S1PR1 knockdown protects endothelial cells from oxidized low-density lipoprotein-induced injury via reducing interleukin-1β and tumor necrosis factor-α expression

Figure 1 Sphingosine-1-phosphate receptor 1 expression in different groups. A: Sphingosine-1-phosphate receptor 1 expression in control group (71 cases) and coronary atherosclerotic heart disease group (40 cases); B: Sphingosine-1-phosphate receptor 1 expression in low Gensini score group (48 cases) and high Gensini score group (23 cases). ^aP < 0.001 vs control, ^bP < 0.01 vs low score. S1PR1: Sphingosine-1-phosphate receptor 1; CAHD: Coronary atherosclerotic heart disease.

Figure 2 Correlation between sphingosine-1-phosphate receptor 1 and cytokines in coronary atherosclerotic heart disease. A-L: The correlation between sphingosine-1-phosphate receptor 1 and 12 cytokines [interleukin (IL)-1β, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, IL-12, IL-17, tumor necrosis factor-α, interferon-α and interferon-γ] in coronary atherosclerotic heart disease. S1PR1: Sphingosine-1-phosphate receptor 1; IL: Interleukin; TNF-α: Tumor necrosis factor-α; IFN: Interferon.

Figure 3 Receiver operating characteristic curve for prediction of coronary atherosclerotic heart disease based on a combination of sphingosine-1-phosphate receptor 1, interleukin-1β and tumor necrosis factor-α levels, the area under the curve was 0. 892 (95% confidence interval: 0.834-0.949). S1PR1: Sphingosine-1-phosphate receptor 1; IL: Interleukin; TNF-α: Tumor necrosis factor-α; AUC: Area under the receiver operating characteristics curve.

Figure 4 Oxidized low-density lipoprotein-induced human umbilical vein endothelial cells injury and sphingosine-1-phosphate receptor 1 expression. A: The viability of human umbilical vein endothelial cells (HUVECs) decreased with the concentration of added oxidized low-density lipoprotein (ox-LDL); B: The apoptosis rate of HUVECs increased with the concentration of added ox-LDL; C: The viability of HUVECs decreased over time after the addition of ox-LDL; D: The apoptosis rate of HUVECs increased over time after the addition of ox-LDL; E: The quantitative real-time polymerase chain reaction results showed that sphingosine-1-phosphate receptor 1 (S1PR1) expression in HUVECs gradually increased with increasing concentrations of ox-LDL after treatment; F: The quantitative real-time polymerase chain reaction results showed that S1PR1 expression in HUVECs gradually increased over time after treatment with ox-LDL; G: The western blot results showed that S1PR1 expression in HUVECs gradually increased with increasing concentrations of ox-LDL after treatment; H: The western blot results showed that S1PR1 expression in HUVECs gradually increased over time after treatment with ox-LDL. ^aP < 0.01 vs 0 μg/mL, ^bP < 0.001 vs 0 μg/mL, ^cP < 0.05 vs 0 μg/mL, ^dP < 0.05 vs 0 hour, ^eP < 0.01 vs 0 hour, ^fP < 0.001 vs 0 hour. S1PR1: Sphingosine-1-phosphate receptor 1.

Figure 5 Cytokine levels released by human umbilical vein endothelial cells treated with oxidized low-density lipoprotein. A: The interleukin-1β levels released by human umbilical vein endothelial cells treated with 25 μg/mL of oxidized low-density lipoprotein for 24 hours; B: The tumor necrosis factor-α levels released by human umbilical vein endothelial cells treated with 25 μg/mL of oxidized low-density lipoprotein for 24 hours. ^aP < 0.01 vs 0 μg/mL. IL: Interleukin; TNF-α: Tumor necrosis factor-α.

Figure 6 Sphingosine-1-phosphate receptor 1 expression was detected after transfected with siRNA-sphingosine-1-phosphate receptor 1 and treatment with oxidized low-density lipoprotein. A and B: The expression of sphingosine-1-phosphate receptor 1 (S1PR1) was detected by quantitative real-time polymerase chain reaction and western blot after transfected with siRNA-S1PR1 and treatment with 25 μg/mL oxidized low-density lipoprotein (ox-LDL); C: The cell viability was detected by cell counting kit-8 assay after transfected with siRNA-S1PR1 and treatment with 25 μg/mL ox-LDL; D: The apoptosis ratio was detected by flow cytometry after transfected with siRNA-S1PR1 and treatment with 25 μg/mL ox-LDL; E: The interleukin-1β levels were detected by flow cytometry after transfected with siRNA-S1PR1 and treatment with 25μg/mL ox-LDL; F: The tumor necrosis factor-α levels were detected by flow cytometry after transfected with siRNA-S1PR1 and treatment with 25 μg/mL ox-LDL. ^aP < 0.01 vs siRNA-negative control, ^bP < 0.05 vs siRNA-negative control. S1PR1: Sphingosine-1-phosphate receptor 1; ox-LDL: Oxidized low-density lipoprotein; NC: Negative control.