Toll-like vermittelte Expression von Chemokinen, Pro-und Antiinflammatorischen Zytokinen in der LPS-Toleranz und Kreuztoleranz innerhalb der Darmmuskularis
| Autor: | A. Hirner, B. Lüdenbach, N. T. Schwarz, Nicola Speidel |
|---|---|
| Rok vydání: | 2004 |
| Předmět: |
medicine.medical_specialty
Chemokine biology Cell adhesion molecule Chemistry medicine.medical_treatment Monocyte Molecular biology Proinflammatory cytokine Cytokine Endocrinology medicine.anatomical_structure Downregulation and upregulation Internal medicine STAT protein medicine biology.protein STAT1 |
| Zdroj: | Deutsche Gesellschaft für Chirurgie ISBN: 9783540200277 |
| Popis: | Background and aims: Endotoxin (LPS) elicits an inflammatory response within the intestinal muscularis and causes muscle dysfunction. In endotoxin tolerant mice gastrointestinal motility is not significantly influenced by further LPS exposure. LPS preconditioning also induces crosstolerance to a standard intestinal manipulation (IM). We investigated the molecular mechanisms that would underline endotoxin tolerance and cross-tolerance. Methods: Four groups of C57BL/6J mice were studied: single LPS injection (A), chronic LPS injection (B) intestinal manipulation (C) and IM mice after chronic LPS injection (D). Muscle function was measured in vivo and in vitro by transit and organ bath techniques. Nuclear factor kappa-B (NF-κB) and signal transducer and activator of transcription (STAT1 and 3) were quantified using electrophoretic mobility shift assay (EMSA). mRNA induction of Toll-like receptors, chemokines, adhesion molecules and cytokines was quantified by real-time PCR. Leukocyte recruitment into the muscularis was detected by myeloperoxidase histochemistry, and protein expression of chemokines and adhesion molecules was detected by immunhistochemistry in jejunal muscularis whole mounts and by western-blot. Results: In group A and C activation of transcription factors, upregulation of cytokine and chemokine mRNA, leukocyte and monocyte recruitment were significantly induced. Macrophages showed a strong staining for MCP-1 and endothelial cells and monocytes for ICAM-1. TLR-4 mRNA was significantly downregulated for 24 h, but protein-expression was unaffected. In vivo and in vitro muscle contractility was significantly suppressed. Molecular adaption to continuous LPS (B) was reflected in a significant blunting of transcription factor activation and inflammatory cytokine mRNA upregulation. Functional adaption was reflected in recovered muscle contractility after 7 days of continuous daily injection of LPS. Preconditioning of the muscularis showed cross-tolerance to the functional, molecular and leukocytic sequelae of intestinal manipulation (D). In endotoxin tolerized mice the anti-inflammatory cytokine IL-10 was significantly induced and the TLR-4 mRNA and protein was significantly upregulated and failed to be downregulated upon restimulation with LPS or IM. Discussion: The muscularis develops functional and molecular tolerance to endotoxin after 7 days, which confers cross-tolerance to intestinal manipulation. In tolerant mice we found an upregulation of IL-10 which has an inhibitory effect on chemokines and inflammatory cytokines in macrophages. We found a p50-p50 homodimerisation, which inhibits the transcriptional activity of the NF-KB DNA-binding motif on proinflammatory genes. The significantly upregulated TLR-4 expression could be responsible for optimizing LPS responsiveness and adaptive immune response. |
| Databáze: | OpenAIRE |
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