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1.
PLoS One ; 12(2): e0169310, 2017.
Article in English | MEDLINE | ID: mdl-28146577

ABSTRACT

BACKGROUND: Recently, a complex microbiome was comprehensibly characterized in the serum and ascitic fluid of cirrhotic patients. In the current study, we investigated for the first time the induction of inflammatory pathways and Nitric Oxide, as well as the systemic hemodynamics in conjunction with the blood microbiome in a Child-Pugh class B cirrhotic cohort. METHODS AND FINDINGS: We used the Intestinal Infections Microbial DNA qPCR Array to screen for 53 bacterial DNA from the gut in the blood. Assays were designed using the 16S rRNA gene as a target, and PCR amplification primers (based on the Human Microbiome Project) and hydrolysis-probe detection. Eighteen systemic hemodynamic parameters were measured non-invasively by impedance cardiography using the BioZ ICG monitor. The inflammatory response was assessed by measuring blood cytokines, Nitric Oxide RNA arrays, and Nitric Oxide. In the blood of this cirrhotic cohort, we detected 19 of 53 bacterial species tested. The number of bacterial species was markedly increased in the blood of cirrhotic patients compared to control individuals (0.2+/-0.4 vs 3.1+/-2.3; 95% CI: 1.3 to 4.9; P = 0.0030). The total bacterial DNA was also increased in the blood of cirrhotic subjects compared to control subjects (0.2+/- 1.1 vs 41.8+/-132.1; 95% CI: 6.0 to 77.2; P = 0.0022). In the cirrhotic cohort, the Cardiac Output increased by 37% and the Systemic Vascular Resistance decreased by 40% (P< 0.00001 for both compared to control subjects). Systemic Vascular Resistance was inversely correlated to blood bacterial DNA quantity (- 0.621; 95% CI -0.843 to -0.218; P = 0.0060), blood bacterial species number (- 0.593; 95% CI -0.83 to -0.175; P = 0.0095; logistic regression: Chi Square = 5.8877; P = 0.0152), and serum Nitric Oxide (- 0.705; 95% CI -0.881 to -0.355; P = 0.0011). Many members of the Nitric Oxide signaling pathway gene family were increased in cirrhotic subjects. CONCLUSIONS: Our study identified blood bacterial DNA in ~ 90% of the cirrhotic patients without clinical evidences of infection, and suggests that the quantity of bacterial DNA in blood may stimulate signaling pathways, including Nitric Oxide, that could decrease systemic vascular resistance and increase cardiac output.


Subject(s)
Hemodynamics , Liver Cirrhosis/complications , Liver Cirrhosis/physiopathology , Microbiota , Sepsis/etiology , Aged , Bacteria/classification , Bacteria/genetics , Biomarkers , Case-Control Studies , Cytokines/genetics , Cytokines/metabolism , Gastrointestinal Microbiome , Gene Expression Regulation , Humans , Liver Cirrhosis/diagnosis , Liver Cirrhosis/etiology , Liver Function Tests , Macrophages/immunology , Macrophages/metabolism , Male , Metagenome , Metagenomics/methods , Middle Aged , NLR Family, Pyrin Domain-Containing 3 Protein/metabolism , Nitric Oxide/metabolism
2.
Sci Rep ; 6: 24268, 2016 Apr 12.
Article in English | MEDLINE | ID: mdl-27067260

ABSTRACT

Amplification of liver injury is mediated by macrophages but the signaling by which the macrophage inflammasome enhances liver injury is not completely understood. The CCAAT/Enhancer Binding Protein-ß (C/EBPß) is a critical signaling molecule for macrophages because expression of a dominant inhibitor of C/EBPß DNA-binding sites or a targeted deletion of C/EBPß results in impaired macrophage differentiation. We reported that expression of the phosphorylation-mutant C/EBPß-Glu217, which mimics phosphorylated C/EBPß-Thr217, was sufficient to confer macrophage survival to Anthrax lethal toxin. Here, using primary hepatocytes, primary liver macrophages, dominant positive and negative transgenic mice of the C/EBPß-Thr217 phosphoacceptor, macrophage ablation, and an inhibitory peptide of C/EBPß-Thr217 phosphorylation, we determined that this phosphorylation is essential for the activation of the inflammasome in liver macrophages and for the hepatocyte apoptosis induced by hepatotoxins that results in liver injury. Similar findings were observed in the livers of patients with acute injury induced by Toxic Oil Syndrome.


