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Khan FA, Irshad R, Tanveer N, Yaqoob S, Razaullah, Ali R, Ali N, Saifullah J, Ali Hasan K, Naz S, Qadir A, Jabeen A, Wang Y. Unleashing the potential of vanillic acid: A new twist on nature's recipe to fight inflammation and circumvent azole-resistant fungal infections. Bioorg Chem 2024; 145:107254. [PMID: 38432152 DOI: 10.1016/j.bioorg.2024.107254] [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: 10/11/2023] [Revised: 02/11/2024] [Accepted: 02/28/2024] [Indexed: 03/05/2024]
Abstract
Vanillic acid (VA) - a naturally occurring phenolic compound in plants - is not only used as a flavoring agent but also a prominent metabolite post tea consumption. VA and its associated compounds are believed to play a significant role in preventing diseases, underscoring the need for a systematic investigation. Herein, we report a 4-step synthesis employing the classical organic reactions, such as Willamson's alkylation, Fischer-Spier reaction, and Steglich esterification, complemented with a protection-deprotection strategy to prepare 46 VA derivatives across the five series (1a-1i, 2a-2i, 3, 3a-3i, 4a-4i, 5a-5i) in high yields. The synthesized compounds were investigated for their antifungal, anti-inflammatory, and toxic effects. Notably, compound 1a demonstrated remarkable ROS inhibition with an IC50 value of 5.1 ± 0.7 µg/mL, which is more than twice as effective as the standard ibuprofen drug. A subset of the synthesized derivatives (2b, 2c, 2e, 3b-3d, 4a-4c, 5a, and 5e) manifested their antifungal effect against drug-resistant Candida strains. Compound 5g, in particular, revealed synergism with the established antifungal drugs amphotericin B (AMB) and fluconazole (FLZ), doubling FLZ's potency against azole resistant Candida albican ATCC 36082. Furthermore, 5g improved the potency of these antifungals against FLZ-sensitive strains, including C. glabrata ATCC 2001 and C. parapsilosis ATCC 22019, as well as various multidrug-resistant (MDR) Candida strains, namely C. albicans ATCC 14053, C. albicans CL1, and C. krusei SH2L OM341600. Additionally, pharmacodynamics of compound 5g was examined using time-kill assay, and a benign safety profile was observed with no hemolytic activity in whole blood, and no cytotoxicity towards the normal BJ human cell line. The synergistic potential of 5g was further investigated through both experimental methods and docking simulations.These findings highlight the therapeutic potential of VA derivatives, particularly in addressing inflammation and circumventing FLZ resistance in Candida albicans.
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Affiliation(s)
- Farooq-Ahmad Khan
- H. E. J. Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi 75270, Pakistan; Third World Center for Science and Technology, International Center for Chemical and Biological Sciences, University of Karachi, Karachi 75270, Pakistan.
| | - Rimsha Irshad
- H. E. J. Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi 75270, Pakistan
| | - Nimra Tanveer
- H. E. J. Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi 75270, Pakistan; Third World Center for Science and Technology, International Center for Chemical and Biological Sciences, University of Karachi, Karachi 75270, Pakistan
| | - Sana Yaqoob
- H. E. J. Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi 75270, Pakistan; Third World Center for Science and Technology, International Center for Chemical and Biological Sciences, University of Karachi, Karachi 75270, Pakistan
| | - Razaullah
- H. E. J. Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi 75270, Pakistan
| | - Raza Ali
- H. E. J. Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi 75270, Pakistan
| | - Nida Ali
- H. E. J. Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi 75270, Pakistan
| | - Jafar Saifullah
- H. E. J. Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi 75270, Pakistan
| | - Khwaja Ali Hasan
- Molecular and Structural Biochemistry Research Laboratory, Department of Biochemistry, University of Karachi, Karachi 75270, Pakistan.
| | - Shahida Naz
- Molecular and Structural Biochemistry Research Laboratory, Department of Biochemistry, University of Karachi, Karachi 75270, Pakistan
| | - Abdul Qadir
- Department of Chemistry, University of Karachi, Karachi 75270, Pakistan
| | - Almas Jabeen
- Dr. Panjwani Center for Molecular Medicine and Drug Research, International Center for Chemical and Biological Sciences, University of Karachi, Karachi 75270, Pakistan
| | - Yan Wang
- H. E. J. Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi 75270, Pakistan; State Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources, School of Chemistry and Pharmaceutical Sciences, Guangxi Normal University, Guilin 541004, China.
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2
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Dominguez JAJ, Luque-Vilca OM, Mallma NES, FLores DDC, Zea CYH, Huayhua LLA, Lizárraga-Gamarra FB, Cáceres CGM, Yauricasa-Tornero SV, Paricanaza-Ticona DC, Cajavilca HLV. Antifungal chemicals promising function in disease prevention, method of action and mechanism. BRAZ J BIOL 2024; 83:e275055. [PMID: 38422253 DOI: 10.1590/1519-6984.275055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Accepted: 09/28/2023] [Indexed: 03/02/2024] Open
Abstract
The increasing use of antimicrobial drugs has been linked to the rise of drug-resistant fungus in recent years. Antimicrobial resistance is being studied from a variety of perspectives due to the important clinical implication of resistance. The processes underlying this resistance, enhanced methods for identifying resistance when it emerges, alternate treatment options for infections caused by resistant organisms, and so on are reviewed, along with strategies to prevent and regulate the formation and spread of resistance. This overview will focus on the action mechanism of antifungals and the resistance mechanisms against them. The link between antibacterial and antifungal resistance is also briefly discussed. Based on their mechanism action, antifungals are divided into three distinct categories: azoles, which target the ergosterol synthesis; 5-fluorocytosine, which targets macromolecular synthesis and polyenes, which interact physiochemically with fungal membrane sterols. Antifungal resistance can arise through a wide variety of ways. Overexpression of the target of the antifungal drug, changes to the drug target, changes to sterol biosynthesis, decreased intercellular concentration of the target enzyme, and other processes. A correlation exists between the mechanisms of resistance to antibacterial and antifungals, despite the fact that the comparison between the two is inevitably constrained by various parameters mentioned in the review. Drug extrusion via membrane pumps has been thoroughly documented in both prokaryotic and eukaryotic cells, and development of new antifungal compounds and strategies has also been well characterized.
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Affiliation(s)
| | | | - N E S Mallma
- Universidad Nacional del Centro del Perú, Huancayo, Perú
| | - D D C FLores
- Universidad Nacional de Huancavelica, Huancavelica, Perú
| | - C Y H Zea
- Universidad Nacional de Juliaca, Juliaca, Perú
| | - L L A Huayhua
- Universidad Nacional de Huancavelica, Huancavelica, Perú
| | | | - C G M Cáceres
- Universidad Nacional de Huancavelica, Huancavelica, Perú
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3
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Sharma V, Madia VN, Tudino V, Nguyen JV, Debnath A, Messore A, Ialongo D, Patacchini E, Palenca I, Basili Franzin S, Seguella L, Esposito G, Petrucci R, Di Matteo P, Bortolami M, Saccoliti F, Di Santo R, Scipione L, Costi R, Podust LM. Miconazole-like Scaffold is a Promising Lead for Naegleria fowleri-Specific CYP51 Inhibitors. J Med Chem 2023; 66:17059-17073. [PMID: 38085955 PMCID: PMC10758121 DOI: 10.1021/acs.jmedchem.3c01898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Revised: 11/17/2023] [Accepted: 11/22/2023] [Indexed: 12/29/2023]
Abstract
Developing drugs for brain infection by Naegleria fowleri is an unmet medical need. We used a combination of cheminformatics, target-, and phenotypic-based drug discovery methods to identify inhibitors that target an essential N. fowleri enzyme, sterol 14-demethylase (NfCYP51). A total of 124 compounds preselected in silico were tested against N. fowleri. Nine primary hits with EC50 ≤ 10 μM were phenotypically identified. Cocrystallization with NfCYP51 focused attention on one primary hit, miconazole-like compound 2a. The S-enantiomer of 2a produced a 1.74 Å cocrystal structure. A set of analogues was then synthesized and evaluated to confirm the superiority of the S-configuration over the R-configuration and the advantage of an ether linkage over an ester linkage. The two compounds, S-8b and S-9b, had an improved EC50 and KD compared to 2a. Importantly, both were readily taken up into the brain. The brain-to-plasma distribution coefficient of S-9b was 1.02 ± 0.12, suggesting further evaluation as a lead for primary amoebic meningoencephalitis.
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Affiliation(s)
- Vandna Sharma
- Skaggs
School of Pharmacy and Pharmaceutical Sciences, Center for Discovery
and Innovation in Parasitic Diseases, University
of California San Diego, La Jolla, California 92093, United States
| | - Valentina Noemi Madia
- Dipartimento
di Chimica e Tecnologie del Farmaco, Istituto Pasteur-Fondazione Cenci
Bolognetti, “Sapienza” Università
di Roma, p.le Aldo Moro 5, Rome I-00185, Italy
| | - Valeria Tudino
- Dipartimento
di Biotecnologie, Università degli
Studi di Siena, Chimica e Farmacia via Aldo Moro 2, Siena 53100, Italy
| | - Jennifer V. Nguyen
- Skaggs
School of Pharmacy and Pharmaceutical Sciences, Center for Discovery
and Innovation in Parasitic Diseases, University
of California San Diego, La Jolla, California 92093, United States
| | - Anjan Debnath
- Skaggs
School of Pharmacy and Pharmaceutical Sciences, Center for Discovery
and Innovation in Parasitic Diseases, University
of California San Diego, La Jolla, California 92093, United States
| | - Antonella Messore
- Dipartimento
di Chimica e Tecnologie del Farmaco, Istituto Pasteur-Fondazione Cenci
Bolognetti, “Sapienza” Università
di Roma, p.le Aldo Moro 5, Rome I-00185, Italy
| | - Davide Ialongo
- Dipartimento
di Chimica e Tecnologie del Farmaco, Istituto Pasteur-Fondazione Cenci
Bolognetti, “Sapienza” Università
di Roma, p.le Aldo Moro 5, Rome I-00185, Italy
| | - Elisa Patacchini
- Dipartimento
di Chimica e Tecnologie del Farmaco, Istituto Pasteur-Fondazione Cenci
Bolognetti, “Sapienza” Università
di Roma, p.le Aldo Moro 5, Rome I-00185, Italy
| | - Irene Palenca
- Department
of Physiology and Pharmacology “V. Erspamer”, “Sapienza″ Università di Roma, p.le Aldo Moro 5, Rome I-00185, Italy
| | - Silvia Basili Franzin
- Department
of Physiology and Pharmacology “V. Erspamer”, “Sapienza″ Università di Roma, p.le Aldo Moro 5, Rome I-00185, Italy
| | - Luisa Seguella
- Department
of Physiology and Pharmacology “V. Erspamer”, “Sapienza″ Università di Roma, p.le Aldo Moro 5, Rome I-00185, Italy
| | - Giuseppe Esposito
- Department
of Physiology and Pharmacology “V. Erspamer”, “Sapienza″ Università di Roma, p.le Aldo Moro 5, Rome I-00185, Italy
| | - Rita Petrucci
- Dipartimento
di Scienze di Base e Applicate per l’Ingegneria, “Sapienza” Università di Roma, Via Castro Laurenziano 7, Rome 00161, Italy
| | - Paola Di Matteo
- Dipartimento
di Scienze di Base e Applicate per l’Ingegneria, “Sapienza” Università di Roma, Via Castro Laurenziano 7, Rome 00161, Italy
| | - Martina Bortolami
- Dipartimento
di Scienze di Base e Applicate per l’Ingegneria, “Sapienza” Università di Roma, Via Castro Laurenziano 7, Rome 00161, Italy
| | - Francesco Saccoliti
- D3 PharmaChemistry, Italian
Institute of Technology, Via Morego 30, Genova 16163, Italy
| | - Roberto Di Santo
- Dipartimento
di Chimica e Tecnologie del Farmaco, Istituto Pasteur-Fondazione Cenci
Bolognetti, “Sapienza” Università
di Roma, p.le Aldo Moro 5, Rome I-00185, Italy
| | - Luigi Scipione
- Dipartimento
di Chimica e Tecnologie del Farmaco, Istituto Pasteur-Fondazione Cenci
Bolognetti, “Sapienza” Università
di Roma, p.le Aldo Moro 5, Rome I-00185, Italy
| | - Roberta Costi
- Dipartimento
di Chimica e Tecnologie del Farmaco, Istituto Pasteur-Fondazione Cenci
Bolognetti, “Sapienza” Università
di Roma, p.le Aldo Moro 5, Rome I-00185, Italy
| | - Larissa M. Podust
- Skaggs
School of Pharmacy and Pharmaceutical Sciences, Center for Discovery
and Innovation in Parasitic Diseases, University
of California San Diego, La Jolla, California 92093, United States
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4
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Yuan A, Fong H, Nguyen JV, Nguyen S, Norman P, Cullum R, Fenical W, Debnath A. High-Throughput Screen of Microbial Metabolites Identifies F 1F O ATP Synthase Inhibitors as New Leads for Naegleria fowleri Infection. ACS Infect Dis 2023; 9:2622-2631. [PMID: 37943251 DOI: 10.1021/acsinfecdis.3c00437] [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] [Indexed: 11/10/2023]
Abstract
Primary amebic meningoencephalitis (PAM), a brain infection caused by a free-living ameba Naegleria fowleri, leads to an extensive inflammation of the brain and death within 1-18 (median 5) days after symptoms begin. Although natural products have played a significant role in the development of drugs for over a century, research focusing on identifying new natural product-based anti-N. fowleri agents is limited. We undertook a large-scale ATP bioluminescence-based screen of about 10,000 unique marine microbial metabolite mixtures against the trophozoites of N. fowleri. Our screen identified about 100 test materials with >90% inhibition at 50 μg/mL and a dose-response study found 20 of these active test materials exhibiting an EC50 ranging from 0.2 to 2 μg/mL. Examination of four of these potent metabolite mixtures, derived from our actinomycete strains CNT671, CNT756, and CNH301, resulted in the isolation of a pure metabolite identified as oligomycin D. Oligomycin D exhibited nanomolar potency on multiple genotypes of N. fowleri, and it was five- or 850-times more potent than the recommended drugs amphotericin B or miltefosine. Oligomycin D is fast-acting and reached its EC50 in 10 h, and it was also able to inhibit the invasiveness of N. fowleri significantly when tested on a matrigel invasion assay. Since oligomycin is known to manifest inhibitory activity against F1FO ATP synthase, we tested different F1FO ATP synthase inhibitors and identified a natural peptide leucinostatin as a fast-acting amebicidal compound with nanomolar potency on multiple strains.
