Life Sciences Commons^™

Inhibition Of Sterile Danger Signals, Uric Acid And Atp, Prevents Inflammasome Activation And Protects From Alcoholic Steatohepatitis In Mice., Arvin Iracheta-Vellve, Jan Petrasek, Abhishek Satishchandran, Benedek Gyongyosi, Banishree Saha, Karen Kodys, Katherine Fitzgerald, Evelyn Kurt-Jones, Gyongyi Szabo

Gyongyi Szabo

Background & Aims: The inflammasome is a well-characterized inducer of inflammation in alcoholic steatohepatitis (ASH). Inflammasome activation requires two signals for mature interleukin (IL)-1β production. Here we asked whether metabolic danger signals trigger inflammasome activation in ASH.

Results:The sterile danger signals, ATP and uric acid, were increased in the serum and liver of alcohol-fed mice. Depletion of uric acid or ATP, or lack of ATP signaling attenuated ASH and prevented inflammasome activation and its major downstream cytokine, IL-1β. Pharmacological depletion of uric acid with allopurinol provided significant protection from alcohol-induced inflammatory response, steatosis and liver damage, and additional protection was …

Metabolic Danger Signals, Uric Acid And Atp, Mediate Inflammatory Cross-Talk Between Hepatocytes And Immune Cells In Alcoholic Liver Disease., Jan Petrasek, Arvin Iracheta-Vellve, Banishree Saha, Abhishek Satishchandran, Karen Kodys, Katherine Fitzgerald, Evelyn Kurt-Jones, Gyongyi Szabo

Gyongyi Szabo

Inflammation defines the progression of ALD from reversible to advanced stages. Translocation of bacterial LPS to the liver from the gut is necessary for alcohol-induced liver inflammation. However, it is not known whether endogenous, metabolic danger signals are required for inflammation in ALD. Uric acid and ATP, 2 major proinflammatory danger signals, were evaluated in the serum of human volunteers exposed to a single dose of ethanol or in supernatants of primary human hepatocytes exposed to ethanol. In vitro studies were used to evaluate the role of uric acid and ATP in inflammatory cross-talk between hepatocytes and immune cells. The …

Alcohol And Hcv: Implications For Liver Cancer, Gyongyi Szabo, Banishree Saha, Terence Bukong

Gyongyi Szabo

Liver cancers are one of the deadliest known malignancies which are increasingly becoming a major public health problem in both developed and developing countries. Overwhelming evidence suggests a strong role of infection with hepatitis B and C virus (HBV and HCV), alcohol abuse, as well as metabolic diseases such as obesity and diabetes either individually or synergistically to cause or exacerbate the development of liver cancers. Although numerous etiologic mechanisms for liver cancer development have been advanced and well characterized, the lack of definite curative treatments means that gaps in knowledge still exist in identifying key molecular mechanisms and pathways …

A Novel Human Radixin Peptide Inhibits Hepatitis C Virus Infection At The Level Of Cell Entry, Terence Bukong, Karen Kodys, Gyongyi Szabo

Gyongyi Szabo

Hepatitis C virus infection of hepatocytes is a multistep process involving the interaction between viral and host cell molecules. Recently, we identified ezrin-moesin-radixin proteins and spleen tyrosine kinase (SYK) as important host therapeutic targets for HCV treatment development. Previously, an ezrin hinge region peptide (Hep1) has been shown to exert anti-HCV properties in vivo, though its mechanism of action remains limited. In search of potential novel inhibitors of HCV infection and their functional mechanism we analyzed the anti-HCV properties of different human derived radixin peptides. Sixteen different radixin peptides were derived, synthesized and tested. Real-time quantitative PCR, cell toxicity assay, …

The Genetics Of Hepatitis C Virus Underlie Its Ability To Escape Humoral Immunity, Jay Kolls, Gyongyi Szabo

