11 research outputs found
Differential relevance of NF-κB and JNK in the pathophysiology of hemorrhage/resususcitation-induced liver injury after chronic ethanol feeding
No full textBackground: Chronic ethanol (EtOH) abuse worsens pathophysiological derangements after hemorrhagic shock and resuscitation (H/R) that induce hepatic injury and strong inflammatory changes via JNK and NF-κB activation. Inhibiting JNK with a cell-penetrating, protease-resistant peptide D-JNKI-1 after H/R in mice with healthy livers ameliorated these effects. Here, we studied if JNK inhibition by D-JNKI-1 in chronically EtOH-fed mice after hemorrhagic shock prior to the onset of resuscitation also confers protection.
Methods: Male mice were fed a Lieber-DeCarli diet containing EtOH or an isocaloric control (ctrl) diet for 4 weeks. Animals were hemorrhaged for 90 min (32 ± 2 mm Hg) and randomly received either D-JNKI-1 (11 mg/kg, intraperitoneally, i. p.) or sterile saline as vehicle (veh) immediately before the onset of resuscitation. Sham animals underwent surgical procedures without H/R and were either D-JNKI-1 or veh treated. Two hours after resuscitation, blood samples and liver tissue were harvested.
Results: H/R induced hepatic injury with increased systemic interleukin (IL)-6 levels, and enhanced local gene expression of NF-κB-controlled genes such as intercellular adhesion molecule (ICAM)-1 and matrix metallopeptidase (MMP)9. c-Jun and NF-κB phosphorylation were increased after H/R. These effects were further increased in EtOH-fed mice after H/R. D-JNKI-1 application inhibited the proinflammatory changes and reduced significantly hepatic injury after H/R in ctrl-fed mice. Moreover, D-JNKI-1 reduces in ctrl-fed mice the H/R-induced c-Jun and NF-κB phosphorylation. However, in chronically EtOH-fed mice, JNK inhibition did not prevent the H/R-induced hepatic damage and proinflammatory changes nor c-Jun and NF-κB phosphorylation after H/R.
Conclusions: These results indicate, that JNK inhibition is protective only in not pre-harmed liver after H/R. In contrast, the pronounced H/R-induced liver damage in mice being chronically fed with ethanol cannot be prevented by JNK inhibition after H/R and seems to be under the control of NF-κB
Chronic ethanol feeding modulates inflammatory mediators, activation of nuclear factor-κB, and responsiveness to endotoxin in murine Kupffer cells and circulating leukocytes
No full textChronic ethanol abuse is known to increase susceptibility to infections after injury, in part, by modification of macrophage function. Several intracellular signalling mechanisms are involved in the initiation of inflammatory responses, including the nuclear factor-κB (NF-κB) pathway. In this study, we investigated the systemic and hepatic effect of chronic ethanol feeding on in vivo activation of NF-κB in NF-κB(EGFP) reporter gene mice. Specifically, the study focused on Kupffer cell proinflammatory cytokines IL-6 and TNF-α and activation of NF-κB after chronic ethanol feeding followed by in vitro stimulation with lipopolysaccharide (LPS). We found that chronic ethanol upregulated NF-κB activation and increased hepatic and systemic proinflammatory cytokine levels. Similarly, LPS-stimulated IL-1 β release from whole blood was significantly enhanced in ethanol-fed mice. However, LPS significantly increased IL-6 and TNF-α levels. These results demonstrate that chronic ethanol feeding can improve the responsiveness of macrophage LPS-stimulated IL-6 and TNF-α production and indicate that this effect may result from ethanol-induced alterations in intracellular signalling through NF-κB. Furthermore, LPS and TNF-α stimulated the gene expression of different inflammatory mediators, in part, in a NF-κB-dependent manner
Two h after the end of resuscitation, liver tissue was harvested and western blot for the phosphorylated or non- phosphorylated c-JUN (Fig 6A), p65 subunit of NF-κB and β-actin was performed.
No full text<p>Lanes 1–4: liver protein extracts from ctrl-fed mice treated with veh, lanes 5–8: ctrl-fed mice treated with D-JNKI-1, lanes 9–12: EtOH-fed mice treated with veh and lanes 13–16: EtOH-fed mice treated with D-JNKI-1. Sham operated animals underwent the surgical procedures but hemorrhagic shock with resuscitation (H/R) was not carried out. In Fig 6B, the ratio of phosphorylated c-JUN and p65 subunit of c-JUN and NF-κB, respectively, and total protein after densitometric measurements and normalization to β-actin is represented. (*: p <0.05 <i>vs</i>. corresponding sham group, #: p <0.05 <i>vs</i>. corresponding H/R group).</p
Liver/body weight ratio from pair-fed mice with either ethanol (EtOH, n = 12) or control chow (ctrl, n = 12) is shown (Fig 1A).