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Affiliation(s)
- Alice Yuan
- Center for Discovery and Innovation in Parasitic Diseases, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, California 92093, United States
| | - Hayley Fong
- Center for Discovery and Innovation in Parasitic Diseases, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, California 92093, United States
| | - Jennifer V Nguyen
- Center for Discovery and Innovation in Parasitic Diseases, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, California 92093, United States
| | - Sophia Nguyen
- Center for Discovery and Innovation in Parasitic Diseases, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, California 92093, United States
| | - Payton Norman
- Center for Discovery and Innovation in Parasitic Diseases, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, California 92093, United States
| | - Reiko Cullum
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San Diego, La Jolla, California 92093, United States
| | - William Fenical
- Center for Discovery and Innovation in Parasitic Diseases, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, California 92093, United States
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San Diego, La Jolla, California 92093, United States
| | - Anjan Debnath
- Center for Discovery and Innovation in Parasitic Diseases, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, California 92093, United States
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5
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Akbar N, Siddiqui R, El-Gamal MI, Zaraei SO, Alawfi BS, Khan NA. The anti-amoebic potential of carboxamide derivatives containing sulfonyl or sulfamoyl moieties against brain-eating Naegleria fowleri. Parasitol Res 2023; 122:2539-2548. [PMID: 37665414 DOI: 10.1007/s00436-023-07953-w] [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: 05/22/2023] [Accepted: 08/18/2023] [Indexed: 09/05/2023]
Abstract
Naegleria fowleri is a free-living thermophilic flagellate amoeba that causes a rare but life-threatening infection called primary amoebic meningoencephalitis (PAM), with a very high fatality rate. Herein, the anti-amoebic potential of carboxamide derivatives possessing sulfonyl or sulfamoyl moiety was assessed against pathogenic N. fowleri using amoebicidal, cytotoxicity and cytopathogenicity assays. The results from amoebicidal experiments showed that derivatives dramatically reduced N. fowleri viability. Selected derivatives demonstrated IC50 values at lower concentrations; 1j showed IC50 at 24.65 μM, while 1k inhibited 50% amoebae growth at 23.31 μM. Compounds with significant amoebicidal effects demonstrated limited cytotoxicity against human cerebral microvascular endothelial cells. Finally, some derivatives mitigated N. fowleri-instigated host cell death. Ultimately, this study demonstrated that 1j and 1k exhibited potent anti-amoebic activity and ought to be looked at in future studies for the development of therapeutic anti-amoebic pharmaceuticals. Further investigation is required to determine the clinical relevance of our findings.
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Affiliation(s)
- Noor Akbar
- Research Institute of Medical and Health Sciences, University of Sharjah, University City, Sharjah, 27272, United Arab Emirates
- Department of Clinical Sciences, College of Medicine, University of Sharjah, University City, Sharjah, 27272, United Arab Emirates
| | - Ruqaiyyah Siddiqui
- College of Arts and Sciences, American University of Sharjah, University City, Sharjah, 26666, United Arab Emirates
- Microbiota Research Center, Istinye University, 34010, Istanbul, Turkey
| | - Mohammed I El-Gamal
- Research Institute of Medical and Health Sciences, University of Sharjah, University City, Sharjah, 27272, United Arab Emirates.
- Department of Medicinal Chemistry, College of Pharmacy, University of Sharjah, Sharjah, 27272, United Arab Emirates.
- Department of Medicinal Chemistry, Faculty of Pharmacy, Mansoura University, Mansoura, 35516, Egypt.
| | - Seyed-Omar Zaraei
- Research Institute of Medical and Health Sciences, University of Sharjah, University City, Sharjah, 27272, United Arab Emirates
| | - Bader S Alawfi
- Department of Medical Laboratories Technology, College of Applied Medical Sciences, Taibah University, Madinah, 42353, Saudi Arabia
| | - Naveed Ahmed Khan
- Microbiota Research Center, Istinye University, 34010, Istanbul, Turkey.
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6
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Gan Q, Cui X, Zhang L, Zhou W, Lu Y. Control Phytophagous Nematodes By Engineering Phytosterol Dealkylation Caenorhabditis elegans as a Model. Mol Biotechnol 2023:10.1007/s12033-023-00869-x. [PMID: 37843756 DOI: 10.1007/s12033-023-00869-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Accepted: 08/25/2023] [Indexed: 10/17/2023]
Abstract
Plant-parasitic nematodes ingest and convert host phytosterols via dealkylation to cholesterol for both structural and hormonal requirements. The insect 24-dehydrocholesterol reductase (DHCR24) was shown in vitro as a committed enzyme in the dealkylation via chemical blocking. However, an increased brood size and ovulation rate, instead compromised development, were observed in the engineered nematode Caenorhabditis elegans where the DHCR24 gene was knocked down, indicating the relationship between DHCR24 and dealkylation and their function in nematodes remains illusive. In this study, a defect in C. elegans DHCR24 causes impaired growth of the nematode with sitosterol (a major component of phytosterols) as a sole sterol source. Plant sterols with rationally designed structure (null substrates for dealkylation) can't be converted to cholesterol in wild-type worms, and their development was completely halted. This study underpins the essential function of DHCR24 in nematodes and would be beneficial for the development of novel nematocidal strategies.
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Affiliation(s)
- Qinhua Gan
- State Key Laboratory of Marine Resource Utilization in South China Sea, School of Marine Biology and Fisheries, Hainan University, Hainan Province, 570228, Hainan, China
- School of Tropical Agriculture and Forestry, Hainan University, Haikou Province, 570228, Hainan, China
| | - Xinyu Cui
- State Key Laboratory of Marine Resource Utilization in South China Sea, School of Marine Biology and Fisheries, Hainan University, Hainan Province, 570228, Hainan, China
| | - Lin Zhang
- Shandong Rongchen Pharmaceuticals Inc, Qingdao, 266061, China
| | - Wenxu Zhou
- State Key Laboratory of Marine Resource Utilization in South China Sea, School of Marine Biology and Fisheries, Hainan University, Hainan Province, 570228, Hainan, China.
| | - Yandu Lu
- State Key Laboratory of Marine Resource Utilization in South China Sea, School of Marine Biology and Fisheries, Hainan University, Hainan Province, 570228, Hainan, China.
- Key Laboratory of Tropical Hydrobiotechnology of Hainan Province, Hainan University, Haikou, 570228, China.
- Haikou Innovation Center for Research and Utilization of Algal Bioresources, Hainan University, Haikou, 570228, China.
- Hainan Engineering and Research Center of Marine Bioactives & Bioproducts, Hainan University, Haikou, 570228, China.
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7
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Ferrins L, Buskes MJ, Kapteyn MM, Engels HN, Enos SE, Lu C, Klug DM, Singh B, Quotadamo A, Bachovchin K, Tear WF, Spaulding AE, Forbes KC, Bag S, Rivers M, LeBlanc C, Burchfield E, Armand JR, Diaz-Gonzalez R, Ceballos-Perez G, García-Hernández R, Pérez-Moreno G, Bosch-Navarrete C, Gómez-Liñán C, Ruiz-Pérez LM, Gamarro F, González-Pacanowska D, Navarro M, Mensa-Wilmot K, Pollastri MP, Kyle DE, Rice CA. Identification of novel anti-amoebic pharmacophores from kinase inhibitor chemotypes. Front Microbiol 2023; 14:1149145. [PMID: 37234530 PMCID: PMC10206040 DOI: 10.3389/fmicb.2023.1149145] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2023] [Accepted: 03/29/2023] [Indexed: 05/28/2023] Open
Abstract
Acanthamoeba species, Naegleria fowleri, and Balamuthia mandrillaris are opportunistic pathogens that cause a range of brain, skin, eye, and disseminated diseases in humans and animals. These pathogenic free-living amoebae (pFLA) are commonly misdiagnosed and have sub-optimal treatment regimens which contribute to the extremely high mortality rates (>90%) when they infect the central nervous system. To address the unmet medical need for effective therapeutics, we screened kinase inhibitor chemotypes against three pFLA using phenotypic drug assays involving CellTiter-Glo 2.0. Herein, we report the activity of the compounds against the trophozoite stage of each of the three amoebae, ranging from nanomolar to low micromolar potency. The most potent compounds that were identified from this screening effort were: 2d (A. castellanii EC50: 0.92 ± 0.3 μM; and N. fowleri EC50: 0.43 ± 0.13 μM), 1c and 2b (N. fowleri EC50s: <0.63 μM, and 0.3 ± 0.21 μM), and 4b and 7b (B. mandrillaris EC50s: 1.0 ± 0.12 μM, and 1.4 ± 0.17 μM, respectively). With several of these pharmacophores already possessing blood-brain barrier (BBB) permeability properties, or are predicted to penetrate the BBB, these hits present novel starting points for optimization as future treatments for pFLA-caused diseases.
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Affiliation(s)
- Lori Ferrins
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA, United States
| | - Melissa J. Buskes
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA, United States
| | - Madison M. Kapteyn
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA, United States
| | - Hannah N. Engels
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA, United States
| | - Suzanne E. Enos
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA, United States
- Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, Athens, GA, United States
| | - Chenyang Lu
- Department of Comparative Pathobiology, College of Veterinary Medicine, Purdue University, West Lafayette, IN, United States
| | - Dana M. Klug
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA, United States
| | - Baljinder Singh
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA, United States
| | - Antonio Quotadamo
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA, United States
- Clinical and Experimental Medicine PhD Program, University of Modena and Reggio Emilia, Modena, Italy
| | - Kelly Bachovchin
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA, United States
| | - Westley F. Tear
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA, United States
| | - Andrew E. Spaulding
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA, United States
| | - Katherine C. Forbes
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA, United States
| | - Seema Bag
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA, United States
| | - Mitch Rivers
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA, United States
| | - Catherine LeBlanc
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA, United States
| | - Erin Burchfield
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA, United States
| | - Jeremy R. Armand
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA, United States
| | - Rosario Diaz-Gonzalez
- Instituto de Parasitología y Biomedicina “López-Neyra” Consejo Superior de Investigaciones Científicas (CSIC), Granada, Spain
| | - Gloria Ceballos-Perez
- Instituto de Parasitología y Biomedicina “López-Neyra” Consejo Superior de Investigaciones Científicas (CSIC), Granada, Spain
| | - Raquel García-Hernández
- Instituto de Parasitología y Biomedicina “López-Neyra” Consejo Superior de Investigaciones Científicas (CSIC), Granada, Spain
| | - Guiomar Pérez-Moreno
- Instituto de Parasitología y Biomedicina “López-Neyra” Consejo Superior de Investigaciones Científicas (CSIC), Granada, Spain
| | - Cristina Bosch-Navarrete
- Instituto de Parasitología y Biomedicina “López-Neyra” Consejo Superior de Investigaciones Científicas (CSIC), Granada, Spain
| | - Claudia Gómez-Liñán
- Instituto de Parasitología y Biomedicina “López-Neyra” Consejo Superior de Investigaciones Científicas (CSIC), Granada, Spain
| | - Luis Miguel Ruiz-Pérez
- Instituto de Parasitología y Biomedicina “López-Neyra” Consejo Superior de Investigaciones Científicas (CSIC), Granada, Spain
| | - Francisco Gamarro
- Instituto de Parasitología y Biomedicina “López-Neyra” Consejo Superior de Investigaciones Científicas (CSIC), Granada, Spain
| | - Dolores González-Pacanowska
- Instituto de Parasitología y Biomedicina “López-Neyra” Consejo Superior de Investigaciones Científicas (CSIC), Granada, Spain
| | - Miguel Navarro
- Instituto de Parasitología y Biomedicina “López-Neyra” Consejo Superior de Investigaciones Científicas (CSIC), Granada, Spain
| | - Kojo Mensa-Wilmot
- Department of Molecular and Cellular Biology, Kennesaw State University, Kennesaw, GA, United States
| | - Michael P. Pollastri
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA, United States
| | - Dennis E. Kyle
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA, United States
| | - Christopher A. Rice
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA, United States
- Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, Athens, GA, United States
- Department of Comparative Pathobiology, College of Veterinary Medicine, Purdue University, West Lafayette, IN, United States
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8
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Dutra JAP, Maximino SC, Gonçalves RDCR, Morais PAB, de Lima Silva WC, Rodrigues RP, Neto ÁC, Júnior VL, de Souza Borges W, Kitagawa RR. Anti-Candida, docking studies, and in vitro metabolism-mediated cytotoxicity evaluation of Eugenol derivatives. Chem Biol Drug Des 2023; 101:350-363. [PMID: 36053023 DOI: 10.1111/cbdd.14131] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 08/02/2022] [Accepted: 08/14/2022] [Indexed: 01/14/2023]
Abstract
The high morbidity and mortality rates of Candida infections, especially among immunocompromised patients, are related to the increased resistance rate of these species and the limited therapeutic arsenal. In this context, we evaluated the anti-Candida potential and the cytotoxic profile of eugenol derivatives. Anti-Candida activity was evaluated on C. albicans and C. parapsilosis strains by minimum inhibitory concentration (MIC), scanning electron microscopy (SEM), and molecular docking calculations at the site of the enzyme lanosterol-14-α-demethylase active site, responsible for ergosterol formation. The cytotoxic profile was evaluated in HepG2 cells, in the presence and absence of the metabolizing system (S9 system). The results indicated compounds 1b and 1d as the most active ones. The compounds have anti-Candida activity against both strains with MIC ranging from 50 to 100 μg ml-1 . SEM analyses of 1b and 1d indicated changes in the envelope architecture of both C. albicans and C. parapsilosis like the ones of eugenol and fluconazole, respectively. Docking results of the evaluated compounds indicated a similar binding pattern of fluconazole and posaconazole at the lanosterol-14-α-demethylase binding site. In the presence of the S9 system, compound 1b showed the same cytotoxicity profile as fluconazole (1.08 times) and compound 1d had 1.23 times increase in cytotoxicity. Eugenol and other evaluated compounds showed a significant increase in cytotoxicity. Our results suggest compound 1b as a promising starting point candidate to be used in the design of new anti-Candida agent prototypes.