Gyongyi Szabo

Hepatitis C virus (HCV) is a leading cause of chronic liver disease, and efforts to develop therapeutic vaccine strategies have been limited by immune escape due to HCV variants that are resistant to current vaccines or HCV variants that rapidly acquire new resistance-conferring mutations. Recently, the crystal structure of the viral envelope protein E2 region was resolved as well as how E2 docks to the host CD81 protein; therefore, antibodies that block this interaction should prevent viral entry into host cells. In this issue of the JCI, Bailey and colleagues show that immune escape of HCV can occur by naturally …

Alcohol-Induced Mir-27a Regulates Differentiation And M2 Macrophage Polarization Of Normal Human Monocytes, Banishree Saha, Johanna Bruneau, Karen Kodys, Gyongyi Szabo

Gyongyi Szabo

Alcohol abuse is a leading cause of liver disease characterized by liver inflammation, fatty liver, alcoholic hepatitis, or liver cirrhosis. Immunomodulatory effects of alcohol on monocytes and macrophages contribute to alcoholic liver disease. Alcohol use, an independent risk factor for progression of hepatitis C virus (HCV) infection-mediated liver disease, impairs host defense and alters cytokine production and monocyte/macrophage activation. We hypothesized that alcohol and HCV have synergistic effects on the phenotype and function of monocytes. Our data show that acute alcohol binge drinking in healthy volunteers results in increased frequency of CD16(+) and CD68(+) and M2-type (CD206(+), dendritic cell [DC]-SIGN(+)-expressing …

Another Armed Cd4(+) T Cell Ready To Battle Hepatocellular Carcinoma, Roniel Cabrera, Gyongyi Szabo

Gyongyi Szabo

No abstract provided.

Human Ezrin-Moesin-Radixin Proteins Modulate Hepatitis C Virus Infection, Terence Bukong, Karen Kodys, Gyongyi Szabo

Gyongyi Szabo

Host cytoskeletal proteins of the ezrin-moesin-radixin (EMR) family have been shown to modulate single-stranded RNA virus infection through regulating stable microtubule formation. Antibody engagement of CD81, a key receptor for hepatitis C virus (HCV) entry, induces ezrin phosphorylation. Here we tested the role of EMR proteins in regulating HCV infection and explored potential therapeutic targets. We show that HCV E2 protein induces rapid ezrin phosphorylation and its cellular redistribution with F-actin by way of spleen tyrosine kinase (SYK). Therapeutically blocking the functional roles of SYK or F-actin reorganization significantly reduced Huh7.5 cell susceptibility to HCV J6/JFH-1 infection. Using gene regulation, …

Differences In Innate Immune Signaling Between Alcoholic And Non-Alcoholic Steatohepatitis, Jan Petrasek, Timea Csak, Michal Ganz, Gyongyi Szabo

Gyongyi Szabo

The similar histopathological characteristics of alcoholic steatohepatitis (ASH) and non-alcoholic steatohepatitis (NASH), and the crucial role of the innate immune response in both conditions may lead to the assumption that ASH and NASH represent the same pathophysiological entities caused by different risk factors. In this review paper, we elaborate on the pathophysiological differences between these two entities and highlight the disease-specific involvement of signaling molecules downstream of the Toll-like receptor 4, and the differential mechanism by which the inflammasome contributes to ASH versus NASH. Our findings emphasize that ASH and NASH have disease-specific mechanisms and therefore represent distinct biological entities. …

Micro-Rna-155 Deficiency Prevents Alcohol-Induced Serum Endotoxin Increase And Small Bowel Inflammation In Mice, Dora Lippai, Shashi Bala, Donna Catalano, Karen Kodys, Gyongyi Szabo

