Involvement of Adenosine A2 Receptors in the Changes of Tissue Factor-Dependent Coagulant Activity Induced by Polymorphonuclear Leukocytes in Endothelial Cells

Abstract

ABSTRACT-We have already reported that polymorphonuclear leukocytes (PMNs) could increase tissue factor-dependent coagulant activity (TF activity) in endothelial cells mediated by adhesion of PMNs to endothelial cells. In the present study, the role of adenosine receptors in the changes of TF activity and of adhesion between PMNs and endothelial cells was examined. The increases of the TF activity and adhesion were significantly reduced in a concentration-dependent manner by pretreatment of adenosine (0.1 and 1.0 mM); an adenosine A 1 / A 2 -receptor agonist, CGS-21680 (5, 10 and 50 m M); and an adenosine A 2 -receptor agonist, 5'-(N-cyclopropyl)-carboxamidoadenosine (CPCA; 1.0, 10 and 100 nM). An adenosine A 2 -receptor antagonist, 3,7-dimethyl-1-(2-propynyl) xanthine (DMPX; 1.0 and 100 nM), antagonized significantly the reduction of the TF activity and the adhesion induced by adenosine (1.0 mM), while 8-cyclopentyl-1,3-dimethylxanthine (CPDMX; 1.0 and 100 nM), an adenosine A 1 -receptor antagonist, did not affect it. On the other hand, the TF activity and the adhesion were not changed by N 6 -cyclohexyladenosine (CHA; 10 and 100 nM) and 2-chloro-N-cyclopentyladenosine (CCPA; 10 and 100 nM), adenosine A 1 -receptor agonists in the same conditions. These results suggest that the reduction in the TF activity stimulated by PMNs is closely related to the adhesive inhibition between PMNs and endothelial cells through the adenosine A 2 -receptor-mediated system. Keywords: Tissue factor, Endothelial cell, Adenosine receptor, Polymorphonuclear cell, Cell adhesion In our previous report (1), polymorphonuclears leukocytes (PMNs) have been shown to lead to the increase of tissue factor-dependent coagulant activity (TF activity) in endothelial cells, which is triggered by adhesion of PMNs to endothelial cells.Adenosine receptors classified into three types, A1, A2 and A 3 are known to be located on the membrane of PMNs (2 -4). It has been shown that the blockade of adenosine A 2 receptors induces an anti-inflammatory action mediated through the inhibition of adhesion of PMNs to endothelial cells (5) and of reactive oxygen species (ROS) release from PMNs stimulated by adenosine (6). Cronstein et al. (7) have reported that adenosine A 1 receptors also play an important role in the PMNs chemotaxis, phagocytosis, and adhesion activity. Furthermore, it has been shown that the cell adhesion between PMNs and endothelial cells is inhibited by adenosine deaminase inhibitor, suggesting the intimate participation of adenosine receptors on the modulation of adhesion between PMNs and endothelial cells (8). Hence in the present study, the role of adenosine receptors on the changes of TF activity after PMNs stimulation in bovine aorta endothelial cell (BAECs) was examined by the use of agonists and antagonists for adenosine receptors. MATERIALS AND METHODS Cell isolation and cultureVascular endothelial cells were isolated from the bovine thoracic aorta (BAECs) and cultured according to the method of Yasuda et al. (9). Briefly, the endoth...

Purinergic signalling and immune cells

“…Exposure of human endothelial cells to hypoxia/re-oxygenation caused increased neutrophil adhesion, an effect prevented by adenosine [ 65 ]. Adenosine also reduced the stimulatory effect of neutrophils on tissue factor-dependent coagulant activity of endothelial cells as a result of the inhibition of neutrophil adhesion to endothelial cells mediated by A 2 receptors [ 66 ].…”

Role of extracellular ATP in immunity and intestinal defence: effects on intestinal permeability and enterocyte-driven inflammatory response

“…A1 receptor-mediated up-regulation of endothelial P-selectin expression as well as of the expression of Mac-1 by neutrophils may be responsible for the enhanced adhesion [273]. In contrast, extracellular Ado at micromolar levels inhibits adhesion of neutrophils to vascular endothelial cells [192,264,[270][271][272][274][275][276][277][278][279][280][281][282][283][284][285][286][287][288][289][290], which is thought to be mediated by A2A and A2B receptors expressed by neutrophils [192,264,[282][283][284]291]. Endothelial A3 receptors may also contribute to the Ado-mediated inhibition of adhesion [279].…”