Mechanism of HCV's resistance to IFN-α in cell culture involves expression of functional IFN-α receptor 1

Datta, Sibnarayan; Hazari, Sidhartha; Chandra, Partha K.; Σαμαρά, Μαρία; Poat, Bret; Gündüz, Feyza; Wimley, William C.; Hauser, Hansjörg; Köster, Mario; Lamaze, Christophe; Balart, Luis A.; Garry, Robert F.; Dash, Srikanta

doi:10.1186/1743-422x-8-351

Cited by 15 publications

(19 citation statements)

References 31 publications

(40 reference statements)

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“…In the present study, we also demonstrate that the expression levels of IFNAR1 and IFNAR2 are downregulated by overexpression of Set7 and are upregulated by knockdown of Set7. Recent research has demonstrated that STAT1 and STAT2 phosphorylation are impaired by downregulation of the expression of IFNAR1 and IFNAR2 (58). These results are in complete agreement with our data.…”

Section: Discussionsupporting

confidence: 83%

“…Many reports have demonstrated that these two receptors are critical for activation of the IFN-a/JAK/STAT pathway, and the reduction of the cell surface expression of IFN-a influences its antiviral response in many cells (56)(57)(58)(59). Thus, considering that Set7 is an upstream effector of STAT phosphorylation, we further determined whether Set7(WT) could influence the expression of IFNAR1 or IFNAR2.…”

Section: Set7 Downregulates the Expression Of Ifnarsmentioning

confidence: 99%

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Set7 Facilitates Hepatitis C Virus Replication via Enzymatic Activity–Dependent Attenuation of the IFN-Related Pathway

Han

Wang

Zhao

et al. 2015

The Journal of Immunology

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Hepatitis C virus (HCV) infection is a major cause of chronic liver disease, usually resulting in persistent infection involving hepatic steatosis, cirrhosis, and hepatocellular carcinoma via escape of the host’s immune response. Set7 is a lysine-specific methyltransferase that is involved in gene regulation and virus replication. However, the mechanism underlying the immune evasion between HCV and Set7 is not well understood. In this study, we observed that the expression of Set7 in Huh7.5.1 cells was upregulated by HCV infection, and high levels of Set7 expression were also found in the sera, PBMCs, and liver tissue of HCV patients relative to healthy individuals. Further investigation showed that Set7 enhanced HCV replication in an enzymatic activity–dependent manner. Moreover, our data showed that Set7 decreased the expression of virus-induced IFN and IFN-related effectors, such as dsRNA-activated protein kinase and 2′,5′-oligoadenylate synthetase. Further investigation suggested that Set7 suppressed the endogenous IFN expression by reducing the nuclear translocation of IFN regulatory factor 3/7 and the p65 subunit of NF-κB and reduced IFN-induced dsRNA-activated protein kinase and 2′,5′-oligoadenylate synthetase via attenuation of the phosphorylation of STAT1 and STAT2. Additionally, IFN receptors, including IFNAR1 and IFNAR2, which are located upstream of the JAK/STAT pathway, were reduced by Set7. Taken together, our results reveal that Set7 facilitates HCV replication through the attenuation of IFN signaling pathways and IFN-related effectors.

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Section: Discussionsupporting

confidence: 83%

Section: Set7 Downregulates the Expression Of Ifnarsmentioning

confidence: 99%

Set7 Facilitates Hepatitis C Virus Replication via Enzymatic Activity–Dependent Attenuation of the IFN-Related Pathway

Han

Wang

Zhao

et al. 2015

The Journal of Immunology

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“…In cell-HCV replicon systems that require passage of the cells, the mutations observed in HCV may be conditioned by mutations in the cells that coevolve with the HCV replicon (75,96,116,117). Furthermore, selection of a cellular IFN-␣ resistance determinant may render unnecessary the selection of viral modifications to achieve an equivalent phenotype.…”

