The influence of HBV and its antigens on the expressions of JAK-STAT signal transduction pathway molecules and antiviral proteins of IFN alpha / 中华肝脏病杂志

<p><b>OBJECTIVE</b>To investigate the possible influence of HBV and its antigens on the expressions of JAK-STAT signal transduction pathway molecules and the antiviral proteins of IFN alpha.</p><p><b>METHODS</b>The HepG2 cells were transfected with pSM2, pHBS2-S and pHBc-EGFP plasmids which express HBV whole particles or S-antigen, Pre-S antigen and core antigens. The infectious supernatant from HepG2.2.15 cells and the pured HBV proteins which contained the S, Pre-S antigens were used to treat the HepG2 cells. Northern blot and RT-PCR were applied to analyse the expressions of the antiviral proteins MxA, 2' -5' OAS, 9-27 and the JAK-STAT signal transduction pathway molecules STAT1 in HepG2 cells responded to the IFN alpha treatment.</p><p><b>RESULTS</b>The HepG2 cells transfected with pSM2, pHBS2-S and pHBc-EGFP plasmids could express whole HBV particles and HBsAg, Pre-S antigen and HBcAg. The quantitation of expressed HBV particles and antigens increased significantly during the course of transfection. Northern blot hybridization analysis indicated that the HepG2 cells expressed IFN alpha antiviral proteins MxA, 2' -5' OAS and 9-27. When transfected with pHBV-dimer, pHBS2-S, pHBc-EGFP plasmids, the IFN/A antiviral proteins MxA, 2' -5' OAS and 9-27 in transfected cells were reduced greatly as compared to the un-transfected HepG2 cells, and the expressed antiviral proteins decreased sharply with the development of transfection time. Furthermore, the expression of IFN alpha JAK-STAT signal transduction pathway molecule STAT1 was also inhibited with the expression of HBV particles and HBV antigens in transfected HepG2 cells.</p><p><b>CONCLUSIONS</b>The HBV and its antigens influence the expressions of IFN alpha JAK-STAT signal transduction pathway molecules and antiviral proteins in the hepatocellular models in vitro. It is indicated that HBV might possess the activity to antagonise or counteract the IFN alpha antiviral action.</p>

Based on the low-density cDNA Macroarray for screening of antiviral proteins of IFNa tissues / 中华肝脏病杂志

<p><b>OBJECTIVE</b>To screen the gene expression profiles of IFN-alpha antiviral proteins based on a low-density cDNA Macroarray, and to explore the relationship between the expression of antiviral protein and the HBV replication.</p><p><b>METHODS</b>The HepG2 and HepG2.2.15 cells were treated with various concentrations of IFN-alpha (0 IU/ml, 100 IU/ml, 1000 IU/ml) of IFN-alpha for 6 h, and then the low-density cDNA Macroarray was used for analysing the expression profiles of antiviral genes and screening differential expressions of antiviral proteins. Meanwhile, the HepG2 cells were transiently transfected with HBV core protein-expressed plasmid pHBc-EGFP, and the expressions of antiviral proteins were analysed by RT-PCR assay. Moreover, the HepG2.2.15 cells were also transfected with the antiviral protein-expressed plasmid pcDNA3.1-Flag-MxA. ELISA was used for analysing the secreted HBV antigens, while dot blot and Southern blot were applied for analysing the extracellular HBV DNA and intracellular replicative intermediate HBV DNA in HepG2.2.15 cells. All data were presented as mean+/-SD and analyzed using the t-test and one-way analysis of variance (ANOVA) in the experiments.</p><p><b>RESULTS</b>The Macroarray results suggested that the expression of IFN-alpha antiviral genes like 6-16, IFITM1, IFITM2, IFITM3 and RING4 in HepG2.2.15 cells were partially inhibited. More importantly, it was found, in this research, the expression of antiviral protein MxA in HepG2.2.15 cells was completely suppressed. RT-PCR analysis indicated that the expression of MxA was also significantly decreased in HepG2 cells transfected with pHBc-EGFP plasmid. Although HepG2.2.15 cells transfected with pcDNA3.1-Flag-MxA plasmid could not inhibit extracellular HBV DNA and intracellular replicative intermediate HBV DNA, the MxA exerted some antiviral activities as it effectively suppressed the secretion of HBsAg and HBeAg in HepG2.2.15 cells.</p><p><b>CONCLUSIONS</b>HBV and its antigen components probably influence the expression of antiviral proteins. IFN- resistance may be related to the down-regulation of antiviral proteins expression.</p>

Significance of novel HBV expression vectors in selecting antiviral drugs in clinical therapy / 中华肝脏病杂志

