Figure 5
RANKL and oxidative stress are inducers of TRAP. (A) TRAP mRNA expression in murine MPI alveolar macrophages was significantly higher after stimulation with 200 ng/ml RANKL (n = 10) for 24 h or 16 h of exposure to xanthine/xanthine oxidase (n = 7) to mimic oxidative stress as compared to control conditions (n = 10). Exposure to 10 ng/ml M-CSF (n = 10) for 24 hrs resulted in a trend towards downregulation of TRAP mRNA expression. 10μg/ml ATP (n = 10) and 10 ng/ml IL-4 (n = 9) had no effect on TRAP mRNA expression. (B) TRAP activity was higher in precision-cut murine lung slices incubated with 200 ng/ml RANKL (n = 6) for 24 hrs as compared to slices incubated in control conditions (n = 6). No effect on TRAP activity was seen following stimulation with 10μg/ml ATP (n = 6) or xanthine/xanthine oxidase (n = 6) for 24 hrs. Differences between the multiple groups were tested with a Kruskal-Wallis test with a Dunn’s correction for multiple testing. A p value smaller than 0.05 was considered significant.
