A role for 5-lipoxyegenase in cocaine's actions

描述(由申请人提供)：阐明尚未被广泛研究的过程在细胞对药物滥用反应的研究中的作用，可能会发现治疗成瘾的新的治疗目标。我们建议测试我们创新概念的关键组件，即炎症酶，即5-脂氧合酶(5-LOX)，影响参与可卡因行为敏化的生化和结构适应。对拟议项目概念化的重要一点是，我们意外地初步观察到，可卡因反应(即行为敏化)在对照组和5-LOX缺陷(基因敲除)小鼠之间存在差异。行为敏感化背后的神经适应性变化与那些负责加和行为的人有关。谷氨酸受体介导的神经可塑性，包括AMPA谷氨酸受体亚单位GluR1的磷酸化和表面表达，就是这些变化之一。最近发表的数据和我们的初步结果表明，5-LOX缺乏/抑制可以增加GluR1的磷酸化。因此，我们假设5-LOX抑制/缺乏将促进可卡因诱导的行为敏化，并伴随着可卡因治疗相关的GluR1磷酸化和表面表达增加的增强。在AIM 1中，我们将使用药物5-LOX抑制(MK-886处理)和5-LOX缺陷转基因(基因敲除)小鼠，研究5-LOX抑制/缺乏对可卡因诱导的GluR1磷酸化和GluR1表面表达变化的影响。分析将在单次注射可卡因后的不同时间在伏隔核(NAC)和前额叶皮质(PFC)进行(时间进程研究)。目的2将测试药物5-LOX抑制和5-LOX基因敲除是否改变可卡因行为敏化的发展阶段，而AIM 3将测试药物5-LOX抑制和5-LOX基因敲除如何影响可卡因致敏小鼠在7天后对可卡因攻击的行为和分子反应(即GluR1磷酸化和表面表达)。证明5-LOX参与成瘾的机制将指向一个未知的假定治疗靶点(例如，影响5-LOX的药物)，并将引起人们对5-LOX基因多态在药物滥用中的可能作用的关注。需要高风险、概念上有创意和创新的项目，以显著加快药物滥用和成瘾研究的进展。这项提议旨在测试创新概念的关键组成部分，即炎症酶，即5-脂氧合酶(5-LOX)，影响参与可卡因行为敏化的生化和结构适应。证明5-LOX参与成瘾的机制将指向一个新的和未被探索的假定治疗靶点(例如，影响5-LOX的药物)，而且，如果得到证实，阐明5-LOX在可卡因效应中的作用将引起人们对5-LOX基因多态性在药物滥用中的可能作用的关注。我们提出的概念是高度创新的，没有重大的前期工作可以支持它。我们相信，在资金有限的情况下，我们将能够核实我们的概念的关键组成部分，并获得必要的数据，以启动更复杂的未来翻译研究。

DESCRIPTION (provided by applicant): Elucidating the role of processes that have not been investigated extensively in studies of cellular responses to exposure to drugs of abuse may uncover novel therapeutic targets for the treatment of addictions. We propose to test critical components of our innovative concept that an inflammatory enzyme, i.e., 5-lipoxygenase (5-LOX), influences biochemical and structural adaptations involved in behavioral sensitization to cocaine. Important for conceptualization of the proposed project was our accidental preliminary observation that cocaine responses (i.e., behavioral sensitization) differ between control and 5-LOX-deficient (knockout) mice. Neuroadaptive changes underlying behavioral sensitization have been related to those responsible for addicitive behaviors. Glutamate receptor-mediated neuroplasticity, which includes the phosphorylation and surface expression of the AMPA glutamate receptor subunit GluR1, is one of these changes. Recent published data and our preliminary results demonstrated that GluR1 phosphorylation can be increased by 5-LOX deficiency/inhibition. Hence, we hypothesize that 5-LOX inhibition/deficiency will facilitate cocaine-induced behavioral sensitization and that this will be accompanied by enhancement of the cocaine treatment- associated increase in GluR1 phosphorylation and surface expression. In AIM 1, we will use pharmacological 5-LOX inhibition (treatment with MK-886) and 5-LOX deficient transgenic (knockout) mice, to investigate the effects of 5-LOX inhibition/deficiency on cocaine-induced changes in GluR1 phosphorylation and GluR1 surface expression. Analyses will be performed in the nucleus accumbens (NAc) and prefrontal cortex (PFC) at different times after a single cocaine injection (time course studies). AIM 2 will test whether pharmacological 5- LOX inhibition and 5-LOX knockout alter the development phase of behavioral cocaine sensitization, whereas AIM 3 will test how pharmacological 5-LOX inhibition and 5-LOX knockout affect behavioral and molecular (i.e., GluR1 phosphorylation and surface expression) responses of cocaine-sensitized mice to a cocaine challenge administered after 7 days of wash-out. Demonstrating the involvement of 5-LOX in mechanisms of addiction would point to an unexplored putative therapeutic target (e.g., drugs that affect 5-LOX) and would bring attention to a possible role for 5-LOX gene polymorphisms in drug abuse in general. High-risk, conceptually creative and innovative projects are needed to significantly accelerate progress in drug abuse and addiction research. This proposal is aimed at testing critical components of the innovative concept that an inflammatory enzyme, i.e., 5-lipoxygenase (5-LOX), influences biochemical and structural adaptations involved in behavioral sensitization to cocaine. Demonstrating the involvement of 5-LOX in mechanisms of addiction would point to a novel and unexplored putative therapeutic target (e.g., drugs that affect 5-LOX) and also, if confirmed, elucidation of the role of 5-LOX in cocaine's effects would bring attention to a possible role for 5-LOX gene polymorphism in drug abuse in general. The concept we propose is highly innovative and no significant prior work is available to support it. We believe that with limited funding we will be in a position to verify the key components of our concept and to obtain the necessary data to initiate more complex future translational studies.