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Romeo M, Hafidi Z, Muzzalupo R, Pons R, García MT, Mazzotta E, Pérez L. Antimicrobial and Anesthetic Niosomal Formulations Based on Amino Acid-Derived Surfactants. Molecules 2024; 29:2843. [PMID: 38930908 PMCID: PMC11206639 DOI: 10.3390/molecules29122843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2024] [Revised: 06/04/2024] [Accepted: 06/11/2024] [Indexed: 06/28/2024] Open
Abstract
BACKGROUND This work proposes the development of new vesicular systems based on anesthetic compounds (lidocaine (LID) and capsaicin (CA)) and antimicrobial agents (amino acid-based surfactants from phenylalanine), with a focus on physicochemical characterization and the evaluation of antimicrobial and cytotoxic properties. METHOD Phenylalanine surfactants were characterized via high-performance liquid chromatography (HPLC) and nuclear magnetic resonance (NMR). Different niosomal systems based on capsaicin, lidocaine, cationic phenylalanine surfactants, and dipalmitoyl phosphatidylcholine (DPPC) were characterized in terms of size, polydispersion index (PI), zeta potential, and encapsulation efficiency using dynamic light scattering (DLS), transmitted light microscopy (TEM), and small-angle X-ray scattering (SAXS). Furthermore, the interaction of the pure compounds used to prepare the niosomal formulations with DPPC monolayers was determined using a Langmuir balance. The antibacterial activity of the vesicular systems and their biocompatibility were evaluated, and molecular docking studies were carried out to obtain information about the mechanism by which these compounds interact with bacteria. RESULTS The stability and reduced size of the analyzed niosomal formulations demonstrate their potential in pharmaceutical applications. The nanosystems exhibit promising antimicrobial activity, marking a significant advancement in pharmaceutical delivery systems with dual therapeutic properties. The biocompatibility of some formulations underscores their viability. CONCLUSIONS The proposed niosomal formulations could constitute an important advance in the pharmaceutical field, offering delivery systems for combined therapies thanks to the pharmacological properties of the individual components.
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Affiliation(s)
- Martina Romeo
- Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, Via P. Bucci, 87036 Arcavacata di Rende, Italy; (M.R.); (R.M.); (E.M.)
| | - Zakaria Hafidi
- Department of Surfactants and Nanobiotechnology, Institute for Advanced Chemistry of Catalonia (IQAC-CSIC), 08034 Barcelona, Spain; (Z.H.); (R.P.); (M.T.G.)
| | - Rita Muzzalupo
- Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, Via P. Bucci, 87036 Arcavacata di Rende, Italy; (M.R.); (R.M.); (E.M.)
| | - Ramon Pons
- Department of Surfactants and Nanobiotechnology, Institute for Advanced Chemistry of Catalonia (IQAC-CSIC), 08034 Barcelona, Spain; (Z.H.); (R.P.); (M.T.G.)
| | - María Teresa García
- Department of Surfactants and Nanobiotechnology, Institute for Advanced Chemistry of Catalonia (IQAC-CSIC), 08034 Barcelona, Spain; (Z.H.); (R.P.); (M.T.G.)
| | - Elisabetta Mazzotta
- Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, Via P. Bucci, 87036 Arcavacata di Rende, Italy; (M.R.); (R.M.); (E.M.)
| | - Lourdes Pérez
- Department of Surfactants and Nanobiotechnology, Institute for Advanced Chemistry of Catalonia (IQAC-CSIC), 08034 Barcelona, Spain; (Z.H.); (R.P.); (M.T.G.)
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Picón DF, Skouta R. Unveiling the Therapeutic Potential of Squalene Synthase: Deciphering Its Biochemical Mechanism, Disease Implications, and Intriguing Ties to Ferroptosis. Cancers (Basel) 2023; 15:3731. [PMID: 37509391 PMCID: PMC10378455 DOI: 10.3390/cancers15143731] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2023] [Revised: 07/12/2023] [Accepted: 07/20/2023] [Indexed: 07/30/2023] Open
Abstract
Squalene synthase (SQS) has emerged as a promising therapeutic target for various diseases, including cancers, owing to its pivotal role in the mevalonate pathway and the antioxidant properties of squalene. Primarily, SQS orchestrates the head-to-head condensation reaction, catalyzing the fusion of two farnesyl pyrophosphate molecules, leading to the formation of squalene, which has been depicted as a highly effective oxygen-scavenging agent in in vitro studies. Recent studies have depicted this isoprenoid as a protective layer against ferroptosis due to its potential regulation of lipid peroxidation, as well as its protection against oxidative damage. Therefore, beyond its fundamental function, recent investigations have unveiled additional roles for SQS as a regulator of lipid peroxidation and programmed cell death pathways, such as ferroptosis-a type of cell death characterized by elevated levels of lipid peroxide, one of the forms of reactive oxygen species (ROS), and intracellular iron concentration. Notably, thorough explorations have shed light on the distinctive features that set SQS apart from other members within the isoprenoid synthase superfamily. Its unique biochemical structure, intricately intertwined with its reaction mechanism, has garnered significant attention. Moreover, considerable evidence substantiates the significance of SQS in various disease contexts, and its intriguing association with ferroptosis and lipid peroxidation. The objective of this report is to analyze the existing literature comprehensively, corroborating these findings, and provide an up-to-date perspective on the current understanding of SQS as a prospective therapeutic target, as well as its intricate relationship with ferroptosis. This review aims to consolidate the knowledge surrounding SQS, thereby contributing to the broader comprehension of its potential implications in disease management and therapeutic interventions.
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Affiliation(s)
| | - Rachid Skouta
- Department of Biology, University of Massachusetts, Amherst, MA 01003, USA
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3
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Visbal G, Justo RMS, dos Santos da Silva e Miranda G, Teixeira de Macedo Silva S, de Souza W, Rodrigues JCF, Navarro M. Zinc(II)-Sterol Hydrazone Complex as a Potent Anti-Leishmania Agent: Synthesis, Characterization, and Insight into Its Mechanism of Antiparasitic Action. Pharmaceutics 2023; 15:pharmaceutics15041113. [PMID: 37111599 PMCID: PMC10142724 DOI: 10.3390/pharmaceutics15041113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 03/26/2023] [Accepted: 03/28/2023] [Indexed: 04/03/2023] Open
Abstract
Searching for new alternatives for treating leishmaniasis, we present the synthesis, characterization, and biological evaluation against Leishmania amazonensis of the new ZnCl2(H3)2 complex. H3 is 22-hydrazone-imidazoline-2-yl-chol-5-ene-3β-ol, a well-known bioactive molecule functioning as a sterol Δ24-sterol methyl transferase (24-SMT) inhibitor. The ZnCl2(H3)2 complex was characterized by infrared, UV-vis, molar conductance measurements, elemental analysis, mass spectrometry, and NMR experiments. The biological results showed that the free ligand H3 and ZnCl2(H3)2 significantly inhibited the growth of promastigotes and intracellular amastigotes. The IC50 values found for H3 and ZnCl2(H3)2 were 5.2 µM and 2.5 µM for promastigotes, and 543 nM and 32 nM for intracellular amastigotes, respectively. Thus, the ZnCl2(H3)2 complex proved to be seventeen times more potent than the free ligand H3 against the intracellular amastigote, the clinically relevant stage. Furthermore, cytotoxicity assays and determination of selectivity index (SI) revealed that ZnCl2(H3)2 (CC50 = 5 μΜ, SI = 156) is more selective than H3 (CC50 = 10 μΜ, SI = 20). Furthermore, as H3 is a specific inhibitor of the 24-SMT, free sterol analysis was performed. The results showed that H3 was not only able to induce depletion of endogenous parasite sterols (episterol and 5-dehydroepisterol) and their replacement by 24-desalkyl sterols (cholesta-5,7,24-trien-3β-ol and cholesta-7,24-dien-3β-ol) but also its zinc derivative resulting in a loss of cell viability. Using electron microscopy, studies on the fine ultrastructure of the parasites showed significant differences between the control cells and parasites treated with H3 and ZnCl2(H3)2. The inhibitors induced membrane wrinkle, mitochondrial injury, and abnormal chromatin condensation changes that are more intense in the cells treated with ZnCl2(H3)2.
