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Bessenay A, Bisio H, Belmudes L, Couté Y, Bertaux L, Claverie JM, Abergel C, Jeudy S, Legendre M. Complex transcriptional regulations of a hyperparasitic quadripartite system in giant viruses infecting protists. Nat Commun 2024; 15:8608. [PMID: 39384766 PMCID: PMC11464507 DOI: 10.1038/s41467-024-52906-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2024] [Accepted: 09/25/2024] [Indexed: 10/11/2024] Open
Abstract
Hyperparasitism is a common pattern in nature that is not limited to cellular organisms. Giant viruses infecting protists can be hyperparasitized by smaller ones named virophages. In addition, both may carry episomal DNA molecules known as transpovirons in their particles. They all share transcriptional regulatory elements that dictate the expression of their genes within viral factories built by giant viruses in the host cytoplasm. This suggests the existence of interactions between their respective transcriptional networks. Here we investigated Acanthamoeba castellanii cells infected by a giant virus (megavirus chilensis), and coinfected with a virophage (zamilon vitis) and/or a transpoviron (megavirus vitis transpoviron). Infectious cycles were monitored through time-course RNA sequencing to decipher the transcriptional program of each partner and its impact on the gene expression of the others. We found highly diverse transcriptional responses. While the giant virus drastically reshaped the host cell transcriptome, the transpoviron had no effect on the gene expression of any of the players. In contrast, the virophage strongly modified the giant virus gene expression, albeit transiently, without altering the protein composition of mature viral particles. The virophage also induced the overexpression of transpoviron genes, likely through the indirect upregulation of giant virus-encoded transcription factors. Together, these analyses document the intricated transcriptionally regulated networks taking place in the infected cell.
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Affiliation(s)
- Alexandra Bessenay
- Aix-Marseille University, Centre National de la Recherche Scientifique, Information Génomique & Structurale (IGS), Unité Mixte de Recherche 7256 (Institut de Microbiologie de la Méditerranée, FR3479), IM2B, IOM, Marseille, Cedex 9, France
| | - Hugo Bisio
- Aix-Marseille University, Centre National de la Recherche Scientifique, Information Génomique & Structurale (IGS), Unité Mixte de Recherche 7256 (Institut de Microbiologie de la Méditerranée, FR3479), IM2B, IOM, Marseille, Cedex 9, France
| | - Lucid Belmudes
- Univ. Grenoble Alpes, INSERM, CEA, UA13 BGE, CNRS, CEA, FR2048, Grenoble, France
| | - Yohann Couté
- Univ. Grenoble Alpes, INSERM, CEA, UA13 BGE, CNRS, CEA, FR2048, Grenoble, France
| | - Lionel Bertaux
- Aix-Marseille University, Centre National de la Recherche Scientifique, Information Génomique & Structurale (IGS), Unité Mixte de Recherche 7256 (Institut de Microbiologie de la Méditerranée, FR3479), IM2B, IOM, Marseille, Cedex 9, France
- Aix-Marseille University, Centre National de la Recherche Scientifique, Laboratoire de Chimie Bactérienne (LCB), Unité Mixte de Recherche 7283 (Institut de Microbiologie de la Méditerranée, FR3479), IM2B, Marseille, France
| | - Jean-Michel Claverie
- Aix-Marseille University, Centre National de la Recherche Scientifique, Information Génomique & Structurale (IGS), Unité Mixte de Recherche 7256 (Institut de Microbiologie de la Méditerranée, FR3479), IM2B, IOM, Marseille, Cedex 9, France
| | - Chantal Abergel
- Aix-Marseille University, Centre National de la Recherche Scientifique, Information Génomique & Structurale (IGS), Unité Mixte de Recherche 7256 (Institut de Microbiologie de la Méditerranée, FR3479), IM2B, IOM, Marseille, Cedex 9, France
| | - Sandra Jeudy
- Aix-Marseille University, Centre National de la Recherche Scientifique, Information Génomique & Structurale (IGS), Unité Mixte de Recherche 7256 (Institut de Microbiologie de la Méditerranée, FR3479), IM2B, IOM, Marseille, Cedex 9, France.
| | - Matthieu Legendre
- Aix-Marseille University, Centre National de la Recherche Scientifique, Information Génomique & Structurale (IGS), Unité Mixte de Recherche 7256 (Institut de Microbiologie de la Méditerranée, FR3479), IM2B, IOM, Marseille, Cedex 9, France.
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Lê HG, Hwang BS, Choi JS, Jeong YT, Kang JM, Võ TC, Oh YT, Na BK. Iris setosa Pall. ex Link Extract Reveals Amoebicidal Activity against Acanthamoeba castellanii and Acanthamoeba polyphaga with Low Toxicity to Human Corneal Cells. Microorganisms 2024; 12:1658. [PMID: 39203500 PMCID: PMC11356916 DOI: 10.3390/microorganisms12081658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2024] [Revised: 08/08/2024] [Accepted: 08/09/2024] [Indexed: 09/03/2024] Open
Abstract
Acanthamoeba keratitis (AK) is a sight-threatening and difficult-to-treat ocular infection. The significant side effects of current AK treatments highlight the urgent need to develop a safe and effective AK medication. In this study, the amoebicidal activity of Iris setosa Pall. ex Link extract (ISE) against Acanthamoeba was examined and its specific amoebicidal mechanism was explored. ISE induced significant morphological changes in Acanthamoeba trophozoites and exhibited amoebicidal activity against A. castellanii and A. polyphaga. ISE was further fractionated into five subfractions by sequential extraction with n-hexane, chloroform, ethyl acetate, n-butanol, and water, and their amoebicidal activities and underlying amoebicidal mechanisms were investigated. The n-butanol subfraction of ISE (ISE-BuOH) displayed selective amoebicidal activity against the Acanthamoeba species with minimal cytotoxicity in human corneal cells (HCE-2). ISE-BuOH triggered apoptosis-like programmed cell death (PCD) in amoebae, characterized by DNA fragmentation, increased ROS production, and caspase-3 activity elevation. ISE-BuOH also demonstrated a partial cysticidal effect against the amoeba species. ISE-BuOH could be a promising candidate in the development of therapeutic drugs for AK.
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Affiliation(s)
- Hương Giang Lê
- Department of Parasitology and Tropical Medicine, and Institute of Health Science, Gyeongsang National University College of Medicine, Jinju 52727, Republic of Korea; (H.G.L.); (J.-M.K.); (T.C.V.)
- Department of Convergence Medical Science, Gyeongsang National University, Jinju 52727, Republic of Korea
| | - Buyng Su Hwang
- Nakdonggang National Institute of Biological Resources, Sangju 37242, Republic of Korea; (B.S.H.); (J.-S.C.); (Y.T.J.)
| | - Ji-Su Choi
- Nakdonggang National Institute of Biological Resources, Sangju 37242, Republic of Korea; (B.S.H.); (J.-S.C.); (Y.T.J.)
| | - Yong Tae Jeong
- Nakdonggang National Institute of Biological Resources, Sangju 37242, Republic of Korea; (B.S.H.); (J.-S.C.); (Y.T.J.)
| | - Jung-Mi Kang
- Department of Parasitology and Tropical Medicine, and Institute of Health Science, Gyeongsang National University College of Medicine, Jinju 52727, Republic of Korea; (H.G.L.); (J.-M.K.); (T.C.V.)
- Department of Convergence Medical Science, Gyeongsang National University, Jinju 52727, Republic of Korea
| | - Tuấn Cường Võ
- Department of Parasitology and Tropical Medicine, and Institute of Health Science, Gyeongsang National University College of Medicine, Jinju 52727, Republic of Korea; (H.G.L.); (J.-M.K.); (T.C.V.)
- Department of Convergence Medical Science, Gyeongsang National University, Jinju 52727, Republic of Korea
| | - Young Taek Oh
- Nakdonggang National Institute of Biological Resources, Sangju 37242, Republic of Korea; (B.S.H.); (J.-S.C.); (Y.T.J.)
| | - Byoung-Kuk Na
- Department of Parasitology and Tropical Medicine, and Institute of Health Science, Gyeongsang National University College of Medicine, Jinju 52727, Republic of Korea; (H.G.L.); (J.-M.K.); (T.C.V.)
- Department of Convergence Medical Science, Gyeongsang National University, Jinju 52727, Republic of Korea
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3
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Abdel-Hakeem SS, Hassan FAM, Hifney AF, Salem SH. Combating the causative agent of amoebic keratitis, Acanthamoeba castellanii, using Padina pavonica alcoholic extract: toxicokinetic and molecular docking approaches. Sci Rep 2024; 14:13610. [PMID: 38871751 DOI: 10.1038/s41598-024-63691-8] [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: 03/24/2024] [Accepted: 05/31/2024] [Indexed: 06/15/2024] Open
Abstract
Natural products play a significant role in providing the current demand as antiparasitic agents, which offer an attractive approach for the discovery of novel drugs. The present study aimed to evaluate in vitro the potential impact of seaweed Padina pavonica (P. pavonica) extract in combating Acanthamoeba castellanii (A. castellanii). The phytochemical constituents of the extract were characterized by Gas chromatography-mass spectrometry. Six concentrations of the algal extract were used to evaluate its antiprotozoal activity at various incubation periods. Our results showed that the extract has significant inhibition against trophozoites and cysts viability, with complete inhibition at the high concentrations. The IC50 of P. pavonica extract was 4.56 and 4.89 µg/mL for trophozoites and cysts, respectively, at 24 h. Morphological alterations of A. castellanii trophozoites/cysts treated with the extract were assessed using inverted and scanning electron microscopes and showed severe damage features upon treatment with the extract at different concentrations. Molecular Docking of extracted compounds against Acanthamoeba cytochrome P450 monooxygenase (AcCYP51) was performed using Autodock vina1.5.6. A pharmacokinetic study using SwissADME was also conducted to investigate the potentiality of the identified bioactive compounds from Padina extract to be orally active drug candidates. In conclusion, this study highlights the in vitro amoebicidal activity of P. pavonica extract against A. castellanii adults and cysts and suggests potential AcCYP51 inhibition.
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Affiliation(s)
- Sara S Abdel-Hakeem
- Parasitology Laboratory, Zoology and Entomology Department, Faculty of Science, Assiut University, Assiut, 71526, Egypt
| | - Faten A M Hassan
- Microbiology Department, Faculty of Science, Taiz University, Taiz, Yemen
| | - Awatief F Hifney
- Botany and Microbiology Department, Faculty of Science, Assiut University, Assiut, 71526, Egypt
| | - Shimaa H Salem
- Botany and Microbiology Department, Faculty of Science, Assiut University, Assiut, 71526, Egypt.
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Simau FA, Ahmed U, Khan KM, Khan NA, Siddiqui R, Alharbi AM, Alfahemi H, Anwar A. Lactase can target cellular differentiation of Acanthamoeba castellanii belonging to the T4 genotype. Parasitol Res 2024; 123:117. [PMID: 38294565 DOI: 10.1007/s00436-024-08131-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Accepted: 01/17/2024] [Indexed: 02/01/2024]
Abstract
The free living Acanthamoeba spp. are ubiquitous amoebae associated with potentially blinding disease known as Acanthamoeba keratitis (AK) and a fatal central nervous system infection granulomatous amoebic encephalitis (GAE). With the inherent ability of cellular differentiation, it can phenotypically transform to a dormant cyst form from an active trophozoite form. Acanthamoeba cysts are highly resistant to therapeutic agents as well as contact lens cleaning solutions. One way to tackle drug resistance against Acanthamoeba is by inhibiting the formation of cysts from trophozoites. The biochemical analysis showed that the major component of Acanthamoeba cyst wall is composed of carbohydrate moieties such as galactose and glucose. The disaccharide of galactose and glucose is lactose. In this study, we analyzed the potential of lactase enzyme to target carbohydrate moieties of cyst walls. Amoebicidal assessment showed that lactase was ineffective against trophozoite of A. castellanii but enhanced amoebicidal effects of chlorhexidine. The lactase enzyme did not show any toxicity against normal human keratinocyte cells (HaCaT) at the tested range. Hence, lactase can be used for further assessment for development of potential therapeutic agents in the management of Acanthamoeba infection as well as formulation of effective contact lens disinfectants.
