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

项目概要 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。发病率 近几十年来，T1D 在全球范围内不断增加。遗传易感性和环境因素 交互式地促进 T1D 的发展。人类遗传学研究已确定超过 50 个基因座 与 T1D 显着相关。然而，我们对这些区域内潜在基因的了解 独立或协同影响细胞过程，导致胰岛素产生的破坏 胰腺β细胞是不完整的。为了填补这一空白，我们使用基于核酸酶的方法来靶向小鼠 直接在非肥胖糖尿病 (NOD) 小鼠中直接研究人类 T1D 候选基因的直系同源物，以寻求功能 它们在糖尿病发展中的作用的证据。在这项工作中，我们发现 Il27 对于糖尿病至关重要 NOD 小鼠的发育。 CD4 和 CD8 T 细胞都是 T1D 发展所必需的。 β细胞如何 在 T1D 进展过程中，自身反应性 T 细胞被激活、积累并维持其效应功能 没有被完全定义。在此应用中，我们将确定 IL-27 影响 T1D 的机制 通过其对 T 细胞的直接影响。 IL-27 通过与其受体结合发挥多种免疫功能 （IL-27Ra 和 gp130 异二聚体）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，对糖尿病具有完全抵抗力，表明 IL-27 信号传导的关键作用 在 T1D 发展中。我们的研究还表明，巨噬细胞和/或 DC 产生的 IL-27 足以驱动 T1D，但他们对 IL-27 的反应对于糖尿病的发展并不重要。 T细胞总数 从 NOD 和 NOD.Il27-/- 小鼠中分离出来的小鼠在转移到 IL-27 充足的环境中时同样会导致糖尿病 NOD.Rag1-/- 接收者。因此，β细胞自身反应性T细胞存在于NOD.Il27-/-小鼠中，但它们的致病性 在没有 IL-27 的情况下不能诱导或维持活性。相比之下，从 NOD.Il27ra-/- 小鼠不会在 NOD.Rag1-/- 受体中诱导 T1D，表明 T 细胞中的直接 IL-27 信号传导 细胞促进糖尿病的发展。使用混合 CD4 和 CD8 T 细胞转移方法，我们进一步 证明 CD4 和 CD8 T 细胞中的 IL-27 信号传导对于 T1D 进展很重要。一 CD4 T 细胞重要的致糖尿病活性是为自身反应性 CD8 T 细胞提供帮助，这些细胞直接 识别并杀死产生胰岛素的β细胞。因此，我们推测 IL-27 对于 通过直接作用于 β 细胞自身反应性 CD8 T 细胞来积累和持续效应功能 并间接通过增强 CD4 T 细胞的辅助功能。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 细胞。 (2) 确定 CD4 T 细胞中 IL-27 信号传导支持自身反应性 CD8 T 的功能 T1D 中的效应器。完成拟议的实验将为未来的人类研究奠定框架。

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.