Section: Discussionmentioning

confidence: 99%

Response of Hepatitis C Virus to Long-Term Passage in the Presence of Alpha Interferon: Multiple Mutations and a Common Phenotype

Perales

Beach

Gallego

et al. 2013

J Virol

172

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H epatitis C virus (HCV) infects an estimated 180 million people worldwide, and about 75% of newly infected patients progress toward a chronic infection, which constitutes a risk for severe liver diseases such as cirrhosis and hepatocarcinoma (1-4). HCV is a hepacivirus in the Flaviviridae family characterized by the error-prone replication and quasispecies dynamics typical of RNA viruses (2,(5)(6)(7). No vaccine is available to prevent HCV infections or disease, and the current standard of care treatment consists of the combination of pegylated alpha interferon (IFN-␣) and the purine nucleoside analogue ribavirin (1-␤-D-ribofuranosyl-1-H-1,2,4-triazole-3-carboxamide) (8-10). Type I interferons (IFNs) such as IFN-␣ are members of a family of cytokines that constitute key components of the innate immune response to viruses, and their induction results in an antiviral state of the cell and suppression of viral replication (11)(12)(13)(14). Ribavirin is currently used to treat a number of human viral infections, and it can display multiple mechanisms of action, including enhancement of Th1 antiviral immune responses, upregulation of IFN-stimulated genes (ISGs), depletion of GTP pools, or viral RNA mutagenesis (see reviews in references 15, 16 and 17). However, on average only about 60% of the chronically infected patients show a sustained virological response to treatment with IFN-␣ plus ribavirin that results in virus clearance (18-21). The molecular and physiological bases of the therapeutic activity of the current combination treatment with IFN-␣ plus ribavirin are poorly understood. It might be possible to establish new treatment protocols based on recently developed directly acting antiviral agents (DAAs), with or without .Highly variable viruses exploit a number of strategies to counteract selective constraints intended to prevent their replication (reviewed in reference 7). Mutations that confer resistance to DAAs generally map in the target protein or in a protein that interacts with the target (28-30). However, the complexity of the cellular IFN response pathway is expected to require greater diversity of viral resistance mutations. Current evidence suggests that the response of HCV to IFN-␣-based therapy is influenced by several host (i.e., interleukin-28B [IL-28B] gene polymorphisms) and viral genetic (i.e., viral genotype and population complexity) factors (31-37).The advent of cell culture systems for sustained replication of HCV offers new prospects to approach the evolutionary dynamics of HCV and the host cell-virus relationship, including the anti-HCV activity of IFN-␣. Using these systems, Garaigorta and Chisari documented that HCV-induced protein kinase R (PKR) phosphorylation inhibited translation of IFN-stimulated genes (ISGs) in infected hepatocytes (38). Here we describe the adaptation of the HCV replication system of genotype 2a (39-41) to perform serial passages of HCV in the Huh-7.5 hepatocyte cell line with sustained, efficient viral replication for at least 100 serial passages. This cell ...

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“…Total RNA was isolated from uninfected and HCV-infected Huh-7.5 cells by using the guanidinium thiocyanate (GITC) method. HCV quantification was carried out by using a reverse transcription-quantitative PCR (RT-qPCR) assay described previously (21). Briefly, 1 g of total cellular RNA was used to amplify the 5= untranslated region (UTR) of the HCV genome by using sense primer 5=-T CTTCACGCAGAAAGCGTCTA-3= (positions 60 to 80) (HCV/S) and antisense primer 5=-CGGTTCCGCAGACCACTATG-3= (positions 157 to 138) (HCV/AS).…”

