Molecular Mechanisms of Intestinal Atrophy/Hyperplasia

肠萎缩/增生的分子机制

• 批准号: 7339036
• 负责人: RICHARD A. HODIN
• 金额: $ 34.87万
• 依托单位: MASSACHUSETTS GENERAL HOSPITAL
• 依托单位国家: 美国
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-08-01 至 2011-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7339036
• 关键词: Acetylation; Affect; Alkaline Phosphatase; Antibodies; Atrophic; Award; Binding; Biological Assay; Biological Models; Cell Culture System; Cell physiology; Cells; Chromatin; Chromatin Structure; Clinical; Condition; Cultured Cells; Dietary Fats; Differentiation Antigens; Disease; Dissection; Enterocytes; Epithelial; Epithelial Cells; Failure; Functional disorder; Funding; Gene Activation; Gene Expression; Gene Expression Regulation; Gene Silencing; Gene Targeting; Genes; Genetic Transcription; Histone Code; Histones; Hyperplasia; In Vitro; Individual; Inflammation; Inflammatory; Inflammatory Bowel Diseases; Intestines; Lead; Lipopolysaccharides; Methylation; Microbe; Modification; Molecular; Morbidity - disease rate; Nucleic Acid Regulatory Sequences; Pathologic; Pathway interactions; Patients; Phenotype; Physiological; Physiology; Play; Precipitation; Process; Proteins; Research Design; Research Personnel; Research Proposals; Resistance; Role; Salmonella; Sepsis; Serum; Starvation; Stress; Toxin; Transcriptional Activation; Trauma; Work; absorption; base; chromatin immunoprecipitation; cytokine; deprivation; gastrointestinal epithelium; gene repression; genetic regulatory protein; in vitro Model; in vivo; in vivo Model; mortality; programs; response; therapeutic target; transcription factor

We have identified an important adaptive response that occurs in the mammalian gut in the setting of starvation and disease, silencing of the enterocyte differentiation marker gene, intestinal alkaline phosphatase (IAP). Based upon its functions in regard to dietary fat absorption and cellular resistance to toxins (such as LPS) and microbes, the silencing of IAP expression likely has important physiological consequences for the host. As such, the broad aims of this proposal are to delineate the mechanisms that govern IAP gene regulation. Ultimately, we hope to identify therapeutic targets that could be used in the clinical setting to treat patients in the context of starvation and other gut-related conditions. The three specific aims of this proposal represent complementary and distinct approaches to understanding enterocyte differentiation in both normal and pathologic conditions. Aim#1 is based upon our observation that ectopically expressed IAP leads to a remarkable change in enterocyte phenotype, characterized by resistance to LPS and Salmonella. Accordingly, we will examine three transcription factor pathways that activate IAP expression (KLF4, Cdx1, and ZBP-89). Each of these factors will be expressed within intestinal epithelial cells in vitro in order to determine whether they result in altered host cell function in regard to LPS and Salmonella. In Aim #2 we will dissect a single transcriptional pathway using a well-established inducible cell culture system. Chromatin Immuno-precipitation (ChIP) will be used to define the precise changes in chromatin structure that occur when an individual transcription factor (KLF4) binds and activates a specific target gene (IAP). We will examine the secondary modifications that occur in the histone proteins in response to KLF4 binding, the role of associated proteins, and also determine those changes that occur as the IAP gene is turned off. In Aim #3 we will focus on the enterocyte adaptation that occurs in response to diseases and stress. We will use both in vitro and in vivo model systems to examine the molecular mechanisms that govern IAP gene repression in the contexts of starvation and inflammation. Taken together, these studies will have important implications for our understanding of normal intestinal physiology, as well as the gut response to disease states.

我们已经确定了发生在哺乳动物肠道中的一种重要的适应性反应 饥饿和疾病的背景，肠道细胞分化标志基因的沉默 碱性磷酸酶(IAP)。基于它在饮食脂肪吸收和营养方面的功能 细胞对毒素(如内毒素)和微生物的抗性，IAP表达的沉默可能 对寄主有重要的生理后果。因此，这一行动的广泛目标 提案的目的是描述管理IAP基因调控的机制。最终，我们 希望确定可用于临床环境中的治疗靶点 患者在饥饿和其他肠道相关疾病的背景下。 这项提案的三个具体目标代表了相辅相成和截然不同的方法，以 了解正常和病理条件下的肠道细胞分化。目标#1的基础是 根据我们的观察，异位表达IAP导致肠细胞发生显著变化 表型，以对内毒素和沙门氏菌耐药为特征。因此，我们将审查 激活IAP表达的三条转录因子途径(KLF4、CDX1和ZBP-89)。每个人 将这些因子在体外培养的肠上皮细胞中表达，以确定 它们是否会导致宿主细胞在内毒素和沙门氏菌方面的功能改变。在目标2中，我们将 使用成熟的可诱导细胞培养系统剖析单个转录途径。 染色质免疫沉淀(CHIP)将被用来定义染色质的精确变化 当单个转录因子(KLF4)结合并激活特定的 靶基因(IAP)。我们将检验组蛋白中发生的二次修饰 作为对KLF4结合的反应，相关蛋白的作用，也决定了这些变化 在IAP基因关闭时发生。在目标3中，我们将重点介绍肠道细胞的适应 发生于对疾病和压力的反应。我们将使用体外和体内模型系统来 研究在饥饿环境中控制IAP基因抑制的分子机制 和炎症。 综上所述，这些研究将对我们理解常态具有重要意义 肠道生理学，以及肠道对疾病状态的反应。