Gastroenterology Commons^™

Inhibition Of Antigen-Presenting Cell Functions By Alcohol: Implications For Hepatitis C Virus Infection, Gyongyi Szabo, Angela Dolganiuc, Pranoti Mandrekar, Bernadette White

Gyongyi Szabo

The mechanisms of alcohol-induced immunosuppression include defects in innate and adaptive immune responses. Monocytes and dendritic cells (DCs) link innate and adaptive immune responses as they recognize viral antigens and induce antigen-specific T-cell activation. We investigated the effects of alcohol on antigen-presenting cell functions. Acute alcohol consumption by healthy volunteers (vodka, 2 ml/kg) resulted in significantly reduced antigen-presenting cell function of monocyte-derived DCs. Reduced allostimulatory capacity of DCs treated with alcohol in vitro correlated with decreased co-stimulatory molecule (B7.1 and B7.2) expression, as well as with reduced interleukin (IL)-12 and increased IL-10 concentrations, in mixed lymphocyte cultures. Dendritic cells recognize …

Hepatitis C Infection And Alcohol Use: A Dangerous Mix For The Liver And Antiviral Immunity, Gyongyi Szabo, Costica Aloman, Stephen Polyak, Steven Weinman, Jack Wands, Samir Zakhari

Gyongyi Szabo

This article presents the proceedings of a symposium presented at the meeting of the Research Society on Alcoholism, held in Santa Barbara, California, in June 2005. The organizers and chairs were Sam Zakhari and Gyongyi Szabo. The presentations included (1) Mitochondrial Abnormalities Induced by Hepatitis C -Alcohol Interaction by Steven Weinman; (2) Effects of Acute and Chronic Ethanol on Innate Antiviral Signaling Pathways, Hepatitis C Replication, and Human Liver Cell Transcription by Stephen Polyak; (3) Ethanol Alters Dendritic Cell Function In Vivo and Impairs the Subsequent Cellular Immune Responses to Hepatitis C Proteins by Costica Aloman; and (4) Pathogenic Interactions …

Regulation Of Monocyte Il-12 Production: Augmentation By Lymphocyte Contact And Acute Ethanol Treatment, Inhibition By Elevated Intracellular Camp, Gyongyi Szabo, Linda Girouard, Pranoti Mandrekar, Donna Catalano

Gyongyi Szabo

IL-12, a monocyte-derived cytokine, is pivotal in activation of cellular immune response and inflammation. Both inflammatory response and cellular immunity are impaired by acute ethanol consumption. Here, we found that in vitro acute ethanol treatment (25-100 mM) results in a dose-dependent and significant increase of IL-12 in IFN-gamma (100 U/ml) plus Staphylococcal enterotoxin B (SEB; 1 microg/ml) stimulated monocytes and mononuclear cells but not in unstimulated cells from non-alcoholic blood donors. There was significantly greater IL-12 production in the MNC population compared to isolated Mphi (P < 0.001). Prevention of monocyte surface contact with either purified T lymphocytes or monocyte-depleted MNC resulted in a significant, 65+/-20%, decrease in IL-12 production regardless of IFN-gamma, SEB or ethanol stimulation suggesting that Mphi T-cell surface contact provides an additional signal for IL-12 production. In addition to cell surface contact, soluble mediators, particularly IL-10 and PGE2 may regulate IL-12 production. The cyclooxygenase inhibitor, Indomethacin (10(-6)M), augmented both IL-12 and IL-10 levels in isolated monocytes and mononuclear cells whether induced by medium, SEB or SEB plus 25 mM ethanol suggesting that regulation of IL-12 production via the cyclooxygenase pathway is independent of IL-10. Finally, elevation of intracellular cAMP levels by dbcAMP treatment consistently inhibited IL-12 as well as IL-10 production in monocytes induced by IFN-gamma or IFN-gamma plus 25 mM ethanol. These data suggest that augmentation of monocyte IL-12 by acute ethanol is not mediated via the cAMP pathway.

