Shankar R, de la Motte C A, DiCorleto P E
Department of Vascular Cell Biology and Atherosclerosis Research, Research Institute of the Cleveland Clinic Foundation, Ohio 44195.
J Biol Chem. 1992 May 5;267(13):9376-82.
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 7A9 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.
血管内皮损伤及随后的炎症反应被认为是动脉粥样硬化发生的先决条件。血小板衍生生长因子（PDGF）的产生以及单核细胞与主动脉内皮细胞（EC）的黏附可能参与了这一炎症过程，因此是抗炎药物控制的两个潜在靶点。我们之前的研究表明，凝血酶可刺激EC产生单核细胞黏附和PDGF。在此，我们提供证据表明，用抗炎药物3-脱氮腺苷（c3Ado）处理EC可有效消除凝血酶刺激的PDGF产生和单核细胞黏附。c3Ado对基础单核细胞黏附或组成性PDGF产生均无显著影响。c3Ado在消除由其他激动剂（如白细胞介素-1、佛波酯12-肉豆蔻酸酯13-乙酸酯（PMA）和脂多糖）诱导的单核细胞黏附方面也有效。Northern分析表明，c3Ado显著降低了凝血酶和PMA刺激的PDGF-A链、PDGF-B链和内皮细胞-白细胞黏附分子-1（ELAM-1）mRNA的稳态水平。核转录实验表明，c3Ado处理可消除凝血酶和PMA对这些基因的显著转录激活。α-微管蛋白基因的转录速率不受该药物影响。用抗ELAM-1单克隆抗体7A9进行的抗体结合研究表明，c3Ado可消除凝血酶刺激的EC表面ELAM-1的表达，这表明抑制EC表面ELAM-1的表达可能是c3Ado干扰单核细胞黏附的一种机制。核苷转运抑制剂硝基苄硫肌苷的实验表明，c3Ado进入EC的转运是其抑制活性所必需的。此外，发现L-同型半胱氨酸硫内酯可增强c3Ado的抑制活性，这表明细胞内c3Ado同型半胱氨酸的积累可能是c3Ado抑制凝血酶诱导的EC功能的潜在机制。综上所述，这些结果表明，c3Ado可能通过其抑制单核细胞黏附和PDGF产生诱导的能力，有效对抗血管损伤和炎症。