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Affiliation(s)
- Jessyca Aparecida Paes Dutra
- Graduate Program of Pharmaceutical Sciences, Health Sciences Center, Federal University of Espírito Santo, Bonfim, Brazil
| | - Sarah Canal Maximino
- Graduate Program of Pharmaceutical Sciences, Health Sciences Center, Federal University of Espírito Santo, Bonfim, Brazil
| | | | - Pedro Alves Bezerra Morais
- Department of Chemistry and Physics, Exact, Natural and Health Sciences Center, Federal University of Espírito Santo, Guararema, Brazil
| | | | - Ricardo Pereira Rodrigues
- Graduate Program of Pharmaceutical Sciences, Health Sciences Center, Federal University of Espírito Santo, Bonfim, Brazil
| | - Álvaro Cunha Neto
- Department of Chemistry, Exact Sciences Center, Federal University of Espírito Santo, Goiabeiras, Brazil
| | - Valdemar Lacerda Júnior
- Department of Chemistry, Exact Sciences Center, Federal University of Espírito Santo, Goiabeiras, Brazil
| | - Warley de Souza Borges
- Department of Chemistry, Exact Sciences Center, Federal University of Espírito Santo, Goiabeiras, Brazil
| | - Rodrigo Rezende Kitagawa
- Graduate Program of Pharmaceutical Sciences, Health Sciences Center, Federal University of Espírito Santo, Bonfim, Brazil
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9
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Geesi MH, Riadi Y, Kaiba A, Ibnouf EO, Anouar EH, Dehbi O, Lazar S, Guionneau P. Synthesis, antimicrobial evaluation, crystal structure, Hirschfeld surface analysis and docking studies of 4-[2-(1-methyl-1H-imidazol-2-ylsulfanyl)-acetylamino]-benzenesulfonic acid. J Mol Struct 2022. [DOI: 10.1016/j.molstruc.2022.133425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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10
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Abraham J, Chauhan N, Ray S. Virtual Screening of Alkaloid and Terpenoid Inhibitors of SMT Expressed in Naegleria sp. Molecules 2022; 27:molecules27175727. [PMID: 36080504 PMCID: PMC9457665 DOI: 10.3390/molecules27175727] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 08/29/2022] [Accepted: 09/02/2022] [Indexed: 11/16/2022] Open
Abstract
The pathogenic form of thermophilic Naegleria sp. i.e., Naegleria fowleri, also known as brain eating amoeba, causes primary amoebic encephalitis (PAM) with a >97% fatality rate. To date, there are no specific drugs identified to treat this disease specifically. The present antimicrobial combinatorial chemotherapy is hard on many patients, especially children. Interestingly, Naegleria fowleri has complex lipid biosynthesis pathways like other protists and also has a strong preference to utilize absorbed host lipids for generating energy. The ergosterol biosynthesis pathway provides a unique drug target opportunity, as some of the key enzymes involved in this pathway are absent in humans. Sterol 24-C Methyltransferase (SMT) is one such enzyme that is not found in humans. To select novel inhibitors for this enzyme, alkaloids and terpenoids inhibitors were screened and tested against two isozymes of SMT identified in N. gruberi (non-pathogenic) as well as its homolog found in yeast, i.e., ERG6. Five natural product derived inhibitors i.e., Cyclopamine, Chelerythrine, Berberine, Tanshinone 2A, and Catharanthine have been identified as potential drug candidates based on multiple criteria including binding affinity, ADME scores, absorption, and, most importantly, its ability to cross the blood brain barrier. This study provides multiple leads for future drug exploration against Naegleria fowleri.
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Affiliation(s)
- Jason Abraham
- Department of Natural Sciences, Bowie State University, 14000 Jericho Park Rd., Bowie, MD 20715, USA
| | - Neha Chauhan
- Department of Chemistry & Biochemistry, University of Texas El Paso, 500 W. University Ave., El Paso, TX 79968, USA
| | - Supriyo Ray
- Department of Natural Sciences, Bowie State University, 14000 Jericho Park Rd., Bowie, MD 20715, USA
- Correspondence:
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11
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Ahmed U, Ho KY, Simon SE, Saad SM, Ong SK, Anwar A, Tan KO, Sridewi N, Khan KM, Khan NA, Anwar A. Potential anti-acanthamoebic effects through inhibition of CYP51 by novel quinazolinones. Acta Trop 2022; 231:106440. [PMID: 35378058 DOI: 10.1016/j.actatropica.2022.106440] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 03/27/2022] [Accepted: 03/30/2022] [Indexed: 12/01/2022]
Abstract
Acanthamoeba spp. are free living amoebae which can give rise to Acanthamoeba keratitis and granulomatous amoebic encephalitis. The surface of Acanthamoeba contains ergosterol which is an important target for drug development against eukaryotic microorganisms. A library of ten functionally diverse quinazolinone derivatives (Q1-Q10) were synthesised to assess their activity against Acanthamoeba castellanii T4. The in-vitro effectiveness of these quinazolinones were investigated against Acanthamoeba castellanii by amoebicidal, excystation, host cell cytopathogenicity, and NADPH-cytochrome c reductase assays. Furthermore, wound healing capability was assessed at different time durations. Maximum inhibition at 50 μg/mL was recorded for compounds Q5, Q6 and Q8, while the compound Q3 did not exhibit amoebicidal effects at tested concentrations. Moreover, LDH assay was conducted to assess the cytotoxicity of quinazolinones against HaCaT cell line. The results of wound healing assay revealed that all compounds are not cytotoxic and are likely to promote wound healing at 10 μg/mL. The excystation assays revealed that these compounds significantly inhibit the morphological transformation of A. castellanii. Compound Q3, Q7 and Q8 elevated the level of NADPH-cytochrome c reductase up to five folds. Sterol 14alpha-demethylase (CYP51) a reference enzyme in ergosterol pathway was used as a potential target for anti-amoebic drugs. In this study using i-Tasser, the protein structure of Acanthamoeba castellanii (AcCYP51) was developed in comparison with Naegleria fowleri protein (NfCYP51) structure. The sequence alignment of both proteins has shown 42.72% identity. Compounds Q1-Q10 were then molecularly docked with the predicted AcCYP51. Out of ten quinazolinones, three compounds (Q3, Q7 and Q8) showed good binding activity within 3 Å of TYR 114. The in-silico study confirmed that these compounds are the inhibitor of CYP51 target site. This report presents several potential lead compounds belonging to quinazolinone derivatives for drug discovery against Acanthamoeba infections.
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Affiliation(s)
- Usman Ahmed
- Department of Biological Sciences, School of Medical and Life Sciences, Sunway University, Subang Jaya, Selangor, Malaysia
| | - Keat-Yie Ho
- Department of Biological Sciences, School of Medical and Life Sciences, Sunway University, Subang Jaya, Selangor, Malaysia
| | - Samson Eugin Simon
- Department of Biological Sciences, School of Medical and Life Sciences, Sunway University, Subang Jaya, Selangor, Malaysia
| | | | - Seng-Kai Ong
- Department of Biological Sciences, School of Medical and Life Sciences, Sunway University, Subang Jaya, Selangor, Malaysia
| | - Areeba Anwar
- Faculty of Defence Science and Technology, National Defence University of Malaysia, Kuala Lumpur, Malaysia
| | - Kuan Onn Tan
- Department of Biological Sciences, School of Medical and Life Sciences, Sunway University, Subang Jaya, Selangor, Malaysia
| | - Nanthini Sridewi
- Faculty of Defence Science and Technology, National Defence University of Malaysia, Kuala Lumpur, Malaysia
| | - Khalid Mohammed Khan
- H. E. J. Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi, Pakistan; Department of Clinical Pharmacy, Institute for Research and Medical Consultations (IRMC), Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia
| | - Naveed Ahmed Khan
- Department of Clinical Sciences, College of Medicine, University of Sharjah, Sharjah, University City, United Arab Emirates
| | - Ayaz Anwar
- Department of Biological Sciences, School of Medical and Life Sciences, Sunway University, Subang Jaya, Selangor, Malaysia.
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12
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Nienhaus K, Sharma V, Nienhaus GU, Podust LM. Homodimerization Counteracts the Detrimental Effect of Nitrogenous Heme Ligands on the Enzymatic Activity of Acanthamoeba castellanii CYP51. Biochemistry 2022; 61:1363-1377. [PMID: 35730528 DOI: 10.1021/acs.biochem.2c00198] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Acanthamoeba castellanii is a free-living amoeba that can cause severe eye and brain infections in humans. At present, there is no uniformly effective treatment for any of these infections. However, sterol 14α-demethylases (CYP51s), heme-containing cytochrome P450 enzymes, are known to be validated drug targets in pathogenic fungi and protozoa. The catalytically active P450 form of CYP51 from A. castellanii (AcCYP51) is stabilized against conversion to the inactive P420 form by dimerization. In contrast, Naegleria fowleri CYP51 (NfCYP51) is monomeric in its active P450 and inactive P420 forms. For these two CYP51 enzymes, we have investigated the interplay between the enzyme activity and oligomerization state using steady-state and time-resolved UV-visible absorption spectroscopy. In both enzymes, the P450 → P420 transition is favored under reducing conditions. The transition is accelerated at higher pH, which excludes a protonated thiol as the proximal ligand in P420. Displacement of the proximal thiolate ligand is also promoted by adding exogenous nitrogenous ligands (N-ligands) such as imidazole, isavuconazole, and clotrimazole that bind at the opposite, distal heme side. In AcCYP51, the P450 → P420 transition is faster in the monomer than in the dimer, indicating that the dimeric assembly is critical for stabilizing thiolate coordination to the heme and thus for sustaining AcCYP51 activity. The spectroscopic experiments were complemented with size-exclusion chromatography and X-ray crystallography studies. Collectively, our results indicate that effective inactivation of the AcCYP51 function by azole drugs is due to synergistic interference with AcCYP51 dimerization and promoting irreversible displacement of the proximal heme-thiolate ligand.
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Affiliation(s)
- Karin Nienhaus
- Institute of Applied Physics, Karlsruhe Institute of Technology (KIT), D-76049 Karlsruhe, Germany
| | - Vandna Sharma
- Skaggs School of Pharmacy and Pharmaceutical Sciences, Center for Discovery and Innovation in Parasitic Diseases, University of California San Diego, La Jolla, California 92093, United States
| | - Gerd Ulrich Nienhaus
- Institute of Applied Physics, Karlsruhe Institute of Technology (KIT), D-76049 Karlsruhe, Germany.,Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany.,Institute of Biological and Chemical Systems, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany.,Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Larissa M Podust
- Skaggs School of Pharmacy and Pharmaceutical Sciences, Center for Discovery and Innovation in Parasitic Diseases, University of California San Diego, La Jolla, California 92093, United States
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13
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Malinga NA, Nzuza N, Padayachee T, Syed PR, Karpoormath R, Gront D, Nelson DR, Syed K. An Unprecedented Number of Cytochrome P450s Are Involved in Secondary Metabolism in Salinispora Species. Microorganisms 2022; 10:microorganisms10050871. [PMID: 35630316 PMCID: PMC9143469 DOI: 10.3390/microorganisms10050871] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 04/15/2022] [Accepted: 04/19/2022] [Indexed: 01/04/2023] Open
Abstract
Cytochrome P450 monooxygenases (CYPs/P450s) are heme thiolate proteins present in species across the biological kingdoms. By virtue of their broad substrate promiscuity and regio- and stereo-selectivity, these enzymes enhance or attribute diversity to secondary metabolites. Actinomycetes species are well-known producers of secondary metabolites, especially Salinispora species. Despite the importance of P450s, a comprehensive comparative analysis of P450s and their role in secondary metabolism in Salinispora species is not reported. We therefore analyzed P450s in 126 strains from three different species Salinispora arenicola, S. pacifica, and S. tropica. The study revealed the presence of 2643 P450s that can be grouped into 45 families and 103 subfamilies. CYP107 and CYP125 families are conserved, and CYP105 and CYP107 families are bloomed (a P450 family with many members) across Salinispora species. Analysis of P450s that are part of secondary metabolite biosynthetic gene clusters (smBGCs) revealed Salinispora species have an unprecedented number of P450s (1236 P450s-47%) part of smBGCs compared to other bacterial species belonging to the genera Streptomyces (23%) and Mycobacterium (11%), phyla Cyanobacteria (8%) and Firmicutes (18%) and the classes Alphaproteobacteria (2%) and Gammaproteobacteria (18%). A peculiar characteristic of up to six P450s in smBGCs was observed in Salinispora species. Future characterization Salinispora species P450s and their smBGCs have the potential for discovering novel secondary metabolites.
