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Hdoufane I, Bjij I, Oubahmane M, Soliman MES, Villemin D, Cherqaoui D. In silico design and analysis of NS4B inhibitors against hepatitis C virus. J Biomol Struct Dyn 2020; 40:1915-1929. [PMID: 33118481 DOI: 10.1080/07391102.2020.1839561] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The hepatitis C virus is a communicable disease that gradually harms the liver leading to cirrhosis and hepatocellular carcinoma. Important therapeutic interventions have been reached since the discovery of the disease. However, its resurgence urges the need for new approaches against this malady. The NS4B receptor is one of the important proteins for Hepatitis C Virus RNA replication that acts by mediating different viral properties. In this work, we opt to explore the relationships between the molecular structures of biologically tested NS4B inhibitors and their corresponding inhibitory activities to assist the design of novel and potent NS4B inhibitors. For that, a set of 115 indol-2-ylpyridine-3-sulfonamides (IPSA) compounds with inhibitory activity against NS4B is used. A hybrid genetic algorithm combined with multiple linear regressions (GA-MLR) was implemented to construct a predictive model. This model was further used and applied to a set of compounds that were generated based on a pharmacophore modeling study combined with virtual screening to identify structurally similar lead compounds. Multiple filtrations were implemented for selecting potent hits. The selected hits exhibited advantageous molecular features, allowing for favorable inhibitory activity against HCV. The results showed that 7 out of 1285 screened compounds, were selected as potent candidate hits where Zinc14822482 exhibits the best predicted potency and pharmacophore features. The predictive pharmacokinetic analysis further justified the compounds as potential hit molecules, prompting their recommendation for a confirmatory biological evaluation. We believe that our strategy could help in the design and screening of potential inhibitors in drug discovery.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Ismail Hdoufane
- Department of Chemistry, Faculty of Science Semlalia, Laboratory of Molecular Chemistry, Marrakech, Morocco
| | - Imane Bjij
- Department of Chemistry, Faculty of Science Semlalia, Laboratory of Molecular Chemistry, Marrakech, Morocco.,School of Health Sciences, University of KwaZulu-Natal, Westville, Durban, South Africa
| | - Mehdi Oubahmane
- Department of Chemistry, Faculty of Science Semlalia, Laboratory of Molecular Chemistry, Marrakech, Morocco
| | - Mahmoud E S Soliman
- School of Health Sciences, University of KwaZulu-Natal, Westville, Durban, South Africa
| | - Didier Villemin
- Ecole Nationale Supérieure d'Ingénieurs (E.N.S.I.) I. S. M. R. A., LCMT, UMR CNRS n° 6507, Caen, France
| | - Driss Cherqaoui
- Department of Chemistry, Faculty of Science Semlalia, Laboratory of Molecular Chemistry, Marrakech, Morocco
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2
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Inhibitory mechanism of 5-bromo-3-indoleacetic acid for non-structural-3 helicase hepatitis C virus with dynamics correlation network analysis. Comput Biol Chem 2018; 77:167-177. [DOI: 10.1016/j.compbiolchem.2018.10.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Revised: 09/03/2018] [Accepted: 10/06/2018] [Indexed: 01/20/2023]
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3
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Chen S, Yang C, Zhang W, Mahalingam S, Wang M, Cheng A. Flaviviridae virus nonstructural proteins 5 and 5A mediate viral immune evasion and are promising targets in drug development. Pharmacol Ther 2018; 190:1-14. [PMID: 29742479 DOI: 10.1016/j.pharmthera.2018.05.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Infections with viruses in the Flaviviridae family have a vast global and economic impact because of the high morbidity and mortality. The pathogenesis of Flaviviridae infections is very complex and not fully understood because these viruses can inhibit multiple immune pathways including the complement system, NK cells, and IFN induction and signalling pathways. The non-structural (NS) 5 and 5A proteins of Flaviviridae viruses are highly conserved and play an important role in resisting host immunity through various evasion mechanisms. This review summarizes the strategies used by the NS5 and 5A proteins of Flaviviridae viruses for evading the innate immune response by inhibiting pattern recognition receptor (PRR) signalling pathways (TLR/MyD88, IRF7), suppressing interferon (IFN) signalling pathways (IFN-γRs, STAT1, STAT2), and impairing the function of IFN-stimulated genes (ISGs) (e.g. protein kinase R [PKR], oligoadenylate synthase [OAS]). All of these immune evasion mechanisms depend on the interaction of NS5 or NS5A with cellular proteins, such as MyD88 and IRF7, IFN-αRs, IFN-γRs, STAT1, STAT2, PKR and OAS. NS5 is the most attractive target for the discovery of broad spectrum compounds against Flaviviridae virus infection. The methyltransferase (MTase) and RNA-dependent RNA polymerase (RdRp) activities of NS5 are the main therapeutic targets for antiviral drugs against Flaviviridae virus infection. Based on our site mapping, the sites involved in immune evasion provide some potential and promising targets for further novel antiviral therapeutics.
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Affiliation(s)
- Shun Chen
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan 611130, China; Research Center of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, Sichuan 611130, China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan 611130, China.
| | - Chao Yang
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan 611130, China
| | - Wei Zhang
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan 611130, China
| | - Suresh Mahalingam
- Emerging Viruses and Inflammation Research Group, Institute for Glycomics, Griffith University, Gold Coast, Australia
| | - Mingshu Wang
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan 611130, China; Research Center of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, Sichuan 611130, China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan 611130, China
| | - Anchun Cheng
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan 611130, China; Research Center of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, Sichuan 611130, China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan 611130, China.
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Forni D, Cagliani R, Pontremoli C, Pozzoli U, Vertemara J, De Gioia L, Clerici M, Sironi M. Evolutionary Analysis Provides Insight Into the Origin and Adaptation of HCV. Front Microbiol 2018; 9:854. [PMID: 29765366 PMCID: PMC5938362 DOI: 10.3389/fmicb.2018.00854] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Accepted: 04/13/2018] [Indexed: 12/12/2022] Open
Abstract
Hepatitis C virus (HCV) belongs to the Hepacivirus genus and is genetically heterogeneous, with seven major genotypes further divided into several recognized subtypes. HCV origin was previously dated in a range between ∼200 and 1000 years ago. Hepaciviruses have been identified in several domestic and wild mammals, the largest viral diversity being observed in bats and rodents. The closest relatives of HCV were found in horses/donkeys (equine hepaciviruses, EHV). However, the origin of HCV as a human pathogen is still an unsolved puzzle. Using a selection-informed evolutionary model, we show that the common ancestor of extant HCV genotypes existed at least 3000 years ago (CI: 3192–5221 years ago), with the oldest genotypes being endemic to Asia. EHV originated around 1100 CE (CI: 291–1640 CE). These time estimates exclude that EHV transmission was mainly sustained by widespread veterinary practices and suggest that HCV originated from a single zoonotic event with subsequent diversification in human populations. We also describe a number of biologically important sites in the major HCV genotypes that have been positively selected and indicate that drug resistance-associated variants are significantly enriched at positively selected sites. HCV exploits several cell-surface molecules for cell entry, but only two of these (CD81 and OCLN) determine the species-specificity of infection. Herein evolutionary analyses do not support a long-standing association between primates and hepaciviruses, and signals of positive selection at CD81 were only observed in Chiroptera. No evidence of selection was detected for OCLN in any mammalian order. These results shed light on the origin of HCV and provide a catalog of candidate genetic modulators of HCV phenotypic diversity.
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Affiliation(s)
- Diego Forni
- Bioinformatics Laboratory, Scientific Institute IRCCS E.Medea, Bosisio Parini, Italy
| | - Rachele Cagliani
- Bioinformatics Laboratory, Scientific Institute IRCCS E.Medea, Bosisio Parini, Italy
| | - Chiara Pontremoli
- Bioinformatics Laboratory, Scientific Institute IRCCS E.Medea, Bosisio Parini, Italy
| | - Uberto Pozzoli
- Bioinformatics Laboratory, Scientific Institute IRCCS E.Medea, Bosisio Parini, Italy
| | - Jacopo Vertemara
- Department of Biotechnology and Biosciences, University of Milan-Bicocca, Milan, Italy
| | - Luca De Gioia
- Department of Biotechnology and Biosciences, University of Milan-Bicocca, Milan, Italy
| | - Mario Clerici
- Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy.,Don C. Gnocchi Foundation Onlus, IRCCS, Milan, Italy
| | - Manuela Sironi
- Bioinformatics Laboratory, Scientific Institute IRCCS E.Medea, Bosisio Parini, Italy
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5
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Jin G, Lee J, Lee K. Chemical genetics-based development of small molecules targeting hepatitis C virus. Arch Pharm Res 2017; 40:1021-1036. [PMID: 28856597 DOI: 10.1007/s12272-017-0949-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Accepted: 08/20/2017] [Indexed: 12/21/2022]
Abstract
Hepatitis C virus (HCV) infection is a major worldwide problem that has emerged as one of the most significant diseases affecting humans. There are currently no vaccines or efficient therapies without side effects, despite today's advanced medical technology. Currently, the common therapy for most patients (i.e. genotype 1) is combination of HCV-specific direct-acting antivirals (DAAs). Up to 2011, the standard of care (SOC) was a combination of peg-IFNα with ribavirin (RBV). After approval of NS3/4A protease inhibitor, SOC was peg-IFNα and RBV with either the first-generation DAAs boceprevir or telaprevir. In the past several years, various novel small molecules have been discovered and some of them (i.e., HCV polymerase, protease, helicase and entry inhibitors) have undergone clinical trials. Between 2013 and 2016, the second-generation DAA drugs simeprevir, asunaprevir, daclatasvir, dasabuvir, sofosbuvir, and elbasvir were approved, as well as the combinational drugs Harvoni®, Zepatier®, Technivie®, and Epclusa®. A number of reviews have been recently published describing the structure-activity relationship (SAR) in the development of HCV inhibitors and outlining current therapeutic approaches to hepatitis C infection. Target identification involves studying a drug's mechanism of action (MOA), and a variety of target identification methods have been developed in the past few years. Chemical biology has emerged as a powerful tool for studying biological processes using small molecules. The use of chemical genetic methods is a valuable strategy for studying the molecular mechanisms of the viral lifecycle and screening for anti-viral agents. Two general screening approaches have been employed: forward and reverse chemical genetics. This review reveals information on the small molecules in HCV drug discovery by using chemical genetics for targeting the HCV protein and describes successful examples of targets identified with these methods.
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Affiliation(s)
- Guanghai Jin
- College of Pharmacy, Dongguk University-Seoul, Goyang, 10326, Republic of Korea
| | - Jisu Lee
- College of Pharmacy, Dongguk University-Seoul, Goyang, 10326, Republic of Korea
| | - Kyeong Lee
- College of Pharmacy, Dongguk University-Seoul, Goyang, 10326, Republic of Korea.
