FIGURE 3.

SphK1 suppresses neutrophil adhesion to endothelial cells and neutrophil transmigration and ROS production. A, migration of LPS-primed neutrophil across endothelial cells. *, compared with no fMLP stimulation (basal value, p < 0.05); **, increased (p < 0.05) in SphK1^−/− neutrophils compared with WT post-LPS stimulation. Results are mean of four independent experiments; bars indicate means ± S.E. B, neutrophil adhesion to endothelial cells. *, compared with no LPS stimulation, (p < 0.05, n = 4 separate experiments); **, increased (p < 0.05) adhesion compared with adhesion of WT neutrophils to WT MLVEC post-LPS stimulation. Results are mean of four independent experiments. Bars indicate means ± S.E. C, upper panel, representative time course of ICAM-1 expression after LPS (1 μg/ml) challenge of MLVEC. Endothelial cells (EC) challenged without or with LPS were homogenized, electrophoresed, and blotted with anti-ICAM-1 antibody to determine time-dependent ICAM-1 expression; lower panel, quantification of ICAM-1 expression. D, neutrophil ROS generation after LPS stimulation (1 μg/ml) determined based on luminol-ECL. cps, counts/s of light emitted. The figure shows representative curves from one of three independent experiments that produced similar results. PMN, polymorphonuclear leukocytes.