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Affiliation(s)
- Nsikelelo Allison Malinga
- Department of Biochemistry and Microbiology, Faculty of Science and Agriculture, University of Zululand, KwaDlangezwa 3886, South Africa; (N.A.M.); (N.N.); (T.P.)
| | - Nomfundo Nzuza
- Department of Biochemistry and Microbiology, Faculty of Science and Agriculture, University of Zululand, KwaDlangezwa 3886, South Africa; (N.A.M.); (N.N.); (T.P.)
| | - Tiara Padayachee
- Department of Biochemistry and Microbiology, Faculty of Science and Agriculture, University of Zululand, KwaDlangezwa 3886, South Africa; (N.A.M.); (N.N.); (T.P.)
| | - Puleng Rosinah Syed
- Department of Pharmaceutical Chemistry, College of Health Sciences, University of KwaZulu-Natal, Durban 4000, South Africa; (P.R.S.); (R.K.)
| | - Rajshekhar Karpoormath
- Department of Pharmaceutical Chemistry, College of Health Sciences, University of KwaZulu-Natal, Durban 4000, South Africa; (P.R.S.); (R.K.)
| | - Dominik Gront
- Faculty of Chemistry, Biological and Chemical Research Centre, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland;
| | - David R. Nelson
- Department of Microbiology, Immunology and Biochemistry, University of Tennessee Health Science Center, Memphis, TN 38163, USA
- Correspondence: (D.R.N.); (K.S.); Tel.: +19-014-488-303 (D.R.N.); +27-035-902-6857 (K.S.)
| | - Khajamohiddin Syed
- Department of Biochemistry and Microbiology, Faculty of Science and Agriculture, University of Zululand, KwaDlangezwa 3886, South Africa; (N.A.M.); (N.N.); (T.P.)
- Correspondence: (D.R.N.); (K.S.); Tel.: +19-014-488-303 (D.R.N.); +27-035-902-6857 (K.S.)
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14
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Differential Growth Rates and In Vitro Drug Susceptibility to Currently Used Drugs for Multiple Isolates of Naegleria fowleri. Microbiol Spectr 2022; 10:e0189921. [PMID: 35138140 PMCID: PMC8826828 DOI: 10.1128/spectrum.01899-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
The free-living amoeba Naegleria fowleri, which typically dwells within warm, freshwater environments, can opportunistically cause primary amoebic meningoencephalitis (PAM), a disease with a mortality rate of >97%. The lack of positive treatment outcomes for PAM has prompted the discovery and development of more effective therapeutics, yet most studies utilize only one or two clinical isolates. The inability to assess possible heterogenic responses to drugs among isolates from various geographical regions hinders progress in the discovery of more effective drugs. Here, we conducted drug efficacy and growth rate determinations for 11 different clinical isolates by applying a previously developed CellTiter-Glo 2.0 screening technique and flow cytometry. We found significant differences in the susceptibilities of these isolates to 7 of 8 drugs tested, all of which make up the cocktail that is recommended to physicians by the U.S. Centers for Disease Control and Prevention. We also discovered significant variances in growth rates among isolates, which draws attention to the differences among the amoeba isolates collected from different patients. Our results demonstrate the need for additional clinical isolates of various genotypes in drug assays and highlight the necessity for more targeted therapeutics with universal efficacy across N. fowleri isolates. Our data establish a needed baseline for drug susceptibility among clinical isolates and provide a segue for future combination therapy studies as well as research related to phenotypic or genetic differences that could shed light on mechanisms of action or predispositions to specific drugs. IMPORTANCENaegleria fowleri, also known as the brain-eating amoeba, is ubiquitous in warm freshwater and is an opportunistic pathogen that causes primary amoebic meningoencephalitis. Although few cases are described each year, the disease has a case fatality rate of >97%. In most laboratory studies of this organism, only one or two well-adapted lab strains are used; therefore, there is a lack of data to discern if there are major differences in potency of currently used drugs for multiple strains and genotypes of the amoeba. In this study, we found significant differences in the susceptibilities of 11 N. fowleri isolates to 7 of the 8 drugs currently used to treat the disease. The data from this study provide a baseline of drug susceptibility among clinical isolates and suggest that new drugs should be tested on a larger number of isolates in the future.
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15
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Various brain-eating amoebae: the protozoa, the pathogenesis, and the disease. Front Med 2021; 15:842-866. [PMID: 34825341 DOI: 10.1007/s11684-021-0865-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 04/25/2021] [Indexed: 10/19/2022]
Abstract
Among various genera of free-living amoebae prevalent in nature, some members are identified as causative agents of human encephalitis, in which Naegleria fowleri followed by Acanthamoeba spp. and Balamuthia mandrillaris have been successively discovered. As the three dominant genera responsible for infections, Acanthamoeba and Balamuthia work as opportunistic pathogens of granulomatous amoebic encephalitis in immunocompetent and immunocompromised individuals, whereas Naegleria induces primary amoebic meningoencephalitis mostly in healthy children and young adults as a more violent and deadly disease. Due to the lack of typical symptoms and laboratory findings, all these amoebic encephalitic diseases are difficult to diagnose. Considering that subsequent therapies are also affected, all these brain infections cause significant mortality worldwide, with more than 90% of the cases being fatal. Along with global warming and population explosion, expanding areas of human and amoebae activity in some regions lead to increased contact, resulting in more serious infections and drawing increased public attention. In this review, we summarize the present information of these pathogenic free-living amoebae, including their phylogeny, classification, biology, and ecology. The mechanisms of pathogenesis, immunology, pathophysiology, clinical manifestations, epidemiology, diagnosis, and therapies are also discussed.
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16
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Phan IQ, Rice CA, Craig J, Noorai RE, McDonald JR, Subramanian S, Tillery L, Barrett LK, Shankar V, Morris JC, Van Voorhis WC, Kyle DE, Myler PJ. The transcriptome of Balamuthia mandrillaris trophozoites for structure-guided drug design. Sci Rep 2021; 11:21664. [PMID: 34737367 PMCID: PMC8569187 DOI: 10.1038/s41598-021-99903-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Accepted: 09/27/2021] [Indexed: 11/09/2022] Open
Abstract
Balamuthia mandrillaris, a pathogenic free-living amoeba, causes cutaneous skin lesions as well as granulomatous amoebic encephalitis, a 'brain-eating' disease. As with the other known pathogenic free-living amoebas (Naegleria fowleri and Acanthamoeba species), drug discovery efforts to combat Balamuthia infections of the central nervous system are sparse; few targets have been validated or characterized at the molecular level, and little is known about the biochemical pathways necessary for parasite survival. Current treatments of encephalitis due to B. mandrillaris lack efficacy, leading to case fatality rates above 90%. Using our recently published methodology to discover potential drugs against pathogenic amoebas, we screened a collection of 85 compounds with known antiparasitic activity and identified 59 compounds that impacted the growth of Balamuthia trophozoites at concentrations below 220 µM. Since there is no fully annotated genome or proteome of B. mandrillaris, we sequenced and assembled its transcriptome from a high-throughput RNA-sequencing (RNA-Seq) experiment and located the coding sequences of the genes potentially targeted by the growth inhibitors from our compound screens. We determined the sequence of 17 of these target genes and obtained expression clones for 15 that we validated by direct sequencing. These will be used in the future in combination with the identified hits in structure guided drug discovery campaigns to develop new approaches for the treatment of Balamuthia infections.
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Affiliation(s)
- Isabelle Q Phan
- Seattle Structural Genomics Center for Infectious Disease (SSGCID), Seattle, WA, USA.
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA, USA.
| | - Christopher A Rice
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA, USA.
- Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, Athens, GA, USA.
| | - Justin Craig
- Seattle Structural Genomics Center for Infectious Disease (SSGCID), Seattle, WA, USA
- Center for Emerging and Re-Emerging Infectious Diseases (CERID), Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, WA, USA
| | - Rooksana E Noorai
- Clemson University Genomics and Bioinformatics Facility, Clemson University, Clemson, SC, USA
| | - Jacquelyn R McDonald
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA, USA
| | - Sandhya Subramanian
- Seattle Structural Genomics Center for Infectious Disease (SSGCID), Seattle, WA, USA
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA, USA
| | - Logan Tillery
- Seattle Structural Genomics Center for Infectious Disease (SSGCID), Seattle, WA, USA
- Center for Emerging and Re-Emerging Infectious Diseases (CERID), Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, WA, USA
| | - Lynn K Barrett
- Seattle Structural Genomics Center for Infectious Disease (SSGCID), Seattle, WA, USA
- Center for Emerging and Re-Emerging Infectious Diseases (CERID), Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, WA, USA
| | - Vijay Shankar
- Center for Human Genetics, Clemson University, Greenwood, SC, USA
| | - James C Morris
- Eukaryotic Pathogens Innovation Center, Department of Genetics and Biochemistry, Clemson University, Clemson, SC, USA
| | - Wesley C Van Voorhis
- Seattle Structural Genomics Center for Infectious Disease (SSGCID), Seattle, WA, USA
- Center for Emerging and Re-Emerging Infectious Diseases (CERID), Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, WA, USA
- Department of Microbiology, University of Washington, Seattle, WA, USA
- Department of Global Health, University of Washington, Seattle, WA, USA
| | - Dennis E Kyle
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA, USA
| | - Peter J Myler
- Seattle Structural Genomics Center for Infectious Disease (SSGCID), Seattle, WA, USA.
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA, USA.
- Department of Global Health, University of Washington, Seattle, WA, USA.
- Department of Pediatrics, University of Washington, Seattle, WA, USA.
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17
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Güémez A, García E. Primary Amoebic Meningoencephalitis by Naegleria fowleri: Pathogenesis and Treatments. Biomolecules 2021; 11:biom11091320. [PMID: 34572533 PMCID: PMC8469197 DOI: 10.3390/biom11091320] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2021] [Revised: 08/20/2021] [Accepted: 08/25/2021] [Indexed: 12/29/2022] Open
Abstract
Naegleria fowleri is a free-living amoeba (FLA) that is commonly known as the "brain-eating amoeba." This parasite can invade the central nervous system (CNS), causing an acute and fulminating infection known as primary amoebic meningoencephalitis (PAM). Even though PAM is characterized by low morbidity, it has shown a mortality rate of 98%, usually causing death in less than two weeks after the initial exposure. This review summarizes the most recent information about N. fowleri, its pathogenic molecular mechanisms, and the neuropathological processes implicated. Additionally, this review includes the main therapeutic strategies described in case reports and preclinical studies, including the possible use of immunomodulatory agents to decrease neurological damage.
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Herman EK, Greninger A, van der Giezen M, Ginger ML, Ramirez-Macias I, Miller HC, Morgan MJ, Tsaousis AD, Velle K, Vargová R, Záhonová K, Najle SR, MacIntyre G, Muller N, Wittwer M, Zysset-Burri DC, Eliáš M, Slamovits CH, Weirauch MT, Fritz-Laylin L, Marciano-Cabral F, Puzon GJ, Walsh T, Chiu C, Dacks JB. Genomics and transcriptomics yields a system-level view of the biology of the pathogen Naegleria fowleri. BMC Biol 2021; 19:142. [PMID: 34294116 PMCID: PMC8296547 DOI: 10.1186/s12915-021-01078-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Accepted: 06/24/2021] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND The opportunistic pathogen Naegleria fowleri establishes infection in the human brain, killing almost invariably within 2 weeks. The amoeba performs piece-meal ingestion, or trogocytosis, of brain material causing direct tissue damage and massive inflammation. The cellular basis distinguishing N. fowleri from other Naegleria species, which are all non-pathogenic, is not known. Yet, with the geographic range of N. fowleri advancing, potentially due to climate change, understanding how this pathogen invades and kills is both important and timely. RESULTS Here, we report an -omics approach to understanding N. fowleri biology and infection at the system level. We sequenced two new strains of N. fowleri and performed a transcriptomic analysis of low- versus high-pathogenicity N. fowleri cultured in a mouse infection model. Comparative analysis provides an in-depth assessment of encoded protein complement between strains, finding high conservation. Molecular evolutionary analyses of multiple diverse cellular systems demonstrate that the N. fowleri genome encodes a similarly complete cellular repertoire to that found in free-living N. gruberi. From transcriptomics, neither stress responses nor traits conferred from lateral gene transfer are suggested as critical for pathogenicity. By contrast, cellular systems such as proteases, lysosomal machinery, and motility, together with metabolic reprogramming and novel N. fowleri proteins, are all implicated in facilitating pathogenicity within the host. Upregulation in mouse-passaged N. fowleri of genes associated with glutamate metabolism and ammonia transport suggests adaptation to available carbon sources in the central nervous system. CONCLUSIONS In-depth analysis of Naegleria genomes and transcriptomes provides a model of cellular systems involved in opportunistic pathogenicity, uncovering new angles to understanding the biology of a rare but highly fatal pathogen.
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Affiliation(s)
- Emily K Herman
- Division of Infectious Disease, Department of Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Canada.
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada.
| | - Alex Greninger
- Laboratory Medicine and Medicine / Infectious Diseases, UCSF-Abbott Viral Diagnostics and Discovery Center, UCSF Clinical Microbiology Laboratory UCSF School of Medicine, San Francisco, USA
- Department of Laboratory Medicine, University of Washington Medical Center, Montlake, USA
| | - Mark van der Giezen
- Centre for Organelle Research, Department of Chemistry, Bioscience and Environmental Engineering, University of Stavanger, Stavanger, Norway
| | - Michael L Ginger
- School of Applied Sciences, Department of Biological and Geographical Sciences, University of Huddersfield, Huddersfield, UK
| | - Inmaculada Ramirez-Macias
- Division of Infectious Disease, Department of Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Canada
- Department of Cardiology, Hospital Clinico Universitario Virgen de la Arrixaca. Instituto Murciano de Investigación Biosanitaria. Centro de Investigación Biomedica en Red-Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain
| | - Haylea C Miller
- CSIRO Land and Water, Centre for Environment and Life Sciences, Private Bag No.5, Wembley, Western Australia 6913, Australia
- CSIRO, Indian Oceans Marine Research Centre, Environomics Future Science Platform, Crawley, WA, Australia
| | - Matthew J Morgan
- CSIRO Land and Water, Black Mountain Laboratories, Canberra, Australia
| | | | - Katrina Velle
- Department of Biology, University of Massachusetts, Amherst, UK
| | - Romana Vargová
- Department of Biology and Ecology, Faculty of Science, University of Ostrava, Ostrava, Czech Republic
| | - Kristína Záhonová
- Division of Infectious Disease, Department of Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Canada
- Faculty of Science, Charles University, BIOCEV, Prague, Czech Republic
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic
| | - Sebastian Rodrigo Najle
- Institut de Biologia Evolutiva (UPF-CSIC), Barcelona, Spain
- Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST), 08003, Barcelona, Catalonia, Spain
| | - Georgina MacIntyre
- Department of Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Canada
| | - Norbert Muller
- Institute of Parasitology, Vetsuisse Faculty Bern, University of Bern, Bern, Switzerland
| | - Mattias Wittwer
- Spiez Laboratory, Federal Office for Civil Protection, Austrasse, Spiez, Switzerland
| | - Denise C Zysset-Burri
- Department of Ophthalmology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Marek Eliáš
- Department of Biology and Ecology, Faculty of Science, University of Ostrava, Ostrava, Czech Republic
| | - Claudio H Slamovits
- Department of Biochemistry and Molecular Biology, Centre for Comparative Genomics and Evolutionary Bioinformatics, Dalhousie University, Halifax, Canada
| | - Matthew T Weirauch
- Center for Autoimmune Genomics and Etiology and Divisions of Biomedical Informatics and Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, USA
| | | | - Francine Marciano-Cabral
- Department of Microbiology and Immunology, Virginia Commonwealth University School of Medicine, Richmond, Virginia, USA
| | - Geoffrey J Puzon
- CSIRO Land and Water, Centre for Environment and Life Sciences, Private Bag No.5, Wembley, Western Australia 6913, Australia
| | - Tom Walsh
- CSIRO Land and Water, Black Mountain Laboratories, Canberra, Australia
| | - Charles Chiu
- Laboratory Medicine and Medicine / Infectious Diseases, UCSF-Abbott Viral Diagnostics and Discovery Center, UCSF Clinical Microbiology Laboratory UCSF School of Medicine, San Francisco, USA
| | - Joel B Dacks
- Division of Infectious Disease, Department of Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Canada.