Gyongyi Szabo

BACKGROUND: Chronic alcohol impairs gut barrier function and induces inflammatory cytokines. The effects of acute alcohol binge on the gut are partially understood. Micro-RNA-155 (miR-155), a modulator of cytokine and T-cell immune response in the gut, stabilizes tumor necrosis factor-alpha (TNFalpha) mRNA. Here, we investigated the role of the inflammation modulator miR-155 as well as the effects of acute binge and chronic alcohol feeding in the small bowel (SB) in mice. METHODS: For the acute alcohol binge, wild-type (WT) mice received 5 g/kg 50% alcohol/d or equal amount of water oral gavage for 3 days. WT and miR-155-deficient (miR-155-knockout [KO]) …

Human Type 2 Myeloid Dendritic Cells Produce Interferon-Lambda And Amplify Interferon-Alpha In Response To Hepatitis C Virus Infection, Shuye Zhang, Karen Kodys, Kui Li, Gyongyi Szabo

Gyongyi Szabo

BACKGROUND and AIMS: The type III interferons (IFN-lambdas: interleukin [IL]-28a, IL-28b, and IL-29) have important roles in hepatitis C virus (HCV) infection, but little is understood about what cells produce these cytokines or how production is activated. We investigated whether human immune cells recognize HCV-infected cells and respond by producing IFN-lambda. METHODS: We cultured healthy human peripheral blood mononuclear cells (PBMCs) with different populations of immune cells and Japanese fulminant hepatitis-1 (JFH-1) HCV-infected Huh7.5 (cell culture-derived HCV particles [HCVcc]/Huh7.5) cells. RESULTS: Human PBMCs recognized HCVcc/Huh7.5 cells and responded by producing IFN-alpha, IFN-gamma, and IFN-lambda. A rare subset of myeloid dendritic …

Converging Actions Of Alcohol On Liver And Brain Immune Signaling, Gyongyi Szabo, Dora Lippai

Gyongyi Szabo

Chronic excessive alcohol consumption results in inflammation in multiple organs, including the brain. While the contribution of neuroinflammation to alcohol-related cognitive dysfunction and behavioral alterations is established, the mechanisms by which alcohol triggers inflammation in the brain are only partially understood. There are acute and long-term alterations in brain function due to intercellular and intracellular changes of different cell types as a result of alcohol consumption. This review focuses on the alcohol-induced proinflammatory cellular and molecular changes in the central nervous system. Alcohol passes through the blood-brain barrier and alters neurotransmission. Alcohol use activates microglia and astrocyte, contributing to neurodegeneration …

Both Bone Marrow-Derived And Non-Bone Marrow-Derived Cells Contribute To Aim2 And Nlrp3 Inflammasome Activation In A Myd88-Dependent Manner In Dietary Steatohepatitis, Timea Csak, Arun Pillai, Michal Ganz, Dora Lippai, Jan Petrasek, Jin-Kyu Park, Karen Kodys, Angela Dolganiuc, Evelyn Kurt-Jones, Gyongyi Szabo

Gyongyi Szabo

BACKGROUND and AIMS: Inflammation promotes the progression of non-alcoholic steatohepatitis (NASH). Toll-like receptor 4 (TLR4) and TLR9 activation through myeloid differentiation primary response gene 88 (MyD88) and production of mature interleukin-1beta (IL-1beta) via inflammasome activation contribute to steatohepatitis. Here, we investigated the inter-relationship between TLR signalling and inflammasome activation in dietary steatohepatitis.

METHODS: Wild type (WT), TLR4- and MyD88-deficient (KO) mice received methionine-choline-deficient (MCD) or -supplemented (MCS) diets for 5 weeks and a subset was challenged with TLR9 ligand CpG-DNA.