Viral And Host Factors Induce Macrophage Activation And Loss Of Toll-Like Receptor Tolerance In Chronic Hcv Infection, Angela Dolganiuc, Oxana Norkina, Karen Kodys, Donna Catalano, Gennadiy Bakis, Christopher Marshall, Pranoti Mandrekar, Gyongyi Szabo

Gyongyi Szabo

BACKGROUND and AIMS: Persistent inflammation contributes to progression of liver damage in chronic HCV (cHCV) infection. Repeated exposure to toll-like receptor (TLR) ligands results in tolerance, a protective mechanism aimed at limiting inflammation.

METHODS: Monocytes/macrophages were repeatedly stimulated via proinflammatory cytokine-inducing TLRs and evaluated for activation markers.

RESULTS: Unlike monocytes of controls or patients with nonalcoholic steatohepatitis, the monocytes of cHCV patients were hyperresponsive and failed to show homo- or heterotolerance to TLR ligands, manifested by elevated tumor necrosis factor (TNF)-alpha production. Serum levels of interferon (IFN)-gamma, endotoxin (TLR4 ligand), and HCV core protein (TLR2 ligand) were elevated in cHCV …

Down-Regulation Of Tumor Necrosis Factor Alpha Activity By Acute Ethanol Treatment In Human Peripheral Blood Monocytes, Bikash Verma, Miklos Fogarasi, Gyongyi Szabo

Gyongyi Szabo

As the most commonly used drug that can modulate both metabolic and immune pathways, ethanol is evaluated in this report as a regulator of tumor necrosis factor alpha (TNF alpha) production in human peripheral blood monocytes (M phi) in combination with a variety of stimuli. While acute ethanol treatment did not induce TNF alpha in M phi, it was a potent down-regulator of M phi TNF alpha production whether induced by the combination of interferon-gamma plus muramyl dipeptide (MDP) (P < 0.001), lipopolysaccharide (LPS) alone (P < 0.01), or interferon-gamma plus LPS. Down-regulation of M phi TNF alpha by ethanol was dose dependent and statistically significant in the biologically relevant, 25-150 mM, ethanol concentration range. We also demonstrate that these ethanol concentrations did not affect M phi viability. TNF alpha down-regulation by ethanol was most effective when ethanol was administered 4 hr prior to MDP stimulation; however, it was also effective--though to a lesser extent--if it was added at the time of MDP stimulation. Furthermore, ethanol also down-regulated TNF alpha production of the in vivo preactivated M phi of trauma patients, which produce hyperelevated levels of TNF alpha. We have previously shown that the majority of posttrauma elevated M phi TNF alpha is produced by the M phi subpopulation expressing high-affinity type I Fc gamma receptors (Fc gamma RI). When the Fc gamma RI cross-linking-stimulated M phi subpopulation was treated with acute ethanol, TNF alpha production was suppressed again both in in vivo preactivated M phi of trauma patients and in M phi of normal controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Alcohol Consumption Inhibits Accessory Cell Function Of Monocytes And Dendritic Cells, Gyongyi Szabo, Donna Catalano, Bernadette White, Pranoti Mandrekar

Gyongyi Szabo

BACKGROUND: Alcohol affects both innate and acquired immune responses. Chronic alcoholics have reduced delayed-type hypersensitivity response and increased susceptibility to infections. In contrast, recent studies suggest that acute, moderate alcohol consumption has protective effects on mortality. Monocytes and dendritic cells (DC) play a central role in coordination of innate and adaptive immune responses and are pivotal in activation of T lymphocytes in an antigen-specific manner. In this study, we investigated the effects of acute, moderate alcohol consumption on antigen presenting cell function of blood monocytes and monocyte-derived myeloid dendritic cells. METHODS: Accessory cell function of human blood monocytes was tested …

Herbal Product Use By Persons Enrolled In The Hepatitis C Antiviral Long-Term Treatment Against Cirrhosis (Halt-C) Trial, Leonard Seeff, Teresa Curto, Gyongyi Szabo, Gregory Everson, Herbert Bonkovsky, Jules Dienstag, Mitchell Shiffman, Karen Lindsay, Anna Lok, Adrian Di Bisceglie, William Lee, Marc Ghany

