Mechanisms of human immune modulation by oral N-acetylglucosamine

描述（由申请人提供）：我们在小鼠中发表的数据表明，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，后生动物中的所有细胞表面和分泌蛋白都通过在 ER/高尔基体分泌途径中添加复合碳水化合物进行了修饰，从而传递了基因组未编码的大量分子信息。我们发现高尔基体N-糖基化的遗传、代谢和环境调节控制细胞表面的大分子复合物，从而影响细胞生长、分化和疾病状态。每个蛋白质分子的 N-聚糖的分支和数量共同调节与半乳糖凝集素的结合，形成半乳糖凝集素-糖蛋白晶格，以可预测的方式控制表面糖蛋白的分布、聚集和内吞作用。 N-聚糖分支缺陷通过增强 T 细胞受体聚集/信号传导、减少生长抑制剂的表面保留，诱导小鼠 T 细胞过度活跃和自发性自身免疫性疾病 CTLA-4 和 TGF-ßRI/II 并促进分化为促炎性 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共同导致 N-糖基化和 CTLA-4 表面滞留失调。其中包括白细胞介素 7 受体 α、白细胞介素 2 受体 α、MGAT1、MGAT5 和 CTLA-4 的遗传变异，以及维生素 D3 和 UDP-GlcNAc（MGAT1 和 MGAT5 的底物）的代谢产生。通过膳食补充剂 N-乙酰氨基葡萄糖 (GlcNAc) 代谢增加 UDP-GlcNAc，在体外和体内挽救 T 细胞中的 N-聚糖分支缺陷，抑制 T 细胞生长，增强 CTLA-4 和 TGF-βRI/II 表面表达，阻断 TH1/TH17 分化，抑制 MS 和自身免疫性糖尿病模型，并挽救 MS 遗传危险因素引起的 N-聚糖分支缺陷。用 GlcNAc 对 N-聚糖生物合成进行治疗性补充可能会提供一种个性化医疗方法，以抑制促进人类自身免疫的潜在分子缺陷。 在这里，我们建议检查人类口服 GlcNAc 是否会增强 N-聚糖分支以抑制 T 细胞功能并诱导免疫偏差，重点关注具有促进 MS 和下调 T 细胞中 N-聚糖分支的遗传多态性的个体。具体目标 1 检查体外 GlcNAc 是否调节男性与女性人类 T 细胞中的亚形 N-聚糖分支，以抑制促自身免疫 TH1/TH17 细胞，同时增强抗自身免疫 T 调节细胞。具体目标 2 检查口服 GlcNAc 是否增强 N-聚糖分支以抑制促自身免疫 TH1/TH17 反应，同时增强具有 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.