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Affiliation(s)
- Fathimath Afaaf Simau
- Department of Biological Sciences, School of Medical and Life Sciences, Sunway University, Subang Jaya, 47500, Selangor, Malaysia
| | - Usman Ahmed
- Department of Biological Sciences, School of Medical and Life Sciences, Sunway University, Subang Jaya, 47500, Selangor, Malaysia
| | - Khalid Mohammed Khan
- International Center for Chemical and Biological Sciences, H. E. J. Research Institute of Chemistry, 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, Istanbul, 34010, Turkey.
| | - Ruqaiyyah Siddiqui
- Microbiota Research Center, Istinye University, Istanbul, 34010, Turkey
- Institute of Biological Chemistry, Biophysics and Bioengineering, Heriot-Watt University, Edinburgh, EH14 4AS, UK
| | - Ahmad M Alharbi
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Taif University, 21944, Taif, Saudi Arabia
| | - Hasan Alfahemi
- Department of Medical Microbiology, Faculty of Medicine, Al-Baha University, 65799, Al-Baha, 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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Scheckhuber CQ, Damián Ferrara R, Gómez-Montalvo J, Maciver SK, de Obeso Fernández Del Valle A. Oxidase enzyme genes are differentially expressed during Acanthamoeba castellanii encystment. Parasitol Res 2024; 123:116. [PMID: 38289423 DOI: 10.1007/s00436-024-08138-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Accepted: 01/22/2024] [Indexed: 02/01/2024]
Abstract
Acanthamoeba castellanii, a ubiquitous protozoan, is responsible for significant diseases such as Acanthamoeba keratitis and granulomatous amoebic encephalitis. A crucial survival strategy of A. castellanii involves the formation of highly resistant cysts during adverse conditions. This study delves into the cellular processes underpinning encystment, focusing on gene expression changes related to reactive oxygen species (ROS) balance, with a particular emphasis on mitochondrial processes. Our findings reveal a dynamic response within the mitochondria during encystment, with the downregulation of key enzymes involved in oxidative phosphorylation (COX, AOX, and NADHalt) during the initial 48 h, followed by their overexpression at 72 h. This orchestrated response likely creates a pro-oxidative environment, facilitating encystment. Analysis of other ROS processing enzymes across the cell reveals differential expression patterns. Notably, antioxidant enzymes, such as catalases, glutaredoxins, glutathione S-transferases, peroxiredoxins, and thioredoxins, mirror the mitochondrial trend of downregulation followed by upregulation. Additionally, glycolysis and gluconeogenesis are downregulated during the early stages in order to potentially balance the metabolic requirement of the cyst. Our study underscores the importance of ROS regulation in Acanthamoeba encystment. Understanding these mechanisms offers insights into infection control and identifies potential therapeutic targets. This work contributes to unraveling the complex biology of A. castellanii and may aid in combatting Acanthamoeba-related infections. Further research into ROS and oxidase enzymes is warranted, given the organism's remarkable respiratory versatility.
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Affiliation(s)
- Christian Q Scheckhuber
- Tecnologico de Monterrey, Escuela de Ingeniería y Ciencias, Ave. Eugenio Garza Sada 2501, 64849, Monterrey, N.L, Mexico
| | - Rebeca Damián Ferrara
- Tecnologico de Monterrey, Escuela de Ingeniería y Ciencias, Ave. Eugenio Garza Sada 2501, 64849, Monterrey, N.L, Mexico
| | - Jesús Gómez-Montalvo
- Tecnologico de Monterrey, Escuela de Ingeniería y Ciencias, Ave. Eugenio Garza Sada 2501, 64849, Monterrey, N.L, Mexico
| | - Sutherland K Maciver
- Centre for Discovery Brain Sciences, Edinburgh Medical School, Biomedical Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, Scotland, UK
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Milanes JE, Kwain S, Drawdy A, Dodson L, Monaghan MT, Rice CA, Dominy BN, Whitehead DC, Morris JC. Glucose metabolism in the pathogenic free-living amoebae: Tempting targets for treatment development. Chem Biol Drug Des 2024; 103:e14377. [PMID: 37864277 PMCID: PMC10843269 DOI: 10.1111/cbdd.14377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 09/18/2023] [Accepted: 10/04/2023] [Indexed: 10/22/2023]
Abstract
Pathogenic free-living amoebae (pFLA) are single-celled eukaryotes responsible for causing intractable infections with high morbidity and mortality in humans and animals. Current therapeutic approaches include cocktails of antibiotic, antifungal, and antimicrobial compounds. Unfortunately, the efficacy of these can be limited, driving the need for the discovery of new treatments. Pan anti-amebic agents would be ideal; however, identifying these agents has been a challenge, likely due to the limited evolutionary relatedness of the different pFLA. Here, we discuss the potential of targeting amoebae glucose metabolic pathways as the differences between pFLA and humans suggest specific inhibitors could be developed as leads for new therapeutics.
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Affiliation(s)
- Jillian E. Milanes
- Eukaryotic Pathogens Innovation Center, Department of Genetics and Biochemistry, Clemson University, Clemson, SC 29634
| | - Samuel Kwain
- Eukaryotic Pathogens Innovation Center, Department of Chemistry, Clemson University, Clemson SC 29634
| | - Allyson Drawdy
- Eukaryotic Pathogens Innovation Center, Department of Genetics and Biochemistry, Clemson University, Clemson, SC 29634
| | - Laura Dodson
- Eukaryotic Pathogens Innovation Center, Department of Genetics and Biochemistry, Clemson University, Clemson, SC 29634
| | - Matthew T. Monaghan
- Eukaryotic Pathogens Innovation Center, Department of Genetics and Biochemistry, Clemson University, Clemson, SC 29634
| | - Christopher A. Rice
- Department of Comparative Pathobiology, College of Veterinary Medicine, Purdue University, West Lafayette, IN 47907
- Purdue Institute for Drug Discovery (PIDD), Purdue University, West Lafayette, IN 47907
- Purdue Institute of Inflammation, Immunology and Infectious Disease (PI4D), Purdue University, West Lafayette, IN 47907
| | - Brian N. Dominy
- Department of Chemistry, Clemson University, Clemson SC 29634
| | - Daniel C. Whitehead
- Eukaryotic Pathogens Innovation Center, Department of Chemistry, Clemson University, Clemson SC 29634
| | - James C. Morris
- Eukaryotic Pathogens Innovation Center, Department of Genetics and Biochemistry, Clemson University, Clemson, SC 29634
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Ahmed U, Sivasothy Y, Khan KM, Khan NA, Wahab SMA, Awang K, Othman MA, Anwar A. Malabaricones from the fruit of Myristica cinnamomea King as potential agents against Acanthamoeba castellanii. Acta Trop 2023; 248:107033. [PMID: 37783284 DOI: 10.1016/j.actatropica.2023.107033] [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: 07/20/2023] [Revised: 09/13/2023] [Accepted: 09/29/2023] [Indexed: 10/04/2023]
Abstract
Acanthamoeba castellanii is an opportunistic free-living amoeba (FLA) pathogen which can cause fatal central nervous system (CNS) infection, granulomatous amoebic encephalitis (GAE) and potentially blinding ocular infection, Acanthamoeba keratitis (AK). Acanthamoeba species remain a challenging protist to treat due to the unavailability of safe and effective therapeutic drugs and their ability to protect themselves in the cyst stage. Natural products and their secondary metabolites play a pivotal role in drug discovery against various pathogenic microorganisms. In the present study, the ethyl acetate extract of Myristica cinnamomea King fruit was evaluated against A. castellanii (ATCC 50492), showing an IC50 of 45.102 ± 4.62 µg/mL. Previously, the bio-guided fractionation of the extract resulted in the identification of three active compounds, namely Malabaricones (A-C). The isolated and thoroughly characterized acylphenols were evaluated for their anti-amoebic activity against A. castellanii for the first time. Among tested compounds, Malabaricone B (IC50 of 101.31 ± 17.41 µM) and Malabaricone C (IC50 of 49.95 ± 6.33 µM) showed potent anti-amoebic activity against A. castellanii trophozoites and reduced their viability up-to 75 and 80 %, respectively. Moreover, both extract and Malabaricones also significantly (p < 0.05) inhibit the encystation and excystation of A. castellanii, while showed minimal toxicity against human keratinocyte cells (HaCaT cells) at lower tested concentrations. Following that, the explanation of the possible mechanism of action of purified compounds were assessed by detection of the state of chromatin. Hoechst/PI 33342 double staining showed that necrotic cell death occurred in A. castellanii trophozoites after 8 h treatment of Malabaricones (A-C). These findings demonstrate that Malabaricones B and C could serve as promising therapeutic options against A. castellanii infections.
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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
| | - Yasodha Sivasothy
- School of Pharmacy, Monash University Malaysia, Bandar Sunway, 47500, Selangor, Malaysia
| | - Khalid Mohammed Khan
- H. E. J. Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi, 75270, Pakistan
| | - Naveed Ahmed Khan
- Microbiota Research Center, Istinye University, Istanbul, 34010, Turkey
| | - Siti Mariam Abdul Wahab
- Faculty of Pharmacy and Health Sciences, Royal College of Medicine Perak, Universiti Kuala Lumpur, Ipoh, 30450, Malaysia
| | - Khalijah Awang
- Department of Chemistry, Faculty of Science, Universiti Malaya, 50603, Kuala Lumpur, Malaysia; Centre for Natural Products and Drug Discovery (CENAR), Universiti Malaya, 50603, Kuala Lumpur, Malaysia
| | - Muhamad Aqmal Othman
- Department of Chemistry, Faculty of Science, Universiti Malaya, 50603, Kuala Lumpur, Malaysia; Centre for Natural Products and Drug Discovery (CENAR), Universiti Malaya, 50603, Kuala Lumpur, Malaysia.
| | - Ayaz Anwar
- Department of Biological Sciences, School of Medical and Life Sciences, Sunway University, Subang Jaya, 47500, Selangor, Malaysia.
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Carvalho-Kelly LF, Freitas-Mesquita AL, Ferreira Pralon C, de Souza-Maciel E, Meyer-Fernandes JR. Identification and characterization of an ectophosphatase activity involved in Acanthamoeba castellanii adhesion to host cells. Eur J Protistol 2023; 91:126026. [PMID: 37871554 DOI: 10.1016/j.ejop.2023.126026] [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: 08/28/2023] [Revised: 10/06/2023] [Accepted: 10/11/2023] [Indexed: 10/25/2023]
Abstract
Acanthamoeba castellanii is a free-living amoeba and an opportunistic pathogen for humans that can cause encephalitis and, more commonly, Acanthamoeba keratitis. During its life cycle, A. castellanii may present as proliferative and infective trophozoites or resistant cysts. The adhesion of trophozoites to host cells is a key first step in the pathogenesis of infection. A major virulence protein of Acanthamoeba is a mannose-binding protein (MBP) that mediates the adhesion of amoebae to cell surfaces. Ectophosphatases are ecto-enzymes that can dephosphorylate extracellular substrates and have already been described in several microorganisms. Regarding their physiological roles, there is consistent evidence that ectophosphatase activities play an important role in parasite-host interactions. In the present work, we identified and biochemically characterized the ectophosphatase activity of A. castellanii. The ectophosphatase activity is acidic, stimulated by magnesium, cobalt and nickel, and presents the following apparent kinetic parameters: Km = 2.12 ± 0.54 mM p-NPP and Vmax = 26.12 ± 2.53 nmol p-NP × h-1 × 10-6 cells. We observed that sodium orthovanadate, ammonium molybdate, sodium fluoride, and inorganic phosphate are able to inhibit ectophosphatase activity. Comparing the two stages of the A. castellanii lifecycle, ectophosphatase activity is significantly higher in trophozoites than in cysts. The ectophosphatase activity is stimulated by mannose residues and is significantly increased when trophozoites interact with LLC-MK2 cells. The inhibition of ectophosphatase by pretreatment with sodium orthovanadate also inhibits the adhesion of trophozoites to epithelial cells. These results allow us to conclude that the ectophosphatase activity of A. castellanii is somehow important for the adhesion of trophozoites to their host cells. According to our data, we believe that the activation of MBP by mannose residues triggers the stimulation of ectophosphatase activity to facilitate the adhesion process.
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Affiliation(s)
| | | | - Clara Ferreira Pralon
- Instituto de Bioquímica Médica Leopoldo de Meis (IBqM), UFRJ, Rio de Janeiro, RJ, Brazil
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Ozpinar N, Karaman U, Ozpinar H, Dag S. Do antidiabetic drugs prevent the transformation of Acanthamoeba trophozoite into cyst form? Pathog Glob Health 2023; 117:674-680. [PMID: 36436006 PMCID: PMC10498792 DOI: 10.1080/20477724.2022.2151859] [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: 11/28/2022] Open
Abstract
This study examines the effects of three different drugs with metformin, acarbose and pioglitazone active ingredients used for antidiabetic purposes on Acanthamoeba cysts and trophozoites. Cultures of A. castellanii trophozoites and cysts were prepared to test the anti-amoebic activity of metformin, acarbose and pioglitazone. Cultures were then prepared for A. castellanii cyst and trophozoite forms and parasites were exposed to different concentrations (0.750 mg/mL, 0.375 mg/mL, 0.186 mg/mL and 0.093 mg/mL) of metformin, acarbose and pioglitazone. As a result of the study, the reproductive potential suppressive effects and conversion from trophozoite form to cyst form of all three substances on A. castellanii trophozoites and cysts were determined. Parasites were counted at 12, 24 and 48 hours in the cell counter after staining with trypan blue. In comparison of the effects of metformin, acarbose and pioglitazone used in the study on A. castellanii trophozoites and cysts, it was observed that all three substances were statistically effective against cysts and trophozoites at a concentration of 0.750 mg/mL. Furthermore, it was determined that all concentrations of the three active substances included in the study significantly decreased the rate of cyst formation even at the end of the 7th day. In this context, it was determined that all three substances have amebicidal effects, and they significantly inhibit the transformation of A. castellanii trophozoites to cyst form. It is thought that these active substances, which are currently used as anti-diabetic, can be used in combination with other drugs in A. castellanii infections based on our study findings.
