The role of IL-27/Lag3 axis in regulating Foxp3+ regulatory T cell function

摘要 Foxp3+CD4T细胞(Tregs)在调节免疫耐受中起着关键作用。Treg中的缺陷 生成和/或功能与不受控制的免疫激活直接相关，导致 自身免疫性疾病的发展。然而，Tregs表达的确切机制是 功能仍不清楚。多发性硬化症(MS)是一种髓鞘抗原特异性自身免疫 髓鞘抗原特异性Th17型CD4介导的中枢神经系统炎症 T细胞。实验性自身免疫性脑脊髓炎(EAE)是一种具有相同临床特征的动物模型 和组织学特征，被广泛用于研究MS的发病机制以及 开发一种治疗这种疾病的方法。越来越多的证据表明Treg函数可能是 多发性硬化症患者或携带EAE的小鼠的调节失调。因此，确定改善Treg的途径 开发一种针对Tregs的潜在疗法是一个具有临床重要性的问题。少校 本应用的目的是测试IL-27在Treg功能中的作用。我们最近报道了IL-27 Tregs中的信号在抑制肠道中Th17型炎症方面起着至关重要的作用。我们 利用一种新开发的Treg特异性IL27ra/-动物，发现Treg特异性IL-27R缺乏 导致严重的EAE。中枢神经系统浸润的CD4T细胞产生促炎细胞因子 在IL27ra-/-Tregs存在下不受控制，而IL-10+CD4T细胞参与调节 炎症反应保持不变。全基因组微阵列分析显示IL-27 刺激Tregs诱导LAG3，一种与T细胞负调节有关的类似CD4的分子 激活。然后，我们使用了一种新的Treg特异性LAG3/-动物，发现它们也会发展成严重的 提示LAG3的Treg表达可能在介导IL-27诱导的Treg功能中起关键作用。 最后，IL-27在Treg体内的预刺激显著增强了体外和体内的抑制功能 活着。总体假设是IL-27控制EAE和LAG3期间Treg抑制功能 IL-27信号的诱导在介导IL-27对Tregs的作用中起着关键作用。我们还建议 IL-27预刺激可改善Treg的抑制功能，逆转正在进行中 中枢神经系统的炎症。提出了三个具体目标。Aim#1将测试IL-27信号的作用 论EAE期间的Treg功能。目的2测试LAG3在IL-27介导的血管紧张素转换酶调控中的作用。 Treg函数。目标#3将测试IL-27预刺激的Tregs有效逆转的机制 持续的神经炎症。我们预计，这项研究的结果将确定新的 IL-27通过LAG3调节Treg功能以下调炎症反应的机制 中枢神经系统。完成建议的研究将为发展新的 针对Tregs中IL-27/LAG3轴的治疗MS和其他慢性炎症的策略 纸巾。

Abstract Foxp3+ CD4 T cells (Tregs) play a key role in regulating immunity and tolerance. Defects in Treg generation and/or functions are directly associated with uncontrolled immune activation leading to the development of autoimmune diseases. Yet, the precise mechanisms by which Tregs express the functions remain unclear. Multiple sclerosis (MS) is a myelin antigen specific autoimmune inflammation of the central nervous system (CNS) mediated by myelin antigen specific Th17 type CD4 T cells. Experimental autoimmune encephalomyelitis (EAE) is an animal model that shares clinical and histological features with MS, and is widely used to investigate the pathogenesis as well as to develop an approach to treat the disease. Increasing evidence suggests that Treg function may be dysregulated in MS patients or EAE bearing mice. Thus, identifying pathways that improve Treg function is an issue of clinical importance to develop a potential therapy targeting Tregs. The major goal of this application is to test the role of IL-27 in Treg function. We recently reported that IL-27 signaling in Tregs plays an essential role in suppressing Th17 type inflammation in the intestine. We utilized a newly developed Treg-specific Il27ra-/- animal and found that Treg-specific IL-27R deficiency results in a severe EAE. CNS infiltrating CD4 T cells producing proinflammatory cytokines were uncontrolled in the presence of Il27ra-/- Tregs, while IL-10+ CD4 T cells implicated in regulation of inflammatory responses remained unchanged. Genome wide microarray analysis revealed that IL-27 stimulation in Tregs induces Lag3, a CD4 like molecule implicated in negative regulation of T cell activation. We then used a novel Treg-specific Lag3-/- animal and found that they also develop severe EAE, suggesting that Treg expression of Lag3 may be critical to mediate IL-27-induced Treg function. Finally, IL-27 prestimulation in Tregs significantly enhances suppressive function both in vitro and in vivo. The overall hypothesis is that IL-27 controls Treg suppressive function during EAE and that Lag3 induced by IL-27 signaling plays a key role in mediating IL-27 effect on Tregs. We also propose that the suppressive function of Tregs can be improved by IL-27 prestimulation, reversing ongoing inflammation in the CNS. Three specific aims are proposed. Aim #1 will test the role of IL-27 signaling on Treg function during EAE. Aim #2 will test To test the role of Lag3 during IL-27-mediated control of Treg function. Aim #3 will test the mechanisms by which IL-27 prestimulated Tregs efficiently reverse ongoing neuroinflammation. We anticipate that the results from this study will identify novel mechanisms by which IL-27 modulates Treg function via Lag3 to downregulate inflammation in the CNS. Completing the proposed studies will provide an important basis for the development of new strategies targeting the IL-27/Lag3 axis in Tregs to treat MS, and chronic inflammation in other tissues.