Activation of PAF receptor by oxidised LDL in human monocytes stimulates chemokine releases but not urokinase-type plasminogen activator expression

Abstract Background : We investigated whether the increase of urokinase-type plasminogen activator (uPA) monocyte expression and chemokine releases induced by oxidised low density lipoproteins (LDL), which participate to vascular tissue remodeling and to atherosclerotic plaque rupture, involved proinflammatory phospholipid products having platelet-activating factor (PAF)-like activity via the PAF-receptor pathway. Methods : uPA monocyte expression was stimulated by either copper ions-oxidised or O 2 − /HO free radical-oxidised LDL. The effects of PAF and oxidised LDL on the production of monocyte chemoattractant protein-1 and interleukin-8 were also examined. Results : Synthetic PAF significantly enhanced chemokine releases ( P P P Conclusion : Our results indicated that PAF-like oxidation products are responsible for the monocyte chemokine releases, but did not contribute to the enhanced monocyte uPA expression by oxidised LDL.