Dissecting Estrogen Control of Sexual Differentiation of the Brain

描述(申请人提供)：在这项提案中，我将研究类固醇激素用来使终纹床核(BNST)男性化的细胞和分子机制，BNST是神经回路中的一个重要节点，产生交配和攻击等性二态行为。BNST与下丘脑和杏仁核相互连接，其结构为性别二态，男性神经元较多。经典的内分泌研究和遗传功能丧失实验表明，类固醇激素及其受体也是男性典型行为所必需的。雄激素受体(AR)在男性BNST中有较多的细胞表达。我的发现表明，在生命的最初几天，雌激素以男性特有的方式指导BNST的性别分化，部分是通过男性特有的AR调节。我建议调查两个与雌激素在BNST中性二型性产生中的作用有关的问题。1)雌激素在脑内AR表达中产生性别二型性的机制是什么？2)雌激素介导的使BNST男性化的遗传程序是什么？通过回答这些问题，我希望定义在大脑中产生特定性别细胞群的机制。目标1的目的是证明雌激素在激活BNST中男性特有的AR表达模式中的直接作用。我将利用之前发表的AR-Ipin报告小鼠，它在所有AR阳性细胞中表达LacZ，以评估AR表达中对雌激素的需求。通过染色质免疫沉淀分析(CHIP)，我将证明雌激素受体α(ERA)在男性新生儿BNST中直接募集到AR基因座。这些研究将揭示在BNST中AR表达产生性别二型性的机制I假设，除了调节AR表达外，雌激素信号还控制BNST中许多基因的性别特异性表达。目标2的目标是通过微阵列分析，在发育中的BNST中识别更多受ERcx调控的性二态基因。这些基因将为荷尔蒙在调节大脑性别分化中的作用提供重要的见解。我的实验将阐明控制大脑重要区域BNST性别分化的基本机制。许多精神疾病，如自闭症和抑郁症，都存在性别偏见。了解大脑如何经历性别分化可能会促进我们对导致许多此类疾病的基本机制的理解。

DESCRIPTION (provided by applicant): In this proposal, I will investigate the cellular and molecular mechanisms utilized by steroid hormones to masculinize the bed nucleus of the stria terminalis (BNST), an important node in the neural circuits that generate sexually dimorphic behaviors such as mating and aggression. The BNST is reciprocally connected with the hypothalamus and amygdala, and its structure is sexually dimorphic, with more neurons in males. Both classic endocrine studies, and genetic loss-of-function experiments indicate that steroid hormones and their receptors are also required for male-typical behaviors. Androgen receptor (AR) is expressed in more cells in the male BNST. My findings indicate that estrogen acts in a male-specfic manner during the first few days of life to direct sexual differentiation of the BNST, in part through male-specific regulation of AR. I propose to investigate two questions relating to the role of estrogen in generating sexual dimorphism in the BNST. 1) What are the mechanisms by which estrogen generates sexual dimorphism in AR expression in the brain? 2) What is the genetic program mediated by estrogen to masculinize the BNST? By answering these questions, I hope to define the mechanisms which generate a sex-specific cell population in the brain. The goal of Aim 1 is to demonstrate a direct role for estrogen in activating a male-specific expression pattern of AR in the BNST. I will utilize the previously published AR-IPIN reporter mice, which express LacZ in all AR-positive cells, to evaluate the requirement for estrogen in AR expression. Through chromatin immunoprecipitation analysis (ChIP), I will demonstrate the direct recruitment of estrogen receptor alpha (ERa) to the AR locus in the neonatal BNST of males. These studies will reveal the mechanisms for generating sexual dimorphism in AR expression in the BNST I hypothesize that, in addition to regulating AR expression, estrogen signaling controls the sex-specific expression of many genes in the BNST. The goal of Aim 2 is to identify additional sexually dimorphic genes regulated by ERcx in the developing BNST through microarray analysis. These genes will provide important insight into the role of hormones in regulating sexual differentiation of the brain. My experiments will elucidate the fundamental mechanisms that control sexual differentiation of an important brain region, the BNST. Many psychiatric conditions such as autism and depression present with sex-biased ratios. Understanding how the brain undergoes sexual differentiation is likely to advance our understanding of the basic mechanisms that lead to many of these disorders.