Interaction of the Estrogen Receptor with DNA

说明(申请人提供)：类固醇激素雌激素在女性生殖和乳腺组织的发育和维持中起关键作用，但也参与心血管、骨骼和神经细胞的功能。雌激素和选择性雌激素受体调节剂广泛用于调节生育能力、缓解绝经后症状、预防和治疗乳腺癌。这些激素的生物学效应是通过与雌激素受体(ER)结合并诱导受体与驻留在靶基因中的雌激素反应元件(ERE)结合而开始的。正是这种受体与ERE的相互作用，以及多种共调节蛋白的协同作用，导致了基因表达的变化。在之前的获奖期间，我们分离和鉴定了100多个与DNA结合的Era相关的蛋白质，并表明许多这些Era相关的蛋白质与受体相互作用，增加受体与DNA的相互作用，并影响受体介导的基因表达。有趣的是，这些蛋白质不是单独发挥功能，而是形成具有各种酶和催化功能的综合网络。我们确定的一些蛋白质参与了对氧化应激的反应，氧化应激与衰老和人类疾病有关。氧化应激蛋白在维持细胞正常功能方面起着关键作用。利用分子、细胞和体内方法，我们将(1)确定雌激素是否增加C57BL/6小鼠大脑皮层氧化应激蛋白铜/锌超氧化物歧化酶(SOD1)、硫氧还蛋白(TRX)、硫氧还蛋白还原酶(TrxR)、蛋白二硫键异构酶(PDI)和无嘌呤核酸内切酶1(APE1)的表达；(2)通过器官型脑片培养确定雌激素和/或孕激素是否改变大脑皮层氧化应激蛋白的表达，(3)阐明激素诱导的氧化应激蛋白的表达是否在大脑皮层缺血保护中起作用，并确定参与这一神经保护的单个氧化应激蛋白；(4)确定氧化应激蛋白在雌激素反应基因表达中的作用。所获得的见解将有助于描绘雌激素和其他激素配体如何调节大脑中的基因表达，增强我们对大脑对一系列临床重要药物的细胞反应性的理解，并定义可能有助于保护大脑免受中风等缺血性侮辱的激素治疗。与公共健康相关：众所周知，当血液供应中断时，雌激素可以保护大脑免受损害，就像在中风期间发生的那样。然而，雌激素赋予这种保护作用的机制尚不清楚。我们有大量的初步证据表明，雌激素诱导参与这种神经保护的特定蛋白质的表达。我们将首先确定雌激素是否诱导大脑中5种特定的氧化应激蛋白的表达，然后确定这些蛋白是否参与保护大脑免受缺血。我们的研究将提供有关各种雌激素和孕激素在大脑中的作用的关键新信息，并有助于为所有年龄段的女性设计更有效的激素治疗方法。

DESCRIPTION (provided by applicant): The steroid hormone estrogen plays a critical role in the development and maintenance of female reproductive and mammary tissues, but is also involved in cardiovascular, skeletal, and neural cell function. Estrogens and selective estrogen receptor modulators are widely used in regulating fertility, alleviating postmenopausal symptoms, and preventing and treating breast cancer. The biological effects of these hormones are initiated by binding to the estrogen receptor (ER) and inducing the receptor to bind to estrogen response elements (EREs) residing in target genes. It is this interaction of the receptor with the ERE, in cooperation with multiple coregulatory proteins, that leads to changes in gene expression. During the previous award period, we isolated and identified more than 100 proteins that associate with the DNA-bound ERa and showed that a number of these ERa-associated proteins interact with the receptor, increase the interaction of the receptor with DNA, and influence receptor-mediated gene expression. Interestingly, rather than functioning individually, these proteins form integrated networks endowed with a variety of enzymatic and catalytic functions. A number of the proteins we identified are involved in responding to oxidative stress, which has been linked to aging and human disease. Oxidative stress proteins play pivotal roles in maintaining normal cell function. Using molecular, cell-based, and in vivo approaches we will (1) determine whether estrogen increases expression of the oxidative stress proteins Cu/Zn superoxide dismutase (SOD1), thioredoxin (Trx), thioredoxin reductase (TrxR), protein disulfide isomerase (PDI), and apurinic endonuclease 1 (APE1) in the cerebral cortex of C57BL/6 mice, (2) define whether estrogens and/or progestins alter the expression of oxidative stress proteins in the cerebral cortex using organotypic brain slice cultures, (3) delineate whether hormone-induced expression of oxidative stress proteins plays a role in protecting the cerebral cortex from ischemia and identify the individual oxidative stress proteins involved in this neuroprotection, and (4) define the role of oxidative stress proteins in estrogen-responsive gene expression. The insights gained will help delineate how estrogens and other hormonal ligands regulate gene expression in the brain, enhance our understanding of the cellular responsiveness of the brain to an array of clinically important pharmaceutical agents, and define hormonal treatments that may help to protect the brain from ischemic insults such as stroke. PUBLIC HEALTH RELEVANCE: It is well established that estrogen protects the brain from damage when the blood supply has been interrupted as occurs during stroke. However, the mechanisms by which estrogen confers this protective effect are unknown. We have substantial preliminary evidence to suggest that estrogen induces the expression of specific proteins involved in this neuroprotection. We will first determine whether estrogen induces expression of 5 specific oxidative stress proteins in the brain and then determine whether these proteins are involved in protecting the brain from ischemia. Our studies will provide critical new information about the role of a variety of estrogens and progestins in the brain and aid in the design of more effective hormonal treatments for women of all ages.