Human siglec ligands control mast cell and eosinophil mediated inflammation

人siglec配体控制肥大细胞和嗜酸性粒细胞介导的炎症

• 批准号: 10097998
• 负责人: RONALD L SCHNAAR
• 金额: $ 51万
• 依托单位: NORTHWESTERN UNIVERSITY AT CHICAGO
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-02-06 至 2023-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10097998
• 关键词: Allergic; Allergic Disease; Allergic inflammation; Anabolism; Apoptosis; Avidity; Binding; Biological Response Modifiers; Bronchi; Carrier Proteins; Cell Line; Cell surface; Cells; Characteristics; Chronic; Data; Disease; Drug or chemical Tissue Distribution; Duct (organ) structure; Enzymes; Family; Family member; Future; Gastrointestinal tract structure; Gene Expression; Gland; Goals; Health; Histologic; Human; Human Activities; ITIM; Immune; In Vitro; Individual; Inflammation; Inflammatory; Intestines; Keratan Sulfate; Knowledge; Lead; Leukocytes; Ligand Binding Domain; Ligands; Link; Mediating; Methods; Molecular; Mucous body substance; Polysaccharides; Proteoglycan; Regulation; Sialic Acids; Signaling Molecule; Skin; Specificity; Structure; Structure-Activity Relationship; Sulfate; Techniques; Technology; Testing; Therapeutic Intervention; Tissues; Trachea; base; eosinophil; extracellular; granulocyte; human tissue; immunoregulation; in vivo; inhibitor/antagonist; insight; mast cell; member; new therapeutic target; overexpression; receptor; sialic acid binding Ig-like lectin; sulfotransferase; therapeutic target

Inflammation is resolved, in part, by cell surface signaling molecules on leukocytes that have extracellular ligand binding domains linked to intracellular immune inhibitory domains. Among these are members of the siglec family that have ITIM and ITSM inhibitory sequences on their short intracellular domains that are actuated when they bind, with high specificity, to extracellular sialoglycans (siglec ligands) expressed on inflammatory target tissues. Project 3 is based on the hypothesis that endogenous human siglec ligands are multivalent sialoglycans produced by inflammatory target tissues including airway, skin and intestine. In terms of allergic inflammation, Siglec-8 is expressed on human eosinophils, whereas CD33 (Siglec-3), Siglec-6 and Siglec-8 are expressed by mast cells. When siglecs on these granulocytes encounter their sialoglycan ligands, inflammation is halted; engagement of Siglec-8 on eosinophils results in their apoptosis whereas engagement of siglecs on mast cells inhibits immune mediator release. We propose that identification of immune inhibitory sialoglycan structures and knowledge of how their expression is regulated in health and disease will provide new insights into the molecular basis of immune regulation and perhaps new targets for therapeutic intervention in human allergic inflammation. Three aims are proposed to accomplish these goals. Aim 1 is based on our finding that Siglec-8 ligands on human airway are robustly expressed in submucosal glands and ducts, and that these ligands are secreted onto the airway mucus layer. This aim will compare Siglec-8 sialoglycan ligands in mucus secretions from inflamed and non-inflamed human airways, revealing quantitative as well as qualitative (protein carrier, glycan structure) information. Our studies on airway Siglec-8 ligands will be extended to other human tissues subject to allergic inflammation, using healthy and inflamed human skin and GI tract. Tissue distributions and molecular characteristics of Siglec-8 ligands will be compared among these tissues. Aim 2 will explore the glycan structures required for optimal Siglec-8 engagement on eosinophils and mast cells. Based on our finding that specifically sulfated and sialylated keratan sulfate chains are responsible for Siglec-8 binding on human airways, we will use chemoenzymatic methods to generate modified glycan structures to test for binding requirements. We will create multivalent forms of these ligands to functionally engage Siglec-8 on human eosinophils and mast cells. The knowledge gained will be used to identify glycan biosynthetic enzymes that, when transfected into human submucosal gland cell lines, result in expression of Siglec-8 ligands. Concurrently, in Aim 3, we will apply the technologies we established to identify Siglec-8 ligands to the search for endogenous human ligands for CD33 and Siglec-6. Through these aims we anticipate significantly enhancing our understanding of glycans involved in regulating allergic inflammation and their expression in health and disease.

炎症部分是通过白细胞上的细胞表面信号分子来解决的， 与细胞内免疫抑制结构域连接的配体结合结构域。其中包括 在其短胞内结构域上具有ITIM和ITSM抑制序列siglec家族， 当它们以高特异性结合细胞外唾液酸聚糖（siglec配体）时被激活， 炎症靶组织。项目3基于内源性人siglec配体 是由包括气道、皮肤和肠的炎症靶组织产生的多价唾液聚糖。 就过敏性炎症而言，Siglec-8在人嗜酸性粒细胞上表达，而CD 33（Siglec-3）， Siglec-6和Siglec-8由肥大细胞表达。当这些粒细胞上的信号细胞遇到它们的 唾液酸聚糖配体，炎症停止; Siglec-8与嗜酸性粒细胞的结合导致其炎症反应。 细胞凋亡，而肥大细胞上的SIGLECs的参与抑制免疫介质释放。我们提出 免疫抑制性唾液酸聚糖结构的鉴定和它们的表达如何被 调节健康和疾病将提供新的见解免疫调节的分子基础 并且可能是人类过敏性炎症治疗干预的新靶点。 为了实现这些目标，提出了三个目标。目的1是基于我们发现Siglec-8配体 人气道上的配体在粘膜下腺体和导管中稳健表达，并且这些配体是 分泌到气道粘液层上。该目的将比较粘液中的Siglec-8唾液酸聚糖配体 炎症和非炎症人类气道的分泌物，揭示定量和定性 （蛋白质载体、聚糖结构）信息。我们对气道Siglec-8配体的研究将扩展到 使用健康和发炎的人体皮肤和胃肠道，对其他易受过敏性炎症影响的人体组织进行检测。 将比较这些组织中Siglec-8配体的组织分布和分子特征。 组织中目的2将探索Siglec-8最佳结合嗜酸性粒细胞所需的聚糖结构 和肥大细胞。基于我们的发现，特异性硫酸化和唾液酸化硫酸角质素链是 负责Siglec-8在人气道上的结合，我们将使用化学酶促方法来产生Siglec-8。 修饰聚糖结构以测试结合要求。我们将创造出这些的多价形式 在一些实施方案中，Siglec-8配体与人嗜酸性粒细胞和肥大细胞上的Siglec-8功能接合。获得的知识将 用于鉴定聚糖生物合成酶，当转染到人粘膜下腺细胞中时， 细胞系，导致Siglec-8配体的表达。同时，在目标3中，我们将应用我们 建立了用于鉴定Siglec-8配体以寻找⑶ 33和Siglec-6的内源性人配体的方法。 通过这些目标，我们预计将大大提高我们对聚糖的理解， 调节过敏性炎症及其在健康和疾病中的表达。