1
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Hargrove T, Lamb DC, Wawrzak Z, Hull M, Kelly SL, Guengerich FP, Lepesheva GI. Identification of Potent and Selective Inhibitors of Acanthamoeba: Structural Insights into Sterol 14α-Demethylase as a Key Drug Target. J Med Chem 2024; 67:7443-7457. [PMID: 38683753 PMCID: PMC11089504 DOI: 10.1021/acs.jmedchem.4c00303] [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: 02/02/2024] [Revised: 03/27/2024] [Accepted: 04/22/2024] [Indexed: 05/02/2024]
Abstract
Acanthamoeba are free-living pathogenic protozoa that cause blinding keratitis, disseminated infection, and granulomatous amebic encephalitis, which is generally fatal. The development of efficient and safe drugs is a critical unmet need. Acanthamoeba sterol 14α-demethylase (CYP51) is an essential enzyme of the sterol biosynthetic pathway. Repurposing antifungal azoles for amoebic infections has been reported, but their inhibitory effects on Acanthamoeba CYP51 enzymatic activity have not been studied. Here, we report catalytic properties, inhibition, and structural characterization of CYP51 from Acanthamoeba castellanii. The enzyme displays a 100-fold substrate preference for obtusifoliol over lanosterol, supporting the plant-like cycloartenol-based pathway in the pathogen. The strongest inhibition was observed with voriconazole (1 h IC50 0.45 μM), VT1598 (0.25 μM), and VT1161 (0.20 μM). The crystal structures of A. castellanii CYP51 with bound VT1161 (2.24 Å) and without an inhibitor (1.95 Å), presented here, can be used in the development of azole-based scaffolds to achieve optimal amoebicidal effectiveness.
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Affiliation(s)
- Tatiana
Y. Hargrove
- Department
of Biochemistry, Vanderbilt University School
of Medicine, Nashville, Tennessee 37232, United States
| | - David C. Lamb
- Faculty
of Medicine, Health and Life Science, Swansea
University, Swansea SA2 8PP, U.K.
| | - Zdzislaw Wawrzak
- Synchrotron
Research Center, Life Science Collaborative Access Team, Northwestern University, Argonne, Illinois 60439, United States
| | - Marcus Hull
- Faculty
of Medicine, Health and Life Science, Swansea
University, Swansea SA2 8PP, U.K.
| | - Steven L. Kelly
- Faculty
of Medicine, Health and Life Science, Swansea
University, Swansea SA2 8PP, U.K.
| | - F. Peter Guengerich
- Department
of Biochemistry, Vanderbilt University School
of Medicine, Nashville, Tennessee 37232, United States
| | - Galina I. Lepesheva
- Department
of Biochemistry, Vanderbilt University School
of Medicine, Nashville, Tennessee 37232, United States
- Vanderbilt
Institute of Chemical Biology, Nashville, Tennessee 37232, United States
- Center
for Structural Biology, Vanderbilt University, Nashville, Tennessee 37232, United States
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2
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de Araújo JIF, Aires NL, Almeida-Neto FWQ, Marinho MM, Marinho EM, Paula Magalhães E, de Menezes RRPPB, Sampaio TL, Maria Costa Martins A, Teixeira EH, Rafaela Freitas Dotto A, Amaral WD, Teixeira AMR, de Lima-Neto P, Marinho ES, Dos Santos HS. Antiproliferative activity on Trypanosoma cruzi (Y strain) of the triterpene 3β,6β,16β-trihidroxilup-20 (29)-ene isolated from Combretum leprosum. J Biomol Struct Dyn 2022; 40:12302-12315. [PMID: 34436980 DOI: 10.1080/07391102.2021.1970025] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Chagas disease infects approximately seven million people worldwide. Benznidazole is effective only in the acute phase of the disease, with an average cure rate of 80% between acute and recent cases. Therefore, there is an urgent need to find new bioactive substances that can be effective against parasites without causing so many complications to the host. In this study, the triterpene 3β-6β-16β-trihydroxilup-20 (29)-ene (CLF-1) was isolated from Combretum leprosum, and its molecular structure was determined by NMR and infrared spectroscopy. The CLF-1 was also evaluated in vitro and in silico as potential trypanocidal agent against epimastigote and trypomastigote forms of Trypanosoma cruzi (Y strain). The CLF-1 demonstrated good results highlighted by lower IC50 (76.0 ± 8.72 µM, 75.1 ± 11.0 µM, and 70.3 ± 45.4 µM) for epimastigotes at 24, 48 and 72 h, and LC50 (71.6 ± 11.6 µM) for trypomastigotes forms. The molecular docking study shows that the CLF-1 was able to interact with important TcGAPDH residues, suggesting that this natural compound may preferentially exert its effect by compromising the glycolytic pathway in T. cruzi. The ADMET study together with the MTT results indicated that the CLF-1 is well-absorbed in the intestine and has low toxicity. Thus, this work adds new evidence that CLF-1 can potentially be used as a candidate for the development of new options for the treatment of Chagas disease.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- José Ismael F de Araújo
- Programa de Pós-Graduação em Biotecnologia - PPGB-Renorbio, Universidade Estadual do Ceará, Fortaleza, CE, Brazil
| | - Natália L Aires
- Laboratório de Bioprospecção Farmacêutica e Bioquímica Clínica (LBFBC), Departamento de Análises Clínicas e Toxicológicas, Universidade Federal do Ceará, Fortaleza, Brazil
| | | | - Márcia M Marinho
- Faculdade de Educação, Ciência e Letras de Iguatu, Universidade Estadual do Ceará, Iguatu, Brazil
| | - Emanuelle M Marinho
- Departamento de Química Analítica e Físico-Química, Universidade Federal do Ceará, Fortaleza, Brazil
| | - Emanuel Paula Magalhães
- Laboratório de Bioprospecção Farmacêutica e Bioquímica Clínica (LBFBC), Departamento de Análises Clínicas e Toxicológicas, Universidade Federal do Ceará, Fortaleza, Brazil
| | - Ramon R P P B de Menezes
