A novel ubiquitin-ligase complex that prevents skin inflammation

描述(由申请人提供)： 项目摘要/摘要：特应性皮炎是一种使人衰弱的皮肤病，全世界有10%-20%的儿童和1%-3%的成年人受到影响。疾病的严重性是遗传和环境因素之间复杂相互作用的结果。然而，尽管发病率如此之高，人们对潜在的遗传原因却知之甚少。我们已经确定了一种可能预防特应性皮炎发展的基因。该基因编码一种名为Ndfip1的蛋白质。我们的研究表明，Ndfip1-/-小鼠表现出Th2介导的特应性皮炎样疾病并过早死亡。重要的是，编码Ndfip1的基因位于人类5号染色体上，是特应性皮炎的易感基因。我们最近发现Ndfip1调节Itch，它是E3泛素连接酶Nedd4-家族的成员。在缺乏Ndfip1的小鼠中，Itch不会泛化Jun蛋白，因此这些蛋白的水平会积累并促进Th2细胞因子的产生。虽然我们已经证明Ndfip1是Itch发挥功能所必需的，但我们认为Ndfip1也调节Nedd4家族的其他E3连接酶。基于这些数据，我们假设Ndfip1通过促进T细胞和其他细胞类型中多种Nedd4家族E3泛素连接酶的功能来预防特应性皮肤病。在这项研究中，我们将确定Ndfip1调控的细胞类型和途径。这些研究将帮助我们了解Ndfip1是如何发挥作用的，并为未来的研究奠定基础，在这些研究中，我们将以Ndfip1为靶点治疗特应性皮炎患者。为了实现这一目标，我们提出了以下目标：1)我们的初步数据表明，Ndfip1-/-T细胞在皮肤病的发生发展中是必需的，但不排除其他细胞促进疾病的进展。我们假设缺陷的Ndfip1-/-皮肤细胞促进了Ndfip1-/-小鼠的特应性皮炎样疾病。在这一目标中，我们将确定Ndfip1-/-小鼠的皮肤病是否完全是由于淋巴细胞缺陷，或者皮肤细胞的缺陷也起到了作用。目的2)我们假设缺乏Ndfip1的T细胞在影响T细胞活化的途径中存在缺陷。为了测试这一点，我们将首先确定T细胞受体特异性是否重要。然后，我们将通过限制T细胞受体信号或阻断共刺激信号来测试T细胞的激活。这些研究将揭示Ndfip1调控的途径。目的：调节性T细胞(Tregs)是一种特殊的T细胞亚群，能抑制传统的CD4+T细胞的激活。我们假设Ndfip1可能是传统T细胞对Tregs产生的抑制信号做出反应所必需的。为了测试这一点，我们将首先确定Ndfip1-/-小鼠是否含有Tregs，并测试这些Tregs是否起作用。然后我们将测试缺乏Ndfip1的T细胞是否对野生型T调节细胞的抑制做出反应。 公共卫生相关性： 项目简介：特应性皮炎是一种由遗传和环境因素引起的衰弱皮肤病。我们已经确定了一种名为Ndfip1的基因，它可能会预防特应性皮炎的发展。在这项研究中，我们将确定Ndfip1调控的细胞类型和途径。这些研究将为未来的研究奠定基础，在这些研究中，我们将以Ndfip1为靶点，治疗特应性皮炎或其他炎症性皮肤疾病患者。

DESCRIPTION (provided by applicant): Project Summary/Abstract: Atopic dermatitis is a debilitating skin disease that affects 10-20% of children and 1-3% of adults worldwide. Disease severity is the result of a complex interplay between genetic and environmental factors. Yet, in spite of such high incidence, little is known about underlying genetic causes. We have identified a gene that may prevent the development of atopic dermatitis. This gene encodes a protein known as Ndfip1. Our studies have shown that Ndfip1-/- mice exhibit a Th2-mediated atopic dermatitis-like disease and die prematurely. Importantly, the gene encoding Ndfip1 is found on human chromosome 5 within a locus of susceptibility for atopic dermatitis. We recently showed that Ndfip1 regulates Itch, a member of the Nedd4-family of E3 ubiquitin ligases. In mice lacking Ndfip1, Itch does not ubiquitinate Jun proteins and thus levels of these proteins accumulate and promote Th2 cytokine production. While we have shown that Ndfip1 is required for Itch to function, we believe that Ndfip1 also regulates other E3 ligases of the Nedd4-family. Based on these data, we hypothesize that Ndfip1 prevents atopic skin disease by promoting the function of multiple Nedd4-family E3 ubiquitin ligases in T cells as well as in other cell types. In this study we will identify cell types and pathways regulated by Ndfip1. These studies will help us understand how Ndfip1 functions and lay the foundation for future studies in which we will target Ndfip1 therapeutically to treat patients with atopic dermatitis. To accomplish this, we propose the following aims: Aim 1) Our preliminary data suggest that Ndfip1-/- T cells are necessary for the development of skin disease but do not rule out that other cells facilitate disease progression. We hypothesize that defective Ndfip1-/- skin cells promote the atopic dermatitis-like disease in Ndfip1-/- mice. In this aim we will determine whether the skin disease in Ndfip1-/- mice is due solely to defective lymphocytes, or whether defects in skin cells also contribute. Aim 2) We hypothesize that T cells lacking Ndfip1 have defects in pathways that impact T cell activation. To test this, we will first determine whether T cell receptor-specificity is important. Then, we will test T cell activation by limiting T cell receptor signaling or by blocking co-stimulatory signals. These studies will reveal pathways regulated by Ndfip1. Aim 3) Regulatory T cells (Tregs) are a specialized subset of T cells that suppress activation of conventional CD4+ T cells. We hypothesize that Ndfip1 might be required for conventional T cells to respond to inhibitory signals generated by Tregs. To test this we will first determine whether Ndfip1-/- mice contain Tregs and test whether these Tregs are functional. We will then test whether T cells lacking Ndfip1 respond to inhibition by wild type T regulatory cells. PUBLIC HEALTH RELEVANCE: Project Narrative: Atopic dermatitis is a debilitating skin disease caused by genetic and environmental factors. We have identified a gene, known as Ndfip1 that may prevent the development of atopic dermatitis. In this study we will identify cell types and pathways regulated by Ndfip1. These studies will lay the foundation for future studies in which we will target Ndfip1 therapeutically to treat patients with atopic dermatitis or other inflammatory skin conditions.