Einfluss von Trefoilfaktor 3 auf Gliazellen

Trefoil peptide 3 (TFF3) reduces the expression of pro-inflammatory mediators in cultivated microglia Ann-Kristin Helmers, Jessica Spreu, Ralph Lucius, Uta Rickert Institutes of Anatomy Christian-Albrechts-University of Kiel Introduction: Trefoil factor 3 (TFF3) is a member of the trefoil peptide family characterized by a highly conserved motif containing 38-39 amino acids with 6 cysteine residues. Previous studies suggest an important role of the trefoil peptide family members in regeneration and the modulation of immune response of the gut (Hoffmann, 2009). Furthermore members support catabolic functions in diseased articular cartilage, activates matrix metalloproteinases and enhances apoptosis of articular cartilage chondrocytes (Rosler et al., 2010). TFF members have also been detected in the central nervous system by immunohistochemistry, especially in the cerebellum, the temporal cortex and the hippocampus (Hoffmann, 2009). In this study, we especially examied the function of TFF3 in cells of the central nervous system. Methods: Using RT-PCR and immunohistochemistry we investigated whether primary astrocytes or microglia express TFF3 and explored a possible regulation of TFF3-mRNA synthesis in inflamed microglia cells and astrocytes via quantitative PCR. To induce inflammation we utilized an in-vitro model of brain inflammation using lipopolysaccharide (LPS). Furthermore, we showed the influence of TFF3 on inflamed microglia. Therefore we measured the activation of microglia via quantification of mRNA synthesis of inducible NO synthase (iNOS) and cyclooxygenase 2 (Cox-2) and pro-inflammatory cytokines as interleukin-1β (Il-1β) and Interleuki-6 (Il-6) and tumornecrosisfactor-α (TNF-α). In addition we explored the influence of TFF3 on the quantitative Il-6 and TNF-α protein synthesis in inflamed microglia via ELISA. Finally, we investigated the intracellular signaling mechanisms triggered by TFF3 in inflamed microglia using Western blotting and immunocytochemistry. Results: RT-PCR and immunohistochemistry revealed expression and regulation by LPS of TFF3 in astrocytes, but expression in microglia was missing. Quantification of mRNA synthesis of iNOS, Cox-2 and pro-inflammatory cytokines such as Il-1β, Il-6 and TNF-α showed an inhibitory effect of TFF3 on inflamed microglia. Additionally, ELISA data demonstrated inhibition of protein synthesis of Il-6 and TNF-α. Signal transduction analysis data suggest a participation of NF-κB-signaling and a MAP-kinase pathway. Conclusion: Our results indicate that (i) cultivated astrocytes produce TFF3, which is able to (ii) decrease pro inflammatory mediators and cytokines of activated microglia cells. A major unanswered question is wether pharmacological inhibition of neuroinflammation, e.g. via TFF3, will be able to slow neurodegenerative diseases. Key words: TFF3, microglia, astrocytes, cytokines, inflammation, neuroprotection