NEDD4 IN T HELPER CELL DEVELOPMENT AND AUTOIMMUNITY

NEDD4 在辅助细胞发育和自身免疫中的作用

• 批准号: 9547050
• 负责人: JIAN ZHANG
• 金额: $ 51.41万
• 依托单位: UNIVERSITY OF IOWA
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-12-01 至 2021-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9547050
• 关键词: NEDD4; HELPER; CELL; DEVELOPMENT; AUTOIMMUNITY

Project Summary T helper (Th) 17 cells are thought to play a key role in the development and pathogenesis of autoimmune diseases, including multiple sclerosis (MS) and its murine models, experimental autoimmune encephalomyelitis (EAE), rheumatoid arthritis, inflammatory bowel disease, and systemic lupus erythematosus. The development of Th17 cells is controlled by RORγt, and small molecules that target RORγt attenuate Th17 response and the severity of EAE and cutaneous inflammation. However, the regulation of RORγt activity during Th17 cell differentiation by TCR signaling is largely unknown. Nedd4 (also known as Nedd4-1, neuronal precursor cell- expressed developmentally down-regulated 4) is a HECT-type E3 ubiquitin ligase. Through sequence analysis, we identified a PPLYKEL motif, an extended Nedd4 WW domain-binding motif, at the carboxyl terminus of the RORγt ligand-binding domain, suggesting that RORγt may be a binding partner of Nedd4. Indeed, Nedd4 is tyrosine-phosphorylated and activated upon TCR/CD28 stimulation and binds to RORγt which undergoes K63- linked poly-ubiquitination. This ubiquitination is abrogated in T cells lacking Nedd4. Further analysis showed that although Nedd4 deficiency does not impair Th1, Th2, and inducible regulatory T cell differentiation, Th17 cell differentiation is greatly compromised in the absence of Nedd4. In support of this observation, mice deficient for Nedd4, or deficient for Nedd4 in T cells, have ameliorated EAE with impaired Th17 responses. Based upon these preliminary data, we hypothesize that upon T cell antigenic stimulation Nedd4 is activated by Src kinase(s), and targets RORγt for K63-linked polyubiquitination, thus regulating Th17 responses and the susceptibility to EAE in mice and possibly MS in humans. In this proposal, we will investigate 1) How Nedd4 potentiates Th17 cell differentiation in vitro; 2) Whether Nedd4 promotes Th17 responses in vivo, regulating the susceptibility to EAE; and 3) How Nedd4 is activated in T cells in response to TCR/CD28 stimulation. The identification of Nedd4 as a key molecule regulating Th17 responses and the pathogenesis of EAE, and possibly MS, will have potential implications for using this molecule as a therapeutic target to treat autoimmune diseases involving Th17.

项目概要 辅助 T (Th) 17 细胞被认为在自身免疫性疾病的发生和发病机制中发挥着关键作用 疾病，包括多发性硬化症（MS）及其小鼠模型、实验性自身免疫性脑脊髓炎 (EAE)、类风湿性关节炎、炎症性肠病和系统性红斑狼疮的发展。 Th17 细胞的反应受 RORγt 控制，靶向 RORγt 的小分子会减弱 Th17 反应， EAE 和皮肤炎症的严重程度，然而，Th17 细胞期间 RORγt 活性的调节。 TCR 信号传导的分化很大程度上未知。 表达发育下调4)是一种HECT型E3泛素连接酶通过序列分析， 我们在 PPLYKEL 基序，一个扩展的 Nedd4 WW 域结合基序，位于 RORγt 配体结合结构域，表明 RORγt 可能是 Nedd4 的结合伴侣。 酪氨酸磷酸化并在 TCR/CD28 刺激下被激活，并与经历 K63- 的 RORγt 结合 进一步的分析表明，这种泛素化在缺乏 Nedd4 的 T 细胞中被消除。 尽管 Nedd4 缺陷不会损害 Th1、Th2 和诱导性调节性 T 细胞分化，但 Th17 细胞 缺乏 Nedd4 的小鼠的分化会受到很大影响。 基于这些，Nedd4 或 T 细胞中 Nedd4 缺陷可改善 EAE 并导致 Th17 反应受损。 初步数据显示，在 T 细胞抗原刺激下，Nedd4 被 Src 激酶激活，并且 靶向 RORγt 进行 K63 连接的多聚泛素化，从而调节 Th17 反应和 EAE 易感性 小鼠和可能的人类 MS 在本提案中，我们将研究 1) Nedd4 如何增强 Th17 细胞。 体外分化；2）Nedd4是否促进体内Th17反应，调节EAE易感性； 3) Nedd4 如何在 T 细胞中响应 TCR/CD28 刺激而被激活 Nedd4 的鉴定。 调节 Th17 反应和 EAE 以及可能的 MS 发病机制的关键分子将具有潜力 使用该分子作为治疗靶点来治疗涉及 Th17 的自身免疫性疾病的意义。