Interferon-free treatment for hepatitis C virus infection induces normalization of extrahepatic type I interferon signaling

BACKGROUND/AIMS: Hepatitis C virus (HCV) replicates in the peripheral blood mononuclear cells (PBMCs), leading to the production of type I interferons (IFNs). It is well known that the gene expression profile of PBMC is similar to that of the liver. The present study explored the dynamic gene expression profile of PBMCs collected from HCV-infected patients undergoing direct-acting antiviral (DAA) therapy. METHODS: A prospective cohort comprising 27 patients under DAA therapy was formed. Expression level of IFN-β and its downstream interferon-stimulated genes (ISGs) was measured in PBMCs before and after DAA treatment. Furthermore, immunoblotting was performed to identify the signaling molecules involved in the expression of ISGs. RESULTS: The pretreatment expression level of interferon-induced protein 44 (IFI44) and C-X-C motif chemokine ligand 10 (CXCL10) correlated with the pretreatment expression level of IFN-β. After DAA treatment, a significant decrease in the expression levels of IFN-β, IFI44, and CXCL10 was observed in the PBMCs. Furthermore, the pretreatment expression level of IFN-β and ISGs correlated with the level of signal transducer and activator of transcription 1 (STAT1) phosphorylation, and DAA treatment abrogated STAT1 phosphorylation. CONCLUSIONS: Pretreatment activation of IFN-β response is rapidly normalized after DAA treatment. The present study suggests that the decreased type I IFN response by the clearance of HCV might contribute to DAA-induced alleviation of extrahepatic manifestation of chronic HCV infection.

Elk-3 Contributes to the Progression of Liver Fibrosis by Regulating the Epithelial-Mesenchymal Transition

BACKGROUND/AIMS: The role of Elk-3 in the epithelial-mesenchymal transition (EMT) during liver fibrogenesis remains unclear. Here, we determined the expression of Elk-3 in in vitro and in vivo models and in human liver fibrotic tissues. We also investigated the molecular relationships among Elk-3, early growth response-1 (Egr-1), and the mitogen activated protein kinases (MAPK) pathway during EMT in hepatocytes. METHODS: We established anin vitro EMT model in which normal mouse hepatocyte cell lines were treated with transforming growth factor (TGF)-β1 and a CCl4-induced liver fibrosis model. Characteristics of EMT were determined by evaluating the expression levels of related markers. The expression of Elk-3 and its target Egr-1 were analyzed using Western blotting. Gene silencing of Elk-3 was performed using an siRNA knockdown system. RESULTS: The expression levels of mesenchymal markers were increased during TGF-β1-induced EMT of hepatocytes. The expression levels of Elk-3 and Egr-1 were significantly (p<0.05) increased during the EMT of hepatocytes, in CCl₄-induced mouse liver fibrotic tissues, and in human liver cirrhotic tissues. Silencing of Elk-3 and inhibition of the Ras-Elk-3 pathway with an inhibitor suppressed the expression of EMT-related markers. Moreover, Elk-3 expression was regulated by p38 MAPK phosphorylation during EMT. CONCLUSIONS: Elk-3 contributes to the progression of liver fibrosis by modulating the EMT via the regulation of Egr-1 under MAPK signaling.

Immunostimulatory Activity of Apios Tuber Extract on RAW264.7 Macrophage Cells

Apios americana Medik tubers are medicinal foods with anti-cancer and anti-inflammatory activities. However, mechanisms of immunostimulatory action of the Apios tuber extract (ATE) on macrophages have not been elucidated. In the present study, we investigated whether ATE could modulate immune responses, such as production of nitric oxide (NO), proinflammatory cytokines, and transcription factors, in RAW264.7 macrophage cells. ATE significantly increased the production of NO and proinflammatory cytokines such as interleukin-1β (IL-1β), IL-6, and tumor necrosis factor-α (TNF-α), and induced the mRNA and protein levels of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2) and proinflammatory cytokines in a dose-dependent manner. Furthermore, Western blot analysis revealed that ATE activated the transcription factor Nuclear Factor-κB and mitogen-activated protein kinases signaling cascades, including extracellular signal-regulated kinase, c-Jun N-terminal kinase, and p38 kinase. In addition, we found that ATE induced the activation of macrophages through upregulation of toll-like receptor 4 (TLR4) and TLR2. Taken together, these findings indicate that ATE possesses a potential as a functional food with immunostimulatory activity.

