Gastroenterology Publications and Presentations Copyright (c) 2013 University of Massachusetts Medical School All rights reserved. http://escholarship.umassmed.edu/gastroenterology_pp Recent documents in Gastroenterology Publications and Presentations en-us Wed, 13 Feb 2013 16:22:54 PST 3600 Dendritic cells in hepatitis C infection: can they (help) win the battle http://escholarship.umassmed.edu/gastroenterology_pp/124 http://escholarship.umassmed.edu/gastroenterology_pp/124 Mon, 29 Oct 2012 09:51:39 PDT Infection with hepatitis C virus (HCV) is a public health problem; it establishes a chronic course in ~85% of infected patients and increases their risk for developing liver cirrhosis, hepatocellular carcinoma, and significant extrahepatic manifestations. The mechanisms of HCV persistence remain elusive and are largely related to inefficient clearance of the virus by the host immune system. Dendritic cells (DCs) are the most efficient inducers of immune responses; they are capable of triggering productive immunity and maintaining the state of tolerance to self- and non-self antigens. During the past decade, multiple research groups have focused on DCs, in hopes of unraveling an HCV-specific DC signature or DC-dependent mechanisms of antiviral immunity which would lead to a successful HCV elimination strategy. This review incorporates the latest update in the current status of knowledge on the role of DCs in anti-HCV immunity as it relates to several challenging questions: (a) the phenotype and function of diverse DC subsets in HCV-infected patients; (b) the characteristics of non-human HCV infection models from the DCs' point of view; (c) how can in vitro systems, ranging from HCV protein- or peptide-exposed DC to HCV protein-expressing DCs, and in vivo systems, ranging from HCV protein-expressing transgenic mice to HCV-infected non-human primates, be employed to dissect the role of DCs in triggering/maintaining a robust antiviral response; and (d) the prospect of DC-based strategy for managing and finding a cure for HCV infection.

]]> Angela Dolganiuc et al. Animals Antiviral Agents Dendritic Cells Disease Models, Animal Hepacivirus Hepatitis C Humans Mice Viral Proteins Hepatocyte-specific hypoxia-inducible factor-1alpha is a determinant of lipid accumulation and liver injury in alcohol-induced steatosis in mice http://escholarship.umassmed.edu/gastroenterology_pp/123 http://escholarship.umassmed.edu/gastroenterology_pp/123 Mon, 29 Oct 2012 09:51:38 PDT Chronic alcohol causes hepatic steatosis and liver hypoxia. Hypoxia-regulated hypoxia-inducible factor 1-alpha, (HIF-1alpha) may regulate liporegulatory genes, but the relationship of HIF-1 to steatosis remains unknown. We investigated HIF-1alpha in alcohol-induced hepatic lipid accumulation. Alcohol administration resulted in steatosis, increased liver triglyceride levels, and increased serum alanine aminotransferase (ALT) levels, suggesting liver injury in wild-type (WT) mice. There was increased hepatic HIF-1alpha messenger RNA (mRNA), protein, and DNA-binding activity in alcohol-fed mice compared with controls. Mice engineered with hepatocyte-specific HIF-1 activation (HIF1dPA) had increased HIF-1alpha mRNA, protein, and DNA-binding activity, and alcohol feeding in HIF1dPA mice increased hepatomegaly and hepatic triglyceride compared with WT mice. In contrast, hepatocyte-specific deletion of HIF-1alpha [HIF-1alpha(Hep(-/-) )], protected mice from alcohol- and lipopolysaccharide (LPS)-induced liver damage, serum ALT elevation, hepatomegaly, and lipid accumulation. HIF-1alpha(Hep(-/-) ), WT, and HIF1dPA mice had equally suppressed levels of peroxisome proliferator-activated receptor alpha mRNA after chronic ethanol, whereas the HIF target, adipocyte differentiation-related protein, was up-regulated in WT mice but not HIF-1alpha(Hep(-/-) ) ethanol-fed/LPS-challenged mice. The chemokine monocyte chemoattractant protein-1 (MCP-1) was cooperatively induced by alcohol feeding and LPS in WT but not HIF-1alpha(Hep(-/-) ) mice. Using Huh7 hepatoma cells in vitro, we found that MCP-1 treatment induced lipid accumulation and increased HIF-1alpha protein expression as well as DNA-binding activity. Small interfering RNA inhibition of HIF-1alpha prevented MCP-1-induced lipid accumulation, suggesting a mechanistic role for HIF-1alpha in hepatocyte lipid accumulation.

CONCLUSION: Alcohol feeding results in lipid accumulation in hepatocytes involving HIF-1alpha activation. The alcohol-induced chemokine MCP-1 triggers lipid accumulation in hepatocytes via HIF-1alpha activation, suggesting a mechanistic link between inflammation and hepatic steatosis in alcoholic liver disease.

