• Molecules and Cells
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• v.28 no.1
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• pp.49-55
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• 2009

Hepatitis delta virus (HDV) infection causes fulminant hepatitis and liver cirrhosis. To elucidate the molecular mechanism of HDV pathogenesis, we examined the effects of HDV viral proteins, the small hepatitis delta antigen (SHDAg) and the large hepatitis delta antigen (LHDAg), on $NF-{\kappa}B$ signaling pathway. In this study, we demonstrated that $TNF-{\alpha}-induced$ $NF-{\kappa}B$ transcriptional activation was increased by LHDAg but not by SHDAg in both HEK293 and Huh7 cells. Furthermore, LHDAg promoted TRAF2-induced $NF-{\kappa}B$ activation. Using coimmunoprecipitation assays, we demonstrated that both SHDAg and LHDAg interacted with TRAF2 protein. We showed that isoprenylation of LHDAg was not required for the increase of $NF-{\kappa}B$ activity. We further showed that only LHDAg but not SHDAg increased the $TNF-{\alpha}-mediated$ nuclear translocation of p65. This was accomplished by activation of $I{\kappa}B_{\alpha}$ degradation by LHDAg. Finally, we demonstrated that LHDAg augmented the COX-2 expression level in Huh7 cells. These data suggest that LHDAg modulates $NF-{\kappa}B$ signaling pathway and may contribute to HDV pathogenesis.

• Korean Journal of Veterinary Research
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• v.32 no.4
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• pp.605-608
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• 1992

This paper dealt with the clinical and pathological observations on the experimental rabbit viral hepatitis. Rabbits with 2-14 months of ages were intramuscularly inoculated with virus suspension. The results were summarized as follows. Ninety percents of experimental rabbits inoculated with virus died within 96 hours postinoculation. Common clinical signs were inappetence, increase in body temperature, depression, mild diarrhea and in three cases, bloody foam from nostrils was recognized. At necropsy, in most of the experimental cases, there were hyperemia or haemorrhages in many organs and pale liver. Intestinal catarrh and retention of turbid urine in urinary bladder were seen in some cases. Histopathologically, liver necrosis was found in all the cases died of this disease. However, there was a difference in the severity of hepatic necrosis. Haemorrhages were Iecognized in lungs, heart, liver, spleen, kidneys and thymus, in order. Liver necrosis was marked even in the cases with no haemorrhage. Perivascular cuffing in brain and catarrhal enteritis in small intestine were seen in many cases. From these results, consistent and primary lesion in this viral disease is hepatitis in susceptible rabbits. It was concluded that rabbit hepatitis virus might have the properties of hepatotropism and consequently induce peripheral necrosis in the liver leading to acute viremia with haemorrhages.

• Journal of Microbiology and Biotechnology
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• v.24 no.12
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• pp.1744-1754
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• 2014

The hepatitis C virus (HCV) RNA genome is replicated by an RNA replicase complex (RC) consisting of cellular proteins and viral nonstructural (NS) proteins, including NS5B, an RNA-dependent RNA polymerase (RdRp) and key enzyme for viral RNA genome replication. The HCV RC is known to be associated with an intracellular membrane structure, but the cellular components of the RC and their roles in the formation of the HCV RC have not been well characterized. In this study, we took a proteomic approach to identify stomatin, a member of the integral proteins of lipid rafts, as a cellular protein interacting with HCV NS5B. Co-immunoprecipitation and co-localization studies confirmed the interaction between stomatin and NS5B. We demonstrated that the subcellular fraction containing viral NS proteins and stomatin displays RdRp activity. Membrane flotation assays with the HCV genome replication-competent subcellular fraction revealed that the HCV RdRp and stomatin are associated with the lipid raft-like domain of membranous structures. Stomatin silencing by RNA interference led to the release of NS5B from the detergent-resistant membrane, thereby inhibiting HCV replication in both HCV subgenomic replicon-harboring cells and HCV-infected cells. Our results identify stomatin as a cellular protein that plays a role in the formation of an enzymatically active HCV RC on a detergent-resistant membrane structure.

