Intragenotypic JFH1 based recombinant hepatitis C virus produces high levels of infectious particles but causes increased cell death

Mateu, Guaniri; Donis, Ruben O.; Wakita, Takaji; Bukh, Jens; Grakoui, Arash

doi:10.1016/j.virol.2008.03.027

Cited by 56 publications

(69 citation statements)

References 49 publications

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“…Two recent reports indicated that full-length HCV model J6/JFH1 could induce apoptosis of infected Huh7.5 (49,50). This finding seemed to be inconsistent with our results that NS5A repressed apoptosis.…”

Section: Discussioncontrasting

confidence: 99%

“…However, in chronically HCV-infected patients, viral replication was usually at a low level. This was consistent with one of observations that with the infection time increasing, the viral replication, viral titer, and number of cell apoptosis all decreased (49). Besides, as a full-length HCV virus, J6/JFH1-induced cell apoptosis under acute infection conditions was probably due to a comprehensive effect resulting from all J6/JFH1-encoded viral proteins, as many reports have demonstrated that HCV-encoded proteins such as core, E1, E2, NS2, NS3, NS4A exerted both pro-and anti-apoptotic effect (51)(52)(53)(54)(55)(56).…”

Section: Discussionsupporting

confidence: 93%

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Hepatitis C Virus NS5A Activates the Mammalian Target of Rapamycin (mTOR) Pathway, Contributing to Cell Survival by Disrupting the Interaction between FK506-binding Protein 38 (FKBP38) and mTOR

Lü

Dong

Tong

et al. 2010

Journal of Biological Chemistry

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Hepatitis C virus (HCV) often establishes a persistent infection that most likely involves a complex host-virus interplay. We previously reported that the HCV nonstructural protein 5A (NS5A) bound to cellular protein FKBP38 and resulted in apoptosis suppression in human hepatoma cell line Huh7. In the present research we further found that NS5A increased phosphorylation levels of two mTOR-targeted substrates, S6K1 and 4EBP1, in Huh7 in the absence of serum. mTOR inhibitor rapamycin or NS5A knockdown blocked S6K1 and 4EBP1 phosphorylation increase in NS5A-Huh7 and HCV replicon cells, suggesting that NS5A specifically regulated mTOR activation. Overexpression of NS5A and FKBP38 mutants or FKBP38 knockdown revealed this mTOR activation was dependent on NS5A-FKBP38 interaction. Phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002 treatment in NS5A-Huh7 showed that the mTOR activation was independent of PI3K. Moreover, NS5A suppressed caspase 3 and poly(ADP-ribose) polymerase activation, which was abolished by NS5A knockdown or rapamycin, indicating NS5A inhibited apoptosis specifically through the mTOR pathway. Further analyses suggested that apoptotic inhibition exerted by NS5A via mTOR also required NS5A-FKBP38 interaction. Glutathione S-transferase pulldown and co-immunoprecipitation showed that NS5A disrupted the mTOR-FKBP38 association. Additionally, NS5A or FKBP38 mutants recovered the mTOR-FKBP38 interaction; this indicated that the impairment of mTOR-FKBP38 association was dependent on NS5A-FKBP38 binding. Collectively, our data demonstrate that HCV NS5A activates the mTOR pathway to inhibit apoptosis through impairing the interaction between mTOR and FKBP38, which may represent a pivotal mechanism for HCV persistence and pathogenesis.

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Section: Discussioncontrasting

confidence: 99%

Section: Discussionsupporting

confidence: 93%

Hepatitis C Virus NS5A Activates the Mammalian Target of Rapamycin (mTOR) Pathway, Contributing to Cell Survival by Disrupting the Interaction between FK506-binding Protein 38 (FKBP38) and mTOR

Lü

Dong

Tong

et al. 2010

Journal of Biological Chemistry

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“…HCV-associated apoptosis involves two pathways: an immune response-associated, death receptor-mediated (extrinsic) pathway (Zhu et al, 2007) and a mitochondrion-mediated (intrinsic) pathway (Deng et al, 2008). By using an in vitro HCV infection system, we and other groups have observed that apoptosis is induced in Huh-7.5 cells in response to HCV infection (Deng et al, 2008;Mateu et al, 2008;Walters et al, 2009). Moreover, HCV-induced apoptosis was demonstrated in vivo by using the immunodeficient chimeric SCID/ Alb-uPA mouse model where immune response-dependent apoptosis can be discounted (Joyce et al, 2009).…”

Section: Introductionmentioning

confidence: 93%

HCV upregulates Bim through the ROS/JNK signalling pathway, leading to Bax-mediated apoptosis

