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）：中性粒细胞在炎症条件下起着重要作用，如果不受控制，可能会导致组织损伤。因此，选择性抑制对其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）在这些细胞的趋化因子方向迁移中起着关键作用，从而使它们成为有吸引力的靶标。许多研究集中在其功能上，但是由于缺乏抑制剂1）无毒的抑制剂阻碍了进步，因此可以在动物模型中研究它们，而2）有选择地靶向主要在白细胞中主要表达的PDK，例如Delta同工型。利用最近开发的PI3KDELTA，IC87114的小分子抑制剂和缺乏p110delta的小鼠，我们提供了证据，表明该信号传导途径是药物开发的有效目标。对小鼠的口服给药减少了趋化因子介导的迁移，有趣的是，中性粒细胞与血管壁的粘合性相互作用类似于在p110delta null动物中观察到的。因此，该应用的目的是定义PI3KDELTA在炎症部位的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细胞促炎状态的能力。我们的研究将针对三个具体目标。在AIM 1中，我们将使用复制人类中疾病状态的鼠模型来评估PI3KDELTA在发炎肺和关节中促进中性粒细胞积累的作用。在AIM 2中，我们将确定该同工型相对于PI3K/GAMMA的重要性以及p38MAPK信号传导途径在促进中性粒细胞激活和迁移中，响应内源性与细菌衍生的介摄取物在体外和体内迁移。后者将通过使用插入式显微镜直接可视化表达GFP细胞的行为来实现。在AIM 3中，我们将确定LA和IB类PBK是否存在于内皮的功能复合物中，并探索它们参与该细胞类型募集嗜中性粒细胞的能力的机制。总之，这些研究将确定PI3KDELTA在炎症中募集中性粒细胞中的重要性，并提供对旨在限制其迁移到组织的治疗策略的见解。此外，我们的结果将定义I类PBK的新作用，调节发炎的内皮的粘合剂特性。