Understanding Severe Asthma Using an Experimental Model

使用实验模型了解严重哮喘

• 批准号: 9982408
• 负责人: Anuradha Ray
• 金额: $ 49.49万
• 依托单位: UNIVERSITY OF PITTSBURGH AT PITTSBURGH
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-01-07 至 2022-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9982408
• 关键词: Adoptive Transfer; Adrenal Cortex Hormones; Antigens; Asthma; Biological Assay; Bronchoalveolar Lavage; CD4 Positive T Lymphocytes; CXCL10 gene; Cells; Characteristics; Chymase; Complex; DNA; Data; Dendritic Cells; Disease; Dose; Down-Regulation; Experimental Models; Follow-Up Studies; Frequencies; GTP-Binding Proteins; Gene Expression; Genes; Glucocorticoid Receptor; Goals; Human; Immune System Diseases; Inflammation; Inhalation; Interferon Type II; Interleukin-10; Interleukin-12; Lead; Lung; Mediating; Messenger RNA; Molecular; Mucous body substance; Mus; Myosin Heavy Chains; Oral; Outcome Measure; Pathogenesis; Pathway interactions; Patients; Peptide Hydrolases; Phenocopy; Phenotype; Play; Production; Proteins; Publishing; Refractory; Reporter; Reporting; Resolution; Respiratory physiology; Role; SLPI gene; STAT1 gene; Sampling; Signal Transduction; Smooth Muscle Myocytes; Structure of parenchyma of lung; T cell response; T-Lymphocyte; TBK1 gene; Testing; Th1 Cells; Time; Up-Regulation; airway hyperresponsiveness; airway remodeling; asthma exacerbation; asthma model; asthmatic; c-myc Genes; chemokine; chromatin immunoprecipitation; cysteinyl leukotriene receptor; cysteinyl-leukotriene; draining lymph node; effector T cell; inhibitor/antagonist; insight; mRNA Expression; macrophage; mast cell; monocyte; mouse model; novel; peripheral blood; promoter; recruit; response; standard of care; transcription factor; transcriptome sequencing

Severe asthma is a complex heterogeneous disease, which poorly responds to corticosteroids (CS), the current standard of care for asthma. In a previous study, we reported that bronchoalveolar lavage (BAL) cells in >50% of subjects with severe asthma (SA) secrete high levels of IFN-γ from CD4+ T cells despite treatment of the subjects with high doses of inhaled CS, often combined with oral CS. In a recent follow-up study to understand the molecular mechanisms that promote a persistent Th1high phenotype in SA, we have shown an essential role for the transcription factor IRF5 in promoting IL-12 production from lung dendritic cells (DCs) and macrophages (Mφs) to elicit high levels of IFN-γ production from T cells. In another study published recently, we show that SA subjects with a Th1high profile harbor higher levels of expression of the Th1-recruiting chemokine CXCL10 in their airways compared to mild asthma subjects, strongly associated with IFN-γ expression, frequency of oral CS use, and expression of mast cell-specific proteases. Chromatin immunoprecipitation (ChIP) assay used to determine high CXCL10 levels in SA revealed recruitment of both STAT1 to and GR to the CXCL10 promoter with no accompanying suppression of CXCL10 mRNA expression. While CS were unable to suppress IFN-γ-induced CXCL10 mRNA and protein levels in monocytes, IL-10 completely inhibited CXCL10 gene expression in the context of IFN-γ and CS, an effect not realized in many severe asthmatics. In new data generated using RNA-seq approaches, we show downregulation of the negative regulator of TGF-β1-mediated signaling, Smad7, and upregulation of c-Myc, in lungs of mice subjected to the SA model, which may impact mast cells and airway remodeling. Indeed in our recent report we have shown a strong correlation between CXCL10 mRNA and mast cell signatures in humans and mice. Mast cells produce cysteinyl leukotrienes (CysLTs), and our RNA-seq data show that IFN-γ selectively upregulates expression of the CysLT receptor, CySLTR2, in the lung. Collectively, these studies lead us to hypothesize that the IRF-5-IFN-γ-CXCL10 axis in the context of CS induces a feed-forward loop promoting a Th1high phenotype that impacts lung function and airway remodeling involving mast cells. Although refractory to CS, the Th1high state is sensitive to IL-10. To test this hypothesis we will: Aim 1. Establish IRF5 in lung APCs as a sustainer of Th1 (IFN-γ) effector function and identify IRF5 SNPs in humans. Aim 2. Determine the role of specific IFN-γ-regulated molecules and mast cells in disease pathogenesis in the SA model. Aim 3. Investigate defective IL-10 production in T cells in humans with SA and study inhibition by IL-10 of CS- refractory CXCL10 gene expression induced by IFN-γ.

严重哮喘是一种复杂的异质性疾病，对皮质类固醇（CS）反应较差