Inhibition of sphingosine kinase 1 (SphK1) protects adherens junction integrity via suppressing interleukin (IL)-1β release. (A) Lung tissues were harvested from mice 24 h after sham surgery or cecal ligation and puncture (CLP). Lung lysates were immunoblotted with indicated antibodies (n = 3). Data are shown as means ± SD, with one-way ANOVA, Tukey post hoc test. (B) Representative immunofluorescence staining of lung sections (n = 8) from mice 24 h after surgery. Data are shown as means ± SD, with one-way ANOVA, Tukey post hoc test. (C) Human lung microvascular endothelial monolayer treated with human recombinant IL-1β (200ng/ml) or control. The integrity of endothelial cell monolayers was quantified by transendothelial electrical resistance assay. Data are shown as means ± SD, with Student’s two-tailed t test. (D and E) Endothelial cells were challenged with IL-1β (200 ng/ml) for 24 h. Cell lysates (D) were Immunoblotted with VE-cadherin, phosphorylated vascular endothelial (VE)-cadherin at Y685, Src and phosphorylated Src at Y419. Cell membrane extraction (E) was immunoblotted with VE-cadherin antibody. Data are shown as means ± SD, with Student’s two-tailed t test. *P < 0.05; **P < 0.01; ***P < 0.001; ****P < 0.0001.