Molecular Mechanisms Regulating Intestinal Homeostasis

调节肠道稳态的分子机制

• 批准号: 8434533
• 负责人: Vincent W Yang
• 金额: $ 34.15万
• 依托单位: STATE UNIVERSITY NEW YORK STONY BROOK
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-09-11 至 2017-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8434533
• 关键词: Apical; Architecture; Biological Assay; Cell Culture System; Cell Death; Cell Differentiation process; Cell Line; Cell physiology; Colitis; Colon; Complex; DNA Binding; Data; Defect; Development; Disease; E-Cadherin; Ectopic Expression; Enterocolitis; Epidermal Growth Factor Receptor; Epithelial; Epithelial Cells; Event; Exhibits; Family; Flare; Genetic; Goals; Healed; Homeostasis; Hyperplasia; In Vitro; Inflammatory Bowel Diseases; Injury; Intercellular Junctions; Intestinal Mucosa; Intestines; Knockout Mice; Luciferases; Maintenance; Mediating; Methods; Modeling; Molecular; Mucous Membrane; Mus; Natural regeneration; Outcome; Patients; Permeability; Process; Regulation; Reporter; Reporting; Role; Small Interfering RNA; Sodium Dextran Sulfate; Structure; Testing; Tissues; Transcriptional Activation; Transgenic Organisms; Ulcer; Wound Healing; base; cell motility; crypt cell; gain of function; healing; improved; in vivo; injured; injury and repair; intestinal crypt; intestinal epithelium; loss of function; member; migration; mouse model; nanoparticle; novel; premature; promoter; repaired; research study; spatiotemporal; stem cell division; therapeutic target; transcription factor

DESCRIPTION (provided by applicant): The intestinal mucosa maintains its integrity through spatiotemporal regulation of proliferation, differentiation, migration, and cell death along the crypt-luminal axis of the intestine. The molecular mechanisms that coordinate these events, particularly in the context of injury repair, are not well understood. Furthermore, it is not known how perturbations of these processes impact cell junction formation and barrier function. Kruppel- like factor 5 (KLF5) is a member of a family of transcription factors that function in the regulation of diverse cellular processes including development, proliferation, and differentiation. KLF5 is highly expressed in the proliferative component of the intestinal epithelium, and has been shown to promote proliferation of intestinal epithelial cells in vitro and in vivo. Recent dat from mice with intestine-specific deletion of Klf5 indicate that KLF5 is required for maintenance of intestinal crypt architecture and epithelial barrier integrity. In addition, it was shown recenty that KLF5 is necessary for mucosal healing in the dextran sulfate sodium (DSS) mouse model of colitis. Based on these results, we hypothesize that KLF5 controls renewal and maturation of epithelial cells along the crypt-luminal axis and is required for intestinal epithelial integrity. he following aims have been developed to test this hypothesis: (I) Define the role of KLF5 in regulating proliferation, migration, and maturation of epithelial cells along the crypt-luminal axi of the intestine. Genetic mouse models and cell culture systems will be used for ectopic expression or inhibition of KLF5 to explore the role of KLF5 in regulating processes involved in intestinal epithelial homeostasis. (II) Determine the requirement of KLF5 in maintaining intestinal epithelial barrier function. The effects of KLF5 expression on intestinal permeability and the formation of apical junctional complexes will be determined. (III) Examine the role of KLF5 in intestinal epithelial wound repair. These experiments will test whether increased levels of KLF5 can improve outcome and epithelial healing in DSS-induced colitis. Several methods to increase KLF5 expression in the mouse colon will be tested, including adenoviral delivery, nanoparticle delivery and transgenic expression. Reciprocal studies using mice with inducible intestine-specific deletion of Klf5 will also be conducted to test whether KLF5 is necessary for repair of intestinal injury. The long-term goal of these studies is to elucidate the molecular mechanisms that regulate intestinal epithelial integrity, both in situations of tissue renewal and injury repar. The proposed studies will contribute to a better understanding of factors that coordinate the processes of proliferation, migration, and differentiation to maintain intestinal architecture and barrier function. In particular, these studies will explore novel roles for KLF5 in the processes o epithelial maturation, migration, and cell junction formation, and the possibility for KLF5 as a therapeutic target in disease conditions such as inflammatory bowel disease. PUBLIC HEALTH RELEVANCE: One of the major complications and possibly causes of inflammatory bowel disease (IBD) is disruption of the barrier function of the intestinal epithelium which exacerbates and prolongs active flare-ups. Understanding how the injured mucosa is repaired and identifying key molecules involved in the maintenance and repair of the epithelial barrier function can provide potential therapeutic targets directed at mucosal healing in IBD patients.

描述（由申请人提供）：肠粘膜通过沿肠隐窝-腔轴的增殖、分化、迁移和细胞死亡的时空调节来保持其完整性。协调这些事件的分子机制，特别是在损伤修复的背景下，尚不清楚。此外，尚不清楚 这些过程的扰动如何影响细胞连接的形成和屏障功能。 Kruppel 样因子 5 (KLF5) 是转录因子家族的成员，在 调节不同的细胞过程，包括发育、增殖和分化。 KLF5在肠上皮的增殖成分中高表达，并且在体外和体内已被证明可以促进肠上皮细胞的增殖。最近来自肠道特异性缺失 Klf5 的小鼠的数据表明，KLF5 是维持肠隐窝结构和上皮屏障完整性所必需的。此外，最近的研究表明，在右旋糖酐硫酸钠 (DSS) 小鼠结肠炎模型中，KLF5 对于粘膜愈合是必需的。基于这些结果，我们假设 KLF5 控制沿隐窝管腔轴的上皮细胞的更新和成熟，并且是肠上皮完整性所必需的。为了检验这一假设，我们制定了以下目标： (I) 定义 KLF5 在调节肠隐窝管腔轴上皮细胞的增殖、迁移和成熟中的作用。遗传小鼠模型和细胞培养系统将用于KLF5的异位表达或抑制，以探索KLF5在肠上皮稳态调节过程中的作用。 (二)确定KLF5维持肠道的需要量 上皮屏障功能。将确定 KLF5 表达对肠道通透性和顶端连接复合物形成的影响。 (III)考察KLF5在肠上皮伤口修复中的作用。这些实验将测试 KLF5 水平的增加是否可以改善 DSS 诱导的结肠炎的结果和上皮愈合。将测试几种增加小鼠结肠中 KLF5 表达的方法，包括腺病毒递送、纳米颗粒递送和转基因表达。还将使用具有可诱导肠道特异性缺失 Klf5 的小鼠进行相互研究，以测试 KLF5 是否是修复肠道损伤所必需的。这些研究的长期目标是阐明在组织更新和损伤修复情况下调节肠上皮完整性的分子机制。拟议的研究将有助于更好地了解协调增殖、迁移和分化过程以维持肠道结构和屏障功能的因素。特别是，这些研究将探索 KLF5 在上皮成熟、迁移和细胞连接形成过程中的新作用，以及 KLF5 作为炎症性肠病等疾病治疗靶点的可能性。 公共卫生相关性：炎症性肠病 (IBD) 的主要并发症和可能原因之一是肠上皮屏障功能的破坏，从而加剧并延长活动性发作。了解受损粘膜如何修复并识别参与上皮屏障功能维持和修复的关键分子可以为 IBD 患者粘膜愈合提供潜在的治疗靶点。