P13Kdelta Modulation of Neutrophil Trafficking

描述（由申请人提供）：中性粒细胞在炎症中起着重要作用，如果不加控制，可能导致组织损伤。因此，选择性抑制对它们移动到组织中至关重要的途径将具有治疗价值。在这方面，由α、β、γ和δ同种型组成的I类PI 3激酶（PI 3 K）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起关键作用。许多研究集中在它们的功能上，但进展受到缺乏抑制剂的阻碍，这些抑制剂1）无毒，使得它们可以在动物模型中进行研究，2）选择性靶向主要在白细胞中表达的PDK，如δ亚型。利用最近开发的PI 3 K δ的小分子抑制剂IC 87114和p110 δ缺陷小鼠，我们提供了证据，证明这种信号通路是药物开发的有效靶点。口服给药这种化合物的小鼠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的方式类似于在p110 δ无效的动物中观察到的。因此，本申请的目的是确定PI 3 K δ在炎症部位中性粒细胞定位中的生物学作用及其调节精氨酸刺激的内皮的促炎状态的能力。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评估PI 3 K δ在促进炎症肺和关节中中性粒细胞积聚中的作用。在目标2中，我们将确定这种亚型相对于PI 3 K/γ和p38 MAPK信号通路在促进中性粒细胞活化和迁移中的重要性，以响应内源性与细菌衍生的化学引诱物在体外和体内。后者将通过使用活体显微镜直接观察GFP表达细胞的行为来完成。在目标3中，我们将确定Ia类和Ib类PBK是否存在于内皮的功能复合物中，并探索它们参与这种细胞类型募集中性粒细胞的能力的机制。总之，这些研究将确定PI 3 K δ在炎症中性粒细胞募集中的重要性，并提供旨在限制其迁移到组织中的治疗策略的见解。此外，我们的研究结果将确定一个新的作用，一类PBK，炎症内皮细胞的粘附性能的调节。

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.