Regulation of differentiation in esophageal epithelia

食管上皮分化的调节

• 批准号: 8011268
• 负责人: JONATHAN P KATZ
• 金额: $ 6.4万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-01-20 至 2010-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8011268
• 关键词: Ablation; Acids; Adult; Biochemical; Cell Proliferation; Cell physiology; Cells; Colon; Development; Ectopic Expression; Embryo; Epithelial; Epithelial Cells; Epithelium; Equilibrium; Esophageal; Esophageal mucous membrane; Esophagus; Excision; GKLF protein; Gastroenterology; Gastrointestinal tract structure; Genes; Genetic; Growth; Histology; Homeostasis; Human; Infection; Injury; Intraepithelial Neoplasia; Keratin; Keratin-19; Link; Malignant - descriptor; Malignant Neoplasms; Mediating; Messenger RNA; Molecular; Mus; Nature; Pancreas; Platelet Factor 4; Play; Polyps; Process; Reflux; Regulation; Research Personnel; Retroviridae; Role; Skin; Small Interfering RNA; Stomach; Testing; Tissues; Viral Genes; cellular transduction; design; in vivo; insight; null mutation; overexpression; postnatal; programs; promoter; transcription factor

Klf4 (KruppeMike factor 4, previously known as GKLF) is an epithelial zinc-finger protein which controls cellular proliferation and differentiation in the skin and gastrointestinal tract. Klf4 mRNA is found at high evels in growth-arrested cells and is nearly undetectable in dividing cells. Klf4 is normally found only in regions of differentiating epithelial cells, including in the esophagus, and expression is downregulated in epithelial dysplasia, including polyps and cancer. Mice homozygous for a null mutation in Klf4 die on postnatal day 1 and show abnormal differentiation of the skin and colon (Katz et al, Development, 2002). Using tissue-specific gene ablation in mice, we have also demonstrated that Klf4 plays a vital role in adult gastric epithelial proliferation and differentiation (Katz et al, Gastroenterology, 2005). As Klf4 regulates a number of genes known to be important in esophageal proliferation and differentiation, including keratin 4, ED-L2, and keratin 19, Klf4 undoubtedly plays a critical role in the esophagus as well. Notably, keratin 19 is nvolved in malignant transformation in both the esophagus and pancreas. Nonetheless, the function of Klf4 in esophageal epithelial cells has not been investigated. In these studies, we will examine the role of Klf4 in the esophagus by testing the following hypotheses: (1) Loss of K!f4 in esophageal epithelia results in increased cell proliferation and/or altered differentiation, and (2) Klf4 overexpression in esophageal epithelial cells alters cellular differentiation and/or proliferation. The following interrelated Specific Aims will test these hypotheses using genetic and biochemical approaches: (1) To analyze the function of Klf4 in esophageal epithelial homeostasis (a) through studies of histology, cell proliferation, and differentiation in adult mice lacking Klf4 in the esophageal mucosa and (b) by analyzing the effects of Klf4 deletion in primary esophageal cells; and (2) To study the effect of Klf4 overexpression in esophageal epithelia by (a) overexpressing Klf4 in mice using the esophageal-specific EBV ED-L2 promoter and (b) by analyzing the effects of increased Klf4 expression in primary esophageal cells. Taken together, these mechanistically oriented and complementary studies will provide new insights into normal esophageal epithelial homeostasis and establish paradigms for how the proliferation-differentiation equilibrium may be subverted during mucosal injury and transformation.

Klf4（KruppeMike 因子 4，以前称为 GKLF）是一种上皮锌指蛋白，它控制 皮肤和胃肠道中的细胞增殖和分化。 Klf4 mRNA 被发现处于高水平 在生长停滞的细胞中增加，在分裂的细胞中几乎检测不到。 Klf4 通常只存在于 分化上皮细胞的区域，包括食道，表达下调 上皮发育不良，包括息肉和癌症。 Klf4 无效突变纯合小鼠死亡 出生后第 1 天，显示皮肤和结肠的异常分化（Katz 等人，Development，2002）。 通过对小鼠进行组织特异性基因消融，我们还证明 Klf4 在成年小鼠中发挥着至关重要的作用。 胃上皮增殖和分化（Katz 等人，Gastroenterology，2005）。由于 Klf4 调节 已知对食管增殖和分化很重要的基因数量，包括角蛋白 4， ED-L2 和角蛋白 19、Klf4 无疑在食道中也起着至关重要的作用。值得注意的是，角蛋白 19 参与食道和胰腺的恶性转化。尽管如此，Klf4的功能 尚未在食管上皮细胞中进行研究。在这些研究中，我们将研究 Klf4 在 通过测试以下假设来检测食管：(1) 食管上皮细胞中 K!f4 的丢失导致 细胞增殖增加和/或分化改变，以及 (2) 食管上皮中 Klf4 过度表达 细胞改变细胞分化和/或增殖。以下相互关联的具体目标将进行测试 使用遗传和生化方法提出这些假设：（1）分析 Klf4 在 食管上皮稳态 (a) 通过组织学、细胞增殖和分化的研究 食管粘膜中缺乏 Klf4 的成年小鼠，以及 (b) 通过分析 Klf4 缺失对原代小鼠的影响 食管细胞； (2) 通过 (a) 研究食管上皮中 Klf4 过表达的影响 使用食管特异性 EBV ED-L2 启动子在小鼠中过表达 Klf4，并且 (b) 通过分析 原代食管细胞中 Klf4 表达增加的影响。综合起来，这些机械地 定向和互补的研究将为正常食管上皮稳态提供新的见解 并建立关于如何在增殖分化过程中破坏增殖分化平衡的范例 粘膜损伤和转化。