scholarly journals Hepatitis C Virus-Induced Degradation of Cell Death-Inducing DFFA-Like Effector B Leads to Hepatic Lipid Dysregulation

2016 ◽  
Vol 90 (8) ◽  
pp. 4174-4185 ◽  
Author(s):  
Emily M. Lee ◽  
Ali Alsagheir ◽  
Xianfang Wu ◽  
Christy Hammack ◽  
John McLauchlan ◽  
...  
Keyword(s):  
Cell Death ◽  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Hepatic Steatosis ◽  
Hepatoma Cell ◽  
Biological Significance ◽  
Proteolytic Cleavage ◽  
Hcv Infection ◽  
Hepatoma Cell Line ◽  
Liver Protein

ABSTRACTIndividuals chronically infected with hepatitis C virus (HCV) commonly exhibit hepatic intracellular lipid accumulation, termed steatosis. HCV infection perturbs host lipid metabolism through both cellular and virus-induced mechanisms, with the viral core protein playing an important role in steatosis development. We have recently identified a liver protein, the cell death-inducing DFFA-like effector B (CIDEB), as an HCV entry host dependence factor that is downregulated by HCV infection in a cell culture model. In this study, we investigated the biological significance and molecular mechanism of this downregulation. HCV infection in a mouse model downregulated CIDEB in the liver tissue, and knockout of the CIDEB gene in a hepatoma cell line results in multiple aspects of lipid dysregulation that can contribute to hepatic steatosis, including reduced triglyceride secretion, lower lipidation of very-low-density lipoproteins, and increased lipid droplet (LD) stability. The potential link between CIDEB downregulation and steatosis is further supported by the requirement of the HCV core and its LD localization for CIDEB downregulation, which utilize a proteolytic cleavage event that is independent of the cellular proteasomal degradation of CIDEB.IMPORTANCEOur data demonstrate that HCV infection of human hepatocytesin vitroandin vivoresults in CIDEB downregulation via a proteolytic cleavage event. Reduction of CIDEB protein levels by HCV or gene editing, in turn, leads to multiple aspects of lipid dysregulation, including LD stabilization. Consequently, CIDEB downregulation may contribute to HCV-induced hepatic steatosis.

scholarly journals Hepatitis C Virus Induces Proteolytic Cleavage of Sterol Regulatory Element Binding Proteins and Stimulates Their Phosphorylation via Oxidative Stress

2007 ◽  
Vol 81 (15) ◽  
pp. 8122-8130 ◽  
Author(s):  
Gulam Waris ◽  
Daniel Jeffery Felmlee ◽  
Francesco Negro ◽  
Aleem Siddiqui
Keyword(s):  
Oxidative Stress ◽  
Hepatitis C Virus ◽  
Lipid Metabolism ◽  
Hepatitis C ◽  
Hepatic Steatosis ◽  
Binding Proteins ◽  
Regulatory Element ◽  
Proteolytic Cleavage ◽  
Hcv Infection ◽  
Sterol Regulatory Element

ABSTRACT Hepatic steatosis is a common histological feature of chronic hepatitis C. Hepatitis C virus (HCV) gene expression has been shown to alter host cell cholesterol/lipid metabolism and thus induce hepatic steatosis. Since sterol regulatory element binding proteins (SREBPs) are major regulators of lipid metabolism, we sought to determine whether genotype 2a-based HCV infection induces the expression and posttranslational activation of SREBPs. HCV infection stimulates the expression of genes related to lipogenesis. HCV induces the proteolytic cleavage of SREBPs. HCV core and NS4b derived from genotype 3a are also individually capable of inducing the proteolytic processing of SREBPs. Further, we demonstrate that HCV stimulates the phosphorylation of SREBPs. Our studies show that HCV-induced oxidative stress and subsequent activation of the phosphatidylinositol 3-kinase (PI3-K)-Akt pathway and inactivation (phosphorylation) of PTEN (phosphatase and tensin homologue) mediate the transactivation of SREBPs. HCV-induced SREBP-1 and -2 activities were sensitive to antioxidant (pyrrolidine dithiocarbamate), Ca2+ chelator 1,2-bis(aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid-tetra(acetoxymethyl) ester (BAPTA-AM), and PI3-K inhibitor (LY294002). Collectively, these studies provide insight into the mechanisms of hepatic steatosis associated with HCV infection.

scholarly journals Dissecting the Interferon-Induced Inhibition of Hepatitis C Virus Replication by Using a Novel Host Cell Line

2005 ◽  
Vol 79 (21) ◽  
pp. 13778-13793 ◽  
Author(s):  
Marc P. Windisch ◽  
Michael Frese ◽  
Artur Kaul ◽  
Martin Trippler ◽  
Volker Lohmann ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Host Cell ◽  
Cell Line ◽  
Nuclear Translocation ◽  
Hepatoma Cell ◽  
Hepatoma Cell Line ◽  
Adaptive Mutations ◽  
Antiviral Compounds ◽  
Ifn Γ

