OBJECTIVETo study the inhibition effect of HCV NS5A on p53 protein transactivity and its possible mechanism.

METHODSLuciferase reporter gene system was used for the study of p53 transactivity on p21 promoter and electrophorectic mobility-shift assay (EMSA) was applied to observe whether HCV NS5A could suppress the binding ability of p53 protein to its specific DNA sequence.

RESULTSEndogenous p53 protein could stimulate p21 promoter activity, and the relative luciferase activity increased significantly (3.49 x 10(5) vs 0.60 x 10(5), t = 5.92, P<0.01). Exogenous p53 protein also up-regulated p21 promoter driving luciferase expression, comparing to the control group (0.47 x 10(5)), the relative luciferase activity increased (5.63 x 10(5)) obviously (t = 10.12, P<0.01). HCV NS5A protein inhibited both endogenous and exogenous p53 transactivity on p21 promoter in a dose-dependent manner (F > or = 20.71, P<0.01). In the experiment of EMSA, p53 could bind to its specific DNA sequence, but when co-transfected with HCV NS5A expressing vector, the p53 binding affinity to its DNA decreased.

CONCLUSIONHCV NS5A can inhibit p53 protein transactivity on p21 promoter through its inhibiting of p53 binding ability to the specific DNA sequence.

Hepacivirus ; genetics ; Humans ; Promoter Regions, Genetic ; Transcriptional Activation ; drug effects ; Tumor Suppressor Protein p53 ; drug effects ; genetics ; metabolism ; physiology ; Viral Core Proteins ; genetics ; Viral Nonstructural Proteins ; genetics ; pharmacology

OBJECTIVETo investigate the influence of miR-122 on IFN-α treatment for HCV infection.

METHODSHuh7.5.1 cells infected with HCV were treated with miR-122 mimics (20 nmol/L, 100 nmol/L, 400 nmol/L) and/or IFN-α (1000 IU/ml). The relative expression of HCV RNA was detected by real-time polymerase chain reaction (PCR). Huh7.5.1 cells were treated with different amounts of HCV (107 copies, 106 copies and 105 copies) and/or IFN-α (1000 IU/ml).

RESULTSIFN-α suppressed the replication of HCV in a time-dependent manner, resulting in a ≊ 83% reduction of HCV at 48 h. MiR-122 mimics facilitated replication of HCV RNA in a dose-dependent manner (P<0.05). The antiviral effect of IFN-α was inverted to levels of miR-122 mimics (20 nmol/L, 100 nmol/L, 400 nmol/L), (73.3% ± 3.5% compared with 84% ± 4.5%, P>0.05; 64.67% ± 5.5% compared with 84% ± 4.5%, P>0.05; 56.33% ± 5.1% compared with 84% ± 4.5%, P<0.05). The antiviral effect of IFN-α was inverted to HCV load (105 copies group compared with 107 copies group, P<0.05).

CONCLUSIONMiR-122 facilitates replication of HCV RNA in the cell culture system; and the expression of miR-122 may partly counteract the anti-HCV effect of IFN-α.

Antiviral Agents ; pharmacology ; Cell Line, Tumor ; Hepacivirus ; drug effects ; genetics ; physiology ; Humans ; Interferon-alpha ; pharmacology ; MicroRNAs ; genetics ; RNA, Viral ; genetics ; Transfection ; Virus Replication ; drug effects ; genetics

OBJECTIVETo investigate the impact of interferon-stimulated exonuclease 20 kDa (ISG20) on replication of genotype 2a hepatitis C virus (HCV) subgenomic replicon RNA and infectivity of the cell culture-derived HCV strain JFH1 to determine the potential of exogenously expressed ISG20 as an anti-viral therapy of chronic hepatitis C.

METHODSPlasma vectors containing wild-type (WT) ISG20 or a catalytically-inactive mutant ISG20m were transiently transfected into Huh7, Huh7.5 and HEK293 cells, and the replication of a monocistronic subgenomic JFH1 RNA replicon, SGRm-JFH1BlaRL, was measured. Huh7.5 cells stably expressing ISG20, ISG20m, or the control vector were established by transducing replication incompetent pCX4-Bsr-myc retroviruses encoding WT ISG20, D94G mutant ISG20, or the empty vector, respectively, and selecting with 5 mug/mL of blasticidin for approximately three weeks. The stable Huh7.5 cells were then transfected with HCV replicon RNA and infected with cell culture-derived HCV to investigate inhibition capacity of ISG20 against HCV.

