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Sabariegos R, Albentosa-González L, Palmero B, Clemente-Casares P, Ramírez E, García-Crespo C, Gallego I, de Ávila AI, Perales C, Domingo E, Mas A. Akt Phosphorylation of Hepatitis C Virus NS5B Regulates Polymerase Activity and Hepatitis C Virus Infection. Front Microbiol 2021; 12:754664. [PMID: 34745059 PMCID: PMC8570118 DOI: 10.3389/fmicb.2021.754664] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 09/20/2021] [Indexed: 11/13/2022] Open
Abstract
Hepatitis C virus (HCV) is a single-stranded RNA virus of positive polarity [ssRNA(+)] that replicates its genome through the activity of one of its proteins, called NS5B. This viral protein is responsible for copying the positive-polarity RNA genome into a negative-polarity RNA strand, which will be the template for new positive-polarity RNA genomes. The NS5B protein is phosphorylated by cellular kinases, including Akt. In this work, we have identified several amino acids of NS5B that are phosphorylated by Akt, with positions S27, T53, T267, and S282 giving the most robust results. Site-directed mutagenesis of these residues to mimic (Glu mutants) or prevent (Ala mutants) their phosphorylation resulted in a reduced NS5B in vitro RNA polymerase activity, except for the T267E mutant, the only non-conserved position of all those that are phosphorylated. In addition, in vitro transcribed RNAs derived from HCV complete infectious clones carrying mutations T53E/A and S282E/A were transfected in Huh-7.5 permissive cells, and supernatant viral titers were measured at 6 and 15 days post-transfection. No virus was rescued from the mutants except for T53A at 15 days post-transfection whose viral titer was statistically lower as compared to the wild type. Therefore, phosphorylation of NS5B by cellular kinases is a mechanism of viral polymerase inactivation. Whether this inactivation is a consequence of interaction with cellular kinases or a way to generate inactive NS5B that may have other functions are questions that need further experimental work.
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Affiliation(s)
- Rosario Sabariegos
- Centro Regional de Investigaciones Biomédicas, Universidad de Castilla-La Mancha, Albacete, Spain.,Facultad de Medicina, Universidad de Castilla-La Mancha, Albacete, Spain.,Unidad de Biomedicina UCLM-CSIC, Madrid, Spain
| | - Laura Albentosa-González
- Centro Regional de Investigaciones Biomédicas, Universidad de Castilla-La Mancha, Albacete, Spain
| | - Blanca Palmero
- Centro Regional de Investigaciones Biomédicas, Universidad de Castilla-La Mancha, Albacete, Spain
| | - Pilar Clemente-Casares
- Centro Regional de Investigaciones Biomédicas, Universidad de Castilla-La Mancha, Albacete, Spain.,Unidad de Biomedicina UCLM-CSIC, Madrid, Spain.,Facultad de Farmacia, Universidad de Castilla-La Mancha, Albacete, Spain
| | - Eugenio Ramírez
- Centro Regional de Investigaciones Biomédicas, Universidad de Castilla-La Mancha, Albacete, Spain
| | - Carlos García-Crespo
- Centro de Biología Molecular "Severo Ochoa" (CBMSO) (CSIC-UAM), Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd) del Instituto de Salud Carlos III, Madrid, Spain
| | - Isabel Gallego
- Centro de Biología Molecular "Severo Ochoa" (CBMSO) (CSIC-UAM), Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd) del Instituto de Salud Carlos III, Madrid, Spain
| | - Ana Isabel de Ávila
- Centro de Biología Molecular "Severo Ochoa" (CBMSO) (CSIC-UAM), Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd) del Instituto de Salud Carlos III, Madrid, Spain
| | - Celia Perales
- Centro de Biología Molecular "Severo Ochoa" (CBMSO) (CSIC-UAM), Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd) del Instituto de Salud Carlos III, Madrid, Spain.,Department of Clinical Microbiology, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain
| | - Esteban Domingo
- Unidad de Biomedicina UCLM-CSIC, Madrid, Spain.,Centro de Biología Molecular "Severo Ochoa" (CBMSO) (CSIC-UAM), Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd) del Instituto de Salud Carlos III, Madrid, Spain
| | - Antonio Mas
- Centro Regional de Investigaciones Biomédicas, Universidad de Castilla-La Mancha, Albacete, Spain.,Unidad de Biomedicina UCLM-CSIC, Madrid, Spain.,Facultad de Farmacia, Universidad de Castilla-La Mancha, Albacete, Spain
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Suda G, Sakamoto N. Recent advances in the treatment of hepatitis C virus infection for special populations and remaining problems. J Gastroenterol Hepatol 2021; 36:1152-1158. [PMID: 32667068 DOI: 10.1111/jgh.15189] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 07/02/2020] [Accepted: 07/12/2020] [Indexed: 12/16/2022]
Abstract