- Laboratório de Bioprospecção Farmacêutica e Bioquímica Clínica (LBFBC), Departamento de Análises Clínicas e Toxicológicas, Universidade Federal do Ceará, Fortaleza, Brazil
| | - Tiago L Sampaio
- Laboratório de Bioprospecção Farmacêutica e Bioquímica Clínica (LBFBC), Departamento de Análises Clínicas e Toxicológicas, Universidade Federal do Ceará, Fortaleza, Brazil
| | - Alice Maria Costa Martins
- Laboratório de Bioprospecção Farmacêutica e Bioquímica Clínica (LBFBC), Departamento de Análises Clínicas e Toxicológicas, Universidade Federal do Ceará, Fortaleza, Brazil
| | - Edson H Teixeira
- Laboratório Integrado de Biomoléculas (LIBS), Departamento de Patologia e Medicina Legal, Universidade Federal do Ceará, Fortaleza, Brazil
| | - Ana Rafaela Freitas Dotto
- Programa de Pós-Graduação em Desenvolvimento Territorial Sustentável, Universidade Federal do Paraná, Matinhos, PR, Brazil
| | - Wanderlei do Amaral
- Departamento de Engenharia Química, Universidade Federal do Paraná, Curitiba, Paraná, Brasil
| | - Alexandre Magno R Teixeira
- Programa de Pós-Graduação em Biotecnologia - PPGB-Renorbio, Universidade Estadual do Ceará, Fortaleza, CE, Brazil.,Departamento de Química Biológica, Universidade Regional do Cariri, Crato, Brazil
| | - Pedro de Lima-Neto
- Departamento de Química Analítica e Físico-Química, Universidade Federal do Ceará, Fortaleza, Brazil
| | - Emmanuel S Marinho
- Faculdade de Filosofia Dom Aureliano Matos, Universidade Estadual do Ceará, Limoeiro do Norte, Brazil
| | - Hélcio S Dos Santos
- Programa de Pós-Graduação em Biotecnologia - PPGB-Renorbio, Universidade Estadual do Ceará, Fortaleza, CE, Brazil.,Centro de Ciencias Exatas e Tecnologia, Universidade Estadual do Vale do Acaraú, Sobral, Brazil.,Departamento de Química Biológica, Universidade Regional do Cariri, Crato, Brazil
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3
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Rocha YM, Magalhães EP, de Medeiros Chaves M, Machado Marinho M, Nascimento E Melo de Oliveira V, Nascimento de Oliveira R, Lima Sampaio T, de Menezes RRPPB, Martins AMC, Nicolete R. Antiparasitary and antiproliferative activities in vitro of a 1,2,4-oxadiazole derivative on Trypanosoma cruzi. Parasitol Res 2022; 121:2141-2156. [PMID: 35610523 DOI: 10.1007/s00436-022-07554-z] [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: 10/18/2021] [Accepted: 05/13/2022] [Indexed: 11/26/2022]
Abstract
Chagas disease (CD) is a neglected disease, prevalent and endemic in Latin America, but also present in Europe and North America. The main treatment used for this disease is benznidazole, but its efficacy is variable in the chronic phase and presents high toxicity. So, there is a need for the development of new therapeutic agents. The five-membered heterocyclic 1,2,4-oxadiazole ring has received attention for its unique properties and a broad spectrum of biological activities and is therefore a potential candidate for the development of new drugs. Thus, the aim of this study was to evaluate the activity of the N-cyclohexyl-3-(3-methylphenyl)-1,2,4-oxadiazol-5-amine (2) on the evolutionary forms of Trypanosoma cruzi strain Y, as well as its mechanisms of action and in silico theoretical approach. The results by computational method showed an interaction of the 1,2,4-oxadiazole (2) with TcGAPDH, cruzain, and trypanothione reductase, showing good charge distribution and affinity in those three targets. Furthermore, cytotoxicity in LLC-MK2 cells was performed by the MTT method. In the assays with different parasite forms, the tested compound showed similar time-dependent concentration effect. The evaluation of the antiamastigote effect between the two concentrations tested showed a reduction in the number of infected cells and also in the number of amastigotes per infected cell. By flow cytometry, the compound (2) displayed alterations suggestive of necrotic events. Finally, in scanning electron microscopy structural alterations were present, characteristic of necrosisin the epimastigote forms. Overall, the 1,2,4-oxadiazole derivative (2) here evaluated opens perspectives to the development of new antichagasic agents.
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Affiliation(s)
- Yasmim Mendes Rocha
- Post-Graduate Program in Pharmaceutical Sciences - Federal University of Ceará, Fortaleza, CE, Brazil
- Fundação Oswaldo Cruz (Fiocruz Ceará), Rua São José, S/N, Eusébio, 61760-000, Brazil
| | - Emanuel Paula Magalhães
- Post-Graduate Program in Pharmaceutical Sciences - Federal University of Ceará, Fortaleza, CE, Brazil
| | | | - Márcia Machado Marinho
- Department of Clinical and Toxicological Analysis, Federal University of Ceará, Fortaleza, Ceará, Brazil
| | - Valentina Nascimento E Melo de Oliveira
- Department of Chemistry, Federal Rural University of Pernambuco, Recife, PE, Brazil
- Instituto Federal de Educação Ciência E Tecnologia de Pernambuco, Campus Ipojuca, Ipojuca, 55590-000, Brazil
| | | | - Tiago Lima Sampaio
- Post-Graduate Program in Pharmaceutical Sciences - Federal University of Ceará, Fortaleza, CE, Brazil
- Department of Clinical and Toxicological Analysis, Federal University of Ceará, Fortaleza, Ceará, Brazil
| | - Ramon R P P B de Menezes
- Post-Graduate Program in Pharmaceutical Sciences - Federal University of Ceará, Fortaleza, CE, Brazil
- Department of Clinical and Toxicological Analysis, Federal University of Ceará, Fortaleza, Ceará, Brazil
| | - Alice M C Martins
- Post-Graduate Program in Pharmaceutical Sciences - Federal University of Ceará, Fortaleza, CE, Brazil
- Department of Clinical and Toxicological Analysis, Federal University of Ceará, Fortaleza, Ceará, Brazil
| | - Roberto Nicolete
- Post-Graduate Program in Pharmaceutical Sciences - Federal University of Ceará, Fortaleza, CE, Brazil.
- Fundação Oswaldo Cruz (Fiocruz Ceará), Rua São José, S/N, Eusébio, 61760-000, Brazil.