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6
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Shape-based virtual screening, synthesis and evaluation of novel pyrrolone derivatives as antiviral agents against HCV. Bioorg Med Chem Lett 2017; 27:936-940. [DOI: 10.1016/j.bmcl.2016.12.087] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Revised: 12/30/2016] [Accepted: 12/31/2016] [Indexed: 12/18/2022]
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7
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Bassetto M, Ferla S, Leyssen P, Neyts J, Yerukhimovich MM, Frick DN, O'Donnell R, Brancale A. Novel symmetrical phenylenediamines as potential anti-hepatitis C virus agents. Antivir Chem Chemother 2016; 24:155-160. [PMID: 27815332 DOI: 10.1177/2040206616676353] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Despite the great progress made in the last 10 years, alternative strategies might help improving definitive treatment options against hepatitis C virus infection. METHODS With the aim of identifying novel inhibitors of the hepatitis C virus-1b replication targeting the viral NS3 helicase, the structures of previously reported symmetrical inhibitors of this enzyme were rationally modified, and according to docking-based studies, four novel scaffolds were selected for synthesis and evaluation in the hepatitis C virus-1b subgenomic replicon assay. RESULTS Among the newly designed compounds, one new structural family was found to inhibit the hepatitis C virus-1b replication in the micromolar range. This scaffold was chosen for further exploration and different novel analogues were synthesised and evaluated. CONCLUSIONS Different new inhibitors of the hepatitis C virus genotype 1b replication were identified. Some of the new compounds show mild inhibition of the NS3 helicase enzyme.
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Affiliation(s)
- Marcella Bassetto
- 1 Cardiff School of Pharmacy and Pharmaceutical Sciences, Cardiff, UK
| | - Salvatore Ferla
- 1 Cardiff School of Pharmacy and Pharmaceutical Sciences, Cardiff, UK
| | - Pieter Leyssen
- 2 Rega Institute for Medical Research, University of Leuven, Leuven, Belgium
| | - Johan Neyts
- 2 Rega Institute for Medical Research, University of Leuven, Leuven, Belgium
| | - Mark M Yerukhimovich
- 3 Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, USA
| | - David N Frick
- 3 Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, USA
| | - Rachel O'Donnell
- 1 Cardiff School of Pharmacy and Pharmaceutical Sciences, Cardiff, UK
| | - Andrea Brancale
- 1 Cardiff School of Pharmacy and Pharmaceutical Sciences, Cardiff, UK
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Bassetto M, Leyssen P, Neyts J, Yerukhimovich MM, Frick DN, Courtney-Smith M, Brancale A. In silico identification, design and synthesis of novel piperazine-based antiviral agents targeting the hepatitis C virus helicase. Eur J Med Chem 2016; 125:1115-1131. [PMID: 27810598 DOI: 10.1016/j.ejmech.2016.10.043] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Revised: 10/17/2016] [Accepted: 10/18/2016] [Indexed: 01/26/2023]
Abstract
A structure-based virtual screening of commercial compounds was carried out on the HCV NS3 helicase structure, with the aim to identify novel inhibitors of HCV replication. Among a selection of 13 commercial structures, one compound was found to inhibit the subgenomic HCV replicon in the low micromolar range. Different series of new piperazine-based analogues were designed and synthesised, and among them, several novel structures exhibited antiviral activity in the HCV replicon assay. Some of the new compounds were also found to inhibit HCV NS3 helicase function in vitro, and one directly bound NS3 with a dissociation constant of 570 ± 270 nM.
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Affiliation(s)
- Marcella Bassetto
- Cardiff School of Pharmacy and Pharmaceutical Sciences, Cardiff, King Edward VII Avenue, Cardiff CF103NB, UK.
| | - Pieter Leyssen
- Rega Institute for Medical Research, University of Leuven, Belgium
| | - Johan Neyts
- Rega Institute for Medical Research, University of Leuven, Belgium
| | - Mark M Yerukhimovich
- Department of Chemistry & Biochemistry, University of Wisconsin- Milwaukee, Milwaukee, WI 53211, United States
| | - David N Frick
- Department of Chemistry & Biochemistry, University of Wisconsin- Milwaukee, Milwaukee, WI 53211, United States
| | - Matthew Courtney-Smith
- Cardiff School of Pharmacy and Pharmaceutical Sciences, Cardiff, King Edward VII Avenue, Cardiff CF103NB, UK
| | - Andrea Brancale
- Cardiff School of Pharmacy and Pharmaceutical Sciences, Cardiff, King Edward VII Avenue, Cardiff CF103NB, UK
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9
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Computer-aided identification, synthesis and evaluation of substituted thienopyrimidines as novel inhibitors of HCV replication. Eur J Med Chem 2016; 123:31-47. [PMID: 27474921 DOI: 10.1016/j.ejmech.2016.07.035] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Revised: 06/24/2016] [Accepted: 07/18/2016] [Indexed: 01/30/2023]
Abstract
A structure-based virtual screening technique was applied to the study of the HCV NS3 helicase, with the aim to find novel inhibitors of the HCV replication. A library of ∼450000 commercially available compounds was analysed in silico and 21 structures were selected for biological evaluation in the HCV replicon assay. One hit characterized by a substituted thieno-pyrimidine scaffold was found to inhibit the viral replication with an EC50 value in the sub-micromolar range and a good selectivity index. Different series of novel thieno-pyrimidine derivatives were designed and synthesised; several new structures showed antiviral activity in the low or sub-micromolar range.
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Fogeron ML, Jirasko V, Penzel S, Paul D, Montserret R, Danis C, Lacabanne D, Badillo A, Gouttenoire J, Moradpour D, Bartenschlager R, Penin F, Meier BH, Böckmann A. Cell-free expression, purification, and membrane reconstitution for NMR studies of the nonstructural protein 4B from hepatitis C virus. JOURNAL OF BIOMOLECULAR NMR 2016; 65:87-98. [PMID: 27233794 DOI: 10.1007/s10858-016-0040-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Accepted: 05/21/2016] [Indexed: 06/05/2023]
Abstract
We describe the expression of the hepatitis C virus nonstructural protein 4B (NS4B), which is an integral membrane protein, in a wheat germ cell-free system, the subsequent purification and characterization of NS4B and its insertion into proteoliposomes in amounts sufficient for multidimensional solid-state NMR spectroscopy. First spectra of the isotopically [(2)H,(13)C,(15)N]-labeled protein are shown to yield narrow (13)C resonance lines and a proper, predominantly α-helical fold. Clean residue-selective leucine, isoleucine and threonine-labeling is demonstrated. These results evidence the suitability of the wheat germ-produced integral membrane protein NS4B for solid-state NMR. Still, the proton linewidth under fast magic angle spinning is broader than expected for a perfect sample and possible causes are discussed.
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Affiliation(s)
- Marie-Laure Fogeron
- Institut de Biologie et Chimie des Protéines, Bases Moléculaires et Structurales des Systèmes Infectieux, Labex Ecofect, UMR 5086 CNRS, Université de Lyon, 7 passage du Vercors, 69367, Lyon, France
| | - Vlastimil Jirasko
- Physical Chemistry, ETH Zurich, 8093, Zurich, Switzerland
- Department of Infectious Diseases, Molecular Virology, Heidelberg University, Im Neuenheimer Feld 345, 69120, Heidelberg, Germany
- German Centre for Infection Research (DZIF), Partner Site Heidelberg, Heidelberg, Germany
| | - Susanne Penzel
- Physical Chemistry, ETH Zurich, 8093, Zurich, Switzerland
| | - David Paul
- Department of Infectious Diseases, Molecular Virology, Heidelberg University, Im Neuenheimer Feld 345, 69120, Heidelberg, Germany
- German Centre for Infection Research (DZIF), Partner Site Heidelberg, Heidelberg, Germany
| | - Roland Montserret
- Institut de Biologie et Chimie des Protéines, Bases Moléculaires et Structurales des Systèmes Infectieux, Labex Ecofect, UMR 5086 CNRS, Université de Lyon, 7 passage du Vercors, 69367, Lyon, France
| | - Clément Danis
- Institut de Biologie et Chimie des Protéines, Bases Moléculaires et Structurales des Systèmes Infectieux, Labex Ecofect, UMR 5086 CNRS, Université de Lyon, 7 passage du Vercors, 69367, Lyon, France
| | - Denis Lacabanne
- Institut de Biologie et Chimie des Protéines, Bases Moléculaires et Structurales des Systèmes Infectieux, Labex Ecofect, UMR 5086 CNRS, Université de Lyon, 7 passage du Vercors, 69367, Lyon, France
| | - Aurélie Badillo
- Institut de Biologie et Chimie des Protéines, Bases Moléculaires et Structurales des Systèmes Infectieux, Labex Ecofect, UMR 5086 CNRS, Université de Lyon, 7 passage du Vercors, 69367, Lyon, France
- Recombinant Protein Unit, RD-Biotech, 3 rue Henri Baigue, 25000, Besançon, France
| | - Jérôme Gouttenoire
- Division of Gastroenterology and Hepatology, Centre Hospitalier Universitaire Vaudois, University of Lausanne, 1011, Lausanne, Switzerland
| | - Darius Moradpour
- Division of Gastroenterology and Hepatology, Centre Hospitalier Universitaire Vaudois, University of Lausanne, 1011, Lausanne, Switzerland
| | - Ralf Bartenschlager
- Department of Infectious Diseases, Molecular Virology, Heidelberg University, Im Neuenheimer Feld 345, 69120, Heidelberg, Germany
- German Centre for Infection Research (DZIF), Partner Site Heidelberg, Heidelberg, Germany
| | - François Penin
- Institut de Biologie et Chimie des Protéines, Bases Moléculaires et Structurales des Systèmes Infectieux, Labex Ecofect, UMR 5086 CNRS, Université de Lyon, 7 passage du Vercors, 69367, Lyon, France
| | - Beat H Meier
- Physical Chemistry, ETH Zurich, 8093, Zurich, Switzerland.
| | - Anja Böckmann
- Institut de Biologie et Chimie des Protéines, Bases Moléculaires et Structurales des Systèmes Infectieux, Labex Ecofect, UMR 5086 CNRS, Université de Lyon, 7 passage du Vercors, 69367, Lyon, France.
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11
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Glab-Ampai K, Malik AA, Chulanetra M, Thanongsaksrikul J, Thueng-In K, Srimanote P, Tongtawe P, Chaicumpa W. Inhibition of HCV replication by humanized-single domain transbodies to NS4B. Biochem Biophys Res Commun 2016; 476:654-664. [PMID: 27240954 DOI: 10.1016/j.bbrc.2016.05.109] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2016] [Accepted: 05/21/2016] [Indexed: 12/21/2022]
Abstract
NS4B of hepatitis C virus (HCV) initiates membrane web formation, binds RNA and other HCV proteins for viral replication complex (RC) formation, hydrolyses NTP, and inhibits innate anti-viral immunity. Thus, NS4B is an attractive target of a novel anti-HCV agent. In this study, humanized-nanobodies (VHs/VHHs) that bound to recombinant NS4B were produced by means of phage display technology. The nanobodies were linked molecularly to a cell penetrating peptide, penetratin (PEN), for making them cell penetrable (become transbodies). Human hepatic (Huh7) cells transfected with HCV JFH1-RNA that were treated with transbodies from four Escherichia coli clones (PEN-VHH7, PEN-VHH9, PEN-VH33, and PEN-VH43) had significant reduction of HCV RNA amounts in their culture fluids and intracellularly when compared to the transfected cells treated with control transbody and medium alone. The results were supported by the HCV foci assay. The transbody treated-transfected cells also had upregulation of the studied innate cytokine genes, IRF3, IFNβ and IL-28b. The transbodies have high potential for testing further as a novel anti-HCV agent, either alone, adjunct of existing anti-HCV agents/remedies, or in combination with their cognates specific to other HCV enzymes/proteins.