Hepatitis C virus (HCV) infection is one of the primary causes of liver cirrhosis, hepatocellular carcinoma (HCC), and liver transplantation (LT). The rate of HCV infection is high in patients on hemodialysis and in patients infected with human immunodeficiency virus (HIV). In liver transplant patients with HCV infection, recurrent HCV infection of the transplanted liver is universal and results in rapid liver fibrosis progression. In patients with HCV/HIV coinfection as well, liver fibrosis advances rapidly. Thus, there is an urgent need for prompt HCV infection treatment in these special populations (i.e. HIV/HCV coinfection, HCV infection after LT, and dialysis patients). Interferon (IFN)-based therapy for HCV infection could not achieve a high rate of sustained viral response and could cause severe adverse events in the aforementioned special populations. Direct-acting antivirals (DAAs) have recently been developed, and clinical trials have shown that IFN-free DAA-based therapies are associated with a significantly better safety and therapeutic profile than IFN-based therapies. However, the majority of the initial DAA trials excluded special populations; thus, the efficacy and safety of IFN-free DAA-based therapy in special populations remained to be clearly established. Although recent clinical trials and clinical studies have shown the high efficacy and safety of this therapy even in special populations, several unresolved problems, including emergence of resistance-associated variants after failure to respond to DAAs and HCC occurrence after DAA therapy, still exist. Hence, in this review, we discuss the recent advances in anti-HCV therapy for special populations and the remaining problems regarding this therapy.
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Affiliation(s)
- Goki Suda
- Department of Gastroenterology and Hepatology, Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Naoya Sakamoto
- Department of Gastroenterology and Hepatology, Graduate School of Medicine, Hokkaido University, Sapporo, Japan
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Suzuki K, Suda G, Yamamoto Y, Furuya K, Baba M, Nakamura A, Miyoshi H, Kimura M, Maehara O, Yamada R, Kitagataya T, Yamamoto K, Shigesawa T, Nakamura A, Ohara M, Kawagishi N, Nakai M, Sho T, Natsuizaka M, Morikawa K, Ogawa K, Ohnishi S, Sakamoto N. Tenofovir-disoproxil-fumarate modulates lipid metabolism via hepatic CD36/PPAR-alpha activation in hepatitis B virus infection. J Gastroenterol 2021; 56:168-180. [PMID: 33211179 DOI: 10.1007/s00535-020-01750-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 11/02/2020] [Indexed: 02/04/2023]
Abstract
BACKGROUND Entecavir and tenofovir-disoproxil-fumarate are first-line nucleos(t)ide analogs (NA) for treatment of hepatitis B virus (HBV) infections; however, their long-term administration can impact extrahepatic organs. Herein, we sought to examine the effect of NA on lipid metabolism while also characterizing the associated mechanism. METHODS A retrospective study was performed on HBV patients administered entecavir or tenofovir-disoproxil-fumarate. Patient clinical information, as well as their preserved serum samples obtained at baseline and 6-12 months after treatment initiation, were analyzed. A 1:1 propensity score matching was applied to the assignment of tenofovir-disoproxil-fumarate or entecavir treatment. Changes in serum cholesterol, including oxidized-LDL, were analyzed. Subsequently, in vitro analysis elucidated the mechanism associated with the effect of NAs on lipid metabolism. RESULTS Administration of tenofovir-disoproxil-fumarate, not entecavir, to chronic HBV patients, decreased serum cholesterol levels, including non-HDL and oxidized-LDL, which are strongly associated with arteriosclerosis. In vitro analysis revealed that tenofovir-disoproxil-fumarate reduced supernatant cholesterol, and upregulated the scavenger receptor, CD36, in hepatocytes. Meanwhile, silencing of hepatic CD36 increased supernatant cholesterol and negated the cholesterol-reducing effect of tenofovir-disoproxil-fumarate in HepG2-cells. Reporter, microarray, and RT-PCR analyses further revealed that tenofovir-disoproxil-fumarate treatment activates PPAR-α-mediated signaling, and upregulates PPAR-α target genes, including CPT1 and CD36. Alternatively, silencing of PPAR-α reversed the effects of tenofovir-disoproxil-fumarate on CD36. CONCLUSIONS Tenofovir-disoproxil-fumarate modulates lipid metabolism by upregulating hepatic CD36 via PPAR-α activation. Since dyslipidemia could be associated with arteriosclerosis and hepatocarcinogenesis, these discoveries provide novel insights into anti-HBV therapies, as well as the associated extrahepatic effects of NA.
