scholarly journals Biochemical Characterization of the Active Anti-Hepatitis C Virus Metabolites of 2,6-Diaminopurine Ribonucleoside Prodrug Compared to Sofosbuvir and BMS-986094

2016 ◽  
Vol 60 (8) ◽  
pp. 4659-4669 ◽  
Author(s):  
Maryam Ehteshami ◽  
Sijia Tao ◽  
Tugba Ozturk ◽  
Longhu Zhou ◽  
Jong Hyun Cho ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Biochemical Characterization ◽  
Nonstructural Protein ◽  
Nucleoside Triphosphate ◽  
Hcv Rna ◽  
Mitochondrial Rna ◽  
Active Metabolites

ABSTRACTRibonucleoside analog inhibitors (rNAI) target the hepatitis C virus (HCV) RNA-dependent RNA polymerase nonstructural protein 5B (NS5B) and cause RNA chain termination. Here, we expand our studies on β-d-2′-C-methyl-2,6-diaminopurine-ribonucleotide (DAPN) phosphoramidate prodrug 1 (PD1) as a novel investigational inhibitor of HCV. DAPN-PD1 is metabolized intracellularly into two distinct bioactive nucleoside triphosphate (TP) analogs. The first metabolite, 2′-C-methyl-GTP, is a well-characterized inhibitor of NS5B polymerase, whereas the second metabolite, 2′-C-methyl-DAPN-TP, behaves as an adenosine base analog.In vitroassays suggest that both metabolites are inhibitors of NS5B-mediated RNA polymerization. Additional factors, such as rNAI-TP incorporation efficiencies, intracellular rNAI-TP levels, and competition with natural ribonucleotides, were examined in order to further characterize the potential role of each nucleotide metabolitein vivo. Finally, we found that although both 2′-C-methyl-GTP and 2′-C-methyl-DAPN-TP were weak substrates for human mitochondrial RNA (mtRNA) polymerase (POLRMT)in vitro, DAPN-PD1 did not cause off-target inhibition of mtRNA transcription in Huh-7 cells. In contrast, administration of BMS-986094, which also generates 2′-C-methyl-GTP and previously has been associated with toxicity in humans, caused detectable inhibition of mtRNA transcription. Metabolism of BMS-986094 in Huh-7 cells leads to 87-fold higher levels of intracellular 2′-C-methyl-GTP than DAPN-PD1. Collectively, our data characterize DAPN-PD1 as a novel and potent antiviral agent that combines the delivery of two active metabolites.

scholarly journals Preclinical Profile and Clinical Efficacy of a Novel Hepatitis C Virus NS5A Inhibitor, EDP-239

2016 ◽  
Vol 60 (10) ◽  
pp. 6207-6215 ◽  
Author(s):  
Christopher M. Owens ◽  
Bradley B. Brasher ◽  
Alex Polemeropoulos ◽  
Michael H. J. Rhodin ◽  
Nicole McAllister ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Nonstructural Protein ◽  
Viral Rna ◽  
Controlled Clinical Trial ◽  
Genotype 1A ◽  
Pharmacokinetic Properties ◽  
Direct Acting

ABSTRACTEDP-239, a novel hepatitis C virus (HCV) inhibitor targeting nonstructural protein 5A (NS5A), has been investigatedin vitroandin vivo. EDP-239 is a potent, selective inhibitor with potency at picomolar to nanomolar concentrations against HCV genotypes 1 through 6. In the presence of human serum, the potency of EDP-239 was reduced by less than 4-fold. EDP-239 is additive to synergistic with other direct-acting antivirals (DAAs) or host-targeted antivirals (HTAs) in blocking HCV replication and suppresses the selection of resistancein vitro. Furthermore, EDP-239 retains potency against known DAA- or HTA-resistant variants, with half-maximal effective concentrations (EC50s) equivalent to those for the wild type. In a phase I, single-ascending-dose, placebo-controlled clinical trial, EDP-239 demonstrated excellent pharmacokinetic properties that supported once daily dosing. A single 100-mg dose of EDP-239 resulted in reductions in HCV genotype 1a viral RNA of >3 log10IU/ml within the first 48 h after dosing and reductions in genotype 1b viral RNA of >4-log10IU/ml within 96 h. (This study has been registered at ClinicalTrials.gov under identifier NCT01856426.)

scholarly journals A role for B cells to transmit hepatitis C virus infection

2020 ◽  
Author(s):  
Isabelle Desombere ◽  
Freya Van Houtte ◽  
Ali Farhoudi ◽  
Lieven Verhoye ◽  
Caroline Buysschaert ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
B Cells ◽  
Neutralizing Antibody ◽  
Hcv Rna ◽  
Serum Samples ◽  
Cell Culture Systems ◽  
Hcv Transmission

