Fig. 1.

Effect of S1P receptor inhibition on (S)- and (R)-FTY720 regioisomer-induced barrier disruption. HPAEC were plated on gold microelectrodes for TER measurements as described in the Methods section. Bar graphs depict pooled TER data from HPAEC pre-treated for 1 h with no inhibitor (grey), 10 µM SB649146 (an inverse agonist of the S1P1 receptor, green), JTE-013 (a selective S1P2 receptor antagonist, blue), or BML-241 (a selective S1P3 receptor antagonist, purple), then stimulated with (S)- FTY720 regioisomer (10 µM), (R)-FTY720 regioisomer (10 µM), or S1P (1 µM) as indicated. The data are expressed as change in TER, compared to normalized unstimulated or inhibitor only controls, at 6 h ((S)- and (R)-FTY720 regioisomers) or 10 min (S1P) after agonist stimulation (±SEM). Normalized resistance values over 1 indicate EC barrier enhancement. Normalized resistance values under 1 indicate EC barrier disruption. n = 3-4 independent experiments per condition; *p < 0.01 agonist alone versus unstimulated cells; p < 0.05 agonist with inhibitor pretreatment versus agonist alone.

S1P: sphingosine-1-phosphate; FTY720: 2-amino-2-(2-[4-octylphenyl]ethyl)-1,3-propanediol.