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Affiliation(s)
- Kazuharu Suzuki
- Department of Gastroenterology and Hepatology, Graduate School of Medicine, Hokkaido University, North 15, West 7, Kita-ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Goki Suda
- Department of Gastroenterology and Hepatology, Graduate School of Medicine, Hokkaido University, North 15, West 7, Kita-ku, Sapporo, Hokkaido, 060-8638, Japan.
| | - Yoshiya Yamamoto
- Department of Gastroenterology, Hakodate Municipal Hospital, Hokkaido, Japan
| | - Ken Furuya
- Department of Gastroenterology, JCHO Hokkaido Hospital, Hokkaido, Japan
| | - Masaru Baba
- Department of Gastroenterology, JCHO Hokkaido Hospital, Hokkaido, Japan
| | - Akinobu Nakamura
- Department of Rheumatology, Endocrinology and Nephrology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University Graduate School of Medicine, Hokkaido, Japan
| | - Hideaki Miyoshi
- Division of Diabetes and Obesity, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Megumi Kimura
- Department of Gastroenterology and Hepatology, Graduate School of Medicine, Hokkaido University, North 15, West 7, Kita-ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Osamu Maehara
- Department of Gastroenterology, Hakodate Municipal Hospital, Hokkaido, Japan
| | - Ren Yamada
- Department of Gastroenterology and Hepatology, Graduate School of Medicine, Hokkaido University, North 15, West 7, Kita-ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Takashi Kitagataya
- Department of Gastroenterology and Hepatology, Graduate School of Medicine, Hokkaido University, North 15, West 7, Kita-ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Koji Yamamoto
- Department of Gastroenterology and Hepatology, Graduate School of Medicine, Hokkaido University, North 15, West 7, Kita-ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Taku Shigesawa
- Department of Gastroenterology and Hepatology, Graduate School of Medicine, Hokkaido University, North 15, West 7, Kita-ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Akihisa Nakamura
- Department of Gastroenterology and Hepatology, Graduate School of Medicine, Hokkaido University, North 15, West 7, Kita-ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Masatsugu Ohara
- Department of Gastroenterology and Hepatology, Graduate School of Medicine, Hokkaido University, North 15, West 7, Kita-ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Naoki Kawagishi
- Department of Gastroenterology and Hepatology, Graduate School of Medicine, Hokkaido University, North 15, West 7, Kita-ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Masato Nakai
- Department of Gastroenterology and Hepatology, Graduate School of Medicine, Hokkaido University, North 15, West 7, Kita-ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Takuya Sho
- Department of Gastroenterology and Hepatology, Graduate School of Medicine, Hokkaido University, North 15, West 7, Kita-ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Mitsuteru Natsuizaka
- Department of Gastroenterology and Hepatology, Graduate School of Medicine, Hokkaido University, North 15, West 7, Kita-ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Kenichi Morikawa
- Department of Gastroenterology and Hepatology, Graduate School of Medicine, Hokkaido University, North 15, West 7, Kita-ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Koji Ogawa
- Department of Gastroenterology and Hepatology, Graduate School of Medicine, Hokkaido University, North 15, West 7, Kita-ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Shunsuke Ohnishi
- Department of Gastroenterology and Hepatology, Graduate School of Medicine, Hokkaido University, North 15, West 7, Kita-ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Naoya Sakamoto
- Department of Gastroenterology and Hepatology, Graduate School of Medicine, Hokkaido University, North 15, West 7, Kita-ku, Sapporo, Hokkaido, 060-8638, Japan
