Differential effects of dominant negative mutants of desmoglein, desmocollin, and E-cadherin on cell-cell adhesion of keratinocytes.

上皮细胞间粘附被认为在复层鳞状上皮的发育和组织完整性的维持中是重要的。本研究旨在探讨经典钙粘蛋白和桥粒钙粘蛋白在维持角质形成细胞间粘附中的作用。以腺病毒为载体，研究了E-cadherin、desmoglein 3、desmocollin 3胞外区缺失突变体（E-cadDELTA EC、Dsg 3DELTA EC、Dsc 3DELTA EC）对HaCaT细胞的作用。首先，我们试图使Ad直接表达突变体。但由于毒性或其他未知的机制，我们不能使Ad。然后我们使用Ad Cre-loxP系统。LoxP侧翼突变体载体本身不表达，但AdCre的共感染开启突变体转录。在高钙条件下，免疫荧光染色显示Dsg 3DELTAEC表达仅破坏桥粒，Dsc 3DELTAEC或E-cadDELTAEC表达破坏桥粒和粘附连接。钙离子升高后2 h，所有突变体均抑制桥粒形成。但Dsg 3DELTAEc不能抑制粘附连接的形成。这些结果表明，桥粒芯糖蛋白和desniocollin可能发挥不同的作用，细胞间粘附。

Epithelial cell-cell adhesion is considered to be important in development and maintenance of tissue integrity of stratified squamous epithelium. The purpose of this study is to investigate the roles of classic and desmosomal cadherins in the maintenance of keratinocyte cell-cell adhesion. With adenovirus vector (Ad), we studied the effect of mutants of E-cadherin, desmoglein 3 , desmocollin3 which were constructed by deleting a large part of the extracellular domain (E-cadDELTA EC,Dsg3DELTA EC, Dsc3DELTA EC) on HaCaT cell. First, we tried to make Ad that directly express the mutant. But due to the toxicity or other unknown mechanism, we could not make Ad. Then we used Ad Cre-loxP system. LoxP flanked mutant vector does not express itself, but co-infection of AdCre switches on the mutant transcription. Under high calcium condition, Dsg3DELTAEC expression disrupted only desmosome, Dsc3DELTA ECor E-cadDELTAEC expression disrupted desmosome and also adherens junction in inimunofluorescence staining. By 2h after calcium elevation, all the mutants inhibited desmosome formation. But only Dsg3DELTAEc could not inhibit adherens junction formation. These results suggest that desmoglein and desniocollin may play a different role in cell-cell adhesion.