Inhibition of Microflora-Induced Colitis by NF-kB

描述（由申请人提供）：本提案的目的是确定NF-κ B亚基p50和p65抑制下肠道内炎症的细胞和分子机制。p50的抑制功能可能与结肠内炎症的控制特别相关，因为我们的实验室已经表明，缺乏p50（p50-/-）的小鼠对肝螺杆菌诱导的结肠炎敏感，并且这种敏感性在缺乏p50且p65杂合（p50-/-p65+/-）的小鼠中显著加剧。这些小鼠通过先天免疫系统固有的缺陷对结肠炎的发展敏感。这一缺陷可能反映了控制H的能力不足。在抗原呈递细胞（APC）内，H.与WT巨噬细胞相比，肝细胞感染在p50-/-和p50-/-p65+/-巨噬细胞中诱导更高水平的关键炎性细胞因子IL-12 p40和IP-10。本研究的目的是：1）确定先天免疫系统细胞内p50和p65抑制H.肝使用我们实验室中创建的新型小鼠品系（p50-/-p65+/-RAG-2-/-），我们将评估先天免疫系统中需要p50/p65活性以促进调节性T细胞的抑制功能的可能性。2)探讨p50和p65抑制H.肝细胞炎性基因表达。我们将使用分子技术比较WT、p50-/-和p50-/-p65+/-巨噬细胞中内源性IL-12 p40和IP-10启动子的功能。3)为了确定p50和p65是否防止过度攻击性的免疫反应，伤害宿主，或者，p50和p65是否防止免疫缺陷，导致增加细菌负荷。我们将比较RAG-2-/-和p50-/-p65+/-RAG-2-/-小鼠中的细菌负荷，并确定将功能性先天免疫细胞引入p50-/-p65+/-RAG-2-/-小鼠中是否可以预防H.肝脏引起的炎症。综上所述，我们相信这些研究将导致对炎症性肠病分子发病机制的深入了解，从而可能导致新的治疗策略。

DESCRIPTION (provided by applicant): The purpose of this proposal is to define the cellular and molecular mechanisms by which the NF-kappaB subunits p50 and p65 inhibit inflammation within the lower bowel. The inhibitory functions of p50 may be especially relevant to the control of inflammation within the colon, as our laboratory has shown that mice lacking p50 (p50-/-) are sensitive to colitis induced by Helicobacter hepaticus, and this sensitivity is significantly exacerbated in mice that both lack p50 and are heterozygous for p65 (p50-/-p65+/-). These mice are sensitized to the development of colitis by a defect intrinsic to the innate immune system. This defect may reflect an inability to control H. hepaticus-induced inflammatory gene expression within antigen presenting cells (APCs), as H. hepaticus infection induces higher levels of the critical inflammatory cytokines IL-12p40 and IP-10 in p50-/- and p50-/-p65+/- macrophages than in WT macrophages. The goals of this proposal are: 1) To determine the mechanism by which p50 and p65 within cells of the innate immune system contribute to inhibiting the inflammatory response to H. hepaticus. Using a novel mouse strain created in our laboratory (p50-/-p65+/-RAG-2-/-), we will evaluate the possibility that p50/p65 activity is required within the innate immune system to facilitate the inhibitory function of regulatory T cells. 2) To determine the mechanisms by which p50 and p65 inhibit H. hepaticus induced inflammatory gene expression. We will use molecular techniques to compare the function of endogenous IL-12p40 and IP-10 promoters in WT, p50-/-, and p50-/-p65+/- macrophages. 3) To determine whether p50 and p65 prevent an overaggressive immune response that injures the host, or alternatively, whether p50 and p65 prevent an immune deficiency that leads to increased bacterial burden. We will compare bacterial burden in RAG-2-/- and p50-/-p65+/-RAG-2-/- mice, and determine whether introduction of functional innate immune cells into p50-/-p65+/-RAG-2-/- mice can prevent H. hepaticus-induced inflammation. Taken together, we believe that these studies will lead to insights regarding the molecular pathogenesis of inflammatory bowel disease that could lead to novel therapeutic strategies.