Interplay between host cell and hepatitis C virus in regulating viral replication

2009 ◽  
Vol 390 (10) ◽  
Author(s):  
Johannes G. Bode ◽  
Erwin D. Brenndörfer ◽  
Juliane Karthe ◽  
Dieter Häussinger
Keyword(s):  
Life Cycle ◽  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Host Cell ◽  
Growth Factor Receptor ◽  
Protein Translation ◽  
Viral Life Cycle ◽  
Cellular Growth ◽  
Viral Genomes ◽  
Associated Proteins

Abstract Viral life cycle as that of the hepatitis C virus (HCV) completely relies on host cell infrastructure, presupposing that the virus has evolved mechanisms to utilize and control all cellular molecules or pathways required for viral life cycle. Hence, HCV must have acquired the ability to gain access to key pathways controlling processes, such as cell growth, apoptosis and protein synthesis, which are all considered to also be crucial for liver regeneration. This occurs in a balanced way permitting persistent replication of viral genomes and production of infectious particles without endangering host cell viability and survival. In particular during the last decade, accumulating evidence indicates that HCV utilizes signaling pathways of the host with major impact on cellular growth, viability, cell cycle or cellular metabolism, such as epidermal growth factor-receptor mediated signals, the PI3K/Akt cascade or the family of Src kinases. Furthermore, HCV specifically interacts with parts of the cellular machinery involved in protein translation, processing, maturation and transport, such as components of the translation complex, the heat shock protein family, the immunophilins or the vesicle-associated membrane protein-associated proteins A and B. The present review focuses on the interplay between viral proteins and these factors of the host cell enabling the virus to utilize host cell infrastructure.

773 HEPATITIS C VIRUS AND LIPID DROPLETS: ROLE OF SEIPIN IN LIPID DROPLET MATURATION AND VIRAL LIFE CYCLE

2011 ◽  
Vol 54 ◽  
pp. S311 ◽  
Author(s):  
S. Clement ◽  
C. Fauvelle ◽  
S. Pascarella ◽  
S. Conzelmann ◽  
V. Kaddai ◽  
...  
Keyword(s):  
Life Cycle ◽  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Lipid Droplet ◽  
Lipid Droplets ◽  
Viral Life Cycle

scholarly journals Role of Conserved E2 Residue W420 in Receptor Binding and Hepatitis C Virus Infection

2016 ◽  
Vol 90 (16) ◽  
pp. 7456-7468 ◽  
Author(s):  
Vanessa M. Cowton ◽  
Allan G. N. Angus ◽  
Sarah J. Cole ◽  
Christina K. Markopoulou ◽  
Ania Owsianka ◽  
...  
Keyword(s):  
Cell Culture ◽  
Life Cycle ◽  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Virus Entry ◽  
Viral Life Cycle ◽  
Tryptophan Residue ◽  
Viral Glycoprotein ◽  
Cd81 Binding

ABSTRACTHepatitis C virus (HCV) enters cells via interactions with several host factors, a key one being that between the viral E2 envelope glycoprotein and the CD81 receptor. We previously identified E2 tryptophan residue 420 (W420) as an essential CD81-binding residue. However, the importance of W420 in the context of the native virion is unknown, as those previous studies predate the infectious HCV cell culture (cell culture-derived HCV [HCVcc]) system. Here, we introduced four separate mutations (F, Y, A, or R) at position 420 within the infectious HCVcc JFH-1 genome and characterized their effects on the viral life cycle. While all mutations reduced E2-CD81 binding, only two (W420A and W420R) reduced HCVcc infectivity. Further analyses of mutants with hydrophobic residues (F or Y) found that interactions with the receptors SR-BI and CD81 were modulated, which in turn determined the viral uptake route. Both mutant viruses were significantly less dependent on SR-BI, and its lipid transfer activity, for virus entry. Furthermore, these viruses were resistant to the drug erlotinib, which targets epidermal growth factor receptor (EGFR) (a host cofactor for HCV entry) and also blocks SR-BI-dependent high-density lipoprotein (HDL)-mediated enhancement of virus entry. Together, our data indicate a model where an alteration at position 420 causes a subtle change in the E2 conformation that prevents interaction with SR-BI and increases accessibility to the CD81-binding site, in turn favoring a particular internalization route. These results further show that a hydrophobic residue with a strong preference for tryptophan at position 420 is important, both functionally and structurally, to provide an additional hydrophobic anchor to stabilize the E2-CD81 interaction.IMPORTANCEHepatitis C virus (HCV) is a leading cause of liver disease, causing up to 500,000 deaths annually. The first step in the viral life cycle is the entry process. This study investigates the role of a highly conserved residue, tryptophan residue 420, of the viral glycoprotein E2 in this process. We analyzed the effect of changing this residue in the virus and confirmed that this region is important for binding to the CD81 receptor. Furthermore, alteration of this residue modulated interactions with the SR-BI receptor, and changes to these key interactions were found to affect the virus internalization route involving the host cofactor EGFR. Our results also show that the nature of the amino acid at this position is important functionally and structurally to provide an anchor point to stabilize the E2-CD81 interaction.