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Affiliation(s)
- Necati Ozpinar
- Department of Emergency Aid and Disaster Management, Faculty of Health Sciences, Mustafa Kemal University, Antakya, Turkey
| | - Ulku Karaman
- Department of Parasitology, Faculty of Medicine, Ordu University, Ordu, Turkey
| | - Hulya Ozpinar
- Department of Pharmaceutical Botany, Faculty of Pharmacy, Sivas Cumhuriyet University, Sivas, Turkey
| | - Seker Dag
- Department of Biology, Faculty of Science, Sivas Cumhuriyet University, Sivas, Turkey
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Carvalho-Kelly LF, Freitas-Mesquita AL, Nascimento MTC, Dick CF, de Souza-Maciel E, Rochael NC, Saraiva EM, Meyer-Fernandes JR. Acanthamoeba castellanii trophozoites escape killing by neutrophil extracellular traps using their 3'-nucleotidase/nuclease activity. Eur J Protistol 2023; 91:126032. [PMID: 37948889 DOI: 10.1016/j.ejop.2023.126032] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 10/27/2023] [Accepted: 10/30/2023] [Indexed: 11/12/2023]
Abstract
Acanthamoeba castellanii is a free-living amoeba that acts as an opportunistic pathogen for humans and is the pathogenic agent of Acanthamoeba keratitis (AK). A. castellanii may present as proliferative and infective trophozoites or as resistant cysts during their life cycle. The immune response against AK is still poorly explored; however, it is well established that macrophages and neutrophils play essential roles in controlling corneal infection during the disease outcome. The release of NETs is one of the innate immune strategies to prevent parasite infection, especially when neutrophils interact with microorganisms that are too large to be phagocytosed, which is the case for amoeba species. The present work demonstrated that A. castellanii trophozoites can trigger NET formation upon in vitro interaction with neutrophils. Using DNase as a control, we observed increased parasite survival after coinciding with neutrophils, which may be correlated with NET degradation. Indeed, A. castellanii trophozoites degrade the NET DNA scaffold. Molecular analysis confirmed the occurrence of a 3'-nucleotidase/nuclease (3'-NT/NU) in the A. castellanii genome. We also demonstrated that trophozoites exhibit significantly higher 3'-NT/NU activity than cysts, which cannot trigger NET release. Considering that previous studies indicated the pathological role of 3'-NT-/NU in parasite infection, we suggest that this enzyme may act as the mechanism of escape of A. castellanii trophozoites from NETs.
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Affiliation(s)
| | | | - Michelle T C Nascimento
- Instituto de Bioquímica Médica Leopoldo de Meis (IBqM), UFRJ, Rio de Janeiro, RJ, Brazil; Instituto de Microbiologia Paulo de Góes (IMPG), UFRJ, Rio de Janeiro, RJ, Brazil
| | - Claudia F Dick
- Instituto de Biofísica Carlos Chagas Filho (IBCCF), UFRJ, Rio de Janeiro, RJ, Brazil
| | | | - Natalia C Rochael
- Instituto de Microbiologia Paulo de Góes (IMPG), UFRJ, Rio de Janeiro, RJ, Brazil
| | - Elvira M Saraiva
- Instituto de Microbiologia Paulo de Góes (IMPG), UFRJ, Rio de Janeiro, RJ, Brazil
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11
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Siddiqui R, Makhlouf Z, Akbar N, Khamis M, Ibrahim T, Khan AS, Khan NA. Antiamoebic properties of Methyltrioctylammonium chloride based deep eutectic solvents. Cont Lens Anterior Eye 2023; 46:101758. [PMID: 36243521 DOI: 10.1016/j.clae.2022.101758] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2022] [Revised: 09/06/2022] [Accepted: 09/09/2022] [Indexed: 11/25/2022]
Abstract
PURPOSE This aim of this study was to assess anti-parasitic properties of deep eutectic solvents against eye pathogen, Acanthamoeba, often associated with the use of contact lens. METHODS Assays were performed to investigate the effects of various Methyltrioctylammonium chloride-based deep eutectic solvents on Acanthamoeba castellanii, comprising amoebicidal assays, encystment assays, excystment assays, cytotoxicity assays by measuring lactate dehydrogenase release from human cells, and cytopathogenicity assays to determine parasite-mediated host cell death. RESULTS In a 2 h incubation period, DES-B, DES-C, DES-D, and DES-E exhibited up to 85 % amoebicidal activity at micromolar doses, which was enhanced further following 24 h incubation. When tested in encystment assays, selected deep eutectic solvents abolished cyst formation and were able to block excystment of A. castellanii. All solvents exhibited minimal human cell cytotoxicity except DES-D. Finally, all tested deep eutectic solvents inhibited amoeba-mediated cytopathogenicity, except DES-B. CONCLUSIONS Deep eutectic solvents show potent antiamoebic effects. These findings are promising and could lead to the development of novel contact lens disinfectants, as well as opening several avenues to explore the molecular mechanisms, various doses and incubation periods, and use of different bases against Acanthamoeba castellanii.
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Affiliation(s)
- Ruqaiyyah Siddiqui
- College of Arts and Sciences, American University of Sharjah, University City, Sharjah 26666, United Arab Emirates; Istinye Faculty of Medicine, Istinye University, Istanbul, Turkey
| | - Zinb Makhlouf
- College of Arts and Sciences, American University of Sharjah, University City, Sharjah 26666, United Arab Emirates
| | - Noor Akbar
- College of Arts and Sciences, American University of Sharjah, University City, Sharjah 26666, United Arab Emirates
| | - Mustafa Khamis
- College of Arts and Sciences, American University of Sharjah, University City, Sharjah 26666, United Arab Emirates
| | - Taleb Ibrahim
- Department of Chemical Engineering, College of Engineering, American University of Sharjah, P.O. Box 26666, Sharjah, United Arab Emirates
| | - Amir Sada Khan
- Department of Chemical Engineering, College of Engineering, American University of Sharjah, P.O. Box 26666, Sharjah, United Arab Emirates; Department of Chemistry, University of Science & Technology, Banuu 28100, Khyber Pakhtunkhwa, C
| | - Naveed Ahmed Khan
- Department of Clinical Sciences, College of Medicine, University of Sharjah, University, City, Sharjah 27272, United Arab Emirates; Istinye Faculty of Medicine, Istinye University, Istanbul, Turkey..
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12
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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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Lacerda-Abreu MA, Dick CF, Meyer-Fernandes JR. The Role of Inorganic Phosphate Transporters in Highly Proliferative Cells: From Protozoan Parasites to Cancer Cells. MEMBRANES 2022; 13:42. [PMID: 36676849 PMCID: PMC9860751 DOI: 10.3390/membranes13010042] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 12/01/2022] [Accepted: 12/26/2022] [Indexed: 06/17/2023]
Abstract
In addition to their standard inorganic phosphate (Pi) nutritional function, Pi transporters have additional roles in several cells, including Pi sensing (the so-called transceptor) and a crucial role in Pi metabolism, where they control several phenotypes, such as virulence in pathogens and tumour aggressiveness in cancer cells. Thus, intracellular Pi concentration should be tightly regulated by the fine control of intake and storage in organelles. Pi transporters are classified into two groups: the Pi transporter (PiT) family, also known as the Pi:Na+ symporter family; and the Pi:H+ symporter (PHS) family. Highly proliferative cells, such as protozoan parasites and cancer cells, rely on aerobic glycolysis to support the rapid generation of biomass, which is equated with the well-known Warburg effect in cancer cells. In protozoan parasite cells, Pi transporters are strongly associated with cell proliferation, possibly through their action as intracellular Pi suppliers for glyceraldehyde-3-phosphate dehydrogenase (GAPDH) activity. Similarly, the growth rate hypothesis (GRH) proposes that the high Pi demands of tumours when achieving accelerated proliferation are mainly due to increased allocation to P-rich nucleic acids. The purpose of this review was to highlight recent advances in understanding the role of Pi transporters in unicellular eukaryotes and tumorigenic cells, correlating these roles with metabolism in these cells.
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Affiliation(s)
- Marco Antonio Lacerda-Abreu
- Leopoldo de Meis Institute of Medical Biochemistry, Federal University of Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
| | - Claudia Fernanda Dick
- National Center of Structural Biology and Bioimaging (CENABIO), Federal University of Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
| | - José Roberto Meyer-Fernandes
- Leopoldo de Meis Institute of Medical Biochemistry, Federal University of Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
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Campolo A, Pifer R, Walters R, Thomas M, Miller E, Harris V, King J, Rice CA, Shannon P, Patterson B, Crary M. Acanthamoeba spp. aggregate and encyst on contact lens material increasing resistance to disinfection. Front Microbiol 2022; 13:1089092. [PMID: 36601401 PMCID: PMC9806144 DOI: 10.3389/fmicb.2022.1089092] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Accepted: 11/28/2022] [Indexed: 12/23/2022] Open
Abstract
Introduction Acanthamoeba keratitis is often caused when Acanthamoeba contaminate contact lenses and infect the cornea. Acanthamoeba is pervasive in the environment as a motile, foraging trophozoite or biocide-resistant and persistent cyst. As contact lens contamination is a potential first step in infection, we studied Acanthamoeba's behavior and interactions on different contact lens materials. We hypothesized that contact lenses may induce aggregation, which is a precursor to encystment, and that aggregated encystment would be more difficult to disinfect than motile trophozoites. Methods Six clinically and/or scientifically relevant strains of Acanthamoeba (ATCC 30010, ATCC 30461, ATCC 50370, ATCC 50702, ATCC 50703, and ATCC PRA-115) were investigated on seven different common silicone hydrogel contact lenses, and a no-lens control, for aggregation and encystment for 72 h. Cell count and size were used to determine aggregation, and fluorescent staining was used to understand encystment. RNA seq was performed to describe the genome of Acanthamoeba which was individually motile or aggregated on different lens materials. Disinfection efficacy using three common multi-purpose solutions was calculated to describe the potential disinfection resistance of trophozoites, individual cysts, or spheroids. Results Acanthamoeba trophozoites of all strains examined demonstrated significantly more aggregation on specific contact lens materials than others, or the no-lens control. Fluorescent staining demonstrated encystment in as little as 4 hours on contact lens materials, which is substantially faster than previously reported in natural or laboratory settings. Gene expression profiles corroborated encystment, with significantly differentially expressed pathways involving actin arrangement and membrane complexes. High disinfection resistance of cysts and spheroids with multi-purpose solutions was observed. Discussion Aggregation/encystment is a protective mechanism which may enable Acanthamoeba to be more disinfection resistant than individual trophozoites. This study demonstrates that some contact lens materials promote Acanthamoeba aggregation and encystment, and Acanthamoeba spheroids obstruct multi-purpose solutions from disinfecting Acanthamoeba.
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Affiliation(s)
| | - Reed Pifer
- Alcon Research, LLC, Fort Worth, TX, United States
| | | | - Megan Thomas
- Alcon Research, LLC, Fort Worth, TX, United States
| | - Elise Miller
- Alcon Research, LLC, Fort Worth, TX, United States
| | | | - Jamie King
- Alcon Research, LLC, Fort Worth, TX, United States
| | - Christopher A. Rice
- Department of Comparative Pathobiology, College of Veterinary Medicine, Purdue University, West Lafayette, IN, United States,Purdue Institute for Drug Discovery (PIDD), Purdue University, West Lafayette, IN, United States,Purdue Institute of Inflammation, Immunology and Infectious Disease (PI4D), Purdue University, West Lafayette, IN, United States
| | - Paul Shannon
- Alcon Research, LLC, Fort Worth, TX, United States
| | | | - Monica Crary
- Alcon Research, LLC, Fort Worth, TX, United States,*Correspondence: Monica Crary,
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15
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Nikam PB, Salunkhe JD, Marathe KR, Alghuthaymi MA, Abd-Elsalam KA, Patil SV. Rhizobium pusense-Mediated Selenium Nanoparticles-Antibiotics Combinations against Acanthamoeba sp. Microorganisms 2022; 10:microorganisms10122502. [PMID: 36557755 PMCID: PMC9785558 DOI: 10.3390/microorganisms10122502] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 12/05/2022] [Accepted: 12/12/2022] [Indexed: 12/23/2022] Open
Abstract
Severe ocular infections by Acanthamoeba sp. lead to keratitis, resulting in irreversible vision loss in immune-compromised individuals. When a protozoal infection spreads to neural tissues, it causes granulomatous encephalitis, which can be fatal. Treatment often takes longer due to the transition of amoeba from trophozoites to cyst stages, cyst being the dormant form of Acanthamoeba. A prolonged use of therapeutic agents, such as ciprofloxacin (Cipro), results in severe side effects; thus, it is critical to improve the therapeutic efficacy of these widely used antibiotics, possibly by limiting the drug-sensitive protozoal-phase transition to cyst formation. Owing to the biomedical potential of selenium nanoparticles (SeNPs), we evaluated the synergistic effects of ciprofloxacin and Rhizobium pusense-biogenic SeNPs combination. SeNPs synthesized using Rhizobium pusense isolated from root nodules were characterized using UV-Visible spectrophotometer, FT-IR, SEM with EDX, particle size analysis, and Zeta potential. The combination was observed to reduce the sub-lethal dose of Cipro, which may help reduce its side effects. The selenium and ciprofloxacin (SeNPs-Cipro) combination reduced the LC50 by 33.43%. The anti-protozoal efficacy of SeNPs-Cipro was found to transduce through decreased protozoal-cyst formations and the inhibition of the galactosidase and protease enzymes of trophozoites. Furthermore, high leakage of sugar, proteins, and amino acids during the SeNPs-Cipro treatment was one primary reason for killing the trophozoites. These experimental results may be helpful in the further pre-clinical evaluation of SeNPs-Cipro to combat protozoal infections. Future studies for combinations of SeNPs with other antibiotics need to be conducted to know the potential of SeNPs against antibiotic resistance in Acanthamoeba.