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4
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Malwal S, Shang N, Liu W, Li X, Zhang L, Chen CC, Guo RT, Oldfield E. A Structural and Bioinformatics Investigation of a Fungal Squalene Synthase and Comparisons with Other Membrane Proteins. ACS OMEGA 2022; 7:22601-22612. [PMID: 35811857 PMCID: PMC9260892 DOI: 10.1021/acsomega.2c01924] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Accepted: 06/03/2022] [Indexed: 06/15/2023]
Abstract
There is interest in the development of drugs to treat fungal infections due to the increasing threat of drug resistance, and here, we report the first crystallographic structure of the catalytic domain of a fungal squalene synthase (SQS), Aspergillus flavus SQS (AfSQS), a potential drug target, together with a bioinformatics study of fungal, human, and protozoal SQSs. Our X-ray results show strong structural similarities between the catalytic domains in these proteins, but, remarkably, using bioinformatics, we find that there is also a large, highly polar helix in the fungal proteins that connects the catalytic and membrane-anchoring transmembrane domains. This polar helix is absent in squalene synthases from all other lifeforms. We show that the transmembrane domain in AfSQS and in other SQSs, stannin, and steryl sulfatase, have very similar properties (% polar residues, hydrophobicity, and hydrophobic moment) to those found in the "penultimate" C-terminal helical domain in squalene epoxidase, while the final C-terminal domain in squalene epoxidase is more polar and may be monotopic. We also propose structural models for full-length AfSQS based on the bioinformatics results as well as a deep learning program that indicate that the C-terminus region may also be membrane surface-associated. Taken together, our results are of general interest given the unique nature of the polar helical domain in fungi that may be involved in protein-protein interactions as well as being a future target for antifungals.
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Affiliation(s)
- Satish
R. Malwal
- Department
of Chemistry, University of Illinois at
Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Na Shang
- Industrial
Enzymes National Engineering Laboratory, Tianjin Institute of Industrial Biotechnology, Chinese Academy of
Sciences, Tianjin 300308, China
| | - Weidong Liu
- Industrial
Enzymes National Engineering Laboratory, Tianjin Institute of Industrial Biotechnology, Chinese Academy of
Sciences, Tianjin 300308, China
| | - Xian Li
- State
Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Collaborative
Innovation Center for Green Transformation of Bio-resources, Hubei
Key Laboratory of Industrial Biotechnology, School of Life Sciences, Hubei University, Wuhan 430062, China
| | - Lilan Zhang
- State
Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Collaborative
Innovation Center for Green Transformation of Bio-resources, Hubei
Key Laboratory of Industrial Biotechnology, School of Life Sciences, Hubei University, Wuhan 430062, China
| | - Chun-Chi Chen
- State
Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Collaborative
Innovation Center for Green Transformation of Bio-resources, Hubei
Key Laboratory of Industrial Biotechnology, School of Life Sciences, Hubei University, Wuhan 430062, China
| | - Rey-Ting Guo
- State
Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Collaborative
Innovation Center for Green Transformation of Bio-resources, Hubei
Key Laboratory of Industrial Biotechnology, School of Life Sciences, Hubei University, Wuhan 430062, China
| | - Eric Oldfield
- Department
of Chemistry, University of Illinois at
Urbana-Champaign, Urbana, Illinois 61801, United States
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Hafidi Z, Yakkou L, Guouguaou FE, Amghar S, Achouri ME. Aminoalcohol-based surfactants (N-(hydroxyalkyl)-N, N- dimethyl N-alkylammonium bromide): evaluation of antibacterial activity and molecular docking studies against dehydrosqualene synthase enzyme (CrtM). J DISPER SCI TECHNOL 2019. [DOI: 10.1080/01932691.2019.1700134] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Zakaria Hafidi
- Laboratoire de physico-chimie des matériaux inorganiques et organiques, Centre des Sciences des Matériaux, Ecole Normale Supérieure-Rabat, Mohammed V University, Rabat, Morocco
| | - Lamia Yakkou
- Research Team: « Lumbricidae, Improving Soil Productivity and Environment » (LAPSE). Centre « Eau, Ressources Naturelles, Environnement et Développement Durable (CERN2D) », Ecole Normale Supérieure- University Mohamed V, Rabat, Morocco
| | - Fatima-Ezzahra Guouguaou
- Laboratoire de physico-chimie des matériaux inorganiques et organiques, Centre des Sciences des Matériaux, Ecole Normale Supérieure-Rabat, Mohammed V University, Rabat, Morocco
| | - Souad Amghar
- Research Team: « Lumbricidae, Improving Soil Productivity and Environment » (LAPSE). Centre « Eau, Ressources Naturelles, Environnement et Développement Durable (CERN2D) », Ecole Normale Supérieure- University Mohamed V, Rabat, Morocco
| | - Mohammed El Achouri
- Laboratoire de physico-chimie des matériaux inorganiques et organiques, Centre des Sciences des Matériaux, Ecole Normale Supérieure-Rabat, Mohammed V University, Rabat, Morocco
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Zhang T, Yuan D, Xie J, Lei Y, Li J, Fang G, Tian L, Liu J, Cui Y, Zhang M, Xiao Y, Xu Y, Zhang J, Zhu M, Zhan S, Li S. Evolution of the cholesterol biosynthesis pathway in animals. Mol Biol Evol 2019; 36:2548-2556. [PMID: 31397867 DOI: 10.1093/molbev/msz167] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 06/10/2019] [Accepted: 07/03/2019] [Indexed: 01/11/2023] Open
Abstract
Cholesterol plays essential roles in animal development and disease progression. Here, we characterize the evolutionary pattern of the canonical cholesterol biosynthesis pathway (CBP) in the animal kingdom using both genome-wide analyses and functional experiments. CBP genes in the basal metazoans were inherited from their last common eukaryotic ancestor and evolutionarily conserved for cholesterol biosynthesis. The genomes of both the basal metazoans and deuterostomes retain almost the full set of CBP genes, while Cnidaria and many protostomes have independently experienced multiple massive losses of CBP genes that might be due to the geologic events during the Ediacaran period, such as the appearance of an exogenous sterol supply and the frequent perturbation of ocean oxygenation. Meanwhile, the indispensable utilization processes of cholesterol potentially strengthened the maintenance of the complete set of CBP genes in vertebrates. These results strengthen both biotic and abiotic roles in the macroevolution of a biosynthesis pathway in animals.
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Affiliation(s)
- Tingting Zhang
- Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou, China.,Research Institute of Applied Biology, Shanxi University, Taiyuan, China.,CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Dongwei Yuan
- Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou, China.,CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Jun Xie
- State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Sciences, Fudan University, Shanghai, China
| | - Yongxing Lei
- University of Chinese Academy of Sciences, Beijing, China.,Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Jianguo Li
- Institute of Biomedical Sciences, Shanxi University, Taiyuan, China
| | - Gangqi Fang
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Ling Tian
- Guangdong Provincial Key Laboratory of Agro-animal Genomics and Molecular Breeding/Guangdong Provincial Sericulture and Mulberry Engineering Research Center, College of Animal Science, South China Agricultural University, Guangzhou, China
| | - Jiacheng Liu
- University of Chinese Academy of Sciences, Beijing, China.,The State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Innovation Center for Cell Signaling Network, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai, China
| | - Yingying Cui
- Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou, China
| | - Min Zhang
- Research Institute of Applied Biology, Shanxi University, Taiyuan, China
| | - Youli Xiao
- Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Yongzhen Xu
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Jianzhen Zhang
- Research Institute of Applied Biology, Shanxi University, Taiyuan, China
| | - Maoyan Zhu
- State Key Laboratory of Paleobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing, China
| | - Shuai Zhan
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Sheng Li
- Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou, China
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Quantitative Structure-Activity Relationships for Structurally Diverse Chemotypes Having Anti- Trypanosoma cruzi Activity. Int J Mol Sci 2019; 20:ijms20112801. [PMID: 31181717 PMCID: PMC6600563 DOI: 10.3390/ijms20112801] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Revised: 05/17/2019] [Accepted: 05/17/2019] [Indexed: 12/17/2022] Open
Abstract
Small-molecule compounds that have promising activity against macromolecular targets from Trypanosoma cruzi occasionally fail when tested in whole-cell phenotypic assays. This outcome can be attributed to many factors, including inadequate physicochemical and pharmacokinetic properties. Unsuitable physicochemical profiles usually result in molecules with a poor ability to cross cell membranes. Quantitative structure-activity relationship (QSAR) analysis is a valuable approach to the investigation of how physicochemical characteristics affect biological activity. In this study, artificial neural networks (ANNs) and kernel-based partial least squares regression (KPLS) were developed using anti-T. cruzi activity data for broadly diverse chemotypes. The models exhibited a good predictive ability for the test set compounds, yielding q2 values of 0.81 and 0.84 for the ANN and KPLS models, respectively. The results of this investigation highlighted privileged molecular scaffolds and the optimum physicochemical space associated with high anti-T. cruzi activity, which provided important guidelines for the design of novel trypanocidal agents having drug-like properties.
