scholarly journals The Host Factor Erlin-1 is Required for Efficient Hepatitis C Virus Infection

Cells ◽  
2019 ◽  
Vol 8 (12) ◽  
pp. 1555 ◽  
Author(s):  
Christina Whitten-Bauer ◽  
Josan Chung ◽  
Andoni Gómez-Moreno ◽  
Pilar Gomollón-Zueco ◽  
Michael D. Huber ◽  
...  
Keyword(s):  
Life Cycle ◽  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Protein Expression ◽  
Virus Production ◽  
Degradation Pathway ◽  
Hcv Infection ◽  
Cholesterol Homeostasis ◽  
Cellular Factor ◽  
Cellular Factors

Development of hepatitis C virus (HCV) infection cell culture systems has permitted the identification of cellular factors that regulate the HCV life cycle. Some of these cellular factors affect steps in the viral life cycle that are tightly associated with intracellular membranes derived from the endoplasmic reticulum (ER). Here, we describe the discovery of erlin-1 protein as a cellular factor that regulates HCV infection. Erlin-1 is a cholesterol-binding protein located in detergent-resistant membranes within the ER. It is implicated in cholesterol homeostasis and the ER-associated degradation pathway. Silencing of erlin-1 protein expression by siRNA led to decreased infection efficiency characterized by reduction in intracellular RNA accumulation, HCV protein expression and virus production. Mechanistic studies revealed that erlin-1 protein is required early in the infection, downstream of cell entry and primary translation, specifically to initiate RNA replication, and later in the infection to support infectious virus production. This study identifies erlin-1 protein as an important cellular factor regulating HCV infection.

scholarly journals Hepatitis C Virus p7 and NS2 Proteins Are Essential for Production of Infectious Virus

2007 ◽  
Vol 81 (16) ◽  
pp. 8374-8383 ◽  
Author(s):  
Christopher T. Jones ◽  
Catherine L. Murray ◽  
Dawnnica K. Eastman ◽  
Jodie Tassello ◽  
Charles M. Rice
Keyword(s):  
Life Cycle ◽  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Infectious Virus ◽  
Early Stage ◽  
Virus Production ◽  
Health Concern ◽  
Cell Culture Systems ◽  
Catalytic Active Site

ABSTRACT Hepatitis C virus (HCV) infection is a global health concern affecting an estimated 3% of the world's population. Recently, cell culture systems have been established, allowing recapitulation of the complete virus life cycle for the first time. Since the HCV proteins p7 and NS2 are not predicted to be major components of the virion, nor are they required for RNA replication, we investigated whether they might have other roles in the viral life cycle. Here we utilize the recently described infectious J6/JFH chimera to establish that the p7 and NS2 proteins are essential for HCV infectivity. Furthermore, unprocessed forms of p7 and NS2 were not required for this activity. Mutation of two conserved basic residues, previously shown to be important for the ion channel activity of p7 in vitro, drastically impaired infectious virus production. The protease domain of NS2 was required for infectivity, whereas its catalytic active site was dispensable. We conclude that p7 and NS2 function at an early stage of virion morphogenesis, prior to the assembly of infectious virus.

Amiodarone inhibits the entry and assembly steps of hepatitis C virus life cycle

2013 ◽  
Vol 125 (9) ◽  
pp. 439-448 ◽  
Author(s):  
Yuan-Lung Cheng ◽  
Keng-Hsueh Lan ◽  
Wei-Ping Lee ◽  
Szu-Han Tseng ◽  
Li-Rong Hung ◽  
...  
Keyword(s):  
Life Cycle ◽  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Inhibitory Effect ◽  
Hcv Infection ◽  
Receptor Expression ◽  
Current Standard ◽  
Protein Activity ◽  
Entry Site