Subject(s)
CCAAT-Enhancer-Binding Protein-beta/metabolism , Inflammasomes/metabolism , Liver/pathology , Macrophages/immunology , Protein Processing, Post-Translational , Animals , Apoptosis , Cells, Cultured , Hepatocytes/physiology , Humans , Mice, Transgenic , Phosphorylation
3.
Gastroenterology ; 147(2): 377-84.e1, 2014 Aug.
Article in English | MEDLINE | ID: mdl-24818764

ABSTRACT

BACKGROUND & AIMS: n-3 polyunsaturated fatty acids reduce insulin resistance, lipogenesis, and inflammation, which are features of nonalcoholic steatohepatitis (NASH). Ethyl-eicosapentanoic acid (EPA-E) is a synthetic polyunsaturated fatty acid that reduces hypertriglyceridemia. We report the final results of a phase 2b multicenter, prospective, double-blind, randomized, placebo-controlled trial of EPA-E for NASH. METHODS: Our study, performed at 37 sites in North America, included subjects with NASH and nonalcoholic fatty liver disease (NAFLD) activity scores ≥ 4, with minimum scores of 1 for steatosis and inflammation, along with either ballooning or at least stage 1a fibrosis. A total of 243 subjects were randomly assigned to groups given placebo (n = 75), low-dosage EPA-E (1800 mg/d; n = 82), or high-dosage EPA-E (2700 mg/d; n = 86) for 12 months. Subjects were examined at 4-week intervals for 3 months, 6-week intervals for the next 3 months, and every 3 months thereafter, until 1 month after the last dose was taken. Liver biopsies were collected 2 weeks after the last dose of EPA-E or placebo. The primary efficacy end point was NAFLD activity score ≤ 3, without worsening of fibrosis; or a decrease in NAFLD activity score by ≥ 2 with contribution from >1 parameter, without worsening of fibrosis, 1 year after the last dose of EPA-E or placebo was given. RESULTS: Similar proportions of subjects in each group met the primary end point (40%, 37%, and 35.9% for placebo, low-dosage, and high-dosage EPA-E, respectively). EPA-E had no significant effects on steatosis, inflammation, ballooning, or fibrosis scores. There were no significant effects on levels of liver enzymes, insulin resistance, adiponectin, keratin 18, high-sensitivity C-reactive protein, or hyaluronic acid. High-dosage EPA-E reduced levels of triglyceride (-6.5 mg/dL vs an increase of 12 mg/dL in the placebo group; P = .03). There were no treatment-related serious adverse events. CONCLUSIONS: In a phase 2 trial, EPA-E had no significant effect on the histologic features of NASH. EPA-E reduced subjects' levels of triglyceride compared with placebo, without any increase in serious adverse events. Clinicaltrials.gov Number: 01154985.


Subject(s)
Eicosapentaenoic Acid/analogs & derivatives , Fatty Liver/drug therapy , Liver/drug effects , Biopsy , Disease Progression , Double-Blind Method , Eicosapentaenoic Acid/adverse effects , Eicosapentaenoic Acid/therapeutic use , Fatty Liver/complications , Fatty Liver/pathology , Female , Humans , Liver/pathology , Liver Cirrhosis/drug therapy , Liver Cirrhosis/etiology , Liver Cirrhosis/pathology , Male , Middle Aged , Non-alcoholic Fatty Liver Disease , North America , Prospective Studies , Severity of Illness Index , Time Factors , Treatment Failure
4.
N Engl J Med ; 370(20): 1879-88, 2014 May 15.
Article in English | MEDLINE | ID: mdl-24720702

ABSTRACT

BACKGROUND: High rates of sustained virologic response were observed among patients with hepatitis C virus (HCV) infection who received 12 weeks of treatment with the nucleotide polymerase inhibitor sofosbuvir combined with the NS5A inhibitor ledipasvir. This study examined 8 weeks of treatment with this regimen. METHODS: In this phase 3, open-label study, we randomly assigned 647 previously untreated patients with HCV genotype 1 infection without cirrhosis to receive ledipasvir and sofosbuvir (ledipasvir-sofosbuvir) for 8 weeks, ledipasvir-sofosbuvir plus ribavirin for 8 weeks, or ledipasvir-sofosbuvir for 12 weeks. The primary end point was sustained virologic response at 12 weeks after the end of therapy. RESULTS: The rate of sustained virologic response was 94% (95% confidence interval [CI], 90 to 97) with 8 weeks of ledipasvir-sofosbuvir, 93% (95% CI, 89 to 96) with 8 weeks of ledipasvir-sofosbuvir plus ribavirin, and 95% (95% CI, 92 to 98) with 12 weeks of ledipasvir-sofosbuvir. As compared with the rate of sustained virologic response in the group that received 8 weeks of ledipasvir-sofosbuvir, the rate in the 12-week group was 1 percentage point higher (97.5% CI, -4 to 6) and the rate in the group that received 8 weeks of ledipasvir-sofosbuvir with ribavirin was 1 percentage point lower (95% CI, -6 to 4); these results indicated noninferiority of the 8-week ledipasvir-sofosbuvir regimen, on the basis of a noninferiority margin of 12 percentage points. Adverse events were more common in the group that received ribavirin than in the other two groups. No patient who received 8 weeks of only ledipasvir-sofosbuvir discontinued treatment owing to adverse events. CONCLUSIONS: Ledipasvir-sofosbuvir for 8 weeks was associated with a high rate of sustained virologic response among previously untreated patients with HCV genotype 1 infection without cirrhosis. No additional benefit was associated with the inclusion of ribavirin in the regimen or with extension of the duration of treatment to 12 weeks. (Funded by Gilead Sciences; ION-3 ClinicalTrials.gov number, NCT01851330.).