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Affiliation(s)
- Pradnya B. Nikam
- Department of Biochemistry, School of Life Sciences, Kavayitri Bahinabai Chaudhari North Maharashtra University, Jalgaon 425001, India
| | - Jitendra D. Salunkhe
- Department of Biochemistry, School of Life Sciences, Kavayitri Bahinabai Chaudhari North Maharashtra University, Jalgaon 425001, India
| | - Kiran R. Marathe
- Department of Biochemistry, School of Life Sciences, Kavayitri Bahinabai Chaudhari North Maharashtra University, Jalgaon 425001, India
| | - Mousa A. Alghuthaymi
- Biology Department, Science and Humanities College, Shaqra University, Alquwayiyah 11971, Saudi Arabia
| | - Kamel A. Abd-Elsalam
- Plant Pathology Research Institute, Agricultural Research Center, Giza 12619, Egypt
- Correspondence: (K.A.A.-E.); or (S.V.P.); Tel.: +91-0257-2257421–25 (S.V.P.)
| | - Satish V. Patil
- Department of Biochemistry, School of Life Sciences, Kavayitri Bahinabai Chaudhari North Maharashtra University, Jalgaon 425001, India
- Correspondence: (K.A.A.-E.); or (S.V.P.); Tel.: +91-0257-2257421–25 (S.V.P.)
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16
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Salazar-Ardiles C, Asserella-Rebollo L, Andrade DC. Free-Living Amoebas in Extreme Environments: The True Survival in our Planet. BIOMED RESEARCH INTERNATIONAL 2022; 2022:2359883. [PMID: 36303587 PMCID: PMC9596261 DOI: 10.1155/2022/2359883] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Accepted: 09/08/2022] [Indexed: 12/03/2022]
Abstract
Free-living amoebas (FLAs) are microorganisms, unicellular protozoa widely distributed in nature and present in different environments, such as water or soil; they are maintained in ecosystems and play a fundamental role in the biological control of bacteria, other protozoa, and mushrooms. In particular circumstances, some can reach humans or animals, promoting several health complications. Notably, FLAs are characterized by a robust capacity to survive in extreme environments. However, currently, there is no updated information on the existence and distribution of this protozoan in inhospitable places. Undoubtedly, the cellular physiology of these protozoan microorganisms is very particular. They can resist and live in extreme environments due to their encysting capacity and tolerance to different osmolarities, temperatures, and other environmental factors, which give them excellent adaptative resistance. In this review, we summarized the most relevant evidence related to FLAs and the possible mechanism, which could explain their adaptative capacity to several extreme environments.
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Affiliation(s)
- Camila Salazar-Ardiles
- Research Center in High Altitude Medicine and Physiology, Biomedical Department, Faculty of Health Science, University of Antofagasta, Antofagasta, Chile
| | | | - David C. Andrade
- Research Center in High Altitude Medicine and Physiology, Biomedical Department, Faculty of Health Science, University of Antofagasta, Antofagasta, Chile
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Rased NM, Johari SATT, Zakeri HA, Ma NL, Razali SA, Hashim F. Combinatorial treatment with β-glucanase enzyme and chlorhexidine induces cysticidal effects in Acanthamoeba cyst. Parasitol Res 2022; 121:3105-3119. [DOI: 10.1007/s00436-022-07650-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2021] [Accepted: 08/29/2022] [Indexed: 11/24/2022]
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Fechtali-Moute Z, Loiseau PM, Pomel S. Stimulation of Acanthamoeba castellanii excystment by enzyme treatment and consequences on trophozoite growth. Front Cell Dev Biol 2022; 10:982897. [PMID: 36172275 PMCID: PMC9511172 DOI: 10.3389/fcell.2022.982897] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 08/17/2022] [Indexed: 11/13/2022] Open
Abstract
Acanthamoeba castellanii is a widespread Free-Living Amoeba (FLA) that can cause severe ocular or cerebral infections in immunocompetent and immunocompromised patients, respectively, besides its capacity to transport diverse pathogens. During their life cycle, FLA can alternate between a vegetative form, called a trophozoite, and a latent and resistant form, called a cyst. This resistant form is characterized by the presence of a cell wall containing two layers, namely the ectocyst and the endocyst, mainly composed of cellulose and proteins. In the present work, we aimed to stimulate Acanthamoeba castellanii excystment by treating their cysts with a cellulolytic enzyme, i.e., cellulase, or two proteolytic enzymes, i.e., collagenase and pepsin. While 11 days were necessary to obtain total excystment in the control at 27°C, only 48 h were sufficient at the same temperature to obtain 100% trophozoites in the presence of 25 U/mL cellulase, 50 U/mL collagenase or 100 U/mL pepsin. Additionally, more than 96% amoebae have excysted after only 24 h with 7.5 U/mL cellulase at 30°C. Nevertheless, no effect of the three enzymes was observed on the excystment of Balamuthia mandrillaris and Vermamoeba vermiformis. Surprisingly, A. castellanii trophozoites excysted in the presence of cellulase displayed a markedly shorter doubling time at 7 h, in comparison to the control at 23 h. Likewise, trophozoites doubled their population in 9 h when both cellulose and cellulase were added to the medium, indicating that Acanthamoeba cyst wall degradation products promote their trophozoite proliferation. The analysis of cysts in epifluorescent microscopy using FITC-lectins and in electron microscopy revealed a disorganized endocyst and a reduction of the intercystic space area after cellulase treatment, implying that these cellular events are preliminary to trophozoite release during excystment. Further studies would be necessary to determine the signaling pathways involved during this amoebal differentiation process to identify new therapeutic targets for the development of anti-acanthamoebal drugs.
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Carvalho-Kelly LF, Dick CF, Rocco-Machado N, Gomes-Vieira AL, Paes-Vieira L, Meyer-Fernandes JR. Anaerobic ATP synthesis pathways and inorganic phosphate transport and their possible roles in encystment in Acanthamoeba castellanii. Cell Biol Int 2022; 46:1288-1298. [PMID: 35673988 DOI: 10.1002/cbin.11830] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 04/07/2022] [Accepted: 04/11/2022] [Indexed: 12/12/2022]
Abstract
Acanthamoeba castellanii is the etiological agent of amoebic keratitis and is present in the environment in trophozoite or cyst forms. Both forms can infect the vertebrate host and colonize different tissues. The high resistance of cysts to standard drugs used in clinics contributes to the lack of effective treatments. Therefore, in this context, studies have emerged to understand cyst physiology and metabolism. Phosphate transporters are proteins responsible for the uptake of extracellular inorganic phosphate and transport to the cytosol. This work aims to verify the relationship between Pi transport and energetic metabolism in cysts of A. castellanii. The phosphate uptake ratio was higher in cysts compared with trophozoites. Recently, three sequences related to phosphate transporters have been identified in the A. castellanii genome (AcPHS1, AcPHS2, and AcPHS3); the messenger RNA expression levels of which differ depending on the amoeba life form. Pi uptake in cysts displayed peak activity at alkaline pH, whereas Pi transport in trophozoites was not affected in the same pH ranges. Cysts harbor a low-affinity Pi transport system (K0,5 and Vmax values of 1.76 ± 0.26 mM and 104.6 ± 6.3 nmol Pi × h-1 × 106 cells) compared to the trophozoite phosphate transport system. Pi transport seems important for anaerobic adenosine triphosphate synthesis in cysts, which initially occurs through the glycolytic pathway and subsequently through the pyruvate ferredoxin oxidoreductase pathway. Altogether, these results suggest that contrary to that previously postulated, cysts are active metabolic forms, and, as noted in trophozoites, phosphate uptake is important for energetic metabolism.
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Affiliation(s)
| | - Claudia Fernanda Dick
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brasil
| | - Nathalia Rocco-Machado
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brasil
| | - André Luiz Gomes-Vieira
- Departamento de Bioquímica, Instituto de Química, Universidade Federal Rural do Rio de Janeiro, Seropédica, Brazil
| | - Lisvane Paes-Vieira
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brasil
| | - José Roberto Meyer-Fernandes
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brasil
- Institute of National Science and Technology of Structural Biology and Bioimage (INCTBEB), CCS, Bloco H, Cidade Universitária, Ilha do Fundão, Rio de Janeiro, Brazil
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20
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Siddiqui R, Makhlouf Z, Khan NA. The Increasing Importance of Vermamoeba vermiformis. J Eukaryot Microbiol 2021; 68:e12857. [PMID: 33987951 DOI: 10.1111/jeu.12857] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Vermamoeba vermiformis are one of the most prevalent free-living amoebae. These amoebae are ubiquitous and also thermotolerant. Of concern, V. vermiformis have been found in hospital water networks. Furthermore, associations between V. vermiformis and pathogenic bacteria have been reported, such as Legionella pneumophila. Moreover, V. vermiformis are well known to host viruses, bacteria, and other microorganisms and cases of keratitis due to V. vermiformis in conjunction with other amoebae have been reported. Despite the preceding, the medical importance of V. vermiformis is still an ongoing discussion and its genome has been only recently sequenced. Herein, we present a review of the current understanding of the biology and pathogenesis pertaining to V. vermiformis, as well as its' role as an etiological agent and trojan horse. An approach known as theranostics which combines both diagnosis and therapy could be utilized to eradicate and diagnose keratitis cases caused by such amoebae. Given the rise in global warming, it is imperative to investigate these rarely studied amoebae and to understand their importance in human health.
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Affiliation(s)
- Ruqaiyyah Siddiqui
- College of Arts and Sciences, American University of Sharjah, Sharjah, UAE
| | - Zinb Makhlouf
- College of Arts and Sciences, American University of Sharjah, Sharjah, UAE
| | - Naveed Ahmed Khan
- Department of Clinical Sciences, College of Medicine, University of Sharjah, Sharjah, UAE.,Research Institute for Medical and Health Sciences, University of Sharjah, Sharjah, UAE
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21
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Siddiqui R, Abouleish MY, Khamis M, Ibrahim T, Khan NA. Dual Targeting of Function-Structure for Effective Killing of Pathogenic Free-Living Amoebae. ACS Med Chem Lett 2021; 12:672-676. [PMID: 34055204 DOI: 10.1021/acsmedchemlett.1c00200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Here we discuss the potential value of targeting both the hardy structure of the cyst state of the parasite, in addition to the active trophozoite form, to provide target-directed inhibition as a viable drug strategy in the effective eradication of parasites.
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Affiliation(s)
| | | | | | | | - Naveed Ahmed Khan
- Department of Clinical Sciences, University of Sharjah, University City, Sharjah, United Arab Emirates
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22
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Mungroo MR, Tong T, Khan NA, Anuar TS, Maciver SK, Siddiqui R. Development of anti-acanthamoebic approaches. Int Microbiol 2021; 24:363-371. [PMID: 33754231 DOI: 10.1007/s10123-021-00171-3] [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: 12/30/2020] [Revised: 02/24/2021] [Accepted: 03/10/2021] [Indexed: 10/21/2022]
Abstract
Acanthamoeba keratitis is a sight-endangering eye infection, and causative organism Acanthamoeba presents a significant concern to public health, given escalation of contact lens wearers. Contemporary therapy is burdensome, necessitating prompt diagnosis and aggressive treatment. None of the contact lens disinfectants (local and international) can eradicate Acanthamoeba effectively. Using a range of compounds targeting cellulose, ion channels, and biochemical pathways, we employed bioassay-guided testing to determine their anti-amoebic effects. The results indicated that acarbose, indaziflam, terbuthylazine, glimepiride, inositol, vildagliptin and repaglinide showed anti-amoebic effects. Compounds showed minimal toxicity on human cells. Therefore, effects of the evaluated compounds after conjugation with nanoparticles should certainly be the subject of future studies and will likely lead to promising leads for potential applications.