RESULTSHuh7.5-ISG20, Huh7.5-ISG20m, and Huh7.5-Bsr controls cells stably expressing ISG20, ISG20m, or the control vector, respectively, were constructed successfully; the ectopically expressed ISG20 and ISG20m were distributed in both nucleus and cytoplasm, as detected by immuno uorescence. SGRm-JFH1BlaRL replicated efficiently and with similar kinetics in the Huh7.5-Bsr and Huh7.5-ISG20m cells, with expression levels plateauing at 48-96 h post-transfection. In contrast, at all time points examined, SGRm-JFH1BlaRL replication was 9.1% to 16.7% in the Huh7.5-ISG20 cells. The Huh7, Huh7.5 and HEK293 cells transiently expressing ISG20 also showed 16.7% to 25.0% of HCV replication that the respective controls. In addition, the amount of infectious progeny JFH1 virus released in culture supernatants was 9.1% to 12.5% from the Huh7.5-ISG20 cells than from the Huh7.5-Bsr and Huh7.5-ISG20m cells at 48-72 h post-infection, and the latter two cultures produced similar JFH1 virus yields. Finally, the expression of HCV core protein was also lower in the Huh7.5-ISG20 cells, as detected by immunoblot analysis.

CONCLUSIONExogenous expression of ISG20, either in a transient or stable manner, suppresses not only replication of genotype 2a HCV RNA replicons but also JFH1 virus propagation in cultured hepatocytes. The exonuclease activity of ISG20 is required for its antiviral activities against HCV.

Antiviral Agents ; pharmacology ; Cell Line ; Genome, Viral ; HEK293 Cells ; Hepacivirus ; genetics ; Humans ; RNA, Viral ; genetics ; Replicon ; Virus Replication ; drug effects

Hepatitis c virus (HCV) infection has become one of the global public health problem,while there is no vaccine to prevent HCV infection, the so-called "cocktail" therapy that use a combination of drugs targeting multiple steps in the HCV infection cycle could achieve better curative effect. the process of HCV entering into host cell is the important step of drug intervention, in which HCV envelope protein El and E2, Host cell factors including Heparan sulfate(HS), CD81, scavenger receptor class B type I (SR-BI), Occludin (OCLD), Claudin (CLDN), low densitity lipoprotein receptor (LDLR), dendritic cell-specific ICAM-3-grabbing nonintegrin (DC-SIGN), Liver/lymph node specific ICAM-3-grabbing integrin(L-SIGN), trans- ferrin receptor 1 (TfR1) and so on play a important role. The virus and the host factors can be used as targets of hcv entry inhibitors many studies have shown that as novel and promising compounds, HCV entry inhibitors combinating with other drugs can be more effective in the treatment of HCV, this paper have re- viewed targets and inhibitors of HCV enterring into host cell since 1990s.
Animals ; Antiviral Agents ; pharmacology ; Hepacivirus ; drug effects ; physiology ; Hepatitis C ; genetics ; metabolism ; virology ; Humans ; Receptors, Virus ; genetics ; metabolism ; Viral Envelope Proteins ; genetics ; metabolism ; Virus Internalization ; drug effects

OBJECTIVETo investigate the inhibitive effects of small interfering RNA (siRNA) on hepatitis C virus (HCV) replication in cells infected by HCV in vitro.

METHODSThe HCV RNA transcripts prepared by pFL-JC1 were transfected into Huh-7.5.1 cells. Na ve Huh-7.5.1 cells were incubated with the supernatants of transfected cells and the expression of HCV core protein in infected cells was detected by indirect immunofluorescence. The infected cells were transfected with 4, 40 and 200 nmol/L of NS5B siRNA for 24 h, 48 h and 72 h, respectively. The normal Huh-7.5.1 cells were transfected with 4, 40 and 200 nmol/L of NS5B siRNA. Group of blank, lipofectamine 2000, unrelated siRNA and IFNα-2b (1000 IU/ml) served as controls. The HCV RNA and PKR mRNA levels were examined by quantitative RT-PCR.

RESULTSThe HCV core protein in HCV infected cells was detected. Compared with control groups, the HCV RNA levels in infected cells significantly decreased when transfected with 40 and 200 nmol/L of siRNA for 24 h; 4, 40 and 200 nmol/L of siRNA for 48 h and 72 h (P<0.05). The HCV RNA levels in infected cells treated with IFNα-2b (1000 IU/ml) for 24 h, 48 h and 72 h were significantly lower than those in control groups (P<0.05 or P<0.01). The PKR mRNA levels in Huh-7.5.1 cells transfected with siRNA of three concentrations did not have significant difference, as compared with control groups (P>0.05).

CONCLUSIONsiRNA against HCV NS5B region can effectively inhibit HCV replication in HCV infected cells, but can not activate the dsRNA-dependent protein kinase (PKR).

