Deciphering the role of Claudin-23 in regulation of the intestinal epithelial barrier

项目摘要 肠上皮细胞（IEC）构成了一个选择性屏障，调节营养吸收和限制 抗原从内腔进入下面的粘膜。穿过肠上皮的渗透性是 由一系列生理和病理刺激动态调节。慢性肠炎患者 疾病（IBD），患有使人衰弱的胃肠道症状，这显著影响他们的生活质量， 对医疗保健系统造成不成比例的巨大经济负担。虽然遗传易感性， 环境因素和免疫失调都是IBD多因素病因学的关键因素， 越来越多的证据表明肠上皮屏障功能障碍在IBD患者中起着重要作用。 肠屏障特性通过细胞间连接的动态重塑和成熟来调节 沿着IEC的侧膜。紧密连接是细胞间最顶端的连接复合体 由高度有序的跨膜蛋白和细胞质支架蛋白组成 将复合物锚在肌动蛋白细胞骨架上。TJ跨膜蛋白的紧密连接蛋白（CLDN）家族是 由人体内的27个成员组成，通过调节TJ的密封性能来控制屏障功能。 在结肠中，CLDN差异表达以在空间上调节屏障性质。值得注意的是，CLDN 在IBD中表达受到干扰，并与屏障受损有关。然而， IEC差异表达CLDN以控制屏障功能，以及CLDN失调如何有助于 IBD中上皮屏障损害仍不清楚。在这份提案中，我们提出了令人信服的初步数据 暗示CLDN23，一个未充分研究的非经典claudin家族成员，是CLDN的中心协调者 复杂的稳定性和TJ屏障功能的IEC。此外，我们已经观察到CLDN23的表达是由细胞周期中的细胞周期决定的。 在IBD中失调。因此，我提出的研究将采用新的工具来研究CLDN23如何控制 肠上皮屏障功能，使用互补的体外和体内技术。成功完成 的拟议研究将扩大我们的知识的基本机制，控制肠上皮屏障 在健康和疾病中发挥作用，并将为研究治疗干预措施开辟新的途径， 屏障特性和改善IBD中的炎症。重要的是，这一科学建议和培训将 使我能够作为一名研究疾病机制的物理学家和科学家， 胃肠炎性疾病。

PROJECT SUMMARY Intestinal epithelial cells (IECs) constitute a selective barrier that regulates nutrient uptake and restricts antigen access from the lumen to the underlying mucosa. Permeability across the intestinal epithelium is dynamically regulated by a range of physiologic and pathologic stimuli. Patients with chronic inflammatory bowel disease (IBD), suffer from debilitating gastrointestinal symptoms that significantly impact their quality of life and pose a disproportionately large economic burden on the healthcare system. Although genetic susceptibility, environmental factors, and immune dysregulation are all critical contributors to the multifactorial etiology of IBD, there is increasing evidence suggesting a central role for intestinal epithelial barrier dysfunction in IBD patients. Intestinal barrier properties are regulated through dynamic remodeling and maturation of intercellular junctions along the lateral membrane of IECs. Tight junctions (TJs) are the most apical intercellular junctional complex and are composed of a highly organized array of transmembrane proteins and cytoplasmic scaffolding proteins that anchor the complex to the actin cytoskeleton. The claudin (CLDN) family of TJ transmembrane proteins is comprised of 27 members in humans that control barrier function by regulating the sealing properties of the TJ. In the colon, CLDNs are differentially expressed to spatially regulate barrier properties. Notably, CLDN expression is perturbed in IBD and has been linked to barrier compromise. However, the mechanisms by which IECs differentially express CLDNs to control barrier function and how CLDN dysregulation contributes to epithelial barrier compromise in IBD remain unclear. In this proposal we present compelling preliminary data implicating CLDN23, an understudied non-classical claudin family member, as a central orchestrator of CLDN complex stability and TJ barrier function in IECs. Moreover, we have observed that CLDN23 expression is dysregulated in IBD. Thus, my proposed studies will employ novel tools to investigate how CLDN23 controls intestinal epithelial barrier function using complementary in vitro and in vivo techniques. Successful completion of the proposed studies will expand our knowledge of basic mechanisms that control intestinal epithelial barrier function in health and disease, and will open new avenues for investigation of therapeutic interventions to restore barrier properties and ameliorate inflammation in IBD. Importantly, this scientific proposal and training will position me for a sustained career as a physician-scientist studying the mechanisms of disease of gastrointestinal inflammatory illnesses.