Subject(s)
Antiviral Agents/therapeutic use , Benzimidazoles/therapeutic use , Fluorenes/therapeutic use , Hepatitis C, Chronic/drug therapy , Uridine Monophosphate/analogs & derivatives , Adult , Aged , Antiviral Agents/adverse effects , Benzimidazoles/adverse effects , Drug Administration Schedule , Drug Resistance, Viral , Drug Therapy, Combination , Female , Fluorenes/adverse effects , Genotype , Hepacivirus/genetics , Hepatitis C, Chronic/virology , Humans , Male , Middle Aged , RNA, Viral/blood , Ribavirin/adverse effects , Ribavirin/therapeutic use , Sofosbuvir , Uridine Monophosphate/adverse effects , Uridine Monophosphate/therapeutic use , Viral Load , Young Adult
5.
N Engl J Med ; 370(20): 1889-98, 2014 May 15.
Article in English | MEDLINE | ID: mdl-24725239

ABSTRACT

BACKGROUND: In phase 2 studies, treatment with the all-oral combination of the nucleotide polymerase inhibitor sofosbuvir and the NS5A inhibitor ledipasvir resulted in high rates of sustained virologic response among previously untreated patients with hepatitis C virus (HCV) genotype 1 infection. METHODS: We conducted a phase 3, open-label study involving previously untreated patients with chronic HCV genotype 1 infection. Patients were randomly assigned in a 1:1:1:1 ratio to receive ledipasvir and sofosbuvir in a fixed-dose combination tablet once daily for 12 weeks, ledipasvir-sofosbuvir plus ribavirin for 12 weeks, ledipasvir-sofosbuvir for 24 weeks, or ledipasvir-sofosbuvir plus ribavirin for 24 weeks. The primary end point was a sustained virologic response at 12 weeks after the end of therapy. RESULTS: Of the 865 patients who underwent randomization and were treated, 16% had cirrhosis, 12% were black, and 67% had HCV genotype 1a infection. The rates of sustained virologic response were 99% (95% confidence interval [CI], 96 to 100) in the group that received 12 weeks of ledipasvir-sofosbuvir; 97% (95% CI, 94 to 99) in the group that received 12 weeks of ledipasvir-sofosbuvir plus ribavirin; 98% (95% CI, 95 to 99) in the group that received 24 weeks of ledipasvir-sofosbuvir; and 99% (95% CI, 97 to 100) in the group that received 24 weeks of ledipasvir-sofosbuvir plus ribavirin. No patient in either 12-week group discontinued ledipasvir-sofosbuvir owing to an adverse event. The most common adverse events were fatigue, headache, insomnia, and nausea. CONCLUSIONS: Once-daily ledipasvir-sofosbuvir with or without ribavirin for 12 or 24 weeks was highly effective in previously untreated patients with HCV genotype 1 infection. (Funded by Gilead Sciences; ION-1 ClinicalTrials.gov number NCT01701401.).


