Adapted J6/JFH1-based Hepatitis C virus recombinants with genotype-specific NS4A show similar efficacies against lead protease inhibitors, alpha interferon, and a putative NS4A inhibitor.
To facilitate studies of hepatitis C virus (HCV) NS4A, we aimed at developing J6/JFH1-based recombinants with genotype 1- to 7-specific NS4A proteins. We developed efficient culture systems expressing NS4A proteins of genotypes (isolates) 1a (H77 and TN), 1b (J4), 2a (J6), 4a (ED43), 5a (SA13), 6a (HK6a), and 7a (QC69), with peak infectivity titers of ∼3.5 to 4.5 log10 focus-forming units per ml. Except for genotype 2a (J6), growth depended on adaptive mutations identified in long-term culture. Genotype 1a, 1b, and 4a recombinants were adapted by amino acid substitutions F772S (p7) and V1663A (NS4A), while 5a, 6a, and 7a recombinants required additional substitutions in the NS3 protease and/or NS4A. We demonstrated applicability of the developed recombinants for study of antivirals. Genotype 1 to 7 NS4A recombinants showed similar responses to the protease inhibitors telaprevir (VX-950), boceprevir (Sch503034), simeprevir (TMC435350), danoprevir (ITMN-191), and vaniprevir (MK-7009), to alpha interferon 2b, and to the putative NS4A inhibitor ACH-806. The efficacy of ACH-806 was lower than that of protease inhibitors and was not influenced by changes at amino acids 1042 and 1065 (in the NS3 protease), which have been suggested to mediate resistance to ACH-806 in replicons. Genotype 1a, 1b, and 2a recombinants showed viral spread under long-term treatment with ACH-806, without acquisition of resistance mutations in the NS3-NS4A region. Relatively high concentrations of ACH-806 inhibited viral assembly, but not replication, in a single-cycle production assay. The developed HCV culture systems will facilitate studies benefitting from expression of genotype-specific NS4A in a constant backbone in the context of the complete viral replication cycle, including functional studies and evaluations of the efficacy of antivirals.
Copenhagen Hepatitis C Program (CO-HEP), Department of Infectious Diseases and Clinical Research Centre, Copenhagen University Hospital, Hvidovre, and Department of International Health, Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
Judith M
JM
Gottwein
Sanne B
SB
Jensen
Stéphanie B N
SB
Serre
Lubna
L
Ghanem
Troels K H
TK
Scheel
Tanja B
TB
Jensen
Henrik
H
Krarup
Nathalie
N
Uzcategui
Lotte S
LS
Mikkelsen
Jens
J
Bukh
D000998:Antiviral Agents / Q000494:pharmacology; D002352:Carrier Proteins / Q000235:genetics* / Q000378:metabolism; D045744:Cell Line, Tumor; D004305:Dose-Response Relationship, Drug; D024882:Drug Resistance, Viral / Q000235:genetics*; D015870:Gene Expression; D005838:Genotype; D016174:Hepacivirus / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D022781:Hepatocytes / Q000187:drug effects / Q000821:virology; D006801:Humans; D016898:Interferon-alpha / Q000494:pharmacology; D047908:Intracellular Signaling Peptides and Proteins; D010670:Phenylthiourea / Q000031:analogs & derivatives / Q000494:pharmacology; D011480:Protease Inhibitors / Q000494:pharmacology; D016865:Reassortant Viruses / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D011995:Recombination, Genetic; D017361:Viral Nonstructural Proteins / Q000235:genetics* / Q000378:metabolism; D012697:Serine Endopeptidases; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases
D000998:Antiviral Agents; D002352:Carrier Proteins; D016898:Interferon-alpha; D047908:Intracellular Signaling Peptides and Proteins; D010670:Phenylthiourea; D011480:Protease Inhibitors; D017361:Viral Nonstructural Proteins; C530651:1-(4-pentyloxy-3-trifluoromethylphenyl)-3-(pyridine-3-carbonyl)thiourea; C084422:NS3 protein, hepatitis C virus; D012697:Serine Endopeptidases; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases; C455041:NS4A cofactor peptide, Hepatitis C virus