HCV (hepatitis C virus) infection affects an estimated 180 million people in the world's population. Adverse effects occur frequently with current standard treatment of interferon and ribavirin, while resistance of new direct anti-viral agents, NS3 protease inhibitors, is a major concern because of their single anti-HCV mechanism against the viral factor. New anti-viral agents are needed to resolve the problems. Amiodarone, an anti-arrhythmic drug, has recently been shown to inhibit HCV infection in vitro. The detailed mechanism has yet to be clarified. The aim of the present study was to elucidate the molecular mechanism of the inhibitory effect of amiodarone on HCV life cycle. The effect of amiodarone on HCV life cycle was investigated in Huh-7.5.1 cells with HCVcc (cell culture-derived HCV), HCVpp (HCV pseudoviral particles), sub-genomic replicons, IRES (internal ribosomal entry site)-mediated translation assay, and intracellular and extracellular infectivity assays. The administration of amiodarone appeared to inhibit HCV entry independent of genotypes, which was attributed to the down-regulation of CD81 receptor expression. The inhibitory effect of amiodarone also manifested in the HCV assembly step, via the suppression of MTP (microsomal triacylglycerol transfer protein) activity. Amiodarone revealed no effects on HCV replication and translation. With the host factor-targeting characteristics, amiodarone may be an attractive agent for the treatment of HCV infection.

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.

scholarly journals A Conserved Proline between Domains II and III of Hepatitis C Virus NS5A Influences both RNA Replication and Virus Assembly

2009 ◽  
Vol 83 (20) ◽  
pp. 10788-10796 ◽  
Author(s):  
Mair Hughes ◽  
Sarah Gretton ◽  
Holly Shelton ◽  
David D. Brown ◽  
Christopher J. McCormick ◽  
...  
Keyword(s):  
Life Cycle ◽  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Virus Assembly ◽  
Infectious Clone ◽  
Consensus Sequence ◽  
Virus Production ◽  
Rna Replication ◽  
Subgenomic Replicon ◽  
Genotype 1B

ABSTRACT We previously demonstrated that two closely spaced polyproline motifs, with the consensus sequence Pro-X-X-Pro-X-Lys/Arg, located between residues 343 to 356 of NS5A, mediated interactions with cellular SH3 domains. The N-terminal motif (termed PP2.1) is only conserved in genotype 1 isolates, whereas the C-terminal motif (PP2.2) is conserved throughout all hepatitis C virus (HCV) isolates, although this motif was shown to be dispensable for replication of the genotype 1b subgenomic replicon. In order to investigate the potential role of these motifs in the viral life cycle, we have undertaken a detailed mutagenic analysis of these proline residues in the context of both genotype 1b (FK5.1) or 2a subgenomic replicons and the genotype 2a infectious clone, JFH-1. We show that the PP2.2 motif is dispensable for RNA replication of all subgenomic replicons and, furthermore, is not required for virus production in JFH-1. In contrast, the PP2.1 motif is only required for genotype 1b RNA replication. Mutation of proline 346 within PP2.1 to alanine dramatically attenuated genotype 1b replicon replication in three distinct genetic backgrounds, but the corresponding proline 342 was not required for replication of the JFH-1 subgenomic replicon. However, the P342A mutation resulted in both a delay to virus release and a modest (up to 10-fold) reduction in virus production. These data point to critical roles for these proline residues at multiple stages in the HCV life cycle; however, they also caution against extrapolation of data from culture-adapted replicons to infectious virus.

scholarly journals Hepatitis C Virus Infection Alters P-Body Composition but Is Independent of P-Body Granules

2012 ◽  
Vol 86 (16) ◽  
pp. 8740-8749 ◽  
Author(s):  
Gemma Pérez-Vilaró ◽  
Nicoletta Scheller ◽  
Verónica Saludes ◽  
Juana Díez
Keyword(s):  
Body Composition ◽  
Life Cycle ◽  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Hcv Infection ◽  
Hcv Rna ◽  
Subgenomic Replicon ◽  
Altered Expression ◽  
P Bodies ◽  
Body Components

