The adhesion of monocytes to activated vascular endothelial cells is a critical event in the initiation of atherosclerosis. Adhesion is mediated by oxidized low-density lipoprotein (ox-LDL) which up-regulates inflammatory markers on endothelial cells. Here we report that (±) 7, 8-dihydroxy-3-methyl-isochromanone-4 (XJP-1), an inhibitor of ox-LDL-induced adhesion of monocytes to endothelial cells blocks cellular functions which are associated with adhesion. We show that XJP-1 down-regulates ox-LDL-induced over-expression of adhesion molecules (ICAM-1 and VCAM-1) in a dose-dependent manner in human umbilical vein endothelial cells (HUVECs), attenuates ox-LDL-induced up-regulation of low-density lipoprotein receptor (LOX)-1, decreases generation of reactive oxygen species (ROS), blocks translocation of nuclear factor-kappa B (NF-κB) activity, and prevents activation of c-Jun N-terminal kinase (JNK)/p38 pathways in endothelial cells. These findings suggest that XJP-1 may attenuate ox-LDL-induced endothelial adhesion of monocytes by blocking expression of adhesion molecules through suppressing ROS/NF-κB, JNK and p38 pathways.
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