Sprouty-2 Regulation of Signaling in Asthma

摘要 哮喘是一种慢性呼吸道炎症性疾病，T细胞表现为偏向Th2/Th17 分化和高度活跃的表型。后者与持续的细胞内信号传递有关。 由于负的体内平衡调节，信号传递过程通常是短暂的。在……方面存在知识差距 我们对诱导持续信号传递机制的理解。我们建议描述以下机制： 哮喘患者T细胞持续信号的诱导。我们已经报道过信号分子萌芽 2(Spry 2)在建立ERK1/2自我维持的信号机制中起着至关重要的作用。 在此基础上，我们又产生了针对CD4的Spry2基因敲除小鼠。SPRY2-/-T细胞增加了Cbl-b和 减少Nedd4。上述泛素连接酶拮抗地调节TCR泛素化、内吞作用， 从而控制TCR信令输出。作为这些近端受体的结果 SPRY2-/-T细胞的异常损害了信号和增殖。这些损伤变得更多 在CD28订婚后宣布。SPRY2-/-T细胞损害了Th2/Th17的分化。他们是 不能在哮喘小鼠模型中增加呼吸道炎症、高反应性和重塑。基座 根据这些初步结果，我们假设spry 2通过形成一种 三方调控网络，其中spry 2和Nedd4拮抗Cbl-b的信号终止作用。春运2- 信号的驱动放大和维持对于共刺激、Th2/Th17分化和 哮喘的发展。在特定目标1下，我们将研究SPRY 2在生成持续的 T细胞中的信号。我们将定义CD3，特别是CD28诱导的信号通路的范围 我们将研究Cbl-b和Ned4在SPRY2基因敲除中的作用 表型。特异性目标2将研究Spry 2在体外对Th2和Th17细胞分化的重要性 在SPRY2-/-小鼠体内。我们将描述SPRY 2调节Th2/Th17的信号机制 差异化。在特定目标3下，我们将描述spry 2在诱导和维持炎症中的作用。 在慢性哮喘的小鼠模型中。我们将检查Cbl-b基因敲除是否逆转了SPRY2基因敲除 表型。在特定目标4下，我们将研究哮喘患者CD4T细胞中SPRY-2的表达 并探讨其在哮喘T细胞表型过度活跃和偏向分化中的作用。这些 研究很重要，因为他们发现了一个迄今未知的涉及Spry2的调控网络， CBL-b和Nedd4，控制Th2/Th17的分化和哮喘的发生发展。

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.