Hepatitis C Virus Regulates Transforming Growth Factor β1 Production Through the Generation of Reactive Oxygen Species in a Nuclear Factor κB–Dependent Manner

Lin, Wenyu; Tsai, Wei‐Lun; Shao, Run–Xuan; Wu, Guoyang; Peng, Leilei; Barlow, Lydia L.; Chung, Woo Jin; Zhang, Leiliang; Zhao, Hong; Jang, Jun‐Bock; Chung, Raymond T.

doi:10.1053/j.gastro.2010.03.008

Cited by 171 publications

(176 citation statements)

References 35 publications

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“…S6 D and E), suggesting that the function of HCV in regulating E-cadherin expression and inducing EMT relies, at least partially, on TGF-β activation. The induction of TGF-β by HCV has been previously reported (25). In addition, treatment of cells with E-cadherin blocking antibody had no effect on VIM and FN1 expression (Fig.…”

Section: Hcv Infection Represses E-cadherin Expression and Induces Emtmentioning

confidence: 69%

Hepatitis C virus depends on E-cadherin as an entry factor and regulates its expression in epithelial-to-mesenchymal transition

Sodroski

Lowey

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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Hepatitis C virus (HCV) enters the host cell through interactions with a cascade of cellular factors. Although significant progress has been made in understanding HCV entry, the precise mechanisms by which HCV exploits the receptor complex and host machinery to enter the cell remain unclear. This intricate process of viral entry likely depends on additional yet-to-be-defined cellular molecules. Recently, by applying integrative functional genomics approaches, we identified and interrogated distinct sets of host dependencies in the complete HCV life cycle. Viral entry assays using HCV pseudoparticles (HCVpps) of various genotypes uncovered multiple previously unappreciated host factors, including E-cadherin, that mediate HCV entry. E-cadherin silencing significantly inhibited HCV infection in Huh7.5.1 cells, HepG2/miR122/CD81 cells, and primary human hepatocytes at a postbinding entry step. Knockdown of E-cadherin, however, had no effect on HCV RNA replication or internal ribosomal entry site (IRES)-mediated translation. In addition, an E-cadherin monoclonal antibody effectively blocked HCV entry and infection in hepatocytes. Mechanistic studies demonstrated that E-cadherin is closely associated with claudin-1 (CLDN1) and occludin (OCLN) on the cell membrane. Depletion of E-cadherin drastically diminished the cell-surface distribution of these two tight junction proteins in various hepatic cell lines, indicating that E-cadherin plays an important regulatory role in CLDN1/OCLN localization on the cell surface. Furthermore, loss of E-cadherin expression in hepatocytes is associated with HCVinduced epithelial-to-mesenchymal transition (EMT), providing an important link between HCV infection and liver cancer. Our data indicate that a dynamic interplay among E-cadherin, tight junctions, and EMT exists and mediates an important function in HCV entry.epatitis C virus (HCV), a member of the Hepacivirus genus in the Flaviviridae family, is an enveloped, single-stranded and positive-sense RNA virus that infects humans and other higher primates, with a selective tropism to the liver. The virus is estimated to infect 2.8% of the world's population (1), and has evolved into a major causative agent of end-stage liver diseases, including cirrhosis and hepatocellular carcinoma (HCC) (2). Chronic hepatitis C is also the leading indication for liver transplantation in the United States (3). To date, a protective vaccine is not available. Current therapeutic regimens applying direct-acting antivirals with or without ribavirin have made it possible to cure the majority of patients with HCV (4).HCV infection gains chronicity in ∼75-85% of patients, facilitated by various viral mechanisms to evade host immune responses and exploit the cellular machinery (5). The replication cycle of HCV in the host cell consists of multiple sequential steps, beginning with the lipo-viro-particle binding and entry, followed by viral RNA translation and replication, packaging and assembly of the virion, and finally secretion from host cells (6, 7). Each...

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Section: Hcv Infection Represses E-cadherin Expression and Induces Emtmentioning

confidence: 69%

Hepatitis C virus depends on E-cadherin as an entry factor and regulates its expression in epithelial-to-mesenchymal transition

Sodroski

Lowey

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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“…The multiplicity of infection of JFH1 in our experiments was 0.2. We found that JFH1-infected Huh7.5.1 cells were about 50% infected at 48 h and at least 95% infected at day 6 by HCV core immunofluorescence staining both in this study and in our previous report (30). (B) Full-length GT1a, GT1b, GT3a, or GT3b NS5A; NS4B constructs; or the empty vector control, pCAGGS-V5/His, was cotransfected with pISRE-luc and pRL-TK into Huh7.…”

Section: Resultsmentioning

confidence: 95%

“…The Huh7.5.1 cells were infected with HCV JFH1 as previously described (30,31,45). The infectious GT1 and GT3 NS5A recombinant viruses were produced from recombinant DNA constructs, as previously reported (39).…”

Section: Cell Cultures and Infectious Virusesmentioning

confidence: 99%

Hepatitis C Virus NS5A Disrupts STAT1 Phosphorylation and Suppresses Type I Interferon Signaling

