Role of ISGF3 in modulating the anti-hepatitis B virus activity of interferon-alpha in vitro.

Abstract

BACKGROUND AND AIM:

Although interferon-alpha (IFN-alpha) is an effective treatment for hepatitis B virus (HBV) infection, its precise mechanism of action has not been identified. In this study, we investigated the role of signal transduction pathways in the activation of anti-HBV responses mediated by IFN-alpha.

METHODS:

Using an oligo microarray, we found that four genes in the IFN-alpha signal pathway were markedly upregulated by IFN-alpha in human hepatoma cells regardless of whether they had been transfected with a plasmid containing the HBV genome: signal transducers and activators of transcription 1 (STAT1), interferon regulatory factor-9 (IRF-9, also called ISGF3gamma or P48), IFN-alpha-inducible protein 15 (IFI-15) and IFN-alpha-inducible protein 6-16 (IFI-6-16). We also investigated the role of IFN-stimulated gene factor3 (ISGF3) complex in IFN-alpha-mediated anti-HBV responses in human hepatoma cells by measuring the mRNA of the three genes within ISGF3 (STAT1, STAT2 and IRF-9) using semiquantitative reverse-transcription PCR (RT-PCR), and expression of the three proteins by western blot, and the mRNA and protein of dsRNA-dependent protein kinase (PKR).

RESULTS:

STAT1, STAT2, IRF-9 and PKR mRNA as well as protein levels were upregulated by IFN-alpha treatment. When cells were pretreated with genistein, STAT1, STAT2 and IRF-9 mRNA levels remained unchanged after IFN-alpha stimulation, but PKR mRNA levels decreased, and the expression of the STAT1, P-STAT2, IRF-9 and PKR proteins decreased. Levels of HBV DNA decreased in the supernatants of cells treated with IFN-alpha, while ISGF3 levels increased. The quantity of HBV DNA remained unchanged by pretreating with genistein.

CONCLUSIONS:

These observations suggested that the Janus tyrosine kinase-STAT (JAK-STAT) pathway may play a major role in mediating the effects of IFN-alpha against HBV, and that ISGF3 might be a key factor.

• Authors: Quan Zhang, Yan Wang, Lai Wei, Dong Jiang, Jiang Hua Wang, Hui Ying Rao, Ling Zhu, Hongsong Chen, Ran Fei, Xu Cong
• Journal: Journal of gastroenterology and hepatology (J Gastroenterol Hepatol) Vol. 23 Issue 11 Pg. 1747-61 (Nov 2008) ISSN: 1440-1746 [Electronic] Australia
• PMID: 17559358 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Antiviral Agents
• Cytokines
• DNA, Viral
• Hepatitis B Surface Antigens
• Hepatitis B e Antigens
• IFI6 protein, human
• IRF9 protein, human
• Interferon alpha-2
• Interferon-Stimulated Gene Factor 3, gamma Subunit
• Interferon-alpha
• Mitochondrial Proteins
• Protein Kinase Inhibitors
• RNA, Messenger
• Recombinant Proteins
• STAT1 Transcription Factor
• STAT1 protein, human
• STAT2 Transcription Factor
• STAT2 protein, human
• Ubiquitins
• ISG15 protein, human
• Genistein
• Janus Kinases
• eIF-2 Kinase

Topics

• Antiviral Agents (pharmacology)
• Cell Line, Tumor
• Cytokines (metabolism)
• DNA, Viral (biosynthesis)
• Gene Expression Profiling (methods)
• Genistein (pharmacology)
• Hepatitis B Surface Antigens (metabolism)
• Hepatitis B e Antigens (metabolism)
• Hepatitis B virus (drug effects, genetics, immunology)
• Hepatocytes (drug effects, immunology, virology)
• Humans
• Interferon alpha-2
• Interferon-Stimulated Gene Factor 3, gamma Subunit (genetics, metabolism)
• Interferon-alpha (pharmacology)
• Janus Kinases (antagonists & inhibitors, metabolism)
• Mitochondrial Proteins (metabolism)
• Oligonucleotide Array Sequence Analysis
• Phosphorylation
• Protein Kinase Inhibitors (pharmacology)
• RNA, Messenger (metabolism)
• Recombinant Proteins
• STAT1 Transcription Factor (metabolism)
• STAT2 Transcription Factor (metabolism)
• Signal Transduction (drug effects, genetics)
• Time Factors
• Transfection
• Ubiquitins (metabolism)
• Virus Replication (drug effects)
• eIF-2 Kinase (metabolism)