Regulation and Function of Interleukin-7 in Primary Sjogrens Syndrome

描述(申请人提供)：干燥综合征(SjS)是一种慢性自身免疫性疾病，影响2-400万美国人，极大地影响患者的健康和福祉。SJS以慢性炎症和唾液腺、泪腺功能障碍为特征，以口干、眼干为主要症状。自身反应性T细胞和T细胞衍生的细胞因子在SjS的发生发展中起重要作用。白介素7(IL-7)通过增强T辅助细胞(Th)1和T细胞毒(TC)1反应，在多种自身免疫性疾病中发挥重要的致病作用。据报道，原发性SjS患者的IL-7水平升高。我们的初步研究表明，在小鼠疾病模型中，外源性和内源性IL-7都促进了SjS的发生和发展，并伴随着Th1和Tc1反应的增强。此外，我们还发现干扰素-α和干扰素-γ能够诱导人唾液腺细胞系产生IL-7。在本研究中，我们将对IL-7及其靶点在原发SjS的发生和持续中的体内功能进行表征，并确定导致SjS过度产生IL-7的信号和分子途径。在本研究的目的1中，我们将评估IL-7和IL-7诱导的Th1/Tc1细胞因子在SjS发病过程中的体内作用以及在SjS发病后持续的作用。我们将使用体内抗体阻断的方法来消除C57BL/6疾病特定阶段的IL-7、干扰素-γ或肿瘤坏死因子-α的活性。在目标2中，我们将确定IL-7增强Th1/Tc1应答的分子机制。我们将使用几种基因突变小鼠、体内抗体阻断和体外基因沉默的方法来确定T-bet、PD-1和TRAF1在IL-7介导的Th1/Tc1反应增强中的作用。此外，我们将与佛罗里达大学的Seunghee Cha博士合作，使用体外T细胞刺激培养和基因沉默方法，在SjS患者和健康对照组的人类T细胞中验证这些结果。在目标3中，我们将描述导致SjS唾液腺细胞过度产生IL-7的信号通路。我们将使用几只基因突变的小鼠，一种人类上皮细胞系和一种 结合体内和体外方法表征干扰素-α和干扰素-γ在SJS环境中促进唾液腺细胞产生IL-7的体内作用。该项目的完成将为以IL-7和Th1/Tc1细胞因子为靶点的SjS新的诊断和治疗策略的开发提供重要的信息和基础。

DESCRIPTION (provided by applicant): Sjögren's syndrome (SjS) is a chronic autoimmune disease that affects 2-4 million Americans and greatly affects the health and well-being of the patients. SjS is characterized by chronic inflammation and dysfunction of the salivary and lacrimal glands with dry mouth and dry eyes as the primary symptoms. Autoreactive effector T cells and T cell-derived cytokines play a crucial role in the development and onset of SjS. Interleukin-7 (IL-7) plays a crucial pathogenic role in multiple autoimmune diseases through enhancing T helper (Th) 1 and T cytotoxic (Tc) 1 responses. Elevated IL-7 levels were reported in primary SjS patients. Our preliminary studies showed that both exogenous and endogenous IL-7 promotes the development and onset of SjS in a mouse disease model, which is accompanied by enhanced Th1 and Tc1 responses. In addition, we found that IFN-α and IFN-γ can induce IL-7 production in a human salivary gland cell line. In the current study, we will characterize the in vivo functions of IL-7 and its targets in the development and the persistence of primary SjS, and define the signaling and molecular pathways that cause excessive IL-7 production in SjS. In Aim 1 of this study, we will assess the in vivo functions of IL-7 and IL-7-induced Th1/Tc1 cytokines in the development of SjS and in the persistence of SjS after disease onset. We will use in vivo antibody blockade approach to abrogate IL-7, IFN-γ or TNF-α activity at specific stages of the disease in C57BL/6.NOD-Aec1Aec2 mice, a well-defined model of primary SjS. In Aim 2, we will determine the molecular mechanisms by which IL-7 enhances Th1/Tc1 responses. We will use several genetically mutant mice, in vivo antibody blockade and in vitro gene-silencing approaches to determine the role of T-bet, PD-1 and TRAF1 in IL-7-mediated enhancement of Th1/Tc1 responses. Moreover, we will collaborate with Dr. Seunghee Cha at the University of Florida to validate these results in human T cells from SjS patients and healthy controls, using in vitro T cell stimulation cultures and gene-silencing approaches. In Aim 3, we will characterize the signaling pathways that cause excessive IL-7 production in salivary gland cells in SjS. We will use several genetically mutant mice, a human epithelial cell line and a combination of in vivo and in vitro approaches to characterize the in vivo role of IFN-α and IFN-γ in enhancing IL-7 production from salivary gland cells in the SjS setting. Completion of this project will provide crucial information and foundation for the development of novel diagnostic and therapeutic strategies for SjS by targeting IL-7 and Th1/Tc1 cytokines.