<p><b>OBJECTIVE</b>To establish a new method for rapidly selecting anti-hepatitis B virus drugs in clinical therapy.</p><p><b>METHODS</b>The full-length hepatitis B virus (HBV) genomes from 8 patients with chronic hepatitis B (CHB) were generated by polymerase chain reaction (PCR). All patients were resistant to lamivudine therapy. Their HBV DNA fragments were inserted into Sap I site of pHY106 eukaryotic expression vector separately. The recombinant plasmids containing 1.1 copies of HBV genome were transfected into Huh7 cell line; the levels of HBsAg, HBeAg and HBV DNA in supernatants of Huh7 cells were measured by ELISA and real-time quantitative PCR, and intracellular HBV replicative intermediates were detected by Southern blot. Antiviral effects of lamivudine and adefovir were evaluated in this vitro system.</p><p><b>RESULTS</b>The 8 recombinant plasmids containing a full-length genome of clinical HBV isolates could replicate and be expressed in Huh 7 cells. There were 6 isolates with polymerase YVDD mutations and 2 isolates with polymerase YIDD mutations. Adefovir, but not lamivudine, inhibited the HBV replication and gene expression in vitro. Furthermore, adefovir inhibited HBV replication in these CHB patients.</p><p><b>CONCLUSION</b>The method described here enables a rapid selection of anti-HBV drugs in clinical therapy and is very useful in antiviral therapy for CHB patients.</p>

Construction and Characterization of a Hepatitis B Virus Replicon / 中国病毒学

To establish a replication cellular model of hepatitis B virus (HBV) and determine its application in antiviral drug evaluation,we constructed an expression plasmid which contained 1.3 copies of the HBV genome,and measured the level of viral replication after transient transfection in Huh7 cells.We then observed the effect of antiviral drug administration.1.3 fold of the HBV(ayw) gene fragment was cloned into pCR2.1 by PCR and restriction endonuclease digestion.The recombinant plasmid was trans ient transfected into Huh7 cells,HBsAg,HBeAg and HBV DNA in supernatant of Huh7 cells were measured by ELISA and real-time PCR respectively; intracellular HBV replicative intermediates and intracellular HBV transcripts were detected by Southern blot and Northern blot respectively.The antiviral effect of adefovir,a novel anti-HBV nucleotide analogue,was evaluated in this cellular model system.The results indicated that a recombinant plasmid of HBV replicon was constructed successfully; the HBV genome carried in plasmid pHBV1.3 could efficiently replicate and be expressed in Huh 7 cells,adefovir could inhibit HBV replication in this cellular model,and the inhibition was dosage-dependent.The conclusion is HBV replicon,which can initiate viral replication efficiently in hepatoma cells,may be a useful tool in the study of HBV replication and antiviral drug.

Antiviral Effect of Interferon-Induced Guanylate Binding Protein-1 against Coxsackie Virus and Hepatitis B Virus B3 in Vitro / 中国病毒学

Guanylate binding protein-1(GBP-1) is an interferon-induced protein. To observe its antiviral effect against Hepatitis B virus (HBV) and Coxsackie virus B3 (CVB3), we constructed an eukaryotic expression vector of human GBP-1(hGBP-1). Full-length encoding sequence of hGBP-1 was amplified by long chain RT-PCR and inserted into a pCR2.1 vector, then subcloned into a pCDNA3.1(-) vector. Recombinant hGBP-1 plasmids and pHBV1.3 carrying 1.3-fold genome of HBV were contransfected into HepG2 cells, and inhibition effect of hGBP-1 against HBV replication was observed. Hela cells transfected with recombinant hGBP-1 plasmids were challenged with CVB3, and viral yield in cultures were detected. The results indicated that recombinant eukaryotic expression plasmid of hGBP-1 was constructed successfully and the hGBP-1 gene carried in this plasmid could be efficiently expressed in HepG2 cells and Hela cells. hGBP-1 inhibit CVB3 but not HBV replication in vitro. These results demonstrate that hGBP-1 mediates an antiviral effect against CVB3 but not HBV and perhaps plays an important role in the interferon-mediated antiviral response against CVB3.

Establishment of a new low-density cDNA macroarray and the application in the activity of IFN against HBV / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To investigate the expression profile of genes which are involved in IFN antiviral activity and IFN signal transduction pathway in Hep G2 and HepG2.2.15 cells.</p><p><b>METHODS</b>Genes of interest were selected from the UniGene database (http://www.ncbi.nlm.gov/UniGene/Hs.Home.html). The 5'IMAGE clones with 0.5-0.8 kb length were chosen and ordered from RZPD company. The cDNA inserts were amplified by PCR and then were spotted onto the Hybond-N+ membranes. The membranes were denatured and neutralized for Macroarray analysis. HepG2.2.15 and Hep G2 cells were treated without or with IFN-alpha for 6 h, and the total cellular RNA was isolated using Trizol Reagent. Radio-labelled cDNA was generated from 20 microgram of RNA by reverse transcription using 360 units of reverse transcriptase in the presence of 30 microCi of alpha-32P dCTP. Hybridization was performed between 32P-labelled cDNA and membrane arrays. The membranes were then scanned, and the intensity of autoradiographic spots was quantitated by Cyclone Storage Phosphor System. The images were subsequently analysed by the OptiQuant Imager Analysis Software and converted into digital data.</p><p><b>RESULTS</b>The authors found that just partially IFN-inducible genes were expressed in Hep G2 and HepG2.2.15 cells, and the majority of IFN-inducible genes was lowly responsive or non-responsive to IFN-a treatment. Some interferon-stimulated genes (ISGs) were inhibited or blocked, especially in HepG2.2.15 cells. Interestingly, the authors found that the IFN signal transduction pathway (Jak-STAT) was intact and unimpaired in HepG2.2.15 cells.</p><p><b>CONCLUSION</b>Differential gene expression profiles in response to IFN were found between Hep G2 and HepG2.2.15 cells.</p>