Abstract Hepatitis C virus (HCV) is highly variable and transmits through infected blood to establish a chronic liver infection in the majority of patients. Our knowledge of the infectivity of clinical HCV strains is hampered by the lack of in vitro cell culture systems that support efficient viral replication. We previously reported that laboratory strains of HCV associated with non-permissive B cells could trans-infect hepatocytes and thereby evade host neutralizing antibody responses, suggesting a role for B cells in HCV transmission. To evaluate this hypothesis, we assessed the ability of B cells and sera from recent (<2 years) or chronic (≥ 2 years) infections to infect humanized liver chimeric mice. HCV was efficiently transmitted by B cells from chronically infected patients whereas the sera were non-infectious. In contrast, we noted that B cells from recently infected patients failed to transmit HCV to the mice, whereas all serum samples were infectious. Only patients with circulating anti-glycoprotein antibodies harbored genomic HCV-RNA in B cells. Taken together, our studies provide direct in vivo evidence for HCV transmission by B cells and these findings may have clinical implications for prophylactic and therapeutic antibody-based vaccine design.

scholarly journals Effect of Hepatitis C Virus (HCV) NS5B-Nucleolin Interaction on HCV Replication with HCV Subgenomic Replicon

2006 ◽  
Vol 80 (7) ◽  
pp. 3332-3340 ◽  
Author(s):  
Tetsuro Shimakami ◽  
Masao Honda ◽  
Takashi Kusakawa ◽  
Takayuki Murata ◽  
Kunitada Shimotohno ◽  
...  
Keyword(s):  
Amino Acids ◽  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Nonstructural Protein ◽  
Polymerase Activity ◽  
Subgenomic Replicon ◽  
Huh7 Cells ◽  
Hcv Ns5b

ABSTRACT We previously reported that nucleolin, a representative nucleolar marker, interacts with nonstructural protein 5B (NS5B) of hepatitis C virus (HCV) through two independent regions of NS5B, amino acids 208 to 214 and 500 to 506. We also showed that truncated nucleolin that harbors the NS5B-binding region inhibited the RNA-dependent RNA polymerase activity of NS5B in vitro, suggesting that nucleolin may be involved in HCV replication. To address this question, we focused on NS5B amino acids 208 to 214. We constructed one alanine-substituted clustered mutant (CM) replicon, in which all the amino acids in this region were changed to alanine, as well as seven different point mutant (PM) replicons, each of which harbored an alanine substitution at one of the amino acids in the region. After transfection into Huh7 cells, the CM replicon and the PM replicon containing NS5B W208A could not replicate, whereas the remaining PM replicons were able to replicate. In vivo immunoprecipitation also showed that the W208 residue of NS5B was essential for its interaction with nucleolin, strongly suggesting that this interaction is essential for HCV replication. To gain further insight into the role of nucleolin in HCV replication, we utilized the small interfering RNA (siRNA) technique to investigate the knockdown effect of nucleolin on HCV replication. Cotransfection of replicon RNA and nucleolin siRNA into Huh7 cells moderately inhibited HCV replication, although suppression of nucleolin did not affect cell proliferation. Taken together, our findings strongly suggest that nucleolin is a host component that interacts with HCV NS5B and is indispensable for HCV replication.

scholarly journals Preclinical and Clinical Resistance Profile of EDP-239, a Novel Hepatitis C Virus NS5A Inhibitor

2016 ◽  
Vol 60 (10) ◽  
pp. 6216-6226 ◽  
Author(s):  
Christopher M. Owens ◽  
Bradley B. Brasher ◽  
Alex Polemeropoulos ◽  
Michael H. J. Rhodin ◽  
Nicole McAllister ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Amino Acid ◽  
Nonstructural Protein ◽  
Subgenomic Replicon ◽  
Ns5a Inhibitor ◽  
Clinical Resistance ◽  
Ns5a Sequence

