Neutrophil Chemotaxis in Autoinflammation

描述(申请人提供)：自体炎症综合征包括一组不同类型的遗传性疾病，其特征是反复发作涉及先天免疫系统细胞的无菌性炎症。这些疾病的一个特点是中性粒细胞异常地渗透到组织中，这表明中性粒细胞运输或运动缺陷可能参与了疾病的发病机制。炎症反应中的关键步骤包括白细胞极化和向趋化物质方向迁移。我们工作的长期目标是确定调节中性粒细胞趋化的信号通路，并通过使用斑马鱼作为模型系统在体内检测中性粒细胞的趋化和炎症，了解这些机制在慢性炎症性疾病发病机制中的意义。对调节中性粒细胞趋化的基本机制的了解，应该为自体炎症综合征和其他疾病状态提供治疗靶点，在这些疾病中，炎症是发病机制的核心，包括心脏病、哮喘、关节炎和炎症性肠病。这一建议的优势在于使用我们开发的新型转基因斑马鱼品系，以及应用光遗传学工具来研究体内中性粒细胞的趋化和炎症。指导这项研究的假设是，中性粒细胞的趋化作用由活性氧物种(ROS)、Src家族激酶和酪氨酸磷酸酶信号之间的平衡介导，调节体内炎症的发展和消退。我们提出了以下几点意见来支持这一提议。1.我们最近发现，过氧化氢是一个早期信号，通过氧化介导的Src家族激酶LYN的激活，吸引中性粒细胞进入伤口。2.我们开发了光遗传学工具，可以在体内剖析调节中性粒细胞趋化和双向迁移的分子机制。3.我们首次报道了中性粒细胞从伤口中迁移，这一过程被称为“反向迁移”，它可能介导炎症的局部消退或启动随后的免疫反应。4.我们已经确定了介导中性粒细胞反向迁移的特定信号分子，包括与自身炎症相关的酪氨酸磷酸酶SHP1。我们现在处于独特的位置，可以在以下特定目标上取得快速进展：目的1.阐明Src家族激酶Lyn如何调节斑马鱼中性粒细胞的趋化和炎症。目的2.阐明活性氧(ROS)在中性粒细胞运动和炎症调节中的作用。目的3.以斑马鱼为模型系统，研究体内中性粒细胞在自身炎症中的趋化作用。这项拟议的工作是创新的，因为应用了实时成像和光遗传学工具来解决斑马鱼炎症期间中性粒细胞运动的基本问题。这项工作意义重大，因为它有可能找到控制体内中性粒细胞介导的炎症的新策略，中性粒细胞介导的炎症在许多人类疾病的发病机制中发挥着核心作用，包括心血管疾病、自身免疫和癌症。

DESCRIPTION (provided by applicant): Autoinflammatory syndromes comprise a heterogeneous group of inherited disorders characterized by recurrent episodes of aseptic inflammation involving cells of the innate immune system. A hallmark of these disorders is the abnormal infiltration of neutrophils into tissues, suggesting that defects in neutrophil traffickin or motility may contribute to disease pathogenesis. Critical steps during the inflammatory response include leukocyte polarization and migration in the direction of chemoattractant. The long term goal of our work is to define signaling pathways that regulate neutrophil chemotaxis and to understand the implications of these mechanisms to the pathogenesis of chronic inflammatory disease by using zebrafish as a model system to examine neutrophil chemotaxis and inflammation in vivo. Knowledge of the basic mechanisms that regulate neutrophil chemotaxis should provide therapeutic targets for autoinflammatory syndromes and other disease states in which inflammation is central to pathogenesis, including heart disease, asthma, arthritis and inflammatory bowel disease. The strength of this proposal lies in the use of novel transgenic zebrafish lines that we have developed and the application of optogenetic tools to study neutrophil chemotaxis and inflammation in vivo. The hypothesis that guides this research is that neutrophil chemotaxis, mediated by the balance between reactive oxygen species (ROS), Src family kinases and tyrosine phosphatase signaling modulates the development and resolution of inflammation in vivo. We have made the following observations that support this proposal. 1. We recently discovered that hydrogen peroxide is an early signal that attracts neutrophils to wounds through the oxidation-mediated activation of the Src family kinase, Lyn. 2. We have developed optogenetic tools that allow the dissection of the molecular mechanisms that regulate neutrophil chemotaxis and bidirectional migration in vivo. 3. We were the first to report that neutrophils migrate away from wounds, in a process called "reverse migration" that may mediate local resolution of inflammation or may prime subsequent immune responses. 4. We have identified specific signaling molecules that mediate neutrophil reverse migration, including the tyrosine phosphatase SHP1 that has been associated with autoinflammation. We are now uniquely positioned to make rapid progress with the following Specific Aims: Aim 1. Elucidate how the Src family kinase, Lyn, regulates neutrophil chemotaxis and inflammation in zebrafish. Aim 2. Elucidate the role of reactive oxygen species (ROS) in the regulation of neutrophil motility and inflammation. Aim 3. Use zebrafish as a model system to study neutrophil chemotaxis in autoinflammation in vivo. The proposed work is innovative because of the application of live imaging and optogenetic tools to address fundamental questions about neutrophil motility during inflammation in zebrafish. The work is significant because of the potential to identify new strategies to control neutrophil-mediated inflammation in vivo, which plays a central role in the pathogenesis of many human diseases including cardiovascular disease, autoimmunity and cancer.