Molecular Pathogenesis of Immune Dysfunction In Wiskott-Aldrich-Syndrome

描述(由申请人提供)：Wiskott-Aldrich综合征(WASS)是一种X连锁免疫缺陷，由WAS蛋白(WASP)基因突变引起，是T辅助细胞(Th)正常运作所必需的，对塑造适应性免疫反应至关重要。疾病的临床严重程度从轻微到严重不等，即使在具有相同黄蜂突变的患者中也是如此。这一系列适应性免疫功能障碍的生物学基础尚不清楚。Th：DC的相互作用启动了Th1分化的多条信号通路。经典的Th1信号通路需要在Th免疫突触(This)处形成成熟的Th1信号小体(IFN3R TCR2)，下游激活STAT1和T-bet，导致干扰素-3的转录。同时，依赖ITK的T-bet的磷酸化是Th2转录因子GATA-3失活所必需的。最后，Notch信号通路对Th1和Th2的分化均有影响。这些看似不同的信号通路是如何组织成一个功能强大的Th1发育范式的？在这项建议中，我们将检验黄蜂对TCR依赖和Notch依赖的Th1激活途径都至关重要的假设，并提出黄蜂的适配功能通过促进Notch、ITK和T-bet之间的相互作用来组织Th1发育反应。我们假设AS临床表型的严重程度反映了破坏这些相互作用的黄蜂突变所带来的Th功能障碍的程度。在目标1中，我们将检验黄蜂对于依赖TCR的Th1分化途径的正常功能至关重要的假设。目的2将验证黄蜂在Th1分化过程中对Notch信号的关键作用的假设。最后，目标3将测试假设，即临床表型的严重程度反映了Th功能障碍的程度。这些研究将为黄蜂在健康和疾病中适应性免疫反应的发展中的作用提供新的见解，这可能对开发新的治疗靶点有价值。术语摘要：Wiskott-Aldrich综合征是一种遗传性全身性免疫缺陷，由一种名为WASP的蛋白质缺陷引起，临床上表现为严重的反复感染、易擦伤和出血、自身免疫和癌症。这项研究将在分子水平上研究WASP的功能，以确定WASP上述临床并发症的原因。这些研究应该为未来设计新的治疗方法奠定基础，以治疗这种威胁生命、使人虚弱的童年疾病。

DESCRIPTION (provided by applicant): Wiskott-Aldrich syndrome (WAS) is an X-linked immune deficiency arising from mutations in the WAS protein (WASp) gene, required for the proper functioning of T helper cell (Th), important for shaping the adaptive immune response. The clinical severity of disease can range from mild to severe, even in patients with the identical WASp mutation. The biological basis for this range of adaptive immune dysfunction is not known. The Th:DC interaction initiates multiple signaling pathways specific for Th1 differentiation. The classical Th1 signaling pathway requires the formation of a mature Th1-signalosome (IFN3R+TCR2) at the Th immune synapse (ThIS) and downstream activation of STAT1 and T-bet, leading to transcription of IFN-3. In parallel, ITK-dependent phosphorylation of T-bet is required for deactivation of GATA-3, the Th2 transcription factor. Finally, the Notch signaling pathway has effects on both Th1 and Th2 differentiation. How are these seemingly disparate signaling pathways organized into a functional Th1 developmental paradigm? In this proposal we will test the hypothesis that WASp is critical for both TCR-dependent and Notch-dependent pathways of Th1 activation, and propose that the adaptor function of WASp organizes Th1 developmental responses by fostering interactions between Notch, ITK and T-bet. We posit that the severity of WAS clinical phenotype mirrors the degree of Th dysfunction imparted by WASp mutations that disrupt these interactions. In Aim 1, we will test the hypothesis that WASp is critical for the proper functioning of the TCR-dependent pathway of Th1 differentiation. Aim 2 will test the hypothesis that WASp is critical for Notch-signaling in Th1 differentiation. Finally, Aim 3 will test the hypothesis that the severity of WAS clinical phenotype is mirrored in the degree of Th dysfunction. These studies should provide new insights into the function of WASp in the development of the adaptive immune response in health and disease, which may be of value in developing new therapeutic targets. Lay-term summary: Wiskott-Aldrich syndrome (WAS) is a genetically transmitted systemic immune deficiency resulting from a defect in a protein called WASP and manifesting clinically in severe recurrent infections, easy bruising and bleeding, autoimmunity, and cancers. The studies in this proposal will examine the function of WASP at the molecular level to determine the causes of the above clinical complications of WAS. These studies should lay the foundation for designing novel therapies in the future, for this life-threatening, debilitating disease of the childhood.