MECHANISMS OF CHEMICAL SENSITIVITY AND RESISTANCE

化学敏感性和耐药性的机制

• 批准号: 6106445
• 负责人: MARK HAHN
• 金额: $ 14.49万
• 依托单位: BOSTON UNIVERSITY MEDICAL CAMPUS
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-04-01 至 2000-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6106445
• 关键词: alternatives to animals in research; aromatic hydrocarbon receptor; 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- 敏感和耐药的机制 四氯二苯并二恶英 (TCDD) 及相关平面卤代芳香族化合物 碳氢化合物（PHAH），尤其是长期使用后产生的耐药性 与危险废物场相关的（多代）暴露。 对致命性、生殖性、免疫毒性和免疫毒性的不同敏感性 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 自然群体中潜在的 PHAH 敏感性差异是 未知。 PHAH 的大部分生物活性是通过 与芳香烃受体 (AhR) 结合，这是一种配体激活的受体 转录因子控制相关基因的表达 生物转化以及细胞生长和分化。 表达式 Ah 受体和 AhR 依赖性其他成分的功能 特定细胞类型中的信号转导途径可能是 对于确定物种、种群和物种的敏感性至关重要 PHAH 暴露的亚人群。 解决这些问题的研究将 使用硬骨鱼 Fundulus 异斜体进行行为，已被证明 开发 TCDD 抗性并拥有许多其他优势 耐化学性脊椎动物模型。 该项目的具体目标 包括; 1) 不同PHAH敏感性/耐药性的检查 居住在新贝德福德港和其他地方的异斜 F. 网站。 抵抗力及其遗传力将在成年时表征 从环境中取样的鱼及其在环境中饲养的后代 实验室。 2）假设AhR依赖的改变 耐药性产生的信号转导途径将是 通过检查受体结合之间途径的关键步骤来解决 以及敏感和耐药的肝脏基因表达的变化 成年鱼。 要测量的参数将包括表达式 AhR 和 Ah 受体核转位蛋白 (ARNT) 蛋白及其功能 （配体结合、转化、DNA 结合）。 3）。 潜在的肝外 AhR 和 ARNT 表达和功能改变的位点将在 敏感和抵抗的鱼，重点关注内皮细胞，因为这些 似乎是 AhR 激动剂的主要靶点。 4) 内皮细胞 AhR 依赖性信号的结构和功能以及可能的改变 将在敏感和敏感的心脏组织中检查转导途径 用 TCDD 处理的抗性鱼。 5) 将审查对 PHAH 的答复 在敏感和敏感的肝细胞和内皮细胞的原代培养物中 有抵抗力的鱼。 拟议的实地和实验室研究将 提供生物医学和生态方面的研究之间的联系 超级基金站点的影响，促进鱼类作为哨兵的发展 物种和加强脊椎动物遗传标记的识别 与人群健康风险增加相关的易感性 暴露于有毒废物的亚人群。