Yamagishi S, Fujimori H, Yonekura H, Yamamoto Y, Yamamoto H
Department of Biochemistry, Kanazawa University School of Medicine, Japan.
Diabetologia. 1998 Dec;41(12):1435-41. doi: 10.1007/s001250051089.
Several thrombogenic abnormalities are associated with diabetes. To investigate the underlying molecular mechanisms, we examined the effects of advanced glycation endproducts (AGE), non-enzymatically glycated protein derivatives, on the production of prostacyclin (PGI2), an anti-thrombogenic prostanoid, and of plasminogen activator inhibitor-1 (PAI-1), a fast-acting serine protease inhibitor of fibrinolysis, in human microvascular endothelial cells (EC). Firstly, AGE-bovine serum albumin (BSA) but not non-glycated BSA, was found to considerably decrease the production of PGI2 to about two-thirds of the control value. Secondly, quantitative reverse transcription-polymerase chain reaction showed that AGE-BSA increased the EC levels of mRNA coding for PAI-1, this being associated with a concomitant increase in the immunoreactive PAI-1 contents and the anti-fibrinolytic activity. Thirdly, the effects of AGE on PGI2 and PAI-1 syntheses in EC were found to be mediated by a receptor for AGE (RAGE) because antisense DNA against RAGE mRNA could reverse the AGE effects. Further, it was found that AGE decreased the intracellular cyclic AMP concentrations in EC and that cyclic AMP agonists such as dibutyryl cyclic AMP, forskolin and PGI2 analogue reduced the AGE-stimulated PAI-1 production, suggesting the involvement of cyclic AMP in the AGE-signalling pathway. The results thus suggest that AGE have the ability to cause platelet aggregation and fibrin stabilization, resulting in a predisposition to thrombogenesis and thereby contributing to the development and progression of diabetic vascular complications.
几种血栓形成异常与糖尿病相关。为了探究潜在的分子机制，我们检测了晚期糖基化终产物（AGE），即非酶糖基化蛋白衍生物，对人微血管内皮细胞（EC）中前列环素（PGI2，一种抗血栓形成的前列腺素）和纤溶酶原激活物抑制剂-1（PAI-1，一种快速起效的纤维蛋白溶解丝氨酸蛋白酶抑制剂）产生的影响。首先，发现AGE-牛血清白蛋白（BSA）而非未糖基化的BSA，可使PGI2的产生显著降低至对照值的约三分之二。其次，定量逆转录-聚合酶链反应表明，AGE-BSA增加了编码PAI-1的mRNA的EC水平，这与免疫反应性PAI-1含量和抗纤维蛋白溶解活性的同时增加相关。第三，发现AGE对EC中PGI2和PAI-1合成的影响是由AGE受体（RAGE）介导的，因为针对RAGE mRNA的反义DNA可逆转AGE的作用。此外，发现AGE降低了EC中的细胞内环磷酸腺苷（cAMP）浓度，并且环AMP激动剂如二丁酰环AMP、福斯可林和PGI2类似物可降低AGE刺激的PAI-1产生，提示环AMP参与了AGE信号通路。因此，结果表明AGE具有引起血小板聚集和纤维蛋白稳定的能力，导致易于形成血栓，从而促进糖尿病血管并发症的发生和发展。