]]> Bharath D. Nath et al. Animals Fatty Liver, Alcoholic Hepatocytes Hypoxia-Inducible Factor 1, alpha Subunit *Lipid Metabolism Mice Mechanisms of alcohol-mediated hepatotoxicity in human-immunodeficiency-virus-infected patients http://escholarship.umassmed.edu/gastroenterology_pp/122 http://escholarship.umassmed.edu/gastroenterology_pp/122 Mon, 29 Oct 2012 09:51:37 PDT Clinical observations have demonstrated that excessive chronic alcohol use negatively affects human immunodeficiency virus (HIV) infection and contributes to the liver manifestations of the disease, even in HIV mono-infection. HIV/hepatitis C virus (HCV) co-infection is associated with increased progression of HVC liver disease compared to HCV infection alone, and both of these are negatively affected by alcohol use. Recent data suggest that alcohol use and HIV infection have common targets that contribute to progression of liver disease. Both HIV infection and chronic alcohol use are associated with increased gut permeability and elevated plasma levels of lipopolysaccharide; a central activator of inflammatory responses. Both alcoholic liver disease and HIV infection result in non-specific activation of innate immunity, proinflammatory cytokine cascade upregulation, as well as impaired antigen presenting cell and dendritic cell functions. Finally, alcohol, HIV and antiretroviral therapy affect hepatocyte functions, which contributes to liver damage. The common targets of alcohol and HIV infection in liver disease are discussed in this mini-review.

]]> Gyongyi Szabo et al. Antiretroviral Therapy, Highly Active Comorbidity Disease Progression HIV Infections Hepatitis B Hepatitis C Humans Liver Liver Diseases, Alcoholic Mitochondrial antiviral signaling protein defect links impaired antiviral response and liver injury in steatohepatitis in mice http://escholarship.umassmed.edu/gastroenterology_pp/121 http://escholarship.umassmed.edu/gastroenterology_pp/121 Mon, 29 Oct 2012 09:51:36 PDT Mitochondrial dysfunction is a pathogenic feature of nonalcoholic steatohepatitis (NASH). NASH complicates hepatotropic viral disease. The mitochondrial antiviral signaling protein (MAVS) is the adapter of helicase receptors involved in sensing double-stranded RNA (dsRNA). We hypothesized that impaired MAVS function may contribute to insufficient antiviral response and liver damage in steatohepatitis. We identified reduced MAVS protein levels and increased MAVS association with the proteasome subunit alpha type 7 (PSMA7) in livers from mice given a methionine-choline-deficient (MCD) diet. Decreased association of MAVS with mitochondria and increased cytosolic cytochrome c indicated mitochondrial damage in steatohepatitis. In vivo administration of the synthetic dsRNA polyinosinic:polycytidylic acid [poly(I:C)], but not lipopolysaccharide or cytidine-phosphate-guanosine-rich DNA, resulted in impaired induction of type I interferons (IFNs) and proinflammatory cytokines in steatohepatitis. Consistent with a defect in helicase receptor-induced signaling, there was loss of poly(I:C)-induced translocation of MAVS to the cytosol and decreased IFN regulatory factor 3 phosphorylation. Caspases 1 and 8, both of which cleave MAVS, were increased in MCD diet-fed mice. At baseline, steatohepatitis was associated with increased serum alanine aminotransferase (ALT), apoptosis and caspase 3 activation compared with controls. In contrast to apoptosis in controls, necrosis was induced by poly(I:C) stimulation in steatohepatitis. Hepatocyte necrosis was indicated by elevated serum high-mobility group box protein-1 and ALT and was correlated with increased expression of receptor-interacting protein 3 (RIP3), a master regulator of necrosis. Increased expression of MAVS, PSMA7, and RIP3 messenger RNA was also present in human NASH livers.

CONCLUSION: Our novel findings suggest that mitochondrial damage in steatohepatitis extends to MAVS, an adapter of helicase receptors, resulting in inefficient type I IFN and inflammatory cytokine response but increased hepatocyte necrosis and RIP3 induction in response to a dsRNA viral challenge. These mechanisms may contribute to progressive liver damage and impaired viral clearance in NASH.

]]> Timea Csak et al. Adaptor Proteins, Signal Transducing Animals Apoptosis Biopsy Choline Deficiency Cytokines Disease Models, Animal Fatty Liver Female Humans Interferon Type I Liver Methionine Mice Mice, Inbred C57BL Mitochondria, Liver Poly I-C RNA, Double-Stranded Receptor-Interacting Protein Serine-Threonine Kinases Fatty acid and endotoxin activate inflammasomes in mouse hepatocytes that release danger signals to stimulate immune cells http://escholarship.umassmed.edu/gastroenterology_pp/120 http://escholarship.umassmed.edu/gastroenterology_pp/120 Mon, 29 Oct 2012 09:51:35 PDT The pathogenesis of nonalcoholic steatohepatitis (NASH) and inflammasome activation involves sequential hits. The inflammasome, which cleaves pro-interleukin-1beta (pro-IL-1beta) into secreted IL-1beta, is induced by endogenous and exogenous danger signals. Lipopolysaccharide (LPS), a toll-like receptor 4 ligand, plays a role in NASH and also activates the inflammasome. In this study, we hypothesized that the inflammasome is activated in NASH by multiple hits involving endogenous and exogenous danger signals. Using mouse models of methionine choline-deficient (MCD) diet-induced NASH and high-fat diet-induced NASH, we found up-regulation of the inflammasome [including NACHT, LRR, and PYD domains-containing protein 3 (NALP3; cryopyrin), apoptosis-associated speck-like CARD-domain containing protein, pannexin-1, and pro-caspase-1] at the messenger RNA (mRNA) level increased caspase-1 activity, and mature IL-1beta protein levels in mice with steatohepatitis in comparison with control livers. There was no inflammasome activation in mice with only steatosis. The MCD diet sensitized mice to LPS-induced increases in NALP3, pannexin-1, IL-1beta mRNA, and mature IL-1beta protein levels in the liver. We demonstrate for the first time that inflammasome activation occurs in isolated hepatocytes in steatohepatitis. Our novel data show that the saturated fatty acid (FA) palmitic acid (PA) activates the inflammasome and induces sensitization to LPS-induced IL-1beta release in hepatocytes. Furthermore, PA triggers the release of danger signals from hepatocytes in a caspase-dependent manner. These hepatocyte-derived danger signals, in turn, activate inflammasome, IL-1beta, and tumor necrosis factor alpha release in liver mononuclear cells.