NDRG2-mediated Modulation of SOCS3 and STAT3 Activity Inhibits IL-10 Production

BACKGROUND: N-myc downstream regulated gene 2 (NDRG2) is a member of the NDRG gene family. Our previous report indicated a possible role for NDRG2 in regulating the cytokine, interleukin-10 (IL-10), which is an important immunosuppressive cytokine. Several pathways, including p38-MAPK, NF-kappaB, and JAK/STAT, are used for IL-10 production, and the JAK/STAT pathway can be inhibited in a negative feedback loop by the inducible protein, SOCS3. In the present study, we investigated the effect of NDRG2 gene expression on IL-10 signaling pathway that is modulated via SOCS3 and STAT3. METHODS: We generated NDRG2-overexpressing U937 cell line (U937-NDRG2) and treated the cells with PMA to investigate the role of NDRG2 in IL-10 production. U937 cells were also transfected with SOCS3- or NDRG2-specific siRNAs to examine whether the knockdown of SOCS3 or NDRG2 influenced IL-10 expression. Lastly, STAT3 and SOCS3 induction was measured to identify the signaling pathway that was associated with IL-10 production. RESULTS: RT-PCR and ELISA assays showed that IL-10 was increased in U937-mock cells upon stimulation with PMA, but IL-10 was inhibited by overexpression NDRG2. After PMA treatment, STAT3 phosphorylation was decreased in a time-dependent manner in U937-mock cells, whereas it was maintained in U937-NDRG2 cells. SOCS3 was markedly reduced in U937-NDRG2 cells compared with U937-mock cells. IL-10 production after PMA stimulation was reduced in U937 cells when SOCS3 was inhibited, but this effect was less severe when NDRG2 was inhibited. CONCLUSION: NDRG2 expression modulates SOCS3 and STAT3 activity, eventually leading to the inhibition of IL-10 production.

The Clinical Characteristics and the Usefulness of the Ocular Compression Test in Syncope of Children Test / 대한소아신경학회지

PURPOSE:Nevertheless that syncope of children is a relatively common disease which occurs during adolescence, diagnostic yield rate of syncope of children is far below than that of adults. Some reports indicate that the diagnostic rate could be increased up to 70% by using the head-up tilt test(HUT). However, HUT is relatively invasive and harmful to be used for children. The purpose of this study is to analyze the etiology of syncope in children and investigate whether the ocular compression test(OCT), which is not invasive and relatively safe, could substitute the HUT for vasovagal syncope. METHODS:Children who visited NHIC Ilsan Hospital for syncope from January 2004 to July 2006 were retrospectively analyzed. We examined the medical records of the patients and performed the basic diagnostic tests including EEG as well as HUT. OCT was performed during EEG to find check out the presence and the duration of asystole. We classified the patients into 3 groups according to the etiology, such as neurally-mediated(vasovagal), cardiovascular and non- cardiovascular syncopes and comparatively analyzed the clinical characteristics of each group. In addition, in case the asystole duration of OCT is prolonged, we performed cross-table analysis to know whether it matches the positive result of HUT in order to confirm the availability of OCT. RESULTS:55 patients were included in the study and the rate of males to female was 1: 2.4. The causes of syncope were identified in 43 cases(78.2%) and half of which was neurally- mediated type. In detail, 24(43.6%) patients were neurally-mediated, 5(9.1%) were cardiovascular, 14(25.5%) non-cardiovascular and 12(21.8%) unidentified. There was no significant difference regarding the clinical characteristics among diagnostic groups. However, the neurally- mediated syncope group showed statistically significant difference in the duration of asystole. Therefore, when we make a point over 3 seconds of asystole in OCT, it will produce the most similar result with the HUT in neurally-mediated(vasovagal) syncope(specificity 94.4%). CONCLUSION:Generally, syncope in children peaks during adolescence and it is more common among girls than boys. The etiologic diagnostic rate was 78.2% and the neurally-mediated syncope was the most common type. The cardiovascular syncope of children was much less in contrast to that of adults. There was no statistically significant difference in the clinical characteristics among the three diagnostic groups. It is concluded that OCT, a non-invasive and relatively safe test, could substitute the invasive, and harmful HUT for vasovagal syncope of children.