Kumthip

Chusri

Jilg

et al. 2012

J Virol

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Responses to alpha interferon (IFN-␣)-based treatment are dependent on both host and viral factors and vary markedly among patients infected with different hepatitis C virus (HCV) genotypes (GTs).Patients infected with GT3 viruses consistently respond better to IFN treatment than do patients infected with GT1 viruses. The mechanisms underlying this difference are not well understood. In this study, we sought to determine the effects of HCV NS5A proteins from different genotypes on IFN signaling. We found that the overexpression of either GT1 or GT3 NS5A proteins significantly inhibited IFN-induced IFN-stimulated response element (ISRE) signaling, phosphorylated STAT1 (P-STAT1) levels, and IFN-stimulated gene (ISG) expression compared to controls. GT1 NS5A protein expression exhibited stronger inhibitory effects on IFN signaling than did GT3 NS5A protein expression. Furthermore, GT1 NS5A bound to STAT1 with a higher affinity than did GT3 NS5A. Domain mapping revealed that the C-terminal region of NS5A conferred these inhibitory effects on IFN signaling. The overexpression of HCV NS5A increased HCV replication levels in JFH1-infected cells through the further reduction of levels of P-STAT1, ISRE signaling, and downstream ISG responses. We demonstrated that the overexpression of GT1 NS5A proteins resulted in less IFN responsiveness than did the expression of GT3 NS5A proteins through stronger binding to STAT1. We confirmed that GT1 NS5A proteins exerted stronger IFN signaling inhibition than did GT3 NS5A proteins in an infectious recombinant JFH1 virus. The potent antiviral NS5A inhibitor BMS-790052 did not block NS5A-mediated IFN signaling suppression in an overexpression model, suggesting that NS5A's contributions to replication are independent of its subversive action on IFN. We propose a model in which the binding of the C-terminal region of NS5A to STAT1 leads to decreased levels of P-STAT1, ISRE signaling, and ISG transcription and, ultimately, to preferential GT1 resistance to IFN treatment. More than 170 million individuals are infected with hepatitis C virus (HCV) worldwide, and the disease often progresses to chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma (1, 33). Alpha interferon (IFN-␣) has been the backbone of therapy for hepatitis C virus infection. Unfortunately, a number of patients do not respond well to therapy (9,15,20,40). The response rates to IFN therapy are also markedly different among patients infected with different HCV genotypes (GTs). Patients infected with HCV GT1 demonstrate sustained virological response (SVR) rates of 38 to 52%, whereas those infected with GT3 achieve higher SVR rates of 66 to 88% (5, 15, 34). However, the precise mechanisms for HCV GT1 hyporesponsiveness are still not fully understood (38, 40). Several HCV proteins, including core and NS5A, have been demonstrated to contribute to the lack of a response of patients with HCV infection to IFN treatment (35,38,40,47). We have previously reported that HCV replication and core protein expression decrease...

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“…Proteins were obtained, separated, and transferred to nitrocellulose membranes as reported previously (26,27). The target proteins were detected with the following specific primary antibodies: mouse anti-HCV core protein (C7-50; Fisher Scientific); mouse anti-actin, rabbit anti-EFTUD2, rabbit anti-RIG-I, rabbit anti-MDA5, rabbit anti-TBK1, rabbit anti-MxA1, and rabbit anti-OAS1 (Sigma Life Science and Biochemicals); and rabbit anti-IRF3 and anti-phospho-IRF-3 (Ser396) (Cell Signaling Technology).…”

Section: Western Blottingmentioning

confidence: 99%

EFTUD2 Is a Novel Innate Immune Regulator Restricting Hepatitis C Virus Infection through the RIG-I/MDA5 Pathway

Zhu

Xiao

Hong

et al. 2015

J Virol

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The elongation factor Tu GTP binding domain-containing protein 2 (EFTUD2) was identified as an anti-hepatitis C virus (HCV) host factor in our recent genome-wide small interfering RNA (siRNA) screen. In this study, we sought to further determine EFTUD2's role in HCV infection and investigate the interaction between EFTUD2 and other regulators involved in HCV innate immune (RIG-I, MDA5, TBK1, and IRF3) and JAK-STAT1 pathways. We found that HCV infection decreased the expression of EFTUD2 and the viral RNA sensors RIG-I and MDA5 in HCV-infected Huh7 and Huh7.5.1 cells and in liver tissue from in HCVinfected patients, suggesting that HCV infection downregulated EFTUD2 expression to circumvent the innate immune response. H epatitis C virus (HCV) poses a threat to public health by infecting approximately 170 million people worldwide and causing chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma (1, 2). Fifty to ninety percent of acute infections become chronic due to failure to mount a productive immune response to clear the virus. The innate immune system is the first line of defense responsible for recognizing viral pathogens and is therefore one of the crucial elements in determining the outcome of HCV infection.It is known that HCV RNA is recognized by the combined actions of protein kinase R (PKR), retinoic acid-inducible gene 1 (RIG-I), and Toll-like receptor 3 (TLR3) after viral entry into host cells (3-5). Pathogen recognition triggers downstream signaling to activate transcription factors, such as interferon (IFN) regulatory factors (IRFs), to induce type I interferon secretion and stimulation of the JAK-STAT signaling pathway, leading to the expression of IFN-stimulated genes (ISGs), which presumptively mediate control of viral replica-

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Hepatitis C Virus Regulates Transforming Growth Factor β1 Production Through the Generation of Reactive Oxygen Species in a Nuclear Factor κB–Dependent Manner

Cited by 171 publications

References 35 publications

Hepatitis C virus depends on E-cadherin as an entry factor and regulates its expression in epithelial-to-mesenchymal transition

Hepatitis C virus depends on E-cadherin as an entry factor and regulates its expression in epithelial-to-mesenchymal transition

Hepatitis C Virus NS5A Disrupts STAT1 Phosphorylation and Suppresses Type I Interferon Signaling

EFTUD2 Is a Novel Innate Immune Regulator Restricting Hepatitis C Virus Infection through the RIG-I/MDA5 Pathway

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