Cell Line, Tumor ; Hepacivirus ; drug effects ; genetics ; physiology ; Humans ; RNA, Small Interfering ; pharmacology ; Transfection ; Viral Nonstructural Proteins ; genetics ; Virus Replication ; drug effects

Adult ; Blood Donors ; Hepacivirus ; drug effects ; genetics ; Hepatitis C, Chronic ; virology ; Humans ; Interferons ; pharmacology ; Middle Aged ; Viral Load

Antiviral Agents ; administration & dosage ; Drug Therapy, Combination ; Hepacivirus ; drug effects ; genetics ; Hepatitis C, Chronic ; drug therapy ; Humans ; Interferon-alpha ; administration & dosage ; adverse effects ; Ribavirin ; administration & dosage ; Treatment Outcome

OBJECTIVETo determine the prevalence of mutations in the non-structural protein 5B (NS5B) of the hepatitis C virus (HCV),which are associated with natural resistance to non-nucleoside and nucleoside polymerase inhibitors (PIs),in treatment-naive hepatitis C patients in south China.

METHODSA nested PCR protocol that amplified three different regions of NS5B was used to detect the naturally occurring drag-resistant substitutions.Direct PCR sequencing was performed to analyze the sequences.

RESULTSNS5B mutations known to confer resistance to nucleoside PIs,such as A15G,S96T and S282T,were mainly detected in HCV genotype 6a (20/88,22.73%).Of the NS5B mutations known to confer resistance to non-nucleoside PIs,C316N and S365A were detected in HCV genotype lb (60/60,100% and 2/60,3.33%, respectively) and I482L and V499A were mainly detected in HCV genotype 2a (9/9,100% and 4/4,100%, respectively) and HCV genotype 6a (9/9,100% and 4/4,100%, respectively).Other NS5B mutations found in the study population included A1 5S,S365F,S365P,S368A and S368L;although none of these has been previously shown to confer resistance to PIs.

CONCLUSIONNaturally occurring dominant PI resistance mutations in NS5B exist in treatment-na(i)ve hepatitis C patients in south China and may be related to the virus genotype.

Antiviral Agents ; pharmacology ; China ; Drug Resistance, Viral ; Genotype ; Hepacivirus ; drug effects ; genetics ; Hepatitis C ; drug therapy ; virology ; Humans ; Mutation ; Viral Nonstructural Proteins ; genetics

OBJECTIVETo screen the mi-RNA expression profile after interferon treatment in cells infected with hepatitis C virus (HCV).

METHODSHuh-7.5.1 cells was infected with HCV by in vitro transcription and cultured with interferon. The mi-RNA microarray was used to measure the mi-RNA expression in the control group, HCV transcription group and interference group. Intra-group differences were analyzed by the 2 ((-delt delt CT)) method.

RESULTSWith mi-RNA expressed in normal Huh-7.5.1 cells as a benchmark, expressions of 13 kinds of mi-RNAs were up-regulated after HCV infection and then down-regulated following interferon treatment; 7 were down-regulated after HCV infection and then up-regulated following interferon treatment.

CONCLUSIONmi-RNA10a, mi-RNA21, mi-RNA149, mi-RNA152 and mi-RNA210 may be related to hepatitis C virus replication and transcription.

Cell Line, Tumor ; Gene Expression Profiling ; Hepacivirus ; genetics ; Humans ; Interferon-alpha ; pharmacology ; Interferons ; pharmacology ; MicroRNAs ; drug effects ; genetics ; RNA, Viral ; genetics ; Transfection

OBJECTIVEIt is well known that cyclosporine A (CsA), a widely used immunosuppressant for clinical organ transplantation, has the ability to inhibit HCV replication. In this study, the effects of several other immunosuppressants, including mycophenolic acid (MPA), rapamycin and FK-506, on HCV replication were examined in human hepatocytes.

METHODSHCV JFH-l-infected hepatocytes were treated with immunosuppressants or with control vehicles. The levels of viral RNA and the expression of HCV core protein were determined by quantitative real-time RT-PCR and Western Blot assay, respectively.

RESULTSMPA-treated cells showed significant decreases in both viral RNA and HCV Core protein expression compared with the control cells. Moreover, MPA treatments of hepatocytes before, during or after HCV infection could significantly inhibit viral replication. In contrast, rapamycin and FK-506 had little effect on HCV replication. Mechanism research disclosed that the inhibition of HCV replication by MPA was mainly due to its depletion of guanosine, a purine nucleoside crucial for synthesis of guanosine triphosphate (GTP), which is required for initiation of HCV RNA replication. The supplement of exogenous guanosine could reverse most of anti-HCV effect of MPA.

CONCLUSIONThese results indicate that MPA, through the depletion of guanosine, inhibits HCV JFH-1 replication in hepatocytes, suggesting that MPA may be beneficial for HCV-infected transplant recipients.

Cell Line, Tumor ; Hepacivirus ; drug effects ; genetics ; physiology ; Hepatitis C ; drug therapy ; virology ; Hepatocytes ; virology ; Humans ; Immunosuppressive Agents ; pharmacology ; Mycophenolic Acid ; pharmacology ; RNA, Viral ; genetics ; Virus Replication ; drug effects ; genetics