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8
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Duschak VG. Major Kinds of Drug Targets in Chagas Disease or American Trypanosomiasis. Curr Drug Targets 2019; 20:1203-1216. [PMID: 31020939 DOI: 10.2174/1389450120666190423160804] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 04/12/2019] [Accepted: 04/12/2019] [Indexed: 11/22/2022]
Abstract
American Trypanosomiasis, a parasitic infection commonly named Chagas disease, affects millions of people all over Latin American countries. Presently, the World Health Organization (WHO) predicts that the number of international infected individuals extends to 7 to 8 million, assuming that more than 10,000 deaths occur annually. The transmission of the etiologic agent, Trypanosoma cruzi, through people migrating to non-endemic world nations makes it an emergent disease. The best promising targets for trypanocidal drugs may be classified into three main groups: Group I includes the main molecular targets that are considered among specific enzymes involved in the essential processes for parasite survival, principally Cruzipain, the major antigenic parasite cysteine proteinase. Group II involves biological pathways and their key specific enzymes, such as Sterol biosynthesis pathway, among others, specific antioxidant defense mechanisms, and bioenergetics ones. Group III includes the atypical organelles /structures present in the parasite relevant clinical forms, which are absent or considerably different from those present in mammals and biological processes related to them. These can be considered potential targets to develop drugs with extra effectiveness and fewer secondary effects than the currently used therapeutics. An improved distinction between the host and the parasite targets will help fight against this neglected disease.
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Affiliation(s)
- Vilma G Duschak
- National Council of Scientific and Technical Reasearch (CONICET) Researcher, Area of Protein Biochemistry and Parasite Glycobiology, Research Department, National Institute of Parasitology (INP), "Dr. Mario Fatala Chaben", ANLIS-Malbran, National Health Secretary, Av. Paseo Colon 568, Lab 506, Ciudad Autonoma de Buenos Aires (1063), Buenos Aires, Argentina
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9
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Abdelmagid WM, Adak T, Freeman JO, Tanner ME. Studies with Guanidinium- and Amidinium-Based Inhibitors Suggest Minimal Stabilization of Allylic Carbocation Intermediates by Dehydrosqualene and Squalene Synthases. Biochemistry 2018; 57:5591-5601. [PMID: 30179505 DOI: 10.1021/acs.biochem.8b00731] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Dehydrosqualene and squalene synthases catalyze the redox neutral and the reductive, head-to-head dimerization of farnesyl diphosphate, respectively. In each case, the reaction is thought to proceed via an initial dissociation of farnesyl diphosphate to form an allylic carbocation-pyrophosphate ion pair. This work describes the synthesis and testing of inhibitors in which a guanidinium or amidinium moiety is flanked by a phosphonylphosphinate group and a hydrocarbon tail. These functional groups bear a planar, delocalized, positive charge and therefore should act as excellent mimics of an allylic carbocation. An inhibitor bearing a neutral urea moiety was also prepared as a control. The positively charged inhibitors acted as competitive inhibitors against Staphylococcus aureus dehydrosqualene synthase with Ki values in the low micromolar range. Surprisingly, the neutral urea inhibitor was the most potent of the three. Similar trends were seen with the first half reaction of human squalene synthase. One interpretation of these results is that the active sites of these enzymes do not directly stabilize the allylic carbocation via electrostatic or π-cation interactions. Instead, it is likely that the enzymes use tight binding to the pyrophosphate and lipid moieties to promote catalysis and that electrostatic stabilization of the carbocation is provided by the bound pyrophosphate product. An alternate possibility is that these inhibitors cannot bind to the "ionization FPP-binding site" of the enzyme and only bind to the "nonionizing FPP-binding site". In either case, all reported attempts to generate potent inhibitors with cationic FPP analogues have been unsuccessful to date.
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Affiliation(s)
- Walid M Abdelmagid
- Department of Chemistry , University of British Columbia , Vancouver , British Columbia V6T 1Z1 , Canada
| | - Taniya Adak
- Department of Chemistry , University of British Columbia , Vancouver , British Columbia V6T 1Z1 , Canada
| | - Jon O Freeman
- Department of Chemistry , Pacific Lutheran University , Tacoma , Washington 98447 , United States
| | - Martin E Tanner
- Department of Chemistry , University of British Columbia , Vancouver , British Columbia V6T 1Z1 , Canada
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10
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Chao MN, Storey M, Li C, Rodríguez MG, Di Salvo F, Szajnman SH, Moreno SN, Docampo R, Rodriguez JB. Selenium-containing analogues of WC-9 are extremely potent inhibitors of Trypanosoma cruzi proliferation. Bioorg Med Chem 2017; 25:6435-6449. [DOI: 10.1016/j.bmc.2017.10.016] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Revised: 10/06/2017] [Accepted: 10/15/2017] [Indexed: 12/21/2022]
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11
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Chao MN, Li C, Storey M, Falcone BN, Szajnman SH, Bonesi SM, Docampo R, Moreno SNJ, Rodriguez JB. Activity of Fluorine-Containing Analogues of WC-9 and Structurally Related Analogues against Two Intracellular Parasites: Trypanosoma cruzi and Toxoplasma gondii. ChemMedChem 2016; 11:2690-2702. [PMID: 27886451 PMCID: PMC5200956 DOI: 10.1002/cmdc.201600505] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Revised: 10/20/2016] [Indexed: 11/10/2022]
Abstract
Two obligate intracellular parasites, Trypanosoma cruzi, the agent of Chagas disease, and Toxoplasma gondii, an agent of toxoplasmosis, upregulate the mevalonate pathway of their host cells upon infection, which suggests that this host pathway could be a potential drug target. In this work, a number of compounds structurally related to WC-9 (4-phenoxyphenoxyethyl thiocyanate), a known squalene synthase inhibitor, were designed, synthesized, and evaluated for their effect on T. cruzi and T. gondii growth in tissue culture cells. Two fluorine-containing derivatives, the 3-(3-fluorophenoxy)- and 3-(4-fluorophenoxy)phenoxyethyl thiocyanates, exhibited half-maximal effective concentration (EC50 ) values of 1.6 and 4.9 μm, respectively, against tachyzoites of T. gondii, whereas they showed similar potency to WC-9 against intracellular T. cruzi (EC50 values of 5.4 and 5.7 μm, respectively). In addition, 2-[3- (phenoxy)phenoxyethylthio]ethyl-1,1-bisphosphonate, which is a hybrid inhibitor containing 3-phenoxyphenoxy and bisphosphonate groups, has activity against T. gondii proliferation at sub-micromolar levels (EC50 =0.7 μm), which suggests a combined inhibitory effect of the two functional groups.