ABSTRACTEDP-239, a potent and selective hepatitis C virus (HCV) nonstructural protein 5A (NS5A) inhibitor developed for the treatment of HCV infection, has been investigatedin vitroandin vivo. This study sought to characterize genotypic changes in the HCV NS5A sequence of genotype 1 (GT1) replicons and to compare those changes to GT1 viral RNA mutations isolated from clinical trial patients. Resistance selection experimentsin vitrousing a subgenomic replicon identified resistance-associated mutations (RAMs) at GT1a NS5A amino acid positions 24, 28, 30, 31, and 93 that confer various degrees of resistance to EDP-239. Key RAMs were similarly identified in GT1b NS5A at amino acid positions 31 and 93. Mutations F36L in GT1a and A92V in GT1b do not confer resistance to EDP-239 individually but were found to enhance the resistance of GT1a K24R and GT1b Y93H. RAMs were identified in GT1 patients at baseline or after dosing with EDP-239 that were similar to those detectedin vitro. Baseline RAMs identified at NS5A position 93 in GT1, or positions 28 or 30 in GT1a only, correlated with a reduced treatment response. RAMs at additional positions were also detected and may have contributed to reduced EDP-239 efficacy. The most common GT1a and GT1b RAMs found to persist up to weeks 12, 24, or 48 were those at NS5A positions 28, 30, 31, 58 (GT1a only), and 93. Those RAMs persisting at the highest frequencies up to weeks 24 or 48 were L31M and Q30H/R for GT1a and L31M and Y93H for GT1b. (This study has been registered at ClinicalTrials.gov under identifier NCT01856426.)

scholarly journals Hepatitis C Virus Genotype 5a Subgenomic Replicons for Evaluation of Direct-Acting Antiviral Agents

2014 ◽  
Vol 58 (9) ◽  
pp. 5386-5394 ◽  
Author(s):  
Constance N. Wose Kinge ◽  
Christine Espiritu ◽  
Nishi Prabdial-Sing ◽  
Nomathamsaqa Patricia Sithebe ◽  
Mohsan Saeed ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Nonstructural Protein ◽  
Antiviral Agents ◽  
Rna Replication ◽  
Firefly Luciferase ◽  
Hcv Rna ◽  
Virus Genotype ◽  
Subgenomic Replicon

ABSTRACTHepatitis C virus (HCV) exists as six major genotypes that differ in geographical distribution, pathogenesis, and response to antiviral therapy.In vitroreplication systems for all HCV genotypes except genotype 5 have been reported. In this study, we recovered genotype 5a full-length genomes from four infected voluntary blood donors in South Africa and established a G418-selectable subgenomic replicon system using one of these strains. The replicon derived from the wild-type sequence failed to replicate in Huh-7.5 cells. However, the inclusion of the S2205I amino acid substitution, a cell culture-adaptive change originally described for a genotype 1b replicon, resulted in a small number of G418-resistant cell colonies. HCV RNA replication in these cells was confirmed by quantification of viral RNA and detection of the nonstructural protein NS5A. Sequence analysis of the viral RNAs isolated from multiple independent cell clones revealed the presence of several nonsynonymous mutations, which were localized mainly in the NS3 protein. These mutations, when introduced back into the parental backbone, significantly increased colony formation. To facilitate convenient monitoring of HCV RNA replication levels, the mutant with the highest replication level was further modified to express a fusion protein of firefly luciferase and neomycin phosphotransferase. Using such replicons from genotypes 1a, 1b, 2a, 3a, 4a, and 5a, we compared the effects of various HCV inhibitors on their replication. In conclusion, we have established anin vitroreplication system for HCV genotype 5a, which will be useful for the development of pan-genotype anti-HCV compounds.

scholarly journals Analysis of hepatitis C virus resistance to silibinin in vitro and in vivo points to a novel mechanism involving nonstructural protein 4B

Hepatology ◽  
2013 ◽  
Vol 57 (3) ◽  
pp. 953-963 ◽  
Author(s):  
Katharina Esser-Nobis ◽  
Inés Romero-Brey ◽  
Tom M. Ganten ◽  
Jérôme Gouttenoire ◽  
Christian Harak ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Virus Resistance ◽  
Nonstructural Protein

scholarly journals Production of Infectious Hepatitis C Virus of Various Genotypes in Cell Cultures

2007 ◽  
Vol 81 (9) ◽  
pp. 4405-4411 ◽  
Author(s):  
Takanobu Kato ◽  
Takuya Matsumura ◽  
Theo Heller ◽  
Satoru Saito ◽  
Ronda K. Sapp ◽  
...  
Keyword(s):  
Cell Culture ◽  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Culture Medium ◽  
Expression System ◽  
Core Antigen ◽  
Hcv Rna ◽  
Transfected Cells

