Figure 3
NF-κB activation in RLE cells by quartz particles compared to indirect, macrophage mediator-induced NF-κB activation. A Western blot analysis of Ser32/36 phosphorylation and IκBα degradation in whole cell extracts of RLE cells treated with 10 or 40 μg/cm2 quartz (Q)for 0.5 to 24 h. TNFα (10 ng/ml, 10 min) was used as positive control for Ser32/36 phosphorylation (c = untreated cells). β-tubulin is used as loading control. B. Ser32/36-phosphorylation and IκBα degradation in RLE cells treated for 5 to 60 min with supernatants of quartz-treated (Q-MS) or untreated (c-MS) NR8383 cells (c = untreated cells). Macrophages were treated with 40 μg/cm2 DQ12 or medium for 24 h. TNFα (10 ng/ml, 10 min) was used as positive control for Ser32/36 phosphorylation. β-tubulin served as loading control. C. IκBα phosphorylation and degradation in RLE cells treated for 5 to 20 min with supernatants harvested from macrophages that were previously treated with 40 μg/cm2 quartz for 1 to 24 h (c = untreated cells; Q-MS RLE = treatment time for RLE cells with the macrophage supernatants; Q NR = treatment time for NR8383 macrophages with quartz). β-tubulin was used as loading control. D. IκBα phosphorylation and degradation in RLE cells treated with supernatants harvested from NR8383 macrophages treated for 24 h with 10, 40 or 80 μg/cm2 quartz (c = untreated cells; Q-MS RLE = treatment time for RLE cells with the macrophage supernatants; Q NR = treatment concentration for NR8383 macrophages with quartz). As loading control, blots were reprobed with a β-tubulin-antibody.