Chernousov M A, Stahl R C, Carey D J
Henry Hood M.D. Research Program, Sigfried and Janet Weis Center for Research, Penn State College of Medicine, Danville, PA 17822-2613, USA.
J Cell Sci. 1998 Sep;111 ( Pt 18):2763-77. doi: 10.1242/jcs.111.18.2763.
Cultured rat Schwann cells were stimulated to deposit fibrillar extracellular matrix by treatment with ascorbic acid in the absence of nerve cells. Immunofluoresence staining of the matrix showed that it contains collagens types I and IV, fibronectin and perlecan but not laminin. Collagen type IV, fibronectin and perlecan co-distributed completely in the matrix fibrils, whereas collagen type I was present in only a subset of these fibrils. Time course studies indicated that collagen type I fibrils appear at late stages of matrix formation. Digestion of Schwann cell extracellular matrix with collagenase effectively disrupted most of the matrix including fibronectin fibrils. This was in contrast with fibroblasts, where collagenase treatment removed collagen with no visible effect on fibronectin fibrils. alpha5 integrin was expressed on the cell surface of Schwann cells and partially codistributed with fibronectin-containing fibrils. This suggests that the inability of Schwann cells to deposit fibronectin-containing matrix through a conventional, collagen-independent mechanism was not due to the lack of fibronectin-binding integrins on their cell surface. Polyclonal anti-fibronectin antibodies inhibited the deposition of fibronectin into the matrix fibrils, whereas collagen type IV fibrils were generally unaffected. Growth of Schwann cells on collagen type IV-coated substrate in the absence of ascorbate induced deposition of fine fibronectin fibrils. These results suggest that Schwann cells use an apparently novel, collagen type IV-dependent mechanism for the deposition of fibronectin into their extracellular matrix.
在没有神经细胞的情况下，用抗坏血酸处理培养的大鼠雪旺细胞，刺激其沉积纤维状细胞外基质。对该基质进行免疫荧光染色显示，它含有I型和IV型胶原蛋白、纤连蛋白和基底膜聚糖，但不含有层粘连蛋白。IV型胶原蛋白、纤连蛋白和基底膜聚糖在基质原纤维中完全共分布，而I型胶原蛋白仅存在于这些原纤维的一个子集中。时间进程研究表明，I型胶原原纤维出现在基质形成的后期。用胶原酶消化雪旺细胞外基质有效地破坏了大部分基质，包括纤连蛋白原纤维。这与成纤维细胞形成对比，在成纤维细胞中，胶原酶处理去除了胶原蛋白，而对纤连蛋白原纤维没有明显影响。α5整合素在雪旺细胞的细胞表面表达，并与含纤连蛋白的原纤维部分共分布。这表明雪旺细胞无法通过传统的、不依赖胶原蛋白的机制沉积含纤连蛋白的基质，并非由于其细胞表面缺乏纤连蛋白结合整合素。多克隆抗纤连蛋白抗体抑制纤连蛋白沉积到基质原纤维中，而IV型胶原原纤维通常不受影响。在没有抗坏血酸的情况下，雪旺细胞在IV型胶原蛋白包被的底物上生长会诱导细纤连蛋白原纤维的沉积。这些结果表明，雪旺细胞使用一种明显新颖的、依赖IV型胶原蛋白的机制将纤连蛋白沉积到其细胞外基质中。
