ROLE OF BETA-2 INTEGRINS IN LEUKOCYTE ADHESION AND SIGNALING

白细胞对炎症部位的吸引是必不可少的。 动态平衡反应。髓系细胞的不适当吸引和激活 然而，白细胞是一种导致多种疾病的机制。 以明显的炎症为特征。精准调控 招聘过程是必要的，以适当地回应和 防止过度的组织损伤。许多细胞和分子 对此响应中涉及的事件进行了描述。Beta2 整合素是中性粒细胞表面的一类黏附蛋白 巨噬细胞在支持正常炎症中起关键作用 回应。例如，患有这些遗传性缺陷的患者 蛋白质遭受反复的增强生命的感染，并且有很差的 伤口愈合。相反，阻断黏附功能的抗体 β2整合素对某些动物模型组织损伤的改善作用 发炎。Beta2整合素是由常见的Beta组成的二聚体 链和三个阿尔法链中的一个。尽管它们的主要结构 都是已知的，许多功能反应已经被表征，它是 尚不清楚每个异源二聚体是否对 粘附力和信号。 我们建议用HL60细胞建立永久细胞系，HL60细胞是一种早幼粒细胞 在体外可分化为PMN-或巨噬细胞-的白血病株 就像细胞一样。每一行将缺少一个亚单位(即 贝塔，或阿尔法中的一个)通过靶向基因破坏 同源重组。我们将创建纯合子线条并使用它们 确定每个单独的杂二聚体对粘附性的贡献 以候选其他细胞和细胞外的反受体 矩阵。我们将使用相同的细胞来评估每个整合素的作用 在配体诱导的反应中，包括细胞内钙的变化 浓度、氧化剂猝发、脂质介体的合成和基因 表情。拟议的研究将剖析Beta2的功能。 分子水平的整合素，并将为 研究白细胞功能、整合素和炎症。

The attraction of leukocytes to a site of inflammation is an essential homeostatic response. Inappropriate attraction and activation of myeloid leukocytes, however, is a mechanism underlying a variety of diseases characterized by marked inflammation. Precise regulation of the recruitment process is necessary both to respond appropriately and to prevent excessive tissue damage. Many of the cellular and molecular events involved in this response have been described. The Beta2 integrins are a family of adhesion proteins on the surface of PMNs and macrophages that are crucial in supporting a normal inflammatory response. For example, patients with an inherited deficiency of these proteins suffer recurrent life-strengthening infections and have poor wound healing. Conversely, antibodies that block the adhesive function of Beta2 integrins ameliorate the tissue damage in some animal models of inflammation. The Beta2 integrins are dimers comprised of a common Beta chain and one of three alpha chains. Although their primary structures are known and many functional responses have been characterized, it is not clear whether each of the heterodimers makes unique contributions to adhesion and signaling. We propose to make permanent cell lines from HL60 cells, a promyelocytic leukemia line that can be differentiated in vitro to PMN- or macrophage- like cells. Each line will have a deficiency of one subunit (i.e. the Beta, or one of the alpha's) created by targeted gene disruption through homologous recombination. We will create homozygous lines and use them to determine the contribution of each individual heterodimer to adhesion to candidate counter-receptors on other cells and in extracellular matrix. We will use the same cells to assess the role of each integrin in ligand-induced responses including changes in intra cellular calcium concentration, the oxidant burst, synthesis of lipid mediators, and gene expression. The proposed studies will dissect the functions of the Beta2 integrins at the molecular level, and will provide permanent reagents for studies of leukocyte function, integrins, and inflammation.