N-glycosylation as a downstream effector of Interleukin-7

N-糖基化作为 Interleukin-7 的下游效应子

• 批准号: 8263748
• 负责人: Haik Mkhikian
• 金额: $ 3.45万
• 依托单位: UNIVERSITY OF CALIFORNIA-IRVINE
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-04-22 至 2016-04-21
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8263748
• 关键词: Adoptive Transfer; Affect; Area; Asses; Autoimmune Diseases; Autoimmunity; B-Lymphocytes; Blood; Blood Cells; Cell surface; Cells; Cellularity; Data; Defect; Development; Disease; Enzymes; Event; Exhibits; Experimental Autoimmune Encephalomyelitis; Galactose Binding Lectin; Genes; Genotype; Goals; Golgi Apparatus; Growth; Growth and Development function; Hematopoiesis; Hematopoietic; Homeostasis; Human; Immunologic Deficiency Syndromes; Infection; Interleukin 7 Receptor; Interleukin-7; Knockout Mice; Lead; Leukocytes; Lymphoid; Lymphopenia; Lymphopoiesis; Maintenance; Measures; Mediating; Mediator of activation protein; Membrane Glycoproteins; Modeling; Modification; Molecular; Mus; Mutant Strains Mice; Mutation; Natural Killer Cells; Organ; Organ Size; Peripheral; Phenotype; Plant Lectins; Polysaccharides; Process; Proteins; Rag1 Mouse; Receptor Signaling; Regulation; Relative (related person); Rest; Role; Severe Combined Immunodeficiency; Severities; Signal Transduction; Single Nucleotide Polymorphism; Spleen; Surface; T-Cell Activation; T-Cell Development; T-Cell Receptor; T-Lymphocyte; Thymus Gland; cell growth; cell type; cytokine; genetic manipulation; glycosylation; insight; lymph nodes; novel therapeutics; public health relevance; receptor; research study; response

DESCRIPTION (provided by applicant): Interleukin-7 (IL-7) signaling is essential for the development and peripheral maintenance of several blood cell types. Deficiencies in IL-7 or either component of its receptor result in major hematopoietic defects, causing T-cell-negative (T-), B-cell-negative (B-), natural killer cell-negative (NK-) severe combined immunodeficiency (SCID) in mice. In humans, mutations in the IL-7 receptor alpha (IL-7Ra) gene have been found to cause T-, B+, NK+ SCID, and more recently a single nucleotide polymorphism in the IL-7Ra gene has been associated with autoimmunity. In addition, IL-7 has been shown to be a critical mediator of peripheral T- cell homeostasis, survival, and function. Nevertheless, the molecular mechanism underlying the diverse functions of IL-7 remain poorly understood. We aim to uncover a new mechanism by which IL-7 signaling may regulate both T-cell development and peripheral function, namely through regulation of N-glycosylation. Insight in these areas may lead to new therapeutic avenues for both autoimmunity and congenital, acquired and induced lymphopenias. The roles of IL-7 are intricately involved with T-cell receptor (TCR) signaling, such that many of the effects of IL-7 correlate with alterations in TCR signal strength. N-glycosylation is a co-translational modification that affects nearly all cell-surface and secreted proteins. Cell surface glycoproteins interact with galectins in proportion to the number and branching of attached N-glycans, forming a molecular lattice that globally regulates the concentration and signaling of surface receptors. In T-cells, N-glycan branching opposes TCR clustering and signaling to suppress T-cell growth and autoimmunity. Our preliminary data demonstrate that IL-7 signaling leads to dramatic changes in N-glycan branching in T-cells. IL-7Ra mutant mice display a two to three fold increase in T-cell N-glycan branching, among the largest changes observed outside of genetic manipulation of Golgi enzymes. This hyper-glycosylation is predicted to markedly inhibit TCR signal strength and thus TCR signal mediated development, survival, and proliferation. We hypothesize that IL-7 regulates T-cell development and growth by altering N-glycan branching. To examine this hypothesis we propose to "rescue" hyper-glycosylation in IL-7Ra deficient mice by additionally knocking Mgat1 and Mgat5, two key N-glycan branching enzymes. This will allow us to directly asses the role of N-glycosylation in IL-7 mediated hematopoietic development, peripheral function, and homeostasis by comparing these processes in IL-7Ra-/- mice to mice with additional defect in glycosylation enzymes. These studies will provide insights about the interaction of IL-7 and TCR signaling, leading to a greater understanding of the development and maintenance of the lymphoid compartment. Furthermore, discerning the role of N-glycosylation in IL-7 signaling may provide new therapeutic avenues for both immunodeficiencies and autoimmune disease. PUBLIC HEALTH RELEVANCE: Defects in the development and growth of white blood cells impact many blood and immunological disorders. This proposal examines the signals that control the development and growth of white blood cells, which may lead to better therapies for disorders as diverse as infection, immunodeficiency and autoimmunity.