CONCLUSION: Our novel findings indicate that saturated FAs represent an endogenous danger in the form of a first hit, up-regulate the inflammasome in NASH, and induce sensitization to a second hit with LPS for IL-beta release in hepatocytes. Furthermore, hepatocytes exposed to saturated FAs release danger signals that trigger inflammasome activation in immune cells. Thus, hepatocytes play a key role in orchestrating tissue responses to danger signals in NASH.

]]> Timea Csak et al. Animals Apoptosis Caspase 1 Choline Deficiency Dietary Fats Disease Models, Animal Endotoxins Fatty Acids Fatty Liver Female Hepatocytes Immune System Inflammasomes Interleukin-1beta Methionine Mice Mice, Inbred C57BL Tumor Necrosis Factor-alpha Lipopolysaccharide induces and activates the Nalp3 inflammasome in the liver http://escholarship.umassmed.edu/gastroenterology_pp/119 http://escholarship.umassmed.edu/gastroenterology_pp/119 Mon, 29 Oct 2012 09:51:34 PDT AIM: To examine the activation of the Nalp3 inflammasome and its downstream targets following lipopolysaccharide (LPS)-induced stimulation in the liver.

METHODS: Six-to-eight-week-old C57BL/6 chow fed mice were injected intraperitoneally with 0.5 mug/g bodyweight LPS and sacrificed 2, 4, 6, 18 or 24 h later. LPS-induced liver damage was confirmed by a biochemical assay to detect alanine aminotransferase (ALT) levels. To determine if LPS stimulation in the liver led to activation of the inflammasome, real-time quantitative polymerase chain reaction was used to evaluate the mRNA expression of components of the Nalp3 inflammasome. Enzyme-linked immunosorbent assays were used to determine the protein expression levels of several downstream targets of the Nalp3 inflammasome, including caspase-1 and two cytokine targets of caspase-1, interleukin (IL)-1beta and IL-18.

RESULTS: We found that LPS injection resulted in liver damage as indicated by elevated ALT levels. This was associated with a significant increase in both mRNA and protein levels of the proinflammatory cytokine tumor necrosis factor (TNF)-alpha in the liver, as well as increased levels of TNFs in serum. We showed that LPS stimulation led to upregulation of mRNA levels in the liver for all the receptor components of the inflammasome, including Nalp3, Nalp1, pannexin-1 and the adaptor molecule apoptosis-associated speck-like, caspase recruitment domain-domain containing protein. We also found increased levels of mRNA and protein for caspase-1, a downstream target of the inflammasome. In addition, LPS challenge led to increased levels of both mRNA and protein in the liver for two cytokine targets of caspase-1, IL-1beta and IL-18. Interestingly, substantial baseline expression of pre-IL-1beta and pre-IL-18 was found in the liver. Inflammasome and caspase-1 activation was indicated by the significant increase in the active forms of IL-1beta and IL-18 after LPS stimulation.

CONCLUSION: Our results show that the Nalp3 inflammasome is upregulated and activated in the liver in response to LPS stimulation.

]]> Michal Ganz et al. Animals Carrier Proteins Cytokines Inflammasomes Lipopolysaccharides Liver Mice Mice, Inbred C57BL Advanced molecular biologic techniques in toxicologic disease http://escholarship.umassmed.edu/gastroenterology_pp/118 http://escholarship.umassmed.edu/gastroenterology_pp/118 Mon, 29 Oct 2012 09:51:33 PDT The advancement of molecular biologic techniques and their capabilities to answer questions pertaining to mechanisms of pathophysiologic events have greatly expanded over the past few years. In particular, these opportunities have provided researchers and clinicians alike the framework from with which to answer clinical questions not amenable for elucidation using previous, more antiquated methods. Utilizing extremely small molecules, namely microRNA, DNA, protein, and nanoparticles, we discuss the background and utility of these approaches to the progressive, practicing physician. Finally, we consider the application of these tools employed as future bedside point of care tests, aiding in the ultimate goal of unsurpassed patient care.