• Bulletin of the Korean Chemical Society
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• v.26 no.2
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• pp.285-291
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• 2005

The nonstructural protein 5B (NS5B) of hepatitis C virus (HCV) is the viral RNA-dependent RNA polymerase (RdRp), which is the essential catalytic enzyme for the viral replication and is an appealing target for the development of new therapeutic agents against HCV infection. A small amount of serum from a single patient with hepatitis C was used to get the genome of a Korean HCV isolate. Sequence analysis of NS5B 1701 nucleotides showed the genotype of a Korean isolate to be subtype 1b. The soluble recombinant HCV NS5B polymerase lacking the C-terminal 24 amino acids was expressed and purified to homogeneity. With the highly purified NS5B protein, we established in vitro systems for RdRp activity to identify potential polymerase inhibitors. The rhodanine family compounds were found to be potent and specific inhibitors of NS5B from high throughput screening (HTS) assay utilizing the scintillation proximity assay (SPA) system. The binding mode of an inhibitor was analyzed by measuring various kinetic parameters. Lineweaver-Burk plots of the inhibitor suggested it binds not to the active site of NS5B polymerase, but to an allosteric site of the enzyme. The activity of NS5B in in vitro polymerase reactions with homopolymeric RNA requires interaction with multiple substrates that include a template/primer and ribonucleotide triphosphate. Steady-state kinetic parameter, such as Km, was determined for the ribonucleotide triphosphate. One of compounds found interacts directly with the viral polymerase and inhibits RNA synthesis in a manner noncompetitively with respect to UTP. Furthermore, we also investigated the ability of the compound to inhibit NS5B-directed viral RNA replication using the Huh7 cell-based HCV replicon system. The investigation is potentially very useful for the utility of such compounds as anti-hepatitic agents.

• Journal of Microbiology and Biotechnology
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• v.14 no.1
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• pp.140-147
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• 2004

Urokinase is an enzyme with fibrinolytic activity (plasminogen activator) isolated from fresh urine of healthy men. Viral safety is an important prerequisite for clinical preparation of the protein from urine. In order to increase the viral safety of a high purity urokinase in regard to non-enveloped viruses, a virus removal process using a novel polyvinylidene fluoride membrane filter (Viresolve NFP) has been optimized. Urokinase was able to pass through the filter with recoveries of 95% in the production scale process. No substantial changes were observed in physical and biochemical characteristics of the filtered urokinase in comparison with those of the enzyme before filtration. A 47-mm disk membrane filter was used to simulate the process performance of the production scale cartridges and tested if it could remove several experimental model viruses for human pathogenic viruses, including porcine parvovirus (PPV), human hepatitis A virus (HAV), murine encephalomyocarditis virus (EMCV), bovine viral diarrhoea virus (BVDV), and bovine herpes virus (BHV). Non-enveloped viruses (PPV, HAV, and EMCV) as well as enveloped viruses (BVDV and BHV) were completely removed during filtration. The log reduction factors achieved were $\geq$4.86 for PPV, $\geq$4.60 for HAV, $\geq$6.87 for EMCV, $\geq$4.60 for BVDV, and $\geq$5.44 for BHV. These results indicate that the virus filtration process successfully improved the viral safety of the final products.

• Journal of Life Science
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• v.5 no.3
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• pp.145-150
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• 1995

Alcoholic liver disease is defined by the development of three types of liver damage following chronic heavy alcohol consumption, namely, alcoholic fatty liver, alcoholic hepatitis, and alcoholic cirrhosis, The clinical features and laboratory tests often do not distinguish among these types of liver injuries. In addition, a considerable number of the patients who have clinical and laboratory features compatible with alcoholic liver disease are diagnosed on liver biopsy to have chronic viral hepatitis or other lesion. Because of these factors, liver biopsy is frequently needed to arrive a definite diagnosis of the disease, its activity, and its chronicity. Fatty liver is usually a benign and reverible condition that disappears on abstinence from alcohol. However, alcoholic hepatitis is usually regarded as a precursor of cirrhosis. The principle factors in the development of alcoholic hepatitis and cirrhosis are the quantity and length of ingestion of alcohol. women are much more susceptible than men to hepatic injuries. Since only 10 - 20% of alcoholics develop cirrhosis, however, it is conceivable that other factors, either genetic, environmental, or nutritional may contribute in the genesis of liver injuries. The most important factor in the treatment of alcoholic liver disease is prolonzed abstinence from alcohol, since abstinence by itself improves clinical status and survival, Nutritional support in patients with nutritional deficiency, and specific drug therapies such as corticosteroid or anabolic steroids for hospitaliged patients with severe alcoholic hepatitis also play an important role in devreasing morbidity and improving survival. Liver transplantation is a newer treatment modality in the patients with advanced cirrhosis, not responsible to medical treatment.