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4
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Hargrove TY, Wawrzak Z, Rachakonda G, Nes WD, Villalta F, Guengerich FP, Lepesheva GI. Relaxed Substrate Requirements of Sterol 14α-Demethylase from Naegleria fowleri Are Accompanied by Resistance to Inhibition. J Med Chem 2021; 64:17511-17522. [PMID: 34842434 DOI: 10.1021/acs.jmedchem.1c01710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Naegleria fowleri is the protozoan pathogen that causes primary amoebic meningoencephalitis (PAM), with the death rate exceeding 97%. The amoeba makes sterols and can be targeted by sterol biosynthesis inhibitors. Here, we characterized N. fowleri sterol 14-demethylase, including catalytic properties and inhibition by clinical antifungal drugs and experimental substituted azoles with favorable pharmacokinetics and low toxicity. None of them inhibited the enzyme stoichiometrically. The highest potencies were displayed by posaconazole (IC50 = 0.69 μM) and two of our compounds (IC50 = 1.3 and 0.35 μM). Because both these compounds penetrate the brain with concentrations reaching minimal inhibitory concentration (MIC) values in an N. fowleri cellular assay, we report them as potential drug candidates for PAM. The 2.1 Å crystal structure, in complex with the strongest inhibitor, provides an explanation connecting the enzyme weaker substrate specificity with lower sensitivity to inhibition. It also provides insight into the enzyme/ligand molecular recognition process and suggests directions for the design of more potent inhibitors.
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Affiliation(s)
- Tatiana Y Hargrove
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
| | - Zdzislaw Wawrzak
- Synchrotron Research Center, Life Science Collaborative Access Team, Northwestern University, Argonne, Illinois 60439, United States
| | - Girish Rachakonda
- Department of Microbiology, Immunology and Physiology, Meharry Medical College, Nashville, Tennessee 37208, United States
| | - W David Nes
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409, United States
| | - Fernando Villalta
- Department of Microbiology, Immunology and Physiology, Meharry Medical College, Nashville, Tennessee 37208, United States
| | - F Peter Guengerich
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
| | - Galina I Lepesheva
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States.,Center for Structural Biology, Vanderbilt University, Nashville, Tennessee 37232, United States
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5
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Franco CH, Warhurst DC, Bhattacharyya T, Au HYA, Le H, Giardini MA, Pascoalino BS, Torrecilhas AC, Romera LMD, Madeira RP, Schenkman S, Freitas-Junior LH, Chatelain E, Miles MA, Moraes CB. Novel structural CYP51 mutation in Trypanosoma cruzi associated with multidrug resistance to CYP51 inhibitors and reduced infectivity. INTERNATIONAL JOURNAL FOR PARASITOLOGY-DRUGS AND DRUG RESISTANCE 2020; 13:107-120. [PMID: 32688218 PMCID: PMC7369355 DOI: 10.1016/j.ijpddr.2020.06.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Revised: 05/29/2020] [Accepted: 06/04/2020] [Indexed: 12/31/2022]
Abstract
Ergosterol biosynthesis inhibitors, such as posaconazole and ravuconazole, have been proposed as drug candidates for Chagas disease, a neglected infectious tropical disease caused by the protozoan parasite Trypanosoma cruzi. To understand better the mechanism of action and resistance to these inhibitors, a clone of the T. cruzi Y strain was cultured under intermittent and increasing concentrations of ravuconazole until phenotypic stability was achieved. The ravuconazole-selected clone exhibited loss in fitness in vitro when compared to the wild-type parental clone, as observed in reduced invasion capacity and slowed population growth in both mammalian and insect stages of the parasite. In drug activity assays, the resistant clone was above 300-fold more tolerant to ravuconazole than the sensitive parental clone, when the half-maximum effective concentration (EC50) was considered. The resistant clones also showed reduced virulence in vivo, when compared to parental sensitive clones. Cross-resistance to posaconazole and other CYP51 inhibitors, but not to other antichagasic drugs that act independently of CYP51, such as benznidazole and nifurtimox, was also observed. A novel amino acid residue change, T297M, was found in the TcCYP51 gene in the resistant but not in the sensitive clones. The structural effects of the T297M, and of the previously described P355S residue changes, were modelled to understand their impact on interaction with CYP51 inhibitors. A ravuconazole-resistant T. cruzi clone presented reduced in vitro and in vivo fitness. The ravuconazole-resistant clone presented cross-resistance to other CYP51 inhibitors. There was no cross-resistance to benznidazole and nifurtimox. Resistance is associated with a novel structural mutation in the TcCYP51 protein.
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Affiliation(s)
- Caio H Franco
- Laboratório Nacional de Biociências (LNBio), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Campinas, SP, Brazil; Department of Microbiology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil
| | - David C Warhurst
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - Tapan Bhattacharyya
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - Ho Y A Au
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - Hai Le
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - Miriam A Giardini
- Institut Pasteur Korea, Bundang-gu, Seongnam-si, Gyeonggi-do, Republic of Korea
| | - Bruno S Pascoalino
- Laboratório Nacional de Biociências (LNBio), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Campinas, SP, Brazil
| | - Ana Claudia Torrecilhas
- Department of Pharmaceutical Sciences, Federal University of São Paulo (UNIFESP), Diadema, SP, Brazil
| | - Lavinia M D Romera
- Department of Pharmaceutical Sciences, Federal University of São Paulo (UNIFESP), Diadema, SP, Brazil
| | - Rafael Pedro Madeira
- Department of Pharmaceutical Sciences, Federal University of São Paulo (UNIFESP), Diadema, SP, Brazil
| | - Sergio Schenkman
- Department of Microbiology, Immunology and Parasitology, UNIFESP, São Paulo, SP, Brazil
| | - Lucio H Freitas-Junior
- Department of Microbiology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil; Institut Pasteur Korea, Bundang-gu, Seongnam-si, Gyeonggi-do, Republic of Korea
| | - Eric Chatelain
- Drugs for Neglected Diseases Initiative, Geneva, Switzerland
| | - Michael A Miles
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - Carolina B Moraes
- Laboratório Nacional de Biociências (LNBio), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Campinas, SP, Brazil; Department of Microbiology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil; Institut Pasteur Korea, Bundang-gu, Seongnam-si, Gyeonggi-do, Republic of Korea; Department of Pharmaceutical Sciences, Federal University of São Paulo (UNIFESP), Diadema, SP, Brazil.
