Generation of Retinoid Signals during Development

发育过程中类视黄醇信号的产生

基本信息

批准号：
8234448
负责人：
GREGG L DUESTER
金额：
$ 39.39万
依托单位：
SANFORD BURNHAM PREBYS MEDICAL DISCOVERY INSTITUTE
依托单位国家：
美国
项目类别：
财政年份：
2002
资助国家：
美国
起止时间：
2002-08-01 至 2015-12-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8234448
关键词：
Aging All-Trans-Retinol Alleles Anterior Antibodies Binding Cell Differentiation process Defect Development Developmental Gene Developmental Process EP300 gene Ectoderm Electrophoretic Mobility Shift Assay Embryo Embryonic Development Ensure Enzymes Equilibrium Ethylnitrosourea Exhibits Fibroblast Growth Factor Gene Expression Gene Targeting Generations Genes Genetic Genetic Models Genetic Transcription Genotype Goals Heat-Shock Response In Vitro Investigation Knowledge LacZ Genes Learning Left Ligands Location Measures Mediating Mesoderm Modeling Mus NRIP1 gene Neuroectoderm Nuclear Nucleotides Nutrient Organ Pathway interactions Phenotype Process Reporter Repression Response Elements Retinaldehyde Retinoic Acid Receptor Retinoic Acid Response Element Retinoids Retinol dehydrogenase Signal Pathway Signal Transduction Signaling Molecule Somites Source Staging Stem cells Time Tissues Transgenes Transgenic Organisms Tretinoin Zebrafish chromatin immunoprecipitation combat design human disease improved in vivo loss of function mouse model mutant prevent progenitor promoter receptor binding regenerative retinaldehyde dehydrogenase somitogenesis

项目摘要

DESCRIPTION (provided by applicant): Great progress has been made identifying signaling factor pathways controlling differentiation of progenitor cells during embryogenesis. However, we still have a rudimentary understanding of what developmental processes and genes these signaling factors regulate. Retinoic acid (RA) is a secreted signaling factor derived from retinol, an essential nutrient that is converted first to retinaldehyde and then to RA by specific enzymes. The tissue-specific location and timing of RA synthesis during vertebrate embryogenesis provides intercellular signaling information needed to stimulate differentiation of progenitor cells, thus generating mature tissues and organs. RA synthesis initiates during the early stages of body axis extension through the sequential actions of retinol dehydrogenase (Rdh10) and retinaldehyde dehydrogenase (Raldh2) that together generate RA in trunk mesoderm just anterior to the caudal progenitor zone. Body axis extension requires FGF signaling and Wnt signaling in progenitor cells at the caudal tip of the embryo, and studies on Raldh2-/- mouse embryos suggest that RA signaling sets the anterior limit of this progenitor zone by acting in the developing trunk to down-regulate FGF and Wnt signaling. While doing this, RA signaling also ensures that somites are generated in a bilaterally symmetric fashion. However, the mechanism of caudal RA action is still unclear. RA directly regulates transcription of key genes by serving as a ligand for nuclear RA receptors bound to RA response elements (RAREs). RA has traditionally been associated with induction of gene expression, but some studies suggest that RA controls body axis extension and somitogenesis through RA-mediated repression of Fgf8 and Wnt8a, and that RA acts in newly generated posterior neuroectoderm or the node rather than presomitic mesoderm. Chromatin immunoprecipitation (ChIP) studies on mouse embryos have identified RAREs upstream of the Fgf8 and Wnt8a promoters that bind RA receptors, enabling a deeper examination of the caudal RA mechanism. In this project we plan to use several mouse and zebrafish genetic models to eliminate or reduce RA, FGF, and Wnt signaling, as well as transgenic and ChIP approaches to examine Fgf8 and Wnt8a promoters. The goal of this project is to understand the mechanism through which caudal RA represses FGF and Wnt signaling to ensure normal body axis extension. Specifically, we propose to: (1) Determine the target tissue for RA repression of FGF signaling during somitogenesis and body axis extension using several genetic models; (2) Reduce Wnt signaling in RA-deficient mouse and zebrafish embryos to rescue defects in body axis extension and to examine crosstalk between RA and Wnt signaling; (3) Validate repressive functions of Fgf8 and Wnt8a RA response elements through in vivo and in vitro studies. PUBLIC HEALTH RELEVANCE: Studies focused on understanding how tissues normally develop within the embryo provide important information useful in the rational design of regenerative treatments for various human diseases. Key to this understanding is the use of genetic studies in mouse and zebrafish to learn how embryonic progenitor cells communicate with one another via secreted signaling molecules during generation of tissues and organs. By determining how the signaling molecule retinoic acid functions to regulate two other important signaling agents in progenitor cells (Fgf and Wnt), this project will help us better understand the process of embryogenesis and will provide important clues about the potential usefulness of these signaling factors in the search for effective regenerative treatments that can be used to combat human disease or aging.