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Affiliation(s)
- María N. Chao
- M. N. Chao, Dr. B. N. Falcone, Dr. S. H. Szajnman, Prof. Dr. J. B. Rodriguez, Departamento de Química Orgánica and UMYMFOR (CONICET–FCEyN), Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Pabellón 2, Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina
| | - Catherine Li
- C. Li, M. Storey, Prof. Dr. R. Docampo, Prof. Dr. S. N. J. Moreno, Center for Tropical and Emerging Global Diseases and Department of Cellular Biology, University of Georgia, Athens, Georgia, 30602, USA
| | - Melissa Storey
- C. Li, M. Storey, Prof. Dr. R. Docampo, Prof. Dr. S. N. J. Moreno, Center for Tropical and Emerging Global Diseases and Department of Cellular Biology, University of Georgia, Athens, Georgia, 30602, USA
| | - Bruno N. Falcone
- M. N. Chao, Dr. B. N. Falcone, Dr. S. H. Szajnman, Prof. Dr. J. B. Rodriguez, Departamento de Química Orgánica and UMYMFOR (CONICET–FCEyN), Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Pabellón 2, Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina
| | - Sergio H. Szajnman
- M. N. Chao, Dr. B. N. Falcone, Dr. S. H. Szajnman, Prof. Dr. J. B. Rodriguez, Departamento de Química Orgánica and UMYMFOR (CONICET–FCEyN), Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Pabellón 2, Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina
| | - Sergio M. Bonesi
- Prof. Dr. S. M. Bonesi, Departamento de Química Orgánica and CIHIDECAR (CONICET–FCEyN), Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Pabellón 2, Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina
| | - Roberto Docampo
- C. Li, M. Storey, Prof. Dr. R. Docampo, Prof. Dr. S. N. J. Moreno, Center for Tropical and Emerging Global Diseases and Department of Cellular Biology, University of Georgia, Athens, Georgia, 30602, USA
| | - Silvia N. J. Moreno
- C. Li, M. Storey, Prof. Dr. R. Docampo, Prof. Dr. S. N. J. Moreno, Center for Tropical and Emerging Global Diseases and Department of Cellular Biology, University of Georgia, Athens, Georgia, 30602, USA
| | - Juan B. Rodriguez
- M. N. Chao, Dr. B. N. Falcone, Dr. S. H. Szajnman, Prof. Dr. J. B. Rodriguez, Departamento de Química Orgánica and UMYMFOR (CONICET–FCEyN), Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Pabellón 2, Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina
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12
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Shiuan D, Lin HK, Chen YH, Chang DK, Huang KJ, Farh L. Exploration of Peptide Inhibitors of Human Squalene Synthase through Molecular Modeling and Phage Display Technique. Appl Biochem Biotechnol 2015; 178:312-23. [PMID: 26438313 DOI: 10.1007/s12010-015-1873-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Accepted: 09/24/2015] [Indexed: 11/29/2022]
Abstract
Many studies have demonstrated the role of elevated levels of serum cholesterol in the pathogenesis of atherosclerosis and coronary heart disease. Various drugs targeting the key enzymes involved in the cholesterol biosynthesis pathway have been investigated for the treatment of hypercholesterolemia. Human squalene synthase has been one of the most important targets for therapeutic intervention. In the present study, we used the recombinant human squalene synthase as the lure for screening the peptide inhibitors from phage-displayed random peptide library. The tightly bound phages and their derived peptides were further evaluated based on their potential binding capabilities, molecular modeling characteristics and predicted absorption, distribution, metabolism, excretion, toxicity (ADMET) properties. Several hexa-peptides and tetra-peptides were finally synthesized to assay their inhibitory effects toward the recombinant human squalene synthase. The results demonstrated that the hexa-peptide FTACNW and tetra-peptide VACL can inhibit human squalene synthase effectively (with IC50 values near 100 μM) and may have potential to develop further as future hypocholesterolemia agents.
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Affiliation(s)
- David Shiuan
- Department of Life Science and Institute of Biotechnology, National Dong Hwa University, Hualien, Taiwan, 974, Republic of China.
| | - Hwan-Kang Lin
- Department of Life Science and Institute of Biotechnology, National Dong Hwa University, Hualien, Taiwan, 974, Republic of China
| | - Yue-Hao Chen
- Department of Life Science and Institute of Biotechnology, National Dong Hwa University, Hualien, Taiwan, 974, Republic of China
| | - Ding-Kwo Chang
- Institute of Chemistry, Academia Sinica, Taipei, Taiwan, 115, Republic of China
| | - Kao-Jean Huang
- Development Center for Biotechnology, Taipei, Taiwan, 221, Republic of China
| | - Lynn Farh
- Department of Applied Chemistry, National Pingtung University, Pingtung, Taiwan, 900, Republic of China
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Directed optimization of a newly identified squalene synthase from Mortierella alpine based on sequence truncation and site-directed mutagenesis. ACTA ACUST UNITED AC 2015; 42:1341-52. [DOI: 10.1007/s10295-015-1668-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Accepted: 07/28/2015] [Indexed: 12/16/2022]
Abstract
Abstract
Terpenoids, a class of isoprenoids usually isolated from plants, are always used as commercial flavor and anticancer drugs. As a key precursor for triterpenes and sterols, biosynthesis of squalene (SQ) can be catalyzed by squalene synthase (SQS) from two farnesyl diphosphate molecules. In this work, the key SQS gene involved in sterols synthesis by Mortierella alpine, an industrial strain often used to produce unsaturated fatty acid such as γ-linolenic acid and arachidonic acid, was identified and characterized. Bioinformatic analysis indicated that MaSQS contained 416 amino acid residues involved in four highly conserved regions. Phylogenetic analysis revealed the closest relationship of MaSQS with Ganoderma lucidum and Aspergillus, which also belonged to the member of the fungus. Subsequently, the recombinant protein was expressed in Escherichia coli BL21(DE3) and detected by SDS-PAGE. To improve the expression and solubility of protein, 17 or 27 amino acids in the C-terminal were deleted. In vitro activity investigation based on gas chromatography–mass spectrometry revealed that both the truncated enzymes could functionally catalyze the reaction from FPP to SQ and the enzymatic activity was optimal at 37 °C, pH 7.2. Moreover, based on the site-directed mutagenesis, the mutant enzyme mMaSQSΔC17 (E186K) displayed a 3.4-fold improvement in catalytic efficiency (k cat/K m) compared to the control. It was the first report of characterization and modification of SQS from M. alpine, which facilitated the investigation of isoprenoid biosynthesis in the fungus. The engineered mMaSQSΔC17 (E186K) can be a potential candidate of the terpenes and steroids synthesis employed for synthetic biology.
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Abstract
We tested the antituberculosis drug SQ109, which is currently in advanced clinical trials for the treatment of drug-susceptible and drug-resistant tuberculosis, for its in vitro activity against the trypanosomatid parasite Trypanosoma cruzi, the causative agent of Chagas disease. SQ109 was found to be a potent inhibitor of the trypomastigote form of the parasite, with a 50% inhibitory concentration (IC50) for cell killing of 50 ± 8 nM, but it had little effect (50% effective concentration [EC50], ∼80 μM) in a red blood cell hemolysis assay. It also inhibited extracellular epimastigotes (IC50, 4.6 ± 1 μM) and the clinically relevant intracellular amastigotes (IC50, ∼0.5 to 1 μM), with a selectivity index of ∼10 to 20. SQ109 caused major ultrastructural changes in all three life cycle forms, as observed by light microscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). It rapidly collapsed the inner mitochondrial membrane potential (Δψm) in succinate-energized mitochondria, acting in the same manner as the uncoupler FCCP [carbonyl cyanide 4-(trifluoromethoxy)phenylhydrazone], and it caused the alkalinization of internal acidic compartments, effects that are likely to make major contributions to its mechanism of action. The compound also had activity against squalene synthase, binding to its active site; it inhibited sterol side-chain reduction and, in the amastigote assay, acted synergistically with the antifungal drug posaconazole, with a fractional inhibitory concentration index (FICI) of 0.48, but these effects are unlikely to account for the rapid effects seen on cell morphology and cell killing. SQ109 thus most likely acts, at least in part, by collapsing Δψ/ΔpH, one of the major mechanisms demonstrated previously for its action against Mycobacterium tuberculosis. Overall, the results suggest that SQ109, which is currently in advanced clinical trials for the treatment of drug-susceptible and drug-resistant tuberculosis, may also have potential as a drug lead against Chagas disease.
