Mouse models for esophageal Cox-2 oxidative stress and DNA damage

食管 Cox-2 氧化应激和 DNA 损伤的小鼠模型

• 批准号: 8680384
• 负责人: JOHN P. LYNCH
• 金额: $ 14.73万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-06-13 至 2018-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8680384
• 关键词: Achievement; Acids; Adoption; Advisory Committees; Anabolism; Animal Model; Antioxidants; Area; Award; Barrett Esophagus; Base Excision Repairs; Bile Reflux; Biomedical Research; Cell Culture System; Cell Lineage; Cells; Cellular Morphology; Characteristics; Chronic; Clinical; Columnar Epithelium; Cyst; DNA Adducts; DNA Damage; DNA Repair; Data; Development; Dysplasia; Educational Curriculum; Eicosanoids; Enzymes; Epithelial Cells; Epithelium; Esophageal; Esophageal Adenocarcinoma; Esophageal injury; Esophageal mucous membrane; Esophagitis; Esophagus; Experimental Animal Model; Gastric Acid; Gastroesophageal reflux disease; Gene Expression; Genes; Goals; Health; Human; Hydrogen Peroxide; In Vitro; Incidence; Inflammation; Inflammatory; Inflammatory Response; Injury; Intestines; Knowledge; Lipid Peroxides; Malignant Neoplasms; Malignant neoplasm of esophagus; Mentors; Metaplasia; Metaplastic Epithelial Cell; Mission; Modeling; Molecular; Mucins; Mus; Oncogenes; Outcome; Oxidative Stress; Pathogenesis; Patient Care; Pennsylvania; Phenotype; Precancerous Conditions; Prevention strategy; Prostaglandin-Endoperoxide Synthase; Prostaglandins; Public Health; Rattus; Reflux; Research; Research Personnel; Resources; Risk Factors; Role; Testing; Tissues; Training; Transgenic Mice; Transgenic Model; Universities; Work; base; cytokine; experience; glutathione peroxidase; human disease; improved; inhibitor/antagonist; innovation; insight; keratinocyte; mouse model; novel; novel therapeutics; overexpression; oxidative DNA damage; oxidative damage; pressure; prevent; programs; public health relevance; response; response to injury; skills; wiki

DESCRIPTION (provided by applicant): Barrett's esophagus (BE) is the replacement of the normal squamous esophageal epithelium with an intestinalized columnar epithelium. It occurs in response to chronic acid and bile reflux and is an important risk factor for the development of esophageal adenocarcinoma (EAC). BE is thought to be an adaptive response to chronic tissue injury and the release of pro-inflammatory prostaglandins and cytokines. However, the mechanisms underpinning BE pathogenesis remain poorly understood in part due to the paucity of experimental animal models. The development of innovative, genetically based and physiologically relevant mouse models for BE is an important long-term objective of my lab. Cox-1 and Cox-2 are the rate-limiting enzymes in prostaglandin biosynthesis. Cox-2 expression is induced in the esophagus by acid reflux, and the inhibition of Cox-2 reduces the progression to BE and cancer in a rat bile reflux model. Cox-2 is also known to increase intracellular oxidative stress and damage DNA. Nevertheless, a role for Cox-2 in the pathogenesis of BE and EAC has not been tested. We have utilized a novel 3D in vitro cell culture system to model BE pathogenesis. When we express Cox-2 in normal human esophageal keratinocytes we observe the development of intestinal mucin-filled cysts. This suggests that Cox-2 expression is sufficient to induce an altered cell lineage from keratinocytes, one that has mucin-secretory features consistent with BE cells. We therefore hypothesize that Cox-2 expression in the murine esophagus results in a chronic esophagitis that models GERD esophagitis by provoking oxidative stress, DNA damage, and the development of metaplasia and dysplasia. The rationale for the proposed research is that while a role for Cox-2 in the pathogenesis of Barrett's esophagus is suggested by clinical observational data, this has not been proven in animal models. Once it is established, greater consideration can be given to pharmacological approaches to prevent the onset of BE and limit progression to cancer. Guided by strong preliminary data, this hypothesis will be tested by the following inter-related Specific Aims: 1) Does chronic Cox-2 activity in the esophagus of K14-Cox2 mice result in inflammation, oxidative stress, DNA damage, and the adoption of an altered differentiation program? 2) Can a diminished antioxidant response or defective DNA repair synergize with esophageal Cox-2 expression to accelerate the onset of DNA damage, metaplasia, and dysplasia? Summary BE is an increasingly common precancerous condition and an emerging U.S. health problem. Our studies are significant because they mechanistically explore the contributions of Cox2 to BE pathogenesis, and we anticipate our approaches will yield improved mouse models for BE. Additionally, as a Midcareer Investigator Award, this study will provide an outstanding focus for the PI to: 1) advance his skills in mouse pathobiology research and comprehensive phenotyping; 2) serve as a basis for mentoring of junior investigators in these areas; and 3) Conduct state-of-the-art biomedical research in mouse pathobiology.

描述（由申请方提供）：Barrett食管（BE）是正常鳞状食管上皮被钙化柱状上皮替代。它发生在慢性酸和胆汁反流的反应中，是食管腺癌（EAC）发展的重要危险因素。BE被认为是对慢性组织损伤和促炎性前列腺素和细胞因子释放的适应性反应。然而，BE的发病机制仍然知之甚少，部分原因是缺乏实验动物模型。开发创新的、基于遗传的和生理相关的BE小鼠模型是我实验室的一个重要的长期目标。考克斯-1和考克斯-2是前列腺素生物合成的限速酶。食管中的考克斯-2表达由酸反流诱导，并且在大鼠胆汁反流模型中抑制考克斯-2减少BE和癌症的进展。还已知考克斯-2增加细胞内氧化应激和损伤DNA。然而，考克斯-2在BE和EAC发病机制中的作用尚未得到证实。我们已经利用一种新的三维体外细胞培养系统来模拟BE发病机制。 当我们在正常人食管角化细胞中表达考克斯-2时，我们观察到肠粘蛋白填充的囊肿的发展。这表明考克斯-2表达足以诱导角质形成细胞的细胞谱系改变，其具有与BE细胞一致的粘蛋白分泌特征。因此，我们假设考克斯-2在小鼠食管中的表达导致慢性食管炎，其通过引起氧化应激、DNA损伤以及化生和异型增生的发展来模拟GERD食管炎。拟议研究的基本原理是，虽然临床观察数据表明考克斯-2在巴雷特食管发病机制中的作用，但这尚未在动物模型中得到证实。一旦确定，可以更多地考虑药理学方法来预防BE的发作并限制癌症的进展。在强有力的初步数据的指导下，该假设将通过以下相互关联的特定目的进行检验：1）K14-Cox 2小鼠食管中的慢性考克斯-2活性是否导致炎症、氧化应激、DNA损伤和采用改变的分化程序？2)抗氧化反应减弱或DNA修复缺陷能否与食管考克斯-2表达协同作用，加速DNA损伤、化生和异型增生的发生？ BE是一种越来越常见的癌前病变，也是美国一个新出现的健康问题。我们的研究是重要的，因为它们从机理上探索了Cox 2对BE发病机制的贡献，我们预计我们的方法将产生改进的BE小鼠模型。此外，作为一项中期研究者奖，本研究将为PI提供一个突出的重点：1）提高他在小鼠病理生物学研究和综合表型分析方面的技能; 2）作为指导这些领域初级研究者的基础; 3）在小鼠病理生物学方面进行最先进的生物医学研究。