Sprouty-2 Regulation of Signaling in Asthma

Sprouty-2 哮喘信号传导的调节

• 批准号: 8630180
• 负责人: Rafeul Alam
• 金额: $ 39.63万
• 依托单位: NATIONAL JEWISH HEALTH
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-07-15 至 2018-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8630180
• 关键词: Abbreviations; Address; Affect; Allergens; Asthma; CD28 gene; CD3 Antigens; CD4 Positive T Lymphocytes; Cell Differentiation process; Cell Proliferation; Cells; Chronic; Chronic Disease; Clinical; Defect; Development; Disease; Down-Regulation; Endocytosis; Epithelial Cells; Extrinsic asthma; Feedback; Human; Impairment; In Vitro; Inflammation; Inflammatory; Knock-out; Knockout Mice; Knowledge; Ligands; MAPK3 gene; Maintenance; Mediating; Modeling; Mus; Outcome; Output; Patients; Phenotype; Play; Public Health; Recycling; Regulation; Reporting; Resolution; Role; Signal Pathway; Signal Transduction; Signaling Molecule; T-Lymphocyte; Testing; Th2 Cells; Tissues; Up-Regulation; airway hyperresponsiveness; airway inflammation; anergy; asthmatic patient; base; cell motility; cytokine; in vivo; mouse model; new therapeutic target; novel; prevent; public health relevance; receptor; response; signal processing; ubiquitin ligase

Abstract Asthma is a chronic inflammatory disease of the airways where T cells manifest a biased Th2/Th17 differentiation and a hyperactive phenotype. The latter is associated with sustained intracellular signaling. Signaling processes are usually transient due to negative homeostatic regulation. There is a knowledge gap in our understanding of mechanisms that induce sustained signaling. We propose to delineate the mechanism of induction of sustained signaling in T cells from asthma. We have reported that the signaling molecule sprouty 2 (spry 2) plays an essential role in establishing a self-sustained signaling mechanism for ERK1/2. To address this further we have generated CD4 targeted spry 2 knockout mice. Spry2-/- T cells have increased Cbl-b and decreased Nedd4. The foregoing ubiquitin ligases antagonistically regulate TCR ubiquitylation, endocytosis, degradation and thereby, control TCR signaling output. As a consequence of these receptor proximal abnormalities spry2-/-T cells have impaired signaling and proliferation. These impairments become more pronounced following CD28 engagement. Spry2-/- T cells have impaired Th2/Th17 differentiation. They are unable to mount airway inflammation, hyperreactivity and remodeling in a mouse model of asthma. Based upon these preliminary results we hypothesize that spry 2 amplifies and prolongs T cell signaling by forming a tripartite regulatory network where spry 2 and Nedd4 antagonize the signal terminating action of Cbl-b. Spry2- driven amplification and sustenance of signaling is important for co-stimulation, Th2/Th17 differentiation and development of asthma. Under specific aim 1 we will examine the role of spry 2 in generating sustained signaling in T cells. We will define the scope of CD3- and especially CD28-induced signaling pathways that are regulated by spry 2. We will examine the contribution of Cbl-b and Nedd4 to the spry2 knockout phenotype. Specific aim 2 will study the importance of spry 2 for Th2 and Th17 cell differentiation in vitro and in vivo in spry2-/- mice. We will delineate the signaling mechanism by which spry 2 regulates Th2/Th17 differentiation. Under specific aim 3 we will delineate the role of spry 2 in inducing and sustaining inflammation in a mouse model of chronic asthma. We will examine if Cbl-b knockout reverses the spry2 knockout phenotype. Under specific aim 4 we will study the expression of spry 2 in CD4 T cells from asthmatic patients and examine its contribution to the hyperactive T cell phenotype and biased differentiation in asthma. These studies are important because they have uncovered a hitherto unknown regulatory network involving spry2, Cbl-b and Nedd4, which controls Th2/Th17 differentiation and development of asthma.

摘要