Molecular analysis of toxicant mediated teratogenesis

毒物介导的致畸的分子分析

• 批准号: 6590737
• 负责人: ORNELLA Ida SELMIN
• 金额: $ 14.22万
• 依托单位: UNIVERSITY OF ARIZONA
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-04-01 至 2003-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6590737
• 关键词: arsenic; biomarker; chick embryo; embryo /fetus toxicology; environmental contamination; environmental exposure; environmental toxicology; gene environment interaction; gene expression; growth /development; hazardous substances; laboratory rat; metal metabolism; teratogens; toxin metabolism; trichloroethylene; water supply

The overall goal of this research project is to assess whether specific developmental toxicants (e.g. trichloroethylene (TCE) and (As) arsenic) perturb one or more developmental pathways leading to morphologic alterations resulting in specific birth defects. Our main objective is to investigate is to investigate the molecular pathways altered by TCE that cause cardiac malformations in rat embryos. Our hypothesis is that analysis of markers at the molecular level will provide a sensitive index of environmental exposure. When these markers are chosen by empirical observation of altered expression, they are likely to indicate specific developmental pathways that are perturbed by toxicant exposure. As markers, these molecules can by used for promoter analysis and continued investigations into more proximally affected molecules in the tissue. Molecules critical to normal development can eventually be tested by genetic manipulation as a direct source of defects. Furthermore, we shall examine the similarities and differences of a separate potential teratogen (As versus TCE) in the developing embryos. Preliminary data indicate that several markers of exposure to TCE and As are perturbed in both heart and lungs during development. The PCR-Select subtractive hybridization technique that has been successfully used in our laboratory for TCE will also be used to isolate markers for As exposure. We propose to carry out the following specific aims: 1. Identify the distribution and timing of gene expression for four specific clones that were selected by screens for differential expression after exposure to teratogenic doses of TCE. The hypothesis is that miss-expressed molecules during developmentally significant patterns play a functional role in producing in producing heart defects. 2. Evaluate the sensitivity of altered marked expression in embryos exposed to varying levels of toxicants in maternal drinking water. Our objective is to determine minimum exposure levels that result in altered gene expression and use the most sensitive markers for risk assessment. 3. Clone the promoter region of the markers identified in aim 1. Identification of shared motifs would enable identification of molecules more proximal to the teratogenic activity of TCE. 4. Test the potential relationship between TCE exposure and the NMDA (N-Methyl-D-Aspartate) glutamate receptor and/or NFATc pathways as a mechanism of TCE teratogenicity. The hypothesis is that TCE-mediated heart defects may be caused by alterations in Ca++ flux involved with both molecules. 5. Identify and characterize markers of As exposure in developing embryos.

本研究项目的总体目标是评估特定的发育毒物（如三氯乙烯（TCE）和（As）砷）是否干扰一个或多个发育途径，导致形态学改变，导致特定的出生缺陷。我们的主要目的是研究TCE改变导致大鼠胚胎心脏畸形的分子途径。我们的假设是，在分子水平上的标记物的分析将提供一个敏感的环境暴露指数。当这些标志物被选择的经验观察改变表达，他们很可能表明特定的发育途径，受到干扰的毒物暴露。作为标记物，这些分子可以用于启动子分析和对组织中更近端受影响的分子的继续研究。对正常发育至关重要的分子最终可以通过遗传操作作为缺陷的直接来源进行测试。此外，我们将研究一个单独的潜在致畸剂（作为与三氯乙烯）在发育中的胚胎的相似性和差异。初步数据表明，在发育过程中，心脏和肺中暴露于TCE和As的几个标志物受到干扰。我们实验室已成功用于TCE的PCR-Select消减杂交技术也将用于分离As暴露的标记物。我们建议实现以下具体目标：1.通过筛选暴露于致畸剂量TCE后的差异表达，确定四个特定克隆的基因表达分布和时间。该假说认为，在发育显著模式期间的错误表达分子在产生心脏缺陷中起着功能性作用。2.评价暴露于母体饮用水中不同水平毒物的胚胎中标记表达改变的敏感性。我们的目标是确定导致基因表达改变的最低暴露水平，并使用最敏感的标记进行风险评估。3.克隆目标1中鉴定的标记的启动子区域。鉴定共有的基序将能够鉴定更接近TCE致畸活性的分子。4.检测TCE暴露与NMDA（N-甲基-D-天冬氨酸）谷氨酸受体和/或NFATc通路之间的潜在关系，作为TCE致畸性的一种机制。假设TCE介导的心脏缺陷可能是由与两种分子相关的Ca++通量的改变引起的。5.识别和表征发育中胚胎中As暴露的标志物。