AhR- and ER-Regulated Genes in Brain Development

描述（由申请人提供）：我们的长期目标是确定发育暴露于二恶英和其他普遍存在的芳烃受体（AhR）配体改变成年期生殖功能的机制。我们最近发现，单次暴露于强效AhR配体2,3,7,8-四氯二苯并-对二恶英（TCDD）中，会干扰雄性腹侧脑室周围核（AVPV）的雌激素依赖性性别分化。AVPV控制女性黄体生成素（LH）释放模式；因此，暴露于tcdd的雄性具有与雌性相似的AVPV结构，并且在成年期表现出雌性的周期性LH释放模式。考虑到胎儿产生的睾酮产生的雌二醇（E2）负责性别分化过程，我们假设TCDD在发育过程中干扰了E2对一组基因的调节。为了验证这一假设，我们将使用Affymetrix微阵列和聚类分析来鉴定E2和TCDD调节的性别特异性基因。我们将使用“冗余模型”，测试根据我们的假设预测的针对同一组基因的不同动物治疗方法。我们将使用RT-QPCR、原位杂交组织化学、发育个体发生研究、剂量反应研究和启动子分析来验证我们的微阵列发现。我们的发现对于确定二恶英和其他普遍存在的AhR配体对生殖毒性的影响的基因，以及围产期接触TCDD以性别特异性方式破坏的其他神经功能具有重要意义。这些发现对于基于机制的风险评估以及开发药物干预措施以预防神经毒性具有重要意义。

DESCRIPTION (provided by applicant): Our long-term objective is to determine the mechanisms by which developmental exposure to dioxins and other ubiquitous arylhydrocarbon receptor (AhR) ligands alters reproductive functions in adulthood. We recently showed that a single developmental exposure to the potent AhR ligand, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), interferes with estrogen-dependent sexual differentiation of the male anteroventral periventricular nucleus (AVPV). The AVPV controls the female pattern of luteinizing hormone (LH) release; therefore, TCDD-exposed males have a female-like AVPV structure and they show the female, cyclic pattern of LH release in adulthood. Considering that estradiol (E2) derived from fetal production of testosterone is responsible for the sexual differentiation process, we hypothesize that TCDD interferes with E2 regulation of a set of genes during development. To test this hypothesis, we will use Affymetrix microarrays and cluster analysis to identify sex-specific genes that are regulated by E2 and TCDD. We will use a "redundancy model", testing different animal treatments predicted by our hypothesis to target the same set of genes. We will validate our microarray findings using RT-QPCR, in situ hybridization histochemistry, developmental ontogeny studies, dose response studies and promoter analysis. Our findings will be important for identifying genes underlying effects of dioxins and other ubiquitous AhR ligands on reproductive toxicity, as well as on other neural functions disrupted by perinatal TCDD exposure in a sex-specific manner. Such findings will be important for mechanism-based risk assessment, as well as for development of pharmaceutical interventions to prevent neurotoxicity.