Regulation of IDDM by AIM and Th1-cytokines

描述(申请人提供)：胰岛素依赖型糖尿病(IDDM)的特征是T淋巴细胞渗透到胰腺朗格汉斯的胰岛(胰岛素炎)，继而选择性地破坏分泌胰岛素的β细胞，导致明显的糖尿病。我们初步观察到IDDM与AIM因子(一种我们最初确定为凋亡抑制因子的分泌分子)之间的重要关联是：(1)AIM-/-小鼠回交到非肥胖糖尿病(NOD)背景显示完全预防IDDM；(2)AIM从疾病早期就通过胰岛中的巨噬细胞浸润表达；(3)AIM强烈诱导巨噬细胞和树突状细胞(DC)中的TNF-α、IL-1β、IL-6和IL-12。基于这些发现，出现了一种假说，即AIM可能通过在IDDM发病时诱导最初渗透到胰岛的巨噬细胞和DC中的促炎和I型细胞因子来加速IDDM。具体的目标1和2集中于通过建立在胰岛过度生产AIM的转基因NOD小鼠，预期疾病加速(Aim 1)，通过Tet诱导转基因系统在幼年NOD小鼠的巨噬细胞或DC中诱导它们来测试AIM下游的细胞因子对疾病加速的影响(Aim 2-1)，以及评估在AIM-/-背景的NOD小鼠中细胞因子的表达是否可以恢复AIM-/-背景的NOD小鼠的疾病(Aim 2-2)。此外，我们最近的研究结果表明，AIM可能是Toli/IL-1受体家族中的一员。在特定的目标3中，我们将通过表达筛选巨噬细胞产生的cDNA文库来纯化和鉴定AIM受体。我们还计划通过破坏NOD来源的ES细胞中的基因来创建AIM受体的敲除小鼠，因为我们使用这些细胞产生了AIM-/-。我们提出的研究将阐明IDDM在AIM背景下的确切发病机制，特别是在疾病的早期阶段，因此将有助于通过抑制AIM来开发新的治疗方法。此外，对AIM受体的鉴定将有助于揭示AIM功能的精确分子机制，以及Toll家族生理功能的新方面。

DESCRIPTION (provided by applicant): Insulin-dependent diabetes mellitus (IDDM) is characterized by the infiltration of T-lymphocytes into the islets of Langerhans of the pancreas (insulitis), followed by selective destruction of insulin-secreting beta-cells leading to overt diabetes. Preliminarily, we observed the important associations of IDDM with AIM factor (a secretion molecule we initially identified as an apoptosis inhibitory factor), which are: (1) AIM-/- mice backcrossed to non-obese diabetes (NOD) background showed complete prevention of IDDM; (2) AIM is expressed by infiltrating macrophages in the pancreatic islets from the very early stage of the disease; (3) AIM strongly induces TNF-alpha, IL-1beta, IL-6 and IL-12 in macrophages and dendritic cells (DCs). Based on these findings, a hypothesis has emerged that AIM may accelerate IDDM by inducing pro-inflammatory and type I cytokines in initially infiltrating macrophages and DCs in the islets at the onset of the disease. Specific Aims 1 and 2 are focused on establishing the propriety of the hypothesis by generating transgenic NOD mice that overproduce AIM in the islets, expecting disease acceleration (aim 1), testing the impact of the cytokines downstream of AIM on the disease acceleration by inducing them in macrophages or DCs in young NOD mice via the Tet-inducible transgenic system (aim 2-1), and assessing whether the expression of the cytokines in the absence of AIM may restore the disease in NOD mice on AIM-/- background (aim 2-2). In addition, our recent result that AIM mediates Toll-signaling to induce the cytokines provoked an idea that the putative AIM receptor may be a TolI/IL-1 receptor family member. In Specific Aim 3, we will purify and characterize the AIM receptor by expression screening of a cDNA library generated from macrophage cells. We also plan to create knockout mice of the AIM receptor by disrupting the gene in the NOD-derived ES cells, as we generated AIM-/- by using the cells. Our proposed studies will clarify the precise picture of IDDM pathogenesis in the context of AIM, in particular, during the early stage of the disease, and thus will contribute to development of a new therapy via suppression of AIM. In addition, identification of the AIM receptor will shed light on the precise molecular machinery of AIM functions, as well as a new aspect of physiological function of the Toll-family.