描述（由申请人提供）：白介素7（IL-7）信号传导对于几种血细胞类型的发展和周围维护至关重要。 IL-7或其受体的任何一个成分的缺陷会导致主要的造血缺陷，从而导致T细胞阴性（T-），B细胞阴性（B-），天然杀伤细胞阴性（NK-）严重的混合综合免疫性（SCID）。在人类中，已经发现IL-7受体α（IL-7RA）基因中的突变引起T-，B+，NK+ SCID，而最近，IL-7RA基因中的单个核苷酸多态性与自身免疫性有关。此外，IL-7已被证明是周围T细胞稳态，生存和功能的关键介体。然而，IL-7的不同功能的分子机制仍然吸引了知名度。我们旨在发现一种新的机制，通过该机制，IL-7信号传导可以通过调节N-糖基化来调节T细胞发育和周围功能。在这些地区的见识可能会导致自身免疫性和先天性，获得和诱导淋巴细胞减少症的新治疗途径。 IL-7的作用与T细胞受体（TCR）信号传导相关，因此IL-7的许多影响与TCR信号强度的改变相关。 N-糖基化是一种共同修饰，几乎影响所有细胞表面和分泌的蛋白质。细胞表面糖蛋白与甘叶蛋白与附着的N-聚糖的数量和分支成比例，形成了一个分子晶格，该分子晶格在全球范围内调节表面受体的浓度和信号传导。在T细胞中，N-Glycan分支反对TCR聚类和信号传导，以抑制T细胞的生长和自身免疫性。我们的初步数据表明，IL-7信号传导导致T细胞中N-聚糖分支的巨大变化。 IL-7RA突变小鼠在T细胞N-聚糖分支中表现出两到三倍的增加，这是高尔基酶基因操纵之外观察到的最大变化之一。预测这种高糖基化将显着抑制TCR信号强度，因此TCR信号介导的发育，存活和增殖。我们假设IL-7通过改变N-聚糖分支来调节T细胞的发育和生长。为了审查这一假设，我们建议通过敲击两个关键的N-聚糖分支酶的MGAT1和MGAT5来“营救” IL-7RA缺乏小鼠中的高糖基化。这将使我们能够直接评估N-糖基化在IL-7介导的造血性发育，周围功能和稳态中的作用，通过将IL-7RA - / - 小鼠中的这些过程与糖基化酶中的其他缺陷进行比较。这些研究将提供有关IL-7和TCR信号传导相互作用的见解，从而进一步了解淋巴区室的发育和维持。此外，辨别N-糖基化在IL-7信号传导中的作用可能为免疫缺陷和自身免疫性疾病提供新的治疗途径。 公共卫生相关性：白细胞发育和生长的缺陷会影响许多血液和免疫疾病。该提案研究了控制白细胞发育和生长的信号，这可能会导致更好的疗法，例如感染，免疫缺陷和自身免疫性。