Importance of N-glycosylation at the Neuromuscular Junction

N-糖基化在神经肌肉接头处的重要性

• 批准号: MR/S007180/1
• 负责人: Yin Yao Dong
• 金额: $ 162.75万
• 依托单位: University of Oxford
• 依托单位国家: 英国
• 项目类别: Fellowship
• 财政年份: 2019
• 资助国家: 英国
• 起止时间: 2019 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=MR%2FS007180%2F1
• 关键词: Importance; glycosylation; Neuromuscular; Junction

When someone asks you: "what do sugars do in our body?" What do you think of? Do you just think about them as a source of calories? Well sugars are much more than just a source of calories! They can form a great variety of intricate and complex structures called glycans, which play many important roles in our body. Some of the most important roles they play is in helping proteins assemble and function properly. Glycans are synthesised and transferred onto proteins in an enzymatic process called glycosylation, which is one of the most common and important post-translational processes that proteins undergo. However, protein glycosylation is poorly understood, with very little information available for most of the enzymes involved. We also don't know the biological roles of the vast majority of glycans.Glycosylation is essential to all complex life including plants, animals and fungi. This is exemplified by what happens when the glycosylation process malfunctions. Mutations in nearly all the genes involved in glycosylation can lead to developmental disorders, with a spectrum of symptoms and severity. In the most severe cases, patients have the multisystem disorder congenital disease of glycosylation (CDG), and can pass away within one year of birth, or even in utero. An intriguing group of patients have congenital myasthenic syndromes (CMS), with symptoms restricted to the abnormal development of neuromuscular junctions (NMJ), which are essential for communication between nerves and muscles, and have fatiguable muscle weakness. I aim to use the study of these cases to provide a window for understanding the more severe multisystem disorders. Around 1,000 patient families have been identified so far with mutations in glycosylation genes, with more found every year. There are very few treatment options for these patients, most of which only temporarily help alleviate symptoms, and are ineffective in the long term.This proposal aims to improve our understanding of glycosylation and the diseases associated with it, and has 3 main objectives: 1) Better understand the fundamental properties of the enzymes that are involved in the protein glycosylation pathway, and how mutations change these properties to bring about disease. 2) Identify the changes in the glycosylation of key NMJ glycoproteins in muscle cells obtained from CMS patients and healthy controls.3) Test therapeutic methods to correct the disease associated changes observed in the protein and cellular models of disease created in 1) and 2).To achieve these objectives, a multidisciplined approach will be employed combining cutting edge techniques in structural biology, biochemistry, molecular biology, cellular biology and glycomics. This research program will exploit the data gathered by the specialist genetics centres from the UK and around the world, maximising the benefits of modern genetics and sequencing technology to address fundamental questions in protein glycosylation, and the mechanisms underlying CMS and CDG. A biochemical and cellular platform will be created to test novel therapeutic approaches to treating glycosylation-associated CMS. The knowledge gained from this proposal will directly benefit CMS and CDG patients as well as the clinicians and scientists trying to help them. It will also benefit scientists from a variety of other fields including neuroscience, glycobiology, structural biology, and enzymology. My previous work in this area has already helped to develop novel antibiotics against the bacteria that causes tuberculosis. Glycans and glycoproteins are commonly used in medicines, therefore, information on their biosynthetic mechanisms will also have great benefits for the pharmaceutical and biotechnology industries.