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MESH Headings
- Antibodies, Monoclonal, Humanized/administration & dosage
- Antibodies, Monoclonal, Humanized/chemistry
- Antibodies, Monoclonal, Humanized/genetics
- Antibodies, Viral/administration & dosage
- Antibodies, Viral/chemistry
- Antibodies, Viral/genetics
- Antiviral Agents/administration & dosage
- Antiviral Agents/chemistry
- Carrier Proteins/administration & dosage
- Carrier Proteins/chemistry
- Carrier Proteins/genetics
- Cell Line
- Cell Surface Display Techniques
- Cell-Penetrating Peptides/administration & dosage
- Cell-Penetrating Peptides/chemistry
- Cell-Penetrating Peptides/genetics
- Computer Simulation
- Hepacivirus/genetics
- Hepacivirus/immunology
- Hepacivirus/physiology
- Humans
- Immunity, Innate/genetics
- Models, Molecular
- Recombinant Proteins/chemistry
- Recombinant Proteins/genetics
- Recombinant Proteins/immunology
- Single-Domain Antibodies/administration & dosage
- Single-Domain Antibodies/chemistry
- Single-Domain Antibodies/genetics
- Transfection
- Viral Nonstructural Proteins/genetics
- Viral Nonstructural Proteins/immunology
- Viral Nonstructural Proteins/physiology
- Virus Replication/genetics
- Virus Replication/immunology
- Virus Replication/physiology
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Affiliation(s)
- Kittirat Glab-Ampai
- Graduate Program in Immunology, Department of Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand; Center of Research Excellence on Therapeutic Proteins and Antibody Engineering, Department of Parasitology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Aijaz Ahmad Malik
- Graduate Program in Immunology, Department of Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand; Center of Research Excellence on Therapeutic Proteins and Antibody Engineering, Department of Parasitology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Monrat Chulanetra
- Center of Research Excellence on Therapeutic Proteins and Antibody Engineering, Department of Parasitology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Jeeraphong Thanongsaksrikul
- Graduate Program in Biomedical Science, Faculty of Allied Health Sciences, Thammasat University, Pathumthani 12120, Thailand
| | - Kanyarat Thueng-In
- Center of Research Excellence on Therapeutic Proteins and Antibody Engineering, Department of Parasitology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand; School of Pathology, Institute of Medicine, Suranaree University of Technology, Nakhonratchaseema Province 30000, Thailand
| | - Potjanee Srimanote
- Graduate Program in Biomedical Science, Faculty of Allied Health Sciences, Thammasat University, Pathumthani 12120, Thailand
| | - Pongsri Tongtawe
- Graduate Program in Biomedical Science, Faculty of Allied Health Sciences, Thammasat University, Pathumthani 12120, Thailand
| | - Wanpen Chaicumpa
- Center of Research Excellence on Therapeutic Proteins and Antibody Engineering, Department of Parasitology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand; Graduate Program in Biomedical Science, Faculty of Allied Health Sciences, Thammasat University, Pathumthani 12120, Thailand.
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12
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Manvar P, Shaikh F, Kakadiya R, Mehariya K, Khunt R, Pandey B, Shah A. Synthesis of novel imidazo[1,2-a]pyridine-4-hydroxy-2H-coumarins by Groebke–Blackburn–Bienaymé multicomponent reaction as potential NS5B inhibitors. Tetrahedron 2016. [DOI: 10.1016/j.tet.2016.01.023] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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13
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Savardashtaki A, Sharifi Z, Hamzehlou S, Farajollahi MM. Analysis of Immumoreactivity of Heterologously Expressed Non-structural Protein 4B (NS4B) from Hepatitis C Virus (HCV) Genotype 1a. IRANIAN JOURNAL OF BIOTECHNOLOGY 2015; 13:32-37. [PMID: 28959307 DOI: 10.15171/ijb.1321] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
BACKGROUND Detection of hepatitis C virus specific antibodies is the initial step in chronic HCV diagnosis. HCV NS4B is among the most immunogenic HCV antigens and has been widely used in commercial Enzyme Immunoassays (EIA). Additionally, NS4B, a key protein in the virus replication, can be an alternative target for antiviral therapy. OBJECTIVES Development of a new method for high-level expression and purification of NS4B coding region was the aim of the report. MATERIALS AND METHODS Viral RNA was purified from the serum of an HCV positive patient and NS4B coding region was amplified using nested RT-PCR. PCR products were cloned into pET102/D-TOPO expression vector and transformed into E. coli BL21. Induction was performed by adding 1 mM isopropyl-β-D-thiogalactopyranoside (IPTG) to the culture medium. Immunoreactivity of the purified recombinant proteins was evaluated by immunoblotting and indirect enzymelinked immunosorbent assay (ELISA). RESULTS The recombinant NS4B protein was expressed and its immunoreactivity was confirmed by ELISA and western blotting. CONCLUSIONS The directional TOPO cloning provides an efficient and easy platform for heterologous expression of immunoreactive HCV NS4B.
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Affiliation(s)
- Amir Savardashtaki
- Cellular and Molecular Research Center, Department of Medical Biotechnology, Faculty of Allied Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Zohreh Sharifi
- Department of Virology, Iranian Blood Transfusion Organization, Tehran, Iran
| | - Sepideh Hamzehlou
- Cellular and Molecular Research Center, Department of Medical Biotechnology, Faculty of Allied Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Mohammad M Farajollahi
- Cellular and Molecular Research Center, Department of Medical Biotechnology, Faculty of Allied Medicine, Iran University of Medical Sciences, Tehran, Iran
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14
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Zhang N, Turpoff A, Zhang X, Huang S, Liu Y, Almstead N, Njoroge FG, Gu Z, Graci J, Jung SP, Pichardo J, Colacino J, Lahser F, Ingravallo P, Weetall M, Nomeir A, Karp GM. Discovery of 2-(4-sulfonamidophenyl)-indole 3-carboxamides as potent and selective inhibitors with broad hepatitis C virus genotype activity targeting HCV NS4B. Bioorg Med Chem Lett 2015; 26:594-601. [PMID: 26652483 DOI: 10.1016/j.bmcl.2015.11.065] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2015] [Revised: 11/13/2015] [Accepted: 11/19/2015] [Indexed: 01/24/2023]
Abstract
A novel series of 2-(4-sulfonamidophenyl)-indole 3-carboxamides was identified and optimized for activity against the HCV genotype 1b replicon resulting in compounds with potent and selective activity. Further evaluation of this series demonstrated potent activity across HCV genotypes 1a, 2a and 3a. Compound 4z had reduced activity against HCV genotype 1b replicons containing single mutations in the NS4B coding sequence (F98C and V105M) indicating that NS4B is the target. This novel series of 2-(4-sulfonamidophenyl)-indole 3-carboxamides serves as a promising starting point for a pan-genotype HCV discovery program.
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Affiliation(s)
- Nanjing Zhang
- PTC Therapeutics, Inc., 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - Anthony Turpoff
- PTC Therapeutics, Inc., 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - Xiaoyan Zhang
- PTC Therapeutics, Inc., 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - Song Huang
- PTC Therapeutics, Inc., 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - Yalei Liu
- PTC Therapeutics, Inc., 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - Neil Almstead
- PTC Therapeutics, Inc., 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - F George Njoroge
- Merck Research Laboratories, 2015 Galloping Hill Road, Kenilworth, NJ 07033, USA
| | - Zhengxian Gu
- PTC Therapeutics, Inc., 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - Jason Graci
- PTC Therapeutics, Inc., 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - Stephen P Jung
- PTC Therapeutics, Inc., 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - John Pichardo
- PTC Therapeutics, Inc., 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - Joseph Colacino
- PTC Therapeutics, Inc., 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - Fred Lahser
- Merck Research Laboratories, 2015 Galloping Hill Road, Kenilworth, NJ 07033, USA
| | - Paul Ingravallo
- Merck Research Laboratories, 2015 Galloping Hill Road, Kenilworth, NJ 07033, USA
| | - Marla Weetall
- PTC Therapeutics, Inc., 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - Amin Nomeir
- Merck Research Laboratories, 2015 Galloping Hill Road, Kenilworth, NJ 07033, USA
| | - Gary M Karp
- PTC Therapeutics, Inc., 100 Corporate Court, South Plainfield, NJ 07080, USA
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15
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Cannalire R, Barreca ML, Manfroni G, Cecchetti V. A Journey around the Medicinal Chemistry of Hepatitis C Virus Inhibitors Targeting NS4B: From Target to Preclinical Drug Candidates. J Med Chem 2015; 59:16-41. [PMID: 26241789 DOI: 10.1021/acs.jmedchem.5b00825] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Hepatitis C virus (HCV) infection is a global health burden with an estimated 130-170 million chronically infected individuals and is the cause of serious liver diseases such as cirrhosis and hepatocellular carcinoma. HCV NS4B protein represents a validated target for the identification of new drugs to be added to the combination regimen recently approved. During the last years, NS4B has thus been the object of impressive medicinal chemistry efforts, which led to the identification of promising preclinical candidates. In this context, the present review aims to discuss research published on NS4B functional inhibitors focusing the attention on hit identification, hit-to-lead optimization, ADME profile evaluation, and the structure-activity relationship data raised for each compound family taken into account. The information delivered in this review will be a useful and valuable tool for those medicinal chemists dealing with research programs focused on NS4B and aimed at the identification of innovative anti-HCV compounds.
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Affiliation(s)
- Rolando Cannalire
- Department of Pharmaceutical Sciences, Università degli Studi di Perugia , Via A. Fabretti, 48-06123 Perugia, Italy
| | - Maria Letizia Barreca
- Department of Pharmaceutical Sciences, Università degli Studi di Perugia , Via A. Fabretti, 48-06123 Perugia, Italy
| | - Giuseppe Manfroni
- Department of Pharmaceutical Sciences, Università degli Studi di Perugia , Via A. Fabretti, 48-06123 Perugia, Italy
| | - Violetta Cecchetti
- Department of Pharmaceutical Sciences, Università degli Studi di Perugia , Via A. Fabretti, 48-06123 Perugia, Italy
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16
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"Too little, too late?" Will inhibitors of the hepatitis C virus p7 ion channel ever be used in the clinic? Future Med Chem 2015; 6:1893-907. [PMID: 25495983 DOI: 10.4155/fmc.14.121] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Hepatitis C virus (HCV) p7 is a virus-coded ion channel, or 'viroporin'. p7 is an essential HCV protein, promoting infectious virion production, and this process can be blocked by prototypic p7 inhibitors. However, prototype potency is weak and effects in clinical trials are unsatisfactory. Nevertheless, recent structural studies render p7 amenable to modern drug discovery, with studies supporting that effective drug-like molecules should be achievable. However, burgeoning HCV therapies clear infection in the majority of treated patients. This perspective summarizes current understanding of p7 channel function and structure, pertaining to the development of improved p7 inhibitors. We ask, 'is this too little, too late', or could p7 inhibitors play a role in the long-term management of HCV disease?
