Sprouty-2 Regulation of Signaling in Asthma

摘要 哮喘是一种气道慢性炎症性疾病，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。存在知识差距， 我们对诱导持续信号的机制的理解。我们建议描述的机制， 哮喘T细胞中持续信号的诱导。我们已经报道了信号分子发芽 2（spry 2）在建立ERK 1/2的自我维持信号传导机制中起着至关重要的作用。解决 这进一步产生了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NED 4。前述泛素连接酶拮抗性调节TCR泛素化，内吞作用， 降解，从而控制TCR信号输出。由于这些受体近端 spry 2-/-T细胞的异常具有受损的信号传导和增殖。这些缺陷变得更加 在CD 28接合后出现。Spry 2-/- T细胞具有受损的Th 2/Th 17分化。他们是 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 根据这些初步结果，我们假设spry 2通过形成一个特异性的信号通路来放大和抑制T细胞信号传导。 三重调控网络，其中spry 2和Nedd 4拮抗Cbl-b的信号终止作用。Spry2- 信号的驱动扩增和维持对于共刺激、Th 2/Th 17分化和 哮喘的发展。在具体目标1下，我们将研究spry 2在产生持续的 T细胞中的信号传导。我们将定义CD 3，尤其是CD 28诱导的信号通路的范围， 由SPRY 2调节。我们将研究Cbl-b和Nedd 4对spry 2敲除的贡献。 表型具体目标2将研究spry 2对体外Th 2和Th 17细胞分化的重要性， 在SPRY 2-/-小鼠体内。我们将描述spry 2调节Th 2/Th 17的信号转导机制 分化在具体目标3中，我们将描述spry 2在诱导和维持炎症中的作用。 在慢性哮喘小鼠模型中。我们将检查Cbl-b敲除是否逆转了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 并检测其对哮喘中过度活跃的T细胞表型和偏向性分化的作用。这些 研究是重要的，因为它们揭示了迄今未知的涉及SPRY 2的调节网络， Cbl-b和Nedd 4，其控制哮喘的Th 2/Th 17分化和发展。

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.