MECHANISMS OF CHEMICAL SENSITIVITY AND RESISTANCE

化学敏感性和耐药性的机制

• 批准号: 5211395
• 负责人: MARK HAHN
• 金额: --
• 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/5211395
• 关键词: alternatives to animals in research; cancer risk; carbopolycyclic compound; cytochrome P450; dioxins; environment related neoplasm /cancer; epidermal growth factor; fish; gel mobility shift assay; gene expression; growth factor receptors; histopathology; immunocytochemistry; in situ hybridization; industrial waste; northern blottings; pharmacokinetics; polymerase chain reaction; transcription factor; water pollution; western blottings

The overall objective of the proposed research is to understand the mechanisms of animal sensitivity and resistance to 2,3, 7, 8- tetrachlorodibenzo-p-dioxin (TCDD) and related planar halogenated aromatic hydrocarbons (PHAH), especially resistance developing after long-term (multi-generation) exposure associated with hazardous waste sites. Differential sensitivity to the lethal, reproductive, immunotoxic, and carcinogenic effects of PHAH occurs in species, population, strains, sexes, and developmental stages of animals. The genetic and epigenetic mechanisms underlying differential PHAH sensitivity in natural populations are unknown. Most of the biological activity of PHAH is mediated through binding to the aromatic hydrocarbon receptor (AhR), a ligand-activated transcription factor that controls the expression of genes involved in biotransformation and in cell growth and differentiation. The expression and function of Ah receptors and other components of the AhR-dependent signal transduction pathway in specific cell types are likely to be critical in determining sensitivity of species, populations, and subpopulations to PHAH exposure. Studies to address these issues will be conduct using the teleost Fundulus heteroclitus, which has been shown to develop TCDD resistance and possesses a number of other advantages as a vertebrate model for chemical resistance. Specific aims of the project include; 1) Examination of differential PHAH sensitivity/resistance in populations of F. heteroclitus inhabiting new Bedford harbor and other sites. The resistance and its heritability will be characterized i adult fish sampled from the environment and their progeny raised in the laboratory. 2) The hypothesis that alterations in the AhR-dependent signal transduction pathway underlie the development of resistance will be addressed by examining key steps in the pathway between receptor binding and changes in gene expression in the liver of sensitive and resistant adult fish. Parameters to be measured will include the expression of the AhR and Ah receptor nuclear translocator (ARNT) proteins and their function (ligand binding, transformation, DNA binding). 3). Potential extrahepatic sites of altered AhR and ARNT expression and function will be evaluated in sensitive and resistant fish, focusing on endothelial cells, as these appear to be primary targets for AhR agonists. 4) Endothelial cell structure and function and possible alterations in the AhR-dependent signal transduction pathway will be examined in heart tissue of sensitive and resistant fish treated with TCDD. 5) Responses to PHAH will be examined in primary cultures of hepatocytes and endothelial cells from sensitive and resistant fish. The proposed field- and laboratory-based studies will provide a link between biomedical and ecological aspects of research on the impact of superfund sites, enhancing the development of fish as sentinel species and enhancing the identification of vertebrate markers of genetic susceptibility associated with increased health risks in populations and subpopulations exposed to toxic waste.

拟议研究的总体目标是了解 动物对2，3，7，8- 四氯二苯并对二恶英（TCDD）和相关平面卤代芳族化合物 碳氢化合物（PHAH），特别是长期使用后产生的抗性 （多代）接触危险废物场地。 对致死性、生殖性、免疫毒性和 PHAH的致癌作用发生在物种、种群、品系、性别 和动物的发育阶段。 遗传和表观遗传机制 在自然人群中潜在的差异PHAH敏感性是 未知 PHAH的大部分生物活性通过以下途径介导： 与芳香烃受体（AhR）结合，配体激活 一种转录因子，它控制参与 生物转化以及细胞生长和分化。 表达 和AhR依赖性细胞的其他成分的功能 特定细胞类型中信号转导途径可能 在确定物种、种群和 暴露于PHAH的亚群。 为解决这些问题， 使用硬骨鱼Fundulus heteroclitus进行，这已被证明是 发展TCDD耐药性，并具有许多其他优势， 脊椎动物耐化学性模型。 项目的具体目标 包括：1）检查不同PHAH敏感性/抗性， 种群的F.栖息在新贝德福德港和其他 网站. 抗性及其遗传力将在成年后进行表征。 从环境中取样的鱼类及其在 实验室 2)假设AhR依赖性的 信号转导途径的基础上的发展的阻力将是 通过检查受体结合之间途径中的关键步骤来解决 以及敏感和耐药小鼠肝脏中基因表达的变化 成鱼 待测量的参数将包括 AhR和Ah受体核转运蛋白（ARNT）及其功能 （配体结合、转化、DNA结合）。 3）。 潜在肝外 改变AhR和ARNT表达和功能的位点将在 敏感和耐药的鱼，重点是内皮细胞，因为这些 似乎是AhR激动剂的主要靶标。 4)内皮细胞 结构和功能以及AhR依赖性信号的可能改变 转导途径将在敏感的心脏组织中进行检查， 用四氯二苯并对二恶英处理过的鱼 5)将审查对PHAH的答复 在来自敏感性和非敏感性的肝细胞和内皮细胞的原代培养物中， 抵抗性鱼类 拟议的实地和实验室研究将 在生物医学和生态学方面的研究之间建立联系， 超级基金地点的影响，加强渔业作为前哨的发展 物种和加强脊椎动物遗传标记的鉴定 与人群健康风险增加相关的易感性， 暴露于有毒废物的亚群。