Kim J P, Zhang K, Chen J D, Wynn K C, Kramer R H, Woodley D T
Department of Dermatology, Stanford University School of Medicine, CA 94305.
J Cell Physiol. 1992 Jun;151(3):443-50. doi: 10.1002/jcp.1041510303.
The migration of human keratinocytes over the wound bed plays an important role in the re-epithelialization of cutaneous wounds. Fibronectin, a large glycoprotein matrix component that is abundant within cutaneous wound beds, promotes keratinocyte migration. However, the mechanisms by which keratinocytes migrate over fibronectin are unknown. In this study, we sought to identify specific sites within the fibronectin molecule that induce keratinocyte locomotion and to characterize the cell surface receptors involved. The data show that the domain within the fibronectin molecule that induces human keratinocyte migration is the 120 kD cell-binding domain close to the carboxyl terminus. The 40 kD heparin-binding domain near the carboxyl terminus and the 45 kD gelatin-binding domain near the amino terminus did not promote keratinocyte migration. In addition, keratinocyte migration on both fibronectin and the 120 kD cell-binding domain was completely inhibited by the presence of GRGDSP peptide, suggesting that keratinocyte migration on fibronectin is mediated by recognizing the RGD sequence located within the cell-binding domain of fibronectin. Furthermore, keratinocytes were able to migrate directly on immobilized RGD substratum. Cell migration on fibronectin is mediated by the alpha 5 beta 1 integrin since antibodies blocking the alpha 5 and the beta 1 subunits completely inhibited keratinocyte migration on fibronectin. In addition, we demonstrate that human keratinocytes express alpha 5 beta 1 integrin in culture by flow cytometry.
人类角质形成细胞在伤口床表面的迁移在皮肤伤口的再上皮化过程中发挥着重要作用。纤连蛋白是一种大型糖蛋白基质成分，在皮肤伤口床中含量丰富，可促进角质形成细胞迁移。然而，角质形成细胞在纤连蛋白上迁移的机制尚不清楚。在本研究中，我们试图确定纤连蛋白分子内诱导角质形成细胞运动的特定位点，并表征所涉及的细胞表面受体。数据表明，纤连蛋白分子内诱导人类角质形成细胞迁移的结构域是靠近羧基末端的120 kD细胞结合结构域。靠近羧基末端的40 kD肝素结合结构域和靠近氨基末端的45 kD明胶结合结构域均未促进角质形成细胞迁移。此外，GRGDSP肽的存在完全抑制了角质形成细胞在纤连蛋白和120 kD细胞结合结构域上的迁移，这表明角质形成细胞在纤连蛋白上的迁移是通过识别位于纤连蛋白细胞结合结构域内的RGD序列介导的。此外，角质形成细胞能够直接在固定化的RGD基质上迁移。角质形成细胞在纤连蛋白上的迁移由α5β1整合素介导，因为阻断α5和β1亚基的抗体完全抑制了角质形成细胞在纤连蛋白上的迁移。此外，我们通过流式细胞术证明人类角质形成细胞在培养中表达α5β1整合素。
