Research Project 5: Mechanism and Impacts of Dioxin Resistance in Fish

研究项目5：鱼类抗二恶英的机制和影响

• 批准号: 7529679
• 负责人: MARK HAHN
• 金额: $ 33.62万
• 依托单位: BOSTON UNIVERSITY MEDICAL CAMPUS
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/7529679
• 关键词: ARNT gene; ARNT2 gene; Address; Agonist; Amino Acids; Animals; Aromatic Hydrocarbons; Aromatic Polycyclic Hydrocarbons; Aryl Hydrocarbon Receptor; Basic Science; Binding; CYP1A1 gene; Characteristics; Chemicals; Collaborations; Controlled Environment; Creosote; Cyprinodontidae; Development; Dioxins; EP300 gene; Embryo; End Point; Environment; Environmental Estrogen; Exhibits; Exposure to; Fishes; Frequencies; Fundulus heteroclitus; Gene Expression; Gene Frequency; Genes; Genetic; Genetic Polymorphism; Genetic Transcription; Genetic Variation; Grant; Haplotypes; Hepatocyte; Hypoxia; Hypoxia Inducible Factor; Individual; Link; Location; Long-Term Effects; Mammalian Cell; Mammals; Massachusetts; Measures; Modeling; Molecular; Oxidative Stress; Pathway interactions; Phenotype; Polychlorinated Biphenyls; Polymerase Chain Reaction; Population; Population Genetics; Research; Research Project Grants; Resistance; Rivers; Signal Pathway; Signal Transduction; Single Nucleotide Polymorphism; Site; Testing; Time; Toxic effect; Variant; Vertebrates; base; cDNA Arrays; cost; embryo cell; environmental stressor; in vivo; malformation; mortality; novel; research study; response; stressor; superfund site

The overall objective of the basic research proposed here is to understand the effects of long-term, multigenerational exposure to high levels of contaminants on natural populations of animals inhabiting Superfund sites. We will employ a fish model species, the Atlantic killifish Fundulus heteroclitus, which have evolved resistance to dioxin-like compounds that act through the aryl hydrocarbon receptor (AHR) at numerous sites. Killifish inhabiting New Bedford Harbor (NBH), MA, a polychlorinated biphenyl (PCB)-contaminated Superfund site, exhibit heritable resistance to altered gene expression and toxicity of 2,3,7,8- tetrachlorodibenzo-p-dioxin (TCDD) and other AHR agonists as compared to fish from a reference site, Scorton Creek, MA (SC). We have identified and cloned two distinct AHRs (AHR1 and AHR2), ARNT2, hypoxia-inducible factors (HIFs), and an AHR represser (AHRR) in killifish. The killifish AHR1 gene is highly polymorphic and AHR1 allele frequencies differ between populations of dioxin-sensitive (SC) and dioxin-resistant (NBH) fish. The studies proposed here will build on these previous findings to address ecological and biomedical/mecham'stic questions regarding the impact of chemicals at Superfund sites. The major objectives are 1) to understand mechanisms underlying differential sensitivity to the developmental toxicity of HAHs and PAHs that act through AHR-dependent signaling, and 2) to determine the impact of evolved HAH/PAH resistance on the sensitivity to other environmental stressors. The first objective will be achieved by focusing on population genetic and functional aspects of polymorphisms in AHR-pathway genes (Aims 1 & 2). The second objective will be approached by focusing on responses to environmental hypoxia (Aim 3). Specific Aims are: (1) To compare polymorphism (SNP) and haplotype frequencies at the AHR1, AHR2, AHRR, and ARNT2 loci in dioxin-sensitive and -resistant populations of killifish, (2) To determine the association of specific AHR1, AHR2, AHRR, or ARNT2 variants with the resistance phenotype of individual fish and to determine the functional differences among variants, and (3) To assess the impact of the dioxin-resistant phenotype on sensitivity to environmental hypoxia and determine the mechanistic basis for cross-talk between dioxin and hypoxia signaling pathways. The proposed research will take advantage of a unique opportunity to establish the molecular mechanisms of population-level effects of contaminants on a natural population of vertebrate animals inhabiting a Superfund site.

这里提出的基础研究的总体目标是了解长期、多代人的影响 超级基金中的动物自然种群暴露于高浓度污染物 网站。我们将使用一种鱼类模型物种，即大西洋鳉鱼 Fundulusheteroclitus，它已经进化 对通过多个位点的芳烃受体 (AHR) 起作用的二恶英类化合物具有抵抗力。 栖息在马萨诸塞州新贝德福德港 (NBH) 的鳉鱼，受到多氯联苯 (PCB) 污染 超级基金站点，对 2,3,7,8- 基因表达改变和毒性表现出遗传抗性 四氯二苯并二恶英 (TCDD) 和其他 AHR 激动剂与来自参考地点的鱼相比， 马萨诸塞州斯科顿溪 (SC)。我们已经鉴定并克隆了两个不同的 AHR（AHR1 和 AHR2），ARNT2， 鳉鱼中缺氧诱导因子 (HIF) 和 AHR 抑制因子 (AHRR)。鳉鱼 AHR1 基因是 二恶英敏感人群 (SC) 和二恶英敏感人群之间的高度多态性和 AHR1 等位基因频率存在差异 抗二恶英（NBH）鱼。这里提出的研究将建立在这些先前的发现的基础上，以解决 关于超级基金地点化学品影响的生态和生物医学/机械问题。这 主要目标是 1) 了解发育差异敏感性的机制 HAH 和 PAH 通过 AHR 依赖性信号传导起作用的毒性，以及 2) 确定 通过对其他环境压力源的敏感性，进化出 HAH/PAH 抗性。第一个目标将是 通过关注 AHR 途径基因多态性的群体遗传和功能方面来实现 （目标 1 和 2）。第二个目标将重点关注对环境缺氧的反应 （目标 3）。具体目标是：(1) 比较 AHR1 的多态性 (SNP) 和单倍型频率， 二恶英敏感和抗性鳉鱼种群中的 AHR2、AHRR 和 ARNT2 位点，(2) 确定 特定 AHR1、AHR2、AHRR 或 ARNT2 变异与耐药表型的关联 个体鱼并确定变种之间的功能差异，以及（3）评估 二恶英抗性表型对环境缺氧敏感性的影响并确定其机制基础 用于二恶英和缺氧信号通路之间的串扰。拟议的研究将利用 这是建立污染物对人口水平影响的分子机制的独特机会 栖息在超级基金地点的脊椎动物自然种群。