Processing bodies (P-bodies) are highly dynamic cytoplasmic granules conserved among eukaryotes. They are present under normal growth conditions and contain translationally repressed mRNAs together with proteins from the mRNA decay and microRNA (miRNA) machineries. We have previously shown that the core P-body components PatL1, LSm1, and DDX6 (Rck/p54) are required for hepatitis C virus (HCV) RNA replication; however, how HCV infection affects P-body granules and whether P-body granulesper seinfluence the HCV life cycle remain unresolved issues. Here we show that HCV infection alters P-body composition by specifically changing the localization pattern of P-body components that are required for HCV replication. This effect was not related to an altered expression level of these components and could be reversed by inhibiting HCV replication with a polymerase inhibitor. Similar observations were obtained with a subgenomic replicon that supports only HCV translation and replication, indicating that these early steps of the HCV life cycle trigger the P-body alterations. Finally, P-body disruption by Rap55 depletion did not affect viral titers or HCV protein levels, demonstrating that the localization of PatL1, LSm1, and DDX6 in P-bodies is not required for their function on HCV. Thus, the HCV-induced changes on P-bodies are mechanistically linked to the function of specific P-body components in HCV RNA translation and replication; however, the formation of P-body granules is not required for HCV infection.

scholarly journals Functional Analysis of Hepatitis C Virus (HCV) Envelope Protein E1 Using a trans-Complementation System Reveals a Dual Role of a Putative Fusion Peptide of E1 in both HCV Entry and Morphogenesis

2017 ◽  
Vol 91 (7) ◽  
Author(s):  
Yimin Tong ◽  
Xiaojing Chi ◽  
Wei Yang ◽  
Jin Zhong
Keyword(s):  
Cell Culture ◽  
Life Cycle ◽  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Ectopic Expression ◽  
Fusion Peptide ◽  
Hcv Infection ◽  
Cell Culture Model ◽  
Culture Model

ABSTRACT Hepatitis C virus (HCV) is an enveloped RNA virus belonging to the Flaviviridae family. It infects mainly human hepatocytes and causes chronic liver diseases, including cirrhosis and cancer. HCV encodes two envelope proteins, E1 and E2, that form a heterodimer and mediate virus entry. While E2 has been extensively studied, less has been done so for E1, and its role in the HCV life cycle still needs to be elucidated. Here we developed a new cell culture model for HCV infection based on the trans-complementation of E1. Virus production of the HCV genome lacking the E1-encoding sequence can be efficiently rescued by the ectopic expression of E1 in trans. The resulting virus, designated HCVΔE1, can propagate in packaging cells expressing E1 but results in only single-cycle infection in naive cells. By using the HCVΔE1 system, we explored the role of a putative fusion peptide (FP) of E1 in HCV infection. Interestingly, we found that the FP not only contributes to HCV entry, as previously reported, but also may be involved in virus morphogenesis. Finally, we identified amino acid residues in FP that are critical for biological functions of E1. In summary, our work not only provides a new cell culture model for studying HCV but also provides some insights into understanding the role of E1 in the HCV life cycle. IMPORTANCE Hepatitis C virus (HCV), an enveloped RNA virus, encodes two envelope proteins, E1 and E2, that form a heterodimeric complex to mediate virus entry. Compared to E2, the biological functions of E1 in the virus life cycle are not adequately investigated. Here we developed a new cell culture model for single-cycle HCV infection based on the trans-complementation of E1. The HCV genome lacking the E1-encoding sequence can be efficiently rescued for virus production by the ectopic expression of E1 in trans. This new model renders a unique system to dissect functional domains and motifs in E1. Using this system, we found that a putative fusion peptide in E1 is a multifunctional structural element contributing to both HCV entry and morphogenesis. Our work has provided a new cell culture model to study HCV and provides insights into understanding the biological roles of E1 in the HCV life cycle.

