Molecular Mechanisms of Intestinal Atrophy/Hyperplasia

肠萎缩/增生的分子机制

• 批准号: 7197923
• 负责人: RICHARD A. HODIN
• 金额: $ 35.22万
• 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/7197923
• 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

DESCRIPTION (provided by applicant): 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.

描述（由申请人提供）：我们已经鉴定出在饥饿和疾病、肠上皮细胞分化标记基因肠碱性磷酸酶（IAP）沉默的情况下哺乳动物肠道中发生的重要适应性反应。基于其在膳食脂肪吸收以及细胞对毒素（如 LPS）和微生物的抵抗方面的功能，IAP 表达的沉默可能对宿主产生重要的生理后果。因此，该提案的主要目标是描述 IAP 基因调控的机制。最终，我们希望找到可用于临床环境的治疗靶点，以治疗饥饿和其他肠道相关疾病的患者。该提案的三个具体目标代表了理解正常和病理条件下肠上皮细胞分化的互补且独特的方法。 Aim#1 基于我们的观察，即异位表达的 IAP 会导致肠上皮细胞表型发生显着变化，其特征是对 LPS 和沙门氏菌具有抵抗力。因此，我们将检查激活 IAP 表达的三种转录因子途径（KLF4、Cdx1 和 ZBP-89）。这些因子中的每一种都将在体外肠上皮细胞内表达，以确定它们是否会导致宿主细胞对 LPS 和沙门氏菌的功能发生改变。在目标#2 中，我们将使用完善的诱导细胞培养系统剖析单个转录途径。染色质免疫沉淀 (ChIP) 将用于定义当单个转录因子 (KLF4) 结合并激活特定靶基因 (IAP) 时发生的染色质结构的精确变化。我们将检查组蛋白响应 KLF4 结合而发生的二次修饰、相关蛋白的作用，并确定 IAP 基因关闭时发生的那些变化。在目标#3中，我们将重点关注肠上皮细胞因疾病和压力而发生的适应。我们将使用体外和体内模型系统来研究在饥饿和炎症情况下控制 IAP 基因抑制的分子机制。总而言之，这些研究将对我们理解正常肠道生理学以及肠道对疾病状态的反应产生重要影响。