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Inhibitory effect of a triterpenoid compound, with or without alpha interferon, on hepatitis C virus infection.

ABSTRACT: A lack of patient response to alpha interferon (?-IFN) plus ribavirin (RBV) treatment is a major problem in eliminating hepatitis C virus (HCV). We screened chemical libraries for compounds that enhanced cellular responses to ?-IFN and identified a triterpenoid, toosendanin (TSN). Here, we studied the effects and mechanisms of action of TSN on HCV replication and its effect on ?-IFN signaling. We treated HCV genotype 1b replicon-expressing cells and HCV-J6/JFH-infected cells with TSN, with or without ?-IFN, and the level of HCV replication was quantified. To study the effects of TSN on ?-IFN signaling, we detected components of the interferon-stimulated gene factor 3 (ISGF3), phosphorylated signal transducer and activator of transcription 1 (STAT1), and STAT2 by Western blotting analysis; expression levels of mRNA of interferon regulatory factor 9 using real-time reverse transcription-PCR (RT-PCR); and interferon-stimulated response element reporter activity and measured the expression levels of interferon-inducible genes for 2',5'-oligoadenylate synthetase, MxA, protein kinase R, and p56 using real-time RT-PCR. TSN alone specifically inhibited expression of the HCV replicon (50% effective concentration = 20.6 nM, 50% cytotoxic concentration > 3 ?M, selectivity index > 146). Pretreatment with TSN prior to ?-IFN treatment was more effective in suppressing HCV replication than treatment with either drug alone. Although TSN alone did not activate the ?-IFN pathway, it significantly enhanced the ?-IFN-induced increase of phosphorylated STATs, interferon-stimulated response element activation, and interferon-stimulated gene expression. TSN significantly increased baseline expression of interferon regulatory factor 9, a component of interferon-stimulated gene factor 3. Antiviral effects of treatment with ?-IFN can be enhanced by pretreatment with TSN. Its mechanisms of action could potentially be important to identify novel molecular targets to treat HCV infection.

SUBMITTER: Watanabe T

PROVIDER: S-EPMC3101404 | biostudies-literature | 2011 Jun

REPOSITORIES: biostudies-literature

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Inhibitory effect of a triterpenoid compound, with or without alpha interferon, on hepatitis C virus infection.

Watanabe Takako T Sakamoto Naoya N Nakagawa Mina M Kakinuma Sei S Itsui Yasuhiro Y Nishimura-Sakurai Yuki Y Ueyama Mayumi M Funaoka Yusuke Y Kitazume Akiko A Nitta Sayuri S Kiyohashi Kei K Murakawa Miyako M Azuma Seishin S Tsuchiya Kiichiro K Oooka Shinya S Watanabe Mamoru M

Antimicrobial agents and chemotherapy 20110328 6

A lack of patient response to alpha interferon (α-IFN) plus ribavirin (RBV) treatment is a major problem in eliminating hepatitis C virus (HCV). We screened chemical libraries for compounds that enhanced cellular responses to α-IFN and identified a triterpenoid, toosendanin (TSN). Here, we studied the effects and mechanisms of action of TSN on HCV replication and its effect on α-IFN signaling. We treated HCV genotype 1b replicon-expressing cells and HCV-J6/JFH-infected cells with TSN, with or wi ...[more]

PMID: 21444704

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Project description:AimTo investigate the association between interferon-induced protein with tetratricopeptide repeats 1 (IFIT1) polymorphisms and interferon-α (IFNα) treatment efficiency among Chinese hepatitis B virus (HBV) infection patients.MethodsTwo hundred and twenty five newly diagnosed chronic hepatitis B (CHB) patients were enrolled in the study. All of these patients received IFNα treatment for a course of 48 wk, and were followed up for 24 wk after the treatment was end. Clinical information about virological response, hepatitis B e antigen (HBeAg) seroconversion rate and combined response at the end of the treatment, as well as the sustained response by the time of following up 24 wk after the treatment, was collected. Four tag-single nucleotide polymorphisms (SNPs) of IFIT1 were selected and assessed for their association with these clinical outcomes.ResultsAt the end of the treatment, HBeAg seroconversion was observed in 27.1% patients. Thirty-six point nine percent patients achieved virological response, and 15.6% patients exhibited combined response. Sustained response was obtained in 26.2% patients. The main HBV genotype of the study was genotype B. Patients who infected with HBV genotype B or C showed better treatment efficiency, no matter which clinical outcome was considered. Among the four SNPs assessed, rs303218 (A > G) was found to be significantly associated with the end point virological response when assuming additive model [OR = 0.64 (95%CI: 0.42-0.96), P = 0.032]. Patients who carried rs303218 GG genotype had a rather higher rate of achieving virological response (response rate: 52%, OR = 0.40, 95%CI: 0.18-0.91; P = 0.028) when compared to those had AA genotype (response rate: 27%). The most significant interaction was observed in patients who had relative lower baseline aspartate transaminase. No association between SNPs and HBeAg seroconversion, combined response or sustained response was observed.ConclusionIFIT1 involves in the regulation of IFNα treatment for CHB and its polymorphism rs303218 can predict the end point virological response. The finding requires further validation.

Project description:Long noncoding RNAs (lncRNAs) play a critical role in the regulation of many important cellular processes. However, the mechanisms by which lncRNAs regulate viral infection and host immune responses are not well understood. We sought to explore lncRNA regulation of hepatitis C virus (HCV) infection and interferon response. We performed RNA sequencing (RNAseq) in Huh7.5.1 cells with or without interferon alpha (IFN?) treatment. Clustered regularly interspaced short palindromic repeats/Cas9 guide RNA (gRNA) was used to knock out selected genes. The promoter clones were constructed, and the activity of related interferon-stimulated genes (ISGs) were detected by the secrete-pair dual luminescence assay. We constructed the full-length and four deletion mutants of an interferon-induced lncRNA RP11-288L9.4 (lncRNA-IFI6) based on predicted secondary structure. Selected gene mRNAs and their proteins, together with HCV infection, in Huh7.5.1 cells and primary human hepatocytes (PHHs) were monitored by quantitative real-time PCR (qRT-PCR) and western blot. We obtained 7,901 lncRNAs from RNAseq. A total of 1,062 host-encoded lncRNAs were significantly differentially regulated by IFN? treatment. We found that lncRNA-IFI6 gRNA significantly inhibited HCV infection compared with negative gRNA control. The expression of the antiviral ISG IFI6 was significantly increased following lncRNA-IFI6 gRNA editing compared with negative gRNA control in Japanese fulminant hepatitis 1 (JFH1)-infected Huh7.5.1 cells and PHHs. We observed that lncRNA-IFI6 regulation of HCV was independent of Janus kinase-signal transducer and activator of transcription (JAK-STAT) signaling. lncRNA-IFI6 negatively regulated IFI6 promoter function through histone modification. Overexpression of the truncated spatial domain or full-length lncRNA-IFI6 inhibited IFI6 expression and increased HCV replication. Conclusion: A lncRNA, lncRNA-IFI6, regulates antiviral innate immunity in the JFH1 HCV infection model. lncRNA-IFI6 regulates HCV infection independently of the JAK-STAT pathway. lncRNA-IFI6 exerts its regulatory function via promoter activation and histone modification of IFI6 through its spatial domain.

Dataset Information

Inhibitory effect of a triterpenoid compound, with or without alpha interferon, on hepatitis C virus infection.

Publications

Inhibitory effect of a triterpenoid compound, with or without alpha interferon, on hepatitis C virus infection.

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