The Role Of PCBP2in Type Ⅰ Intefreron Induced By Virus In Human Hepatocytes

PCBP2(poly(rC) binding protein2) is one member of the family ofheterogeneous nuclear ribonucleoproteins(hnRNPs). It belongs to a class of proteinsthat bind to poly(C) stretches of both RNA and DNA.lt plays an important role incellular physiological processes, apart from its roles in maintaining mRNA stabilityand regulating translation, PCBP2also can participate in protein-protein interactionsand bind to microRNA.PCBP2is a cellular cytokine secreted by host cells. In recentyears, the researchs about the interactions between PCBP2and virus become moreand more,it discovered that PCBP2can participate in varieties of viral RNAreplication process, what is more,it is involved in cellular immune response.lt havebeen reported that PCBP2have an impact on viral RNA replication in HCV andNDV,but its functions in virus-infected human hepatocytes to producingtype I interferon have not been reported.Here we explored the role of PCBP2in induction of type I interferon by virus inhuman hepatocytes. First, shRNA targeted PCBP2was designed and cloned into thenovel pSilencer vector. The construct was transfected into human hepatocyteHLCZOl.We successfully get the stable cell lines that have60%-90%gene silencingeffect on PCBP2. Then we used a double-stranded RNA poly(I:C) which issynthesized in vitro to simulate the stable cell lines. The data showed that kockdownof PCBP2enhanced the expression of IFNβ mRNA level in response to poly(I:C)stimulation. Kockdown of PCBP2in HLCZ01cells reduced the level of NDV，significantly increased the expression of IFNp and interferon-stimulated genesISG12a，ISG56，ISG60and G1P3in response to NDV infection. We infected HLCZ01cells with HCV which is single strand RNA virus, as we guessed. We found thatkockdown of PCBP2significantly inhibited HCV RNA replication, but also increasedthe induction of IFNp and interferon-stimulated genes ISG12a, ISG56，ISG60andG1P3by HCV infection. In short, silenced PCBP2can down-regulated the RNAreplication and enhanced the expression of IFNβ and interferon-stimulated genes inresponse to viral infection, indicating that PCBP2is a negative factor in IFN signalingpathway.There are about170million people who were infected with HCV, but there areshort of effective treatment for HCV in clinical. It is urgent to develop new effective drugs for anti-HCV. Anti-cancer therapy research with the target gene PCBP2has juststarted.Our data suggested that PCBP2has a negative impact on IFN signalingpathway. PCBP2may be used as a target to develop new drugs for the treatment ofHCV. We hope that this can provide a new vision on the herapeutic method of viraldiseases.