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic.
- Department of Life Sciences, The Natural History Museum, London, UK.
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Wei L, Lu X, Weng S, Zhu S, Chen Y. Cholesteryl Ester Promotes Mammary Tumor Growth in MMTV-PyMT Mice and Activates Akt-mTOR Pathway in Tumor Cells. Biomolecules 2021; 11:biom11060853. [PMID: 34201030 PMCID: PMC8228430 DOI: 10.3390/biom11060853] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 05/24/2021] [Accepted: 05/25/2021] [Indexed: 11/16/2022] Open
Abstract
The association between intratumoral cholesteryl ester (CE) and tumor progression has been reported previously. The objective of our study was to investigate a causal effect of CE on mammary tumor progression. Using MMTV-PyMT (MMTV-polyoma virus middle T) transgenic mice and breast tumor cell MCF-7, we show that both exogenous and endogenous CE can increase mammary tumor growth, that CE upregulates the AKT/mTOR pathway, and that CE synthesis blockade suppresses this signaling pathway. Our data suggest that SOAT1, a sterol O-acyltransferase, may be a potential target for the treatment of breast cancer.
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Affiliation(s)
- Lengyun Wei
- Wuxi School of Medicine, Jiangnan University, Wuxi 214122, China; (L.W.); (X.L.); (S.W.); (S.Z.)
- Wuxi Translational Medicine Research Center and Jiangsu Translational Medicine Research Institute Wuxi Branch, Wuxi 214122, China
- School of Food Science and Technology, Jiangnan University, Wuxi 214122, China
| | - Xuyang Lu
- Wuxi School of Medicine, Jiangnan University, Wuxi 214122, China; (L.W.); (X.L.); (S.W.); (S.Z.)
- Wuxi Translational Medicine Research Center and Jiangsu Translational Medicine Research Institute Wuxi Branch, Wuxi 214122, China
- School of Food Science and Technology, Jiangnan University, Wuxi 214122, China
| | - Shengmei Weng
- Wuxi School of Medicine, Jiangnan University, Wuxi 214122, China; (L.W.); (X.L.); (S.W.); (S.Z.)
- Wuxi Translational Medicine Research Center and Jiangsu Translational Medicine Research Institute Wuxi Branch, Wuxi 214122, China
| | - Shenglong Zhu
- Wuxi School of Medicine, Jiangnan University, Wuxi 214122, China; (L.W.); (X.L.); (S.W.); (S.Z.)
- Wuxi Translational Medicine Research Center and Jiangsu Translational Medicine Research Institute Wuxi Branch, Wuxi 214122, China
| | - Yongquan Chen
- Wuxi School of Medicine, Jiangnan University, Wuxi 214122, China; (L.W.); (X.L.); (S.W.); (S.Z.)
- Wuxi Translational Medicine Research Center and Jiangsu Translational Medicine Research Institute Wuxi Branch, Wuxi 214122, China
- School of Food Science and Technology, Jiangnan University, Wuxi 214122, China
- Correspondence:
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Debnath A. Drug discovery for primary amebic meningoencephalitis: from screen to identification of leads. Expert Rev Anti Infect Ther 2021; 19:1099-1106. [PMID: 33496193 DOI: 10.1080/14787210.2021.1882302] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Introduction: Naegleria fowleri is responsible for primary amebic meningoencephalitis (PAM) which has a fatality rate of >97%. Because of the rarity of the disease, pharmaceutical companies do not pursue new drug discovery for PAM. Yet, it is possible that the infection is underreported and finding a better drug would have an impact on people suffering from this deadly infection.Areas covered: This paper reports the efforts undertaken by different academic groups over the last 20 years to test different compounds against N. fowleri. The drug discovery research encompassed synthesis of new compounds, development and use of high-throughput screening methods and attempts to repurpose clinically developed or FDA-approved compounds for the treatment of PAM.Expert opinion: In absence of economic investment to develop new drugs for PAM, repurposing the FDA-approved drugs has been the best strategy so far to identify new leads against N. fowleri. Increasing use of high-throughput phenotypic screening has the potential to accelerate the identification of new leads, either in monotherapy or in combination treatment. Since phase II clinical trial is not possible for PAM, it is critical to demonstrate in vivo efficacy of a clinically safe compound to translate the discovery from lab to the clinic.
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Affiliation(s)
- Anjan Debnath
- Center for Discovery and Innovation in Parasitic Diseases, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA, USA
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21
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Hahn HJ, Abagyan R, Podust LM, Roy S, Ali IKM, Debnath A. HMG-CoA Reductase Inhibitors as Drug Leads against Naegleria fowleri. ACS Chem Neurosci 2020; 11:3089-3096. [PMID: 32881478 DOI: 10.1021/acschemneuro.0c00428] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Primary amebic meningoencephalitis (PAM), caused by the free-living ameba Naegleria fowleri, has a fatality rate of over 97%. Treatment of PAM relies on amphotericin B in combination with other drugs, but few patients have survived with the existing drug treatment regimens. Therefore, development of effective drugs is a critical unmet need to avert deaths from PAM. Since ergosterol is one of the major sterols in the membrane of N. fowleri, disruption of isoprenoid and sterol biosynthesis by small-molecule inhibitors may be an effective intervention strategy against N. fowleri. The genome of N. fowleri contains a gene encoding HMG-CoA reductase (HMGR); the catalytic domains of human and N. fowleri HMGR share <60% sequence identity with only two amino acid substitutions in the active site of the enzyme. Considering the similarity of human and N. fowleri HMGR, we tested well-tolerated and widely used HMGR inhibitors, known as cholesterol-lowering statins, against N. fowleri. We identified blood-brain-barrier-permeable pitavastatin as a potent amebicidal agent against the U.S., Australian, and European strains of N. fowleri. Pitavastatin was equipotent to amphotericin B against the European strain of N. fowleri; it killed about 80% of trophozoites within 16 h of drug exposure. Pretreatment of trophozoites with mevalonate, the product of HMGR, rescued N. fowleri from inhibitory effects of statins, demonstrating that HMGR of N. fowleri is the target of statins. Because of the good safety profile and availability for both adult and pediatric uses, consideration should be given to repurposing the fast-acting pitavastatin for the treatment of PAM.
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Affiliation(s)
- Hye Jee Hahn
- Center for Discovery and Innovation in Parasitic Diseases, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, California 92093-0756, United States
| | - Ruben Abagyan
- Center for Discovery and Innovation in Parasitic Diseases, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, California 92093-0756, United States
| | - Larissa M. Podust
- Center for Discovery and Innovation in Parasitic Diseases, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, California 92093-0756, United States
| | - Shantanu Roy
- Free-Living and Intestinal Amebas (FLIA) Laboratory, Waterborne Disease Prevention Branch, Centers for Disease Control and Prevention (CDC), Atlanta, Georgia 30329-4018, United States
| | - Ibne Karim M. Ali
- Free-Living and Intestinal Amebas (FLIA) Laboratory, Waterborne Disease Prevention Branch, Centers for Disease Control and Prevention (CDC), Atlanta, Georgia 30329-4018, United States
| | - Anjan Debnath
- Center for Discovery and Innovation in Parasitic Diseases, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, California 92093-0756, United States
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Sharma V, Shing B, Hernandez-Alvarez L, Debnath A, Podust LM. Domain-Swap Dimerization of Acanthamoeba castellanii CYP51 and a Unique Mechanism of Inactivation by Isavuconazole. Mol Pharmacol 2020; 98:770-780. [PMID: 33008918 DOI: 10.1124/molpharm.120.000092] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Accepted: 09/17/2020] [Indexed: 01/14/2023] Open
Abstract
Cytochromes P450 (P450, CYP) metabolize a wide variety of endogenous and exogenous lipophilic molecules, including most drugs. Sterol 14α-demethylase (CYP51) is a target for antifungal drugs known as conazoles. Using X-ray crystallography, we have discovered a domain-swap homodimerization mode in CYP51 from a human pathogen, Acanthamoeba castellanii CYP51 (AcCYP51). Recombinant AcCYP51 with a truncated transmembrane helix was purified as a heterogeneous mixture corresponding to the dimer and monomer units. Spectral analyses of these two populations have shown that the CO-bound ferrous form of the dimeric protein absorbed at 448 nm (catalytically competent form), whereas the monomeric form absorbed at 420 nm (catalytically incompetent form). AcCYP51 dimerized head-to-head via N-termini swapping, resulting in formation of a nonplanar protein-protein interface exceeding 2000 Å2 with a total solvation energy gain of -35.4 kcal/mol. In the dimer, the protomers faced each other through the F and G α-helices, thus blocking the substrate access channel. In the presence of the drugs clotrimazole and isavuconazole, the AcCYP51 drug complexes crystallized as monomers. Although clotrimazole-bound AcCYP51 adopted a typical CYP monomer structure, isavuconazole-bound AcCYP51 failed to refold 74 N-terminal residues. The failure of AcCYP51 to fully refold upon inhibitor binding in vivo would cause an irreversible loss of a structurally aberrant enzyme through proteolytic degradation. This assumption explains the superior potency of isavuconazole against A. castellanii The dimerization mode observed in this work is compatible with membrane association and may be relevant to other members of the CYP family of biologic, medical, and pharmacological importance. SIGNIFICANCE STATEMENT: We investigated the mechanism of action of antifungal drugs in the human pathogen Acanthamoeba castellanii. We discovered that the enzyme target [Acanthamoeba castellanii sterol 14α-demethylase (AcCYP51)] formed a dimer via an N-termini swap, whereas drug-bound AcCYP51 was monomeric. In the AcCYP51-isavuconazole complex, the protein target failed to refold 74 N-terminal residues, suggesting a fundamentally different mechanism of AcCYP51 inactivation than only blocking the active site. Proteolytic degradation of a structurally aberrant enzyme would explain the superior potency of isavuconazole against A. castellanii.
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Affiliation(s)
- Vandna Sharma
- Skaggs School of Pharmacy and Pharmaceutical Sciences, Center for Discovery and Innovation in Parasitic Diseases, University of California San Diego, La Jolla, California (V.S., B.S., L.H.-A., A.D., L.M.P.) and Departamento de Física, Instituto de Biociências, Letras e Ciências Exatas, Universidade Estadual Paulista Julio de Mesquita Filho, São José do Rio Preto, São Paulo, Brazil (L.H.-A.)
| | - Brian Shing
- Skaggs School of Pharmacy and Pharmaceutical Sciences, Center for Discovery and Innovation in Parasitic Diseases, University of California San Diego, La Jolla, California (V.S., B.S., L.H.-A., A.D., L.M.P.) and Departamento de Física, Instituto de Biociências, Letras e Ciências Exatas, Universidade Estadual Paulista Julio de Mesquita Filho, São José do Rio Preto, São Paulo, Brazil (L.H.-A.)
| | - Lilian Hernandez-Alvarez
- Skaggs School of Pharmacy and Pharmaceutical Sciences, Center for Discovery and Innovation in Parasitic Diseases, University of California San Diego, La Jolla, California (V.S., B.S., L.H.-A., A.D., L.M.P.) and Departamento de Física, Instituto de Biociências, Letras e Ciências Exatas, Universidade Estadual Paulista Julio de Mesquita Filho, São José do Rio Preto, São Paulo, Brazil (L.H.-A.)
| | - Anjan Debnath
- Skaggs School of Pharmacy and Pharmaceutical Sciences, Center for Discovery and Innovation in Parasitic Diseases, University of California San Diego, La Jolla, California (V.S., B.S., L.H.-A., A.D., L.M.P.) and Departamento de Física, Instituto de Biociências, Letras e Ciências Exatas, Universidade Estadual Paulista Julio de Mesquita Filho, São José do Rio Preto, São Paulo, Brazil (L.H.-A.)
| | - Larissa M Podust
- Skaggs School of Pharmacy and Pharmaceutical Sciences, Center for Discovery and Innovation in Parasitic Diseases, University of California San Diego, La Jolla, California (V.S., B.S., L.H.-A., A.D., L.M.P.) and Departamento de Física, Instituto de Biociências, Letras e Ciências Exatas, Universidade Estadual Paulista Julio de Mesquita Filho, São José do Rio Preto, São Paulo, Brazil (L.H.-A.)
