Department of Vascular Cell Biology and Atherosclerosis Research , Research Institute of the Cleveland Clinic Foundation , Ohio 44195 .
J Biol Chem 267 : 9376-82 ( 1992)
Abstract
Injury to the vascular endothelium and the subsequent inflammatory response are considered prerequisites for the development of atherosclerosis .
Platelet-derived growth factor ( PDGF ) production by and monocyte adhesion to aortic endothelial cells ( EC ) may participate in this inflammatory process and therefore are two potential targets for control by anti-inflammatory agents .
Our previous studies have demonstrated that monocyte adhesion and PDGF production are stimulated by thrombin in EC .
Here , we provide evidence that treatment of EC with the anti-inflammatory agent 3-deazaadenosine ( c3Ado ) effectively abolished thrombin-stimulated PDGF production and monocyte adhesion .
c3Ado had no significant effect on either basal monocyte adhesion or constitutive PDGF production .
c3Ado was also effective in negating monocyte adhesion induced by other agonists , such as interleukin-1 , phorbol 12-myristate 13-acetate ( PMA ) , and lipopolysaccharide .
Northern analysis demonstrated that c3Ado significantly reduced thrombin- and PMA-stimulated steady-state levels of PDGF-A chain , PDGF-B chain , and endothelial-leukocyte adhesion molecule-1 ( ELAM-1 ) mRNAs .
Nuclear run-on studies demonstrated that a marked transcriptional activation of these genes by thrombin and PMA was abrogated by c3Ado treatment .
The transcriptional rate of the alpha-tubulin gene was unaffected by the drug .
Antibody binding studies with an anti-ELAM-1 monoclonal antibody A9 revealed that thrombin-stimulated EC expression of ELAM-1 was abolished by c3Ado , indicating that the suppression of ELAM-1 expression on EC surface may be a mechanism by which c3Ado interferes with monocyte adhesion .
Experiments with the nucleoside transport inhibitor nitrobenzylthioinosine suggested that the transport of c3Ado into EC was required for its inhibitory activity .
In addition , L-homocysteine thiolactone was found to potentiate the inhibitory activity of c3Ado , suggesting that the accumulation of intracellular c3Ado homocysteine may be the underlying mechanism by which c3Ado inhibits thrombin-induced EC function .
Taken together , these results indicate that c3Ado may prove effective against vascular injury and inflammation through its ability to inhibit induction of both monocyte adhesion and PDGF production .