当有人问你：“糖在我们体内起什么作用？”你觉得怎么样？你认为它们只是卡路里的来源吗？糖不仅仅是卡路里的来源！它们可以形成各种各样的错综复杂的结构，称为聚糖，在我们的身体中起着许多重要的作用。它们扮演的一些最重要的角色是帮助蛋白质组装和正常运作。糖基化是一种被称为糖基化的酶促过程，它被合成并转移到蛋白质上，这是蛋白质经历的最常见和最重要的翻译后过程之一。然而，对蛋白质糖基化的了解甚少，对大多数相关酶的信息很少。我们也不知道绝大多数聚糖的生物学作用。糖基化对包括植物、动物和真菌在内的所有复杂生命都是必不可少的。当糖基化过程发生故障时，就会发生这种情况。几乎所有参与糖基化的基因突变都可导致发育障碍，并伴有一系列症状和严重程度。最严重的患者为先天性糖基化多系统疾病（CDG），可在出生一年内死亡，甚至在子宫内死亡。一组有趣的患者患有先天性肌无力综合征（CMS），其症状局限于神经肌肉连接（NMJ）的异常发育，这是神经和肌肉之间的沟通所必需的，并且有疲劳性肌肉无力。我的目的是通过对这些病例的研究，为理解更严重的多系统疾病提供一个窗口。到目前为止，大约有1000个患者家庭被发现有糖基化基因突变，每年都有更多的人被发现。这些患者的治疗选择非常少，其中大多数只能暂时帮助缓解症状，长期无效。本提案旨在提高我们对糖基化及其相关疾病的理解，主要有3个目标：1)更好地了解参与蛋白质糖基化途径的酶的基本特性，以及突变如何改变这些特性从而导致疾病。2)鉴定CMS患者和健康对照肌细胞中关键NMJ糖蛋白的糖基化变化。3)测试治疗方法，以纠正在1)和2)中创建的疾病的蛋白质和细胞模型中观察到的与疾病相关的变化。为了实现这些目标，我们将采用多学科的方法，结合结构生物学、生物化学、分子生物学、细胞生物学和糖组学的前沿技术。该研究计划将利用来自英国和世界各地的专业遗传学中心收集的数据，最大限度地利用现代遗传学和测序技术来解决蛋白质糖基化的基本问题，以及CMS和CDG的潜在机制。将创建一个生化和细胞平台来测试治疗糖基化相关CMS的新治疗方法。从该提案中获得的知识将直接受益于CMS和CDG患者以及试图帮助他们的临床医生和科学家。它也将使其他领域的科学家受益，包括神经科学、糖生物学、结构生物学和酶学。我之前在这一领域的工作已经帮助开发了对抗导致结核病的细菌的新型抗生素。聚糖和糖蛋白在药物中是常用的，因此，了解它们的生物合成机制对制药和生物技术行业也有很大的好处。

项目成果

260th ENMC International Workshop: Congenital myasthenic syndromes 11-13 March 2022, Hoofddorp, The Netherlands

• DOI: 10.1016/j.nmd.2022.12.006
• 发表时间: 2023-09-01
• 期刊: NEUROMUSCULAR DISORDERS
• 影响因子: 2.8
• 作者: Spendiff，Sally;Dong，Yin;Lochmueller，Hanns
• 通讯作者: Lochmueller，Hanns

Predominant and novel de novo variants in 29 individuals with ALG13 deficiency: Clinical description, biomarker status, biochemical analysis, and treatment suggestions.

• DOI: 10.1002/jimd.12290
• 发表时间: 2020-11
• 期刊: Journal of inherited metabolic disease
• 影响因子: 4.2
• 作者: Ng BG;Eklund EA;Shiryaev SA;Dong YY;Abbott MA;Asteggiano C;Bamshad MJ;Barr E;Bernstein JA;Chelakkadan S;Christodoulou J;Chung WK;Ciliberto MA;Cousin J;Gardiner F;Ghosh S;Graf WD;Grunewald S;Hammond K;Hauser NS;Hoganson GE;Houck KM;Kohler JN;Morava E;Larson AA;Liu P;Madathil S;McCormack C;Meeks NJL;Miller R;Monaghan KG;Nickerson DA;Palculict TB;Papazoglu GM;Pletcher BA;Scheffer IE;Schenone AB;Schnur RE;Si Y;Rowe LJ;Serrano Russi AH;Russo RS;Thabet F;Tuite A;Villanueva MM;Wang RY;Webster RI;Wilson D;Zalan A;Undiagnosed Diseases Network, University of Washington Center for Mendelian Genomics (UW-CMG);Wolfe LA;Rosenfeld JA;Rhodes L;Freeze HH
• 通讯作者: Freeze HH