Role of Spi-C in eosinophil development and functional responses

描述(申请人提供)：嗜酸性粒细胞增多症发生在各种临床疾病中，包括寄生虫感染、高嗜酸性粒细胞综合征、癌症和特应性疾病。嗜酸性粒细胞来源于表达转录因子GATA-1和白细胞介素5受体α(IL-5RA)的谱系定向造血祖细胞。尽管GATA-1在嗜酸性粒细胞发育中的意义已被充分证实，但指导嗜酸性粒细胞定向祖细胞分化为成熟嗜酸性粒细胞的调控途径尚不清楚，特别是与其他造血祖细胞相比。候选人富尔克森博士的长期目标是确定新的治疗靶点，以阻止嗜酸性粒细胞的产生和招募，用于治疗嗜酸性哮喘和其他炎症性疾病患者。富尔克森博士致力于学术医学的事业，并致力于成为一名独立的研究调查员。该提案中概述的培训计划将为Fulkerson博士提供一个建立科学定位的机会，并促进Fulkerson博士在提案第三年提交R01补助金后成熟为一名独立的内科科学家。这项建议的目的是描述转录因子SPI-C在嗜酸性粒细胞成熟过程中的调节活性。SPI-C在成熟嗜酸性粒细胞或嗜酸性粒细胞分化中的作用完全未知。这些研究有望通过调节IL-5RA的表达和嗜酸性粒细胞颗粒蛋白的表达，对嗜酸性粒细胞分化、存活和效应功能的重要途径有一个详细的了解。明确嗜酸性粒细胞功能和IL-5反应性的分子调节机制无疑将为临床应用提供关键信息，特别是考虑到目前正在积极开发的IL-5RA和IL-5导向疗法。这一建议的中心假设是，转录因子SPI-C与转录因子PU.1和GATA-1协调，通过调节对嗜酸性粒细胞生存、增殖和效应功能至关重要的基因的表达来调节嗜酸性粒细胞的分化。我们将通过三个具体目标来检验这一假设。首先，我们将使用Fulkerson博士开发的一种新的体外培养系统来确定SPI-C在嗜酸性粒细胞成熟中的作用，该系统可导致表型成熟的嗜酸性粒细胞。其次，我们将表征SPI-C和PU.1对IL-5RA的调节。最后，我们将确定SPI-C和PU.1在调节嗜酸性粒细胞颗粒蛋白表达中的作用。总之，拟议的研究将阐明SPI-C在嗜酸性粒细胞分化中的作用。具体地说，这些研究将描述SPI-C和PU.1对颗粒蛋白表达和IL-5反应性的调节。由于颗粒蛋白的释放是嗜酸性粒细胞的重要效应功能，而IL-5信号在与疾病相关的嗜酸性粒细胞增多症中起关键作用，进一步明确它们的调控可能会导致嗜酸性粒细胞相关疾病的新的治疗靶点。 项目简介嗜酸性粒细胞在组织中的聚集和激活发生在各种临床疾病中，包括寄生虫感染、高嗜酸性粒细胞综合征、癌症和特应性疾病，并导致细胞毒性颗粒蛋白的释放，激活和损害邻近细胞，导致组织损伤、器官功能障碍和患者发病率。预计拟议的研究将提供对嗜酸性粒细胞分化、生存和效应功能，特别是颗粒蛋白产生的重要途径的详细了解。这项提案将为临床应用提供关键信息，特别是考虑到目前正在积极开发的嗜酸性粒细胞靶向疗法。

DESCRIPTION (provided by applicant): Eosinophilia occurs in a variety of clinical disorders including parasitic infections, hypereosinophilic syndrome, cancer, and atopic diseases. Eosinophils are derived from lineage-committed hematopoietic progenitor cells expressing the transcription factor GATA-1 and interleukin-5 receptor alpha (IL-5Ra). Although the significance of GATA-1 in eosinophil development is well established, the regulatory pathways that direct the differentiation of the eosinophil lineage-committed progenitor to mature eosinophils are not well understood, especially when compared with other hematopoietic lineages. The long term goals of the candidate, Dr. Fulkerson, are to identify novel therapeutic targets to block eosinophil production and recruitment for the treatment of patients with eosinophilic asthma and other inflammatory disorders. Dr. Fulkerson is dedicated to a career in academic medicine and to becoming an independent research investigator. The training plan outlined in this proposal will provide Dr. Fulkerson an opportunity to establish a scientific niche and facilitate the maturation of Dr. Fulkerson into an independent physician scientist with submission of a R01 grant in year three of the proposal. The objective of this proposal is to delineate the regulatory activity of the transcription factor Spi-C in eosinophil maturation. The role of Spi-C in mature eosinophils or eosinophil differentiation is completely unknown. The proposed studies are expected to provide a detailed understanding of the pathways important for eosinophil differentiation, survival and effector function via regulation of IL-5Ra expression and expression of eosinophil granule proteins. Defining the molecular regulators of eosinophil function and IL-5 responsiveness will undoubtedly provide key information with clinical applications, especially given the IL-5Ra- and IL-5-directed therapies that are currently under avid development. The central hypothesis of this proposal is that the transcription factor Spi-C coordinates with the transcription factors PU.1 and GATA-1 to regulate eosinophil differentiation via regulation of expression of genes important for eosinophil survival, proliferation and effector function. We will test this hypothesis with three specific aims. First, we will identify the role of Spi-C in eosinophil maturation using a novel in vitro culture system developed by Dr. Fulkerson that results in phenotypically mature eosinophils. Second, we will characterize the regulation of IL-5Ra by Spi-C and PU.1. Finally, we will determine the role of Spi-C and PU.1 in regulating expression of eosinophil granule proteins. Together, the proposed studies will elucidate the role of Spi-C in eosinophil differentiation. Specifically, the studies will delineate the regulation of granule protein expression and IL-5 responsiveness by Spi-C and PU.1. As release of granule proteins is an important effector function of eosinophils and IL-5 signaling is critical to eosinophilia associated with disease, further defining their regulation could lead to new therapeutic targets in eosinophil-associated disorders. Project Narrative Eosinophil accumulation and activation in tissues occurs in a variety of clinical disorders including parasitic infections, hypereosinophilic syndrome, cancer, and atopic diseases and results in the release of cytotoxic granule proteins that activate and damage neighboring cells leading to tissue damage, organ dysfunction and patient morbidity. The proposed studies are expected to provide a detailed understanding of the pathways important for eosinophil differentiation, survival and effector function, particularly production of granule proteins. This proposal will provide key information with clinical applications, especially given the eosinophil- targeted therapies that are currently under avid development.