Reactive oxygen intermediate-release of fibre-exposed monocytes increases inflammatory cytokine-mRNA level, protein tyrosine kinase and NF-kappaB activity in co-cultured bronchial epithelial cells (BEAS-2B).

Some pulmonary diseases like bronchitis or asthma bronchiale are mediated by inflammatory mechanisms in bronchial epithelial cells. Alveolar macrophages are located directly in the surrounding of these cells, so that we suppose an interaction between epithelial cells and macrophages regarding to the release of inflammatory mediators. For measuring the contribution of macrophages to the release of inflammatory mediators by bronchial epithelial cells, we established an in vitro model of co-cultured blood monocytes (BM) and BEAS-2B cells in a transwell system (Costar). BM were exposed to Chrysotile B and soot particle FR 101 in a concentration of 100 microg/10(6) cells. After up to 90 min exposure time ELISA, EMSA (electromobility shift assay) and RT-PCR were used to measure protein tyrosine kinase activity, protein activity of NF-kappaB and cytokine (IL-1beta, IL-6, TNF-alpha) specific mRNA levels in BEAS-2B cells. We observed an increase in protein tyrosine kinase activity (up to 1.8 +/- 0.5-fold) and NF-kappaB protein activity in BEAS-2B cells after particle or fibre exposure of co-cultured BM. Consecutive IL-1beta-, IL-6- and TNF-alpha-mRNA were elevated (up to 1.9 +/- 0.58-fold). Protein tyrosine kinase activity, NF-kappaB activity, and the synthesis of cytokine-specific mRNA were inhibited by antioxidants. These data suggest a ROI-dependent NF-kappaB mediated transcription of inflammatory cytokines in bronchial epithelial cells.