PCBP2 enhances the antiviral activity of IFN-α against HCV by stabilizing the mRNA of STAT1 and STAT2.
Interferon-α (IFN-α) is a natural choice for the treatment of hepatitis C, but half of the chronically infected individuals do not achieve sustained clearance of hepatitis C virus (HCV) during treatment with IFN-α alone. The virus can impair IFN-α signaling and cellular factors that have an effect on the viral life cycles. We found that the protein PCBP2 is down-regulated in HCV-replicon containing cells (R1b). However, the effects and mechanisms of PCBP2 on HCV are unclear. To determine the effect of PCBP2 on HCV, overexpression and knockdown of PCBP2 were performed in R1b cells. Interestingly, we found that PCBP2 can facilitate the antiviral activity of IFN-α against HCV, although the RNA level of HCV was unaffected by either the overexpression or absence of PCBP2 in R1b cells. RIP-qRT-PCR and RNA half-life further revealed that PCBP2 stabilizes the mRNA of STAT1 and STAT2 through binding the 3'Untranslated Region (UTR) of these two molecules, which are pivotal for the IFN-α anti-HCV effect. RNA pull-down assay confirmed that there were binding sites located in the C-rich tracts in the 3'UTR of their mRNAs. Stabilization of mRNA by PCBP2 leads to the increased protein expression of STAT1 and STAT2 and a consistent increase of phosphorylated STAT1 and STAT2. These effects, in turn, enhance the antiviral effect of IFN-α. These findings indicate that PCBP2 may play an important role in the IFN-α response against HCV and may benefit the HCV clinical therapy.
National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
Zhongshuai
Z
Xin
Wei
W
Han
Zhiqiang
Z
Zhao
Qing
Q
Xia
Bin
B
Yin
Jiangang
J
Yuan
Xiaozhong
X
Peng
D020413:3' Untranslated Regions / Q000235:genetics; D000998:Antiviral Agents / Q000494:pharmacology*; D001483:Base Sequence; D001665:Binding Sites; D045744:Cell Line, Tumor; D015536:Down-Regulation / Q000187:drug effects; D016679:Genome, Viral / Q000235:genetics; D016174:Hepacivirus / Q000187:drug effects* / Q000235:genetics; D006801:Humans; D016898:Interferon-alpha / Q000494:pharmacology*; D008954:Models, Biological; D008969:Molecular Sequence Data; D011485:Protein Binding / Q000187:drug effects; D020871:RNA Stability / Q000187:drug effects*; D016601:RNA-Binding Proteins / Q000378:metabolism*; D012093:Replicon / Q000235:genetics; D050794:STAT1 Transcription Factor / Q000235:genetics* / Q000378:metabolism; D050795:STAT2 Transcription Factor / Q000235:genetics* / Q000378:metabolism; D015854:Up-Regulation / Q000187:drug effects; D017361:Viral Nonstructural Proteins / Q000378:metabolism; D012324:RNA-Dependent RNA Polymerase
D020413:3' Untranslated Regions; D000998:Antiviral Agents; D016898:Interferon-alpha; D016601:RNA-Binding Proteins; D050794:STAT1 Transcription Factor; D050795:STAT2 Transcription Factor; D017361:Viral Nonstructural Proteins; C093542:NS4 protein, hepatitis C virus; C501903:PCBP2 protein, human; C494079:STAT1 protein, human; C494084:STAT2 protein, human; C087036:NS-5 protein, hepatitis C virus; D012324:RNA-Dependent RNA Polymerase