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Ohtake K, Saito N, Shibuya S, Kobayashi W, Amano R, Hirai T, Sasaki S, Nakano C, Hoshino T. Biochemical characterization of the water-soluble squalene synthase fromMethylococcus capsulatusand the functional analyses of its two DXXD(E)D motifs and the highly conserved aromatic amino acid residues. FEBS J 2014; 281:5479-97. [DOI: 10.1111/febs.13090] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Revised: 09/12/2014] [Accepted: 09/30/2014] [Indexed: 11/27/2022]
Affiliation(s)
- Kana Ohtake
- Department of Applied Biological Chemistry; Faculty of Agriculture and Graduate School of Science and Technology; Niigata University; Japan
| | - Naoki Saito
- Department of Applied Biological Chemistry; Faculty of Agriculture and Graduate School of Science and Technology; Niigata University; Japan
| | - Satoshi Shibuya
- Department of Applied Biological Chemistry; Faculty of Agriculture and Graduate School of Science and Technology; Niigata University; Japan
| | - Wakako Kobayashi
- Department of Applied Biological Chemistry; Faculty of Agriculture and Graduate School of Science and Technology; Niigata University; Japan
| | - Ryosuke Amano
- Department of Applied Biological Chemistry; Faculty of Agriculture and Graduate School of Science and Technology; Niigata University; Japan
| | - Takumi Hirai
- Department of Applied Biological Chemistry; Faculty of Agriculture and Graduate School of Science and Technology; Niigata University; Japan
| | - Shinji Sasaki
- Department of Applied Biological Chemistry; Faculty of Agriculture and Graduate School of Science and Technology; Niigata University; Japan
| | - Chiaki Nakano
- Department of Applied Biological Chemistry; Faculty of Agriculture and Graduate School of Science and Technology; Niigata University; Japan
| | - Tsutomu Hoshino
- Department of Applied Biological Chemistry; Faculty of Agriculture and Graduate School of Science and Technology; Niigata University; Japan
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Genetic profiling of the isoprenoid and sterol biosynthesis pathway genes of Trypanosoma cruzi. PLoS One 2014; 9:e96762. [PMID: 24828104 PMCID: PMC4020770 DOI: 10.1371/journal.pone.0096762] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Accepted: 04/04/2014] [Indexed: 12/02/2022] Open
Abstract
In Trypanosoma cruzi the isoprenoid and sterol biosynthesis pathways are validated targets for chemotherapeutic intervention. In this work we present a study of the genetic diversity observed in genes from these pathways. Using a number of bioinformatic strategies, we first identified genes that were missing and/or were truncated in the T. cruzi genome. Based on this analysis we obtained the complete sequence of the ortholog of the yeast ERG26 gene and identified a non-orthologous homolog of the yeast ERG25 gene (sterol methyl oxidase, SMO), and we propose that the orthologs of ERG25 have been lost in trypanosomes (but not in Leishmanias). Next, starting from a set of 16 T. cruzi strains representative of all extant evolutionary lineages, we amplified and sequenced ∼24 Kbp from 22 genes, identifying a total of 975 SNPs or fixed differences, of which 28% represent non-synonymous changes. We observed genes with a density of substitutions ranging from those close to the average (∼2.5/100 bp) to some showing a high number of changes (11.4/100 bp, for the putative lathosterol oxidase gene). All the genes of the pathway are under apparent purifying selection, but genes coding for the sterol C14-demethylase, the HMG-CoA synthase, and the HMG-CoA reductase have the lowest density of missense SNPs in the panel. Other genes (TcPMK, TcSMO-like) have a relatively high density of non-synonymous SNPs (2.5 and 1.9 every 100 bp, respectively). However, none of the non-synonymous changes identified affect a catalytic or ligand binding site residue. A comparative analysis of the corresponding genes from African trypanosomes and Leishmania shows similar levels of apparent selection for each gene. This information will be essential for future drug development studies focused on this pathway.
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Shang N, Li Q, Ko TP, Chan HC, Li J, Zheng Y, Huang CH, Ren F, Chen CC, Zhu Z, Galizzi M, Li ZH, Rodrigues-Poveda CA, Gonzalez-Pacanowska D, Veiga-Santos P, de Carvalho TMU, de Souza W, Urbina JA, Wang AHJ, Docampo R, Li K, Liu YL, Oldfield E, Guo RT. Squalene synthase as a target for Chagas disease therapeutics. PLoS Pathog 2014; 10:e1004114. [PMID: 24789335 PMCID: PMC4006925 DOI: 10.1371/journal.ppat.1004114] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Accepted: 03/28/2014] [Indexed: 12/20/2022] Open
Abstract
Trypanosomatid parasites are the causative agents of many neglected tropical diseases and there is currently considerable interest in targeting endogenous sterol biosynthesis in these organisms as a route to the development of novel anti-infective drugs. Here, we report the first x-ray crystallographic structures of the enzyme squalene synthase (SQS) from a trypanosomatid parasite, Trypanosoma cruzi, the causative agent of Chagas disease. We obtained five structures of T. cruzi SQS and eight structures of human SQS with four classes of inhibitors: the substrate-analog S-thiolo-farnesyl diphosphate, the quinuclidines E5700 and ER119884, several lipophilic bisphosphonates, and the thiocyanate WC-9, with the structures of the two very potent quinuclidines suggesting strategies for selective inhibitor development. We also show that the lipophilic bisphosphonates have low nM activity against T. cruzi and inhibit endogenous sterol biosynthesis and that E5700 acts synergistically with the azole drug, posaconazole. The determination of the structures of trypanosomatid and human SQS enzymes with a diverse set of inhibitors active in cells provides insights into SQS inhibition, of interest in the context of the development of drugs against Chagas disease. Chagas disease is caused by the protozoan parasite Trypanosoma cruzi and affects eight million individuals, primarily in Latin America. Currently there is no cure for chronic T. cruzi infections. Unlike humans, this parasite use a variety of sterols (e.g. ergosterol, 24-ethyl-cholesta-5,7,22-trien-3 beta ol, and its 22-dihydro analogs), rather than cholesterol in their cell membranes, so inhibiting endogenous sterol biosynthesis is an important therapeutic target. Here, we report the first structure of the parasite's squalene synthase, which catalyzes the first committed step in sterol biosynthesis, as well as the structures of a broad range of squalene synthase inhibitors active against the clinically relevant intracellular stages, opening the way to new approaches to treating this neglected tropical disease.
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Affiliation(s)
- Na Shang
- Industrial Enzymes National Engineering Laboratory, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Qian Li
- Industrial Enzymes National Engineering Laboratory, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Tzu-Ping Ko
- Industrial Enzymes National Engineering Laboratory, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Hsiu-Chien Chan
- Industrial Enzymes National Engineering Laboratory, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
| | - Jikun Li
- Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Yingying Zheng
- Industrial Enzymes National Engineering Laboratory, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
| | - Chun-Hsiang Huang
- Industrial Enzymes National Engineering Laboratory, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
| | - Feifei Ren
- Industrial Enzymes National Engineering Laboratory, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
| | - Chun-Chi Chen
- Industrial Enzymes National Engineering Laboratory, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
| | - Zhen Zhu
- Industrial Enzymes National Engineering Laboratory, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
| | - Melina Galizzi
- Center for Tropical and Emerging Global Diseases and Department of Cellular Biology, University of Georgia, Athens, Georgia, United States of America
| | - Zhu-Hong Li
- Center for Tropical and Emerging Global Diseases and Department of Cellular Biology, University of Georgia, Athens, Georgia, United States of America
| | - Carlos A. Rodrigues-Poveda
- Instituto de Parasitología y Biomedicina “Lopez-Neyra”, Consejo Superior de Investigaciones Cientificas, Granada, Spain
| | - Dolores Gonzalez-Pacanowska
- Instituto de Parasitología y Biomedicina “Lopez-Neyra”, Consejo Superior de Investigaciones Cientificas, Granada, Spain
| | - Phercyles Veiga-Santos
- Laboratório de Ultraestrutura Celular Hertha Meyer, CCS, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Ilha do Fundão, Rio de Janeiro, Brazil
- Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagens, Universidade Federal do Rio de Janeiro, Cidade Universitária, Ilha do Fundão, Rio de Janeiro, Brazil
- Diretoria de Programa, Instituto Nacional de Metrologia, Normalização e Qualidade Industrial–INMETRO, Duque de Caxias, Rio de Janeiro, Brazil
| | - Tecia Maria Ulisses de Carvalho
- Laboratório de Ultraestrutura Celular Hertha Meyer, CCS, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Ilha do Fundão, Rio de Janeiro, Brazil
- Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagens, Universidade Federal do Rio de Janeiro, Cidade Universitária, Ilha do Fundão, Rio de Janeiro, Brazil
- Diretoria de Programa, Instituto Nacional de Metrologia, Normalização e Qualidade Industrial–INMETRO, Duque de Caxias, Rio de Janeiro, Brazil
| | - Wanderley de Souza
- Laboratório de Ultraestrutura Celular Hertha Meyer, CCS, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Ilha do Fundão, Rio de Janeiro, Brazil
- Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagens, Universidade Federal do Rio de Janeiro, Cidade Universitária, Ilha do Fundão, Rio de Janeiro, Brazil
- Diretoria de Programa, Instituto Nacional de Metrologia, Normalização e Qualidade Industrial–INMETRO, Duque de Caxias, Rio de Janeiro, Brazil
| | - Julio A. Urbina
- Instituto Venezolano de Investigaciones Cientificas, Caracas, Venezuela
| | | | - Roberto Docampo
- Center for Tropical and Emerging Global Diseases and Department of Cellular Biology, University of Georgia, Athens, Georgia, United States of America
| | - Kai Li
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Yi-Liang Liu
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Eric Oldfield
- Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
- * E-mail: (EO); (RTG)
| | - Rey-Ting Guo
- Industrial Enzymes National Engineering Laboratory, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
- * E-mail: (EO); (RTG)
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18
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Smirlis D, Soares MBP. Selection of molecular targets for drug development against trypanosomatids. Subcell Biochem 2014; 74:43-76. [PMID: 24264240 DOI: 10.1007/978-94-007-7305-9_2] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Trypanosomatid parasites are a group of flagellated protozoa that includes the genera Leishmania and Trypanosoma, which are the causative agents of diseases (leishmaniases, sleeping sickness and Chagas disease) that cause considerable morbidity and mortality, affecting more than 27 million people worldwide. Today no effective vaccines for the prevention of these diseases exist, whereas current chemotherapy is ineffective, mainly due to toxic side effects of current drugs and to the emergence of drug resistance and lack of cost effectiveness. For these reasons, rational drug design and the search of good candidate drug targets is of prime importance. The search for drug targets requires a multidisciplinary approach. To this end, the completion of the genome project of many trypanosomatid species gives a vast amount of new information that can be exploited for the identification of good drug candidates with a prediction of "druggability" and divergence from mammalian host proteins. In addition, an important aspect in the search for good drug targets is the "target identification" and evaluation in a biological pathway, as well as the essentiality of the gene in the mammalian stage of the parasite, which is provided by basic research and genetic and proteomic approaches. In this chapter we will discuss how these bioinformatic tools and experimental evaluations can be integrated for the selection of candidate drug targets, and give examples of metabolic and signaling pathways in the parasitic protozoa that can be exploited for rational drug design.