RESULTS: TLR4, TLR9, AIM2 (absent in melanoma 2) and NLRP3 (NLR family pyrin domain containing 3) inflammasome mRNA, and mature …

Toll-Like Receptors In Liver Disease, Jan Petrasek, Timea Csak, Gyongyi Szabo

Gyongyi Szabo

Activation of inflammatory signaling pathways is of central importance in the pathogenesis of alcoholic liver disease (ALD) and nonalcoholic steatohepatitis (NASH). Recent studies demonstrated that Toll-like receptors, the sensors of microbial and endogenous danger signals, are expressed and activated in innate immune cells as well as in parenchymal cells in the liver and thereby contribute to ALD and NASH. In this review, we emphasize the importance of gut-derived endotoxin and its recognition by TLR4 in the liver. The significance of TLR-induced intracellular signaling pathways and cytokine production as well as the contribution of individual cell types to the inflammation is …

Exosome-Mediated Delivery Of Functionally Active Mirna-155 Inhibitor To Macrophages, Fatemeh Momen-Heravi, Shashi Bala, Terence Bukong, Gyongyi Szabo

Gyongyi Szabo

Exosomes, membranous nanovesicles, naturally carry bio-macromolecules and play pivotal roles in both physiological intercellular crosstalk and disease pathogenesis. Here, we showed that B cell-derived exosomes can function as vehicles to deliver exogenous miRNA-155 mimic or inhibitor into hepatocytes or macrophages, respectively. Stimulation of B cells significantly increased exosome production. Unlike in parental cells, baseline level of miRNA-155 was very low in exosomes derived from stimulated B cells. Exosomes loaded with a miRNA-155 mimic significantly increased miRNA-155 levels in primary mouse hepatocytes and the liver of miRNA-155 knockout mice. Treatment of RAW macrophages with miRNA-155 inhibitor loaded exosomes resulted in statistically …

Immune And Inflammatory Pathways In Nash, Michal Ganz, Gyongyi Szabo

Gyongyi Szabo

Immune and inflammatory pathways have a central role in the pathogenesis of non-alcoholic fatty liver disease (NAFLD). Both the innate and adaptive immune systems contribute to the development of NAFLD. Pathogen-associated molecular patterns and danger-associated molecular patterns are known to activate a variety of pattern-recognition receptors that result in inflammation. The key features of the immune system and inflammatory pathways in the development of NAFLD are discussed in this review.

Innate Immune Cell Networking In Hepatitis C Virus Infection, Banishree Saha, Gyongyi Szabo

Gyongyi Szabo

Persistent viral infection, such as HCV infection, is the result of the inability of the host immune system to mount a successful antiviral response, as well as the escape strategies devised by the virus. Although each individual component of the host immune system plays important roles in antiviral immunity, the interactive network of immune cells as a whole acts against the virus. The innate immune system forms the first line of host defense against viral infection, and thus, virus elimination or chronic HCV infection is linked to the direct outcome of the interactions between the various innate immune cells and …

Alcohol Facilitates Hcv Rna Replication Via Up-Regulation Of Mir-122 Expression And Inhibition Of Cyclin G1 In Human Hepatoma Cells, Wei Hou, Terence Bukong, Karen Kodys, Gyongyi Szabo

Gyongyi Szabo

BACKGROUND: Clinical studies demonstrate synergistic liver damage by alcohol and hepatitis C virus (HCV); however, the mechanisms by which alcohol promotes HCV infection remain obscure. The liver-specific microRNA-122 (miR-122) regulates HCV replication and expression of host genes, including Cyclin G1. Here, we hypothesized that alcohol regulates miR-122 expression and thereby modulates HCV RNA replication. METHODS: The J6/JFH/Huh-7.5 model of HCV infection was used in this study. Real-time quantitative polymerase chain reaction, Western blotting, electrophoretic mobility shift assay, and confocal microscopy were used for experimental analysis. RESULTS: We found that acute alcohol exposure (25 mM) significantly increased intracellular HCV RNA as …

Ifn-Gamma Production By Human Natural Killer Cells In Response To Hcv-Infected Hepatoma Cells Is Dependent On Accessory Cells, Shuye Zhang, Banishree Saha, Karen Kodys, Gyongyi Szabo

