P13Kdelta Modulation of Neutrophil Trafficking

P13Kdelta 中性粒细胞运输的调节

• 批准号: 7098726
• 负责人: Thomas G Diacovo
• 金额: $ 35.37万
• 依托单位: COLUMBIA UNIVERSITY HEALTH SCIENCES
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-08-01 至 2009-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7098726
• 关键词: arthritis; biological signal transduction; bone marrow transplantation; cell adhesion; cell adhesion molecules; cell migration; chemoattractants; chemokine; chemotaxis; clinical research; disease /disorder model; enzyme activity; genetically modified animals; human subject; immunoprecipitation; inflammation; intravital microscopy; isozymes; kinase inhibitor; knee; laboratory mouse; leukocyte activation /transformation; lung injury; mitogen activated protein kinase; neutrophil; phosphatidylinositol 3 kinase; vascular endothelium

DESCRIPTION (provided by applicant): Neutrophils play a prominent role in inflammatory conditions, which if uncontrolled, can result in tissue injury. Thus, selective inhibition of a pathway critical for their movement into tissues would be of therapeutic value. In this regard, class I PI3 kinases (PBKs), consisting of a, P, gamma, and delta isoforms, make attractive targets as they play a pivotal role in chemokine-directional migration of these cells. Much research has concentrated on their functions, but progress has been hampered by the lack of inhibitors that 1) are nontoxic so that they may be studied in animal models, and 2) selectively target PDKs that are primarily expressed in leukocytes such as the delta isoform. Utilizing the recently developed small molecule inhibitor of PI3Kdelta, IC87114, and mice deficient in p110delta we provide evidence that this signaling pathway is a valid target for drug development. Oral administration of this compound to mice reduced chemokine-mediated migration and interestingly, adhesive interactions of neutrophils with the vessel wall in a manner analogous to that observed in p110delta null animals. Thus, the purpose of this application is to define the biological role of PI3Kdelta in neutrophil localization at sites of inflammation and its ability to modulate the proinflammatory state of cytokine-stimulated endothelium. Our studies will be directed at three specific aims. In Aim 1, we will evaluate the role of PI3Kdelta in promoting neutrophil accumulation in inflamed lung and joints using murine models that replicate disease states in man. In Aim 2, we will determine the importance of this isoform relative to PI3K/gamma and the p38MAPK signaling pathways in promoting neutrophil activation and migration in response to endogenous vs. bacteria-derived chemoattractants in vitro and in vivo. The latter will be accomplished by direct visualization of the behavior of GFP-expressing cells using intravital microscopy. In Aim 3, we will determine whether class la and Ib PBKs exist in functional complexes in endothelium and explore the mechanism(s) by which they participate in the ability of this cell type to recruit neutrophils. Together, these studies will determine the importance of PI3Kdelta in neutrophil recruitment in inflammation as well as provide insight into therapeutic strategies designed to limit their migration into tissues. Moreover, our results will define a new role for class I PBKs, regulation of the adhesive properties of inflamed endothelium.

描述（由申请人提供）：中性粒细胞在炎症中发挥着重要作用，如果不加以控制，可能会导致组织损伤。因此，选择性抑制对于它们进入组织至关重要的途径将具有治疗价值。在这方面，由 a、P、gamma 和 delta 同工型组成的 I 类 PI3 激酶 (PBK) 成为有吸引力的靶标，因为它们在这些细胞的趋化因子定向迁移中发挥着关键作用。许多研究都集中在它们的功能上，但由于缺乏抑制剂，进展受到阻碍：1) 无毒，因此可以在动物模型中研究它们，2) 选择性靶向主要在白细胞中表达的 PDK，例如 δ 亚型。利用最近开发的 PI3Kdelta 小分子抑制剂 IC87114 和缺乏 p110delta 的小鼠，我们提供了证据表明该信号通路是药物开发的有效靶点。给小鼠口服这种化合物可以减少趋化因子介导的迁移，有趣的是，中性粒细胞与血管壁的粘附相互作用以类似于在 p110delta 缺失动物中观察到的方式减少。因此，本申请的目的是确定 PI3Kdelta 在炎症部位中性粒细胞定位中的生物学作用及其调节细胞因子刺激的内皮促炎状态的能力。我们的研究将针对三个具体目标。在目标 1 中，我们将使用复制人类疾病状态的小鼠模型来评估 PI3Kdelta 在促进发炎肺部和关节中中性粒细胞积累中的作用。在目标 2 中，我们将确定该亚型相对于 PI3K/gamma 和 p38MAPK 信号通路在促进中性粒细胞响应内源性与细菌来源的化学引诱剂的体外和体内活化和迁移方面的重要性。后者将通过使用活体显微镜直接观察表达 GFP 的细胞的行为来完成。在目标 3 中，我们将确定 la 类和 Ib 类 PBK 是否存在于内皮功能复合物中，并探索它们参与该细胞类型募集中性粒细胞能力的机制。总之，这些研究将确定 PI3Kdelta 在炎症中中性粒细胞募集中的重要性，并深入了解旨在限制其迁移到组织中的治疗策略。此外，我们的结果将定义 I 类 PBK 的新作用，即调节发炎内皮的粘附特性。