MOLECULAR AND FORCE DYNAMICS IN NEUTROPHIL RECRUITMENT

中性粒细胞募集的分子和力动力学

• 批准号: 6647708
• 负责人: Scott Irwin Simon
• 金额: $ 25.62万
• 依托单位: UNIVERSITY OF CALIFORNIA AT DAVIS
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-07-01 至 2004-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6647708
• 关键词: biological signal transduction; cell adhesion; cell migration; flow cytometry; human subject; integrins; leukocyte activation /transformation; neutrophil; selectins; tissue /cell culture; vascular endothelium

DESCRIPTION (verbatim from the proposal): Leukocytes interacting with the endothelium at sites of acute inflammation pass through a multistep cascade of events initiated by leukocyte margination to the vessel wall and proceeding to transmigration into the tissue. While members of the selectin family mediate the tethering and rolling of PMNs on the endothelium, cell arrest is dependent on members of the beta2-integrin family. This process is critical for initiation of the host immune response to bacterial and fungal pathogens, and is a common target for therapeutic intervention in inflammation. Central to the transition from cell tethering to stable adhesion and transmigration is the activation of leukocyte integrins to bind to intercellular adhesion molecule-1 (ICAM-1) upregulated on inflamed endothelium. The formation of integrin bonds in sufficient number provides the cell adhesion strength that balances the drag forces of flowing blood. This multistep process of emigration also applies to neutrophil-neutrophil aggregation. We have established that homotypic aggregation also requires L-selectin tethering and beta2-integrin binding. Current published data suggest that selectin receptors can also function as signal transduction molecules in facilitating leukocyte activation. In this application we will test the hypothesis that tethering and signaling through selectins serves to increase the efficiency of margination, firm adhesion, and transmigration of neutrophils. Two specific aims are proposed. 1) To determine the biophysical mechanisms underlying the transition from selectin tethering to integrin-dependent firm adhesion under defined shear. 2) To examine how tethering through L-selectin signals PMN activation and integrin-dependent adhesion. Our experimental strategy is to study neutrophils isolated from human blood and maintained in a pristine state. Only in this manner can we attempt to apply viscometry and flow cytometric techniques to measure the rapid molecular recognition and signaling events under defined hydrodynamic shear fields with millisecond resolution. Neutrophil-neutrophil, and neutrophil-endothelial adhesion will be measured in native cells and stable cell lines transfected to express specific leukocyte and vascular adhesion molecules. The overall objective of these studies is to reveal the dual functions of the selectins in tethering and signaling adhesion functions in neutrophils.

描述（提案逐字逐句）：白细胞在急性炎症部位与内皮相互作用，经历由白细胞边缘化到血管壁引发的多步级联事件，然后迁移到组织中。虽然选择素家族的成员介导 PMN 在内皮上的束缚和滚动，但细胞停滞依赖于 β2-整合素家族的成员。这一过程对于启动宿主对细菌和真菌病原体的免疫反应至关重要，并且是炎症治疗干预的常见目标。从细胞束缚到稳定粘附和迁移的转变的核心是白细胞整合素的激活，以与发炎内皮细胞上调的细胞间粘附分子-1 (ICAM-1) 结合。足够数量的整合素键的形成提供了平衡流动血液的阻力的细胞粘附强度。这种迁移的多步骤过程也适用于中性粒细胞-中性粒细胞聚集。我们已经确定同型聚集也需要 L-选择素束缚和 β2-整联蛋白结合。目前发表的数据表明，选择素受体还可以充当促进白细胞激活的信号转导分子。在此应用中，我们将测试以下假设：通过选择素的束缚和信号传导有助于提高中性粒细胞的边缘化、牢固粘附和迁移的效率。提出了两个具体目标。 1）确定在确定的剪切力下从选择素束缚转变为整合素依赖性牢固粘附的生物物理机制。 2) 检查通过 L-选择素的束缚如何发出 PMN 激活和整合素依赖性粘附信号。我们的实验策略是研究从人类血液中分离并保持原始状态的中性粒细胞。只有这样，我们才能尝试应用粘度测定和流式细胞术技术来测量在定义的流体动力剪切场下以毫秒分辨率的快速分子识别和信号事件。将在天然细胞和转染表达特定白细胞和血管粘附分子的稳定细胞系中测量中性粒细胞-中性粒细胞和中性粒细胞-内皮粘附。这些研究的总体目标是揭示选择素在中性粒细胞中束缚和信号粘附功能中的双重功能。