Gyongyi Szabo

Herbal products, used for centuries in Far Eastern countries, are gaining popularity in western countries. Surveys indicate that persons with chronic hepatitis C (CHC) often use herbals, especially silymarin (milk thistle extract), hoping to improve the modest response to antiviral therapy and reduce side effects. The Hepatitis C Antiviral Long-Term Treatment Against Cirrhosis (HALT-C) Trial, involving persons with advanced CHC, nonresponders to prior antiviral therapy but still willing to participate in long-term pegylated interferon treatment, offered the opportunity to examine the use and potential effects of silymarin. Among 1145 study participants, 56% had never taken herbals, 21% admitted past use, …

The Role Of Plasmacytoid Dendritic Cell-Derived Ifn Alpha In Antiviral Immunity, Gyongyi Szabo, Angela Dolganiuc

Gyongyi Szabo

Viral infections represent a major source of acute and chronic human disease. The immune system plays a central role in the elimination of viruses through its ability to recognize pathogens and to induce virus-specific cellular activation, accompanied by a robust production of soluble molecules with antiviral effects. Interferons are among the most powerful natural soluble antiviral molecules. Upon viral infection, interferons are produced by a variety of cell types, with immune cells being the main contributors. The immune system works as a well-orchestrated team composed of multiple cell types. The mechanisms of intercellular cooperation that includes dendritic cells (DCs), their …

Ethanol-Mediated Regulation Of Transcription Factors In Immunocompetent Cells, Gyongyi Szabo, Pranoti Mandrekar

Gyongyi Szabo

The immunomodulatory effects of acute and chronic alcohol use are characterized by impaired antigen-specific immune activation and by increased susceptibility to infections due to alterations in innate immune responses and inflammatory mediator production. The central feature of cellular responses to inflammatory and stress signals is the activation of the nuclear regulatory kappa B/Rel family of transcriptional factors via various surface receptor systems in immunocompetent cells. Activation of NF-kappa B, however, is regulated at multiple levels including I-kappa B degradation, nuclear translocation, and by interaction of NF-kappa B/Rel with other transcription factors. Data from our and other laboratories demonstrate that acute …

Microrna Expression Profile In Lieber-Decarli Diet-Induced Alcoholic And Methionine Choline Deficient Diet-Induced Nonalcoholic Steatohepatitis Models In Mice, Angela Dolganiuc, Jan Petrasek, Karen Kodys, Donna Catalano, Pranoti Mandrekar, Arumugam Velayudham, Gyongyi Szabo

Gyongyi Szabo

BACKGROUND: Alcoholic and nonalcoholic steatohepatitis are leading causes of liver diseases worldwide. While of different etiology, these share common pathophysiological mechanisms and feature abnormal fat metabolism, inflammation and fibrosis. MicroRNAs (miRNA) are highly conserved noncoding RNAs that control gene expression at the post-transcriptional level either via the degradation of target mRNAs or the inhibition of translation. Each miRNA controls the expression of multiple targets; miRNAs have been linked to regulation of lipid metabolism and inflammation. METHODS: We fed Lieber-DeCarli alcohol or methionine-choline-deficient (MCD) diets to C57Bl6 and analyzed livers for histopathology, cytokines by ELISA, alanine aminotransferase (ALT) by biochemical assay, …

Selective Induction Of Mononuclear Phagocytes To Produce Neopterin By Interferons, Gabriele Bitterlich, Gyongyi Szabo, Ernst Werner, C. Larcher, Dietmar Fuchs, Arno Hausen, Gilbert Reibnegger, T.F. Schulz, J. Troppmair, Helmut Wachter

Gyongyi Szabo

Interferon-gamma (IFN-gamma) has been shown to be a potent inducer of neopterin secretion by human peripheral blood monocytes/macrophages (1). In this paper, it is shown that other known stimuli of monocytes (e.g., to secrete proteases or to migrate) such as zymosan-activated human serum, lipopolysaccharide, human C3/iC3 and zymosan coated with complement were unable to trigger monocytes/macrophages to release neopterin. Monocytes/macrophages could be stimulated solely by IFN-gamma (25 U/ml) and IFN-alpha at very high concentrations (10,000 U/ml). In the case of human peripheral blood mononuclear cells (PBMNC), basically the same pattern was observed. If however, in the buffer controls PBMNC showed …