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19
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Endogenous sterol biosynthesis is important for mitochondrial function and cell morphology in procyclic forms of Trypanosoma brucei. Int J Parasitol 2012; 42:975-89. [PMID: 22964455 DOI: 10.1016/j.ijpara.2012.07.012] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2012] [Revised: 07/19/2012] [Accepted: 07/22/2012] [Indexed: 11/22/2022]
Abstract
Sterol biosynthesis inhibitors are promising entities for the treatment of trypanosomal diseases. Insect forms of Trypanosoma brucei, the causative agent of sleeping sickness, synthesize ergosterol and other 24-alkylated sterols, yet also incorporate cholesterol from the medium. While sterol function has been investigated by pharmacological manipulation of sterol biosynthesis, molecular mechanisms by which endogenous sterols influence cellular processes remain largely unknown in trypanosomes. Here we analyse by RNA interference, the effects of a perturbation of three specific steps of endogenous sterol biosynthesis in order to dissect the role of specific intermediates in proliferation, mitochondrial function and cellular morphology in procyclic cells. A decrease in the levels of squalene synthase and squalene epoxidase resulted in a depletion of cellular sterol intermediates and end products, impaired cell growth and led to aberrant morphologies, DNA fragmentation and a profound modification of mitochondrial structure and function. In contrast, cells deficient in sterol methyl transferase, the enzyme involved in 24-alkylation, exhibited a normal growth phenotype in spite of a complete abolition of the synthesis and content of 24-alkyl sterols. Thus, the data provided indicates that while the depletion of squalene and post-squalene endogenous sterol metabolites results in profound cellular defects, bulk 24-alkyl sterols are not strictly required to support growth in insect forms of T. brucei in vitro.
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20
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Gupta N, Sharma P, Santosh Kumar RJ, Vishwakarma RK, Khan BM. Functional characterization and differential expression studies of squalene synthase from Withania somnifera. Mol Biol Rep 2012; 39:8803-12. [PMID: 22718506 DOI: 10.1007/s11033-012-1743-4] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2011] [Accepted: 06/07/2012] [Indexed: 10/28/2022]
Abstract
Squalene synthase (SQS: EC 2.5.1.21) is a potential branch point regulatory enzyme and represents the first committed step to diverge the carbon flux from the main isoprenoid pathway towards sterol biosynthesis. In the present study, cloning and characterization of Withania somnifera squalene synthase (WsSQS) cDNA was investigated subsequently followed by its heterologous expression and preliminary enzyme activity. Two different types of WsSQS cDNA clones (WsSQS1and WsSQS2) were identified that contained an open reading frames of 1,236 and 1,242 bp encoding polypeptides of 412 and 414 amino acids respectively. Both WsSQS isoforms share 99 % similarity and identity with each other. WsSQS deduced amino acids sequences, when compared with SQS of other plant species, showed maximum similarity and identity with Capsicum annuum followed by Solanum tuberosum and Nicotiana tabacum. To obtain soluble recombinant enzymes, 24 hydrophobic amino acids were deleted from the carboxy terminus and expressed as 6X His-Tag fusion protein in Escherichia coli. Approximately 43 kDa recombinant protein was purified using Ni-NTA affinity chromatography and checked on SDS-PAGE. Preliminary activity of the purified enzymes was determined and the products were analyzed by gas chromatograph-mass spectrometer (GC-MS). Quantitative real-time PCR (qRT-PCR) analysis showed that WsSQS expresses more in young leaves than mature leaves, stem and root.
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Affiliation(s)
- Neha Gupta
- Plant Tissue Culture Division, National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411008, Maharashtra, India
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21
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2-alkylaminoethyl-1,1-bisphosphonic acids are potent inhibitors of the enzymatic activity of Trypanosoma cruzi squalene synthase. Antimicrob Agents Chemother 2012; 56:4483-6. [PMID: 22585217 DOI: 10.1128/aac.00796-12] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
As part of our efforts aimed at searching for new antiparasitic agents, the effect of representative 2-alkylaminoethyl-1,1-bisphosphonic acids on Trypanosoma cruzi squalene synthase (TcSQS) was investigated. These compounds had proven to be potent inhibitors of T. cruzi. This cellular activity had been associated with an inhibition of the enzymatic activity of T. cruzi farnesyl diphosphate synthase. 2-Alkylaminoethyl-1,1-bisphosphonic acids appear to have a dual action, since they also inhibit TcSQS at the nanomolar range.
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22
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Lin FY, Liu YL, Li K, Cao R, Zhu W, Axelson J, Pang R, Oldfield E. Head-to-head prenyl tranferases: anti-infective drug targets. J Med Chem 2012; 55:4367-72. [PMID: 22486710 DOI: 10.1021/jm300208p] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report X-ray crystallographic structures of three inhibitors bound to dehydrosqualene synthase from Staphylococcus aureus: 1 (BPH-651), 2 (WC-9), and 3 (SQ-109). Compound 2 binds to the S2 site with its -SCN group surrounded by four hydrogen bond donors. With 1, we report two structures: in both, the quinuclidine headgroup binds in the allylic (S1) site with the side chain in S2, but in the presence of PPi and Mg(2+), the quinuclidine's cationic center interacts with PPi and three Mg(2+), mimicking a transition state involved in diphosphate ionization. With 3, there are again two structures. In one, the geranyl side chain binds to either S1 or S2 and the adamantane headgroup binds to S1. In the second, the side chain binds to S2 while the headgroup binds to S1. These results provide structural clues for the mechanism and inhibition of the head-to-head prenyl transferases and should aid future drug design.
