Regulation of Gastric Epithelial Cells in the Mouse

描述（由申请人提供）：这是一项A2申请，使用基因工程小鼠来评估自身免疫性胃炎（AIG）发展中涉及的壁细胞功能调节和机制。分析的重点是在上一个资助期开发的Ctox7转基因小鼠模型。Ctox转基因提高了酸分泌，导致壁细胞cAMP增加。随着小鼠年龄的增长，它们会患上萎缩性胃炎，这与抗壁细胞抗体的产生有关。自体免疫的自发发展定义了一种新的AIG实验模型，是本应用的重点。我们验证了以下最重要的假设：慢性高cAMP导致的壁细胞过度刺激导致炎症，从而导致AIG的发展和壁细胞的破坏，最终导致胃粘膜转化。三个具体目标针对拟议机制的不同方面。目的1将着重于cAMP过度刺激在壁细胞功能和死亡方面的意义。我们的初步结果显示腺体间室TUNEL染色增加，提示萎缩的凋亡机制。我们将测试壁细胞cAMP增加是否使壁细胞对细胞因子诱导的细胞死亡敏感。我们还将研究由cAMP增加引起的形态学和基因表达的变化，以进一步了解这一关键的壁细胞信号调节因子的重要性。目的2将关注炎症反应，并验证AIG与依赖于细胞因子干扰素-7 （IFN-y）的Th1免疫反应相关的假设。细胞浸润将通过FACS分析表征，并分析胃和脾细胞的细胞因子产生。初步数据显示，转基因Ctox7增加了IFN-y的表达。在IFN-y缺乏的背景下分析Ctox7转基因将测试细胞因子依赖性。Aim 3将检验AIG的菌株依赖性，以及环境病原菌诱导的炎症是否能促进AIG的发展。C57BL/6株自身免疫的自发发展是Ctox7自身免疫性胃炎模型所特有的。我们还将在Balb/c背景下测试Ctox7，这是AIG其他模型的允许应变背景。本目的还将通过对幽门螺杆菌感染和无菌小鼠的分析来检验环境病原体的重要性。这些实验将比较Ctox7模型与先前表征的小鼠胸腺切除AIG模型。慢性萎缩性胃炎和AIG导致的恶性贫血是严重的人类健康问题。本项目将使用一种新的实验性小鼠AIG模型来研究导致胃自身免疫性疾病发展的机制。这些研究将进一步了解壁细胞刺激和幽门螺杆菌感染在胃炎症发生中的意义，而胃炎症与胃癌的发生有关。

DESCRIPTION (provided by applicant): This is an A2 application that uses genetically engineered mice to evaluate the regulation of parietal cell function and mechanisms involved in the development of autoimmune gastritis (AIG). The analysis is focused on the Ctox7 transgenic mouse model, which was developed in the previous funding period. Ctox transgenics have enhanced acid secretion resulting from increased parietal cell cAMP. As the mice age they develop atrophic gastritis associated with the production of anti-parietal cell antibodies. The spontaneous development of autoimmunity defines a new experimental model for AIG, which is the focus of this application. We test the following overriding hypothesis: Hyperstimulation of the parietal cell due to chronic high cAMP leads to inflammation, which results in the development of AIG and the destruction of parietal cells and eventual gastric mucosal transformation. Three specific aims are directed to different aspects of the proposed mechanism. Aim 1 will focus on the significance of the cAMP hyperstimulation in regard to parietal cell function and death. Our preliminary results show increased TUNEL staining in the glandular compartment suggesting an apoptotic mechanism for the atrophy. We will test whether increased parietal cell cAMP predisposes the parietal cell to sensitivity to cytokine-induced cell death. We will also examine changes in morphology and gene expression resulting from increased cAMP to further understand the significance of this critical parietal cell signaling regulator. Aim 2 will focus on the inflammatory response and test the hypothesis that AIG is associated with a Th1 immune response dependent on the cytokine interferon-7 (IFN-y). Cellular infiltrates will be characterized by FACS analysis and cytokine production in stomach and spenocytes will be analyzed. Preliminary data shows Ctox7 transgenics have increased IFN-y expression. Analyzing Ctox7 transgenics on an IFN-y deficient background will test cytokine dependency. Aim 3 will test the strain-dependency of AIG and whether inflammation induced by environmental pathogens can enhance the development of AIG. Spontaneous development of autoimmunity in a C57BL/6 strain is unique to the Ctox7 model of autoimmune gastritis. We will also test Ctox7 on a Balb/c background, which is the permissive strain background for other models of AIG. This aim will also examine the importance of environmental pathogens by analysis of Helicobacter infected and germ-free mice. These experiments will compare the Ctox7 model to the previously characterized mouse thymectomy model of AIG. Chronic atrophic gastritis, and AIG leading to pernicious anemia are significant human health concerns. This project will use a new experimental mouse model of AIG to examine mechanisms leading to the development of autoimmune disease in the stomach. These studies will further our understanding of the significance of parietal cell stimulation and Helicobacter infection on the development of gastric inflammation, which is associated with the development of stomach cancer.