PAK1's role in eotaxin-mediated murine eosinophil migration

PAK1 在嗜酸性粒细胞趋化因子介导的小鼠嗜酸性粒细胞迁移中的作用

• 批准号: 8298498
• 负责人: Muithi M Mwanthi
• 金额: $ 1.23万
• 依托单位: INDIANA UNIV-PURDUE UNIV AT INDIANAPOLIS
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-06-01 至 2012-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8298498
• 关键词: Actins; Adrenal Cortex Hormones; Agonist; Albumins; Allergens; Allergic; Asthma; Attenuated; Binding; Biochemical; Blood Cell Count; Blood Cells; CD4 Positive T Lymphocytes; Cell Degranulation; Cells; Centers for Disease Control and Prevention (U.S.); Characteristics; Chemotaxis; Chest; Child; Chronic; Chronic lung disease; Coughing; Cytoskeleton; Data; Development; Disease; Dyspnea; Education; Effector Cell; Eotaxin; Epithelial; F-Actin; Fibroblasts; Genetic; Growth Factor; Helper-Inducer T-Lymphocyte; Heterogeneity; Hospitalization; Human; Immune; Immune system; Immunosuppression; In Vitro; Infiltration; Inflammation; Inflammatory; Influenza A Virus, H1N1 Subtype; Investigation; Knock-out; Knockout Mice; Leukocytes; Low Income Population; Lung; Lung Lavage Fluid; Mediating; Minority; Modeling; Morbidity - disease rate; Mus; Ovum; Pathogenesis; Pathway interactions; Patients; Pharmacotherapy; Phosphotransferases; Physiological; Play; Population; Prevalence; Process; Protein Family; Protein Isoforms; Proteins; Publishing; Pulmonary Heart Disease; Recruitment Activity; Reporting; Research; Respiratory System; Role; Scientist; Serine; Signal Transduction; Signaling Molecule; Specificity; Symptoms; System; T-Lymphocyte Subsets; Target Populations; Testing; Th2 Cells; Therapeutic; Threonine; Tissue Sample; Wheezing; Woman; Work; airway hyperresponsiveness; airway inflammation; base; cdc42 GTP-Binding Protein; cell type; cytokine; depolymerization; eosinophil; eosinophilic inflammation; immortalized cell; in vitro Assay; in vivo; mast cell; migration; mutant; novel; p21 activated kinase; polymerization; prevent; response; rho; scaffold

DESCRIPTION (provided by applicant): For many decades, basic scientists considered asthmatic inflammation as a CD4+ T-helper II (Th2) cell response orchestrated by Th2-synthesized and Th2-secreted cytokines and growth factors. Consequently, many studies have centered around the role aberrant signaling of T helper cell subsets plays in the development of the eosinophilic inflammation typical of asthma. Recent reports, however, suggest roles for other T-cell subsets, the airway microenvironment, and the innate immune system. Although the eosinophil is the most numerous immune effector cell type that propagates chronic asthmatic inflammation, few signaling molecules have successfully been targeted to attenuate its inflammatory functions. The Rho-family of proteins, Cdc42 and Rac implicated in allergen-induced airway inflammation and hyper-reactivity, activate their main effectors serine/threonine p21-activated kinases (PAKs). Through actin-binding effectors, PAK1 modulates the actin cytoskeleton in mast cell degranulation, and additionally we have shown that this isoform is expressed in eosinophils. Eotaxin induced by the allergic sensitization and challenge process powerfully recruits eosinophils to the lungs via CCR3 signaling. We hypothesize that PAK1 modulates eotaxin-mediated eosinophil migration and infiltration and examine its effect using a Pak1 knockout (Pak1-/-) murine system. Previous work we have published and our preliminary data using this model suggest that differential blood cell counts as well as T helper subset function is preserved in the allergen-sensitized and challenged Pak1-/- mouse. Furthermore, eosinophil infiltration in the allergen-sensitized and challenged mouse as well as eotaxin-mediated eosinophil infiltration in vivo and chemotaxis in vitro are impaired by Pak1 genetic deletion. Here we show that PAK1 is activated by the eotaxin: CCR3 signaling in murine eosinophils. Two proposed aims will now focus on delineating the biochemical mechanism by which PAK1 modulates eotaxin-mediated eosinophil migration. In the first aim, we will target and restore PAK1 to thoroughly interrogate the role it plays in eotaxin-mediated migration and F-actin polymerization and depolymerization. Moreover, studies in our second aim will utilize lentiviral expression of PAK1 mutants to dissect out the specific mechanism by which PAK1 exerts this effect. We predict that the results in this project will inform the testing of anti-PAK therapy in preventing the development of eosinophilic inflammation in murine models of asthma.

描述（由申请人提供）：几十年来，基础科学家认为哮喘炎症是由Th 2合成和Th 2分泌的细胞因子和生长因子协调的CD 4 + T辅助II（Th 2）细胞应答。因此，许多研究集中在T辅助细胞亚群的异常信号传导在哮喘典型的嗜酸性粒细胞炎症的发展中所起的作用。然而，最近的报告表明，其他T细胞亚群，气道微环境和先天免疫系统的作用。尽管嗜酸性粒细胞是传播慢性哮喘炎症的最多的免疫效应细胞类型，但很少有信号分子被成功地靶向减弱其炎症功能。Rho家族蛋白Cdc 42和Rac参与过敏原诱导的气道炎症和高反应性，激活其主要效应子丝氨酸/苏氨酸p21激活激酶（PAK）。通过肌动蛋白结合效应子，PAK 1调节肥大细胞脱粒中的肌动蛋白细胞骨架，此外，我们已经表明这种亚型在嗜酸性粒细胞中表达。由过敏性致敏和激发过程诱导的嗜酸性粒细胞趋化因子通过CCR 3信号传导有力地将嗜酸性粒细胞募集到肺。我们假设PAK 1调节嗜酸性粒细胞趋化因子介导的嗜酸性粒细胞迁移和浸润，并使用Pak 1敲除（Pak 1-/-）小鼠系统检查其效果。我们先前发表的工作和我们使用该模型的初步数据表明，在过敏原致敏和激发的Pak 1-/-小鼠中，血细胞分类计数和辅助性T细胞亚群功能得以保留。此外，嗜酸性粒细胞浸润在过敏原致敏和挑战的小鼠，以及嗜酸性粒细胞趋化因子介导的嗜酸性粒细胞浸润在体内和体外趋化性受损的Pak 1基因缺失。在这里，我们表明，PAK 1被激活的嗜酸性粒细胞趋化因子：CCR 3信号在小鼠嗜酸性粒细胞。两个拟议的目标，现在将集中在描绘的生化机制，PAK 1调节嗜酸性粒细胞趋化因子介导的嗜酸性粒细胞迁移。在第一个目标中，我们将靶向和恢复PAK 1，以彻底询问它在嗜酸细胞活化趋化因子介导的迁移和F-肌动蛋白聚合和解聚中所起的作用。此外，我们第二个目标的研究将利用PAK 1突变体的慢病毒表达来剖析PAK 1发挥这种作用的具体机制。我们预测，该项目的结果将为抗PAK治疗在预防哮喘小鼠模型中嗜酸性粒细胞炎症发展方面的测试提供信息。