MOLECULAR MECHANISMS OF INTESTINAL ATROPHY/HYPERPLASIA

肠萎缩/增生的分子机制

• 批准号: 7114076
• 负责人: RICHARD A. HODIN
• 金额: $ 8.23万
• 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 2006-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7114076
• 关键词: alkaline phosphatase; atrophy; cell differentiation; cell growth regulation; gastrointestinal epithelium; gene expression; genetic regulatory element; hyperplasia; intestinal villi; laboratory mouse; molecular pathology; tissue /cell culture

EXCEED THE SPACE PROVIDED. We have identified a previously unrecognized 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). Since IAP functions to inhibit fat absorption, its altered levels will lead to either an increase or decrease in body weight, and its silencing under starved/diseased conditions likely represents an important survival mechanism for the organism. As such, the broad aims of this proposal are to delineate the molecular mechanisms that govern IAP gene regulation in order to identify therapeutic targets that could be used in the clinical setting to treat patients in the context of starvation and various disease-states, including morbid obesity. The three specific aims of this proposal represent complementary and distinct approaches to understanding the molecular mechanisms governing enterocyte differentiation in both normal and pathologic conditions. In Aim #1 we will delineate the multiple transcription factor pathways that regulate the IAP gene, focusing on a subset of transcription factors (KLF4, Cdx1/2, ZBP-89, and Sp1/Sp3) that have already been identified as regulators of gut epithelial differentiation. Each of these factors will be examined using functional and biochemical assays in order to define their role in IAP gene regulation. In Aim #2 we will dissect a single transcriptional pathway using a well-established inducible cell culture system. Chromatin Immunoprecipitation 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 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, the gut response to disease states, as well as colonic carcinogenesis. PERFORMANCE SITE ========================================Section End===========================================

超出所提供的空间。 我们已经确定了一个以前未被认识到的适应性反应，发生在哺乳动物肠道中的设置饥饿和疾病，沉默的肠上皮细胞分化标记基因，肠碱性磷酸酶（IAP）。由于IAP的功能是抑制脂肪吸收，其水平的改变将导致体重的增加或减少，并且其在饥饿/疾病条件下的沉默可能代表生物体的重要生存机制。因此，该提案的广泛目标是描述控制IAP基因调控的分子机制，以确定可用于临床环境的治疗靶点，以治疗饥饿和各种疾病状态（包括病态肥胖）的患者。这三个具体目标的建议代表互补和不同的方法来理解在正常和病理条件下肠上皮细胞分化的分子机制。在目标#1中，我们将描述调节IAP基因的多个转录因子途径，重点关注已经被确定为肠道上皮分化调节因子的转录因子子集（KLF 4，Cdx 1/2，ZBP-89和Sp1/Sp3）。这些因素中的每一个都将使用功能和生化测定进行检查，以确定它们在IAP基因调控中的作用。在目标#2中，我们将使用完善的诱导型细胞培养系统剖析单个转录途径。染色质免疫沉淀将用于确定当单个转录因子（KLF 4）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。我们将研究组蛋白中发生的二级修饰，以响应KLF 4结合，并确定IAP基因关闭时发生的变化。在目标3中，我们将重点关注肠上皮细胞对疾病和压力的适应。我们将使用体外和体内模型系统来研究在饥饿和炎症的背景下控制IAP基因抑制的分子机制。总之，这些研究将对我们理解正常肠道生理学、肠道对疾病状态的反应以及结肠癌发生具有重要意义。性能现场=