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17
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Xie X, Zou J, Wang QY, Shi PY. Targeting dengue virus NS4B protein for drug discovery. Antiviral Res 2015; 118:39-45. [DOI: 10.1016/j.antiviral.2015.03.007] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Revised: 03/06/2015] [Accepted: 03/13/2015] [Indexed: 10/23/2022]
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18
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Jiang XH, Xie YT, Jiang B, Tang MY, Ma T, Peng H. Inhibition of expression of hepatitis C virus 1b genotype core and NS4B genes in HepG2 cells using artificial microRNAs. Mol Med Rep 2015; 12:1905-13. [PMID: 25847260 DOI: 10.3892/mmr.2015.3571] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Accepted: 02/05/2015] [Indexed: 11/06/2022] Open
Abstract
The present study aimed to evaluate the silencing effect of artificial microRNAs (amiRNAs) against the hepatitis C virus (HCV) 1b (HCV1b) genotype core (C) and non-structural protein 4B (NS4B) genes. pDsRed-monomer-Core and pDsRed-monomer-NS4B plasmids, containing the target genes were constructed. A total of eight artificial micro RNA (amiRNA)-expressing plasmids, namely, pmiRE-C-mi1 to -mi4 and pmiRE-NS4B-mi1 to -mi4, were designed and constructed to interfere with various sites of the core and NS4B genes, and the amiRNA interfering plasmid and the corresponding target gene-expressing plasmid were co-transfected into HepG2 cells. At 48 h after transfection, HCV core and NS4B gene expression levels were detected using fluorescence microscopy, flow cytometry, reverse transcription quantitative polymerase chain reaction and western blot analysis. Fluorescence microscopy revealed that the target gene-transfected cells expressed red fluorescent protein, whereas the interfering plasmid-transfected cells exhibited expression of green fluorescent protein. The percentage of red fluorescent proteins and mean fluorescence intensity, as well as protein expression levels of the core and NS4B genes within the cells, which were co-transfected by the amiRNA interfering plasmid and the target gene, were significantly decreased. The results of the present study confirmed that amiRNAs may effectively and specifically inhibit the expression of HCV1b core and NS4B genes in HepG2 cells, potentially providing a novel therapeutic strategy for the treatment of HCV.
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Affiliation(s)
- Xiao-Hua Jiang
- Department of Infectious Diseases, Xiangya Hospital of Central South University, Changsha, Hunan 410087, P.R. China
| | - Yu-Tao Xie
- Department of Infectious Diseases, Xiangya Hospital of Central South University, Changsha, Hunan 410087, P.R. China
| | - Bo Jiang
- Department of Infectious Diseases, The First Affiliated Hospital of The University of South China, Hengyang, Hunan 421001, P.R. China
| | - Meng-Ying Tang
- Department of Infectious Diseases, The First Affiliated Hospital of The University of South China, Hengyang, Hunan 421001, P.R. China
| | - Tao Ma
- Department of Infectious Diseases, The First Affiliated Hospital of The University of South China, Hengyang, Hunan 421001, P.R. China
| | - Hua Peng
- Department of Infectious Diseases, The First Affiliated Hospital of The University of South China, Hengyang, Hunan 421001, P.R. China
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19
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Wang NY, Xu Y, Zuo WQ, Xiao KJ, Liu L, Zeng XX, You XY, Zhang LD, Gao C, Liu ZH, Ye TH, Xia Y, Xiong Y, Song XJ, Lei Q, Peng CT, Tang H, Yang SY, Wei YQ, Yu LT. Discovery of imidazo[2,1-b]thiazole HCV NS4B inhibitors exhibiting synergistic effect with other direct-acting antiviral agents. J Med Chem 2015; 58:2764-78. [PMID: 25710739 DOI: 10.1021/jm501934n] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The design, synthesis, and SAR studies of novel inhibitors of HCV NS4B based on the imidazo[2,1-b]thiazole scaffold were described. Optimization of potency with respect to genotype 1b resulted in the discovery of two potent leads 26f (EC50 = 16 nM) and 28g (EC50 = 31 nM). The resistance profile studies revealed that 26f and 28g targeted HCV NS4B, more precisely the second amphipathic α helix of NS4B (4BAH2). Cross-resistance between our 4BAH2 inhibitors and other direct-acting antiviral agents targeting NS3/4A, NS5A, and NS5B was not observed. For the first time, the synergism of a series of combinations based on 4BAH2 inhibitors was evaluated. The results demonstrated that our 4BAH2 inhibitor 26f was synergistic with NS3/4A inhibitor simeprevir, NS5A inhibitor daclatasvir, and NS5B inhibitor sofosbuvir, and it could also reduce the dose of these drugs at almost all effect levels. Our study suggested that favorable effects could be achieved by combining 4BAH2 inhibitors such as 26f with these approved drugs and that new all-oral antiviral combinations based on 4BAH2 inhibitors were worth developing to supplement or even replace current treatment regimens for curing HCV infection.
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Affiliation(s)
- Ning-Yu Wang
- §State Key Laboratory of Biotherapy/Collaborative Innovation Center for Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041, China
| | - Ying Xu
- §State Key Laboratory of Biotherapy/Collaborative Innovation Center for Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041, China
| | - Wei-Qiong Zuo
- §State Key Laboratory of Biotherapy/Collaborative Innovation Center for Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041, China
| | - Kun-Jie Xiao
- §State Key Laboratory of Biotherapy/Collaborative Innovation Center for Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041, China
| | - Li Liu
- §State Key Laboratory of Biotherapy/Collaborative Innovation Center for Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041, China.,‡Department of Pharmaceutical and Bioengineering, School of Chemical Engineering, Sichuan University, Chengdu, Sichuan 610065, China
| | - Xiu-Xiu Zeng
- §State Key Laboratory of Biotherapy/Collaborative Innovation Center for Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041, China.,‡Department of Pharmaceutical and Bioengineering, School of Chemical Engineering, Sichuan University, Chengdu, Sichuan 610065, China
| | - Xin-Yu You
- §State Key Laboratory of Biotherapy/Collaborative Innovation Center for Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041, China.,‡Department of Pharmaceutical and Bioengineering, School of Chemical Engineering, Sichuan University, Chengdu, Sichuan 610065, China
| | - Li-Dan Zhang
- §State Key Laboratory of Biotherapy/Collaborative Innovation Center for Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041, China.,‡Department of Pharmaceutical and Bioengineering, School of Chemical Engineering, Sichuan University, Chengdu, Sichuan 610065, China
| | - Chao Gao
- §State Key Laboratory of Biotherapy/Collaborative Innovation Center for Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041, China
| | - Zhi-Hao Liu
- §State Key Laboratory of Biotherapy/Collaborative Innovation Center for Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041, China
| | - Ting-Hong Ye
- §State Key Laboratory of Biotherapy/Collaborative Innovation Center for Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041, China
| | - Yong Xia
- §State Key Laboratory of Biotherapy/Collaborative Innovation Center for Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041, China
| | - Ying Xiong
- §State Key Laboratory of Biotherapy/Collaborative Innovation Center for Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041, China
| | - Xue-Jiao Song
- §State Key Laboratory of Biotherapy/Collaborative Innovation Center for Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041, China
| | - Qian Lei
- §State Key Laboratory of Biotherapy/Collaborative Innovation Center for Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041, China
| | - Cui-Ting Peng
- §State Key Laboratory of Biotherapy/Collaborative Innovation Center for Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041, China.,‡Department of Pharmaceutical and Bioengineering, School of Chemical Engineering, Sichuan University, Chengdu, Sichuan 610065, China
| | - Hong Tang
- §State Key Laboratory of Biotherapy/Collaborative Innovation Center for Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041, China
| | - Sheng-Yong Yang
- §State Key Laboratory of Biotherapy/Collaborative Innovation Center for Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041, China
| | - Yu-Quan Wei
- §State Key Laboratory of Biotherapy/Collaborative Innovation Center for Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041, China
| | - Luo-Ting Yu
- §State Key Laboratory of Biotherapy/Collaborative Innovation Center for Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041, China
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20
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6-(Azaindol-2-yl)pyridine-3-sulfonamides as potent and selective inhibitors targeting hepatitis C virus NS4B. Bioorg Med Chem Lett 2015; 25:781-6. [PMID: 25613678 DOI: 10.1016/j.bmcl.2014.12.093] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Revised: 12/23/2014] [Accepted: 12/29/2014] [Indexed: 12/16/2022]
Abstract
A structure-activity relationship investigation of various 6-(azaindol-2-yl)pyridine-3-sulfonamides using the HCV replicon cell culture assay led to the identification of a potent series of 7-azaindoles that target the hepatitis C virus NS4B. Compound 2ac, identified via further optimization of the series, has excellent potency against the HCV 1b replicon with an EC50 of 2nM and a selectivity index of >5000 with respect to cellular GAPDH RNA. Compound 2ac also has excellent oral plasma exposure levels in rats, dogs and monkeys and has a favorable liver to plasma distribution profile in rats.
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21
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In vitro antiviral activity and preclinical and clinical resistance profile of miravirsen, a novel anti-hepatitis C virus therapeutic targeting the human factor miR-122. Antimicrob Agents Chemother 2014; 59:599-608. [PMID: 25385103 DOI: 10.1128/aac.04220-14] [Citation(s) in RCA: 163] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Miravirsen is a β-D-oxy-locked nucleic acid-modified phosphorothioate antisense oligonucleotide targeting the liver-specific microRNA-122 (miR-122). Miravirsen demonstrated antiviral activity against hepatitis C virus (HCV) genotype 1b replicons with a mean 50% effective concentration (EC50) of 0.67 μM. No cytotoxicity was observed up to the highest concentration tested (>320 μM) in different cell culture models, yielding a therapeutic index of ≥ 297. Combination studies of miravirsen with interferon α2b, ribavirin, and nonnucleoside (VX-222) and nucleoside (2'-methylcytidine) inhibitors of NS5B, NS5A (BMS-790052), or NS3 (telaprevir) indicated additive interactions. Miravirsen demonstrated broad antiviral activity when tested against HCV replicons resistant to NS3, NS5A, and NS5B inhibitors with less than 2-fold reductions in susceptibility. In serial passage studies, an A4C nucleotide change was observed in the HCV 5' untranslated region (UTR) from cells passaged in the presence of up to 20 μM (40-fold the miravirsen EC50 concentration) at day 72 of passage but not at earlier time points (up to 39 days of passage). Likewise, a C3U nucleotide change was observed in the HCV 5'UTR from subjects with viral rebound after the completion of therapy in a miravirsen phase 2 clinical trial. An HCV variant constructed to contain the A4C change was fully susceptible to miravirsen. A C3U HCV variant demonstrated overall reductions in susceptibility to miravirsen but was fully susceptible to all other anti-HCV agents tested. In summary, miravirsen has demonstrated broad antiviral activity and a relatively high genetic barrier to resistance. The identification of nucleotide changes associated with miravirsen resistance should help further elucidate the biology of miR-122 interactions with HCV. (The clinical trial study has been registered at ClinicalTrials.gov under registration no. NCT01200420).
