Mechanisms of Estrogen Action in Enhancing Behavioral Responses to Cocaine

描述（由申请人提供）：女性更快地发展为可卡因成瘾，性激素雌激素被认为通过增强可卡因的行为效应来促进这一过程。这个项目的目标是在分子水平上了解雌激素如何增加对可卡因的行为反应。本文提出的方法是利用与可卡因成瘾有关的两种行为测量方法，条件位置偏好和致敏性来研究雌性小鼠雌激素受体和相关信号分子的功能。雌激素受体在细胞核内调节基因表达。两种核雌激素受体ER和ER在控制可卡因成瘾相关行为的大脑区域中表达。然而，目前尚不清楚这些雌激素受体或其靶基因中的哪一种增强了对可卡因的行为反应。第一组实验的目标是确定雌激素受体类型，通过使用特定的激活剂或抑制rna来促进对可卡因的行为反应。第二个目标中提出的实验将通过使用Alk蛋白活性的小分子抑制剂来测试候选雌激素调节基因Alk是否介导雌激素在增加可卡因致敏和条件性位置偏好方面的作用。最后一组拟议的实验将通过测试在存在和缺乏雌激素的情况下Alk启动子上这些蛋白质的结合，详细检查ER¿和相关转录调节蛋白LMO4调节神经元中Alk基因表达的分子机制。这些研究将提供一个新的分子途径，在大脑中由雌激素调节，与可卡因成瘾相关的行为。此外，Alk基因编码一种受体酪氨酸激酶，可用于药物开发。更好地了解雌激素靶基因及其在大脑中的调节分子机制，将有助于更好地治疗女性和男性可卡因成瘾。

DESCRIPTION (provided by applicant): Females progress more rapidly to cocaine addiction and the sex hormone estrogen is thought to contribute to this process by enhancing the behavioral effects of cocaine. The goal of this project is to understand on a molecular level how estrogen increases behavioral responses to cocaine. The approach outlined in this proposal is to study the function of estrogen receptors and associated signaling molecules in female mice using two behavioral measures related to cocaine addiction, conditioned place preference and sensitization. Estrogen receptors act in the nucleus of cells to regulate gene expression. Two types of nuclear estrogen receptors, ER¿ and ¿, are expressed in brain regions that control behaviors related to cocaine addiction. However, it is currently not known which of these estrogen receptors or their target genes enhances behavioral responses to cocaine. The goal of the first set of experiments is to determine the estrogen receptor type that promotes behavioral responses to cocaine, using specific activators or inhibitory RNAs. The experiments proposed in the second aim will test if a candidate estrogen-regulated gene, Alk, mediates the effect of estrogen in increasing cocaine sensitization and conditioned place preference, by using a small-molecule inhibitor of ALK protein activity. The last set of proposed experiments will examine in detail the molecular mechanisms of regulation of Alk gene expression in neurons by ER¿ and the associated transcriptional regulatory protein LMO4, by testing binding of these proteins at the Alk promoter in the presence and absence of estrogen. These studies will provide insight into a new molecular pathway in the brain regulated by estrogen that is relevant to behaviors related to cocaine addiction. Moreover, the Alk gene encodes a receptor tyrosine kinase that is amenable to drug development. A greater understanding of estrogen target genes and the molecular mechanisms of their regulation in the brain will lead to better strategies for differentially treating cocaine addiction in women and men.