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Rice CA, Colon BL, Chen E, Hull MV, Kyle DE. Discovery of repurposing drug candidates for the treatment of diseases caused by pathogenic free-living amoebae. PLoS Negl Trop Dis 2020; 14:e0008353. [PMID: 32970675 PMCID: PMC7546510 DOI: 10.1371/journal.pntd.0008353] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 10/09/2020] [Accepted: 07/28/2020] [Indexed: 12/11/2022] Open
Abstract
Diseases caused by pathogenic free-living amoebae include primary amoebic meningoencephalitis (Naegleria fowleri), granulomatous amoebic encephalitis (Acanthamoeba spp.), Acanthamoeba keratitis, and Balamuthia amoebic encephalitis (Balamuthia mandrillaris). Each of these are difficult to treat and have high morbidity and mortality rates due to lack of effective therapeutics. Since repurposing drugs is an ideal strategy for orphan diseases, we conducted a high throughput phenotypic screen of 12,000 compounds from the Calibr ReFRAME library. We discovered a total of 58 potent inhibitors (IC50 <1 μM) against N. fowleri (n = 19), A. castellanii (n = 12), and B. mandrillaris (n = 27) plus an additional 90 micromolar inhibitors. Of these, 113 inhibitors have never been reported to have activity against Naegleria, Acanthamoeba or Balamuthia. Rapid onset of action is important for new anti-amoeba drugs and we identified 19 compounds that inhibit N. fowleri in vitro within 24 hours (halofuginone, NVP-HSP990, fumagillin, bardoxolone, belaronib, and BPH-942, solithromycin, nitracrine, quisinostat, pabinostat, pracinostat, dacinostat, fimepinostat, sanguinarium, radicicol, acriflavine, REP3132, BC-3205 and PF-4287881). These compounds inhibit N. fowleri in vitro faster than any of the drugs currently used for chemotherapy. The results of these studies demonstrate the utility of phenotypic screens for discovery of new drugs for pathogenic free-living amoebae, including Acanthamoeba for the first time. Given that many of the repurposed drugs have known mechanisms of action, these compounds can be used to validate new targets for structure-based drug design.
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Affiliation(s)
- Christopher A. Rice
- Department of Cellular Biology, University of Georgia, Athens, Georgia, United States of America
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, United States of America
- * E-mail: (CAR); (DEK)
| | - Beatrice L. Colon
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, United States of America
- Department of Infectious Diseases, University of Georgia, Athens, Georgia, United States of America
| | - Emily Chen
- Calibr at Scripps Research, La Jolla, California, United States of America
| | - Mitchell V. Hull
- Calibr at Scripps Research, La Jolla, California, United States of America
| | - Dennis E. Kyle
- Department of Cellular Biology, University of Georgia, Athens, Georgia, United States of America
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, United States of America
- Department of Infectious Diseases, University of Georgia, Athens, Georgia, United States of America
- * E-mail: (CAR); (DEK)
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In Vitro Evaluation of Farnesyltransferase Inhibitor and its Effect in Combination with 3-Hydroxy-3-Methyl-Glutaryl-CoA Reductase Inhibitor against Naegleria fowleri. Pathogens 2020; 9:pathogens9090689. [PMID: 32842691 PMCID: PMC7560193 DOI: 10.3390/pathogens9090689] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2020] [Revised: 08/20/2020] [Accepted: 08/21/2020] [Indexed: 11/18/2022] Open
Abstract
Free-living amoeba Naegleria fowleri causes a rapidly fatal infection primary amebic meningoencephalitis (PAM) in children. The drug of choice in treating PAM is amphotericin B, but very few patients treated with amphotericin B have survived PAM. Therefore, development of efficient drugs is a critical unmet need. We identified that the FDA-approved pitavastatin, an inhibitor of HMG Co-A reductase involved in the mevalonate pathway, was equipotent to amphotericin B against N. fowleri trophozoites. The genome of N. fowleri contains a gene encoding protein farnesyltransferase (FT), the last common enzyme for products derived from the mevalonate pathway. Here, we show that a clinically advanced FT inhibitor lonafarnib is active against different strains of N. fowleri with EC50 ranging from 1.5 to 9.2 µM. A combination of lonafarnib and pitavastatin at different ratios led to 95% growth inhibition of trophozoites and the combination achieved a dose reduction of about 2- to 28-fold for lonafarnib and 5- to 30-fold for pitavastatin. No trophozoite with normal morphology was found when trophozoites were treated for 48 h with a combination of 1.7 µM each of lonafarnib and pitavastatin. Combination of lonafarnib and pitavastatin may contribute to the development of a new drug regimen for the treatment of PAM.
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In Vitro Effect of Pitavastatin and Its Synergistic Activity with Isavuconazole against Acanthamoeba castellanii. Pathogens 2020; 9:pathogens9090681. [PMID: 32825652 PMCID: PMC7559540 DOI: 10.3390/pathogens9090681] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 08/18/2020] [Accepted: 08/19/2020] [Indexed: 02/06/2023] Open
Abstract
Acanthamoeba keratitis (AK) can occur in healthy individuals wearing contact lenses and it is a painful, blinding infection of the cornea caused by a free-living ameba Acanthamoeba. Current treatment for AK relies on a combination of chlorhexidine, propamidine isethionate, and polyhexamethylene biguanide. However, the current regimen includes an aggressive disinfectant and in 10% of cases recurrent infection ensues. Therefore, development of efficient and safe drugs is a critical unmet need to avert blindness. Acanthamoeba sterol biosynthesis includes two essential enzymes HMG-CoA reductase (HMGR) and sterol 14-demethylase (CYP51), and we earlier identified a CYP51 inhibitor isavuconazole that demonstrated nanomolar potency against A. castellanii trophozoites. In this study, we investigated the effect of well-tolerated HMGR inhibitors and identified pitavastatin that is active against trophozoites of three different clinical strains of A.castellanii. Pitavastatin demonstrated an EC50 of 0.5 to 1.9 µM, depending on strains. Combination of pitavastatin and isavuconazole is synergistic and led to 2- to 9-fold dose reduction for pitavastatin and 11- to 4000-fold dose reduction for isavuconazole to achieve 97% of growth inhibition. Pitavastatin, either alone or in combination with isavuconazole, may lead to repurposing for the treatment of Acanthamoeba keratitis.
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Escrig JI, Hahn HJ, Debnath A. Activity of Auranofin against Multiple Genotypes of Naegleria fowleri and Its Synergistic Effect with Amphotericin B In Vitro. ACS Chem Neurosci 2020; 11:2464-2471. [PMID: 32392039 DOI: 10.1021/acschemneuro.0c00165] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Primary amebic meningoencephalitis, caused by brain infection with a free-living ameba, Naegleria fowleri, leads to extensive inflammation of the brain and death within 3-7 days after symptoms begin. Treatment of primary amebic meningoencephalitis relies on amphotericin B in combination with other drugs, but use of amphotericin B is associated with severe adverse effects. Despite a fatality rate of over 97%, economic incentive to invest in development of antiamebic drugs by the pharmaceutical industry is lacking. Development of safe and rapidly acting drugs remains a critical unmet need to avert future deaths. Since FDA-approved anti-inflammatory and antiarthritic drug auranofin is a known inhibitor of selenoprotein synthesis and thioredoxin reductase and the genome of N. fowleri encodes genes for both selenocysteine biosynthesis and thioredoxin reductases, we tested the effect of auranofin against N. fowleri strains of different genotypes from the USA, Europe, and Australia. Auranofin was equipotent against all tested strains with an EC50 of 1-2 μM. Our growth inhibition study at different time points demonstrated that auranofin is fast-acting, and ∼90% growth inhibition was achieved within 16 h of drug exposure. A short exposure of N. fowleri to auranofin led to the accumulation of intracellular reactive oxygen species. This is consistent with auranofin's role in inhibiting antioxidant pathways. Further, combination of auranofin and amphotericin B led to 95% of growth inhibition with 2-9-fold dose reduction for amphotericin B and 3-20-fold dose reduction for auranofin. Auranofin has the potential to be repurposed for the treatment of primary amebic meningoencephalitis.
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Affiliation(s)
- Jose Ignacio Escrig
- Center for Discovery and Innovation in Parasitic Diseases, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California 92093-0756, United States
| | - Hye Jee Hahn
- Center for Discovery and Innovation in Parasitic Diseases, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California 92093-0756, United States
| | - Anjan Debnath
- Center for Discovery and Innovation in Parasitic Diseases, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California 92093-0756, United States
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Synthesis, Optimization, Antifungal Activity, Selectivity, and CYP51 Binding of New 2-Aryl-3-azolyl-1-indolyl-propan-2-ols. Pharmaceuticals (Basel) 2020; 13:ph13080186. [PMID: 32784450 PMCID: PMC7464559 DOI: 10.3390/ph13080186] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 07/29/2020] [Accepted: 08/05/2020] [Indexed: 12/14/2022] Open
Abstract
A series of 2-aryl-3-azolyl-1-indolyl-propan-2-ols was designed as new analogs of fluconazole (FLC) by replacing one of its two triazole moieties by an indole scaffold. Two different chemical approaches were then developed. The first one, in seven steps, involved the synthesis of the key intermediate 1-(1H-benzotriazol-1-yl)methyl-1H-indole and the final opening of oxiranes by imidazole or 1H-1,2,4-triazole. The second route allowed access to the target compounds in only three steps, this time with the ring opening by indole and analogs. Twenty azole derivatives were tested against Candida albicans and other Candida species. The enantiomers of the best anti-Candida compound, 2-(2,4-dichlorophenyl)-3-(1H-indol-1-yl)-1-(1H-1,2,4-triazol-1-yl)-propan-2-ol (8g), were analyzed by X-ray diffraction to determine their absolute configuration. The (−)-8g enantiomer (Minimum inhibitory concentration (MIC) = IC80 = 0.000256 µg/mL on C. albicans CA98001) was found with the S-absolute configuration. In contrast the (+)-8g enantiomer was found with the R-absolute configuration (MIC = 0.023 µg/mL on C. albicans CA98001). By comparison, the MIC value for FLC was determined as 0.020 µg/mL for the same clinical isolate. Additionally, molecular docking calculations and molecular dynamics simulations were carried out using a crystal structure of Candida albicans lanosterol 14α-demethylase (CaCYP51). The (−)-(S)-8g enantiomer aligned with the positioning of posaconazole within both the heme and access channel binding sites, which was consistent with its biological results. All target compounds have been also studied against human fetal lung fibroblast (MRC-5) cells. Finally, the selectivity of four compounds on a panel of human P450-dependent enzymes (CYP19, CYP17, CYP26A1, CYP11B1, and CYP11B2) was investigated.
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Rice CA, Troth EV, Russell AC, Kyle DE. Discovery of Anti-Amoebic Inhibitors from Screening the MMV Pandemic Response Box on Balamuthia mandrillaris, Naegleria fowleri, and Acanthamoeba castellanii. Pathogens 2020; 9:E476. [PMID: 32560115 PMCID: PMC7344389 DOI: 10.3390/pathogens9060476] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 06/05/2020] [Accepted: 06/09/2020] [Indexed: 02/06/2023] Open
Abstract
Pathogenic free-living amoebae, Balamuthia mandrillaris, Naegleria fowleri, and several Acanthamoeba species are the etiological agents of severe brain diseases, with case mortality rates > 90%. A number of constraints including misdiagnosis and partially effective treatments lead to these high fatality rates. The unmet medical need is for rapidly acting, highly potent new drugs to reduce these alarming mortality rates. Herein, we report the discovery of new drugs as potential anti-amoebic agents. We used the CellTiter-Glo 2.0 high-throughput screening methods to screen the Medicines for Malaria Ventures (MMV) Pandemic Response Box in a search for new active chemical scaffolds. Initially, we screened the library as a single-point assay at 10 and 1 µM. From these data, we reconfirmed hits by conducting quantitative dose-response assays and identified 12 hits against B. mandrillaris, 29 against N. fowleri, and 14 against A. castellanii ranging from nanomolar to low micromolar potency. We further describe 11 novel molecules with activity against B. mandrillaris, 22 against N. fowleri, and 9 against A. castellanii. These structures serve as a starting point for medicinal chemistry studies and demonstrate the utility of phenotypic screening for drug discovery to treat diseases caused by free-living amoebae.
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Affiliation(s)
- Christopher A. Rice
- Department of Cellular Biology, University of Georgia, Athens, GA 30602, USA
- Center for Tropical and Emerging Global Diseases, Athens, GA 30602, USA; (E.V.T.); (A.C.R.)
| | - Emma V. Troth
- Center for Tropical and Emerging Global Diseases, Athens, GA 30602, USA; (E.V.T.); (A.C.R.)
- Department of Infectious Diseases, University of Georgia, Athens, GA 30602, USA
| | - A. Cassiopeia Russell
- Center for Tropical and Emerging Global Diseases, Athens, GA 30602, USA; (E.V.T.); (A.C.R.)
- Department of Infectious Diseases, University of Georgia, Athens, GA 30602, USA
| | - Dennis E. Kyle
- Department of Cellular Biology, University of Georgia, Athens, GA 30602, USA
- Center for Tropical and Emerging Global Diseases, Athens, GA 30602, USA; (E.V.T.); (A.C.R.)
- Department of Infectious Diseases, University of Georgia, Athens, GA 30602, USA
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The Antifungal Drug Isavuconazole Is both Amebicidal and Cysticidal against Acanthamoeba castellanii. Antimicrob Agents Chemother 2020; 64:AAC.02223-19. [PMID: 32094126 DOI: 10.1128/aac.02223-19] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Accepted: 02/17/2020] [Indexed: 11/20/2022] Open
Abstract
Current treatments for Acanthamoeba keratitis rely on a combination of chlorhexidine gluconate, propamidine isethionate, and polyhexamethylene biguanide. These disinfectants are nonspecific and inherently toxic, which limits their effectiveness. Furthermore, in 10% of cases, recurrent infection ensues due to the difficulty in killing both trophozoites and double-walled cysts. Therefore, development of efficient, safe, and target-specific drugs which are capable of preventing recurrent Acanthamoeba infection is a critical unmet need for averting blindness. Since both trophozoites and cysts contain specific sets of membrane sterols, we hypothesized that antifungal drugs targeting sterol 14-demethylase (CYP51), known as conazoles, would have deleterious effects on A. castellanii trophozoites and cysts. To test this hypothesis, we first performed a systematic screen of the FDA-approved conazoles against A. castellanii trophozoites using a bioluminescence-based viability assay adapted and optimized for Acanthamoeba The most potent drugs were then evaluated against cysts. Isavuconazole and posaconazole demonstrated low nanomolar potency against trophozoites of three clinical strains of A. castellanii Furthermore, isavuconazole killed trophozoites within 24 h and suppressed excystment of preformed Acanthamoeba cysts into trophozoites. The rapid action of isavuconazole was also evident from the morphological changes at nanomolar drug concentrations causing rounding of trophozoites within 24 h of exposure. Given that isavuconazole has an excellent safety profile, is well tolerated in humans, and blocks A. castellanii excystation, this opens an opportunity for the cost-effective repurposing of isavuconazole for the treatment of primary and recurring Acanthamoeba keratitis.