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Affiliation(s)
- Mohammad Ridwane Mungroo
- Department of Biological Sciences, School of Medical and Life Sciences, Sunway University, Bandar Sunway, Selangor, Malaysia
| | - Tommy Tong
- Department of Biological Sciences, School of Medical and Life Sciences, Sunway University, Bandar Sunway, Selangor, Malaysia.
| | - Naveed Ahmed Khan
- Department of Clinical Sciences, College of Medicine, University of Sharjah, University City, Sharjah, United Arab Emirates.
| | - Tengku Shahrul Anuar
- Centre for Medical Laboratory Technology Studies, Faculty of Health Sciences, Universiti Teknologi MARA, Puncak Alam Campus, Shah Alam, Selangor, Malaysia
| | - Sutherland K Maciver
- Centre for Discovery Brain Science, Biomedical Sciences, Edinburgh Medical School, University of Edinburgh, Edinburgh, Scotland, UK
| | - Ruqaiyyah Siddiqui
- College of Arts and Sciences, American University of Sharjah, University City, Sharjah, United Arab Emirates
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Histone Deacetylase Inhibitors Enhance the Amoebicidal Effect of Low Concentration of Polyhexamethylene Biguanide by Inducing Apoptosis. Cornea 2020; 39:245-249. [PMID: 31724982 DOI: 10.1097/ico.0000000000002201] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
PURPOSE The aim of this study was to reduce the cytotoxicity and improve the amoebicidal effect of polyhexamethylene biguanide (PHMB) at low concentrations by combining it with histone deacetylase (HDAC) inhibitors. METHODS To reduce the cytotoxic effect on human corneal epithelial (HCE) cells, the concentration of PHMB was reduced to 0.0002%. To enhance the amoebicidal effect of PHMB, HDAC inhibitors such as suberoylanilide hydroxamic acid, MS275, or MC1568 were combined with it. Acanthamoeba and HCE cells were treated with 3 combinations to evaluate the amoebicidal and cytotoxic effects. Microscopy and fluorescence-activated cell sorting analysis were performed to investigate the apoptotic cell death of Acanthamoeba by these combinatorial treatments. RESULTS The low concentration of PHMB (0.0002%) alone demonstrated no cytopathic effects (CPEs) on HCE cells. Three combinatorial treatments using 0.0002% PHMB with 10 μM suberoylanilide hydroxamic acid, 10 μM MS275, or 10 μM MC1568 showed higher amoebicidal effects on A. castellanii trophozoites than PHMB alone. Fluorescence-activated cell sorting analysis confirmed that HDAC inhibitors increased the apoptotic cell death of Acanthamoeba. Mild CPEs were observed from HCE cells cotreated with PHMB and the HDAC inhibitors after 24 hours of exposure. CONCLUSIONS Combinatorial treatments showed high amoebicidal effects on Acanthamoeba and low CPEs on HCE cells, which suggests their potential application for Acanthamoeba keratitis treatment.
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Farrag HMM, Mostafa FAAM, Mohamed ME, Huseein EAM. Green biosynthesis of silver nanoparticles by Aspergillus niger and its antiamoebic effect against Allovahlkampfia spelaea trophozoite and cyst. Exp Parasitol 2020; 219:108031. [PMID: 33091422 DOI: 10.1016/j.exppara.2020.108031] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 10/18/2020] [Accepted: 10/18/2020] [Indexed: 01/11/2023]
Abstract
BACKGROUND Fungi represent an interesting candidate for the synthesis of nanoparticles. The biosynthesis of silver nanoparticles (AgNPs) has many industrial and biomedical indications. We aimed in this work to biologically synthesize silver nanoparticles using Aspergillus niger and to evaluate its effect against the newly identified Allovahlkampfia spelaea that causes resistant human keratitis. MATERIAL AND METHODS Aspergillus niger (soil isolate) was treated with silver nitrate to produce silver nanoparticles. AgNPs were characterized by Ultraviolet-Visible Spectroscopy, Transmission Electron Microscopy, and Fourier Transform Infrared Spectroscopy. The effect of the synthesized nanoparticles against Allovahlkampfia spelaea growth, encystation, excystation, and toxicity in host cells was evaluated. RESULTS AgNPs exhibited significant inhibition of Allovahlkampfia spelaea viability and growth of both trophozoites and cysts, with a reduction of amoebic cytotoxic activity in host cells. CONCLUSION AgNPs may give a promising future to the treatment of Allovahlkampfia spelaea infections in humans.
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Affiliation(s)
- Haiam Mohamed Mahmoud Farrag
- Department of Parasitology, Faculty of Medicine, Assiut University, Assiut, Egypt; Faculty of Applied Medical Sciences, Shaqra University, Saudi Arabia.
| | | | - Mona Embarek Mohamed
- Department of Medical Microbiology and Immunology, Faculty of Medicine, Assiut University, Assiut, Egypt
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Joo SY, Aung JM, Shin M, Moon EK, Kong HH, Goo YK, Chung DI, Hong Y. The role of the Acanthamoeba castellanii Sir2-like protein in the growth and encystation of Acanthamoeba. Parasit Vectors 2020; 13:368. [PMID: 32698828 PMCID: PMC7376869 DOI: 10.1186/s13071-020-04237-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2020] [Accepted: 07/15/2020] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND The encystation of Acanthamoeba leads to the development of resilient cysts from vegetative trophozoites. This process is essential for the survival of parasites under unfavorable conditions. Previous studies have reported that, during the encystation of A. castellanii, the expression levels of encystation-related factors are upregulated. However, the regulatory mechanisms for their expression during the encystation process remains unknown. Proteins in the sirtuin family, which consists of nicotinamide adenine dinucleotide-dependent deacetylases, are known to play an important role in various cellular functions. In the present study, we identified the Acanthamoeba silent-information regulator 2-like protein (AcSir2) and examined its role in the growth and encystation of Acanthamoeba. METHODS We obtained the full-length sequence for AcSir2 using reverse-transcription polymerase chain reaction. In Acanthamoeba transfectants that constitutively overexpress AcSir2 protein, SIRT deacetylase activity was measured, and the intracellular localization of AcSir2 and the effects on the growth and encystation of trophozoites were examined. In addition, the sirtuin inhibitor salermide was used to determine whether these effects were caused by AcSir2 overexpression RESULTS: AcSir2 was classified as a class-IV sirtuin. AcSir2 exhibited functional SIRT deacetylase activity, localized mainly in the nucleus, and its transcription was upregulated during encystation. In trophozoites, AcSir2 overexpression led to greater cell growth, and this growth was inhibited by treatment with salermide, a sirtuin inhibitor. When AcSir2 was overexpressed in the cysts, the encystation rate was significantly higher; this was also reversed with salermide treatment. In AcSir2-overexpressing encysting cells, the transcription of cellulose synthase was highly upregulated compared with that of control cells, and this upregulation was abolished with salermide treatment. Transmission electron microscope-based ultrastructural analysis of salermide-treated encysting cells showed that the structure of the exocyst wall and intercyst space was impaired and that the endocyst wall had not formed. CONCLUSIONS These results indicate that AcSir2 is a SIRT deacetylase that plays an essential role as a regulator of a variety of cellular processes and that the regulation of AcSir2 expression is important for the growth and encystation of A. castellanii.
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Affiliation(s)
- So-Young Joo
- Department of Parasitology and Tropical Medicine, School of Medicine, Kyungpook National University, Daegu, Republic of Korea
| | - Ja Moon Aung
- Department of Parasitology and Tropical Medicine, School of Medicine, Kyungpook National University, Daegu, Republic of Korea
| | - Minsang Shin
- Department of Microbiology, School of Medicine, Kyungpook National University, Daegu, Republic of Korea
| | - Eun-Kyung Moon
- Department of Medical Zoology, Kyung Hee University School of Medicine, Seoul, Republic of Korea
| | - Hyun-Hee Kong
- Department of Parasitology, Dong-A University College of Medicine, Busan, Republic of Korea
| | - Youn-Kyoung Goo
- Department of Parasitology and Tropical Medicine, School of Medicine, Kyungpook National University, Daegu, Republic of Korea
| | - Dong-Il Chung
- Department of Parasitology and Tropical Medicine, School of Medicine, Kyungpook National University, Daegu, Republic of Korea
| | - Yeonchul Hong
- Department of Parasitology and Tropical Medicine, School of Medicine, Kyungpook National University, Daegu, Republic of Korea.
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Baig AM, Khan NA, Katyara P, Lalani S, Baig R, Nadeem M, Akbar N, Nazim F, Khaleeq A. 'Targeting the feast of a sleeping beast': Nutrient and mineral dependencies of encysted Acanthamoeba castellanii. Chem Biol Drug Des 2020; 97:18-27. [PMID: 32602961 DOI: 10.1111/cbdd.13755] [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: 11/16/2019] [Revised: 06/02/2020] [Accepted: 06/05/2020] [Indexed: 11/28/2022]
Abstract
Acanthamoeba spp. cause a corneal infection, Acanthamoeba keratitis (AK), and a cerebral infection, granulomatous amoebic encephalitis (GAE). Though aggressive chemotherapy has been able to kill the active trophozoite form of Acanthamoeba, the encysted form of this parasite has remained problematic to resist physiological concentrations of drugs. The emergence of encysted amoeba into active trophozoite form poses a challenge to eradicate this parasite. Acanthamoeba trophozoites have active metabolic machinery that furnishes energy in the form of ATPs by subjecting carbohydrates and lipids to undergo pathways including glycolysis and beta-oxidation of free fatty acids, respectively. However, very little is known about the metabolic preferences and dependencies of an encysted trophozoite on minerals or potential nutrients that it consumes to live in an encysted state. Here, we investigate the metabolic and nutrient preferences of the encysted trophozoite of Acanthamoeba castellanii and the possibility to target them by drugs that act on calcium ion dependencies of the encysted amoeba. The experimental assays, immunostaining coupled with bioinformatics tools show that the encysted Acanthamoeba uses diverse nutrient pathways to obtain energy in the quiescent encysted state. These findings highlight potential pathways that can be targeted in eradicating amoebae cysts successfully.
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Affiliation(s)
- Abdul Mannan Baig
- Department of Biological and Biomedical Sciences, Aga Khan University, Karachi, Pakistan
| | - Naveed Ahmed Khan
- Department of Biology, Chemistry and Environmental Sciences, College of Arts and Sciences, American University of Sharjah, Sharjah, United Arab Emirates
| | - Preet Katyara
- Department of Biological and Biomedical Sciences, Aga Khan University, Karachi, Pakistan
| | - Salima Lalani
- Department of Virus and Vaccine Research, Biological and Biomedical Sciences, Bandar Sunway, Malaysia
| | - Rozeena Baig
- Department of Biological and Biomedical Sciences, Aga Khan University, Karachi, Pakistan
| | - Mehdia Nadeem
- Department of Biological and Biomedical Sciences, Aga Khan University, Karachi, Pakistan
| | - Noor Akbar
- Department of Biology, Chemistry and Environmental Sciences, College of Arts and Sciences, American University of Sharjah, Sharjah, United Arab Emirates
| | - Fizza Nazim
- Department of Biological and Biomedical Sciences, Aga Khan University, Karachi, Pakistan
| | - Areeba Khaleeq
- Department of Biological and Biomedical Sciences, Aga Khan University, Karachi, Pakistan
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Antiamoebic activity of 3-aryl-6,7-dimethoxyquinazolin-4(3H)-one library against Acanthamoeba castellanii. Parasitol Res 2020; 119:2327-2335. [PMID: 32476058 DOI: 10.1007/s00436-020-06710-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Accepted: 05/05/2020] [Indexed: 12/21/2022]
Abstract
Acanthamoeba castellanii is a free-living amoeba which can cause a blinding keratitis and fatal granulomatous amoebic encephalitis. The treatment of Acanthamoeba infections is challenging due to formation of cyst. Quinazolinones are medicinally important scaffold against parasitic diseases. A library of nineteen new 3-aryl-6,7-dimethoxyquinazolin-4(3H)-one derivatives was synthesized to evaluate their antiamoebic activity against Acanthamoeba castellanii. One-pot synthesis of 3-aryl-6,7-dimethoxyquinazolin-4(3H)-ones (1-19) was achieved by reaction of 2-amino-4,5-dimethoxybenzoic acid, trimethoxymethane, and different substituted anilines. These compounds were purified and characterized by standard chromatographic and spectroscopic techniques. Antiacanthamoebic activity of these compounds was determined by amoebicidal, encystation, excystation and host cell cytopathogenicity in vitro assays at concentrations of 50 and 100 μg/mL. The IC50 was found to be between 100 and 50 μg/mL for all the compounds except compound 5 which did not exhibit amoebicidal effects at these concentrations. Furthermore, lactate dehydrogenase assay was also performed to evaluate the in vitro cytotoxicity of these compounds against human keratinocyte (HaCaT) cells. The results revealed that eighteen out of nineteen derivatives of quinazolinones significantly decreased the viability of A. castellanii. Furthermore, eighteen out of nineteen tested compounds inhibited the encystation and excystation, as well as significantly reduced the A. castellanii-mediated cytopathogenicity against human cells. Interestingly, while tested against human normal cell line HaCaT keratinocytes, all compounds did not exhibit any overt cytotoxicity. Furthermore, a detailed structure-activity relationship is also studied to optimize the most potent hit from these synthetic compounds. This report presents several potential lead compounds belonging to 3-aryl-6,7-dimethoxyquinazolin-4(3H)-one derivatives for drug discovery against infections caused by Acanthamoeba castellanii.
