Genetic Modulation of Blood and Vascular Glycosylation

描述（由申请人提供）：聚糖链是细胞和细胞外分子的主要组分，其复杂性可与核酸和蛋白质相媲美。该计划继续关注细胞表面糖萼最外层的两种主要类型的阴离子聚糖-唾液酸（Sias）和糖胺聚糖（GAG）链Hyglonan（HA）、硫酸乙酰肝素（HS）和硫酸软骨素/硫酸皮肤素（CS/DS）。血细胞和血浆糖蛋白的唾液酸化N-和O-聚糖的结构已得到充分描述。特异性聚糖结合蛋白差异识别这些Sias，包括CD 33相关Siglecs（具有细胞溶质信号传导基序的l型凝集素，在特定血细胞类型上）（项目2）。一些β-半乳糖苷特异性凝集素检测参与止血和免疫功能的蛋白质上某些Sias的选择性缺失，影响其调节和周转（项目1）。HS和CS/DS蛋白聚糖的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）。由特异性透明质酸酶产生的HA片段也可以连接模式检测受体，如TLR（项目4）。Sias和GAG的大多数生理和病理作用在培养的细胞中并不明显，但必须在完整的生物体中探索-并且哺乳动物聚糖的这种复杂性在模型无脊椎动物中没有得到很好的体现。因此，该提案的中心主题是对小鼠中的Sias、GAG链及其一些同源结合蛋白进行最先进的遗传操作。当系统性基因失活模型不能存活或具有混乱的表型时，我们将选择性地对小鼠进行失活。以细胞类型特异性和发育调节的方式表达基因。在某些情况下，基因的转基因过表达适合于回答特定的问题。这种方法允许特别关注血细胞、内皮和血浆蛋白的聚糖和聚糖结合蛋白。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，以分析这种遗传操作对止血，免疫和血管系统的结构和功能的影响，重点是对血浆蛋白质周转，血管生成和白细胞介导的免疫反应的功能性后果。还出现了更多的智力和实践合作与协同增效的机会。这些研究将揭示聚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.