scholarly journals Intracellular Hepatitis C Virus Modeling Predicts Infection Dynamics and Viral Protein Mechanisms

2018 ◽  
Vol 92 (11) ◽  
pp. e02098-17 ◽  
Author(s):  
Thomas R. Aunins ◽  
Katherine A. Marsh ◽  
Gitanjali Subramanya ◽  
Susan L. Uprichard ◽  
Alan S. Perelson ◽  
...  
Keyword(s):  
Life Cycle ◽  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Kinetic Data ◽  
Viral Proteins ◽  
Viral Life Cycle ◽  
Hcv Infection ◽  
Viral Rna ◽  
Model Parameters ◽  
Virus Life Cycle

ABSTRACTHepatitis C virus (HCV) infection is a global health problem, with nearly 2 million new infections occurring every year and up to 85% of these infections becoming chronic infections that pose serious long-term health risks. To effectively reduce the prevalence of HCV infection and associated diseases, it is important to understand the intracellular dynamics of the viral life cycle. Here, we present a detailed mathematical model that represents the full hepatitis C virus life cycle. It is the first full HCV model to be fit to acute intracellular infection data and the first to explore the functions of distinct viral proteins, probing multiple hypotheses ofcis- andtrans-acting mechanisms to provide insights for drug targeting. Model parameters were derived from the literature, experiments, and fitting to experimental intracellular viral RNA, extracellular viral titer, and HCV core and NS3 protein kinetic data from viral inoculation to steady state. Our model predicts higher rates for protein translation and polyprotein cleavage than previous replicon models and demonstrates that the processes of translation and synthesis of viral RNA have the most influence on the levels of the species we tracked in experiments. Overall, our experimental data and the resulting mathematical infection model reveal information about the regulation of core protein during infection, produce specific insights into the roles of the viral core, NS5A, and NS5B proteins, and demonstrate the sensitivities of viral proteins and RNA to distinct reactions within the life cycle.IMPORTANCEWe have designed a model for the full life cycle of hepatitis C virus. Past efforts have largely focused on modeling hepatitis C virus replicon systems, in which transfected subgenomic HCV RNA maintains autonomous replication in the absence of virion production or spread. We started with the general structure of these previous replicon models and expanded it to create a model that incorporates the full virus life cycle as well as additional intracellular mechanistic detail. We compared several different hypotheses that have been proposed for different parts of the life cycle and applied the corresponding model variations to infection data to determine which hypotheses are most consistent with the empirical kinetic data. Because the infection data we have collected for this study are a more physiologically relevant representation of a viral life cycle than data obtained from a replicon system, our model can make more accurate predictions about clinical hepatitis C virus infections.

Host cell kinases and the hepatitis C virus life cycle

2015 ◽  
Vol 1854 (10) ◽  
pp. 1657-1662 ◽  
Author(s):  
Che C. Colpitts ◽  
Joachim Lupberger ◽  
Christian Doerig ◽  
Thomas F. Baumert
Keyword(s):  
Life Cycle ◽  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Host Cell ◽  
Virus Life Cycle

scholarly journals Hepatitis C Virus Genotype 1 to 6 Protease Inhibitor Escape Variants:In VitroSelection, Fitness, and Resistance Patterns in the Context of the Infectious Viral Life Cycle

2016 ◽  
Vol 60 (6) ◽  
pp. 3563-3578 ◽  
Author(s):  
Stéphanie B. N. Serre ◽  
Sanne B. Jensen ◽  
Lubna Ghanem ◽  
Daryl G. Humes ◽  
Santseharay Ramirez ◽  
...  
Keyword(s):  
Life Cycle ◽  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Hot Spots ◽  
Viral Life Cycle ◽  
Viral Fitness ◽  
Cross Resistance ◽  
Genotype 1 ◽  
Genotype 2 ◽  
Ns3 Protease

Hepatitis C virus (HCV) NS3 protease inhibitors (PIs) are important components of novel HCV therapy regimens. Studies of PI resistance initially focused on genotype 1. Therefore, knowledge about the determinants of PI resistance for the highly prevalent genotypes 2 to 6 remains limited. Using Huh7.5 cell culture-infectious HCV recombinants with genotype 1 to 6 NS3 protease, we identified protease positions 54, 155, and 156 as hot spots for the selection of resistance substitutions under treatment with the first licensed PIs, telaprevir and boceprevir. Treatment of a genotype 2 isolate with the newer PIs vaniprevir, faldaprevir, simeprevir, grazoprevir, paritaprevir, and deldeprevir identified positions 156 and 168 as hot spots for resistance; the Y56H substitution emerged for three newer PIs. Substitution selection also depended on the specific recombinant. The substitutions identified conferred cross-resistance to several PIs; however, most substitutions selected under telaprevir or boceprevir treatment conferred less resistance to certain newer PIs. In a single-cycle production assay, across genotypes, PI treatment primarily decreased viral replication, which was rescued by PI resistance substitutions. The substitutions identified resulted in differential effects on viral fitness, depending on the original recombinant and the substitution. Across genotypes, fitness impairment induced by resistance substitutions was due primarily to decreased replication. Most combinations of substitutions that were identified increased resistance or fitness. Combinations of resistance substitutions with fitness-compensating substitutions either rescued replication or compensated for decreased replication by increasing assembly. This comprehensive study provides insight into the selection patterns and effects of PI resistance substitutions for HCV genotypes 1 to 6 in the context of the infectious viral life cycle, which is of interest for clinical and virological HCV research.

