Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0019158 (hepatitis)
 30,205 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The functions of resident antigen-presenting cells (APC) may be compromised in inflammatory microenvironment of the host. However, little is known regarding the phenotype and function of the liver resident APC in this condition. This issue was addressed by evaluating the function of liver dendritic cells (DC) from mice with concanavalin-A-induced experimental hepatitis. In sharp contrast to normal mice, the expressions of MHC class II and CD86 antigens were not upregulated on liver DC from mice with hepatitis due to interactions with specific antigens like hepatitis B surface antigen and keyhole limpet hemocyanin. Accordingly, these DC were completely unable to induce proliferation of antigen-specific memory lymphocytes. Moreover, liver DC from mice with hepatitis produced significantly lower levels of interleukin-12 and interferon-gamma compared with those from control mice. The lack of antigen internalization capacity of liver DC from mice with hepatitis was evident from their low endocytosis capacity. These data indicate that impaired antigen capturing and T cell activating capacity of liver DC may contribute to low magnitude of antigen-specific immune responses in mice with experimental hepatitis.
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PMID:Inability of liver dendritic cells from mouse with experimental hepatitis to process and present specific antigens. 1278 6

The pathogenesis of hepatitis C virus-induced chronic liver disease is still poorly understood. Previous studies revealed enhanced hepatic expression of the Th1 prototype cytokine IFN-gamma in individuals with chronic hepatitis C. In accordance with several animal models of experimentally induced hepatitis, a Th1 lymphocyte driven inflammatory process, which involves newly infiltrated as well as resident monocytes/macrophages, has been proposed. An involvement of the interferon-gamma-inducible chemokine IP-10, which is chemoattractive for stimulated Th1 cells and monocytes, is also suggested. Using an HBV transgenic mouse model, a reduction of hepatic infiltration and liver disease was achieved recently by administration of antibodies directed against the interferon-gamma-inducible chemokine Mig and against IP-10. In the present study, expression of IP-10 was investigated both in serum and in the liver of patients with chronic hepatitis C and hepatitis B. Patients with liver diseases of non-viral etiologies served as controls. IP-10 expression was highest in hepatitis C. In chronic hepatitis C, but not in chronic hepatitis B nor in liver disorders unrelated to viral infections, IP-10 expression was strongly correlated with the amount of transcripts for IFN-gamma and to the amount of transcripts for the constitutively expressed macrophage derived cytokine IL-18. Hepatic inflammatory activity, however, was found to be associated more closely with IFN-gamma than with IP-10 or IL-18 mRNA expression. The data support the hypothesis that IP-10 is responsible for the recruitment of Th cells and monocytes in chronic hepatitis C, and suggest that its role in chronic hepatitis B is less determining. Moreover, they deliver additional support for the view that IFN-gamma still has to be considered as a mediator that determines the outcome of inflammation, e.g., via its ability to activate IL-18 expressing cells and to initiate a delayed type hypersensitivity reaction.
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PMID:Expression of the chemokine IP-10 correlates with the accumulation of hepatic IFN-gamma and IL-18 mRNA in chronic hepatitis C but not in hepatitis B. 1279 18

Inflammation is commonly observed in liver diseases and is frequently complicated by fibrosis and cirrhosis in end-stage disease. The only curative treatment for cirrhotic patients is liver transplantation. However, organ shortage as well as an increasing organ demand call for early treatment of liver disease and prevention of fibrosis. Experimental data have shown the critical role of pro-inflammatory cytokines like tumor necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma) in the development of liver injury. Here, we review our work on the role of endogenously produced interleukin-10 (IL-10), a potent anti-inflammatory cytokine, in several experimental models of acute and chronic liver injury. First, in acute macrophage-mediated hepatitis induced by galactosamine/lipopolysaccharide administration, IL-10 neutralisation led to a more severe liver damage, whereas IL-10 injection, even delayed, was able to limit liver necrosis. A similar protective effect of IL-10 was observed in acute T cell-mediated hepatitis induced by concanavalin A (Con A) injection. The immunoregulatory role of IL-10 was then established after repeated exposition to Con A. In carbon tetrachloride liver injury, two other properties of IL-10 have been suggested: modulation of hepatocyte proliferation and modulation of liver fibrosis. Finally, the potential therapeutic applications in human liver disease as well as the potential side effects are discussed.
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PMID:Modulation of liver injury by interleukin-10. 1281 43