ABSTRACT A unique hepatitis C virus (HCV) strain JFH-1 has been shown to replicate efficiently in cell culture with production of infectious HCV. We previously developed a DNA expression system containing HCV cDNA flanked by two self-cleaving ribozymes to generate HCV particles in cell culture. In this study, we produced HCV particles of various genotypes, including 1a (H77), 1b (CG1b), and 2a (J6 and JFH-1), in the HCV-ribozyme system. The constructs also contain the secreted alkaline phosphatase gene to control for transfection efficiency and the effects of culture conditions. After transfection into the Huh7-derived cell line Huh7.5.1, continuous HCV replication and secretion were confirmed by the detection of HCV RNA and core antigen in the culture medium. HCV replication levels of strains H77, CG1b, and J6 were comparable, whereas the JFH-1 strain replicates at a substantially higher level than the other strains. To evaluate the infectivity in vitro, the culture medium of JFH-1-transfected cells was inoculated into naive Huh7.5.1 cells. HCV proteins were detected by immunofluorescence 3 days after inoculation. To evaluate the infectivity in vivo, the culture medium from HCV genotype 1b-transfected cells was inoculated into a chimpanzee and caused a typical course of HCV infection. The HCV 1b propagated in vitro and in vivo had sequences identical to those of the HCV genomic cDNA used for cell culture transfection. The development of culture systems for production of various HCV genotypes provides a valuable tool not only to study the replication and pathogenesis of HCV but also to screen for antivirals.

scholarly journals The NS4A Protein of Hepatitis C Virus Promotes RNA-Coupled ATP Hydrolysis by the NS3 Helicase

2009 ◽  
Vol 83 (7) ◽  
pp. 3268-3275 ◽  
Author(s):  
Rudolf K. F. Beran ◽  
Brett D. Lindenbach ◽  
Anna Marie Pyle
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Serine Protease ◽  
Protease Activity ◽  
Rna Binding ◽  
Nonstructural Protein ◽  
Helicase Activity ◽  
Protease Domain

ABSTRACT Nonstructural protein 3 (NS3) is an essential replicative component of the hepatitis C virus (HCV) and a member of the DExH/D-box family of proteins. The C-terminal region of NS3 (NS3hel) exhibits RNA-stimulated NTPase and helicase activity, while the N-terminal serine protease domain of NS3 enhances RNA binding and unwinding by NS3hel. The nonstructural protein 4A (NS4A) binds to the NS3 protease domain and serves as an obligate cofactor for NS3 serine protease activity. Given its role in stimulating protease activity, we sought to determine whether NS4A also influences the activity of NS3hel. Here we show that NS4A enhances the ability of NS3hel to bind RNA in the presence of ATP, thereby acting as a cofactor for helicase activity. This effect is mediated by amino acids in the C-terminal acidic domain of NS4A. When these residues are mutated, one observes drastic reductions in ATP-coupled RNA binding and duplex unwinding by NS3. These same mutations are lethal in HCV replicons, thereby establishing in vitro and in vivo that NS4A plays an important role in the helicase mechanism of NS3 and its function in replication.

scholarly journals Interaction with a Ubiquitin-Like Protein Enhances the Ubiquitination and Degradation of Hepatitis C Virus RNA-Dependent RNA Polymerase

2003 ◽  
Vol 77 (7) ◽  
pp. 4149-4159 ◽  
Author(s):  
Lu Gao ◽  
Hong Tu ◽  
Stephanie T. Shi ◽  
Ki-Jeong Lee ◽  
Miyuki Asanaka ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Rna Polymerase ◽  
Hcv Rna ◽  
Rna Dependent Rna Polymerase ◽  
Subgenomic Replicon ◽  
C Terminus ◽  
Huh7 Cells

ABSTRACT To identify potential cellular regulators of hepatitis C virus (HCV) RNA-dependent RNA polymerase (NS5B), we searched for cellular proteins interacting with NS5B protein by yeast two-hybrid screening of a human hepatocyte cDNA library. We identified a ubiquitin-like protein, hPLIC1 (for human homolog 1 of protein linking intergrin-associated protein and cytoskeleton), which is expressed in the liver (M. F. Kleijnen, A. H. Shih, P. Zhou, S. Kumar, R. E. Soccio, N. L. Kedersha, G. Gill, and P. M. Howley, Mol. Cell 6: 409-419, 2000). In vitro binding assays and in vivo coimmunoprecipitation studies confirmed the interaction between hPLIC1 and NS5B, which occurred through the ubiquitin-associated domain at the C terminus of the hPLIC1 protein. As hPLICs have been shown to physically associate with two E3 ubiquitin protein ligases as well as proteasomes (Kleijnen et al., Mol. Cell 6: 409-419, 2000), we investigated whether the stability and posttranslational modification of NS5B were affected by hPLIC1. A pulse-chase labeling experiment revealed that overexpression of hPLIC1, but not the mutant lacking the NS5B-binding domain, significantly shortened the half-life of NS5B and enhanced the polyubiquitination of NS5B. Furthermore, in Huh7 cells that express an HCV subgenomic replicon, the amounts of both NS5B and the replicon RNA were reduced by overexpression of hPLIC1. Thus, hPLIC1 may be a regulator of HCV RNA replication through interaction with NS5B.

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