描述（由申请人提供）：已经取得了巨大进展，以识别控制胚胎发生过程中祖细胞分化的信号传导因子途径。但是，我们仍然对这些信号因子调节哪些发育过程和基因有基本的了解。视黄酸（RA）是一种衍生自视黄醇的分泌信号因子，这是一种必需的营养素，首先转化为视网膜醛，然后通过特定的酶转化为RA。在脊椎动物胚胎发生过程中，组织特异性的位置和RA合成的时机提供了刺激祖细胞分化所需的细胞间信号传导信息，从而产生成熟的组织和器官。 RA合成在人体轴延伸的早期阶段通过视黄醇脱氢酶（RDH10）和视网膜脱水酶（RALDH2）的顺序作用，共同在腹部前祖细胞区的内胚层中共同产生RA。人体轴扩展需要在胚胎尾端的祖细胞中的FGF信号传导和WNT信号传导，并且对Raldh2 - / - 小鼠胚胎的研究表明，RA信号通过在发育中的型中心发动机下对下调节的FGF和WNT信号传导来设置该祖细胞区域的前部极限。在这样做的过程中，RA信号传导还确保以双侧对称方式产生节点。但是，尾ra作用的机制尚不清楚。 RA通过用作与RA反应元件（RARES）的核RA受体的配体直接调节关键基因的转录。传统上，RA与基因表达的诱导有关，但是一些研究表明，RA通过RA介导的FGF8和WNT8A的抑制来控制人体轴的扩展和体体发生，并且RA作用于新生成的后神经外动物或节点，而不是presomitic somomitic mesoderm。对小鼠胚胎的染色质免疫沉淀（芯片）研究已经鉴定了FGF8和WNT8A启动子的稀有物，它们结合了RA受体，从而可以更深入地研究尾ra机制。在这个项目中，我们计划使用几种小鼠和斑马鱼遗传模型消除或减少RA，FGF和WNT信号传导，以及转基因和芯片方法来检查FGF8和WNT8A启动子。该项目的目的是了解尾ra抑制FGF和WNT信号的机制，以确保正常的身体轴扩展。具体而言，我们建议：（1）确定使用多种遗传模型在体内生成和人体轴扩展过程中ra抑制FGF信号传导的目标组织；（2）减少缺乏RA的小鼠和斑马鱼胚胎中的Wnt信号传导，以挽救身体轴伸展中的缺陷，并检查RA和Wnt信号之间的串扰；（3）通过体内和体外研究来验证FGF8和WNT8A RA反应元件的抑制作用。公共卫生相关性：专注于了解胚胎中通常发展的组织的研究提供了对各种人类疾病的再生治疗理性设计有用的重要信息。这种理解的关键是在小鼠和斑马鱼中使用遗传研究来学习胚胎祖细胞如何通过组织和器官产生的分泌信号分子相互通信。通过确定信号传导分子视黄酸的功能如何调节祖细胞中其他两个重要的信号传导剂（FGF和WNT），该项目将有助于我们更好地了解胚胎发生过程，并将提供有关这些信号传导因素在寻找有效再生治疗中的潜在实用性的重要线索，该方法可用于抗击人类病和衰老。