No full text<p>The ratio of plasma aspartate aminotransferase (AST) and alanine aminotransferase (ALT) is presented (Fig 1B). Fig 1C represents the shed blood volume in mL that was removed for the induction and maintenance of hemorrhagic shock in either ctrl-fed or EtOH-fed vehicle (veh)-treated or D-JNKI-1-treated mice. H/R denotes hemorrhage with subsequent resuscitation. Sham operated animals underwent the same surgical procedures but H/R was not carried out. *: p <0.05 <i>vs</i>. ctrl. Fig 1D demonstrates the mean arterial blood pressure (MAP) before and during the hemorrhagic shock as well as during and after the resuscitation (n = 7–12). *: p <0.05 ctrl-veh <i>vs</i>. EtOH-veh.</p
Plasma aspartate aminotransferase (AST, Fig 2A) alanine aminotransferase (Fig 2B) and lactate dehydrogenase (LDH, Fig 2C) levels after pair-feeding with ethanol (EtOH) or control (ctrl) chow.
No full text<p>Blood was collected at 2 h after resuscitation for measurement of enzyme levels. H/R denotes hemorrhage with subsequent resuscitation, sham operated animals underwent the same surgical procedures but H/R was not carried out. D-JNKI-1 denotes treatment with the D-JNKI-1 peptide, veh represents vehicle treatment (*: p <0.05 <i>vs</i>. corresponding sham group, #: p <0.05 <i>vs</i>. corresponding H/R group, sham groups: n = 4–8, H/R groups: n = 7–12).</p
Plasma IL-6 levels (Fig 4A) and TNF-alpha (Fig 4B) levels following hemorrhagic shock and resuscitation (H/R) in pair-fed mice with ethanol (EtOH) or control (ctrl) chow.
No full text<p>Sham operated animals underwent the same surgical procedures but H/R was not carried out. D-JNKI-1 denotes treatment with the D-JNKI-1 peptide, veh represents vehicle treatment (*: p <0.05 <i>vs</i>. corresponding sham group, #: p <0.05 <i>vs</i>. corresponding H/R group, sham groups: n = 4–8, H/R groups: n = 7–12).</p
Hepatic ICAM-1 (Fig 5A) and MMP9 (Fig 5B) gene expression at 2 h after resuscitation in pair-fed mice with ethanol (EtOH) or control (ctrl) chow.
No full text<p>Sham operated animals underwent the surgical procedures but hemorrhagic shock with resuscitation (H/R) was not carried out. D-JNKI-1 denotes treatment with the D-JNKI-1 peptide, veh represents vehicle treatment. After normalization as described in material and methods, gene expression was measured as % increase compared to 100% of the corresponding sham operated group. (*: p <0.05 <i>vs</i>. corresponding sham group, #: p <0.05 <i>vs</i>. corresponding H/R group, sham groups: n = 4–8, H/R groups: n = 7–12).</p
Histological liver necrosis after pair-feeding with ethanol (EtOH) or control (ctrl) chow 2 h after resuscitation.
No full text<p>Sham operated animals underwent the same surgical procedures but hemorrhagic shock with resuscitation (H/R) was not carried out. Representative hematoxylin and eosin stained liver lobes from vehicle (veh) or D-JNKI-1-treated mice are shown (Fig 3A: ctrl-fed veh-treated mice, Fig 3B: ctrl-fed D-JNKI-1-treated mice, Fig 3C: EtOH-fed veh-treated mice, Fig 3D: EtOH-fed D-JNKI-1-treated mice after sham operation; Fig 3E: ctrl-fed veh-treated mice, Fig 3F: ctrl-fed D-JNKI-1-treated mice, Fig 3G: EtOH-fed veh-treated mice, Fig 3H: EtOH-fed D-JNKI-1-treated mice after H/R). Bar is 200 μm.</p
A novel N-ethyl-N-nitrosourea-induced mutation in phospholipase C?2 causes inflammatory arthritis, metabolic defects, and male infertility in vitro in a murine model.
No full textIt is difficult to identify a single causative factor for inflammatory arthritis because of the multifactorial nature of the disease. This study was undertaken to dissect the molecular complexity of systemic inflammatory disease, utilizing a combined approach of mutagenesis and systematic phenotype screening in a murine model.In a large-scale N-ethyl-N-nitrosourea mutagenesis project, the Ali14 mutant mouse strain was established because of dominant inheritance of spontaneous swelling and inflammation of the hind paws. Genetic mapping and subsequent candidate gene sequencing were conducted to find the causative gene, and systematic phenotyping of Ali14/+ mice was performed in the German Mouse Clinic.A novel missense mutation in the phospholipase C?2 gene (Plcg2) was identified in Ali14/+ mice. Because of the hyperreactive external entry of calcium observed in cultured B cells and other in vitro experiments, the Ali14 mutation is thought to be a novel gain-of-function allele of Plcg2. Findings from systematic screening of Ali14/+ mice demonstrated various phenotypic changes: an abnormally high T cell:B cell ratio, up-regulation of Ig, alterations in body composition, and a reduction in cholesterol and triglyceride levels in peripheral blood. In addition, spermatozoa from Ali14/+ mice failed to fertilize eggs in vitro, despite the normal fertility of the Ali14/+ male mice in vivo.These results suggest that the Plcg2-mediated pathways play a crucial role in various metabolic and sperm functions, in addition to initiating and maintaining the immune system. These findings may indicate the importance of the Ali14/+ mouse strain as a model for systemic inflammatory diseases and inflammation-related metabolic changes in humans
