Chemokine CXCL17 and Mucosal Immunosurveillance

趋化因子 CXCL17 和粘膜免疫监视

基本信息

批准号：
8519289
负责人：
Krishna Rajarathnam
金额：
$ 21.57万
依托单位：
UNIVERSITY OF TEXAS MED BR GALVESTON
依托单位国家：
美国
项目类别：
财政年份：
2012
资助国家：
美国
起止时间：
2012-08-01 至 2015-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8519289
关键词：
Adopted Affinity Agonist Antigen-Presenting Cells Binding Biological Assay Breathing CX3CL1 gene CXCL12 gene Cell physiology Cells Characteristics Charge Chemotaxis Cysteine Dendritic Cells Dimerization Disulfides Eating Glycosaminoglycans Grant Heparin Homeostasis Human Immune Immune response Immunologic Monitoring Immunology In Vitro Inflammatory Knowledge Leukocytes Link Lung Mediating Modeling Mucous Membrane Mus Mutation N-terminal NMR Spectroscopy Organ Pattern Play Population Process Property Protein Chemistry Qualifying Receptor Activation Recruitment Activity Reporting Research Resolution Respiratory System Respiratory tract structure Role Sentinel Sequence Analysis Small Intestines Solutions Stomach Structure T-Lymphocyte Techniques Testing Tissues Virus Diseases arginyllysine base cell motility chemokine design disulfide bond experience in vivo insight migration monocyte novel pathogen receptor sedimentation equilibrium spatiotemporal three dimensional structure trafficking

项目摘要

DESCRIPTION (provided by applicant): CXCL17, a recently discovered chemokine, is constitutively expressed in mucosal tissues such as lung, stomach, and the small intestines. These organs are continuously exposed to a wide variety of pathogens via food intake and breathing, and so must be on high alert to mount a rapid and efficient immune response. CXCL17 could play an important role in this process, as it selectively recruits immature dendritic cells (DCs). These cells play a key role as immunological sentinels, and are professional antigen-presenting cells, and key regulators of T cell functions. Currently nothing is known about how CXCL17 mediates its in vivo functions. Characteristic features of chemokines are that they adopt the same three-dimensional structure, have four conserved cysteines that form two disulfide bonds, and bind glycosaminoglycans (GAGs). Both the disulfides are essential for receptor activation, and GAG binding is critical for directed migration of leukocytes. Most remarkably, sequence analysis reveals that CXCL17, has only three of the four conserved cysteines, and so may not adopt the typical chemokine structure; it also has a distinctly different distribution of positively charged residues, suggesting a novel GAG-binding mechanism. Another unusual feature of CXCL17 is that it is active only at high concentrations, and shows optimal activity at 100-1000x higher concentrations than is normally observed for most chemokines (?M vs. nM). As structure dictates function, we hypothesize that CXCL17-mediated recruitment of immature DCs from the vasculature to the tissues under steady-state conditions plays an important and non-redundant role in mucosal immunosurveillance. Our Specific Aims for this R21 grant are to: Aim 1. Characterize CXCL17-mediated recruitment of DC subtype(s) in vivo in a mouse lung, and recruitment of human DC subtype(s) in vitro using chemotaxis assays. Aim 2. Determine the CXCL17 solution structure and characterize its binding with GAG using NMR spectroscopy; and Aim 3. Determine whether CXCL17 can be converted to a more potent agonist by systematically deleting its N-terminal residues.

描述（申请人提供）：CXCL17是最近发现的一种趋化因子，在肺、胃和小肠等粘膜组织中组成型表达。这些器官通过食物摄入和呼吸持续暴露于多种病原体，因此必须保持高度警惕，以发起快速有效的免疫反应。 CXCL17 可以在此过程中发挥重要作用，因为它选择性地招募未成熟的树突状细胞 (DC)。这些细胞作为免疫哨兵发挥着关键作用，是专业的抗原呈递细胞和 T 细胞功能的关键调节者。目前对于 CXCL17 如何介导其体内功能尚不清楚。趋化因子的特征是它们采用相同的三维结构，具有四个保守的半胱氨酸，形成两个二硫键，并结合糖胺聚糖（GAG）。这两种二硫化物对于受体激活都是必需的，而 GAG 结合对于白细胞的定向迁移至关重要。最值得注意的是，序列分析表明CXCL17仅具有四个保守半胱氨酸中的三个，因此可能不采用典型的趋化因子结构；它也有一个明显不同的带正电残基的分布表明了一种新的 GAG 结合机制。 CXCL17 的另一个不寻常的特征是，它仅在高浓度下才有活性，并且在比大多数趋化因子通常观察到的浓度高 100-1000 倍时显示出最佳活性（?M 与 nM）。由于结构决定功能，我们假设在稳态条件下CXCL17介导的未成熟DC从脉管系统募集到组织在粘膜免疫监视中发挥重要且非冗余的作用。我们此 R21 资助的具体目标是：目标 1. 表征小鼠肺中 CXCL17 介导的 DC 亚型体内招募，以及使用趋化性测定体外人类 DC 亚型招募。目标 2. 确定 CXCL17 溶液结构并使用 NMR 光谱表征其与 GAG 的结合；目标 3. 确定 CXCL17 是否可以通过系统删除其 N 端残基转化为更有效的激动剂。