Journal of Gastroenterology

, Volume 41, Issue 8, pp 750–757

Negative regulation of intracellular hepatitis C virus replication by interferon regulatory factor 3

  • Tsuyoshi Yamashiro
  • Naoya Sakamoto
  • Masayuki Kurosaki
  • Nobuhiko Kanazawa
  • Yoko Tanabe
  • Mina Nakagawa
  • Cheng-Hsin Chen
  • Yasuhiro Itsui
  • Tomoyuki Koyama
  • Yoshie Takeda
  • Shinya Maekawa
  • Nobuyuki Enomoto
  • Hiroshi Sakugawa
  • Mamoru Watanabe
Article

DOI: 10.1007/s00535-006-1842-x

Cite this article as:
Yamashiro, T., Sakamoto, N., Kurosaki, M. et al. J Gastroenterol (2006) 41: 750. doi:10.1007/s00535-006-1842-x
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Abstract

Background

Interferon regulatory factor (IRF)-3 plays an important role in initiating cellular interferon-stimulated gene-mediated antiviral responses. In the present study, we evaluated the effects of IRF-3 expression and activation on intracellular hepatitis C virus (HCV) replication using an HCV replicon system.

Methods

An HCV replicon was constructed that expressed a neomycin-selectable chimeric firefly luciferase reporter protein. A small interfering (si) RNA oligonucleotide directed against IRF-3 mRNA was designed and synthesized. A eukaryote expression plasmid vector was constructed that expressed IRF-3 mRNA under control of the cytomegalovirus early promoter/enhancer. To evaluate transcriptional activity of the interferon-stimulated genes, a reporter vector was used that expressed firefly luciferase under control of the interferon-stimulated response element (ISRE).

Results

The baseline expression of IRF-3 did not significantly differ between cells with and without expression of the replicon. Transfection of an IRF-3 expression plasmid into the cells raised the ISRE-luciferase activities. The increase of ISRE activity was significantly more potent in the replicon-expressing cells than in cells without replicon expression. Concomitantly, the overexpression of IRF-3 suppressed HCV replication levels. In contrast, siRNA knockdown of IRF-3 suppressed ISRE activity by 38% ± 2%. Interestingly, the suppression of IRF-3 resulted in a significant increase of HCV replication, by up to twofold, depending on the IRF-3 suppression levels.

Conclusions

IRF-3 negatively regulated intracellular HCV replication, and was partially activated in cells that expressed the HCV replicon. Thus, IRF-3 is a key molecule controlling HCV replication through modulation of host interferon gene responses.

Key words

hepatitis C virus interferon regulatory factor 3 

Copyright information

© Springer-Verlag Tokyo 2006

Authors and Affiliations

  • Tsuyoshi Yamashiro
    • 1
    • 3
  • Naoya Sakamoto
    • 1
  • Masayuki Kurosaki
    • 1
  • Nobuhiko Kanazawa
    • 1
  • Yoko Tanabe
    • 1
  • Mina Nakagawa
    • 1
  • Cheng-Hsin Chen
    • 1
  • Yasuhiro Itsui
    • 1
  • Tomoyuki Koyama
    • 1
  • Yoshie Takeda
    • 1
  • Shinya Maekawa
    • 1
    • 2
  • Nobuyuki Enomoto
    • 2
  • Hiroshi Sakugawa
    • 3
  • Mamoru Watanabe
    • 1
  1. 1.Department of Gastroenterology and HepatologyTokyo Medical and Dental UniversityTokyoJapan
  2. 2.First Department of Internal MedicineUniversity of YamanashiChuoJapan
  3. 3.First Department of Internal MedicineSchool of Medicine, University of the RyukyusOkinawaJapan

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