Reporting IL-17 in Type 1 Diabetes

描述（由申请人提供）：1型糖尿病（T1 D）目前是一种无法治愈的疾病，因为破坏产生胰岛素的B胰岛细胞的自身免疫反应无法控制。自身反应性CD 4细胞是T1 D的关键协调因素。它们不断升级的反应最终逃脱了调节，导致胰腺急性炎症和糖尿病发作。虽然很明显，产生IFN-γ的Th 1细胞对疾病的发病机制是必不可少的，但产生IL-17的Th 17细胞是否或何时对T1 D起作用尚不清楚。分泌IL-17 A和在较小程度上分泌IL-17 F的Th 17细胞与几种自身免疫性疾病有关。我们的研究表明，IL-17 A-和IFN-g-分泌的CD 4 T细胞是不同的子集在胰腺浸润在胰岛炎阶段和T1 D发作在NOD小鼠，而IL-17 F未检测到。此外，血清IL-17 A和IFN-g水平升高预示着高血糖症的发生。我们现在发现IL-17 A + CD 4 T细胞大大加速了正常（WT）NOD小鼠的糖尿病。基于我们的发现和T1 D患者中IL-17 A+细胞的检测，我们假设Th 17细胞是T1 D发病机制的重要贡献者。然而，如果没有额外的工具，就不可能直接解决调节这些细胞的反应的机制或它们的效应子功能，这些效应子功能可以被靶向以控制自身免疫反应。我们的目标是在NOD背景下开发一种新型IL-17 A报告小鼠，该小鼠将能够在T1 D进展期间通过谱系追踪原位分析Th 17细胞的发育和反应，并且在未来的R 01资助中，我们计划继续研究T1 D中Th 17细胞的调节。我们建议使用细菌人工染色体（BAC）为基础的基因报告和基因敲入策略，以创建小鼠，这将使识别和分离的CD 4细胞，获得Il 17 a基因表达，如报告的GFP-Cre融合蛋白插入在Il 17 a基因座的表达。我们将使用双报告策略，将这些动物与Rosa 26-YFP NOD小鼠交配，以永久标记具有IL-17 A产生史的细胞。这些小鼠将为明确研究Th 17细胞对T1 D的贡献以及导致糖尿病发作的Th 1和Th 17细胞之间的潜在功能相互关系提供新的工具。识别Th 17细胞发育及其功能变化的能力将有助于设计适当的策略来控制自身侵袭性CD 4细胞，并为Th 17细胞的生物学提供新的见解。

DESCRIPTION (provided by applicant): Type 1 diabetes (T1D) is currently an incurable disease because the autoimmune response that destroys insulin-producing b islet cells cannot be controlled. Autoreactive CD4 cells are key orchestrators of T1D. Their escalating responses ultimately escape regulation, leading to acute inflammation in the pancreas and diabetes onset. While it is clear that IFN-g producing Th1 cells are essential to disease pathogenesis, whether or when IL-17-producing Th17 cells contribute to T1D is unknown. Th17 cells that secrete IL-17A and to a lesser extent IL-17F have been implicated in several autoimmune diseases. Our studies show that IL-17A- and IFN-g- secreting CD4 T cells are distinct subsets in pancreatic infiltrates during the insulitis phase and at T1D onset in NOD mice, whereas IL-17F is not detected. In addition, elevated serum levels of IL-17A and IFN-g herald the onset of hyperglycemia. We now find that IL-17A+ CD4 T cells greatly accelerate diabetes in normal (WT) NOD mice. On the basis of our findings and the detection of IL-17A+ cells in T1D patients, we hypothesize that Th17 cells are important contributors to the pathogenesis of T1D. However, without additional tools, it will not be possible to directly address mechanisms that regulate the responses of these cells or their effector functions that could be targeted to control the autoimmune response. Our goal is to develop a novel IL-17A reporter mouse on the NOD background that will enable analysis of the development and responses of Th17 cells in situ by lineage tracing during progression to T1D and, in a future R01 grant we plan to pursue studies of the regulation of Th17 cells in T1D. We propose to use bacterial artificial chromosome (BAC)-based gene reporter and gene knockin strategies to create mice that will enable identification and isolation of CD4 cells that acquire Il17a gene expression, as reported by expression of a GFP-Cre fusion protein inserted in the Il17a locus. We will use a double reporter strategy by breeding these animals to Rosa26-YFP NOD mice to indelibly mark cells with a history of IL-17A production. These mice will provide a novel tool to unequivocally study the contributions of Th17 cells to T1D and the potential functional interrelationships between Th1 and Th17 cells that lead to diabetes onset. The ability to identify changes in the development of Th17 cells and their functions will facilitate the design of appropriate strategies to control autoaggressive CD4 cells and provide new insights into the biology of Th17 cells.