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6
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Villalta F, Rachakonda G. Advances in preclinical approaches to Chagas disease drug discovery. Expert Opin Drug Discov 2019; 14:1161-1174. [PMID: 31411084 PMCID: PMC6779130 DOI: 10.1080/17460441.2019.1652593] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Accepted: 08/02/2019] [Indexed: 12/21/2022]
Abstract
Introduction: Chagas disease affects 8-10 million people worldwide, mainly in Latin America. The current therapy for Chagas disease is limited to nifurtimox and benznidazole, which are effective in treating only the acute phase of the disease but with severe side effects. Therefore, there is an unmet need for new drugs and for the exploration of innovative approaches which may lead to the discovery of new effective and safe drugs for its treatment. Areas covered: The authors report and discuss recent approaches including structure-based design that have led to the discovery of new promising small molecule candidates for Chagas disease which affect prime targets that intervene in the sterol pathway of T. cruzi. Other trypanosome targets, phenotypic screening, the use of artificial intelligence and the challenges with Chagas disease drug discovery are also discussed. Expert opinion: The application of recent scientific innovations to the field of Chagas disease have led to the discovery of new promising drug candidates for Chagas disease. Phenotypic screening brought new hits and opportunities for drug discovery. Artificial intelligence also has the potential to accelerate drug discovery in Chagas disease and further research into this is warranted.
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Affiliation(s)
- Fernando Villalta
- Department of Microbiology, Immunology and Physiology, School of Medicine, Meharry Medical College , Nashville , TN , USA
| | - Girish Rachakonda
- Department of Microbiology, Immunology and Physiology, School of Medicine, Meharry Medical College , Nashville , TN , USA
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7
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Antiparasitic effect of (-)-α-bisabolol against Trypanosoma cruzi Y strain forms. Diagn Microbiol Infect Dis 2019; 95:114860. [PMID: 31353066 DOI: 10.1016/j.diagmicrobio.2019.06.012] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 05/20/2019] [Accepted: 06/18/2019] [Indexed: 12/22/2022]
Abstract
Chagas disease is caused by Trypanosoma cruzi and affects about 7 million people worldwide. Benznidazole and nifurtimox have low efficacy and high toxicity. The present study was designed to identify the trypanocidal effect of (-)-α-Bisabolol (BIS) and investigate its mechanism. Epimastigotes and trypomastigotes were cultured with BIS and the viable cells were counted. BIS antiamastigote effect was evaluated using infected LLC-MK2 cells. MTT assay was performed to evaluate BIS cytotoxicity. Growth recovery was assessed to evaluate BIS effect after short times of exposure. BIS mechanism was investigated through flow cytometry, with 7-AAD and Annexin V-PE. DCFH-DA, rhodamine 123 (Rho123) and acridine orange (AO). Finally, enzymatic and computational assays were performed to identify BIS interaction with T. cruzi GAPDH (tcGAPDH). BIS showed an inhibitory effect on epimastigotes after all tested periods, as well on trypomastigotes. It caused cytotoxicity on LLC-MK2 cells at higher concentrations, with selectivity index (SeI) = 26.5. After treatment, infected cells showed a decrease in infected cells, the number of amastigotes per infected cell and the survival index (SuI). Growth recovery demonstrated that BIS effect causes rapid death of T. cruzi. Flow cytometry showed that BIS biological effect is associated with apoptosis induction, increase in cytoplasmic ROS and mitochondrial transmembrane potential, while reservosome swelling was observed at a late stage. Also, BIS action mechanism may be associated to tcGAPDH inhibition. Altogether, the results demonstrate that BIS causes cell death in Trypanosoma cruzi Y strain forms, with the involvement of apoptosis and oxidative stress and enzymatic inhibition.
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8
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Guedes-da-Silva FH, Batista DDGJ, Da Silva CF, Pavão BP, Batista MM, Moreira OC, Souza LRQ, Britto C, Rachakonda G, Villalta F, Lepesheva GI, Soeiro MDNC. Successful Aspects of the Coadministration of Sterol 14α-Demethylase Inhibitor VFV and Benznidazole in Experimental Mouse Models of Chagas Disease Caused by the Drug-Resistant Strain of Trypanosoma cruzi. ACS Infect Dis 2019; 5:365-371. [PMID: 30625275 DOI: 10.1021/acsinfecdis.8b00253] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Up to now, no vaccines are available for Chagas disease, and the current therapy is largely unsatisfactory. Novel imidazole-based scaffolds of protozoan sterol 14α-demethylase (CYP51) inhibitors have demonstrated potent antiparasitic activity with no acute toxicity. Presently our aim was to investigate the effectiveness of the experimental 14α-demethylase inhibitor VFV in the mouse models of Trypanosoma cruzi infection using a naturally drug-resistant Colombiana strain, under monotherapy and in association with the reference drug, benznidazole (Bz). The treatment with VFV resulted in complete parasitemia suppression and 100% animal survival when administered orally (given in 10% DMSO plus 5% Arabic gum) at 25 mg/kg (bid) for 60 days. However, as parasite relapse was found using VFV alone under this treatment scheme, the coadministration of VFV with Bz was assayed giving simultaneously (for 60 days, bid) by oral route, under two different drug vehicles (10% DMSO plus 5% Gum Arabic with or without 3% Tween 80). All tested mice groups resulted in >99.9% of parasitemia decrease and 100% animal survival. qPCR analysis performed on cyclophosphamide immunosuppressed mice revealed that, although presenting lack of cure, VFV given as monotherapy was 14-fold more active than Bz, and the coadministration of Bz plus VFV (given simultaneously, using 10% DMSO plus 5% Gum Arabic as vehicle) resulted in 106-fold lower blood parasitism as compared to the monotherapy of Bz. Another interesting finding was the parasitological cure in 70% of the animals treated with Bz and VFV when the coadministration was given using the VFV suspension in 10% DMSO + Arabic gum + Tween 80 (a formulation that we have found to provide a better pharmacokinetics), even after immunosuppression using cyclophosphamide cycles, supporting the promising aspect of the drug coadministration in improving the efficacy of therapeutic arsenal against T. cruzi.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Girish Rachakonda
- Department of Microbiology, Immunology, and Physiology, Meharry Medical College, 1005 Dr. DB Todd Jr. Blvd., Nashville, Tennessee 37208, United States,
| | - Fernando Villalta
- Department of Microbiology, Immunology, and Physiology, Meharry Medical College, 1005 Dr. DB Todd Jr. Blvd., Nashville, Tennessee 37208, United States,
| | - Galina I. Lepesheva
- Department of Biochemistry School of Medicine, Institute for Global Health, Vanderbilt University, 622A RRB, 2200 Pierce Avenue, Nashville, Tennessee 37232, United States