scholarly journals Poly(rC)-binding protein 1 limits hepatitis C virus assembly and egress

2021 ◽  
Author(s):  
Sophie E. Cousineau ◽  
Selena M. Sagan
Keyword(s):  
Life Cycle ◽  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Rna Binding ◽  
Binding Protein ◽  
Rna Replication ◽  
Viral Life Cycle ◽  
Viral Rna ◽  
Virion Assembly ◽  
Rna Accumulation

ABSTRACTThe hepatitis C virus (HCV) co-opts a number of cellular elements – including proteins, lipids, and microRNAs – to complete its viral life cycle. The cellular RNA-binding protein poly(rC)-binding protein 1 (PCBP1) had previously been reported to bind the HCV genome 5’ untranslated region (UTR), but its importance in the viral life cycle has remained unclear. Herein, we aimed to clarify the role of PCBP1 in the HCV life cycle. Using the HCV cell culture (HCVcc) system, we found that endogenous PCBP1 knockdown decreased viral RNA accumulation yet increased extracellular virus titers. To dissect PCBP1’s specific role in the viral life cycle, we carried out assays for viral entry, translation, genome stability, RNA replication, virion assembly and egress. We found that PCBP1 did not affect viral entry, translation, RNA stability, or RNA replication in the absence of efficient virion assembly. To specifically examine virion assembly and egress, we inhibited viral RNA replication with an RNA-dependent RNA polymerase inhibitor and tracked both intracellular and extracellular viral titers over time. We found that when viral RNA accumulation was inhibited, knockdown of PCBP1 still resulted in an overall increase in HCV particle secretion. We therefore propose a model where endogenous PCBP1 limits virion assembly and egress, thereby indirectly enhancing viral RNA accumulation in infected cells. This model furthers our understanding of how cellular RNA-binding proteins modulate HCV genomic RNA utilization during the viral life cycle.IMPORTANCEHepatitis C virus (HCV) is a positive-sense RNA virus, and as such, its genome must be a template for multiple mutually exclusive steps of the viral life cycle, namely translation, RNA replication, and virion assembly. However, the mechanism(s) that regulate how the viral genome is used throughout the viral life cycle still remain unclear. A cellular RNA-binding protein – PCBP1 – had previously been reported to bind the HCV genome, but its precise role in the viral life cycle was not known. In this study, we found that depleting PCBP1 decreased viral RNA accumulation but increased virus secretion. We ruled out a role for PCBP1 in virus entry, translation, genome stability or RNA replication, and demonstrate that PCBP1 knockdown enhances virus secretion when RNA replication is inhibited. We conclude that PCBP1 normally prevents virus assembly and egress, which allows more of the viral genomic RNA to be available for translation and viral RNA replication.

scholarly journals Development of a Cell-Based Hepatitis C Virus Infection Fluorescent Resonance Energy Transfer Assay for High-Throughput Antiviral Compound Screening

2009 ◽  
Vol 53 (10) ◽  
pp. 4311-4319 ◽  
Author(s):  
Xuemei Yu ◽  
Bruno Sainz ◽  
Susan L. Uprichard
Keyword(s):  
Cell Culture ◽  
Energy Transfer ◽  
Life Cycle ◽  
Hepatitis C Virus ◽  
Hepatitis C ◽  
High Throughput ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Viral Life Cycle ◽  
Hcv Infection

ABSTRACT A major obstacle in the treatment of chronic hepatitis C virus (HCV) infection has been the lack of effective, well-tolerated therapeutics. Notably, the recent development of the HCV cell culture infection system now allows not only for the study of the entire viral life cycle, but also for the screening of inhibitors against all aspects of HCV infection. However, in order to screen libraries of potential antiviral compounds, it is necessary to develop a highly reproducible, accurate assay for HCV infection adaptable for high-throughput screening (HTS) automation. Using an internally quenched 5-FAM/QXL 520 fluorescence resonance energy transfer (FRET) substrate containing the HCV NS3 peptide cleavage sequence, we report the development of a simple, mix-and-measure, homogenous, cell-based HCV infection assay amendable for HTS. This assay makes use of synchronized, nondividing human hepatoma-derived Huh7 cells, which support more-reproducible long-term HCV infection and can be readily scaled down to a 96-well-plate format. We demonstrate that this stable cell culture method eliminates common problems associated with standard cell-based HTS, such as cell culture variability, poor reproducibility, and low signal intensity. Importantly, this HCV FRET assay not only can identify inhibitors that act throughout the viral life cycle as effectively as more-standard HCV assays, such as real-time quantitative PCR and Western blot analysis, but also exhibits a high degree of accuracy with limited signal variation (i.e., Z′ ≥ 0.6), providing the basis for a robust HTS campaign for screening compound libraries and identifying novel HCV antivirals.

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