New Congenital Disorders of Glycosylation: Therapy and Models

描述(申请人提供)：许多先天性糖基化紊乱(CDG)患者在40个已知缺陷基因中没有突变。我们将在患者中鉴定出7个新的CDG，并在他们的细胞中从功能上证实它们，并在斑马鱼身上建立一些缺陷的模型。一名患者正在进行简单的甘露糖治疗，我们将测试来自其他有相同缺陷的患者的细胞，或在其他需要甘露糖治疗的步骤中进行潜在的治疗。我们将鉴定甘露糖选择性质膜转运蛋白和高尔基体定位的UDP-半乳糖转运蛋白。候选缺陷基因将通过新开发的细胞生物标记物进行确认，以监测患者的低糖基化情况，并通过cDNA互补或甘露糖治疗进行纠正。之前使用CDG的两个斑马鱼模型的研究表明，它们模仿糖基化缺陷的表型，其中一个对甘露糖治疗有反应。我们的患者组在两个寡糖基转移酶(OST)复合体基因、两个与OST相关的TRAP复合体基因、一个假定的甘露糖转运体、一个已知的UDP-Gal转运体和一个假定的苯二醇代谢基因中存在Sanger确认的突变。令人惊讶的是，CDG病例中有已知的病理基因ALG1突变。这些患者会产生一种意想不到的生物标志物--葡聚糖。引人注目的是，甘露糖疗法减少了患者细胞或血清中这种标志性多糖的数量，似乎改善了一名患者的神经病理。其他患者可能受益于无毒的甘露糖疗法，可能是通过甘露糖转运蛋白(S)。在AIM1中，我们将验证这些新的先天性糖基化紊乱。在AIM 2中，选定的疾病将在斑马鱼变种中模拟，用于表型和生化分析。目标3将确定人类甘露糖优先转运蛋白(S)和新的高尔基UDP-半乳糖转运蛋白。甘露糖和半乳糖疗法可以用于斑马鱼模型，也可能用于这些患者。一种新的ALG1特异性血清生物标记物的戏剧性出现将重点放在非天然多糖的基础上，并识别可能对甘露糖治疗有反应的患者。有证据表明，患有其他10种CDG缺陷的患者也可能对甘露糖治疗有反应。这强调了在其他患者身上尝试简单疗法的紧迫性。当这个项目完成后，CDG患者和基础科学都将受益。

DESCRIPTION (provided by applicant): Many patients with Congenital Disorders of Glycosylation (CDG) do not have mutations in the 40 known defective genes. We will identify 7 new CDGs in patients and functionally confirm them in their cells and model some defects in zebrafish. Simple mannose therapy is ongoing in one patient and we will test cells from other patients with the same defect or defects in other mannose-requiring steps as a potential treatment. We will identify mannose-selective plasma membrane transporters and Golgi-located UDP-Galactose transporters. Candidate defective genes will be confirmed with newly developed cellular biomarkers to monitor patients' hypo-glycosylation and correction with cDNA complementation or mannose therapy. Previous work using two zebrafish models of CDG show they mimic glycosylation-deficient phenotypes and one responds to mannose therapy. Our group of patients has Sanger-confirmed mutations in two oligosaccharyl-transferase (OST) complex genes, two in the OST-associated TRAP complex genes, in a putative mannose transporter, a known UDP-Gal transporter, and a putative dolichol metabolism gene. A surprisingly high number of CDG cases have mutations in a known pathological gene, ALG1. These patients make an unanticipated biomarker glycan. Strikingly, mannose therapy reduces the amount of that marker glycan in patient cells or serum and appears to improve one patient's neurological pathology. Other patients may benefit from non-toxic mannose therapy, presumably delivered through mannose transporter(s). In AIM1 we will verify these new Congenital Disorders of Glycosylation. In AIM 2, selected disorders will be modeled in zebrafish morphants for phenotypic and biochemical analysis. AIM 3 will identify human Mannose- preferential transporter(s) and novel Golgi UDP-Gal Transporters. Mannose and galactose therapies may be used in the zebrafish models and possibly in these patients. The dramatic appearance of a new ALG1-specific serum biomarker focuses AIM 4 on the basis of non-natural glycan and identifying patients who might respond to mannose therapy. Evidence suggests that patients with 10 other CDG defects may also respond to mannose therapy. This emphasizes the urgency of trying a simple therapy on other patients. Both CDG patients and basic science will benefit when this project is completed.