Desmoglein 2 Function in Cell Adhesion and Pemphigus

描述(申请人提供)：表皮角质形成细胞结合在一起 通过称为桥粒的细胞间连接，桥粒对 维持细胞间的黏附、组织完整性和器官功能。 桥粒蛋白(Desmogleins，DSG)是桥粒的跨膜黏附成分。 在表皮中，Dsg2和Dsg3在增生性基底层表达。 角质形成细胞表达DSGL，而DSGL表达于分化较高的细胞。那里 令人信服的证据表明，桥粒蛋白介导了细胞间的黏附。在 人类自身免疫性水疱性天疱疮，针对DSG1的抗体 Dsg3可诱导表皮和口腔粘膜产生水泡。在鼠标中， 去除Dsg3基因会导致与观察到的类似的水泡形成 寻常型天疱疮。然而，Dsg3在浅表皮肤病中强制表达 表达DSG1的表皮可防止天疱疮引起的水泡形成 叶部抗DSG1抗体。这些数据表明DSG1和Dsg3发挥了作用 一种在上皮细胞黏附中的关键作用，一种桥粒粘连蛋白可以 补偿他人的损失。Dsg2在表皮中的作用 难以捉摸的部分原因是它的表达能力很弱。这个项目的总体目标是 目的：阐明Dsg2在皮肤细胞黏附中的作用。以下是 提出了具体目标：1)展示致病性天疱疮抗体 识别Dsg2上的独特表位，2)正常表达的中断 以及3)确定Dsg2是否能够补偿 Dsg1和Dsg3的缺失。为了达到这些特定的目的，GST-融合蛋白 Dsg2的胞外区A，将用于天疱疮的特征 免疫印迹法检测血清。此外，亲和纯化的Dsg2特异性 将对天疱疮抗体进行测试，以确定与 Dsg1和Dsg3。吸附了Dsg2的天疱疮抗体将被被动检测 新生小鼠致病性的转移检测。Dsg2在生物信息学中的作用 将使用表达Dsg2的转基因小鼠在 浅层表皮受总蛋白启动子的控制，它具有 正在分化的细胞中的活性。这样的老鼠将提供有价值的 深入了解Dsg2在AFP发生发展中的生物学作用 功能性表皮与细胞增殖、分化、 粘合和粘合-她的功能。最后，被动迁移研究将是 用天疱疮免疫球蛋白确定Dsg2是否能保护抗DSG1 -和/或抗Dsg3诱导的细胞棘层松解。为此，最终的 目标是找到一种方法来上调表皮中的Dsg2，作为一种治疗方法 接近天疱疮。

DESCRIPTION (provided by applicant): Epidermal keratinocytes are held together by intercellular junctions called desmosomes, which are critical for the maintenance of cell-cell adhesion, tissue integrity, and organ function. Desmogleins (Dsg) are the transmembrane adhesive components of the desmosomes. In the epidermis, Dsg2 and Dsg3 are expressed in the proliferative basal keratinocytes while Dsgl is expressed in the upper differentiated cells. There is compelling evidence that desmogleins mediate cell-cell adhesion. In the human autoimmune blistering disease pemphigus, antibodies directed against Dsg1 and Dsg3 induce blister formation in the epidermis and oral mucosa. In mouse, ablation of the Dsg3 gene results in blister formation similar to that observed in pemphigus vulgaris. However, forced expression of Dsg3 in superficial epidermis where Dsg1 is expressed prevents blister formation by pemphigus foliaceus anti-Dsg1 antibodies. These data demonstrate that Dsg1 and Dsg3 play a pivotal role in epithelial cell adhesion and that one desmoglein can compensate the loss of another. The role of Dsg2 in the epidermis remains elusive in part due to its weak expression. The overall goal of this project is to elucidate the function of Dsg2 in cell adhesion in the skin. The following specific aims are proposed: 1) demonstration of pathogenic pemphigus antibodies that recognize unique epitopes on Dsg2, 2) disruption of the normal expression of Dsg2 in the epidermis, and 3) determining whether Dsg2 can compensate for the loss of Dsg1 and Dsg3. To achieve these specific aims, GST-fusion proteins of the extracellular domains of Dsg2,A,ill be used to characterize pemphigus sera by immunoblotting analysis. In addition, affinity purified Dsg2-specific pemphigus antibodies will be tested to determine specificity in relation to Dsg1 and Dsg3. Dsg2-adsorbed pemphigus antibodies will be tested by passive transfer assays for pathogenicity in neonatal mice. The function of Dsg2 in the epidermis will be studied using transgenic mice expressing Dsg2 in the superficial epidermis under control of the involucrin promoter, which has activity in cells undergoing differentiation. Such mice would provide valuable insights into the biological function of Dsg2 in the development of a functional epidermis with respect to cellular proliferation, differentiation, adhesion and bar-her functions. Finally passive transfer studies will be performed with pemphigus IgG to determine if Dsg2 can protect against anti-Dsg1 -and/or anti -Dsg3 -induced cellular acantholysis. To this end, the ultimate goal is to find a means to upregulate Dsg2 in the epidermis as a therapeutic approach to pemphigus.