Subject(s)
Antiviral Agents/therapeutic use , Benzimidazoles/therapeutic use , Fluorenes/therapeutic use , Hepacivirus/genetics , Hepatitis C, Chronic/drug therapy , Uridine Monophosphate/analogs & derivatives , Adolescent , Adult , Aged , Aged, 80 and over , Antiviral Agents/adverse effects , Benzimidazoles/adverse effects , Drug Administration Schedule , Drug Resistance, Viral , Drug Therapy, Combination , Female , Fluorenes/adverse effects , Genotype , Hepatitis C, Chronic/virology , Humans , Male , Middle Aged , RNA, Viral/blood , Ribavirin/adverse effects , Ribavirin/therapeutic use , Sofosbuvir , Uridine Monophosphate/adverse effects , Uridine Monophosphate/therapeutic use , Viral Load , Young Adult
6.
Hepatology ; 59(3): 1052-9, 2014 Mar.
Article in English | MEDLINE | ID: mdl-24115225

ABSTRACT

UNLABELLED: The rationale for screening inflammatory serum biomarkers of the hepatic vein pressure gradient (HVPG) is based on the fact that portal hypertension is pathogenically related to liver injury and fibrosis, and that in turn these are associated with the activation of inflammatory pathways. This was a nested cohort study in the setting of a randomized, clinical trial to assess the development of gastroesophageal varices (GEV) (N Engl J Med 2005;353:2254). Patients had cirrhosis and portal hypertension but did not have GEV. A total of 90 patients who had baseline day-1 sera available were enrolled in the present study. The objective of this study was to determine whether inflammatory biomarkers in conjunction with clinical parameters could be used to develop a predictive paradigm for HVPG. The correlations between HVPG and interleukin (IL)-1ß (P=0.0052); IL-1R-α (P=0.0085); Fas-R (P=0.0354), and serum VCAM-1 (P=0.0007) were highly significant. By using multivariate logistic regression analysis and selected parameters (transforming growth factor beta [TGFß]; heat shock protein [HSP]-70; at-risk alcohol use; and Child class B) we could exclude HVPG ≥ 12 mmHg with 86% accuracy (95% confidence interval [CI]: 67.78 to 96.16%) and the sensitivity was 87.01% (95% CI: 69.68 to 96.34%). Therefore, the composite test could identify 86% of compensated cirrhosis patients with HVPG below 12 mmHg and prevent unnecessary esophagogastroduodenoscopy with its associated morbidity and costs in these patients. Our diagnostic test was not efficient in predicting HVPG ≥ 12 mmHg. CONCLUSION: A blood test for HVPG could be performed in cirrhosis patients to prevent unnecessary esophagogastroduodenoscopy.


Subject(s)
Adrenergic beta-Antagonists/therapeutic use , Esophageal and Gastric Varices/prevention & control , Hypertension, Portal/immunology , Hypertension, Portal/metabolism , Liver Cirrhosis/immunology , Liver Cirrhosis/metabolism , Adult , Aged , Biomarkers/blood , Cohort Studies , Esophageal and Gastric Varices/immunology , Esophageal and Gastric Varices/metabolism , Female , Hepatic Veins/physiopathology , Hepatitis, Chronic/immunology , Hepatitis, Chronic/metabolism , Hepatitis, Chronic/physiopathology , Humans , Hypertension, Portal/physiopathology , Liver Cirrhosis/physiopathology , Logistic Models , Male , Middle Aged , Portal Pressure/physiology , Prospective Studies , Sensitivity and Specificity
7.
PLoS One ; 7(3): e31516, 2012.
Article in English | MEDLINE | ID: mdl-22412837

ABSTRACT

BACKGROUND: Insulin resistance (IR) is induced by chronic hepatitis C virus (HCV) genotypes 1 and 4 infections. It is not known whether drugs that affect IR such as Pioglitazone and Prednisone also affect serum HCV RNA titers independently of PEG-Interferon-α2/ribavirin treatment. The primary aim was to assess whether Pioglitazone by improving IR and/or inflammation decreases HCV viral load independently of standard of care HCV treatment. A secondary aim was to assess whether Prednisone, a drug that induces insulin resistance and stimulates HCV viral entry and replication in replicon culture systems, increases HCV viral load in this population. METHODOLOGY/PRINCIPAL FINDINGS: We designed a two-arm, parallel Pilot Study of overweight, treatment naïve genotype 4 HCV-infected patients at a public referral Liver Clinic in Giza, Egypt. The subjects received Pioglitazone (30 mg/day for 14 days) or Prednisone (40 mg/day for 4 days) in a randomized fashion, but the two arms can be considered independent pilot studies. Only changes from baseline within each arm were assessed and no contrasts of the interventions were made, as this was not an aim of the study. Among 105 consecutive HCV genotype 4 patients, 39 were enrolled based on the optimal sample size and power analysis according to the CONSORT statement; 20 to the Pioglitazone group and 19 to the Prednisone group. Pioglitazone was effective in decreasing serum HCV RNA at day-14 (n = 10; difference of means = 205,618 IU/ml; 95% CI 26,600 to 384,600; P<0.001). Although Prednisone did increase serum HCV RNA at day-4 (n = 10; change from baseline = -42,786 IU/ml; 95% CI -85,500 to -15,700; P = 0.049), the log(10) HCV RNA titers were statistically not different from baseline day-0. CONCLUSION/SIGNIFICANCE: This is the first documentation that Pioglitazone decreases the serum HCV RNA titers independently of PEG-Interferon-α2/ribavirin treatment. The novel findings of our Study provide the foundation for basic and clinical investigations on the molecular mechanisms responsible for the Pioglitazone-induced decrease in HCV genotype 4 RNA titers. TRIAL REGISTRATION: ClinicalTrials.gov NCT01157975.


