Nedd4-family adaptors and their regulation of T cell function.

描述（由申请人提供）：粘液表面持续暴露于无害的外来抗原，例如来自食物和肠道细菌的抗原，称为环境抗原。免疫系统应该对这些环境抗原具有耐受性，就像对自身抗原一样。虽然调节对自身和环境抗原的耐受性的一些机制可能是共享的，但其他机制可能是独特的。我们已经确定了E3泛素连接酶适配器，称为Nedd4家族相互作用蛋白1（Ndfip1），调节小鼠和人的T细胞对环境抗原的耐受性。我们最近发现，缺乏Ndfip1的小鼠在肺，皮肤和胃肠道中发生特应性炎症。此外，使用单核苷酸多态性（SNP）分析，我们已经确定了基因座内的多态性，编码Ndfip1（位于人Chr5上）在哮喘、特应性皮炎（AD）和炎症性肠病（IBD）患者中更常见2，从而支持Ndfip1调节小鼠和人的特应性疾病。我们已经确定缺乏Ndfip1的T细胞响应环境抗原而被激活并产生Th2细胞因子。我们假设Ndfip1通过促进幼稚T细胞分化为iT3和诱导抗原无反应性来调节T细胞耐受性。在该提议中，我们将1）通过确定Ndfip1是否是体外和体内iTreg转化所需的，并解决Ndfip1-/-T细胞的iTreg转化缺陷是细胞内在的还是由于它们产生IL-4，来确定Ndfip1促进iTreg分化的机制。我们还将确定Ndfip1是否是TIEG1的Itch泛素化所必需的。我们还将2）测试Ndfip1-/-T细胞是否需要CD28-共刺激才能在体内被激活，使用体内和体外改变的肽配体来确定Ndfip1-/-T细胞是否被比WT细胞亲和力更低的抗原激活，并确定Ndfip1是否通过抑制TCR或IL-2R信号传导来促进野生型幼稚T细胞的抗原无反应性。最后，我们将建立这些缺陷背后的机制。我们认为，Ndfip1依赖性途径可以在治疗上靶向治疗特应性炎症性疾病，如哮喘以及T细胞介导的自身免疫性疾病。该实验室的一个长期目标是设计Ndfip1的药理学模拟物，以促进其治疗功能。我们提出的研究将有助于我们实现这一目标。

DESCRIPTION (provided by applicant): Mucosal surfaces are continuously exposed to harmless foreign antigens such as those from food and commensal bacteria, referred to as environmental antigens. The immune system should be tolerant to these environmental antigens, much as it is to self-antigens. While some mechanisms that regulate tolerance to self and environmental antigens may be shared, others may be unique. We have identified an E3 ubiquitin ligase adaptor, known as Nedd4-family interacting protein 1 (Ndfip1), that regulates T cell tolerance to environmental antigens in mice and man. We recently showed that mice lacking Ndfip1 develop atopic inflammation in lung, skin and GI tract. Additionally, using single nucleotide polymorphism (SNP) analysis, we have identified polymorphisms within the locus that encodes Ndfip1 (located on human Chr5) that are more common in patients with asthma, atopic dermatitis (AD) and inflammatory bowel disease (IBD)2, thus supporting that Ndfip1 regulates atopic disease in both mice and man. Studying Ndfip1-/- mice, we have determined that T cells lacking Ndfip1 become activated and produce Th2 cytokines in response to environmental antigens. We hypothesize that Ndfip1 regulates T cell tolerance by promoting the differentiation of na¿ve T cells into iTregs and by inducing antigen-unresponsiveness. In this proposal, we will 1) determine the mechanism by which Ndfip1 promotes iTreg differentiation by determining whether Ndfip1 is required for iTreg conversion in vitro and in vivo and resolving whether the defect in iTreg conversion of Ndfip1-/- T cells is cell intrinsic or due to their production of IL-4. We will also establish whether Ndfip1 is required for Itch ubiquitylation of TIEG1. We will also 2) test whether Ndfip1-/- T cells require CD28-costimulation to become activated in vivo, use altered peptide ligands in vivo and in vitro to establish whether Ndfip1-/- T cells are activated by lower affinity antigens than WT cells, and determine whether Ndfip1 promotes antigen unresponsiveness in wild type na¿ve T cells by dampening TCR or IL-2R signaling. Finally, we will establish the mechanism(s) underlying these defects. We believe that Ndfip1-dependent pathways could be targeted therapeutically to treat atopic inflammatory diseases such as asthma as well as T cell mediated autoimmune disease. A long-term goal of the laboratory is to design pharmacological mimics of Ndfip1 that would promote its functions therapeutically. The studies we propose will help us toward this goal.