Regulation of Gastric Epithelial Cells in the Mouse

描述(申请人提供)：这是一个A2应用程序，使用基因工程小鼠来评估壁细胞功能的调节和涉及自身免疫性胃炎(AIG)发展的机制。分析的重点是Ctox7转基因小鼠模型，该模型是在之前的资助期间开发的。CTOX转基因药物增加了壁细胞cAMP所导致的胃酸分泌。随着年龄的增长，它们会患上萎缩性胃炎，这与抗壁细胞抗体的产生有关。自身免疫的自发发展为AIG定义了一种新的实验模型，这是本应用的重点。我们测试了以下压倒一切的假设：慢性高cAMP对壁细胞的过度刺激会导致炎症，从而导致AIG的发展和壁细胞的破坏，并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将重点放在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，腺室的TUNEL染色增加，提示萎缩是一种细胞凋亡机制。我们将测试增加的壁细胞cAMP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cAMP增加引起的形态和基因表达的变化，以进一步了解这一关键的壁细胞信号调节因子的意义。目的2将重点放在炎症反应上，并验证AIG与依赖细胞因子干扰素-7(IFN-γ)的Th1免疫反应相关的假设。细胞浸润物将通过FACS分析来表征，胃和脾细胞中细胞因子的产生将被分析。初步数据显示，转基因Ctox7增加了干扰素-γ的表达。在干扰素-γ缺乏的背景下分析Ctox7转基因将测试细胞因子的依赖性。目的3将测试AIG的菌株依赖性，以及环境病原体诱导的炎症是否能促进AIG的发展。C57BL/6菌株自身免疫的自发发展是自身免疫性胃炎Ctox7模型所特有的。我们还将在Balb/c背景上测试Ctox7，这是AIG其他型号的允许菌株背景。这一目标还将通过对感染了幽门螺杆菌和没有细菌的小鼠的分析来检查环境病原体的重要性。这些实验将把Ctox7模型与之前描述的AIG小鼠胸腺切除模型进行比较。慢性萎缩性胃炎和AIG导致的恶性贫血是人类健康的重大问题。该项目将使用一种新的实验性AIG小鼠模型来研究导致胃部自身免疫性疾病发展的机制。这些研究将进一步加深我们对壁细胞刺激和幽门螺杆菌感染在胃炎症发展中的意义的理解，而胃炎与胃癌的发生有关。

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.