APC and Retinoids in Zebrafish Enterocyte Development

斑马鱼肠细胞发育中的 APC 和类维生素A

• 批准号: 7613412
• 负责人: DAVID A JONES
• 金额: $ 25.2万
• 依托单位: UNIVERSITY OF UTAH
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-08-01 至 2010-08-04
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7613412
• 关键词: Anabolism; Biological Models; Carcinoma; Cells; Clinical; Colonic Adenoma; Colonic Neoplasms; Data; Defect; Development; Differentiation Antigens; Embryo; Enterocytes; Enzymes; Epithelial Cells; Fishes; Foundations; Genes; Genetic; Genetic screening method; Goals; Human; Intestines; Measures; Modeling; Mutation; Pathway interactions; Phenotype; Play; Preventive; Principal Investigator; Production; Publishing; Retinoids; Retinol dehydrogenase; Role; Signal Transduction; Structure; Testing; Time; Tretinoin; Tumor Suppressor Proteins; Zebrafish; beta catenin; colon cancer cell line; intestinal epithelium; intestinal fatty acid binding protein; knock-down; novel; prevent; programs

DESCRIPTION (provided by applicant): Mutations in APC, or in its regulatory target, beta-catenin, are thought to cause colon neoplasms by promoting proliferation and preventing proper differentiation of colonocytes. However, our understanding of the mechanisms that control colonocyte differentiation is limited. Recent studies have shown that human colon adenomas and carcinomas show a profound deficiency of retinoic acid biosynthetic enzymes. Furthermore, re-introduction of wild type APC into an APC-deficient colon cancer cell line induced retinol dehydrogenase L and increased retinoic acid production. These observations suggest a novel model wherein APC promotes enterocyte differentiation by controlling retinoic acid biosynthesis. The studies outlined in this proposal will examine the genetic relationship between APC and retinoic acid biosynthesis in normal enterocytes using zebrafish as a model system. Preliminary data show that morpholino knockdown of either zAPC or zRDHB in zebrafish embryos results in defects in structures known to require retinoic acid, consistent with a role for these genes in RA-dependent pathways. In addition, APC or zRDHB morphant fish develop intestines that lack columnar epithelial cells and fail to express the differentiation marker intestinal fatty acid binding protein (i-FABP). Treatment of either APC or zRDHB morphant embryos with retinoic acid rescued the defective phenotypes, for the first time placing zAPC upstream of RA and implicating RA in intestinal differentiation. These preliminary data, therefore, strongly support a critical role for retinoic acid in zebrafish enterocyte development and provide genetic evidence placing retinoic acid and hox genes downstream of APC. The long term goal of this project is to facilitate the development of new preventive measures for colon adenoma formation by understanding the earliest cellular perturbations that follow APC mutation.

描述（由申请人提供）：APC或其调节靶点β-连环蛋白的突变被认为通过促进增殖和阻止结肠细胞的正常分化而引起结肠肿瘤。然而，我们对控制结肠细胞分化的机制的理解是有限的。最近的研究表明，人类结肠腺瘤和结肠癌严重缺乏视黄酸生物合成酶。此外，将野生型APC重新引入APC缺陷的结肠癌细胞系中可诱导视黄醇脱氢酶L并增加视黄酸的产生。这些观察结果提出了一种新模型，其中 APC 通过控制视黄酸生物合成来促进肠上皮细胞分化。该提案中概述的研究将使用斑马鱼作为模型系统来检查正常肠上皮细胞中 APC 和视黄酸生物合成之间的遗传关系。初步数据表明，斑马鱼胚胎中 zAPC 或 zRDHB 的吗啡啉敲低会导致已知需要视黄酸的结构缺陷，这与这些基因在 RA 依赖性途径中的作用一致。此外，APC或zRDHB变形鱼发育的肠道缺乏柱状上皮细胞，并且无法表达分化标记物肠脂肪酸结合蛋白（i-FABP）。用视黄酸处理 APC 或 zRDHB 变形胚胎挽救了缺陷表型，首次将 zAPC 置于 RA 上游，并暗示 RA 参与肠道分化。因此，这些初步数据有力地支持了视黄酸在斑马鱼肠细胞发育中的关键作用，并提供了将视黄酸和 hox 基因置于 APC 下游的遗传证据。该项目的长期目标是通过了解 APC 突变后最早的细胞扰动，促进结肠腺瘤形成的新预防措施的开发。