Genetic Modulation of Blood and Vascular Glycosylation

描述(申请人提供)：糖链是细胞和细胞外分子的主要成分，其复杂性可与核酸和蛋白质相媲美。该计划继续关注位于细胞表面最外层的两种主要类型的阴离子多聚糖，即透明质酸(HA)、硫酸乙酰肝素(HS)和硫酸软骨素/皮肤素(CS/DS)的糖基化唾液酸(SIAS)和糖胺聚糖(GAG)链。很好地描述了血细胞和血浆糖蛋白的唾液酸化N-和O-糖链的结构。特定的糖结合蛋白识别这些SIAs，包括CD33相关的Siglecs(具有胞浆信号基序的L类型的凝集素，在特定的血细胞类型上)(项目2)。一些β-半乳糖苷特异性凝集素检测到与止血和免疫功能有关的蛋白质上某些SIAs的选择性缺失，从而影响它们的调节和周转(项目1)。HS和CS/DS蛋白多糖的GAG链调节内皮生物学中的多个过程，包括血管生成和白细胞迁移(项目3)。由特定的透明质酸酶产生的HA片段也可以连接模式检测受体，如TLRs(项目4)。大多数SIAs和GAG的生理和病理作用在培养细胞中并不明显，但必须在完整的生物体中探索--而哺乳动物多糖的这种复杂性在模型无脊椎动物中并没有得到很好的体现。因此，这项建议的中心主题是在小鼠中对SIAs、Gag链和它们的一些同源结合蛋白进行最先进的遗传操作。当系统基因失活模型无效或具有令人困惑的表型时，我们将选择性地灭活小鼠。基因以特定的细胞类型和发育调节的方式。在某些情况下，转基因基因的过度表达适用于回答特定的问题。这种方法允许特别关注血细胞、内皮和血浆蛋白的多聚糖和多聚糖结合蛋白。在过去的10年里，我们组建并维持了一个高度互动的专家团队，分析这种基因操作对止血、免疫和血管系统结构和功能的影响，重点是对血浆蛋白周转、血管生成和白细胞介导的免疫反应的功能影响。还出现了更多的智力和实际合作与协同增效的机会。这些研究将揭示多糖在健康和疾病中的许多重要功能。

DESCRIPTION (provided by applicant): Glycan chains are major components of cells and extracellular molecules, with a complexity rivalling that of nucleic acids and proteins. This program continues to focus on two major types of anionic glycans at the outermost aspects of the cell surface glycocalyx - Sialic Acids (Sias) and the Glycosaminoglycan (GAG) chains Hyaluronan (HA), Heparan sulfate (HS) and Chondrotin suflate/Dermatan sulfate (CS/DS). The structures of sialylated N- and O-glycans of blood cell and plasma glycoproteins are well described. Specific glycan-binding proteins differentially recognize these Sias, including CD33-related Siglecs (l-type lectins with cytosolic signaling motifs, on specific blood cell types) (Project 2). Some beta-galactoside-specific lectins detect the selective absence of certain Sias on proteins involved in hemostasis and immune function, affecting their regulation and turnover (Project 1). The GAG chains of HS and CS/DS proteoglycans regulate multiple processes in endothelial biology, including angiogenesis and leukocyte migration (Project 3). Fragments of HA generated by specific hyaluronidases can also ligate pattern detection receptors such as TLRs (Project 4). Most physiologic and pathological roles of Sias and GAGs are not evident in cultured cells, but must be explored in the intact organism - and this complexity of mammalian glycans is not well represented in model invertebrates. Thus, the central theme of this proposal is state-of-the-art genetic manipulation of Sias, GAG chains, and some of their cognate binding proteins in the mouse. When systemic gene inactivation models are non-viable or have confusing phenotypes, we will selectively inactivate mouse. genes in a cell type-specific and developmentally-regulated manner. In some instances, transgenic overexpression of genes is appropriate to answer specific questions. This approach allows a specific focus on glycans and glycan-binding proteins of blood cells, endothelium, and plasma proteins. Over the past 10 years, we have assembled and sustained a highly interactive team of experts to analyze the consequences of such genetic manipulations on the structure and function of hemostatic, immune and vascular systems, focusing on functional consequences on plasma protein turnover, angiogenesis, and the leukocyte-mediated immune responses. Many more opportunities for intellectual and practical collaborations and synergies have also emerged. These studies will reveal many important functions for glycans in health and disease.