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9
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Lepesheva GI, Friggeri L, Waterman MR. CYP51 as drug targets for fungi and protozoan parasites: past, present and future. Parasitology 2018; 145:1820-1836. [PMID: 29642960 PMCID: PMC6185833 DOI: 10.1017/s0031182018000562] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The efficiency of treatment of human infections with the unicellular eukaryotic pathogens such as fungi and protozoa remains deeply unsatisfactory. For example, the mortality rates from nosocomial fungemia in critically ill, immunosuppressed or post-cancer patients often exceed 50%. A set of six systemic clinical azoles [sterol 14α-demethylase (CYP51) inhibitors] represents the first-line antifungal treatment. All these drugs were discovered empirically, by monitoring their effects on fungal cell growth, though it had been proven that they kill fungal cells by blocking the biosynthesis of ergosterol in fungi at the stage of 14α-demethylation of the sterol nucleus. This review briefs the history of antifungal azoles, outlines the situation with the current clinical azole-based drugs, describes the attempts of their repurposing for treatment of human infections with the protozoan parasites that, similar to fungi, also produce endogenous sterols, and discusses the most recently acquired knowledge on the CYP51 structure/function and inhibition. It is our belief that this information should be helpful in shifting from the traditional phenotypic screening to the actual target-driven drug discovery paradigm, which will rationalize and substantially accelerate the development of new, more efficient and pathogen-oriented CYP51 inhibitors.
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Affiliation(s)
- Galina I. Lepesheva
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA
| | - Laura Friggeri
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA
| | - Michael R. Waterman
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA
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Friggeri L, Hargrove TY, Rachakonda G, Blobaum AL, Fisher P, de Oliveira GM, da Silva CF, Soeiro MDNC, Nes WD, Lindsley CW, Villalta F, Guengerich FP, Lepesheva GI. Sterol 14α-Demethylase Structure-Based Optimization of Drug Candidates for Human Infections with the Protozoan Trypanosomatidae. J Med Chem 2018; 61:10910-10921. [PMID: 30451500 DOI: 10.1021/acs.jmedchem.8b01671] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Sterol 14α-demethylases (CYP51) are cytochrome P450 enzymes essential for sterol biosynthesis in eukaryotes and therapeutic targets for antifungal azoles. Multiple attempts to repurpose antifungals for treatment of human infections with protozoa (Trypanosomatidae) have been undertaken, yet so far none of them have revealed sufficient efficacy. VNI and its derivative VFV are two potent experimental inhibitors of Trypanosomatidae CYP51, effective in vivo against Chagas disease, visceral leishmaniasis, and sleeping sickness and currently under consideration as antiprotozoal drug candidates. However, VNI is less potent against Leishmania and drug-resistant strains of Trypanosoma cruzi and VFV, while displaying a broader spectrum of antiprotozoal activity, and is metabolically less stable. In this work we have designed, synthesized, and characterized a set of close analogues and identified two new compounds (7 and 9) that exceed VNI/VFV in their spectra of antiprotozoal activity, microsomal stability, and pharmacokinetics (tissue distribution in particular) and, like VNI/VFV, reveal no acute toxicity.
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Affiliation(s)
- Laura Friggeri
- Department of Biochemistry , Vanderbilt University School of Medicine , Nashville , Tennessee 37232 , United States
| | - Tatiana Y Hargrove
- Department of Biochemistry , Vanderbilt University School of Medicine , Nashville , Tennessee 37232 , United States
| | - Girish Rachakonda
- Department of Microbiology, Immunology and Physiology , Meharry Medical College , Nashville , Tennessee 37208 , United States
| | - Anna L Blobaum
- Vanderbilt Center for Neuroscience Drug Discovery , Franklin , Tennessee 37067 , United States
| | - Paxtyn Fisher
- Department of Chemistry and Biochemistry , Texas Tech University , Lubbock , Texas 79409 , United States
| | - Gabriel Melo de Oliveira
- Laboratório de Biologia Celular , Instituto Oswaldo Cruz , Fundação Oswaldo Cruz , Rio de Janeiro , RJ 21040-360 , Brazil
| | - Cristiane França da Silva
- Laboratório de Biologia Celular , Instituto Oswaldo Cruz , Fundação Oswaldo Cruz , Rio de Janeiro , RJ 21040-360 , Brazil
| | - Maria de Nazaré C Soeiro
- Laboratório de Biologia Celular , Instituto Oswaldo Cruz , Fundação Oswaldo Cruz , Rio de Janeiro , RJ 21040-360 , Brazil
| | - W David Nes
- Department of Chemistry and Biochemistry , Texas Tech University , Lubbock , Texas 79409 , United States
| | - Craig W Lindsley
- Vanderbilt Center for Neuroscience Drug Discovery , Franklin , Tennessee 37067 , United States
| | - Fernando Villalta
- Department of Microbiology, Immunology and Physiology , Meharry Medical College , Nashville , Tennessee 37208 , United States
| | - F Peter Guengerich
- Department of Biochemistry , Vanderbilt University School of Medicine , Nashville , Tennessee 37232 , United States
| | - Galina I Lepesheva
- Department of Biochemistry , Vanderbilt University School of Medicine , Nashville , Tennessee 37232 , United States.,Center for Structural Biology , Vanderbilt University , Nashville , Tennessee 37232 , United States
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Sousa PL, Souza RODS, Tessarolo LD, de Menezes RRPPB, Sampaio TL, Canuto JA, Martins AMC. Betulinic acid induces cell death by necrosis in Trypanosoma cruzi. Acta Trop 2017; 174:72-75. [PMID: 28690148 DOI: 10.1016/j.actatropica.2017.07.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Revised: 06/15/2017] [Accepted: 07/05/2017] [Indexed: 01/31/2023]
Abstract
Chagas' disease is a neglected disease caused by the protozoan parasite Trypanosoma cruzi and constitutes a serious health problem worldwide. The treatment is limited, with variable efficacy of benznidazole and nifurtimox. Betulinic Acid (BA), a triterpene, can be found in medicinal herbs and has a wide variety of biological and pharmacological activities. The objective was to evaluate betulinic acid effects on the cell death mechanism in Trypanosoma cruzi strain Y. BA inhibited the growth of epimastigotes in periods of 24h (IC50=73.43μM), 48h (IC50=119.8μM) and 72h (IC50=212.2μM) of incubation; of trypomastigotes (IC50=51.88μM) in periods of 24h and intracellular amastigotes (IC50=25.94μM) in periods of 24 and 48h of incubation, no toxicity on LLC-MK2 cells at the concentrations used. Analysis of the possible mechanism of parasite cell death showed alterations in mitochondrial membrane potential, alterations in cell membrane integrity, an increase in the formation of reactive oxygen species and increase swelling of the reservosomes. In conclusion, betulinic acid was be able to inhibition all developmental forms of Trypanosoma cruzi Y strain with necrotic mechanism and involvement of mitochondrial membrane potential alteration and increase in reactive oxygen species.
