A20 Mediated Regulation of Colitis and Spondyloarthritis

描述(申请人提供)：最近的研究表明，炎症性肠病(IBD)是由于正常宿主免疫细胞对微生物分子的反应中断造成的，这些微生物分子可以引发肠道炎症。树突状细胞(DC)是一种特殊的免疫细胞，对微生物高度敏感，能有效地激活炎症细胞。由于DC可能经常或强烈地感觉到肠道中存在微生物，它们引起炎症的倾向可能取决于它们的细胞内调节或对遇到微生物的“解释”。因此，调节由微生物触发的信号的细胞内蛋白可能是承诺公开炎症反应的核心。A20是一种酶，可以有效地限制来自微生物传感途径的信号，包括Toll样受体(TLR)、NOD和TNF信号。因此，我们的中心假设是，A20在树突状细胞中的特异性表达维持免疫动态平衡，预防IBD和IBD相关的关节炎。为了验证我们的中心假设，我们培育了一种新的小鼠品系，A20FL/FL CD11c-CRE小鼠，其中A20特定地从DC中删除。值得注意的是，我们对这些小鼠的初步数据表明，这些小鼠自发地发展为结肠炎、血清阴性关节炎和脊柱关节炎，这是人类IBD的典型症状。我们现在建议使用这些A20FL/FL CD11-cre小鼠来确定树突状细胞中A20表达与这些刺激表型之间的联系的细胞和分子机制。具体地说，我们将确定管腔微生物和T细胞是否参与A20缺陷树突状细胞导致结肠炎和关节炎的病理生理学(目标1)。由于A20可以限制树突状细胞内的信号，包括MyD88依赖的TLR信号，我们将使用复合A20FL/FL MyD88FL/FL CD11c-CRE小鼠来确定哪些A20调节的信号是MyD88依赖的，哪些信号是MyD88非依赖的。对这些小鼠的研究将揭示哪些细胞内DC信号和DC产物调节T细胞激活、结肠炎和血清阴性关节炎(目标2)。A20是一种泛素修饰酶，调节信号蛋白的泛素化，也与NFkB-1或ABIN-1的A20结合抑制物结合。为了确定A20和ABIN-1可能协作限制DC中信号的分子机制，我们还培育了DC中特异性缺失ABIN-1的小鼠。我们现在将使用这些小鼠来研究ABIN-1如何与A20合作来限制DC中的信号并预防结肠炎和关节炎(目标3)。

DESCRIPTION (provided by applicant): Recent studies suggest that inflammatory bowel disease (IBD) results from the disruption of normal host immune cells responses to microbial molecules that can trigger inflammation in the intestine. Dendritic cells (DCs) are specialized immune cells that are highly sensitive to microbes and can potently activate inflammatory cells. As DCs may frequently or tonically sense the presence of microbes in the intestine, their propensity to cause inflammation may be dependent on their intracellular regulation or "interpretation" of encounters with microbes. Hence, intracellular proteins that regulate signals triggered by microbes may be central to the commitment to overt inflammatory responses. A20 is an enzyme that potently restricts signals from microbial sensing pathways, including Toll-like receptor (TLR), NOD and TNF signals. Thus, our central hypothesis is that A20 expression specifically in DCs preserves immune homeostasis and prevents IBD and IBD-associated arthritis. To test our central hypothesis, we have generated a novel strain of mice, A20FL/FL CD11c-Cre mice, in which A20 is deleted specifically from DCs. Remarkably; our preliminary data with these mice suggest that these mice spontaneously develop colitis, sero-negative arthritis and spondyloarthritis, a stereotypical syndrome in human IBD. We now propose to use these A20FL/FL CD11-cre mice to determine the cellular and molecular mechanisms linking A20 expression in DCs to these provocative phenotypes. Specifically, we will determine whether luminal microbes and T cells are involved in the pathophysiologies by which A20 deficient DCs cause colitis and arthritis (Aim 1). As A20 may restrict intracellular signals in DCs, including MyD88 dependent TLR signals, we will use compound A20FL/FL MyD88FL/FL CD11c-Cre mice to determine which A20 regulated signals in DCs are MyD88-dependent and which signals are MyD88-independent. Studies with these mice will unveil which intracellular DC signals and DC products regulate T cell activation, colitis, and sero-negative arthritis (Aim 2). A20 is a ubiquitn modifying enzyme that regulates ubiquitination of signaling proteins and also binds to A20 Binding Inhibitor of NFkB-1, or ABIN-1. To define the molecular mechanisms by which A20 and ABIN-1 may collaborate to restrict signals in DCs, we have also generated mice lacking ABIN-1 specifically in DCs. We will now use these mice to study how ABIN-1 collaborates with A20 to restrict signaling in DCs and prevent colitis and arthritis (Aim 3).