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22
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Maringer K, Fernandez-Sesma A. Message in a bottle: lessons learned from antagonism of STING signalling during RNA virus infection. Cytokine Growth Factor Rev 2014; 25:669-79. [PMID: 25212897 PMCID: PMC4330990 DOI: 10.1016/j.cytogfr.2014.08.004] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Accepted: 08/05/2014] [Indexed: 02/08/2023]
Abstract
STING has emerged in recent years as an important signalling adaptor in the activation of type I interferon responses during infection with DNA viruses and bacteria. An increasing body of evidence suggests that STING also modulates responses to RNA viruses, though the mechanisms remain less clear. In this review, we give a brief overview of the ways in which STING facilitates sensing of RNA viruses. These include modulation of RIG-I-dependent responses through STING's interaction with MAVS, and more speculative mechanisms involving the DNA sensor cGAS and sensing of membrane remodelling events. We then provide an in-depth literature review to summarise the known mechanisms by which RNA viruses of the families Flaviviridae and Coronaviridae evade sensing through STING. Our own work has shown that the NS2B/3 protease complex of the flavivirus dengue virus binds and cleaves STING, and that an inability to degrade murine STING may contribute to host restriction in this virus. We contrast this to the mechanism employed by the distantly related hepacivirus hepatitis C virus, in which STING is bound and inactivated by the NS4B protein. Finally, we discuss STING antagonism in the coronaviruses SARS coronavirus and human coronavirus NL63, which disrupt K63-linked polyubiquitination and dimerisation of STING (both of which are required for STING-mediated activation of IRF-3) via their papain-like proteases. We draw parallels with less-well characterised mechanisms of STING antagonism in related viruses, and place our current knowledge in the context of species tropism restrictions that potentially affect the emergence of new human pathogens.
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Affiliation(s)
- Kevin Maringer
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; School of Cellular and Molecular Medicine, School of Medical Sciences, University of Bristol, Bristol BS8 1TD, United Kingdom
| | - Ana Fernandez-Sesma
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.
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23
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Design and synthesis of spirocyclic compounds as HCV replication inhibitors by targeting viral NS4B protein. Bioorg Med Chem Lett 2014; 24:2288-94. [DOI: 10.1016/j.bmcl.2014.03.080] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Revised: 03/22/2014] [Accepted: 03/25/2014] [Indexed: 12/19/2022]
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24
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Statistical linkage analysis of substitutions in patient-derived sequences of genotype 1a hepatitis C virus nonstructural protein 3 exposes targets for immunogen design. J Virol 2014; 88:7628-44. [PMID: 24760894 DOI: 10.1128/jvi.03812-13] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
UNLABELLED Chronic hepatitis C virus (HCV) infection is one of the leading causes of liver failure and liver cancer, affecting around 3% of the world's population. The extreme sequence variability of the virus resulting from error-prone replication has thwarted the discovery of a universal prophylactic vaccine. It is known that vigorous and multispecific cellular immune responses, involving both helper CD4(+) and cytotoxic CD8(+) T cells, are associated with the spontaneous clearance of acute HCV infection. Escape mutations in viral epitopes can, however, abrogate protective T-cell responses, leading to viral persistence and associated pathologies. Despite the propensity of the virus to mutate, there might still exist substitutions that incur a fitness cost. In this paper, we identify groups of coevolving residues within HCV nonstructural protein 3 (NS3) by analyzing diverse sequences of this protein using ideas from random matrix theory and associated methods. Our analyses indicate that one of these groups comprises a large percentage of residues for which HCV appears to resist multiple simultaneous substitutions. Targeting multiple residues in this group through vaccine-induced immune responses should either lead to viral recognition or elicit escape substitutions that compromise viral fitness. Our predictions are supported by published clinical data, which suggested that immune genotypes associated with spontaneous clearance of HCV preferentially recognized and targeted this vulnerable group of residues. Moreover, mapping the sites of this group onto the available protein structure provided insight into its functional significance. An epitope-based immunogen is proposed as an alternative to the NS3 epitopes in the peptide-based vaccine IC41. IMPORTANCE Despite much experimental work on HCV, a thorough statistical study of the HCV sequences for the purpose of immunogen design was missing in the literature. Such a study is vital to identify epistatic couplings among residues that can provide useful insights for designing a potent vaccine. In this work, ideas from random matrix theory were applied to characterize the statistics of substitutions within the diverse publicly available sequences of the genotype 1a HCV NS3 protein, leading to a group of sites for which HCV appears to resist simultaneous substitutions possibly due to deleterious effect on viral fitness. Our analysis leads to completely novel immunogen designs for HCV. In addition, the NS3 epitopes used in the recently proposed peptide-based vaccine IC41 were analyzed in the context of our framework. Our analysis predicts that alternative NS3 epitopes may be worth exploring as they might be more efficacious.
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Identification of AP80978, a novel small-molecule inhibitor of hepatitis C virus replication that targets NS4B. Antimicrob Agents Chemother 2014; 58:3399-410. [PMID: 24709254 DOI: 10.1128/aac.00113-14] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
A small-molecule inhibitor of hepatitis C virus (HCV) designated AP89652 was identified by screening a compound library with an HCV genotype 1b subgenomic replicon assay. AP89652 contains two chiral centers, and testing of two syn enantiomers revealed that activity in the replicon assay resided with only one, AP80978, whose 50% effective concentration (EC50) (the concentration at which a 50% reduction in Renilla luciferase levels was observed relative to an untreated control) was 630 nM. AP80978 was inhibitory against HCV genotypes 1a and 1b but not genotype 2a. In a replicon clearance assay, the potency and clearance rate of AP80978 were similar to those of telaprevir (VX950) and cyclosporine (CsA). AP80978 was nontoxic when tested against a panel of human cell lines, and inhibitory activity was HCV specific in that there was limited activity against negative-strand viruses, an alphavirus, and flaviviruses. By selection of resistant replicons and assessment of activity in genotype 1b/2a intergenotypic replicons, the viral protein target of this compound was identified as NS4B. NS4B F98V/L substitutions were confirmed by site-directed mutagenesis as AP80978 resistance-associated mutations. When tested against HCV produced in cell culture, the compound was significantly more potent than other HCV inhibitors, including VX950, CsA, and 2'-C-methyladenosine (2'C-meA). In addition, AP80977, the enantiomer that was inactive in the replicon assay, had activity against the virus, although it was lower than the activity of AP80978. These results suggest that AP80978 has the potential to be optimized into an effective antiviral drug and is a useful tool to further study the role of NS4B in HCV replication.
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26
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Zhang N, Zhang X, Zhu J, Turpoff A, Chen G, Morrill C, Huang S, Lennox W, Kakarla R, Liu R, Li C, Ren H, Almstead N, Venkatraman S, Njoroge FG, Gu Z, Clausen V, Graci J, Jung SP, Zheng Y, Colacino JM, Lahser F, Sheedy J, Mollin A, Weetall M, Nomeir A, Karp GM. Structure-activity relationship (SAR) optimization of 6-(indol-2-yl)pyridine-3-sulfonamides: identification of potent, selective, and orally bioavailable small molecules targeting hepatitis C (HCV) NS4B. J Med Chem 2013; 57:2121-35. [PMID: 24266880 DOI: 10.1021/jm401621g] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
A novel, potent, and orally bioavailable inhibitor of hepatitis C RNA replication targeting NS4B, compound 4t (PTC725), has been identified through chemical optimization of the 6-(indol-2-yl)pyridine-3-sulfonamide 2 to improve DMPK and safety properties. The focus of the SAR investigations has been to identify the optimal combination of substituents at the indole N-1, C-5, and C-6 positions and the sulfonamide group to limit the potential for in vivo oxidative metabolism and to achieve an acceptable pharmacokinetic profile. Compound 4t has excellent potency against the HCV 1b replicon, with an EC50 = 2 nM and a selectivity index of >5000 with respect to cellular GAPDH. Compound 4t has an overall favorable pharmacokinetic profile with oral bioavailability values of 62%, 78%, and 18% in rats, dogs, and monkeys, respectively, as well as favorable tissue distribution properties with a liver to plasma exposure ratio of 25 in rats.
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Affiliation(s)
- Nanjing Zhang
- PTC Therapeutics, Inc. , 100 Corporate Court, South Plainfield, New Jersey 07080, United States
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27
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Watashi K. Antiviral agents for analyzing virus life cycle: chemical genetics for virology. YAKUGAKU ZASSHI 2013; 133:1169-75. [PMID: 24189558 DOI: 10.1248/yakushi.13-00212-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Hepatitis C virus, which affects approximately 170 million people worldwide, is a major causative agent of hepatocellular carcinoma. Anti-HCV treatment is available with the combination of pegylated interferon and ribavirin, and newly approved protease inhibitors. However, because of the diverse anti-HCV efficacy among HCV genotypes and significant side effects, alternative anti-HCV agents are in great demand. Using cell-based systems supporting a part of or the whole HCV life cycle, we identified cyclosporin A, tamoxifen, and benzamide derivatives that inhibited the replication of HCV RNA or the production of infectious HCV particles. In this article, we summarize the mechanistic analyses of the HCV life cycle using these small molecules. Thus, chemical genetics is a powerful approach for revealing molecular mechanisms of the viral life cycle as well as for developing new antiviral agents.
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Affiliation(s)
- Koichi Watashi
- Department of Virology II, National Institute of Infectious Diseases
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28
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Rajyaguru S, Yang H, Martin R, Miller MD, Mo H. Development and characterization of a replicon-based phenotypic assay for assessing HCV NS4B from clinical isolates. Antiviral Res 2013; 100:328-36. [PMID: 24013002 DOI: 10.1016/j.antiviral.2013.08.022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2012] [Revised: 08/23/2013] [Accepted: 08/25/2013] [Indexed: 01/10/2023]
Abstract
The hepatitis C virus (HCV) NS4B inhibitors have shown potent inhibition of HCV replication in vitro. To assess the effect of viral diversity on the susceptibility to NS4B inhibitors, genotype (GT)-specific GT1a and GT1b replicon shuttle vectors were designed and created for cloning HCV NS4B genes from clinical isolates. For the GT1b NS4B shuttle vector, the S2204I adaptive mutation was introduced in NS5A to improve replication due to the replacement of the K1846T adaptive mutation in NS4B with NS4B from the clinical isolates. In addition to the adaptive mutations, a newly identified Huh-7 cell line, Huh-7-1C, which is highly permissive for both GT1a and GT1b replication, was used to further enhance the replication levels. HCV NS4B gene from clinical isolates was amplified and inserted into the corresponding GT1a and GT1b modified lab strain chimeric replicons. GT1a and GT1b chimeric replicons expressing diverse NS4B genes from corresponding subtypes of clinical isolates replicated at highly efficient levels for phenotypic analysis. Due to natural variation in their amino acid residues in NS4B, these isolates displayed varying drug susceptibilities to an NS4B inhibitor. In mixed populations with wild-type, the sensitivity of resistance detection of NS4B resistant mutants H94R and V105M was between 20% and 80%. The chimeric shuttle vectors can be used to characterize the activity of antiviral drugs targeting NS4B from diverse natural clinical isolates and aid in the development of novel compounds against HCV NS4B.
