Oxidized low-density lipoproteins stimulate adhesion of monocytes to endothelial cells
Abstract
AIM: To study the effects of oxidized low-density lipoproteins (ox-LDL) on the
adhesiveness of monocytes to endothelial cells.
METHODS: LDL was obtained from healthy human plasma by ultracentrifugation, and
oxidized by CuSO4 10 mumol.L-1. The assay of adhesion was performed using
cultured bovine aortic endothelial cells (BAEC) and human peripheral blood
monocytes.
RESULTS: Pretreatment BAEC with ox-LDL enhanced monocyte adhesion to BAEC in
time- and dose-dependent manner. ox-LDL as little as 10 mg.L-1 and 30 min of
preincubation stimulated monocyte adhesion. Cycloheximide (Cyc, a protein
synthesis inhibitor) 1 mg.L-1 and staurosporine (Sta, a PKC inhibitor) 20
nmol.L-1 abolished the effect of ox-LDL (60 mg.L-1), but dextran sulfate 20
mg.L-1 had no effect on monocyte adhesion. Phorbol 12-myristate 13-acetate (PMA)
1 nmol.L-1 and lysophosphatidylcholine (Lys) 6 mumol.L-1 mimicked the effects of
ox-LDL and potentiated monocyte adhesion. Sta also suppressed the augmentative
effects of Lys and PMA.
CONCLUSION: ox-LDL enhances the adhesion of monocytes to BAEC through the
activation of PKC.
Keywords:
adhesiveness of monocytes to endothelial cells.
METHODS: LDL was obtained from healthy human plasma by ultracentrifugation, and
oxidized by CuSO4 10 mumol.L-1. The assay of adhesion was performed using
cultured bovine aortic endothelial cells (BAEC) and human peripheral blood
monocytes.
RESULTS: Pretreatment BAEC with ox-LDL enhanced monocyte adhesion to BAEC in
time- and dose-dependent manner. ox-LDL as little as 10 mg.L-1 and 30 min of
preincubation stimulated monocyte adhesion. Cycloheximide (Cyc, a protein
synthesis inhibitor) 1 mg.L-1 and staurosporine (Sta, a PKC inhibitor) 20
nmol.L-1 abolished the effect of ox-LDL (60 mg.L-1), but dextran sulfate 20
mg.L-1 had no effect on monocyte adhesion. Phorbol 12-myristate 13-acetate (PMA)
1 nmol.L-1 and lysophosphatidylcholine (Lys) 6 mumol.L-1 mimicked the effects of
ox-LDL and potentiated monocyte adhesion. Sta also suppressed the augmentative
effects of Lys and PMA.
CONCLUSION: ox-LDL enhances the adhesion of monocytes to BAEC through the
activation of PKC.