Mechanisms of human immune modulation by oral N-acetylglucosamine

描述(申请人提供)：我们在小鼠身上发表的数据显示，单糖和膳食补充剂N-乙酰氨基葡萄糖(GlcNAc)通过增强T细胞中的N-糖基化来抑制T细胞功能和自身免疫。事实上，后生动物的所有细胞表面和分泌的蛋白质都是通过在内质网/高尔基体分泌途径中添加复杂的碳水化合物来修饰的，提供了大量不被基因组编码的分子信息。我们发现高尔基体N-糖基化的遗传、代谢和环境调节控制着细胞表面的大分子复合体，从而影响细胞的生长、分化和疾病状态。每个蛋白质分子的支链和N-糖链的数量共同调节与Galectins的结合，形成Galectin-糖蛋白晶格，以可预测的方式控制表面糖蛋白的分布、聚集和内吞。N-葡聚糖分支缺陷通过增强T细胞受体聚集/信号传递，减少生长抑制物的表面滞留，诱导小鼠T细胞高活性和自发性自身免疫性疾病 CTLA-4和转化生长因子-B受体RI/II，并促进分化为促炎的TH1/TH17细胞。在人类中，多发性硬化症(MS)的多种遗传和环境危险因素汇聚在一起，导致N-糖基化和CTLA-4表面滞留的失调。包括白介素7受体α、白介素2受体α、MGAT1、MGAT5和CTLA-4的遗传变异，以及维生素D3和代谢产物UDP-GlcNAc，MGAT1和MGAT5的底物。通过补充N-乙酰氨基葡萄糖(GlcNAc)通过代谢增加UDP-GlcNAc来挽救体外和体内T细胞的N-糖链分支缺陷，抑制T细胞的生长，增强CTLA-4和转化生长因子-βRI/II的表面表达，阻断TH1/TH17的分化，抑制MS和自身免疫性糖尿病模型，并挽救由MS遗传危险因素引起的N-糖链分支缺陷。使用GlcNAc对N-糖链生物合成进行治疗性补充，可能会提供一种个性化的药物途径，以抑制促进人类自身免疫的潜在分子缺陷。在这里，我们建议研究人类口服GlcNAc是否增强N-糖链分支以抑制T细胞功能和诱导免疫偏离，重点关注具有促进多发性硬化和下调T细胞N-糖链分支的遗传多态的个体。特异性目的1研究GlcNAc是否在体外调节男性和女性人类T细胞中N-糖链的低形态分支，以抑制前自身免疫的TH1/TH17细胞，同时增强抗自身免疫的T调节细胞。特定目的2检查口服GlcNAc是否增强N-糖链分支以抑制前自身免疫TH1/TH17反应，同时增强N-糖基化遗传缺陷的MS患者的抗自身免疫T调节细胞。

DESCRIPTION (provided by applicant): Our published data in mice has revealed that the simple sugar and dietary supplement N- acetylglucosamine (GlcNAc) inhibits T cell function and autoimmunity by enhancing N-glycosylation in T cells. Virtually all cell surface and secreted proteins in metazoans are modified by the addition of complex carbohydrates in the ER/Golgi secretory pathway, imparting substantial molecular information not encoded by the genome. We find that genetic, metabolic and environmental regulation of Golgi N-glycosylation controls macromolecular complexes on the cell surface to influence cell growth, differentiation and disease states. The branching and number of N-glycans per protein molecule cooperate to regulate binding to galectins, forming a galectin-glycoprotein lattice that controls the distributin, clustering and endocytosis of surface glycoproteins in a predictable manner. N-glyan branching deficiency induces T cell hyper-activity and spontaneous autoimmune disease in mice by enhancing T cell receptor clustering/signaling, reducing surface retention of the growth inhibitors CTLA-4 and TGF-ßRI/II and promoting differentiation into pro-inflammatory TH1/TH17 cells. In humans, multiple genetic and environmental risk factors for Multiple Sclerosis (MS) converge to dysregulate N- glycosylation and CTLA-4 surface retention. These include genetic variants in interleukin-7 receptor-α, interleukin-2 receptor-α, MGAT1, MGAT5 and CTLA-4 as well as Vitamin D3 and metabolic production of UDP-GlcNAc, the substrate for MGAT1 and MGAT5. Rescuing N-glycan branching deficiency in T cells in vitro and in vivo by metabolically increasing UDP-GlcNAc with the dietary supplement N-acetylglucosamine (GlcNAc), suppresses T cell growth, enhances CTLA-4 and TGF-ßRI/II surface expression, blocks TH1/TH17 differentiation, inhibits MS and autoimmune diabetes models and rescues N-glycan branching deficiency induced by MS genetic risk factors. Therapeutic supplementation to N-glycan biosynthesis with GlcNAc may provide a personalized medicine approach to suppress an underlying molecular defect promoting human autoimmunity. Here we propose to examine whether oral GlcNAc in humans enhances N-glycan branching to suppress T cell function and induce immune deviation, focusing on individuals with genetic polymorphisms that promote MS and down-regulate N-glycan branching in T cells. Specific Aim 1 examines whether in vitro GlcNAc regulates hypomorphic N-glycan branching in male vs female human T cells to suppress pro- autoimmune TH1/TH17 cells while enhancing anti-autoimmune T regulatory cells. Specific Aim 2 examines whether oral GlcNAc enhances N-glycan branching to suppress pro-autoimmune TH1/TH17 responses while enhancing anti-autoimmune T regulatory cells in MS patients with genetic defects in N-glycosylation.