Molecular Mechanisms of Endocrine Disruption in Bass

低音内分泌干扰的分子机制

• 批准号: 7228682
• 负责人: Nancy D Denslow
• 金额: $ 37万
• 依托单位: UNIVERSITY OF FLORIDA
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-08-01 至 2009-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7228682
• 关键词: biomarker; chlorohydrocarbon insecticide; endocrine disorder; endocrine disrupting compound; environmental contamination; environmental exposure; environmental toxicology; estradiol; estrogen receptors; fish; hazardous substances; hormone regulation /control mechanism; microarray technology; molecular pathology; oogenesis; pleiotropism; polymerase chain reaction; protein structure function; proteomics; receptor expression; reproductive system disorder; sperm motility; steroid biosynthesis; steroid metabolism; toxin metabolism; waste disposal

Transient and permanent reproductive dysfunction in fish has been linked to chemicals that disrupt the endocrine system, but the mechanisms involved are unclear. Many endocrine-disrupting chemicals (EDCs) interact with sex hormone receptors by acting as agonists to induce gene expression at inappropriate times or act as antagonists to prevent the normal functioning of the receptors. Other EDCs may act indirectly by altering the processes involved in regulating sex steroid synthesis and metabolism. Poor reproduction and altered plasma hormone levels have been observed in largemouth bass living in ecosystems polluted with organochlorine pesticides (OCPs), including the Superfund site at Lake Apopka and its surrounding muck farms, suggesting that OCP exposure has adversely affected their reproduction. In past research, we have identified three estrogen receptors (a, pi, and (32) in largemouth bass, which exhibit tissue specific expression and respond differently to 17-p-estradiol at the message and activity level. These differences are important to control normal reproductive function. We have evidence that EDCs can alter their normal expression and activity patterns, possibly disrupting reproduction. In addition, we have preliminary evidence that expression of enzymes involved in the synthesis and metabolism of EDCs is affected by the OCPs. The proposed studies will test the central hypothesis that exposure of largemouth bass to concentrations of OCPs found in the Lake Apopka region disrupts endocrine system function by sex hormone receptor mediated and sex hormone receptor independent mechanisms. In this proposal, we have designed a set of interrelated experiments from the organismal level where pleiotropic effects of OCPs can be measured to the cellular level where specific molecular mechanisms of action can be assessed. We are exposing largemouth bass to methoxychlor (and its metabolites), p,p' DDE, dieldrin and toxaphene. Our specific aims include 1: Develop biomarkers of exposure to organochlorinated pesticides in vivo, via the use of microarrays and novel proteomics methodologies; 2: Determine the effect of in vivo OCP exposure on LME steroid synthesis and metabolism; and 3: Evaluate the effects of OCPs on the molecular mechanisms of action of the three estrogen receptors. We plan on using exposures to compounds with known modes of action as controls to determine mode of action specific gene expression patterns against which we will compare the patterns of gene expression changes induced by the OCPs. We will check these pattern changes against reproductive endpoints including the ability of eggs to mature (germinal vesicle breakdown) and sperm function (sperm motility). Fish are useful as sentinels of environmental quality and are perfect models to monitor adverse effects in reproduction caused by contaminants in superfund sites. By extrapolation fish can report on the potential of OCPs to harm human health.

鱼类短暂和永久性的生殖功能障碍与破坏鱼类生殖系统的化学物质有关。 内分泌系统，但具体机制尚不清楚。许多内分泌干扰化学物质 (EDC) 通过作为激动剂在不适当的时间诱导基因表达来与性激素受体相互作用 或作为拮抗剂阻止受体的正常功能。其他 EDC 可能会通过以下方式间接采取行动： 改变涉及调节性类固醇合成和代谢的过程。繁殖能力差和 在生活在被污染的生态系统中的大口黑鲈中观察到血浆激素水平发生改变 有机氯农药 (OCP)，包括阿波普卡湖超级基金场地及其周围的淤泥 农场，表明 OCP 暴露对其繁殖产生了不利影响。 在过去的研究中，我们在大口黑鲈中发现了三种雌激素受体（a、pi 和 (32)）， 表现出组织特异性表达，并且在信息和活性水平上对 17-β-雌二醇有不同的反应。 这些差异对于控制正常的生殖功能很重要。我们有证据表明 EDC 可以 改变它们的正常表达和活动模式，可能会破坏繁殖。此外，我们还有 初步证据表明参与 EDC 合成和代谢的酶的表达 受 OCP 影响。拟议的研究将检验中心假设，即大口黑鲈的暴露 阿波普卡湖地区发现的 OCP 浓度会按性别扰乱内分泌系统功能 激素受体介导的和性激素受体独立的机制。在这个提案中，我们有 从有机体水平设计了一组相互关联的实验，其中 OCP 的多效性效应可以 测量到细胞水平，可以评估特定的分子作用机制。我们是 将大口黑鲈暴露于甲氧滴滴涕（及其代谢物）、p,p' DDE、狄氏剂和毒杀芬。我们的 具体目标包括 1：通过使用开发体内接触有机氯化农药的生物标志物 微阵列和新型蛋白质组学方法； 2：确定体内 OCP 暴露对 LME 的影响 类固醇的合成和代谢； 3：评估 OCP 对分子机制的影响 三种雌激素受体的作用。我们计划使用已知模式的化合物进行暴露 行动作为对照，以确定行动模式特定的基因表达模式，我们将根据这些模式 比较 OCP 诱导的基因表达变化模式。我们将检查这些模式 生殖终点的变化，包括卵子成熟的能力（生芽囊泡破裂） 和精子功能（精子活力）。鱼类是环境质量的哨兵，而且非常完美 监测超级基金场所污染物对生殖造成不利影响的模型。经过 推断鱼可以报告 OCP 危害人类健康的可能性。