Subject(s)
Antiviral Agents/therapeutic use , Hepacivirus/genetics , Hepatitis C, Chronic/drug therapy , Thiazolidinediones/therapeutic use , Adult , Antiviral Agents/adverse effects , Blood Glucose/drug effects , Chemical and Drug Induced Liver Injury/metabolism , Cytokines/blood , Female , Genotype , Hepacivirus/drug effects , Hepatitis C, Chronic/virology , Humans , Insulin Resistance , Male , Middle Aged , Overweight , Pilot Projects , Pioglitazone , Prednisolone/pharmacology , Thiazolidinediones/adverse effects , Treatment Outcome , Viral Load/drug effects
8.
Hepatology ; 55(2): 419-28, 2012 Feb.
Article in English | MEDLINE | ID: mdl-22006541

ABSTRACT

UNLABELLED: In nonalcoholic steatohepatitis (NASH), the extent of hepatocyte apoptosis correlates with disease severity. Reducing hepatocyte apoptosis with the selective caspase inhibitor GS-9450 has a potential for altering the course of the liver disease. In this phase 2, double-blind study, 124 subjects with biopsy-proven NASH were randomized to once-daily placebo or 1, 5, 10, or 40 mg GS-9450 for 4 weeks. Absolute and percent changes from baseline in ALT levels, AST levels, and caspase-3-cleaved cytokeratin (CK)-18 fragments at week 4 were assessed by an analysis of covariance model with adjustment for baseline values. In the 40-mg group, mean (SD) ALT decreased by 47 (43) U/L from baseline to week 4 (P < 0.0001 versus placebo), and the proportion of subjects with normal ALT increased from 0% to 35% at week 4. In the 40-mg group, mean AST decreased by 13 U/L from baseline (not significant), and the proportion with normal AST increased from 20% at baseline to 48% at week 4. By week 4, mean CK-18 fragment levels had decreased to 393 (723) U/L in the GS-9450 10-mg group and 125 (212) U/L in the 40-mg group, but these reductions were not statistically significant. No serious adverse events were reported during treatment, and the percentage of subjects with at least one treatment-emergent grade 3 or 4 laboratory abnormality ranged from 11.5% to 17% across the GS-9450 treatment groups versus 35% in the placebo group. CONCLUSION: GS-9450 treatment induced significant reductions in ALT levels in NASH patients. Reductions in CK-18 fragment levels also occurred, although they were not statistically significant. At appropriate therapeutic indices, selective caspase inhibitors may be a promising treatment option in patients with NASH.


Subject(s)
Caspase Inhibitors , Fatty Liver/drug therapy , Adult , Alanine Transaminase/blood , Aspartate Aminotransferases/blood , Biomarkers/blood , Double-Blind Method , Fatty Liver/blood , Female , Humans , Keratin-18/blood , Male , Middle Aged , Pilot Projects
9.
PLoS One ; 6(10): e25497, 2011.
Article in English | MEDLINE | ID: mdl-21998664

ABSTRACT

BACKGROUND: Although C/EBPß(ko) mice are refractory to Bleomycin-induced lung fibrosis the molecular mechanisms remain unknown. Here we show that blocking the ribosomal S-6 kinase (RSK) phosphorylation of the CCAAT/Enhancer Binding Protein (C/EBP)-ß on Thr217 (a RSK phosphoacceptor) with either a single point mutation (Ala217), dominant negative transgene or a blocking peptide containing the mutated phosphoacceptor ameliorates the progression of lung injury and fibrosis induced by Bleomycin in mice. METHODOLOGY/PRINCIPAL FINDINGS: Mice expressing the non-phosphorylatable C/EBPß-Ala217 transgene had a marked reduction in lung injury on day-13 after Bleomycin exposure, compared to C/EBPß(wt) mice, judging by the decrease of CD68(+) activated monocytes/macrophages, bone marrow-derived CD45(+) cells and lung cytokines as well as by the normal surfactant protein-C expression by lung pneumocytes. On day-21 after Bleomycin treatment, C/EBPß(wt) mice but not mice expressing the dominant negative C/EBPß-Ala217 transgene developed severe lung fibrosis as determined by quantitative collagen assays. All mice were of identical genetic background and back-crossed to the parental wild-type inbreed FVB mice for at least ten generations. Treatment of C/EBPß(wt) mice with a cell permeant, C/EBPß peptide that inhibits phosphorylation of C/EBPß on Thr217 (40 µg instilled intracheally on day-2 and day-6 after the single Bleomycin dose) also blocked the progression of lung injury and fibrosis induced by Bleomycin. Phosphorylation of human C/EBPß on Thr266 (human homologue phosphoacceptor) was induced in collagen-activated human lung fibroblasts in culture as well as in activated lung fibroblasts in situ in lungs of patients with severe lung fibrosis but not in control lungs, suggesting that this signaling pathway may be also relevant in human lung injury and fibrosis. CONCLUSIONS/SIGNIFICANCE: These data suggest that the RSK-C/EBPß phosphorylation pathway may contribute to the development of lung injury and fibrosis.