Modulation Of Non-Alcoholic Steatohepatitis By Pattern Recognition Receptors In Mice: The Role Of Toll-Like Receptors 2 And 4, Gyongyi Szabo, Arumugam Velayudham, Laszlo Romics, Pranoti Mandrekar

Gyongyi Szabo

Toll-like receptors (TLR) recognize pathogen-derived molecules and induce downstream activation of inflammatory pathways. Fatty liver has been shown to result in increased sensitivity to lipopolysaccharide (LPS), a TLR4 ligand. In this study, we investigated the roles of TLR2 and TLR4 in liver damage and on cytokine induction in a methionine-choline deficient (MCD) diet-induced model of nonalcoholic steatohepatitis. We found that mice with nonalcoholic fatty liver had increased liver injury and inflammatory cytokine induction after challenge with a TLR4 but not with a TLR2 ligand. TLR2 deficient mice were not protected against the development of steatohepatitis after MCD diet feeding. On …

Elevated Monocyte Interleukin-6 (Il-6) Production In Immunosuppressed Trauma Patients. I. Role Of Fc Gamma Ri Cross-Linking Stimulation, Gyongyi Szabo, Karen Kodys, Carol Miller-Graziano

Gyongyi Szabo

This study demonstrates that immunodepressed trauma patients' monocytes produce elevated interleukin-6 to adherence, bacterial, and cytokine stimulation compared to immunocompetent trauma patients' or normals' monocytes, suggesting their in vivo preactivation possibly mediated by the hyperimmunoglobulinemia which characterizes these patients. Furthermore, stimulation of monocytes through cross-linking their Fc gamma RI induces and augments interleukin-6 (IL-6) production to subsequent stimulation both in trauma patients' (P less than 0.001) and in normals' (P less than 0.001) monocytes. As we reported earlier, immunodepressed trauma patients have an increased proportion of Fc gamma RI-bearing monocytes in their total monocyte population and here we show that …

The Critical Role Of Toll-Like Receptor (Tlr) 4 In Alcoholic Liver Disease Is Independent Of The Common Tlr Adapter Myd88, Istvan Hritz, Pranoti Mandrekar, Arumugam Velayudham, Donna Catalano, Angela Dolganiuc, Karen Kodys, Evelyn Kurt-Jones, Gyongyi Szabo

Gyongyi Szabo

The Toll-like receptor 4 (TLR4) that recognizes endotoxin, a trigger of inflammation in alcoholic liver disease (ALD), activates two signaling pathways utilizing different adapter molecules: the common TLR adapter, myeloid differentiation factor 88 (MyD88), or Toll/interleukin immune-response-domain-containing adaptor inducing interferon (IFN)-beta. The MyD88 pathway induces proinflammatory cytokine activation, a critical mediator of ALD. Here we evaluated the role of MyD88 in alcohol-induced liver injury in wild-type, TLR2-deficient, TLR4-deficient, or MyD88-deficient (knockout [KO]) mice after administration of the Lieber-De-Carli diet (4.5% volume/volume ethanol) or an isocaloric liquid control diet for 5 weeks. Alcohol feeding resulted in a significant increase in serum …

Additive Inhibition Of Dendritic Cell Allostimulatory Capacity By Alcohol And Hepatitis C Is Not Restored By Dc Maturation And Involves Abnormal Il-10 And Il-2 Induction, Angela Dolganiuc, Karen Kodys, Andrea Kopasz, Christopher Marshall, Pranoti Mandrekar, Gyongyi Szabo

Gyongyi Szabo

BACKGROUND: Excessive alcohol use results in impaired immunity, and it is associated with increased incidence and progression of chronic hepatitis C virus (HCV) infection. Here we investigated the effects of HCV infection and alcohol on myeloid dendritic cells (DC) that are critical in antiviral immunity.

