TOX, A Novel Regulator of Thymocyte Selection

TOX，胸腺细胞选择的新型调节剂

• 批准号: 8037783
• 负责人: JONATHAN G KAYE
• 金额: $ 40.84万
• 依托单位: CEDARS-SINAI MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-12-01 至 2015-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8037783
• 关键词: Address; Adult; Affect; Animals; Appearance; Binding; Binding Sites; Breast Cancer Treatment; CD4 Positive T Lymphocytes; CD8B1 gene; Cancer cell line; Cell Lineage; Cells; Complement; Complex; DNA-Binding Proteins; Data; Development; Disease; Disease susceptibility; Ectopic Expression; Epitopes; Event; Family; Future; Gene Expression; Gene Expression Profiling; Gene Expression Regulation; Gene Family; Gene Proteins; Gene Targeting; Genes; Genome; Genomics; HMG-Box; HMGB Proteins; Health; Helper-Inducer T-Lymphocyte; Human; Immune system; Immunoprecipitation; In Vitro; Intraepithelial T-Lymphocyte; Knowledge; Laboratories; Lymphoid Tissue; MHC Class II Genes; Maps; Mass Spectrum Analysis; Molecular; Mus; Natural Killer Cells; Nuclear; Nuclear Proteins; Nucleic Acid Regulatory Sequences; Organ; Organogenesis; Pattern; Play; Population; Predisposition; Process; Property; Protein Binding; Protein Family; Proteins; Regulation; Regulatory Element; Regulatory T-Lymphocyte; Reporter; Reporting; Research; Rodent; Role; Site; Source; Staging; System; T-Cell Development; T-Lymphocyte; Testing; Thymocyte Selection; Thymus Gland; Transgenes; Transgenic Mice; Up-Regulation; Work; arm; cell type; cofactor; in vivo; insight; killer T cell; lymph nodes; malignant breast neoplasm; member; method development; mutant; novel; novel strategies; precursor cell; programs; public health relevance; reconstitution; thymocyte; tool; tumor

DESCRIPTION (provided by applicant): It has become increasingly clear that the workings of the thymus include greater complexity than first appreciated. Not only is this organ a generator of CD4 and CD8 T cells, but it is also a site for development of highly specialized lineages of natural killer T (NKT) cells, intraepithelial T lymphocytes, regulatory T (Treg) cells, and innate-like CD8 T cells. The detailed molecular mechanisms that control the differentiation of these distinct T cell sublineages from common precursors remain to be determined. Here we focus on the role of TOX (thymocyte selection-associated HMG box protein) in this context, a nuclear DNA-binding protein first identified in our laboratory as a regulator of thymic selection events. We produced TOX-deficient mice, demonstrating that TOX is required for development of the canonical CD4 T cell lineage as well as NKT and Treg cell development. Inhibition of the specific stage of T cell development that is affected in these mutant animals has not been reported previously, allowing novel insights into the process. In addition, we have found that TOX plays roles outside the thymus, including an obligatory role in NK cell development and lymph node organogenesis. We propose here three specific aims to delineate the role and mechanism of action of TOX in development of the immune system. First, we will investigate the relationship between TOX and regulation of CD4 and ThPOK expression in the thymus, the latter a dominant CD4 lineage commitment factor. In addition, we propose a novel approach to identify TOX-dependent genes involved in establishment of the CD4 lineage gene program, and will compare the role of TOX in development of different T cell lineages. Second, we will analyze the role of TOX in development of lymph node organogenesis, focusing on the potential for TOX to regulate lymphoid tissue inducer cell development. We also have replicated the inhibition of NK cell development in the absence of TOX in a culture system. We propose detailed analysis of the role for TOX in this context, including whether TOX might function to regulate another nuclear factor that shares some functional properties with TOX. Third, we propose state-of-the-art approaches to identify direct gene targets and protein binding partners of TOX, in an in vivo context of CD4 T cell development. TOX is highly conserved between rodents and humans, as is its expression pattern. Thus, these studies should provide insight into workings of the human immune system as well. TOX defines a small protein subfamily that includes three other members, one of which has been implicated as a breast cancer susceptibility locus, while TOX itself is highly expressed in some cancer cell lines and tumors. Understanding the mechanism of action of TOX is therefore likely to impact both human health and disease. PUBLIC HEALTH RELEVANCE: Development of T lymphocytes in the thymus is a complex process, but one that is key to creating a protective cellular arm of the immune system. This research program is directed at understanding the function of a small family of nuclear proteins, highly conserved in rodents and humans, in regulating this process. This knowledge will aid in future development of methods to reconstitute the immune system where necessary due to disease, and also may have future impact in treatment for breast cancer, since a gene encoding one member of this protein family has been mapped as a disease susceptibility locus.