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Ehrenkaufer G, Li P, Stebbins EE, Kangussu-Marcolino MM, Debnath A, White CV, Moser MS, DeRisi J, Gisselberg J, Yeh E, Wang SC, Company AH, Monti L, Caffrey CR, Huston CD, Wang B, Singh U. Identification of anisomycin, prodigiosin and obatoclax as compounds with broad-spectrum anti-parasitic activity. PLoS Negl Trop Dis 2020; 14:e0008150. [PMID: 32196500 PMCID: PMC7112225 DOI: 10.1371/journal.pntd.0008150] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 04/01/2020] [Accepted: 02/18/2020] [Indexed: 01/20/2023] Open
Abstract
Parasitic infections are a major source of human suffering, mortality, and economic loss, but drug development for these diseases has been stymied by the significant expense involved in bringing a drug though clinical trials and to market. Identification of single compounds active against multiple parasitic pathogens could improve the economic incentives for drug development as well as simplifying treatment regimens. We recently performed a screen of repurposed compounds against the protozoan parasite Entamoeba histolytica, causative agent of amebic dysentery, and identified four compounds (anisomycin, prodigiosin, obatoclax and nithiamide) with low micromolar potency and drug-like properties. Here, we extend our investigation of these drugs. We assayed the speed of killing of E. histolytica trophozoites and found that all four have more rapid action than the current drug of choice, metronidazole. We further established a multi-institute collaboration to determine whether these compounds may have efficacy against other parasites and opportunistic pathogens. We found that anisomycin, prodigiosin and obatoclax all have broad-spectrum antiparasitic activity in vitro, including activity against schistosomes, T. brucei, and apicomplexan parasites. In several cases, the drugs were found to have significant improvements over existing drugs. For instance, both obatoclax and prodigiosin were more efficacious at inhibiting the juvenile form of Schistosoma than the current standard of care, praziquantel. Additionally, low micromolar potencies were observed against pathogenic free-living amebae (Naegleria fowleri, Balamuthia mandrillaris and Acanthamoeba castellanii), which cause CNS infection and for which there are currently no reliable treatments. These results, combined with the previous human use of three of these drugs (obatoclax, anisomycin and nithiamide), support the idea that these compounds could serve as the basis for the development of broad-spectrum anti-parasitic drugs.
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Affiliation(s)
- Gretchen Ehrenkaufer
- Division of Infectious Diseases, Department of Internal Medicine, Stanford University, Stanford, CA, United States of America
| | - Pengyang Li
- Department of Bioengineering, Stanford University, Stanford, CA, United States of America
| | - Erin E. Stebbins
- Department of Medicine, University of Vermont Larner College of Medicine, Burlington, Vermont, United States of America
| | - Monica M. Kangussu-Marcolino
- Division of Infectious Diseases, Department of Internal Medicine, Stanford University, Stanford, CA, United States of America
| | - Anjan Debnath
- Center for Discovery and Innovation in Parasitic Diseases, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, United States of America
| | - Corin V. White
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, California, United States of America
| | - Matthew S. Moser
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, California, United States of America
| | - Joseph DeRisi
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, California, United States of America
| | - Jolyn Gisselberg
- Department of Biochemistry, Stanford Medical School, Stanford University, Stanford, CA, United States of America
| | - Ellen Yeh
- Department of Biochemistry, Stanford Medical School, Stanford University, Stanford, CA, United States of America
- Department of Microbiology and Immunology, Stanford University, Stanford, CA, United States of America
- Department of Pathology, Stanford University, Stanford, CA, United States of America
| | - Steven C. Wang
- Center for Discovery and Innovation in Parasitic Diseases, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, United States of America
| | - Ana Hervella Company
- Center for Discovery and Innovation in Parasitic Diseases, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, United States of America
| | - Ludovica Monti
- Center for Discovery and Innovation in Parasitic Diseases, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, United States of America
| | - Conor R. Caffrey
- Center for Discovery and Innovation in Parasitic Diseases, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, United States of America
| | - Christopher D. Huston
- Department of Medicine, University of Vermont Larner College of Medicine, Burlington, Vermont, United States of America
| | - Bo Wang
- Department of Bioengineering, Stanford University, Stanford, CA, United States of America
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA, United States of America
| | - Upinder Singh
- Division of Infectious Diseases, Department of Internal Medicine, Stanford University, Stanford, CA, United States of America
- Department of Microbiology and Immunology, Stanford University, Stanford, CA, United States of America
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31
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Colon BL, Rice CA, Guy RK, Kyle DE. Phenotypic Screens Reveal Posaconazole as a Rapidly Acting Amebicidal Combination Partner for Treatment of Primary Amoebic Meningoencephalitis. J Infect Dis 2020; 219:1095-1103. [PMID: 30358879 DOI: 10.1093/infdis/jiy622] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Accepted: 10/23/2018] [Indexed: 11/13/2022] Open
Abstract
Naegleria fowleri is the causative agent of primary amoebic meningoencephalitis (PAM), which is fatal in >97% of cases. In this study, we aimed to identify new, rapidly acting drugs to increase survival rates. We conducted phenotypic screens of libraries of Food and Drug Administration-approved compounds and the Medicines for Malaria Venture Pathogen Box and validated 14 hits (defined as a 50% inhibitory concentration of <1 μM). The hits were then prioritized by assessing the rate of action and efficacy in combination with current drugs used to treat PAM. Posaconazole was found to inhibit amoeba growth within the first 12 hours of exposure, which was faster than any currently used drug. In addition, posaconazole cured 33% of N. fowleri-infected mice at a dose of 20 mg/kg and, in combination with azithromycin, increased survival by an additional 20%. Fluconazole, which is currently used for PAM therapy, was ineffective in vitro and vivo. Our results suggest posaconazole could replace fluconazole in the treatment of PAM.
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Affiliation(s)
- Beatrice L Colon
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa.,Center for Tropical and Emerging Global Diseases, University of Georgia, Athens
| | - Christopher A Rice
- Department of Global Health, College of Public Health, University of South Florida, Tampa.,Center for Tropical and Emerging Global Diseases, University of Georgia, Athens
| | - R Kiplin Guy
- Department of Chemical Biology and Therapeutics, St Jude Children's Research Hospital, Memphis, Tennessee
| | - Dennis E Kyle
- Department of Global Health, College of Public Health, University of South Florida, Tampa.,Center for Tropical and Emerging Global Diseases, University of Georgia, Athens
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32
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Giray B, Karadağ AE, İpek ÖŞ, Pekel H, Güzel M, Küçük HB. Design and synthesis of novel cylopentapyrazoles bearing 1,2,3-thiadiazole moiety as potent antifungal agents. Bioorg Chem 2020; 95:103509. [DOI: 10.1016/j.bioorg.2019.103509] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 11/28/2019] [Accepted: 12/16/2019] [Indexed: 01/07/2023]
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33
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Shi D, Chahal KK, Oto P, Nothias LF, Debnath A, McKerrow JH, Podust LM, Abagyan R. Identification of Four Amoebicidal Nontoxic Compounds by a Molecular Docking Screen of Naegleria fowleri Sterol Δ8-Δ7-Isomerase and Phenotypic Assays. ACS Infect Dis 2019; 5:2029-2038. [PMID: 31583882 PMCID: PMC7085920 DOI: 10.1021/acsinfecdis.9b00227] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Naegleria fowleri is a free-living amoeba causing primary amoebic meningoencephalitis, a rapid-onset brain infection in humans with over 97% mortality rate. Despite some progress in the treatment of the disease, there is no single, proven, evidence-based treatment with a high probability of cure. Here we report the chemical library screening and experimental identification of four new compounds with amoebicidal effects against N. fowleri. The chemical library was screened by molecular docking against a homology model of sterol Δ8-Δ7 isomerase (NfERG2). Thirty top-ranking hits were then tested in a cell-based assay for antiproliferative/amoebicidal activities. Eight chemicals exhibited nearly 100% inhibition of N. fowleri at 50 μM, with the EC50 values ranging from 6 to 25 μM. A cell toxicity assay using human HEK-293 cells was also performed. Four of the compounds preferentially kill amoeba cells with no apparent human cell toxicities. These compounds fall into two distinct chemical scaffolds with druglike properties.
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Affiliation(s)
- Da Shi
- Skaggs School of Pharmacy and Pharmaceutical Science, University of California San Diego,9500 Gilman Drive, La Jolla, California, 92093, United States of America
| | - Kirti Kandhwal Chahal
- Skaggs School of Pharmacy and Pharmaceutical Science, University of California San Diego,9500 Gilman Drive, La Jolla, California, 92093, United States of America
- Department of Pharmaceutical Sciences, Guru Jambheshwar University of Science and Technology, Hisar-Delhi Bypass Road, Hisar, Haryana 125001, India
| | - Patricia Oto
- Skaggs School of Pharmacy and Pharmaceutical Science, University of California San Diego,9500 Gilman Drive, La Jolla, California, 92093, United States of America
| | - Louis-Felix Nothias
- Skaggs School of Pharmacy and Pharmaceutical Science, University of California San Diego,9500 Gilman Drive, La Jolla, California, 92093, United States of America
| | - Anjan Debnath
- Skaggs School of Pharmacy and Pharmaceutical Science, University of California San Diego,9500 Gilman Drive, La Jolla, California, 92093, United States of America
| | - James H. McKerrow
- Skaggs School of Pharmacy and Pharmaceutical Science, University of California San Diego,9500 Gilman Drive, La Jolla, California, 92093, United States of America
| | - Larissa M. Podust
- Skaggs School of Pharmacy and Pharmaceutical Science, University of California San Diego,9500 Gilman Drive, La Jolla, California, 92093, United States of America
| | - Ruben Abagyan
- Skaggs School of Pharmacy and Pharmaceutical Science, University of California San Diego,9500 Gilman Drive, La Jolla, California, 92093, United States of America
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34
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Kangussu-Marcolino MM, Ehrenkaufer GM, Chen E, Debnath A, Singh U. Identification of plicamycin, TG02, panobinostat, lestaurtinib, and GDC-0084 as promising compounds for the treatment of central nervous system infections caused by the free-living amebae Naegleria, Acanthamoeba and Balamuthia. Int J Parasitol Drugs Drug Resist 2019; 11:80-94. [PMID: 31707263 PMCID: PMC6849155 DOI: 10.1016/j.ijpddr.2019.10.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 09/18/2019] [Accepted: 10/17/2019] [Indexed: 01/11/2023]
Abstract
The free-living amebae Naegleria, Acanthamoeba, and Balamuthia cause rare but life-threatening infections. All three parasites can cause meningoencephalitis. Acanthamoeba can also cause chronic keratitis and both Balamuthia and Acanthamoeba can cause skin and systemic infections. There are minimal drug development pipelines for these pathogens despite a lack of available treatment regimens and high fatality rates. To identify anti-amebic drugs, we screened 159 compounds from a high-value repurposed library against trophozoites of the three amebae. Our efforts identified 38 compounds with activity against at least one ameba. Multiple drugs that bind the ATP-binding pocket of mTOR and PI3K are active, highlighting these compounds as important inhibitors of these parasites. Importantly, 24 active compounds have progressed at least to phase II clinical studies and overall 15 compounds were active against all three amebae. Based on central nervous system (CNS) penetration or exceptional potency against one amebic species, we identified sixteen priority compounds for the treatment of meningoencephalitis caused by these pathogens. The top five compounds are (i) plicamycin, active against all three free-living amebae and previously U.S. Food and Drug Administration (FDA) approved, (ii) TG02, active against all three amebae, (iii and iv) FDA-approved panobinostat and FDA orphan drug lestaurtinib, both highly potent against Naegleria, and (v) GDC-0084, a CNS penetrant mTOR inhibitor, active against at least two of the three amebae. These results set the stage for further investigation of these clinically advanced compounds for treatment of infections caused by the free-living amebae, including treatment of the highly fatal meningoencephalitis.
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Affiliation(s)
- Monica M Kangussu-Marcolino
- Division of Infectious Diseases, Department of Internal Medicine, Stanford University, Grant Building, S-143, 300 Pasteur Drive, Stanford, CA, 94305, USA
| | - Gretchen M Ehrenkaufer
- Division of Infectious Diseases, Department of Internal Medicine, Stanford University, Grant Building, S-143, 300 Pasteur Drive, Stanford, CA, 94305, USA
| | - Emily Chen
- uHTS Laboratory Rm 101, 11119 N Torrey Pines Rd. Calibr, A Division of the Scripps Research Institute, La Jolla, CA, 92037, USA
| | - Anjan Debnath
- Center for Discovery and Innovation in Parasitic Diseases, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Upinder Singh
- Division of Infectious Diseases, Department of Internal Medicine, Stanford University, Grant Building, S-143, 300 Pasteur Drive, Stanford, CA, 94305, USA; Department of Microbiology and Immunology, Stanford University, Stanford, CA, 94305, USA.
