Figure 1: Conditional deletion of S1PR1 in endothelial cell increases vascular permeability.

A, iEC-S1PR1^−/− mice were generated by crossing S1PR1^fl/fl mice with mice expressing Cre under the control of tamoxifen-inducible 5’ enhancer stem cell leukemia (Scl-CreERT) promoter. Five weeks old iEC-S1PR1^−/− and S1PR1^fl/fl mice were exposed to 80 mg/kg tamoxifen i.p. for indicated time points, followed by one-week rest. B-C, Lung S1PR1 protein expression at 11^th day post-tamoxifen injection. B, a representative blot from three independent experiments. C, densitometry of S1PR1 expression calculated as fold increase over actin. D, qPCR of indicated genes in the lungs of iEC-S1PR1^−/− and S1PR1^fl/fl mice taking GAPDH as internal control and expressed as fold change relative to S1PR1^fl/fl. The plot shows individual scatter with mean ±SD (n=3). E-F, lung vascular injury was determined post LPS administration (10 mg/kg i.p.) by measuring wet-to-dry weight ratio (E) and Evans blue albumin extravasation in lung parenchyma (F). The plots show individual values ±SD (n=7 mice/group). Statistical significance was assessed by unpaired t test for C, D, E and F (See also Online Table II). C, p=0.0001; D, p=4.64E-06; E, p=5.32E-05 and F, p=0.0001 indicate significance relative to S1PR1^fl/fl. ns= not significant.