Systems Biology of Glycosylation

描述（由申请人提供）：糖基化是蛋白质和脂质的重要翻译后修饰。这个过程控制着细胞识别和信号传导过程，调节人类发育，免疫力和疾病。目前的建议旨在开发基于系统生物学的计算和实验方法，以提高我们对细胞糖基化途径的理解。特别是，我们的重点是更好地了解功能，调节人白细胞上的O-连接聚糖的形成。通过结合属于选择性家族的粘附分子，这些0-聚糖在调节白细胞粘附于血管内皮细胞中起关键作用，所述血管内皮细胞在炎症和心血管疾病部位衬在血管壁上。我们的总体假设是，“糖基化反应网络的计算机模拟可以识别控制人类白细胞上选择素配体形成的限速步骤。这些限速步骤的定义和特定扰动可以减少炎症期间体内白细胞-内皮细胞粘附/迁移。“具体目标是：1）开发计算模型来预测控制细胞糖基化的限速步骤。2)量化所选糖基转移酶和肽骨架在调节O-连接糖基化和白细胞选择结合功能中的作用。3)检测沉默糖基转移酶对骨髓中白细胞滞留和细胞迁移至炎症部位的影响。该项目涉及具有系统生物学建模，定量生物工程实验，蛋白质组学，糖生物学，免疫学和动物模型专业知识的研究人员之间的合作。实验研究跨越多个尺度，从基因到蛋白质/酶，再到碳水化合物结构和细胞粘附功能，包括体外和体内。计算机建模整合了这些信息，以确定系统扰动对聚糖结构和功能的影响。预期项目成果包括：I）定义一个称为GlycoML的新标准，用于描述糖基化反应网络。ii）结合使用实验和理论来揭示糖基化的潜在细胞内/代谢靶点，其可以定量地和明确地改变选择素-配体结构。iii）精确定义调节人白细胞中选择素-配体生物合成的α（2，3）唾液酸转移酶和α（1，3）岩藻糖基转移酶。iv）提高对肽骨架在调节0-糖基化链起始、延伸和终止中的作用的理解。v）在炎症、腹膜炎和COPD（慢性阻塞性肺病）的动物模型中的验证，使用计算机模拟和离体实验产生的关键假设。

DESCRIPTION (provided by applicant): Glycosylation is an important post-translational modification of proteins and lipids. This process controls cell recognition and signaling processes that regulate human development, immunity and disease. The current proposal aims to develop Systems Biology based computational and experimental methodologies to enhance our understanding of cellular glycosylation pathways. In particular, our focus is on better understanding the features that regulate the formation of O-linked glycans on human leukocytes. By binding adhesion molecules belonging to the selecting family, these O-glycans play a critical role in regulating leukocyte adhesion to vascular endothelial cells that line blood vessel walls at sites of inflammation and cardiovascular disease. Our overall hypothesis is that "In silico modeling of glycosylation reaction networks can identify rate limiting steps that control the formation of selectin-ligands on human leukocytes. Defined and specific perturbation of these rate-limiting steps can reduce leukocyte-endothelial cell adhesion/migration in vivo during inflammation." The specific aims are: 1) to develop computational models to predict the rate-limiting steps that control cellular glycosylation. 2) To quantify the role of selected glycosyltransferases and the peptide backbone in regulating O-linked glycosylation and leukocyte selecting-binding function. 3) To test the effect of silencing glycosyltransferases on leukocyte retention in the bone marrow, and cell migration to sites of inflammation. The project involves collaboration between investigators with expertise in Systems Biology based modeling, quantitative bioengineering experimentation, proteomics, glycobiology, immunology and animal models. Experimental studies span multiple scales from genes, to proteins/enzymes, to carbohydrate structure and cell adhesion function, both in vitro and in vivo. The computer modeling integrates this information to determine the effect of system perturbation on glycan structure and function. Expected project outcomes include: I) Definition of a new standard called GlycoML for the description of glycosylation reaction networks. ii) Combined use of experiment and theory to reveal potential intra-cellular/metabolic targets of glycosylation that can quantitatively and definitively alter selectin-ligand structures. iii) Definition of the precise a (2, 3)sialyltransferase(s) and a (1, 3) fucosyltransferases(s) that regulate selectin-ligand biosynthesis in human leukocytes. iv) Improved understanding of the role of the peptide backbone in regulating O-glycosylation chain initiation, extension and termination. v) Validation in animal models of inflammation, peritonitis and COPD (chronic obstructive pulmonary disease), key hypothesis generated using computer simulation and ex vivo experimentation.