Tenerife, Spain; Departamento de Obstetricia, Ginecología, Pediatría, Medicina Preventiva y Salud Pública, Toxicología, Medicina Legal y Forense y Parasitología, Universidad de La Laguna, 38203, La Laguna, Tenerife, Spain; Red de Investigación Cooperativa en Enfermedades Tropicales (RICET), Madrid, Spain
| | - Francisco Cen-Pacheco
- Instituto Universitario de Bio-Orgánica Antonio González (IUBO AG), Universidad de La Laguna (ULL), Avda. Astrofísico Francisco Sánchez 2, 38206, La Laguna, Tenerife, Spain; Facultad de Bioanálisis, Universidad Veracruzana (UV), Agustín de Iturbide s/n, Centro, 91700Veracruz, Veracruz, Mexico.
| | - Antonio Hernández Daranas
- Instituto de Productos Naturales y Agrobiología (IPNA), Consejo Superior de Investigaciones Científicas (CSIC), Avda. Astrofísico Francisco Sánchez 3, 38206, La Laguna, Tenerife, Spain
| | - Ana R Díaz-Marrero
- Instituto Universitario de Bio-Orgánica Antonio González (IUBO AG), Universidad de La Laguna (ULL), Avda. Astrofísico Francisco Sánchez 2, 38206, La Laguna, Tenerife, Spain
| | - José E Piñero
- Instituto Universitario de Enfermedades Tropicales y Salud Pública de Canarias (IUETSPC), Universidad de La Laguna (ULL), Avda. Astrofísico Francisco Sánchez s/n, 38203, La Laguna, Tenerife, Spain; Departamento de Obstetricia, Ginecología, Pediatría, Medicina Preventiva y Salud Pública, Toxicología, Medicina Legal y Forense y Parasitología, Universidad de La Laguna, 38203, La Laguna, Tenerife, Spain; Red de Investigación Cooperativa en Enfermedades Tropicales (RICET), Madrid, Spain.
| | - José J Fernández
- Instituto Universitario de Bio-Orgánica Antonio González (IUBO AG), Universidad de La Laguna (ULL), Avda. Astrofísico Francisco Sánchez 2, 38206, La Laguna, Tenerife, Spain; Departamento de Química Orgánica, Universidad de La Laguna (ULL), Avda. Astrofísico Francisco Sánchez s/n, 38206, La Laguna, Tenerife, Spain.
| | - Jacob Lorenzo-Morales
- Instituto Universitario de Enfermedades Tropicales y Salud Pública de Canarias (IUETSPC), Universidad de La Laguna (ULL), Avda. Astrofísico Francisco Sánchez s/n, 38203, La Laguna, Tenerife, Spain; Departamento de Obstetricia, Ginecología, Pediatría, Medicina Preventiva y Salud Pública, Toxicología, Medicina Legal y Forense y Parasitología, Universidad de La Laguna, 38203, La Laguna, Tenerife, Spain; Red de Investigación Cooperativa en Enfermedades Tropicales (RICET), Madrid, Spain.
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5
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Mungroo MR, Khan NA, Anwar A, Siddiqui R. Nanovehicles in the improved treatment of infections due to brain-eating amoebae. Int Microbiol 2021; 25:225-235. [PMID: 34368912 DOI: 10.1007/s10123-021-00201-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 07/07/2021] [Accepted: 08/02/2021] [Indexed: 01/02/2023]
Abstract
Pathogenic free-living amoebae are known to cause fatal central nervous system infections with extremely high mortality rates. High selectivity of the blood-brain barrier hampers delivery of drugs and untargeted delivery of drugs can cause severe side effects. Nanovehicles can be used for targeted drug delivery across the blood-brain barrier. Inorganic nanoparticles have been explored as carriers for various biomedical applications and can be modified with various ligands for efficient targeting and cell selectivity while lipid-based nanoparticles have been extensively used in the development of both precision and colloidal nanovehicles. Nanomicelles and polymeric nanoparticles can also serve as nanocarriers and may be modified so that responsiveness of the nanoparticles and release of the loads are linked to specific stimuli. These nanoparticles are discussed here in the context of the treatment of central nervous system infections due to pathogenic amoebae. It is anticipated that these novel strategies can be utilized in tandem with novel drug leads currently in the pipeline and yield in the development of much needed treatments against these devastating parasites.
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Affiliation(s)
- Mohammad Ridwane Mungroo
- Department of Clinical Sciences, College of Medicine, University of Sharjah, 27272, Sharjah, United Arab Emirates
| | - Naveed Ahmed Khan
- Department of Clinical Sciences, College of Medicine, University of Sharjah, 27272, Sharjah, United Arab Emirates.
