A novel role for p53 in congenital disorders of glycosylation

描述（由候选人提供）：患有罕见的先天性糖基化疾病（CDG）的儿童在N-连接蛋白糖基化所需的许多基因之一中发生突变，有38种不同的亚型，37种没有治疗选择。甘露糖-6-磷酸异构酶（MPI）突变导致“胃肠道型”CDG。目前尚不清楚CDG患者中脂联寡糖（LLO）的合成缺陷如何导致多系统异常，并且存在少数CDG动物模型。斑马鱼提供了一个强大的脊椎动物系统来研究单基因疾病，其对人类的高度遗传保守性，而吗啉代提供了快速有效的基因敲除。我使用吗啉代技术来建立具有小于15%的残余Mpi酶活性的mpi吗啉代。他们在头部，眼睛，肠道，肝脏和身体形状方面出现缺陷，并增加受影响组织的细胞死亡。MPI-CDG是唯一一种已知治疗的CDG：口服甘露糖增加通过己糖激酶的流量，以及产生甘露糖-6-磷酸并使蛋白质糖基化正常化的次要补充代谢途径，从而缓解大多数症状。类似地，mpi变体中的形态和细胞死亡表型几乎完全被甘露糖补充拯救。我的初步数据在一个新的斑马鱼模型MPI-CDG牵连激活的肿瘤抑制因子，p53，在CDG病理。我们的目的是确定是否众所周知的肿瘤抑制因子，p53，在MPI-CDG的疾病机制中具有新的作用。我们的中心假设是p53是MPI-CDG疾病的原因，并将确定p53影响糖基化或凋亡代谢改变的机制。具体目的：1：建立p53激活、甘露糖代谢和Mpi缺乏之间的关系。2：确定MPI-CDG是否是异常LLO或糖蛋白形成的结果。3：确定p53介导的细胞凋亡对mpi morphant表型的贡献。我的长期目标是了解CDG的分子基础，重点是相关的胃肠道疾病。CDG潜在的遗传缺陷很简单，也很容易理解。然后，我将把这些知识应用于儿科患者中这些相同疾病的更常见原因，因为非酒精性脂肪肝，纤维化和肝硬化都与蛋白质糖基化缺陷有关。

DESCRIPTION (provided by Candidate): Children with the rare congenital disorders of glycosylation (CDG) have a mutation in one of the many genes required for N-linked protein glycosylation and of 38 distinct subtypes, 37 have no treatment options. Mutation of mannose-6-phosphate isomerase (MPI) causes the "gastrointestinal type" of CDG. It is not understood how defective synthesis of the lipid-linked oligosaccharide (LLO) in CDG patients results in multi-systemic abnormalities and few CDG animal models exist. zebrafish provide a powerful vertebrate system to study monogenic disorders with their high genetic conservation to humans, and morpholinos offer rapid and efficient gene knockdown. I used morpholino technology to establish mpi morphants with less than 15% residual Mpi enzyme activity. They develop defects in the head, eye, gut, liver, and body shape with increased cell death in affected tissues. MPI-CDG is the only CDG with a known treatment: oral mannose increases flux through hexokinase and a minor complementary metabolic pathway that produces mannose-6-phosphate and normalizes protein glycosylation, relieving most symptoms. Similarly, both the morphologic and cell death phenotype in mpi morphants are almost completely rescued by mannose supplementation. My preliminary data in a novel zebrafish model of MPI-CDG implicate activation of the tumor suppressor, p53, in CDG pathology. Our objective is to determine whether the well known tumor suppressor, p53, has a novel role in the mechanism of disease in MPI-CDG. Our central hypothesis is that p53 is responsible for disease in MPI-CDG and will determine the mechanism by which p53 affects either metabolic alterations in glycosylation or apoptosis. Specific Aims: 1: Establish the relationship between p53 activation, mannose metabolism, and Mpi deficiency. 2: Determine whether MPI-CDG is a result of abnormal LLO or glycoprotein formation. 3: Determine the contribution of p53-mediated apoptosis to the mpi morphant phenotype. My long-term goal is to understand the molecular basis of CDG with a focus on the associated gastrointestinal disorders. The underlying genetic defect in CDG is simple and well understood. I will then apply this knowledge to more common causes of these same diseases in pediatric patients, as non-alcoholic fatty liver disease, fibrosis, and cirrhosis are all associated with defects in protein glycosylation.