Oxidized lipoprotein(a) enhanced the expression of P-selectin in cultured human umbilical vein endothelial cells

Abstract

Lipoprotein(a) [Lp(a)] has been demonstrated to be an independent risk factor for coronary heart disease. However, the precise mechanism by which it contributes to the development of atherosclerosis remains unclear. P-selectin is one of the major adhesion molecules to mediate the interaction between monocytes, platelets and endothelial cells. Increased expression of P-selectin has been frequently found in atherosclerotic lesions. The present study assessed the effects of native and oxidized LDL (n-LDL and ox-LDL) and Lp(a) (n-Lp(a) and ox-Lp(a)) on the expression of P-selectin in cultured human umbilical vein endothelial cells (HUVECs). Cell ELISA was used to measure the expression of P-selectin in HUVECs and monocyte adhesion assay was used to detect whether the P-selectin expressed in HUVECs was functional. P-selectin mRNA expression in HUVECs was determined by Northern blot. Results showed that P-selectin protein expression was not influenced by n-LDL, but was moderately increased by ox-LDL and n-Lp(a). ox-Lp(a) was the most potent stimulus for P-selectin expression, increasing it in HUVECs by 144±10% at 10 nmol/l and 202±22% at 20 nmol/l. In addition, it showed that dose dependency induced monocyte adherence to endothelial cells after incubation of HUVECs with ox-Lp(a). Northern blot analysis demonstrated that the amount of P-selectin mRNA was markedly increased after treatment with ox-Lp(a) but not with n-LDL, ox-LDL and n-Lp(a). These results demonstrate that ox-Lp(a) can induce P-selectin expression in HUVECs, which may thereby influence the pathogenesis of athersclerosis.