Pindon A, Hantai D, Jandrot-Perrus M, Festoff B W
I.N.S.E.R.M. Unité 153, Paris, France.
Glia. 1997 Mar;19(3):259-68.
Thrombin's potent effects on astrocytes are mediated by a specific receptor and inhibited by a serpin, protease nexin I (PNI). Thrombomodulin (TM), a membrane protein that forms complexes with thrombin, changing its enzymatic specificity, has not been studied in astrocytes. In primary astrocyte cultures, using Western blotting and immunocytochemistry, we found a 70 kDa TM band and TM localized to the surface with an anti-mouse TM monoclonal antibody. By reverse transcriptase coupled with polymerase chain reaction (RT-PCR), we found the correct sequence for mouse TM mRNA in astrocytes. Finally, we documented calcium-dependent activation of protein C by a thrombin:TM complex with thrombin added to the astrocytes. These results indicate the presence of functionally active TM at the astrocyte surface and add support to a role for thrombin signaling in the nervous system.
凝血酶对星形胶质细胞的强大作用是由一种特定受体介导的，并被丝氨酸蛋白酶抑制剂（蛋白酶nexin I，PNI）所抑制。血栓调节蛋白（TM）是一种与凝血酶形成复合物并改变其酶特异性的膜蛋白，尚未在星形胶质细胞中进行研究。在原代星形胶质细胞培养物中，我们通过蛋白质印迹法和免疫细胞化学方法，发现了一条70 kDa的TM条带，并且使用抗小鼠TM单克隆抗体发现TM定位于细胞表面。通过逆转录酶联聚合酶链反应（RT-PCR），我们在星形胶质细胞中发现了小鼠TM mRNA的正确序列。最后，我们记录了在向星形胶质细胞中添加凝血酶后，凝血酶：TM复合物对蛋白C的钙依赖性激活。这些结果表明星形胶质细胞表面存在功能活跃的TM，并支持凝血酶信号在神经系统中的作用。