ABSTRACT The Hepatitis C virus (HCV), a member of the family Flaviviridae, is a major cause of chronic liver disease. Patients are currently treated with alpha interferon (IFN-α) that is given alone or in combination with ribavirin. Unfortunately, this treatment is ineffective in eliminating the virus in a large proportion of individuals. IFN-induced antiviral activities have been intensively studied in the HCV replicon system. It was found that both IFN-α and IFN-γ inhibit HCV replicons, but the underlying mechanisms have not yet been identified. Of note is that nearly all of these studies were performed with the human hepatoma cell line Huh-7. Here, we report that genotypes 1b and 2a replicons also replicate in the human hepatoblastoma cell line HuH6. Similar to what has been described for Huh-7 cells, we observed that efficient HCV replication in HuH6 cells depends on the presence of cell culture-adaptive mutations and the permissiveness of the host cell. However, three major differences exist: in HuH6 cells, viral replication is (i) independent from ongoing cell proliferation, (ii) less sensitive to certain antiviral compounds, and (iii) highly resistant to IFN-γ. The latter is not due to a general defect in IFN signaling, as IFN-γ induces the nuclear translocation of signal transducer and activator of transcription 1 (STAT1), the enhanced transcription of several IFN-regulated genes, and the inhibition of unrelated viruses such as influenza A virus and Semliki Forest virus. Taken together, the results establish HuH6 replicon cells as a valuable tool for IFN studies and for the evaluation of antiviral compounds.

scholarly journals Gene Expression Profiling of Different Huh7 Variants Reveals Novel Hepatitis C Virus Host Factors

Viruses ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 36
Author(s):  
Christopher Dächert ◽  
Evgeny Gladilin ◽  
Marco Binder
Keyword(s):  
Gene Expression ◽  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Gene Expression Profiling ◽  
Cell Line ◽  
Expression Profiling ◽  
Hepatoma Cell ◽  
Host Factors ◽  
Hepatoma Cell Line ◽  
Huh7 Cells

Chronic Hepatitis C virus (HCV) infection still constitutes a major global health problem with almost half a million deaths per year. To date, the human hepatoma cell line Huh7 and its derivatives is the only cell line that robustly replicates HCV. However, even different subclones and passages of this single cell line exhibit tremendous differences in HCV replication efficiency. By comparative gene expression profiling using a multi-pronged correlation analysis across eight different Huh7 variants, we identified 34 candidate host factors possibly affecting HCV permissiveness. For seven of the candidates, we could show by knock-down studies their implication in HCV replication. Notably, for at least four of them, we furthermore found that overexpression boosted HCV replication in lowly permissive Huh7 cells, most prominently for the histone-binding transcriptional repressor THAP7 and the nuclear receptor NR0B2. For NR0B2, our results suggest a finely balanced expression optimum reached in highly permissive Huh7 cells, with even higher levels leading to a nearly complete breakdown of HCV replication, likely due to a dysregulation of bile acid and cholesterol metabolism. Our unbiased expression-profiling approach, hence, led to the identification of four host cellular genes that contribute to HCV permissiveness in Huh7 cells. These findings add to an improved understanding of the molecular underpinnings of the strict host cell tropism of HCV.

Efficient replication systems for hepatitis C virus using a new human hepatoma cell line

2009 ◽  
Vol 146 (1-2) ◽  
pp. 41-50 ◽  
Author(s):  
Nobuyuki Kato ◽  
Kyoko Mori ◽  
Ken-ichi Abe ◽  
Hiromichi Dansako ◽  
Misao Kuroki ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Cell Line ◽  
Hepatoma Cell ◽  
Hepatoma Cell Line ◽  
Human Hepatoma ◽  
Human Hepatoma Cell ◽  
Human Hepatoma Cell Line ◽  
Replication Systems ◽  
Efficient Replication

scholarly journals Highly Permissive Cell Lines for Subgenomic and Genomic Hepatitis C Virus RNA Replication

2002 ◽  
Vol 76 (24) ◽  
pp. 13001-13014 ◽  
Author(s):  
Keril J. Blight ◽  
Jane A. McKeating ◽  
Charles M. Rice
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Cell Lines ◽  
Hepatoma Cell ◽  
Single Amino Acid ◽  
Prolonged Treatment ◽  
Hepatoma Cell Line ◽  
Acceptor Site ◽  
Adaptive Mutations ◽  
Cellular Environment

ABSTRACT Hepatitis C virus (HCV) replication appears to be restricted to the human hepatoma cell line Huh-7, indicating that a favorable cellular environment exists within these cells. Although adaptive mutations in the HCV nonstructural proteins typically enhance the replicative capacity of subgenomic replicons in Huh-7 cells, replication can only be detected in a subpopulation of these cells. Here we show that self-replicating subgenomic RNA could be eliminated from Huh-7 clones by prolonged treatment with alpha interferon (IFN-α) and that a higher frequency of cured cells could support both subgenomic and full-length HCV replication. The increased permissiveness of one of the cured cell lines allowed us to readily detect HCV RNA and antigens early after RNA transfection, eliminating the need for selection of replication-positive cells. We also demonstrate that a single amino acid substitution in NS5A is sufficient for establishing HCV replication in a majority of cured cells and that the major phosphate acceptor site of subtype 1b NS5A is not essential for HCV replication.

