Sprouty-2 Regulation of Signaling in Asthma

描述（由申请人提供）：哮喘是气道的慢性炎症性疾病，其中T细胞表现出偏向的Th 2/Th 17分化和过度活跃的表型。后者与持续的细胞内信号传导有关。由于负稳态调节，信号传导过程通常是短暂的。我们对诱导持续信号传导的机制的理解存在知识缺口。我们建议描绘的机制，诱导持续的信号在T细胞哮喘。我们已经报道了信号分子sprouty 2（spry 2）在建立ERK 1/2的自我维持信号机制中起着至关重要的作用。为了进一步解决这个问题，我们已经产生了CD 4靶向的spry 2敲除小鼠。Spry 2-/- T细胞具有增加的Cbl-b和减少的Nedd 4。前述泛素连接酶拮抗性地调节TCR泛素化、内吞作用、降解，从而控制TCR信号传导输出。作为这些受体近端异常的结果，spry 2-/-T细胞具有受损的信号传导和增殖。这些损伤在CD 28参与后变得更加明显。Spry 2-/- T细胞具有受损的Th 2/Th 17分化。他们不能在哮喘小鼠模型中增加气道炎症、高反应性和重塑。基于这些初步结果，我们假设spry 2通过形成三方调节网络来放大和抑制T细胞信号传导，其中spry 2和Nedd 4拮抗Cbl-b的信号终止作用。Spry 2驱动的信号放大和维持对于共刺激、Th 2/Th 17分化和哮喘的发展是重要的。在具体目标1下，我们将研究spry 2在T细胞中产生持续信号传导的作用。我们将定义受spry 2调节的CD 3（尤其是CD 28）诱导的信号通路的范围。我们将检查Cbl-b和Nedd 4对spry 2敲除表型的贡献。具体目标2将研究spry 2对spry 2-/-小鼠体外和体内Th 2和Th 17细胞分化的重要性。我们将阐明spry 2调节Th 2/Th 17分化的信号转导机制。在具体目标3中，我们将描述spry 2在慢性哮喘小鼠模型中诱导和维持炎症的作用。我们将检查Cbl-b敲除是否逆转spry 2敲除表型。在具体目标4下，我们将研究哮喘患者CD 4 T细胞中spry 2的表达，并检查其对哮喘中过度活化T细胞表型和偏向分化的贡献。这些研究很重要，因为它们揭示了一个迄今未知的涉及spry 2、Cbl-b和Nedd 4的调控网络，该网络控制着Th 2/Th 17分化和哮喘的发展。

DESCRIPTION (provided by applicant): 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 delineae 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.