Mechanisms of IgE mediated FceRI regulation

（申请人？摘要）IgE/FceRI网络是过敏性疾病的核心， 炎症，因此可能参与支气管炎的发生。 高反应性和哮喘FceRI表面表达的水平是 由循环IgE水平控制。这项规定具有很大的 因为增加的FceRI表达转化为 增强效应器功能。此外，最近的抗IgE临床试验 强调了这种调节的重要性，显示嗜碱性粒细胞减少， 效应子功能与相应降低的FceRI表达。然而，在这方面， 对于IgE如何调节FceRI表达还不清楚。我们建议进一步 通过以下四个方面了解IgE介导的FceRI调节 目标。具体目的1：表征IgE介导的FceRI上调的过程。 在这个目标中，我们将剖析IgE介导的过程， FceRI的上调，确定所涉及的机制。具体目标二： 阐明经典β对IgE介导的FceRL上调的影响 在这一目标中，我们将跟进我们的初步数据，表明IgE介导的 FceRI的上调在IgG2中显著大于在IgG2中。 体外表达β γ 2的细胞。我们将确定 （一）造成这种差异的原因。我们还将分析 γ-谷氨酰胺2与α-谷氨酰胺2上调的生理意义 小鼠最后，我们将确定β基因中已知的多态性是否 影响IgE介导的FceRI上调。具体目标3：阐明 β基因的新产物对IgE介导的 我们的初步数据显示，人类β基因产生两个 共表达并编码两种蛋白质的替代转录物， 相反的功能：经典的β，和一个新描述的截短蛋白， betaT我们将确定β T是否影响IgE介导的调节。我们将 还评估产生betaT的选择性剪接是否受到 IgE介导的调节。最后，我们将确定是否已知 β基因的多态性影响β的选择性剪接。 具体目标4：剖析FceRI的最小结构， IgE介导的调节。在确定了分子机制之后， 在IgE介导的FcERI调节的基础上，我们将确定最小的 这些机制的基础。我们将鉴定出 α链中的序列，其是通过 使用大量突变和嵌合受体。此外，我们将 使用类似的策略确定伽马是否影响上调。 最后，我们将验证上调所需的关键域 影响目的1中揭示的IgE介导的FceRI上调的机制。 总之，这些分析将提供重要的见解， 控制IgE介导的调节的过程和分子参数 FceRI表达。

(Applicant?s Abstract) The IgE/FceRI network is central to allergic inflammation and as such may be involved in the genesis of bronchial hyperresponsiveness and asthma. The level of FceRI surface expression is controlled by the level of circulating IgE. This regulation has great physiological significance since increased FceRI expression translates into enhanced effector function. Furthermore, recent anti-IgE clinical trails have underscored the importance of this regulation, showing decreased basophil effector function with corresponding decreased FceRI expression. However, nothing is known of how IgE regulates FceRI expression. We propose to further the understanding of IgE-mediated FceRI regulation through the four following aims. Specific Aim 1: Characterize the process of IgE-mediated FceRI up-regulation. In this aim we will dissect the process of IgE-mediated up-regulation of FceRI, determining the mechanism(s) involved. Specific Aim 2: Elucidate the impact of classical beta on IgE-mediated up-regulation of FceRL In this aim, we will follow-up on our preliminary data that show IgE-mediated up-regulation of FceRI is significantly greater in alphagamma2 than in alpha beta gamma2 expressing cells in vitro. We will determine the molecular mechanism(s) that underlie this difference. We will also analyze the physiolgical significance of alphagamma2 vs. alphabetagamma2 up-regulation in mice. Finally, we will determine whether known polymorphisms in the beta gene have an impact on IgE-mediated FceRI up-regulation. Specific Aim 3: Elucidate the impact of a new product of the beta gene on IgE-mediated up-regulation of FceRL Our preliminary data show that the human beta gene gives rise to two alternative transcripts that are co-expressed and encode two proteins with opposing functions: classical beta, and a newly described truncated protein, betaT. We will determine if betaT impacts IgE- mediated regulation. We will also assess if the alternative splicing to produce betaT is affected by the IgE-mediated regulation. Finally, we will ascertain whether known polymorphisms in the beta gene affect the alternative splicing of beta. Specific Aim 4: Dissect the minimal structure of FceRI required for IgE-mediated regulation. Having identified the molecular mechanism(s) that underlie IgE-mediated regulation of FcERI, we will determine the minimal structural basis for these mechanisms. We will identify the amino acid sequences in the alpha chain that are necessary to mediate up-regulation by using a number of mutated and chimeric receptors. In addition, we will determine if gamma impacts up-regulation utilizing a similar strategy. Finally, we will verify that the critical domains required for up-regulation affect the mechanism(s) of IgE-mediated FceRI up-regulation revealed in Aim 1. Taken together, these analyses will provide significant insights into the process and molecular parameters that control the IgE-mediated regulation of FceRI expression.