• Bulletin of the Korean Chemical Society
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• v.26 no.9
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• pp.1385-1389
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• 2005

Human hepatitis B virus (HBV) is a pathogen related to the development of liver diseases including chronic hepatitis, cirrhosis, and hepatocellular carcinoma (HCC). However, the efficient methods to suppress HBV replication have not been developed yet. Therefore, we have used RNA interference (RNAi) as a potential tool for the suppression of HBV replication. Here, we designed a 21 nt small intefering dsRNA (siRNA) against hepatitis B virus X (HBx) RNA with 3' overhanging ends derived from T7 promoter. It has been reported that HBV X protein plays an important role in HBV gene expression and viral replication. The suppression of HBx gene expression by the 21 nt siRNA was investigated by Northern blot analysis and chloramphenicol acetyl transferase (CAT) assay. The level of HBx mRNA was decreased by siRNA in a dose-dependent manner. We also found that the 21 nt siRNA inhibited the HBV replication in hepatocellular carcinoma cell.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.15 no.2
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• pp.63-73
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• 2012

Development of antiviral resistance to lamivudine is the most important factor for the treatment failure. It is necessary to establish proper guidelines to overcome drug resistance for children with chronic hepatitis B. Primary treatment with lamivudine should be considered if patients are in immune-clearance phase and have persistently elevated ALT levels more than twice the upper limit of normal value. Before initiating the therapy, careful consideration of the patient's status is required to exclude abnormal liver function tests due to other causes. The treatment option should be carefully decided to suppress the viral replication effectively. To obtain good compliance, clinicians should educate patients and their parents. Appropriate monitoring for virologic breakthrough and genotypic resistance is important in deciding to change the treatment plan. Sequential monotherapy should be avoided and a combination of drugs in other categories is recommended. New antiviral agents, such as entecavir and tenofovir, which have high potency and high genetic barrier, are soon expected to be available for use with children.

• Korean Journal of Veterinary Research
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• v.47 no.3
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• pp.285-290
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• 2007

The occurrence of hydropericardium-hepatitis syndrome was confirmed for the first time in Korea from chickens submitted for diagnosis to our laboratory from broiler and baeksemi farms. Clinical signs included depression, inappetence, ruffled feathers and an increase in mortality. At necropsy, severe hydropericardium and hepatic necrosis was characteristically found. The most remarkable microscopic changes were seen in the liver, including basophilic intranuclear inclusion bodies in the hepatocytes, massive hemorrhages and necrosis in the liver parenchyma. Based on polymerase chain reaction and transmission electron microscopy (TEM), we could identify the fowl adenoviruses as the causative agent of the disease. In the TEM, we observed the presence of a large number of intranuclear virus particles in the hepatocytes. We could also find the PCR amplification of 700 bp DNA from purified hydropericardium-hepatitis syndrome viral DNA.

• Journal of Biomedical Engineering Research
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• v.14 no.4
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• pp.341-348
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• 1993

Automated system to analyze liver function test results is presented based on fuzzy logic knowledge. Clinician's knowledge and experience was first expressed in linguistic terms fol- lowed by conversion to numerical values to create membership functions of disease possibility for each test item and liver disease. Membership functions were then compensated for different relative importances of test items. Liver diseases considered were acute viral hepatitis (AVH), chronic persistent hepatitis(CPH), chronic active hepatitis(CAH), and liver cirrhosis(LC), Liver function test results of alanine aminotransferase(ALT), aspartate amino- transferase(AST) , glutamate dehydrogenase(GDH), ornithine carbamyltransferase(OCT) , ALT/AST, and 10* GDH/ALT in 218 patients were analyzed by the present system, welch resulted in 80% accuracy. AVH and CAH showed the highest 93 % and the lowest 58% ac- curacies, respectively, which was similar to the clinician's expectation. The simple mathemat- ical formulation of the present system would enable an easy implementation in commercial analysis instruments. Also, the identical fuzzy logic can be applied to similar diagnostic envi- ronments in general.