]]> Jeanine Ward et al. *Drug Toxicity Gene Expression Profiling Genomics Humans Metabolomics MicroRNAs Molecular Biology Proteomics Systems Biology An essential role for monocyte chemoattractant protein-1 in alcoholic liver injury: regulation of proinflammatory cytokines and hepatic steatosis in mice http://escholarship.umassmed.edu/gastroenterology_pp/117 http://escholarship.umassmed.edu/gastroenterology_pp/117 Mon, 29 Oct 2012 09:51:32 PDT The importance of chemokines in alcoholic liver injury has been implicated. The role of the chemokine, monocyte chemoattractant protein-1 (MCP-1), elevated in patients with alcoholic liver disease is not yet understood. Here, we evaluated the pathophysiological significance of MCP-1 and its receptor, chemokine (C-C motif) receptor 2 (CCR2), in alcoholic liver injury. The Leiber-DeCarli diet containing alcohol or isocaloric control diets were fed to wild-type (WT) and MCP-1-deficient knockout (KO) mice for 6 weeks. In vivo and in vitro assays were performed to study the role of MCP-1 in alcoholic liver injury. MCP-1 was increased in Kupffer cells (KCs) as well as hepatocytes of alcohol-fed mice. Alcohol feeding increased serum alanine aminotransferase in WT and CCR2KO, but not MCP-1KO, mice. Alcohol-induced liver steatosis and triglyceride were attenuated in alcohol-fed MCP-1KO, but high in CCR2KO mice, compared to WT, whereas serum endotoxin was high in alcohol-fed WT and MCP-1KO mice. Expression of liver proinflammatory cytokines tumor necrosis factor alpha, interleukin (IL)-1beta, IL-6, KC/IL-8, intercellular adhesion molecule 1, and cluster of differentiation 68 was induced in alcohol-fed WT, but inhibited in MCP-1KO, mice independent of nuclear factor kappa light-chain enhancer of activated B cell activation in KCs. Oxidative stress, but not cytochrome P450 2E1, was prevented in chronic alcohol-fed MCP-1KO mice, compared to WT. Increased expression of peroxisome proliferator-activated receptor (PPAR)alpha and PPARgamma was accompanied by nuclear translocation, DNA binding, and induction of fatty acid metabolism genes acyl coenzyme A oxidase and carnitine palmitoyltransferase 1A in livers of alcohol-fed MCP-1KO mice, compared to WT controls. In vitro assays uncovered an inhibitory effect of recombinant MCP-1 on PPARalpha messenger RNA and peroxisome proliferator response element binding in hepatocytes independent of CCR2. Conclusion: Deficiency of MCP-1 protects mice against alcoholic liver injury, independent of CCR2, by inhibition of proinflammatory cytokines and induction of genes related to fatty acid oxidation, linking chemokines to hepatic lipid metabolism.

]]> Pranoti Mandrekar et al. Acyl-CoA Oxidase Animals Carnitine O-Palmitoyltransferase Cell Line, Tumor Chemokine CCL2 Cytokines Fatty Liver, Alcoholic Female Hepatocytes Humans Kupffer Cells Lipopolysaccharides Liver Liver Diseases, Alcoholic Mice Mice, Inbred C57BL Mice, Knockout Oxidative Stress Peroxisome Proliferator-Activated Receptors Receptors, CCR2 MicroRNA Signature in Alcoholic Liver Disease http://escholarship.umassmed.edu/gastroenterology_pp/116 http://escholarship.umassmed.edu/gastroenterology_pp/116 Mon, 29 Oct 2012 09:51:31 PDT Alcoholic liver disease (ALD) is a major global health problem. Chronic alcohol use results in inflammation and fatty liver, and in some cases, it leads to fibrosis and cirrhosis or hepatocellular carcinoma. Increased proinflammatory cytokines, particularly TNF alpha, play a central role in the pathogenesis of ALD. TNF alpha is tightly regulated at transcriptional and posttranscriptional levels. Recently, microRNAs (miRNAs) have been shown to modulate gene functions. The role of miRNAs in ALD is getting attention, and recent studies suggest that alcohol modulates miRNAs. Recently, we showed that alcohol induces miR-155 expression both in vitro (RAW 264.7 macrophage) and in vivo (Kupffer cells, KCs of alcohol-fed mice). Induction of miR-155 contributed to increased TNF alpha production and to the sensitization of KCs to produce more TNF alpha in response to LPS. In this paper, we summarize the current knowledge of miRNAs in ALD and also report increased expression of miR-155 and miR-132 in the total liver as well as in isolated hepatocytes and KCs of alcohol-fed mice. Our novel finding of the alcohol-induced increase of miRNAs in hepatocytes and KCs after alcohol feeding provides further insight into the evolving knowledge regarding the role of miRNAs in ALD.

