TCDD-Induced Cardiotoxicity in Developing Zebrafish

TCDD 诱导的斑马鱼心脏毒性

• 批准号: 6989745
• 负责人: WARREN no middle name HEIDEMAN
• 金额: $ 33万
• 依托单位: UNIVERSITY OF WISCONSIN-MADISON
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-01-01 至 2007-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6989745
• 关键词: cardiogenesis; cardiotoxin; cell migration; dioxins; environmental toxicology; gene expression; gene targeting; genetic regulation; genetic transcription; heart cell; microarray technology; morphology; oligonucleotides; transcription factor; video microscopy; zebrafish

DESCRIPTION (provided by applicant): The goal of this research is to understand the molecular mechanism by which 2,3,7,8- tetrachlorodibenzo-p-dioxin (TCDD) causes morphological and functional abnormalities in the developing zebrafish heart. Exposure of newly fertilized zebrafish embryos to less than 1 ppb TCDD causes decreased ventricular size, heart rate, and cardiac output as one of the earliest signs of toxicity in the developing zebrafish. These endpoints of toxicity are followed by decreased blood flow, edema, and circulatory collapse. The proposed research will take advantage of the well known advantages of the zebrafish as a model for vertebrate development to better characterize and understand this process. The three major aims of the proposal are as follows: 1) Determine how TCDD alters the processes of heart formation. We will identify changes in morphology, the temporal and spatial patterning of heart cell gene expression, transdifferentiation, and cell migration to form the structures that make up a functional heart. 2) Determine the site of action of TCDD within the developing zebrafish that leads to these changes. For these experiments we will specifically block or activate the AHR/ARNT pathway by expressing dominant negative and constitutively active AHR proteins from tissue-specific promoters in cardiomyocytes and in endocardial cells. 3) Identify the genes that are regulated in the heart in response to TCD activation of the AHR/ARNT heterodimer. This aim is based on the assumption that because the AHR/ARNT dimer forms an active transcription factor, at least some of the responses to TCDD will involve altered transcription of specific genes. We will use DNA microarrays to identify these genes, and morpholino oligonudeotide knockdown experiments to determine the importance of these genes in responses to TCDD and in normal heart development.

描述（由申请人提供）：这项研究的目的是了解2,3,7,8-四氯二苯并-P-二恶英（TCDD）导致斑马鱼心脏中的形态和功能异常。将新受精的斑马鱼胚胎暴露于小于1 ppb的TCDD导致心室大小，心率和心输出量降低，这是发育中斑马鱼中最早的毒性迹象之一。这些毒性的终点之后是血流，水肿和循环崩溃的降低。拟议的研究将利用斑马鱼的众所周知的优势，作为脊椎动物发育的模型，以更好地表征和理解这一过程。 该提案的三个主要目的如下： 1）确定TCDD如何改变心脏形成过程。我们将确定形态的变化，心脏细胞基因表达，转变和细胞迁移的时间和空间模式，形成构成功能性心脏的结构。 2）确定在发育中的斑马鱼中TCDD的作用部位，从而导致这些变化。对于这些实验，我们将通过在心肌细胞和心内膜细胞中表达来自组织特异性启动子的主动性和组成性活性AHR蛋白来特异性阻断或激活AHR/ARNT途径。 3）确定对AHR/ARNT异二聚体TCD激活的响应在心脏中调节的基因。该目标是基于以下假设：由于AHR/ARNT二聚体形成活性转录因子，因此至少某些对TCDD的响应将涉及特定基因的转录改变。我们将使用DNA微阵列来识别这些基因，以及吗啡寡肽敲低实验，以确定这些基因在对TCDD和正常心脏发育中的反应中的重要性。