[Effect of hepatitis B virus X protein on suppressor of cytokine signaling-1 expression].

Abstract

OBJECTIVE:

To investigate the effect of hepatitis B virus-encoded X protein (HBx) on the expression of host-encoded suppressor of cytokine signaling-1 (SOCS-1) and to explore the possibility of an underlying mechanism involving modulation of CpG island methylation in the SOCS-1 gene promoter.

METHODS:

The immortalized human derived non-tumor liver cell line QSG7701 was transfected with a recombinant HBx plasmid (pcDNA-X) or an empty vector control plasmid (pcDNA3.0) and stably transfected clones were selected by G418 resistance screening. Untransfected cells served as negative controls. Expression of SOCS-1 mRNA and protein was detected by real-time quantitative PCR and western blotting. The methylation status of SOCS-1 was detected by methylation-specific PCR (MSP). The significance of intergroup differences was analyzed by one-way ANOVA or pairwise comparison with post-hoc LSD test.

RESULTS:

SOCS-1 mRNA level was significantly lower in the pcDNA-X/QSG7701 cells compared to that in the pcDNA3.0/QSG7701 and untransfected cells (0.3249+/-0.0536 vs. 1.0543+/-0.1937 and 1.00; F = 19.6, P = 0.042). SOCS-1 protein level was similarly lower in the pcDNA-X/QSG7701 cells (0.1496+/-0.0106 vs. 0.1984+/-0.0438 and 0.2152+/-0.0816; F = 19.4, P = 0.048). The SOCS-1 promoter region showed methylation only in the pcDNA-X/QSG7701 cells.

CONCLUSION:

HBx-expressing human hepatocytes have down-regulated SOCS-1 expression, both at the mRNA and protein levels, and this effect corresponds to increased methylation in the SOCS-1 promoter region harboring CpG islands.

• Authors: Xiao-ling Song, Guo-zhen Liu, De-ming Tan, Yan-yan Li
• Journal: Zhonghua gan zang bing za zhi = Zhonghua ganzangbing zazhi = Chinese journal of hepatology (Zhonghua Gan Zang Bing Za Zhi) Vol. 21 Issue 10 Pg. 723-7 (Oct 2013) ISSN: 1007-3418 [Print] China
• PMID: 24331627 (Publication Type: Journal Article)

Chemical References

• RNA, Messenger
• SOCS1 protein, human
• Suppressor of Cytokine Signaling 1 Protein
• Suppressor of Cytokine Signaling Proteins
• Trans-Activators
• Viral Regulatory and Accessory Proteins
• hepatitis B virus X protein

Topics

• Cell Line
• CpG Islands
• DNA Methylation
• Humans
• Plasmids
• Promoter Regions, Genetic
• RNA, Messenger (genetics)
• Suppressor of Cytokine Signaling 1 Protein
• Suppressor of Cytokine Signaling Proteins (metabolism)
• Trans-Activators (genetics, metabolism)
• Transfection
• Viral Regulatory and Accessory Proteins