Araki Eri, Momota Yutaka, Togo Takeshi, Tanioka Miki, Hozumi Kentaro, Nomizu Motoyoshi, Miyachi Yoshiki, Utani Atsushi
Department of Dermatology, Graduate School of Medicine, Kyoto University, Kyoto 606-8507, Japan.
Mol Biol Cell. 2009 Jul;20(13):3012-24. doi: 10.1091/mbc.e08-09-0977. Epub 2009 Apr 29.
Syndecans function as receptors for extracellular matrix (ECM) with integrins in cell spreading. However, the molecular mechanism of their specific involvement in cell migration or in wound healing has not been elucidated yet. Here, we report that a synthetic peptide, PEP75, which contains the syndecan-binding sequence of the laminin alpha 3LG4 module, induces keratinocyte migration in in vitro and in vivo. Soluble PEP75 induced the clustering of syndecan-4 and conformation-modified integrin beta1 colocalized with syndecan-4 in soluble PEP75-induced clusters. Treatment of cells in solution with PEP75 resulted in the exposure of the P4G11 antibody epitope of integrin beta1 in immunostaining as well as in flow cytometry and augmented integrin beta1-dependent cell adhesion to ECM. Pulldown assays demonstrated that PEP75 bound to syndecan-4, but not to integrin beta1. A siRNA study revealed a role for syndecan-4 in PEP75-induced up-regulation of P4G11 antibody binding and migration of HaCaT cells. We conclude that binding of soluble PEP75 to syndecan-4 induces the coupling of integrin beta1, which is associated with integrin beta1-conformational changes and activation, and leads to keratinocyte migration. To activate integrin function through syndecans could be a novel therapeutic approach for chronic wound.
Syndecans在细胞铺展过程中作为细胞外基质（ECM）与整合素的受体发挥作用。然而，它们在细胞迁移或伤口愈合中具体参与的分子机制尚未阐明。在此，我们报道一种合成肽PEP75，其包含层粘连蛋白α3LG4模块的syndecan结合序列，可在体外和体内诱导角质形成细胞迁移。可溶性PEP75诱导syndecan-4聚集，且构象修饰的整合素β1与syndecan-4共定位于可溶性PEP75诱导的簇中。用PEP75处理溶液中的细胞导致免疫染色以及流式细胞术中整合素β1的P4G11抗体表位暴露，并增强了整合素β1依赖性细胞与ECM的黏附。下拉试验表明PEP75与syndecan-4结合，但不与整合素β1结合。一项siRNA研究揭示了syndecan-4在PEP75诱导的P4G11抗体结合上调和HaCaT细胞迁移中的作用。我们得出结论，可溶性PEP75与syndecan-4的结合诱导整合素β1的偶联，这与整合素β1构象变化和激活相关，并导致角质形成细胞迁移。通过syndecans激活整合素功能可能是慢性伤口的一种新型治疗方法。
