Glucocorticoid receptor translational isoforms in asthma

哮喘中的糖皮质激素受体翻译亚型

基本信息

批准号：
8448648
负责人：
NICK LU
金额：
$ 35.58万
依托单位：
NORTHWESTERN UNIVERSITY AT CHICAGO
依托单位国家：
美国
项目类别：
财政年份：
2009
资助国家：
美国
起止时间：
2009-04-01 至 2014-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8448648
关键词：
Adrenal Glands Adverse effects Animals Anti-Inflammatory Agents Anti-inflammatory Antigens Apoptosis Asthma Biological Models Bone Marrow CD4 Positive T Lymphocytes Cell Line Cell model Cells Data Dendritic Cells Development Disease Drug Targeting Drug or chemical Tissue Distribution Eukaryotic Initiation Factors Gene Expression Gene Expression Regulation Glucocorticoid Receptor Glucocorticoid-induced apoptosis Glucocorticoids Goals Helper-Inducer T-Lymphocyte Immune Immunity Immunosuppressive Agents Individual Inflammation Inflammatory Inflammatory Response Informatics Ligands Lipopolysaccharides Lung Mediastinal lymph node group Mediating Messenger RNA Metabolic syndrome Modeling Mus Odds Ratio Osteoblasts Osteoporosis Pattern Pharmaceutical Preparations Pituitary Gland Play Production Protein Isoforms Regulation Regulatory T-Lymphocyte Resistance Role Scanning Sentinel Staging Stimulus T-Lymphocyte T-Lymphocyte Subsets Testing Toll-like receptors Translations Work abstracting airborne allergen base cell type cytokine design improved killings pathogen respiratory risk benefit ratio selective expression stable cell line therapy development translation factor uptake

项目摘要

Abstract: Glucocorticoids are indispensable in the treatment of asthma and other inflammatory diseases although side effects such as hypothalamo-pituitary-adrenal suppression, metabolic syndrome, and osteoporosis limit their use. Our goal is to understand the mechanisms by which the glucocorticoid receptor (GR) mediates cell-specific functions, as this information may be useful in the development of treatments for asthma with improved efficacy/risk ratios. We have recently discovered that the GR has eight distinct translational isoforms expressed variably in a wide range of cell types. These GR isoforms have profoundly different effects on gene expression. We hypothesize that selective GR translational isoforms mediate distinct sensitivities to glucocorticoid-induced apoptosis and regulate cell-specific inflammatory responses in T cell and dendritic cell subsets that are crucial in asthma. We propose that inflammatory stimuli selectively regulate GR isoforms via translational mechanisms. To test these hypotheses, we will examine primary T cells and dendritic cells obtained from a murine asthma model, cell lines expressing individual GR isoforms, and bone marrow-derived dendritic cells. Studies in Aim 1 will determine in a murine asthma model the identity and function of GR translational isoforms in helper T cells that are sensitive and regulatory T cells (Tregs) that are resistant to glucocorticoid-induced apoptosis. Our preliminary data indicate that helper T cells express predominantly the proapoptotic GR-A isoform whereas Tregs have predominantly the GR-D isoforms that are incapable of inducing apoptosis in osteoblast and T cell model systems. We will determine the role of selective GR isoforms in T cell subset-specific functions and glucocorticoid sensitivities. Studies in Aim 2 will determine the identity and function of GR translational isoforms in immature and mature dendritic cells that also have distinct sensitivities to glucocorticoid-induced apoptosis. Our preliminary data indicate that immature dendritic cells switch from the GR-D isoforms to expressing the GR-A isoform after maturation. The role of GR isoforms in distinct glucocorticoid sensitivities of immature (insensitive) and mature (sensitive) dendritic cells and in maturational-stage specific functions will be determined. Studies in Aim 3 will determine the role of translation machinery in regulating the expression of selective GR isoforms. Our previous studies indicate that the GR translational isoforms are produced from a single species of mRNA via ribosomal leaky scanning and ribosomal shunting. Based on our preliminary results, we will focus on the role of eukaryotic initiation factors in selective expression of GR isoforms. These studies will improve our understanding of the cell-specific actions of GR translational isoforms in asthma. Selective GR isoforms are anticipated to mediate cell-specific sensitivities to glucocorticoids and regulate cell- specific functions. In addition, these studies may provide a basis for the development of anti- inflammatory drugs targeting or altering the expression of selective GR isoforms.

摘要：糖皮质激素在哮喘等炎症性疾病的治疗中不可或缺。尽管副作用如下丘脑-垂体-肾上腺抑制、代谢综合征和骨质疏松症限制了它们的使用。我们的目标是了解糖皮质激素受体的机制（GR）介导细胞特异性功能，因为该信息可能有助于开发治疗方法哮喘的疗效/风险比得到改善。我们最近发现 GR 有八个不同的翻译异构体在多种细胞类型中表达不同。这些 GR 同工型具有深远的影响对基因表达的不同影响。我们假设选择性 GR 翻译异构体介导对糖皮质激素诱导的细胞凋亡具有不同的敏感性并调节细胞特异性炎症 T 细胞和树突状细胞亚群的反应对于哮喘至关重要。我们建议炎症刺激通过翻译机制选择性地调节 GR 同工型。为了检验这些假设，我们将检查从小鼠哮喘模型获得的原代 T 细胞和树突状细胞，细胞系表达个体 GR 亚型和骨髓来源的树突状细胞。目标 1 的研究将在小鼠中确定哮喘模型辅助性 T 细胞中 GR 翻译亚型的身份和功能对糖皮质激素诱导的细胞凋亡具有抵抗力的调节性 T 细胞 (Treg)。我们的初步数据表明辅助性 T 细胞主要表达促凋亡 GR-A 亚型，而 Tregs 主要表达 GR-D 亚型无法在成骨细胞和 T 细胞模型系统中诱导细胞凋亡。我们将确定选择性 GR 亚型在 T 细胞亚群特异性功能和糖皮质激素敏感性中的作用。目标 2 的研究将确定未成熟和成熟中 GR 翻译亚型的身份和功能树突状细胞对糖皮质激素诱导的细胞凋亡也具有明显的敏感性。我们的初步数据表明未成熟的树突状细胞从 GR-D 亚型转变为表达 GR-A 亚型成熟。 GR亚型在未成熟（不敏感）和成熟的不同糖皮质激素敏感性中的作用（敏感）树突状细胞和成熟阶段的特定功能将被确定。目标 3 的研究将确定翻译机制在调节选择性 GR 亚型表达中的作用。我们之前的研究表明，GR 翻译亚型是由单一种类的 mRNA 通过核糖体产生的漏扫描和核糖体分流。根据我们的初步结果，我们将重点关注 GR亚型选择性表达的真核起始因子。这些研究将改善我们的了解 GR 翻译亚型在哮喘中的细胞特异性作用。选择性GR 预计异构体可介导细胞对糖皮质激素的特异性敏感性并调节细胞具体功能。此外，这些研究可能为抗病毒药物的开发提供基础。靶向或改变选择性 GR 亚型表达的炎症药物。