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Affiliation(s)
- Sonal Rajyaguru
- Gilead Sciences Inc, 333 Lakeside Drive, Foster City, CA 94404, United States
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29
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Moradpour D, Penin F. Hepatitis C virus proteins: from structure to function. Curr Top Microbiol Immunol 2013; 369:113-42. [PMID: 23463199 DOI: 10.1007/978-3-642-27340-7_5] [Citation(s) in RCA: 149] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Great progress has been made over the past years in elucidating the structure and function of the hepatitis C virus (HCV) proteins, most of which are now actively being pursued as antiviral targets. The structural proteins, which form the viral particle, include the core protein and the envelope glycoproteins E1 and E2. The nonstructural proteins include the p7 viroporin, the NS2 protease, the NS3-4A complex harboring protease and NTPase/RNA helicase activities, the NS4B and NS5A proteins, and the NS5B RNA-dependent RNA polymerase. NS4B is a master organizer of replication complex formation while NS5A is a zinc-containing phosphoprotein involved in the regulation of HCV RNA replication versus particle production. Core to NS2 make up the assembly module while NS3 to NS5B represent the replication module (replicase). However, HCV proteins exert multiple functions during the viral life cycle, and these may be governed by different structural conformations and/or interactions with viral and/or cellular partners. Remarkably, each viral protein is anchored to intracellular membranes via specific determinants that are essential to protein function in the cell. This review summarizes current knowledge of the structure and function of the HCV proteins and highlights recent advances in the field.
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Affiliation(s)
- Darius Moradpour
- Centre Hospitalier Universitaire Vaudois, University of Lausanne, Lausanne, Switzerland.
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30
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Zhang X, Zhang N, Chen G, Turpoff A, Ren H, Takasugi J, Morrill C, Zhu J, Li C, Lennox W, Paget S, Liu Y, Almstead N, George Njoroge F, Gu Z, Komatsu T, Clausen V, Espiritu C, Graci J, Colacino J, Lahser F, Risher N, Weetall M, Nomeir A, Karp GM. Discovery of novel HCV inhibitors: Synthesis and biological activity of 6-(indol-2-yl)pyridine-3-sulfonamides targeting hepatitis C virus NS4B. Bioorg Med Chem Lett 2013; 23:3947-53. [DOI: 10.1016/j.bmcl.2013.04.049] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2013] [Revised: 04/12/2013] [Accepted: 04/22/2013] [Indexed: 12/27/2022]
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31
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Scheel TKH, Rice CM. Understanding the hepatitis C virus life cycle paves the way for highly effective therapies. Nat Med 2013; 19:837-49. [PMID: 23836234 PMCID: PMC3984536 DOI: 10.1038/nm.3248] [Citation(s) in RCA: 408] [Impact Index Per Article: 37.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Accepted: 05/28/2013] [Indexed: 02/07/2023]
Abstract
More than two decades of intense research has provided a detailed understanding of hepatitis C virus (HCV), which chronically infects 2% of the world's population. This effort has paved the way for the development of antiviral compounds to spare patients from life-threatening liver disease. An exciting new era in HCV therapy dawned with the recent approval of two viral protease inhibitors, used in combination with pegylated interferon-α and ribavirin; however, this is just the beginning. Multiple classes of antivirals with distinct targets promise highly efficient combinations, and interferon-free regimens with short treatment duration and fewer side effects are the future of HCV therapy. Ongoing and future trials will determine the best antiviral combinations and whether the current seemingly rich pipeline is sufficient for successful treatment of all patients in the face of major challenges, such as HCV diversity, viral resistance, the influence of host genetics, advanced liver disease and other co-morbidities.
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Affiliation(s)
- Troels K H Scheel
- Laboratory of Virology and Infectious Disease, Center for Study of Hepatitis C, The Rockefeller University, New York, New York, USA
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32
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Aghemo A, De Francesco R. New horizons in hepatitis C antiviral therapy with direct-acting antivirals. Hepatology 2013; 58:428-38. [PMID: 23467911 DOI: 10.1002/hep.26371] [Citation(s) in RCA: 131] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2013] [Revised: 02/25/2013] [Accepted: 02/27/2013] [Indexed: 12/19/2022]
Abstract
Most direct-acting antivirals (DAAs) that are being developed as therapy against hepatitis C virus target the NS3/4A protease, the NS5A protein, and the NS5B polymerase. The latter enzyme offers different target sites: the catalytic domain for nucleos(t)ide analogues as well as a number of allosteric sites for nonnucleos(t)ide inhibitors. Two NS3/4A protease inhibitors have been approved recently, and more than 40 new NS3/4A, NS5A, or NS5B inhibitors are in development. These agents can achieve very high cure rates when combined with pegylated interferon-β and ribavirin and show promising clinical results when administered in all-oral combinations. In addition to the more canonical drug targets, new alternative viral targets for small-molecule drug development are emerging, such as p7 or NS4B and viral entry. Future research will need to define well-tolerated and cost-effective DAA combinations that provide the highest rates of viral eradication in all patients (including those with advanced liver disease), the broadest spectrum of action on viral genotypes showing minimal or no clinical resistance, and the shortest treatment duration.
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Affiliation(s)
- Alessio Aghemo
- A.M. e A. Migliavacca Center for the Study of Liver Disease 1st Division of Gastroenterology, Fondazione IRCCS Cá Granda Ospedale Maggiore Policlinico Milan Italy
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33
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Roberts CD, Peat AJ. HCV Replication Inhibitors That Interact with NS4B. SUCCESSFUL STRATEGIES FOR THE DISCOVERY OF ANTIVIRAL DRUGS 2013. [DOI: 10.1039/9781849737814-00111] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
We describe the discovery, development and in vivo activity of small molecules that inhibits HCV replication via direct interaction with the viral NS4B protein. The inhibitors were identified through a phenotypic, cell based, high throughput screen using the HCV subgenomic replicon. Compounds were then optimized to extremely high potency and pharmacokinetics. Mechanistic data generated suggests a hypothesis wherein the compounds described function by binding to NS4B, preventing the formation of the characteristic HCV induced sub‐cellular membranous web required for viral replication. Finally, in vivo proof of mechanism was established by employing a chimeric “humanized” mouse model of HCV infection to demonstrate for the first time that a small molecule with high in vitro affinity for NS4B can inhibit viral replication in vivo.
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Affiliation(s)
- Christopher D. Roberts
- GlaxoSmithKline Research & Development Infectious Diseases Therapeutic Area Unit, 5 Moore Drive, Research Triangle Park, NC 27709 USA
| | - Andrew J. Peat
- GlaxoSmithKline Research & Development Infectious Diseases Therapeutic Area Unit, 5 Moore Drive, Research Triangle Park, NC 27709 USA
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34
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The molecular and structural basis of advanced antiviral therapy for hepatitis C virus infection. Nat Rev Microbiol 2013; 11:482-96. [PMID: 23748342 DOI: 10.1038/nrmicro3046] [Citation(s) in RCA: 276] [Impact Index Per Article: 25.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The availability of the first molecular clone of the hepatitis C virus (HCV) genome allowed the identification and biochemical characterization of two viral enzymes that are targets for antiviral therapy: the protease NS3-4A and the RNA-dependent RNA polymerase NS5B. With the advent of cell culture systems that can recapitulate either the intracellular steps of the viral replication cycle or the complete cycle, additional drug targets have been identified, most notably the phosphoprotein NS5A, but also host cell factors that promote viral replication, such as cyclophilin A. Here, we review insights into the structures of these proteins and the mechanisms by which they contribute to the HCV replication cycle, and discuss how these insights have facilitated the development of new, directly acting antiviral compounds that have started to enter the clinic.
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35
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Identification of PTC725, an orally bioavailable small molecule that selectively targets the hepatitis C Virus NS4B protein. Antimicrob Agents Chemother 2013; 57:3250-61. [PMID: 23629699 DOI: 10.1128/aac.00527-13] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
While new direct-acting antiviral agents for the treatment of chronic hepatitis C virus (HCV) infection have been approved, there is a continued need for novel antiviral agents that act on new targets and can be used in combination with current therapies to enhance efficacy and to restrict the emergence of drug-resistant viral variants. To this end, we have identified a novel class of small molecules, exemplified by PTC725, that target the nonstructural protein 4B (NS4B). PTC725 inhibited HCV 1b (Con1) replicons with a 50% effective concentration (EC50) of 1.7 nM and an EC90 of 9.6 nM and demonstrated a >1,000-fold selectivity window with respect to cytotoxicity. The compounds were fully active against HCV replicon mutants that are resistant to inhibitors of NS3 protease and NS5B polymerase. Replicons selected for resistance to PTC725 harbored amino acid substitutions F98L/C and V105M in NS4B. Anti-replicon activity of PTC725 was additive to synergistic in combination with alpha interferon or with inhibitors of HCV protease and polymerase. Immunofluorescence microscopy demonstrated that neither the HCV inhibitors nor the F98C substitution altered the subcellular localization of NS4B or NS5A in replicon cells. Oral dosing of PTC725 showed a favorable pharmacokinetic profile with high liver and plasma exposure in mice and rats. Modeling of dosing regimens in humans indicates that a once-per-day or twice-per-day oral dosing regimen is feasible. Overall, the preclinical data support the development of PTC725 for use in the treatment of chronic HCV infection.
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36
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Bozzano F, Marras F, Biassoni R, De Maria A. Natural killer cells in hepatitis C virus infection. Expert Rev Clin Immunol 2013; 8:775-88. [PMID: 23167689 DOI: 10.1586/eci.12.71] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Hepatitis C virus (HCV) infection induces the long-term risk of liver cirrhosis or hepatocellular carcinoma and in adults represents the most common cause of liver transplantation. Natural killer (NK) cells participate in innate immune responses with efficient direct antitumor and antiviral defense. Over the years, their complex interaction with downstream adaptive responses and with the regulation of immune responses has been increasingly recognized. Considerable advances have been made particularly in understanding the role of NK cells in the pathophysiology of HCV infection and their possible use as biological markers for clinical purposes. This review summarizes the available data on the role of NK cells in the natural history of HCV infection and their role in the outcome of treatment. The main objective of this review is to summarize recent advancements in the basic understanding of NK cell function highlighting their possible translational use in clinical practice. An integrated practical view on the possible use of currently available predictive immunogenetic and NK cell functional tests is provided, to support clinical management choices for optimal treatment of patients with both standard and new drug regimens.