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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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Effects of Shape and Size of Cobalt Phosphate Nanoparticles against Acanthamoeba castellanii. Pathogens 2019; 8:pathogens8040260. [PMID: 31766722 PMCID: PMC6963488 DOI: 10.3390/pathogens8040260] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Revised: 10/05/2019] [Accepted: 10/06/2019] [Indexed: 12/13/2022] Open
Abstract
T4 genotype Acanthamoeba are opportunistic pathogens that cause two types of infections, including vision-threatening Acanthamoeba keratitis (AK) and a fatal brain infection known as granulomatous amoebic encephalitis (GAE). Due to the existence of ineffective treatments against Acanthamoeba, it has become a potential threat to all contact lens users and immunocompromised patients. Metal nanoparticles have been proven to have various antimicrobial properties against bacteria, fungi, and parasites. Previously, different types of cobalt nanoparticles showed some promise as anti-acanthamoebic agents. In this study, the objectives were to synthesize and characterize the size, morphology, and crystalline structure of cobalt phosphate nanoparticles, as well as to determine the effects of different sizes of cobalt metal-based nanoparticles against A. castellanii. Cobalt phosphate octahydrate (CHP), Co3(PO4)2•8H2O, was synthesized by ultrasonication using a horn sonicator, then three different sizes of cobalt phosphates Co3(PO4)2 were produced through calcination of Co3(PO4)2•8H2O at 200 °C, 400 °C and 600 °C (CP2, CP4, CP6). These three types of cobalt phosphate nanoparticles were characterized using a field emission scanning electron microscope (FESEM), energy dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD) analysis. Next, the synthesized nanoparticles were subjected to biological assays to investigate their amoebicidal, amoebistatic, anti-encystation, and anti-excystation effects against A. castellanii, as well as cell cytotoxicity. The overall results showed that 1.30 ± 0.70 µm of CHP microflakes demonstrated the best anti-acanthemoebic effects at 100 µg/mL, followed by 612.50 ± 165.94 nm large CP6 nanograins. However, amongst the three tested cobalt phosphates, Co3(PO4)2, the smaller nanoparticles had stronger antiamoebic effects against A. castellanii. During cell cytotoxicity analysis, CHP exhibited only 15% cytotoxicity against HeLa cells, whereas CP6 caused 46% (the highest) cell cytotoxicity at the highest concentration, respectively. Moreover, the composition and morphology of nanoparticles is suggested to be important in determining their anti-acathamoebic effects. However, the molecular mechanisms of cobalt phosphate nanoparticles are still unidentified. Nevertheless, the results suggested that cobalt phosphate nanoparticles hold potential for development of nanodrugs against Acanthamoeba.
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Siddiqui R, Roberts SK, Ong TYY, Mungroo MR, Anwar A, Khan NA. Novel insights into the potential role of ion transport in sensory perception in Acanthamoeba. Parasit Vectors 2019; 12:538. [PMID: 31727139 PMCID: PMC6857129 DOI: 10.1186/s13071-019-3785-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2019] [Accepted: 11/04/2019] [Indexed: 11/25/2022] Open
Abstract
Background Acanthamoeba is well known to produce a blinding keratitis and serious brain infection known as encephalitis. Effective treatment is problematic, and can continue up to a year, and even then, recurrence can ensue. Partly, this is due to the capability of vegetative amoebae to convert into resistant cysts. Cysts can persist in an inactive form for decades while retaining their pathogenicity. It is not clear how Acanthamoeba cysts monitor environmental changes, and determine favourable conditions leading to their emergence as viable trophozoites. Methods The role of ion transporters in the encystation and excystation of Acanthamoeba remains unclear. Here, we investigated the role of sodium, potassium and calcium ion transporters as well as proton pump inhibitors on A. castellanii encystation and excystation and their effects on trophozoites. Results Remarkably 3′,4′-dichlorobenzamil hydrochloride a sodium–calcium exchange inhibitor, completely abolished excystation of Acanthamoeba. Furthermore, lanthanum oxide and stevioside hydrate, both potassium transport inhibitors, resulted in the partial inhibition of Acanthamoeba excystation. Conversely, none of the ion transport inhibitors affected encystation or had any effects on Acanthamoeba trophozoites viability. Conclusions The present study indicates that ion transporters are involved in sensory perception of A. castellanii suggesting their value as potential therapeutic targets to block cellular differentiation that presents a significant challenge in the successful prognosis of Acanthamoeba infections.
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Affiliation(s)
- Ruqaiyyah Siddiqui
- Department of Biology, Chemistry and Environmental Sciences, College of Arts and Sciences, American University of Sharjah, University City, Sharjah, United Arab Emirates.
| | | | - Timothy Yu Yee Ong
- Department of Biological Sciences, School of Science and Technology, Sunway University, Bandar Sunway, Malaysia
| | - Mohammad Ridwane Mungroo
- Department of Biological Sciences, School of Science and Technology, Sunway University, Bandar Sunway, Malaysia
| | - Areeba Anwar
- Department of Biological Sciences, School of Science and Technology, Sunway University, Bandar Sunway, Malaysia
| | - 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
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Anwar A, Shahbaz MS, Saad SM, Kanwal, Khan KM, Siddiqui R, Khan NA. Novel antiacanthamoebic compounds belonging to quinazolinones. Eur J Med Chem 2019; 182:111575. [DOI: 10.1016/j.ejmech.2019.111575] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 07/29/2019] [Accepted: 07/30/2019] [Indexed: 12/11/2022]
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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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Anwar A, Siddiqui R, Hameed A, Shah MR, Khan NA. Synthetic Dihydropyridines as Novel Antiacanthamoebic Agents. Med Chem 2019; 16:841-847. [PMID: 31544702 DOI: 10.2174/1573406415666190722113412] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Revised: 07/09/2019] [Accepted: 07/10/2019] [Indexed: 11/22/2022]
Abstract
BACKGROUND Acanthamoeba is an opportunistic pathogen widely spread in the environment. Acanthamoeba causes excruciating keratitis which can lead to blindness. The lack of effective drugs and its ability to form highly resistant cyst are one of the foremost limitations against successful prognosis. Current treatment involves mixture of drugs at high doses but still recurrence of infection can occur due to ineffectiveness of drugs against the cyst form. Pyridine and its natural and synthetic derivatives are potential chemotherapeutic agents due to their diverse biological activities. OBJECTIVE To study the antiamoebic effects of four novel synthetic dihydropyridine (DHP) compounds against Acanthamoeba castellanii belonging to the T4 genotype. Furthermore, to evaluate their activity against amoeba-mediated host cells cytopathogenicity as well as their cytotoxicity against human cells. METHODS Dihydropyridines were synthesized by cyclic dimerization of alkylidene malononitrile derivatives. Four analogues of functionally diverse DHPs were tested against Acanthamoeba castellanii by using amoebicidal, encystation and excystation assays. Moreover, Lactate dehydrogenase assays were carried out to study cytopathogenicity and cytotoxicity against human cells. RESULTS These compounds showed significant amoebicidal and cysticidal effects at 50 μM concentration, whereas, two of the DHP derivatives also significantly reduced Acanthamoebamediated host cell cytotoxicity. Moreover, these DHPs were found to have low cytotoxicity against human cells suggesting a good safety profile. CONCLUSION The results suggest that DHPs have potential against Acanthamoeba especially against the more resistant cyst stage and can be assessed further for drug development.
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Affiliation(s)
- Ayaz Anwar
- Department of Biological Sciences, School of Science and Technology, Sunway University, Petaling Jaya 47500, Selangor, Malaysia
| | - Ruqaiyyah Siddiqui
- Department of Biology, Chemistry and Environmental Sciences, American University of Sharjah, Sharjah 26666, Malaysia
| | - Abdul Hameed
- Department of Chemistry, Forman Christian College, Lahore 54600, Punjab, Pakistan
| | - Muhammad R Shah
- HEJ Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi 75270, Pakistan
| | - Naveed A Khan
- Department of Biology, Chemistry and Environmental Sciences, American University of Sharjah, Sharjah 26666, Malaysia
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Affiliation(s)
- Ayaz Anwar
- Department of Biological Sciences, School of Science and Technology, Sunway University, Subang Jaya, Selangor, Malaysia
- * E-mail:
| | - Naveed A. Khan
- Department of Biological Sciences, School of Science and Technology, Sunway University, Subang Jaya, Selangor, Malaysia
| | - Ruqaiyyah Siddiqui
- Department of Biological Sciences, School of Science and Technology, Sunway University, Subang Jaya, Selangor, Malaysia
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Anwar A, Numan A, Siddiqui R, Khalid M, Khan NA. Cobalt nanoparticles as novel nanotherapeutics against Acanthamoeba castellanii. Parasit Vectors 2019; 12:280. [PMID: 31159839 PMCID: PMC6545699 DOI: 10.1186/s13071-019-3528-2] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Accepted: 05/23/2019] [Indexed: 12/17/2022] Open
Abstract
Background Species of Acanthamoeba are facultative pathogens which can cause sight threatening Acanthamoeba keratitis and a rare but deadly brain infection, granulomatous amoebic encephalitis. Due to conversion of Acanthamoeba trophozoites to resistant cyst stage, most drugs are found to be ineffective at preventing recurrence of infection. This study was designed to test the antiacanthamoebic effects of different cobalt nanoparticles (CoNPs) against trophozoites and cysts, as well as parasite-mediated host cell cytotoxicity. Methods Three different varieties of CoNPs were synthesized by utilizing hydrothermal and ultrasonication methods and were thoroughly characterized by X-ray diffraction and field emission scanning electron microscopy. Amoebicidal, encystation, excystation, and host cell cytopathogenicity assays were conducted to study the antiacanthamoebic effects of CoNPs. Results The results of the antimicrobial evaluation revealed that cobalt phosphate Co3(PO4)2 hexagonal microflakes, and 100 nm large cobalt hydroxide (Co(OH)2) nanoflakes showed potent amoebicidal activity at 100 and 10 µg/ml against Acanthamoeba castellanii as compared to granular cobalt oxide (Co3O4) of size 35–40 nm. Furthermore, encystation and excystation assays also showed consistent inhibition at 100 µg/ml. CoNPs also inhibited amoebae-mediated host cell cytotoxicity as determined by lactate dehydrogenase release without causing significant damage to human cells when treated alone. Conclusions To our knowledge, these findings determined, for the first time, the effects of composition, size and morphology of CoNPs against A. castellanii. Co3(PO4)2 hexagonal microflakes showed the most promising antiamoebic effects as compared to Co(OH)2 nanoflakes and granular Co3O4. The results reported in the present study hold potential for the development of antiamoebic nanomedicine.
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Affiliation(s)
- Ayaz Anwar
- Department of Biological Sciences, School of Science and Technology, Sunway University, 47500, Subang Jaya, Selangor, Malaysia.
| | - Arshid Numan
- Graphene and Advanced 2D Materials Research Group, School of Science and Technology, Sunway University, 47500, Subang Jaya, Selangor, Malaysia
| | - Ruqaiyyah Siddiqui
- Department of Biological Sciences, School of Science and Technology, Sunway University, 47500, Subang Jaya, Selangor, Malaysia
| | - Mohammad Khalid
- Graphene and Advanced 2D Materials Research Group, School of Science and Technology, Sunway University, 47500, Subang Jaya, Selangor, Malaysia
| | - Naveed Ahmed Khan
- Department of Biological Sciences, School of Science and Technology, Sunway University, 47500, Subang Jaya, Selangor, Malaysia
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Magistrado-Coxen P, Aqeel Y, Lopez A, Haserick JR, Urbanowicz BR, Costello CE, Samuelson J. The most abundant cyst wall proteins of Acanthamoeba castellanii are lectins that bind cellulose and localize to distinct structures in developing and mature cyst walls. PLoS Negl Trop Dis 2019; 13:e0007352. [PMID: 31095564 PMCID: PMC6541295 DOI: 10.1371/journal.pntd.0007352] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 05/29/2019] [Accepted: 04/01/2019] [Indexed: 12/02/2022] Open
Abstract
Background Acanthamoeba castellanii, which causes keratitis and blindness in under-resourced countries, is an emerging pathogen worldwide, because of its association with contact lens use. The wall makes cysts resistant to sterilizing reagents in lens solutions and to antibiotics applied to the eye. Methodology/Principal findings Transmission electron microscopy and structured illumination microscopy (SIM) showed purified cyst walls of A. castellanii retained an outer ectocyst layer, an inner endocyst layer, and conical ostioles that connect them. Mass spectrometry showed candidate cyst wall proteins were dominated by three families of lectins (named here Jonah, Luke, and Leo), which bound well to cellulose and less well to chitin. An abundant Jonah lectin, which has one choice-of-anchor A (CAA) domain, was made early during encystation and localized to the ectocyst layer of cyst walls. An abundant Luke lectin, which has two carbohydrate-binding modules (CBM49), outlined small, flat ostioles in a single-layered primordial wall and localized to the endocyst layer and ostioles of mature walls. An abundant Leo lectin, which has two unique domains with eight Cys residues each (8-Cys), localized to the endocyst layer and ostioles. The Jonah lectin and glycopolymers, to which it binds, were accessible in the ectocyst layer. In contrast, Luke and Leo lectins and the glycopolymers, to which they bind, were mostly inaccessible in the endocyst layer and ostioles. Conclusions/Significance The most abundant A. castellanii cyst wall proteins are three sets of lectins, which have carbohydrate-binding modules that are conserved (CBM49s of Luke), newly characterized (CAA of Jonah), or unique to Acanthamoebae (8-Cys of Leo). Cyst wall formation is a tightly choreographed event, in which lectins and glycopolymers combine to form a mature wall with a protected endocyst layer. Because of its accessibility in the ectocyst layer, an abundant Jonah lectin is an excellent diagnostic target. A half century ago, investigators identified cellulose in the Acanthamoeba cyst wall, which has two layers and conical ostioles that connect them. Here we showed cyst walls contain three large sets of cellulose-binding lectins, which localize to the ectocyst layer (a Jonah lectin) or to the endocyst layer and ostioles (Luke and Leo lectins). We used the lectins to establish a sequence for cyst wall assembly when trophozoites are starved and encyst. In the first stage, a Jonah lectin and glycopolymers were present in dozens of distinct vesicles. In the second stage, a primordial wall contained small, flat ostioles outlined by a Luke lectin. In the third stage, a Jonah lectin remained in the ectocyst layer, while Luke and Leo lectins moved to the endocyst layer and ostioles. A description of the major events during cyst wall development is a starting point for mechanistic studies of its assembly.
