Figure 2
S1P 5 activation enhances barrier endothelial integrity. S1P receptor modulators were used to determine their effect of the transendothelial electrical resistance (TEER) as assayed through ECIS. (a) The non-selective S1P receptor modulator FTY720P (10−6 M in DMSO) enhanced the TEER of hCMEC/D3 cells to 1.32 ohm.cm2 ± 0.02, n = 3 compared to vehicle control at final time point (1.10 ohm.cm2 ± 0.03, n = 3). Statistical significance (t-test) is indicated with asterisks: *P < 0.05 and **P < 0.005. (b) The selective S1P5 agonist (10−6 M in DMSO) enhanced TEER of hCMEC/D3 cells to 1.91 ohm.cm2 ± 0.03, n = 4 at final time point compared to vehicle control (1.72 ohm.cm2 ± 0.05, n = 4) (B). The Rb values represent the mean ± SEM of four independent experiments. Statistical significance (t-test) is indicated with asterisks: *P < 0.05. (c) Both the non-selective S1P receptor modulator FTY720P (10−6 M in DMSO) and the selective S1P5 agonist (10−6 M in DMSO) reduced permeability of hCMEC/D3 cells for FITC-dextran (FD 70) by 63.2% ± 4.6 (n = 4) and 61.7% ± 5.0 (n = 4), respectively. Fluorescence intensity values represent mean ± SEM of four individual experiments with hCMEC/D3 value at 5hours set at 100% (100.0% ± 11.8, n = 4). Statistical significance (t-test) is indicated with asterisks: *P < 0.05.