Regulation of B cell function in demyelinating disease by N-glycan branching

N-聚糖分支调节脱髓鞘疾病中的 B 细胞功能

• 批准号: 10311524
• 负责人: MICHAEL DEMETRIOU
• 金额: $ 50.05万
• 依托单位: UNIVERSITY OF CALIFORNIA-IRVINE
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-01-14 至 2023-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10311524
• 关键词: Anti-Inflammatory Agents; Antibody Formation; Antigen-Presenting Cells; Antigens; Autoimmune Diseases; Autoimmunity; B cell therapy; B-Cell Antigen Receptor; B-Lymphocytes; Binding; Binding Proteins; CD19 gene; CTLA4 gene; Cell Count; Cell Differentiation process; Cell physiology; Cell surface; Cells; Cerebrospinal Fluid; Data; Demyelinating Diseases; Demyelinations; Disease; Endocytosis; Environment; Family member; Galactose Binding Lectin; Genetic; Genetic Variation; Growth Inhibitors; Human; Human Genetics; Hyperactivity; Immune; Immune system; Individual; Inflammatory; Interleukin-10; Ligands; Mediating; Membrane Glycoproteins; Metabolic; Mixed Lymphocyte Culture Test; Monoclonal Antibody CD20; Multiple Sclerosis; Mus; Nerve Degeneration; PL/J Mouse; PLCgamma2; Pathway interactions; Phenotype; Plasma Cells; Play; Polysaccharides; Predisposition; Production; Protein Glycosylation; Proteins; Publishing; Receptor Signaling; Regulation; Role; Signal Transduction; Surface; T cell response; T-Cell Receptor; T-Lymphocyte; TLR2 gene; TLR4 gene; TNF gene; Testing; Th1 Cells; Th2 Cells; Toll-like receptors; Work; adaptive immune response; anti-CD20; axon injury; immune function; immunological synapse; link protein; multiple sclerosis patient; neuron loss; receptor; receptor function; response; sugar; virtual

Abstract Our published work has revealed that deficiencies in Asn (N)-linked protein glycosylation reduce inflammatory demyelination in mice and are associated with Multiple Sclerosis (MS). Deficiency in the branching of N-glycan's attached to proteins, either induced experimentally in mice or via natural genetic variation in humans, promotes T-cell mediated inflammatory demyelination and neurodegeneration. For example, branching deficiency induces a spontaneous and slowly progressive MS-like disease in PL/J mice, characterized by inflammatory demyelination, axonal damage and neuronal death. Mechanistically, the branching and number of N-glycans per protein molecule cooperate to regulate binding to galectins, a 14- member family of sugar binding proteins. Galectin binding to cell surface glycoproteins, via their attached N- glycans, forms a macro-molecular lattice at the cell surface that controls the distribution, clustering and endocytosis of surface glycoproteins in a coordinated and predictable manner. N-glycan branching markedly inhibits T cell activity in mice and humans by reducing T cell receptor clustering/signaling at the immune synapse, promoting surface retention of the growth inhibitor CTLA-4 and inhibiting differentiation into pro- inflammatory TH1 and TH17 cells while promoting anti-inflammatory iTreg and TH2 cell differentiation. Although these T cell phenotypes are important regulators of inflammatory demyelination, it has become increasing clear that B cells also play a critical role in MS. This is best exemplified by the potent activity of B cell depleting therapies in MS, such as the anti-CD20 monoclonal antibody ocrelizumab. B cells are unique in the immune system by having both innate and adaptive immune activity; the former exemplified by activation via Toll-like receptors (TLR) and antigen-presenting cell (APC) functions that trigger T cell responses. The mechanism of action of ocrelizumab appears to primarily result from reduced innate immune activity rather than altering antibody production, as ocrelizumab reduces T cell number but not antibody or plasma cell levels in the cerebral spinal fluid of treated MS patients. Here we test the hypothesis that N-glycan branching serves as a critical negative regulator of pro-inflammatory innate immune activity in B cells to suppress pro- inflammatory T cell responses and inflammatory demyelination. To evaluate this hypothesis, the following Aims are proposed. Aim 1 examines regulation of TLR4 and TLR2 responses by N-glycan branching in B cells. Aim 2 examines regulation of B cell receptor signaling by N-glycan branching. Aim 3 examines whether N- glycan branching in B cells suppresses inflammatory demyelination. Positive results will identify N-glycan branching as a major contributor to B cell mediated regulation of inflammatory demyelination and has implications for understanding the mechanism of action of B cell depleting therapies in MS.

抽象的 我们发表的工作表明，ASN（N）连接蛋白质糖基化的缺陷 减少小鼠的炎症性脱髓鞘，并与多发性硬化症（MS）有关。不足 在N-Glycan附着在蛋白质上的分支中，在实验中或通过自然遗传诱导 人类变异，促进T细胞介导的炎症性脱髓鞘和神经退行性。为了 例如，分支缺乏症在PL/J小鼠中引起自发且缓慢进行的MS样疾病， 其特征是炎症性脱髓鞘，轴突损伤和神经元死亡。机械上， 分支和每个蛋白质分子的N-聚糖数量合作以调节与甲状腺素的结合，14- 糖结合蛋白的成员家族。半乳糖素通过其附着的N-结合与细胞表面糖蛋白结合 聚糖，在细胞表面形成一个宏观分子晶格，该晶格控制分布，聚类和 表面糖蛋白的内吞作用以协调和可预测的方式。 n-聚糖明显分支 通过减少免疫的T细胞受体聚类/信号传导来抑制小鼠和人类的T细胞活性 突触，促进生长抑制剂CTLA-4的表面保留，并抑制分化为促进 炎症性Th1和Th17细胞，同时促进抗炎ITREG和Th2细胞分化。虽然 这些T细胞表型是炎症性脱髓鞘的重要调节剂，它变得越来越清晰 该B细胞在MS中也起着关键作用。最好通过B细胞耗尽的有效活性来说明这一点 MS中的疗法，例如抗CD20单克隆抗体ocrelizumab。 B细胞在免疫中是独特的 通过具有先天和适应性免疫活性的系统；前者通过Toll样激活来举例说明 受体（TLR）和抗原呈递细胞（APC）函数触发T细胞反应。机制 Ocrelizumab的作用似乎主要是由先天免疫活动降低而不是改变 抗体产生，如ocrelizumab会减少T细胞数，但不能减少抗体或浆细胞水平 经过治疗的MS患者的脑脊髓液。在这里，我们检验了n-聚糖分支作为用作的假设 B细胞中促炎的先天性免疫活性的关键负调节剂，以抑制促进 炎性T细胞反应和炎症性脱髓鞘。为了评估这一假设，以下 提出了目标。 AIM 1检查通过B细胞中N-聚糖分支对TLR4和TLR2响应的调节。 AIM 2检查通过N-聚糖分支对B细胞受体信号的调节。 AIM 3检查n-是否 B细胞中的聚糖分支抑制炎症性脱髓鞘。积极的结果将确定N-聚糖 作为B细胞介导的炎症性脱髓鞘调节的主要贡献者，并具有 了解MS中B细胞耗尽疗法的作用机理的意义。