Subject(s)
CCAAT-Enhancer-Binding Protein-beta/chemistry , CCAAT-Enhancer-Binding Protein-beta/metabolism , Lung Injury/pathology , Pulmonary Fibrosis/pathology , Signal Transduction , Threonine , Animals , Bleomycin/adverse effects , CCAAT-Enhancer-Binding Protein-beta/genetics , Caspase 8/metabolism , Cell Death/drug effects , Disease Progression , Female , Gene Expression Regulation, Enzymologic/drug effects , Humans , Lung/pathology , Lung Injury/chemically induced , Lung Injury/metabolism , Lung Injury/prevention & control , Male , Mice , Mice, Transgenic , Myofibroblasts/drug effects , Myofibroblasts/metabolism , Myofibroblasts/pathology , Peptide Fragments/pharmacology , Phosphorylation/drug effects , Pulmonary Fibrosis/chemically induced , Pulmonary Fibrosis/metabolism , Pulmonary Fibrosis/prevention & control , Ribosomal Protein S6 Kinases/metabolism , Signal Transduction/drug effects
10.
J Clin Gastroenterol ; 41 Suppl 3: S295-9, 2007.
Article in English | MEDLINE | ID: mdl-17975479

ABSTRACT

GOALS: To analyze the role of C/EBPbeta phosphorylation on hepatic stellate cell survival/cell death. BACKGROUND: Activation and survival of stellate cells is critical for the development of liver fibrosis. C/EBPbeta phosphorylation regulates stellate cell survival by affecting caspase 8 activation. The mechanisms responsible for these effects are unknown. STUDY: We study the effects of caspase 8 activators signaling through death receptors. In addition, we assess the role of C/EBPbeta phosphorylation on the susceptibility of stellate cells to apoptotic stimuli. Finally, we investigated whether C/EBPbeta is associated with the caspase 8 complex protein FLIP, a critical inhibitor of caspase 8. RESULTS: Primary mouse stellate cells from C/EBPbeta wild type and the phosphorylation mimic C/EBPbetaGlu transgenic mice were treated with lipopolysaccharide [an inducer of tumor necrosis factor-alpha (TNF-alpha)], FAS, or TNF-alpha. Stellate cell apoptosis was determined by assessing the binding of annexin-V to exposed phosphatidylserine of plasma membranes. TNF-alpha and FAS, but not lipopolysaccharide, induced annexin-V binding at 6 hours in C/EBPbeta wild type stellate cell. However, the stimulation of apoptosis by TNF-alpha and FAS was markedly blocked in C/EBPbetaGlu stellate cells (P<0.001). Stellate cells activated on a collagen type 1 matrix expressed both C/EBPbeta and FLIPL. Treatment of stellate cells with a MAP kinase kinase1 (MEK1) inhibitor blocked FLIPL cellular localization, suggesting that MEK1 signaling through C/EBPbeta modulates FLIP activity. The colocalization of C/EBPbeta and FLIPL was disrupted by activation of the FAS receptor, by blocking the association of C/EBPbeta with the long form of FLIP, FLIPL. CONCLUSIONS: The MAPK-RSK-C/EBPbeta signaling may modulate stellate cell survival through caspase 8-associated protein FLIPL. This step is critical for liver fibrosis and if blocked with competitor peptides may prevent fibrogenesis.


