Direct, interferon-independent activation of the CXCL10 promoter by NF-κB and interferon regulatory factor 3 during hepatitis C virus infection

Jessica Brownell, Jacob Bruckner, Jessica Wagoner, Emmanuel Thomas, Yueh Ming Loo, Michael Gale, T. Jake Liang, Stephen J. Polyak

Research output: Contribution to journalArticle

48 Citations (Scopus)

Abstract

Hepatitis C virus (HCV) infection of hepatocytes leads to transcriptional induction of the chemokine CXCL10, which is considered an interferon (IFN)-stimulated gene. However, we have recently shown that IFNs are not required for CXCL10 induction in hepatocytes during acute HCV infection. Since the CXCL10 promoter contains binding sites for several proinflammatory transcription factors, we investigated the contribution of these factors to CXCL10 transcriptional induction during HCV infection in vitro. Wild-type and mutant CXCL10 promoter-luciferase reporter constructs were used to identify critical sites of transcriptional regulation. The proximal IFN-stimulated response element (ISRE) and NF-κB binding sites positively regulated CXCL10 transcription during HCV infection as well as following exposure to poly(I·C) (a Toll-like receptor 3 [TLR3] stimulus) and 5= poly(U) HCV RNA (a retinoic acid-inducible gene I [RIG-I] stimulus) from two viral genotypes. Conversely, binding sites for AP-1 and CCAAT/enhancer-binding protein β (C/EBP-β) negatively regulated CXCL10 induction in response to TLR3 and RIG-I stimuli, while only C/EBP-β negatively regulated CXCL10 during HCV infection. We also demonstrated that interferonregulatory factor 3 (IRF3) is transiently recruited to the proximal ISRE during HCV infection and localizes to the nucleus in HCV-infected primary human hepatocytes. Furthermore, IRF3 activated the CXCL10 promoter independently of type I or type III IFN signaling. The data indicate that sensing of HCV infection by RIG-I and TLR3 leads to direct recruitment of NF-κB and IRF3 to the CXCL10 promoter. Our study expands upon current knowledge regarding the mechanisms of CXCL10 induction in hepatocytes and lays the foundation for additional mechanistic studies that further elucidate the combinatorial and synergistic aspects of immune signaling pathways.

Original languageEnglish
Pages (from-to)1582-1590
Number of pages9
JournalJournal of Virology
Volume88
Issue number3
DOIs
StatePublished - Feb 1 2014

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Interferon Regulatory Factor-3
Hepatitis C virus
Virus Diseases
interferons
Hepacivirus
Interferons
promoter regions
Toll-Like Receptor 3
infection
hepatocytes
Hepatocytes
retinoic acid
Tretinoin
binding sites
response elements
Binding Sites
Response Elements
Genes
Toll-Like Receptor 5
genes

ASJC Scopus subject areas

  • Immunology
  • Virology

Cite this

Direct, interferon-independent activation of the CXCL10 promoter by NF-κB and interferon regulatory factor 3 during hepatitis C virus infection. / Brownell, Jessica; Bruckner, Jacob; Wagoner, Jessica; Thomas, Emmanuel; Loo, Yueh Ming; Gale, Michael; Liang, T. Jake; Polyak, Stephen J.

In: Journal of Virology, Vol. 88, No. 3, 01.02.2014, p. 1582-1590.

Research output: Contribution to journalArticle

Brownell, Jessica ; Bruckner, Jacob ; Wagoner, Jessica ; Thomas, Emmanuel ; Loo, Yueh Ming ; Gale, Michael ; Liang, T. Jake ; Polyak, Stephen J. / Direct, interferon-independent activation of the CXCL10 promoter by NF-κB and interferon regulatory factor 3 during hepatitis C virus infection. In: Journal of Virology. 2014 ; Vol. 88, No. 3. pp. 1582-1590.
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