Lafay M, Laguna R, Le Bonniec B F, Lasne D, Aiach M, Rendu F
Unité INSERM 428, Faculté de Pharmacie, Paris, France.
Thromb Haemost. 1998 Apr;79(4):848-52.
Thrombin interacts with its receptor and thrombomodulin on endothelial cells. We evaluated the respective roles of these two proteins on human umbilical vein endothelial cell (HUVEC) growth by comparing thrombin, S195A (a mutant thrombin in which the serine of the charge stabilizing system had been replaced by alanine), and the receptor activating peptide (TRAP). Thrombin and TRAP induced DNA synthesis (half maximal cell proliferation with 5 nM and 25 microM, respectively), whereas S195A thrombin was inactive, inferring that growth is mediated through the thrombin receptor. Surprisingly, cells stimulated by TRAP exhibited a maximal proliferation twice greater than that obtained with thrombin. Combination of thrombin and TRAP resulted in a mitogenic response higher than by thrombin alone, but lower than by TRAP alone. The role of thrombomodulin was evaluated by adding an anti-thrombomodulin antibody, which prevents formation of the thrombin-thrombomodulin complex. Antibody did not interfere with cell proliferation induced by TRAP, but enhanced that induced by thrombin. We conclude that formation of the thrombin-thrombomodulin complex restrains HUVEC proliferation mediated through the thrombin receptor.
凝血酶与内皮细胞上的受体及血栓调节蛋白相互作用。我们通过比较凝血酶、S195A（电荷稳定系统中的丝氨酸被丙氨酸取代的突变型凝血酶）和受体激活肽（TRAP），评估了这两种蛋白质对人脐静脉内皮细胞（HUVEC）生长的各自作用。凝血酶和TRAP诱导DNA合成（分别在5 nM和25 μM时达到细胞增殖的半数最大值），而S195A凝血酶无活性，这表明生长是通过凝血酶受体介导的。令人惊讶的是，TRAP刺激的细胞表现出的最大增殖量是凝血酶刺激所得的两倍。凝血酶和TRAP联合使用导致的促有丝分裂反应高于单独使用凝血酶，但低于单独使用TRAP。通过添加抗血栓调节蛋白抗体来评估血栓调节蛋白的作用，该抗体可阻止凝血酶 - 血栓调节蛋白复合物的形成。抗体不干扰TRAP诱导的细胞增殖，但增强了凝血酶诱导的细胞增殖。我们得出结论，凝血酶 - 血栓调节蛋白复合物的形成抑制了通过凝血酶受体介导的HUVEC增殖。
