A role for 5-lipoxyegenase in cocaine's actions

描述（由申请人提供）：阐明在滥用药物暴露的细胞反应研究中尚未被广泛研究的过程的作用，可能会发现治疗成瘾的新治疗靶点。我们提议测试我们创新概念的关键组成部分，即炎症酶，即5-脂氧合酶（5-LOX），影响对可卡因行为致敏的生化和结构适应。对拟制项目概念化很重要的是我们偶然的初步观察，即可卡因反应（即行为致敏）在对照和5- lox缺陷（敲除）小鼠之间是不同的。行为敏化背后的神经适应性变化与成瘾行为相关。谷氨酸受体介导的神经可塑性，包括AMPA谷氨酸受体亚基GluR1的磷酸化和表面表达，是这些变化之一。最近发表的数据和我们的初步结果表明，GluR1磷酸化可以通过5-LOX缺乏/抑制而增加。因此，我们假设5-LOX抑制/缺乏会促进可卡因诱导的行为致敏，这将伴随着与可卡因治疗相关的GluR1磷酸化和表面表达的增加。在AIM 1中，我们将使用药理学5-LOX抑制（用MK-886治疗）和5-LOX缺乏转基因（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。在单次可卡因注射后的不同时间对伏隔核（NAc）和前额皮质（PFC）进行分析（时间过程研究）。AIM 2将测试药理学5-LOX抑制和5-LOX敲除是否会改变行为可卡因致敏的发展阶段，而AIM 3将测试药理学5-LOX抑制和5-LOX敲除如何影响可卡因致敏小鼠在7天后对可卡因刺激的行为和分子（即GluR1磷酸化和表面表达）反应。证明5-LOX在成瘾机制中的参与将指向一个尚未探索的假定治疗靶点（例如，影响5-LOX的药物），并将引起人们对5-LOX基因多态性在药物滥用中的可能作用的关注。需要高风险、概念上具有创造性和创新性的项目，以大大加快药物滥用和成瘾研究的进展。该提案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），影响对可卡因行为致敏所涉及的生化和结构适应。证明5-LOX参与成瘾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，没有重要的先前工作可以支持它。我们相信，在资金有限的情况下，我们将能够验证我们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转化研究。

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.