| | - Ayaz Anwar
- Department of Biological Sciences, School of Medical and Life Sciences, Sunway University, Subang Jaya 47500, Selangor, Malaysia
| | - Ruqaiyyah Siddiqui
- College of Arts and Sciences, American University of Sharjah, 26666, Sharjah, United Arab Emirates
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Antiamoebic effects of sesquiterpene lactones isolated from the zoanthid Palythoa aff. clavata. Bioorg Chem 2021; 108:104682. [PMID: 33556696 DOI: 10.1016/j.bioorg.2021.104682] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 01/19/2021] [Accepted: 01/20/2021] [Indexed: 12/22/2022]
Abstract
Opportunistic parasitic protozoa of genus Acanthamoeba are responsible to cause severe infections in humans such as Acanthamoeba Keratitis or Amoebic Granulomatous Encephalitis. Current treatments are usually toxic and inefficient and there is a need to access new therapeutic agents. The antiamoebic effects of nephthediol (1) and fourteen germacranolide and eudesmanolide sesquiterpene lactones (2-5, 7-12) isolated from the indigenous zoanthid Palythoa aff. clavata collected at the coast of Lanzarote, Canary Islands were studied against Acanthamoeba castellanii Neff, and the clinical strains A. polyphaga and A. griffini. 4-epi-arbusculin A (11) presented the lowest IC50 value (26,47 ± 1,69 µM) against A. castellanii Neff and low cytotoxicity against murine macrophages, followed by isobadgerin (2), which also showed to be active against A. castellanii Neff cysts. The studies on the mode of action of compounds 2 and 11 revealed these sesquiterpene lactones induce mechanisms of PDC on A. castellanii Neff.
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7
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Lacerda AG, Lira M. Acanthamoeba
keratitis: a review of biology, pathophysiology and epidemiology. Ophthalmic Physiol Opt 2020; 41:116-135. [DOI: 10.1111/opo.12752] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 09/07/2020] [Accepted: 09/09/2020] [Indexed: 01/13/2023]
Affiliation(s)
| | - Madalena Lira
- Centre of Physics University of Minho Braga Portugal
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8
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Anwar A, Khan NA, Siddiqui R. Repurposing of Drugs Is a Viable Approach to Develop Therapeutic Strategies against Central Nervous System Related Pathogenic Amoebae. ACS Chem Neurosci 2020; 11:2378-2384. [PMID: 32073257 DOI: 10.1021/acschemneuro.9b00613] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Brain-eating amoebae including Acanthamoeba spp., Naegleria fowleri, and Balamuthia mandrillaris cause rare infections of the central nervous system that almost always result in death. The high mortality rate, lack of interest for drug development from pharmaceutical industries, and no available effective drugs present an alarming challenge. The current drugs employed in the management and therapy of these devastating diseases are amphotericin B, miltefosine, chlorhexidine, pentamidine, and voriconazole which are generally used in combination. However, clinical evidence shows that these drugs have limited efficacy and high host cell cytotoxicity. Repurposing of drugs is a practical approach to utilize commercially available, U.S. Food and Drug Administration approved drugs for one disease against rare diseases caused by brain-eating amoebae. In this Perspective, we highlight some of the success stories of drugs repositioned against neglected parasitic diseases and identify future potential for effective and sustainable drug development against brain-eating amoebae infections.
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Affiliation(s)
- Ayaz Anwar
- Department of Biological Sciences, School of Science and Technology, Sunway University, Subang Jaya 47500, Selangor, Malaysia
| | - Naveed Ahmed Khan
- Department of Biology, Chemistry and Environmental Sciences, College of Arts and Sciences, American University of Sharjah, Sharjah 26666, United Arab Emirates
| | - Ruqaiyyah Siddiqui
- Department of Biology, Chemistry and Environmental Sciences, College of Arts and Sciences, American University of Sharjah, Sharjah 26666, United Arab Emirates
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9
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Anwar A, Siddiqui R, Khan NA. Whole Organism Model to Study Molecular Mechanisms of Differentiation and Dedifferentiation. BIOLOGY 2020; 9:E79. [PMID: 32316619 PMCID: PMC7235994 DOI: 10.3390/biology9040079] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Revised: 04/14/2020] [Accepted: 04/15/2020] [Indexed: 12/25/2022]
Abstract
Cancer recurrence has remained a significant challenge, despite advances in therapeutic approaches. In part, this is due to our incomplete understanding of the biology of cancer stem cells and the underlying molecular mechanisms. The phenomenon of differentiation and dedifferentiation (phenotypic switching) is not only unique to stem cells but it is also observed in several other organisms, as well as evolutionary-related microbes. Here, we propose the use of a primitive eukaryotic unicellular organism, Acanthamoeba castellanii, as a model to study the molecular mechanisms of cellular differentiation and dedifferentiation.
