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调节人类发育、免疫和疾病的信号传导过程。目前的建议旨在发展基于计算和实验方法的系统生物学，以增强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理解调节人类白细胞上o链聚糖形成的特征。通过结合属于选择家族的粘附分子，这些o -聚糖在调节白细胞粘附在炎症和心血管疾病部位血管壁上的血管内皮细胞中发挥关键作用。我们的总体假设是“糖基化反应网络的计算机建模可以识别控制人类白细胞上选择配体形成的限速步骤。这些限速步骤的明确和特定的扰动可以减少炎症期间体内白细胞-内皮细胞的粘附/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)量化选择的糖基转移酶和肽骨架在调节o -链糖基化和白细胞选择结合功能中的作用。3)检测糖基转移酶沉默对骨髓白细胞滞留和细胞向炎症部位迁移的影响。该项目涉及在系统生物学建模、定量生物工程实验、蛋白质组学、糖生物学、免疫学和动物模型方面具有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，到碳水化合物结构和细胞粘附功能，在体外和体内都有。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。预期的项目成果包括：I)定义一个名为GlycoML的新标准，用于描述糖基化反应网络。ii)结合实验和理论揭示糖基化的潜在细胞内/代谢靶点，这些靶点可以定量和明确地改变选择配体结构。iii)定义精确的a（2,3）唾液基转移酶(s)和a（1,3）聚焦转移酶(s)，调节人类白细胞中选择配体的生物合成。iv)提高了对肽主链在调节o -糖基化链起始、延伸和终止中的作用的认识。v)在炎症、腹膜炎和慢性阻塞性肺疾病（COPD）的动物模型中进行验证，通过计算机模拟和离体实验产生关键假设。

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.