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Affiliation(s)
- Pamela Magistrado-Coxen
- Department of Molecular and Cell Biology, Boston University Goldman School of Dental Medicine, Boston, Massachusetts, United States of America
| | - Yousuf Aqeel
- Department of Molecular and Cell Biology, Boston University Goldman School of Dental Medicine, Boston, Massachusetts, United States of America
| | - Angelo Lopez
- Department of Molecular and Cell Biology, Boston University Goldman School of Dental Medicine, Boston, Massachusetts, United States of America
- Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - John R. Haserick
- Department of Molecular and Cell Biology, Boston University Goldman School of Dental Medicine, Boston, Massachusetts, United States of America
- Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - Breeanna R. Urbanowicz
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, United States of America
| | - Catherine E. Costello
- Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - John Samuelson
- Department of Molecular and Cell Biology, Boston University Goldman School of Dental Medicine, Boston, Massachusetts, United States of America
- * E-mail:
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Anwar A, Abdalla SAO, Aslam Z, Shah MR, Siddiqui R, Khan NA. Oleic acid-conjugated silver nanoparticles as efficient antiamoebic agent against Acanthamoeba castellanii. Parasitol Res 2019; 118:2295-2304. [PMID: 31093751 DOI: 10.1007/s00436-019-06329-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Accepted: 04/16/2019] [Indexed: 12/11/2022]
Abstract
Acanthamoeba castellanii belonging to the T4 genotype is an opportunistic pathogen which is associated with blinding eye keratitis and rare but fatal central nervous system infection. A. castellanii pose serious challenges in antimicrobial chemotherapy due to its ability to convert into resistant, hardy shell-protected cyst form that leads to infection recurrence. The fatty acid composition of A. castellanii trophozoites is known to be most abundant in oleic acid which chemically is an unsaturated cis-9-Octadecanoic acid and naturally found in animal and vegetable fats and oils. This study was designed to evaluate antiacanthamoebic effects of oleic acid against trophozoites, cysts as well as parasite-mediated host cell cytotoxicity. Moreover, oleic acid-conjugated silver nanoparticles (AgNPs) were also synthesized and tested against A. castellanii. Oleic acid-AgNPs were synthesized by chemical reduction method and characterized by ultraviolet-visible spectrophotometry, atomic force microscopy, dynamic light scattering analysis, and Fourier transform infrared spectroscopy. Viability, growth inhibition, encystation, and excystation assays were performed with 10 and 5 μM concentration of oleic acid alone and oleic acid-conjugated AgNPs. Bioassays revealed that oleic acid alone and oleic acid-conjugated AgNPs exhibited significant antiamoebic properties, whereas nanoparticle conjugation further enhanced the efficacy of oleic acid. Phenotype differentiation assays also showed significant inhibition of encystation and excystation at 5 μM. Furthermore, oleic acid and oleic acid-conjugated AgNPs also inhibited amoebae-mediated host cell cytotoxicity as determined by lactate dehydrogenase release. These findings for the first time suggest that oleic acid-conjugated AgNPs exhibit antiacanthamoebic activity that hold potential for therapeutic applications against A. castellanii.
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Affiliation(s)
- Ayaz Anwar
- Department of Biological Sciences, School of Science and Technology, Sunway University, 47500, Subang Jaya, Selangor, Malaysia.
| | | | - Zara Aslam
- HEJ Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi, 75270, Pakistan
| | - Muhammad Raza Shah
- HEJ Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi, 75270, Pakistan
| | - Ruqaiyyah Siddiqui
- Department of Biological Sciences, School of Science and Technology, Sunway University, 47500, Subang Jaya, Selangor, Malaysia
| | - Naveed Ahmed Khan
- Department of Biological Sciences, School of Science and Technology, Sunway University, 47500, Subang Jaya, Selangor, Malaysia
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Garajová M, Mrva M, Vaškovicová N, Martinka M, Melicherová J, Valigurová A. Cellulose fibrils formation and organisation of cytoskeleton during encystment are essential for Acanthamoeba cyst wall architecture. Sci Rep 2019; 9:4466. [PMID: 30872791 PMCID: PMC6418277 DOI: 10.1038/s41598-019-41084-6] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2018] [Accepted: 03/01/2019] [Indexed: 01/26/2023] Open
Abstract
Acanthamoebae success as human pathogens is largely due to the highly resistant cysts which represent a crucial problem in treatment of Acanthamoeba infections. Hence, the study of cyst wall composition and encystment play an important role in finding new therapeutic strategies. For the first time, we detected high activity of cytoskeletal elements - microtubular networks and filamentous actin, in late phases of encystment. Cellulose fibrils - the main components of endocyst were demonstrated in inter-cystic space, and finally in the ectocyst, hereby proving the presence of cellulose in both layers of the cyst wall. We detected clustering of intramembranous particles (IMPs) and their density alterations in cytoplasmic membrane during encystment. We propose a hypothesis that in the phase of endocyst formation, the IMP clusters represent cellulose microfibril terminal complexes involved in cellulose synthesis that after cyst wall completion are reduced. Cyst wall impermeability, due largely to a complex polysaccharide (glycans, mainly cellulose) has been shown to be responsible for Acanthamoeba biocide resistance and cellulose biosynthesis pathway is suggested to be a potential target in treatment of Acanthamoeba infections. Disruption of this pathway would affect the synthesis of cyst wall and reduce considerably the resistance to chemotherapeutic agents.
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Affiliation(s)
- Mária Garajová
- Department of Zoology, Faculty of Natural Sciences, Comenius University in Bratislava, 842 15, Bratislava, Slovak Republic.
| | - Martin Mrva
- Department of Zoology, Faculty of Natural Sciences, Comenius University in Bratislava, 842 15, Bratislava, Slovak Republic
| | - Naděžda Vaškovicová
- Institute of Scientific Instruments, Czech Academy of Sciences, 612 64, Brno, Czech Republic
| | - Michal Martinka
- Department of Plant Physiology, Faculty of Natural Sciences, Comenius University in Bratislava, 842 15, Bratislava, Slovak Republic
| | - Janka Melicherová
- Department of Botany and Zoology, Faculty of Science, Masaryk University, 611 37, Brno, Czech Republic
| | - Andrea Valigurová
- Department of Botany and Zoology, Faculty of Science, Masaryk University, 611 37, Brno, Czech Republic
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Anwar A, Masri A, Rao K, Rajendran K, Khan NA, Shah MR, Siddiqui R. Antimicrobial activities of green synthesized gums-stabilized nanoparticles loaded with flavonoids. Sci Rep 2019; 9:3122. [PMID: 30816269 PMCID: PMC6395601 DOI: 10.1038/s41598-019-39528-0] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2018] [Accepted: 01/18/2019] [Indexed: 01/09/2023] Open
Abstract
Herein, we report green synthesized nanoparticles based on stabilization by plant gums, loaded with citrus fruits flavonoids Hesperidin (HDN) and Naringin (NRG) as novel antimicrobial agents against brain-eating amoebae and multi-drug resistant bacteria. Nanoparticles were thoroughly characterized by using zetasizer, zeta potential, atomic force microscopy, ultravoilet-visible and Fourier transform-infrared spectroscopic techniques. The size of these spherical nanoparticles was found to be in the range of 100-225 nm. The antiamoebic effects of these green synthesized Silver and Gold nanoparticles loaded with HDN and NRG were tested against Acanthamoeba castellanii and Naegleria fowleri, while antibacterial effects were evaluated against methicillin-resistant Staphylococcus aureus (MRSA) and neuropathogenic Escherichia coli K1. Amoebicidal assays revealed that HDN loaded Silver nanoparticles stabilized by gum acacia (GA-AgNPs-HDN) quantitatively abolished amoeba viability by 100%, while NRG loaded Gold nanoparticles stabilized by gum tragacanth (GT-AuNPs-NRG) significantly reduced the viability of A. castellanii and N. fowleri at 50 µg per mL. Furthermore, these nanoparticles inhibited the encystation and excystation by more than 85%, as well as GA-AgNPs-HDN only completely obliterated amoeba-mediated host cells cytopathogenicity. Whereas, GA-AgNPs-HDN exhibited significant bactericidal effects against MRSA and E. coli K1 and reduced bacterial-mediated host cells cytotoxicity. Notably, when tested against human cells, these nanoparticles showed minimal (23%) cytotoxicity at even higher concentration of 100 µg per mL as compared to 50 µg per mL used for antimicrobial assays. Hence, these novel nanoparticles formulations hold potential as therapeutic agents against infections caused by brain-eating amoebae, as well as multi-drug resistant bacteria, and recommend a step forward in drug development.
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Affiliation(s)
- Ayaz Anwar
- Department of Biological Sciences, School of Science and Technology, Sunway University, Subang Jaya, 47500, Selangor, Malaysia.
| | - Abdulkader Masri
- Department of Biological Sciences, School of Science and Technology, Sunway University, Subang Jaya, 47500, Selangor, Malaysia
| | - Komal Rao
- H.E.J. Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi, 75270, Pakistan
| | - Kavitha Rajendran
- Department of Biological Sciences, School of Science and Technology, Sunway University, Subang Jaya, 47500, Selangor, Malaysia
| | - Naveed Ahmed Khan
- Department of Biological Sciences, School of Science and Technology, Sunway University, Subang Jaya, 47500, Selangor, Malaysia
| | - Muhammad Raza Shah
- H.E.J. Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi, 75270, Pakistan
| | - Ruqaiyyah Siddiqui
- Department of Biological Sciences, School of Science and Technology, Sunway University, Subang Jaya, 47500, Selangor, Malaysia
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Anwar A, Rajendran K, Siddiqui R, Raza Shah M, Khan NA. Clinically Approved Drugs against CNS Diseases as Potential Therapeutic Agents To Target Brain-Eating Amoebae. ACS Chem Neurosci 2019; 10:658-666. [PMID: 30346711 DOI: 10.1021/acschemneuro.8b00484] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Central nervous system (CNS) infections caused by free-living amoebae such as Acanthamoeba species and Naegleria fowleri are rare but fatal. A major challenge in the treatment against the infections caused by these amoebae is the discovery of novel compounds that can effectively cross the blood-brain barrier to penetrate the CNS. It is logical to test clinically approved drugs against CNS diseases for their potential antiamoebic effects since they are known for effective blood-brain barrier penetration and affect eukaryotic cell targets. The antiamoebic effects of clinically available drugs for seizures targeting gamma-amino butyric acid (GABA) receptor and ion channels were tested against Acanthamoeba castellanii belonging to the T4 genotype and N. fowleri. Three such drugs, namely, diazepam (Valium), phenobarbitone (Luminal), phenytoin (Dilantin), and their silver nanoparticles (AgNPs) were evaluated against both trophozoites and cysts stage. Drugs alone and drug conjugated silver nanoparticles were tested for amoebicidal, cysticidal, and host-cell cytotoxicity assays. Nanoparticles were synthesized by sodium borohydride reduction of silver nitrate with drugs as capping agents. Drug conjugated nanoconjugates were characterized by ultraviolet-visible (UV-vis) and Fourier transform infrared (FT-IR) spectroscopies and atomic force microscopy (AFM). In vitro moebicidal assay showed potent amoebicidal effects for diazepam, phenobarbitone, and phenytoin-conjugated AgNPs as compared to drugs alone against A. castellanii and N. fowleri. Furthermore, both drugs and drug conjugated AgNPs showed compelling cysticidal effects. Drugs conjugations with silver nanoparticles enhanced their antiacanthamoebic activity. Interestingly, amoeba-mediated host-cell cytotoxicity was also significantly reduced by drugs alone as well as their nanoconjugates. Since, these drugs are being used to target CNS diseases, their evaluation against brain-eating amoebae seems feasible due to advantages such as permeability of the blood-brain barrier, established pharmacokinetics and dynamics, and United States Food and Drug Administration (FDA) approval. Given the limited availability of effective drugs against brain-eating amoebae, the clinically available drugs tested here present potential for further in vivo studies.