The therapeutic potential of cannabinoids has been described previously for several inflammatory diseases, but the molecular mechanisms underlying the anti-inflammatory properties of cannabinoids are not well understood. In this study, we investigated the mechanism of action of a novel synthetic cannabinoid, [(+)(6aS,10aS)-6,6-Dimethyl-3-(1,1-dimethylheptyl)-1-hydroxy-9-(1H-imidazol-2-ylsulfanylmethyl]-6a,7,10,10a-tetrahydro-6H-dibenzo[b,d]pyran (PRS-211,092) that has no psychotropic effects but exhibits immunomodulatory properties. Treatment with PRS-211,092 significantly decreased Concanavalin A-induced liver injury in mice that was accompanied by: 1) promotion of early gene expression of interleukin (IL)-6 and IL-10 that play a protective role in this model; 2) induction of early gene expression of the suppressors of cytokine signaling (SOCS-1 and 3), followed by 3) inhibition of several pro-inflammatory mediators, including IL-2, monocyte chemoattractant protein-1 (MCP-1), IL-1beta, interferon-gamma, and tumor necrosis factor alpha. Based on these results, we propose a mechanism by which PRS-211,092 stimulates the expression of IL-6, IL-10 and the SOCS proteins that, in turn, negatively regulates the expression of pro-inflammatory cytokines. Negative regulation by PRS-211,092 was further demonstrated in cultured T cells, where it inhibited IL-2 production and nuclear factor of activated T cells activity. These findings suggest that this cannabinoid derivative is an immunomodulator that could be developed as a potential drug for hepatitis as well as for other short- or long-term inflammatory diseases.
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PMID:A novel synthetic cannabinoid derivative inhibits inflammatory liver damage via negative cytokine regulation. 1464 63

Mice infected with the coronavirus mouse hepatitis virus, strain JHM (JHM) develop a disease that shares many histological characteristics with multiple sclerosis. We previously demonstrated that JHM-infected mice that only have CD8 T cells specific for an epitope not in the virus develop demyelination on specific activation of these cells. Herein we show that this process of bystander T-cell-mediated demyelination is interferon-gamma (IFN-gamma)-dependent. The absence of IFN-gamma abrogated demyelination but did not change T-cell infiltration or expression levels of inflammatory cytokines or chemokines in the spinal cord. These results are consistent with models in which IFN-gamma contributes to CD8 T-cell-mediated demyelination by activation of macrophages/microglia, the final effector cells in the disease process.
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PMID:Bystander CD8 T-cell-mediated demyelination is interferon-gamma-dependent in a coronavirus model of multiple sclerosis. 1474 42

The effects of secoisolariciresinol (1) and isotaxiresinol (2), two major lignans isolated from the wood of Taxus yunnanensis, on tumor necrosis factor-alpha (TNF-alpha)-dependent hepatic apoptosis induced by D-galactosamine (d-GalN)/lipopolysaccharide (LPS) were investigated in mice. Co-administration of d-GalN (700 mg/kg) and LPS (10 microg/kg) resulted in a typical hepatic apoptosis characterized by DNA fragmentation and the formation of apoptotic bodies. Serum glutamic pyruvic transaminase (sGPT) and glutamic oxaloacetic transaminase (sGOT) levels were also raised at 8 h after d-GalN/LPS intoxication due to a severe necrosis of hepatocytes. Pre-administration of 1 or 2 (50, 10 mg/kg, i.p.) 12 and 1 h before d-GalN/LPS significantly reduced DNA fragmentation and prevented chromatin condensation, apoptotic body formation and hepatitis. Pro-inflammatory cytokines such as TNF-alpha and interferon-gamma (IFN-gamma) secreted from LPS-activated macrophages are important mediators of hepatocyte apoptosis in this model. Pre-treatment with 1 or 2 significantly inhibited the elevation of serum TNF-alpha and IFN-gamma levels. In a separate experiment, both lignans had a significant dose-dependent protective effect on d-GalN/TNF-alpha-induced cell death in primary cultured mouse hepatocytes and TNF-alpha-mediated cell death in murine L929 fibrosarcoma cells. These results indicated that 1 and 2 prevent d-GalN/LPS-induced hepatic injury by inhibiting hepatocyte apoptosis through the blocking of TNF-alpha and IFN-gamma production by activated macrophages and direct inhibition of the apoptosis induced by TNF-alpha.
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PMID:Secoisolariciresinol and isotaxiresinol inhibit tumor necrosis factor-alpha-dependent hepatic apoptosis in mice. 1504 92