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Affiliation(s)
- Fu-Yang Lin
- Center for Biophysics and Computational Biology,University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
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23
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Panda T, Basak T, Saraswathi G, Théodore T. Kinetic Mechanisms of Cholesterol Synthesis: A Review. Ind Eng Chem Res 2011. [DOI: 10.1021/ie200073a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | | | | | - Thomas Théodore
- Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai−600 036, India
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24
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25
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Abstract
"Head-to-head" terpene synthases catalyze the first committed steps in sterol and carotenoid biosynthesis: the condensation of two isoprenoid diphosphates to form cyclopropylcarbinyl diphosphates, followed by ring opening. Here, we report the structures of Staphylococcus aureus dehydrosqualene synthase (CrtM) complexed with its reaction intermediate, presqualene diphosphate (PSPP), the dehydrosqualene (DHS) product, as well as a series of inhibitors. The results indicate that, on initial diphosphate loss, the primary carbocation so formed bends down into the interior of the protein to react with C2,3 double bond in the prenyl acceptor to form PSPP, with the lower two-thirds of both PSPP chains occupying essentially the same positions as found in the two farnesyl chains in the substrates. The second-half reaction is then initiated by the PSPP diphosphate returning back to the Mg(2+) cluster for ionization, with the resultant DHS so formed being trapped in a surface pocket. This mechanism is supported by the observation that cationic inhibitors (of interest as antiinfectives) bind with their positive charge located in the same region as the cyclopropyl carbinyl group; that S-thiolo-diphosphates only inhibit when in the allylic site; activity results on 11 mutants show that both DXXXD conserved domains are essential for PSPP ionization; and the observation that head-to-tail isoprenoid synthases as well as terpene cyclases have ionization and alkene-donor sites which spatially overlap those found in CrtM.
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26
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Urbina JA. Specific chemotherapy of Chagas disease: relevance, current limitations and new approaches. Acta Trop 2010; 115:55-68. [PMID: 19900395 DOI: 10.1016/j.actatropica.2009.10.023] [Citation(s) in RCA: 322] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2009] [Revised: 10/22/2009] [Accepted: 10/26/2009] [Indexed: 01/31/2023]
Abstract
A critical review of the development of specific chemotherapeutic approaches for the management of American Trypanosomiasis or Chagas disease is presented, including controversies on the pathogenesis of the disease, the initial efforts that led to the development of currently available drugs (nifurtimox and benznidazole), limitations of these therapies and novel approaches for the development of anti-Trypanosoma cruzi drugs, based on our growing understanding of the biology of this parasite. Among the later, the most promising approaches are ergosterol biosynthesis inhibitors such as posaconazole and ravuconazole, poised to enter clinical trials for chronic Chagas disease in the short term; inhibitors of cruzipain, the main cysteine protease of T. cruzi, essential for its survival and proliferation in vitro and in vivo; bisphosphonates, metabolic stable pyrophosphate analogs that have trypanocidal activity through the inhibition of the parasite's farnesyl-pyrophosphate synthase or hexokinase; inhibitors of trypanothione synthesis and redox metabolism and inhibitors of hypoxanthine-guanine phosphoribosyl-transferase, an essential enzyme for purine salvage in T. cruzi and related organisms. Finally, the economic and political challenges faced by development of drugs for the treatment of neglected tropical diseases, which afflict almost exclusively poor populations in developing countries, are analyzed and recent potential solutions for this conundrum are discussed.
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Cloning and characterization of squalene synthase gene from Fusarium fujikuroi (Saw.) Wr. J Ind Microbiol Biotechnol 2010; 37:1171-82. [DOI: 10.1007/s10295-010-0764-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2010] [Accepted: 06/07/2010] [Indexed: 10/19/2022]
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Cerecetto H, González M. Synthetic Medicinal Chemistry in Chagas' Disease: Compounds at The Final Stage of "Hit-To-Lead" Phase. Pharmaceuticals (Basel) 2010; 3:810-838. [PMID: 27713281 PMCID: PMC4034012 DOI: 10.3390/ph3040810] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2010] [Revised: 03/15/2010] [Accepted: 03/19/2010] [Indexed: 11/16/2022] Open
Abstract
Chagas' disease, or American trypanosomosiasis, has been the most relevant illness produced by protozoa in Latin America. Synthetic medicinal chemistry efforts have provided an extensive number of chemodiverse hits at the "active-to-hit" stage. However, only a more limited number of these have been studied in vivo in models of Chagas' disease. Herein, we survey some of the cantidates able to surpass the "hit-to-lead" stage discussing their limitations or merit to enter in clinical trials in the short term.
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Affiliation(s)
- Hugo Cerecetto
- Departamento de Química Orgánica, Facultad de Química, Universidad de la República, Iguá 4225, Montevideo 11400, Uruguay.
| | - Mercedes González
- Laboratorio de Química Orgánica, Instituto de Química Biológica-Facultad de Ciencias, Universidad de la República, Iguá 4225, Montevideo 11400, Uruguay.
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Urbina JA. Ergosterol biosynthesis and drug development for Chagas disease. Mem Inst Oswaldo Cruz 2010; 104 Suppl 1:311-8. [PMID: 19753490 DOI: 10.1590/s0074-02762009000900041] [Citation(s) in RCA: 146] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2009] [Accepted: 05/18/2009] [Indexed: 12/13/2022] Open
Abstract
This article presents an overview of the currently available drugs nifurtimox (NFX) and benznidazole (BZN) used against Trypanosoma cruzi, the aetiological agent of Chagas disease; herein we discuss their limitations along with potential alternatives with a focus on ergosterol biosynthesis inhibitors (EBI). These compounds are currently the most advanced candidates for new anti-T. cruzi agents given that they block de novo production of 24-alkyl-sterols, which are essential for parasite survival and cannot be replaced by a host's own cholesterol. Among these compounds, new triazole derivatives that inhibit the parasite's C14alpha sterol demethylase are the most promising, as they have been shown to have curative activity in murine models of acute and chronic Chagas disease and are active against NFX and BZN-resistant T. cruzi strains; among this class of compounds, posaconazole (Schering-Plough Research Institute) and ravuconazole (Eisai Company) are poised for clinical trials in Chagas disease patients in the short term. Other T. cruzi-specific EBI, with in vitro and in vivo potency, include squalene synthase, lanosterol synthase and squalene epoxidase-inhibitors as well as compounds with dual mechanisms of action (ergosterol biosynthesis inhibition and free radical generation), but they are less advanced in their development process. The main putative advantages of EBI over currently available therapies include their higher potency and selectivity in both acute and chronic infections, activity against NFX and BZN-resistant T. cruzi strains, and much better tolerability and safety profiles. Limitations may include complexity and cost of manufacture of the new compounds. As for any new drug, such compounds will require extensive clinical testing before being introduced for clinical use, and the complexity of such studies, particularly in chronic patients, will be compounded by the current limitations in the verification of true parasitological cures for T. cruzi infections.
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Affiliation(s)
- Julio A Urbina
- Instituto Venezolano de Investigaciones Científicas, Caracas, Venezuela.
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Sterol Biosynthesis Pathway as Target for Anti-trypanosomatid Drugs. Interdiscip Perspect Infect Dis 2009; 2009:642502. [PMID: 19680554 PMCID: PMC2721973 DOI: 10.1155/2009/642502] [Citation(s) in RCA: 131] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2009] [Accepted: 04/27/2009] [Indexed: 12/03/2022] Open
Abstract
Sterols are constituents of the cellular membranes that are essential for their normal structure and function. In mammalian cells, cholesterol is the main sterol found in the various membranes. However, other sterols predominate in eukaryotic microorganisms such as fungi and protozoa. It is now well established that an important metabolic pathway in fungi and in members of the Trypanosomatidae family is one that produces a special class of sterols, including ergosterol, and other 24-methyl sterols, which are required for parasitic growth and viability, but are absent from mammalian host cells. Currently, there are several drugs that interfere with sterol biosynthesis (SB) that are in use to treat diseases such as high cholesterol in humans and fungal infections. In this review, we analyze the effects of drugs such as (a) statins, which act on the mevalonate pathway by inhibiting HMG-CoA reductase, (b) bisphosphonates, which interfere with the isoprenoid pathway in the step catalyzed by farnesyl diphosphate synthase, (c) zaragozic acids and quinuclidines, inhibitors of squalene synthase (SQS), which catalyzes the first committed step in sterol biosynthesis, (d) allylamines, inhibitors of squalene epoxidase, (e) azoles, which inhibit C14α-demethylase, and (f) azasterols, which inhibit Δ24(25)-sterol methyltransferase (SMT). Inhibition of this last step appears to have high selectivity for fungi and trypanosomatids, since this enzyme is not found in mammalian cells. We review here the IC50 values of these various inhibitors, their effects on the growth of trypanosomatids (both in axenic cultures and in cell cultures), and their effects on protozoan structural organization (as evaluted by light and electron microscopy) and lipid composition. The results show that the mitochondrial membrane as well as the membrane lining the protozoan cell body and flagellum are the main targets. Probably as a consequence of these primary effects, other important changes take place in the organization of the kinetoplast DNA network and on the protozoan cell cycle. In addition, apoptosis-like and autophagic processes induced by several of the inhibitors tested led to parasite death.
