Canfield A E, Schor A M, Loskutoff D J, Schor S L, Grant M E
Cancer Research Campaign Department of Medical Oncology, Christie Hospital and Holt Radium Institute, Manchester, U.K.
Biochem J. 1989 Apr 15;259(2):529-35. doi: 10.1042/bj2590529.
Previous studies have shown that a glycoprotein of Mr 47,000 (designated Gp47) is a major biosynthetic product of retinal endothelial cells in vitro (Canfield, Schor, West, Schor & Grant (1987) Biochem. J. 246, 121-129). We now present data indicating that (a) an identical protein is secreted by bovine retinal pericytes, (b) this protein is plasminogen activator inhibitor-type I (PAI-1), as revealed by immunoprecipitation with specific antibodies and reverse fibrin zymography, and (c) retinal endothelial cells and pericytes synthesize different species of matrix macromolecules, that is: type IV collagen is the major collagen secreted by endothelial cells, whereas pericytes produce predominantly type I collagen; fibronectin and thrombospondin are synthesized by both cell types. Our studies also indicate that PAI-1 is produced, albeit at considerably lower levels, by large vessel vascular cells (aortic endothelial and smooth muscle cells) and human skin fibroblasts. PAI-1 produced by human skin fibroblasts appears to be a distinct molecular species compared to its bovine counterpart as assessed by its slower mobility on SDS/polyacrylamide-gel electrophoresis. The potential significance of elevated PAI-1 production by retinal endothelial cells and pericytes, as well as their distinctive patterns of matrix biosynthesis, is discussed in terms of the involvement of these cells in the maintenance and remodelling of microvessel basement membrane.
以往的研究表明，一种分子量为47,000的糖蛋白（命名为Gp47）是视网膜内皮细胞在体外的主要生物合成产物（坎菲尔德、肖尔、韦斯特、肖尔和格兰特（1987年）《生物化学杂志》246卷，121 - 129页）。我们现在提供的数据表明：（a）牛视网膜周细胞分泌一种相同的蛋白质；（b）通过用特异性抗体进行免疫沉淀和反向纤维蛋白酶谱分析表明，这种蛋白质是纤溶酶原激活物抑制剂I型（PAI - 1）；（c）视网膜内皮细胞和周细胞合成不同种类的基质大分子，即：IV型胶原是内皮细胞分泌的主要胶原，而周细胞主要产生I型胶原；两种细胞类型都合成纤连蛋白和血小板反应蛋白。我们的研究还表明，大血管血管细胞（主动脉内皮细胞和平滑肌细胞）以及人皮肤成纤维细胞也产生PAI - 1，尽管产量要低得多。通过SDS /聚丙烯酰胺凝胶电泳上较慢的迁移率评估，人皮肤成纤维细胞产生的PAI - 1与其牛对应物相比似乎是一种不同的分子种类。本文从这些细胞参与微血管基底膜的维持和重塑方面，讨论了视网膜内皮细胞和周细胞PAI - 1产量升高以及它们独特的基质生物合成模式的潜在意义。