]]> Shashi Bala et al. MicroRNAs Liver Diseases, Alcoholic Molecular hepatic carcinogenesis: impact of inflammation http://escholarship.umassmed.edu/gastroenterology_pp/115 http://escholarship.umassmed.edu/gastroenterology_pp/115 Mon, 29 Oct 2012 09:51:30 PDT Hepatocellular cancer (HCC) represents one of the most rapidly spreading cancers in the world. Most HCC develops in cirrhotic livers after prolonged inflammation, supporting the hypothesis that inflammation contributes to cancer development. Increasing evidence suggests that inflammatory cell recruitment and activation is an important contributor to promoting cancerous malformation in hepatocytes. Intracellular signaling pathways involved in classical inflammatory pathway activation can be altered in parenchymal cells, hepatocytes, in the liver to promote HCC development. Inflammation is triggered by pathogen-derived or endogenous danger-associated molecular patterns via pattern recognition receptors. Activation of the pattern recognition receptors triggers downstream signaling cascades to induce proinflammatory cytokine production, release of reactive oxygen species and modulate cellular responses. Many of these inflammatory mediators have adverse effects on DNA repair and induce DNA methylation, both of which are important elements in HCC development. This review summarizes the key points and discusses recent findings related to the role of inflammation in cancer and HCC development.

]]> Gyongyi Szabo et al. Carcinoma, Hepatocellular Inflammation Hypoxia and hypoxia inducible factors: diverse roles in liver diseases http://escholarship.umassmed.edu/gastroenterology_pp/114 http://escholarship.umassmed.edu/gastroenterology_pp/114 Mon, 29 Oct 2012 09:51:30 PDT Hypoxia has been shown to have a role in the pathogenesis of several forms of liver disease. The hypoxia inducible factors (HIFs) are a family of evolutionarily conserved transcriptional regulators that affect a homeostatic response to low oxygen tension and have been identified as key mediators of angiogenesis, inflammation, and metabolism. In this review we summarize the evidence for a role of HIFs across a range of hepatic pathophysiology. We describe regulation of the HIFs and review investigations that demonstrate a role for HIFs in the development of liver fibrosis, activation of innate immune pathways, hepatocellular carcinoma, as well as other liver diseases in both human disease as well as murine models.

]]> Bharath D. Nath et al. Acetaminophen Animals Anoxia Humans Hypoxia-Inducible Factor 1 Immunity, Innate Lipid Metabolism Liver Liver Diseases *Liver Regeneration Metals Oxygen Reperfusion Injury Sleep Apnea, Obstructive Novel developmental biology-based protocol of embryonic stem cell differentiation to morphologically sound and functional yet immature hepatocytes http://escholarship.umassmed.edu/gastroenterology_pp/113 http://escholarship.umassmed.edu/gastroenterology_pp/113 Mon, 29 Oct 2012 09:51:29 PDT BACKGROUND/AIMS: Liver diseases are common in the United States and often require liver transplantation; however, donated organs are limited and thus alternative sources for liver cells are in high demand. Embryonic stem cells (ESC) can provide a continuous and readily available source of liver cells. ESC differentiation to liver cells is yet to be fully understood and comprehensive differentiation protocols are yet to be defined. Here, we aimed to achieve human (h)ESC differentiation into mature hepatocytes using defined recombinant differentiation factors and metabolites.

METHODS: Embryonic stem cell H1 line was sub-cultured on feeder layer. We induced hESCs into endodermal differentiation succeeded by early/late hepatic specification and finally into hepatocyte maturation using step combinations of Activin A and fibroblast growth factor (FGF)-2 for 7 days; followed by FGF-4 and bone morphogenic protein 2 (BMP2) for 7 days, succeeded by FGF-10 + hepatocyte growth factor 4 + epidermal growth factor for 14 days. Specific inhibitors/stimulators were added sequentially throughout differentiation. Cells were analysed by PCR, flow cytometry, microscopy or functional assays.

RESULTS: Our hESC differentiation protocol resulted in viable cells with hepatocyte shape and morphology. We observed gradual changes in cell transcriptome, including up-regulation of differentiation-promoting GATA4, GATA6, POU5F1 and HNF4 transcription factors, steady levels of stemness-promoting SOX-2 and low levels of Nanog, as defined by PCR. The hESC-derived hepatocytes expressed alpha-antitrypsin, CD81, cytokeratin 8 and low density lipoprotein (LDL) receptor. The levels of alpha-fetoprotein and proliferation marker Ki-67 in hESC-derived hepatocytes remained elevated. Unlike stem cells, the hESC-derived hepatocytes performed LDL uptake, produced albumin and alanine aminotransferase and had functional alcohol dehydrogenase.

CONCLUSION: We report a novel protocol for hESC differentiation into morphological and functional yet immature hepatocytes as an alternative method for hepatocyte generation.