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Affiliation(s)
- Federica Bozzano
- Center of Excellence for Biomedical Research, University of Genova, Genova, Italy
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37
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Miller JF, Chong PY, Shotwell JB, Catalano JG, Tai VWF, Fang J, Banka AL, Roberts CD, Youngman M, Zhang H, Xiong Z, Mathis A, Pouliot JJ, Hamatake RK, Price DJ, Seal JW, Stroup LL, Creech KL, Carballo LH, Todd D, Spaltenstein A, Furst S, Hong Z, Peat AJ. Hepatitis C Replication Inhibitors That Target the Viral NS4B Protein. J Med Chem 2013; 57:2107-20. [DOI: 10.1021/jm400125h] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- John F. Miller
- GlaxoSmithKline Research and Development, 5 Moore Drive, Research Triangle Park,
North Carolina 27709, United States
| | - Pek Y. Chong
- GlaxoSmithKline Research and Development, 5 Moore Drive, Research Triangle Park,
North Carolina 27709, United States
| | - J. Brad Shotwell
- GlaxoSmithKline Research and Development, 5 Moore Drive, Research Triangle Park,
North Carolina 27709, United States
| | - John G. Catalano
- GlaxoSmithKline Research and Development, 5 Moore Drive, Research Triangle Park,
North Carolina 27709, United States
| | - Vincent W.-F. Tai
- GlaxoSmithKline Research and Development, 5 Moore Drive, Research Triangle Park,
North Carolina 27709, United States
| | - Jing Fang
- GlaxoSmithKline Research and Development, 5 Moore Drive, Research Triangle Park,
North Carolina 27709, United States
| | - Anna L. Banka
- GlaxoSmithKline Research and Development, 5 Moore Drive, Research Triangle Park,
North Carolina 27709, United States
| | - Christopher D. Roberts
- GlaxoSmithKline Research and Development, 5 Moore Drive, Research Triangle Park,
North Carolina 27709, United States
| | - Michael Youngman
- GlaxoSmithKline Research and Development, 5 Moore Drive, Research Triangle Park,
North Carolina 27709, United States
| | - Huichang Zhang
- GlaxoSmithKline Research and Development, 5 Moore Drive, Research Triangle Park,
North Carolina 27709, United States
| | - Zhiping Xiong
- GlaxoSmithKline Research and Development, 5 Moore Drive, Research Triangle Park,
North Carolina 27709, United States
| | - Amanda Mathis
- GlaxoSmithKline Research and Development, 5 Moore Drive, Research Triangle Park,
North Carolina 27709, United States
| | - Jeffery J. Pouliot
- GlaxoSmithKline Research and Development, 5 Moore Drive, Research Triangle Park,
North Carolina 27709, United States
| | - Robert K. Hamatake
- GlaxoSmithKline Research and Development, 5 Moore Drive, Research Triangle Park,
North Carolina 27709, United States
| | - Daniel J. Price
- GlaxoSmithKline Research and Development, 5 Moore Drive, Research Triangle Park,
North Carolina 27709, United States
| | - John W. Seal
- GlaxoSmithKline Research and Development, 5 Moore Drive, Research Triangle Park,
North Carolina 27709, United States
| | - Lisa L. Stroup
- GlaxoSmithKline Research and Development, 5 Moore Drive, Research Triangle Park,
North Carolina 27709, United States
| | - Katrina L. Creech
- GlaxoSmithKline Research and Development, 5 Moore Drive, Research Triangle Park,
North Carolina 27709, United States
| | - Luz H. Carballo
- GlaxoSmithKline Research and Development, 5 Moore Drive, Research Triangle Park,
North Carolina 27709, United States
| | - Dan Todd
- GlaxoSmithKline Research and Development, 5 Moore Drive, Research Triangle Park,
North Carolina 27709, United States
| | - Andrew Spaltenstein
- GlaxoSmithKline Research and Development, 5 Moore Drive, Research Triangle Park,
North Carolina 27709, United States
| | - Sylvia Furst
- GlaxoSmithKline Research and Development, 5 Moore Drive, Research Triangle Park,
North Carolina 27709, United States
| | - Zhi Hong
- GlaxoSmithKline Research and Development, 5 Moore Drive, Research Triangle Park,
North Carolina 27709, United States
| | - Andrew J. Peat
- GlaxoSmithKline Research and Development, 5 Moore Drive, Research Triangle Park,
North Carolina 27709, United States
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38
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Gu M, Rice CM. Structures of hepatitis C virus nonstructural proteins required for replicase assembly and function. Curr Opin Virol 2013; 3:129-36. [PMID: 23601958 DOI: 10.1016/j.coviro.2013.03.013] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Revised: 03/08/2013] [Accepted: 03/20/2013] [Indexed: 02/07/2023]
Abstract
Approximately 3% of the world population is infected with hepatitis C virus (HCV), causing a serious public health burden. Like other positive-strand RNA viruses, HCV assembles replicase complexes in association with cellular membranes and produces progeny RNA genomes through negative-strand intermediates. The viral proteins required for RNA replication are nonstructural (NS) proteins NS3 to NS5B. Owing to many obstacles and limitations in structural characterization of proteins and complexes with multiple transmembrane segments, attempts to understand the assembly and action of the HCV replicase complex have been challenging. Nevertheless, great progress has been made in obtaining structural information for several replicase components, providing insights into some aspects of the viral genome replication machinery.
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Affiliation(s)
- Meigang Gu
- Center for the Study of Hepatitis C, Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY 10065, United States.
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39
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Kong L, Li S, Liao Q, Zhang Y, Sun R, Zhu X, Zhang Q, Wang J, Wu X, Fang X, Zhu Y. Oleanolic acid and ursolic acid: novel hepatitis C virus antivirals that inhibit NS5B activity. Antiviral Res 2013; 98:44-53. [PMID: 23422646 DOI: 10.1016/j.antiviral.2013.02.003] [Citation(s) in RCA: 102] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2012] [Revised: 01/10/2013] [Accepted: 02/08/2013] [Indexed: 12/01/2022]
Abstract
Hepatitis C virus (HCV) infects up to 170 million people worldwide and causes significant morbidity and mortality. Unfortunately, current therapy is only curative in approximately 50% of HCV patients and has adverse side effects, which warrants the need to develop novel and effective antivirals against HCV. We have previously reported that the Chinese herb Fructus Ligustri Lucidi (FLL) directly inhibited HCV NS5B RNA-dependent RNA polymerase (RdRp) activity (Kong et al., 2007). In this study, we found that the FLL aqueous extract strongly suppressed HCV replication. Further high-performance liquid chromatography (HPLC) analysis combined with inhibitory assays indicates that oleanolic acid and ursolic acid are two antiviral components within FLL aqueous extract that significantly suppressed the replication of HCV genotype 1b replicon and HCV genotype 2a JFH1 virus. Moreover, oleanolic acid and ursolic acid exhibited anti-HCV activity at least partly through suppressing HCV NS5B RdRp activity as noncompetitive inhibitors. Therefore, our results for the first time demonstrated that natural products oleanolic acid and ursolic acid could be used as potential HCV antivirals that can be applied to clinic trials either as monotherapy or in combination with other HCV antivirals.
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Affiliation(s)
- Lingbao Kong
- College of Bioscience and Engineering, Jiangxi Agricultural University, Nanchang, Jiangxi 330045, China.
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40
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Nitta S, Sakamoto N, Nakagawa M, Kakinuma S, Mishima K, Kusano-Kitazume A, Kiyohashi K, Murakawa M, Nishimura-Sakurai Y, Azuma S, Tasaka-Fujita M, Asahina Y, Yoneyama M, Fujita T, Watanabe M. Hepatitis C virus NS4B protein targets STING and abrogates RIG-I-mediated type I interferon-dependent innate immunity. Hepatology 2013; 57:46-58. [PMID: 22911572 DOI: 10.1002/hep.26017] [Citation(s) in RCA: 115] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2011] [Accepted: 07/24/2012] [Indexed: 12/20/2022]
Abstract
UNLABELLED Hepatitis C virus (HCV) infection blocks cellular interferon (IFN)-mediated antiviral signaling through cleavage of Cardif by HCV-NS3/4A serine protease. Like NS3/4A, NS4B protein strongly blocks IFN-β production signaling mediated by retinoic acid-inducible gene I (RIG-I); however, the underlying molecular mechanisms are not well understood. Recently, the stimulator of interferon genes (STING) was identified as an activator of RIG-I signaling. STING possesses a structural homology domain with flaviviral NS4B, which suggests a direct protein-protein interaction. In the present study, we investigated the molecular mechanisms by which NS4B targets RIG-I-induced and STING-mediated IFN-β production signaling. IFN-β promoter reporter assay showed that IFN-β promoter activation induced by RIG-I or Cardif was significantly suppressed by both NS4B and NS3/4A, whereas STING-induced IFN-β activation was suppressed by NS4B but not by NS3/4A, suggesting that NS4B had a distinct point of interaction. Immunostaining showed that STING colocalized with NS4B in the endoplasmic reticulum. Immunoprecipitation and bimolecular fluorescence complementation (BiFC) assays demonstrated that NS4B specifically bound STING. Intriguingly, NS4B expression blocked the protein interaction between STING and Cardif, which is required for robust IFN-β activation. NS4B truncation assays showed that its N terminus, containing the STING homology domain, was necessary for the suppression of IFN-β promoter activation. NS4B suppressed residual IFN-β activation by an NS3/4A-cleaved Cardif (Cardif1-508), suggesting that NS3/4A and NS4B may cooperate in the blockade of IFN-β production. CONCLUSION NS4B suppresses RIG-I-mediated IFN-β production signaling through a direct protein interaction with STING. Disruption of that interaction may restore cellular antiviral responses and may constitute a novel therapeutic strategy for the eradication of HCV.
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Affiliation(s)
- Sayuri Nitta
- Department of Gastroenterology and Hepatology, Tokyo Medical and Dental University, Tokyo, Japan
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41
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Delang L, Neyts J, Vliegen I, Abrignani S, Neddermann P, De Francesco R. Hepatitis C Virus-Specific Directly Acting Antiviral Drugs. Curr Top Microbiol Immunol 2013; 369:289-320. [DOI: 10.1007/978-3-642-27340-7_12] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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42
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Kanwal N, Zaidi NUSS, Gomez MK. Non-structural protein NS4B: HCV replication web inducer. ASIAN PACIFIC JOURNAL OF TROPICAL DISEASE 2012. [DOI: 10.1016/s2222-1808(12)60111-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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43
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Welker MW, Susser S, Welsch C, Perner D, Füller C, Kronenberger B, Herrmann E, Zeuzem S, Sarrazin C. Modulation of replication efficacy of the hepatitis C virus replicon Con1 by site-directed mutagenesis of an NS4B aminoterminal basic leucine zipper. J Viral Hepat 2012; 19:775-83. [PMID: 23043384 DOI: 10.1111/j.1365-2893.2012.01605.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The hepatitis C virus (HCV) nonstructural protein 4B (NS4B) is assumed to function as a membrane anchor and protein hub for the viral replication complex. The aim of the current work was to modulate HCV replication efficacy in the subgenomic Con1 replicon by mutations of specific sites within the aminoterminal-located basic leucine zipper (bZIP), a candidate motif for protein-protein interactions involving NS4B. Mutational sites and amino acid substitutes were determined by in-silico sequence analyses of the NS4B-bZIP motif in 357 isolates of HCV genotype 1b from the euHCVdB and LosAlamos database and consecutive analysis of conserved physico-chemical properties at bZIP specific positions. Mutants with predicted minor, medium or major reduction of replication efficacy were tested in the pFKI389neo/NS3-3'/ET plasmid replicon model. Four sites (L25, T29, V39 and W43) of crucial importance for bZIP-mediated protein interaction with predicted apolarity of respective amino acid positions were selected for mutational studies. Substitutes with physico-chemical properties matching the predicted requirements either well (T29A), moderately (L25W, V39W), or insufficiently (T29E, W43E) were associated with slightly improved, moderate and marked decreased replication efficacy, respectively. Spontaneous (T29G) and adaptive (A28G, E40G) mutations occurred in the T29E mutation isolate only and were associated with marked reduction of replication efficacy. The bZIP motif region of NS4B is crucial for RNA replication in the subgenomic Con1 replicon system. RNA replication efficacy can be modulated by site-directed mutagenesis at specific bZIP functional sites. New adaptive amino acid mutations were identified within the HCV NS4B protein.