Gyongyi Szabo

BACKGROUND and AIMS: Interferon-gamma (IFN-gamma), a cytokine produced by activated natural killer cell (NK) and T lymphocytes, is an important regulator of innate and adaptive immunity during hepatitis C virus (HCV) infection. However, the cellular sources and mechanisms of IFN-gamma induction in HCV-infection are not fully understood. METHODS: We cultured normal human peripheral blood mononuclear cells (PBMCs) with different populations of immune cells and JFH-1 HCV-infected Huh7.5 (JFH-1/Huh7.5) cells. RESULTS: We found that PBMCs produced large amounts of IFN-gamma after co-culture with JFH-1/Huh7.5 cells. Using intracellular cytokine staining we confirmed that NK cells and NKT cells (to a lesser extent) …

Human Monoclonal Antibody Mbl-Hcv1 Delays Hcv Viral Rebound Following Liver Transplantation: A Randomized Controlled Study, R. Chung, F. Gordon, M. Curry, T. Schiano, S. Emre, K. Corey, J. Markmann, M. Hertl, J. Pomposelli, E. Pomfret, S. Florman, M. Schilsky, Teresa Broering, Robert Finberg, Gyongyi Szabo, Phillip Zamore, U. Khettry, Gregory Babcock, Donna Ambrosino, Brett Leav, Mark Leney, H. Smith, Deborah Molrine

Gyongyi Szabo

Rapid allograft infection complicates liver transplantation (LT) in patients with hepatitis C virus (HCV). Pegylated interferon-alpha and ribavirin therapy after LT has significant toxicity and limited efficacy. The effect of a human monoclonal antibody targeting the HCV E2 glycoprotein (MBL-HCV1) on viral clearance was examined in a randomized, double-blind, placebo-controlled pilot study in patients infected with HCV genotype 1a undergoing LT. Subjects received 11 infusions of 50 mg/kg MBL-HCV1 (n=6) or placebo (n=5) intravenously with three infusions on day of transplant, a single infusion on days 1 through 7 and one infusion on day 14 after LT. MBL-HCV1 was well-tolerated …

Type Iii Interferons, Il-28 And Il-29, Are Increased In Chronic Hcv Infection And Induce Myeloid Dendritic Cell-Mediated Foxp3+ Regulatory T Cells, Angela Dolganiuc, Karen Kodys, Christopher Marshall, Banishree Saha, Shuye Zhang, Shashi Bala, Gyongyi Szabo

Gyongyi Szabo

BACKGROUND AND AIMS: Hepatitis C virus (HCV) is difficult to eradicate and type III interferons (IFN-lambda, composed of IL-28A, IL-28B and IL-29) are novel therapeutic candidates. We hypothesized that IFN-lambda have immunomodulatory effects in HCV- infected individuals. MATERIALS AND METHODS: We analyzed the expression of IFN-lambda and its receptor (composed of IL-10R2 and IFN-lambdaR subunits) in the blood and livers of patients with chronic (c)HCV infection compared to controls (those who cleared HCV by sustained virological response, SVR, and those with liver inflammation of non-viral origin, non-alcoholic steatohepatitis, NASH). We also compared the proliferative capacity of dendritic cells (DCs) obtained …

Dendritic Cells In Hepatitis C Infection: Can They (Help) Win The Battle, Angela Dolganiuc, Gyongyi Szabo

Gyongyi Szabo

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 …

Inflammasomes In Liver Diseases, Gyongyi Szabo, Timea Csak

Gyongyi Szabo

Inflammation is a common element in the pathogenesis of most chronic liver diseases that lead to fibrosis and cirrhosis. Inflammation is characterized by activation of innate immune cells and production of pro-inflammatory cytokines IL-1alpha, IL-1beta, and TNFalpha. Inflammasomes are intracellular multiprotein complexes expressed in both parenchymal and non-parenchymal cells of the liver that in response to cellular danger signals activate caspase-1, and release IL-1beta and IL-18. The importance of inflammasome activation in various forms of liver diseases in relation to liver damage, steatosis, inflammation and fibrosis is discussed in this review. Elsevier B.V. All rights reserved.