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35
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Jahangeer M, Mahmood Z, Munir N, Waraich U, Tahir IM, Akram M, Ali Shah SM, Zulfqar A, Zainab R. Naegleria fowleri: Sources of infection, pathophysiology, diagnosis, and management; a review. Clin Exp Pharmacol Physiol 2019; 47:199-212. [DOI: 10.1111/1440-1681.13192] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 10/07/2019] [Accepted: 10/12/2019] [Indexed: 12/14/2022]
Affiliation(s)
- Muhammad Jahangeer
- Department of Biochemistry Government College University Faisalabad Faisalabad Pakistan
| | - Zahed Mahmood
- Department of Biochemistry Government College University Faisalabad Faisalabad Pakistan
| | - Naveed Munir
- Department of Biochemistry Government College University Faisalabad Faisalabad Pakistan
- College of Allied Health Professionals Directorate of Medical Sciences Government College University Faisalabad Faisalabad Pakistan
| | | | - Imtiaz Mahmood Tahir
- College of Allied Health Professionals Directorate of Medical Sciences Government College University Faisalabad Faisalabad Pakistan
| | - Muhammad Akram
- Department of Eastern Medicine Directorate of Medical Sciences Government College University Faisalabad Faisalabad Pakistan
| | - Syed Muhammad Ali Shah
- Department of Eastern Medicine Directorate of Medical Sciences Government College University Faisalabad Faisalabad Pakistan
| | - Ayesha Zulfqar
- Department of Biochemistry Government College University Faisalabad Faisalabad Pakistan
| | - Rida Zainab
- Department of Eastern Medicine Directorate of Medical Sciences Government College University Faisalabad Faisalabad Pakistan
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36
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Jeffreys LN, Poddar H, Golovanova M, Levy CW, Girvan HM, McLean KJ, Voice MW, Leys D, Munro AW. Novel insights into P450 BM3 interactions with FDA-approved antifungal azole drugs. Sci Rep 2019; 9:1577. [PMID: 30733479 PMCID: PMC6367340 DOI: 10.1038/s41598-018-37330-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Accepted: 11/14/2018] [Indexed: 11/09/2022] Open
Abstract
Flavocytochrome P450 BM3 is a natural fusion protein constructed of cytochrome P450 and NADPH-cytochrome P450 reductase domains. P450 BM3 binds and oxidizes several mid- to long-chain fatty acids, typically hydroxylating these lipids at the ω-1, ω-2 and ω-3 positions. However, protein engineering has led to variants of this enzyme that are able to bind and oxidize diverse compounds, including steroids, terpenes and various human drugs. The wild-type P450 BM3 enzyme binds inefficiently to many azole antifungal drugs. However, we show that the BM3 A82F/F87V double mutant (DM) variant binds substantially tighter to numerous azole drugs than does the wild-type BM3, and that their binding occurs with more extensive heme spectral shifts indicative of complete binding of several azoles to the BM3 DM heme iron. We report here the first crystal structures of P450 BM3 bound to azole antifungal drugs - with the BM3 DM heme domain bound to the imidazole drugs clotrimazole and tioconazole, and to the triazole drugs fluconazole and voriconazole. This is the first report of any protein structure bound to the azole drug tioconazole, as well as the first example of voriconazole heme iron ligation through a pyrimidine nitrogen from its 5-fluoropyrimidine ring.
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Affiliation(s)
- Laura N Jeffreys
- Centre for Synthetic Biology of Fine and Specialty Chemicals (SYNBIOCHEM), Manchester Institute of Biotechnology, School of Chemistry, The University of Manchester, Manchester, M1 7DN, United Kingdom
| | - Harshwardhan Poddar
- Centre for Synthetic Biology of Fine and Specialty Chemicals (SYNBIOCHEM), Manchester Institute of Biotechnology, School of Chemistry, The University of Manchester, Manchester, M1 7DN, United Kingdom
| | - Marina Golovanova
- Centre for Synthetic Biology of Fine and Specialty Chemicals (SYNBIOCHEM), Manchester Institute of Biotechnology, School of Chemistry, The University of Manchester, Manchester, M1 7DN, United Kingdom
| | - Colin W Levy
- Manchester Protein Structure Facility (MPSF), Manchester Institute of Biotechnology, School of Chemistry, The University of Manchester, Manchester, M1 7DN, United Kingdom
| | - Hazel M Girvan
- Centre for Synthetic Biology of Fine and Specialty Chemicals (SYNBIOCHEM), Manchester Institute of Biotechnology, School of Chemistry, The University of Manchester, Manchester, M1 7DN, United Kingdom
| | - Kirsty J McLean
- Centre for Synthetic Biology of Fine and Specialty Chemicals (SYNBIOCHEM), Manchester Institute of Biotechnology, School of Chemistry, The University of Manchester, Manchester, M1 7DN, United Kingdom
| | - Michael W Voice
- Cypex Ltd., 6 Tom McDonald Avenue, Dundee DD2 1NH, Scotland, United Kingdom
| | - David Leys
- Centre for Synthetic Biology of Fine and Specialty Chemicals (SYNBIOCHEM), Manchester Institute of Biotechnology, School of Chemistry, The University of Manchester, Manchester, M1 7DN, United Kingdom
| | - Andrew W Munro
- Centre for Synthetic Biology of Fine and Specialty Chemicals (SYNBIOCHEM), Manchester Institute of Biotechnology, School of Chemistry, The University of Manchester, Manchester, M1 7DN, United Kingdom.
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37
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Zhou W, Debnath A, Jennings G, Hahn HJ, Vanderloop BH, Chaudhuri M, Nes WD, Podust LM. Enzymatic chokepoints and synergistic drug targets in the sterol biosynthesis pathway of Naegleria fowleri. PLoS Pathog 2018; 14:e1007245. [PMID: 30212566 PMCID: PMC6136796 DOI: 10.1371/journal.ppat.1007245] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Accepted: 07/27/2018] [Indexed: 11/29/2022] Open
Abstract
Naegleria fowleri is a free-living amoeba that can also act as an opportunistic pathogen causing severe brain infection, primary amebic meningoencephalitis (PAM), in humans. The high mortality rate of PAM (exceeding 97%) is attributed to (i) delayed diagnosis, (ii) lack of safe and effective anti-N. fowleri drugs, and (iii) difficulty of delivering drugs to the brain. Our work addresses identification of new molecular targets that may link anti-Naegleria drug discovery to the existing pharmacopeia of brain-penetrant drugs. Using inhibitors with known mechanism of action as molecular probes, we mapped the sterol biosynthesis pathway of N. fowleri by GC-MS analysis of metabolites. Based on this analysis, we chemically validated two enzymes downstream to CYP51, sterol C24-methyltransferase (SMT, ERG6) and sterol Δ8-Δ7 -isomerase (ERG2), as potential therapeutic drug targets in N. fowleri. The sterol biosynthetic cascade in N. fowleri displayed a mixture of canonical features peculiar to different domains of life: lower eukaryotes, plants and vertebrates. In addition to the cycloartenol→ergosterol biosynthetic route, a route leading to de novo cholesterol biosynthesis emerged. Isotopic labeling of the de novo-synthesized sterols by feeding N. gruberi trophozoites on the U13C-glucose-containing growth medium identified an exogenous origin of cholesterol, while 7-dehydrocholesterol (7DHC) had enriched 13C-content, suggesting a dual origin of this metabolite both from de novo biosynthesis and metabolism of scavenged cholesterol. Sterol homeostasis in Naegleria may be orchestrated over the course of its life-cycle by a "switch" between ergosterol and cholesterol biosynthesis. By demonstrating the growth inhibition and synergistic effects of the sterol biosynthesis inhibitors, we validated new, potentially druggable, molecular targets in N. fowleri. The similarity of the Naegleria sterol Δ8-Δ7 -isomerase to the human non-opioid σ1 receptor, implicated in human CNS conditions such as addiction, amnesia, pain and depression, provides an incentive to assess structurally diverse small-molecule brain-penetrant drugs targeting the human receptor for anti-Naegleria activity.
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Affiliation(s)
- Wenxu Zhou
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas, United States of America
| | - Anjan Debnath
- Center for Discovery and Innovation in Parasitic Diseases, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, California, United States of America
| | - Gareth Jennings
- Center for Discovery and Innovation in Parasitic Diseases, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, California, United States of America
| | - Hye Jee Hahn
- Center for Discovery and Innovation in Parasitic Diseases, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, California, United States of America
| | - Boden H. Vanderloop
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas, United States of America
| | - Minu Chaudhuri
- Department of Microbiology and Immunology, Meharry Medical College, Nashville, Tennessee, United States of America
| | - W. David Nes
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas, United States of America
| | - Larissa M. Podust
- Center for Discovery and Innovation in Parasitic Diseases, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, California, United States of America
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Zyserman I, Mondal D, Sarabia F, McKerrow JH, Roush WR, Debnath A. Identification of cysteine protease inhibitors as new drug leads against Naegleria fowleri. Exp Parasitol 2018; 188:36-41. [PMID: 29551628 DOI: 10.1016/j.exppara.2018.03.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2018] [Accepted: 03/13/2018] [Indexed: 10/17/2022]
Abstract
Primary amebic meningoencephalitis (PAM) is a rapidly fatal infection caused by the free-living ameba Naegleria fowleri. PAM occurs principally in healthy children of less than 13 years old with a history of recent exposure to warm fresh water. While as yet not a reportable disease, the Centers for Disease Control and Prevention (CDC) documents a total of 143 cases in the United States. Only four patients have survived. Infection results from water containing N. fowleri entering the nose, followed by migration of the amebae to the brain. Within the brain, N. fowleri infection results in extensive necrosis, leading to death in 3-7 days. Mortality among patients with PAM is greater than 95%. The drugs of choice in treating PAM are the antifungal amphotericin B, and the antileishmanial, miltefosine. However neither drug is FDA-approved for this indication and the use of amphotericin B is associated with severe adverse effects. Moreover, very few patients treated with amphotericin B have survived PAM. Therefore, development of new, safe and effective drugs is a critical unmet need to avert future deaths of children. The molecular mechanisms underlying the pathogenesis of PAM are poorly understood but it is known that cysteine proteases of N. fowleri play a role in the progression of PAM. We therefore assessed the in vitro activity of the synthetic vinyl sulfone cysteine protease inhibitor, K11777, and 33 analogs with valine, phenylalanine or pyridylalanine at P2 position, against cysteine protease activity in the lysate of N. fowleri. Inhibitors with phenylalanine or pyridylalanine at P2 position were particularly effective in inhibiting the cysteine protease activity of N. fowleri cell lysate with IC50 ranging between 3 nM and 6.6 μM. Three of the 34 inhibitors also showed inhibitory activity against N. fowleri in a cell viability assay and were 1.6- to 2.5-fold more potent than the standard of care drug miltefosine. Our study provides the first evidence of the activity of synthetic, small molecule cysteine protease inhibitors against N. fowleri.
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Affiliation(s)
- Ingrid Zyserman
- Center for Discovery and Innovation in Parasitic Diseases, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, 9500 Gilman Drive, MC0755, La Jolla, CA 92093-0755, USA
| | - Deboprosad Mondal
- The Scripps Research Institute, Scripps Florida, 130 Scripps Way #3A2, Jupiter, FL 33458, USA
| | - Francisco Sarabia
- The Scripps Research Institute, Scripps Florida, 130 Scripps Way #3A2, Jupiter, FL 33458, USA
| | - James H McKerrow
- Center for Discovery and Innovation in Parasitic Diseases, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, 9500 Gilman Drive, MC0755, La Jolla, CA 92093-0755, USA
| | - William R Roush
- The Scripps Research Institute, Scripps Florida, 130 Scripps Way #3A2, Jupiter, FL 33458, USA
| | - Anjan Debnath
- Center for Discovery and Innovation in Parasitic Diseases, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, 9500 Gilman Drive, MC0755, La Jolla, CA 92093-0755, USA.
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Debnath A, Nelson AT, Silva-Olivares A, Shibayama M, Siegel D, McKerrow JH. In Vitro Efficacy of Ebselen and BAY 11-7082 Against Naegleria fowleri. Front Microbiol 2018; 9:414. [PMID: 29559968 PMCID: PMC5845744 DOI: 10.3389/fmicb.2018.00414] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Accepted: 02/21/2018] [Indexed: 11/13/2022] Open
Abstract
Primary amebic meningoencephalitis (PAM) is a fatal infection caused by the free-living ameba Naegleria fowleri, popularly known as the "brain-eating ameba." The drugs of choice in treating PAM are the antifungal amphotericin B and an antileishmanial miltefosine, but these are not FDA-approved for this indication and use of amphotericin B is associated with severe adverse effects. Moreover, very few patients treated with the combination therapy have survived PAM. Therefore, development of efficient drugs is a critical unmet need to avert future deaths of children. Since N. fowleri causes extensive inflammation in the brain it is important to select compounds that can enter brain to kill ameba. In this study, we identified two central nervous system (CNS) active compounds, ebselen and BAY 11-7082 as amebicidal with EC50 of 6.2 and 1.6 μM, respectively. The closely related BAY 11-7085 was also found active against N. fowleri with EC50 similar to BAY 11-7082. We synthesized a soluble ebselen analog, which had amebicidal activity similar to ebselen. Transmission electron microscopy of N. fowleri trophozoites incubated for 48 h with EC50 concentration of ebselen showed alteration in the cytoplasmic membrane, loss of the nuclear membrane, and appearance of electron-dense granules. Incubation of N. fowleri trophozoites with EC50 concentrations of BAY 11-7082 and BAY 11-7085 for 48 h showed the presence of large lipid droplets in the cytoplasm, disruption of cytoplasmic and nuclear membranes and appearance of several vesicles and chromatin residues. Blood-brain barrier permeable amebicidal compounds have potential as new drug leads for Naegleria infection.
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Affiliation(s)
- Anjan Debnath
- Center for Discovery and Innovation in Parasitic Diseases, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, United States
| | - Andrew T Nelson
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, United States
| | - Angélica Silva-Olivares
- Department of Infectomics and Molecular Pathogenesis, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
| | - Mineko Shibayama
- Department of Infectomics and Molecular Pathogenesis, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
| | - Dionicio Siegel
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, United States
| | - James H McKerrow
- Center for Discovery and Innovation in Parasitic Diseases, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, United States
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