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Ribeiro I, Sevcsik AM, Alves F, Diap G, Don R, Harhay MO, Chang S, Pecoul B. New, improved treatments for Chagas disease: from the R&D pipeline to the patients. PLoS Negl Trop Dis 2009; 3:e484. [PMID: 19582163 PMCID: PMC2702098 DOI: 10.1371/journal.pntd.0000484] [Citation(s) in RCA: 118] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Affiliation(s)
- Isabela Ribeiro
- Drugs for Neglected Diseases
initiative, Geneva, Switzerland
| | | | - Fabiana Alves
- Drugs for Neglected Diseases
initiative, Geneva, Switzerland
| | - Graciela Diap
- Drugs for Neglected Diseases
initiative, Geneva, Switzerland
| | - Robert Don
- Drugs for Neglected Diseases
initiative, Geneva, Switzerland
| | - Michael O. Harhay
- Masters of Public Health Program, University
of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, United States of
America
| | - Shing Chang
- Drugs for Neglected Diseases
initiative, Geneva, Switzerland
| | - Bernard Pecoul
- Drugs for Neglected Diseases
initiative, Geneva, Switzerland
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Soeiro MNC, de Castro SL. Trypanosoma cruzitargets for new chemotherapeutic approaches. Expert Opin Ther Targets 2008; 13:105-21. [DOI: 10.1517/14728220802623881] [Citation(s) in RCA: 100] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Niemirowicz G, Fernández D, Solà M, Cazzulo JJ, Avilés FX, Gomis-Rüth FX. The molecular analysis of Trypanosoma cruzi metallocarboxypeptidase 1 provides insight into fold and substrate specificity. Mol Microbiol 2008; 70:853-66. [PMID: 18793339 DOI: 10.1111/j.1365-2958.2008.06444.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Trypanosoma cruzi is the aetiological agent of Chagas' disease, a chronic infection that affects millions in Central and South America. Proteolytic enzymes are involved in the development and progression of this disease and two metallocarboxypeptidases, isolated from T. cruzi CL Brener clone, have recently been characterized: TcMCP-1 and TcMCP-2. Although both are cytosolic and closely related in sequence, they display different temporary expression patterns and substrate preferences. TcMCP-1 removes basic C-terminal residues, whereas TcMCP-2 prefers hydrophobic/aromatic residues. Here we report the three-dimensional structure of TcMCP-1. It resembles an elongated cowry, with a long, deep, narrow active-site cleft mimicking the aperture. It has an N-terminal dimerization subdomain, involved in a homodimeric catalytically active quaternary structure arrangement, and a proteolytic subdomain partitioned by the cleft into an upper and a lower moiety. The cleft accommodates a catalytic metal ion, most likely a cobalt, which is co-ordinated by residues included in a characteristic zinc-binding sequence, HEXXH and a downstream glutamate. The structure of TcMCP-1 shows strong topological similarity with archaeal, bacterial and mammalian metallopeptidases including angiotensin-converting enzyme, neurolysin and thimet oligopeptidase. A crucial residue for shaping the S(1') pocket in TcMCP-1, Met-304, was mutated to the respective residue in TcMCP-2, an arginine, leading to a TcMCP-1 variant with TcMCP-2 specificity. The present studies pave the way for a better understanding of a potential target in Chagas' disease at the molecular level and provide a template for the design of novel therapeutic approaches.
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Affiliation(s)
- Gabriela Niemirowicz
- Instituto de Investigaciones Biotecnológicas-Instituto Tecnológico de Chascomús (IIB-INTECH), Universidad Nacional de General San Martín-CONICET, Avenida General Paz 5445, AR-1650 San Martín, Buenos Aires, Argentina
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In vitro activities of ER-119884 and E5700, two potent squalene synthase inhibitors, against Leishmania amazonensis: antiproliferative, biochemical, and ultrastructural effects. Antimicrob Agents Chemother 2008; 52:4098-114. [PMID: 18765694 DOI: 10.1128/aac.01616-07] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
ER-119884 and E5700, novel arylquinuclidine derivatives developed as cholesterol-lowering agents, were potent in vitro growth inhibitors of both proliferative stages of Leishmania amazonensis, the main causative agent of cutaneous leishmaniasis in South America, with the 50% inhibitory concentrations (IC(50)s) being in the low-nanomolar to subnanomolar range. The compounds were very potent noncompetitive inhibitors of native L. amazonensis squalene synthase (SQS), with inhibition constants also being in the nanomolar to subnanomolar range. Growth inhibition was strictly associated with the depletion of the parasite's main endogenous sterols and the concomitant accumulation of exogenous cholesterol. Using electron microscopy, we identified the intracellular structures affected by the compounds. A large number of lipid inclusions displaying different shapes and electron densities were observed after treatment with both SQS inhibitors, and these inclusions were associated with an intense disorganization of the membrane that surrounds the cell body and flagellum, as well as the endoplasmic reticulum and the Golgi complex. Cells treated with ER-119884 but not those treated with E5700 had an altered cytoskeleton organization due to an abnormal distribution of tubulin, and many were arrested at cytokinesis. A prominent contractile vacuole and a phenotype typical of programmed cell death were frequently found in drug-treated cells. The selectivity of the drugs was demonstrated with the JC-1 mitochondrial fluorescent label and by trypan blue exclusion tests with macrophages, which showed that the IC(50)s against the host cells were 4 to 5 orders of magnitude greater that those against the intracellular parasites. Taken together, our results show that ER-119884 and E5700 are unusually potent and selective inhibitors of the growth of Leishmania amazonensis, probably because of their inhibitory effects on de novo sterol biosynthesis at the level of SQS, but some of our observations indicate that ER-119884 may also interfere with other cellular processes.
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Cloning, solubilization, and characterization of squalene synthase from Thermosynechococcus elongatus BP-1. J Bacteriol 2008; 190:3808-16. [PMID: 18375558 DOI: 10.1128/jb.01939-07] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Squalene synthase (SQS) is a bifunctional enzyme that catalyzes the condensation of two molecules of farnesyl diphosphate (FPP) to give presqualene diphosphate (PSPP) and the subsequent rearrangement of PSPP to squalene. These reactions constitute the first pathway-specific steps in hopane biosynthesis in Bacteria and sterol biosynthesis in Eukarya. The genes encoding SQS were isolated from the hopane-producing bacteria Thermosynechococcus elongatus BP-1, Bradyrhizobium japonicum, and Zymomonas mobilis and cloned into an Escherichia coli expression system. The expressed proteins with a His(6) tag were found exclusively in inclusion bodies when no additives were used in the buffer. After extensive optimization, soluble recombinant T. elongatus BP-1 SQS was obtained when cells were disrupted and purified in buffers containing glycerol. The recombinant B. japonicum and Z. mobilis SQSs could not be solubilized under any of the expression and purification conditions used. Purified T. elongatus His(6)-SQS gave a single band at 42 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and molecular ion at m/z 41886 by electrospray mass spectrometry. Incubation with FPP and NADPH gave squalene as the sole product. Incubation of the enzyme with [(14)C]FPP in the absence of NADPH gave PSPP. The enzyme requires Mg(2+) for activity, has an optimum pH of 7.6, and is strongly stimulated by detergent. Under optimal conditions, the K(m) of FPP is 0.97 +/- 0.10 microM and the k(cat) is 1.74 +/- 0.04 s(-1). Zaragozic acid A, a potent inhibitor of mammalian, fungal, and Saccharomyces cerevisiae SQSs, also inhibited recombinant T. elongatus BP-1 SQS, with a 50% inhibitory concentration of 95.5 +/- 13.6 nM.
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