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而促进了这一过程。该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。在这个建议中概述的方法是研究雌激素受体和相关的信号分子在雌性小鼠中的功能，使用两种行为措施与可卡因成瘾，条件性位置偏爱和敏化。雌激素受体在细胞核中起作用以调节基因表达。两种类型的核雌激素受体，ER <$和<$，在控制可卡因成瘾相关行为的大脑区域表达。然而，目前尚不清楚这些雌激素受体或其靶基因中的哪一个增强了对可卡因的行为反应。第一组实验的目的是确定雌激素受体类型，促进可卡因的行为反应，使用特定的激活剂或抑制RNA。在第二个目标中提出的实验将测试候选雌激素调节基因Alk是否通过使用ALK蛋白活性的小分子抑制剂介导雌激素在增加可卡因致敏和条件性位置偏爱中的作用。最后一组拟议的实验将详细研究ER？和相关的转录调节蛋白LMO 4在神经元中调节Alk基因表达的分子机制，通过测试这些蛋白在存在和不存在雌激素的情况下在Alk启动子处的结合。这些研究将提供对大脑中由雌激素调节的新分子途径的深入了解，该途径与可卡因成瘾相关的行为有关。此外，Alk基因编码适合药物开发的受体酪氨酸激酶。对雌激素靶基因及其在大脑中调节的分子机制的更深入了解将导致更好的策略，用于区别治疗女性和男性的可卡因成瘾。 公共卫生相关性：男性和女性对包括可卡因在内的许多滥用药物的反应不同。了解这些差异的生物学基础对于找到对男女都有效的可卡因成瘾治疗方法非常重要。这项拟议中的研究将进一步了解性激素雌激素如何在女性大脑中发挥作用，以促进与可卡因成瘾有关的行为。

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. PUBLIC HEALTH RELEVANCE: Males and females respond differently to many drugs of abuse, including cocaine. Understanding the biological basis of these differences is important for finding treatments for cocaine addiction that will be effective in both sexes. The proposed research will further our understanding of how the sex hormone estrogen functions in the brain of females to promote behaviors related to cocaine addiction.