LEUCOCYTE ADHESION IN ALLERGIC INFLAMMATION

循环中嗜酸性粒细胞粘附于血管内皮并聚集到炎症组织的血管外部位是过敏性炎症的标志。 最近的研究已经确定了一个重要的作用，粘附分子和其他介质的隔离嗜酸性粒细胞的炎症部位。 在这种竞争性更新中，我们首先假设血管细胞粘附分子（VCAM-1）是一种多功能细胞粘附分子，通过与α 4整合素的不同活化状态相互作用，支持嗜酸性粒细胞的初始滚动、活化依赖性稳定粘附和趋化因子介导的迁移。 使用VCAM-1缺陷杂合子小鼠，我们将确定VCAM-1对嗜酸性粒细胞募集到皮肤和腹膜中过敏性炎症部位的组织特异性贡献。 我们的研究已经确定，CD 44可能作为一种新的滚动受体的人嗜酸性粒细胞。此外，C3 a似乎充当嗜酸性粒细胞活性化学引诱物以介导滚动细胞的稳定粘附。 因此，我们将研究CD 44和C3 a在嗜酸性粒细胞介导的过敏性炎症中的功能。 由于基质金属蛋白酶（MMPs）在白细胞在血管外空间的迁移中发挥重要作用，我们将研究嗜酸性粒细胞表达的MMP-9以及可诱导的嗜酸性粒细胞特异性MMP（称为MMP-E）在介导嗜酸性粒细胞中的重要性体内趋化性作为第二个具体目标的一部分。此外，将产生针对MMP-E的单克隆抗体，以更好地理解在嗜酸性粒细胞募集和过敏性炎症的背景下MMP-E的生物化学和功能调节。 由于暴露于细胞因子如IL-5导致显著的嗜酸性粒细胞增多，在第三个具体目标中，将研究IL-5/变应原诱导的骨髓中造血祖细胞/干细胞（HPSC）和嗜酸性粒细胞定向祖细胞的动员机制。 我们还将研究IL-5如何调节HPSC从骨髓微环境（基质细胞和内皮细胞）到过敏性炎症远端部位（流动条件下的肺内皮细胞）的运输/迁移。 使用活体显微镜沿着体外分子和细胞工具的体内技术，拟议的研究旨在更好地了解炎症血管和组织中介导嗜酸性粒细胞相互作用的分子机制，并为开发治疗过敏性炎症的新治疗策略提供基础。

Adherence of circulating eosinophil to vascular endothelium and their recruitment to extravascular sites in inflamed tissues is the hallmark of allergic inflammation. Recent studies have identified an important role for adhesion molecules and other mediators in the sequestration of eosinophils to sites of inflammation. In this competing renewal we first postulate that vascular cell adhesion molecule (VCAM-1) is a multifunctional cell adhesion molecule that supports initial rolling, activation dependent stable adhesion and chemokine mediated transmigration of eosinophils by interacting with different activation states of alpha4 integrins. Using VCAM-1 deficient heterozygous mice we will determine the tissue specific contribution of VCAM-1 to eosinophil recruitment to sites of allergic inflammation in the skin and peritoneum. Our studies have identified that CD44 may function as a novel rolling receptor for human eosinophils. Furthermore, C3a appears to function as a eosinophil active chemoattractant to mediate stable adhesion of rolling cells. We will therefore, examine the function of CD44 and C3a in eosinophil mediated allergic inflammation. Since matrix matalloproteinases (MMPs) play an important role in the migration of leukocytes within the extravascular space, we will examine the importance of eosinophil expressed MMP-9 as well as an inducible eosinophil-specific MMP, designated as MMP-E, in mediating eosinophil chemotaxis in vivo as part of the second specific aim. In addition monoclonal antibodies against MMP-E will be generated with a view to better understand the biochemical and functional regulation of MMP-E in the context of eosinophil recruitment and allergic inflammation. Since exposure to cytokines such as IL-5 leads to significant eosinophilia, in the third specific aim, the mechanisms of IL-5/allergen-induced mobilization of hematopoietic progenitor/stem cell (HPSC) and eosinophil committed progenitors in the bone marrow will be investigated. We will also investigate how IL-5 modulates the trafficking/migration of HPSC from the bone marrow microenvironment (stromal and endothelial cells) to distal sites of allergic inflammation (lung endothelial cells under conditions of flow. Using in vivo techniques of intravital microscopy along with in vitro molecular and cellular tools, the proposed studies are intended to give a better understanding of the molecular mechanisms mediating eosinophil interactions in inflamed blood vessels and tissues and to provide a basis for developing novel therapeutic strategies for treatment of allergic inflammation.