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（由申请人提供）：最近发现的趋化因子CXCL17在肺，胃和小肠等粘膜组织中的组成症表达。这些器官通过食物摄入和呼吸不断暴露于多种病原体，因此必须高度戒备才能实现快速有效的免疫反应。 CXCL17可以在此过程中起重要作用，因为它有选择地募集未成熟的树突状细胞（DC）。这些细胞作为免疫哨兵起着关键作用，是专业的抗原细胞，也是T细胞功能的关键调节剂。目前，对于CXCL17如何介导其体内功能尚无任何了解。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，它们形成两个二硫键，并结合糖胺聚糖（GAGS）。两种二硫化物对于受体的激活都是必不可少的，而插科打结合对于白细胞的定向迁移至关重要。最引人注目的是，序列分析表明，CXCL17只有四个保守的半胱氨酸中的三个，因此不得采用典型的趋化因子结构。它也有明显的不同带正电残基的分布，表明一种新型的插科打结合机制。 CXCL17的另一个不寻常特征是它仅在高浓度下活跃，并且在100-1000倍的浓度下显示出比通常观察到的大多数趋化因子（？M vs. NM）的最佳活性。正如结构决定功能的那样，我们假设CXCL17介导的未成熟DC从脉管系统到组织在稳态条件下的募集起着重要且不冗余的作用在粘膜免疫监测中。我们对R21赠款的具体目的是：AIM 1。表征CXCL17介导的小鼠肺体内DC亚型的募集，以及使用化学X。在体外募集人DC亚型。 AIM 2。确定CXCL17溶液结构，并使用NMR光谱表征其与GAG的结合； AIM3。通过系统地删除其N末端残基，确定CXCL17是否可以转换为更有效的激动剂。