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Affiliation(s)
- Areeba Anwar
- Department of Biological Sciences, School of Science and Technology, Sunway University, Bandar Sunway 47500, Malaysia;
| | - Ruqaiyyah Siddiqui
- Department of Biology, Chemistry and Environmental Sciences, College of Arts and Sciences, American University of Sharjah, University City 26666, UAE;
| | - Naveed Ahmed Khan
- Department of Biology, Chemistry and Environmental Sciences, College of Arts and Sciences, American University of Sharjah, University City 26666, UAE;
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10
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Koutsogiannis Z, MacLeod ET, Maciver SK. G418 induces programmed cell death in Acanthamoeba through the elevation of intracellular calcium and cytochrome c translocation. Parasitol Res 2019; 118:641-651. [PMID: 30617503 PMCID: PMC6349814 DOI: 10.1007/s00436-018-6192-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Accepted: 12/19/2018] [Indexed: 11/27/2022]
Abstract
Acanthamoeba is a widely distributed opportunistic parasite which causes a vision-threatening keratitis and a life-threatening encephalitis. The cyst stage of this amoeba is especially resistant to currently used therapeutics and so alternative agents are urgently required. Growing evidence supports the existence of a programmed cell death system (PCD) in Acanthamoeba and while some features are shared by higher eukaryote cells, others differ. It is hoped that by understanding these differences we can exploit them as targets for novel drug intervention to activate PCD pathways in the amoebae but not the invaded human tissue. Here, we use the aminoglycoside G418 to activate PCD in Acanthamoeba. This drug caused a shape change in the treated amoebae. Cells rounded up and contracted, and after 6 h fragments of cells resembling the ‘apoptotic bodies’ of vertebrate cells were observed. G418 causes an increase in intracellular calcium from a resting level of 24 nM to 60 nM after 6 h of treatment. Mitochondrial function as assayed by the ΔΨm reporting dye JC-1 and CTC a redox dye becomes inhibited during treatment and we have found that cytochrome c is released from the mitochondria. Cells stained with Hoechst showed first an alteration in chromatin structure and then a vesiculation of the nucleus with G418 treatment, although we found no obvious breakdown in genomic DNA in the early stages of PCD.
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Affiliation(s)
| | - Ewan T MacLeod
- Division of Infection and Pathway Medicine, Biomedical Sciences, Edinburgh Medical School, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, Scotland, EH8 9XD, UK
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11
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Moon EK, Choi HS, Kong HH, Quan FS. Polyhexamethylene biguanide and chloroquine induce programmed cell death in Acanthamoeba castellanii. Exp Parasitol 2018; 191:31-35. [PMID: 29885293 DOI: 10.1016/j.exppara.2018.06.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 04/24/2018] [Accepted: 06/05/2018] [Indexed: 01/02/2023]
Abstract
Several chemotherapeutic drugs have been described as amoebicidal agents acting against Acanthamoeba trophozoites and cysts. However, the underlying mechanism of action is poorly characterized. Here, we describe programmed cell death (PCD) in A. castellanii induced by polyhexamethylene biguanide (PHMB) and chloroquine. We used four types of amoebicidal agents including 0.02% PHMB, 0.02% chlorhexidine digluconate, 100 μM chloroquine, and 100 μM 2,6-dichlorobenzonitrile to kill Acanthamoeba trophozoites and cysts. Exposure to PHMB and chloroquine induced cell shrinkage and membrane blebbing in Acanthamoeba, observed microscopically. Externalization of phosphatidyl serine on the membranes of Acanthamoeba was detected by annexin V staining. Apoptotic cell death of Acanthamoeba by PHMB and chloroquine was confirmed by FACS analysis. Nuclear fragmentation of Acanthamoeba was demonstrated by DAPI staining. PHMB induced PCD in trophozoites and cysts, and chloroquine induced PCD in cysts. These findings are discussed to establish the most effective treatment for Acanthamoeba-induced keratitis.
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Affiliation(s)
- Eun-Kyung Moon
- Department of Medical Zoology, Kyung Hee University School of Medicine, Seoul, 02447, Republic of Korea
| | - Hyun-Seo Choi
- Department of Medical Zoology, Kyung Hee University School of Medicine, Seoul, 02447, Republic of Korea
| | - Hyun-Hee Kong
- Department of Parasitology, Dong-A University College of Medicine, Busan, 49201, Republic of Korea
| | - Fu-Shi Quan
- Department of Medical Zoology, Kyung Hee University School of Medicine, Seoul, 02447, Republic of Korea; Biomedical Science Institute, Kyung Hee University School of Medicine, Seoul, 02447, Republic of Korea.
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In vitro activity of 1H-phenalen-1-one derivatives against Acanthamoeba castellanii Neff and their mechanisms of cell death. Exp Parasitol 2017; 183:218-223. [PMID: 28916457 DOI: 10.1016/j.exppara.2017.09.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Revised: 08/10/2017] [Accepted: 09/11/2017] [Indexed: 12/20/2022]
Abstract
Acanthamoeba is an opportunistic pathogen which is the causal agent of a sight-threatening ulceration of the cornea known as Acanthamoeba keratitis (AK) and, more rarely, an infection of the central nervous system called "granulomatous amoebic encephalitis" (GAE). The symptoms of AK are non-specific, and so it can be misdiagnosed as a viral, bacterial, or fungal keratitis. Furthermore, current therapeutic measures against AK are arduous, and show limited efficacy against the cyst stage of Acanthamoeba. 1H-Phenalen-1-one (PH) containing compounds have been isolated from plants and fungi, where they play a crucial role in the defense mechanism of plants. Natural as well as synthetic PHs exhibit a diverse range of biological activities against fungi, protozoan parasites or human cancer cells. New synthetic PHs have been tested in this study and they show a potential activity against this protozoa.
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