Deng

Chen

Tanaka

et al. 2015

Journal of General Virology

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We previously reported that hepatitis C virus (HCV) infection induces Bax-triggered, mitochondrion-mediated apoptosis by using the HCV J6/JFH1 strain and Huh-7.5 cells. However, it was still unclear how HCV-induced Bax activation. In this study, we showed that the HCV-induced activation and mitochondrial accumulation of Bax were significantly attenuated by treatment with a general antioxidant, N-acetyl cysteine (NAC), or a specific c-Jun N-terminal kinase (JNK) inhibitor, SP600125, with the result suggesting that the reactive oxygen species (ROS)/JNK signalling pathway is upstream of Bax activation in HCV-induced apoptosis. We also demonstrated that HCV infection transcriptionally activated the gene for the proapoptotic protein Bim and the protein expression of three major splice variants of Bim (Bim EL , Bim L and Bim S ). The HCV-induced increase in the Bim mRNA and protein levels was significantly counteracted by treatment with NAC or SP600125, suggesting that the ROS/JNK signalling pathway is involved in Bim upregulation. Moreover, HCV infection led to a marked accumulation of Bim on the mitochondria to facilitate its interaction with Bax. On the other hand, downregulation of Bim by siRNA (small interfering RNA) significantly prevented HCV-mediated activation of Bax and caspase 3. Taken together, these observations suggest that HCV-induced ROS/JNK signalling transcriptionally activates Bim expression, which leads to Bax activation and apoptosis induction.

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“…This observation led us to ask what happens to infected cells following cell cycle arrest. Other viruses that cause G 2 arrest (e.g., bocavirus) may induce apoptosis (4), and a number of studies have suggested that infection of cells with either JFH1 virus or chimeric genotype 2 viruses that are based on JFH1 is associated with apoptosis (7,22,38). The intragenotypic J6/JFH1 chimera has previously been shown to induce higher levels of apoptosis than the parent JFH1 virus (22).…”

Section: Cell Cycle Analysis Of Hcv-infected Cellsmentioning

confidence: 99%

Hepatitis C Virus Infection Causes Cell Cycle Arrest at the Level of Initiation of Mitosis

Kannan

Hensley

Evers

et al. 2011

J Virol

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Chronic infection with the hepatitis C virus (HCV) is associated with increased risk for hepatocellular carcinoma (HCC). Chronic immune-mediated inflammation is likely to be an important factor in the development of HCV-associated HCC, but direct effects of HCV infection on the host cell cycle may also play a role.Although overexpression studies have revealed multiple interactions between HCV-encoded proteins and host cell cycle regulators and tumor suppressor proteins, the relevance of these observations to HCV-associated liver disease is not clear. We determined the net effect of these interactions on regulation of the cell cycle in the context of virus infection. Flow cytometry of HCV-infected carboxyfluorescein succinimidyl ester-labeled hepatoma cells indicated a slowdown in proliferation that correlated with abundance of viral antigen. A decrease in the proportions of infected cells in G 1 and S phases with an accumulation of cells in G 2 /M phase was observed, compared to mock-infected controls. Dramatic decreases in markers of mitosis, such as phosphohistone H3, in infected cells suggested a block to mitotic entry. In common with findings described in the published literature, we observed caspase 3 activation, suggesting that cell cycle arrest is associated with apoptosis. Differences were observed in patterns of cell cycle disturbance and levels of apoptosis with different strains of HCV. However, the data suggest that cell cycle arrest at the interface of G 2 and mitosis is a common feature of HCV infection.Chronic infection with hepatitis C virus (HCV) is associated with an increased risk for hepatocellular carcinoma (HCC) (8). Typically, cancer only develops after several decades of infection. Although the incidence of newly acquired HCV infections has decreased over the past 20 years, the incidence of HCVassociated HCC is increasing significantly as the infected population ages. Liver cancer associated with chronic HCV infection will, thus, be a significant public health burden for years to come. A greater understanding of the mechanisms by which chronic HCV infection leads to HCC will be critical for the development of improved therapies.HCV has high genetic diversity and has been classified into six major genotypes that differ in their geographical distributions and natural history (33). Globally, infection with genotype 1 is the most common. Currently, only the genotype 1 and 2 HCV genomes have been propagated in cell culture.The mechanisms by which HCV infection leads to HCC are unclear. HCV has an RNA genome with an exclusively cytoplasmic life cycle. Since HCV-associated HCC typically develops in the setting of fibrosis and cirrhosis, HCC development may be driven at least in part by chronic immune-mediated inflammation. However, in vitro studies have revealed multiple interactions between HCV-encoded proteins and host cell cycle regulators and tumor suppressor proteins (24). For example, in vitro studies have shown that three distinct HCV proteins, core (13), NS3 (12), and NS5A (14,20,29), in...

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Intragenotypic JFH1 based recombinant hepatitis C virus produces high levels of infectious particles but causes increased cell death

Cited by 56 publications

References 49 publications

Hepatitis C Virus NS5A Activates the Mammalian Target of Rapamycin (mTOR) Pathway, Contributing to Cell Survival by Disrupting the Interaction between FK506-binding Protein 38 (FKBP38) and mTOR

Hepatitis C Virus NS5A Activates the Mammalian Target of Rapamycin (mTOR) Pathway, Contributing to Cell Survival by Disrupting the Interaction between FK506-binding Protein 38 (FKBP38) and mTOR

HCV upregulates Bim through the ROS/JNK signalling pathway, leading to Bax-mediated apoptosis

Hepatitis C Virus Infection Causes Cell Cycle Arrest at the Level of Initiation of Mitosis

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