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Mutations Identified in the Hepatitis C Virus (HCV) Polymerase of Patients with Chronic HCV Treated with Ribavirin Cause Resistance and Affect Viral Replication Fidelity. Antimicrob Agents Chemother 2020; 64:AAC.01417-20. [PMID: 32928732 DOI: 10.1128/aac.01417-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2020] [Accepted: 09/07/2020] [Indexed: 12/11/2022] Open
Abstract
Ribavirin has been used for 25 years to treat patients with chronic hepatitis C virus (HCV) infection; however, its antiviral mechanism of action remains unclear. Here, we studied virus evolution in a subset of samples from a randomized 24-week trial of ribavirin monotherapy versus placebo in chronic HCV patients, as well as the viral resistance mechanisms of the observed ribavirin-associated mutations in cell culture. Thus, we performed next-generation sequencing of the full-length coding sequences of HCV recovered from patients at weeks 0, 12, 20, 32 and 40 and analyzed novel single nucleotide polymorphisms (SNPs), diversity, and mutation-linkage. At week 20, increased genetic diversity was observed in 5 ribavirin-treated compared to 4 placebo-treated HCV patients due to new synonymous SNPs, particularly G-to-A and C-to-U ribavirin-associated transitions. Moreover, emergence of 14 nonsynonymous SNPs in HCV nonstructural 5B (NS5B) occurred in treated patients, but not in placebo controls. Most substitutions located close to the NS5B polymerase nucleotide entry site. Linkage analysis showed that putative resistance mutations were found in the majority of genomes in ribavirin-treated patients. Identified NS5B mutations from genotype 3a patients were further introduced into the genotype 3a cell-culture-adapted DBN strain for studies in Huh7.5 cells. Specific NS5B substitutions, including DBN-D148N+I363V, DBN-A150V+I363V, and DBN-T227S+S183P, conferred resistance to ribavirin in long-term cell culture treatment, possibly by reducing the HCV polymerase error rate. In conclusion, prolonged exposure of HCV to ribavirin in chronic hepatitis C patients induces NS5B resistance mutations leading to increased polymerase fidelity, which could be one mechanism for ribavirin resistance.
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Ward JC, Bowyer S, Chen S, Fernandes Campos GR, Ramirez S, Bukh J, Harris M. Insights into the unique characteristics of hepatitis C virus genotype 3 revealed by development of a robust sub-genomic DBN3a replicon. J Gen Virol 2020; 101:1182-1190. [PMID: 32897181 PMCID: PMC7879556 DOI: 10.1099/jgv.0.001486] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 08/03/2020] [Indexed: 12/14/2022] Open
Abstract
Hepatitis C virus (HCV) is an important human pathogen causing 400 000 chronic liver disease-related deaths annually. Until recently, the majority of laboratory-based investigations into the biology of HCV have focused on the genotype 2 isolate, JFH-1, involving replicons and infectious cell culture systems. However, genotype 2 is one of eight major genotypes of HCV and there is great sequence variation among these genotypes (>30 % nucleotide divergence). In this regard, genotype 3 is the second most common genotype and accounts for 30 % of global HCV cases. Further, genotype 3 is associated with both high levels of inherent resistance to direct-acting antiviral (DAA) therapy, and a more rapid progression to chronic liver diseases. Neither of these two attributes are fully understood, thus robust genotype 3 culture systems to unravel viral replication are required. Here we describe the generation of robust genotype 3 sub-genomic replicons (SGRs) based on the adapted HCV NS3-NS5B replicase from the DBN3a cell culture infectious clone. Such infectious cell culture-adaptive mutations could potentially promote the development of robust SGRs for other HCV strains and genotypes. The novel genotype 3 SGRs have been used both transiently and to establish stable SGR-harbouring cell lines. We show that these resources can be used to investigate aspects of genotype 3 biology, including NS5A function and DAA resistance. They will be useful tools for these studies, circumventing the need to work under the biosafety level 3 (BSL3) containment required in many countries.
