Expression of Lectin Like Oxidized Low Density Lipoprotein Receptor-1 in Endothelial Cells Induced by ox-LDL

[Objective] To investigate the expression of lectin like oxidized low density lipoprotein receptor 1 (LOX-1) of human umbilical vein endothelial cells (HUVECs) induced by oxidized low density lipoprotein (ox-LDL) after its binding and uptaking of ox-LDL. [Methods] HUVECs were incubated with native LDL (n-IDL), ox-LDL (0,10, 20, 50, and 100 μg/mL) at different time points (0, 6, 12, 24, and 36 h) or pre-incubated with 250 μg/mL of poly (Ⅰ) or carrageenan (the inhibitors of LOX-1 receptor) and then exposed in 50 μg/mL of ox-LDL. LOX-1 mRNA and protein were examined by real time reverse transcription polymerase chain reaction (Realtime RT-PCR) and Western blot analysis, respectively. [Results] Ox-LDL increased the expression of LOX-1 (mRNA and protein) in a concentration-dependent manner. In contrast, native LDL (50 μg/mL) did not affect the expression of LOX-1. Incubation of HUVECs with 50 μg/mL ox-LDL at different time points (0, 6, 12, 24, and 36 h) also increased the expression of LOX-1 (mRNA and protein) in a time-dependent manner. Pre-incubation of HUVECs with 250 μg/mL of Poly (Ⅰ) or carrageenan and addition with 50 μg/mL of ox-LDL could significantly decreased LOX-1 expression induced by ox-LDL (P＜0.01). [Conclusion] Ox-LDL increases LOX-1 expression, which is partially blocked by LOX-1 blockers. The results indicate that LOX-1 is not only the receptor of ox-LDL but also a signal molecule inducing its expression.