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Affiliation(s)
- M-W Welker
- Klinikum der Johann Wolfgang Goethe-Universität, Medizinische Klinik, Theodor-Stern-Kai, Frankfurt am Main, Germany
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Shotwell JB, Baskaran S, Chong P, Creech KL, Crosby RM, Dickson H, Fang J, Garrido D, Mathis A, Maung J, Parks DJ, Pouliot JJ, Price DJ, Rai R, Seal JW, Schmitz U, Tai VWF, Thomson M, Xie M, Xiong ZZ, Peat AJ. Imidazo[1,2-a]pyridines That Directly Interact with Hepatitis C NS4B: Initial Preclinical Characterization. ACS Med Chem Lett 2012; 3:565-9. [PMID: 24900511 DOI: 10.1021/ml300090x] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2012] [Accepted: 05/24/2012] [Indexed: 11/30/2022] Open
Abstract
A series of imidazo[1,2-a]pyridines which directly bind to HCV Non-Structural Protein 4B (NS4B) is described. This series demonstrates potent in vitro inhibition of HCV replication (EC50 < 10 nM), direct binding to purified NS4B protein (IC50 < 20 nM), and an HCV resistance pattern associated with NS4B (H94N/R, V105L/M, F98L) that are unique among reported HCV clinical assets, suggestive of the potential for additive or synergistic combination with other small molecule inhibitors of HCV replication.
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Affiliation(s)
- J. Brad Shotwell
- GlaxoSmithKline, Antiviral Discovery Performance
Unit, 5 Moore Drive, Research Triangle
Park, North Carolina 27709-3398, United States
| | - Subramanian Baskaran
- GlaxoSmithKline, Antiviral Discovery Performance
Unit, 5 Moore Drive, Research Triangle
Park, North Carolina 27709-3398, United States
| | - Pek Chong
- GlaxoSmithKline, Antiviral Discovery Performance
Unit, 5 Moore Drive, Research Triangle
Park, North Carolina 27709-3398, United States
| | - Katrina L. Creech
- GlaxoSmithKline, Platform Technology and Science, 5 Moore Drive, Research Triangle
Park, North Carolina 27709-3398, United States
| | - Renae M. Crosby
- GlaxoSmithKline, Antiviral Discovery Performance
Unit, 5 Moore Drive, Research Triangle
Park, North Carolina 27709-3398, United States
| | - Hamilton Dickson
- GlaxoSmithKline, Antiviral Discovery Performance
Unit, 5 Moore Drive, Research Triangle
Park, North Carolina 27709-3398, United States
| | - Jing Fang
- GlaxoSmithKline, Antiviral Discovery Performance
Unit, 5 Moore Drive, Research Triangle
Park, North Carolina 27709-3398, United States
| | - Dulce Garrido
- GlaxoSmithKline, Antiviral Discovery Performance
Unit, 5 Moore Drive, Research Triangle
Park, North Carolina 27709-3398, United States
| | - Amanda Mathis
- GlaxoSmithKline, Antiviral Discovery Performance
Unit, 5 Moore Drive, Research Triangle
Park, North Carolina 27709-3398, United States
| | | | - Derek J. Parks
- GlaxoSmithKline, Platform Technology and Science, 5 Moore Drive, Research Triangle
Park, North Carolina 27709-3398, United States
| | - Jeffrey J. Pouliot
- GlaxoSmithKline, Antiviral Discovery Performance
Unit, 5 Moore Drive, Research Triangle
Park, North Carolina 27709-3398, United States
| | - Daniel J. Price
- GlaxoSmithKline, Platform Technology and Science, 5 Moore Drive, Research Triangle
Park, North Carolina 27709-3398, United States
| | | | - John W. Seal
- GlaxoSmithKline, Platform Technology and Science, 5 Moore Drive, Research Triangle
Park, North Carolina 27709-3398, United States
| | | | - Vincent W. F. Tai
- GlaxoSmithKline, Antiviral Discovery Performance
Unit, 5 Moore Drive, Research Triangle
Park, North Carolina 27709-3398, United States
| | - Michael Thomson
- GlaxoSmithKline, Antiviral Discovery Performance
Unit, 5 Moore Drive, Research Triangle
Park, North Carolina 27709-3398, United States
| | - Mi Xie
- GlaxoSmithKline, Antiviral Discovery Performance
Unit, 5 Moore Drive, Research Triangle
Park, North Carolina 27709-3398, United States
| | - Zhiping Z. Xiong
- GlaxoSmithKline, Antiviral Discovery Performance
Unit, 5 Moore Drive, Research Triangle
Park, North Carolina 27709-3398, United States
| | - Andrew J. Peat
- GlaxoSmithKline, Antiviral Discovery Performance
Unit, 5 Moore Drive, Research Triangle
Park, North Carolina 27709-3398, United States
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Li S, Yu X, Guo Y, Kong L. Interaction networks of hepatitis C virus NS4B: implications for antiviral therapy. Cell Microbiol 2012; 14:994-1002. [PMID: 22329740 DOI: 10.1111/j.1462-5822.2012.01773.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Hepatitis C virus (HCV) is an important human pathogen infecting more than 170 million people worldwide with approximately three million new cases each year. HCV depends heavily on interactions between viral proteins and host factors for its survival and propagation. Among HCV viral proteins, the HCV non-structural protein 4B (NS4B) has been shown to mediate virus-host interactions that are essential for HCV replication and pathogenesis and emerged as the target for anti-HCV therapy. Here, we reviewed recent knowledge about the NS4B interaction networks with host factors and its possible regulatory mechanisms, which will both advance our understanding of the role of NS4B in HCV life cycle and illuminate potential viral and host therapeutic targets.
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Affiliation(s)
- Shanshan Li
- Department of Plant Pathology and Microbiology, Iowa State University, Ames, IA, USA
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Fusco DN, Chung RT. Novel Therapies for Hepatitis C: Insights from the Structure of the Virus. Annu Rev Med 2012; 63:373-387. [DOI: 10.1146/annurev-med-042010-085715] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/30/2023]
Abstract
For the first time since the discovery of the hepatitis C virus (HCV), therapeutic options for hepatitis C have expanded. Several agents directly effective against HCV are now in development, including both direct-acting antiviral agents (DAAs) and host cofactor inhibitors. DAAs have been developed to inhibit several HCV proteins, including the NS3/4A serine protease, the NS5B RNA polymerase, NS5A, and NS4B. Host cofactor inhibitors include, but are not limited to, cyclophilin inhibitors, miR122 antagonists, and statins. Development of these agents represents a major advance in HCV therapeutics. This review provides a guide to HCV drugs in various stages of development, including an introduction to their mechanism of action, state of clinical development, efficacy, and side effects.
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Affiliation(s)
- Dahlene N. Fusco
- Gastroenterology Division, Massachusetts General Hospital, Boston, Massachusetts 02114;,
| | - Raymond T. Chung
- Gastroenterology Division, Massachusetts General Hospital, Boston, Massachusetts 02114;,
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El-Shabrawi MHF, Kamal NM. Medical management of chronic liver diseases in children (part I): focus on curable or potentially curable diseases. Paediatr Drugs 2011; 13:357-70. [PMID: 21999649 DOI: 10.2165/11591610-000000000-00000] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The management of children with chronic liver disease (CLD) mandates a multidisciplinary approach. CLDs can be classified into 'potentially' curable, treatable non-curable, and end-stage diseases. Goals pertaining to the management of CLDs can be divided into prevention or minimization of progressive liver damage in curable CLD by treating the primary cause; prevention or control of complications in treatable CLD; and prediction of the outcome in end-stage CLD in order to deliver definitive therapy by surgical procedures, including liver transplantation. Curative, specific therapies aimed at the primary causes of CLDs are, if possible, best considered by a pediatric hepatologist. Medical management of CLDs in children will be reviewed in two parts, with part I (this article) specifically focusing on 'potentially' curable CLDs. Dietary modification is the cornerstone of management for galactosemia, hereditary fructose intolerance, and certain glycogen storage diseases, as well as non-alcoholic steatohepatitis. It is also essential in tyrosinemia, in addition to nitisinone [2-(nitro-4-trifluoromethylbenzoyl)-1,3-cyclohexanedione] therapy, as well as in Wilson disease along with copper-chelating agents such as D-penicillamine, triethylenetetramine dihydrochloride, and ammonium tetrathiomolybdate. Zinc and antioxidants are adjuvant drugs in Wilson disease. New advances in chronic viral hepatitis have been made with the advent of oral antivirals. In children, currently available drugs for the treatment of chronic hepatitis B virus infection are standard interferon (IFN)-α-2, pegylated IFN-α-2 (PG-IFN), and lamivudine. In adults, adefovir and entecavir have also been licensed, whereas telbivudine, emtricitabine, tenofovir disoproxil fumarate, clevudine, and thymosin α-1 are currently undergoing clinical testing. For chronic hepatitis C virus infection, the most accepted treatment is PG-IFN plus ribavirin. Corticosteroids, with or without azathioprine, remain the basic strategy for inducing remission in autoimmune hepatitis. Ciclosporin (cyclosporine) and other immune suppressants may be used for patients who do not achieve remission, or who have significant side effects, with corticosteroid/azathioprine therapy. The above therapies can prevent, or at least minimize, progression of liver damage, particularly if started early, leading to an almost normal quality of life in affected children.
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Conserved GXXXG- and S/T-like motifs in the transmembrane domains of NS4B protein are required for hepatitis C virus replication. J Virol 2011; 85:6464-79. [PMID: 21507970 DOI: 10.1128/jvi.02298-10] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Hepatitis C virus (HCV) nonstructural protein 4B (NS4B) is an integral membrane protein, which plays an important role in the organization and function of the HCV replication complex (RC). Although much is understood about its amphipathic N-terminal and C-terminal domains, we know very little about the role of the transmembrane domains (TMDs) in NS4B function. We hypothesized that in addition to anchoring NS4B into host membranes, the TMDs are engaged in intra- and intermolecular interactions required for NS4B structure/function. To test this hypothesis, we have engineered a chimeric JFH1 genome containing the Con1 NS4B TMD region. The resulting virus titers were greatly reduced from those of JFH1, and further analysis indicated a defect in genome replication. We have mapped this incompatibility to NS4B TMD1 and TMD2 sequences, and we have defined putative TMD dimerization motifs (GXXXG in TMD2 and TMD3; the S/T cluster in TMD1) as key structural/functional determinants. Mutations in each of the putative motifs led to significant decreases in JFH1 replication. Like most of the NS4B chimeras, mutant proteins had no negative impact on NS4B membrane association. However, some mutations led to disruption of NS4B foci, implying that the TMDs play a role in HCV RC formation. Further examination indicated that the loss of NS4B foci correlates with the destabilization of NS4B protein. Finally, we have identified an adaptive mutation in the NS4B TMD2 sequence that has compensatory effects on JFH1 chimera replication. Taken together, these data underscore the functional importance of NS4B TMDs in the HCV life cycle.
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