Role of Dock8 in EAE

Dock8 在 EAE 中的作用

• 批准号: 9324123
• 负责人: Mohamed Oukka
• 金额: $ 24.11万
• 依托单位: SEATTLE CHILDREN'S HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-08-15 至 2018-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9324123
• 关键词: Adverse effects; Affect; Animal Model; Autoimmune Diseases; Autoimmune Process; Autoimmunity; Binding; Biological Assay; C57BL/6 Mouse; CD4 Positive T Lymphocytes; CDC42 gene; Cardiovascular Diseases; Cells; Central Nervous System Infections; DOCK1 protein; Data; Demyelinations; Dendritic Cells; Development; Disease; Experimental Autoimmune Encephalomyelitis; FDA approved; Family; Gene Deletion; Guanine Nucleotide Exchange Factors; Helper-Inducer T-Lymphocyte; Human; Hybrids; Immune; Immunity; Immunize; Inflammation; Integrin alpha Chains; Interleukin-10; Interleukin-6; JC Virus; Knockout Mice; Lesion; Life; Lymphocyte; Lymphoid Cell; Mediating; Molecular; Monoclonal Antibodies; Monomeric GTP-Binding Proteins; Mouse Strains; Multiple Sclerosis; Mus; Myelin; Myeloid Cells; Neuraxis; Oral; Organ; Pathogenesis; Pathogenicity; Pharmaceutical Preparations; Play; Progressive Multifocal Leukoencephalopathy; Protein Family; Proteins; Recruitment Activity; Relapse; Resistance; Risk; Role; STAT3 gene; Scaffolding Protein; Signal Transduction; T cell differentiation; T-Lymphocyte; Th1 Cells; Th2 Cells; Tysabri; Yeasts; analog; base; cell motility; cytokine; extracellular; in vivo; interleukin-21; interleukin-23; lymph nodes; member; migration; multiple sclerosis patient; multiple sclerosis treatment; new therapeutic target; novel; pathogen; patient subsets; prevent; public health relevance; rho GTP-Binding Proteins; sphingosine 1-phosphate; trafficking

 DESCRIPTION (provided by applicant): Th17 cells have emerged as potent inducers of autoimmune diseases. However, discovery of the mechanisms by which Th17 cells fulfill their pathogenic functions remains elusive. We have found that Th17 cells migrate quickly and accumulate in the CNS of C57BL/6 mice immunized with MOG35-55 prior to the onset of Experimental Autoimmune Encephalomyelitis (EAE), an animal model of MS, but decline rapidly thereafter when Th1 numbers are maintained. This raises the possibility that Th17 cells might be necessary for the recruitment of other pathogenic T cells, such as Th1 cells, after the peak of disease to perpetuate EAE progression. We found that DOCK8-deficient T cells differentiate poorly into Th17 cells. More importantly, DOCK8-deficient mice were completely resistant to the development of EAE. DOCK8 is one of 11 members of the DOCK180 family of proteins, some of which have been shown to function as guanine nucleotide exchange factors (GEFs) that bind and activate small GTPases of the Rho/Rac/Cdc42 family. Although it has been suggested that DOCK8 might coordinate cytoskeletal arrangement, cellular detachment and regulate cell migration, the precise role of the DOCK proteins in the cell remains for the most part unknown. It is possible that DOCK8 might act as a scaffolding protein that is important for the activation o unknown factors necessary for the differentiation and trafficking of Th17 cells. DOCK8 is mainly expressed in lymphocyte and myeloid cell subsets such as dendritic cells (DCs). However, to date we do not know the molecular mechanisms by which DOCK8 regulates the differentiation and the function of these various cell subsets. In order to investigate the in vivo role of DOCK8, we have generated a DOCK8-conditional knockout mouse in which DOCK8 expression could be specifically deleted in CD4 T cells, and Th17 cells. Based on our observation that DOCK8-deficient mice are resistant to the development of EAE, we postulate that DOCK8 could be a novel therapeutic target for the treatment of MS. In order to study how DOCK8 expression affects the pathogenesis of EAE, we propose to carry out the following specific aims: Aim 1. Determine the in vivo role of DOCK8-expressing cells in the development of EAE: We postulate, on the basis of preliminary studies, that DOCK8 plays a critical role in development of Th17 cells and their trafficking in vivo. We will use conditional DOCK8 knockout mice to determine how DOCK8 affects the function of Th17 cells in vivo. Aim 2. Determine the role of DOCK8 in T cell signaling: Based on our preliminary data, our working hypothesis is that signaling mediated by DOCK8 overlaps with, and may directly impact, STAT3 activation and function. We will assess in human and mouse T cells how DOCK8 contributes to cytokine-induced STAT3 activation such as IL-6, IL21, IL10 and IL-23.

 描述（由申请人提供）：Th17 细胞已成为自身免疫性疾病的有效诱导剂。然而，Th17 细胞履行其致病功能的机制仍然难以发现。我们发现，在实验性自身免疫性脑脊髓炎（EAE）（一种 MS 动物模型）发病前，用 MOG35-55 免疫的 C57BL/6 小鼠的 CNS 中，Th17 细胞快速迁移并积累，但此后当 Th1 数量保持不变时，Th17 细胞迅速下降。这提出了一种可能性，即在疾病高峰期后，Th17 细胞可能是招募其他致病性 T 细胞（例如 Th1 细胞）以维持 EAE 进展所必需的。我们发现 DOCK8 缺陷的 T 细胞分化为 Th17 细胞的能力较差。更重要的是，DOCK8缺陷的小鼠完全能够抵抗EAE的发展。 DOCK8 是 DOCK180 蛋白家族的 11 个成员之一，其中一些已被证明具有鸟嘌呤核苷酸交换因子 (GEF) 的功能，可结合并激活 Rho/Rac/Cdc42 家族的小 GTP 酶。尽管有人认为 DOCK8 可能协调细胞骨架排列、细胞分离和调节细胞迁移，但 DOCK 蛋白在细胞中的确切作用在很大程度上仍然未知。 DOCK8 可能充当支架蛋白，对于激活 Th17 细胞分化和运输所需的未知因子非常重要。 DOCK8主要表达于淋巴细胞和骨髓细胞亚群，例如树突状细胞（DC）。然而，迄今为止，我们还不知道 DOCK8 调节这些不同细胞亚群的分化和功能的分子机制。为了研究DOCK8的体内作用，我们构建了DOCK8条件敲除小鼠，其中CD4 T细胞和Th17细胞中的DOCK8表达可以被特异性删除。根据我们观察到 DOCK8 缺陷小鼠对 EAE 的发展具有抵抗力，我们推测 DOCK8 可能成为治疗 MS 的新治疗靶点。为了研究DOCK8表达如何影响EAE的发病机制，我们建议实现以下具体目标： 目标1.确定表达DOCK8的细胞在EAE发展中的体内作用：我们在初步研究的基础上假设DOCK8在Th17细胞的发育及其体内运输中发挥着关键作用。我们将使用条件性 DOCK8 基因敲除小鼠来确定 DOCK8 如何影响体内 Th17 细胞的功能。目标 2. 确定 DOCK8 在 T 细胞信号传导中的作用：根据我们的初步数据，我们的工作假设是 DOCK8 介导的信号传导与 STAT3 激活和功能重叠，并可能直接影响 STAT3 激活和功能。我们将在人和小鼠 T 细胞中评估 DOCK8 如何促进细胞因子诱导的 STAT3 激活，例如 IL-6、IL21、IL10 和 IL-23。