A proposed mechanism in the pathogenesis of biliary atresia involves an initial virus-induced, progressive T cell-mediated inflammatory obliteration of bile ducts. The aim of this study was to characterize the inflammatory environment present within the liver of infants with biliary atresia to gain insight into the role of a primary immune-mediated process versus a nonspecific secondary response to biliary obstruction. Frozen liver tissue obtained from patients with biliary atresia, neonatal giant cell hepatitis, total parenteral nutrition (TPN)-related cholestasis, choledochal cysts, and normal control subjects was used for fluorescent immunohistochemistry studies of cellular infiltrates, cytokine mRNA expression, and in situ hybridization for localization of cytokine-producing cells. Immunohistochemistry revealed increases in CD8(+) and CD4(+) T cells and Kupffer cells (CD68(+)) in the portal tracts of biliary atresia. Reverse transcription-PCR analysis of biliary atresia tissue showed a Th1-type cytokine profile with expression of IL-2, interferon-gamma, tumor necrosis factor-alpha, and IL-12. This profile was not seen in normal, neonatal hepatitis or choledochal cyst livers but was present in TPN-related cholestasis. In situ hybridization revealed that the Th1 cytokine-producing cells were located in the portal tracts in biliary atresia and in the parenchyma of TPN-related cholestasis. A distinctive portal tract inflammatory environment is present in biliary atresia, involving CD4(+) Th1 cell-mediated immunity. The absence of similar inflammation in other pediatric cholestatic conditions suggests that the portal tract inflammation in biliary atresia is not a secondary response to cholestasis but rather indicates a specific immune response involved in the pathogenesis of biliary atresia.
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PMID:Biliary atresia is associated with CD4+ Th1 cell-mediated portal tract inflammation. 1512 25

Interferon-alpha (IFN-alpha) is a potent suppressor of hepatitis B virus (HBV) replication in the HBV-transgenic mouse, depleting virus replication intermediates from infected hepatocytes via pathways mediated by interferon-gamma (IFN-gamma) and tumor necrosis factor alpha (TNF-alpha). It has also been hypothesized that cytokines induce curing of infected hepatocytes via non-cytolytic pathways during resolution of transient hepadnavirus infections. We have therefore evaluated therapy of chronic woodchuck hepatitis virus (WHV) infections using treatment with the nucleoside analog clevudine [L-FMAU; 1-(2-fluoro-5-methyl-b-L-arabinofuranosyl) uracil] and therapy with adenovirus vectors expressing INF-gamma, TNF-alpha, and beta-galactosidase. Before their use in vivo, expression of IFN-gamma and TNF-alpha from the adenovirus vectors was evaluated in vitro. Conditioned media from adenovirus-infected WC-3 cells was shown to inhibit WHV replication in baculovirus-transduced cells. Adenovirus super-infection of the liver in woodchucks led to declines in the percentage of hepatocytes with detectable core antigen and nucleic acids, and in levels of covalently closed circular DNA (cccDNA) and total WHV DNA, but a major long-term benefit of adenovirus super-infection during clevudine treatment was not demonstrated. Moreover, the effect took at least 2 weeks to develop suggesting that the declines in the percentage of WHV-infected cells, ccc, and total WHV DNA resulted from induction of the adaptive immune response by the adenovirus super-infection, and only indirectly from the expression of cytokines by the vectors.
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PMID:Adenovirus-based gene therapy during clevudine treatment of woodchucks chronically infected with woodchuck hepatitis virus. 1532 95