]]> Terence N. Bukong et al. Activins Bone Morphogenetic Protein 2 Cell Differentiation Cell Proliferation Cell Survival Cells, Cultured Drug Combinations Embryonic Stem Cells Fibroblast Growth Factors Flow Cytometry Hepatocytes Humans Polymerase Chain Reaction Research Design Transcription Factors Up-Regulation CD81/CD9 tetraspanins aid plasmacytoid dendritic cells in recognition of HCV-infected cells and induction of IFNalpha http://escholarship.umassmed.edu/gastroenterology_pp/112 http://escholarship.umassmed.edu/gastroenterology_pp/112 Mon, 29 Oct 2012 09:51:28 PDT Recognition of hepatitis C virus (HCV)-infected hepatocyes and interferon (IFN) induction are critical in antiviral immune response. We hypothesized that cell-cell contact between plasmacytoid dendritic cells (pDCs) and HCV-infected cells was required for IFNalpha induction via involvement of cell surface molecules. Co-culture of human peripheral blood mononuclear cells (PBMCs) with genotype 1a full length HCV genomic replicon cells (FL) or genotype 2a JFH-1 virus infected hepatoma cells (JFH-1), not with uninfected hepatoma cells (Huh7.5), induced IFNalpha production. Depletion of pDCs from PBMCs attenuated IFNalpha release and purified pDCs produced high levels of IFNalpha after co-culture with FL replicons or JFH-1 infected cells. IFNalpha induction by HCV-containing hepatoma cells required viral replication, direct cell-cell contact with pDCs, and receptor-mediated endocytosis. We determined that the tetraspanin proteins, CD81 and CD9 and not other HCV entry receptors were required for IFNalpha induction in pDCs by HCV infected hepatoma cells. Disruption of cholesterol-rich membrane microdomains, the localization site of CD81 or inhibition of CD81 downstream molecule, Rac GTPase, inhibited IFNalpha production. IFNalpha induction involved HCV RNA and Toll-like receptor 7 (TLR7). IFNalpha production by HCV infected hepatoma cells was decreased in pDCs from HCV infected patients compared to normal controls. We found that pre-exposure of normal PBMCs to HCV viral particles attenuated IFNalpha induction by HCV infected hepatoma cells or TLR ligands and this inhibitory effect could be prevented by an anti-HCV E2 blocking antibody. In conclusion, our novel data show that recognition of HCV-infected hepatoma cells by pDCs involves CD81/CD9-associated membrane microdomains and induces potent IFNalpha production. (HEPATOLOGY 2012.).

]]> Shuye Zhang et al. Hepatitis C Antigens, CD81 Antigens, CD9 Interferon-alpha Circulating microRNAs in exosomes indicate hepatocyte injury and inflammation in alcoholic, drug-induced, and inflammatory liver diseases http://escholarship.umassmed.edu/gastroenterology_pp/111 http://escholarship.umassmed.edu/gastroenterology_pp/111 Mon, 29 Oct 2012 09:51:27 PDT MicroRNAs are fine tuners of diverse biological responses and are expressed in various cell types of the liver. Here we hypothesized that circulating microRNAs (miRNAs) may serve as biomarkers of liver damage and inflammation. We studied miRNA-122, which is abundant in hepatocytes, and miR-155, -146a, and -125b, which regulate inflammation in immune cells in mouse models of alcoholic liver disease (ALD), drug (acetaminophen, APAP)-induced liver injury (DILI), and Toll-like receptor (TLR) 9+4 ligand-induced inflammatory cell-mediated liver damage. We found that serum/plasma miR-122 correlated with alanine aminotransferase (ALT) increases in the liver damage caused by alcohol, APAP, and TLR9 (CpG)+4 (LPS) ligands. MiR-155, a regulator of inflammation, was increased in serum/plasma in alcoholic and inflammatory liver injury. Alcohol failed to increase serum miR-122 in TLR4-deficient and p47phox-deficient mice that were protected from ALD. We found the most robust increase in plasma miR-122 in DILI and it correlated with the highest ALT levels. Consistent with the massive inflammatory cell infiltration in the liver, plasma miR-155 and miR-146a were significantly elevated after CpG+LPS administration. We show for the first time that, depending on the type of liver injury, circulating miRNAs are associated either with the exosome-rich or protein-rich compartments. In ALD and in inflammatory liver injury, serum/plasma miR-122 and miR-155 were predominantly associated with the exosome-rich fraction, whereas in DILI/APAP injury these miRNAs were present in the protein-rich fraction. Conclusion: Our results suggest that circulating miRNAs may serve as biomarkers to differentiate between hepatocyte injury and inflammation and the exosome versus protein association of miRNAs may provide further specificity to mechanisms of liver pathology. (HEPATOLOGY 2012).

]]> Shashi Bala et al. MicroRNAs Hepatocytes Liver Diseases Reduction in Hepatic Inflammation Is Associated With Less Fibrosis Progression and Fewer Clinical Outcomes in Advanced Hepatitis C http://escholarship.umassmed.edu/gastroenterology_pp/110 http://escholarship.umassmed.edu/gastroenterology_pp/110 Mon, 29 Oct 2012 09:51:26 PDT OBJECTIVES:During the Hepatitis C Antiviral Long-term Treatment against Cirrhosis Trial, 3.5 years of maintenance peginterferon-alfa-2a therapy did not affect liver fibrosis progression or clinical outcomes among 1,050 previous interferon nonresponders with advanced fibrosis or cirrhosis. We investigated whether reduced hepatic inflammation was associated with clinical benefit in 834 patients with a baseline and follow-up biopsy 1.5 years after randomization to peginterferon or observation.

