Fig. 1.

Mast cell proteases induce release of the alarmin ATP in HBECs. HBECs were treated with 0.1 μg/ml and 0.5 μg/ml of tryptase (a) and chymase (b) and ATP levels were measured in cell culture supernatants after 1 h stimulation. Similarly, levels of uric acid were measured at 3 h (c) and 24 h (d). Data are presented as mean ± SEM, n = 4–12 from 3 to 6 independent experiments. *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001 compared to respective control and ^#P < 0.05, ^##P < 0.01 compared to 0.1 μg/ml of tryptase