Agonism of DR3 for Enhanced Treg Cell Function in IBD

项目总结 炎症性肠病(IBD)中免疫介导的慢性炎症导致红斑，通常 要求患者接受终身生物疗法治疗。最近，IBD疾病管理方面的努力已经 重点关注调节性T(Treg)细胞治疗作为传统治疗替代方案的潜力。特雷格 细胞限制对外来抗原和自身抗原的炎症反应，并可进一步分化为 在暴露于免疫刺激时有效抑制效应器Tregs(ETregs)。ETreg，尤其是那些 产生免疫抑制细胞因子白介素10(IL-10)，在人类和 小鼠结肠炎。然而，诱导并在功能上增强该子集的信号并未被很好地理解， 很大程度上是因为它们的数量有限，而且还没有合适的协议来区分它们 体外培养。在这里，我们已经确定了一种信号，可以增强体内IL-10+eTregs的扩增和维持 而且是在体外。死亡受体3(DR3或TNFRSF25)是肿瘤坏死因子受体超家族 一种由活化的T细胞结构性表达的成员，已发现既能增强又能抑制 免疫反应。我们发现，使用DR3激动剂抗体(ADR3)治疗显著 特异性增强IL-10+eTregs的增殖和细胞存活。此外，治疗极大地扩展了 在许多组织中都有Treg细胞，但其作用在肠道中最为深刻。据我们所知，观察到的 ADR3扩展IL-10产生eTregs的作用尚未被描述。这项提案将决定 DR3信号诱导肠道Tregs增加的机制(目标1)，以及aDR3的潜力 作为治疗结肠炎的药物(目标2)。我们将利用一种新型的缺乏DR3的转基因小鼠模型 具体地说，在Treg中了解DR3信号在肠道Treg功能中所起的作用 状态和发炎的结肠中。通过使用我们的IL-10和Foxp3双报告小鼠，我们将能够分层 通过IL-10能力的Treg群体，这将使我们能够表征DR3 差异化地增强Treg细胞亚群。我们的中心假设是DR3信号的影响是双重的 它：(1)为效应表型启动Treg细胞；以及(2)制定影响eTreg的特定程序 生存、稳定和功能。了解这一途径如何增强Treg细胞的功能将具有广泛的- 不仅在IBD领域，而且在一些免疫介导的疾病的管理中也产生了影响 疾病。

PROJECT SUMMARY The immune-mediated, chronic inflammation in inflammatory bowel disease (IBD) leads to flares that often require patients to be treated with life-long biologic therapy. Recently, efforts in IBD disease management have focused on the potential of regulatory T (Treg) cell-based therapy as an alternative to traditional treatments. Treg cells limit inflammatory responses to both foreign and self-antigens and can become further differentiated into potently suppressive effector Tregs (eTregs) upon exposure to immune stimuli. eTregs, especially those that produce the immunosuppressive cytokine interleukin 10 (IL-10), play a critical, mitigating role in both human and murine colitis. However, the signals that induce and functionally enhance this subset are not well understood, largely because they are limited in number and there have been no suitable protocols to differentiate them in vitro. Here, we have identified a signal that enhances the expansion and maintenance of IL-10+ eTregs in vivo and in vitro. Death receptor 3 (DR3 or TNFRSF25) is a tumor necrosis factor receptor superfamily (TNFRSF) member that is constitutively expressed by activated T cells and has been found to both enhance and suppress the immune response. We have found that treatment with an agonist antibody to DR3 (aDR3) significantly enhances the proliferation and cell survival specifically of IL-10+ eTregs. Additionally, treatment greatly expands total Treg cells in many tissues, but the effect is most profound in the intestine. To our knowledge, the observation that aDR3 expands IL-10 producing eTregs has not yet been described. This proposal will determine the mechanisms by which DR3 signaling induces increased intestinal Tregs (Aim 1), as well as the potential of aDR3 as a therapeutic in the treatment of colitis (Aim 2). We will utilize a novel transgenic mouse model that lacks DR3 specifically in Tregs to understand the role that DR3 signaling plays in intestinal Treg function in both the steady state and in the inflamed colon. By using our IL-10 and Foxp3 dual reporter mouse, we will be able to stratify Treg populations by IL-10 competency, which will allow us to characterize the mechanisms by which DR3 differentially enhances Treg cell subsets. Our central hypothesis is that the effect of DR3 signaling is two-fold in that it: (1) primes Treg cells for an effector phenotype; and (2) enacts a specific program that impacts eTreg survival, stability, and function. Understanding how this pathway augments Treg cell function will have broad- reaching implications not only in the field of IBD, but also in the management of a number of immune-mediated diseases.