Shaping diabetogenic T cells by IL-27 in type 1 diabetes

项目总结 1型糖尿病(T1D)是一种终生疾病，需要每天注射外源性胰岛素。的发病率。 近几十年来，T1D在全球范围内一直在增长。遗传易感性与环境因素 互动地为T1D发展做出贡献。人类遗传学研究已经确定了50多个基因座 与T1D显著相关。然而，我们对这些区域内潜在基因的了解 独立地或协同地影响细胞过程，导致胰岛素产生的破坏 胰岛β细胞是不完整的。为了填补这一空白，我们使用了基于核酸酶的方法来靶向小鼠 人类T1D候选基因在非肥胖糖尿病(NOD)小鼠中的同源基因寻找功能 它们在糖尿病发展中所起作用的证据。在这项工作中，我们发现IL27对糖尿病是必不可少的 NOD小鼠的发育。CD4和CD8T细胞都是T1D发育所必需的。如何使用Beta-cell 自身反应性T细胞在T1D进程中被激活、积累并维持其效应功能 没有完全定义。在本申请中，我们将确定IL-27影响T1D的机制 通过它对T细胞的直接作用。IL-27通过与其受体结合发挥多种免疫功能 (IL-27Ra和gp130异源二聚体)在许多免疫细胞上表达，包括巨噬细胞、树突状细胞 (DC)、B细胞和T细胞。我们在这里分别展示了NOD.Il27-/-和NOD.Il27ra-/-小鼠 缺乏IL-27及其受体的人对糖尿病完全抵抗，这表明IL-27信号的关键作用 在T1D开发中。我们的研究还表明，巨噬细胞和/或DC产生的IL-27 足以导致T1D，但它们对IL-27的反应对糖尿病的发生并不重要。T细胞总数 从NOD和NOD分离的IL27-/-小鼠在转移到IL-27充足的情况下也有类似的致糖尿病作用 NOD.Rag1-/-收件人。因此，在NOD.Il27-/-小鼠中存在β细胞自身反应性T细胞，但它们的致病作用 在没有IL-27的情况下，不能诱导或维持活性。相比之下，从中国分离的T细胞总数 NOD.Il27ra-/-小鼠不能在NOD.Rag1-/-受体中诱导T1D，这表明T细胞中直接的IL-27信号转导 细胞促进糖尿病的发展。使用混合的CD4和CD8 T细胞转移方法，我们进一步 证明了T细胞中的IL-27信号在T1D的进展中起着重要作用。一 CD4T细胞的重要促糖尿病活性是为自身反应性CD8T细胞提供帮助 识别并杀死产生胰岛素的β细胞。因此，我们假设IL-27对 直接作用于β细胞自身反应性CD8 T细胞的蓄积和持续效应功能 间接通过增强CD4T细胞的辅助性功能。我们提出以下目标来测试这一点 假设。(1)确定IL-27内在促进β细胞自身反应性CD8 T的机制 T1D中的细胞。(2)检测CD4T细胞中IL-27信号对自身反应性CD8T的支持作用 T1D中的效应器。拟议中的实验的完成将为未来的人体研究奠定基础。

PROJECT SUMMARY Type 1 diabetes (T1D) is a life-long disease requiring daily injections of exogenous insulin. The incidence of T1D has been increasing worldwide in recent decades. Genetic susceptibility and environmental factors interactively contribute to T1D development. Human genetic studies have identified more than 50 loci significantly linked to T1D. However, our knowledge of the underlying genes within these regions that independently or cooperatively influence cellular processes leading to the destruction of insulin producing pancreatic beta-cells is incomplete. To fill this gap, we used nuclease based approaches to target the murine orthologs of human T1D candidate genes directly in nonobese diabetic (NOD) mice to seek functional evidence of their roles in diabetes development. In this effort, we discovered that Il27 is essential for diabetes development in NOD mice. Both CD4 and CD8 T cells are required for T1D development. How beta-cell autoreactive T cells are activated, accumulate, and maintain their effector function during T1D progression has not been fully defined. In this application we will determine the mechanisms by which IL-27 impacts T1D through its direct effects on T cells. IL-27 exerts diverse immunological functions by binding to its receptors (IL-27Ra and gp130 heterodimers) expressed on many immune cells, including macrophages, dendritic cells (DCs), B cells, and T cells. We showed here that both NOD.Il27-/- and NOD.Il27ra-/- mice, respectively lacking IL-27 and its receptor, were completely resistant to diabetes, indicating a critical role of IL-27 signaling in T1D development. Our studies also demonstrated that IL-27 produced by macrophages and/or DCs was sufficient to drive T1D but their responses to IL-27 were not important for diabetes development. Total T cells isolated from NOD and NOD.Il27-/- mice were similarly diabetogenic when transferred into IL-27-sufficient NOD.Rag1-/- recipients. Thus, β-cell autoreactive T cells are present in NOD.Il27-/- mice, but their pathogenic activity cannot be induced or sustained in the absence of IL-27. In contrast, total T cells isolated from NOD.Il27ra-/- mice did not induce T1D in NOD.Rag1-/- recipients, indicating that direct IL-27 signaling in T cells promotes diabetes development. Using a mixed CD4 and CD8 T cell transfer approach, we further demonstrated that IL-27 signaling in both CD4 and CD8 T cells is important for T1D progression. One important diabetogenic activity of CD4 T cells is to provide help to autoreactive CD8 T cells that directly recognize and kill insulin-producing beta-cells. Therefore, we hypothesize that IL-27 is important for the accumulation and sustained effector function of beta-cell autoreactive CD8 T cells by directly acting on them and indirectly through enhancing the helper function of CD4 T cells. We propose the following aims to test this hypothesis. (1) To identify the mechanisms by which IL-27 intrinsically promotes beta-cell autoreactive CD8 T cells in T1D. (2) To determine the function of IL-27 signaling in CD4 T cells for supporting autoreactive CD8 T effectors in T1D. Completion of the proposed experiments will lay the framework for future human studies.