Chandrasekhar S, Sorrentino J A, Millis A J
Proc Natl Acad Sci U S A. 1983 Aug;80(15):4747-51. doi: 10.1073/pnas.80.15.4747.
Fibronectins isolated fro early-passage and late-passage (in vitro aged) human fibroblasts were shown to differ in their ability to support cell adhesion and to influence cell morphology. Because fibroblast adhesion requires interactions between fibronectin, the cell surface, and the component of the extracellular matrix, we examined those functions in isolated cellular fibronectin. In comparison to fibronectin isolated from early-passage cells, fibronectin from late-passage cells bound poorly to native collagen types I and II. No differences were observed in the binding of the two fibronectins to denatured collagen. The binding of both fibronectins to native collagen was similarly promoted by heparin. Cell binding activity was evaluated by using a Boyden chamber assay to measure chemotaxis in response to either fibronectin. No differences were detected in cell binding. Comparisons of molecular weights by NaDodSO4/polyacrylamide gel electrophoresis reveals that fibronectin from late-passage cells is larger than that from early-passage cells. That difference is observed both in fibronectins isolated from conditioned media and in fibronectins isolated from the cell layer. These data support the hypothesis that late-passage cells produce a structurally and functionally distinct fibronectin. The defective binding to native collagen may account for some aspects of the aged phenotype.
从早期传代和晚期传代（体外老化）的人成纤维细胞中分离出的纤连蛋白，在支持细胞黏附及影响细胞形态的能力方面存在差异。由于成纤维细胞黏附需要纤连蛋白、细胞表面和细胞外基质成分之间的相互作用，我们对分离出的细胞纤连蛋白的这些功能进行了研究。与从早期传代细胞中分离出的纤连蛋白相比，晚期传代细胞的纤连蛋白与天然I型和II型胶原的结合较差。两种纤连蛋白与变性胶原的结合未观察到差异。肝素对两种纤连蛋白与天然胶原的结合促进作用相似。通过使用博伊登室试验来测量对任一纤连蛋白的趋化作用，评估细胞黏附活性。在细胞黏附方面未检测到差异。通过十二烷基硫酸钠/聚丙烯酰胺凝胶电泳对分子量进行比较，结果显示晚期传代细胞的纤连蛋白比早期传代细胞的纤连蛋白大。从条件培养基和细胞层中分离出的纤连蛋白均观察到这种差异。这些数据支持了晚期传代细胞产生结构和功能不同的纤连蛋白这一假说。与天然胶原结合缺陷可能解释了老化表型的某些方面。