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Affiliation(s)
- Joseph C. Ward
- School of Molecular and Cellular Biology, Faculty of Biological Sciences and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK
| | - Sebastian Bowyer
- School of Molecular and Cellular Biology, Faculty of Biological Sciences and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK
| | - Shucheng Chen
- School of Molecular and Cellular Biology, Faculty of Biological Sciences and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK
| | - Guilherme Rodrigues Fernandes Campos
- School of Molecular and Cellular Biology, Faculty of Biological Sciences and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK
- Present address: São Paulo State University, Institute of Biosciences, Languages and Exact Sciences, Cristóvão Colombo Street, 2265, Post Code 15054-000, São José do Rio Preto, São Paulo State, Brazil
| | - Santseharay Ramirez
- Copenhagen Hepatitis C Program (CO-HEP), Department of Infectious Diseases, Hvidovre Hospital, Kettegård Allé 30, DK-2650 Hvidovre, Denmark
- Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark
| | - Jens Bukh
- Copenhagen Hepatitis C Program (CO-HEP), Department of Infectious Diseases, Hvidovre Hospital, Kettegård Allé 30, DK-2650 Hvidovre, Denmark
- Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark
| | - Mark Harris
- School of Molecular and Cellular Biology, Faculty of Biological Sciences and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK
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Hepatitis C virus enhances Rubicon expression, leading to autophagy inhibition and intracellular innate immune activation. Sci Rep 2020; 10:15290. [PMID: 32943718 PMCID: PMC7498609 DOI: 10.1038/s41598-020-72294-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 08/18/2020] [Indexed: 12/19/2022] Open
Abstract
Autophagy, a degradation system, works to maintain cellular homeostasis. However, as the impact of Hepatitis C virus (HCV) infection on hepatocyte autophagy and its effect on HCV replication remain unclear, we examined them. HCV infection suppressed late-stage autophagy and increased Rubicon. siRNA-mediated knockdown of Rubicon promoted autophagy in HCV-infected cells. In Huh-7 cells harbouring the HCV replicon, Rubicon knockdown downregulated the expression of type 1 interferon (IFN)-related genes and upregulated HCV replication. Rubicon overexpression or administration of bafilomycin A1 or chloroquine, an inhibitor of late-stage autophagy, suppressed autophagy and activated the type 1 IFN pathway. On the other hand, Atg7 knockout suppressed early-stage autophagy and did not activate the type 1 IFN pathway. In livers of humanized liver chimeric mice, HCV infection increased Rubicon and enhanced type 1 IFN signalling. Elimination of HCV in the mice reduced the increase in Rubicon due to HCV infection. The expression levels of Rubicon and IFN-stimulated genes in chronic hepatitis C patients were higher than those in non-B, non-C hepatitis patients. HCV infection increased Rubicon and suppressed hepatocyte autophagy, leading to activation of the intracellular immune response. Rubicon induction is involved in HCV replication via activation of the intracellular immune response.
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Mejer N, Galli A, Ramirez S, Fahnøe U, Benfield T, Bukh J. Ribavirin inhibition of cell-culture infectious hepatitis C genotype 1-3 viruses is strain-dependent. Virology 2019; 540:132-140. [PMID: 31778898 DOI: 10.1016/j.virol.2019.09.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 09/27/2019] [Accepted: 09/27/2019] [Indexed: 12/20/2022]
Abstract
Ribavirin remains relevant for successful treatment of chronic hepatitis C virus (HCV) infections in low-income settings, as well as for therapy of difficult-to-treat HCV patients. We studied the effect of ribavirin against cell-culture adapted HCV of genotypes 1, 2 and 3, representing ~80% of global infections. TNcc(1a) was the most sensitive to ribavirin, while J6/JFH1(2a) was the most resistant. EC50s ranged from 21 μM (95%CI: 20-22 μM) to 189 μM (95%CI: 173-207 μM). Substitutions at position 415 of NS5B resulted in little or no change to ribavirin sensitivity (0.7-0.9 fold) but conferred moderate drug resistance during extended treatment of genotype 1 (1.8-fold). NS5A and NS5B sequences could alter ribavirin sensitivity 2-4-fold, although their contribution was not simply additive. Finally, we detected limited accumulation of mutations associated with ribavirin treatment. Our findings show that the antiviral effect of ribavirin on HCV is strain-dependent and is influenced by the specific sequence of multiple HCV nonstructural proteins.
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Affiliation(s)
- Niels Mejer
- Copenhagen Hepatitis C Program (CO-HEP), Department of Infectious Diseases, Hvidovre Hospital and Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Department of Infectious Diseases, Hvidovre Hospital, Hvidovre, Denmark
| | - Andrea Galli
- Copenhagen Hepatitis C Program (CO-HEP), Department of Infectious Diseases, Hvidovre Hospital and Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Department of Infectious Diseases, Hvidovre Hospital, Hvidovre, Denmark
| | - Santseharay Ramirez
- Copenhagen Hepatitis C Program (CO-HEP), Department of Infectious Diseases, Hvidovre Hospital and Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Department of Infectious Diseases, Hvidovre Hospital, Hvidovre, Denmark
| | - Ulrik Fahnøe
- Copenhagen Hepatitis C Program (CO-HEP), Department of Infectious Diseases, Hvidovre Hospital and Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Department of Infectious Diseases, Hvidovre Hospital, Hvidovre, Denmark
| | - Thomas Benfield
- Department of Infectious Diseases, Hvidovre Hospital, Hvidovre, Denmark; Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
| | - Jens Bukh
- Copenhagen Hepatitis C Program (CO-HEP), Department of Infectious Diseases, Hvidovre Hospital and Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Department of Infectious Diseases, Hvidovre Hospital, Hvidovre, Denmark.
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