Section: Methodsmentioning

confidence: 99%

“…Previously, we reported that a combined HCV-induced endoplasmic reticulum (ER) stress and autophagy response downregulates the expression of IFN-␣ receptor 1, which is why HCV replication in a persistently infected cell culture is not completely inhibited by IFN-␣ (20,21). In this study, we investigated virus and host cell interactions that impair RBV antiviral activity in a persistently HCV-infected cell culture system.…”

mentioning

confidence: 99%

Persistent Hepatitis C Virus Infection Impairs Ribavirin Antiviral Activity through Clathrin-Mediated Trafficking of Equilibrative Nucleoside Transporter 1

Panigrahi

Chandra

Ferraris

et al. 2015

J Virol

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Ribavirin (RBV) continues to be an important component of interferon-free hepatitis C treatment regimens, as RBV alone does not inhibit hepatitis C virus (HCV) replication effectively; the reason for this ineffectiveness has not been established. In this study, we investigated the RBV resistance mechanism using a persistently HCV-infected cell culture system. The antiviral activity of RBV against HCV was progressively impaired in the persistently infected culture, whereas interferon lambda 1 (IFN-1), a type III IFN, showed a strong antiviral response and induced viral clearance. We found that HCV replication in persistently infected cultures induces an autophagy response that impairs RBV uptake by preventing the expression of equilibrative nucleoside transporter 1 (ENT1). The Huh-7.5 cell line treated with an autophagy inducer, Torin 1, downregulated membrane expression of ENT1 and terminated RBV uptake. In contrast, the autophagy inhibitors hydroxychloroquine (HCQ), 3-methyladenine (3-MA), and bafilomycin A1 (BafA1) prevented ENT1 degradation and enhanced RBV antiviral activity. The HCV-induced autophagy response, as well as treatment with Torin 1, degrades clathrin heavy chain expression in a hepatoma cell line. Reduced expression of the clathrin heavy chain by HCV prevents ENT1 recycling to the plasma membrane and forces ENT1 to the lysosome for degradation. This study provides a potential mechanism for the impairment of RBV antiviral activity in persistently HCV-infected cell cultures and suggests that inhibition of the HCV-induced autophagy response could be used as a strategy for improving RBV antiviral activity against HCV infection. IMPORTANCEThe results from this work will allow a review of the competing theories of antiviral therapy development in the field of HCV virology. Ribavirin (RBV) remains an important component of interferon-free hepatitis C treatment regimens. The reason why RBV alone does not inhibit HCV replication effectively has not been established. This study provides a potential mechanism for why RBV antiviral activity is impaired in persistently HCV-infected cell cultures and suggests that inhibition of the HCV-induced autophagy response could be used as a strategy to increase RBV antiviral activity against HCV infection. Therefore, it is anticipated that this work would generate a great deal of interest, not only among virologists but also among the general public. H epatitis C virus (HCV) is estimated to infect Ͼ185 million people worldwide (1). Infection by HCV leads to a high likelihood of chronic liver disease, which often progresses to liver cirrhosis and hepatocellular carcinoma; HCV is therefore a major public health problem. Interferon alpha (IFN-␣) and ribavirin (RBV) (a guanosine analogue) have been used as standard therapy for chronic HCV infection for over a decade, with a sustained virologic response rate of 50% for genotype 1a virus. In 2011, two HCV-specific direct-acting antivirals (DAAs) targeting to NS3 protease (telaprevir and boceprevir) received FDA appro...

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Mechanism of HCV's resistance to IFN-α in cell culture involves expression of functional IFN-α receptor 1

Cited by 15 publications

References 31 publications

Set7 Facilitates Hepatitis C Virus Replication via Enzymatic Activity–Dependent Attenuation of the IFN-Related Pathway

Set7 Facilitates Hepatitis C Virus Replication via Enzymatic Activity–Dependent Attenuation of the IFN-Related Pathway

Response of Hepatitis C Virus to Long-Term Passage in the Presence of Alpha Interferon: Multiple Mutations and a Common Phenotype

Persistent Hepatitis C Virus Infection Impairs Ribavirin Antiviral Activity through Clathrin-Mediated Trafficking of Equilibrative Nucleoside Transporter 1

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