scholarly journals Hepatitis C virus infection of human hepatoma cell line 7721 in vitro

2001 ◽  
Vol 7 (5) ◽  
pp. 685 ◽  
Author(s):  
Zhi-Qiang Song ◽  
Fei Hao ◽  
Feng Min ◽  
Qiao-Yu Ma ◽  
Guo-Dong Liu
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Virus Infection ◽  
Cell Line ◽  
Hepatoma Cell ◽  
Hepatoma Cell Line ◽  
Human Hepatoma ◽  
Hepatitis C Virus Infection ◽  
Human Hepatoma Cell

scholarly journals Targeting Autophagy Augments Berberine-Mediated Cell Death in Human Hepatoma Cells Harboring Hepatitis C Virus RNA

Cells ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 908 ◽  
Author(s):  
Chen-Jei Tai ◽  
Alagie Jassey ◽  
Ching-Hsuan Liu ◽  
Cheng-Jeng Tai ◽  
Christopher D. Richardson ◽  
...  
Keyword(s):  
Cell Death ◽  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Hepatoma Cell ◽  
Treatment Strategies ◽  
Hepatoma Cells ◽  
Hcv Rna ◽  
Human Hepatoma Cells ◽  
Subgenomic Replicon ◽  
Pharmacological Inhibition

Hepatocellular carcinoma (HCC), including hepatitis C virus (HCV)-induced HCC, is a deadly disease highly refractory to chemotherapy, thus requiring the continuous identification of novel treatment strategies. Berberine (BBR) has been previously reported to inhibit hepatoma cell growth, but the main type of cell death elicited by BBR, and whether the alkaloid can inhibit hepatoma cells carrying HCV genomes, is unclear. Herein, we show that BBR treatment induced a biphasic cell death irrespective of the presence of HCV subgenomic replicon RNA, first triggering apoptosis that then progressed to necrosis between 24 and 48 h post-treatment. Furthermore, BBR treatment potentiated the HCV replicon-induced reactive oxygen species (ROS) production, inhibition of which with an antioxidant attenuated the cell death that was elicited by BBR in these cells. Moreover, BBR dampened the autophagic response in HCV RNA-positive or negative hepatoma cells, and pharmacological inhibition of autophagy conversely augmented the BBR-induced cell death. Finally, BBR inhibited the growth of Huh-7 cells that were persistently infected with the full-length genome HCV particles, and concomitant pharmacological inhibition of autophagy potentiated the killing of these cells by BBR. Our findings suggest that combining BBR with the inhibition of autophagy could be an attractive treatment strategy against HCC, irrespective of the presence of the HCV genome.

scholarly journals Hepatitis C Virus Infection Induces Apoptosis through a Bax-Triggered, Mitochondrion-Mediated, Caspase 3-Dependent Pathway

2008 ◽  
Vol 82 (21) ◽  
pp. 10375-10385 ◽  
Author(s):  
Lin Deng ◽  
Tetsuya Adachi ◽  
Kikumi Kitayama ◽  
Yasuaki Bungyoku ◽  
Sohei Kitazawa ◽  
...  
Keyword(s):  
Cell Death ◽  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Er Stress ◽  
Caspase 3 ◽  
Nuclear Translocation ◽  
Experimental System ◽  
Hcv Infection ◽  
Hcv Rna ◽  
Dependent Pathway

ABSTRACT We previously reported that cells harboring the hepatitis C virus (HCV) RNA replicon as well as those expressing HCV NS3/4A exhibited increased sensitivity to suboptimal doses of apoptotic stimuli to undergo mitochondrion-mediated apoptosis (Y. Nomura-Takigawa, et al., J. Gen. Virol. 87:1935-1945, 2006). Little is known, however, about whether or not HCV infection induces apoptosis of the virus-infected cells. In this study, by using the chimeric J6/JFH1 strain of HCV genotype 2a, we demonstrated that HCV infection induced cell death in Huh7.5 cells. The cell death was associated with activation of caspase 3, nuclear translocation of activated caspase 3, and cleavage of DNA repair enzyme poly(ADP-ribose) polymerase, which is known to be an important substrate for activated caspase 3. These results suggest that HCV-induced cell death is, in fact, apoptosis. Moreover, HCV infection activated Bax, a proapoptotic member of the Bcl-2 family, as revealed by its conformational change and its increased accumulation on mitochondrial membranes. Concomitantly, HCV infection induced disruption of mitochondrial transmembrane potential, followed by mitochondrial swelling and release of cytochrome c from mitochondria. HCV infection also caused oxidative stress via increased production of mitochondrial superoxide. On the other hand, HCV infection did not mediate increased expression of glucose-regulated protein 78 (GRP78) or GRP94, which are known as endoplasmic reticulum (ER) stress-induced proteins; this result suggests that ER stress is not primarily involved in HCV-induced apoptosis in our experimental system. Taken together, our present results suggest that HCV infection induces apoptosis of the host cell through a Bax-triggered, mitochondrion-mediated, caspase 3-dependent pathway(s).

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