Subject(s)
Apoptosis , CASP8 and FADD-Like Apoptosis Regulating Protein/metabolism , CCAAT-Enhancer-Binding Protein-beta/metabolism , Caspase 8/metabolism , Liver/metabolism , Signal Transduction , Animals , Apoptosis/drug effects , Butadienes/pharmacology , CCAAT-Enhancer-Binding Protein-beta/genetics , Cell Survival , Cells, Cultured , Collagen Type I/metabolism , Lipopolysaccharides/pharmacology , Liver/drug effects , Liver/enzymology , Liver/pathology , MAP Kinase Kinase 1/antagonists & inhibitors , MAP Kinase Kinase 1/metabolism , Mice , Mice, Transgenic , Nitriles/pharmacology , Phosphorylation , Protein Kinase Inhibitors/pharmacology , Signal Transduction/drug effects , Time Factors , Tumor Necrosis Factor-alpha/metabolism , fas Receptor/metabolism
11.
PLoS One ; 2(12): e1372, 2007 Dec 26.
Article in English | MEDLINE | ID: mdl-18159255

ABSTRACT

BACKGROUND: In response to liver injury, hepatic stellate cell (HSC) activation causes excessive liver fibrosis. Here we show that activation of RSK and phosphorylation of C/EBPbeta on Thr217 in activated HSC is critical for the progression of liver fibrosis. METHODOLOGY/PRINCIPAL FINDINGS: Chronic treatment with the hepatotoxin CCl(4) induced severe liver fibrosis in C/EBPbeta(+/+) mice but not in mice expressing C/EBPbeta-Ala217, a non-phosphorylatable RSK-inhibitory transgene. C/EBPbeta-Ala217 was present within the death receptor complex II, with active caspase 8, and induced apoptosis of activated HSC. The C/EBPbeta-Ala217 peptides directly stimulated caspase 8 activation in a cell-free system. C/EBPbeta(+/+) mice with CCl(4)-induced severe liver fibrosis, while continuing on CCl(4), were treated with a cell permeant RSK-inhibitory peptide for 4 or 8 weeks. The peptide inhibited RSK activation, stimulating apoptosis of HSC, preventing progression and inducing regression of liver fibrosis. We found a similar activation of RSK and phosphorylation of human C/EBPbeta on Thr266 (human phosphoacceptor) in activated HSC in patients with severe liver fibrosis but not in normal livers, suggesting that this pathway may also be relevant in human liver fibrosis. CONCLUSIONS/SIGNIFICANCE: These data indicate that the RSK-C/EBPbeta phosphorylation pathway is critical for the development of liver fibrosis and suggest a potential therapeutic target.


Subject(s)
CCAAT-Enhancer-Binding Protein-beta/metabolism , Liver Cirrhosis/physiopathology , Ribosomal Protein S6 Kinases/metabolism , Signal Transduction , Animals , Base Sequence , Caspase 8/metabolism , Cell-Free System , Cells, Cultured , Collagen Type I/metabolism , DNA Primers , Liver Cirrhosis/chemically induced , Liver Cirrhosis/enzymology , Liver Cirrhosis/metabolism , Mice , Mice, Transgenic
12.
Am J Physiol Cell Physiol ; 293(6): C1788-96, 2007 Dec.
Article in English | MEDLINE | ID: mdl-17855774

ABSTRACT

Bacillus anthracis lethal toxin (LT) impairs innate and adaptive immunity. Anthrax lethal factor stimulates cleavage of MAPK kinases, which prevents the activation of antiapoptotic MAPK targets. However, these MAPK targets have not been yet identified. Here, we found that LT induces macrophage apoptosis by enhancing caspase 8 activation and by preventing the activation of ribosomal S6 kinase-2 (RSK), a MAPK target, and the phosphorylation of CCAAT/enhancer binding protein-beta (C/EBPbeta) on T(217), a RSK target. Expression of the dominant positive, phosphorylation mimic C/EBPbeta-E(217) rescued macrophages from LT-induced apoptosis by blocking the activation of procaspase 8. LT inhibited macrophage phagocytosis and oxidative burst and induced apoptosis in normal mice but not in C/EBPbeta-E(217) transgenic mice. These findings suggest that C/EBPbeta may play a critical role in anthrax pathogenesis, at least in macrophages.