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Affiliation(s)
- Ayaz Anwar
- Department of Biological Sciences, School of Science and Technology, Sunway University, Selangor 47500, Malaysia
| | - Kavitha Rajendran
- Department of Biological Sciences, School of Science and Technology, Sunway University, Selangor 47500, Malaysia
| | - Ruqaiyyah Siddiqui
- Department of Biological Sciences, School of Science and Technology, Sunway University, Selangor 47500, Malaysia
| | - Muhammad Raza Shah
- HEJ Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi 75270, Pakistan
| | - Naveed Ahmed Khan
- Department of Biological Sciences, School of Science and Technology, Sunway University, Selangor 47500, Malaysia
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Gold Nanoparticle-Conjugated Cinnamic Acid Exhibits Antiacanthamoebic and Antibacterial Properties. Antimicrob Agents Chemother 2018; 62:AAC.00630-18. [PMID: 29967024 DOI: 10.1128/aac.00630-18] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Accepted: 06/22/2018] [Indexed: 01/10/2023] Open
Abstract
trans-Cinnamic acid (CA) is a natural organic compound. Using amoebicidal assays, for the first time we showed that CA affected the viability of the protist pathogen Acanthamoeba castellanii Conjugation with gold nanoparticles (AuNPs) enhanced the antiamoebic effects of CA. CA-coated AuNPs (CA-AuNPs) also exhibited significant excystation and encystation activity, compared to CA and AuNPs alone. Pretreatment of amoebae with CA-AuNPs inhibited A. castellanii-mediated host cell cytotoxicity. Moreover, CA-AuNPs exhibited potent effects against methicillin-resistant Staphylococcus aureus and neuropathogenic Escherichia coli K1 and protected host cells against bacteria-mediated host cell death.
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Jarvis MC. Structure of native cellulose microfibrils, the starting point for nanocellulose manufacture. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2018; 376:rsta.2017.0045. [PMID: 29277742 DOI: 10.1098/rsta.2017.0045] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 07/05/2017] [Indexed: 05/04/2023]
Abstract
There is an emerging consensus that higher plants synthesize cellulose microfibrils that initially comprise 18 chains. However, the mean number of chains per microfibril in situ is usually greater than 18, sometimes much greater. Microfibrils from woody tissues of conifers, grasses and dicotyledonous plants, and from organs like cotton hairs, all differ in detailed structure and mean diameter. Diameters increase further when aggregated microfibrils are isolated. Because surface chains differ, the tensile properties of the cellulose may be augmented by increasing microfibril diameter. Association of microfibrils with anionic polysaccharides in primary cell walls and mucilages leads to in vivo mechanisms of disaggregation that may be relevant to the preparation of nanofibrillar cellulose products. For the preparation of nanocrystalline celluloses, the key issue is the nature and axial spacing of disordered domains at which axial scission can be initiated. These disordered domains do not, as has often been suggested, take the form of large blocks occupying much of the length of the microfibril. They are more likely to be located at chain ends or at places where the microfibril has been mechanically damaged, but their structure and the reasons for their sensitivity to acid hydrolysis need better characterization.This article is part of a discussion meeting issue 'New horizons for cellulose nanotechnology'.
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Affiliation(s)
- Michael C Jarvis
- College of Science and Engineering, University of Glasgow, Glasgow G12 8QQ, UK
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Anwar A, Khan NA, Siddiqui R. Combating Acanthamoeba spp. cysts: what are the options? Parasit Vectors 2018; 11:26. [PMID: 29316961 PMCID: PMC5759203 DOI: 10.1186/s13071-017-2572-z] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Accepted: 12/05/2017] [Indexed: 11/29/2022] Open
Abstract
Acanthamoeba spp. are protist pathogens and causative agents of serious infections including keratitis and granulomatous amoebic encephalitis. Its ability to convert into dormant and highly resistant cysts form limits effectiveness of available therapeutic agents and presents a pivotal challenge for drug development. During the cyst stage, Acanthamoeba is protected by the presence of hardy cyst walls, comprised primarily of carbohydrates and cyst-specific proteins, hence synthesis inhibition and/or degradation of cyst walls is of major interest. This review focuses on targeting of Acanthamoeba cysts by identifying viable therapeutic targets.
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Affiliation(s)
- Ayaz Anwar
- Department of Biological Sciences, School of Science and Technology, Sunway University, Subang Jaya, Malaysia
| | - Naveed Ahmed Khan
- Department of Biological Sciences, School of Science and Technology, Sunway University, Subang Jaya, Malaysia.
| | - Ruqaiyyah Siddiqui
- Department of Biological Sciences, School of Science and Technology, Sunway University, Subang Jaya, Malaysia
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Siddiqui R, Abjani F, Yeo CI, Tiekink ERT, Khan NA. The effects of phosphanegold(I) thiolates on the biological properties of Acanthamoeba castellanii belonging to the T4 genotype. J Negat Results Biomed 2017; 16:6. [PMID: 28366172 PMCID: PMC5376697 DOI: 10.1186/s12952-017-0070-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Accepted: 02/09/2017] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Gold compounds have shown promise in the treatment of non-communicable diseases such as rheumatoid arthritis and cancer, and are considered of value as anti-microbial agents against Gram-negative and Gram-positive bacteria, and have anti-parasitic properties against Schistosoma mansoni, Trypanosoma brucei, Plasmodium falciparum, Leishmania infantinum, Giardia lamblia, and Entamoeba histolytica. They are known to affect enzymatic activities that are required for the cellular respiration processes. METHODS Anti-amoebic effects of phosphanegold(I) thiolates were tested against clinical isolate of A. castellanii belonging to the T4 genotype by employing viability assays, growth inhibition assays, encystation assays, excystation assays, and zymographic assays. RESULTS The treatment of A. castellanii with the phosphanegold(I) thiolates tested (i) had no effect on the viability of A. castellanii as determined by Trypan blue exclusion test, (ii) did not affect amoebae growth using PYG growth medium, (iii) did not inhibit cellular differentiation, and (iv) had no effect on the extracellular proteolytic activities of A. castellanii. CONCLUSION Being free-living amoeba, A. castellanii is a versatile respirator and possesses respiratory mechanisms that adapt to various aerobic and anaerobic environments to avoid toxic threats and adverse conditions. For the first time, our findings showed that A. castellanii exhibits resistance to the toxic effects of gold compounds and could prove to be an attractive model to study mechanisms of metal resistance in eukaryotic cells.
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Affiliation(s)
- Ruqaiyyah Siddiqui
- Department of Biological Sciences, Faculty of Science and Technology, Sunway University, 47500 Bandar Sunway, Selangor, Malaysia
| | - Farhat Abjani
- Department of Biological Sciences, Faculty of Science and Technology, Sunway University, 47500 Bandar Sunway, Selangor, Malaysia
| | - Chien Ing Yeo
- Research Centre for Crystalline Materials, Sunway University, 47500 Bandar Sunway, Selangor, Malaysia
| | - Edward R T Tiekink
- Research Centre for Crystalline Materials, Sunway University, 47500 Bandar Sunway, Selangor, Malaysia
| | - Naveed Ahmed Khan
- Department of Biological Sciences, Faculty of Science and Technology, Sunway University, 47500 Bandar Sunway, Selangor, Malaysia.
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Abjani F, Khan NA, Yousuf FA, Siddiqui R. Targeting cyst wall is an effective strategy in improving the efficacy of marketed contact lens disinfecting solutions against Acanthamoeba castellanii cysts. Cont Lens Anterior Eye 2016; 39:239-43. [DOI: 10.1016/j.clae.2015.11.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Revised: 10/29/2015] [Accepted: 11/24/2015] [Indexed: 10/22/2022]
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The use of dimethyl sulfoxide in contact lens disinfectants is a potential preventative strategy against contracting Acanthamoeba keratitis. Cont Lens Anterior Eye 2016; 39:389-93. [PMID: 27133448 DOI: 10.1016/j.clae.2016.04.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Revised: 04/11/2016] [Accepted: 04/17/2016] [Indexed: 11/23/2022]
Abstract
Acanthamoeba castellanii is the causative agent of blinding keratitis. Though reported in non-contact lens wearers, it is most frequently associated with improper use of contact lens. For contact lens wearers, amoebae attachment to the lens is a critical first step, followed by amoebae binding to the corneal epithelial cells during extended lens wear. Acanthamoeba attachment to surfaces (biological or inert) and migration is an active process and occurs during the trophozoite stage. Thus retaining amoebae in the cyst stage (dormant form) offers an added preventative measure in impeding parasite traversal from the contact lens onto the cornea. Here, we showed that as low as 3% DMSO, abolished A. castellanii excystation. Based on the findings, it is proposed that DMSO should be included in the contact lens disinfectants as an added preventative strategy against contracting Acanthamoeba keratitis.
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Potential Value of Cellulose Synthesis Inhibitors Combined With PHMB in the Treatment of Acanthamoeba Keratitis. Cornea 2015; 34:1593-8. [DOI: 10.1097/ico.0000000000000642] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Lakhundi S, Siddiqui R, Khan NA. Cellulose degradation: a therapeutic strategy in the improved treatment of Acanthamoeba infections. Parasit Vectors 2015; 8:23. [PMID: 25586209 PMCID: PMC4300153 DOI: 10.1186/s13071-015-0642-7] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Accepted: 01/05/2015] [Indexed: 11/10/2022] Open
Abstract
Acanthamoeba is an opportunistic free-living amoeba that can cause blinding keratitis and fatal brain infection. Early diagnosis, followed by aggressive treatment is a pre-requisite in the successful treatment but even then the prognosis remains poor. A major drawback during the course of treatment is the ability of the amoeba to enclose itself within a shell (a process known as encystment), making it resistant to chemotherapeutic agents. As the cyst wall is partly made of cellulose, thus cellulose degradation offers a potential therapeutic strategy in the effective targeting of trophozoite encased within the cyst walls. Here, we present a comprehensive report on the structure of cellulose and cellulases, as well as known cellulose degradation mechanisms with an eye to target the Acanthamoeba cyst wall. The disruption of the cyst wall will make amoeba (concealed within) susceptible to chemotherapeutic agents, and at the very least inhibition of the excystment process will impede infection recurrence, as we bring these promising drug targets into focus so that they can be explored to their fullest.
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Affiliation(s)
- Sahreena Lakhundi
- Department of Biological and Biomedical Sciences, Aga Khan University, Stadium Road, Karachi, Pakistan.
| | - Ruqaiyyah Siddiqui
- Department of Biological and Biomedical Sciences, Aga Khan University, Stadium Road, Karachi, Pakistan.
| | - Naveed Ahmed Khan
- Department of Biological and Biomedical Sciences, Aga Khan University, Stadium Road, Karachi, Pakistan.
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Stress management in cyst-forming free-living protists: programmed cell death and/or encystment. BIOMED RESEARCH INTERNATIONAL 2015; 2015:437534. [PMID: 25648302 PMCID: PMC4306356 DOI: 10.1155/2015/437534] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Revised: 12/08/2014] [Accepted: 12/24/2014] [Indexed: 11/21/2022]
Abstract
In the face of harsh conditions and given a choice, a cell may (i) undergo programmed cell death, (ii) transform into a cancer cell, or (iii) enclose itself into a cyst form. In metazoans, the available evidence suggests that cellular machinery exists only to execute or avoid programmed cell death, while the ability to form a cyst was either lost or never developed. For cyst-forming free-living protists, here we pose the question whether the ability to encyst was gained at the expense of the programmed cell death or both functions coexist to counter unfavorable environmental conditions with mutually exclusive phenotypes.
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Siddiqui R, Lakhundi S, Khan NA. Status of the effectiveness of contact lens solutions against keratitis-causing pathogens. Cont Lens Anterior Eye 2014; 38:34-8. [PMID: 25280981 DOI: 10.1016/j.clae.2014.09.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Revised: 08/22/2014] [Accepted: 09/09/2014] [Indexed: 11/24/2022]
Abstract
PURPOSE The aim of this study was to assess the antimicrobial effects of marketed contact lens disinfecting solutions. METHODS Using ISO 14729 Stand-Alone Test for disinfecting solutions, bactericidal, fungicidal and amoebicidal assays of eight different contact lens solutions including: ReNu MultiPlus, DuraPlus, Ultimate Plus, OptiFree Express, Kontex Clean, Kontex Normal, Kontex Multisol extra(+), Kontex Soak were performed. The efficacy of contact lens solutions was determined against keratitis-causing microbes, namely: Pseudomonas aeruginosa, Serratia marcescens, Staphylococcus aureus, Methicillin-resistant Staphylococcus aureus, Fusarium solani and Acanthamoeba castellanii. RESULTS The results revealed that ReNu MultiPlus, DuraPlus and OptiFree Express were effective in killing bacterial and fungal pathogens as per manufacturer's minimum recommended disinfection time. Ultimate Plus was effective against F. solani and MRSA but ineffective against P. aeruginosa, S. marcescens and S. aureus. Of concern however, is that none of the locally formulated contact lens disinfecting solutions from Pakistan, i.e., Kontex Clean, Kontex Normal, Kontex Multisol extra(+) and Kontex Soak were effective against any of the keratitis-causing organisms tested. All eight contact lens disinfecting solutions were unable to destroy Acanthamoeba cysts. CONCLUSIONS Because such ineffective contact lens disinfection solutions present a major risk to public health, these findings are of great concern to the health officials and to the manufacturers of the contact lens disinfection solutions and effective solutions are needed, along with emphasis on proper hygiene for contact lens care and special guidelines for developing countries regarding the manufacture and storage of contact lens disinfecting solutions.
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Affiliation(s)
- Ruqaiyyah Siddiqui
- Department of Biological and Biomedical Sciences, Aga Khan University, Karachi, Pakistan
| | - Sahreena Lakhundi
- Department of Biological and Biomedical Sciences, Aga Khan University, Karachi, Pakistan
| | - Naveed Ahmed Khan
- Department of Biological and Biomedical Sciences, Aga Khan University, Karachi, Pakistan.
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