c-Ab1 in the allergic inflammatory lung disease

描述（由申请人提供）：辅助性T细胞2型（Th 2）细胞通过产生关键细胞因子，包括白细胞介素（IL）-4，IL-5和IL-13，对引起过敏性炎症性肺病如哮喘至关重要。介导幼稚CD 4 + T细胞在被特异性抗原刺激后分化为Th 1或Th 2的分子机制仍然知之甚少。在此，我们的初步研究已经证明，c-Abl（Src家族酪氨酸激酶）功能的丧失使CD 4 + T细胞偏向于Th 2分化，因为当与c-Abl +/+ CD 4 + T细胞产生这些Th 2细胞因子相比时，c-Abl-/-CD 4 + T细胞产生IL-4、IL-5和IL-13显著增加。而c-Abl-/-CD 4 + T细胞产生Th 1细胞因子的能力则受到抑制。有趣的是，我们发现，在c-Abl-/- T细胞中，Th 1-linage转录因子T-bet的酪氨酸磷酸化显著降低，表明c-Abl通过磷酸化T-bet调节Th 1/Th 2分化，至少是其中一种机制。为了支持这一点，我们发现，过度表达c-Abl，而不是其激酶死亡突变体，诱导T-bet的酪氨酸磷酸化。c-Abl在Jurkat T细胞中的表达激活IFN？报道子活性并抑制IL-4报道子。这些结果表明，c-Abl通过激活T-bet维持Th 1和Th 1分化之间的平衡，c-Abl功能的丧失增强Th 1但损害Th 1分化。因此，c-Abl缺陷可引起小鼠过敏性肺部炎症。我们将通过解决以下两个具体目标来检验这一假设：目标1。c-Abl如何调节Th 1/Th 2分化？c-Abl磷酸化并由此激活Th 1谱系转录因子T-bet的事实表明，c-Abl通过靶向T-bet调节Th 1/Th 2分化。我们将进一步研究c-Abl是如何调节T-bet转录活性的。除了T-bet，其他一些转录因子和信号分子也参与调节CD 4+辅助细胞分化;因此，我们也将确定c-Abl是否通过靶向其他分子来调节T细胞分化。目标2. c-Abl缺乏会导致小鼠哮喘吗？Th 2细胞因子，特别是IL-4和IL-13，在小鼠和人类的哮喘发展中起着至关重要的作用。通过c-Abl-/-CD 4 + T细胞的Th 2细胞因子的产生被上调的事实表明c-Abl-/-小鼠可能潜在地发展哮喘。我们将使用实验性哮喘模型来确定c-Abl缺乏如何影响：1.气道阻力，2. IgE的产生，3.气道炎症及炎性细胞迁移; 4.气道高反应性我们预计c-Abl-/-小鼠比野生型小鼠产生更严重的过敏反应。公共卫生相关性：大约有1000万美国人患有哮喘，这是美国最常见和最昂贵的疾病之一（每年超过180亿美元的医疗费用）。过敏性哮喘是哮喘的最常见形式，其由Th 2细胞因子产生升高引起。从我们提出的研究结果应该揭示一个以前未知的机制，调节Th 2细胞因子的产生。此外，c-Abl作为调节剂可能是控制哮喘等疾病中过敏性炎症的潜在治疗靶点。

DESCRIPTION (provided by applicant): T helper type 2 (Th2) cells are crucial for causing the allergic inflammatory lung diseases such as asthma, by producing key cytokines, including interleukin (IL)-4, IL-5 and IL-13. The molecular mechanisms that mediate naive CD4+ T cells, after they are stimulated by specific antigens, to differentiate into Th1 or Th2 are still poorly understood. Here, our preliminary studies have demonstrated that loss of the functions of c-Abl, a Src family tyrosine kinase, skews CD4+ T cells to Th2 differentiation because the production of IL-4, IL-5 and IL-13 by c-Abl-/- CD4+ T cells is dramatically increased when compared to the production of these Th2 cytokines by c-Abl+/+ CD4+ T cells. While the production of Th1 cytokines from c-Abl-/- CD4+ T cells was impaired. Interestingly, we found that the tyrosine phosphorylation of Th1-linage transcription factor, T-bet, is dramatically reduced in c-Abl-/- T cells, suggesting that c-Abl regulates Th1/Th2 differentiation by, at least one of the mechanisms, phosphorylating T-bet. To support this, we found that over-expression of c-Abl but not its kinase-dead mutant, induced the tyrosine phosphorylation of T-bet. Expression of c-Abl in Jurkat T cells activates IFN? reporter activity and suppresses IL-4 reporters. These results indicate that c-Abl keeps the balance between Th1 and Th1 differentiation by activating T-bet, and loss of c-Abl functions enhances Th1 but impairs Th1 differentiation. Therefore, c-Abl-deficiency may cause allergic lung inflammations in mice. We will test this hypothesis by addressing the following two Specific Aims: Aim 1. How does c-Abl regulate Th1/Th2 differentiation? The fact that c-Abl phosphorylates, and thereby activates the Th1-lineage transcriptional factor T-bet, indicates that c-Abl regulates Th1/Th2 differentiation by targeting T-bet. We will further examine how T-bet transcription activity is regulated by c-Abl. Besides T-bet, several other transcription factors and signaling molecules are also involved in regulating CD4+ helper cell differentiation; thus, we will also determine whether c-Abl regulates T cell differentiation by targeting other molecules. Aim 2. Does c-Abl-deficiency cause asthma in mice? Th2 cytokines, particularly IL-4 and IL-13, plays a crucial role in asthma development in mice as well as in humans. The fact that the production of Th2 cytokines by c-Abl-/- CD4+ T cells is upregulated suggests that c-Abl-/- mice may potentially develop asthma. We will use an experimental asthma model to determine how c-Abl deficiency affects: 1. the airway resistance, 2. the IgE production, 3. the airway inflammation and the migration of inflammatory cells and 4. airway hyperresponsiveness. We anticipate that c-Abl-/- mice develop more severe allergic responses than wild-type mice. PUBLIC HEALTH RELEVANCE: About 10 million Americans have asthma, one of the most common and costly (over $18 billion annual health care costs) illnesses in the United States. Allergic asthma is the most common form of asthma, which is caused by elevated Th2 cytokine production. The results from our proposed research should uncover a previously unknown mechanism in regulating Th2 cytokine production. Further, c-Abl as a regulator might be a potential therapeutic target for controlling allergic inflammation in diseases such as asthma.