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Crystal Structure of the New Investigational Drug Candidate VT-1598 in Complex with Aspergillus fumigatus Sterol 14α-Demethylase Provides Insights into Its Broad-Spectrum Antifungal Activity. Antimicrob Agents Chemother 2017; 61:AAC.00570-17. [PMID: 28461309 DOI: 10.1128/aac.00570-17] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Accepted: 04/17/2017] [Indexed: 01/08/2023] Open
Abstract
Within the past few decades, the incidence and complexity of human fungal infections have increased, and therefore, the need for safer and more efficient, broad-spectrum antifungal agents is high. In the study described here, we characterized the new tetrazole-based drug candidate VT-1598 as an inhibitor of sterol 14α-demethylase (CYP51B) from the filamentous fungus Aspergillus fumigatus VT-1598 displayed a high affinity of binding to the enzyme in solution (dissociation constant, 13 ± 1 nM) and in the reconstituted enzymatic reaction was revealed to have an inhibitory potency stronger than the potencies of all other simultaneously tested antifungal drugs, including fluconazole, voriconazole, ketoconazole, and posaconazole. The X-ray structure of the VT-1598/A. fumigatus CYP51 complex was determined and depicts the distinctive binding mode of the inhibitor in the enzyme active site, suggesting the molecular basis of the improved drug potency and broad-spectrum antifungal activity. These data show the formation of an optimized hydrogen bond between the phenoxymethyl oxygen of VT-1598 and the imidazole ring nitrogen of His374, the CYP51 residue that is highly conserved across fungal pathogens and fungus specific. Comparative structural analysis of A. fumigatus CYP51/voriconazole and Candida albicans CYP51/VT-1161 complexes supports the role of H bonding in fungal CYP51/inhibitor complexes and emphasizes the importance of an optimal distance between this interaction and the inhibitor-heme iron interaction. Cellular experiments using two A. fumigatus strains (strains 32820 and 1022) displayed a direct correlation between the effects of the drugs on CYP51B activity and fungal growth inhibition, indicating the noteworthy anti-A. fumigatus potency of VT-1598 and confirming its promise as a broad-spectrum antifungal agent.
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Antitrypanosomal Activity of Sterol 14α-Demethylase (CYP51) Inhibitors VNI and VFV in the Swiss Mouse Models of Chagas Disease Induced by the Trypanosoma cruzi Y Strain. Antimicrob Agents Chemother 2017; 61:AAC.02098-16. [PMID: 28167559 DOI: 10.1128/aac.02098-16] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Accepted: 01/22/2017] [Indexed: 11/20/2022] Open
Abstract
Chagas disease is a life-threatening infection caused by a variety of genetically diverse strains of the protozoan parasite Trypanosoma cruzi The current treatment (benznidazole and nifurtimox) is unsatisfactory, and potential alternatives include inhibitors of sterol 14α-demethylase (CYP51), the cytochrome P450 enzyme essential for the biosynthesis of sterols in eukaryotes and the major target of clinical and agricultural antifungals. Here we performed a comparative investigation of two protozoon-specific CYP51 inhibitors, VNI and its CYP51 structure-based derivative VFV, in the murine models of infection caused by the Y strain of T. cruzi The effects of different treatment regimens and drug delivery vehicles were evaluated in animals of both genders, with benznidazole serving as the reference drug. Regardless of the treatment scheme or delivery vehicle, VFV was more potent in both genders, causing a >99.7% peak parasitemia reduction, while the VNI values varied from 91 to 100%. Treatments with VNI and VFV resulted in 100% animal survival and 0% natural relapse after the end of therapy, though, except for the 120-day treatment schemes with VFV, relapses after three cycles of immunosuppression were observed in each animal group, and quantitative PCR analysis revealed a very light parasite load in the blood samples (sometimes below or near the detection limit, which was 1.5 parasite equivalents/ml). Our studies support further investigations of this class of compounds, including their testing against other T. cruzi strains and in combination with other drugs.