METHODS:Relationships between change in hepatic inflammation (Ishak hepatic activity index, (HAI)) and serum alanine aminotransferase level, fibrosis progression and clinical outcomes after randomization, and hepatitis C virus (HCV) RNA decline before and after randomization were evaluated. Histological change was defined as a >/=2-point difference in HAI or Ishak fibrosis score between biopsies.RESULTS:Among 657 patients who received full-dose peginterferon/ribavirin "lead-in" therapy before randomization, year-1.5 HAI improvement was associated with lead-in HCV RNA suppression in both the randomized treated (P

CONCLUSIONS:Reduced hepatic inflammation (measured 1.5 and 3.5 years after randomization) was associated with profound virological suppression during lead-in treatment with full-dose peginterferon/ribavirin and with decreased fibrosis progression and clinical outcomes, independent of randomized treatment.Am J Gastroenterol advance online publication, 12 June 2012; doi:10.1038/ajg.2012.137.

]]> Chihiro Morishima et al. Hepatitis C Inflammation Plasma microRNA profiles distinguish lethal injury in acetaminophen toxicity: a research study http://escholarship.umassmed.edu/gastroenterology_pp/109 http://escholarship.umassmed.edu/gastroenterology_pp/109 Mon, 29 Oct 2012 09:51:25 PDT AIM: To investigate plasma microRNA (miRNA) profiles indicative of hepatotoxicity in the setting of lethal acetaminophen (APAP) toxicity in mice.

METHODS: Using plasma from APAP poisoned mice, either lethally (500 mg/kg) or sublethally (150 mg/kg) dosed, we screened commercially available murine microRNA libraries (SABiosciences, Qiagen Sciences, MD) to evaluate for unique miRNA profiles between these two dosing parameters.

RESULTS: We distinguished numerous, unique plasma miRNAs both up- and downregulated in lethally compared to sublethally dosed mice. Of note, many of the greatest up- and downregulated miRNAs, namely 574-5 p, 466 g, 466 f-3p, 375, 29 c, and 148 a, have been shown to be associated with asthma in prior studies. Interestingly, a relationship between APAP and asthma has been previously well described in the literature, with an as yet unknown mechanism of pathology. There was a statistically significant increase in alanine aminotransferase levels in the lethal compared to sublethal APAP dosing groups at the 12 h time point (P < 0.001). There was 90% mortality in the lethally compared to sublethally dosed mice at the 48 h time point (P = 0.011).

CONCLUSION: We identified unique plasma miRNAs both up- and downregulated in APAP poisoning which are correlated to asthma development.

]]> Jeanine Ward et al. Acetaminophen MicroRNAs Increased microRNA-155 expression in the serum and peripheral monocytes in chronic HCV infection http://escholarship.umassmed.edu/gastroenterology_pp/108 http://escholarship.umassmed.edu/gastroenterology_pp/108 Mon, 29 Oct 2012 09:51:24 PDT BACKGROUND: Hepatitis C Virus (HCV), a single stranded RNA virus, affects millions of people worldwide and leads to chronic infection characterized by chronic inflammation in the liver and in peripheral immune cells. Chronic liver inflammation leads to progressive liver damage. MicroRNAs (miRNA) regulate inflammation (miR-155, -146a and -125b) as well as hepatocyte function (miR-122).

METHODS: Here we hypothesized that microRNAs are dysregulated in chronic HCV infection. We examined miRNAs in the circulation and in peripheral monocytes of patients with chronic HCV infection to evaluate if specific miRNA expression correlated with HCV infection.

RESULTS: We found that monocytes from chronic HCV infected treatment-naive (cHCV) but not treatment responder patients showed increased expression of miR-155, a positive regulator of TNFalpha, and had increased TNFalpha production compared to monocytes of normal controls. After LPS stimulation, miR-155 levels were higher in monocytes from cHCV patients compared to controls. MiR-125b, which has negative regulatory effects on inflammation, was decreased in cHCV monocytes compared to controls. Stimulation of normal monocytes with TLR4 and TLR8 ligands or HCV core, NS3 and NS5 recombinant proteins induced a robust increase in both miR-155 expression and TNFalpha production identifying potential mechanisms for in vivo induction of miR-155. Furthermore, we found increased serum miR-155 levels in HCV patients compared to controls. Serum miR-125b and miR-146a levels were also increased in HCV patients. Serum levels of miR-122 were elevated in cHCV patients and correlated with increased ALT and AST levels and serum miR-155 levels.

CONCLUSION: In conclusion, our novel data demonstrate that miR-155, a positive regulator of inflammation, is upregulated both in monocytes and in the serum of patients with chronic HCV infection. Our study suggests that HCV core, NS3, and NS5 proteins or TLR4 and TLR8 ligands can mediate increased miR-155 and TNFalpha production in chronic HCV infection. The positive correlation between serum miR-155 and miR-122 increase in cHCV may be an indicator of inflammation-induced hepatocyte damage.

