Antisense to LOX-1 inhibits oxidized LDL-mediated upregulation of monocytechemoattractant protein-1 and monocyte adhesion to human coronary artery endothelial cells

Background-We have recently demonstrated a lectin-like receptor for oxidize d (ox)-LDL (LOX-1) in human coronary artery endothelial cells (HCAECs). Thi s receptor is upregulated by ox-LDL. The present study examined the signifi cance of LOX-1 in monocyte adhesion to HCAECs and endothelial injury in res ponse to ox-LDL. Methods and Results-HCAECs were incubated in the presence of antisense olig odeoxynucleotides to the 5'-coding sequence of the human LOX-1 gene (0.5 mu m/L) Basal LOX-1 mRNA and protein were suppressed by antisense LOX-1. Ox-L DL-mediated upregulation of LOX-1 was also suppressed by antisense LOX-1. I ncubation of HCAECs with ox-LDL (40 mu g/mL) for 24 hours markedly increase d monocyte chemoattractant protein-1 (MCP-1) mRNA and protein expression as well as monocyte adhesion to HCAECs (P<0.01). After 48 hours of preincubat ion of HCAECs with antisense LOX-1, ox-LDL-mediated upregulation of MCP-1 a nd monocyte adhesion to HCAECs both were suppressed (P<0.01), whereas sense LOX-1 had no effect. Whereas antisense or sense LOX-1 alone (both 0.5 nmol /L) did not injure the cells, antisense LOX-1, but not sense LOX-1, reduced ox-LDL-mediated HCAEC injury, determined as LDH release (P<0.01). Activati on of mitogen-activated protein kinase (MAPK) may play a critical role in s ignal transduction in ox-LDL-mediated alteration in MCP-1 expression, since antisense LOX-1, but not the sense LOX-1, completely inhibited the ox-LDL- induced MAPK activation. Conclusions-These observations with the first use of a specific antisense t o human LOX-1 mRNA suggest that LOX-1 is a key factor in ox-LDL-mediated mo nocyte adhesion to HCAECs.