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Hargrove TY, Friggeri L, Wawrzak Z, Qi A, Hoekstra WJ, Schotzinger RJ, York JD, Guengerich FP, Lepesheva GI. Structural analyses of Candida albicans sterol 14α-demethylase complexed with azole drugs address the molecular basis of azole-mediated inhibition of fungal sterol biosynthesis. J Biol Chem 2017; 292:6728-6743. [PMID: 28258218 DOI: 10.1074/jbc.m117.778308] [Citation(s) in RCA: 212] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Revised: 02/20/2017] [Indexed: 12/27/2022] Open
Abstract
With some advances in modern medicine (such as cancer chemotherapy, broad exposure to antibiotics, and immunosuppression), the incidence of opportunistic fungal pathogens such as Candida albicans has increased. Cases of drug resistance among these pathogens have become more frequent, requiring the development of new drugs and a better understanding of the targeted enzymes. Sterol 14α-demethylase (CYP51) is a cytochrome P450 enzyme required for biosynthesis of sterols in eukaryotic cells and is the major target of clinical drugs for managing fungal pathogens, but some of the CYP51 key features important for rational drug design have remained obscure. We report the catalytic properties, ligand-binding profiles, and inhibition of enzymatic activity of C. albicans CYP51 by clinical antifungal drugs that are used systemically (fluconazole, voriconazole, ketoconazole, itraconazole, and posaconazole) and topically (miconazole and clotrimazole) and by a tetrazole-based drug candidate, VT-1161 (oteseconazole: (R)-2-(2,4-difluorophenyl)-1,1-difluoro-3-(1H-tetrazol-1-yl)-1-(5-(4-(2,2,2-trifluoroethoxy)phenyl)pyridin-2-yl)propan-2-ol). Among the compounds tested, the first-line drug fluconazole was the weakest inhibitor, whereas posaconazole and VT-1161 were the strongest CYP51 inhibitors. We determined the X-ray structures of C. albicans CYP51 complexes with posaconazole and VT-1161, providing a molecular mechanism for the potencies of these drugs, including the activity of VT-1161 against Candida krusei and Candida glabrata, pathogens that are intrinsically resistant to fluconazole. Our comparative structural analysis outlines phylum-specific CYP51 features that could direct future rational development of more efficient broad-spectrum antifungals.
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Affiliation(s)
- Tatiana Y Hargrove
- From the Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232
| | - Laura Friggeri
- From the Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232
| | - Zdzislaw Wawrzak
- the Synchrotron Research Center, Life Science Collaborative Access Team, Northwestern University, Argonne, Illinois 60439
| | - Aidong Qi
- From the Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232
| | | | | | - John D York
- From the Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232
| | - F Peter Guengerich
- From the Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232
| | - Galina I Lepesheva
- From the Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, .,the Center for Structural Biology, Vanderbilt University, Nashville, Tennessee 37232
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Abstract
INTRODUCTION Chagas disease is a chronic infection associated with long-term morbidity. Increased funding and advocacy for drug discovery for neglected diseases have prompted the introduction of several important technological advances, and Chagas disease is among the neglected conditions that has mostly benefited from technological developments. A number of screening campaigns, and the development of new and improved in vitro and in vivo assays, has led to advances in the field of drug discovery. AREAS COVERED This review highlights the major advances in Chagas disease drug screening, and how these are being used not only to discover novel chemical entities and drug candidates, but also increase our knowledge about the disease and the parasite. Different methodologies used for compound screening and prioritization are discussed, as well as novel techniques for the investigation of these targets. The molecular mechanism of action is also discussed. EXPERT OPINION Technological advances have been executed with scientific rigour for the development of new in vitro cell-based assays and in vivo animal models, to bring about novel and better drugs for Chagas disease, as well as to increase our understanding of what are the necessary properties for a compound to be successful in the clinic. The gained knowledge, combined with new exciting approaches toward target deconvolution, will help identifying new targets for Chagas disease chemotherapy in the future.
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Affiliation(s)
- Carolina B Moraes
- a Laboratório Nacional de Biociências (LNBio) , Centro Nacional de Pesquisa em Energia e Materiais (CNPEM) , Campinas , Brazil
| | - Caio H Franco
- a Laboratório Nacional de Biociências (LNBio) , Centro Nacional de Pesquisa em Energia e Materiais (CNPEM) , Campinas , Brazil.,b Graduate Program in Microbiology and Immunology , Universidade Federal de Sao Paulo , Sao Paulo , Brazil
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Clinical Candidate VT-1161's Antiparasitic Effect In Vitro, Activity in a Murine Model of Chagas Disease, and Structural Characterization in Complex with the Target Enzyme CYP51 from Trypanosoma cruzi. Antimicrob Agents Chemother 2015; 60:1058-66. [PMID: 26643331 DOI: 10.1128/aac.02287-15] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Accepted: 11/23/2015] [Indexed: 01/08/2023] Open
Abstract
A novel antifungal drug candidate, the 1-tetrazole-based agent VT-1161 [(R)-2-(2,4-difluorophenyl)-1,1-difluoro-3-(1H-tetrazol-1-yl)-1-{5-[4-(2,2,2-trifluoroethoxy)phenyl]pyridin-2-yl}propan-2-ol], which is currently in two phase 2b antifungal clinical trials, was found to be a tight-binding ligand (apparent dissociation constant [Kd], 24 nM) and a potent inhibitor of cytochrome P450 sterol 14α-demethylase (CYP51) from the protozoan pathogen Trypanosoma cruzi. Moreover, VT-1161 revealed a high level of antiparasitic activity against amastigotes of the Tulahuen strain of T. cruzi in cellular experiments (50% effective concentration, 2.5 nM) and was active in vivo, causing >99.8% suppression of peak parasitemia in a mouse model of infection with the naturally drug-resistant Y strain of the parasite. The data strongly support the potential utility of VT-1161 in the treatment of Chagas disease. The structural characterization of T. cruzi CYP51 in complex with VT-1161 provides insights into the molecular basis for the compound's inhibitory potency and paves the way for the further rational development of this novel, tetrazole-based inhibitory chemotype both for antiprotozoan chemotherapy and for antifungal chemotherapy.
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Different Therapeutic Outcomes of Benznidazole and VNI Treatments in Different Genders in Mouse Experimental Models of Trypanosoma cruzi Infection. Antimicrob Agents Chemother 2015; 59:7564-70. [PMID: 26416857 DOI: 10.1128/aac.01294-15] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Accepted: 09/19/2015] [Indexed: 01/17/2023] Open
Abstract
The lack of translation between preclinical assays and clinical trials for novel therapies for Chagas disease (CD) indicates a need for more feasible and standardized protocols and experimental models. Here, we investigated the effects of treatment with benznidazole (Bz) and with the potent experimental T. cruzi CYP51 inhibitor VNI in mouse models of Chagas disease by using different animal genders and parasite strains and employing distinct types of therapeutic schemes. Our findings confirm that female mice are less vulnerable to the infection than males, show that male models are less susceptible to treatment with both Bz and VNI, and thus suggest that male models are much more suitable for selection of the most promising antichagasic agents. Additionally, we have found that preventive protocols (compound given at 1 dpi) result in higher treatment success rates, which also should be avoided during advanced steps of in vivo trials of novel anti-T. cruzi drug candidates. Another consideration is the relevance of immunosuppression methods in order to verify the therapeutic profile of novel compounds, besides the usefulness of molecular diagnostic tools (quantitative PCR) to ascertain compound efficacy in experimental animals. Our study aims to contribute to the development of more reliable methods and decision gates for in vivo assays of novel antiparasitic compounds in order to move them from preclinical to clinical trials for CD.
