Role of CD98 in Intestinal Permeability

项目摘要 主要的上皮通透性屏障受一系列事件的控制和调节 由同型和异型细胞/细胞相互作用和细胞/细胞外基质(ECM)触发 互动。自从开始这项研究以来，我们已经证明了CD98，一种II型膜 糖蛋白，与肠上皮细胞中的氨基酸转运体共价连接，形成 杂二聚体。在肠上皮细胞中，异源二聚体与1-整合素和 细胞间黏附分子-1(ICAM-1)在细胞内形成大分子复合体 极化的肠上皮细胞的基侧膜。胞外C-末端 CD98的结构域包含一个与细胞外基质蛋白/蛋白有作用的PDZ结合域 互动。促炎症细胞因子介导上皮细胞CD98表达上调 干扰素在肠道炎症过程中的作用。我们的总体假设是 大分子复合体可能控制细胞/细胞、细胞/基质等重要功能 互动。这项建议的第一个目的是研究上皮细胞的功能效应。 CD98表达对体内外肠道屏障功能的影响。具体地说，我们将确定 影响肠上皮细胞通透性屏障的特定分子CD98结构域。 其次，我们将研究CD98在上皮/T细胞和上皮/基质相互作用中的作用。 此外，我们将确定与这些相关的CD98分子结构域 互动。最后，我们将研究CD98在T淋巴细胞中表达的作用 一种体内的方法。 该项目将涉及各种生化、分子、体外和体内的 接近了。体外实验将使用肠上皮细胞系Caco 2-BBE和免疫 细胞株Jurkat在分子和生化水平上的表达/功能研究 CD98在肠炎中的作用在体内的实验将使用携带有条件的 CD98基因与实验性结肠炎小鼠的关系 需要设计治疗策略来改善肠道炎症状况 包括IBD。 在美国，有100多万成年人和儿童患有炎症性肠病。 基于对IBD发病机制的更好理解，新的治疗策略将 加强对本病患者的临床护理。

Project Summary The major epithelial permeability barriers are controlled and regulated by a cascade of events triggered by homotypic and heterotypic cell/cell interactions and cell/extracellular matrix (ECM) interactions. Since starting this research, we have demonstrated that CD98, a type II membrane glycoprotein, is covalently linked to an amino-acid transporter in intestinal epithelial cells to form a heterodimer. In intestinal epithelia, the heterodimer is associated with ¿1-integrin and intercellular adhesion molecular 1 (ICAM-1) to form a macromolecular complex in the basolateral membranes of polarized intestinal epithelial cells. The extracellular C-terminal domain of CD98 contains a PDZ-binding domain that has a role in ECM protein/protein interactions. Epithelial CD98 up-regulation is mediated by the pro-inflammatory cytokine interferon ¿ (IFN-¿) during intestinal inflammation. Our overall hypothesis is that the macromolecular complex may control important functions such as cell/cell and cell/matrix interactions. The first aim of this proposal is to investigate the functional effects of epithelial CD98 expression on in-vitro and in-vivo intestinal barrier function. Specifically, we will identify the specific molecular CD98 domains that affect intestinal epithelia permeability barriers. Second, we will investigate the role of CD98 in epithelial/T cell and epithelial/matrix interactions. Furthermore, we will identify the CD98 molecular domains that are responsible for these interactions. Finally, we will examine the role of CD98 that is expressed in T lymphocytes using an in-vivo approach. The project will involve a variety of biochemical, molecular, in vitro and in vivo approaches. In vitro experiments will use intestinal epithelial cell line Caco2-BBE and immune cell line Jurkat to investigate at the molecular and biochemical levels the expression/function of CD98 in intestinal inflammation. In vivo experiments will use mice that harbored a conditional CD98 gene and experimental colitis mice in order to confirm and develop the key information needed to design therapeutic strategies to ameliorate intestinal inflammatory conditions including IBD. Over one million adults and children in the U.S, suffer from inflammatory bowel disease. New therapeutic strategies based on a better understanding of the pathogenesis of IBD will improve the clinical care of patient with this disorder.