Mice with suppressor of cytokine signaling-1 (SOCS-1) deficiency die within 3 weeks of birth from a multiorgan inflammatory disease. Increased systemic levels and sensitivity of cells to the inflammatory cytokines interferon-gamma and tumor necrosis factor may contribute to the disease. Hepatitis and liver failure are thought to be the cause of the neonatal lethality in these mice. Here, we show that the pancreata of SOCS-1(-/-) mice are also severely affected by inflammation, displaying extensive edema and infiltration by T cells and macrophages. Acinar cells in particular were atrophied and reduced in their zymogen content. The expression of inflammatory markers, including class I major histocompatibility complex and inducible nitric oxide synthase, were increased in the SOCS-1(-/-) pancreas. Although there was generalized up-regulation of class I major histocompatibility complex, inducible nitric oxide synthase expression was more prominent on exocrine tissues. There appeared to be preferential damage and apoptosis of exocrine over endocrine components. Unexpectedly, increased islet neogenesis, possibly from proliferating ductal cells, was observed in the pancreas of SOCS-1(-/-) mice. This is reminiscent of the pancreatitis and islet neogenesis that occur in mice that transgenically overexpress interferon-gamma and/or tumor necrosis factor. This study suggests that in addition to liver failure, the pancreatitis may also be an important contributor to the neonatal lethality in SOCS-1(-/-) mice.
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PMID:Severe pancreatitis with exocrine destruction and increased islet neogenesis in mice with suppressor of cytokine signaling-1 deficiency. 1533 15

Acute hepatitis and recovery from woodchuck hepatitis virus (WHV) infection involves increased intrahepatic expression of interferon-gamma (IFN-gamma) and tumour necrosis factor-alpha (TNF-alpha) mRNAs. In the present study, recovery correlated with increased intrahepatic expression of mRNAs for major histocompatibility complex class 1 (MHC1), beta(2)-microglobulin, 2'5'-oligoadenylate synthetase (2'5'-OAS), and indoleamine dioxygenase (IDO). By comparison, acute WHV infection progressing to chronicity was associated with diminished expression of these IFN-gamma-associated mRNAs in liver. Transfection of WHV-infected primary hepatocytes (WPH) from WHV carriers with an IFN-gamma-expressing plasmid (pIFN-gamma) resulted in dose-dependent accumulations of MHC1, TNF-alpha, 2'5'-OAS, and IDO mRNAs within 96 h. Markers of T cells and immune-mediated cytotoxicity that accumulate in recovering liver were not apparent in WPH based on the relative lack of CD3, CD4, Fas ligand, perforin, and granzyme B mRNAs. Expression of pIFN-gamma, and TNF-alpha-expressing plasmid (pTNF-alpha), did not affect total WHV RNA, or fully double-stranded WHV DNA in WPH, but each reduced some of the replicative intermediate (RI) species of WHV DNA synthesis. WPH treated with recombinant IFN-alpha protein had a higher fold induction of 2'5'-OAS mRNA associated with partial reductions in WHV RNAs and the major RI species. Thus, IFN-gamma expression in carrier WPH induced several host responses often observed in liver of recovering woodchucks, and impaired a stage of WHV DNA synthesis by a non-cytolytic mechanism mediated by TNF-alpha. Local enhancement of IFN-gamma-associated responses in chronic WHV-infected hepatocytes may promote therapeutic antiviral effects, but additional effector mechanisms evident during recovery appear necessary for more complete clearance of WHV infection.
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PMID:Interferon-gamma-associated responses to woodchuck hepatitis virus infection in neonatal woodchucks and virus-infected hepatocytes. 1535 45


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