Hypoxia And Hypoxia Inducible Factors: Diverse Roles In Liver Diseases, Bharath Nath, Gyongyi Szabo

Gyongyi Szabo

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 …

Mitochondrial Antiviral Signaling Protein Defect Links Impaired Antiviral Response And Liver Injury In Steatohepatitis In Mice, Timea Csak, Angela Dolganiuc, Karen Kodys, Bharath Nath, Jan Petrasek, Shashi Bala, Dora Lippai, Gyongyi Szabo

Gyongyi Szabo

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 …

An Essential Role For Monocyte Chemoattractant Protein-1 In Alcoholic Liver Injury: Regulation Of Proinflammatory Cytokines And Hepatic Steatosis In Mice, Pranoti Mandrekar, Aditya Ambade, Arlene Lim, Gyongyi Szabo, Donna Catalano

Gyongyi Szabo

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 …

Cd81/Cd9 Tetraspanins Aid Plasmacytoid Dendritic Cells In Recognition Of Hcv-Infected Cells And Induction Of Ifnalpha, Shuye Zhang, Karen Kodys, Gregory Babcock, Gyongyi Szabo

Gyongyi Szabo

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 …

Fatty Acid And Endotoxin Activate Inflammasomes In Mouse Hepatocytes That Release Danger Signals To Stimulate Immune Cells, Timea Csak, Michal Ganz, Justin Pespisa, Karen Kodys, Angela Dolganiuc, Gyongyi Szabo

Gyongyi Szabo

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 …

Aberrations In Post-Trauma Monocyte (Mo) Subpopulation: Role In Septic Shock Syndrome, Carol Miller-Graziano, Gyongyi Szabo, Karen Kodys, Katherine Griffey

Gyongyi Szabo

Appearance of increased proportions of monocytes bearing the 72kd(FcRI) receptor for IgG correlated to aberrant monocyte (MO) functions, depressed immune functions, and poor clinical outcome. The trauma patients' FcRI+ MO subpopulation produced the majority of their elevated IL-6, TNF alpha, TGF beta, and PGE2. IgG stimulation of patients' MO through FcRI not only stimulated TNF alpha, IL-6, and PGE2 levels, but also greatly augmented the levels of these monokines produced after subsequent bacterial challenge. Post-trauma increased IL-6 levels can lead to polyclonal B-cell activation and high levels of circulating, nonspecific IgG as seen in trauma patients. This nonspecific IgG triggers …

Critical Role Of Toll-Like Receptors And The Common Tlr Adaptor, Myd88, In Induction Of Granulomas And Liver Injury, Arumugam Velayudham, Istvan Hritz, Angela Dolganiuc, Pranoti Mandrekar, Evelyn Kurt-Jones, Gyongyi Szabo

Gyongyi Szabo

BACKGROUND/AIMS: Toll-like receptors (TLR) recognize pathogens and regulate innate immune activation. Here, we investigated the roles of TLR9 and the common TLR adaptor, MyD88, in liver injury.

METHODS: C57BL6, TLR9(-/-), IFNgamma(-/-) or MyD88(-/-) mice were primed with Propionibacterium acnes, TLR9 (CpG) or TLR2 (lipoteichoic acid) ligands followed by LPS challenge. ALT, cytokines and liver histology were assessed.

RESULTS: Selective priming through TLR9 but not TLR2 induced granulomas, elevated serum ALT, and sensitized C57BL6 mice to increased LPS-induced serum IL-6, IL-12 and IFNgamma levels. Further, TLR2 and TLR9 ligands synergized in induction of granulomas and sensitization to LPS-induced inflammation. IFNgamma induction …