METHODS: Immature and mature DCs were generated from monocytes of chronic HCV infected patients (HCV-DC) and controls (N-DC) with IL-4 plus granulocyte-macrophage colony stimulating factor (GM-CSF) in the presence or absence of alcohol (25 mM). DC allostimulatory capacity was tested in mixed lymphocyte reaction (MLR) and cytokine production by ELISA.

RESULTS: Allostimulatory capacity of HCV-DCs …

Hepatitis C Virus Ns5a Protein--A Master Regulator, Gyongyi Szabo

Gyongyi Szabo

No abstract provided.

Moderate Alcohol Intake In Humans Attenuates Monocyte Inflammatory Responses: Inhibition Of Nuclear Regulatory Factor Kappa B And Induction Of Interleukin 10, Pranoti Mandrekar, Donna Catalano, Bernadette White, Gyongyi Szabo

Gyongyi Szabo

BACKGROUND: In contrast to the deleterious effects of chronic excessive alcohol consumption on the liver and cardiovascular system, modest alcohol intake, such as 1 to 2 drinks per day, has benefits on cardiovascular mortality. Little is known about the length of time or the amounts of alcohol consumed that may cause alterations in inflammatory cells such as monocytes that are crucial to atherosclerotic vascular disease. Here, we determine in vivo effects of acute alcohol consumption on inflammatory cytokine production and nuclear regulatory factor kappaB (NF-kappaB) binding in human monocytes. METHODS: Human blood monocytes were isolated by plastic adherence before and …

Pathogenic Interactions Between Alcohol And Hepatitis C, Gyongyi Szabo

Gyongyi Szabo

Alcohol is the most commonly abused substance in the United States, and alcohol abuse leads to alcoholic liver disease, a long recognized major public health concern. The high prevalence of chronic hepatitis C virus (HCV) infection, along with the clinical observation that HCV infection is common in alcoholic patients presenting with liver disease, has directed attention to the interaction between alcohol and HCV infection. Clinical studies have identified alcohol use as an independent risk factor for progression of fibrosis in chronic HCV infection. Experimental evidence suggests additive inhibitory effects between HCV and alcohol on antiviral immune responses. In addition, specific …

Acute Ethanol Treatment Modulates Toll-Like Receptor-4 Association With Lipid Rafts, Angela Dolganiuc, Genadyi Bakis, Karen Kodys, Pranoti Mandrekar, Gyongyi Szabo

Gyongyi Szabo

BACKGROUND: Alcohol, a substance that is most frequently abused, suppresses innate immune responses to microbial pathogens. The host senses pathogens via Toll-like receptors (TLRs). Recent studies indicate that alcohol affects TLR signaling. METHODS: Here, we hypothesized that acute alcohol treatment may interfere with early steps of membrane-associated TLR2 and TLR4 signaling at the level of lipid rafts. Human monocytes and Chinese hamster ovary (CHO) cells, transfected with human TLR2, TLR4, or CD14, were stimulated with peptidoglycan (PGN, TLR2 ligand) or lipopolysaccharide (LPS, TLR4 ligand) with or without alcohol (50 mM) and analyzed for cytokine production (enzyme-linked immunosorbent assay), nuclear factor-kappaB …

Induction Of Transforming Growth Factor-Beta And Prostaglandin E2 Production By Ethanol In Human Monocytes, Gyongyi Szabo, Bikash Verma, Miklos Fogarasi, Donna Catalano

Gyongyi Szabo

To test our hypothesis that monocytes (M phi) and their mediators are major contributors to ethanol-related immunodepression, the modulating capacity of acute ethanol treatment was assessed on the production of transforming growth factor-beta (TGF beta) and prostaglandin E2 (PGE2) by human peripheral blood M phi. We demonstrate that acute in vitro treatment of adherent M phi with either 50 or 150 mM ethanol induced a significant increase in the production of TGF beta (P < 0.045 and P < 0.001, respectively). Furthermore, M phi pretreatment with both 50 and 150 mM ethanol augmented TGF beta production in response to subsequent stimulation with …