]]> Shashi Bala et al. Hepatitis C, Chronic MicroRNAs Human Monoclonal Antibody HCV1 Effectively Prevents and Treats HCV Infection in Chimpanzees http://escholarship.umassmed.edu/gastroenterology_pp/107 http://escholarship.umassmed.edu/gastroenterology_pp/107 Mon, 29 Oct 2012 09:51:23 PDT Hepatitis C virus (HCV) infection is a leading cause of liver transplantation and there is an urgent need to develop therapies to reduce rates of HCV infection of transplanted livers. Approved therapeutics for HCV are poorly tolerated and are of limited efficacy in this patient population. Human monoclonal antibody HCV1 recognizes a highly-conserved linear epitope of the HCV E2 envelope glycoprotein (amino acids 412-423) and neutralizes a broad range of HCV genotypes. In a chimpanzee model, a single dose of 250 mg/kg HCV1 delivered 30 minutes prior to infusion with genotype 1a H77 HCV provided complete protection from HCV infection, whereas a dose of 50 mg/kg HCV1 did not protect. In addition, an acutely-infected chimpanzee given 250 mg/kg HCV1 42 days following exposure to virus had a rapid reduction in viral load to below the limit of detection before rebounding 14 days later. The emergent virus displayed an E2 mutation (N415K/D) conferring resistance to HCV1 neutralization. Finally, three chronically HCV-infected chimpanzees were treated with a single dose of 40 mg/kg HCV1 and viral load was reduced to below the limit of detection for 21 days in one chimpanzee with rebounding virus displaying a resistance mutation (N417S). The other two chimpanzees had 0.5-1.0 log(10) reductions in viral load without evidence of viral resistance to HCV1. In vitro testing using HCV pseudovirus (HCVpp) demonstrated that the sera from the poorly-responding chimpanzees inhibited the ability of HCV1 to neutralize HCVpp. Measurement of antibody responses in the chronically-infected chimpanzees implicated endogenous antibody to E2 and interference with HCV1 neutralization although other factors may also be responsible. These data suggest that human monoclonal antibody HCV1 may be an effective therapeutic for the prevention of graft infection in HCV-infected patients undergoing liver transplantation.

]]> Trevor J. Morin et al. Hepatitis C Antibodies MicroRNA silencing and the development of novel therapies for liver disease http://escholarship.umassmed.edu/gastroenterology_pp/106 http://escholarship.umassmed.edu/gastroenterology_pp/106 Mon, 29 Oct 2012 09:51:22 PDT In recent years microRNAs have emerged as crucial small non-coding RNA molecules with diverse roles in various diseases including diseases of the liver. In this review, we highlight the latest advances in the field of microRNA biology and their potential as emerging therapeutic targets in liver disease. Elsevier B.V. All rights reserved.

]]> Gyongyi Szabo et al. MicroRNAs Liver Diseases RNA, Small Interfering The Presence of p47phox in Liver Parenchymal Cells is a Key Mediator in the Pathogenesis of Alcoholic Liver Steatosis http://escholarship.umassmed.edu/gastroenterology_pp/105 http://escholarship.umassmed.edu/gastroenterology_pp/105 Mon, 29 Oct 2012 09:51:21 PDT BACKGROUND: Reactive oxygen species contribute to steatosis and inflammation in alcoholic liver disease (ALD). Here, we evaluated the selective contribution of p47phox, a critical subunit of nicotinamide adenine dinucleotide phosphate oxidase (NADPH) oxidase complex, in liver parenchymal cells and in bone marrow (BM)-derived cells.

METHODS: Female C57Bl/6 wild type [WT], total body p47phox-deficient knockout [KO] or p47phox chimera mice generated by BM transplantation of p47phox-KO-BM into irradiated WT mice (WT/p47phox-KO-BM mice) received 5% Lieber-DeCarli alcohol or control (pair feeding) diet for 4 weeks.

RESULTS: Alcohol-induced liver steatosis as measured by Oil Red O staining and serum triglyceride up-regulation were prevented in p47phox-KO mice but not in WT/p47phox-KO-BM chimeras compared to WT controls. Serum alanine aminotransferase (ALT) was significantly increased in alcohol-fed WT mice but not in p47phox-KO mice compared to pair-fed controls. There was no protection from alcohol-induced increase in ALT and liver damage in the WT/p47phox-KO-BM mice. Alcohol-induced liver steatosis was accompanied by up-regulation of the lipid droplet-stabilizing protein, adipocyte differentiation-related protein (ADRP), and the fatty acid synthesis-associated genes, fatty acid synthase (FASN) and acetyl-CoA carboxylase (ACACA). Total body deficiency in p47phox but not selective absence of p47phox in BM-derived cells prevented alcohol-induced up-regulation of ADRP, FASN, and ACACA in the liver. Finally, alcohol-induced activation and DNA binding of nuclear factor kappaB (NF-kappaB), a master regulator of inflammation, were significantly increased after alcohol feeding in WT but not in p47phox-KO mice. Selective deficiency of p47phox in BM-derived cells (WT/p47phox-KO-BM chimera) failed to prevent NF-kappaB induction after alcohol feeding.

CONCLUSIONS: Total body deficiency in p47phox subunit of NADPH oxidase complex protects mice from alcohol-induced liver steatosis via mechanisms involving ADRP, FASN, and ACACA as well as from alcohol-induced NF-kappaB activation. In contrast, selective absence of p47phox in BM-derived cells fails to provide protection via these mechanisms. These results suggest that p47phox in parenchymal cells plays a critical role in the pathogenesis of ALD.

]]> Ivan Levin et al. Fatty Liver, Alcoholic NADPH Oxidase