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Hargrove TY, Wawrzak Z, Lamb DC, Guengerich FP, Lepesheva GI. Structure-Functional Characterization of Cytochrome P450 Sterol 14α-Demethylase (CYP51B) from Aspergillus fumigatus and Molecular Basis for the Development of Antifungal Drugs. J Biol Chem 2015; 290:23916-34. [PMID: 26269599 DOI: 10.1074/jbc.m115.677310] [Citation(s) in RCA: 101] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Indexed: 01/18/2023] Open
Abstract
Aspergillus fumigatus is the opportunistic fungal pathogen that predominantly affects the immunocompromised population and causes 600,000 deaths/year. The cytochrome P450 51 (CYP51) inhibitor voriconazole is currently the drug of choice, yet the treatment efficiency remains low, calling for rational development of more efficient agents. A. fumigatus has two CYP51 genes, CYP51A and CYP51B, which share 59% amino acid sequence identity. CYP51B is expressed constitutively, whereas gene CYP51A is reported to be inducible. We expressed, purified, and characterized A. fumigatus CYP51B, including determination of its substrate preferences, catalytic parameters, inhibition, and x-ray structure in complexes with voriconazole and the experimental inhibitor (R)-N-(1-(2,4-dichlorophenyl)-2-(1H-imidazol-1-yl)ethyl)-4-(5-phenyl-1,3,4-oxadiazol-2-yl)benzamide (VNI). The enzyme demethylated its natural substrate eburicol and the plant CYP51 substrate obtusifoliol at steady-state rates of 17 and 16 min(-1), respectively, but did not metabolize lanosterol, and the topical antifungal drug miconazole was the strongest inhibitor that we identified. The x-ray crystal structures displayed high overall similarity of A. fumigatus CYP51B to CYP51 orthologs from other biological kingdoms but revealed phylum-specific differences relevant to enzyme catalysis and inhibition. The complex with voriconazole provides an explanation for the potency of this relatively small molecule, whereas the complex with VNI outlines a direction for further enhancement of the efficiency of this new inhibitory scaffold to treat humans afflicted with filamentous fungal infections.
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Affiliation(s)
- Tatiana Y Hargrove
- From the Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232
| | - Zdzislaw Wawrzak
- the Synchrotron Research Center, Life Science Collaborative Access Team, Northwestern University, Argonne, Illinois 60439
| | - David C Lamb
- Swansea University, Swansea, Wales SA2 8PP, United Kingdom, and
| | - F Peter Guengerich
- From the Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232
| | - Galina I Lepesheva
- From the Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, the Center for Structural Biology, Vanderbilt University, Nashville, Tennessee 37232
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Lepesheva GI, Hargrove TY, Rachakonda G, Wawrzak Z, Pomel S, Cojean S, Nde PN, Nes WD, Locuson CW, Calcutt MW, Waterman MR, Daniels JS, Loiseau PM, Villalta F. VFV as a New Effective CYP51 Structure-Derived Drug Candidate for Chagas Disease and Visceral Leishmaniasis. J Infect Dis 2015; 212:1439-48. [DOI: 10.1093/infdis/jiv228] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Accepted: 04/08/2015] [Indexed: 11/14/2022] Open
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Targeting Ergosterol biosynthesis in Leishmania donovani: essentiality of sterol 14 alpha-demethylase. PLoS Negl Trop Dis 2015; 9:e0003588. [PMID: 25768284 PMCID: PMC4359151 DOI: 10.1371/journal.pntd.0003588] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Accepted: 02/03/2015] [Indexed: 01/14/2023] Open
Abstract
Leishmania protozoan parasites (Trypanosomatidae family) are the causative agents of cutaneous, mucocutaneous and visceral leishmaniasis worldwide. While these diseases are associated with significant morbidity and mortality, there are few adequate treatments available. Sterol 14alpha-demethylase (CYP51) in the parasite sterol biosynthesis pathway has been the focus of considerable interest as a novel drug target in Leishmania. However, its essentiality in Leishmania donovani has yet to be determined. Here, we use a dual biological and pharmacological approach to demonstrate that CYP51 is indispensable in L. donovani. We show via a facilitated knockout approach that chromosomal CYP51 genes can only be knocked out in the presence of episomal complementation and that this episome cannot be lost from the parasite even under negative selection. In addition, we treated wild-type L. donovani and CYP51-deficient strains with 4-aminopyridyl-based inhibitors designed specifically for Trypanosoma cruzi CYP51. While potency was lower than in T. cruzi, these inhibitors had increased efficacy in parasites lacking a CYP51 allele compared to complemented parasites, indicating inhibition of parasite growth via a CYP51-specific mechanism and confirming essentiality of CYP51 in L. donovani. Overall, these results provide support for further development of CYP51 inhibitors for the treatment of visceral leishmaniasis. Visceral leishmaniasis is the second most lethal parasitic infection after malaria. Other forms of leishmaniasis also cause significant morbidity. However, there are few treatments available, and many cause severe side effects or are associated with the development of resistance. A key difference between mammalian cells and Leishmania parasites is the type of sterol in their membranes: while mammalian cell membranes contain cholesterol, Leishmania parasites use ergosterol. There has therefore been considerable interest in developing inhibitors of sterol biosynthesis pathways to target Leishmania parasites. Sterol 14alpha-demethylase (CYP51) is one of the enzymes in the sterol biosynthesis pathway, and the target of significant drug development research in Leishmania. Here we use a double approach to determine whether this gene is essential in Leishmania donovani, the causative agent of visceral leishmaniasis. We demonstrate via gene knockout and drug targeting approaches that loss or inhibition of CYP51 inhibits L. donovani growth. These results validate CYP51 as a drug target in L. donovani and support further work to develop CYP51-directed therapies for visceral leishmaniasis.
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