Pharmaceutical Approaches for Treatment of Hepatitis C virus

2020 ◽  
Vol 26 (34) ◽  
pp. 4304-4314 ◽  
Author(s):  
Alireza Milani ◽  
Parya Basimi ◽  
Elnaz Agi ◽  
Azam Bolhassani
Keyword(s):  
Life Cycle ◽  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Drug Interactions ◽  
Clinical Analysis ◽  
Hcv Infection ◽  
Term Therapy ◽  
Duration Of Treatment ◽  
High Genetic Diversity ◽  
Structural And Functional Properties

Many studies have been performed to develop an antiviral therapy against the hepatitis C virus (HCV) infections. The usual treatment for HCV infection is a combination of PEGylated interferon and ribavirin which offer restricted efficiency and major side effects. Thus, recent development in molecular biology of HCV and its life cycle led to the design of many drugs that target viral proteins and host factors required for viral replication. These drugs were named as direct-acting antivirals (DAAs) that were specifically designed for inhibition of viral life cycle, promising tolerability, short duration of treatment, higher barrier to resistance, and fewer drug interactions. The use of DAAs for the treatment of HCV infection resulted in high virological cure rates in patients. However, the use of combined DAA regimens may present drug interactions especially in patients under treatment for other co-morbidities. On the other hand, drug resistance against virus infection determines the success of long-term therapy. High genetic diversity among HCV virions due to error-prone polymerase activity led to the reduced susceptibility to DAA-therapy. Therefore, preclinical and clinical analysis of HCV resistance to novel drugs is needed. In this review, we describe pharmaceutical approaches for HCV treatment, structural and functional properties of DAAs, the principles of HCV drug-drug interaction, and finally HCV resistance to DAAs.

scholarly journals Cellular factors involved in the hepatitis C virus life cycle

2021 ◽  
Vol 27 (28) ◽  
pp. 4555-4581
Author(s):  
Hui-Chun Li ◽  
Chee-Hing Yang ◽  
Shih-Yen Lo
Keyword(s):  
Life Cycle ◽  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Virus Life Cycle ◽  
Cellular Factors

scholarly journals Antiviral Activities of Curcuma Genus against Hepatitis C Virus

2018 ◽  
Vol 13 (12) ◽  
pp. 1934578X1801301 ◽  
Author(s):  
Tutik Sri Wahyuni ◽  
Adita Ayu permatasari ◽  
Tri Widiandani ◽  
Achmad Fuad ◽  
Aty Widyawaruyanti ◽  
...  
Keyword(s):  
Life Cycle ◽  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Mode Of Action ◽  
Biological Activities ◽  
Hcv Infection ◽  
The World ◽  
Action Analysis ◽  
Antiviral Activities ◽  
Post Entry

Hepatitis C virus (HCV) infection is one of the major public health problems in the world. Even though the new agents are shown to increase the sustained virology response, however, there are still many people who cannot access the therapy due to the high cost. Moreover, the emergence of resistance and side effects presented the necessity to develop alternative treatment agents for HCV infection. Plants of the genus of curcuma are popular among traditional medicines in the world, including Indonesia. They have been used for many herb remedies and reported to possess many biological activities. Several plants from the curcuma genus were known as treatment agents in liver disease and jaundice. Our current study determines antiviral activities of Curcuma domestica, Curcuma xanthorrhiza, and Curcuma heyneana against HCV and further examines the mechanism of actions. Antiviral activity was performed by in vitro culture cells using Huh 7.5it cells and treated with the mixture of extract and virus JFH1. The effects of extracts in HCV life cycle were determined by mode of action analysis to examine the action of substances in the entry or post entry steps. The results revealed that ethanol extract of C. domestica, C. xanthorrhiza, and C. heyneana showed strong anti-HCV activities with IC50 values of 1.68 ± 0.05, 4.93 ± 0.42 and 5.49 ± 0.59 μg/mL, respectively without any cytotoxicity effect. Mode of action analysis demonstrated that of C. domestica and C. heyneana exhibit HCV in the entry step, while C. xanthorrhiza inhibit in the entry and post entry steps of HCV life cycle. Docking analysis to predict the interaction of curcumin, the main compound of curcuma genus, revealed a strong interaction between curcumin and 4GAG receptor, a protein involved in the entry step of HCV infection. Moreover, it was also reported to possess good interaction with 4EAW, an HCV NS5B, which plays an important role in HCV replication. These results suggested that C. domestica, C. xanthorrhiza, and C. Heyneana possessed strong inhibition against hepatitis C virus, therefore they may be good candidates for anti-HCV agents.

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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