Subject(s)
Antigens, Bacterial/pharmacology , Apoptosis/drug effects , Bacterial Toxins/pharmacology , CCAAT-Enhancer-Binding Protein-beta/metabolism , MAP Kinase Signaling System/drug effects , Macrophages/drug effects , Animals , CCAAT-Enhancer-Binding Protein-beta/genetics , Mice , Mitogen-Activated Protein Kinase Kinases/metabolism , Phagocytosis/drug effects , Phosphorylation , Ribosomal Protein S6 Kinases, 90-kDa/metabolism
13.
World J Gastroenterol ; 13(6): 960-3, 2007 Feb 14.
Article in English | MEDLINE | ID: mdl-17352032

ABSTRACT

Advanced gastric cancer usually presents with symptoms due to direct extension into adjacent viscera, distant metastases from lymphatic or hematogenic dissemination and peritoneal seeding. However, portal hypertension as a presentation of metastatic gastric cancer is rare and usually seen in association with other malignancies, e.g. hepatocellular and pancreatic carcinoma. We report a case of signet ring adenocarcinoma of the stomach that presented with esophageal and duodenal varices and bleeding due to portal hypertensive gastropathy. Pagetoid spread of cancer cells likely caused early metastasis and the unusual presentation. We also discussed the pathophysiology of development of portal hypertension in association with malignancies.


Subject(s)
Adenocarcinoma/complications , Hypertension, Portal/etiology , Stomach Neoplasms/complications , Adenocarcinoma/diagnosis , Aged, 80 and over , Gastrointestinal Hemorrhage/diagnosis , Gastrointestinal Hemorrhage/etiology , Humans , Hypertension, Portal/diagnosis , Male , Stomach/diagnostic imaging , Stomach/pathology , Stomach Neoplasms/diagnosis , Tomography, X-Ray Computed
14.
Nephron Clin Pract ; 103(3): c100-5, 2006.
Article in English | MEDLINE | ID: mdl-16534233

ABSTRACT

BACKGROUND/AIMS: Paricalcitol is highly protein bound, extensively metabolized and eliminated primarily by hepatobiliary excretion. This study was designed to determine if hepatic disease alters the pharmacokinetics or affects the safety of paricalcitol. METHODS: Subjects with mild (n = 5) or moderate (n = 5) hepatic impairment, and subjects with normal hepatic function (n = 10) enrolled in and completed the study. Each subject was administered a single 0.24 microg/kg intravenous dose of paricalcitol, injected within 1 min. RESULTS: For both total and unbound paricalcitol, there were no statistically significant differences in the pairwise comparisons between hepatic function groups in paricalcitol concentration at 5 min postdose (C5) or area under the plasma concentration-time curve from time zero to infinity (AUC(0-infinity), except C5 of total paricalcitol between mild and moderate impairment groups (p = 0.02). Paricalcitol binding to plasma proteins was extensive in all hepatic function groups (mean values >99.7%); unbound fraction was greater in subjects with moderate impairment than either healthy subjects or subjects with mild impairment (p < 0.01). Paricalcitol appeared to be well tolerated both by healthy subjects and subjects with mild to moderate hepatic insufficiency. CONCLUSION: No adjustment of paricalcitol dose is required for subjects with mild to moderate hepatic impairment. However, caution should be exercised in extrapolating the results from this study to subjects with severe hepatic impairment.


Subject(s)
Ergocalciferols/adverse effects , Ergocalciferols/pharmacokinetics , Hepatic Insufficiency/metabolism , Adult , Blood Proteins/metabolism , Case-Control Studies , Ergocalciferols/metabolism , Hepatic Insufficiency/physiopathology , Humans , Liver/physiopathology , Male , Middle Aged , Severity of Illness Index
15.
J Clin Gastroenterol ; 39(4 Suppl 2): S143-6, 2005 Apr.
Article in English | MEDLINE | ID: mdl-15758650

ABSTRACT

The albumin gene is expressed specifically in the liver after birth, and this expression is regulated predominantly at the transcriptional level. Regulatory proteins occupy specific DNA sequences within the promoter and enhancer of the albumin gene. The interaction between the CCAAT/enhancer binding protein (C/EBP)-beta and the albumin DNA is critical for albumin synthesis. Cachexia-induced hypoalbuminemia is mediated by tumor necrosis factor (TNF)-alpha. In turn, TNF-alpha stimulates oxidative stress, NO synthesis, and phosphorylation of C/EBP-beta within its nuclear localization signal (NLS). Consequently, C/EBP-beta is exported from the nucleus, preventing it to act as a transcriptional factor on the albumin gene. Antioxidants, NOS inhibitors. and dominant negative, nonphosphorylatable C/EBP-beta peptides block phosphorylation of C/EBP-beta within the NLS and its nuclear export as well as rescue the abnormal albumin gene expression, suggesting potential therapeutic interventions.


Subject(s)
Albumins/biosynthesis , Liver/metabolism , Albumins/genetics , Albumins/physiology , Animals , CCAAT-Enhancer-Binding Proteins/metabolism , Cachexia/metabolism , Humans , Mice , Tumor Necrosis Factor-alpha/physiology
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