描述（由申请人提供）：越来越清楚的是，胸腺的运作比最初理解的更加复杂。该器官不仅是 CD4 和 CD8 T 细胞的产生者，而且还是高度专业化的自然杀伤 T (NKT) 细胞、上皮内 T 淋巴细胞、调节性 T (Treg) 细胞和先天性 T 细胞谱系的发育场所。 CD8 T 细胞。控制这些不同 T 细胞亚系与常见前体细胞分化的详细分子机制仍有待确定。在这里，我们重点关注 TOX（胸腺细胞选择相关 HMG 盒蛋白）在这种情况下的作用，这是我们实验室首次鉴定的一种核 DNA 结合蛋白，作为胸腺选择事件的调节剂。 我们培育了 TOX 缺陷小鼠，证明 TOX 是典型 CD4 T 细胞谱系的发育以及 NKT 和 Treg 细胞发育所必需的。之前尚未报道过对这些突变动物中受影响的 T 细胞发育特定阶段的抑制作用，这使得人们对这一过程有了新的认识。此外，我们发现 TOX 在胸腺外发挥作用，包括在 NK 细胞发育和淋巴结器官发生中发挥重要作用。我们在此提出三个具体目标来描述 TOX 在免疫系统发育中的作用和作用机制。首先，我们将研究 TOX 与胸腺中 CD4 和 ThPOK 表达的调节之间的关系，后者是主要的 CD4 谱系定型因子。此外，我们提出了一种新方法来鉴定参与CD4谱系基因程序建立的TOX依赖性基因，并将比较TOX在不同T细胞谱系发育中的作用。其次，我们将分析 TOX 在淋巴结器官发生发育中的作用，重点关注 TOX 调节淋巴组织诱导细胞发育的潜力。我们还在培养系统中没有 TOX 的情况下复制了 NK 细胞发育的抑制作用。我们建议详细分析 TOX 在这种情况下的作用，包括 TOX 是否可能起到调节与 TOX 共享某些功能特性的另一个核因子的作用。第三，我们提出了在 CD4 T 细胞发育的体内环境中鉴定 TOX 的直接基因靶点和蛋白质结合伴侣的最先进方法。 TOX 在啮齿动物和人类之间高度保守，其表达模式也是如此。因此，这些研究也应该提供对人类免疫系统运作的深入了解。 TOX 定义了一个小蛋白质亚家族，其中包括其他三个成员，其中一个成员被认为是乳腺癌易感基因座，而 TOX 本身在一些癌细胞系和肿瘤中高度表达。因此，了解 TOX 的作用机制可能会影响人类健康和疾病。 公共卫生相关性：胸腺中 T 淋巴细胞的发育是一个复杂的过程，但却是创建免疫系统保护性细胞臂的关键。该研究计划旨在了解在啮齿动物和人类中高度保守的一小群核蛋白在调节这一过程中的功能。这一知识将有助于未来开发因疾病而必要时重建免疫系统的方法，并且还可能对乳腺癌的治疗产生未来影响，因为编码该蛋白质家族之一成员的基因已被映射为疾病易感位点。