Figure 2.

S1P increases synthesis of proinflammatory chemokines. BMMCs were treated without (None) or with 100 nM S1P or IgE/Ag for 1 h, and total RNA was extracted. mRNA expression of the indicated cytokines (A) or chemokines (B), and L32 and GAPDH controls were determined by RPA. (C and D) BMMCs were stimulated with S1P or IgE/Ag for 4 h, and the secretion of MIP-1β (C) and MCP-1 (D) was measured by ELISA. *, P < 0.001 by Student's t test. (E and F) Chemotaxis of mast cells toward S1P. RBL-2H3 cells were allowed to migrate toward 20 μg/ml fibronectin (FN) or the indicated concentrations of S1P (E) or dihydro-S1P (F) for 2 h. Where indicated, cells were pretreated for 12 h with 200 ng/ml pertussis toxin (PTX). The data are mean ± SD of three individual wells. *, P < 0.05 by Student's t test. ^#, P < 0.05 by ANOVA. NS, not significant. Note that PTX had no effect on chemotaxis toward fibronectin.